CROSS-REFERENCE TO RELATED APPLICATIONS

[001] This application claims priority of US provisional patent application 62/287857 filed on January 27, 2018, the specification of which is hereby incorporated by reference.

BACKGROUND

(a) Field

[002] The subject matter disclosed generally relates to in vitro method for enhancing engraftment of neurosensory precursor ceils and in vitro methods for protecting isolated neurosensory precursor cells from prostaglandin E2 toxicity.

(b) Related Prior Art

[003] Cell transplantation is a promising approach to replace tissue lost as a consequence of retinal degenerative diseases. For example, specialized NPCs such as retinal precursor cells are being investigated for use in retinal diseases such as age- related macular degeneration (AMD) and retinitis pigmentosa (RP) ( lassen, 2015). However, it has become evident that the survival and functional integration rate of transplanted NPCs and in particular specialized retinal precursor cells, remains low (1- 3% and 3.5%, respectively; Stone et aL, 2013 and Warre-Cornish ef aL, 2014). The factors that inhibit transplanted cell engraftment remain largely unknown, in part because many adverse factors could be at play during in vivo experiments. These factors include immune-rejection, sub-optimal type of NPC, trauma during ceil delivery, nutritional deficits in the target tissue and toxic compounds secreted from the target tissue (Ma et a!., 201 1 ; West et al., 2012; Singh et al., 2013). To highlight one factor, many neurodegenerative tissues undergo necrosis and as such release toxic metabolites such as the by-products of phospholipids released by the porous plasma membrane (e.g. prostaglandins; Ricciotti and FitzGerald, 201 1 ), free nucleic acids (Cavassani et al., 2008) and high mobility group box 1 protein (HMGB1 ; Scaffidi et al., 2002). The release of such toxic factors is of particular concern as it triggers inflammatory signals which ultimately lead to more ceil death (Zhou and Yuan, 2014). Although numerous factors are released from necrotic tissues, prostaglandins and specifically prostaglandin E2 (PGE2) has been shown to stimulate cell death in several cell culture systems, it has been suggested that during necrosis, as ceil wails break down, membrane-derived arachidonic acid is released. This occurs with upregulation of the enzyme eydooxygenase-2 (COX-2) triggered by cell death signalling and leads to the conversion of arachidonic acid to PGE2 (e.g., Ricciofti and FifzGerald, 201 1 ; Takadera ef a!., 2004 and Miyagishi et ai., 2013).

[004] A recently characterized anti-aging giycopeptide (AAGP™) as a potential protective agent, is a small, stable, synthetic analog of anti-freeze protein (AFP). AFP has been shown to protect cells against extreme conditions has been shown to protect ceils for example, against exposure to extreme temperatures and ultraviolet irradiation. AAGP™ compounds are gem difluorinated C-glycopeptides which have also been proposed to have applicability under harsh cellular stresses, such as nutrient deprivation, high temperature and cryopreservation, oxidative stress from hydrogen peroxide (H9G2), UV irradiation, and inflammation. The cytoprotective effect of this AAGP™ compound is tested in isolated NPC.

[005] Therefore, there exists a need in the art for means of improving transplanted NPC engraftment.

SU MARY

[006] According to an embodiment, there is provided an in vitro method for enhancing engraftment of neurosensory precursor cells comprising the step of:

a) contacting an isolated neurosensory precursor cell prior to a transplantation in a subject in need thereof, with a gem-difluorinated C-glycopeptide compound of general formula I, or a pharmaceutically acceptable base, addition salt with an acid, hydrate or solvate thereof, and then washing the isolated neurosensory precursor cells to remove the compound:

in which:

N is an integer between 1 and 5,

R ⁴ - H , AAL or AAi-AA ₂ ,

R ^IJ - OH, AAi, or AA1-AA2,

AAi and AA ₂ independently represent amino acids with a non-po!ar side chain and

R\ R ² , R ³ are independent groups in which two of R ¹ , R ² and R ³ are selected from H, CH ₃ , CH ₂ Pb, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ )2 or CH(CH ₃ )CH ₂ CH3 and the remaining R ¹ , R ² , R ³ is

in which:

n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' - H, OR, N ₃ , NR'R", or SR' ^: where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl or acetate group,

R', R" independently = H, alkyl, allyl, benzyl, tosylate group,

C(=0)-alkyl or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃₎ CH ₂ OH, CH ₂ ~giycoside group or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁷ = OH, OGP", NH ₂ , N ₃ , NHGP' or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyidimethyisiiyi, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function,

H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

/wvr

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y - H, OR, N ₃ . NR'R", or SR"\

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group, R', R" independently = H, alkyl, allyl, benzyl tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ Is H, CH ₃ , CH ₂ OH, CH ₂ -glycoslde group, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tertbutyidimethylsilyi, terf-butyldiphenyisilyi, or acetate group,

R ⁷ = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyidimethylsilyi, tert-butyldiphenylsilyl, or acetate group,

R ^s is a hydrogen atom H or a free or protected alcohol function,

R ³ - H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

>2_

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y - H, OR, N _3> NR'R", or SR'",

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn, R'" = H, aikyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in v/hich GP is a protector group selected from aikyl, benzyl, trimelhylsilyi, iert-butyldimethylsiiyl, tert-butyldiphenylsilyi, or acetate group,

R ⁷ = OH, OGP\ NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from aikyl, benzyl, trimethy!si!y!, tertbutyldimethylsiiyi, tert-butyidiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function,

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y H, OR, N ₃ , NR'R", or SR' '

where R - H, benzyl, trimethylsi!y!, tert-butyidimeihylsiiyl, tert- butyidiphenylsilyl, or acetate group,

R', R" independently = H, aikyl, ailyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyi, or acetate group, R ⁶ is H, CH _3l CH ₂ OH, CH ₂ -giycoside group, or CH ₂ -OGP in which GP is a protector group selected from aikyl, benzyl, trimethylsilyl, tert-butyidimethylsilyi, tert-butyldiphenylsilyi, or acetate group,

R ⁷ - OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyi, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyi, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function.

[007] According to another embodiment, there is provided an in vitro method for protecting isolated neurosensory precursor cells from prostaglandin E2 toxicity comprising the step of:

a) contacting an isolated neurosensory precursor ceils with a gem-dsfluorinated C- glycopeptide compound of general formula I , or a pharmaceutically acceptable base, addition salt ^' with an acid, hydrate or solvate thereof, and then washing the isolated neurosensory ceils to remove the compound:

in which:

N is an integer between 1 and 5,

R ⁴ ^ H, AAi, or AA AA _2[

AAi and AA ₂ independently represent amino acids with a non-polar side chain and

R , R ² , R ³ are independent groups in which two of R ¹ , R ² and R ³ are selected from H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ or CH(CH ₃ )CH ₂ CH ₃ and the remaining R ¹ , R ² , R ³ is

Y'

in which:

n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' = H, OR, N ₃ , NR'R", or SR'",

where R = H, benzyl, trimethyisilyl, tert-butyldimethylsilyl, tert- buty!diphenylsi!y! or acetate group,

R', R" independently = H, alkyl, ai!y!, benzyl, tosylate group,

C(=0)-alkyl or C(=0)-Bn,

R'" = H, alkyi, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -giycoside group or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethyisilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ^; = OH, OGP', NH ₂ , N ₃ , NHGP' or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethyisilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁸ is a hydrogen atom H or a free or protected alcohol function, and

if R ¹ - R ² - H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ³ ~

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y = H, OR, N ₃ , NR'R", or SR"\

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyidipheny!silyi, or acetate group,

R\ R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in v/hich GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R- = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function, if R ¹ = R ³ = H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ² ^

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y = H, OR, N ₃ , NR'R", or SR"\

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyidipheny!silyi, or acetate group,

R\ R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in v/hich GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R- = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function, if R ² = R ³ = H, CH ₃ , CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R -

Y'

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y H, OR, N ₃ , NR'R", or SR' ' ',

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyidiphenylsilyi, or acetate group,

R\ R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in v/hich GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R- = OH, OOP', NH N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyidimethylsiiyi, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function

wherein the compound protects the isolated neurosensory precursor cells from prostaglandin E2 toxicity.

[008] The contacting may be prior to a transplantation in a subject in need thereof.

[009] The compound of formula I may be a compound of formula II:

in which: N is an integer between 1 and 5,

and

R , R ² , R ³ are independent groups in which two of R ¹ , R ² and R ^A are selected from H, CH ₃ and the remaining R ¹ , R ² and R ³ is

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y ^! - H, OR, N ₃ , NR'R" or SR"',

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R', R" independently = H, alky!, ally!, benzyl, tosyiate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, aikyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, CH ₂ -OGP in which GP is a protector group selected from alkyi, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R' OH, OGP, NH ₂ , N ₃ , NHGP', NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyldimethylsllyl, tert-butyldiphenylsslyl or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function, and

if R ¹ = R H or CH ₃ ,

then R ³

in which n is an integer between 3 and 4,

Y, Y' are independent groups

in -which Y, Y' = H, OR, N ₃ , NR'R", or SR' ' ', where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, ally!, benzyl, tosylate group,

C(=0)-alkyl, or

C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyidiphenylsilyi, or acetate group, R ⁷ =OH, OGP', NH ₂ , N ₃ , NHGP', NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁸ is a hydrogen atom H or a free or protected alcohoi function, if R ¹ = R ³ ~ H or CH ₃ ,

then R ² =

n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' = H, OR, N ₃ , NR'R", SR'",

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, ailyl,

Bn, tosylate, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁷ - OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁸ is a hydrogen atom H or a free or protected alcohol function, if R ² = R ³ = H or CH ₃ ,

then R ¹ ™

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in -which Y, Y' H, OR, N ₃ , NR'R", or SR' ' ',

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimetby!siiyi , tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁷ -OH, OGP, NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyidimethyisiiyi, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom or a free or protected alcohol function.

[010] The compound of formula I may be a compound of formula III:

(ill).

[011] The isolated neurosensory precursor cell may be contacted with the compound for at least 1 hour.

[012] The concentration of the compound may be from about 1 mg/ml to about 5 mg/ml.

[013] The concentration of the compound may be from about 1 mg/ml to about 3 mg/ml, or from about 3 mg/ml to about 5 mg/ml.

[014] The isolated neurosensory precursor cell may be a photoreceptor precursor cell.

[015] According to another embodiment, there is provided an isolated neurosensory precursor ceil prepared according to the method of the present inventon.

[016] According to another embodiment, there is provided a method of transplanting isolated neurosensory precursor ceil in a subject in need thereof comprising the steps of a) transplanting an isolated isolated neurosensory precursor cell prepared according to the method of the present invention, in the subject in need thereof.

[017] The method may further comprise the step of :

b) transplanting the treated isolated neurosensory precursor cell from step a) in the subject in need thereof, wherein the subject may be receiving an immunosuppressant drug.

[018] The immunosuppressant drug may be daclizumab, sirolimus, tacrolimus, cyclosporine, or a combination thereof.

[019] The subject may be a human subject.

[020] According to another embodiment, there is provided a method of treating a retinal degenerative disease comprising the step of :

a) transplanting an isolated neurosensory precursor cell prepared according to the method of the present invention in the subject in need thereof.

[021] The retinal degenerative disease may be age-related macular degeneration (AMD), retinitis pigmentosa (RP), retinal vasculitis, or sarcoidosis.

[022] According to another embodiment, there is provided a use of an isolated neurosensory precursor ceil prepared according to the method of the present invention, for transplantation to a subject in need thereof.

[023] According to another embodiment, there is provided a use of an isolated neurosensory precursor ceil prepared according to the method of the present invention, for treatment of a retinal degenerative disease in a subject in need thereof.

[024] The retinal degenerative disease may be age-related macular degeneration (AMD), retinitis pigmentosa (RP), retinal vasculitis, or sarcoidosis.

[025] According to another embodiment, there is provided an isolated neurosensory precursor ceil according to the method of the present invention, for transplantation to a subject in need thereof.

[026] The isolated neurosensory precursor ceil may be a photoreceptor precursor ceil. [027] According to another embodiment, there is provided an isolated neurosensory precursor cell contacted with a gem-difluorinated C-giycopeptide compound of general formula I, or a pharmaceutically acceptable base, addition salt v/ith an acid, hydrate or solvate thereof :

in which:

N is an integer between 1 and 5,

R ⁴ = H, AAi, or AA AA,

Ai and AA ₂ independently represent amino acids with a non-polar side chain and

R ¹ , R ² , R ³ are independent groups in which two of R ¹ , R ² and R ³ are selected or CH(CH ₃ )CH ₂ CH ₃ and the remaining R ¹ ,

in which:

n is an integer between 3 and 4, Y, Y' are independent groups

in which Y, Y' - H, OR, N ₃ , NR'R", or SR"',

where R = H, benzyl, trimethylsilyl, tert-bLityidimethylsiiyi, tert- butyldiphenylsilyl or acetate group,

R', R" independently = H, aiky!, allyl, benzyl, tosylate group,

C(=0)~aikyl or C(=0)-Bn,

R'" = H, alkyi, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -giycoside group or CH ₂ -OGP in which GP is a protector group selected from aikyl, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁷ = OH, OGP", NH ₂ , N ₃ , NHGP' or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyidimethyisiiyi, tert-butyldiphenylsilyl, or acetate group, R ⁸ is a hydrogen atom H or a free or protected alcohol function, and

if R ¹ - R ² - H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R°=

in which: n is an integer between 3 and 4,

Y, Y ^! are independent groups

in which Y, Y' - H, OR, N ₃ , NR'R", or SR' where R = H, benzyl, trimethy!si!yi, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R\ R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" - H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tertbutyidimethylsilyi, tert-butyldiphenylsilyl, or acetate group,

R ⁷ - OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyidimethylsilyi, terf-butyldiphenyisilyi, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function, if R ¹ - R ³ = H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) _2! CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ^2:

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y - H, OR, N ₃ . NR'R", or SR"\

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyldiphenylsilyl, or acetate group, R', R" independently = H, alkyl, allyl, benzyl tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ Is H, CH ₃ , CH ₂ OH, CH ₂ -glycoslde group, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyidimethylsilyi, terf-butyldiphenyisilyi, or acetate group,

R ⁷ = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyidimethylsiiyi, tert-butyldiphenylsilyi, or acetate group,

R ^s is a hydrogen atom H or a free or protected alcohol function, if R ² - R ³ - H, CH ₃ , CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ¹ -

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y H, OR, N ₃ , NR'R", or SR' ' ',

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsilyi, tert- butyldiphenylsilyi, or acetate group,

R', R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn, R'" = H, aikyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in which GP is a protector group selected from aikyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁷ - OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyi, benzyl, frimethylsiiyi, terfbutyidimethylsiiyi, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function.

The compound of formula 1 may be a compound of formula 11:

in which: N is an integer between 1 and 5,

and

R ¹ , R ² , R ³ are independent groups in which two of R ¹ , R ² and R ³ are selected from H, CH ₃ and the remaining R ¹ , R ² and R ³ is

in which : n is an integer between 3 and 4, Y, Y' are independent groups

in which Y, Y' - H, OR, N ₃ , NR'R" or SR"\

where R = H, benzyi, trimethylsilyl, tert-butyldimethylsilyl, tert-butyidiphenylsiiyi, or acetate group,

R\ R" independently = H, alky!, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁷ =OH, OGP', NH ₂ , N ₃ , NHGP', NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyi, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function, and

if R ¹ - R ² - H or CH ₃ ,

then R°=

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' - H, OR, N ₃ , NR'R", or SR' where R = H, benzyl, irimetby!siiyi, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R\ R" independently = H, alkyi, aliyi, benzyl, tosylate group,

C(=0)-alk l, or

C(=0)-Bn,

R'" = H, alkyi, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, CH ₂ -OGP in which GP is a protector group selected from aikyl, benzyl, trimethylsilyl, teri-butyidimethy!siiyi, tert- butyidiphenylsilyi, or acetate group,

R ⁷ -OH, OGP', NH ₂ , N ₃ , NHGP', NGP'GP" in which GP' and GP" are independently selected from alkyi, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁸ is a hydrogen atom H or a free or protected alcohol function,

H o CH ₃ ,

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' - H, OR, N ₃ . NR'R", SR"\

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyi, allyl, Bn, tosyiate, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, or CH ₂ -OGP in which GP is a protector group selected from alkyi, benzyi, irimethy!siiyi, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁷ = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyidimethy!siiyi, tert-butyldiphenylsilyl, or acetate group, R ⁸ is a hydrogen atom H or a free or protected alcohol function, if R ² ~ R ³ ~ H or CH ₃ ,

then R ¹ =

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' H, OR, N _3l NR'R", or SR' ' ',

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, ally!, benzyl, tosyiate group,

C(=0)-alkyl, or C(=0)-Bn,

R"' = H, alkyi, or acetate group, R ⁶ is selected from H, CH ₃ , CH ₂ QH, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl , tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁷ -OH, OGP, NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyidimethylsiiyi, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom or a free or protected alcohol function.

[029] The com ound of formula 1 may be a compound of formula il l:

(il l).

[030] The isolated neurosensory precursor cell may be contacted with from about from about 0.01 mg/ml to about 5 mg/ml of the compound of formula I, formula Π or formula III .

[031 ] The isolated neurosensory precursor cell may be contacted with from about from about 1 mg/ml to about 5 mg/ml, or from about 1 mg/ml to about 3 mg/ml, or from about 3 mg/mi to about 5 mg/ml of the compound of formula I , formula II or formula I II . [032] The isolated neurosensory precursor cell may be contacted with the compound for at least 1 hour.

[033] The isolated neurosensory precursor cell may be washed to remove the compound of formula I, II or IN.

[034] The isolated neurosensory precursor cell may be a photoreceptor precursor cell.

[035] According to another embodiment, there may be provided a use of a gem- difiuorinated C-glycopepfide compound of general formula I, or a pharmaceutically acceptable base, addition salt with an acid, hydrate or solvate thereof, for enhancing engraftment of isolated neurosensory precursor cell in a subject in need thereof:

in which:

N is an integer between 1 and 5,

R ⁴ ^ H, AA or AArAA _2,

R ⁵ = OH, AA-i, or AA AA _2i

AAi and AA ₂ independently represent amino acids with a non-polar side chain and

R , R ² , R ³ are independent groups in which two of R ¹ , R ² and R ³ are selected from H, CH _3> CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ or CH(CH ₃ )CH ₂ CH ₃ and the remaining R ¹ , R ² , R ³ is

Y'

in which:

n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' = H, OR, N ₃ , NR'R", or SR'",

where R = H, benzyl, trimethyisilyl, tert-butyldimethylsilyl, tert- buty!diphenylsi!y! or acetate group,

R', R" independently = H, alkyl, ai!y!, benzyl, tosylate group,

C(=0)-alkyl or C(=0)-Bn,

R'" = H, alkyi, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -giycoside group or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethyisilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ^; = OH, OGP', NH ₂ , N ₃ , NHGP' or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethyisilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁸ is a hydrogen atom H or a free or protected alcohol function, and

if R ¹ - R ² - H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ³ ~

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y = H, OR, N ₃ , NR'R", or SR"\

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyidipheny!silyi, or acetate group,

R\ R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in v/hich GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R- = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function, if R ¹ = R ³ = H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ² ^

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y = H, OR, N ₃ , NR'R", or SR"\

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyidipheny!silyi, or acetate group,

R\ R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in v/hich GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R- = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function, if R ² = R ³ = H, CH ₃ , CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R -

Y'

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y H, OR, N ₃ , NR'R", or SR' ' ',

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyidiphenylsilyi, or acetate group,

R\ R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyi, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in v/hich GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyidimetby!silyi, tert-butyldiphenylsilyl, or acetate group,

R- = OH, OOP', NH N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function.

[036] According to another embodiment, there is provided an use of a gem- difiuorinated C-glycopeptide compound of general formula I, or a pharmaceutically acceptable base, addition salt v/ith an acid, hydrate or solvate thereof, for protecting isolated neurosensory precursor cell from prostaglandin E2 toxicity prior to transplantation in a subject in need thereof:

in which:

N is an integer between 1 and 5,

R ⁴ = H, AAi, or AA AA ₂ ,

R ⁵ ~ OH, AA-i, or AA AA _2j

A and AA ₂ independentiy represent amino acids with a non-polar side chain and

R ¹ , R ² , R ³ are independent groups in which two of R ¹ , R ² and R ³ are selected from H, CH ₃₎ CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ or CH(CH ₃ )CH ₂ CH ₃ and the remaining R ¹ , R ² , R ³ is

in which:

n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y" = H, OR, N ₃ , NR'R", or SR"',

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyldipheny!silyl or acetate group, R', R" independently = H, alkyi, aiiyi, benzyl tosyiate group,

C(=0)-alkyl or C(=0)-Bn,

R'" = H, alkyi, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -giycoside group or CH ₂ -GGP in which GP is a protector group selected from alkyi, benzyl, trimethylsilyl, tert- butyidimethylsiiyi, tert-butyldiphenylsilyl, or acetate group, R ⁷ = OH, OGP', NH ₂ , N.3, NHGP' or NGP'GP" in which GP' and GP" are independently selected from alkyi, benzyl, trimethylsilyl, tert- butyidimethylsiiyi, tert-butyldiphenylsilyl, or acetate group, R ⁸ is a hydrogen atom H or a free or protected alcohol function, and

if R ¹ - R ² - H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ³ =

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y - H, OR, N ₃ , NR'R", or SR'",

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyi, allyl, benzyl, tosyiate group, C(=0)-alkyl, or C(=0)-Bn, R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in v/hich GP is a protector group seiected from alkyl, benzyl, trimethyisilyl, tertbutyldimethyisilyi, iert-butyidiphenyisiiyi, or acetate group,

R ⁷ - OH, OGP, NH ₂ , N ₃ , NHGP, or NGP'GP" in which GP and GP" are independently seiected from alkyl, benzyl, trimethyisilyl, tertbutyldimethyisilyi, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function,

R ³ ~ H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y - H, OR, N ₃ , NR'R", or SR"',

where R - H, benzyl, trimethyisilyl, tert-butyidimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, ally!, benzyl, tosylate group, C(=0)~alky!, or C(=0)-Bn,

R'" = H, alkyl, or acetate group, R ⁶ is H, CH _3l CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in which GP is a protector group selected from aikyl, benzyl, trimethyisilyl, tert-butyidimethylsilyi, tert-butyldiphenylsilyl, or acetate group,

R ⁷ - OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethyisilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function, if R ² ~ R ³ = H, CH ₃ , CH(CH ₃ ) _2> CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R -

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y H, OR, N ₃ , NR'R", or SR' ' ',

where R = H, benzyl, trimethyisilyl, tert-butyidimethylsilyi, tert- butyldiphenylsilyl, or acetate group,

R\ R" independently = H, aikyl, ally!, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group, R ⁶ is H, CH _3l CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in which GP is a protector group selected from aikyl, benzyl, trimethyisilyl, tert-butyidimethylsilyi, tert-butyldiphenylsilyi, or acetate group,

R ⁷ - OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyi, benzyl, trimethyisilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyi, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function.

The subject may be a human subject.

The isolated neurosensory precursor ceil may be a photoreceptor precursor cell. The compound of formula I may be a compound of formula Π:

in which: N is an integer between 1 and 5,

and

R ¹ , R ² , R ³ are independent groups in which two of R ¹ , R ² and R ^; 3 are selected from H, CH ₃ and the remaining R ¹ , R ² and R ³ is

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y" = H, OR, N ₃ , NR'R" or SR'",

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R', R" independently - H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R"' = H, alkyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R- =OH, OGP', NH ₂ , N ₃ , NHGP', NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function, and

if R ¹ = R ² = H or CHs,

then R ,3.

n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' = H, OR, N ₃ , NR'R", or SR" ' ',

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyidiphenylsiiyi, or acetate group,

R', R" independently = H, alkyl, allyl, benzyl, tosylate group,

C(=0)-alkyl, or

C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyidiphenylsilyi, or acetate group,

R ⁷ -OH, OGP', NH ₂ , N ₃ , NHGP', NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function,

H or CH ₃ ,

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' = H, OR, N ₃ , NR'R", SR'",

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, allyl,

Bn, tosyiate, C(=0)~a!ky!, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁷ = OH, OGP, NH ₂ , N ₃₎ NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁸ is a hydrogen atom H or a free or protected alcohol function, if R ² ~ R ³ = H or CH ₃

then R ¹ ^

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' H, OR, N ₃ , NR'R", or SR' ' ',

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyidiphenylsiiyi, or acetate group,

R', R" independently = H, alkyl, allyl, benzyl, tosylate group,

C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, irimetby!siiyi , tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁷ =OH, OGP', NH ₂₎ N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom or a free or protected alcohol function.

[040] The compound of formula I may be a compound of formula III:

[041] The isolated neurosensory precursor ceil may be contacted 'with from about from about 0.01 mg/ml to about 5 mg/ml of the compound of formula I, formula II or formuia 111.

[042] The isolated neurosensory precursor cell may be contacted with from about from about 1 mg/ml to about 5 mg/ml, or from about 1 mg/ml to about 3 mg/ml, or from about 3 mg/ml to about 5 mg/ml of the compound of formula I, formula II or formula III.

[043] The isolated neurosensory precursor ceil may be contacted with the compound for at least 1 hour.

[044] The isolated neurosensory precursor ceil may be 'washed to remove the compound of formula I, II or HI.

[045] The isolated neurosensory precursor cell may be a photoreceptor precursor cell. [046] The use may be for the treatment of a retinal degenerative disease in a subject in need thereof .

[047] The retinal degenerative disease may be age-related macular degeneration (AMD), retinitis pigmentosa (RP), retinal vasculitis, or sarcoidosis.

[048] According to another embodiment, there is provided an gem-difluorinated C- giycopeptide compound of general formula I, or a pharmaceutically acceptable base, addition salt with an acid, hydrate or solvate thereof, for use in enhancing engraftment of an isolated neurosensory precursor cell in a subject in need thereof:

in which:

N is an integer between 1 and 5,

R ⁴ = H, AAi, or AAi-AA _2,

R ⁵ = OH, AA-i, or AA AA ₂ ,

AAi and AA ₂ independently represent amino acids with a non-polar side chain and

R ¹ , R ² , R ⁵ are independent groups in which two of R ¹ , R ² and R ³ are selected from H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ or CH(CH ₃ )CH ₂ CH ₃ and the remaining R ¹ , R ² , R ³ is

Y'

in which:

n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' = H, OR, N ₃ , NR'R", or SR'",

where R = H, benzyl, trimethyisilyl, tert-butyldimethylsilyl, tert- buty!diphenylsi!y! or acetate group,

R', R" independently = H, alkyl, ai!y!, benzyl, tosylate group,

C(=0)-alkyl or C(=0)-Bn,

R'" = H, alkyi, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -giycoside group or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethyisilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ^; = OH, OGP', NH ₂ , N ₃ , NHGP' or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethyisilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁸ is a hydrogen atom H or a free or protected alcohol function, and

if R ¹ - R ² - H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ³ ~

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y = H, OR, N ₃ , NR'R", or SR"\

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyidipheny!silyi, or acetate group,

R\ R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in v/hich GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R- = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function, if R ¹ = R ³ = H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ² ^

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y = H, OR, N ₃ , NR'R", or SR"\

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyidipheny!silyi, or acetate group,

R\ R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in v/hich GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R- = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function, if R ² = R ³ = H, CH ₃ , CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R -

Y'

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y H, OR, N ₃ , NR'R", or SR' ' ',

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyidipheny!siiyi, or acetate group,

R\ R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in v/hich GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyidimetby!silyi, tert-butyldiphenylsilyl, or acetate group,

R- = OH, OOP', NH N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function.

[049] According to another embodiment, there is provided an gem-difluorinated C- giycopeptide compound of general formula I, or a pharmaceutically acceptable base, addition salt with an acid, hydrate or solvate thereof, for protecting isolated neurosensory precursor cell from prostaglandin E2 toxicity prior to transplantation in a subject in need thereof:

in which:

N is an integer between 1 and 5,

R ⁴ = H, AAi, or AA AA ₂ ,

R ⁵ ~ OH, AA-i, or AA AA _2j

A and AA ₂ independentiy represent amino acids with a non-polar side chain and

R ¹ , R ² , R ³ are independent groups in which two of R ¹ , R ² and R ³ are selected from H, CH ₃₎ CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ or CH(CH ₃ )CH ₂ CH ₃ and the remaining R ¹ , R ² , R ³ is

in which:

n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y" = H, OR, N ₃ , NR'R", or SR"',

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyldipheny!silyl or acetate group, R', R" independently = H, alkyi, aiiyi, benzyl tosyiate group,

C(=0)-alkyl or C(=0)-Bn,

R'" = H, alkyi, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -giycoside group or CH ₂ -GGP in which GP is a protector group selected from alkyi, benzyl, trimethylsilyl, tert- butyidimethylsiiyi, tert-butyldiphenylsilyl, or acetate group, R ⁷ = OH, OGP', NH ₂ , N.3, NHGP' or NGP'GP" in which GP' and GP" are independently selected from alkyi, benzyl, trimethylsilyl, tert- butyidimethylsiiyi, tert-butyldiphenylsilyl, or acetate group, R ⁸ is a hydrogen atom H or a free or protected alcohol function, and

if R ¹ - R ² - H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ³ =

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y - H, OR, N ₃ , NR'R", or SR'",

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyi, allyl, benzyl, tosyiate group, C(=0)-alkyl, or C(=0)-Bn, R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in v/hich GP is a protector group seiected from alkyl, benzyl, trimethyisilyl, tertbutyldimethyisilyi, iert-butyidiphenyisiiyi, or acetate group,

R ⁷ - OH, OGP, NH ₂ , N ₃ , NHGP, or NGP'GP" in which GP and GP" are independently seiected from alkyl, benzyl, trimethyisilyl, tertbutyldimethyisilyi, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function,

R ³ ~ H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y - H, OR, N ₃ , NR'R", or SR"',

where R - H, benzyl, trimethyisilyl, tert-butyidimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, ally!, benzyl, tosylate group, C(=0)~alky!, or C(=0)-Bn,

R'" = H, alkyl, or acetate group, R ⁶ is H, CH _3l CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in which GP is a protector group selected from aikyl, benzyl, trimethyisilyl, tert-butyidimethylsilyi, tert-butyldiphenylsilyl, or acetate group,

R ⁷ - OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethyisilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function, if R ² ~ R ³ = H, CH ₃ , CH(CH ₃ ) _2> CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R -

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y H, OR, N ₃ , NR'R", or SR' ' ',

where R = H, benzyl, trimethyisilyl, tert-butyidimethylsilyi, tert- butyldiphenylsilyl, or acetate group,

R\ R" independently = H, aikyl, ally!, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group, R ⁶ is H, CH _3l CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in which GP is a protector group selected from aikyl, benzyl, trimethylsilyl, tert-butyidimethylsilyi, tert-butyldiphenylsilyl, or acetate group,

R ⁷ - OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyi, benzyl, trimethylsilyl, tertbutyldimethylsilyl, terf-butyldiphenylsilyi, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function.

] The subject may be a human subject.

] The compound of formula I may be a compound of formula II:

in which: N is an integer between 1 and 5,

and

R , R ² , R ³ are independent groups in which two of R ¹ , R ² and R ^a are selected from H, CH ₃ and the remaining R , R ² and R ³ is

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y" - H, OR, N ₃ , NR'R" or SR"',

where R = H, benzyl, trimethylsiiyi, tert-butyidimethylsiiyi, tert-butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, ailyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is selected from H, CH _3> CH ₂ OH, CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsiiyi, tert- butyidimethylsiiyi, tert-butyldiphenylsilyl, or acetate group,

R ⁷ OH, OGP\ NH ₂ , N ₃ , NHGP', NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsiiyi, tert- butyidimethylsiiyi, tert-butyldiphenylsilyl or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function, and

if R ¹ - R ² - H or CH _3:

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' = H, OR, N ₃ , NR'R", or SR' where R = H, benzyl, irimetby!siiyi, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R\ R" independently = H, alkyi, aliyi, benzyl, tosylate group,

C(=0)-alk l, or

C(=0)-Bn,

R'" = H, alkyi, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, CH ₂ -OGP in which GP is a protector group selected from aikyl, benzyl, trimethylsilyl, teri-butyidimethy!siiyi, tert- butyidiphenylsilyi, or acetate group,

R ⁷ -OH, OGP', NH ₂ , N ₃ , NHGP', NGP'GP" in which GP' and GP" are independently selected from alkyi, benzyl, trimethylsilyl, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁸ is a hydrogen atom H or a free or protected alcohol function,

H o CH ₃ ,

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' - H, OR, N ₃ . NR'R", SR"\

where R = H, benzyl, trimethylsilyl, tert-butyidimethylsiiyi, tert- butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyi, allyl, Bn, tosyiate, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, or CH ₂ -OGP in which GP is a protector group selected from alkyi, benzyi, irimethy!siiyi, tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁷ = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyidimethy!siiyi, tert-butyldiphenylsilyl, or acetate group, R ⁸ is a hydrogen atom H or a free or protected alcohol function, if R ² ~ R ³ ~ H or CH ₃ ,

then R ¹ =

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' H, OR, N _3l NR'R", or SR' ' ',

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, ally!, benzyl, tosyiate group,

C(=0)-alkyl, or C(=0)-Bn,

R"' = H, alkyi, or acetate group, R ⁶ is selected from H, CH ₃ , CH ₂ QH, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimetbylsilyl , tert- butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R ⁷ -OH, OGP, NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert- butyidimethylsiiyi, tert-butyldiphenylsilyl, or acetate group, hydrogen atom or a free or protected alcohol function.

The com ound of formula 1 may be a compound of formula ill:

(111).

[053] The contacting the isolated neurosensory precursor cells may be with from about from about 0.01 mg/ml to about 5 mg/ml, or from about 1 mg/ml to about 3 mg/ml, or from about 3 mg/ml to about 5 mg/ml of the compound of formula I, formula N or formula 111.

[054] The compound of formula I, II or III may be washed away to be remove from the isolated neurosensory precursor ceil. [055] The the compound of formula I, II or III may be in contact with the isolated neurosensory precursor ceil may be contacted for at least 1 hour. The following terms are defined below.

[056] The isolated neurosensory precursor cell may be a photoreceptor precursor cell.

[057] The term « composition » as used herein is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts. Such term in relation to pharmaceutical composition or other compositions in general, is intended to encompass a product comprising the active ingredient(s) and the inert ingredient(s) that make up the carrier, as 'well as any product which results, directly or indirectly, from combination, complexation or aggregation of any two or more of the ingredients, or from dissociation of one or more of the ingredients, or from other types of reactions or interactions of one or more of the ingredients. Accordingly, the pharmaceutical compositions or other compositions in general of the present invention encompass any composition made by admixing a compound of the present invention and a pharmaceutically acceptable carrier. By "pharmaceutically acceptable" or "acceptable" it is meant the carrier, diluent or excipient must be compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.

[058] The terms "neurosensory precursor cell", are intended to mean ceils derived from human embryonic stem cells or induced pluripotent stem cells, isolated through known protocols and/or as described herein below, as well as ceils of grown in vivo, ex vivo and/or in vitro.

[059] "Aikyl", as well as other groups having the prefix "aik", such as alkoxy and alkanoyl, means carbon chains which may be linear or branched, and combinations thereof, unless the carbon chain is defined otherwise. Examples of aikyl groups include methyl, ethyl, propyl, isopropyl, butyl, sec- and tert-butyl, pentyl, hexyi, heptyl, octyi, nonyl, and the like. Where the specified number of carbon atoms permits, e.g., from C3- 10, the term alkyl also includes cycioaikyl groups, and combinations of linear or branched aikyl chains combined with cycioaikyl structures. When no number of carbon atoms is specified, C1-6 is intended. [060] "Cycloaikyl" is a subset of alky! and means a saturated carbocyclic ring having a specified number of carbon atoms. Examples of cycloaikyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and the like. A cycloaikyl group generally is monocyclic unless stated otherwise. Cycloaikyl groups are saturated unless otherwise defined.

[061] The term "alkoxy" refers to straight or branched chain alkoxides of the number of carbon atoms specified (e.g., C1-6 alkoxy), or any number within this range [i.e., methoxy (MeO-), ethoxy, isopropoxy, etc.].

[062] The term "alkylthio" refers to straight or branched chain alkyisulfides of the number of carbon atoms specified (e.g., C1-6 alkylthio), or any number within this range [i.e., metby!thio (MeS-), efhyithio, isopropy!thio, etc.].

[063] The term "alkyiamino" refers to straight or branched alkylamines of the number of carbon atoms specified (e.g., C1-6 alkyiamino), or any number within this range [i.e., methylamino, ethylamino, isopropylamino, t-butylamino, etc.].

[064] The term "aikylsuifonyl" refers to straight or branched chain aikylsulfones of the number of carbon atoms specified (e.g., C1-6 aikylsuifonyl), or any number within this range [i.e., methylsulfonyi (MeS0 ₂ ^" ), ethylsulfonyi, isopropyisuifonyl, etc.].

[065] The term "alkylsulfinyl" refers to straight or branched chain alkylsulfoxides of the number of carbon atoms specified (e.g., Ci_ ₆ alkylsulfinyl), or any number within this range [i.e., methy!sulfinyl (MeSO-), ethyisulfinyi, isopropyisulfinyi, etc.].

[066] The term "alkyloxycarbonyl" refers to straight or branched chain esters of a carboxyiic acid derivative of the present invention of the number of carbon atoms specified (e.g., Ci. ₆ alkyloxycarbonyl), or any number within this range [i.e., methyloxycarbonyi (MeOCO ^" ), ethyloxycarbonyl, or butyloxycarbonyl].

[067] "Aryl" means a mono- or polycyclic aromatic ring system containing carbon ring atoms. The preferred aryls are monocyclic or bicydic 6-10 membered aromatic ring systems. Phenyl and naphthyl are preferred aryls. The most preferred aryl is phenyl. [068] "Heterocyclyl" refer to saturated or unsaturated non-aromatic rings or ring systems containing at least one heteroatom selected from O, S and N, further including the oxidized forms of sulfur, namely SO and S0 ₂ . Examples of heterocycles include tetrahydrofuran (THF), dihydrofuran, 1 ,4-dioxane, morpholine, 1 ,4-dithiane, piperazine, piperidine, 1 ,3-dioxolane, imidazolidine, imidazoline, pyrroline, pyrrolidine, tetrahyd ropy ran, dihydropyran, oxathiolane, dithiolane, 1 ,3-dioxane, 1 ,3-dithiane, oxathiane, thiomorpholine, 2-oxopiperidin-1-yl, 2-oxopyrrolidin-1-yl, 2-oxoazetidin-1-yl, 1 ,2,4-oxadiazin-5(6H)-one-3-yl, and the like.

[069] "Heteroaryi" means an aromatic or partially aromatic heterocycie that contains at least one ring heteroatom selected from O, S and N. Heteroaryls thus include heteroaryls fused to other kinds of rings, such as aryls, cycloalkyis and heterocycles that are not aromatic. Examples of heteroaryi groups include: pyrrolyl, isoxazolyl, isothiazolyi, pyrazolyl, pyridyi, oxazoiyi, oxadiazolyl (in particular, 1 ,3,4-oxadiazol-2-yi and 1 ,2,4- oxadiazol-3-yl), thiadiazolyl, thiazolyl, imidazoiyl, triazolyl, tetrazolyl, furyl, triazinyl, thienyl, pyrimidyi, benzisoxazoiyl, benzoxazolyl, benzothiazolyl, benzothiadiazolyi, dihydrobenzofuranyl, indolinyl, pyridazinyl, indazolyl, isoindolyl, dihydrobenzothienyl, indolizinyi, cinnoiinyl, phthaiazinyi, quinazolinyl, naphthyridinyl, carbazoiyi, benzodioxoiyi, quinoxalinyl, purinyi, furazanyi, isobenzylfuranyi, benzimidazolyl, benzofuranyl, benzothienyl, quinolyl, indolyl, isoquinolyl, dibenzofuranyl, and the like. For heterocyclyl and heteroaryi groups, rings and ring systems containing from 3-15 atoms are included, forming 1-3 rings.

[070] "Halogen" refers to fluorine, chlorine, bromine and iodine. Chlorine and fluorine are generally preferred. Fluorine is most preferred when the halogens are substituted on an aikyl or alkoxy group (e.g. CF ₃ 0 and CF ₃ CH ₂ 0).

[071] Before describing the present invention in detail, a number of terms will be defined. As used herein, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[072] It is noted that terms like "preferably", "commonly", and "typically" are not utilized herein to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to highlight alternative or additional features that can or cannot be utilized in a particular embodiment of the present invention.

[073] For the purposes of describing and defining the present invention it is noted that the term "substantially" is utilized herein to represent the inherent degree of uncertainty that can be attributed to any quantitative comparison, value, measurement, or other representation. The term "substantially" is also utilized herein to represent the degree by which a quantitative representation can vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

[074] Features and advantages of the subject matter hereof will become more apparent in light of the following detailed description of selected embodiments, as illustrated in the accompanying figures. As will be realized, the subject matter disclosed and claimed is capable of modifications in various respects, all without departing from the scope of the claims. Accordingly, the drawings and the description are to be regarded as illustrative in nature, and not as restrictive and the full scope of the subject matter is set forth in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[075] Further features and advantages of the present disclosure will become apparent from the following detailed description, taken in combination with the appended drawings, in which:

[076] Fig. 1 illustrates the ex vivo model system as used to identify the present invention. (A) Schematic representation of the co-culture model system. Retinal pigment epithelium (RPE) is cultured on a polyester membrane and a neurosensory retinal expiant is placed upon it with a tissue culture insert (polytetrafluoroethylene membrane). The photoreceptor layer faces the apical surface of the RPE. Precursor ceils are placed upon the RPE surface before the retinal expiant is added to the culture. (B) A low magnification representative image of a frozen cross-section through the co-culture model system. The precursor ceils (arrowheads) reside on top of the RPE layer and underneath the retinal expiant.

[077] Fig. 2 illustrates that AAGP™ reduces the amount of prostaglandin E2 (PGE2) secreted by degenerating explants and the level of COX-2 expression. PGE2 is toxic to photoreceptor precursor cells (PRCs). (A) Rat retinal explants were cultured in explant medium with or without 4mg/ml AAGP (n=3 for each condition). Explant media was replaced after 24 hours and replenished every other day with medium not containing AAGP. After ten days, explant medium was collected and processed for PGE2 ELISA. Histograms represent the amount of PGE2 (pg/ml) present in the explant medium. (B) COX-2 expression was assessed by RT-qPCR in stressed ARPE-19 cells in the presence or absence of 4mg/mi AAGP (n=4). Histograms represent fold change in COX- 2 expression, normalized to GAPDH. (C) Cultured PRCs were treated with increasing amounts of PGE2 for 48 hours, followed by the MTT assay (n-4). The effect on PRCs' metabolic activity was plotted as a function of PGE2 concentrations.

[078] Fig. 3 illustrates that Cell survival is enhanced by pre~incubation with AAGP™. Untreated or AAGP™-treated PRCs are fluorescently labelled and placed between retinal explants and RPE for ten days (n=4). Live PRCs are separated by Fluorescence- Activated Cell Sorting and the proportion of cells surviving after 10 days of co-culture was calculated. Percent cell survival of untreated and AAGP-treated PPCs was plotted ( and for each condition the average ± SEM is represented by a thick black line.

DETAILED DESCRIPTION OF THE PREFERRED E BODIMENTS

[079] in embodiments there are disclosed an in vitro method for enhancing engraftment of neurosensory precursor cells comprising the step of:

a) contacting an isolated neurosensory precursor ceil prior to a transplantation in a subject in need thereof, with a gem-dif!uorinated C~glycopeptide compound of general formula I, or a pharmaceutically acceptable base, addition salt with an acid, hydrate or solvate thereof, and then washing the isolated neurosensory precursor ceils to remove the compound :

in which:

N is an integer between 1 and 5,

AAi and AA ₂ independently represent amino acids with a non-polar side chain and

R ¹ , R ² , R ³ are independent groups in which two of R ¹ , R ² and R ³ are selected from H, CH ₃ . CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ or CH(CH ₃ )CH ₂ CH ₃ and the remaining R\ R ² , R ³ is

in which:

n is an integer between 3 and 4,

Y, Y ^! are independent groups

in which Y, Y' = H, OR, N _3i NR'R", or SR'",

where R - H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenyl acetate group, R\ R" independently = H, alkyl, aliyi, benzyl, tosyiate group, C^QJ-aikyl or C(=0)-Bn, R"' = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -giycoside group or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyidiphenylsiiyi, or acetate group,

R ⁷ = OH, OGP', NH ₂ , N ₃ , NHGP' or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert-butyidimethy!silyi, tert-butyidiphenylsiiyi, or acetate g oup,

R ⁸ is a hydrogen atom H or a free or protected alcohol function,

and

if R ¹ - R ² ~ H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ³ =

in which: n is an integer between 3 and 4,

Y, Y ^' are independent groups

in which Y, Y' - H, OR, N ₃ , NR'R", or SR"

where R - H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R', R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn, R'" = H, alkyl, or acetate group,

R ⁶ is H, CH _3i CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert- butyidiphenylsiiyi, or acetate group,

R ⁷ = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function,

if R ¹ - R ³ - H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ² =

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' - H, OR, N ₃ , NR'R", or SR"\

where R - H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R', R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn, R'" = H, alkyl, or acetate group,

R ⁶ is H, CH _3i CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsi!y!, tert-butyldimethylsilyl, tert- butyidiphenylsiiyi, or acetate group,

R ⁷ = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, irimetby!silyi, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate g oup,

R ⁸ is a hydrogen atom H or a free or protected alcohol function,

if R ~ R ³ - H, CH ₃ , CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ¹ -

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' H, OR, N ₃ , NR'R", or SR' ' ',

where R - H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R', R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn, R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R ⁷ = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl,

tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function.

[080] In another embodiments there is disclosed an in vitro method for protecting isolated neurosensory precursor ceils from prostaglandin E2 toxicity comprising the step of:

a) contacting an isolated neurosensory precursor cells 'with a gem-dif!uorinated C~ giycopeptide compound of general formula I, or a pharmaceutically acceptable base, addition salt with an acid, hydrate or solvate thereof, and then washing the isolated neurosensory cells to remove the compound:

in which:

N is an integer between 1 and 5,

R ⁴ - H, AA-i , or AA AA ₂

R ⁵ ^ OH , AAL or AA AA ₂ ,

AA and AA ₂ independently represent amino acids with a non-polar side chain and R ¹ , R ² , R ³ are independent groups in which two of R ¹ , R ² and R ³ are selected from H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ or CH(CH ₃ )CH ₂ CH ₃ and the remaining R , R ² , R ³ is

in which:

n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' = H, OR, N ₃ , NR'R", or SR'",

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl or acetate group,

R', R" independently = H, alkyl, aliyi, benzyl, tosylate group, C(=0)-alkyl or C(=0)-Bn, R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -giycoside group or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R ⁷ = OH, OGP', NH ₂ , N ₃ , NHGP' or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R is a hydrogen atom H or a free or protected alcohol function,

and

if R ¹ - R ² ~ H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ³ =

in which: n is an integer between 3 and 4,

Y, Y ^' are independent groups

in which Y, Y' - H, OR, N ₃ , NR'R", or SR"

where R - H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, allyl, benzyl, tosyiate group, C(=0)-alkyl, or C(=0)-Bn, R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R ⁷ = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R is a hydrogen atom H or a free or protected alcohol function,

if R ¹ - R ³ - H, CH ₃ , CH ₂ Ph, CH(CH ₃ ) ₂ , CH ₂ CH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ² =

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' - H, OR, N ₃ , NR'R", or SR'",

where R - H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, allyl, benzyl, tosyiate group, C(=0)-alkyl, or C(=0)-Bn, R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R ⁷ = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alky!, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group, R is a hydrogen atom H or a free or protected alcohol function,

if R ~ R ³ - H, CH ₃ , CH(CH ₃ ) ₂ , CH ₂ eH(CH ₃ ) ₂ , or CH(CH ₃ )CH ₂ CH ₃

then R ¹ -

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' H, OR, N ₃ , NR'R", or SR' '

where R - H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn, R'" = H, alkyl, or acetate group,

R ⁶ is H, CH ₃ , CH ₂ OH, CH ₂ -glycoside group, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R ⁷ = OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tertbutyldimethylsilyl, tert-butyidiphenylsiiyi, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function

wherein the compound protects the isolated neurosensory precursor cells from prostaglandin E2 toxicity.

[081 ] Contacting may be prior to a transplantation in a subject in need thereof, for example, a human subject.

[082] In embodiments, the compound of formula I is a compound of formula II :

in which: N is an integer between 1 and 5,

and

R ¹ , R ² , R ³ are independent groups in which two of R ¹ , R ² and R ³ are selected from H, CH ₃ and the remaining R , R ² and R ³ is

in which : n is an integer between 3 and 4, Y, Y' are independent groups

in which Y, Y ^" ^ H, OR, N ₃ , NR'R" or SR"',

where R = H, benzyi, trimethyisilyi, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, allyl, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethyisilyi, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R ⁷ -OH, OGP ^! , NH ₂ , N ₃ , NHGP', NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethyisilyi, tert-butyldimethylsilyl, tert-butyldiphenylsilyl or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function,

and

if R ¹ = R ² ~ H or CH ₃ ,

then R ³ -

in which : n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' - H, OR, N ₃ , NR'R", or SR' ' ',

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyi, ally!, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyi, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, CH ₂ -OGP in which GP is a protector group selected from aikyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R ⁷ =OH, OGP', NH ₂ , N ₃ , NHGP', NGP'GP" in which GP' and GP" are independently selected from aikyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function,

if R = R ³ = H or CH ₃ ,

then R ² ™

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' - H, OR, N ₃ , NR'R", SR"

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R', R" independently = H, alkyl, ally!,

Bn, tosyiate, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, or CH ₂ -OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R ⁷ - OH, OGP\ NH ₂ , N ₃₎ NHGP', or NGP'GP" in which GP' and GP" are independently selected from alkyl, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom H or a free or protected alcohol function,

if R ² = R ³ = H or CH ₃ ,

then R ¹ -

in which: n is an integer between 3 and 4,

Y, Y' are independent groups

in which Y, Y' H, OR, N ₃ , NR'R", or SR' ' ',

where R = H, benzyl, trimethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, or acetate group,

R', R" independently = H, aikyl, aliyi, benzyl, tosylate group, C(=0)-alkyl, or C(=0)-Bn,

R'" = H, alkyl, or acetate group,

R ⁶ is selected from H, CH ₃ , CH ₂ OH, or CH ₂ ~OGP in which GP is a protector group selected from alkyl, benzyl, trimethylsilyl , tert-butyldimethylsilyl, tert- butyldiphenylsilyl, or acetate group,

R ⁷ -OH, OGP', NH ₂ , N ₃ , NHGP', or NGP'GP" in which GP' and GP" are independently selected from aikyl, benzyl, trimethylsilyl, terf-butyidimethylsiiyi, tert-butyldiphenylsilyl, or acetate group,

R ⁸ is a hydrogen atom or a free or protected alcohol function.

In an embodiment, the compound of formula I is a compound of formula III:

(ill). [084] Contacting the isolated neurosensory precursor ceils is with from about from about 0.01 mg/mi to about 5 mg/ml, or about 1 mg/ml to about 5 mg/ml, or 1 mg/ml to about 3 mg/mi, or from about 3 mg/ml to about 5 mg/ml of the compound of formula I, formula II or formula III.

[085] According to another embodiment, there is disclosed an isolated neurosensory precursor ceils prepared according to the method of the present invention.

[086] According to another embodiment, there is disclosed a method of transplanting neurosensory precursor cells in a subject in need thereof comprising the steps of :

a) transplanting an isolated neurosensory precursor cells prepared according to the method of the present invention, in the subject in need thereof.

[087] According to another embodiment, there is disclosed a method of treating a retinal degenerative disease comprising the step of :

a) transplanting an isolated neurosensory precursor ceil prepared according to the method of the present invention, in the subject in need thereof.

[088] In embodiments, the immunosuppressant drug may be daclizumab, sirolimus, tacrolimus, cyclosporine, or a combination thereof.

[089] According to another embodiment, there is disclosed a method of treating a retinal degenerative disease comprising the step of :

a) transplanting an isolated neurosensory precursor cell prepared according to the method of the present invention, in the subject in need thereof.

[090] The retinal degenerative disease may be age-related macular degeneration (AMD), retinitis pigmentosa (RP), retinal vasculitis, or sarcoidosis.

[091] According to another embodiment, there is provided a use of an isolated neurosensory precursor ceil prepared according to the method of the present invention, for transplantation to a subject in need thereof.

[092] According to another embodiment, there is provided a use of an isolated neurosensory precursor ceil prepared according to the method of the present invention, for treatment of a retinal degenerative disease in a subject in need thereof. [093] The retinal degenerative disease is age-related macular degeneration (AMD), retinitis pigmentosa (RP), retinal vasculitis, or sarcoidosis.

[094] According to another embodiment, there is provided a use of an isolated neurosensory precursor cell according to the method of the present invention, for transplantation to a subject in need thereof.

[095] According to another embodiment, there is provided an isolated neurosensory precursor cell contacted with a gem-difluorinated C-giycopeptide compound of general formula I (above), or a pharmaceutically acceptable base, addition salt with an acid, hydrate or solvate thereof. The compound of formula 1 may be a compound of formula II (as shown above). The compound of formula 1 may be a compound of formula HI (as shown above).

[096] According to another embodiment, there is provided a use of a gem-difluorinated C-giycopeptide compound of general formula I (as shown above), or a pharmaceutically acceptable base, addition salt with an acid, hydrate or solvate thereof, for enhancing engraftment of isolated neurosensory precursor ceil in a subject in need thereof.

[097] According to another embodiment, there is provided a use of a gem-difluorinated C-giycopeptide compound of general formula I (as shown above), or a pharmaceutically acceptable base, addition salt with an acid, hydrate or solvate thereof, for protecting isolated neurosensory precursor ceil from prostaglandin E2 toxicity prior to transplantation in a subject in need thereof. The formula 1 may be a compound of formula 11 (as shown above). The compound of formula I may be a compound of formula III as shown above.

[098] According to another embodiment, there is provided a gem-difluorinated C- glycopeptide compound of general formula I (as shown above), or a pharmaceutically acceptable base, addition salt with an acid, hydrate or solvate thereof, for use in enhancing engraftment of an isolated neurosensory precursor cell in a subject in need thereof. The formula I may be a compound of formula II (as shown above). The compound of formula 1 may be a compound of formula III as shown above.

[099] According to another embodiment, there is provided a gem-difluorinated C- glycopeptide compound of general formula I, or a pharmaceutically acceptable base, addition salt with an acid, hydrate or solvate thereof, for protecting isolated neurosensory precursor cell from prostaglandin E2 toxicity prior to transplantation in a subject in need thereof. The formula I may be a compound of formula II (as shown above). The compound of formula I may be a compound of formula 111 as shown above. The compound of formula I, I I or I N may be washed away to be remove from the isolated neurosensory precursor cell.

[0100]The invention includes the compounds as shown, and also includes (where possible) individual diasiereomers, enantiomers, and epimers of the compounds, and mixtures of diasiereomers and/or enantiomers thereof including racemic mixtures. Although the specific stereochemistries disclosed herein are preferred, other stereoisomers, including diasiereomers, enantiomers, epimers, and mixtures of these may also be useful. Inactive or less active diastereoisomers and enantiomers are useful for scientific studies relating to the targets and/or the mechanism of activation.

[0101 ]The compounds disclosed herein may be used in pharmaceutical compositions comprising (a) the compound(s) or pharmaceutically acceptable salts thereof, and (b) a pharmaceutically acceptable carrier. The compounds may be used in pharmaceutical compositions that include one or more other active pharmaceutical ingredients. The compounds may also be used in pharmaceutical compositions in which the compound of Formula I, Π or 111 , or a pharmaceutically acceptable salt thereof is the only active ingredient.

[0102] Compounds of structural Formula I, structural Formula I I and/or structural Formula Hi may contain one or more asymmetric centers and can thus occur as racemates and racemic mixtures, single enantiomers, diastereomeric mixtures and individual diasiereomers. The present invention is meant to comprehend all such isomeric forms of the compounds of structural Formula I, structural Formula I I and/or structural Formula IN.

[0103]Compounds of structural Formula I, structural Formula I I and/or structural Formula II I may be separated into their individual diastereoisomers by, for example, fractional crystallization from a suitable solvent, for example methanol or ethyl acetate or a mixture thereof, or via chirai chromatography using an optically active stationary phase. Absolute stereochemistry may be determined by X-ray crystallography of crystalline products or crystalline intermediates which are derivatized, if necessary, with a reagent containing an asymmetric center of known absolute configuration.

[0104] Alternatively, any stereoisomer of a compound of the general structural Formula I, structural Formula N and/or structural Formula HI may be obtained by stereospecific synthesis using optically pure starting materials or reagents of known absolute configuration.

[0105] if desired, racemic mixtures of the compounds may be separated so that the individual enantiomers are isolated. The separation can be carried out by methods well known in the art, such as the coupling of a racemic mixture of compounds to an enantiomerica!!y pure compound to form a diasfereomeric mixture, followed by separation of the individual diastereomers by standard methods, such as fractional crystallization or chromatography. The coupling reaction is often the formation of salts using an enantiomerically pure acid or base. The diasteromeric derivatives may then be converted to the pure enantiomers by cleavage of the added chiral residue. The racemic mixture of the compounds can also be separated directly by chromatographic methods utilizing chiral stationary phases, which methods are well known in the art.

[0106]Some of the compounds described herein contain oiefinic double bonds, and unless specified otherwise, are meant to include both E and Z geometric isomers.

[0107]Some of the compounds described herein may exist as tautomers, which have different points of attachment of hydrogen accompanied by one or more double bond shifts. For example, a ketone and its enol form are keto-enol tautomers. The individual tautomers as well as mixtures thereof are encompassed with compounds of the present invention.

[0108] in the compounds of generic Formula I, Formula II and/or Formula ill, the atoms may exhibit their natural isotopic abundances, or one or more of the atoms may be artificially enriched in a particular isotope having the same atomic number, but an atomic mass or mass number different from the atomic mass or mass number predominantly found in nature. The present invention is meant to include all suitable isotopic variations of the compounds of generic Formula I, Formula II and/or Formula III. For example, different isotopic forms of hydrogen (H) include protium ( ¹ H) and deuterium ( ² H). Protium is the predominant hydrogen isotope found in nature. Enriching for deuterium may afford certain therapeutic advantages, such as increasing in vivo half-life or reducing dosage requirements, or may provide a compound useful as a standard for characterization of biological samples. Isotopicaily-enriched compounds within generic Formula I, Formula II and/or Formula ill can be prepared without undue experimentation by conventional techniques well known to those skilled in the art.

Salts and formulations

[0109] it will be understood that, as used herein, references to the compounds of structural Formula I, Formula II and/or Formula 111 are meant to also include the pharmaceutically acceptable salts, and also salts that are not pharmaceutically acceptable when they are used as precursors to the free compounds or their pharmaceutically acceptable salts or in other synthetic manipulations. The term "pharmaceutically acceptable salt" refers to salts prepared from pharmaceutically acceptable non-toxic bases or acids including inorganic or organic bases and inorganic or organic acids. Salts of basic compounds encompassed within the term "pharmaceutically acceptable salt" refer to non-toxic salts of the compounds of this invention which are generally prepared by reacting the free base with a suitable organic or inorganic acid. Representative salts of basic compounds of the present invention include, but are not limited to, the following: acetate, benzenesulfonate, benzoate, bicarbonate, bisulfate, bitartrate, borate, bromide, camsyiate, carbonate, chloride, clavuianate, citrate, edetate, edisylate, estoiate, esylate, fu ma rate, gluceptate, gluconate, glutamate, hexylreso rein ate, hydrobromide, hydrochloride, hydroxynaphthoate, iodide, isothionate, lactate, lactobionate, laurate, malate, maleate, mandeiate, mesylate, methyibromide, methylnitrate, methylsulfate, mucate, napsyiate, nitrate, N-methylglucamine ammonium salt, oleate, oxalate, pamoate (embonate), palmitate, pantothenate, phosphate/diphosphate, poiygalacturonate, salicylate, stearate, sulfate, subacetate, succinate, tannate, tartrate, teociate, tosylate, triethiodide and valerate. Furthermore, where the compounds of the invention carry an acidic moiety, suitable pharmaceutically acceptable salts thereof include, but are not limited to, salts derived from inorganic bases including aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic, mangamous, potassium, sodium, zinc, and the like. Particularly preferred are the ammonium, calcium, magnesium, potassium, and sodium salts. Salts derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary, and tertiary amines, cyclic amines, and basic ion- exchange resins, such as arginine, betaine, caffeine, choline, N,N- dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanoiamine, ethylenediamine, N-ethylmorphoiine, N-ethylpiperidine, glucamine, glucosamine, histidine, isopropyiamine, lysine, methylglucamine, morpholine, piperazine, piperidine, poiyamine resins, procaine, purines, theobromine, triethyiamine, trimethylamine, tripropylamine, tromethamine, and the like.

[0110] Also, in the case of a carboxylic acid (-COOH) or alcohol group being present in the compounds of the present invention, pharmaceutically acceptable esters of carboxylic acid derivatives, such as methyl, ethyl, or pivaioyioxymethyl, or acyi derivatives of alcohols, such as acetyl, pivaloyi, benzoyl, and aminoacyi, can be employed. Included are those esters and acyl groups known in the art for modifying the solubility or hydrolysis characteristics for use as sustained-release or prodrug formulations.

[0111] Solvates, in particular hydrates, of the compounds of structural Formula I, Formula II and/or Formula HI are included in the present invention as well.

[0112] According to an embodiment, the compounds of structural Formula I, Formula II and/or Formula IN may be included in various formulations for use as medicaments.

[0113] Aqueous suspensions contain the active material in admixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients are suspending agents, for example sodium carboxymethyl-cellulose, methylcellulose, hydroxypropyimefhy-ceilulose, sodium alginate, polyvinyl-pyrroiidone, gum tragacanth and gum acacia; dispersing or wetting agents may be a naturally-occurring phosphatide, for example lecithin, or condensation products of an aikylene oxide with fatty acids, for example poiyoxyethylene stearate, or condensation products of ethylene oxide with long chain aliphatic alcohols, for example heptadecaethylene-oxycetanol, or condensation products of ethylene oxide with partial esters derived from fatty acids and a hexitoi such as poiyoxyethylene sorbitol monooleate, or condensation products of ethylene oxide with partial esters derived from fatty acids and hexitoi anhydrides, for example polyethylene sorbitan monooleate. The aqueous suspensions may also contain one or more preservatives, for example ethyl, or n-propyi, p-hydroxybenzoate, one or more coloring agents, one or more flavoring agents, and one or more sweetening agents, such as sucrose, saccharin or aspartame.

[0114]Oiiy suspensions may be formulated by suspending the active ingredient in a vegetable oil, for example arachis oil, olive oil, sesame oil or coconut oil, or in mineral oil such as liquid paraffin. The oily suspensions may contain a thickening agent, for example beeswax, hard paraffin or cetyl alcohol. Sweetening agents such as those set forth above, and flavoring agents may be added to provide a palatable oral preparation. These compositions may be preserved by the addition of an anti-oxidant such as ascorbic acid.

[0115]Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water provide the active ingredient in admixture with a dispersing or wetting agent, suspending agent and one or more preservatives. Suitable dispersing or wetting agents and suspending agents are exemplified by those already mentioned above. Additional excipients, for example sweetening, flavoring and coloring agents, may also be present.

[0116]The pharmaceutical compositions of the invention may also be in the form of an oil-in-water emulsion. The oily phase may be a vegetable oil, for example olive oil or arachis oil, or a mineral oil, for example liquid paraffin or mixtures of these. Suitable emulsifying agents may be naturally-occurring phosphatides, for example soy bean, lecithin, and esters or partial esters derived from fatty acids and hexitol anhydrides, for example sorbitan monooleate, and condensation products of the the partial esters with ethylene oxide, for example poiyoxyethyiene sorbitan monooleate. The emulsions may also contain sweetening and flavouring agents.

[0117]The pharmaceutical compositions may be in the form of a sterile injectable aqueous or oieagenous suspension. This suspension may be formulated according to the known art using those suitable dispersing or wetting agents and suspending agents which have been mentioned above. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally-acceptable diluent or solvent, for example as a solution in 1 ,3-butane dioi. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution, in addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose any bland fixed oil may be employed including synthetic mono- or digiycerides. in addition, fatty acids such as oleic acid find use in the preparation of injectables.

[0118] According to an embodiment, the cells are isolated using methods known in the art for their preparation. For example, the cells may be isolated from donors using mixtures of enzymes such as Coilagenase I and Coliagenase II, Thermolysin, non- clostridial neutral protease, or other enzymes being used for such purpose. The isolated ceils may then be cultured under normal tissue culture conditions in standard tissue culture flasks.

[0119] According to an embodiment, the neurosensory precursor cells may be treated with a gem-dif!uorinated C-glycopeptide compound of general formula I - preferably, the compound of Formula II, and most preferably the compound of formula 111 in concentrations varying from about 0.01 mg/m! to about 5 mg/ml; or from about 0.1 mg/ml to about 5 mg/ml; or from about 0.5 mg/ml to about 5 mg/ml; or from about 1 mg/ml to about 5 mg/ml; or from about 3 mg/ml to about 5 mg/ml; or from about 0.01 mg/ml to about 3 mg/ml, or from about 0.1 mg/ml to about 3 mg/ml, or from about 0.5 mg/ml to about 3 mg/ml, or from about 1 mg/ml to about 3 mg/ml, or from about 0.01 mg/ml to about 1 mg/ml; or from about 0.1 mg/ml to about 1 mg/ml; or from about 0.5 mg/ml to about 1 mg/ml; or from about 0.01 mg/ml to about 0.5 mg/ml; or from about 0.1 mg/ml to about 0.5 mg/ml; or from about 0.01 mg/ml to about 0.1 mg/ml; or about 3 mg/ml. According to embodiments, the amounts above are considered to be therapeutically effective amounts for the purpose of the present inventions.

[0120] According to another embodiment, the ceils are contacted with the gem- difluorinated C-glycopeptide compound for a time sufficient to effect improvements on ceil viability and survival rate. According to embodiments, the time sufficient may be from about 12 hours to 120 hours, or from about 12 hours to about 96 hours, or from about 12 hours to about 72 hours, or from about 12 hours to about 48 hours, or from about 12 hours to about 24 hours, or about 120 hours, or about 96 hours, or about 72 hours, or about 48 hours, or about 24 hours, or about 12 hours, or about 10 hours, or about 8 hours, or about 6 hours, or about 4 hours, or about 2 hours, or about 1 hour. In embodiments, the wherein the isolated neurosensory precursor cell is contacted with the compound for 1 hour, 55 mins, 50 mins, 45 mins, 40 mins, 35 mins, 30 mins, 25 mins, 20 mins, 15 mins, 10 mins, 5 mins, 4 mins, 3 mins, 2 mins, 1 mins, 45 sees, or 30 sees, or at least 1 hour, or at least 55 mins, or at least 50 mins, or at least 45 mins, or at least 40 mins, or at least 35 mins, or at least 30 mins, or at least 25 mins, or at least 20 mins, or at least 15 mins, or at least 10 mins, or at least 5 mins, or at least 4 mins, or at least 3 mins, or at least 2 mins, or at least 1 mins, or at least 45 sees, or at least 30 sees.

[0121] In another embodiment there is disclosed a cell preparation prepared according to the method of the present invention, in a pharmaceutically acceptable carrier. According to an embodiment, the cell preparation may be used for the preparation of a medicament for a ceil transplantation. According to another embodiment, the cell preparation may be used for a cell transplantation.

[0122] In another embodiment, there is disclosed a method of transplantation comprising transplanting a ceil preparation of the present invention to a subject in need thereof. The subject may be a mammal, and preferably a human.

[0123]The present invention will be more readily understood by referring to the following examples which are given to illustrate the invention rather than to limit its scope.

EXAMPLE 1

[0124]To identify the key factors that inhibit NPC integration into diseased tissue, an ex vivo tissue culture system has been developed to enable the identification of factors that reduce and factors that enhance cell survival and functional integration (Yanai et ai., 2015). The ex vivo system mimics the subretinal space in a regulated environment that includes a neurosensory retinal expiant placed on top of human embryonic stem ceils (hESC) derived retinal pigment epithelium (RPE). NPCs (such as human photoreceptor precursor ceils; PRCs, Yanai et al., 2013) can then be placed within the model in a more controlled environment. Thus the role of adverse factors such as nutritional deficits and toxic metabolites can be studied in isolation from other hostile effects such as surgical trauma and immune rejection, it is hypothesized that toxic metabolites, such as PGE2, are major adverse factors during tissue transplantation in necrotic neurodegeneration of the retina. Furthermore, AAGP™ is selected as a potential protective agent, and its ability to prevent PGE2 toxic effects is examined. AAGP™ is a small, stable, synthetic analog of anti-freeze protein (AFP) which has been shown to protect cells for example, against exposure to extreme temperatures and ultraviolet irradiation (US Patent publication No. US2009031 1203).

|0125]Now referring to Fig. 1 , within the ex vivo system, rat neurosensory retinal explants are incubated upon human embryonic stem cells (hESC) derived retinal pigment epithelium (RPE). Neurosensory retina was obtained from the S334ter-4 model of retinal degeneration (Chen et al, 1995) and cultured within the system for 10 days (for detailed experimental design see Yanai et al., 2015). Rodent retinal tissue collection was carried out with approval of the Animal Care Committee at the University of British Columbia and in accordance with the Association for Research in Vision and Ophthalmology Statement for the Use of Animals in Ophthalmic and Vision Research. Throughout the present study, AAGP™ was used at 4 mg/ml, after it was confirmed it was not toxic to PPCs at this concentration (unpublished data).

[0126] Firstly, the amount of PGE2 produced is determined within the ex vivo system under normal culture conditions and after media is supplemented with 4 mg/ml AAGP for the first 24 hours of co-culture. Three equal-sized retinal quadrants, measuring ~10mm ² each, and are analyzed for each condition. Explant media are collected at the end of 10 days and assessed for concentration of PGE2 by enzyme-linked immunosorbent assay (ELISA; R&D Systems). PGE2 induced reduction in metabolic activity, contributing to cell death, is assessed in PPCs cultured in isolation using a Thiazoiyi Blue Tetrazoiium Bromide (MTT) assay (Sigma).

[0127]To determine whether AAGP™ inhibits COX-2 expression, ARPE-19 ceils (Dunn et al., 1996) are treated with 17 ng/ml Interleukin 1 β (IL-Ι β; Sigma; Lukiw et al., 2008 ) for 8 hours and then added 5mM ATP for 1 hour to further induce cell stress (Sigma; Mehta et al., 2001 ). ARPE-19 is a human retinal pigment epithelia (RPE) ceil line spontaneously arising from a primary culture of RPE ceils from a male donor. These ceils have many morphological and some functional similarities with authentic RPE. Experiments are conducted either in the presence or absence of 4 mg/ml AAGP™. COX-2 expression is assessed using Reverse Transcription Quantitative Polymerase Chain Reaction (RT-qPCR) with the TaqMan® primer/probe system, Fast Advanced Master Mix and the ViiA™ 7 Real Time PGR system (Applied Biosystems).

[0128]To determine whether AAGP™ improves PPG survival in the ex vivo system, PPG eel! viability is assessed with and without pre-treating cell grafts with AAGP™ for 24 hours prior to inclusion within the ex vivo system. PRCs are labelled with 20 μΜ CeilTrace™ Far Red DDAO-SE (Life Technologies). DDAO-SE is a fixable, far-red fluorescent tracer for long-term cell labeling. The tracer is colorless and non-fluorescent until its acetate groups are cleaved by intracellular esterases to yield highly fluorescent products. DDAO-SE forms a strong covalent attachment to primary amines on proteins and other biomoiecules and is therefore not likely to transfer to other types of ceils in the co-culture. In each experiment (n=4), between 2 and 4 retinal explants are used for each condition ('technical repeats'). About 350,000 labeled PRCs are used in each technical repeat. After 10 days, the components of the co-culture system are enzymatically dissociated into single cell suspensions and the number of viable PRCs is assessed by Fluorescence-Activated Cell Sorting (FACS; influx Sorter; BD Biosciences).

[0129] For statistical analyses an unpaired Student's t-test is performed. P values of less than 0.05 are considered significant.

[0130]The results demonstrate that following 10 days of co-culture, the explant medium contained -20 pg/ml of PGE2, and when AAGP™ is present for the first day, the amount of PGE2 decreased to -7.5 pg/ml (n=3; p<0.05; Fig. 2A).

[0131JA plausible reason for the reduced level of PGE2 in the presence of AAGP™ is that COX-2 levels are downreguiated by this compound. COX-2 is induced by inflammatory stimuli and its expression is likely chronic in the explant system, making it difficult to detect small changes in expression levels. Therefore, COX-2 expression is assessed in cultured cells, responding to an acute stress, where the effect is maximized. COX-2 downreguiation is confirmed in an ARPE-19 cell stress assay using IL-1 β followed by ATP. COX-2 expression is evident in stressed ceils but this expression declined by at least 13.3±4.5 fold, to negligible levels, in the presence of AAGP™ (n=4; Figure 2B). To examine whether PGE2 is toxic to ceils, PRCs are cultured for 48 hours in retinal differentiation medium supplemented with increasing amounts of PGE2 (up to 50μΜ) and analyzed cells survival by the MTT assay (n=4). Cell survival is reduced by up to 44% (Fig. 2C), confirming PGE2 toxicity.

[0132] Finally, the viability of PRCs in the ex vivo system is tested. Untreated PRCs or PRCs pre-treated for 24 hours with 4 mg/ml AAGP™ are labelled with a fluorescent live cell tracer and -350,000 PPCs are placed in-between the explant and RPE. Ten days later, the co-cultured components were dissociated into single cells and viable PPCs (labeled red) were separated by Fluorescence activated cell sorting (FACS, Fig. 3). The proportion of live ceils remaining after 10 days of co-culture is calculated. An almost 3- fold increase in average cell viability is obtained when PPCs are pre-treated with AAGP™ for 24 hours before "transplantation" (49% vs. 18%; p<0.05).

[0133] Altogether the results presented in this study indicate that NPCs, such as PPCs, transplanted into neurological tissue may, in part, die as a result from exposure to PGE2 released from host necrotic tissue, such necrosis is a cause of retinal degenerations such as retinal detachment. Targeting toxic by-products such as PGE2 therefore appears to surprisingly and unexpectedly be a valid option to improve survival of transplanted precursor cells. The data presented here suggests that AAGP™ may have a role in inhibiting PGE2 production in necrotic tissue ex vivo.

[0134]The ex vivo system presented herein appears to be an appropriate screening method to identify valid therapeutics to move into more labor intensive in vivo studies. These results also suggest that other inhibitors of COX2, such as non-steroidal antiinflammatory drugs, may likewise enhance survival of transplanted NPCs during cell transplantation experiments.

[0135] While preferred embodiments have been described above and illustrated in the accompanying drawings, it will be evident to those skilled in the art that modifications may be made without departing from this disclosure. Such modifications are considered as possible variants comprised in the scope of the disclosure.

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