OLIGONUCLEOTIDES AND METHODS OF USE

Background

[1 ] The present application relates to oligonucleotides that reduce expression of islet amyloid polypeptide. The oligonucleotides are useful in the study and treatment of diabetes.

[2] Type 2 (non-insulin dependent) diabetes mellitus is characterized by the presence of fasting hyperglycemia that increases in severity as the disease progresses. Islet amyloid deposits are a characteristic pathology of the pancreas in type 2 diabetics and likely contribute to the progressive loss of insulin secretion in the disease by destroying islet β-cells. Islet amyloid is composed primarily of the β-cell peptide islet amyloid polypeptide (IAPP or amylin), a 37 amino acid peptide that is co-secreted with insulin. In addition, the amyloid deposits contain heparan sulfate proteoglycan perlecan and a partially processed NH -extended form of the IAPP precursor, pro-IAPP.

[3] US Patent No. 6,562,836 discloses methods and compositions for inhibiting, preventing and treating amyloid deposition, e.g., in pancreatic islets wherein the amyloidotic deposits to be treated are, e.g., islet amyloid polypeptide (IAPP)-associated amyloid deposits. The methods of the invention involve administering to a subject a therapeutic compound which inhibits, reduces or disrupts amyloid deposits, e.g., IAPP-associated amyloid deposits. The therapeutic compounds are small molecules that interact with IAPP.

[4] US Patent Publication 2002/0119926 Al discloses methods and compositions for inhibiting amyloid fibril formation for delaying or preventing progression of Alzheimer's disease and diabetes. The methods of the invention involve administration of short peptides that inhibit or disrupt aggregation of amyloid deposits. The therapeutic compounds are small peptides that interact with IAPP.

Summary of the Invention

[5] The present invention provides oligonucleotide compositions that interact with mRNA encoding IAPP and result in reduced expression of the peptide precursor, pro- IAPP. It will be appreciated that the actual mRNA encodes the entire precursor pre- pro-IAPP, and that the term "mRNA encoding IAPP" is used for simplicity. In particular, the oligonucleotides may be siRNA oligonucleotides comprising portions that correspond to the sequence of IAPP. Corresponding single stranded antisense oligodeoxynucleotides may also be employed in the invention.

[6] The present invention also provides in vitro cell cultures comprising pancreatic islet cells, for example human islet cells, wherein the islet cells are transfected with an oligonucleotide that interacts with mRNA encoding IAPP and result in reduced expression of the peptide precursor, pro-IAPP. This results in reduced amyloid plaque deposition in the cultured cells, and this provides a method of improving the quality of

an in vitro islet cell.

[7] The present invention also provides an in vitro method for preparing islet cells, for example human islet cells, for transplantation. In accordance with this aspect of the invention, islet cells are transfected prior to transplantation with an oligonucleotide that interacts with mRNA encoding IAPP and results in reduced expression of the peptide precursor, pro-IAPP.

[8] The present invention also provides a method for treatment of type I diabetic patients , particularly human patients, following islet cell transplantation using oligonucleotide composition that interact with mRNA encoding IAPP and result in reduced expression of the peptide precursor, pro-IAPP.

[9] The present invention further provides a method for treatment of type II diabetes in patients, particularly human patients, suffering from type 2 diabetes comprising administering an oligonucleotide composition that interacts with mRNA encoding IAPP and results in reduced expression of the peptide precursor, pro-IAPP.

Brief Description of the Drawings

[10] Fig. 1 shows the effect of siRNA-mediated suppression of human proIAPP on amyloid-induced cell death in COS-I cells.

[11] Fig. 2 shows the effect of siRNA-mediated suppression of human proIAPP on survival of human islets in culture.

[12] Figs. 3 A and B show that siRNA-mediated suppression of human proIAPP increases insulin content and glucose-stimulated insulin secretion in cultured human islets.

Detailed Description of the Invention

[13] Oligonucleotide Compositions

[14] The present invention provides oligonucleotide compositions that interact with mRNA encoding IAPP and result in reduced expression of the peptide precursor, proIAPP. In particular, the oligonucleotides may be siRNA oligonucleotides comprising portions that correspond to the sequence of IAPP. Corresponding single stranded antisense oligodeoxynucleotides may also be employed in the invention.

[15] The oligonucleotides in accordance with this invention comprise compounds from about 8 to about 80 nucleobases (i.e. from about 8 to about 80 linked nucleosides). In preferred embodiments, the oligonucleotides include sequence specific regions targeting the mRNA encoding IAPP each having a length of 8 to 25 nucleobases.

[16] The nucleic acid sequence for human pro-IAPP is known from GenBank sequence

NM_000415 to be as set forth in SEQ. ID NO:. 1

[17] DNA oligonucleotide pairs have been prepared based on three subsequences within this structure (bases 158-175, 298-316 and 375-393) to produce siRNA upon transcription. Oligonucleotides pairs having sequences as follows, with the underlined portions indicating the sequence specific regions of the oligonucleotide, were prepared for cloning into double-stranded p-Super plasmid. It will be appreciated that the non-

sequence specific regions in these pairs could have other structures, and that only one of the species will be transcribed in the plasmid.

Pair l :

sense

5'- GATCCCC GTATTTCTCATTGTGCTCT TTCAAGAGA

AGAGCACAATGAGAAATAC TTTTTGGAAA-3 ¹ SEQ ID NO: 2

antisense

5 ¹ - AGCTTTTCCAAAAA GTATTTCTCATTGTGCTCT TCTCTTGAA

AGAGCACAATGAGAAATAC GGG-3 ¹ SEQ ID NO: 3

Pair 2

sense

5'- GATCCCC CAACTTTGGTGCCATTCTC TTCAAGAGA

GAGAATGGCACCAAAGTTG TTTTTGGAAA-3 ¹ SEQ ID NO: 4

antisense

5'- AGCTTTTCCAAAAA CAACTTTGGTGCCATTCTC TCTCTTGAA

GAGAATGGCACCAAAGTTG GGG-3 ¹ SEQ ID NO: 5

Pair 3:

sense

5'- GATCCCC AGAGAGAGCCACTGAATTA TTCAAGAGA

TAATTCAGTGGCTCTCTCT TTTTTGGAAA-3 ¹ SEQ ID NO: 6

antisense

5'- AGCTTTTCCAAAAA AGAGAGAGCCACTGAATTA TCTCTTGAA

TAATTCAGTGGCTCTCTCT GOG'S' SEQ ID NO: 7.

In these sequences, the underlined portions are the sequence specific regions of the siRNA molecules.

[18] As described in the examples below, these siRNA oligonucleotide pairs are effective to suppress synthesis of proIAPP. As used in the specification and claims of this application, the term 'suppress' as applied to the production of proteins, for example proIAPP, refers to a reduction in the amount of protein in a cell. In the case of proIAPP, reduction in the amount of protein can be evaluated based on the production of IAPP or by direct measurements. Suppression does not require complete elimination of protein expression.

[19] The antisense sequence specific portions of these siRNA pairs can also be used for conventional antisense treatment to suppress proIAPP. These sequences are:

AGAGCACAATGAGAAATAC SEQ ID NO: 8

GAGAATGGCACCAAAGTTG SEQ ID NO: 9, and

TAATTCAGTGGCTCTCTCT SEQ ID NO: 10.

[20] As will be appreciated by persons skilled in the art, these oligonucleotides or other oligonucleotides targeting the IAPP mRNA and suppressing synthesis of proIAPP can be modified to enhance stability of the oligonucleotides, particularly in vivo. For example, the oligonucleotides can have one or more modified internucleoside linkages. Modified oligonucleotide backbones containing a phosphorus atom therein include, for example, phosphorothioates, chiral phosphoro-thioates, phosphoro-dithioates, phosphotri-esters, aminoalkyl — phosphotri-esters, methyl and other alkyl phospho-nates including 3'-alkylene phosphonates, 5'-alkylene phosphonates and chiral phospho-nates, phosphinates, phosphoramidates including 3 '-amino phos- phoramidate and amino-alkyl-phosphoramidates, thionophosphoramidates, thiono-alkyl-phos-phonates, thiono-alkyl-phosphotriesters, phosphonoacetate and thio- phosphonoacetate (see Sheehan et ah, Nucleic Acids Research, 2003, 31(14), 4109-4118 and Dellinger et ah, J. Am. Chem. Soc, 2003, 125, 940-950), seleno-phos-phates and borano-phosphates having normal 3'-5' linkages, 2'-5' linked analogs of these, and those having inverted polarity wherein one or more inter- nucleotide linkages is a 3' to 3', 5' to 5' or 2' to 2' linkage. Oligonucleotides having inverted polarity comprise a single 3' to 3' linkage at the 3'-most internucleotide

linkage, i.e., a single inverted nucleoside residue which may be abasic (the nucleobase is missing or has a hydroxyl group in place thereof). Various salts, mixed salts and free acid forms are also included.

[21 ] N3'-P5'-phosphoramidates have been reported to exhibit both a high affinity towards a complementary RNA strand and nuclease resistance (Gryaznov et ah, J. Am. Chem. Soc, 1994, 116, 3143-3144). N3'-P5'-phosphoramidates have been studied with some success in vivo to specifically down regulate the expression of the c-myc gene (Skorski et ah, Proc. Natl. Acad. ScI, 1997, 94, 3966-3971; and Faira et ah, Nat. Biotechnoh, 2001, 19, 40-44).

[22] Representative United States patents that teach the preparation of the above phosphorus-containing linkages include, but are not limited to, U.S.: 3,687,808; 4,469,863; 4,476,301; 5,023,243; 5,177,196; 5,188,897; 5,264,423; 5,276,019; 5,278,302; 5,286,717; 5,321,131; 5,399,676; 5,405,939; 5,453,496; 5,455,233; 5,466,677; 5,476,925; 5,519,126; 5,536,821; 5,541,306; 5,550,111; 5,563,253; 5,571,799; 5,587,361; 5,194,599; 5,565,555; 5,527,899; 5,721,218; 5,672,697 and 5,625,050.

[23] In some embodiments of the invention, oligomeric compounds may have one or more phosphorothioate and/or heteroatom internucleoside linkages, in particular -CH - NH-O-CH ₂ -, -CH ₂ -N(CH ₃ )-O-CH ₂ - (known as a methylene (methylimino) or MMI backbone), -CH ₂ -O-N(CH ₃ )-CH ₂ -, -CH ₂ -N(CH ₃ )-N(CH ₃ )-CH ₂ - and -O-N(CH ₃ )-CH ₂ - CH 2 - (wherein the native phosphodiester internucleotide linkage is represented as

-O-P(-O)(OH)-O-CH -). The MMI type internucleoside linkages are disclosed in the above referenced U.S. patent 5,489,677. Amide internucleoside linkages are disclosed in U.S. Patent 5,602,240.

[24] Some oligonucleotide backbones that do not include a phosphorus atom therein have backbones that are formed by short chain alkyl or cycloalkyl internucleoside linkages, mixed heteroatom and alkyl or cycloalkyl internucleoside linkages, or one or more short chain heteroatomic or heterocyclic internucleoside linkages. These include those having morpholino linkages (formed in part from the sugar portion of a nucleoside); siloxane backbones; sulfide, sulfoxide and sulfone backbones; formacetyl and thioformacetyl backbones; methylene formacetyl and thioformacetyl backbones; riboaceryl backbones; alkene containing backbones; sulfamate backbones; methyleneimino and methylenehydrazino backbones; sulfonate and sulfonamide backbones; amide backbones; and others having mixed N, O, S and CH component parts.

[25] Representative United States patents that teach the preparation of the above oligonucleosides include, but are not limited to, U.S.: 5,034,506; 5,166,315; 5,185,444; 5,214,134; 5,216,141; 5,235,033; 5,264,562; 5,264,564; 5,405,938; 5,434,257; 5,466,677; 5,470,967; 5,489,677; 5,541,307; 5,561,225; 5,596,086; 5,602,240;

5,610,289; 5,602,240; 5,608,046; 5,610,289; 5,618,704; 5,623,070; 5,663,312; 5,633,360; 5,677,437; 5,792,608; 5,646,269 and 5,677,439. [26] Oligomeric compounds may also contain one or more substituted sugar moieties.

Suitable compounds can comprise one of the following at the 2' position: OH; F; O-, S- , or N-alkyl; O-, S-, or N-alkenyl; O-, S- or N-alkynyl; or O-alkyl-0-alkyl, wherein the alkyl, alkenyl and alkynyl may be substituted or unsubstituted C to C alkyl or C to C 10 alkenyl and alkynyl. Also suitable are O((CH 2 )n O)m CH3 , O(CH2 )n OCH3 , O(CH2 )n

NH 2 , O(CH 2 ) n CH 3 , O(CH 2 ) π ONH 2 , and O(CH 2 ) n ON((CH 2 ) n CH 3 ) 2 , where n and m are from 1 to about 10. Other oligonucleotides comprise one of the following at the 2' position: C to C ₁ lower alkyl, substituted lower alkyl, alkenyl, alkynyl, alkaryl, aralkyl, O-alkaryl or O-aralkyl, SH, SCH ₃ , OCN, Cl, Br, CN, CF ₃ , OCF ₃ , SOCH ₃ , SO ₂ CH , ONO ₂ , NO ₂ , N , NH , heterocycloalkyl, heterocycloalkaryl, aminoalkylamino, poly-alkylamino, substituted silyl, an RNA cleaving group, a reporter group, an in- tercalator, a group for improving the pharmacokinetic properties of an oligonucleotide, or a group for improving the pharmacodynamic properties of an oligonucleotide, and other substituents having similar properties. One modification includes 2'-methoxyethoxy (2'-0-CH ₂ CH ₂ OCH ₃ , also known as 2'-O-(2-methoxyethyl) or 2'-MOE) (Martin et al, HeIv. Chim. Acta, 1995, 78, 486-504), i.e., an alkoxyalkoxy group. A further modification includes 2'-dimethylaminooxyethoxy, i.e., a 0(CH ) ON(CH ) group, also known as 2'-DMAOE, as described in examples hereinbelow, and 2'-dimethylamino-ethoxyethoxy (also known in the art as 2'-O-dimethyl-amino-ethoxy-ethyl or 2'-DMAEOE), i.e.,

2'-0-(CH ₂ ) ₂ -0-(CH ₂ ) ₂ -N(CH ₃ ) ₂ .

[27] Other modifications include 2'-methoxy (2'-0-CH ₃ ), 2'-aminopropoxy (2'-OCH ₂ CH

2 CH 2 NH 2 )', 2'-ally ^J l ( ^v 2'-CH 2 -CH=CH 2 ) ^y , 2'-0-ally ^J l ( ^V 2'-0-CH 2 -CH=CH 2 ) ^J and 2'-fluoro ²

(2'-F). The 2'-modification may be in the arabino (up) position or ribo (down) position. One 2'-arabino modification is 2'-F. Similar modifications may also be made at other positions on the oligonucleotide, particularly the 3' position of the sugar on the 3' terminal nucleotide or in 2'-5* linked oligonucleotides and the 5' position of 5' terminal nucleotide. Antisense compounds may also have sugar mimetics such as cyclobutyl moieties in place of the pentofuranosyl sugar. Representative United States patents that teach the preparation of such modified sugar structures include, but are not limited to, U.S.: 4,981,957; 5,118,800; 5,319,080; 5,359,044; 5,393,878; 5,446,137; 5,466,786; 5,514,785; 5,519,134; 5,567,811; 5,576,427; 5,591,722; 5,597,909; 5,610,300; 5,627,053; 5,639,873; 5,646,265; 5,658,873; 5,670,633; 5,792,747; 5,700,920; and, 6,147,200.

[28] In vitro Cell Cultures and Methods of Use

[29] The oligonucleotide compositions of the invention are useful in making in vitro cell cultures comprising pancreatic islet cells, for example human islet cells, that exhibit

suppression of proIAPP and are thus less prone to formation of amyloid deposits. The islet cells of the invention are transfected with an oligonucleotide that interacts with mRNA encoding IAPP and results in suppression of the peptide precursor, pro-IAPP. This results in reduced amyloid plaque deposition in the cultured cells.

[30] Islet cell cultures, for example for use as a source for transplanted materials are known, and are described in for example in Beattie, G.M. et al. 2002. A novel approach to increase human islet cell mass while preserving beta-cell function. Diabetes. 51 :3435-3439.; Beattie, G.M., Hayek, A., and Levine, F. 2000. Growth and genetic modification of human beta#cells and beta-cell precursors. Genet. Eng. 22:99-120. and Hayek, A., and Beattie, G.M. 2002. Alternatives to unmodified human islets for transplantation. Curr. Diab. Rep. 2:371-376, which publications are incorporated herein by reference.

[31] The cells in the islet cell cultures of the invention are mammalian cells, such as human, primate, rodent, rabbit, ovine, porcine, bovine, feline or canine cells. The cells of the invention are typically from a donor who generally does not have the relevant disease. In one embodiment the cells are from the patient. The cells may be taken from the patient to increase their numbers in vitro and/or the cells may be treated therapeutically in some manner before administering them back to the patient. The cells can be obtained from the donor or patient by standard techniques.

[32] Before being cultured the cells are generally further purified, for example using collagenase dissociation and/or density gradient centrifugation techniques or cell sorting techniques.

[33] The cells are cultured in order allow them to recover after the isolation procedure, to increase their numbers before transplantation, and to allow transfection with the oligonucleotide of the invention to be done. Typically cells are cultured for from 12 to 150 hours, for example from 24 to 100 hours, before transplantation. Generally the cells are cultured at from 2O ⁰ C to 45°C, for example 30°C to 40°C, preferably 35°C to 37°C. Generally the pH of the culture is from 6.6 to 8.0, preferably 7 to 7.6 or 7.2 to 7.4.

[34] Transfection of islet cells in vitro can be accomplished through any known means including without limitation electroporation, liposome carriers and viral carriers. Welsh et al, Biomed Biochim Acta. 1990;49(l 2): 1157-64 describes a method for liposome mediated in vitro transfection of pancreatic islet cells. Saldeen et al, Diabetes. 1996 Sep;45(9): 1197-203. describes gene transfer to dispersed human pancreatic islet cells in vitro using adenovirus-polylysine/DNA complexes or polycationic liposomes. See also, Lakey et al., Cell Transplantation, 2001, vol. 10, no. 8, pp. 697-708. Other methods for delivery of siRNA include:

[35] Viral delivery of siRNA

[36] Other viral vectors described for gene therapy

[37] Non- viral delivery of siRNA

[38] Surgical delivery of RNAi into islets and described in Bradley S.P. et al. Successful incorporation of short-interfering RNA into islet cells by in situ perfusion. Transplant Proc. 2005 Jan-Feb;37(l):233-6.

[39] Transplantation of islet cells transfected with the oligonucleotides of the invention can be achieved using methods known in the art. For example, islet cells can be transplanted by means of a percutaneous transhepatic portal embolization as described in Shapiro, A.M. et al. 2000. Islet transplantation in seven patients with type 1 diabetes mellitus using a glucocorticoid-free immunosuppressive regimen. N. Engl. J. Med. 343:230-238. which is incorporated herein by reference. Immunosuppressive therapy in combination with transplantation may be appropriate where the transplant is from a heterologous source.

[40] In vivo Therapeutics [41] In addition to in vitro/ex vivo uses for oligonucleotides that interact with mRNA encoding IAPP and result in reduced expression of the peptide precursor, pro-IAPP, such oligonucleotides may also be administered to type 1 or type 2 diabetics to provide therapeutic benefit. Various well-known modifications to the DNA molecules may be introduced as a means of increasing intracellular stability and half-life. Possible modifications include, but are not limited to, the addition of flanking sequences of ribo- or deoxy- nucleotides to the 5' and/or 3' ends of the molecule or the use of phospho- rothioate or 2' O-methyl rather than phosphodiesterase linkages within the oligodeoxyribonucleotide backbone.

[42] As used in this application, the term 'administered' or 'administering' refers to the introduction of the antisense in vivo to a patient in such a manner that it results in a reduction in expression of pro-IAPP in islets cells. Administration may be a carrier

such as lipid carrier with satisfactory clearance rates and toxicity for in vivo use in the patient, or may be by way of a viral vector, such as an adenoviral vector, and will generally be done by intravenous injection. To enhance delivery of the antisense to the islet cells, the antisense is suitably introduced intravenously to the transhepatic portal vein in the same manner as introduction of transfected islet cells.

[43] Targeted liposomes having targeting ligands, such as an antibody, attached to the liposomes' surfaces may be employed. This approach, where the targeting ligand is bound to the polar head group residues of liposomal lipid components, results in interference by the surface-grafted polymer chains, inhibiting the interaction between the bound ligand and its intended target (Klibanov, A. L., et al., Biochim. Biophys. Acta., 1062:142-148 (1991); Hansen, C. B., et al., Biochim. Biophys. Acta, 1239:133-144 (1995)). In another approach, the targeting ligand is attached to the free ends of the polymer chains forming the surface coat on the liposomes (Allen. T. M., et al., Biochim. Biophys. Acta, 1237:99-108 (1995); Blume, G. , et al., Biochim. Biophys. Acta, 1149: 180-184 (1993)). A therapeutic liposome composition sensitized to a target cell, comprising a liposomal composition composed of pre- formed liposomes having an entrapped oligonucleotide ; and a plurality of conjugates, each conjugate composed of (a) a lipid having a polar head group and a hydrophobic tail, (b) a hydrophilic polymer having a proximal end and a distal end, where the polymer is attached at its proximal end to the head group of the lipid, and (c) a targeting ligand attached to the distal end of the polymer as described in US Patent .Publication No. 20010038851 can also be employed.

[44] Viral vectors may be employed in the delivery of oligonucleotides to islet cells in vivo. For example, adenoviral vectors such as those described in US Patent Publication No. 20050048043 may be employed. Retroviral vectors may also be used. In general, the vectors listed above may be employed for in vivo applications as well. In one embodiment, a viral vector, for example an adenoviral vector, that uses an insulin- responsive promotor is used to direct expression of human proIAPP siRNA in beta cells.

[45] In vivo therapy can be provided for type I diabetic patients , particularly human patients, following islet cell transplantation. In one embodiment of the invention, the transplanted islet cells are cells transfected with an oligonucleotide composition that interacts with mRNA encoding IAPP and results in reduced expression of the peptide precursor, pro-IAPP ex vivo prior to transplantation. In this case, the in vivo treatment assists in the maintenance of reduced amyloid formation. In a second embodiment, the transplanted islet cells are ones that were not previously transfected.

[46] In vivo therapy can also be used for treatment of type II diabetes in patients, particularly human patients, suffering from type II diabetes by administering an oligonucleotide composition that interacts with mRNA encoding IAPP and results in reduced expression of the peptide precursor, pro-IAPP.

[47] The invention will now be further described with reference to the following non- limiting examples. [48] Example 1 - hIAPP siRNA Adenoviral synthesis and purification

[49] The human IAPP-siRNA constructs were cloned into an adenoviral shuttle vector as previously described (Diabetes 53:2190-4, 2004). Briefly, PAGE-purified oligomers were annealed and then ligated into i?g/II/HindIII-linearized pSUPER plasmid. The constructs were then used to transform competent bacteria (DH5#) which were then grown in TB medium. The mini preparations of DNAs (Qiagen miniprep kit) were analyzed by digestion with EcoRI + HindIII and also by sequencing. DNA extracted from the positive clones was used to prepare DNA maxi preparations. The siRNA- pSuper constructs were then tested for their efficiency in suppression of human proIAPP expression in COS-I cells that were transduced with an adenovirus coding for the expression of human proIAPP. Pair 3 that was cloned into pSuper was used for making the adenovirus for further studies with human islets. Error free hIAPP-siRNA expression cassette was purified from siRNA-pSUPER using EcoRI/Hindlll and the siRNA fragments were purified from the gel and ligated into EcoRI/Hindlll-linearized adenoviral shuttle vector (EH006). The construct was used to transform competent bacteria and the miniprep DNAs were screened for single-copy insertion by digestion with EcoRI and HindIII. The plasmids were also tested by PCR. The error-free plasmids and pjM17 adenoviral shuttle vector were co-transfected into 293T cells and the lysate used to amplify the adenovirus. The viral particles were purified from the cell lysates using Vivapure adenopack kit (VivaScience).

[50] Example 2-siRNA-mediated suppression of human proIAPP decreases amyloid induced cell death in COS-I cells.

[51 ] We investigated whether suppression of proIAPP expression by short interfering

RNA (siRNA) prevents amyloid-induced cell death. COS-I cells were transfected with 3 different siRNA#pSuper plasmids specific for human proIAPP (4 Fg) as described above, a non-mammalian siRNA-pSuper as a control for siRNA specificity or an siRNA-pSuper linked to green fluorescent protein (GFP) as a control for transfection efficiency. Cells transfected with active siRNA-pSuper plasmids were allowed to rest (4 h), transduced with an adenovirus expressing fϊbrillogenic human proIAPP linked to GFP (AdhlAPP-GFP, moi: 5, 2 h), and then incubated with fresh media. After 36 h, cells were fixed with 4% paraformaldehyde and apoptotic cells were detected by TUNEL/Hoescht staining. ProIAPP expression in cells transduced with AdhlAPP-GFP was assessed by detection of GFP-expression in fixed cells by fluorescence microscopy as well as Western blot analysis performed on cell lysates 36 h after transduction. Expression of human proIAPP caused cell death manifested as a significant increase in the number of apoptotic cells in hIAPP transduced cells compared to non-transduced control cells. Transfection with all 3 siRNA-pSuper plasmids (Pair 1, 2 and 3) resulted in a significant decrease in the expression of

proIAPP in transduced cells. Interestingly, this reduced level of adenoviral-mediated proIAPP expression in transfected cells was associated with a significant decrease in the number of apoptotic cells compared to hIAPP alone as seen in Figure 1. Thus, these findings provide evidence that inhibition of expression of fϊbrillogenic human proIAPP prevents amyloid-induced cell death.

[52] Example 3-Adenovirus vectors can be used to effectively infect islet cells

[53] To confirm that adenovirus vectors can be effectively used to infect islet cells, transfection efficiency was assessed by staining Balb/c islets for b-galactosidase (Lac Z) as previously described (O'Brien T et al. Diabetes Research and Clinical Practice 44: 157, 163, 1999). Briefly, islet cells were isolated from Balb/c mice using collegenase digestion of the pancreas. Following isolation, islets were pre-cultured for a period of 3-7 days in DMEM with 10% fetal calf serum at 37°C. Subsequently, the islet cells were transduced overnight with 0, 5 or 10 pfu of Adenovirus-Lac Z construct (Ad-LacZ). Efficiency of gene transfer was determined by gross inspection and estimation of the percentage of β-galactosidase positive cells.

[54] Visual inspection after overnight transduction with Ad-Lacz clearly showed that there is significant transduction of islets cells with beta-gal as reflected by coloration of the cells. Furthermore the transduction efficiency increases with increased MOI. These results indicate that beta-cells can be transduced effectively with adenovirus vectors.

[55] Example 4-Suppression of expression of proIAPP in isolated human islets following transduction with Ad-hIAPP-siRNA.

[56] Isolated human islets (50 islets/well) were transduced with different dilutions of

Ad-hlAPP-siRNA (Pair 3). 96 hours post-adenoviral transduction, islets were lysed in NP-40 lysis buffer. Aliquots of protein from islet lysates were electrophoresed on a polyacrylamide gel using Tris-tricine buffer followed by immunoblot analysis using antisera #7323 (Peninsula Laboratories). Membranes were then washed and incubated with horseradish peroxidase-conjugated anti-rabbit (or anti-mouse for GAPDH) IgG (Amersham, Baie dUrfe, QC) diluted 1 :5000 for 1 h.Immunodetection was performed using an enhanced chemiluminescence detection kit (Amersham). The results demonstrate high levels of immature (pro)IAPP in cultured islets compared to pre- culture islets and the absence of expression after transduction with Ad-hIAPP-siRNA. These results demonstrate that the Ad-hlAPP siRNA construct effectively targets LAPP and reduces expression of its precursor.

[57] Example 5- siRNA-mediated suppression of human proIAPP decreases islet amyloid formation in cultured human islets.

[58] To determine whether suppression of LAPP expression prevents islet amyloid formation in primary islets, human islets were transduced with Ad-hIAPP-siRNA (Pair 3, moi 50) overnight and then cultured for 10 days in CMRL (the same medium used in clinical human islet transplantation) in 11.1 mM glucose. Our previous studies have

shown that human islets form amyloid rapidly (days) during culture therefore cultured human islets provide a valuable in situ model for rapid amyloid formation. Islet amyloid was detected by thioflavin S (blue) staining and insulin-positive (red) cells by immunostaining in paraffin embedded sections of islets following culture (dlO) or after isolation (dθ). Briefly, islet sections were immunostained with guinea pig anti-insulin (1:100 dilution, overnight, 4 C) and then incubated with Texas red anti-guinea pig secondary antibody (1:100, 1 hour at room temperature). Following insulin staining, islet sections were stained with thioflavin S (0.5% for 5 minutes). Results demonstrated that there was islet amyloid present and loss of insulin immunoreactive cells in the untreated cultured islets. Amyloid is decreased and number of insulin- positive cells increased in cultured islets transduced with Ad-hIAPP-siRNA. These data show that suppression of IAPP expression prevents amyloid.formation in human islets and preserves insulin production in beta cells.

[59] Example 6- siRNA-mediated suppression of human proIAPP enhances survival of human islets in culture.

[60] To determine whether suppression of IAPP expression decreases death of cultured human islet cells, isolated human islets were transduced with Ad-hlAPP-siRNA (Pair 3, moi 50, 20 and 10) overnight or left untreated, and then cultured for 2 weeks. Islets were then fixed in paraformaldehyde and paraffin embedded islet sections were then incubated with TUNEL reaction mixture (Roche Diagnostics, Laval, QC) for 1 h at 37°C and then stained with Hoechst-33342 for 10 min. The slides were viewed using a Zeiss Axioplan 2 microscope equipped for epifluorescence with a Sensys high- performance charge-coupled device (HCCD) camera (Photometries, Tucson, AZ) and Quips Pathvysion imaging software (Applied Imaging, Santa Clara, CA). Images were captured with red or Dapi filters and pseudocolored in Pathvysion to create the final image. Following hand-counting the number of blue (Hoecsht-positive) and pink (TUNEL-positive cells) in separate fields from several sections, the percent of TUNEL-positive cells was quantified by dividing the total (TUNEL plus Hoechst positive) number of cells by the number of TUNEL-positive cells (X 100%). As seen in Figure 2, there was significantly less islet cell death in cultures treated with the Ad- hlAPP-siRNA compared to controls. These data show that suppression of IAPP expression in human islets by adenoviral transduction with human IAPP siRNA decreases human islet cell apoptosis in culture.

[61] Example 7- siRNA-mediated suppression of human proIAPP increases survival of insulin but not glucagon-producing cells.

[62] To investigate whether siRNA-mediated suppression of amyloid formation enhances survival of islet beta cells, isolated human islets were transduced with Ad- hlAPP-siRNA (Pair 3, moi 50) overnight and then cultured for 10 days (CMRL 11.1 mM glucose). Paraffin-embedded islet sections were then double immunostained for insulin (to detect beta cells) and glucagon (to detect alpha cells). Islet sections were

first incubated with guinea pig anti-insulin antibody (1:100 dilution, overnight) followed by incubation with Alexa 488 anti guinea pig antibody (1:100, one hour), then incubated with rabbit anti-glucagon antibody (1:75, 1 hour) and Texas red anti rabbit secondary antibody (1 :100, 1 hour). Data revealed that the number of insulin- but not glucagon-positive islet cells was decreased in non-transduced (-Ad-hIAPP-siRNA) cultured islets, compared to freshly isolated or Ad- MAPP-siRNA-transduced islets cultured for 10 days. Thus, amyloid-induced loss of cultured human islet cells is specific for beta cells and can be prevented by inhibition of human proIAPP expression using Ad-hIAPP-siRNA. Prevention of islet amyloid formation can therefore enhance beta cell survival in human islet grafts following transplantation and preserve beta cells in type 2 diabetic patients.

[63] Example 8- siRNA-mediated suppression of human proIAPP increases insulin content and glucose-stimulated insulin secretion in cultured human islets.

[64] To investigate whether prevention of islet amyloid formation will enhance function of primary islet beta cells freshly isolated human islets were transduced with Ad- hIAPP-siRNA (Pair 3, moi 50) overnight or left non- transduced and then cultured for 10 days in CMRL (11.1 mM glucose). Function of beta cells was assessed by performing glucose stimulated insulin secretion test (GSIS) following 10 days culture. Briefly, islets were pre-incubated in Krebs buffer containing low (1.67 mM) glucose for 2 hours followed by one hour incubation in low (1.67 mM) or high (16.7 mM) glucose and media collected or islets extracted in acetic acid containing 0.1% BSA. Insulin secretion and islet insulin content were determined by ELISA (Linco). Both glucose-stimulated insulin secretion (expressed as % basal) and islet insulin content were increased in islets transduced with Ad-hiAPP-siRNA compared to non- transduced controls as seen in Figure 3A and 3B, respectively. These data show that inhibition of islet amyloid formation markedly enhances function of human islets and their ability to produce insulin. Prevention of islet amyloid formation may therefore enhance beta cell function in transplanted human islets and type 2 diabetic patients.

[65] Example 9-siRNA mediated effect in vivo using a Type I diabetes model

[66] To determine whether inhibition of islet amyloid formation using an siRNA approach in vivo can enhance survival and function of human islets transplanted into diabetic mice the following study is conducted. Freshly isolated human islets are transduced overnight with Ad-hIAPP-siRNA as per the optimal conditions described in Example 2, control adenovirus, or left untreated. Transduced islets are cultured for 48 h to allow expression of human LAPP siRNA. A suboptimal number of islets (1,000 IE) are transplanted under the kidney capsule of NOD.sc/V/mice that have previously been rendered diabetic (non-fasted blood glucose between 22-28 mM) by administration of STZ (250 mg/kg, i.p.).

[67] Blood samples are taken from the saphenous vein twice weekly to measure blood glucose (by glucometer) and serum insulin levels (using a human specific-insulin

ELISA). An IPGTT is performed at 8 wks post- transplant, prior to removal of islet grafts. Following removal of the graft by nephrectomy, blood glucose levels are monitored to ensure that normoglycemia is maintained by the human islet graft and not by recovery of the recipient's own islets. All islet grafts are fixed in 4% paraformaldehyde, paraffin-embedded, and graft sections analysed histologically for the presence of amyloid, and insulin- and glucagon-positive cells. Beta cell mass and amyloid area are determined by quantitative image analysis. Analysis will include correlation of beta cell mass with graft amyloid area and blood glucose at time of sacrifice, as well as Kaplan-Meier analysis of the proportion of recipients of treated and untreated islets that remain non-diabetic. Although we do not expect to see major differences in beta cell proliferation (Ki67) or death (TUNEL) still remaining at 8 weeks post-transplant, we will sacrifice some recipients for graft analysis at 5 days post-transplant, when such differences between treated and untreated groups may be apparent. Given the donor-to-donor and islet preparation-to-preparation variability, we anticipate performing - with islets from each donor - 2-3 transplants for each condition listed above. We will repeat these experiments using islets from at least 6 different human islet preparations.

[68] Example 10- siRNA mediated effect in vivo using a Type II diabetes model

[69] To determine whether a decrease in IAPP expression in β-cells using an siRNA approach can decrease hyperglycemia in a type II diabetes in vivo model, the following study is conducted. A transgenic mouse model that over expresses human IAPP in pancreatic β-cells as previously described is used (Verchere CB et al., Proc. Natl. Acad. Sci, USA 93: 3492-3496, 1996). Briefly, an adenovirus carrying the siRNA constructs targeting IAPP described in this invention under the control of a rat promoter will be systemically administered to male transgenic mice over expressing human IAPP as described in Ayuso et al. 2004. Control animals are infected with empty adenovirus vectors.

[70] Blood samples are taken from the saphenous vein twice weekly to measure blood glucose (by glucometer) and serum insulin levels (using a human specific-insulin ELISA). An IPGTT is performed at 3, 6, 9 and 12 months prior to sacrifice. The pancreas is harvested and fixed in 4% paraformaldehyde, paraffin-embedded, and analysed histologically for the presence of amyloid. Beta cell mass and amyloid area are determined by quantitative image analysis. Analysis will include correlation of beta cell mass with pancreas amyloid area and blood glucose at time of sacrifice.