RNAi inhibition of alpha-ENaC expression

1. A composition comprising an iRNA agent for inhibiting the expression of an alpha-ENaC gene, wherein the iRNA agent comprises a sense strand and an antisense strand, wherein the antisense strand comprises a nucleotide sequence of nucleotides 2-19 of SEQ ID NO: 980, and wherein the sense strand is complementary to the antisense strand.

2. The composition of claim 1 , wherein the sense strand of the iRNA agent comprises a nucleotide sequence of nucleotides 1-18 of SEQ ID NO: 979.

3. The composition of claim 1 , wherein the antisense strand of the iRNA agent and the sense strand of the iRNA agent are each 19 to 23 nucleotides in length.

4. The composition of claim 1 , wherein the iRNA agent comprises at least one modified nucleotide and/or at least one phosphate linker modification.

5. The composition of claim 2 , wherein the iRNA agent comprises at least one modified nucleotide and/or at least one phosphate linker modification.

6. The composition of claim 4 , wherein the iRNA agent comprises one or more 2′-modified nucleotides and/or one or more phosphorothioates.

7. The composition of claim 5 , wherein the iRNA agent comprises one or more 2′-modified nucleotides and/or one or more phosphorothioates.

8. The composition of claim 6 , wherein the one or more 2′-modified nucleotides are independently selected from the group consisting of: 2′-deoxy, 2′-deoxy-2′-fluoro, 2′- 0 -methyl, 2′-O-methoxyethyl (2′-O-MOE), 2′-O-aminopropyl (2′-O-AP), 2′-O-dimethylaminoethyl (2′-O-DMAOE), 2′-O-dimethylaminopropyl (2′-O-DMAP), 2′-O- dimethylaminoethyloxyethyl (2′-O-DMAEOE), and 2′-O-N-methylacetamido (2′-O-NMA).

9. The composition of claim 7 , wherein the one or more 2′-modified nucleotides are independently selected from the group consisting of: 2′-deoxy, 2′-deoxy-2′-fluoro, 2′-O-methyl, 2 ′-O-methoxyethyl (2′-O-MOE), 2 ′- O-aminopropyl (2′-O-AP), 2′-O-dimethylaminoethyl (2′-O-DMAOE), 2′-O-dimethylaminopropyl (2′-O-DMAP), 2′-O-dimethylaminoethyloxyethyl (2′-O-DMAEOE), and 2′-O-N-methylacetamido (2′-O-NMA).

10. The composition of claim 4 , wherein the sense strand and/or the antisense strand contains a 3′ overhang.

11. The composition of claim 4 , wherein the sense strand and/or the antisense strand contains a 5′ overhang.

12. The composition of claim 4 , wherein the iRNA agent comprises at least one blunt end.

13. The composition of claim 4 , further comprising a buffer, diluent, penetration enhancer, carrier compound, and/or pharmaceutically acceptable carrier or excipient.

14. The composition of claim 4 , wherein the composition is presented in unit dosage form.

15. The composition of claim 1 , wherein the iRNA agent is ligated to one or more diagnostic compound, reporter group, cross-linking agent, nuclease-resistance conferring moiety, natural or unusual nucleobase, lipophilic molecule, cholesterol, lipid, lectin, steroid, uvaol, hecogenin, diosgenin, terpene, triterpene, sarsasapogenin, Friedelin, epifriedelanol-derivatized lithocholic acid, vitamin, carbohydrate, dextran, pullulan, chitin, chitosan, synthetic carbohydrate, Oligo Lactate 15-mer, natural polymer, low- or medium-molecular weight polymer, inulin, cyclodextrin, hyaluronic acid, protein, protein-binding agent, integrin-targeting molecule, epithelial receptor ligand, polycationic, peptide, polyamine, peptide mimic, and/or transferrin.

16. The composition of claim 4 , further comprising one or more known agents effective in treatment of ENaC-related disorders.

17. The composition of claim 16 , wherein the known agent is selected from the group consisting of: anti-inflammatory drug, bronchodilatory drug, antihistamine, anti-tussive drug, antibiotic, DNase drug substance, epithelial sodium channel blocker.

18. A method of treating a human subject having a pathological state mediated at least in part by alpha-ENaC expression, the method comprising the step of administering to the subject a therapeutically effective amount of a composition of claim 5 .

19. The method of claim 18 wherein the pathological state is cystic fibrosis, primary ciliary dyskinesia, chronic bronchitis, chronic obstructive pulmonary disease (COPD), asthma, respiratory tract infections, lung carcinoma, Liddles syndrome, hypertension, renal insufficiency, and/or electrolyte imbalance.

20. The method of claim 18 , wherein the composition is administered via inhalation/intranasal administration or systemically or subcutaneously.

21. A method of inhibiting the expression of an alpha-ENaC gene in a cell, the method comprising administering to the cell an effective amount of a composition of claim claim 5 .