Systemic delivery of adeno-associated virus vector expressing gamma-sarcoglycan and the treatment of muscular dystrophy

1. A method of treating muscular dystrophy in a subject in need thereof, comprising the step of administering a recombinant adeno-associated virus (rAAV) scAAVrh74.MHCK7.hSGCG to the subject, wherein the rAAV is administered using a systemic route of administration and at a dose of about 4.63×10 12 vg/kg, about 1.85×10 13 vg/kg, or about 7.41×10 13 vg/kg based on a linearized plasmid as the quantitation standard, and wherein the rAAV comprises a nucleotide sequence that is identical to SEQ ID NO: 7 or SEQ ID NO: 10.

2. The method of claim 1 , wherein the level of gamma-sarcoglycan gene expression in a cell of the subject is increased after administration of the rAAV as compared to the level of gamma-sarcoglycan gene expression before administration of the rAAV;

wherein the average rAAV copy number in a muscle cell of the treated subject is at least 0.01 copy per nucleus;

wherein the centralized nuclei percentage and/or the fibrosis is reduced in the muscle of the treated subject as compared to the level before administration of the rAAV;

wherein motor function is improved in said subject as compared to the motor function of said subject before administration of the rAAV;

wherein the North Star Assessment for Dysferlinopathies (NSAD) are increased in said subject as compared to the NSAD of said subject before administration of the rAAV; and/or

wherein the ALT and AST levels are reduced in said subject as compared to the ALT and AST levels of said subject before administration of the rAAV.

3. The method of claim 2 , wherein the motor function is improved by at least 5%, 10%, 15%, 20%, 25%, 30%, 40%, 45%, or 50%.

4. The method of claim 2 , wherein the level of gamma-sarcoglycan protein expression is increased by at least 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40% after administration of the rAAV as compared to the gamma-sarcoglycan protein level before administration of the rAAV.

5. The method of claim 1 , wherein the rAAV is administered using an intravenous route.

6. The method of claim 1 , wherein the muscular dystrophy is limb-girdle muscular dystrophy.

7. The method of claim 1 , wherein the number of gamma-sarcoglycan positive fibers in the muscle tissue of the subject is increased by at least 40, 41, or 42% after administration of the rAAV as compared to the number of gamma-sarcoglycan positive fibers before administration of the rAAV.

8. The method of claim 1 , wherein the serum CK level in the subject is decreased by at least 82, 83, 84, 85, 86, 87, 88, 89, or 90% by 60 days to 90 days, 60 days, or 90 days after administration of the rAAV as compared to the serum CK level before administration of the rAAV.

9. The method of claim 1 , wherein the level of alpha-sarcoglycan and/or beta-sarcoglycan in the subject is increased after administration of the rAAV as compared to the level of alpha-sarcoglycan and/or beta-sarcoglycan before administration of the rAAV.

10. The method of claim 1 , wherein the rAAV is administered at a dose of about 4.63×10 12 vg/kg based on a linearized plasmid as the quantitation standard.

11. The method of claim 1 , wherein the rAAV is administered at a dose of about 1.85×10 13 vg/kg based on a linearized plasmid as the quantitation standard.

12. The method of claim 1 , wherein the rAAV is administered at a dose of or about 7.41×10 13 vg/kg based on a linearized plasmid as the quantitation standard.

13. The method of claim 1 , wherein the rAAV comprises the nucleotide sequence of SEQ ID NO: 7.

14. The method of claim 1 , wherein the rAAV comprises the nucleotide sequence of SEQ ID NO: 10.