Compositions and methods of treating Facioscapulohumeral muscular dystrophy

1. A method of treating facioscapulohumeral muscular dystrophy (FSHD) in a subject comprising administering to the subject a therapeutic amount of a polynucleotide-antibody conjugate comprising an anti-transferrin receptor antibody or antigen binding fragment thereof conjugated to a polynucleotide, wherein the polynucleotide is from 19 to 30 nucleotides in length, and wherein the polynucleotide-antibody conjugate mediates RNA interference against human DUX4 mRNA and mediates downregulation of DUX4 regulated genes comprising ZSCAN4 and LEUTX, thereby treating FSHD in the subject.

2. The method of claim 1 , wherein the polynucleotide is a single stranded polynucleotide.

3. The method of claim 2 , wherein the single stranded polynucleotide is an antisense oligonucleotide (ASO) or a phosphorodiamidate morpholino oligomers (PMO).

4. The method of claim 1 , wherein the anti-transferrin receptor antibody or antigen binding fragment thereof binds to a transferrin receptor on a cell surface of a muscle cell.

5. The method of claim 1 , wherein the polynucleotide-antibody conjugate is delivered to a muscle cell of the subject.

6. The method of claim 5 , wherein the muscle cell expresses human DUX4 mRNA.

7. The method of claim 6 , wherein expression levels of human DUX4 mRNA are reduced by the polynucleotide-antibody conjugate.

8. The method of claim 1 , wherein the FSHD is caused by genetic and epigenetic changes in D4Z4 DNA region of long arm of chromosome 4 in muscle cells of the subject.

9. The method of claim 1 , wherein the FSHD is associated with muscle atrophy.

10. The method of claim 1 , wherein the RNA interference against the human DUX4 mRNA prevents muscle atrophy or prevents progress of muscle atrophy in the subject.

11. The method of claim 1 , wherein the FSHD is FSHD type 1 or FSHD type 2.

12. The method of claim 1 , wherein the polynucleotide-antibody conjugate is formulated for parenteral administration.

13. The method of claim 1 , wherein the polynucleotide comprises at least one 2′ modified nucleotide, at least one modified internucleotide linkage, or at least one inverted abasic moiety.

14. The method of claim 1 , wherein the polynucleotide hybridizes to at least 8 contiguous bases of a target sequence of the human DUX4 mRNA.

15. The method of claim 1 , wherein the polynucleotide comprises a sequence selected from SEQ ID NOs: 72, 76, 126, 131, 132, 134-136, 212, 216, 266, 271, 272, and 274-276.

16. The method of claim 1 , wherein the polynucleotide-antibody conjugate comprises a linker connecting the anti-transferrin receptor antibody or antigen binding fragment thereof to the polynucleotide.

17. The method of claim 13 , wherein the at least one 2′ modified nucleotide comprises 2′-O-methyl, 2′-O-methoxyethyl (2′-O-MOE), 2′-O-aminopropyl, 2′-deoxy, 2′-deoxy-2′-fluoro, 2′-O-aminopropyl (2′-O-AP), 2′-O-dimethylaminoethyl (2′-O-DMAOE), 2′-O-dimethylaminopropyl (2′-O-DMAP), 2′-O-dimethylaminoethyloxyethyl (2′-O-DMAEOE), or 2′-O—N-methylacetamido (2′-ONMA) modified nucleotide, comprises locked nucleic acid (LNA) or ethylene nucleic acid (ENA), or comprises a combination thereof.

18. The method of claim 13 , wherein the at least one modified internucleotide linkage comprises a phosphorothioate linkage or a phosphorodithioate linkage.

19. The method of claim 13 , wherein the polynucleotide comprises 3 or more 2′ modified nucleotides selected from 2′-O-methyl modified nucleotide and 2′-deoxy-2′-fluoro modified nucleotide.

20. The method of claim 13 , wherein the polynucleotide comprises a 5′-terminal vinylphosphonate modified nucleotide.

21. The method of claim 1 , wherein the polynucleotide-antibody conjugate has a polynucleotide to antibody ratio of 1 to 4.

22. The method of claim 1 , wherein the polynucleotide-antibody conjugate further reduces expression of one or more DUX4 regulated genes selected from MBD3L2, TRIM43, PRAMEF1, and KHDC1L.