Compositions for regulating iron homeostasis and methods of using same
The present disclosure relates to hemojuvelin-IgG Fc domain fusion proteins, variants, derivatives, fragments and peptide mimetics derived therefrom and methods of using these fusion proteins for the regulation of iron homeostasis and the treatment of diseases related to iron homeostasis.
1. A composition comprising a fusion protein wherein the fusion protein comprises the sequence of SEQ ID NO:9.
2. The composition of claim 1 , wherein the fusion protein is at least 98% pure as determined by size exclusion chromatography.
3. The composition of claim 1 , wherein the fusion protein is glycosylated.
4. The composition of claim 3 , wherein the glycosylation pattern is a mammalian glycosylation pattern.
5. The composition of claim 4 , wherein asparagine 83, asparagine 178 and/or asparagine 337 are glycosylated.
6. The composition of claim 4 , wherein the glycosylation pattern is from a Chinese hamster ovary (CHO) cell line.
7. The composition of claim 1 , wherein the N-terminal amino acid of the fusion protein is glutamine.
8. The composition of claim 7 , wherein the N-terminus of the N-terminal amino acid of the fusion is QCKILRCNAE (SEQ ID NO: 10).
9. The composition of claim 1 , wherein the composition is substantially pyrogen free.
10. The composition of claim 1 , wherein the serum half-life of the fusion protein is at least 10 hours.
11. The composition of claim 1 , wherein the fusion protein binds to bone morphogenic protein-6 (“BMP-6”) with a KD of at least 10 −7 M and inhibits BMP-6 signaling.
12. The composition of claim 1 , wherein the composition increases hemoglobin and/or hematocrit in a subject when administered.
13. The composition of claim 1 , wherein the composition increases hemoglobin and/or hematocrit to at least normal levels in an anemic subject when administered to the anemic subject for one month or more.
14. The composition of claim 1 , wherein the fusion protein forms a homodimer.
15. The composition of claim 14 , wherein the homodimer is formed in the Fc hinge regions.
16. The composition of claim 15 , wherein the homodimer is formed between cysteines in the Fc hinge regions via a disulfide bond.
17. A nucleic acid molecule that encodes the fusion polypeptide of claim 1 .
18. The nucleic acid molecule of claim 17 , wherein the nucleic acid molecule encodes the fusion protein of claim 1 and comprises the sequence of SEQ ID NO: 11.
19. A mammalian cell comprising the nucleic acid sequence of claim 18 .
20. The mammalian cell of claim 19 , wherein the cell is a CHO cell.
21. A method of increasing serum iron levels in a subject in need thereof by administering a therapeutically effective amount of the composition of claim 1 to the subject, thereby increasing serum iron levels.
22. A composition comprising a fusion protein, wherein the fusion protein comprises an N-terminal polypeptide and a C-terminal polypeptide, wherein the N-terminal polypeptide comprises the sequence of SEQ ID NO: 1 and wherein the C-terminal peptide comprises a sequence selected from the group consisting of SEQ ID NOs: 3, 4, 5, 6, and 7.
23. The composition of claim 22 , wherein the fusion protein is at least 98% pure as determined by size exclusion chromatography.
24. The composition of claim 22 , wherein the fusion protein is glycosylated.
25. The composition of claim 24 , wherein the glycosylation pattern is a mammalian glycosylation pattern.
26. The composition of claim 25 , wherein the glycosylation pattern is from a Chinese hamster ovary (CHO) cell line.
27. The composition of claim 22 , wherein the N-terminal amino acid of the fusion protein is glutamine.
28. The composition of claim 27 , wherein the N-terminus of the N-terminal amino acid of the fusion is QCKILRCNAE (SEQ ID NO: 10).
29. The composition of claim 22 , wherein the composition is substantially pyrogen free.
30. The composition of claim 22 , wherein the serum half-life of the fusion protein is at least 10 hours.
31. The composition of claim 22 , wherein the fusion protein binds to bone morphogenic protein-6 (“BMP-6”) with a KD of at least 10 −7 M and inhibits BMP-6 signaling.
32. The composition of claim 22 , wherein the composition increases hematocrit in a subject when administered.
33. The composition of claim 22 , wherein the composition increases hematocrit to at least normal levels in an anemic subject when administered to the anemic subject for one month or more.
34. The composition of claim 22 , wherein the fusion protein forms a homodimer.
35. A nucleic acid molecule that encodes the fusion protein of claim 22 .
36. The nucleic acid of claim 35 , wherein the nucleic acid molecule encodes the fusion protein of claim 22 and comprises the sequence of SEQ ID NO: 11.
37. A mammalian cell comprising the nucleic acid sequence of claim 35 .
38. The mammalian cell of claim 37 , wherein the cell is a CHO cell.
39. A method of increasing serum iron levels and/or improving anemia in a subject in need thereof by administering a therapeutically effective amount of the composition of claim 22 to the subject, thereby increasing serum iron levels and/or improving anemia.