Methods for reducing severity of pulmonary fibrosis

1. A method of treating a lung injury at risk of progressing to a fibrotic lung disease in a subject in need thereof comprising administering to the subject a pharmaceutical composition comprising a therapeutic amount of IL-6 polypeptide, a variant IL-6 polypeptide having no more than ten amino acid differences as compared to an IL-6 polypeptide encoded by SEQ ID NO:13 while retaining IL-6 activity, or pharmaceutically acceptable salts thereof, wherein the therapeutic amount increases renewal of alveolar epithelial cell 2 (AEC2) stem cells, repairs the injury, reduces lung fibrosis, or a combination thereof.

2. The method according to claim 1 , wherein the lung injury or fibrotic lung disease is pulmonary fibrosis.

3. The method according to claim 1 , wherein the lung injury or fibrotic lung disease is idiopathic pulmonary fibrosis (IPF).

4. The method according to claim 1 , wherein the lung injury is a bleomycin-induced lung injury.

5. The method according to claim 1 , wherein the method further comprises administering to the subject a therapeutic amount of one or a plurality of immunomodulators, analgesics, anti-inflammatory compounds, anti-fibrotic compounds, proton pump inhibitors, oxygen therapy, or combinations thereof.

6. The method according to claim 5 ,

i. wherein the immunomodulator is prednisone, azathioprine, mycophenolate, mycophenolate mofetil, colchicine, or interferon-gamma 1b; or

ii. wherein the analgesic is codeine, hydrocodone, oxycodone, methadone, hydromorphone, morphine, or fentanyl; or

iii. wherein the anti-inflammatory compound is aspirin, celecoxib, diclofenac, diflunisal, etodolac, ibuprofen, indomethacin, ketoprofen, ketorolac nabumetone, naproxen, nintedanib, oxaprozin, pirfenidone, piroxicam, salsalate, sulindac, or tolmetin; or

iv. wherein the anti-fibrotic compound is nintedanib or pirfenidone; or

v. wherein the proton pump inhibitor is omeprazole, lansoprazole, dexlansoprazole, esomeprazole, pantoprazole, rabeprazole, or ilaprazole.

7. The method according to claim 1 , wherein the IL-6 polypeptide is a recombinant IL-6 polypeptide or pharmaceutically acceptable salt thereof.

8. The method according to claim 1 , wherein the therapeutic amount is effective to increase the cell surface expression of hyaluronan in one or a plurality of alveolar epithelial cell 2 (AEC2) cells in the subject.

9. The method according to claim 1 , wherein the therapeutic amount increases toll-like receptor 4 (TLR4)-hyaluronan (HA) signaling in the subject.

10. A method of increasing alveolar epithelial cell 2 (AEC2) stem cell renewal in a lung to reduce progression of a lung injury to a fibrotic disease in a subject in need thereof comprising administering to the subject a pharmaceutical composition comprising a therapeutic amount of IL-6 polypeptide, a variant IL-6 polypeptide having no more than ten amino acid differences as compared to an IL-6 polypeptide encoded by SEQ ID NO:13 while retaining IL-6 activity, or pharmaceutically acceptable salts thereof.

11. The method according to claim 10 , wherein the lung injury or fibrotic lung disease is pulmonary fibrosis.

12. The method according to claim 10 , wherein the lung injury or fibrotic lung disease is idiopathic pulmonary fibrosis (IPF).

13. The method according to claim 10 , wherein the lung injury is a bleomycin-induced lung injury.

14. The method according to claim 10 , wherein the method further comprises administering to the subject a therapeutic amount of one or a plurality of immunomodulators, analgesics, anti-inflammatory compounds, anti-fibrotic compounds, proton pump inhibitors, oxygen therapy, or combinations thereof.

15. The method according to claim 14 ,

i. wherein the immunomodulator is prednisone, azathioprine, mycophenolate, mycophenolate mofetil, colchicine, or interferon-gamma 1b; or

ii. wherein the analgesic is codeine, hydrocodone, oxycodone, methadone, hydromorphone, morphine, or fentanyl; or

iii. wherein the anti-inflammatory compound is aspirin, celecoxib, diclofenac, diflunisal, etodolac, ibuprofen, indomethacin, ketoprofen, ketorolac nabumetone, naproxen, nintedanib, oxaprozin, pirfenidone, piroxicam, salsalate, sulindac, or tolmetin; or

iv. wherein the anti-fibrotic compound is nintedanib or pirfenidone; or

v. wherein the proton pump inhibitor is omeprazole, lansoprazole, dexlansoprazole, esomeprazole, pantoprazole, rabeprazole, or ilaprazole.

16. The method according to claim 10 , wherein the IL-6 polypeptide is a recombinant IL-6 polypeptide or pharmaceutically acceptable salt thereof.

17. The method according to claim 10 , wherein the therapeutic amount increases the cell surface expression of hyaluronan in one or a plurality of alveolar epithelial cell 2 (AEC2s) in the subject.

18. The method according to claim 10 , wherein the therapeutic amount increases toll-like receptor 4 (TLR4)-hyaluronan (HA) signaling in the subject.