DAF-MCP chimeric proteins, process to manufacture the same and use of the chimeric protein for treating pathological conditions involving the complement system
The complement system is part of the innate immune system and is highly regulated by regulatory proteins belonging to the Regulators of Complement Activation (RCA) family. It is known that lack of regulation causes damage to host cells and deficiencies in the regulation is also linked to diseases such as age-related macular degeneration, atypical hemolytic uremic syndrome, and dense deposit disease. The regulatory proteins primarily include decay-accelerating factor (DAF; CD55), membrane cofactor protein (MCP; CD46), complement receptor 1 (CR1; CD35), factor H (FH) and C4b-binding protein (C4BP). Structurally, these proteins are composed of repeating complement control protein (CCP) domains where 2-4 successive domains contribute to the regulatory functions termed as decay-accelerating activity (DAA) and cofactor activity (CFA). However, no four-domain chimeric protein currently exists having both strong DAA (CP-DAA and AP-DAA) and strong CFA (C3b-CFA and C4b-CFA). Therefore, chimeric protein DCP (i.e., a dual-activity regulator) was created.
1 . An engineered chimeric protein for inhibition of complement pathways consisting of domains of Decay-Accelerating Factor (DAF) and membrane cofactor protein (MCP) joined by linkers, wherein domains of DAF are selected from D2, D3 and D4 and domains of MCP are selected from M2, M3 and M4, and wherein the engineered chimeric protein is selected from the group consisting of the proteins set forth in SEQ ID NOs: 4-33.
2 . The engineered chimeric protein of claim 1 , wherein the engineered chimeric protein is the protein set forth in SEQ ID NO: 19.
3 . A process to obtain the engineered chimeric protein according to claim 1 comprising expressing the engineered chimeric protein according to claim 1 from a bacterial and/or yeast expression vector.
4 . A method of treating paroxysmal nocturnal hemoglobinuria (PNH); age-related macular degeneration (AMD); atypical hemolytic uremic syndrome (aHUS); dense deposit disease (DDD); or an autoimmune disease selected from the group consisting of experimental allergic neuritis, type II collagen-induced arthritis, myasthenia gravis, hemolytic anemia, glomerulonephritis, and immune complex-induced vasculitis; adult respiratory distress syndrome; stroke; heart attack; multiple sclerosis; and burn injuries; comprising administering a therapeutically-effective amount of the engineered chimeric protein according to claim 3 to a subject in need thereof, wherein said engineered chimeric protein has dual activity by enhancing affinity towards factor 1 and avidity towards C3b/C4b by inactivating the C3/C5 convertase.
5 . A composition consisting of the engineered chimeric protein according to claim 1 , along with pharmaceutically acceptable excipients.
6 . The composition according to claim 5 , wherein the composition is formulated for administration by a route selected from the group consisting of intravenous, oral, intraperitoneal, intradermal, intramuscular, intranasal, subcutaneous, intraspinal, intratracheal and intracranial administration.
7 . The composition according to claim 5 , wherein the composition has inhibitory activity towards classical pathway (CP), alternative pathway (AP) and lectin pathway (LP).
8 . The composition according to claim 5 , which is used for treating complement-mediated diseases, autoimmune diseases, and a disorder selected from the group consisting of age-related macular degeneration, rheumatoid arthritis, spinal cord injury, Parkinson's disease, Alzheimer's disease, cancer, and respiratory disorders conferring resistance to human complement-mediated damage, experimental allergic neuritis, type II collagen-induced arthritis, myasthenia gravis, hemolytic anemia, glomerulonephritis, and immune complex-induced vasculitis.
9 . The composition according to claim 8 , wherein the respiratory disorders are selected from the group consisting of chronic obstructive pulmonary disease (COPD), allergic inflammation, emphysema, bronchitis, bronchiecstasis, cyctic fibrosis, tuberculosis, pneumonia, neonatal respiratory distress syndrome (RDS), adult RDS, rhinitis and sinusitis.
10 . A gene therapy vector for protection from the human complement, consisting of a gene encoding an engineered chimeric protein according to claim 1 .