Virus-derived Serpin Reduces Immuno-coagulopathic Damage in Murine Colitis by Targeting the urokinase-type Plasminogen Activator Receptor (uPAR) and Complement

A virus-derived serpin, Serp-1, has proven efficacy in treating inflammatory and coagulation disorders in preclinical and clinical studies. Serp-1 evolved over millions of years to block host immune responses, targeting serine proteases in immune and coagulation pathways. Treatment with PEGylated Serp-1 (PEGSerp-1) protein reduced lung injury in both lupus lung hemorrhage and SARS-CoV-2 models. Here, PEGSerp-1 effects on immune-coagulopathic responses is examined in a mouse colitis model. Inflammatory bowel disease (IBD) is associated with life-threatening complications with severe inflammation, bleeding, vasculitis, cancer and toxic megacolon. Ser ine p rotease cascades activate coagulation and complement pathways throughout the human body and are regulated by in hibitors, termed serpins , that can reduce gut inflammation. Prophylactic PEGSerp-1 significantly improved survival in severe 5% Dextran sodium sulfate (DSS) colitis, reducing inflammation and crypt damage. Colon damage and inflammation were also reduced after either acute colitis induced by 5%DSS or repeat 2% DSS induced colitis. PEGSerp-1 reduced inflammatory M1 macrophage invasion, urokinase-type plasminogen activator receptor (uPAR), fibrinogen and complement on immunohistochemical analysis. PEGSerp-1 reduced uPAR expression in human macrophage, but not colon cells. Here we report analysis of PEGSerp-1 as a tissue and macrophage targeting therapeutic for colitis, reducing immune and coagulation induced damage in the colon.