1496-P: Resatorvid, an Inhibitor of Toll-Like Receptor-4, Protects Allogenic Islets from Inflammatory and Immune Response

Abstract

Purpose: Loss of islet mass by instant blood mediated inflammatory reaction (IBMIR) and immunological rejection are major hurdles currently facing the field of islet transplantation. Toll-like receptor 4 (TLR4) plays a central role in inflammation and shaping adaptive immune response. We investigated the protective effects of resatorvid (TAK-242) using in vitro models of islet transplantation. Methods: Soluble TAK-242 or TAK-242 conjugated to the surface of islets utilizing copper-free click chemistry with a cleavable chemical linker were used. Islets were mixed with allogenic blood for a period of 3 hours and plasma levels of miRNA-375 and miRNA-200c were analyzed by RT-qPCR. Allogenic peripheral blood mononuclear cells were cultured with islets. T cell and monocyte activation were monitored by flow cytometry. Cytokine and miRNA levels in culture supernatant were measured by Luminex assay and RT-qPCR respectively. Results: The presence of TAK-242 in soluble form as well as released by cleavable linker from islet surface significantly reduced the release of miRNA-375 (p<0.01) and miRNA-200c (p<0.01) indicating less islet damage. In allogenic co-culture of islets and PBMCs, TAK-242 inhibited the expression of CD69 in T cells as well as decreased (p<0.05) the expression of CD86 and CD80 in monocytes. The production of cytokines IL-1β (p<0.001), IL-6 (p=0.01), IL-8 (p<0.05), IP10 (p<0.05), MCP-1 (p<0.001) and TNFα (p=0.005) in culture supernatant was decreased in the presence of soluble TAK-242 as well as TAK-242 released from islet surfaces. Conclusions: Inhibition of TLR4 using small molecule, TAK-242, protected islets from innate damage due to IBMIR as well as adaptive responses of activation of T cells and monocytes. These results validate the future study of inhibition of TLR4 using in vivo transplant model(s) to further investigate the efficacy of TLR4 inhibition to improve islet transplant survival and function. Disclosure J.D.Mattke: None. B.Naziruddin: None. B.Kane: None.