Exploring Human NK Cell Function and Activation by Endothelium via P-STAT5 and HuR regulation 2254028

Introduction Natural killer (NK) cells circulate in the blood in a poised but inactive state and can be further primed by activating signals to acquire enhanced cytotoxicity and secretion of pro-inflammatory cytokines such as IFN-γ, and TNF-α. We hypothesize that NK cells can be primed by migration through endothelial cells (ECs) as they enter graft or tumor tissue. Methods Nk cell isolation, Flow cytometry. Trans-endothelial migation assay. Results We observed that isolated human blood NK cells will undergo trans-endothelial migration (TEM) through IL-1β-activated but not resting EC monolayers over 60 minutes. Human peripheral blood NK cells showed a rapid rise of P-STAT5 in 20-30 minutes and elevated synthesis of TNF-α and Granzyme B after 4-5 days of coculture. IL-15-induced increases of P-STAT5 was inhibited by an anti—IL-15 antibody. Furthermore, we are exploring whether the increased TNF-α and IFN-γ synthesis is inhibited by a pharmacological blocker of HuR binding to their mRNAs. Conclusion Elucidating key molecular interactions at the endothelial interface that govern NK cell behavior has potential implications for therapeutic modulation.