Stimulator of Interferon Genes Deletion in Primary Heart Endothelial Cells Results in Decreased T Cell Transmigration

Abstract

The vascular endothelium is a major regulator of immune responses following injury and organ specific inflammation, in part by actively participating in adhesion and subsequent transendothelial migration (TEM) of leukocytes from the blood stream into tissues. Stimulator of Interferon genes (STING) acts as a cytosolic DNA sensor as well as an adaptor molecule for type I interferon signaling. STING is also an important regulator of paracrine inflammatory responses, effectively functioning as a “signaling hub” molecule. Our current data shows that primary mouse heart endothelial cells (MHEC) express STING, and we tested the hypothesis that heart endothelial STING modulates leukocyte adhesion and/or TEM. C57BL/6 WT and STING‐deficient MHEC were isolated from mouse hearts using positive selection and were grown to confluency in vitro. Upon confluency the monolayers were stimulated with TNFα to induce adhesion molecule upregulation. Activated Th1 cells were generated in vitro by positively selecting CD4+ cells from WT spleen and inguinal lymph nodes and stimulating them with a Th1‐specific cocktail. Th1 cells were then perfused across TNFα‐activated primary MHEC. Adhesion, TEM, and total accumulated cells (adhered plus TEM) under defined laminar flow conditions were analyzed by real time videomicroscopy using a parallel plate flow chamber. STING‐deficiency in MHEC resulted in decreased T cell TEM, even in the presence of strong chemokine stimulation but did not alter accumulation. This phenotype correlated with marginally decreased expression of ICAM‐1 in the STING‐deficient TNFα‐treated MHEC. RNA‐sequencing analysis of WT and STING‐deficient MHEC indicated further differences between the groups, particularly in respect to immune‐related genes and genes coding for endothelial cell adhesion molecules that play a role in leukocyte recruitment and TEM. Ongoing studies will determine the contribution of heart endothelial STING to leukocyte recruitment and TEM in vivo and dissect the mechanisms regulating the heart endothelial STING‐mediated innate sensing upon inflammation.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.