KLF4 recruits SWI/SNF to increase chromatin accessibility and reprogram the endothelial enhancer landscape under laminar shear stress.

Physiologic laminar shear stress (LSS) induces an endothelial gene expression profile that is vasculo-protective. In this report, we delineate how LSS mediates changes in the epigenetic landscape to promote this beneficial response. We show that under LSS, KLF4 interacts with the SWI/SNF nucleosome remodeling complex to increase accessibility at enhancer sites that promote the expression of homeostatic endothelial genes. By combining molecular and computational approaches we discover enhancers that loop to promoters of KLF4- and LSS-responsive genes that stabilize endothelial cells and suppress inflammation, such as BMPR2, SMAD5, and DUSP5. By linking enhancers to genes that they regulate under physiologic LSS, our work establishes a foundation for interpreting how non-coding DNA variants in these regions might disrupt protective gene expression to influence vascular disease. Here the authors studied pulmonary arterial endothelial cells (PAEC) under laminar shear stress and show that this physiologic condition markedly changes chromatin accessibility at regulatory regions, when compared to cells grown in a static state. They find that KLF4 organizes chromatin by interacting with the SWI/SNF nucleosome remodeling complex to regulate vasculo-protective gene expression. [ABSTRACT FROM AUTHOR]