Regulation of YAP Promotor Accessibility in Endothelial Mechanotransduction
Endothelial cells (ECs) are constantly exposed to mechanical forces in the form of fluid shear stress, extracellular stiffness, and cyclic strain. How mechanical forces are transduced to the nucleus to drive transcriptional reprogramming in ECs is poorly understood. The mechanoresponsive activity of Yes associated protein (YAP) and its role in vascular development are well described, however, whether changes to transcription or epigenetic regulation of YAP are involved in these processes remains unanswered. Our results reveal that mechanical forces sensed at cell-cell junctions by the YAP target gene, Angiomotin-like 2 (AmotL2), are directly intervened into changes in global chromatin accessibility and EZH2 activity leading to modulation of YAP-promotor activity. Functionally, shear stress induced proliferation of ECs in vivo were reliant on AmotL2 and YAP/TAZ endothelial expression. Mechanistically, uncoupling of the nuclear-cytoskeletal connection from junctions and focal adhesions led to altered nuclear morphology, chromatin accessibility and suppression of YAP-promotor activity. Our findings reveal a role for AmotL2 and nuclear-cytoskeletal force transmission in modulating the epigenetic and transcriptional regulation of YAP to maintain a mechanoenforced positive-feedback loop of vascular homeostasis. Overall design: Bulk ATAC-seq from HUVEC and HUAEC cells transduced with shScr or shAmotL2 lentivirus with 4 replicates per condition to investigate the role of AmotL2 in regulating chromatin accessibility