Activation of Hippo/YAP signaling pathway exacerbates vascular remodeling and aggravates hypertension by upregulating...

The Hippo/YAP signaling pathway is closely related to the occurrence and development of cardiovascular diseases. However, it's still unclear whether this pathway plays a certain role in hypertension. In this study, aortic morphology and function in spontaneously hypertensive rats (SHR) were comprehensively evaluated using Wistar-Kyoto rats (WKY) as controls. Results indicated that the aorta of SHRs have distinct changes in pathological structure. Furthermore, the proliferative activity of vascular smooth muscle cells (VSMCs) was enhanced, with vascular fibrosis being aggravated. Immunohistochemical analysis revealed that SHRs exhibited high expression of Yes-Associated Protein (YAP). Western Blot analysis showed that cytoplasmic YAP and TAZ expression decreased in hypertensive rats, indicating that YAP/TAZ nuclear transfer increased and Hippo/YAP signaling pathway had been activated. The cell function experiments of VSMCs extracted from rat aorta showed that the cell viability and proliferation ability of VSMCs in SHRs were enhanced, the expression of Fibronectin and collagen I was increased, and vascular fibrosis was aggravated. siRNA-YAP (si-YAP) can reverse the above phenomenon in VSMCs. Knockdown of YAP can inhibit Foxm1 expression. As an inhibitor of large tumor suppressor kinases LAST1/2, GA-107 can inhibit the phosphorylation level of YAP, increase blood pressure, aggravate aortic pathomorphological changes, promote VSMCs proliferation and vascular fibrosis, and thus aggravate hypertension symptoms in SHRs. However, these effects of GA-107 can be antagonized by inhibiting Foxm1 with thiosulfathiazole (Thio). Conclusively, Hippo/YAP signaling pathway promotes vascular remodeling through the regulation of Foxm1 and causes hypertension.