Mechanical Regulation of Transient Receptor Potential Vanilloid 4 Function in Aging and Cardiovasculature Disease

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Vascular aging is characterized by progressive deterioration of blood vessel structure and function and is associated with increased vascular stiffness, endothelial dysfunction, and chronic inflammation. However, the molecular mechanisms underlying vascular stiffening and endothelial mechanotransduction remain incompletely understood. Mechanosensitive ion channels are key upstream regulators of vascular cell responses to biomechanical cues. Among these, transient receptor potential vanilloid 4 (TRPV4), a calcium-permeable ion channel expressed in endothelial cells, plays important roles in vascular physiology; however, its role in regulating endothelial responses to vascular stiffness is not defined. Here, we utilize a previously developed microfluidic model of vascular stiffening to investigate how substrate stiffness and shear stress interact to regulate endothelial TRPV4 expression and function.We found that under static conditions, increased substrate stiffness downregulates TRPV4 expression and attenuated TRPV4-mediated calcium responses in endothelial cells. In contrast, exposure to high shear stress enhances TRPV4 sensitivity to its selective agonist in a stiffness-dependent manner, suggesting that hemodynamic forces modify the effect of stiffness on TRPV4 function. Consistent with this shear-stress-dependent response, immunohistochemical analysis of human aortic tissues stratified by vascular stiffness demonstrates increased endothelial TRPV4 expression in stiff compared with soft aortas. Furthermore, TRPV4 activation regulated stiffness-dependent actin remodeling, endothelial alignment, and cell elongation. Pharmacological inhibition of TRPV4 using GSK2193874 increased endothelial inflammatory responses, supporting a protective role for TRPV4 in endothelial adaptation to pathological mechanical environments.Collectively, these findings highlight TRPV4's contribution to endothelial responses to vascular stiffening and its potential as a therapeutic target for vascular aging and cardiovascular diseases.

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