Effect Of TRPV4-eNOS Complex On Vascular Function In Hypertensive Models

The endothelium forms a barrier between the blood vessels and the vessel wall to maintain vascular homeostasis.The shear stress generated by blood flow can cause endothelial cells to convert mechanical stimuli into biochemical signals within the cells,and thus,dysfunction is associated with various diseases including hypertension.Shear stress-induced vasodilation to maintain vascular tone is the primary physiological function of the transient receptor potential vanilloid 4?TRPV4?channel.Endothelial nitric oxide synthase?eNOS?is widely expressed in endothelial cells,and its nitric oxide?NO?catalyzed by L-arginine is an important vasodilator.Therefore,from the perspective of TRPV4-eNOS functional complex,it is of great significance to study its intervention on vascular function and provide new ideas and methods for effective treatment of hypertension.In this paper,two models of hypertension were first constructed in mice,using 8%high salt induction and Ang II sustained release induction.The high salt-induced hypertensive model takes 1 month and the blood pressure can reach 120 mmHg.It takes two weeks for Ang II to induce hypertension and the blood pressure can reach 140 mmHg.The hypertensive models were constructed by these two methods as a pathological model to provide conditions for subsequent experiments.The immunofluorescence resonance energy transfer method was used to demonstrate the physical coupling between TRPV4 and eNOS in thoracic aortic endothelial cells,and the coupling efficiency decreased by 66.54%in the high salt-induced hypertensive model.In the Ang II induced hypertensive model,The coupling efficiency has dropped by 60.12%.The method of co-immunoprecipitation further validates this conclusion.The results showed that the TRPV4-eNOS complex was down-converted under the hypertensive models.Based on the down-regulation of physical coupling of TRPV4 with eNOS in endothelial cells of hypertensive models,we investigated changes in functional coupling between endothelial cells.When the TRPV4 agonist GSK1016790A was added to the control group,the fluorescence intensity was significantly increased,that is,the calcium ion concentration was significantly increased.However,the increase in fluorescence intensity caused by the addition of GSK1016790A to endothelial cells of the hypertensive models was significantly lower than that of the control group.Under high salt induction and Ang II induction,the fluorescence intensity decreased by 42.11%and 53.67%,respectively.Studies have shown that eNOS activity is dependent on calcium ion concentration.Further studies in two models have found that NO production is reduced,indicating that inhibition of TRPV4 in hypertensive models leads to decreased Ca²⁺influx in thoracic aortic endothelial cells,resulting in decreased eNOS activity.This leads to a decrease in the production of NO,and the functional coupling of TRPV4 and eNOS is reduced.In addition to studying the interaction between TRPV4 and eNOS at the cellular level,this topic further explores the relationship between the two at the thoracic aorta.The experimental method of immunofluorescence energy resonance transfer found that the physical coupling of the TPRV4-eNOS complex at the tissue level was also down-regulated in the hypertensive models.The myograph experimental method found that the dilated thoracic aorta in both hypertensive models showed diastolic abilities in both Ach and GSK-mediated dilation.The mechanism of Ach-mediated relaxation is through activation of M-choline receptors,increased NO release,and vasodilation;whereas GSK-mediated relaxation increases Ca²⁺influx through TRPV4,increases eNOS activity,and increases NO production,vasodilation.Both Ach and GSK-mediated relaxation were decreased in the hypertensive model,and the decrease in physical coupling in combination with the TPRV4-eNOS complex indicated that the functional coupling of the complex was also decreased.In summary,the physical coupling efficiency of TRPV4-eNOS in the hypertensive models was found to be decreased at the cellular and tissue levels.It is speculated that the down-regulation of the coupling ability caused by endothelial injury has a certain effect on vascular function.Therefore,based on the functional coupling of the physical coupling of the TRPV4-eNOS complex in the hypertensive models,we found that hypertension inhibits TRPV4,reduces eNOS activity and then NO reduction in production,in addition to studies in vascular function,found that vasodilation was downregulated.Therefore,from the perspective of the TRPV4-eNOS complex of the thoracic aortic endothelium,we study the effects of physical and functional coupling changes on vascular function,and provide new targets and treatment ideas for the treatment of hypertension.