The Role Of TRPV4 In Vascular Functional Homeostasis

Vascular endothelial cells play an important role in the regulation of vascular function.Cardiovascular diseases such as obesity and hypertension can led to imbalance of the reactive oxygen species(ROS)homeostasis in the vascular endothelial cells,which in turn leads to the increase in vascular permeability.Therefore,targeting TRPV4-Nox2 complex to regulate ROS homeostasis,we may provide new strategies and targets for therapy of obesity.Firstly,we used the primary mouse endothelial cells(MAECs)to confirm the existence of TRPV4 and Nox2 in MAECs by RT-PCR and Western Blot.Physical interaction of TRPV4 and Nox2 was further examined by co-IP and immune-FRET assays.In the high-fat(FFA)cell model,TRPV4-Nox2 coupling was increased.Then,the DCFH-DA and Mito-SOX fluorescent probes were used to label ROS.As a result,ROS was increased in FFA cells,and TRPV4 inhibitor HC067047 A or the Nox2 inhibitor Apocynin(Apo)could reverse the increase in ROS;Secondly,the protein expression of VE-cadherin was significantly decreased,and the ICAM-1 expression was increased in FFA cells.Next,by using rhodamine-phalloidin and FITC-dextran,we found that stress fibre formation and endothelial leakage were increased in FFA cells.Moreover,the mitochondrial membrane potential was significantly decreased in FFA cells.Our results demonstrated that the increase in ROS production can further promote cell permeability,whereas TRPV4 inhibitors and Nox2 inhibitors can reverse this damage.Finally,we used TRPV4 WT and KO mice fed with high fat diet to induce DIO mouse models.The immuno-FRET demonstrated that the TRPV4-Nox2 coupling was increased in DIO-TRPV4 WT mice;Further,by using en face ROS production and Miles Assay,we found DIO increases ROS production,and then the increase in ROS promotes vascular permeability.Taken together,our results demonstrated that the existence and interaction of TRPV4 and Nox2 in MAECs.Under the pathological model of obesity,the increase in TRPV4-Nox2 coupling can mediate ROS production and vascular dysfunction.Therefore,the TRPV4-Nox2 coupling can be used as a target to mediate imbalance of ROS homeostasis and provide new strategies for the therapy of obesity and other cardiovascular diseases.