The primary objective of this current proposal is to determine the mechanism by which the LRRC8a regulates endothelium dependent vasorelaxation and blood pressure. In order to test the above hypothesis of LRRC8a, there will be two specific aims that will be analyzed for the research. It is the investigation of the LRRC8a-p66shc-PI3K-AKT-eNOS signaling in endothelium. For this, there should be analysis of the LRRC8a for activation of PI3K-AKT-eNOS and for the suppression of the p66shc pathway. This is done by measuring i pAKT1, pAKT2, AKT1, AKT1, p-eNOS, eNOS, and p-p66shc +/- LRRC8a +/- p66shc under basal resting conditions and in response to endothelial cell stretching on deformable membranes using the FlexCell System. Subsequently, there will be experimentation on HUVEC and in arterial endothelial cells +/- Ad-shSCR/LRRC8a +/- RNAi for p66shc. Added to this the primary cultures of aortic endothelial cells will be isolated from WT and endothelial LRRC8a KO of mice and transgenic mice over expressing shRNA to p66shc. From this, there will be determination made about the LRRC8a forms a molecular complex with p66shc. This is done by co-immunoprecipitation and co-localization studies in endothelial cells.
The second aim of this research is to understand the underlying implication of the LRRC8a on blood pressure by analyzing the endothelial cell. In this sceaniro, there should be measurement of the blood pressure in WT and the LRRC8a KO mice endothelial cells should be measures. For this, there will be measurement of the baseline, Angiotensin-II infusion via osmotic mini-pumps. Osmotic mini-pumps will be used to induce conditions of hypertension. Blood pressure will be measured by using Tail-cuff BP measurement and implantable aortic BP telomeres. If it is observed that LRRC8a KO mice develop HTN then they will be cross analyzed with p66shcRNAi mice. This p66shcRNAi mouse is found to have a global knockdown of p66shc. This is done to determine if this phenotype can be found in LRRC8a KO/p66shcRNAi mice. Subsequent to this analysis the vascular reactivity studies on explanted aortas, immunostaining of p-eNOS, eNOS, pAKT1, pAKT2, AKT1, AKT2, p-p66shc will be done. This would then be and quantified with endothelial NO and oxidants. Fluorescence and chemiluminescence methodologies will be performed. Previous literature of endothelial VRAC has been analyzed over the past 16 years. There is a considerable lack of knowledge about the ion channels. Using the adenoviral shRNA-mediated LRRC8a knock-down it can be established that LRRC8a is required for the volume-regulated anion current (VRAC) in human umbilical vein endothelial cells