The Molecular Mechanism Of Mitochondrial P53 Translocation Activated By Pin1 During Heat Stress Induced Vascular Endothelial Cells Apoptosis

Background and AimsOur preliminary study has revealed that heat stress-induced vascular endothelial cells apoptosis is associated with translocation of p53 to mitochondrial induced by ROS(Transcription-independent p53 apoptosis).Previous studies have suggested that Pinl could regulate p53 function through specific binding of p53 phosphorylation sites.Based on these studies,we presumed that Pinl regulate mitochondrial p53 translocation during ROS-p53 transcription-independent apoptosis activated by heat stress.So that we can profound understanding of the mechanism of endothelial dysfunction induced by heat stress and hope to reduce the mortality and morbidity of heat stroke.Methods and Results1.Heat stress-induced p53 transcription-independent pathway was involved in vascular endothelial cells apoptosisMice aortic endothelial cells(MAEC)were isolated from wide type mice and p53KO mice and named MAEC p53+/+ and MAEC p53-/-cells,respectively.Meanwhile,MAEC p53 nuclear input site mutation cell model(MAEC p53NLS cells)was constructed.Results showed that heat stress-induced p53 translocation to mitochondrial,mitochondrial membrane potential damage,Cyt C release from mitochondrial to cytoplasmic,and Caspase-9/-3 activation and occurrence of apoptosis in both MAEC p53+/+ and MAEC p53NLS cells.In vivo,heat stress also induced p53 transcription-independent apoptosis in aorta endothelial.What’s more,the damage degree of MAEC p53-/-cells and p53 KO mice was significantly lower than that of MAEC p53+/+ cells and aortic endothelial after heat stress.2.Heat stress-induced p53 transcription-independent apoptosis pathway was regulated by Pinl through binding to p53 Ser46 phosphorylation siteHeat stress led to p53 S46 phosphorylation,increased Pin1 expression activity,and the interaction with p53 in endothelial.MAEC p53+/+ cells over-expression or interference with Pin1 could promote or inhibit heat stress-induced p53 transcription-independent apoptosis pathway.Using Pinl inhibitor Juglone to pre-treat with wild type mice or interfere with Pin1 expression in MAEC p53+/+cells,it significantly inhibited heat stress-induced p53 transcription-independent apoptosis pathway in both MAEC p53+/+cells and aortic endothelial.In addition,heat stress also induced p53 transcription-independent apoptosis pathway in H1299 p53NLS cells(H1299 p53-/-cells transfected with p53 nuclear mutant input site construction),which was consistent with heat stress-induced apoptosis activation pathway in endothelial cells.What’s more,H1299 p53NLS cells only mutated p53 S46 phosphorylation site could inhibit heat stress-induced p53 transcription-independent apoptosis pathway,and the weak apoptotic activity of p53NLS S46A could not be potentiated by overexpression of Pin1.3.ROS as an upstream was involved in Pin1/p53 transcription-independent apoptosis pathway in vascular endothelial cells injury induced by heat stressHeat stress increased mitochondrial ROS(O2-·)in MAEC p53+/+ cells,and led to oxidative stress response in aortic endothelium.MAEC p53+/+ cells over-expression with MnSOD or using ROS(O2-·)inhibitor MnTBAP to pre-treat with wild type mice,it significantly inhibited heat stress-induced Pin1 expression and activity,mitochondrial p53 translocation,and the interaction with Pinl and p53.What’s more,it also inhibited heat stress induced Pinl/p53 transcription-independent apoptosis pathway in both MAEC p53+/+cells and aortic endothelial.Conclusions1.Heat stress-induced the activation of p53 transcription-independent apoptosis pathway in both endothelial cells and aortic endothelium.Knockout p53 gene can reduce heat stress-induced aortic endothelium injury and vascular endothelial cells apoptosis.2.Pinl through binding to p53 S46 phosphorylation site to promote heat stress-induced p53 transcription-independent apoptosis pathway.3.ROS as an upstream through enhanced the interaction with Pinl and p53,promoted heat stress induced Pinl/p53 transcription-independent apoptosis pathway activation,which led to aortic endothelium injury and vascular endothelial cells apoptosis.