CYP2J2 Overexpression Improves Cardiac Dysfunction By Promoting Angiogenesis Via Jagged1/Notch1 Signaling

Background and Objective Myocardial infarction remains the most common cause of cardiac morbidity and mortality in the world,which is characterized by the sudden reduction or disruption of the coronary artery flow.The occlusion of coronary artery leads to acute and permanent ischemia of myocardium,which results in cardiomyocytes necrosis and heading into heart failure eventually.After MI,the cardiac repair is occurred due to myocardium insult,which includes a series of inflammatory response,the apoptosis of myocytes,and angiogenesis.Angiogenesis plays a vital role in repairing the injured myocardium.Impaired angiogenesis in the post-myocardial infarction and insufficient blood supply has been identified as a critical event that results in maladaptive left ventricular remodeling and accelerating heart failure progression.Although the application of advanced revascularization strategies,such as primary percutaneous coronary intervention(PCI)and coronary artery bypass surgery,which has led to a remarkable decrease in mortality rates.However,there exist some patients died or progress in heart failure.These strategies also have their inherent limitationand complication,such as the ‘no-reflow' phenomenon and postoperative vascular restenosis and occlusion.When MI occurs,the concentration of oxygen decreases,and low oxygen stimulates HIF1-? expression,which promotes endogenous angiogenesis,however,it insufficient to maintain normal myocardial blood supply.Therefore,therapeutic angiogenesis after MI plays a vital role to improve long-term prognosis and alleviate the progression of heart failure.It was well known that Cytochrome P450(CYP)epoxygenases was able to convert arachidonic acid(AA)to biologically epoxyeicosatrienoic acids(EETs),a group of cardioprotective metabolites,consisting of four regioisomers: 5,6-EET,8,9-EET,11,12-EET,and 14,15-EET,however,the primary products are 11,12-and 14,15-EET.Via the hydrolytic activity of soluble epoxide hydrolase(s EH),EETs are metabolized to dihydroxyeicosatrienoic acid(DHET),a compound that is more stable and less bioactive.The human cytochrome P450 epoxygenase,CYP2J2,is the only member of the human CYP2 J family,which expressed abundantly in coronary artery endothelial cells,smooth muscle cells,and cardiomyocytes.Previous studies had not reported the angiogenesis induced by EETs in ischemic heart failure.Hence,our studies aim to explore the influence of angiogenesis in post-MI heart failure prognosis induced by angiogenesis,at the same time,to explore the likely mechanism.Methods and Results In animal study,rats with endothelium-specific CYP2J2 overexpression driven by the tie-2 promoter and their wild-type control littermate were included in our experiment.The male rats were divided into four groups randomly,WT-Sham(n=6),TG-Sham(n=6),WT-MI(n=14),TG-MI(n=14),in which MI was induced by permanent left anteriordescending coronary,while the sham-operated group underwent a thoracotomy but did not undergo coronary artery ligation.After MI eight weeks,we firstly performed positron emission computed Tomography(PET)analyses to detect myocardial blood flow,then we conducted echocardiography and cardiac catheterization to detect left ventricular cardiac function.After catheterization measurements,we took blood sample from the carotid artery of the experimental rat.Then we get out the heart of rats and took a picture of it,some hearts were fixed in 4% paraformaldehyde for 48 hours and then embedded in paraffin.The sections were stained with haematoxylin-eosin for morphological analysis,Masson's trichrome to assess interstitial fibrosis,wheat germ agglutinin(WGA)to outline the cardiomyocytes.Some hearts were embedded in OCT compound and frozen at-80 °C to perform immunofluorescent staining,and the remaining heart tissues to perform western blotting and RT-PCR analysis.In the in vitro study,we cultured human umbilical vein endothelial cells(HUVECs)in normoxic and hypoxic conditions for 16 hours.We treated HUVECs with 11,12-EET(the main product of arachidonic acid)and its antagonist 14,15-EEZ to observe the tube formation induced by HUVECs and explore the likely mechanism.The concrete results as follows:(1)Endothelium-specific overexpression of CYP2J2 was able to decrease infarct size obviously,and decrease cardiomyocyte hypertrophy in the border zone.(2)Endothelium-specific overexpression of CYP2J2 improved cardiac function via increasing myocardial blood flow induced by angiogenesis.(3)Endothelium-specific overexpression of CYP2J2 was capable of promoting the secretion of 11,12-EET and 14,15-EET.(4)In the vitro study,11,12-EET was able to promote tube formation and increase the protein expression of VEGF-A and b FGF in normoxic and hypoxic conditions.(5)11,12-EET promoted angiogenesis via Jagged1/Notch1 signaling pathway,11,12-EET was capable of enhancing the transfer of Notch1 from the cytoplasm to the nucleus,then notch1 interacted with target proangiogenic gene.11,12-EET increased ?-secretase activity in normoxia,however,in hypoxia,11,12-EET increased nicastrin(a ?-secretase subunit)expression but did not increase ?-secretase activity.Conclusion In conclusion,CYP2J2 and EETs prevent heart failure by promoting angiogenesis via Jagged1/Notch1 signaling pathway,suggesting that CYP2J2 gene delivery or elevation of the EETs level may be a promising treatment to alleviate heart failure in post-MI.