Sp1 Targeted PARP-1 Inhibition Protects Cardiomyocytes from Myocardial Reperfusion Injury via Downregulation of Autophagy

Background: Myocardial reperfusion injury(MRI),characterized by post-ischemic cardiomyocytes death and post reperfusion myocardial damage, is a common yet fatal clinical complication remains to be solved. Previous studies have demonstrated that poly(ADP-ribose) polymerase-1(PARP-1) participates in the progression of various cardiovascular diseases, but whether it is involved in MRI is unknown. Therefore, this research was conducted to explore the role and mechanism of PARP-1 in the development of MRI. Methods: In vitro, oxygen glucose deprivation / reperfusion (OGD/R) was used to stimulate MRI induced myocardial autophagy; Animal model of MRI was established by ligating the rats’ left anterior descending coronary artery and then reperfused in vivo; Real-time PCR, western blot, GFP LC3 detection, flow cytometry, MTT analysis, ChIP, dual-luciferase reporter assay, immunofluorescence microscopy, electrocardiogram, echocardiography, H&E staining, masson’s trichrome staining and TUNEL assay were used to confirm the role and mechanism of PARP-1 in MRI. Findings: We discovered that PARP-1 was activated by MRI induced myocardial autophagy. Moreover,PARP-1 inhibition can protect cardiomyocytes from MRI through inhibition of autophagy.Next,we demonstrated that Specificity protein 1(Sp1) was a transcription factor of PARP-1,and it can regulate the target gene of PARP-1 through binding to its target gene promoter during trancription; additonally, silencing Sp1 can prevent cardiomyocytes from MRI. Finally,we verified that it was via PARP-1 inhibition that Sp1 suppression prevented cardiomyocytes from MRI. Interpretation: This is the first study indicating that PARP-1 inhibition protects cardiomyocytes from myocardial reperfusion injury through inhibition of autophagy, which is targeted by Sp1 suppression. The utilization of PARP-1 may be a therapeutic target for MRI in the future. Funding Statement: This research was supported by fund from Shanghai Jiaotong University (No:0507N14008) and from Shanghai Natural Science Foundation(No:17ZR1422200). Declaration of Interests: The authors declared that they have no conflicts of interest to this work. Ethics Approval Statement: All animal studies were conducted in compliance with the guidelines from Directive 2010/63/EU of the European Parliament on the protection of animals used for scientific purposes or the NIH Guide for the Care and Use of Laboratory Animals and Use Committee of Shanghai General Hospital Affiliated to Shanghai Jiao Tong University(Permission Number: SYXK (Su) 2017–0007).The animal procedures were approved by Shanghai Jiao Tong University School of Medicine, the Animal Care and Use Committee.