The combination of G9a histone methyltransferase inhibitors with erythropoietin protects heart against damage from acute myocardial infarction

Pei-Hsun Sung; Chi-Wen Luo; John Y Chiang; Hon-Kan Yip

The combination of G9a histone methyltransferase inhibitors with erythropoietin protects heart against damage from acute myocardial infarction

Am J Transl Res. 2020 Jul 15;12(7):3255-3271. eCollection 2020.

Authors

Pei-Hsun Sung^{1

2}, Chi-Wen Luo^{3

4}, John Y Chiang^{5

6}, Hon-Kan Yip^{1

2

7

8

9

10}

Affiliations

¹ Division of Cardiology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine Kaohsiung 83301, Taiwan, ROC.
² Center for Shockwave Medicine and Tissue Engineering, Kaohsiung Chang Gung Memorial Hospital Kaohsiung 83301, Taiwan, ROC.
³ Department of Surgery, Kaohsiung Medical University Hospital Kaohsiung 80708, Taiwan, ROC.
⁴ Division of Breast Surgery, Department of Surgery, Kaohsiung Medical University Hospital Kaohsiung 80708, Taiwan, ROC.
⁵ Department of Computer Science and Engineering, National Sun Yat-Sen University Kaohsiung 80424, Taiwan, ROC.
⁶ Department of Healthcare Administration and Medical Informatics, Kaohsiung Medical University Kaohsiung 80708, Taiwan, ROC.
⁷ Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital Kaohsiung 83301, Taiwan, ROC.
⁸ Department of Medical Research, China Medical University Hospital, China Medical University Taichung, Taiwan 40402, ROC.
⁹ Department of Nursing, Asia University Taichung 41354, Taiwan, ROC.
¹⁰ Division of Cardiology, Department of Internal Medicine, Xiamen Chang Gung Hospital Xiamen, Fujian, China.

PMID: 32774698
PMCID: PMC7407701

Abstract

Background: This study tested the hypothesis that combined histone methyltransferase G9a inhibitor (i.e., UNC0638) and erythropoietin (EPO) was superior to either one alone for protecting myocardium from acute myocardial infarction (AMI) damage.

Methods and results: Adult-male SD rats (n=30) were equally categorized into group 1 (sham-operated control), group 2 (AMI), group 3 (AMI-EPO/1000 IU/kg, I.M./3 h after AMI), group 4 (AMI- UNC0638/5 mg/kg I.P./3 h after AMI) and group 5 [AMI-UNC0638-EPO 3 h after AMI] treatment. Animals were euthanized at day 21 after AMI induction. By day 21, left-ventricular-ejection-fraction (LVEF) was highest in group 1, lowest in group 2, significantly higher in group 5 than in groups 3 and 4, but no difference between the latter two groups (all P<0.0001). The protein expressions of inflammatory (MMP-2/MM-9), fibrotic (fibronectin/Smad3/TGF-ß), apoptotic/DNA-damaged (caspas-3/PARP/γ-H2AX), cell-stress response (HIF-1α/p-Akt/p-mTOR) and autophagic (beclin-1/ratio of LC3B-II to LC3B-I) biomarkers exhibited an opposite pattern, whereas the protein expressions of endothelial integrity (CD31/vWF) and anti-oxidant (SIRT1/SIRT3) exhibited an identical pattern of LVEF among the five groups (all P<0.0001). The protein expressions (SDF-1α/VEGF/CXCR4) and cellular expressions (C-kit/CD31+//Sca-1/CD31+//KDR/CD34+) of angiogenesis biomarkers were significantly progressively increased from groups 1 to 5 (all P<0.0001). The infarction/fibrotic areas, myocyte size and number of G9a cells exhibited an opposite pattern, whereas the small-vessel density displayed an identical trend of LVEF among the groups (all P<0.0001). Flow cytometric analysis showed cellular levels of inflammation (Ly6G+/MPO+/CD11b/c+), oxidative-stress (DCFDA+) and apoptosis (early+/late+) exhibited an opposite pattern to LVEF among the groups (all P<0.0001).

Conclusion: EPO-BIX01294 effectively protected myocardium against AMI-induced damage.

Keywords: Acute myocardial infarction; G9a inhibitor; apoptosis; fibrosis; histone methyltransferase; inflammation; oxidative stress.