Vitamin D Attenuates Ischemia/Reperfusion-Induced Cardiac Injury by Reducing Mitochondrial Fission and Mitophagy

Tzu-Lin Lee; Ming-Hsueh Lee; Yu-Chen Chen; Yi-Chieh Lee; Tsai-Chun Lai; Hugo You-Hsien Lin; Lee-Fen Hsu; Hsin-Ching Sung; Chiang-Wen Lee; Yuh-Lien Chen

doi:10.3389/fphar.2020.604700

Vitamin D Attenuates Ischemia/Reperfusion-Induced Cardiac Injury by Reducing Mitochondrial Fission and Mitophagy

Front Pharmacol. 2020 Dec 10:11:604700. doi: 10.3389/fphar.2020.604700. eCollection 2020.

Authors

Tzu-Lin Lee¹, Ming-Hsueh Lee^{2

3}, Yu-Chen Chen¹, Yi-Chieh Lee¹, Tsai-Chun Lai¹, Hugo You-Hsien Lin⁴, Lee-Fen Hsu^{2

3}, Hsin-Ching Sung^{5

6}, Chiang-Wen Lee^{7

8

9}, Yuh-Lien Chen¹

Affiliations

¹ Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan.
² Division of Neurosurgery, Department of Surgery, Chang Gung Memorial Hospital, Chiayi, Taiwan.
³ Department of Respiratory Care, Chang Gung University of Science and Technology, Chiayi, Taiwan.
⁴ Division of Nephrology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
⁵ Department of Anatomy, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
⁶ Aesthetic Medical Center, Department of Dermatology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
⁷ Department of Nursing, Division of Basic Medical Sciences, and Chronic Diseases and Health Promotion Research Center, Chang Gung University of Science and Technology, Chiayi, Taiwan.
⁸ Research Center for Industry of Human Ecology and Research Center for Chinese Herbal Medicine, Chang Gung University of Science and Technology, Taoyuan, Taiwan.
⁹ Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, Chiayi, Taiwan.

Abstract

Myocardial infarction is the leading cause of morbidity and mortality worldwide. Although myocardial reperfusion after ischemia (I/R) is an effective method to save ischemic myocardium, it can cause adverse reactions, including increased oxidative stress and cardiomyocyte apoptosis. Mitochondrial fission and mitophagy are essential factors for mitochondrial quality control, but whether they play key roles in cardiac I/R injury remains unknown. New pharmacological or molecular interventions to alleviate reperfusion injury are currently considered desirable therapies. Vitamin D₃ (Vit D₃) regulates cardiovascular function, but its physiological role in I/R-exposed hearts, especially its effects on mitochondrial homeostasis, remains unclear. An in vitro hypoxia/reoxygenation (H/R) model was established in H9c2 cells to simulate myocardial I/R injury. H/R treatment significantly reduced H9c2 cell viability, increased apoptosis, and activated caspase 3. In addition, H/R treatment increased mitochondrial fission, as manifested by increased expression of phosphorylated dynein-related protein 1 (p-Drp1) and mitochondrial fission factor (Mff) as well as increased mitochondrial translocation of Drp1. Treatment with the mitochondrial reactive oxygen species scavenger MitoTEMPO increased cell viability and decreased mitochondrial fission. H/R conditions elicited excessive mitophagy, as indicated by increased expression of BCL2-interacting protein 3 (BNIP3) and light chain (LC3BII/I) and increased formation of autolysosomes. In contrast, Vit D₃ reversed these effects. In a mouse model of I/R, apoptosis, mitochondrial fission, and mitophagy were induced. Vit D₃ treatment mitigated apoptosis, mitochondrial fission, mitophagy, and myocardial ultrastructural abnormalities. The results indicate that Vit D₃ exerts cardioprotective effects against I/R cardiac injury by protecting mitochondrial structural and functional integrity and reducing mitophagy.

Keywords: apoptosis; cardiac ischemia/reperfusion; mitochondrial fission; mitophagy; vitamin D3.