NR4A1 contributes to high-fat associated endothelial dysfunction by promoting CaMKII-Parkin-mitophagy pathways

• DOI: 10.1007/s12192-018-0886-1
• Publication Date: 2018-02-22T06:29:42Z
• Authors: Pei Li; Yuzhi Bai; Xia Zhao; Tian Tian; Liying Tang; Jing Ru; Yun An; Jing Wang
• Keywords: 0301 basic medicine; Ubiquitin-Protein Ligases; Mitophagy; Endothelial Cells; Apoptosis; Atherosclerosis; Diet, High-Fat; Mitochondria; Mice; 03 medical and health sciences; Nuclear Receptor Subfamily 4, Group A, Member 1; Animals; Endothelium, Vascular; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Energy Metabolism; Signal Transduction

Parkin-related mitophagy is vital for endothelial cell viability and the development of atherosclerosis, although the upstream regulatory factor underlying Parkin-mediated mitophagy in endothelial apoptosis and atherosclerosis progression remains unknown. In the present study, we demonstrated that nuclear receptor subfamily 4 group A member 1 (NR4A1) is actually expressed in aortic endothelial cells (AECs) under oxidized low-density lipoprotein (ox-LDL) treatment in vitro or isolated from high-fat treated mice in vivo. Higher NR4A1 levels were associated with AEC apoptosis, mitochondrial dysfunction, and energy disorder. At the molecular level, ox-LDL stimulation increased NR4A1 expression, which evoked Parkin-mediated mitophagy. Excessive mitophagy overtly consumed mitochondrial mass, leading to an energy shortage and mitochondrial dysfunction. However, loss of NR4A1 protected AECs against ox-LDL induced apoptosis by inhibiting excessive mitophagy. Furthermore, we also identified that NR4A1 regulated Parkin activation via post-transcriptional modification by Ca2+/calmodulin-dependent protein kinase II (CaMKII). Activated CaMKII via NR4A1 induced the phosphorylated activation of Parkin. In summary, our data support the role of NR4A1/CaMKII/Parkin/mitophagy in AEC apoptosis and atherosclerosis formation and provide new insights into treating atherosclerosis with respect to endothelial viability, mitophagy, and NR4A1.