Exosomal MicroRNA-126 from RIPC Serum Is Involved in Hypoxia Tolerance in SH-SY5Y Cells by Downregulating DNMT3B

Junhe Cui; Na Liu; Zhehan Chang; Yongsheng Gao; Mulan Bao; Yabin Xie; Wenqiang Xu; Xiaolei Liu; Shuyuan Jiang; You Liu; Rui Shi; Wei Xie; Xiaoe Jia; Jinghua Shi; Changhong Ren; Kerui Gong; Chunyang Zhang; Rengui Bade; Guo Shao; Xunming Ji

doi:10.1016/j.omtn.2020.04.008

Exosomal MicroRNA-126 from RIPC Serum Is Involved in Hypoxia Tolerance in SH-SY5Y Cells by Downregulating DNMT3B

Mol Ther Nucleic Acids. 2020 Jun 5:20:649-660. doi: 10.1016/j.omtn.2020.04.008. Epub 2020 Apr 25.

Authors

Junhe Cui¹, Na Liu¹, Zhehan Chang¹, Yongsheng Gao², Mulan Bao², Yabin Xie¹, Wenqiang Xu², Xiaolei Liu², Shuyuan Jiang², You Liu², Rui Shi², Wei Xie², Xiaoe Jia², Jinghua Shi¹, Changhong Ren³, Kerui Gong⁴, Chunyang Zhang⁵, Rengui Bade⁶, Guo Shao⁷, Xunming Ji⁸

Affiliations

¹ Inner Mongolia Key Laboratory of Hypoxic Translational Medicine, Baotou Medical College, Inner Mongolia, PRC; Biomedicine Research Center, Basic Medical College and Baotou Medical College of the Neuroscience Institute, Baotou Medical College, Inner Mongolia, PRC; Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing, PRC.
² Inner Mongolia Key Laboratory of Hypoxic Translational Medicine, Baotou Medical College, Inner Mongolia, PRC; Biomedicine Research Center, Basic Medical College and Baotou Medical College of the Neuroscience Institute, Baotou Medical College, Inner Mongolia, PRC.
³ Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing, PRC.
⁴ Department of Oral and Maxillofacial Surgery, University of California San Francisco, San Francisco, CA, USA.
⁵ Department of Neurosurgery, The First Affiliated Hospital of Baotou Medical College, Inner Mongolia, China.
⁶ Inner Mongolia Key Laboratory of Hypoxic Translational Medicine, Baotou Medical College, Inner Mongolia, PRC; Biomedicine Research Center, Basic Medical College and Baotou Medical College of the Neuroscience Institute, Baotou Medical College, Inner Mongolia, PRC. Electronic address: baard415@btmc.edu.cn.
⁷ Inner Mongolia Key Laboratory of Hypoxic Translational Medicine, Baotou Medical College, Inner Mongolia, PRC; Biomedicine Research Center, Basic Medical College and Baotou Medical College of the Neuroscience Institute, Baotou Medical College, Inner Mongolia, PRC; Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing, PRC; Department of Neurosurgery, The First Affiliated Hospital of Baotou Medical College, Inner Mongolia, China. Electronic address: shao.guo.china@gmail.com.
⁸ Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing, PRC. Electronic address: jixm70@ccmu.edu.cn.

Abstract

Ischemic tolerance in the brain can be induced by transient limb ischemia, and this phenomenon is termed remote ischemic preconditioning (RIPC). It still remains elusive how this transfer of tolerance occurs. Exosomes can cross the blood-brain barrier, and some molecules may transfer neuroprotective signals from the periphery to the brain. Serum miRNA-126 is associated with ischemic stroke, and exosomal miRNA-126 has shown protective effects against acute myocardial infarction. Therefore, this study aims to explore whether exosomal miRNA-126 from RIPC serum can play a similar neuroprotective role. Exosomes were isolated from the venous serum of four healthy young male subjects, both before and after RIPC. Exosomal miRNA-126 was measured by real-time PCR. The miRNA-126 target sequence was predicted by bioinformatics software. SH-SY5Y neuronal cells were incubated with exosomes, and the cell cycle was analyzed by flow cytometry. The expression and activity of DNA methyltransferase (DNMT) 3B, a potential target gene of miRNA-126, were examined in SH-SY5Y cells. The cell viability of SH-SY5Y cells exposed to oxygen-glucose deprivation (OGD) was also investigated. To confirm the association between miRNA-126 and DNMT3B, we overexpressed miRNA-126 in SH-SY5Y cells using lentiviral transfection. miRNA-126 expression was upregulated in RIPC exosomes, and bioinformatics prediction showed that miRNA-126 could bind with DNMT3B. DNMT levels and DNMT3B activity were downregulated in SH-SY5Y cells incubated with RIPC exosomes. After overexpression of miRNA-126 in SH-SY5Y cells, global methylation levels and DNMT3B gene expression were downregulated in these cells, consistent with the bioinformatics predictions. RIPC exosomes can affect the cell cycle and increase OGD tolerance in SH-SY5Y cells. RIPC seems to have neuroprotective effects by downregulating the expression of DNMTs in neural cells through the upregulation of serum exosomal miRNA-126.

Keywords: DNA methyltransferase 3B; exosome; microRNA-126; remote ischemic preconditioning.