机构：[1]Inner Mongolia Key Laboratory of Hypoxic Translational Medicine, Baotou Medical College, Baotou, Inner Mongolia Autonomous Region, China[2]Biomedicine Research Center, Basic Medical College and Baotou Medical College of Neuroscience Institute, Baotou Medical College, Baotou, Inner Mongolia Autonomous Region, China[3]Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China科技平台低氧适应转化医学北京市重点实验室首都医科大学宣武医院[4]Department of Oral and Maxillofacial Surgery, University of California San Francsico, San Francisco, CA, USA[5]Department of Neurosurgery, the First Affiliated Hospital of Baotou Medical College, Baotou, Inner Mongolia Autonomous Region, China
Hypoxic preconditioning has been shown to improve hypoxic tolerance in mice, accompanied by the downregulation of DNA methyltransferases (DNMTs) in the brain. However, the roles played by DNMTs in the multiple neuroprotective mechanisms associated with hypoxic preconditioning remain poorly understood. This study aimed to establish an in vitro model of hypoxic preconditioning, using a cultured mouse hippocampal neuronal cell line (HT22 cells), to examine the effects of DNMTs on the endogenous neuroprotective mechanisms that occur during hypoxic preconditioning. HT22 cells were divided into a control group, which received no exposure to hypoxia, a hypoxia group, which was exposed to hypoxia once, and a hypoxic preconditioning group, which was exposed to four cycles of hypoxia. To test the ability of hypoxic preadaptation to induce hypoxic tolerance, cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-5(3-carboxymethonyphenol)-2-(4-sulfophenyl)-2H-tetrazolium assay. Cell viability improved in the hypoxic preconditioning group compared with that in the hypoxia group. The effects of hypoxic preconditioning on the cell cycle and apoptosis in HT22 cells were examined by western blot assay and flow cytometry. Compared with the hypoxia group, the expression levels of caspase-3 and spectrin, which are markers of early apoptosis and S-phase arrest, respectively, noticeably reduced in the hypoxic preconditioning group. Finally, enzyme-linked immunosorbent assay, real-time polymerase chain reaction, and western blot assay were used to investigate the changes in DNMT expression and activity during hypoxic preconditioning. The results showed that compared with the control group, hypoxic preconditioning downregulated the expression levels of DNMT3A and DNMT3B mRNA and protein in HT22 cells and decreased the activities of total DNMTs and DNMT3B. In conclusion, hypoxic preconditioning may exert anti-hypoxic neuroprotective effects, maintaining HT22 cell viability and inhibiting cell apoptosis. These neuroprotective mechanisms may be associated with the inhibition of DNMT3A and DNMT3B.
基金：
National Natural Science Foundation of China, Nos. 81460283 (to GS), 81660307 (to GS), 31860307 (to WX); the Science Foundation of Inner Mongolia Autonomous Region of China, Nos. 2018LH08078 (to GS), 2018LH03029 (to JHS); the Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region of China, No. NJYT-18-B26 (to WX); the Scientific Research Foundation of Baotou Medical College of China, Nos. BYJJ-YF 201717 (to SCY), BYJJ-YF 201606 (to WX); the National Key Research and Development Program of China, No. 2017YFC1308405 (to GS).
第一作者机构：[1]Inner Mongolia Key Laboratory of Hypoxic Translational Medicine, Baotou Medical College, Baotou, Inner Mongolia Autonomous Region, China[2]Biomedicine Research Center, Basic Medical College and Baotou Medical College of Neuroscience Institute, Baotou Medical College, Baotou, Inner Mongolia Autonomous Region, China[3]Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
通讯作者：
推荐引用方式(GB/T 7714)：
Na Liu,Xiao-Lu Zhang,Shu-Yuan Jiang,et al.Neuroprotective mechanisms of DNA methyltransferase in a mouse hippocampal neuronal cell line after hypoxic preconditioning.[J].NEURAL REGENERATION RESEARCH.2020,15(12):2362-2368.doi:10.4103/1673-5374.285003.
APA：
Na Liu,Xiao-Lu Zhang,Shu-Yuan Jiang,Jing-Hua Shi,Jun-He Cui...&Guo Shaop.(2020).Neuroprotective mechanisms of DNA methyltransferase in a mouse hippocampal neuronal cell line after hypoxic preconditioning..NEURAL REGENERATION RESEARCH,15,(12)
MLA：
Na Liu,et al."Neuroprotective mechanisms of DNA methyltransferase in a mouse hippocampal neuronal cell line after hypoxic preconditioning.".NEURAL REGENERATION RESEARCH 15..12(2020):2362-2368
