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Homocysteine enhances neural stem cell autophagy in in vivo and in vitro model of ischemic stroke.
Cell Death Dis. 2019 07 22; 10(8):561.CD

Abstract

The elevated level of the amino acid metabolite homocysteine (Hcy) is known as a risk factor for ischemic stroke. The molecular mechanisms responsible for neurotoxicity of Hcy remain largely unknown in ischemic brains. The previous studies have shown that Hcy decreases the proliferation and viability of neural stem cells (NSCs) in vivo and in vitro. Autophagy is required for the maintenance of NSCs homeostasis. In the current study, we hypothesized that the toxic effect of Hcy on NSCs may involve the changes in autophagy level following cerebral ischemia/reperfusion injury. The results showed that Hcy reduced cell viability, increased LDH release, and induced nonapoptotic cell death in primary NSCs exposed to oxygen-glucose deprivation)/reoxygenation (OGD/R). Treatment with autophagy inhibitor 3-methyladenine (3MA) partly reversed the decrease in the viability and prevented LDH release triggered by Hcy combined with OGD/R. Increased punctate LC3 dots co-localizing with Nestin-stained NSCs were also observed in the subventricular zone of Hcy-treated MCAO animals, which were partially blocked by 3MA. In vitro studies further revealed that Hcy induced the formation of autophagosomes, markedly increased the expression of the autophagic markers and decreased p-ERK, p-PI3K, p-AKT, and p-mTOR levels. In addition, MHY1485, an activator of mTOR, reduced Hcy-induced increase in LC3 and Beclin 1 protein levels, meanwhile ERK and PI3K activators (TPA, curcumin for ERK and IGF-1 for PI3K, respectively) enhanced Hcy-triggered mTOR inhibition in OGD/R NSCs. Our findings suggest that Hcy may cause excessive autophagy by downregulation of both PI3K-AKT- and ERK- dependent mTOR signaling, thereby facilitates the toxicity of Hcy on NSCs in ischemic brains.

Authors+Show Affiliations

Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China. Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China.Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China. Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China.Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China. Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China.Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China. Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China.Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China. Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China.Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China. Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China.Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China. Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China.Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China. zhangxumei@tmu.edu.cn. Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China. zhangxumei@tmu.edu.cn.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

31332165

Citation

Wang, Mengying, et al. "Homocysteine Enhances Neural Stem Cell Autophagy in in Vivo and in Vitro Model of Ischemic Stroke." Cell Death & Disease, vol. 10, no. 8, 2019, p. 561.
Wang M, Liang X, Cheng M, et al. Homocysteine enhances neural stem cell autophagy in in vivo and in vitro model of ischemic stroke. Cell Death Dis. 2019;10(8):561.
Wang, M., Liang, X., Cheng, M., Yang, L., Liu, H., Wang, X., Sai, N., & Zhang, X. (2019). Homocysteine enhances neural stem cell autophagy in in vivo and in vitro model of ischemic stroke. Cell Death & Disease, 10(8), 561. https://doi.org/10.1038/s41419-019-1798-4
Wang M, et al. Homocysteine Enhances Neural Stem Cell Autophagy in in Vivo and in Vitro Model of Ischemic Stroke. Cell Death Dis. 2019 07 22;10(8):561. PubMed PMID: 31332165.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Homocysteine enhances neural stem cell autophagy in in vivo and in vitro model of ischemic stroke. AU - Wang,Mengying, AU - Liang,Xiaoshan, AU - Cheng,Man, AU - Yang,Liu, AU - Liu,Huan, AU - Wang,Xuan, AU - Sai,Na, AU - Zhang,Xumei, Y1 - 2019/07/22/ PY - 2019/03/05/received PY - 2019/07/03/accepted PY - 2019/06/27/revised PY - 2019/7/24/entrez PY - 2019/7/25/pubmed PY - 2020/8/4/medline SP - 561 EP - 561 JF - Cell death & disease JO - Cell Death Dis VL - 10 IS - 8 N2 - The elevated level of the amino acid metabolite homocysteine (Hcy) is known as a risk factor for ischemic stroke. The molecular mechanisms responsible for neurotoxicity of Hcy remain largely unknown in ischemic brains. The previous studies have shown that Hcy decreases the proliferation and viability of neural stem cells (NSCs) in vivo and in vitro. Autophagy is required for the maintenance of NSCs homeostasis. In the current study, we hypothesized that the toxic effect of Hcy on NSCs may involve the changes in autophagy level following cerebral ischemia/reperfusion injury. The results showed that Hcy reduced cell viability, increased LDH release, and induced nonapoptotic cell death in primary NSCs exposed to oxygen-glucose deprivation)/reoxygenation (OGD/R). Treatment with autophagy inhibitor 3-methyladenine (3MA) partly reversed the decrease in the viability and prevented LDH release triggered by Hcy combined with OGD/R. Increased punctate LC3 dots co-localizing with Nestin-stained NSCs were also observed in the subventricular zone of Hcy-treated MCAO animals, which were partially blocked by 3MA. In vitro studies further revealed that Hcy induced the formation of autophagosomes, markedly increased the expression of the autophagic markers and decreased p-ERK, p-PI3K, p-AKT, and p-mTOR levels. In addition, MHY1485, an activator of mTOR, reduced Hcy-induced increase in LC3 and Beclin 1 protein levels, meanwhile ERK and PI3K activators (TPA, curcumin for ERK and IGF-1 for PI3K, respectively) enhanced Hcy-triggered mTOR inhibition in OGD/R NSCs. Our findings suggest that Hcy may cause excessive autophagy by downregulation of both PI3K-AKT- and ERK- dependent mTOR signaling, thereby facilitates the toxicity of Hcy on NSCs in ischemic brains. SN - 2041-4889 UR - https://www.unboundmedicine.com/medline/citation/31332165/Homocysteine_enhances_neural_stem_cell_autophagy_in_in_vivo_and_in_vitro_model_of_ischemic_stroke_ L2 - http://dx.doi.org/10.1038/s41419-019-1798-4 DB - PRIME DP - Unbound Medicine ER -