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Autophagy in Rat Müller Glial Cells Is Modulated by the Sirtuin 4/AMPK/mTOR Pathway and Induces Apoptosis under Oxidative Stress

Müller glial cells (MGCs) are a group of glial cells in the retina that provide essential support to retinal neurons; however, the understanding of MGC apoptosis and autophagy remains limited. This study was aimed at investigating the role of autophagy in MGCs under normal and oxidative conditions,...

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Autores principales: Qin, Mengqi, Xie, Zhi, Cao, Ting, Wang, Zhiruo, Zhang, Xiaoyu, Wang, Feifei, Wei, Wei, Jin, Ming, Ma, Jingyuan, Zeng, Ling, Wang, Yanan, Pei, Shaonan, Zhang, Xu
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9454555/
https://www.ncbi.nlm.nih.gov/pubmed/36078054
http://dx.doi.org/10.3390/cells11172645
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author Qin, Mengqi
Xie, Zhi
Cao, Ting
Wang, Zhiruo
Zhang, Xiaoyu
Wang, Feifei
Wei, Wei
Jin, Ming
Ma, Jingyuan
Zeng, Ling
Wang, Yanan
Pei, Shaonan
Zhang, Xu
author_facet Qin, Mengqi
Xie, Zhi
Cao, Ting
Wang, Zhiruo
Zhang, Xiaoyu
Wang, Feifei
Wei, Wei
Jin, Ming
Ma, Jingyuan
Zeng, Ling
Wang, Yanan
Pei, Shaonan
Zhang, Xu
author_sort Qin, Mengqi
collection PubMed
description Müller glial cells (MGCs) are a group of glial cells in the retina that provide essential support to retinal neurons; however, the understanding of MGC apoptosis and autophagy remains limited. This study was aimed at investigating the role of autophagy in MGCs under normal and oxidative conditions, and identifying the underlying mechanisms. In addition, the sirtuin 4 (SIRT4)-mediated signaling pathway was observed to regulate the autophagic process in MGCs. To assess the effect of autophagy on MGC mitochondrial function and survival, we treated rMC-1 cells—rat-derived Müller glial cells—with rapamycin and 3-methyladenine (3-MA), and found that MGC death was not induced by such treatment, while autophagic dysfunction could increase MGC apoptosis under oxidative stress, as reflected by the expression level of cleaved caspase 3 and PI staining. In addition, the downregulation of autophagy by 3-MA could influence the morphology of the mitochondrial network structure, the mitochondrial membrane potential, and generation of reactive oxygen species (ROS) under oxidative stress. Moreover, SIRT4 depletion enhanced autophagosome formation, as verified by an increase in the LC3 II/I ratio and a decrease in the expression of SQSTM1/p62, and vice versa. The inhibition of AMPK phosphorylation by compound C could reverse these changes in LC3 II/I and SQSTM1/p62 caused by SIRT4 knockdown. Our research concludes that MGCs can endure autophagic dysfunction in the absence of oxidative stress, while the downregulation of autophagy can cause MGCs to become more sensitized to oxidative stress. Simultaneous exposure to oxidative stress and autophagic dysfunction in MGCs can result in a pronounced impairment of cell survival. Mechanically, SIRT4 depletion can activate the autophagic process in MGCs by regulating the AMPK–mTOR signaling pathway.
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spelling pubmed-94545552022-09-09 Autophagy in Rat Müller Glial Cells Is Modulated by the Sirtuin 4/AMPK/mTOR Pathway and Induces Apoptosis under Oxidative Stress Qin, Mengqi Xie, Zhi Cao, Ting Wang, Zhiruo Zhang, Xiaoyu Wang, Feifei Wei, Wei Jin, Ming Ma, Jingyuan Zeng, Ling Wang, Yanan Pei, Shaonan Zhang, Xu Cells Article Müller glial cells (MGCs) are a group of glial cells in the retina that provide essential support to retinal neurons; however, the understanding of MGC apoptosis and autophagy remains limited. This study was aimed at investigating the role of autophagy in MGCs under normal and oxidative conditions, and identifying the underlying mechanisms. In addition, the sirtuin 4 (SIRT4)-mediated signaling pathway was observed to regulate the autophagic process in MGCs. To assess the effect of autophagy on MGC mitochondrial function and survival, we treated rMC-1 cells—rat-derived Müller glial cells—with rapamycin and 3-methyladenine (3-MA), and found that MGC death was not induced by such treatment, while autophagic dysfunction could increase MGC apoptosis under oxidative stress, as reflected by the expression level of cleaved caspase 3 and PI staining. In addition, the downregulation of autophagy by 3-MA could influence the morphology of the mitochondrial network structure, the mitochondrial membrane potential, and generation of reactive oxygen species (ROS) under oxidative stress. Moreover, SIRT4 depletion enhanced autophagosome formation, as verified by an increase in the LC3 II/I ratio and a decrease in the expression of SQSTM1/p62, and vice versa. The inhibition of AMPK phosphorylation by compound C could reverse these changes in LC3 II/I and SQSTM1/p62 caused by SIRT4 knockdown. Our research concludes that MGCs can endure autophagic dysfunction in the absence of oxidative stress, while the downregulation of autophagy can cause MGCs to become more sensitized to oxidative stress. Simultaneous exposure to oxidative stress and autophagic dysfunction in MGCs can result in a pronounced impairment of cell survival. Mechanically, SIRT4 depletion can activate the autophagic process in MGCs by regulating the AMPK–mTOR signaling pathway. MDPI 2022-08-25 /pmc/articles/PMC9454555/ /pubmed/36078054 http://dx.doi.org/10.3390/cells11172645 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Qin, Mengqi
Xie, Zhi
Cao, Ting
Wang, Zhiruo
Zhang, Xiaoyu
Wang, Feifei
Wei, Wei
Jin, Ming
Ma, Jingyuan
Zeng, Ling
Wang, Yanan
Pei, Shaonan
Zhang, Xu
Autophagy in Rat Müller Glial Cells Is Modulated by the Sirtuin 4/AMPK/mTOR Pathway and Induces Apoptosis under Oxidative Stress
title Autophagy in Rat Müller Glial Cells Is Modulated by the Sirtuin 4/AMPK/mTOR Pathway and Induces Apoptosis under Oxidative Stress
title_full Autophagy in Rat Müller Glial Cells Is Modulated by the Sirtuin 4/AMPK/mTOR Pathway and Induces Apoptosis under Oxidative Stress
title_fullStr Autophagy in Rat Müller Glial Cells Is Modulated by the Sirtuin 4/AMPK/mTOR Pathway and Induces Apoptosis under Oxidative Stress
title_full_unstemmed Autophagy in Rat Müller Glial Cells Is Modulated by the Sirtuin 4/AMPK/mTOR Pathway and Induces Apoptosis under Oxidative Stress
title_short Autophagy in Rat Müller Glial Cells Is Modulated by the Sirtuin 4/AMPK/mTOR Pathway and Induces Apoptosis under Oxidative Stress
title_sort autophagy in rat müller glial cells is modulated by the sirtuin 4/ampk/mtor pathway and induces apoptosis under oxidative stress
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9454555/
https://www.ncbi.nlm.nih.gov/pubmed/36078054
http://dx.doi.org/10.3390/cells11172645
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