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Kuramoto K, Liang H, Hong JH, He C. Exercise-activated hepatic autophagy via the FN1-α5β1 integrin pathway drives metabolic benefits of exercise. Cell Metab 2023; 35:620-632.e5. [PMID: 36812915 PMCID: PMC10079584 DOI: 10.1016/j.cmet.2023.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 12/01/2022] [Accepted: 01/26/2023] [Indexed: 02/24/2023]
Abstract
How exercise elicits systemic metabolic benefits in both muscles and non-contractile tissues is unclear. Autophagy is a stress-induced lysosomal degradation pathway that mediates protein and organelle turnover and metabolic adaptation. Exercise activates autophagy in not only contracting muscles but also non-contractile tissues including the liver. However, the role and mechanism of exercise-activated autophagy in non-contractile tissues remain mysterious. Here, we show that hepatic autophagy activation is essential for exercise-induced metabolic benefits. Plasma or serum from exercised mice is sufficient to activate autophagy in cells. By proteomic studies, we identify fibronectin (FN1), which was previously considered as an extracellular matrix protein, as an exercise-induced, muscle-secreted, autophagy-inducing circulating factor. Muscle-secreted FN1 mediates exercise-induced hepatic autophagy and systemic insulin sensitization via the hepatic receptor α5β1 integrin and the downstream IKKα/β-JNK1-BECN1 pathway. Thus, we demonstrate that hepatic autophagy activation drives exercise-induced metabolic benefits against diabetes via muscle-secreted soluble FN1 and hepatic α5β1 integrin signaling.
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Affiliation(s)
- Kenta Kuramoto
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Huijia Liang
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Jung-Hwa Hong
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Congcong He
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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Notch1 Is Involved in Physiologic Cardiac Hypertrophy of Mice via the p38 Signaling Pathway after Voluntary Running. Int J Mol Sci 2023; 24:ijms24043212. [PMID: 36834623 PMCID: PMC9966550 DOI: 10.3390/ijms24043212] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/26/2023] [Accepted: 02/01/2023] [Indexed: 02/10/2023] Open
Abstract
Appropriate exercise such as voluntary wheel-running can induce physiological cardiac hypertrophy. Notch1 plays an important role in cardiac hypertrophy; however, the experimental results are inconsistent. In this experiment, we aimed to explore the role of Notch1 in physiological cardiac hypertrophy. Twenty-nine adult male mice were randomly divided into a Notch1 heterozygous deficient control (Notch1+/- CON) group, a Notch1 heterozygous deficient running (Notch1+/- RUN) group, a wild type control (WT CON) group, and a wild type running (WT RUN) group. Mice in the Notch1+/- RUN and WT RUN groups had access to voluntary wheel-running for two weeks. Next, the cardiac function of all of the mice was examined by echocardiography. The H&E staining, Masson trichrome staining, and a Western blot assay were carried out to analyze cardiac hypertrophy, cardiac fibrosis, and the expression of proteins relating to cardiac hypertrophy. After two-weeks of running, the Notch1 receptor expression was decreased in the hearts of the WT RUN group. The degree of cardiac hypertrophy in the Notch1+/- RUN mice was lower than that of their littermate control. Compared to the Notch1+/- CON group, Notch1 heterozygous deficiency could lead to a decrease in Beclin-1 expression and the ratio of LC3II/LC3I in the Notch1+/- RUN group. The results suggest that Notch1 heterozygous deficiency could partly dampen the induction of autophagy. Moreover, Notch1 deficiency may lead to the inactivation of p38 and the reduction of β-catenin expression in the Notch1+/- RUN group. In conclusion, Notch1 plays a critical role in physiologic cardiac hypertrophy through the p38 signaling pathway. Our results will help to understand the underlying mechanism of Notch1 on physiological cardiac hypertrophy.
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Park K, Lee MS. Current Status of Autophagy Enhancers in Metabolic Disorders and Other Diseases. Front Cell Dev Biol 2022; 10:811701. [PMID: 35237600 PMCID: PMC8882819 DOI: 10.3389/fcell.2022.811701] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/13/2022] [Indexed: 12/21/2022] Open
Abstract
Autophagy is pivotal in the maintenance of organelle function and intracellular nutrient balance. Besides the role of autophagy in the homeostasis and physiology of the individual tissues and whole organism in vivo, dysregulated autophagy has been incriminated in the pathogenesis of a variety of diseases including metabolic diseases, neurodegenerative diseases, cardiovascular diseases, inflammatory or immunological disorders, cancer and aging. Search for autophagy modulators has been widely conducted to amend dysregulation of autophagy or pharmacologically modulate autophagy in those diseases. Current data support the view that autophagy modulation could be a new modality for treatment of metabolic syndrome associated with lipid overload, human-type diabetes characterized by deposition of islet amyloid or other diseases including neurodegenerative diseases, infection and cardiovascular diseases. While clinically available bona fide autophagy modulators have not been developed yet, it is expected that on-going investigation will lead to the development of authentic autophagy modulators that can be safely administered to patients in the near future and will open a new horizon for treatment of incurable or difficult diseases.
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Abstract
Obesity is a growing human health concern worldwide and imposes adverse effects on many cell types and organ systems, including the kidneys. Obesity interferes with various cellular processes by increasing lipid accumulation and oxidation, insulin resistance, and inflammation. Autophagy is an important cellular process to maintain hemostasis and preserve resources, but might be altered in obesity. Interestingly, experimental studies have shown either an increase or a decrease in the rate of autophagy, and accumulation of byproducts and mediators of this cascade in kidneys of obese individuals. Hence, whether autophagy is beneficial or detrimental under these conditions remains unresolved. This review summarizes emerging evidence linking superfluous fat accumulation to alterations in autophagy. Elucidating the role of autophagy in the pathogenesis and complications of obesity in the kidney might help in the identification of therapeutic targets to prevent or delay the development of chronic kidney disease in obese subjects. Autophagy, kidney, obesity, lipids.
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Affiliation(s)
- Ramyar Ghandriz
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN
| | - Lilach O Lerman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN.
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Zhang Q, Presswalla F, Ali RR, Zacks DN, Thompson DA, Miller JML. Pharmacologic activation of autophagy without direct mTOR inhibition as a therapeutic strategy for treating dry macular degeneration. Aging (Albany NY) 2021; 13:10866-10890. [PMID: 33872219 PMCID: PMC8109132 DOI: 10.18632/aging.202974] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 03/13/2021] [Indexed: 12/15/2022]
Abstract
Dry age-related macular degeneration (AMD) is marked by the accumulation of extracellular and intracellular lipid-rich deposits within and around the retinal pigment epithelium (RPE). Inducing autophagy, a conserved, intracellular degradative pathway, is a potential treatment strategy to prevent disease by clearing these deposits. However, mTOR inhibition, the major mechanism for inducing autophagy, disrupts core RPE functions. Here, we screened autophagy inducers that do not directly inhibit mTOR for their potential as an AMD therapeutic in primary human RPE culture. Only two out of more than thirty autophagy inducers tested reliably increased autophagy flux in RPE, emphasizing that autophagy induction mechanistically differs across distinct tissues. In contrast to mTOR inhibitors, these compounds preserved RPE health, and one inducer, the FDA-approved compound flubendazole (FLBZ), reduced the secretion of apolipoprotein that contributes to extracellular deposits termed drusen. Simultaneously, FLBZ increased production of the lipid-degradation product β-hydroxybutyrate, which is used by photoreceptor cells as an energy source. FLBZ also reduced the accumulation of intracellular deposits, termed lipofuscin, and alleviated lipofuscin-induced cellular senescence and tight-junction disruption. FLBZ triggered compaction of lipofuscin-like granules into a potentially less toxic form. Thus, induction of RPE autophagy without direct mTOR inhibition is a promising therapeutic approach for dry AMD.
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Affiliation(s)
- Qitao Zhang
- Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Feriel Presswalla
- Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Robin R. Ali
- Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
- KCL Centre for Cell and Gene Therapy, London, England WC2R 2LS, United Kingdom
| | - David N. Zacks
- Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Debra A. Thompson
- Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48105, USA
| | - Jason ML. Miller
- Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
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Kim YJ, Kong Q, Yamamoto S, Kuramoto K, Huang M, Wang N, Hong JH, Xiao T, Levine B, Qiu X, Zhao Y, Miller RJ, Dong H, Meltzer HY, Xu M, He C. An autophagy-related protein Becn2 regulates cocaine reward behaviors in the dopaminergic system. SCIENCE ADVANCES 2021; 7:7/8/eabc8310. [PMID: 33608268 PMCID: PMC7895433 DOI: 10.1126/sciadv.abc8310] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 01/06/2021] [Indexed: 06/12/2023]
Abstract
Drug abuse is a foremost public health problem. Cocaine is a widely abused drug worldwide that produces various reward-related behaviors. The mechanisms that underlie cocaine-induced disorders are unresolved, and effective treatments are lacking. Here, we found that an autophagy-related protein Becn2 is a previously unidentified regulator of cocaine reward behaviors. Becn2 deletion protects mice from cocaine-stimulated locomotion and reward behaviors, as well as cocaine-induced dopamine accumulation and signaling, by increasing presynaptic dopamine receptor 2 (D2R) autoreceptors in dopamine neurons. Becn2 regulates D2R endolysosomal trafficking, degradation, and cocaine-induced behaviors via interacting with a D2R-bound adaptor GASP1. Inactivating Becn2 by upstream autophagy inhibitors stabilizes striatal presynaptic D2R, reduces dopamine release and signaling, and prevents cocaine reward in normal mice. Thus, the autophagy protein Becn2 is essential for cocaine psychomotor stimulation and reward through regulating dopamine neurotransmission, and targeting Becn2 by autophagy inhibitors is a potential strategy to prevent cocaine-induced behaviors.
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Affiliation(s)
- Yoon-Jin Kim
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Qingyao Kong
- Department of Anesthesia and Critical Care, The University of Chicago, Chicago, IL 60637, USA
| | - Soh Yamamoto
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Kenta Kuramoto
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Mei Huang
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Nan Wang
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Key Laboratory of Industrial Microbiology, Ministry of Education and Tianjin City, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Jung Hwa Hong
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Tong Xiao
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Beth Levine
- Departments of Internal Medicine and Microbiology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xianxiu Qiu
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Yanxiang Zhao
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Richard J Miller
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Hongxin Dong
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Herbert Y Meltzer
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Ming Xu
- Department of Anesthesia and Critical Care, The University of Chicago, Chicago, IL 60637, USA
| | - Congcong He
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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Chindemi C, Cirielli V, Cima L, Danzi O, Raniero D, Tagliaro F, Turrina S, Eccher A, Ghimenton C, Bortolotti F, Brunelli M, De Leo D. Autophagy pathways in drug abusers after forensic autopsy: LC3B, ph-mTOR and p70S6K analysis. MEDICINE, SCIENCE, AND THE LAW 2019; 59:49-56. [PMID: 30852985 DOI: 10.1177/0025802419828910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
INTRODUCTION Autophagy plays a role in various central nervous system diseases. Little is known about its molecular activation in drug addiction. Our aim was to investigate the signalling pathways of autophagy in brain tissues from drug abusers. METHODS Twenty-five drug abusers with acute lethal intoxication and 10 controls were medico-legally autopsied. Brain-tissue samples from the parietal cortex and cerebellum were obtained. Expression of LC3B, phospho-mTOR (ph-mTOR) and phospho70S6 Kinase (p70S6K) was identified in tissue microarrays, with three tissue spots per case. Blood, urine or vitreous humour were tested in all cases to identify the acute intoxication. Hair analysis was performed in 14 cases to confirm chronic intoxication; the remaining cases had a documented medical history of chronic abuse. RESULTS The autophagy marker LC3B was always positive on both the cortex and the cerebellum, stratified as strongly in 18 (72%) cases and weakly positive in seven (28%) cases. ph-mTOR was negative in all cases. The p70S6K molecule showed positivity in 14 (56%) cases on cortex tissue. The cerebellum was always negative, except for Purkinje cells. Drug abusers had statistically more double positive cases (LC3B-p70S6K) than controls ( p=0.0094). CONCLUSION Autophagy pathways were activated in our series, and 56% of drug abusers showed simultaneous LC3B-p70S6K immunoexpression on tissue from the parietal cortex and cerebellum. This may be of value in autopsy practice as an indicator of brain damage due to drug abuse and could serve as alternative or additional double sensitive diagnostic method to detect drug-related deaths using a tissue-based rationale.
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Affiliation(s)
- Chiara Chindemi
- 1 Department of Diagnostics and Public Health, Legal Medicine and Forensic Pathology Unit, University and Hospital Trust of Verona, Italy
| | - Vito Cirielli
- 1 Department of Diagnostics and Public Health, Legal Medicine and Forensic Pathology Unit, University and Hospital Trust of Verona, Italy
| | - Luca Cima
- 2 Department of Diagnostics and Public Health, Pathology Unit, University and Hospital Trust of Verona, Italy
| | - Olivia Danzi
- 3 Department of Neurological, Biomedical and Movement Sciences, University and Hospital Trust of Verona, Italy
| | - Dario Raniero
- 1 Department of Diagnostics and Public Health, Legal Medicine and Forensic Pathology Unit, University and Hospital Trust of Verona, Italy
| | - Franco Tagliaro
- 1 Department of Diagnostics and Public Health, Legal Medicine and Forensic Pathology Unit, University and Hospital Trust of Verona, Italy
- 4 Institute of Pharmacy and Translational Medicine, Sechenov First Moscow State Medical University, Russia
| | - Stefania Turrina
- 1 Department of Diagnostics and Public Health, Legal Medicine and Forensic Pathology Unit, University and Hospital Trust of Verona, Italy
| | - Albino Eccher
- 2 Department of Diagnostics and Public Health, Pathology Unit, University and Hospital Trust of Verona, Italy
| | - Claudio Ghimenton
- 2 Department of Diagnostics and Public Health, Pathology Unit, University and Hospital Trust of Verona, Italy
| | - Federica Bortolotti
- 1 Department of Diagnostics and Public Health, Legal Medicine and Forensic Pathology Unit, University and Hospital Trust of Verona, Italy
| | - Matteo Brunelli
- 1 Department of Diagnostics and Public Health, Legal Medicine and Forensic Pathology Unit, University and Hospital Trust of Verona, Italy
| | - Domenico De Leo
- 1 Department of Diagnostics and Public Health, Legal Medicine and Forensic Pathology Unit, University and Hospital Trust of Verona, Italy
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Rocchi A, Yamamoto S, Ting T, Fan Y, Sadleir K, Wang Y, Zhang W, Huang S, Levine B, Vassar R, He C. A Becn1 mutation mediates hyperactive autophagic sequestration of amyloid oligomers and improved cognition in Alzheimer's disease. PLoS Genet 2017; 13:e1006962. [PMID: 28806762 PMCID: PMC5570506 DOI: 10.1371/journal.pgen.1006962] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 08/24/2017] [Accepted: 08/07/2017] [Indexed: 12/31/2022] Open
Abstract
Impairment of the autophagy pathway has been observed during the pathogenesis of Alzheimer's disease (AD), a neurodegenerative disorder characterized by abnormal deposition of extracellular and intracellular amyloid β (Aβ) peptides. Yet the role of autophagy in Aβ production and AD progression is complex. To study whether increased basal autophagy plays a beneficial role in Aβ clearance and cognitive improvement, we developed a novel genetic model to hyperactivate autophagy in vivo. We found that knock-in of a point mutation F121A in the essential autophagy gene Beclin 1/Becn1 in mice significantly reduces the interaction of BECN1 with its inhibitor BCL2, and thus leads to constitutively active autophagy even under non-autophagy-inducing conditions in multiple tissues, including brain. Becn1F121A-mediated autophagy hyperactivation significantly decreases amyloid accumulation, prevents cognitive decline, and restores survival in AD mouse models. Using an immunoisolation method, we found biochemically that Aβ oligomers are autophagic substrates and sequestered inside autophagosomes in the brain of autophagy-hyperactive AD mice. In addition to genetic activation of autophagy by Becn1 gain-of-function, we also found that ML246, a small-molecule autophagy inducer, as well as voluntary exercise, a physiological autophagy inducer, exert similar Becn1-dependent protective effects on Aβ removal and memory in AD mice. Taken together, these results demonstrate that genetically disrupting BECN1-BCL2 binding hyperactivates autophagy in vivo, which sequestrates amyloid oligomers and prevents AD progression. The study establishes new approaches to activate autophagy in the brain, and reveals the important function of Becn1-mediated autophagy hyperactivation in the prevention of AD.
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Affiliation(s)
- Altea Rocchi
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Soh Yamamoto
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
- Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Tabitha Ting
- Center for Autophagy Research, Department of Internal Medicine, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Yuying Fan
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
- Key Laboratory on Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun, Jilin, China
| | - Katherine Sadleir
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Yigang Wang
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
- School of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China
| | - Weiran Zhang
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Sui Huang
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Beth Levine
- Center for Autophagy Research, Department of Internal Medicine, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Robert Vassar
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Congcong He
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
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Rocchi A, He C. Regulation of Exercise-Induced Autophagy in Skeletal Muscle. CURRENT PATHOBIOLOGY REPORTS 2017; 5:177-186. [PMID: 29057166 PMCID: PMC5646231 DOI: 10.1007/s40139-017-0135-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
PURPOSE OF REVIEW Physical exercise is a highly effective method to prevent several pathogenic conditions, such as obesity, type 2 diabetes and cardiovascular diseases, largely due to metabolic adaptations induced by exercise in skeletal muscle. Yet how exercise induces the beneficial effects in muscle remains to be fully elucidated. Autophagy is a lysosomal degradation pathway that regulates nutrient recycling, energy production and organelle quality control. The autophagy pathway is upregulated in response to stress during exercise and muscle contraction, and may be an important mechanism mediating exercise-induced health benefits. RECENT FINDINGS A number of studies have indicated that physical exercise induces non-selective autophagy and selective mitophagy in skeletal muscle in animal models and humans. The AMPK-ULK1 and the FoxO3 signaling pathways play an essential role in the activation of the upstream autophagy machinery in skeletal muscle during exercise. The autophagy activity is required for health benefits of exercise, as in different autophagy-deficient mouse lines exercise-induced effects are abolished. SUMMARY This review aims to summarize and highlight the most recent findings on the role of autophagy in muscle maintenance, the molecular pathways that upregulate autophagy during exercise, and the potential functions of exercise-induced autophagy and mitophagy in skeletal muscle.
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Affiliation(s)
- Altea Rocchi
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Congcong He
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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Abstract
Autophagy is a lysosomal degradation pathway essential for cell homeostasis, function and differentiation. Under stress conditions, autophagy is induced and targets various cargos, such as bulk cytosol, damaged organelles and misfolded proteins, for degradation in lysosomes. Resulting nutrient molecules are recycled back to the cytosol for new protein synthesis and ATP production. Upregulation of autophagy has beneficial effects against the pathogenesis of many diseases, and pharmacological and physiological strategies to activate autophagy have been reported. Aerobic exercise is recently identified as an efficient autophagy inducer in multiple organs in mice, including muscle, liver, heart and brain. Here we show procedures to induce autophagy in vivo by either forced treadmill exercise or voluntary wheel running. We also demonstrate microscopic and biochemical methods to quantitatively analyze autophagy levels in mouse tissues, using the marker proteins LC3 and p62 that are transported to and degraded in lysosomes along with autophagosomes.
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Affiliation(s)
- Altea Rocchi
- Department of Cell and Molecular Biology, Northwestern University
| | - Congcong He
- Department of Cell and Molecular Biology, Northwestern University;
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