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Corasaniti MT, Bagetta G, Nicotera P, Maione S, Tonin P, Guida F, Scuteri D. Exploitation of Autophagy Inducers in the Management of Dementia: A Systematic Review. Int J Mol Sci 2024; 25:1264. [PMID: 38279266 PMCID: PMC10816917 DOI: 10.3390/ijms25021264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 01/13/2024] [Accepted: 01/16/2024] [Indexed: 01/28/2024] Open
Abstract
The social burden of dementia is remarkable since it affects some 57.4 million people all over the world. Impairment of autophagy in age-related diseases, such as dementia, deserves deep investigation for the detection of novel disease-modifying approaches. Several drugs belonging to different classes were suggested to be effective in managing Alzheimer's disease (AD) by means of autophagy induction. Useful autophagy inducers in AD should be endowed with a direct, measurable effect on autophagy, have a safe tolerability profile, and have the capability to cross the blood-brain barrier, at least with poor penetration. According to the PRISMA 2020 recommendations, we propose here a systematic review to appraise the measurable effectiveness of autophagy inducers in the improvement of cognitive decline and neuropsychiatric symptoms in clinical trials and retrospective studies. The systematic search retrieved 3067 records, 10 of which met the eligibility criteria. The outcomes most influenced by the treatment were cognition and executive functioning, pointing at a role for metformin, resveratrol, masitinib and TPI-287, with an overall tolerable safety profile. Differences in sample power, intervention, patients enrolled, assessment, and measure of outcomes prevents generalization of results. Moreover, the domain of behavioral symptoms was found to be less investigated, thus prompting new prospective studies with homogeneous design. PROSPERO registration: CRD42023393456.
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Affiliation(s)
| | - Giacinto Bagetta
- Pharmacotechnology Documentation and Transfer Unit, Preclinical and Translational Pharmacology, Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende, Italy;
| | - Pierluigi Nicotera
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany;
| | - Sabatino Maione
- Division of Pharmacology, Department of Experimental Medicine, University of Campania “L. Vanvitelli”, 80138 Naples, Italy; (S.M.); (F.G.)
- Laboratory of Biomolecules, Venoms and Theranostic Application, Institute Pasteur de Tunis, Université Tunis El Manar, Tunis 1002, Tunisia
| | - Paolo Tonin
- Regional Center for Serious Brain Injuries, S. Anna Institute, 88900 Crotone, Italy;
| | - Francesca Guida
- Division of Pharmacology, Department of Experimental Medicine, University of Campania “L. Vanvitelli”, 80138 Naples, Italy; (S.M.); (F.G.)
| | - Damiana Scuteri
- Department of Health Sciences, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy;
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Choi H, Kim IS, Mun JY. Propionic acid induces dendritic spine loss by MAPK/ERK signaling and dysregulation of autophagic flux. Mol Brain 2020; 13:86. [PMID: 32487196 PMCID: PMC7268420 DOI: 10.1186/s13041-020-00626-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 05/26/2020] [Indexed: 02/06/2023] Open
Abstract
Propionic acid (PPA) is a short-chain fatty acid that is an important mediator of cellular metabolism. It is also a by-product of human gut enterobacteria and a common food preservative. A recent study found that rats administered with PPA showed autistic-like behaviors like restricted interest, impaired social behavior, and impaired reversal in a T-maze task. This study aimed to identify a link between PPA and autism phenotypes facilitated by signaling mechanisms in hippocampal neurons. Findings indicated autism-like pathogenesis associated with reduced dendritic spines in PPA-treated hippocampal neurons. To uncover the mechanisms underlying this loss, we evaluated autophagic flux, a functional readout of autophagy, using relevant biomedical markers. Results indicated that autophagic flux is impaired in PPA-treated hippocampal neurons. At a molecular level, the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway was activated and autophagic activity was impaired. We also observed that a MAPK inhibitor rescued dendritic spine loss in PPA-treated hippocampal neurons. Taken together, these results suggest a previously unknown link between PPA and autophagy in spine formation regulation in hippocampal neurons via MAPK/ERK signaling. Our results indicate that MAPK/ERK signaling participates in autism pathogenesis by autophagy disruption affecting dendritic spine density. This study may help to elucidate other mechanisms underlying autism and provide a potential strategy for treating ASD-associated pathology.
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Affiliation(s)
- Hyosun Choi
- BK21 Plus Program, Department of Senior Healthcare, Graduate School, Eulji University, Daejeon, South Korea.,Neural Circuit Research Group, Korea Brain Research Institute, Daegu, 41068, Republic of Korea
| | - In Sik Kim
- BK21 Plus Program, Department of Senior Healthcare, Graduate School, Eulji University, Daejeon, South Korea.,Department of Biomedical Laboratory Science, Eulji University School of Medicine, Daejeon, South Korea
| | - Ji Young Mun
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu, 41068, Republic of Korea.
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Tao XL, Zhao W, Tong W, Wang XF, Dou LL, Chen JM, Liu N, Lu Y, Zhang YB, Jin XP, Shen YF, Zhao HY, Jin H, Li YG. The effects of autophagy on the replication of Nelson Bay orthoreovirus. Virol J 2019; 16:90. [PMID: 31319897 PMCID: PMC6639940 DOI: 10.1186/s12985-019-1196-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 06/26/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Nelson Bay orthoreovirus (NBV) was first isolated over 40 years ago from a fruit bat in Australia. Normally, NBV does not cause human diseases, but recently several NBV strains have been associated with human respiratory tract infections, thus attracting clinical attention. Autophagy, an evolutionarily conserved process in eukaryotic cells, degrades intracellular substrates, participates in multiple physiological processes, and maintains cellular homeostasis. In addition, autophagy is intimately involved in viral infection. METHODS A new strain of NBV, isolated from a patient with a respiratory tract infection who returned to Japan from Bali, Indonesia, in 2007, was used in this study. NBV was rescued using a reverse genetics system involving cotransfection of BHK cells with 11 plasmids (pT7-L1 MB, pT7-L2 MB, pT7-L3 MB, pT7-M1 MB, pT7-M2 MB, pT7-M3 MB, pT7-S1 MB, pT7-S2 MB, pT7-S3 MB, pT7-S4 MB, and pcDNA3.1-T7), yielding NBV-MB. Recovered viruses were confirmed by immunofluorescence. The effect of NBV-MB on autophagy was evaluated by measuring the LC3-I/II proteins by immunoblot analysis after infection of BHK cells. Furthermore, after treatment with rapamycin (RAPA), 3-methyladenine (3-MA), chloroquine (CQ), or plasmid (GFP-LC3) transfection, the changes in expression of the LC3 gene and the amount of LC3-I/II protein were examined. In addition, variations in viral titer were assayed after treatment of BHK cells with drugs or after transfection with plasmids pCAGM3 and pCAGS3, which encode virus nonstructural proteins μNS and σNS, respectively. RESULTS NBV-MB infection induced autophagy in host cells; however, the level of induction was dependent on viral replication. Induction of autophagy increased viral replication. By contrast, inhibiting autophagy suppressed NBV replication, albeit not significantly. The NBV-MB nonstructural protein μNS was involved in the induction of autophagy with viral infection. CONCLUSIONS NBV-MB infection triggered autophagy. Also, the NBV nonstructural protein μNS may contribute to augmentation of autophagy upon viral infection.
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Affiliation(s)
- Xiao-Li Tao
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, China Medical University, No. 77, Puhe Road, Shenyang North New Area, Shenyang City, 110013, Liaoning Province, People's Republic of China.,Department of Pathogenic Microbiology, College of Basic Medical Sciences, Jinzhou Medical University, No. 40, the Third Section of SongPo Rd, Jinzhou City, 121200, Liaoning Province, China
| | - Wei Zhao
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, Jinzhou Medical University, No. 40, the Third Section of SongPo Rd, Jinzhou City, 121200, Liaoning Province, China
| | - Wei Tong
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, Jinzhou Medical University, No. 40, the Third Section of SongPo Rd, Jinzhou City, 121200, Liaoning Province, China
| | - Xiao-Fang Wang
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, Jinzhou Medical University, No. 40, the Third Section of SongPo Rd, Jinzhou City, 121200, Liaoning Province, China
| | - Li-Li Dou
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, Jinzhou Medical University, No. 40, the Third Section of SongPo Rd, Jinzhou City, 121200, Liaoning Province, China
| | - Jiang-Man Chen
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, Jinzhou Medical University, No. 40, the Third Section of SongPo Rd, Jinzhou City, 121200, Liaoning Province, China
| | - Nian Liu
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, Jinzhou Medical University, No. 40, the Third Section of SongPo Rd, Jinzhou City, 121200, Liaoning Province, China
| | - Ying Lu
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, Jinzhou Medical University, No. 40, the Third Section of SongPo Rd, Jinzhou City, 121200, Liaoning Province, China
| | - Yi-Bo Zhang
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, Jinzhou Medical University, No. 40, the Third Section of SongPo Rd, Jinzhou City, 121200, Liaoning Province, China
| | - Xu-Peng Jin
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, Jinzhou Medical University, No. 40, the Third Section of SongPo Rd, Jinzhou City, 121200, Liaoning Province, China
| | - Yan-Fei Shen
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, Jinzhou Medical University, No. 40, the Third Section of SongPo Rd, Jinzhou City, 121200, Liaoning Province, China
| | - Hong-Yan Zhao
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, Jinzhou Medical University, No. 40, the Third Section of SongPo Rd, Jinzhou City, 121200, Liaoning Province, China
| | - Hong Jin
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, China Medical University, No. 77, Puhe Road, Shenyang North New Area, Shenyang City, 110013, Liaoning Province, People's Republic of China.
| | - Yong-Gang Li
- Department of Pathogenic Microbiology, College of Basic Medical Sciences, Jinzhou Medical University, No. 40, the Third Section of SongPo Rd, Jinzhou City, 121200, Liaoning Province, China.
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Chen P, Geng N, Zhou D, Zhu Y, Xu Y, Liu K, Liu Y, Liu J. The regulatory role of COX-2 in the interaction between Cr(VI)-induced endoplasmic reticulum stress and autophagy in DF-1 cells. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 170:112-119. [PMID: 30529609 DOI: 10.1016/j.ecoenv.2018.11.120] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 10/31/2018] [Accepted: 11/27/2018] [Indexed: 06/09/2023]
Abstract
Hexavalent chromium (Cr(VI)) is a common environmental pollutant. Exposure of Cr(VI) can lead to cell autophagy, but the preventive measures for diminishing Cr(VI)-induced autophagy need further study. COX-2 can be induced by several heavy metals and can lead to endoplasmic reticulum (ER) stress and autophagy; thus, COX-2, ER stress, and autophagy may be related. This study mainly investigated the role of COX-2 in the eIF2α-ATF4 pathway, which is a major pathway in cell autophagy. In this study, Cr(VI) was used as a xenobiotic to determine changes in the parameters of ER stress, autophagy, and COX-2 levels. At the same time, a clear contrast was obtained by assigning positive and negative controls of ER stress and autophagy. The results showed that during Cr(VI) invasion, the parameters of ER stress and autophagy (such as BiP, PERK, p62, LC3-II, and mTOR) were enhanced, similarly to the positive control of ER stress and/or the autophagy controls. Such enhancement is a protective mechanism for cell survival. Additionally, the COX-2 levels increased. Moreover, when COX-2 was inhibited, the PERK level remained high, whereas the LC3-II level decreased. This finding suggests that COX-2 specifically affects the interaction between ER stress and autophagy. Notably, this study reveals that Cr(VI) can induce ER stress and autophagy in DF-1 cells and that COX-2 plays an essential role in the interaction between ER stress and autophagy.
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Affiliation(s)
- Peng Chen
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an 271018, PR China; Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Street, Taian City, Shandong Province 271018, PR China
| | - Na Geng
- Research Center for Animal Disease Control Engineering Shandong Province, Shandong Agricultural University, Tai'an 271018, PR China
| | - Dong Zhou
- College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling 712100, PR China
| | - Yiran Zhu
- Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Street, Taian City, Shandong Province 271018, PR China
| | - Yuliang Xu
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an 271018, PR China
| | - Kangping Liu
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an 271018, PR China
| | - Yongxia Liu
- Research Center for Animal Disease Control Engineering Shandong Province, Shandong Agricultural University, Tai'an 271018, PR China.
| | - Jianzhu Liu
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an 271018, PR China.
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5
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Glycophagy: An emerging target in pathology. Clin Chim Acta 2018; 484:298-303. [DOI: 10.1016/j.cca.2018.06.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/08/2018] [Accepted: 06/08/2018] [Indexed: 12/14/2022]
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6
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Hanson PK. Saccharomyces cerevisiae: A Unicellular Model Genetic Organism of Enduring Importance. ACTA ACUST UNITED AC 2018. [DOI: 10.1002/cpet.21] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Pamela K. Hanson
- Department of Biology, Birmingham-Southern College; Birmingham Alabama
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7
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Przybylska-Gornowicz B, Lewczuk B, Ziółkowska N, Prusik M. Adrenergic regulation of cytoplasmic structures related to secretory processes in pig pinealocytes-an ultrastructural, quantitative study. Micron 2017. [PMID: 28622599 DOI: 10.1016/j.micron.2017.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Two structures, considered as secretory in nature, are present in the pinealocytes in of the domestic pig show the presence of two structures, which are considered as secretory in nature - the dense core vesicles (DCV) and the membrane bounded (dense) bodies (MBB). The latter are extremely numerous in pig pinealocytes (they occupy 6-20% of the cytoplasm), and the number of MBB changes under different physiological and experimental conditions. Norepinephrine is the main neurotransmitter that regulates the secretion of pineal melatonin. The present study was carried out to 1) clarify whether the DCV and their source - the Golgi apparatus (GA) - as well as the MBB are controlled by norepinephrine, 2) determine the effect of adrenergic stimulation on these structures, and 3) identify the receptors involved in the regulation of these structures. The studies were performed using a static organ culture of pig pineal explants. The explants were incubated in a control medium between 08:00 and 20:00 and in a medium with 10μM norepinephrine or alpha- or beta-adrenoceptor agonists between 20:00 and 08:00 on five consecutive days. The tissues were subsequently prepared for ultrastructural analysis. The results distinctly showed that the DCV, GA and MBB in pig pinealocytes are under adrenergic control. The stimulation of the beta-adrenoceptors resulted in an increase in the numerical density of the DCV and a decrease in the relative volume of the GA in the perikarya, while the incubation with agonists of the alpha1-adrenoceptors was ineffective. The relative volume of the MBB in the perikarya significantly decreased after treatment with both beta-agonists and alpha1-agonists, which suggested the involvement of two types of adrenoceptors in the regulation of these structures.
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Affiliation(s)
- Barbara Przybylska-Gornowicz
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Oczapowskiego 13 Str., 10-714 Olsztyn, Poland.
| | - Bogdan Lewczuk
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Oczapowskiego 13 Str., 10-714 Olsztyn, Poland
| | - Natalia Ziółkowska
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Oczapowskiego 13 Str., 10-714 Olsztyn, Poland
| | - Magdalena Prusik
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Oczapowskiego 13 Str., 10-714 Olsztyn, Poland
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8
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Wu Y, Cui L, Zhu E, Zhou W, Wang Q, Wu X, Wu B, Huang Y, Liu HJ. Muscovy duck reovirus σNS protein triggers autophagy enhancing virus replication. Virol J 2017; 14:53. [PMID: 28288679 PMCID: PMC5348909 DOI: 10.1186/s12985-017-0722-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 03/06/2017] [Indexed: 01/20/2023] Open
Abstract
Background Muscovy duck reovirus (MDRV) causes high morbidity and mortality in Muscovy ducklings at 10 days old and can persist in an infected flock until the ducklings of 6 weeks old. It shares common physicochemical properties with avian reovirus (ARV) and differs in coding assignment and pathogenicity. The ARV p17 protein has been shown to trigger autophagy via activation multiple signaling pathways, which benefits virus replication. Since MDRV lacks the p17 protein, whether and how MDRV induces autophagy remains unknown. The aim of this study was to explore whether MDRV induces autophagy and which viral proteins are involved in MDRV-induced autophagy. Methods The autophagosome-like structures in MDRV-infected cells was observed under transmission electron microscopy. MDRV-induced autophagy was examined by analyzing the LC3-II level and phosphorylated form of mammalian target of rapamycin (mTOR) by Western blot assays. The effects of 3-methyladenine, rapamycin, chloroquine on viral yields were measured with quantitative(q) real-time reverse transcription (RT)-polymerase chain reaction (PCR) and 50% tissue culture infective dose (TCID50) assays, respectively. Additionally, to determine which viral protein is responsible for MDRV-induced autophagy, both p10.8- and σNS-encoding genes of MDRV were cloned into the pCI-neo-flag vector and transfected into DF-1 cells for detection of LC3-II. Results The typical double-membrane vesicles containing cytoplasmic inclusions were visible in MDRV-infected immortalized chicken embryo fibroblast (DF-1) cells under transmission electron microscopy. Both primary Muscovy duck embryo fibroblasts (MDEF) and DF-1 cells infected with MDRV exhibited a significant increased levels of LC3-II accompanied with downregulation of phosphorylated form of mTOR, further confirming that MDRV is capable of inducing autophagy. Autophagy could be suppressed by 3-methylademine and induced by rapamycin and chloroquine. Furthermore, we found that σNS induces an increased levels of LC3-II, suggesting that the MDRV σNS protein is one of viral proteins involved in induction of autophagy. Both qRT-PCR and TCID50 assays showed that virus yield was increased in rapamycin treated DF-1 cells following MDRV infection. Conversely, when infected cells were pretreated with chloroquine, virus yield was decreased. Conclusions The MDRV σNS nonstructural protein is responsible for MDRV-induced autophagy and benefits virus replication.
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Affiliation(s)
- Yijian Wu
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, People's Republic of China.,Fujian Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health (Fujian Agricultural and Forestry University), Fuzhou, 350002, People's Republic of China
| | - Longping Cui
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, People's Republic of China
| | - Erpeng Zhu
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, People's Republic of China.,Fujian Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health (Fujian Agricultural and Forestry University), Fuzhou, 350002, People's Republic of China
| | - Wuduo Zhou
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, People's Republic of China.,Fujian Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health (Fujian Agricultural and Forestry University), Fuzhou, 350002, People's Republic of China
| | - Quanxi Wang
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, People's Republic of China.,Fujian Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health (Fujian Agricultural and Forestry University), Fuzhou, 350002, People's Republic of China
| | - Xiaoping Wu
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, People's Republic of China.,Fujian Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health (Fujian Agricultural and Forestry University), Fuzhou, 350002, People's Republic of China
| | - Baocheng Wu
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, People's Republic of China.,Fujian Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health (Fujian Agricultural and Forestry University), Fuzhou, 350002, People's Republic of China
| | - Yifan Huang
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, People's Republic of China.,Fujian Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health (Fujian Agricultural and Forestry University), Fuzhou, 350002, People's Republic of China
| | - Hung-Jen Liu
- Institute of Molecular Biology, National Chung Hsing University, Taichung, 402, Taiwan. .,Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung, 402, Taiwan. .,Agricultural Biotechnology Center, National Chung Hsing University, Taichung, 402, Taiwan.
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Knuppertz L, Osiewacz HD. Orchestrating the network of molecular pathways affecting aging: Role of nonselective autophagy and mitophagy. Mech Ageing Dev 2016; 153:30-40. [PMID: 26814678 DOI: 10.1016/j.mad.2016.01.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 01/08/2016] [Accepted: 01/20/2016] [Indexed: 12/28/2022]
Abstract
Autophagy is best known as a mechanism involved in cellular recycling of biomolecules during periods of nutritional starvation. More recently, an additional function of autophagy emerged: the selective degradation of functionally impaired or surplus proteins, organelles and invading bacteria. With this function autophagy is integrated in a network of pathways involved in molecular and cellular quality control with a key impact on development and aging. Impairments in the autophagic machinery lead to accelerated aging and the development of diseases. Here we focus on the role of nonselective autophagy and mitophagy, the selective autophagic degradation of mitochondria, on aging and lifespan of biological systems.
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Affiliation(s)
- Laura Knuppertz
- Institute of Molecular Biosciences and Cluster of Excellence Frankfurt Macromolecular Complexes, Department of Biosciences, J. W. Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Heinz D Osiewacz
- Institute of Molecular Biosciences and Cluster of Excellence Frankfurt Macromolecular Complexes, Department of Biosciences, J. W. Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany.
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10
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Nuclear localization of the p17 protein of avian reovirus is correlated with autophagy induction and an increase in viral replication. Arch Virol 2015; 160:3001-10. [PMID: 26350773 DOI: 10.1007/s00705-015-2598-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 09/02/2015] [Indexed: 12/17/2022]
Abstract
p17 is a nonstructural protein of avian reovirus (ARV) that induces autophagy in infected cells. In the present study, we investigated the effect of p17 and its nuclear localization signal (NLS) on autophagy and viral replication. When Vero cells and DF1 cells were transfected with mutant p17 in which lysine (K) at position 122 and arginine (R) at position 123 were mutated to alanine (A), the expression level of LC3 II decreased dramatically after transfection. The expression of the polypeptide encompassing the first 103 amino acids of p17, a region that did not contain the NLS, did not have a significant effect on autophagy. Moreover, when cells overexpressing mutant p17 were infected with the ARV GX2010/1 strain, the viral titer was significantly decreased compared with the expression of wild-type p17. In general, the NLS of p17 facilitates the induction of autophagy and is correlated with an increase in virus production.
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11
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Zhang Q, Zhu H, Xu X, Li L, Tan H, Cai X. Inactivated Sendai virus induces apoptosis and autophagy via the PI3K/Akt/mTOR/p70S6K pathway in human non-small cell lung cancer cells. Biochem Biophys Res Commun 2015; 465:64-70. [PMID: 26235873 DOI: 10.1016/j.bbrc.2015.07.130] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Accepted: 07/26/2015] [Indexed: 11/25/2022]
Abstract
Inactivated Sendai virus (HVJ-E) has shown potential anticancer efficacy in various cancer cells. However, the ability of HVJ-E to regulate cancer cell survival and death remains largely unknown. In the present study we first found that HVJ-E exhibited cytotoxic effects in the non-small cell lung cancer cell (NSCLC) line A549 and cisplatin-resistant A549 cells (A549/DDP). The suppression of cell viability was due to both the activation of caspases and the JNK and p38 MAPK signaling pathways in A549 and A549/DDP human lung cancer cells. In addition, we demonstrated that HVJ-E could induce autophagy in NSCLC cells via the PI3K/Akt/mTOR/p70S6K signaling pathway for the first time. Inhibiting autophagy in A549/DDP cells and inducing autophagy in A549 cells enhanced HVJ-E-induced apoptosis. These findings provide a molecular basis of HVJ-E-mediated cell death and support the notion that combination treatment with autophagy modulators is an effective strategy to augment the cytotoxic effects of HVJ-E in NSCLC cells.
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Affiliation(s)
- Quan Zhang
- Comparative Medicine Center, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, Jiangsu, China.
| | - Huixia Zhu
- Comparative Medicine Center, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, Jiangsu, China
| | - Xiaoshuang Xu
- Comparative Medicine Center, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, Jiangsu, China
| | - Lingyu Li
- Comparative Medicine Center, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, Jiangsu, China
| | - Haiming Tan
- Comparative Medicine Center, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, Jiangsu, China
| | - Xiaoyao Cai
- Comparative Medicine Center, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, Jiangsu, China
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Lin PY, Chang CD, Chen YC, Shih WL. RhoA/ROCK1 regulates Avian Reovirus S1133-induced switch from autophagy to apoptosis. BMC Vet Res 2015; 11:103. [PMID: 25944062 PMCID: PMC4430033 DOI: 10.1186/s12917-015-0417-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 04/26/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Autophagy is an essential process in the control of cellular homeostasis. It enables cells under certain stress conditions to survive by removing toxic cellular components, and may protect cells from apoptosis. In the present study, the signaling pathways involved in ARV S1133 regulated switch from autophagy to apoptosis were investigated. RESULTS ARV S1133 infection caused autophagy in the early to middle infectious stages in Vero and DF1 cells, and apoptosis in the middle to late stages. Conversion of the autophagy marker LC3-I to LC3-II occurred earlier than cleavage of the apoptotic marker caspase-3. ARV S1133 also activated the Beclin-1 promoter in the early to middle stages of infection. Levels of RhoA-GTP and ROCK1 activity were elevated upon ARV S1133 infection, while inhibition of RhoA and ROCK1 reduced autophagy and subsequent apoptosis. Conversely, inhibition of caspase-3 did not affect the level of autophagy. Beclin-1 knockdown and treatment with autophagy inhibitors, 3-MA and Bafilomycin A1, suppressed ARV S1133-induced autophagy and apoptosis simultaneously, suggesting the shift from autophagy to apoptosis. A co-immunoprecipitation assay demonstrated that the formation of a RhoA, ROCK1 and Beclin-1 complex coincided with the induction of autophagy. CONCLUSION Our results demonstrate that RhoA/ROCK1 signaling play critical roles in the transition of cell activity from autophagy to apoptosis in ARV S1133-infected cells.
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Affiliation(s)
- Ping-Yuan Lin
- Department of Biological Science and Technology, Pingtung, 91201, Taiwan.
| | - Ching-Dong Chang
- Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan.
| | - Yo-Chia Chen
- Department of Biological Science and Technology, Pingtung, 91201, Taiwan.
| | - Wen-Ling Shih
- Department of Biological Science and Technology, Pingtung, 91201, Taiwan. .,Graduate Institute of Biotechnology, National Pingtung University of Science and Technology, 1, Shuefu Rd., Neipu, Pingtung, 91201, Taiwan.
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Chumnanpuen P, Nookaew I, Nielsen J. Integrated analysis, transcriptome-lipidome, reveals the effects of INO-level (INO2 and INO4) on lipid metabolism in yeast. BMC SYSTEMS BIOLOGY 2013; 7 Suppl 3:S7. [PMID: 24456840 PMCID: PMC3852131 DOI: 10.1186/1752-0509-7-s3-s7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Background In the yeast Saccharomyces cerevisiae, genes containing UASINO sequences are regulated by the Ino2/Ino4 and Opi1 transcription factors, and this regulation controls lipid biosynthesis. The expression level of INO2 and INO4 genes (INO-level) at different nutrient limited conditions might lead to various responses in yeast lipid metabolism. Methods In this study, we undertook a global study on how INO-levels (transcription level of INO2 and INO4) affect lipid metabolism in yeast and we also studied the effects of single and double deletions of the two INO-genes (deficient effect). Using 2 types of nutrient limitations (carbon and nitrogen) in chemostat cultures operated at a fixed specific growth rate of 0.1 h-1 and strains having different INO-level, we were able to see the effect on expression level of the genes involved in lipid biosynthesis and the fluxes towards the different lipid components. Through combined measurements of the transcriptome, metabolome, and lipidome it was possible to obtain a large dataset that could be used to identify how the INO-level controls lipid metabolism and also establish correlations between the different components. Results In this study, we undertook a global study on how INO-levels (transcription level of INO2 and INO4) affect lipid metabolism in yeast and we also studied the effects of single and double deletions of the two INO-genes (deficient effect). Using 2 types of nutrient limitations (carbon and nitrogen) in chemostat cultures operated at a fixed specific growth rate of 0.1 h-1 and strains having different INO-level, we were able to see the effect on expression level of the genes involved in lipid biosynthesis and the fluxes towards the different lipid components. Through combined measurements of the transcriptome, metabolome, and lipidome it was possible to obtain a large dataset that could be used to identify how the INO-level controls lipid metabolism and also establish correlations between the different components. Conclusions Our analysis showed the strength of using a combination of transcriptome and lipidome analysis to illustrate the effect of INO-levels on phospholipid metabolism and based on our analysis we established a global regulatory map.
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Promotion of autophagy at the maturation step by IL-6 is associated with the sustained mitogen-activated protein kinase/extracellular signal-regulated kinase activity. Mol Cell Biochem 2013; 380:219-27. [PMID: 23677697 DOI: 10.1007/s11010-013-1676-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Accepted: 05/02/2013] [Indexed: 12/19/2022]
Abstract
Increased autophagic vacuoles (AVs) occur in injured or degenerating neurons, under both developmental and pathological situations. Although an induced autophagy has been shown in inflammation response to cell factors, the underlying mechanism(s) remain(s) unknown. Here, we show that both cell factor IL-6 and environmental toxin MPP(+) promote the formation of vacuolation in SHSY5Y cells. By electron and immunofluorescent microscopy analyses, we showed that these structures are acid autolysosomes, containing cellular debris, and labeled by LC3 or LAMP1, markers of autophagosomes or lysosomes, respectively. Combining MPP(+) and IL-6 do not further increase vacuolation of SHSY5Y cells, and the vacuolation is less than that in the MPP(+)-treated group. MPP(+)-induced vacuolation results from significant increase in autophagy formation and delay in autophagy degradation, in relation to a decline of the lysosomal activity of arylsulfatase A. At molecular level, we show that this defect in autolysosomal maturation is independent of mammalian target of rapamycin and p38 inhibitions. Most importantly, we provide the first evidence that activation of ERK pathway is sufficient to commit cell to autophagic vacuolation. The sustained activation is required for MPP(+) to disrupt the autophagic pathway. IL-6 also induces a temporary and significant activation of ERK, but not sustained activation, and change sustained activation in MPP(+)-treated group into temporary activation. Taken together, these findings strongly support that IL-6 promotes the maturation of autophagosomes into functional autolysosomes by regulating ERK.
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Penna F, Costamagna D, Pin F, Camperi A, Fanzani A, Chiarpotto EM, Cavallini G, Bonelli G, Baccino FM, Costelli P. Autophagic degradation contributes to muscle wasting in cancer cachexia. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 182:1367-78. [PMID: 23395093 DOI: 10.1016/j.ajpath.2012.12.023] [Citation(s) in RCA: 180] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 12/11/2012] [Accepted: 12/31/2012] [Indexed: 11/26/2022]
Abstract
Muscle protein wasting in cancer cachexia is a critical problem. The underlying mechanisms are still unclear, although the ubiquitin-proteasome system has been involved in the degradation of bulk myofibrillar proteins. The present work has been aimed to investigate whether autophagic degradation also plays a role in the onset of muscle depletion in cancer-bearing animals and in glucocorticoid-induced atrophy and sarcopenia of aging. The results show that autophagy is induced in muscle in three different models of cancer cachexia and in glucocorticoid-treated mice. In contrast, autophagic degradation in the muscle of sarcopenic animals is impaired but can be reactivated by calorie restriction. These results further demonstrate that different mechanisms are involved in pathologic muscle wasting and that autophagy, either excessive or defective, contributes to the complicated network that leads to muscle atrophy. In this regard, particularly intriguing is the observation that in cancer hosts and tumor necrosis factor α-treated C2C12 myotubes, insulin can only partially blunt autophagy induction. This finding suggests that autophagy is triggered through mechanisms that cannot be circumvented by using classic upstream modulators, prompting us to identify more effective approaches to target this proteolytic system.
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Affiliation(s)
- Fabio Penna
- Department of Clinical and Biological Sciences, University of Torino, 10125 Torino, Italy
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16
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ABE AKIHISA, KOKUBA HIROKO. Harmol induces autophagy and subsequent apoptosis in U251MG human glioma cells through the downregulation of survivin. Oncol Rep 2013; 29:1333-42. [DOI: 10.3892/or.2013.2242] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 11/12/2012] [Indexed: 11/06/2022] Open
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17
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Meng S, Jiang K, Zhang X, Zhang M, Zhou Z, Hu M, Yang R, Sun C, Wu Y. Avian reovirus triggers autophagy in primary chicken fibroblast cells and Vero cells to promote virus production. Arch Virol 2012; 157:661-8. [PMID: 22241622 DOI: 10.1007/s00705-012-1226-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Accepted: 12/06/2011] [Indexed: 12/14/2022]
Abstract
Avian reovirus (ARV) is an important cause of disease in poultry. Although ARV is known to induce apoptosis in infected cells, the interaction between ARV and its target cells requires further elucidation. In this report, we show that the ARV isolate strain GX/2010/1 induces autophagy in both Vero and primary chicken embryonic fibroblast (CEF) cells based on the appearance of an increased number of double-membrane vesicles, the presence of GFP-microtubule-associated protein 1 light chain 3 (GFP-LC3) dot formation, and the elevated production of LC3II. We further demonstrate that the class I phosphoinositide 3-kinase (PI3K)/Akt/mTOR pathway contributes to autophagic induction by ARV infection. Moreover, treatment of ARV-infected cells with the autophagy inducer rapamycin increased viral yields, while inhibition of the autophagosomal pathway using chloroquine led to a decrease in virus production. Altogether, our studies strongly suggest that autophagy may play a critical role in determining viral yield during ARV infection.
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Affiliation(s)
- Songshu Meng
- Ministry of Education Key Lab for Avian Preventive Medicine, College of Veterinary Medicine, Yangzhou University, Wenhuidong Road No. 48, Yangzhou, 225009, China.
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Induction of an incomplete autophagic response by cancer-preventive geranylgeranoic acid (GGA) in a human hepatoma-derived cell line. Biochem J 2011; 440:63-71. [DOI: 10.1042/bj20110610] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
GGA (geranylgeranoic acid) is a natural polyprenoic acid, derivatives of which has been shown to prevent second primary hepatoma. GGA induces mitochondria-mediated PCD (programmed cell death), which may be relevant to cancer prevention. To gain further insights into GGA-induced PCD, autophagy processes were examined in human hepatoma-derived HuH-7 cells. Treatment of HuH-7/GFP (green fluorescent protein)–LC3 cells with GGA induced green fluorescent puncta in the cytoplasm within 30 min and their massive accumulation at 24 h. After 15 min of GGA treatment, a burst of mitochondrial superoxide production occurred and LC3β-I was appreciably converted into LC3β-II. GGA-induced early stages of autophagy were unequivocally confirmed by electron-microscopic observation of early/initial autophagic vacuoles. On the other hand, LC3β-II as well as p62/SQSTM1 (sequestosome 1) continuously accumulated and co-localized in the cytoplasmic puncta after GGA treatment. Furthermore, GGA treatment of HuH-7/mRFP (monomeric red fluorescent protein)–GFP–LC3 cells showed yellow fluorescent puncta, whereas glucose deprivation of the cells gave red fluorescent puncta. These results strongly suggest that GGA induces the initial phase of autophagy, but blocks the maturation process of autolysosomes or late stages of autophagy, insomuch that GGA provides substantial accumulation of autophagosomes under serum-starvation conditions in human hepatoma cells.
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Abe A, Yamada H, Moriya S, Miyazawa K. The .BETA.-Carboline Alkaloid Harmol Induces Cell Death via Autophagy but Not Apoptosis in Human Non-small Cell Lung Cancer A549 Cells. Biol Pharm Bull 2011; 34:1264-72. [DOI: 10.1248/bpb.34.1264] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Akihisa Abe
- Department of Biochemistry, Tokyo Medical University
| | - Hiroyuki Yamada
- Bacteriology Division, Mycobacterium Reference Center, Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association (JATA)
| | - Shota Moriya
- Department of Biochemistry, Tokyo Medical University
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Ravikumar B, Sarkar S, Davies JE, Futter M, Garcia-Arencibia M, Green-Thompson ZW, Jimenez-Sanchez M, Korolchuk VI, Lichtenberg M, Luo S, Massey DCO, Menzies FM, Moreau K, Narayanan U, Renna M, Siddiqi FH, Underwood BR, Winslow AR, Rubinsztein DC. Regulation of mammalian autophagy in physiology and pathophysiology. Physiol Rev 2010; 90:1383-435. [PMID: 20959619 DOI: 10.1152/physrev.00030.2009] [Citation(s) in RCA: 1340] [Impact Index Per Article: 95.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
(Macro)autophagy is a bulk degradation process that mediates the clearance of long-lived proteins and organelles. Autophagy is initiated by double-membraned structures, which engulf portions of cytoplasm. The resulting autophagosomes ultimately fuse with lysosomes, where their contents are degraded. Although the term autophagy was first used in 1963, the field has witnessed dramatic growth in the last 5 years, partly as a consequence of the discovery of key components of its cellular machinery. In this review we focus on mammalian autophagy, and we give an overview of the understanding of its machinery and the signaling cascades that regulate it. As recent studies have also shown that autophagy is critical in a range of normal human physiological processes, and defective autophagy is associated with diverse diseases, including neurodegeneration, lysosomal storage diseases, cancers, and Crohn's disease, we discuss the roles of autophagy in health and disease, while trying to critically evaluate if the coincidence between autophagy and these conditions is causal or an epiphenomenon. Finally, we consider the possibility of autophagy upregulation as a therapeutic approach for various conditions.
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Affiliation(s)
- Brinda Ravikumar
- Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Addenbrooke’s Hospital, Cambridge, United Kingdom
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Abstract
Programmed cell death (PCD) occurs widely in species from every kingdom of life. It has been shown to be an integral aspect of development in multicellular organisms, and it is an essential component of the immune response to infectious agents. An analysis of the phylogenetic origin of PCD now shows that it evolved independently several times, and it is fundamental to basic cellular physiology. Undoubtedly, PCD pervades all life at every scale of analysis. These considerations provide a backdrop for understanding the complexity of intertwined, but independent, cell death programs that operate within the immune system. In particular, the contributions of apoptosis, autophagy, and necrosis in the resolution of an immune response are considered.
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Affiliation(s)
- Stephen M Hedrick
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093-0377, USA.
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Moriceau G, Ory B, Mitrofan L, Riganti C, Blanchard F, Brion R, Charrier C, Battaglia S, Pilet P, Denis MG, Shultz LD, Mönkkönen J, Rédini F, Heymann D. Zoledronic acid potentiates mTOR inhibition and abolishes the resistance of osteosarcoma cells to RAD001 (Everolimus): pivotal role of the prenylation process. Cancer Res 2010; 70:10329-39. [PMID: 20971812 DOI: 10.1158/0008-5472.can-10-0578] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Despite recent improvements in therapeutic management of osteosarcoma, ongoing challenges in improving the response to chemotherapy warrants new strategies still needed to improve overall patient survival. In this study, we investigated in vivo the effects of RAD001 (Everolimus), a new orally available mTOR inhibitor, on the growth of human and mouse osteosarcoma cells either alone or in combination with zoledronate (ZOL), an anti-osteoporotic drug used to treat bone metastases. RAD001 inhibited osteosarcoma cell proliferation in a dose- and time-dependent manner with no modification of cell-cycle distribution. Combination with ZOL augmented this inhibition of cell proliferation, decreasing PI3K/mTOR signaling compared with single treatments. Notably, in contrast to RAD001, ZOL downregulated isoprenylated membrane-bound Ras concomitantly with an increase of nonisoprenylated cytosolic Ras in sensitive and resistant osteosarcoma cell lines to both drugs. Moreover, ZOL and RAD001 synergized to decrease Ras isoprenylation and GTP-bound Ras levels. Further, the drug combination reduced tumor development in two murine models of osteoblastic or osteolytic osteosarcoma. We found that ZOL could reverse RAD001 resistance in osteosarcoma, limiting osteosarcoma cell growth in combination with RAD001. Our findings rationalize further study of the applications of mTOR and mevalonate pathway inhibitors that can limit protein prenylation pathways.
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Protein kinase C inhibits autophagy and phosphorylates LC3. Biochem Biophys Res Commun 2010; 395:471-6. [PMID: 20398630 DOI: 10.1016/j.bbrc.2010.04.030] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 04/05/2010] [Indexed: 01/12/2023]
Abstract
During autophagy, the microtubule-associated protein light chain 3 (LC3), a specific autophagic marker in mammalian cells, is processed from the cytosolic form (LC3-I) to the membrane-bound form (LC3-II). In HEK293 cells stably expressing FLAG-tagged LC3, activation of protein kinase C inhibited the autophagic processing of LC3-I to LC3-II induced by amino acid starvation or rapamycin. PKC inhibitors dramatically induced LC3 processing and autophagosome formation. Unlike autophagy induced by starvation or rapamycin, PKC inhibitor-induced autophagy was not blocked by the PI-3 kinase inhibitor wortmannin. Using orthophosphate metabolic labeling, we found that LC3 was phosphorylated in response to the PKC activator PMA or the protein phosphatase inhibitor calyculin A. Furthermore, bacterially expressed LC3 was directly phosphorylated by purified PKC in vitro. The sites of phosphorylation were mapped to T6 and T29 by nanoLC-coupled tandem mass spectrometry. Mutations of these residues significantly reduced LC3 phosphorylation by purified PKC in vitro. However, in HEK293 cells stably expressing LC3 with these sites mutated either singly or doubly to Ala, Asp or Glu, autophagy was not significantly affected, suggesting that PKC regulates autophagy through a mechanism independent of LC3 phosphorylation.
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Berezniuk I, Sironi J, Callaway MB, Castro LM, Hirata IY, Ferro ES, Fricker LD. CCP1/Nna1 functions in protein turnover in mouse brain: Implications for cell death in Purkinje cell degeneration mice. FASEB J 2010; 24:1813-23. [PMID: 20061535 DOI: 10.1096/fj.09-147942] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Purkinje cell degeneration (pcd) mice have a mutation within the gene encoding cytosolic carboxypeptidase 1 (CCP1/Nna1), which has homology to metallocarboxypeptidases. To assess the function of CCP1/Nna1, quantitative proteomics and peptidomics approaches were used to compare proteins and peptides in mutant and wild-type mice. Hundreds of peptides derived from cytosolic and mitochondrial proteins are greatly elevated in pcd mouse hypothalamus, amygdala, cortex, prefrontal cortex, and striatum. However, the major proteins detected on 2-D gel electrophoresis were present in mutant and wild-type mouse cortex and hypothalamus at comparable levels, and proteasome activity is normal in these brain regions of pcd mice, suggesting that the increase in cellular peptide levels in the pcd mice is due to reduced degradation of the peptides downstream of the proteasome. Both nondegenerating and degenerating regions of pcd mouse brain, but not wild-type mouse brain, show elevated autophagy, which can be triggered by a decrease in amino acid levels. Taken together with previous studies on CCP1/Nna1, these data suggest that CCP1/Nna1 plays a role in protein turnover by cleaving proteasome-generated peptides into amino acids and that decreased peptide turnover in the pcd mice leads to cell death.
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Affiliation(s)
- Iryna Berezniuk
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Coxiella burnetii modulates Beclin 1 and Bcl-2, preventing host cell apoptosis to generate a persistent bacterial infection. Cell Death Differ 2009; 17:421-38. [DOI: 10.1038/cdd.2009.129] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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Halapas A, Armakolas A, Koutsilieris M. Autophagy: a target for therapeutic interventions in myocardial pathophysiology. Expert Opin Ther Targets 2009; 12:1509-22. [PMID: 19007320 DOI: 10.1517/14728220802555554] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Autophagy is a major degradative and highly conserved process in eukaryotic cells that is activated by stress signals. This self-cannibalisation is activated as a response to changing environmental conditions, cellular remodelling during development and differentiation, and maintenance of homeostasis. OBJECTIVE To review autophagy regarding its process, molecular mechanisms and regulation in mammalian cells, and its role in myocardial pathophysiology. RESULTS/CONCLUSION Autophagy is a multistep process regulated by diverse, intracellular and/or extracellular signalling complexes and pathways. In the heart, normally, autophagy occurs at low basal levels, where it represents a homeostatic mechanism for the maintenance of cardiac function and morphology. However, in the diseased heart the functional role of the enhanced autophagy is unclear and studies have yielded conflicting results. Recently, it was shown that during myocardial ischemia autophagy promotes survival by maintaining energy homeostasis. Also, rapamycin was demonstrated to prevent cardiac hypertrophy. In heart failure, upregulation of autophagy acts as an adaptive response that protects cells from hemodynamic stress. In addition, sirolimus-eluting stents have been shown to lower re-stenosis rates in patients with coronary artery disease after angioplasty. Thus, this mechanism can become a major target for therapeutic intervention in heart pathophysiology.
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Affiliation(s)
- Antonis Halapas
- National and Kapodistrian University of Athens, Medical School, Department of Experimental Physiology, Goudi-Athens, Greece
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28
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Choi SE, Lee SM, Lee YJ, Li LJ, Lee SJ, Lee JH, Kim Y, Jun HS, Lee KW, Kang Y. Protective role of autophagy in palmitate-induced INS-1 beta-cell death. Endocrinology 2009; 150:126-34. [PMID: 18772242 DOI: 10.1210/en.2008-0483] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Autophagy, a vacuolar degradative pathway, constitutes a stress adaptation that avoids cell death or elicits the alternative cell-death pathway. This study was undertaken to determine whether autophagy is activated in palmitate (PA)-treated beta-cells and, if activated, what the role of autophagy is in the PA-induced beta-cell death. The enhanced formation of autophagosomes and autolysosomes was observed by exposure of INS-1 beta-cells to 400 microm PA in the presence of 25 mm glucose for 12 h. The formation of green fluorescent protein-LC3-labeled structures (green fluorescent protein-LC3 dots), with the conversion from LC3-I to LC3-II, was also distinct in the PA-treated cells. The phospho-mammalian target of rapamycin level, a typical signal pathway that inhibits activation of autophagy, was gradually decreased by PA treatment. Blockage of the mammalian target of rapamycin signaling pathway by treatment with rapamycin augmented the formation of autophagosomes but reduced PA-induced INS-1 cell death. In contrast, reduction of autophagosome formation by knocking down the ATG5, inhibition of fusion between autophagosome and lysosome by treatment with bafilomycin A1, or inhibition of proteolytic degradation by treatment with E64d/pepstatin A, significantly augmented PA-induced INS-1 cell death. These findings showed that the autophagy system could be activated in PA-treated INS-1 beta-cells, and suggested that the induction of autophagy might play an adaptive and protective role in PA-induced cell death.
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Affiliation(s)
- Sung-E Choi
- Institute for Medical Science, Ajou University School of Medicine, Wonchon-dong san5, Yongtong-gu, Suwon, Gyeonggi-do 442-749, Republic of Korea
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Membrane proteomics of phagosomes suggests a connection to autophagy. Proc Natl Acad Sci U S A 2008; 105:16952-7. [PMID: 18971338 DOI: 10.1073/pnas.0809218105] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Phagocytosis is the central process by which macrophage cells internalize and eliminate infectious microbes as well as apoptotic cells. During maturation, phagosomes containing engulfed particles fuse with various endosomal compartments through the action of regulatory molecules on the phagosomal membrane. In this study, we performed a proteomic analysis of the membrane fraction from latex bead-containing (LBC) phagosomes isolated from macrophages. The profile, which comprised 546 proteins, suggests diverse functions of the phagosome and potential connections to secretory processes, toll-like receptor signaling, and autophagy. Many identified proteins were not previously known to reside in the phagosome. We characterized several proteins in LBC phagosomes that change in abundance on induction of autophagy, a process that has been previously implicated in the host defense against microbial pathogens. These observations suggest crosstalk between autophagy and phagocytosis that may be relevant to the innate immune response of macrophages.
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Ghiglione HO, Gonzalez FG, Serrago R, Maldonado SB, Chilcott C, Curá JA, Miralles DJ, Zhu T, Casal JJ. Autophagy regulated by day length determines the number of fertile florets in wheat. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 55:1010-24. [PMID: 18547393 DOI: 10.1111/j.1365-313x.2008.03570.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The wheat spikelet meristem differentiates into up to 12 floret primordia, but many of them fail to reach the fertile floret stage at anthesis. We combined microarray, biochemical and anatomical studies to investigate floret development in wheat plants grown in the field under short or long days (short days extended with low-fluence light) after all the spikelets had already differentiated. Long days accelerated spike and floret development and greening, and the expression of genes involved in photosynthesis, photoprotection and carbohydrate metabolism. These changes started while the spike was in the light-depleted environment created by the surrounding leaf sheaths. Cell division ceased in the tissues of distal florets, which interrupted their normal developmental progression and initiated autophagy, thus decreasing the number of fertile florets at anthesis. A massive decrease in the expression of genes involved in cell proliferation, a decrease in soluble carbohydrate levels, and an increase in the expression of genes involved in programmed cell death accompanied anatomical signs of cell death, and these effects were stronger under long days. We propose a model in which developmentally generated sugar starvation triggers floret autophagy, and long days intensify these processes due to the increased carbohydrate consumption caused by the accelerated plant development.
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Affiliation(s)
- Hernán O Ghiglione
- Bioquímica, Facultad de Agronomía, Universidad de Buenos Aires, Av San Martín 4453, 1417 Buenos Aires, Argentina
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Abstract
A host of dietary factors can influence various cellular processes and thereby potentially influence overall cancer risk and tumor behavior. In many cases, these factors suppress cancer by stimulating programmed cell death. However, death not only can follow the well-characterized type I apoptotic pathway but also can proceed by nonapoptotic modes such as type II (macroautophagy-related) and type III (necrosis) or combinations thereof. In contrast to apoptosis, the induction of macroautophagy may contribute to either the survival or death of cells in response to a stressor. This review highlights current knowledge and gaps in our understanding of the interactions among bioactive food constituents, autophagy, and cancer. Whereas a variety of food components including vitamin D, selenium, curcumin, resveratrol, and genistein have been shown to stimulate autophagy vacuolization, it is often difficult to determine if this is a protumorigenic or antitumorigenic response. Additional studies are needed to examine dose and duration of exposures and tissue specificity in response to bioactive food components in transgenic and knockout models to resolve the physiologic implications of early changes in the autophagy process.
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Affiliation(s)
- Keith Singletary
- Department of Food Science and Human Nutrition, University of Illinois, Urbana, IL 61801, USA.
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Kundu M, Thompson CB. Autophagy: basic principles and relevance to disease. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2008; 3:427-55. [PMID: 18039129 DOI: 10.1146/annurev.pathmechdis.2.010506.091842] [Citation(s) in RCA: 410] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Autophagy is a process by which cytoplasmic components are sequestered in double membrane vesicles and degraded upon fusion with lysosomal compartments. In yeast, autophagy is activated in response to changes in the extracellular milieu. Depending upon the stimulus, autophagy can degrade cytoplasmic contents nonspecifically or can target the degradation of specific cellular components. Both of these have been adopted in higher eukaryotes and account for the expanding role of autophagy in various cellular processes, as well as contribute to the variation in cellular outcomes after induction of autophagy. In some cases, autophagy appears to be an adaptive response, whereas under other circumstances it is involved in cell death. In mammals, autophagy has been implicated in either the pathogenesis or response to a wide variety of diseases, including neurodegenerative disease, chronic bacterial and viral infections, atherosclerosis, and cancer. As the basic molecular pathways that regulate autophagy are elucidated, the relationship of autophagy to the pathogenesis of various disease states emerges.
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Affiliation(s)
- Mondira Kundu
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19063, USA.
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Kim I, Rodriguez-Enriquez S, Lemasters JJ. Selective degradation of mitochondria by mitophagy. Arch Biochem Biophys 2007; 462:245-53. [PMID: 17475204 PMCID: PMC2756107 DOI: 10.1016/j.abb.2007.03.034] [Citation(s) in RCA: 1202] [Impact Index Per Article: 70.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Accepted: 03/25/2007] [Indexed: 12/14/2022]
Abstract
Mitochondria are the essential site of aerobic energy production in eukaryotic cells. Reactive oxygen species (ROS) are an inevitable by-product of mitochondrial metabolism and can cause mitochondrial DNA mutations and dysfunction. Mitochondrial damage can also be the consequence of disease processes. Therefore, maintaining a healthy population of mitochondria is essential to the well-being of cells. Autophagic delivery to lysosomes is the major degradative pathway in mitochondrial turnover, and we use the term mitophagy to refer to mitochondrial degradation by autophagy. Although long assumed to be a random process, increasing evidence indicates that mitophagy is a selective process. This review provides an overview of the process of mitophagy, the possible role of the mitochondrial permeability transition in mitophagy and the importance of mitophagy in turnover of dysfunctional mitochondria.
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Affiliation(s)
- Insil Kim
- Center for Cell Death, Injury and Regeneration, Departments of Pharmaceutical Sciences and Biochemistry & Molecular Biology, Medical University of South Carolina
- Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | | | - John J. Lemasters
- Center for Cell Death, Injury and Regeneration, Departments of Pharmaceutical Sciences and Biochemistry & Molecular Biology, Medical University of South Carolina
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Ernst J, Vainas O, Harbison CT, Simon I, Bar-Joseph Z. Reconstructing dynamic regulatory maps. Mol Syst Biol 2007; 3:74. [PMID: 17224918 PMCID: PMC1800355 DOI: 10.1038/msb4100115] [Citation(s) in RCA: 160] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Accepted: 11/15/2006] [Indexed: 02/07/2023] Open
Abstract
Even simple organisms have the ability to respond to internal and external stimuli. This response is carried out by a dynamic network of protein-DNA interactions that allows the specific regulation of genes needed for the response. We have developed a novel computational method that uses an input-output hidden Markov model to model these regulatory networks while taking into account their dynamic nature. Our method works by identifying bifurcation points, places in the time series where the expression of a subset of genes diverges from the rest of the genes. These points are annotated with the transcription factors regulating these transitions resulting in a unified temporal map. Applying our method to study yeast response to stress, we derive dynamic models that are able to recover many of the known aspects of these responses. Predictions made by our method have been experimentally validated leading to new roles for Ino4 and Gcn4 in controlling yeast response to stress. The temporal cascade of factors reveals common pathways and highlights differences between master and secondary factors in the utilization of network motifs and in condition-specific regulation.
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Affiliation(s)
- Jason Ernst
- Machine Learning Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Oded Vainas
- Department of Molecular Biology, Hebrew University Medical School, Jerusalem, Israel
| | | | - Itamar Simon
- Department of Molecular Biology, Hebrew University Medical School, Jerusalem, Israel
| | - Ziv Bar-Joseph
- Machine Learning Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, USA
- Department of Computer Science, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, USA
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35
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Zhu JH, Horbinski C, Guo F, Watkins S, Uchiyama Y, Chu CT. Regulation of autophagy by extracellular signal-regulated protein kinases during 1-methyl-4-phenylpyridinium-induced cell death. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 170:75-86. [PMID: 17200184 PMCID: PMC1762689 DOI: 10.2353/ajpath.2007.060524] [Citation(s) in RCA: 357] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/13/2006] [Indexed: 01/19/2023]
Abstract
Increased autophagic vacuoles (AVs) occur in injured or degenerating neurons, under both developmental and pathological situations. Although regulation of starvation-induced autophagy has been extensively studied, less is known about autophagic responses to pathological damage. The neurotoxin 1-methyl-4-phenylpyridinium (MPP(+)) produces mitochondria-targeted injury, which contributes to parkinsonism induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydro-pyridine in mammals. Here, we demonstrate that MPP(+) elicited increased autophagy in SH-SY5Y cells, as assessed by electron microscopy, immunofluorescence for the autophagy protein LC3/Atg8, LC3 electrophoretic mobility shift, mitochondrial degradation, and monodansylcadaverine staining for late AVs/autolysosomes. During nutrient deprivation, class III phosphatidylinositol-3 kinase (PI3K) stimulates autophagy in concert with the autophagy-regulatory protein beclin 1/Atg6. Although PI3K inhibitors and RNA interference knockdown of beclin 1 effectively inhibited autophagy elicited by amino acid deprivation, neither reduced MPP+-induced autophagic stress. In contrast, inhibition of mitogen-activated protein kinase/extracellular signal-regulated protein kinase kinase reduced AV content, mitochondrial degradation, and cell death in MPP+-treated cells. RNA interference studies targeting core Atg proteins also reduced AV content and cell death. Likewise, in primary midbrain dopaminergic neurons, MPP+ elicited increased AV content, which was reversed by inhibition of mitogen-activated protein kinase/extracellular signal-regulated protein kinase kinase but not PI3K. These results implicate a role for extracellular signal-regulated protein kinase (ERK) signaling upstream of MPP+-elicited autophagic stress. Moreover, pathological stimulation of beclin 1-independent autophagy is associated with neuronal cell death.
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Affiliation(s)
- Jian-Hui Zhu
- Department of Pathology/Division of Neuropathology, Pittsburgh Institute for Neurodegenerative Diseases, Center for Biologic Imaging, Pittsburgh, PA, USA
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36
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Corcelle E, Nebout M, Bekri S, Gauthier N, Hofman P, Poujeol P, Fénichel P, Mograbi B. Disruption of autophagy at the maturation step by the carcinogen lindane is associated with the sustained mitogen-activated protein kinase/extracellular signal-regulated kinase activity. Cancer Res 2006; 66:6861-70. [PMID: 16818664 DOI: 10.1158/0008-5472.can-05-3557] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Macroautophagy (hereafter referred to as autophagy) has emerged as a key tumor suppressor pathway. During this process, the cytosolic constituents are sequestered into autophagosomes, which subsequently fuse with lysosomes to become autolysosomes where their contents are finally degraded. Although a reduced autophagy has been shown in human tumors or in response to oncogenes and carcinogens, the underlying mechanism(s) remain(s) unknown. Here, we show that widely used carcinogen Lindane promotes vacuolation of Sertoli cells. By electron and immunofluorescent microscopy analyses, we showed that these structures are acid autolysosomes, containing cellular debris, and labeled by LC3, Rab7, and LAMP1, markers of autophagosomes, late endosomes, and lysosomes, respectively. Such Lindane-induced vacuolation results from significant delay in autophagy degradation, in relation with a decline of the lysosomal activity of aryl sulfatase A. At molecular level, we show that this defect in autolysosomal maturation is independent of mammalian target of rapamycin and p38 inhibitions. Rather, the activation of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway is required for Lindane to disrupt the autophagic pathway. Most importantly, we provide the first evidence that sustained activation of ERK pathway is sufficient to commit cell to autophagic vacuolation. Taken together, these findings strongly support that the aberrant sustained activation of ERK by the carcinogen Lindane disrupts the maturation of autophagosomes into functional autolysosomes. Our findings therefore suggest the possibility that high constitutive ERK activity found in all cancers may provide a malignant advantage by impeding the tumor suppressive function of autophagy.
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Affiliation(s)
- Elisabeth Corcelle
- Institut National de la Santé et de la Recherche Médicale U670, IFR 50, Faculté de Médecine, Avenue de Valombrose, 06107 Nice Cedex 02, France
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Katayama M, Kawaguchi T, Berger MS, Pieper RO. DNA damaging agent-induced autophagy produces a cytoprotective adenosine triphosphate surge in malignant glioma cells. Cell Death Differ 2006; 14:548-58. [PMID: 16946731 DOI: 10.1038/sj.cdd.4402030] [Citation(s) in RCA: 268] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Although autophagy enhances cell survival in nutrient-deprived cells by increasing adenosine triphosphate (ATP) production, it remains unclear if autophagy functions similarly in cells treated with cytotoxic chemotherapy agents. To address this issue, we measured both the ability of DNA damaging agents (Temozolomide, and Etoposide) to induce an autophagy-dependent production of ATP, and the effects of modulation of autophagy on drug-induced cell death. Both drugs induced an autophagy-associated increase in ATP production in multiple glioma cell lines. The drug-induced ATP surge could not be blocked by glucose starvation, but could be blocked by preincubation with the autophagy inhibitor 3-methyladenine (3-MA), an siRNA targeting beclin 1, or the mitochondrial inhibitor oligomycin. Inhibition of autophagy-induced ATP production increased non-apoptotic cell death associated with micronucleation, while restoration of the 3-MA-inhibited ATP surge by addition of pyruvate suppressed cell death. These results show that DNA damaging agents induce an autophagy-associated ATP surge that protects cells and may contribute to drug resistance.
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Affiliation(s)
- M Katayama
- Department of Neurological Surgery, Brain Tumor Research Center, University of California, San Francisco, CA 94115-0875, USA
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Kotoulas OB, Kalamidas SA, Kondomerkos DJ. Glycogen autophagy in glucose homeostasis. Pathol Res Pract 2006; 202:631-8. [PMID: 16781826 DOI: 10.1016/j.prp.2006.04.001] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Accepted: 04/10/2006] [Indexed: 10/24/2022]
Abstract
Glycogen autophagy, the sequestration and degradation of cell glycogen in the autophagic vacuoles, is a selective, hormonally controlled and highly regulated process, representing a mechanism of glucose homeostasis under conditions of demand for the production of this sugar. In the newborn animals, this process is induced by glucagon secreted during the postnatal hypoglycemia and inhibited by insulin and parenteral glucose, which abolishes glucagon secretion. Hormonal action is mediated by the cAMP/protein kinase A (induction) and phosphoinositides/mTOR (inhibition) pathways that converge on common targets, such as the protein phosphatase 2A to regulate autophgosomal glycogen-hydrolyzing acid glucosidase and glycogen autophagy. Intralysosomal phosphate exchange reactions, which are affected by changes in the calcium levels and acid mannose 6- and acid glucose 6-phosphatase activities, can modify the intralysosomal composition in phosphorylated and nonphosphorylated glucose and promote the exit of free glucose through the lysosomal membrane. Glycogen autophagy-derived nonphosphorylated glucose assists the hyaloplasmic glycogen degradation-derived glucose 6-phosphate to combat postnatal hypoglycemia and participates in other metabolic pathways to secure the fine tuning of glucose homeostasis during the neonatal period.
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Affiliation(s)
- O B Kotoulas
- Department of Anatomy, Histology and Embryology, Medical School, University of Ioannina, Ioannina, Greece.
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de Chastellier C, Thilo L. Cholesterol depletion in Mycobacterium avium-infected macrophages overcomes the block in phagosome maturation and leads to the reversible sequestration of viable mycobacteria in phagolysosome-derived autophagic vacuoles. Cell Microbiol 2006; 8:242-56. [PMID: 16441435 DOI: 10.1111/j.1462-5822.2005.00617.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phagocytic entry of mycobacteria into macrophages requires the presence of cholesterol in the plasma membrane. This suggests that pathogenic mycobacteria may require cholesterol for their subsequent intra-cellular survival in non-maturing phagosomes. Here we report on the effect of cholesterol depletion on pre-existing phagosomes in mouse bone marrow-derived macrophages infected with Mycobacterium avium. Cholesterol depletion with methyl-beta-cyclodextrin resulted in a loosening of the close apposition between the phagosome membrane and the mycobacterial surface, followed by fusion with lysosomes. The resulting phagolysosomes then autonomously executed autophagy, which did not involve the endoplasmic reticulum. After 5 h of depletion, intact mycobacteria had accumulated in large auto-phagolysosomes. Autophagy was specific for phagolysosomes that contained mycobacteria, as it did not involve latex bead-containing phagosomes in infected cells. Upon replenishment of cholesterol, mycobacteria became increasingly aligned to the lysosomal membrane, from where they were individually sequestered in phagosomes with an all-around closely apposed phagosome membrane and which no longer fused with lysosomes. These observations indicate that, cholesterol depletion (i) resulted in phagosome maturation and fusion with lysosomes and (ii) caused mycobacterium-containing phagolysosomes to autonomously undergo autophagy. Furthermore, (iii) mycobacteria were not killed in auto-phagolysosomes, and (iv) cholesterol replenishment enabled mycobacterium to rescue itself from autophagic phagolysosomes to again reside individually in phagosomes which no longer fused with lysosomes.
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Affiliation(s)
- Chantal de Chastellier
- Centre d'Immunologie de Marseille-Luminy, INSERM-CNRS-Université de la Méditerranée, Marseille, France.
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40
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Abstract
Autophagy is a major cellular pathway for the degradation of long-lived proteins and cytoplasmic organelles in eukaryotic cells. A large number of intracellular/extracellular stimuli, including amino acid starvation and invasion of microorganisms, are able to induce the autophagic response in cells. The discovery of the ATG genes in yeast has greatly advanced our understanding of the molecular mechanisms participating in autophagy and the genes involved in regulating the autophagic pathway. Many yeast genes have mammalian homologs, suggesting that the basic machinery for autophagy has been evolutionarily conserved along the eukaryotic phylum. The regulation of autophagy is a very complex process. Many signaling pathways, including target of rapamycin (TOR) or mammalian target of rapamycin (mTOR), phosphatidylinositol 3-kinase-I (PI3K-I)/PKB, GTPases, calcium and protein synthesis all play important roles in regulating autophagy. The molecular mechanisms and regulation of autophagy are discussed in this review.
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Affiliation(s)
- Ya-Ping Yang
- Department of Pharmacology, Soochow University School of Medicine, Suzhou 215007, China
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41
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Abstract
Autophagy is a major intracellular pathway for the degradation and recycling of long-lived proteins and cytoplasmic organelles. Like apoptotic programmed cell death, autophagy is an essential part of growth regulation and maintenance of homeostasis in multicellular organisms. Autophagic vacuole formation is also activated as an adaptive response to a variety of extracellular and intracellular stimuli, including nutrient deprivation, hormonal or therapeutic treatment, bacterial infection, aggregated and misfolded proteins and damaged organelles. Mediators of class I and class III PI3 kinase signaling pathways and trimeric G proteins play major roles in regulating autophagosome formation during the stress response. Defective autophagy is the underlying cause of a number of pathological conditions, including vacuolar myopathies, neurodegenerative diseases, liver disease, and some forms of cancer. This chapter provides an overview of the morphology and molecular basis of autophagosome formation and offers a glimpse into the role of autophagy in normal growth and development, while discussing the pathological implications of its deregulation.
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Affiliation(s)
- Ameeta Kelekar
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA.
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42
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Payne CM, Holubec H, Bernstein C, Bernstein H, Dvorak K, Green SB, Wilson M, Dall'Agnol M, Dvorakova B, Warneke J, Garewal H. Crypt-restricted loss and decreased protein expression of cytochrome C oxidase subunit I as potential hypothesis-driven biomarkers of colon cancer risk. Cancer Epidemiol Biomarkers Prev 2005; 14:2066-75. [PMID: 16172211 DOI: 10.1158/1055-9965.epi-05-0180] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
There is an increasing demand for the development of intermediate biomarkers to assess colon cancer risk. We previously determined that a live cell bioassay, which assesses apoptosis resistance in the nonneoplastic colonic mucosa, detects approximately 50% of patients with colon cancer. A hypothesis-driven biomarker that reflects apoptosis resistance in routine formalin-fixed, paraffin-embedded tissue would be easier to use. Cytochrome c oxidase is a critical enzyme that controls mitochondrial respiration and is central to apoptosis. We did an immunohistochemical study of cytochrome c oxidase subunit I expression in 46 colonic mucosal samples from 16 patients who had undergone a colonic resection. These included five patients without evidence of colonic neoplasia (three normal and two diverticulitis), three patients with tubulovillous adenomas, and eight patients with colonic adenocarcinomas. Analysis of aberrancies in expression of cytochrome c oxidase subunit I showed that, compared with nonneoplasia, the patients with neoplasia had a higher mean incidence of crypts having decreased expression (1.7 versus 22.8, P = 0.03) and a higher mean incidence having crypt-restricted loss (0.6 versus 3.2, P = 0.06). The percentage with segmented loss was low and was similar in the two groups. Combining these results, the mean % normal (i.e., with none of the three types of abnormality) was 96.7 in nonneoplasia versus only 73.2 in patients with neoplasia (P = 0.02). It should be noted that a defect in cytochrome c oxidase subunit I immunostaining was not detected in all biopsy samples from each patient for whom some abnormality was found, indicating a "patchiness" in the cytochrome c oxidase subunit I field defect. As a result of this "patchiness," the increased variability in the incidence of crypt-restricted loss of cytochrome c oxidase subunit I expression was a statistically significant feature of the neoplasia group. Crypt-restricted loss of cytochrome c oxidase subunit I has not been previously reported in colonic mucosa and is presumably the result of a crypt-restricted stem cell mutation. Decreased cytochrome c oxidase subunit I expression also significantly correlated with apoptosis resistance, a factor known to contribute to carcinogenesis. The results suggest, however, that aberrant cytochrome c oxidase subunit I expression may be a better biomarker than loss of apoptosis competence for increased colon cancer risk.
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Affiliation(s)
- Claire M Payne
- Department of Cell Biology and Anatomy, College of Medicine, University of Arizona, Tucson, 85724.
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Curry BD, Govindaraju SR, Bain JLW, Zhang LL, Yan JG, Matloub HS, Riley DA. Evidence for frequency-dependent arterial damage in vibrated rat tails. ACTA ACUST UNITED AC 2005; 284:511-21. [PMID: 15791580 DOI: 10.1002/ar.a.20186] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The effects of single 4-hr bouts of continuous 30, 60, 120, and 800 Hz tail vibration (49 m/sec2, root mean squared) were compared to assess frequency-amplitude-related structural damage of the ventral caudal artery. Amplitudes were 3.9, 0.98, 0.24, and 0.0055 mm, respectively. Vibrated, sham-vibrated, and normal arteries were processed for light and electron microscopy. The Curry rat tail model of hand-arm vibration (Curry et al. Muscle Nerve 2002;25:527-534) proved well-suited for testing multiple frequencies. NFATc3 immunostaining, an early marker of cell damage, increased in smooth muscle and endothelial cells after 30, 60, and 120 Hz but not 800 Hz. Increased vacuolization, which is indicative of smooth muscle contraction, occurred for all frequencies except 800 Hz. Vacuoles increased in both endothelial and smooth muscle cells after 60 and 120 Hz. Only 30 Hz showed pronounced smooth muscle cell vacuolization along the internal and external elastic membranes, suggesting stretch-mediated contraction from the large amplitude shear stress. Discontinuities in toluidine blue staining of the internal elastic membrane (IEM) increased for all frequencies, indicating vibration-induced structural weakening of this structure. Patches of missing IEM and overlying endothelium occurred in approximately 5% of arteries after 60, 120, and 800 Hz. The pattern of damage after 800 Hz suggests that the IEM is disrupted because it resonates at this frequency. Vibration acceleration stress and smooth muscle contraction appear to be the major contributors to arterial damage. The pattern of vibration-induced arterial damage of smooth muscle and endothelial cells is frequency-amplitude-dependent.
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Affiliation(s)
- Brian D Curry
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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Lum JJ, DeBerardinis RJ, Thompson CB. Autophagy in metazoans: cell survival in the land of plenty. Nat Rev Mol Cell Biol 2005; 6:439-48. [PMID: 15928708 DOI: 10.1038/nrm1660] [Citation(s) in RCA: 599] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cells require a constant supply of macromolecular precursors and oxidizable substrates to maintain viability. Unicellular eukaryotes lack the ability to regulate nutrient concentrations in their extracellular environment. So when environmental nutrients are depleted, these organisms catabolize existing cytoplasmic components to support ATP production to maintain survival, a process known as autophagy. By contrast, the environment of metazoans normally contains abundant extracellular nutrients, but a cell's ability to take up these nutrients is controlled by growth factor signal transduction. Despite evolving the ability to maintain a constant supply of extracellular nutrients, metazoans have retained a complete set of autophagy genes. The physiological relevance of autophagy in such species is just beginning to be explored.
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Affiliation(s)
- Julian J Lum
- Abramson Family Cancer Research Institute, Department of Cancer Biology, University of Pennsylvania School of Medicine, Philadelphia, Philadelphia 19104, USA
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Nixon RA, Wegiel J, Kumar A, Yu WH, Peterhoff C, Cataldo A, Cuervo AM. Extensive involvement of autophagy in Alzheimer disease: an immuno-electron microscopy study. J Neuropathol Exp Neurol 2005; 64:113-22. [PMID: 15751225 DOI: 10.1093/jnen/64.2.113] [Citation(s) in RCA: 1115] [Impact Index Per Article: 58.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The accumulation of lysosomes and their hydrolases within neurons is a well-established neuropathologic feature of Alzheimer disease (AD). Here we show that lysosomal pathology in AD brain involves extensive alterations of macroautophagy, an inducible pathway for the turnover of intracellular constituents, including organelles. Using immunogold labeling with compartmental markers and electron microscopy on neocortical biopsies from AD brain, we unequivocally identified autophagosomes and other prelysosomal autophagic vacuoles (AVs), which were morphologically and biochemically similar to AVs highly purified from mouse liver. AVs were uncommon in brains devoid of AD pathology but were abundant in AD brains particularly, within neuritic processes, including synaptic terminals. In dystrophic neurites, autophagosomes, multivesicular bodies, multilamellar bodies, and cathepsin-containing autophagolysosomes were the predominant organelles and accumulated in large numbers. These compartments were distinguishable from lysosomes and lysosomal dense bodies, previously shown also to be abundant in dystrophic neurites. Autophagy was evident in the perikarya of affected neurons, particularly in those with neurofibrillary pathology where it was associated with a relative depletion of mitochondria and other organelles. These observations provide the first evidence that macroautophagy is extensively involved in the neurodegenerative/regenerative process in AD. The striking accumulations of immature AV forms in dystrophic neurites suggest that the transport of AVs and their maturation to lysosomes may be impaired, thereby impeding the suspected neuroprotective functions of autophagy.
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Affiliation(s)
- Ralph A Nixon
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, New York University School of Medicine, Orangeburg, New York 10962, USA.
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Castino R, Davies J, Beaucourt S, Isidoro C, Murphy D. Autophagy is a prosurvival mechanism in cells expressing an autosomal dominant familial neurohypophyseal diabetes insipidus mutant vasopressin transgene. FASEB J 2005; 19:1021-3. [PMID: 15781609 DOI: 10.1096/fj.04-3162fje] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI) is a progressive, inherited neurodegenerative disorder that presents as polydipsia and polyuria as a consequence of a loss of secretion of the antidiuretic hormone vasopressin (VP) from posterior pituitary nerve terminals. VP gene mutations cause adFNDI. Rats expressing an adFNDI VP transgene (Cys67stop) show a neuronal pathology characterized by autophagic structures in the cell body. adFNDI has thus been added to the list of protein aggregation diseases, along with Alzheimer's, Parkinson's and Huntington's, which are associated with autophagy, a bulk process that delivers regions of cytosol to lysosomes for degradation. However, the role of autophagy in these diseases is unclear. To address the relationships between mutant protein accumulation, autophagy, cell survival, and cell death, we have developed a novel and tractable in vitro system. We have constructed adenoviral vectors (Ads) that express structural genes encoding either the Cys67stop mutant protein (Ad-VCAT-Cys67stop) or an epitope-tagged wild-type VP precursor (Ad-VCAT). After infection of mouse neuroblastoma Neuro2a cells, Ad-VCAT encoded material enters neurite processes and accumulates in terminals, while the Cys67stop protein is confined to enlarged vesicles in the cell body. Similar to the intracellular derangements seen in the Cys67stop rats, these structures are of ER origin, and colocalize with markers of autophagy. Neither Ad-VCAT-Cys67stop nor Ad-VCAT expression affected cell viability. However, inhibition of autophagy or lysosomal protein degradation, while having no effect on Ad-VCAT-expressing cells, significantly increased apoptotic cell death following Ad-VCAT-Cys67stop expression. These data suggest that activation of autophagy by the stress of the expression of an adFNDI mutant protein is a prosurvival mechanism.
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Affiliation(s)
- Roberta Castino
- Molecular Neuroendocrinology Research Group, Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, England, UK
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47
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Seay M, Dinesh-Kumar S, Levine B. Digesting Oneself and Digesting Microbes. MODULATION OF HOST GENE EXPRESSION AND INNATE IMMUNITY BY VIRUSES 2005. [PMCID: PMC7121853 DOI: 10.1007/1-4020-3242-0_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
Although research in this area is still in a stage of infancy, it seems likely that the lysosomal degradation pathway of autophagy plays an evolutionarily conserved role in antiviral immunity. The interferon-inducible, antiviral PKR signaling pathway positively regulates autophagy, and both mammalian and plant autophagy genes restrict viral replication and protect against virus-induced cell death. Given this role of autophagy in innate immunity, it is not surprising that viruses have evolved numerous strategies to inhibit host autophagy. Different viral gene products can either modulate autophagy regulatory signals or directly interact with components of the autophagy execution machinery. Moreover, certain RNA viruses have managed to “co-apt” the autophagy pathway, selectively utilizing certain components of the dynamic membrane rearrangement system to promote their own replication inside the host cytoplasm. In addition to this newly emerging role of autophagy in innate immunity, autophagy plays an important role in many other fundamental biological processes, including tissue homeostasis, differentiation and development, cell growth control, and the prevention of aging. Accordingly, the inhibition of host autophagy by viral gene products has important implications not only for understanding mechanisms of immune evasion, but also for understanding novel mechanisms of viral pathogenesis. It will be interesting to dissect the role of viral inhibition of autophagy in acute, persistent, and latent viral replication, as well as in the pathogenesis of cancer and other medical diseases.
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48
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Bergamini E, Cavallini G, Donati A, Gori Z. The role of macroautophagy in the ageing process, anti-ageing intervention and age-associated diseases. Int J Biochem Cell Biol 2004; 36:2392-404. [PMID: 15325580 DOI: 10.1016/j.biocel.2004.05.007] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Macroautophagy is a degradation/recycling system ubiquitous in eukariotic cells, which generates nutrients during fasting under the control of amino acids and hormones, and contributes to the turnover and rejuvenation of cellular components (long-lived proteins, cytomembranes and organelles). Tight coupling between these two functions may be the weak point in cell housekeeping. Ageing denotes a post-maturational deterioration of tissues and organs with the passage of time, due to the progressive accumulation of the misfunctioning cell components because of oxidative damage and an age-dependent decline of turnover rate and housekeeping. Caloric restriction (CR) and lower insulin levels may slow down many age-dependent processes and extend lifespan. Recent evidence is reviewed showing that autophagy is involved in ageing and in the anti-ageing action of anti-ageing calorie restriction: function of autophagy declines during adulthood and is almost negligible at older age; CR prevents the age-dependent decline of autophagic proteolysis and improves the sensitivity of liver cells to stimulation of lysosomal degradation; protection of autophagic proteolysis from the age-related decline co-varies with the duration and level of anti-ageing food restriction like the effects of CR extending lifespan; the pharmacological stimulation of macroautophagy has anti-ageing effects. Besides the involvement in ageing, macroautophagy may have an essential role in the pathogenesis of many age-associated diseases. Higher protein turnover may not fully account for the anti-ageing effects of macroautophagy, and effects of macroautophagy on housekeeping of the cell organelles, antioxidant machinery of cell membranes and transmembrane cell signaling should also be considered.
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Affiliation(s)
- E Bergamini
- Centro di Ricerca di Biologia e Patologia dell'Invecchiamento, University of Pisa, Scuola Medica, via Roma 55, 56126 Pisa, Italy.
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Yu WH, Kumar A, Peterhoff C, Shapiro Kulnane L, Uchiyama Y, Lamb BT, Cuervo AM, Nixon RA. Autophagic vacuoles are enriched in amyloid precursor protein-secretase activities: implications for β-amyloid peptide over-production and localization in Alzheimer’s disease. Int J Biochem Cell Biol 2004; 36:2531-40. [PMID: 15325590 DOI: 10.1016/j.biocel.2004.05.010] [Citation(s) in RCA: 212] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2004] [Revised: 05/20/2004] [Accepted: 05/21/2004] [Indexed: 10/26/2022]
Abstract
In Alzheimer's disease (AD), the neuropathologic hallmarks of beta-amyloid deposition and neurofibrillary degeneration are associated with early and progressive pathology of the endosomal-lysosomal system. Abnormalities of autophagy, a major pathway to lysosomes for protein and organelle turnover, include marked accumulations of autophagy-related vesicular compartments (autophagic vacuoles or AVs) in affected neurons. Here, we investigated the possibility that AVs contain the proteases and substrates necessary to cleave the amyloid precursor protein (APP) to A beta peptide that forms beta-amyloid, a key pathogenic factor in AD. AVs were highly purified using a well-established metrizamide gradient procedure from livers of transgenic YAC mice overexpressing wild-type human APP. By Western blot analysis, AVs contained APP, beta CTF - the beta-cleaved carboxyl-terminal domain of APP, and BACE, the protease-mediating beta-cleavage of APP. beta-Secretase activity measured against a fluorogenic peptide was significantly enriched in the AV fraction relative to whole-liver lysate. Compared to other recovered subcellular fractions, AVs exhibited the highest specific activity of gamma-secretase based on a fluorogenic assay and inhibition by a specific inhibitor of gamma-secretase, DAPT. AVs were also the most enriched subcellular fraction in levels of the gamma-secretase components presenilin and nicastrin. Immunoelectron microscopy demonstrated selective immunogold labeling of AVs with antibodies specific for the carboxyl termini of human A beta 40 and A beta 42. These data indicate that AVs are a previously unrecognized and potentially highly active compartment for A beta generation and suggest that the abnormal accumulation of AVs in affected neurons of the AD brain contributes to beta-amyloid deposition.
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Affiliation(s)
- W H Yu
- Center for Dementia Research, Nathan S. Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA
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Castino R, Démoz M, Isidoro C. Destination 'lysosome': a target organelle for tumour cell killing? J Mol Recognit 2004; 16:337-48. [PMID: 14523947 DOI: 10.1002/jmr.643] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Lysosomes and lysosome-related organelles constitute a system of acid compartments that interconnect the inside of the cell with the extracellular environment via endocytosis, phagocytosis and exocytosis. In recent decades it has been recognized that lysosomes are not just wastebaskets for disposal of unused cellular constituents, but that they are involved in several cellular processes such as post-translational maturation of proteins, degradation of receptors and extracellular release of active enzymes. By complementing the autophagic process, lysosomes actively contribute to the maintenance of cellular homeostasis. Proteolysis by lysosomal cathepsins has been shown to mediate the death signal of cytotoxic drugs and cytokines, as well as the activation of pro-survival factors. Secreted lysosomal cathepsins have been shown to degrade protein components of the extracellular matrix, thus contributing actively to its re-modelling in physiological and pathological processes. The malfunction of lysosomes can, therefore, impact on cell behaviour and fate. Here we review the role of lysosomal hydrolases in several aspects of the malignant phenotype including loss of cell growth control, altered regulation of cell death, acquisition of chemoresistance and of metastatic potential. Based on these observations, the lysosome is proposed as a potential target organelle for the chemotherapy of tumours. We will also present some recent data concerning the technologies for delivering chemotherapeutic drugs to the endosomal-lysosomal compartment and the strategies to improve their efficacy.
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Affiliation(s)
- Roberta Castino
- Dipartimento di Scienze Mediche, Università degli Studi del Piemonte Orientale 'A Avogadro', Novara, Italy
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