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Armeli F, Mengoni B, Laskin DL, Businaro R. Interplay among Oxidative Stress, Autophagy, and the Endocannabinoid System in Neurodegenerative Diseases: Role of the Nrf2- p62/SQSTM1 Pathway and Nutraceutical Activation. Curr Issues Mol Biol 2024; 46:6868-6884. [PMID: 39057052 PMCID: PMC11276139 DOI: 10.3390/cimb46070410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/27/2024] [Accepted: 06/29/2024] [Indexed: 07/28/2024] Open
Abstract
The onset of neurodegenerative diseases involves a complex interplay of pathological mechanisms, including protein aggregation, oxidative stress, and impaired autophagy. This review focuses on the intricate connection between oxidative stress and autophagy in neurodegenerative disorders, highlighting autophagy as pivotal in disease pathogenesis. Reactive oxygen species (ROS) play dual roles in cellular homeostasis and autophagy regulation, with disruptions of redox signaling contributing to neurodegeneration. The activation of the Nrf2 pathway represents a critical antioxidant mechanism, while autophagy maintains cellular homeostasis by degrading altered cell components. The interaction among p62/SQSTM1, Nrf2, and Keap1 forms a regulatory pathway essential for cellular stress response, whose dysregulation leads to impaired autophagy and aggregate accumulation. Targeting the Nrf2-p62/SQSTM1 pathway holds promise for therapeutic intervention, mitigating oxidative stress and preserving cellular functions. Additionally, this review explores the potential synergy between the endocannabinoid system and Nrf2 signaling for neuroprotection. Further research is needed to elucidate the involved molecular mechanisms and develop effective therapeutic strategies against neurodegeneration.
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Affiliation(s)
- Federica Armeli
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica, 79, 04100 Latina, Italy; (F.A.); (B.M.)
| | - Beatrice Mengoni
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica, 79, 04100 Latina, Italy; (F.A.); (B.M.)
| | - Debra L. Laskin
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854, USA;
| | - Rita Businaro
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica, 79, 04100 Latina, Italy; (F.A.); (B.M.)
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Guo S, Zhang S. The Cysteine Protease CfAtg4 Interacts with CfAtg8 to Govern the Growth, Autophagy and Pathogenicity of Colletotrichum fructicola. J Fungi (Basel) 2024; 10:431. [PMID: 38921417 PMCID: PMC11204552 DOI: 10.3390/jof10060431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Revised: 06/07/2024] [Accepted: 06/08/2024] [Indexed: 06/27/2024] Open
Abstract
Camellia oleifera is a native woody oil plant in southern China and is infected with anthracnose wherever it is grown. We previously identified Colletotrichum fructicola as the major causal agent of anthracnose on C. oleifera and found that CfAtg8 regulates the pathogenicity and development of C. fructicola. Here, we revealed that CfAtg4 interacts with CfAtg8, contributing to the formation of autophagosomes. The CfAtg81-160 allele, which only contains 1-160 amino acids of the CfAtg8, partially recovered the autophagosome numbers and autophagy defects of the ΔCfatg4 mutant. Consequently, these recoveries resulted in the restoration of the defects of the ΔCfatg4 mutant in growth and responses to different external stresses, albeit to an extent. Importantly, we illustrated the critical roles of CfAtg81-160 in appressoria formation, and pathogenicity. Collectively, our findings provide new insights into the importance of the interaction between CfAtg8 and CfAtg4 in the growth, autophagy and pathogenicity of the phytopathogenic fungi.
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Affiliation(s)
- Shufeng Guo
- College of Forestry, Central South University of Forestry and Technology, Changsha 410004, China;
- Key Laboratory of Forest Bio-Resources and Integrated Pest Management for Higher Education in Hunan Province, Changsha 410004, China
- Hunan Provincial Key Laboratory for Control of Forest Diseases and Pests, Changsha 410004, China
| | - Shengpei Zhang
- College of Forestry, Central South University of Forestry and Technology, Changsha 410004, China;
- Key Laboratory of Forest Bio-Resources and Integrated Pest Management for Higher Education in Hunan Province, Changsha 410004, China
- Hunan Provincial Key Laboratory for Control of Forest Diseases and Pests, Changsha 410004, China
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3
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Gu M, Liu Y, Xin P, Guo W, Zhao Z, Yang X, Ma R, Jiao T, Zheng W. Fundamental insights and molecular interactions in pancreatic cancer: Pathways to therapeutic approaches. Cancer Lett 2024; 588:216738. [PMID: 38401887 DOI: 10.1016/j.canlet.2024.216738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 02/08/2024] [Accepted: 02/18/2024] [Indexed: 02/26/2024]
Abstract
The gastrointestinal tract can be affected by a number of diseases that pancreatic cancer (PC) is a malignant manifestation of them. The prognosis of PC patients is unfavorable and because of their diagnosis at advanced stage, the treatment of this tumor is problematic. Owing to low survival rate, there is much interest towards understanding the molecular profile of PC in an attempt in developing more effective therapeutics. The conventional therapeutics for PC include surgery, chemotherapy and radiotherapy as well as emerging immunotherapy. However, PC is still incurable and more effort should be performed. The molecular landscape of PC is an underlying factor involved in increase in progression of tumor cells. In the presence review, the newest advances in understanding the molecular and biological events in PC are discussed. The dysregulation of molecular pathways including AMPK, MAPK, STAT3, Wnt/β-catenin and non-coding RNA transcripts has been suggested as a factor in development of tumorigenesis in PC. Moreover, cell death mechanisms such as apoptosis, autophagy, ferroptosis and necroptosis demonstrate abnormal levels. The EMT and glycolysis in PC cells enhance to ensure their metastasis and proliferation. Furthermore, such abnormal changes have been used to develop corresponding pharmacological and nanotechnological therapeutics for PC.
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Affiliation(s)
- Ming Gu
- Department of Breast Surgery, The First Hospital of China Medical University, Shenyang, Liaoning, 110001, China
| | - Yang Liu
- Department of Urology, The First Hospital of China Medical University, Shenyang, Liaoning, 110001, China
| | - Peng Xin
- Department of Urology, The First Hospital of China Medical University, Shenyang, Liaoning, 110001, China
| | - Wei Guo
- Department of Pancreatic-Biliary Surgery, The First Hospital of China Medical University, Shenyang, Liaoning, 110001, China
| | - Zimo Zhao
- Department of Pancreatic-Biliary Surgery, The First Hospital of China Medical University, Shenyang, Liaoning, 110001, China
| | - Xu Yang
- Department of Pancreatic-Biliary Surgery, The First Hospital of China Medical University, Shenyang, Liaoning, 110001, China
| | - Ruiyang Ma
- Department of Otorhinolaryngology, The First Hospital of China Medical University, Shenyang, Liaoning, 110001, China.
| | - Taiwei Jiao
- Department of Gastroenterology and Endoscopy, The First Hospital of China Medical University, Shenyang, Liaoning, 110001, China.
| | - Wenhui Zheng
- Department of Anesthesiology, The Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110001, China.
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Zhang L, Liu W, Wu N, Wang H, Zhang Z, Liu Y, Wang X. Southern rice black-streaked dwarf virus induces incomplete autophagy for persistence in gut epithelial cells of its vector insect. PLoS Pathog 2023; 19:e1011134. [PMID: 36706154 PMCID: PMC9907856 DOI: 10.1371/journal.ppat.1011134] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 02/08/2023] [Accepted: 01/18/2023] [Indexed: 01/28/2023] Open
Abstract
Autophagy plays an important role in virus infection of the host, because viral components and particles can be degraded by the host's autophagy and some viruses may be able to hijack and subvert autophagy for its benefit. However, details on the mechanisms that govern autophagy for immunity against viral infections or benefit viral survival remain largely unknown. Plant reoviruses such as southern rice black-streaked dwarf virus (SRBSDV), which seriously threaten crop yield, are only transmitted by vector insects. Here, we report a novel mechanism by which SRBSDV induces incomplete autophagy by blocking autophagosome-lysosome fusion, resulting in viral accumulation in gut epithelial cells of its vector, white-backed planthopper (Sogatella furcifera). SRBSDV infection leads to stimulation of the c-Jun N-terminal kinase (JNK) signaling pathway, which further activates autophagy. Mature and assembling virions were found close to the edge7 of the outer membrane of autophagosomes. Inhibition autophagy leads to the decrease of autophagosomes, which resulting in impaired maturation of virions and the decrease of virus titer, whereas activation of autophagy facilitated virus titer. Further, SRBSDV inhibited fusion of autophagosomes and lysosomes by interacting with lysosomal-associated membrane protein 1 (LAMP1) using viral P10. Thus, SRBSDV not only avoids being degrading by lysosomes, but also further hijacks these non-fusing autophagosomes for its subsistence. Our findings reveal a novel mechanism of reovirus persistence, which can explain why SRBSDV can be acquired and transmitted rapidly by its insect vector.
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Affiliation(s)
- Lu Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Maize Research Institute, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Wenwen Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- * E-mail: (WL); (XW)
| | - Nan Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hui Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhongkai Zhang
- Biotechnology and Germplasm Resources Institute, Yunnan Key Laboratory of Agricultural Biotechnology, Yunnan Academy of Agricultural Sciences, Kunming, China
| | - Yule Liu
- MOE Key Laboratory of Bioinformatics and Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xifeng Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- * E-mail: (WL); (XW)
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Ilic D, Magnussen HM, Tirard M. Stress - Regulation of SUMO conjugation and of other Ubiquitin-Like Modifiers. Semin Cell Dev Biol 2022; 132:38-50. [PMID: 34996712 DOI: 10.1016/j.semcdb.2021.12.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 12/14/2022]
Abstract
Stress is unavoidable and essential to cellular and organismal evolution and failure to adapt or restore homeostasis can lead to severe diseases or even death. At the cellular level, stress drives a plethora of molecular changes, of which variations in the profile of protein post-translational modifications plays a key role in mediating the adaptative response of the genome and proteome to stress. In this context, post-translational modification of proteins by ubiquitin-like modifiers, (Ubl), notably SUMO, is an essential stress response mechanism. In this review, aiming to draw universal concepts of the Ubls stress response, we will decipher how stress alters the expression level, activity, specificity and/or localization of the proteins involved in the conjugation pathways of the various type-I Ubls, and how this result in the modification of particular Ubl targets that will translate an adaptive physiological stress response and allow cells to restore homeostasis.
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Affiliation(s)
- Dragana Ilic
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, D-79108 Freiburg; Faculty of Biology, University of Freiburg, D-79104 Freiburg; Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, D-37075 Göttingen
| | - Helge M Magnussen
- MRC Protein Phosphorylation and Ubiquitination Unit, Sir James Black Center, School of Life Sciences, University of Dundee, Dundee, Scotland, UK
| | - Marilyn Tirard
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, D-37075 Göttingen.
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Scorletti E, Carr RM. A new perspective on NAFLD: Focusing on lipid droplets. J Hepatol 2022; 76:934-945. [PMID: 34793866 DOI: 10.1016/j.jhep.2021.11.009] [Citation(s) in RCA: 142] [Impact Index Per Article: 71.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 10/13/2021] [Accepted: 11/06/2021] [Indexed: 02/07/2023]
Abstract
Lipid droplets (LDs) are complex and metabolically active organelles. They are composed of a neutral lipid core surrounded by a monolayer of phospholipids and proteins. LD accumulation in hepatocytes is the distinctive characteristic of non-alcoholic fatty liver disease (NAFLD), which is a chronic, heterogeneous liver condition that can progress to liver fibrosis and hepatocellular carcinoma. Though recent research has improved our understanding of the mechanisms linking LD accumulation to NAFLD progression, numerous aspects of LD biology are either poorly understood or unknown. In this review, we provide a description of several key mechanisms that contribute to LD accumulation in hepatocytes, favouring NAFLD progression. First, we highlight the importance of LD architecture and describe how the dysregulation of LD biogenesis leads to endoplasmic reticulum stress and inflammation. This is followed by an analysis of the causal nexus that exists between LD proteome composition and LD degradation. Finally, we describe how the increase in size of LDs causes activation of hepatic stellate cells, leading to liver fibrosis and hepatocellular carcinoma. We conclude that acquiring a more sophisticated understanding of LD biology will provide crucial insights into the heterogeneity of NAFLD and assist in the development of therapeutic approaches for this liver disease.
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Affiliation(s)
- Eleonora Scorletti
- Division of Translational Medicine and Human Genetics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Rotonya M Carr
- Division of Gastroenterology, University of Washington, Seattle, WA 98195-6424, United States.
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Chemotherapy Resistance: Role of Mitochondrial and Autophagic Components. Cancers (Basel) 2022; 14:cancers14061462. [PMID: 35326612 PMCID: PMC8945922 DOI: 10.3390/cancers14061462] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/10/2022] [Accepted: 03/10/2022] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Chemotherapy resistance is a common occurrence during cancer treatment that cancer researchers are attempting to understand and overcome. Mitochondria are a crucial intracellular signaling core that are becoming important determinants of numerous aspects of cancer genesis and progression, such as metabolic reprogramming, metastatic capability, and chemotherapeutic resistance. Mitophagy, or selective autophagy of mitochondria, can influence both the efficacy of tumor chemotherapy and the degree of drug resistance. Regardless of the fact that mitochondria are well-known for coordinating ATP synthesis from cellular respiration in cellular bioenergetics, little is known its mitophagy regulation in chemoresistance. Recent advancements in mitochondrial research, mitophagy regulatory mechanisms, and their implications for our understanding of chemotherapy resistance are discussed in this review. Abstract Cancer chemotherapy resistance is one of the most critical obstacles in cancer therapy. One of the well-known mechanisms of chemotherapy resistance is the change in the mitochondrial death pathways which occur when cells are under stressful situations, such as chemotherapy. Mitophagy, or mitochondrial selective autophagy, is critical for cell quality control because it can efficiently break down, remove, and recycle defective or damaged mitochondria. As cancer cells use mitophagy to rapidly sweep away damaged mitochondria in order to mediate their own drug resistance, it influences the efficacy of tumor chemotherapy as well as the degree of drug resistance. Yet despite the importance of mitochondria and mitophagy in chemotherapy resistance, little is known about the precise mechanisms involved. As a consequence, identifying potential therapeutic targets by analyzing the signal pathways that govern mitophagy has become a vital research goal. In this paper, we review recent advances in mitochondrial research, mitophagy control mechanisms, and their implications for our understanding of chemotherapy resistance.
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Li R, Zhao L, Li S, Chen F, Qiu J, Bai L, Chen B. The Autophagy-Related Gene CpAtg4 Is Required for Fungal Phenotypic Traits, Stress Tolerance, and Virulence in Cryphonectria parasitica. PHYTOPATHOLOGY 2022; 112:299-307. [PMID: 34033505 DOI: 10.1094/phyto-01-21-0015-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Autophagy is an evolutionarily ancient process wherein cells are able to break down intracellular contents to support normal physiology and development. Autophagosome formation is regulated by several different proteins, including the key cysteine protease Atg4. The contribution of Atg4 protein in the pathogenic fungus Cryphonectria parasitica, which causes blight in chestnut plants, has not been completely understood. In this context, we aimed to investigate the role of Atg4 during autophagy formation and their contribution to nonautophagic events in C. parasitica. By complementation assay, we determined that the CpAtg4 gene from C. parasitica was able to functionally complement the deletion of yeast Atg4. Using a yeast two-hybrid assay system, we confirmed that CpAtg4 and CpAtg8 directly interact with one another, and amino acids 377 to 409 of CpAtg4 were identified as being responsible for its binding with CpAtg8. The deletion mutant of CpAtg4 did not demonstrate positive monodansylcadaverine staining, which indicated that CpAtg4 is required for autophagy in C. parasitica. Moreover, the ΔCpAtg4 strain exhibited a decrease in aerial hyphae formation and sporulation, and reduction in virulence on apple and chestnut stem. The ΔCpAtg4 strains were also more sensitive to H2O2 and Congo red-induced stress. We further determined that amino acids 377 to 409 of CpAtg4 were essential for the function of CpAtg4 in vivo. Together, our findings indicated that CpAtg4 is required for the autophagy formation, fungal phenotypic traits, stress tolerance, and virulence in C. parasitica.
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Affiliation(s)
- Ru Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
| | - Lijiu Zhao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
| | - Shuangcai Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
| | - Fengyue Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
| | - Jinfeng Qiu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
| | - Lingyun Bai
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
| | - Baoshan Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, People's Republic of China
- College of Agriculture, Guangxi University, Nanning 530004, People's Republic of China
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Benvenuto M, Albonici L, Focaccetti C, Ciuffa S, Fazi S, Cifaldi L, Miele MT, De Maio F, Tresoldi I, Manzari V, Modesti A, Masuelli L, Bei R. Polyphenol-Mediated Autophagy in Cancer: Evidence of In Vitro and In Vivo Studies. Int J Mol Sci 2020; 21:E6635. [PMID: 32927836 PMCID: PMC7555128 DOI: 10.3390/ijms21186635] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 02/06/2023] Open
Abstract
One of the hallmarks of cellular transformation is the altered mechanism of cell death. There are three main types of cell death, characterized by different morphological and biochemical features, namely apoptosis (type I), autophagic cell death (type II) and necrosis (type III). Autophagy, or self-eating, is a tightly regulated process involved in stress responses, and it is a lysosomal degradation process. The role of autophagy in cancer is controversial and has been associated with both the induction and the inhibition of tumor growth. Autophagy can exert tumor suppression through the degradation of oncogenic proteins, suppression of inflammation, chronic tissue damage and ultimately by preventing mutations and genetic instability. On the other hand, tumor cells activate autophagy for survival in cellular stress conditions. Thus, autophagy modulation could represent a promising therapeutic strategy for cancer. Several studies have shown that polyphenols, natural compounds found in foods and beverages of plant origin, can efficiently modulate autophagy in several types of cancer. In this review, we summarize the current knowledge on the effects of polyphenols on autophagy, highlighting the conceptual benefits or drawbacks and subtle cell-specific effects of polyphenols for envisioning future therapies employing polyphenols as chemoadjuvants.
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Affiliation(s)
- Monica Benvenuto
- Saint Camillus International University of Health and Medical Sciences, Via di Sant’Alessandro 8, 00131 Rome, Italy;
- Department of Clinical Sciences and Translational Medicine, University of Rome “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy; (L.A.); (C.F.); (S.C.); (L.C.); (F.D.M.); (I.T.); (V.M.); (A.M.)
| | - Loredana Albonici
- Department of Clinical Sciences and Translational Medicine, University of Rome “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy; (L.A.); (C.F.); (S.C.); (L.C.); (F.D.M.); (I.T.); (V.M.); (A.M.)
| | - Chiara Focaccetti
- Department of Clinical Sciences and Translational Medicine, University of Rome “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy; (L.A.); (C.F.); (S.C.); (L.C.); (F.D.M.); (I.T.); (V.M.); (A.M.)
- Department of Human Science and Promotion of the Quality of Life, San Raffaele University Rome, Via di Val Cannuta 247, 00166 Rome, Italy
| | - Sara Ciuffa
- Department of Clinical Sciences and Translational Medicine, University of Rome “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy; (L.A.); (C.F.); (S.C.); (L.C.); (F.D.M.); (I.T.); (V.M.); (A.M.)
| | - Sara Fazi
- Department of Experimental Medicine, University of Rome “Sapienza”, Viale Regina Elena 324, 00161 Rome, Italy; (S.F.); (L.M.)
| | - Loredana Cifaldi
- Department of Clinical Sciences and Translational Medicine, University of Rome “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy; (L.A.); (C.F.); (S.C.); (L.C.); (F.D.M.); (I.T.); (V.M.); (A.M.)
- Academic Department of Pediatrics (DPUO), Ospedale Pediatrico Bambino Gesù, IRCCS, Piazza Sant’Onofrio 4, 00165 Rome, Italy
| | - Martino Tony Miele
- Department of Experimental Medicine, University of Rome “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy;
| | - Fernando De Maio
- Department of Clinical Sciences and Translational Medicine, University of Rome “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy; (L.A.); (C.F.); (S.C.); (L.C.); (F.D.M.); (I.T.); (V.M.); (A.M.)
| | - Ilaria Tresoldi
- Department of Clinical Sciences and Translational Medicine, University of Rome “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy; (L.A.); (C.F.); (S.C.); (L.C.); (F.D.M.); (I.T.); (V.M.); (A.M.)
| | - Vittorio Manzari
- Department of Clinical Sciences and Translational Medicine, University of Rome “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy; (L.A.); (C.F.); (S.C.); (L.C.); (F.D.M.); (I.T.); (V.M.); (A.M.)
| | - Andrea Modesti
- Department of Clinical Sciences and Translational Medicine, University of Rome “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy; (L.A.); (C.F.); (S.C.); (L.C.); (F.D.M.); (I.T.); (V.M.); (A.M.)
| | - Laura Masuelli
- Department of Experimental Medicine, University of Rome “Sapienza”, Viale Regina Elena 324, 00161 Rome, Italy; (S.F.); (L.M.)
| | - Roberto Bei
- Department of Clinical Sciences and Translational Medicine, University of Rome “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy; (L.A.); (C.F.); (S.C.); (L.C.); (F.D.M.); (I.T.); (V.M.); (A.M.)
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López-Pérez Ó, Badiola JJ, Bolea R, Ferrer I, Llorens F, Martín-Burriel I. An Update on Autophagy in Prion Diseases. Front Bioeng Biotechnol 2020; 8:975. [PMID: 32984276 PMCID: PMC7481332 DOI: 10.3389/fbioe.2020.00975] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/27/2020] [Indexed: 12/18/2022] Open
Abstract
Autophagy is a dynamic intracellular mechanism involved in protein and organelle turnover through lysosomal degradation. When properly regulated, autophagy supports normal cellular and developmental processes, whereas defects in autophagic degradation have been associated with several pathologies, including prion diseases. Prion diseases, or transmissible spongiform encephalopathies (TSE), are a group of fatal neurodegenerative disorders characterized by the accumulation of the pathological misfolded isoform (PrPSc) of the physiological cellular prion protein (PrPc) in the central nervous system. Autophagic vacuoles have been described in experimental models of TSE and in the natural disease in humans. The precise connection of this process with prion-related neuropathology, or even whether autophagy is completely beneficial or pathogenic during neurodegeneration, is poorly understood. Thus, the biological role of autophagy in these diseases is still open to debate. During the last years, researchers have used a wide range of morphological, genetic and biochemical methods to monitor and manipulate the autophagic pathway and thus determine the specific role of this process in TSE. It has been suggested that PrPc could play a crucial role in modulating the autophagic pathway in neuronal cells, and the presence of abnormal autophagic activity has been frequently observed in several models of TSE both in vitro and in vivo, as well as in human prion diseases. Altogether, these findings suggest that autophagy is implicated in prion neuropathology and points to an impairment or failure of the process, potentially contributing to the pathogenesis of the disease. Additionally, autophagy is now emerging as a host defense response in controlling prion infection that plays a protective role by facilitating the clearance of aggregation-prone proteins accumulated within neurons. Since autophagy is one of the pathways of PrPSc degradation, and drug-induced stimulation of autophagic flux (the dynamic process of autophagic degradation activity) produces anti-prion effects, new treatments based on its activation have been tested to develop therapeutic strategies for prion diseases. In this review, we summarize previous and recent findings concerning the role of autophagy in TSE.
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Affiliation(s)
- Óscar López-Pérez
- Laboratorio de Genética Bioquímica (LAGENBIO), Instituto Agroalimentario de Aragón-IA2, Instituto de Investigación Sanitaria Aragón-IISA, Universidad de Zaragoza, Zaragoza, Spain.,Centro de Encefalopatías y Enfermedades Transmisibles Emergentes (CEETE), Instituto Agroalimentario de Aragón-IA2, Instituto de Investigación Sanitaria Aragón-IISA, Universidad de Zaragoza, Zaragoza, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto Carlos III, L'Hospitalet de Llobregat, Barcelona, Spain.,Instituto de Investigación Biomédica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Juan José Badiola
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes (CEETE), Instituto Agroalimentario de Aragón-IA2, Instituto de Investigación Sanitaria Aragón-IISA, Universidad de Zaragoza, Zaragoza, Spain
| | - Rosa Bolea
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes (CEETE), Instituto Agroalimentario de Aragón-IA2, Instituto de Investigación Sanitaria Aragón-IISA, Universidad de Zaragoza, Zaragoza, Spain
| | - Isidro Ferrer
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto Carlos III, L'Hospitalet de Llobregat, Barcelona, Spain.,Instituto de Investigación Biomédica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain.,Departamento de Patología y Terapéutica Experimental, Universidad de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Franc Llorens
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto Carlos III, L'Hospitalet de Llobregat, Barcelona, Spain.,Instituto de Investigación Biomédica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain.,Department of Neurology, Clinical Dementia Center and National Reference Center for CJD Surveillance, University Medical School, Göttingen, Germany
| | - Inmaculada Martín-Burriel
- Laboratorio de Genética Bioquímica (LAGENBIO), Instituto Agroalimentario de Aragón-IA2, Instituto de Investigación Sanitaria Aragón-IISA, Universidad de Zaragoza, Zaragoza, Spain.,Centro de Encefalopatías y Enfermedades Transmisibles Emergentes (CEETE), Instituto Agroalimentario de Aragón-IA2, Instituto de Investigación Sanitaria Aragón-IISA, Universidad de Zaragoza, Zaragoza, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto Carlos III, Zaragoza, Spain
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11
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Long S, Ren D, Zhong F, Niu Y, Qin X, Mu D, Liu W. Reversal of glucocorticoid resistance in Acute Lymphoblastic Leukemia cells by miR-145. PeerJ 2020; 8:e9337. [PMID: 32587801 PMCID: PMC7304417 DOI: 10.7717/peerj.9337] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 05/20/2020] [Indexed: 12/16/2022] Open
Abstract
Objective To analyze the expression levels of miR-145 in ALL children and their effects on the prognosis of ALL and to explore the mechanism of miR-145 in reversing the resistance of ALL cells to glucocorticoids. Methods A GEO database dataset was used to analyze the expression levels of miR-145 in ALL children. The association between miR-145 and childhood prognosis was analyzed by the TARGET database data. The expression levels of miR-145 in the glucocorticoid-resistant ALL cell line CEM-C1 were increased by lipofectamine 2000-mediated transfection. Cell proliferation inhibition experiments were performed to detect the effect of miR-145 on the response of CEM-C1 cell line to glucocorticoids. The expression levels of the apoptotic, autophagic and drug resistance-associated genes and proteins were detected by qPCR and western blot analysis. Results The expression levels of miR-145 were decreased in ALL patients (P < 0.001) and the prognosis of ALL in children with high miR-145 expression was significantly improved (P < 0.001). Increased miR-145 expression can improve the sensitivity of CEM-C1 cells to glucocorticoids. The expression levels of the proapoptotic and the anti-apoptotic genes Bax and Bcl-2 were increased and decreased, respectively, whereas the expression levels of the autophagicgenes Beclin 1 and LC were increased. In addition, the expression levels of the drug resistance gene MDR1 were decreased. Conclusion The expression levels of miR-145 in ALL children were decreased and they were associated with disease prognosis. The data indicated that miR-145 can reverse cell resistance by regulating apoptosis of CEM-C1 cells and autophagy.
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Affiliation(s)
- Sili Long
- Department of Pediatrics, Affiliated Hospital of Southwest Medical University, Children's Blood and Tumor PI laboratory, Birth Defects Clinical Medical Research Center of Sichuan Province, Luzhou, China
| | - Danwei Ren
- Department of Pediatrics, Affiliated Hospital of Southwest Medical University, Children's Blood and Tumor PI laboratory, Birth Defects Clinical Medical Research Center of Sichuan Province, Luzhou, China
| | - Fangfang Zhong
- Department of Pediatrics, Affiliated Hospital of Southwest Medical University, Children's Blood and Tumor PI laboratory, Birth Defects Clinical Medical Research Center of Sichuan Province, Luzhou, China
| | - Yana Niu
- Department of Pediatrics, Affiliated Hospital of Southwest Medical University, Children's Blood and Tumor PI laboratory, Birth Defects Clinical Medical Research Center of Sichuan Province, Luzhou, China
| | - Xiang Qin
- Department of Pediatrics, Affiliated Hospital of Southwest Medical University, Children's Blood and Tumor PI laboratory, Birth Defects Clinical Medical Research Center of Sichuan Province, Luzhou, China
| | - Dan Mu
- Department of Pediatrics, Affiliated Hospital of Southwest Medical University, Children's Blood and Tumor PI laboratory, Birth Defects Clinical Medical Research Center of Sichuan Province, Luzhou, China
| | - Wenjun Liu
- Department of Pediatrics, Affiliated Hospital of Southwest Medical University, Children's Blood and Tumor PI laboratory, Birth Defects Clinical Medical Research Center of Sichuan Province, Luzhou, China
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12
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Autophagy Dysfunction in Alzheimer's Disease: Mechanistic Insights and New Therapeutic Opportunities. Biol Psychiatry 2020; 87:797-807. [PMID: 31262433 DOI: 10.1016/j.biopsych.2019.05.008] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 04/24/2019] [Accepted: 05/11/2019] [Indexed: 01/05/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive memory loss due to aberrant accumulation of misfolded proteins inside and outside neurons and glial cells, leading to a loss of cellular protein homeostasis. Today, no therapy is available to block or slow down AD progression, and the mechanisms of the disease are not fully understood. Autophagy is an intracellular degradation pathway crucial to maintaining cellular homeostasis by clearing damaged organelles, pathogens, and unwanted protein aggregates. In recent years, autophagy dysfunction has gained considerable attention in AD and other neurodegenerative diseases because it has been linked to the accumulation of misfolded proteins that ultimately causes neuronal death in many of these disorders. Interestingly, autophagy-activating compounds have also shown some promising results in both clinical trials and preclinical studies. This review aims at summarizing the current knowledge on autophagy dysfunction in the context of AD pathophysiology, providing recent mechanistic insights on AD-mediated autophagic flux disruption and highlighting potential and novel therapeutic opportunities that target this system for AD therapy.
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13
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Association between autophagy and rapid eye movement sleep loss-associated neurodegenerative and patho-physio-behavioral changes. Sleep Med 2019; 63:29-37. [DOI: 10.1016/j.sleep.2019.04.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 03/26/2019] [Accepted: 04/24/2019] [Indexed: 12/13/2022]
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14
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Shin JH, Park SJ, Jo DS, Park NY, Kim JB, Bae JE, Jo YK, Hwang JJ, Lee JA, Jo DG, Kim JC, Jung YK, Koh JY, Cho DH. Down-regulated TMED10 in Alzheimer disease induces autophagy via ATG4B activation. Autophagy 2019; 15:1495-1505. [PMID: 30821607 DOI: 10.1080/15548627.2019.1586249] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Several studies have shown that dysfunction of macroautophagy/autophagy is associated with many human diseases, including neurodegenerative disease and cancer. To explore the molecular mechanisms of autophagy, we performed a cell-based functional screening with SH-SY5Y cells stably expressing GFP-LC3, using an siRNA library and identified TMED10 (transmembrane p24 trafficking protein 10), previously known as the γ-secretase-modulating protein, as a novel regulator of autophagy. Further investigations revealed that depletion of TMED10 induced the activation of autophagy. Interestingly, protein-protein interaction assays showed that TMED10 directly binds to ATG4B (autophagy related gene 4B cysteine peptidase), and the interaction is diminished under autophagy activation conditions such as rapamycin treatment and serum deprivation. In addition, inhibition of TMED10 significantly enhanced the proteolytic activity of ATG4B for LC3 cleavage. Importantly, the expression of TMED10 in AD (Alzheimer disease) patients was considerably decreased, and downregulation of TMED10 increased amyloid-β (Aβ) production. Treatment with Aβ increased ATG4B proteolytic activity as well as dissociation of TMED10 and ATG4B. Taken together, our results suggest that the AD-associated protein TMED10 negatively regulates autophagy by inhibiting ATG4B activity.Abbreviations: Aβ: amyloid-β; AD: Alzheimer disease; ATG: autophagy related; BECN1: beclin 1; BiFC: bimolecular fluorescence complementation; CD: cytosolic domain; GFP: green fluorescent protein; GLUC: Gaussia luciferase; IP: immunoprecipitation; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; LD: luminal domain; PD: Parkinson disease; ROS: reactive oxygen species; siRNA: small interfering RNA; SNP: single-nucleotide polymorphisms; TD: transmembrane domain; TMED10: transmembrane p24 trafficking protein 10; VC: C terminus of Venus fluorescent protein; VN: N terminus of Venus fluorescent protein.
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Affiliation(s)
- Ji Hyun Shin
- a School of Life Sciences, Kyungpook National University , Daegu , Republic of Korea.,b Department of Gerontology, Graduate School of E-W Medical Science, Kyung Hee University , Yongin , South Korea
| | - So Jung Park
- b Department of Gerontology, Graduate School of E-W Medical Science, Kyung Hee University , Yongin , South Korea
| | - Doo Sin Jo
- a School of Life Sciences, Kyungpook National University , Daegu , Republic of Korea
| | - Na Yeon Park
- a School of Life Sciences, Kyungpook National University , Daegu , Republic of Korea
| | - Joon Bum Kim
- a School of Life Sciences, Kyungpook National University , Daegu , Republic of Korea
| | - Ji-Eun Bae
- a School of Life Sciences, Kyungpook National University , Daegu , Republic of Korea.,b Department of Gerontology, Graduate School of E-W Medical Science, Kyung Hee University , Yongin , South Korea
| | - Yoon Kyung Jo
- b Department of Gerontology, Graduate School of E-W Medical Science, Kyung Hee University , Yongin , South Korea
| | - Jung Jin Hwang
- c Asan Institute for Life Sciences, Asan Medical Center , Seoul , South Korea
| | - Jin-A Lee
- d College of Life Sciences and Nanotechnology, Hannam University , Daejeon , South Korea
| | - Dong-Gyu Jo
- e School of Pharmacy, Sungkyunkwan University , Suwon , South Korea
| | - Jin Cheon Kim
- f Department of Surgery, University of Ulsan College of Medicine, Asan Medical Center , Seoul , South Korea
| | - Yong Keun Jung
- g School of Biological Sciences, Seoul National University , Seoul , South Korea
| | - Jae-Young Koh
- h Department of Neurology, University of Ulsan College of Medicine, Asan Medical Center , Seoul , South Korea
| | - Dong-Hyung Cho
- a School of Life Sciences, Kyungpook National University , Daegu , Republic of Korea
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15
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Cho SJ, Lim HJ, Jo C, Park MH, Han C, Koh YH. Plasma ATG5 is increased in Alzheimer's disease. Sci Rep 2019; 9:4741. [PMID: 30894637 PMCID: PMC6427023 DOI: 10.1038/s41598-019-41347-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 03/07/2019] [Indexed: 02/06/2023] Open
Abstract
Alzheimer’s disease (AD) is a major cause of dementia. Growing evidence suggests that dysregulation of autophagy, a cellular mechanism essential for self-digestion of damaged proteins and organelles, is involved in neurological degenerative diseases including AD. Previously, we reported that autophagosomes are increased in the brains of AD mouse model. However, the plasma levels of autophagic markers have not yet been investigated in patients with AD. In this study, we investigated the expression of autophagy-related genes 5 and 12 (ATG5 and ATG12, respectively) in cells in vitro upon amyloid-beta (Aβ) treatment and in the plasma of AD patients. ATG5-ATG12 complex levels were increased in primary rat cortical neurons and human umbilical vein endothelial cells after Aβ treatment. Furthermore, we compared plasma from 69 patients with dementia, 82 patients with mild cognitive impairment (MCI), and 127 cognitively normal control participants. Plasma levels of ATG5 were significantly elevated in patients with dementia (149.3 ± 7.5 ng/mL) or MCI (152.9 ± 6.9 ng/mL) compared with the control subjects (129.0 ± 4.1 ng/mL) (p = 0.034, p = 0.016, respectively). Our results indicate that alterations in the plasma ATG5 levels might be a potential biomarker in patients at risk for AD.
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Affiliation(s)
- Sun-Jung Cho
- Division of Brain Diseases, Center for Biomedical Sciences, Korea National Institute of Health, 187 Osongsaengmyeong2-ro, Osong-eup, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do, 28159, Korea
| | - Hyun Joung Lim
- Division of Brain Diseases, Center for Biomedical Sciences, Korea National Institute of Health, 187 Osongsaengmyeong2-ro, Osong-eup, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do, 28159, Korea
| | - Chulman Jo
- Division of Brain Diseases, Center for Biomedical Sciences, Korea National Institute of Health, 187 Osongsaengmyeong2-ro, Osong-eup, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do, 28159, Korea
| | - Moon Ho Park
- Departments of Neurology, Korea University, Ansan Hospital, 123 Jeokgeum-ro, Danwon-gu, Ansan-si, Gyeonggi-do, 15355, Korea
| | - Changsu Han
- Psychiatry, College of Medicine, Korea University, Ansan Hospital, 123 Jeokgeum-ro, Danwon-gu, Ansan-si, Gyeonggi-do, 15355, Korea
| | - Young Ho Koh
- Division of Brain Diseases, Center for Biomedical Sciences, Korea National Institute of Health, 187 Osongsaengmyeong2-ro, Osong-eup, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do, 28159, Korea.
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16
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Di Fazio P, Matrood S. Targeting autophagy in liver cancer. Transl Gastroenterol Hepatol 2018; 3:39. [PMID: 30148224 PMCID: PMC6088143 DOI: 10.21037/tgh.2018.06.09] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 06/27/2018] [Indexed: 02/05/2023] Open
Abstract
Autophagy is a catabolic cellular process conserved in animals. It is characterized by the main role of recycling all the non-functional products of the cells. Once, autophagy players detect non-functioning sub-cellular organelles and proteins, they start the so-called nucleation process. The organelles will be surrounded by a double membrane vesicle mainly constituted by endoplasmic reticulum (ER) membrane and autophagy proteins, e.g., MAP1LC3B, Beclin-1, VPS34, Unc-51 like autophagy activating kinase (ULK1) and ubiquitination-related proteins. Then the autophagic membrane will go through an elongation phase involving additional autophagy players. Once the autophagic vesicle is complete, the sub-cellular organelles will be isolated from the rest of the cytosol and driven to the final fusion with lysosomes. Here, the digestion process will end. Alteration and or impairment of autophagy have been shown to be correlated with development of diseases affecting the central nervous system, e.g., Alzheimer and other neurodegenerative diseases. Nonetheless, autophagy defect is responsible for tumorigenesis in blood and solid malignancies, in particular liver cancer. Malignancies of the liver are determined by several genetics and epigenetics mechanisms triggering the up-regulation of survival mechanisms and resistance to cell death. Furthermore, liver cancer could result from pathologic conditions like cirrhosis and fibrosis related to virus infection, aflatoxin, alcohol consumption and high fat diet together with insulin resistance. The role exerted by autophagy in the pathogenesis of the liver and tumor development has been evidenced in recent years. The alteration of autophagy assumes a fundamental role for liver tumorigenesis determining an accumulation of non-functional proteins and organelles that trigger oxidative stress leading to genotoxic stress and gene alterations. Furthermore, the absence of this degradation mechanism could prompt the cells to alter their metabolic status and turn into malignant cells. Interestingly, the heterozygous loss of function of Beclin-1 is able to trigger liver tumorigenesis or even the simple accumulation of proteins caused by the block of the final autolysosome fusion and degradation process is responsible for liver cancer development. This review highlights the importance of targeting the autophagy process in liver cancer in order to restore its function and to promote autophagy-mediated cell demise.
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Affiliation(s)
- Pietro Di Fazio
- Department of Visceral Thoracic and Vascular Surgery, Philipps University Marburg, Baldingerstrasse, Marburg, Germany
| | - Sami Matrood
- Department of Visceral Thoracic and Vascular Surgery, Philipps University Marburg, Baldingerstrasse, Marburg, Germany
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17
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Wang P, Sun X, Jia X, Ma F. Apple autophagy-related protein MdATG3s afford tolerance to multiple abiotic stresses. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2017; 256:53-64. [PMID: 28167039 DOI: 10.1016/j.plantsci.2016.12.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 11/28/2016] [Accepted: 12/08/2016] [Indexed: 05/02/2023]
Abstract
The efficient degradation system of autophagy in plant cells has important roles in removing and recycling intracellular components during normal development or under environmental stresses. Formation of autophagosomes requires the conjugation of ubiquitin-like protein ATG8 to phosphatidylethanolamine (PE). We isolated two ubiquitin-conjugating enzyme E2-like ATG3 homologues from Malus domestica - MdATG3a and MdATG3b - that are crucial for ATG8-PE conjugation. Both share a conserved N-terminal, as well as the catalytic and C-terminal domains of ATG3 with HPC and FLKF motifs. Each promoter was isolated from genomic DNA and contained several cis-acting elements that are involved in responses to environmental stresses or hormones. In addition to having the same cellular localization in the nucleus and cytoplasm, MdATG3a and MdATG3b showed similar expression patterns toward leaf senescence, nitrogen starvation, drought, salinity, and oxidative stress at the transcriptional level. Ectopic expression of either in Arabidopsis conferred tolerance to osmotic or salinity stress and also improved growth performance under nitrogen- or carbon-starvation. Callus lines of 'Orin' apple that over-expressed MdATG3b also displayed better growth performance when nutrient supplies were limited. These overall results demonstrate that, as important autophagy genes, overexpression of MdATG3s can afford tolerance to multiple abiotic stresses at the cellular and whole-plant level.
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Affiliation(s)
- Ping Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xun Sun
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xin Jia
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Fengwang Ma
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China.
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18
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Li R, Guo E, Yang J, Li A, Yang Y, Liu S, Liu A, Jiang X. 1,25(OH) 2 D 3 attenuates hepatic steatosis by inducing autophagy in mice. Obesity (Silver Spring) 2017; 25:561-571. [PMID: 28145056 DOI: 10.1002/oby.21757] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 11/22/2016] [Accepted: 12/03/2016] [Indexed: 01/10/2023]
Abstract
OBJECTIVE 1,25(OH)2 D3 has been reported to attenuate liver steatosis; however, its exact mechanism of action remains poorly understood. This study aimed to determine whether 1,25(OH)2 D3 can attenuate hepatic steatosis by inducing autophagy. METHODS Male C57BL/6 mice fed a high-fat diet (HFD) were injected with 1,25(OH)2 D3 for 4 weeks. These mice were given 3-methyladenine (3-MA) to inhibit autophagy. HepG2 cells were preincubated with a free fatty acid (FFA) and then treated with 1,25(OH)2 D3 . Vitamin D receptor (VDR) shRNA and autophagy-related 16-like 1 (ATG16L1) siRNA were used for VDR knockdown or ATG16L1 silencing, respectively. RESULTS 1,25(OH)2 D3 diminished HFD-induced liver damage and steatosis, changes accompanied by autophagy and ATG16L1 expression upregulation. Inhibition of 1,25(OH)2 D3 -induced autophagy mediated by 3-MA blocked the protective effects of 1,25(OH)2 D3 on hepatic steatosis. Additionally, 1,25(OH)2 D3 -induced autophagy appeared to play a role in anti-inflammation and lipid metabolism modulation in the liver. In HepG2 cells, 1,25(OH)2 D3 reduced lipid accumulation and increased autophagy and ATG16L1 expression; however, this effect was abrogated after VDR knockdown. The protective effects of 1,25(OH)2 D3 -mediated autophagy against lipid accumulation were abolished by 3-MA. Furthermore, siRNA-mediated ATG16L1 knockdown prevented 1,25(OH)2 D3 -induced autophagy, resulting in increased fat accumulation. CONCLUSIONS The data suggest that 1,25(OH)2 D3 may ameliorate hepatic steatosis by inducing autophagy by upregulating ATG16L1.
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Affiliation(s)
- Renlong Li
- Graduate School, Southern Medical University, Guangzhou, China
- Department of Infectious Diseases, Wuhan General Hospital of Guangzhou Military Command, Wuhan, China
| | - Enshuang Guo
- Graduate School, Southern Medical University, Guangzhou, China
- Department of Infectious Diseases, Wuhan General Hospital of Guangzhou Military Command, Wuhan, China
| | - Jiankun Yang
- Experimental Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Anyi Li
- Animal Experimental Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yan Yang
- Experimental Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shenpei Liu
- Experimental Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Anding Liu
- Experimental Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaojing Jiang
- Graduate School, Southern Medical University, Guangzhou, China
- Department of Infectious Diseases, Wuhan General Hospital of Guangzhou Military Command, Wuhan, China
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19
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Landajuela A, Hervás JH, Antón Z, Montes LR, Gil D, Valle M, Rodriguez JF, Goñi FM, Alonso A. Lipid Geometry and Bilayer Curvature Modulate LC3/GABARAP-Mediated Model Autophagosomal Elongation. Biophys J 2016; 110:411-422. [PMID: 26789764 DOI: 10.1016/j.bpj.2015.11.3524] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/14/2015] [Accepted: 11/30/2015] [Indexed: 11/29/2022] Open
Abstract
Autophagy, an important catabolic pathway involved in a broad spectrum of human diseases, implies the formation of double-membrane-bound structures called autophagosomes (AP), which engulf material to be degraded in lytic compartments. How APs form, especially how the membrane expands and eventually closes upon itself, is an area of intense research. Ubiquitin-like ATG8 has been related to both membrane expansion and membrane fusion, but the underlying molecular mechanisms are poorly understood. Here, we used two minimal reconstituted systems (enzymatic and chemical conjugation) to compare the ability of human ATG8 homologs (LC3, GABARAP, and GATE-16) to mediate membrane fusion. We found that both enzymatically and chemically lipidated forms of GATE-16 and GABARAP proteins promote extensive membrane tethering and fusion, whereas lipidated LC3 does so to a much lesser extent. Moreover, we characterize the GATE-16/GABARAP-mediated membrane fusion as a phenomenon of full membrane fusion, independently demonstrating vesicle aggregation, intervesicular lipid mixing, and intervesicular mixing of aqueous content, in the absence of vesicular content leakage. Multiple fusion events give rise to large vesicles, as seen by cryo-electron microscopy observations. We also show that both vesicle diameter and selected curvature-inducing lipids (cardiolipin, diacylglycerol, and lyso-phosphatidylcholine) can modulate the fusion process, smaller vesicle diameters and negative intrinsic curvature lipids (cardiolipin, diacylglycerol) facilitating fusion. These results strongly support the hypothesis of a highly bent structural fusion intermediate (stalk) during AP biogenesis and add to the growing body of evidence that identifies lipids as important regulators of autophagy.
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Affiliation(s)
- Ane Landajuela
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Javier H Hervás
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Zuriñe Antón
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - L Ruth Montes
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - David Gil
- Structural Biology Unit, Center for Cooperative Research in Biosciences, CIC bioGUNE, Derio, Spain
| | - Mikel Valle
- Structural Biology Unit, Center for Cooperative Research in Biosciences, CIC bioGUNE, Derio, Spain
| | - J Francisco Rodriguez
- Departmento de Biología Molecular y Celular, Centro Nacional de Biotecnología-CSIC, Cantoblanco, Madrid, Spain
| | - Felix M Goñi
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Alicia Alonso
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain.
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20
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Li W, Yang Y, Hou X, Zhuang H, Wu Z, Li Z, Guo R, Chen H, Lin C, Zhong W, Chen Y, Wu K, Zhang L, Feng D. MicroRNA-495 regulates starvation-induced autophagy by targeting ATG3. FEBS Lett 2016; 590:726-38. [PMID: 26910393 DOI: 10.1002/1873-3468.12108] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 01/31/2016] [Accepted: 02/08/2016] [Indexed: 12/21/2022]
Abstract
The functions of some essential autophagy genes are regulated by microRNAs. However, an ATG3-modulating microRNA has never been reported. Here we show that the transcription of miR-495 negatively correlates with the translation of ATG3 under nutrient-deprived or rapamycin-treated conditions. miR-495 targets ATG3 and regulates its protein levels under starvation conditions. miR-495 also inhibits starvation-induced autophagy by decreasing the number of autophagosomes and by preventing LC3-I-to-LC3-II transition and P62 degradation. These processes are reversed by the overexpression of an endogenous miR-495 inhibitor. Re-expression of Atg3 without miR-495 response elements restores miR-495-inhibited autophagy. miR-495 sustains cell viability under starvation conditions but has no effect under hypoxia. Moreover, miR-495 inhibits etoposide-induced cell death. In conclusion, miR-495 is involved in starvation-induced autophagy by regulating Atg3.
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Affiliation(s)
- Wen Li
- Guangdong Key Laboratory of Age-related Cardiac-cerebral Vascular Disease, Institute of Neurology, Affiliated Hospital of Guangdong Medical College, Zhanjiang, China
| | - Yue Yang
- Department of Anesthesiology, Guangdong Medical College, Zhanjiang, China
| | - Xiaoyan Hou
- Guangdong Key Laboratory of Age-related Cardiac-cerebral Vascular Disease, Institute of Neurology, Affiliated Hospital of Guangdong Medical College, Zhanjiang, China
| | - Haixia Zhuang
- Department of Anesthesiology, Guangdong Medical College, Zhanjiang, China
| | - Zijun Wu
- Department of Cardiovasology, the Affiliated Hospital of Guangdong Medical College, Zhanjiang, China
| | - Zhiyi Li
- Department of Anesthesiology, Guangdong Medical College, Zhanjiang, China
| | - Runmin Guo
- Department of Cardiovasology, the Affiliated Hospital of Guangdong Medical College, Zhanjiang, China
| | - Hao Chen
- Guangdong Key Laboratory of Age-related Cardiac-cerebral Vascular Disease, Institute of Neurology, Affiliated Hospital of Guangdong Medical College, Zhanjiang, China
| | - Chunxia Lin
- Guangdong Key Laboratory of Age-related Cardiac-cerebral Vascular Disease, Institute of Neurology, Affiliated Hospital of Guangdong Medical College, Zhanjiang, China
| | - Wangtao Zhong
- Guangdong Key Laboratory of Age-related Cardiac-cerebral Vascular Disease, Institute of Neurology, Affiliated Hospital of Guangdong Medical College, Zhanjiang, China
| | - Yusen Chen
- Guangdong Key Laboratory of Age-related Cardiac-cerebral Vascular Disease, Institute of Neurology, Affiliated Hospital of Guangdong Medical College, Zhanjiang, China
| | - Keng Wu
- Department of Cardiovasology, the Affiliated Hospital of Guangdong Medical College, Zhanjiang, China
| | - Liangqing Zhang
- Department of Anesthesiology, Guangdong Medical College, Zhanjiang, China
| | - Du Feng
- Guangdong Key Laboratory of Age-related Cardiac-cerebral Vascular Disease, Institute of Neurology, Affiliated Hospital of Guangdong Medical College, Zhanjiang, China
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21
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Choi YJ, Yoo WH. Pathogenic Role of Autophagy in Rheumatic Diseases. JOURNAL OF RHEUMATIC DISEASES 2016. [DOI: 10.4078/jrd.2016.23.4.202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yun Jung Choi
- Division of Rheumatology, Department of Internal Medicine, Chonbuk National University Medical School, Jeonju, Korea
| | - Wan-Hee Yoo
- Division of Rheumatology, Department of Internal Medicine, Chonbuk National University Medical School, Jeonju, Korea
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22
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Rashid HO, Yadav RK, Kim HR, Chae HJ. ER stress: Autophagy induction, inhibition and selection. Autophagy 2015; 11:1956-1977. [PMID: 26389781 DOI: 10.1080/15548627.2015.1091141] [Citation(s) in RCA: 561] [Impact Index Per Article: 62.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
An accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) leads to stress conditions. To mitigate such circumstances, stressed cells activate a homeostatic intracellular signaling network cumulatively called the unfolded protein response (UPR), which orchestrates the recuperation of ER function. Macroautophagy (hereafter autophagy), an intracellular lysosome-mediated bulk degradation pathway for recycling and eliminating wornout proteins, protein aggregates, and damaged organelles, has also emerged as an essential protective mechanism during ER stress. These 2 systems are dynamically interconnected, and recent investigations have revealed that ER stress can either stimulate or inhibit autophagy. However, the stress-associated molecular cues that control the changeover switch between induction and inhibition of autophagy are largely obscure. This review summarizes the crosstalk between ER stress and autophagy and their signaling networks mainly in mammalian-based systems. Additionally, we highlight current knowledge on selective autophagy and its connection to ER stress.
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Affiliation(s)
- Harun-Or Rashid
- a Department of Pharmacology ; Medical School; Chonbuk National University
| | - Raj Kumar Yadav
- a Department of Pharmacology ; Medical School; Chonbuk National University
| | - Hyung-Ryong Kim
- b Department of Dental Pharmacology ; College of Dentistry; Wonkwang University
| | - Han-Jung Chae
- a Department of Pharmacology ; Medical School; Chonbuk National University
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23
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Kim JH, Hong SB, Lee JK, Han S, Roh KH, Lee KE, Kim YK, Choi EJ, Song HK. Insights into autophagosome maturation revealed by the structures of ATG5 with its interacting partners. Autophagy 2015; 11:75-87. [PMID: 25484072 DOI: 10.4161/15548627.2014.984276] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Autophagy is a bulky catabolic process that responds to nutrient homeostasis and extracellular stress signals and is a conserved mechanism in all eukaryotes. When autophagy is induced, cellular components are sequestered within an autophagosome and finally degraded by subsequent fusion with a lysosome. During this process, the ATG12-ATG5 conjugate requires 2 different binding partners, ATG16L1 for autophagosome elongation and TECPR1 for lysosomal fusion. In our current study, we describe the crystal structures of human ATG5 in complex with an N-terminal domain of ATG16L1 as well as an internal AIR domain of TECPR1. Both binding partners exhibit a similar α-helical structure containing a conserved binding motif termed AFIM. Furthermore, we characterize the critical role of the C-terminal unstructured region of the AIR domain of TECPR1. These findings are further confirmed by biochemical and cell biological analyses. These results provide new insights into the molecular details of the autophagosome maturation process, from its elongation to its fusion with a lysosome.
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Key Words
- AFIM, ATG5 (5)-interacting motif
- AIR, ATG12–ATG5-interacting region
- ATG, autophagy-related
- ATG12
- ATG16
- ATG16N69, ATG16L1 N-terminal 69 residues
- ATG5
- DAPI, 4’, 6-diamidino-2-phenylindole
- FITC, fluorescein isothiocyanate
- FLuc, firefly luciferase
- FP, fluorescent polarization
- GAL4-BD, GAL4-DNA binding domain
- GFP, green fluorescent protein
- HR, helix rich
- ITC, isothermal titration calorimetry
- MR, molecular replacement
- PE, phosphatidylethanolamine
- PH, pleckstrin homology
- PtdIns3P, phosphatidylinositol 3-phosphate
- RLuc, Renilla luciferase
- SPR, surface plasmon resonance
- TECAIR, TECPR1 AIR
- TECPR1
- TECPR1, tectonin β-propeller repeat containing 1
- UFD, ubiquitin-fold domain
- Ubl, ubiquitin-like protein
- VP16-AD, herpes simplex virus VP16 transcription activation domain
- autophagy
- buffer A, buffer containing 50 mM Tris-HCl, pH 8.0, 300 mM NaCl, and 1 mM TCEP
- crystal structure
- lysosome fusion
- r.m.s., root-mean-square
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Affiliation(s)
- Jun Hoe Kim
- a Division of Life Sciences ; Korea University ; Seoul , Korea
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24
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Liang DH, El-Zein R, Dave B. Autophagy Inhibition to Increase Radiosensitization in Breast Cancer. ACTA ACUST UNITED AC 2015; 6. [PMID: 26613064 DOI: 10.4172/2155-9619.1000254] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Currently, many breast cancer patients with localized breast cancer undergo breast-conserving therapy, consisting of local excision followed by radiation therapy. Following radiation therapy, breast cancer cells are noted to undergo induction of autophagy, development of radioresistance, and enrichment of breast cancer stem cell subpopulations. It is hypothesized that inhibition of the cytoprotective autophagy that arises following radiation therapy increases radiosensitivity and confers longer relapse-free survival by eliminating tumor-initiating breast cancer stem cells. Therefore, we reviewed the controversial role of autophagy in breast cancer tumorigenesis and progression, autophagy induction by radiotherapy, and utilization of autophagy inhibitors to increase radiosensitivity of breast cancer and to target radioresistant breast cancer stem cells.
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Affiliation(s)
- Diana Hwang Liang
- Department of Surgery, Houston Methodist Hospital, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Randa El-Zein
- Department of Radiology, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Bhuvanesh Dave
- Houston Methodist Cancer Center, Houston Methodist Research Institute, Houston, TX 77030, USA
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25
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Abstract
MicroRNAs (miRNAs) are small non-coding RNAs, 18-23 nucleotides long, which act as post-transcriptional regulators of gene expression. miRNAs are strongly implicated in the pathogenesis of many common diseases, including IBDs. This review aims to outline the history, biogenesis and regulation of miRNAs. The role of miRNAs in the development and regulation of the innate and adaptive immune system is discussed, with a particular focus on mechanisms pertinent to IBD and the potential translational applications.
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Affiliation(s)
- R Kalla
- Gastrointestinal Unit, Centre for Molecular Medicine, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, UK
| | - N T Ventham
- Gastrointestinal Unit, Centre for Molecular Medicine, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, UK
| | - N A Kennedy
- Gastrointestinal Unit, Centre for Molecular Medicine, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, UK
| | - J F Quintana
- Centre for Immunity, Infection and Evolution, Ashworth laboratories, University of Edinburgh, Edinburgh, UK
| | - E R Nimmo
- Gastrointestinal Unit, Centre for Molecular Medicine, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, UK
| | - A H Buck
- Centre for Immunity, Infection and Evolution, Ashworth laboratories, University of Edinburgh, Edinburgh, UK
| | - J Satsangi
- Gastrointestinal Unit, Centre for Molecular Medicine, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, UK
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26
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Xie T, Li SJ, Guo MR, Wu Y, Wang HY, Zhang K, Zhang X, Ouyang L, Liu J. Untangling knots between autophagic targets and candidate drugs, in cancer therapy. Cell Prolif 2015; 48:119-39. [PMID: 25650136 DOI: 10.1111/cpr.12167] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 10/05/2014] [Indexed: 02/05/2023] Open
Abstract
Autophagy is an evolutionarily conserved lysosomal mechanism implicated in a wide variety of pathological processes, such as cancer. Autophagy can be regulated by a limited number of autophagy-related genes (Atgs) such as oncogenic Bcl-2/Bcl-XL , mTORC1, Akt and PI3KCI, and tumour suppressive proteins PI3KCIII, Beclin-1, Bif-1, p53, DAPKs, PTEN and UVRAG, which play their crucial roles in regulating autophagy-related cancer. As autophagy has a dual role in cancer cells, with tumour-promoting and tumour-suppressing properties, it has become an attractive target for a series of emerging small molecule drugs. In this review, we reveal new discoveries of related small molecules or chemical compounds that can regulate autophagic pathways and lead to pro-death or pro-survival autophagy, in different types of cancer. We discuss the knots between autophagic targets and candidate drugs, in the hope of shedding new light on exploiting new anti-tumour small molecule drugs for future cancer therapy.
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Affiliation(s)
- Tao Xie
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
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27
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Selective VPS34 inhibitor blocks autophagy and uncovers a role for NCOA4 in ferritin degradation and iron homeostasis in vivo. Nat Cell Biol 2014; 16:1069-79. [PMID: 25327288 DOI: 10.1038/ncb3053] [Citation(s) in RCA: 528] [Impact Index Per Article: 52.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 09/16/2014] [Indexed: 12/17/2022]
Abstract
Cells rely on autophagy to clear misfolded proteins and damaged organelles to maintain cellular homeostasis. In this study we use the new autophagy inhibitor PIK-III to screen for autophagy substrates. PIK-III is a selective inhibitor of VPS34 that binds a unique hydrophobic pocket not present in related kinases such as PI(3)Kα. PIK-III acutely inhibits autophagy and de novo lipidation of LC3, and leads to the stabilization of autophagy substrates. By performing ubiquitin-affinity proteomics on PIK-III-treated cells we identified substrates including NCOA4, which accumulates in ATG7-deficient cells and co-localizes with autolysosomes. NCOA4 directly binds ferritin heavy chain-1 (FTH1) to target the iron-binding ferritin complex with a relative molecular mass of 450,000 to autolysosomes following starvation or iron depletion. Interestingly, Ncoa4(-/-) mice exhibit a profound accumulation of iron in splenic macrophages, which are critical for the reutilization of iron from engulfed red blood cells. Taken together, the results of this study provide a new mechanism for selective autophagy of ferritin and reveal a previously unappreciated role for autophagy and NCOA4 in the control of iron homeostasis in vivo.
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28
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Lu C, Chen J, Xu HG, Zhou X, He Q, Li YL, Jiang G, Shan Y, Xue B, Zhao RX, Wang Y, Werle KD, Cui R, Liang J, Xu ZX. MIR106B and MIR93 prevent removal of bacteria from epithelial cells by disrupting ATG16L1-mediated autophagy. Gastroenterology 2014; 146:188-99. [PMID: 24036151 PMCID: PMC3870037 DOI: 10.1053/j.gastro.2013.09.006] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 08/14/2013] [Accepted: 09/07/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Variants in genes that regulate autophagy have been associated with Crohn's disease (CD). Defects in autophagy-mediated removal of pathogenic microbes could contribute to the pathogenesis of CD. We investigated the role of the microRNAs (miRs) MIR106B and MIR93 in induction of autophagy and bacterial clearance in human cell lines and the correlation between MIR106B and autophagy-related gene 16L1 (ATG16L1) expression in tissues from patients with CD. METHODS We studied the ability of MIR106B and MIR93 to regulate ATG transcripts in human cancer cell lines (HCT116, SW480, HeLa, and U2OS) using luciferase report assays and bioinformatics analyses; MIR106B and MIR93 mimics and antagonists were transfected into cells to modify levels of miRs. Cells were infected with LF82, a CD-associated adherent-invasive strain of Escherichia coli, and monitored by confocal microscopy and for colony-forming units. Colon tissues from 41 healthy subjects (controls), 22 patients with active CD, 16 patients with inactive CD, and 7 patients with chronic inflammation were assessed for levels of MIR106B and ATG16L1 by in situ hybridization and immunohistochemistry. RESULTS Silencing Dicer1, an essential processor of miRs, increased levels of ATG protein and formation of autophagosomes in cells, indicating that miRs regulate autophagy. Luciferase reporter assays indicated that MIR106B and MIR93 targeted ATG16L1 messenger RNA. MIR106B and MIR93 reduced levels of ATG16L1 and autophagy; these increased after expression of ectopic ATG16L1. In contrast, MIR106B and MIR93 antagonists increased formation of autophagosomes. Levels of MIR106B were increased in intestinal epithelia from patients with active CD, whereas levels of ATG16L1 were reduced compared with controls. Levels of c-Myc were also increased in intestinal epithelia of patients with active CD compared with controls. These alterations could impair removal of CD-associated bacteria by autophagy. CONCLUSIONS In human cell lines, MIR106B and MIR93 reduce levels of ATG16L1 and autophagy and prevent autophagy-dependent eradication of intracellular bacteria. This process also appears to be altered in colon tissues from patients with active CD.
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Affiliation(s)
- Changming Lu
- Division of Hematology and Oncology, Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jianfeng Chen
- Division of Hematology and Oncology, Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Hua-Guo Xu
- Division of Hematology and Oncology, Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Xianzheng Zhou
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota; Departments of Pediatrics, Microbiology and Immunology, and Cell Biology and Anatomy, New York Medical College, Valhalla, New York
| | - Qiongqiong He
- Department of Pathology, Xiangya School of Medicine, Central South University, Changsha, Hunan, China
| | - Yu-Lin Li
- Key Laboratory of Pathobiology, Ministry of Education, Norman Bethune College of Medicine, Jilin University, Changchun, Jilin, China
| | - Guoqing Jiang
- Department of Surgery, 2nd Affiliated Hospital, Soochow University, Suzhou, Jiangsu, China
| | - Yuxi Shan
- Department of Surgery, 2nd Affiliated Hospital, Soochow University, Suzhou, Jiangsu, China
| | - Boxin Xue
- Department of Surgery, 2nd Affiliated Hospital, Soochow University, Suzhou, Jiangsu, China
| | - Rui-Xun Zhao
- Division of Hematology and Oncology, Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Yong Wang
- Division of Hematology and Oncology, Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Kaitlin D Werle
- Division of Hematology and Oncology, Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Rutao Cui
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts
| | - Jiyong Liang
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Zhi-Xiang Xu
- Division of Hematology and Oncology, Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama.
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29
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Jamart C, Naslain D, Gilson H, Francaux M. Higher activation of autophagy in skeletal muscle of mice during endurance exercise in the fasted state. Am J Physiol Endocrinol Metab 2013; 305:E964-74. [PMID: 23964069 DOI: 10.1152/ajpendo.00270.2013] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Activation of autophagy in skeletal muscle has been reported in response to endurance exercise and food deprivation independently. The purpose of this study was to evaluate whether autophagy was more activated when both stimuli were combined, namely when endurance exercise was performed in a fasted rather than a fed state. Mice performed a low-intensity running exercise (10 m/min for 90min) in both dietary states after which the gastrocnemius muscles were removed. LC3b-II, a marker of autophagosome presence, increased in both conditions, but the increase was higher in the fasted state. Other protein markers of autophagy, like Gabarapl1-II and Atg12 conjugated form as well as mRNA of Lc3b, Gabarapl1, and p62/Sqstm1 were increased only when exercise was performed in a fasted state. The larger activation of autophagy by exercise in a fasted state was associated with a larger decrease in plasma insulin and phosphorylation of Akt(Ser473), Akt(Thr308), FoxO3a(Thr32), and ULK1(Ser757). AMPKα(Thr172), ULK1(Ser317), and ULK1(Ser555) remained unchanged in both conditions, whereas p38(Thr180/Tyr182) increased during exercise to a similar extent in the fasted and fed conditions. The marker of mitochondrial fission DRP1(Ser616) was increased by exercise independently of the nutritional status. Changes in mitophagy markers BNIP3 and Parkin suggest that mitophagy was increased during exercise in the fasted state. In conclusion, our results highlight a major implication of the insulin-Akt-mTOR pathway and its downstream targets FoxO3a and ULK1 in the larger activation of autophagy observed when exercise is performed in a fasted state compared with a fed state.
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Affiliation(s)
- Cécile Jamart
- Institute of Neuroscience, Université catholique de Louvain, Louvain-la-Neuve, Belgium
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30
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Dai JP, Wu LQ, Li R, Zhao XF, Wan QY, Chen XX, Li WZ, Wang GF, Li KS. Identification of 23-(s)-2-amino-3-phenylpropanoyl-silybin as an antiviral agent for influenza A virus infection in vitro and in vivo. Antimicrob Agents Chemother 2013; 57:4433-43. [PMID: 23836164 PMCID: PMC3754338 DOI: 10.1128/aac.00759-13] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 06/26/2013] [Indexed: 02/05/2023] Open
Abstract
It has been reported that autophagy is involved in the replication of many viruses. In this study, we screened 89 medicinal plants, using an assay based on the inhibition of the formation of the Atg12-Atg5/Atg16 heterotrimer, an important regulator of autophagy, and selected Silybum marianum L. for further study. An antiviral assay indicated that silybin (S0), the major active compound of S. marianum L., can inhibit influenza A virus (IAV) infection. We later synthesized 5 silybin derivatives (S1 through S5) and found that 23-(S)-2-amino-3-phenylpropanoyl-silybin (S3) had the best activity. When we compared the polarities of the substituent groups, we found that the hydrophobicity of the substituent groups was positively correlated with their activities. We further studied the mechanisms of action of these compounds and determined that S0 and S3 also inhibited both the formation of the Atg12-Atg5/Atg16 heterotrimer and the elevated autophagy induced by IAV infection. In addition, we found that S0 and S3 could inhibit several components induced by IAV infection, including oxidative stress, the activation of extracellular signal-regulated kinase (ERK)/p38 mitogen-activated protein kinase (MAPK) and IκB kinase (IKK) pathways, and the expression of autophagic genes, especially Atg7 and Atg3. All of these components have been reported to be related to the formation of the Atg12-Atg5/Atg16 heterotrimer, which might validate our screening strategy. Finally, we demonstrated that S3 can significantly reduce influenza virus replication and the associated mortality in infected mice. In conclusion, we identified 23-(S)-2-amino-3-phenylpropanoyl-silybin as a promising inhibitor of IAV infection.
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Affiliation(s)
- Jian-Ping Dai
- Department of Microbiology and Immunology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Li-Qi Wu
- Department of Microbiology and Immunology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Rui Li
- Department of Microbiology and Immunology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Xiang-Feng Zhao
- Department of Microbiology and Immunology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Qian-Ying Wan
- Department of Microbiology and Immunology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Xiao-Xuan Chen
- Department of Microbiology and Immunology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Wei-Zhong Li
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
| | - Ge-Fei Wang
- Department of Microbiology and Immunology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Kang-Sheng Li
- Department of Microbiology and Immunology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
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Brigger D, Torbett BE, Chen J, Fey MF, Tschan MP. Inhibition of GATE-16 attenuates ATRA-induced neutrophil differentiation of APL cells and interferes with autophagosome formation. Biochem Biophys Res Commun 2013; 438:283-8. [PMID: 23891751 PMCID: PMC4225710 DOI: 10.1016/j.bbrc.2013.07.056] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 07/16/2013] [Indexed: 12/11/2022]
Abstract
Autophagy is an intracellular bulk degradation process involved in cell survival upon stress induction, but also with a newly identified function in myeloid differentiation. The autophagy-related (ATG)8 protein family, including the GABARAP and LC3 subfamilies, is crucial for autophagosome biogenesis. In order to evaluate the significance of the GABARAPs in the pathogenesis of acute myeloid leukemia (AML), we compared their expression in primary AML patient samples, CD34(+) progenitor cells and in granulocytes from healthy donors. GABARAPL1 and GABARAPL2/GATE-16, but not GABARAP, were significantly downregulated in particular AML subtypes compared to normal granulocytes. Moreover, the expression of GABARAPL1 and GATE-16 was significantly induced during ATRA-induced neutrophil differentiation of acute promyelocytic leukemia cells (APL). Lastly, knocking down GABARAPL2/GATE-16 in APL cells attenuated neutrophil differentiation and decreased autophagic flux. In conclusion, low GABARAPL2/GATE-16 expression is associated with an immature myeloid leukemic phenotype and these proteins are necessary for neutrophil differentiation of APL cells.
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Affiliation(s)
- Daniel Brigger
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
- Experimental Oncology/Hematology, Department of Clinical Research, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Bruce E. Torbett
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Joy Chen
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Martin F. Fey
- Experimental Oncology/Hematology, Department of Clinical Research, University of Bern, Bern, Switzerland
- Department of Medical Oncology, Inselspital, Bern University Hospital, Bern, Switzerland
| | - Mario P. Tschan
- Division of Experimental Pathology, Institute of Pathology, University of Bern, Bern, Switzerland
- Experimental Oncology/Hematology, Department of Clinical Research, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
- Department of Medical Oncology, Inselspital, Bern University Hospital, Bern, Switzerland
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Chi PI, Huang WR, Lai IH, Cheng CY, Liu HJ. The p17 nonstructural protein of avian reovirus triggers autophagy enhancing virus replication via activation of phosphatase and tensin deleted on chromosome 10 (PTEN) and AMP-activated protein kinase (AMPK), as well as dsRNA-dependent protein kinase (PKR)/eIF2α signaling pathways. J Biol Chem 2012; 288:3571-84. [PMID: 23233667 DOI: 10.1074/jbc.m112.390245] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Autophagy has been shown to facilitate replication or production of avian reovirus (ARV); nevertheless, how ARV induces autophagy remains largely unknown. Here, we demonstrate that the nonstructural protein p17 of ARV functions as an activator of autophagy. ARV-infected or p17-transfected cells present a fast and strong induction of autophagy, resulting in an increased level of autophagic proteins Beclin 1 and LC3-II. Although autophagy was suppressed by 3-methyladenine or shRNAs targeting autophagic proteins (Beclin 1, ATG7, and LC3) as well as by overexpression of Bcl-2, viral transcription, σC protein synthesis, and virus yield were all significantly reduced, suggesting a key role of autophagosomes in supporting ARV replication. Furthermore, we revealed for the first time that p17 positively regulates phosphatase and tensin deleted on chromosome 10 (PTEN), AMP-activated protein kinase (AMPK), and dsRNA dependent protein kinase RNA (PKR)/eIF2α signaling pathways, accompanied by down-regulation of Akt and mammalian target of rapamycin complex 1, thereby triggering autophagy. By using p53, PTEN, PKR, AMPK, and p17 short hairpin RNA (shRNA), activation of signaling pathways and LC3-II levels was significantly suppressed, suggesting that p17 triggers autophagy through activation of p53/PTEN, AMPK, and PKR signaling pathways. Furthermore, colocalization of LC3 with viral proteins (p17 and σC), p62 with LAMP2 and LC3 with Rab7 was observed under a fluorescence microscope. The expression level of p62 was increased at 18 h postinfection and then slightly decreased 24 h postinfection compared with mock infection and thapsigargin treatment. Furthermore, disruption of autophagosome-lysosome fusion by shRNAs targeting LAMP2 or Rab7a resulted in inhibition of viral protein synthesis and virus yield, suggesting that formation of autolysosome benefits virus replication. Taken together, our results suggest that ARV induces formation of autolysosome but does not induce complete autophagic flux.
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Affiliation(s)
- Pei I Chi
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan
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33
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Al-Zeer MA, Al-Younes HM, Lauster D, Abu Lubad M, Meyer TF. Autophagy restricts Chlamydia trachomatis growth in human macrophages via IFNG-inducible guanylate binding proteins. Autophagy 2012; 9:50-62. [PMID: 23086406 DOI: 10.4161/auto.22482] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Interferon γ (IFNG) is a key host response regulator of intracellular pathogen replication, including that of Chlamydia spp The antichlamydial functions of IFNG manifest in a strictly host, cell-type and chlamydial strain dependent manner. It has been recently shown that the IFNG-inducible family of immunity-related GTPases (IRG) proteins plays a key role in the defense against nonhost adapted chlamydia strains in murine epithelial cells. In humans, IFN-inducible guanylate binding proteins (hGBPs) have been shown to potentiate the antichlamydial effect of IFNG; however, how hGBPs regulate this property of IFNG is unknown. In this study, we identified hGBP1/2 as important resistance factors against C. trachomatis infection in IFNG-stimulated human macrophages. Exogenous IFNG reduced chlamydial infectivity by 50 percent in wild-type cells, whereas shRNA hGBP1/2 knockdown macrophages fully supported chlamydial growth in the presence of exogenous IFNG. hGBP1/2 were recruited to bacterial inclusions in human macrophages upon stimulation with IFNG, which triggered rerouting of the typically nonfusogenic bacterial inclusions for lysosomal degradation. Inhibition of lysosomal activity and autophagy impaired the IFNG-mediated elimination of inclusions. Thus, hGBP1/2 are critical effectors of antichlamydial IFNG responses in human macrophages. Through their capacity to remodel classically nonfusogenic chlamydial inclusions and stimulate fusion with autophagosomes, hGBP1/2 disable a major chlamydial virulence mechanism and contribute to IFNG-mediated pathogen clearance.
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Affiliation(s)
- Munir A Al-Zeer
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
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Zhang Y, Zeng X, Jin S. Autophagy in adipose tissue biology. Pharmacol Res 2012; 66:505-12. [PMID: 23017672 DOI: 10.1016/j.phrs.2012.09.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 09/05/2012] [Indexed: 12/25/2022]
Abstract
Obesity, which predisposes individuals to type II diabetes and cardiovascular diseases, results from accumulation of white adipose tissue (WAT). WAT comprises mainly white adipocytes that have a unique cellular structure in which almost the entire intracellular space is occupied by one single lipid droplet. The cytoplasm envelopes this lipid droplet and occupies negligible space. Differentiation of WAT, or adipogenesis, requires dramatic cytoplasmic reorganization, including a dynamic change in mitochondrial mass. Autophagy is a major cytoplasmic degradation pathway and a primary pathway for mitochondrial degradation. Recent studies indicate that autophagy is implicated in adipogenesis. In this review, we summarize our current knowledge on autophagy in adipose tissue biology, with the emphasis on its role in mitochondrial degradation. Adipose tissue is a central component for whole-body energy homeostasis regulation. Advancement in this research area may provide novel venues for the intervention of obesity and obesity related diseases.
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Affiliation(s)
- Yong Zhang
- Department of Pharmacology and the Cancer Institute of New Jersey, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
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Garcia-Garcia A, Rodriguez-Rocha H, Tseng MT, Montes de Oca-Luna R, Zhou HS, McMasters KM, Gomez-Gutierrez JG. E2F-1 lacking the transcriptional activity domain induces autophagy. Cancer Biol Ther 2012; 13:1091-101. [PMID: 22825328 DOI: 10.4161/cbt.21143] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The transcription factor E2F-1 plays a crucial role in the control of cell proliferation. E2F-1 has tumor suppressive properties by inducing apoptosis and autophagy. In this study, E2F-1 and its truncated form (E2Ftr), lacking the transactivation domain (TAD), were compared for their ability to induce autophagy. In Gaussia luciferase-based assays, both E2F-1 and E2Ftr induced the proteolytic cleavage of the autophagic marker LC3. In addition, LC3 and autophagy protein 5 (Atg5) were upregulated by E2F-1 and E2Ftr. Likewise, both E2F proteins induced a punctate pattern of GFP-tagged LC3, indicating autophagosome formation. The presence of double-membrane autophagic vesicles induced by E2F-1 and E2Ftr was confirmed by transmission electron microscopy (TEM). The application of z-VAD-fmk, a caspase inhibitor, partially blocked both E2F-1 and E2Ftr-mediated cytotoxicity. Moreover, Atg5 (-/-) cells were more resistant to the E2F-1 or E2Ftr-induced cell killing effect than Atg5 wt cells. The TAD of E2F-1 is not essential for induction of autophagy; apoptosis and autophagy cooperate for an efficient cancer cell killing effect induced by E2F-1 or E2Ftr. E2Ftr-induced autophagy is a promising approach to destroy tumors that are resistant to conventional treatments.
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36
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Autophagy can repair endoplasmic reticulum stress damage of the passive Heymann nephritis model as revealed by proteomics analysis. J Proteomics 2012; 75:3866-76. [DOI: 10.1016/j.jprot.2012.04.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 03/16/2012] [Accepted: 04/12/2012] [Indexed: 12/22/2022]
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Mijaljica D, Prescott M, Devenish RJ. The intriguing life of autophagosomes. Int J Mol Sci 2012; 13:3618-3635. [PMID: 22489171 PMCID: PMC3317731 DOI: 10.3390/ijms13033618] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 03/02/2012] [Accepted: 03/07/2012] [Indexed: 12/14/2022] Open
Abstract
Autophagosomes are double-membrane vesicles characteristic of macroautophagy, a degradative pathway for cytoplasmic material and organelles terminating in the lysosomal or vacuole compartment for mammals and yeast, respectively. This highly dynamic, multi-step process requires significant membrane reorganization events at different stages of the macroautophagic process. Such events include exchange and flow of lipids and proteins between membranes and vesicles (e.g., during initiation and growth of the phagophore), vesicular positioning and trafficking within the cell (e.g., autophagosome location and movement) and fusion of autophagosomes with the boundary membranes of the degradative compartment. Here, we review current knowledge on the contribution of different organelles to the formation of autophagosomes, their trafficking and fate within the cell. We will consider some of the unresolved questions related to the molecular mechanisms that regulate the "life and death" of the autophagosome.
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Affiliation(s)
- Dalibor Mijaljica
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton campus, Victoria 3800, Australia; E-Mails: (D.M.); (M.P.)
| | - Mark Prescott
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton campus, Victoria 3800, Australia; E-Mails: (D.M.); (M.P.)
| | - Rodney J. Devenish
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton campus, Victoria 3800, Australia; E-Mails: (D.M.); (M.P.)
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38
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Abstract
Autophagy is an intracellular lysosome-dependent catabolic process that is indispensable for maintaining cellular homeostasis through the turnover and elimination of defective or redundant proteins and damaged or aged organelles. Recent studies suggest that autophagy may be closely associated with tumorigenesis and the response of tumor cells to chemotherapeutic drugs. This article reviews recent advances in understanding the molecular mechanisms underlying the regulation of autophagy and the role of autophagy in oncogenesis and anticancer therapy. It is paradoxical that autophagy acts as a mechanism for tumor suppression and contributes to the survival of tumors. In addition, whether autophagy in response to chemotherapies results in cell death or instead protects cancer cells from death is complicated, depending on the nature of the cancer and the drug.
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Yang HJ, Hsu CL, Yang JY, Yang WY. Monodansylpentane as a blue-fluorescent lipid-droplet marker for multi-color live-cell imaging. PLoS One 2012; 7:e32693. [PMID: 22396789 PMCID: PMC3291611 DOI: 10.1371/journal.pone.0032693] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 01/29/2012] [Indexed: 01/28/2023] Open
Abstract
Lipid droplets (LDs) are dynamic cellular organelles responsible for the storage of neutral lipids, and are associated with a multitude of metabolic syndromes. Here we report monodansylpentane (MDH) as a high contrast blue-fluorescent marker for LDs. The unique spectral properties make MDH easily combinable with other green and red fluorescent reporters for multicolor fluorescence imaging. MDH staining does not apparently affect LD trafficking, and the dye is extraordinarily photo-stable. Taken together MDH represents a reliable tool to use for the investigation of dynamic LD regulation within living cells using fluorescence microscopy.
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Affiliation(s)
- Huei-Jiun Yang
- Institute of Biological Chemistry, Academia Sinica, National Taiwan University, Taipei, Taiwan
- Institute of Biochemical Sciences, College of Life Sciences, National Taiwan University, Taipei, Taiwan
| | - Chia-Ling Hsu
- Institute of Biological Chemistry, Academia Sinica, National Taiwan University, Taipei, Taiwan
| | - Jin-Yi Yang
- Institute of Biological Chemistry, Academia Sinica, National Taiwan University, Taipei, Taiwan
| | - Wei Yuan Yang
- Institute of Biological Chemistry, Academia Sinica, National Taiwan University, Taipei, Taiwan
- Institute of Biochemical Sciences, College of Life Sciences, National Taiwan University, Taipei, Taiwan
- * E-mail:
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Korkmaz G, le Sage C, Tekirdag KA, Agami R, Gozuacik D. miR-376b controls starvation and mTOR inhibition-related autophagy by targeting ATG4C and BECN1. Autophagy 2012; 8:165-76. [PMID: 22248718 DOI: 10.4161/auto.8.2.18351] [Citation(s) in RCA: 195] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Macroautophagy (autophagy) is the major intracellular degradation pathway for long-lived proteins and organelles. It helps the cell to survive a spectrum of stressful conditions including starvation, growth factor deprivation and misfolded protein accumulation. Moreover, abnormalities of autophagy play a role in major health problems including cancer and neurodegenerative diseases. Yet, mechanisms controlling autophagic activity are not fully understood. Here, we describe hsa-miR-376b (miR-376b) as a new microRNA (miRNA) regulating autophagy. We showed that miR-376b expression attenuated starvation- and rapamycin-induced autophagy in MCF-7 and Huh-7 cells. We discovered autophagy proteins ATG4C and BECN1 (Beclin 1) as cellular targets of miR-376b. Indeed, upon miRNA overexpression, both mRNA and protein levels of ATG4C and BECN1 were decreased. miR-376b target sequences were present in the 3' UTR of ATG4C and BECN1 mRNAs and introduction of mutations abolished their miR-376b responsiveness. Antagomir-mediated inactivation of the endogenous miR-376b led to an increase in ATG4C and BECN1 levels. Therefore, miR-376b controls autophagy by directly regulating intracellular levels of two key autophagy proteins, ATG4C and BECN1.
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Affiliation(s)
- Gozde Korkmaz
- Faculty of Engineering and Natural Sciences, Biological Sciences and Bioengineering Program, Sabanci University, Orhanli-Tuzla, Istanbul, Turkey
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41
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Dennissen FJA, Kholod N, van Leeuwen FW. The ubiquitin proteasome system in neurodegenerative diseases: culprit, accomplice or victim? Prog Neurobiol 2012; 96:190-207. [PMID: 22270043 DOI: 10.1016/j.pneurobio.2012.01.003] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 12/18/2011] [Accepted: 01/05/2012] [Indexed: 12/14/2022]
Abstract
A shared hallmark for many neurodegenerative disorders is the accumulation of toxic protein species which is assumed to be the cause for these diseases. Since the ubiquitin proteasome system (UPS) is the most important pathway for selective protein degradation it is likely that it is involved in the aetiology neurodegenerative disorders. Indeed, impairment of the UPS has been reported to occur during neurodegeneration. Although accumulation of toxic protein species (amyloid β) are in turn known to impair the UPS the relationship is not necessarily causal. We provide an overview of the most recent insights in the roles the UPS plays in protein degradation and other processes. Additionally, we discuss the role of the UPS in clearance of the toxic proteins known to accumulate in the hallmarks of neurodegenerative diseases. The present paper will focus on critically reviewing the involvement of the UPS in specific neurodegenerative diseases and will discuss if UPS impairment is a cause, a consequence or both of the disease.
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Affiliation(s)
- F J A Dennissen
- Department of Neuroscience, Faculty of Health Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
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42
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Shi JH, Hu DH, Zhang ZF, Bai XZ, Wang HT, Zhu XX, Su YJ, Tang CW. Reduced expression of microtubule-associated protein 1 light chain 3 in hypertrophic scars. Arch Dermatol Res 2012; 304:209-15. [PMID: 22237724 DOI: 10.1007/s00403-012-1204-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 12/22/2011] [Accepted: 01/02/2012] [Indexed: 12/19/2022]
Abstract
Autophagy is a tightly regulated physiological process essential for cellular maintenance, differentiation, development, and homeostasis. Aberration of this process associates with the pathogeneses of several diseases in mammals. Hypertrophic scar (HS) is characterized by an abundance of collagenous tissue with hypercellularity. However, the molecular mechanism in HS formation is poorly understood. We compared the autophagic capacity in HS and its normal skin (NS) counterparts and explored the molecular mechanism of autophagy during the formation of HS. Microtubule-associated protein 1 light chain 3 (LC3) proteins in HS and NS were detected by immunohistochemistry, Western blot and quantitative real-time PCR (qPCR). The data showed that LC3 positive staining in HS was less intensive relative to NS group (p < 0.05). Three forms of LC3, with molecular weights of about 19 kDa (proLC3), 18 kDa (LC3-I) and 16 kDa (LC3-II), respectively, expressed in NS by Western blot. In contrast, only proLC3 expressed while both LC3-I and LC3-II were significantly downregulated in HS. The protein level of beclin 1 in HS was significantly lower compared with NS (p < 0.05). LC3 and beclin 1 mRNA levels in HS were significantly lower than that in NS (p < 0.05). These results suggest that the generation of LC3-I and LC3-II are interrupted in HS, and that the resultant decrease of autophagic capacity may associate with the pathogenesis of HS.
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Affiliation(s)
- Ji-Hong Shi
- Department of Burns and Cutaneous Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
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Abdulrahman BA, Khweek AA, Akhter A, Caution K, Kotrange S, Abdelaziz DHA, Newland C, Rosales-Reyes R, Kopp B, McCoy K, Montione R, Schlesinger LS, Gavrilin MA, Wewers MD, Valvano MA, Amer AO. Autophagy stimulation by rapamycin suppresses lung inflammation and infection by Burkholderia cenocepacia in a model of cystic fibrosis. Autophagy 2011; 7:1359-70. [PMID: 21997369 DOI: 10.4161/auto.7.11.17660] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Cystic fibrosis (CF) is the most common inherited lethal disease of Caucasians which results in multi organ dysfunction. However, 85% of the deaths are due to pulmonary infections. Infection by Burkholderia cenocepacia (B. cepacia) is a particularly lethal threat to CF patients because it causes severe and persistent lung inflammation and is resistant to nearly all available antibiotics. In CFTR ΔF508 mouse macrophages, B. cepacia persists in vacuoles that do not fuse with the lysosomes and mediates increased production of IL-1β. It is believed that intracellular bacterial survival contributes to the persistence of the bacterium. Here we show for the first time that in wild-type macrophages but not in ΔF508 macrophages, many B. cepacia reside in autophagosomes that fuse with lysosomes at later stages of infection. Accordingly, association and intracellular survival of B. cepacia are higher in CFTR-ΔF508 (ΔF508) macrophages than in WT macrophages. An autophagosome is a compartment that engulfs non-functional organelles and parts of the cytoplasm then delivers them to the lysosome for degradation to produce nutrients during periods of starvation or stress. Furthermore, we show that B. cepacia downregulates autophagy genes in WT and ΔF508 macrophages. However, autophagy dysfunction is more pronounced in ΔF508 macrophages since they already have compromised autophagy activity. We demonstrate that the autophagy-stimulating agent, rapamycin markedly decreases B. cepacia infection in vitro by enhancing the clearance of B. cepacia via induced autophagy. In vivo, Rapamycin decreases bacterial burden in the lungs of CF mice and drastically reduces signs of lung inflammation. Together, our studies reveal that if efficiently activated, autophagy can control B. cepacia infection and ameliorate the associated inflammation. Therefore, autophagy is a novel target for new drug development for CF patients to control B. cepacia infection and accompanying inflammation.
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Affiliation(s)
- Basant A Abdulrahman
- Center for Microbial Interface Biology, Department of Microbial Infection, Ohio State University, Columbus, OH, USA
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Martyniszyn L, Szulc L, Boratyńska A, Niemiałtowski MG. Beclin 1 is involved in regulation of apoptosis and autophagy during replication of ectromelia virus in permissive L929 cells. Arch Immunol Ther Exp (Warsz) 2011; 59:463-71. [PMID: 21972018 DOI: 10.1007/s00005-011-0149-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 07/25/2011] [Indexed: 12/19/2022]
Abstract
Several reports have brought to light new and interesting findings on the involvement of autophagy and apoptosis in pathogenesis of viral and bacterial diseases, as well as presentation of foreign antigens. Our model studies focused on the involvement of apoptosis during replication of highly virulent Moscow strain of ectromelia virus (ECTV-MOS). Here, we show evidence that autophagy is induced during mousepox replication in a cell line. Fluorescence microscopy revealed increase of LC3 (microtubule-associated protein 1 light chain 3) aggregation in infected as opposed to non-infected control L929 cells. Furthermore, Western blot analysis showed that replication of ECTV-MOS in L929 cells led to the increase in LC3-II (marker of autophagic activity) expression. Beclin 1 strongly colocalized with extranuclear viral replication centers in infected cells, whereas expression of Bcl-2 decreased in those centers as shown by fluorescence microscopy. Loss of Beclin 1-Bcl-2 interaction may lead to autophagy in virus-infected L929 cells. To assess if Beclin 1 has a role in regulation of apoptosis during ECTV-MOS infection, we used small interfering RNA directed against beclin 1 following infection. Early and late apoptotic cells were analyzed by flow cytometry after AnnexinV and propidium iodide staining. Silencing of beclin 1 resulted in decreased percentage of early and late apoptotic cells in the late stage of ECTV-MOS infection in L929 cells. We conclude that Beclin 1 plays an important role in regulation of both, autophagy and apoptosis, during ECTV-MOS replication in L929 permissive cells.
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Affiliation(s)
- Lech Martyniszyn
- Division of Immunology, Department of Preclinical Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, Ciszewskiego 8, 02-786, Warsaw, Poland
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Abstract
Autophagy (macroautophagy), or the degradation of large numbers of cytoplasmic components, is induced by extracellular and intracellular signals, including oxidative stress, ceramide, and endoplasmic reticulum stress. This dynamic process involves membrane formation and fusion, including autophagosome formation, autophagosome-lysosome fusion, and the degradation of intra-autophagosomal contents by lysosomal hydrolases. Autophagy is associated with tumorigenesis, neurodegenerative diseases, cardiomyopathy, Crohn's disease, fatty liver, type II diabetes, defense against intracellular pathogens, antigen presentation, and longevity. Among the proteins and multimolecular complexes that contribute to autophagosome formation are the PI(3)-binding proteins, the PI3-phosphatases, the Rab proteins, the Atg1/ULK1 protein-kinase complex, the Atg9•Atg2-Atg18 complex, the Vps34-Atg6/beclin1 class III PI3-kinase complex, and the Atg12 and Atg8/LC3 conjugation systems. Two ubiquitin-like modifications, the Atg12 and LC3 conjugations, are essential for membrane elongation and autophagosome formation. Recent findings have revealed that processes of selective autophagy, including pexophagy, mitophagy, ERphagy (reticulophagy), and the p62-dependent degradation of ubiquitin-positive aggregates, are physiologically important in various disease states, whereas "classical" autophagy is considered nonselective degradation. Processes of selective autophagy require specific Atg proteins in addition to the "core" Atg complexes. Finally, methods to monitor autophagic activity in mammalian cells are described.
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Affiliation(s)
- Isei Tanida
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Shinjyuku, Japan.
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Abstract
Autophagy (macroautophagy) is a dynamic process for degradation of cytosolic components. Autophagy has intracellular anti-viral and anti-bacterial functions, and plays a role in the initiation of innate and adaptive immune system responses to viral and bacterial infections. Some viruses encode virulence factors for blocking autophagy, whereas others utilize some autophagy components for their intracellular growth or cellular budding. The "core" autophagy-related (Atg) complexes in mammals are ULK1 protein kinase, Atg9-WIPI-1 and Vps34-beclin1 class III PI3-kinase complexes, and the Atg12 and LC3 conjugation systems. In addition, PI(3)-binding proteins, PI3-phosphatases, and Rab proteins contribute to autophagy. The autophagy process consists of continuous dynamic membrane formation and fusion. In this review, the relationships between these Atg complexes and each process are described. Finally, the critical points for monitoring autophagy, including the use of GFP-LC3 and GFP-Atg5, are discussed.
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Affiliation(s)
- Isei Tanida
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Toyama, Shinjyuku, Tokyo, Japan.
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Itakura E, Mizushima N. Characterization of autophagosome formation site by a hierarchical analysis of mammalian Atg proteins. Autophagy 2010; 6:764-76. [PMID: 20639694 DOI: 10.4161/auto.6.6.12709] [Citation(s) in RCA: 628] [Impact Index Per Article: 44.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Autophagy is an intracellular degradation process, through which cytosolic materials are delivered to the lysosome.Despite recent identification of many autophagy-related genes, how autophagosomes are generated remains unclear.Here, we examined the hierarchical relationships among mammalian Atg proteins. Under starvation conditions, ULK1,Atg14, WIPI-1, LC3 and Atg16L1 target to the same compartment, whereas DFCP1 localizes adjacently to these Atgproteins. In terms of puncta formation, the protein complex including ULK1 and FIP200 is the most upstream unit and is required for puncta formation of the Atg14-containing PI3-kinase complex. Puncta formation of both DFCP1 and WIPI-1 requires FIP200 and Atg14. The Atg12-Atg5-Atg16L1 complex and LC3 are downstream units among these factors. The punctate structures containing upstream Atg proteins such as ULK1 and Atg14 tightly associate with the ER, where the ER protein vacuole membrane protein 1 (VMP1) also transiently localizes. These structures are formed even when cells are treated with wortmannin to suppress autophagosome formation. These hierarchical analyses suggest that ULK1, Atg14 and VMP1 localize to the ER-associated autophagosome formation sites in a PI3-kinase activity-independent manner.
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Affiliation(s)
- Eisuke Itakura
- Department of Physiology and Cell Biology, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
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48
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Abstract
Gut microbiota is an assortment of microorganisms inhabiting the length and width of the mammalian gastrointestinal tract. The composition of this microbial community is host specific, evolving throughout an individual's lifetime and susceptible to both exogenous and endogenous modifications. Recent renewed interest in the structure and function of this "organ" has illuminated its central position in health and disease. The microbiota is intimately involved in numerous aspects of normal host physiology, from nutritional status to behavior and stress response. Additionally, they can be a central or a contributing cause of many diseases, affecting both near and far organ systems. The overall balance in the composition of the gut microbial community, as well as the presence or absence of key species capable of effecting specific responses, is important in ensuring homeostasis or lack thereof at the intestinal mucosa and beyond. The mechanisms through which microbiota exerts its beneficial or detrimental influences remain largely undefined, but include elaboration of signaling molecules and recognition of bacterial epitopes by both intestinal epithelial and mucosal immune cells. The advances in modeling and analysis of gut microbiota will further our knowledge of their role in health and disease, allowing customization of existing and future therapeutic and prophylactic modalities.
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Affiliation(s)
- Inna Sekirov
- Michael Smith Laboratories, Department of Microbiology and Immunology, The University of British Columbia, Vancouver, British Columbia, Canada
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Ma JF, Huang Y, Chen SD, Halliday G. Immunohistochemical evidence for macroautophagy in neurones and endothelial cells in Alzheimer's disease. Neuropathol Appl Neurobiol 2010; 36:312-9. [DOI: 10.1111/j.1365-2990.2010.01067.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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50
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Apel A, Zentgraf H, Büchler MW, Herr I. Autophagy-A double-edged sword in oncology. Int J Cancer 2009; 125:991-5. [PMID: 19452527 DOI: 10.1002/ijc.24500] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Autophagy or "self-eating" digests proteins and functionless cell organelles to reuse. This cell-own recycling system attracts much attention in tumour biology. One of the major functions of autophagy is maintaining cellular homeostasis. Thus, it is constitutive active in all living cells. Damaged or dispensable proteins and organelles are removed to regulate composition and size of the cytoplasm. Many therapeutic treatments have been shown to modulate autophagy signalling although it is still unclear if autophagy represents a survival or a suicide mechanism for tumour cells. Tumour growth in response to blocked autophagy as well as tumour growth in response to induced autophagy has been described. Several recent review articles address the differential effect of autophagy manipulation to apoptosis signalling. However, less has been reported about interactions of autophagy manipulation to the outcome of cancer therapy and tumour growth. Therefore, this review tries to fill this gap. We discuss data demonstrating that cellular decisions to autophagy manipulation depend on tumour type, stage, microenvironment, autophagy initiator or inhibitor and combined tumour treatment. Finally, we come to the conclusion that further analyses are necessary before manipulation of autophagic mechanisms can find its way into tumour therapy for improved treatment of patients.
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Affiliation(s)
- Anja Apel
- German Cancer Research Center, Heidelberg, Germany
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