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Pei J, Ding Z, Jiao C, Tao Y, Yang H, Li J. Autophagy in chronic rhinosinusitis with or without nasal polyps. Front Cell Dev Biol 2024; 12:1417735. [PMID: 38933334 PMCID: PMC11199408 DOI: 10.3389/fcell.2024.1417735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 05/13/2024] [Indexed: 06/28/2024] Open
Abstract
Basic research on chronic rhinosinusitis (CRS) has advanced significantly in the past two decades, yet a comprehensive understanding of its pathogenic mechanisms remains elusive. Concurrently, there is a growing interest among scientists in exploring the involvement of autophagy in various human diseases, including tumors and inflammatory conditions. While the role of autophagy in asthma has been extensively studied in airway inflammatory diseases, its significance in CRS with or without nasal polyps (NPs), a condition closely linked to asthma pathophysiology, has also garnered attention, albeit with conflicting findings across studies. This review delves into the role of autophagy in CRS, suggesting that modulating autophagy to regulate inflammatory responses could potentially serve as a novel therapeutic target.
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Affiliation(s)
- Jing Pei
- Department of Otolaryngology, Head and Neck Surgery, The Affiliated Jiangning Hospital With Nanjing Medical University, Nanjing, Jiangsu, China
| | - Zhaoran Ding
- Department of Otolaryngology, Head and Neck Surgery, The Affiliated Jiangning Hospital With Nanjing Medical University, Nanjing, Jiangsu, China
| | - Cheng Jiao
- Department of Otorhinolaryngology Head and Neck Surgery, Northern Jiangsu People’s Hospital Affiliated to Yangzhou University, Yangzhou, Jiangsu, China
| | - Ying Tao
- Department of Blood Purification Center, Northern Jiangsu People’s Hospital Affiliated to Yangzhou University, Yangzhou, Jiangsu, China
| | - Huifen Yang
- Department of Otolaryngology, Head and Neck Surgery, The Affiliated Jiangning Hospital With Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jing Li
- Department of Otolaryngology, Head and Neck Surgery, The Affiliated Jiangning Hospital With Nanjing Medical University, Nanjing, Jiangsu, China
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Draf C, Wyrick T, Chavez E, Pak K, Kurabi A, Leichtle A, Dazert S, Ryan AF. A Screen of Autophagy Compounds Implicates the Proteasome in Mammalian Aminoglycoside-Induced Hair Cell Damage. Front Cell Dev Biol 2021; 9:762751. [PMID: 34765606 PMCID: PMC8576371 DOI: 10.3389/fcell.2021.762751] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 10/05/2021] [Indexed: 12/30/2022] Open
Abstract
Introduction: Autophagy is a degradative pathway to safely break down and recycle dysfunctional cellular components. There is prior evidence of autophagy participation during hair cell (HC) damage. Our goal was to screen compounds targeting different aspects of autophagy for their effects on HC loss due to an ototoxic aminoglycoside, gentamicin (GM). Methods: The SELLECKChem autophagy compound library, consisting of 154 compounds with defined autophagy inducing or inhibitory activity, was used for targeted screening in vitro model of ototoxicity. Organ of Corti from postnatal days 3–5 pou4f3/GFP transgenic mice (HCs express green fluorescent protein) were utilized. The organs were micro-dissected, and basal and middle turns divided into micro-explants individually placed into the single wells of a 96-well plate. Samples were treated with 200 μM of GM plus three dosages of tested compound and cultured for 72 h. Negative controls were treated with media only; positive ototoxicity controls were treated with GM only. Results: The majority of the library compounds had no effect on GM-induced HC loss. However, 18 compounds exhibited a significant, protective effect, two compounds were protective at low dosage but showed enhanced GM toxicity at higher doses and one compound was toxic to HCs in the absence of GM. Conclusions: This study evaluated many autophagy compounds that have not been tested previously on HCs. The disparate results obtained underscore the complexity of autophagy events that can influence HC responses to aminoglycosides, but also implicate the proteosome as an important damage mechanism. The screening results can serve as basis for further studies with protective compounds as potential drug targets.
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Affiliation(s)
- Clara Draf
- Department of Surgery/Otolaryngology, University of California, San Diego, San Diego, CA, United States.,Department of Otolaryngology, St. Elisabeth-Hospital, Ruhr University Bochum, Bochum, Germany
| | - Taylor Wyrick
- Department of Biology, University of California, San Diego, San Diego, CA, United States
| | - Eduardo Chavez
- Department of Surgery/Otolaryngology, University of California, San Diego, San Diego, CA, United States
| | - Kwang Pak
- Department of Surgery/Otolaryngology, University of California, San Diego, San Diego, CA, United States
| | - Arwa Kurabi
- Department of Surgery/Otolaryngology, University of California, San Diego, San Diego, CA, United States
| | - Anke Leichtle
- Department of Otolaryngology, University Medical Center Schleswig-Holstein, Lübeck, Germany
| | - Stefan Dazert
- Department of Otolaryngology, St. Elisabeth-Hospital, Ruhr University Bochum, Bochum, Germany
| | - Allen F Ryan
- Department of Surgery/Otolaryngology, University of California, San Diego, San Diego, CA, United States.,Department of Neurosciences, University of California, San Diego, San Diego, CA, United States.,VA San Diego Healthcare System, San Diego, CA, United States
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3
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Synergetic contributions of viral VP1, VP3, and 3C to activation of the AKT-AMPK-MAPK-MTOR signaling pathway for Seneca Valley virus-induced autophagy. J Virol 2021; 96:e0155021. [PMID: 34757844 DOI: 10.1128/jvi.01550-21] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Seneca Valley virus (SVV), a member of the Picornaviridae family, can activate autophagy via the PERK and ATF6 unfolded protein response pathways and facilitate viral replication; however, the precise molecular mechanism that regulates SVV-induced autophagy remains unclear. Here, we revealed that SVV infection inhibited the phosphorylation of mechanistic target of rapamycin kinase (MTOR) and activated phosphorylation of the serine/threonine kinase AKT. We observed that activating adenosine monophosphate-activated protein kinase (AMPK), extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK), and p38 MAPK signaling by SVV infection promoted autophagy induction and viral replication; additionally, the SVV-induced autophagy was independent of the ULK1 complex. We further evaluated the role of viral protein(s) in the AKT-AMPK-MAPK-MTOR pathway during SVV-induced autophagy and found that VP1 induced autophagy, as evidenced by puncta colocalization with microtubule-associated protein 1 light chain 3 (LC3) in the cytoplasm and enhanced LC3-II levels. This might be associated with the interaction of VP1 with sequestosome 1 and promoting its degradation. In addition, the expression of VP1 enhanced AKT phosphorylation and AMPK phosphorylation, while MTOR phosphorylation was inhibited. These results indicate that VP1 induces autophagy by the AKT-AMPK-MTOR pathway. Additionally, expression of VP3 and 3C was found to activate autophagy induction via the ERK1/2 MAPK-MTOR and p38 MAPK-MTOR pathway. Taken together, our data suggest that SVV-induced autophagy has finely-tuned molecular mechanisms in which VP1, VP3, and 3C contribute synergistically to the AKT-AMPK-MAPK-MTOR pathway. IMPORTANCE Autophagy is an essential cellular catabolic process to sustain normal physiological processes that modulated by a variety of signaling pathways. Invading virus is a stimulus to induce autophagy that regulates viral replication. It has been demonstrated that Seneca Valley virus (SVV) induced autophagy via the PERK and ATF6 unfolded protein response pathways. However, the precise signaling pathway involved in autophagy is still poorly understood. In this study, our results demonstrated that viral proteins VP1, VP3, and 3C contribute synergistically to activation of the AKT-AMPK-MAPK-MTOR signaling pathway for SVV-induced autophagy. These findings reveal systemically the finely-tuned mocleular mechanism of SVV-induced autophagy, thereby facilitating to deeper insight into the development of potential control strategies against SVV infection.
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Wang Q, Lu L, Zeng M, Wang D, Zhang TZ, Xie Y, Gao SB, Fu S, Zhou XP, Wu JX. Rice black-streaked dwarf virus P10 promotes phosphorylation of GAPDH (glyceraldehyde-3-phosphate dehydrogenase) to induce autophagy in Laodelphax striatellus. Autophagy 2021; 18:745-764. [PMID: 34313529 DOI: 10.1080/15548627.2021.1954773] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Macroautophagy/autophagy is an important innate and adaptive immune response that can clear microbial pathogens through guiding their degradation. Virus infection in animals and plants is also known to induce autophagy. However, how virus infection induces autophagy is largely unknown. Here, we provide evidence that the early phase of rice black-streaked dwarf virus (RBSDV) infection in Laodelphax striatellus can also induce autophagy, leading to suppression of RBSDV invasion and accumulation. We have determined that the main capsid protein of RBSDV (P10) is the inducer of autophagy. RBSDV P10 can specifically interact with GAPDH (glyceraldehyde-3-phosphate dehydrogenase), both in vitro and in vivo. Silencing of GAPDH in L. striatellus could significantly reduce the activity of autophagy induced by RBSDV infection. Furthermore, our results also showed that both RBSDV infection and RBSDV P10 alone can promote phosphorylation of AMP-activated protein kinase (AMPK), resulting in GAPDH phosphorylation and relocation of GAPDH from the cytoplasm into the nucleus in midgut cells of L. striatellus or Sf9 insect cells. Once inside the nucleus, phosphorylated GAPDH can activate autophagy to suppress virus infection. Together, these data illuminate the mechanism by which RBSDV induces autophagy in L. striatellus, and indicate that the autophagy pathway in an insect vector participates in the anti-RBSDV innate immune response.
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Affiliation(s)
- Qi Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Lina Lu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Ming Zeng
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Dan Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Tian-Ze Zhang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Yi Xie
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Shi-Bo Gao
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Shuai Fu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
| | - Xue-Ping Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China.,State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, P.R. China
| | - Jian-Xiang Wu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, P.R.China
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5
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Han L, Sun Y, Cao Y, Gao P, Quan Z, Chang Y, Ding J. Analysis of the gene transcription patterns and DNA methylation characteristics of triploid sea cucumbers (Apostichopus japonicus). Sci Rep 2021; 11:7564. [PMID: 33828212 PMCID: PMC8027599 DOI: 10.1038/s41598-021-87278-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 03/26/2021] [Indexed: 02/01/2023] Open
Abstract
Breeding of polyploid aquatic animals is still an important approach and research hotspot for realizing the economic benefits afforded by the improvement of aquatic animal germplasm. To better understand the molecular mechanisms of the growth of triploid sea cucumbers, we performed gene expression and genome-wide comparisons of DNA methylation using the body wall tissue of triploid sea cucumbers using RNA-seq and MethylRAD-seq technologies. We clarified the expression pattern of triploid sea cucumbers and found no dosage effect. DEGs were significantly enriched in the pathways of nucleic acid and protein synthesis, cell growth, cell division, and other pathways. Moreover, we characterized the methylation pattern changes and found 615 differentially methylated genes at CCGG sites and 447 differentially methylated genes at CCWGG sites. Integrative analysis identified 23 genes (such as Guf1, SGT, Col5a1, HAL, HPS1, etc.) that exhibited correlations between promoter methylation and expression. Altered DNA methylation and expression of various genes suggested their roles and potential functional interactions in the growth of triploid sea cucumbers. Our data provide new insights into the epigenetic and transcriptomic alterations of the body wall tissue of triploid sea cucumbers and preliminarily elucidate the molecular mechanism of their growth, which is of great significance for the breeding of fine varieties of sea cucumbers.
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Affiliation(s)
- Lingshu Han
- grid.410631.10000 0001 1867 7333Key Laboratory of Mariculture and Stock Enhancement in North China’s Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, 52 Heishijiao Rd., Dalian, 116023 Liaoning People’s Republic of China ,grid.203507.30000 0000 8950 5267Ningbo University, Ningbo, 315832 Zhejiang People’s Republic of China
| | - Yi Sun
- grid.410631.10000 0001 1867 7333Key Laboratory of Mariculture and Stock Enhancement in North China’s Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, 52 Heishijiao Rd., Dalian, 116023 Liaoning People’s Republic of China
| | - Yue Cao
- grid.410631.10000 0001 1867 7333Key Laboratory of Mariculture and Stock Enhancement in North China’s Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, 52 Heishijiao Rd., Dalian, 116023 Liaoning People’s Republic of China
| | - Pingping Gao
- grid.410631.10000 0001 1867 7333Key Laboratory of Mariculture and Stock Enhancement in North China’s Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, 52 Heishijiao Rd., Dalian, 116023 Liaoning People’s Republic of China
| | - Zijiao Quan
- grid.410631.10000 0001 1867 7333Key Laboratory of Mariculture and Stock Enhancement in North China’s Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, 52 Heishijiao Rd., Dalian, 116023 Liaoning People’s Republic of China
| | - Yaqing Chang
- grid.410631.10000 0001 1867 7333Key Laboratory of Mariculture and Stock Enhancement in North China’s Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, 52 Heishijiao Rd., Dalian, 116023 Liaoning People’s Republic of China
| | - Jun Ding
- grid.410631.10000 0001 1867 7333Key Laboratory of Mariculture and Stock Enhancement in North China’s Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, 52 Heishijiao Rd., Dalian, 116023 Liaoning People’s Republic of China
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6
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He ZH, Pan S, Zheng HW, Fang QJ, Hill K, Sha SH. Treatment With Calcineurin Inhibitor FK506 Attenuates Noise-Induced Hearing Loss. Front Cell Dev Biol 2021; 9:648461. [PMID: 33777956 PMCID: PMC7994600 DOI: 10.3389/fcell.2021.648461] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 02/11/2021] [Indexed: 11/13/2022] Open
Abstract
Attenuation of noise-induced hair cell loss and noise-induced hearing loss (NIHL) by treatment with FK506 (tacrolimus), a calcineurin (CaN/PP2B) inhibitor used clinically as an immunosuppressant, has been previously reported, but the downstream mechanisms of FK506-attenuated NIHL remain unknown. Here we showed that CaN immunolabeling in outer hair cells (OHCs) and nuclear factor of activated T-cells isoform c4 (NFATc4/NFAT3) in OHC nuclei are significantly increased after moderate noise exposure in adult CBA/J mice. Consequently, treatment with FK506 significantly reduces moderate-noise-induced loss of OHCs and NIHL. Furthermore, induction of reactive oxygen species (ROS) by moderate noise was significantly diminished by treatment with FK506. In agreement with our previous finding that autophagy marker microtubule-associated protein light chain 3B (LC3B) does not change in OHCs under conditions of moderate-noise-induced permanent threshold shifts, treatment with FK506 increases LC3B immunolabeling in OHCs after exposure to moderate noise. Additionally, prevention of NIHL by treatment with FK506 was partially abolished by pretreatment with LC3B small interfering RNA. Taken together, these results indicate that attenuation of moderate-noise-induced OHC loss and hearing loss by FK506 treatment occurs not only via inhibition of CaN activity but also through inhibition of ROS and activation of autophagy.
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Affiliation(s)
| | | | | | | | | | - Su-Hua Sha
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States
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7
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Jahangiri L, Ishola T, Pucci P, Trigg RM, Pereira J, Williams JA, Cavanagh ML, Gkoutos GV, Tsaprouni L, Turner SD. The Role of Autophagy and lncRNAs in the Maintenance of Cancer Stem Cells. Cancers (Basel) 2021; 13:cancers13061239. [PMID: 33799834 PMCID: PMC7998932 DOI: 10.3390/cancers13061239] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/06/2021] [Accepted: 03/08/2021] [Indexed: 12/18/2022] Open
Abstract
Simple Summary Cancer stem cells (CSCs) represent a distinct cancer subpopulation that can influence the tumour microenvironment, in addition to cancer progression and relapse. A multitude of factors including CSC properties, long noncoding RNAs (lncRNAs), and autophagy play pivotal roles in maintaining CSCs. We discuss the methods of detection of CSCs and how our knowledge of regulatory and cellular processes, and their interaction with the microenvironment, may lead to more effective targeting of these cells. Autophagy and lncRNAs can regulate several cellular functions, thereby promoting stemness factors and CSC properties, hence understanding this triangle and its associated signalling networks can lead to enhanced therapy response, while paving the way for the development of novel therapeutic approaches. Abstract Cancer stem cells (CSCs) possess properties such as self-renewal, resistance to apoptotic cues, quiescence, and DNA-damage repair capacity. Moreover, CSCs strongly influence the tumour microenvironment (TME) and may account for cancer progression, recurrence, and relapse. CSCs represent a distinct subpopulation in tumours and the detection, characterisation, and understanding of the regulatory landscape and cellular processes that govern their maintenance may pave the way to improving prognosis, selective targeted therapy, and therapy outcomes. In this review, we have discussed the characteristics of CSCs identified in various cancer types and the role of autophagy and long noncoding RNAs (lncRNAs) in maintaining the homeostasis of CSCs. Further, we have discussed methods to detect CSCs and strategies for treatment and relapse, taking into account the requirement to inhibit CSC growth and survival within the complex backdrop of cellular processes, microenvironmental interactions, and regulatory networks associated with cancer. Finally, we critique the computationally reinforced triangle of factors inclusive of CSC properties, the process of autophagy, and lncRNA and their associated networks with respect to hypoxia, epithelial-to-mesenchymal transition (EMT), and signalling pathways.
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Affiliation(s)
- Leila Jahangiri
- Department of Life Sciences, Birmingham City University, Birmingham B15 3TN, UK; (T.I.); (M.L.C.); (L.T.)
- Division of Cellular and Molecular Pathology, Department of Pathology, University of Cambridge, Cambridge CB2 0QQ, UK; (P.P.); (R.M.T.); (S.D.T.)
- Correspondence: (L.J.); (G.V.G.)
| | - Tala Ishola
- Department of Life Sciences, Birmingham City University, Birmingham B15 3TN, UK; (T.I.); (M.L.C.); (L.T.)
| | - Perla Pucci
- Division of Cellular and Molecular Pathology, Department of Pathology, University of Cambridge, Cambridge CB2 0QQ, UK; (P.P.); (R.M.T.); (S.D.T.)
| | - Ricky M. Trigg
- Division of Cellular and Molecular Pathology, Department of Pathology, University of Cambridge, Cambridge CB2 0QQ, UK; (P.P.); (R.M.T.); (S.D.T.)
- Department of Functional Genomics, GlaxoSmithKline, Stevenage SG1 2NY, UK
| | - Joao Pereira
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA;
| | - John A. Williams
- Institute of Translational Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham B15 2TH, UK;
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2SY, UK
| | - Megan L. Cavanagh
- Department of Life Sciences, Birmingham City University, Birmingham B15 3TN, UK; (T.I.); (M.L.C.); (L.T.)
| | - Georgios V. Gkoutos
- Institute of Translational Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham B15 2TH, UK;
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2SY, UK
- Mammalian Genetics Unit, Medical Research Council Harwell Institute, Oxfordshire OX110RD, UK
- MRC Health Data Research Midlands, University of Birmingham, Birmingham B15 2TT, UK
- NIHR Experimental Cancer Medicine Centre, Birmingham B15 2TT, UK
- NIHR Surgical Reconstruction and Microbiology Research Centre, Birmingham B15 2TT, UK
- NIHR Biomedical Research Centre, Birmingham B15 2TT, UK
- Correspondence: (L.J.); (G.V.G.)
| | - Loukia Tsaprouni
- Department of Life Sciences, Birmingham City University, Birmingham B15 3TN, UK; (T.I.); (M.L.C.); (L.T.)
| | - Suzanne D. Turner
- Division of Cellular and Molecular Pathology, Department of Pathology, University of Cambridge, Cambridge CB2 0QQ, UK; (P.P.); (R.M.T.); (S.D.T.)
- Central European Institute of Technology (CEITEC), Masaryk University, 625 00 Brno, Czech Republic
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Wang SH, Wang K, Zhao K, Hua SC, Du J. The Structure, Function, and Mechanisms of Action of Enterovirus Non-structural Protein 2C. Front Microbiol 2020; 11:615965. [PMID: 33381104 PMCID: PMC7767853 DOI: 10.3389/fmicb.2020.615965] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 11/23/2020] [Indexed: 12/16/2022] Open
Abstract
Enteroviruses are a group of RNA viruses belonging to the family Picornaviridae. They include human enterovirus groups A, B, C, and D as well as non-human enteroviruses. Enterovirus infections can lead to hand, foot, and mouth disease and herpangina, whose clinical manifestations are often mild, although some strains can result in severe neurological complications such as encephalitis, myocarditis, meningitis, and poliomyelitis. To date, research on enterovirus non-structural proteins has mainly focused on the 2A and 3C proteases and 3D polymerase. However, another non-structural protein, 2C, is the most highly conserved protein, and plays a vital role in the enterovirus life cycle. There are relatively few studies on this protein. Previous studies have demonstrated that enterovirus 2C is involved in virus uncoating, host cell membrane rearrangements, RNA replication, encapsidation, morphogenesis, ATPase, helicase, and chaperoning activities. Despite ongoing research, little is known about the pathogenesis of enterovirus 2C proteins in viral replication or in the host innate immune system. In this review, we discuss and summarize the current understanding of the structure, function, and mechanism of the enterovirus 2C proteins, focusing on the key mutations and motifs involved in viral infection, replication, and immune regulation. We also focus on recent progress in research into the role of 2C proteins in regulating the pattern recognition receptors and type I interferon signaling pathway to facilitate viral replication. Given these functions and mechanisms, the potential application of the 2C proteins as a target for anti-viral drug development is also discussed. Future studies will focus on the determination of more crystal structures of enterovirus 2C proteins, which might provide more potential targets for anti-viral drug development against enterovirus infections.
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Affiliation(s)
- Shao-Hua Wang
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China
| | - Kuan Wang
- Department of Neurotrauma, The First Hospital of Jilin University, Changchun, China
| | - Ke Zhao
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China
| | - Shu-Cheng Hua
- Department of Internal Medicine, The First Hospital of Jilin University, Changchun, China
| | - Juan Du
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China.,Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
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9
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López Giuliani AC, Hernández E, Tohmé MJ, Taisne C, Roldán JS, García Samartino C, Lussignol M, Codogno P, Colombo MI, Esclatine A, Delgui LR. Human Cytomegalovirus Inhibits Autophagy of Renal Tubular Epithelial Cells and Promotes Cellular Enlargement. Front Cell Infect Microbiol 2020; 10:474. [PMID: 33042861 PMCID: PMC7522221 DOI: 10.3389/fcimb.2020.00474] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 07/31/2020] [Indexed: 12/26/2022] Open
Abstract
Human Cytomegalovirus (HCMV) is a frequent opportunistic pathogen in immunosuppressed patients, which can be involved in kidney allograft dysfunction and rejection. In order to study the pathophysiology of HCMV renal diseases, we concentrated on the impact of HCMV infection on human renal tubular epithelial HK-2 cells. Our aim was to develop a model of infection of HK-2 cells by using the viral strain TB40/E, that contains the extended cell tropism of clinical isolates and the efficient viral multiplication in cell culture of laboratory-adapted strains. We observed that HK-2 cells can be infected by HCMV and expressed viral antigens, but they do not produce extracellular viral particles. We then studied the interplay of HCMV with ciliogenesis and autophagy. Primary cilium (PC) is a stress sensor important to maintain renal tissue homeostasis that projects from the apical side into the lumen of tubule cells. PC formation and length were not modified by HCMV infection. Autophagy, another stress response process critically required for normal kidney functions, was inhibited by HCMV in HK-2 cells with a reduction in the autophagic flux. HCMV classically induces an enlargement of infected cells in vivo and in vitro, and we observed that HCMV infection led to an enlargement of the HK-2 cell volume. Our results constitute therefore an excellent starting point to further explore the role of these mechanisms in renal cells dysfunction.
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Affiliation(s)
- Ana C López Giuliani
- Facultad de Ciencias Médicas, IHEM, Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina.,Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Eva Hernández
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - María J Tohmé
- Facultad de Ciencias Médicas, IHEM, Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina.,Facultad de Farmacia y Bioquímica, Universidad Juan Agustín Maza, Mendoza, Argentina
| | - Clémence Taisne
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Julieta S Roldán
- Instituto de Investigaciones Biotecnológicas (IIBIO), Universidad de San Martín, Buenos Aires, Argentina
| | | | - Marion Lussignol
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Patrice Codogno
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris, France.,The Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - María I Colombo
- Facultad de Ciencias Médicas, IHEM, Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina.,Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Audrey Esclatine
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Laura R Delgui
- Facultad de Ciencias Médicas, IHEM, Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina.,Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina
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10
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Ardali R, Kazemipour N, Nazifi S, Bagheri Lankarani K, Razeghian Jahromi I, Sepehrimanesh M. Pathophysiological role of Atg5 in human ulcerative colitis. Intest Res 2020; 18:421-429. [PMID: 32380583 PMCID: PMC7609390 DOI: 10.5217/ir.2019.00120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/19/2020] [Accepted: 01/27/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND/AIMS Ulcerative colitis (UC), along with Crohn's disease, is one of the main types of inflammatory bowel disease (IBD). On the other hand, deregulated autophagy is involved in many chronic diseases, including IBD. In this study, we aimed to investigate the role of Atg5 and microRNA-181a (miR-181a) in the pathophysiology of UC. METHODS Colon biopsy, stool, and blood samples of 6 men and 9 women were confirmed for UC. Also, 13 men and 17 women were selected as healthy control (HC). Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry were used to measure the Atg-5 content of the colon biopsies. Besides, the serum and stool levels of Atg5 were measured using ELISA. Moreover, the total RNA of blood cells was extracted and evaluated for the expression of miR-181a. RESULTS We found 1.2 ng/mL versus 0.46 ng/mL, 0.34 ng/mL versus 0.24 ng/mL, and 0.082 ng/mL versus 0.062 ng/mL of Atg5 in stool, intestinal tissue, and serum of UC and HCs, respectively. There was no significant difference in the expression of miR-181a in the blood samples of UC and HCs. Immunohistochemistry showed high positivity without any significant difference between the 2 groups in the quantitative analysis. CONCLUSIONS The significant difference observed between the stool Atg5 content of the HCs and UC patients may provide new insight into using this protein as a diagnostic biomarker, however, considering the small size of our studied population further studies are needed.
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Affiliation(s)
- Razieh Ardali
- Biochemistry Division, Department of Basic Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Nasrin Kazemipour
- Biochemistry Division, Department of Basic Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Saeed Nazifi
- Clinical Pathology Division, Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | | | | | - Masood Sepehrimanesh
- New Iberia Research Center, University of Louisiana at Lafayette, Lafayette, LA, USA
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11
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A dual death/survival role of autophagy in the adult ovary of Lagostomus maximus (Mammalia- Rodentia). PLoS One 2020; 15:e0232819. [PMID: 32469908 PMCID: PMC7259749 DOI: 10.1371/journal.pone.0232819] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 04/22/2020] [Indexed: 12/16/2022] Open
Abstract
Follicular atresia is a cell death event that occurs in the great majority of follicles before ovulation in the mature mammalian ovary. Germ cell loss has been mainly associated to apoptosis although autophagy also seems to be at play. Aimed to increase our understanding on the possible cooperating role of autophagy and apoptosis in follicular atresia and/or follicular survival, we analyzed both programmed cell death mechanisms in a rodent model, the South American plains vizcacha, Lagostomus maximus. Female vizcacha shows highly suppressed apoptosis-dependent follicular atresia in the adult ovary, with continuous folliculogenesis and massive polyovulation. This strategy of massive ovulation requires a permanent remodeling of the ovarian architecture to maintain the availability of quiescent primordial follicles throughout the individual's reproductive lifespan. We report here our analysis of autophagy (BECN1, LAMP1 and LC3B-I/II) and apoptosis (BCL2 and ACTIVE CASPASE-3) markers which revealed interactive behaviors between both processes, with autophagy promoting survival or cell death depending on the ovarian structure. Strong BECN1, LC3B-II and LAMP1 staining was observed in atretic follicles and degenerating corpora lutea that also expressed nuclear ACTIVE CASPASE-3. Healthy follicles showed a slight expression of autophagy proteins but a strong expression of BCL2 and no detectable ACTIVE CASPASE-3. Transmission electron microscopy revealed a high formation of autophagosomes, autolysosomes and lysosomes in atretic follicles and degenerating corpora lutea and a low number of autophagic vesicles in normal follicles. The co-expression of LC3B-BECN1, LC3B-LAMP1 and LC3B-ACTIVE CASPASE-3 was only detected in atretic follicles and degenerating corpora lutea, while co-expression of BCL2-BECN1 was only observed in normal follicles. We propose that autophagy could act as a mechanism to eliminate altered follicles and remnant corpora lutea providing the necessary space for maturation of primordial follicles that continuously enter the growing follicular pool to sustain massive ovulation.
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12
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Identification of Circular RNAs Regulating Islet β-Cell Autophagy in Type 2 Diabetes Mellitus. BIOMED RESEARCH INTERNATIONAL 2019; 2019:4128315. [PMID: 31815137 PMCID: PMC6878796 DOI: 10.1155/2019/4128315] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 08/30/2019] [Accepted: 09/29/2019] [Indexed: 12/13/2022]
Abstract
This study is to identify the circular RNA (circRNA) expression profile that is functionally related to pancreatic islet β-cell autophagy and their potential regulation mechanisms in type 2 diabetes mellitus (T2DM). T2DM rat model was constructed by administration of high-fat and high-sugar diet. β-cells were isolated from islets by flow cytometry. CircRNA expression profile in β-cells was detected by circRNA microarrays, and the differentially expressed circRNAs were identified and validated by qRT-PCR. MicroRNA (miRNA) target prediction software and multiple bioinformatic approaches were used to construct a map of circRNA-miRNA interactions for the differentially expressed circRNAs. A total of 825 differentially expressed circular transcripts were identified in T2DM rats compared with control rats, among which 388 were upregulated and 437 were downregulated. Ten circRNAs were identified to have significant differences by qRT-PCR. GO analysis enriched terms such as organelle membrane and protein binding and the top enriched pathways for the circRNAs included MAPK signaling pathway. The differentially expressed circRNAs might involve in MAPK signaling pathway, apoptosis, and Ras signaling pathway. We speculate that these circRNAs, especially rno_circRNA_008565, can regulate the autophagy of islet β-cells via interactions with miRNA. Dysregulation of several circRNAs may play a role in T2DM development, and rno_circRNA_008565 may be a potential regulator of β-cell autophagy.
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13
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Telomerase Impinges on the Cellular Response to Oxidative Stress Through Mitochondrial ROS-Mediated Regulation of Autophagy. Int J Mol Sci 2019; 20:ijms20061509. [PMID: 30917518 PMCID: PMC6470917 DOI: 10.3390/ijms20061509] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/15/2019] [Accepted: 03/15/2019] [Indexed: 12/30/2022] Open
Abstract
Telomerase has cellular functions beyond telomere stabilization, including a role in mitochondria. The function of the catalytic component—TERT—in mitochondria is still unknown, but it seems to play a role in the response to oxidative stress. Here, we interrogated the role of the subcellular localization of TERT to the response to hydrogen peroxide (H2O2) treatment. Using normal human fibroblasts (NHF) expressing non-tagged wild type (WT) human TERT (hTERT) or nuclear localization and function (nuchTERT), a mutant that we previously described as being competent in telomere elongation, while not being able to localize to mitochondria, we found the differential activation of autophagy as a function of hTERT’s subcellular localization. Specifically, we found that only cells expressing the mutant had significant increases in autophagy markers as a response to H2O2 challenge. Either the reintroduction of the mitochondrial pool of hTERT or the expression of mitochondrially-targeted catalase in mutant cells blunted the autophagic response under oxidative stress. Interestingly, autophagy activation was also associated with decreased levels of mitochondrial DNA damage. Taken together, these results suggest that the loss of hTERT in mitochondria initiates a signaling cascade that allows for cells to adapt to and cope with the lack of mitochondrial telomerase. Such effects also influence the cellular response to oxidative damage.
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14
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Aghaei M, Motallebnezhad M, Ghorghanlu S, Jabbari A, Enayati A, Rajaei M, Pourabouk M, Moradi A, Alizadeh AM, Khori V. Targeting autophagy in cardiac ischemia/reperfusion injury: A novel therapeutic strategy. J Cell Physiol 2019; 234:16768-16778. [PMID: 30807647 DOI: 10.1002/jcp.28345] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/17/2019] [Accepted: 01/22/2019] [Indexed: 12/31/2022]
Abstract
Acute myocardial infarction (AMI) is one of the leading causes of morbidity worldwide. Myocardial reperfusion is known as an effective therapeutic choice against AMI. However, reperfusion of blood flow induces ischemia/reperfusion (I/R) injury through different complex processes including ion accumulation, disruption of mitochondrial membrane potential, the formation of reactive oxygen species, and so forth. One of the processes that gets activated in response to I/R injury is autophagy. Indeed, autophagy acts as a "double-edged sword" in the pathology of myocardial I/R injury and there is a controversy about autophagy being beneficial or detrimental. On the basis of the autophagy effect and regulation on myocardial I/R injury, many studies targeted it as a therapeutic strategy. In this review, we discuss the role of autophagy in I/R injury and its targeting as a therapeutic strategy.
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Affiliation(s)
- Mehrdad Aghaei
- Rheumatology Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Morteza Motallebnezhad
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Immunology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.,Student Research Committee, Iran University of Medical Sciences, Tehran, Iran
| | - Sajjad Ghorghanlu
- Ischemic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Ali Jabbari
- Ischemic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Ayesheh Enayati
- Ischemic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran.,Department of Pharmacognosy, Faculty of Pharmacy and Medicinal Plants Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Rajaei
- Ischemic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Mona Pourabouk
- Ischemic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Alireza Moradi
- Department of Physiology, Medical School, Ardabil University of Medical Sciences, Ardabil, Iran
| | | | - Vahid Khori
- Ischemic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran
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15
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Lee KH, Lee J, Woo J, Lee CH, Yoo CG. Proteasome Inhibitor-Induced IκB/NF-κB Activation is Mediated by Nrf2-Dependent Light Chain 3B Induction in Lung Cancer Cells. Mol Cells 2018; 41:1008-1015. [PMID: 30396235 PMCID: PMC6315323 DOI: 10.14348/molcells.2018.0277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/30/2018] [Accepted: 09/13/2018] [Indexed: 11/27/2022] Open
Abstract
IκB, a cytoplasmic inhibitor of nuclear factor-κB (NF-κB), is reportedly degraded via the proteasome. However, we recently found that long-term incubation with proteasome inhibitors (PIs) such as PS-341 or MG132 induces IκBα degradation via an alternative pathway, lysosome, which results in NF-κB activation and confers resistance to PI-induced lung cancer cell death. To enhance the anti-cancer efficacy of PIs, elucidation of the regulatory mechanism of PI-induced IκBα degradation is necessary. Here, we demonstrated that PI upregulates nuclear factor (erythroid-derived 2)-like 2 (Nrf2) via both de novo protein synthesis and Kelch-like ECH-associated protein 1 (KEAP1) degradation, which is responsible for IκBα degradation via macroautophagy activation. PIs increased the protein level of light chain 3B (LC3B, macroautophagy marker), but not lysosome-associated membrane protein 2a (Lamp2a, the receptor for chaperone-mediated autophagy) in NCI-H157 and A549 lung cancer cells. Pretreatment with macroautophagy inhibitor or knock-down of LC3B blocked PI-induced IκBα degradation. PIs up-regulated Nrf2 by increasing its transcription and mediating degradation of KEAP1 (cytoplasmic inhibitor of Nrf2). Overexpression of dominant-negative Nrf2, which lacks an N-terminal transactivating domain, or knock-down of Nrf2 suppressed PI-induced LC3B protein expression and subsequent IκBα degradation. Thus, blocking of the Nrf2 pathway enhanced PI-induced cell death. These findings suggest that Nrf2-driven induction of LC3B plays an essential role in PI-induced activation of the IκB/NF-κB pathway, which attenuates the anti-tumor efficacy of PIs.
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Affiliation(s)
- Kyoung-Hee Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul,
Korea
| | - Jungsil Lee
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul,
Korea
| | - Jisu Woo
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul,
Korea
| | - Chang-Hoon Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul,
Korea
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul,
Korea
| | - Chul-Gyu Yoo
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, Seoul,
Korea
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul,
Korea
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16
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Lup-20(29)-en-3β,28-di-yl-nitrooxy acetate affects MCF-7 proliferation through the crosstalk between apoptosis and autophagy in mitochondria. Cell Death Dis 2018; 9:241. [PMID: 29445224 PMCID: PMC5833777 DOI: 10.1038/s41419-017-0255-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 12/04/2017] [Accepted: 12/06/2017] [Indexed: 12/19/2022]
Abstract
Betulin (BT), a pentacyclic lupine-type triterpenoid natural product, possesses antitumor activity in various types of cancers. However, its clinical development was discouraged due to its low biological activities and poor solubility. We prepared lup-20(29)-en-3β,28-di-yl-nitrooxy acetate (NBT), a derivative of BT, that was chemically modified at position 3 of ring A and C-28 by introducing a NO-releasing moiety. This study mainly explored the mechanism of NBT in treating breast cancer through the crosstalk between apoptosis and autophagy in mitochondria. NBT possessed a potent antiproliferative activity in MCF-7 cells both in vitro and in vivo. Mechanically, NBT affected cell death through the mitochondrial apoptosis pathway and autophagy. NBT induced cell cycle arrest in the G0/G1 phase by decreasing the expression of cyclin D1. It also induced mitochondrial apoptosis by increasing the expression of Bax, caspase-9, and poly(ADP-ribose) polymerase and mitochondrial membrane potential loss and leaks of cytochrome c (Cyt C) from mitochondria in MCF-7 cells and decreasing the expression of mitochondrial Bcl-2. We further demonstrated whether chloroquine (CQ), which inhibits the degradation of autophagosome induced by NBT, affects the proliferation of MCF-7 cells compared with NBT. The experiments inferred that the combination of NBT and CQ significantly promoted MCF-7 cell mitochondria to divide and Cyt C to be released from mitochondria to the cytoplasm, resulting in an increased apoptosis rate. The in vivo experiments showed that NBT inhibited the growth of MCF-7 tumor via the apoptosis pathway, and its effect was similar to 5-fluorouracil.
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17
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Sun YC, Wang YY, Sun XF, Cheng SF, Li L, Zhao Y, Shen W, Chen H. The role of autophagy during murine primordial follicle assembly. Aging (Albany NY) 2018; 10:197-211. [PMID: 29410391 PMCID: PMC5842841 DOI: 10.18632/aging.101376] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 01/30/2018] [Indexed: 11/25/2022]
Abstract
It is generally accepted that significant germ cell loss occurs during the establishment of the primordial follicle pool in most mammalian ovaries around the time of birth. However, the underlying mechanisms responsible for these processes remain largely unknown. In this investigation, we explored the role of autophagy during the establishment of the primordial follicle pool and found that autophagy was active in this process. Our data suggested that 17.5 dpc ovaries treated with rapamycin displayed a delay in germ cell cyst breakdown resulting in more oocytes at day 5 of treatment, while, ovaries that treated with 3-MA showed the opposite effect. We found that rapamycin treatment promoted autophagy and depressed cell apoptosis increasing the number of NOBOX positive oocytes. Furthermore, our results also revealed that epigenetic regulator, Sirt1, plays a role in germ cell loss. An epigenetic inhibitor or RNAi treatment of Sirt1, showed an increased level of H4K16ac and a decreased level of autophagy. Thus, these data indicate that autophagy prevents germ cell over loss during the establishment of primordial follicle pool, and this process may be influenced by Sirt1-invovled epigenetic regulation.
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Affiliation(s)
- Yuan-Chao Sun
- College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling Shaanxi, China
- Institute of Reproductive Sciences, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Yong-Yong Wang
- Department of Reproductive Medicine, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China
| | - Xiao-Feng Sun
- Institute of Reproductive Sciences, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Shun-Feng Cheng
- Institute of Reproductive Sciences, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Lan Li
- Institute of Reproductive Sciences, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Yong Zhao
- Institute of Reproductive Sciences, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Wei Shen
- Institute of Reproductive Sciences, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Hong Chen
- College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling Shaanxi, China
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18
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Yin H, Zhao L, Jiang X, Li S, Huo H, Chen H. DEV induce autophagy via the endoplasmic reticulum stress related unfolded protein response. PLoS One 2017; 12:e0189704. [PMID: 29272280 PMCID: PMC5741216 DOI: 10.1371/journal.pone.0189704] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 11/30/2017] [Indexed: 01/25/2023] Open
Abstract
Duck enteritis virus (DEV) can infect ducks, geese, and many other poultry species and leads to acute, septic and highly fatal infectious disease. Autophagy is an evolutionarily ancient pathway that plays an important role in many viral infections. We previously reported that DEV infection induces autophagy for its own benefit, but how this occurs remains unclear. In this study, endoplasmic reticulum (ER) stress was triggered by DEV infection, as demonstrated by the increased expression of the ER stress marker glucose-regulated protein 78 (GRP78) and the dilated morphology of the ER. Pathways associated with the unfolded protein response (UPR), including the PKR-like ER protein kinase (PERK) and inositol-requiring enzyme 1 (IRE1) pathways, but not the activating transcription factor 6 (ATF6) pathway, were activated in DEV-infected duck embryo fibroblast (DEF) cells. In addition, the knockdown of both PERK and IRE1 by small interfering RNAs (siRNAs) reduced the level of LC3-II and viral yields, which suggested that the PERK-eukaryotic initiation factor 2α (eIF2α) and IRE1-x-box protein1 (XBP1) pathways may contribute to DEV-induced autophagy. Collectively, these data offer new insight into the mechanisms of DEV -induced autophagy through activation of the ER stress-related UPR pathway.
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Affiliation(s)
- Haichang Yin
- State Key Laboratory of Veterinary Biotechnology, Heilongjiang Provincial Key Laboratory of Laboratory Animal and Comparative Medicine, Harbin Veterinary Research Institute, the Chinese Academy of Agriculture Science, Harbin, P. R. China
| | - Lili Zhao
- State Key Laboratory of Veterinary Biotechnology, Heilongjiang Provincial Key Laboratory of Laboratory Animal and Comparative Medicine, Harbin Veterinary Research Institute, the Chinese Academy of Agriculture Science, Harbin, P. R. China
| | - Xinjie Jiang
- State Key Laboratory of Veterinary Biotechnology, Heilongjiang Provincial Key Laboratory of Laboratory Animal and Comparative Medicine, Harbin Veterinary Research Institute, the Chinese Academy of Agriculture Science, Harbin, P. R. China
| | - Siqi Li
- State Key Laboratory of Veterinary Biotechnology, Heilongjiang Provincial Key Laboratory of Laboratory Animal and Comparative Medicine, Harbin Veterinary Research Institute, the Chinese Academy of Agriculture Science, Harbin, P. R. China
| | - Hong Huo
- State Key Laboratory of Veterinary Biotechnology, Heilongjiang Provincial Key Laboratory of Laboratory Animal and Comparative Medicine, Harbin Veterinary Research Institute, the Chinese Academy of Agriculture Science, Harbin, P. R. China
| | - Hongyan Chen
- State Key Laboratory of Veterinary Biotechnology, Heilongjiang Provincial Key Laboratory of Laboratory Animal and Comparative Medicine, Harbin Veterinary Research Institute, the Chinese Academy of Agriculture Science, Harbin, P. R. China
- * E-mail: hy
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19
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Bhore N, Wang BJ, Chen YW, Liao YF. Critical Roles of Dual-Specificity Phosphatases in Neuronal Proteostasis and Neurological Diseases. Int J Mol Sci 2017; 18:ijms18091963. [PMID: 28902166 PMCID: PMC5618612 DOI: 10.3390/ijms18091963] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/01/2017] [Accepted: 09/07/2017] [Indexed: 12/31/2022] Open
Abstract
Protein homeostasis or proteostasis is a fundamental cellular property that encompasses the dynamic balancing of processes in the proteostasis network (PN). Such processes include protein synthesis, folding, and degradation in both non-stressed and stressful conditions. The role of the PN in neurodegenerative disease is well-documented, where it is known to respond to changes in protein folding states or toxic gain-of-function protein aggregation. Dual-specificity phosphatases have recently emerged as important participants in maintaining balance within the PN, acting through modulation of cellular signaling pathways that are involved in neurodegeneration. In this review, we will summarize recent findings describing the roles of dual-specificity phosphatases in neurodegeneration and offer perspectives on future therapeutic directions.
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Affiliation(s)
- Noopur Bhore
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang-Ming University and Academia Sinica, Taipei 11529, Taiwan.
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
| | - Bo-Jeng Wang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
| | - Yun-Wen Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
| | - Yung-Feng Liao
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang-Ming University and Academia Sinica, Taipei 11529, Taiwan.
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
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20
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Korovila I, Hugo M, Castro JP, Weber D, Höhn A, Grune T, Jung T. Proteostasis, oxidative stress and aging. Redox Biol 2017; 13:550-567. [PMID: 28763764 PMCID: PMC5536880 DOI: 10.1016/j.redox.2017.07.008] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 07/04/2017] [Accepted: 07/09/2017] [Indexed: 12/21/2022] Open
Abstract
The production of reactive species is an inevitable by-product of metabolism and thus, life itself. Since reactive species are able to damage cellular structures, especially proteins, as the most abundant macromolecule of mammalian cells, systems are necessary which regulate and preserve a functional cellular protein pool, in a process termed “proteostasis”. Not only the mammalian protein pool is subject of a constant turnover, organelles are also degraded and rebuild. The most important systems for these removal processes are the “ubiquitin-proteasomal system” (UPS), the central proteolytic machinery of mammalian cells, mainly responsible for proteostasis, as well as the “autophagy-lysosomal system”, which mediates the turnover of organelles and large aggregates. Many age-related pathologies and the aging process itself are accompanied by a dysregulation of UPS, autophagy and the cross-talk between both systems. This review will describe the sources and effects of oxidative stress, preservation of cellular protein- and organelle-homeostasis and the effects of aging on proteostasis in mammalian cells.
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Affiliation(s)
- Ioanna Korovila
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany
| | - Martín Hugo
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany
| | - José Pedro Castro
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research (DZD), 85764 Muenchen-Neuherberg, Germany; Faculty of Medicine, Department of Biomedicine, University of Porto, 4200-319, Portugal; Institute for Innovation and Health Research (I3S), Aging and Stress Group, R. Alfredo Allen, 4200-135 Porto, Portugal
| | - Daniela Weber
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; NutriAct - Competence Cluster Nutrition Research Berlin-Potsdam, 14558 Nuthetal, Germany
| | - Annika Höhn
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research (DZD), 85764 Muenchen-Neuherberg, Germany
| | - Tilman Grune
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research (DZD), 85764 Muenchen-Neuherberg, Germany; German Center for Cardiovascular Research (DZHK), 10117 Berlin, Germany; NutriAct - Competence Cluster Nutrition Research Berlin-Potsdam, 14558 Nuthetal, Germany
| | - Tobias Jung
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Cardiovascular Research (DZHK), 10117 Berlin, Germany.
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21
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Sun YC, Sun XF, Dyce PW, Shen W, Chen H. The role of germ cell loss during primordial follicle assembly: a review of current advances. Int J Biol Sci 2017; 13:449-457. [PMID: 28529453 PMCID: PMC5436565 DOI: 10.7150/ijbs.18836] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 01/25/2017] [Indexed: 12/27/2022] Open
Abstract
In most female mammals, early germline development begins with the appearance of primordial germ cells (PGCs), and develops to form mature oocytes following several vital processes. It remains well accepted that significant germ cell apoptosis and oocyte loss takes place around the time of birth. The transition of the ovarian environment from fetal to neonatal, coincides with the loss of germ cells and the timing of follicle formation. All told it is common to lose approximately two thirds of germ cells during this transition period. The current consensus is that germ cell loss can be attributed, at least in part, to programmed cell death (PCD). Recently, autophagy has been implicated as playing a part in germ cell loss during the time of parturition. In this review, we discuss the major opinions and mechanisms of mammalian ovarian PCD during the process of germ cell loss. We also pay close attention to the function of autophagy in germ cell loss, and speculate that autophagy may also serve as a critical and necessary process during the establishment of primordial follicle pool.
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Affiliation(s)
- Yuan-Chao Sun
- College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling Shaanxi 712100, China
| | - Xiao-Feng Sun
- Institute of Reproductive Sciences, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China
| | - Paul W Dyce
- Department of Animal Sciences, Auburn University, Auburn, AL 36849, USA
| | - Wei Shen
- Institute of Reproductive Sciences, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China
| | - Hong Chen
- College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling Shaanxi 712100, China
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Kim YJ, Tian C, Kim J, Shin B, Choo OS, Kim YS, Choung YH. Autophagic flux, a possible mechanism for delayed gentamicin-induced ototoxicity. Sci Rep 2017; 7:41356. [PMID: 28145495 PMCID: PMC5286410 DOI: 10.1038/srep41356] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 12/20/2016] [Indexed: 12/20/2022] Open
Abstract
Aminoglycoside antibiotics including gentamicin (GM) induce delayed ototoxic effects such as hearing loss after long-term use, unlike the early-onset ototoxicity caused by cisplatin. The purpose of the study was to identify the mechanism of the delayed GM-induced ototoxicity by exploring the role of autophagy in vitro and in vivo. Treating HEI-OC1 auditory cells with GM led to a time-dependent increase of the autophagosome marker LC3-II, which was accompanied by cell death. In contrast, cisplatin and penicillin caused a rapid increase and had no effect on LC3-II levels, respectively. LC3-II-expressing autophagosomes co-localized with the labeled GM. GM-treated autophagosomes expressed reduced levels of Rab7, which is necessary for the fusion of autophagosomes with lysosomes. When the autophagic flux enhancer rapamycin was applied to GM-treated cells, Rab7 and the lysosomal enzyme cathepsin D were upregulated, and increased cell survival was observed. In animal studies, the intraperitoneal injection of GM worsened hearing thresholds and induced the accumulation of LC3 in the organ of Corti. This hearing impairment was attenuated by rapamycin. These findings suggest that the delayed onset-ototoxicity of GM may be closely related to the accumulation of autophagosomes via impaired autophagy. This GM-induced auditory cell death could be inhibited by enhancing autophagic flux.
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Affiliation(s)
- Yeon Ju Kim
- Department of Otolaryngology, Ajou University School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea
| | - Chunjie Tian
- Department of Otolaryngology, Dali Bai Autonomous Prefecture People's Hospital, Renminnan road 35, Dali, Yunnan 671000, China
| | - Jangho Kim
- Department of Rural and Biosystems Engineering, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Beomyong Shin
- Department of Biomedical Sciences, BK21 Plus Research Center for Biomedical Sciences, Ajou University Graduate School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea
| | - Oak-Sung Choo
- Department of Otolaryngology, Ajou University School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea.,Department of Medical Sciences, Ajou University Graduate School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea
| | - You-Sun Kim
- Department of Biomedical Sciences, BK21 Plus Research Center for Biomedical Sciences, Ajou University Graduate School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea
| | - Yun-Hoon Choung
- Department of Otolaryngology, Ajou University School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea.,Department of Biomedical Sciences, BK21 Plus Research Center for Biomedical Sciences, Ajou University Graduate School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea.,Department of Medical Sciences, Ajou University Graduate School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 16499, Republic of Korea
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Liu J, Wang H, Gu J, Deng T, Yuan Z, Hu B, Xu Y, Yan Y, Zan J, Liao M, DiCaprio E, Li J, Su S, Zhou J. BECN1-dependent CASP2 incomplete autophagy induction by binding to rabies virus phosphoprotein. Autophagy 2017; 13:739-753. [PMID: 28129024 PMCID: PMC5388250 DOI: 10.1080/15548627.2017.1280220] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Autophagy is an essential component of host immunity and used by viruses for survival. However, the autophagy signaling pathways involved in virus replication are poorly documented. Here, we observed that rabies virus (RABV) infection triggered intracellular autophagosome accumulation and results in incomplete autophagy by inhibiting autophagy flux. Subsequently, we found that RABV infection induced the reduction of CASP2/caspase 2 and the activation of AMP-activated protein kinase (AMPK)-AKT-MTOR (mechanistic target of rapamycin) and AMPK-MAPK (mitogen-activated protein kinase) pathways. Further investigation revealed that BECN1/Beclin 1 binding to viral phosphoprotein (P) induced an incomplete autophagy via activating the pathways CASP2-AMPK-AKT-MTOR and CASP2-AMPK-MAPK by decreasing CASP2. Taken together, our data first reveals a crosstalk of BECN1 and CASP2-dependent autophagy pathways by RABV infection.
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Affiliation(s)
- Juan Liu
- a Key Laboratory of Animal Virology of Ministry of Agriculture , Zhejiang University , Hangzhou , China
| | - Hailong Wang
- a Key Laboratory of Animal Virology of Ministry of Agriculture , Zhejiang University , Hangzhou , China
| | - Jinyan Gu
- b Institute of Immunology and College of Veterinary Medicine, Nanjing Agricultural University , Nanjing , China
| | - Tingjuan Deng
- a Key Laboratory of Animal Virology of Ministry of Agriculture , Zhejiang University , Hangzhou , China
| | - Zhuangchuan Yuan
- a Key Laboratory of Animal Virology of Ministry of Agriculture , Zhejiang University , Hangzhou , China
| | - Boli Hu
- b Institute of Immunology and College of Veterinary Medicine, Nanjing Agricultural University , Nanjing , China
| | - Yunbin Xu
- a Key Laboratory of Animal Virology of Ministry of Agriculture , Zhejiang University , Hangzhou , China
| | - Yan Yan
- a Key Laboratory of Animal Virology of Ministry of Agriculture , Zhejiang University , Hangzhou , China.,c Collaborative Innovation Center and State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, Zhejiang University , Hangzhou , China
| | - Jie Zan
- a Key Laboratory of Animal Virology of Ministry of Agriculture , Zhejiang University , Hangzhou , China
| | - Min Liao
- a Key Laboratory of Animal Virology of Ministry of Agriculture , Zhejiang University , Hangzhou , China.,c Collaborative Innovation Center and State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, Zhejiang University , Hangzhou , China
| | - Erin DiCaprio
- d Department of Veterinary Biosciences , College of Veterinary Medicine, Ohio State University , Columbus , OH , USA
| | - Jianrong Li
- d Department of Veterinary Biosciences , College of Veterinary Medicine, Ohio State University , Columbus , OH , USA
| | - Shuo Su
- b Institute of Immunology and College of Veterinary Medicine, Nanjing Agricultural University , Nanjing , China
| | - Jiyong Zhou
- a Key Laboratory of Animal Virology of Ministry of Agriculture , Zhejiang University , Hangzhou , China.,c Collaborative Innovation Center and State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, Zhejiang University , Hangzhou , China
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Coulon PG, Richetta C, Rouers A, Blanchet FP, Urrutia A, Guerbois M, Piguet V, Theodorou I, Bet A, Schwartz O, Tangy F, Graff-Dubois S, Cardinaud S, Moris A. HIV-Infected Dendritic Cells Present Endogenous MHC Class II-Restricted Antigens to HIV-Specific CD4+ T Cells. THE JOURNAL OF IMMUNOLOGY 2016; 197:517-32. [PMID: 27288536 DOI: 10.4049/jimmunol.1600286] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 05/17/2016] [Indexed: 01/07/2023]
Abstract
It is widely assumed that CD4(+) T cells recognize antigenic peptides (epitopes) derived solely from incoming, exogenous, viral particles or proteins. However, alternative sources of MHC class II (MHC-II)-restricted Ags have been described, in particular epitopes derived from newly synthesized proteins (so-called endogenous). In this study, we show that HIV-infected dendritic cells (DC) present MHC-II-restricted endogenous viral Ags to HIV-specific (HS) CD4(+) T cells. This endogenous pathway functions independently of the exogenous route for HIV Ag presentation and offers a distinct possibility for the immune system to activate HS CD4(+) T cells. We examined the implication of autophagy, which plays a crucial role in endogenous viral Ag presentation and thymic selection of CD4(+) T cells, in HIV endogenous presentation. We show that infected DC do not use autophagy to process MHC-II-restricted HIV Ags. This is unlikely to correspond to a viral escape from autophagic degradation, as infecting DC with Nef- or Env-deficient HIV strains did not impact HS T cell activation. However, we demonstrate that, in DC, specific targeting of HIV Ags to autophagosomes using a microtubule-associated protein L chain 3 (LC3) fusion protein effectively enhances and broadens HS CD4(+) T cell responses, thus favoring an endogenous MHC-II-restricted presentation. In summary, in DC, multiple endogenous presentation pathways lead to the activation of HS CD4(+) T cell responses. These findings will help in designing novel strategies to activate HS CD4(+) T cells that are required for CTL activation/maintenance and B cell maturation.
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Affiliation(s)
- Pierre-Grégoire Coulon
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Centre d'Immunologie et des Maladies Infectieuses, U1135, CNRS 8255, F-75013 Paris, France
| | - Clémence Richetta
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Centre d'Immunologie et des Maladies Infectieuses, U1135, CNRS 8255, F-75013 Paris, France
| | - Angéline Rouers
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Centre d'Immunologie et des Maladies Infectieuses, U1135, CNRS 8255, F-75013 Paris, France
| | - Fabien P Blanchet
- CNRS, FRE3689, Université de Montpellier, Centre d'Études d'Agents Pathogènes et Biotechnologies pour la Santé, 34293 Montpellier, France
| | - Alejandra Urrutia
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Centre d'Immunologie et des Maladies Infectieuses, U1135, CNRS 8255, F-75013 Paris, France
| | - Mathilde Guerbois
- Unité de Génomique Virale et Vaccination, Institut Pasteur, 75724 Paris, France
| | - Vincent Piguet
- Department of Dermatology and Wound Healing, Institute of Infection and Immunity, Cardiff University School of Medicine, Cardiff CF14 4XN, United Kingdom
| | - Ioannis Theodorou
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Centre d'Immunologie et des Maladies Infectieuses, U1135, CNRS 8255, F-75013 Paris, France; Département d'Immunologie, Assistance Publique-Hôpitaux de Paris, Hôpital Pitié-Salpêtrière, 75013 Paris, France; and
| | - Anne Bet
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Centre d'Immunologie et des Maladies Infectieuses, U1135, CNRS 8255, F-75013 Paris, France
| | | | - Frédéric Tangy
- Unité de Génomique Virale et Vaccination, Institut Pasteur, 75724 Paris, France
| | - Stéphanie Graff-Dubois
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Centre d'Immunologie et des Maladies Infectieuses, U1135, CNRS 8255, F-75013 Paris, France
| | - Sylvain Cardinaud
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Centre d'Immunologie et des Maladies Infectieuses, U1135, CNRS 8255, F-75013 Paris, France
| | - Arnaud Moris
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Centre d'Immunologie et des Maladies Infectieuses, U1135, CNRS 8255, F-75013 Paris, France; Département d'Immunologie, Assistance Publique-Hôpitaux de Paris, Hôpital Pitié-Salpêtrière, 75013 Paris, France; and
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25
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Lv S, Xu QY, Sun EC, Zhang JK, Wu DL. Dissection and integration of the autophagy signaling network initiated by bluetongue virus infection: crucial candidates ERK1/2, Akt and AMPK. Sci Rep 2016; 6:23130. [PMID: 26976147 PMCID: PMC4791558 DOI: 10.1038/srep23130] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 02/29/2016] [Indexed: 12/28/2022] Open
Abstract
Bluetongue virus (BTV), a complex double-stranded segmented RNA virus, has been found to initiate cellular autophagy for its own benefit. Here, with a view to understanding the underlying mechanisms, we first systematically dissected the exact signaling network in BTV-induced autophagy. We found that the activity of mTOR, a crucial pivot, was inhibited by BTV1 infection, subsequently leading to downstream p70S6K suppression and autophagy initiation. We then explored the upstream regulators of mTOR and analyzed their activities via a series of assays. We found BTV1-induced autophagy to be independent of the ERK1/2 signaling pathway. However, the BTV1-induced inhibition of PI3K/Akt was found to be partially responsible for mTOR inactivation and subsequent autophagy initiation. Furthermore, we found unexpectedly that AMPK seemed to play a more important role in BTV1-induced autophagy. Elevated [Ca2+]cyto-mediated activation of CaMKKβ exactly managed the activation of AMPK, which then positively regulated autophagy through suppressing mTOR. We must emphasize that TSC2 is a fatal mediator between upstream Akt or AMPK and downstream mTOR through its phosphorylation. Taken together, our data suggested that the BTV1-induced inhibition of the Akt-TSC2-mTOR pathway and the upregulation of the AMPK-TSC2-mTOR pathway both contributed to autophagy initiation and further favored virus replication.
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Affiliation(s)
- Shuang Lv
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Qing-Yuan Xu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - En-Cheng Sun
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Ji-Kai Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Dong-Lai Wu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
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26
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Jiang LB, Cao L, Yin XF, Yasen M, Yishake M, Dong J, Li XL. Activation of autophagy via Ca(2+)-dependent AMPK/mTOR pathway in rat notochordal cells is a cellular adaptation under hyperosmotic stress. Cell Cycle 2015; 14:867-79. [PMID: 25590373 DOI: 10.1080/15384101.2015.1004946] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Nucleus pulposus (NP) cells experience hyperosmotic stress in spinal discs; however, how these cells can survive in the hostile microenvironment remains unclear. Autophagy has been suggested to maintain cellular homeostasis under different stresses by degrading the cytoplasmic proteins and organelles. Here, we explored whether autophagy is a cellular adaptation in rat notochordal cells under hyperosmotic stress. Hyperosmotic stress was found to activate autophagy in a dose- and time-dependent manner. SQSTM1/P62 expression was decreased as the autophagy level increased. Transient Ca(2+) influx from intracellular stores and extracellular space was stimulated by hyperosmotic stress. Activation of AMPK and inhibition of p70S6K were observed under hyperosmotic conditions. However, intercellular Ca(2+) chelation inhibited the increase of LC3-II and partly reversed the decrease of p70S6K. Hyperosmotic stress decreased cell viability and promoted apoptosis. Inhibition of autophagy led to SQSTM1/P62 accumulation, reduced cell viability, and accelerated apoptosis in notochordal cells under this condition. These evidences suggest that autophagy induction via the Ca(2+)-dependent AMPK/mTOR pathway might occur as an adaptation mechanism for notochordal cells under hyperosmotic stress. Thus, activating autophagy might be a promising approach to improve viability of notochordal cells in intervertebral discs.
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Key Words
- AMPK, AMP activated Protein Kinase
- Adaptation
- Apoptosis
- Autophagy
- BAPTA-AM, bis-(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid, tetra(acetoxymethyl) ester
- DAPI, 4′, 6-diamidino-2-phenylindole
- ECM, extracellular matrix
- EGTA, ethyleneglycol-bis (2-aminoethylether)-N,N,N′, N-tetraacetic acid
- FITC, fluorescein isothiocyanate
- Hyperosmotic stress
- IDD, Intervertebral disc degeneration
- JC-1, 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolyl-carbocyanine iodide
- MAPK, mitogen-activated protein kinase
- MDC, Monodansylcadaverine
- MMP, mitochondrial membrane potential
- MPT, mitochondrial permeability transition
- NP, nucleus pulposus
- Notochordal cells
- OD, optical density
- PI, propidium iodide
- PLC, phospholipase C
- SQSTM1, Sequestosome-1
- TRPV4, Transient receptor potential vanilloid 4
- fluo3-AM, fluo3 acetoximethylester
- mTOR, mammalian target of rapamycin
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Affiliation(s)
- Li-Bo Jiang
- a Department of Orthopedic Surgery; Zhongshan Hospital ; Fudan University ; Shanghai , China
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Xiong Y, Yepuri G, Forbiteh M, Yu Y, Montani JP, Yang Z, Ming XF. ARG2 impairs endothelial autophagy through regulation of MTOR and PRKAA/AMPK signaling in advanced atherosclerosis. Autophagy 2015; 10:2223-38. [PMID: 25484082 PMCID: PMC4502672 DOI: 10.4161/15548627.2014.981789] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Impaired autophagy function and enhanced ARG2 (arginase 2)-MTOR (mechanistic target of rapamycin) crosstalk are implicated in vascular aging and atherosclerosis. We are interested in the role of ARG2 and the potential underlying mechanism(s) in modulation of endothelial autophagy. Using human nonsenescent “young” and replicative senescent endothelial cells as well as Apolipoprotein E-deficient (apoe−/−Arg2+/+) and Arg2-deficient apoe−/− (apoe−/−arg2−/−) mice fed a high-fat diet for 10 wk as the atherosclerotic animal model, we show here that overexpression of ARG2 in the young cells suppresses endothelial autophagy with concomitant enhanced expression of RICTOR, the essential component of the MTORC2 complex, leading to activation of the AKT-MTORC1-RPS6KB1/S6K1 (ribosomal protein S6 kinase, 70kDa, polypeptide 1) cascade and inhibition of PRKAA/AMPK (protein kinase, AMP-activated, α catalytic subunit). Expression of an inactive ARG2 mutant (H160F) had the same effect. Moreover, silencing RPS6KB1 or expression of a constitutively active PRKAA prevented autophagy suppression by ARG2 or H160F. In senescent cells, enhanced ARG2-RICTOR-AKT-MTORC1-RPS6KB1 and decreased PRKAA signaling and autophagy were observed, which was reversed by silencing ARG2 but not by arginase inhibitors. In line with the above observations, genetic ablation of Arg2 in apoe−/− mice reduced RPS6KB1, enhanced PRKAA signaling and endothelial autophagy in aortas, which was associated with reduced atherosclerosis lesion formation. Taken together, the results demonstrate that ARG2 impairs endothelial autophagy independently of the L-arginine ureahydrolase activity through activation of RPS6KB1 and inhibition of PRKAA, which is implicated in atherogenesis.
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Key Words
- AKT/PKB, v-akt murine thymoma viral oncogene homolog 1
- ANOVA, analysis of variance
- AR, aortic roots
- ARG1, arginase 1
- ARG2, arginase 2
- ARGINASE
- Atg, autophagy-related
- BEC, S-12 bromoethyl-L-cystine-HCl
- BECN1, Beclin 1, autophagy-related
- Baf A1, bafilomycin A1
- CMV, cytomegalovirus
- EC, endothelial cell
- H160F, inactive mutant of mouse ARG2
- HAEC, human aortic endothelial cells
- HUVEC, human umbilical vein endothelial cells
- LC3, microtubule-associated protein 1 light chain 3
- LDL, low-density lipoprotein
- MTOR
- MTOR, mechanistic target of rapamycin
- NOS3/eNOS, nitric oxide synthase 3 (endothelial cell)
- PE, phosphatidylethanolamine
- PRKAA
- PRKAA/AMPK, protein kinase, AMP-activated, α catalytic subunit
- PtdIns3K, phosphatidylinositol 3-kinase
- RPS6, ribosomal protein S6
- RPS6KB1/S6K1, ribosomal protein S6 kinase, 70kDa, polypeptide 1
- SA-ß-gal, senescence-associated-β-gal
- SMC, smooth muscle cells
- SQSTM1/p62, sequestosome 1
- TP53/p53, tumor protein 53
- Three-MA, 3-methyladenine
- ULK1, unc-51 like autophagy activating kinase 1
- VWF, von Willebrand factor
- WT, wild type
- apoe−/−, Apolipoprotein E-deficient
- arg2−/−, arginase type II deficient
- atherosclerosis
- autophagy
- endothelial cells
- nor-NOHA, Nω-hydroxy-nor-Arginine
- senescence
- shRNA, short hairpin RNA
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Affiliation(s)
- Yuyan Xiong
- a Vascular Biology; Department of Medicine; Division of Physiology; Faculty of Science ; University of Fribourg ; Fribourg , Switzerland
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Kim HS, Tian L, Jung M, Choi SK, Sun Y, Kim H, Moon WK. Downregulation of Choline Kinase-Alpha Enhances Autophagy in Tamoxifen-Resistant Breast Cancer Cells. PLoS One 2015; 10:e0141110. [PMID: 26496360 PMCID: PMC4619766 DOI: 10.1371/journal.pone.0141110] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 09/30/2015] [Indexed: 01/04/2023] Open
Abstract
Choline kinase-α (Chk-α) and autophagy have gained much attention, as they relate to the drug-resistance of breast cancer. Here, we explored the potential connection between Chk-α and autophagy in the mechanisms driving to tamoxifen (TAM) resistance, in estrogen receptor positive (ER+) breast cancer cells (BCCs). Human BCC lines (MCF-7 and TAM-resistant MCF-7 (MCF-7/TAM) cells) were used. Chk-α expression and activity was suppressed by the transduction of shRNA (shChk-α) with lentivirus and treatment with CK37, a Chk-α inhibitor. MCF-7/TAM cells had higher Chk-α expression and phosphocholine levels than MCF-7 cells. A specific downregulation of Chk-α by the transduction of shChk-α exhibited a significant decrease in phosphocholine levels in MCF-7 and MCF-7/TAM cells. The autophagy-related protein, cleaved microtubule-associated protein light chain 3 (LC3) and autophagosome-like structures were significantly increased in shChk-α-transduced or CK37-treated MCF-7 and MCF-7/TAM cells. The downregulation of Chk-α attenuated the phosphorylation of AKT, ERK1/2, and mTOR in both MCF-7 and MCF-7/TAM cells. In MCF-7 cells, the downregulation of Chk-α resulted in an induction of autophagy, a decreased proliferation ability and an activation of caspase-3. In MCF-7/TAM cells, despite a significant decrease in proliferation ability and an increase in the percentage of cells in the G0/G1 phase of the cell cycle, the downregulation of Chk-α did not induced caspase-dependent cell death and further enhanced autophagy and G0/G1 phase arrest. An autophagy inhibitor, methyladenine (3-MA) induced death and attenuated the level of elevated LC3 in MCF-7/TAM cells. Elucidating the interplay between choline metabolism and autophagy will provide unique opportunities to identify new therapeutic targets and develop novel treatment strategies that preferentially target TAM-resistance.
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Affiliation(s)
- Hoe Suk Kim
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110–744, Korea
| | - Lianji Tian
- Department of Biomedical Science, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul 110–799, Korea
| | - Minji Jung
- Department of Biomedical Science, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul 110–799, Korea
| | - Sul Ki Choi
- Department of Biomedical Science, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul 110–799, Korea
| | - Yujin Sun
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110–744, Korea
| | - Hyeonjin Kim
- Department of Biomedical Science, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul 110–799, Korea
| | - Woo Kyung Moon
- Department of Biomedical Science, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul 110–799, Korea
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110–744, Korea
- * E-mail:
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Alayev A, Berger SM, Kramer MY, Schwartz NS, Holz MK. The combination of rapamycin and resveratrol blocks autophagy and induces apoptosis in breast cancer cells. J Cell Biochem 2015; 116:450-7. [PMID: 25336146 DOI: 10.1002/jcb.24997] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 10/13/2014] [Indexed: 12/16/2022]
Abstract
Hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) is a frequent event in breast cancer and current efforts are aimed at targeting the mTORC1 signaling pathway in combination with other targeted therapies. However, patients often develop drug resistance in part due to activation of the oncogenic Akt signaling and upregulation of autophagy, which protects cancer cells from apoptosis. In the present study we investigated the effects of combination therapy of rapamycin (an allosteric mTORC1 inhibitor) together with resveratrol (a phytoestrogen that inhibits autophagy). Our results show that combination of these drugs maintains inhibition of mTORC1 signaling, while preventing upregulation of Akt activation and autophagy, causing apoptosis. Additionally, this combination was effective in estrogen receptor positive and negative breast cancer cells, underscoring its versatility.
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Affiliation(s)
- Anya Alayev
- Department of Biology, Stern College for Women of Yeshiva University, New York, New York
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Pourpirali S, Valacca C, Merlo P, Rizza S, D’Amico S, Cecconi F. Prolonged Pseudohypoxia Targets Ambra1 mRNA to P-Bodies for Translational Repression. PLoS One 2015; 10:e0129750. [PMID: 26086269 PMCID: PMC4473010 DOI: 10.1371/journal.pone.0129750] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 05/12/2015] [Indexed: 01/30/2023] Open
Abstract
Hypoxia has been associated with several pathological conditions ranging from stroke to cancer. This condition results in the activation of autophagy, a cyto-protective response involving the formation of double-membraned structures, the autophagosomes, in the cytoplasm. In this study, we investigated the cellular mechanisms regulating the autophagy gene Ambra1, after exposure to a hypoxia mimetic, cobalt chloride (CoCl2). We observed that, upon CoCl2 administration, activation of the apoptotic machinery was concomitant with down-regulation of the pro-autophagic factor Ambra1, without affecting transcription. Additionally, co-treating the cells with the caspase inhibitor z-VAD-FMK did not restore Ambra1 protein levels, this implying the involvement of other regulatory mechanisms. Partial re-localization of Ambra1 mRNA to non-translating fractions and cytoplasmic P-bodies was further detected. Thus, in this pseudohypoxic context, Ambra1 mRNA translocation to P-bodies and translational suppression correlated with increased cell death.
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Affiliation(s)
| | - Cristina Valacca
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
| | | | - Salvatore Rizza
- Unit of Cell Stress and Survival, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Silvia D’Amico
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | - Francesco Cecconi
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
- Unit of Cell Stress and Survival, Danish Cancer Society Research Center, Copenhagen, Denmark
- * E-mail:
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Abnormal Glucose Metabolism in Alzheimer's Disease: Relation to Autophagy/Mitophagy and Therapeutic Approaches. Neurochem Res 2015; 40:2557-69. [PMID: 26077923 DOI: 10.1007/s11064-015-1631-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 05/09/2015] [Accepted: 05/29/2015] [Indexed: 12/19/2022]
Abstract
Diminished glucose metabolism accompanies many neurodegenerative diseases including Alzheimer's disease. An understanding of the relation of these metabolic changes to the disease will enable development of novel therapeutic strategies. Following a metabolic challenge, cells generally conserve energy to preserve viability. This requires activation of many cellular repair/regenerative processes such as mitophagy/autophagy and fusion/fission. These responses may diminish cell function in the long term. Prolonged fission induces mitophagy/autophagy which promotes repair but if prolonged progresses to mitochondrial degradation. Abnormal glucose metabolism alters protein signaling including the release of proteins from the mitochondria or migration of proteins from the cytosol to the mitochondria or nucleus. This overview provides an insight into the different mechanisms of autophagy/mitophagy and mitochondrial dynamics in response to the diminished metabolism that occurs with diseases, especially neurodegenerative diseases such as Alzheimer's disease. The review discusses multiple aspects of mitochondrial responses including different signaling proteins and pathways of mitophagy and mitochondrial biogenesis. Improving cellular bioenergetics and mitochondrial dynamics will alter protein signaling and improve cellular/mitochondrial repair and regeneration. An understanding of these changes will suggest new therapeutic strategies.
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Zhang D, Tang B, Xie X, Xiao YF, Yang SM, Zhang JW. The interplay between DNA repair and autophagy in cancer therapy. Cancer Biol Ther 2015; 16:1005-13. [PMID: 25985143 DOI: 10.1080/15384047.2015.1046022] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
DNA is the prime target of anticancer treatments. DNA damage triggers a series of signaling cascades promoting cellular survival, including DNA repair, cell cycle arrest, and autophagy. The elevated basal and/or stressful levels of both DNA repair and autophagy observed in tumor cells, in contrast to normal cells, have been identified as the most important drug-responsive programs that impact the outcome of anticancer therapy. The exact relationship between DNA repair and autophagy in cancer cells remains unclear. On one hand, autophagy has been shown to regulate some of the DNA repair proteins after DNA damage by maintaining the balance between their synthesis, stabilization, and degradation. One the other hand, some evidence has demonstrated that some DNA repair molecular have a crucial role in the initiation of autophagy. In this review, we mainly discuss the interplay between DNA repair and autophagy in anticancer therapy and expect to enlighten some effective strategies for cancer treatment.
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Key Words
- AMPK, adenosine monophosphate-activated protein kinase
- ATG5, autophagy-related gene 5
- ATM, ataxia-telangiectasia mutated
- ATR, ATM and Rad3-related
- BER, base excision repair
- Chk1, check-point kinase 1
- Chk2, check-point kinase 2
- DDR, DNA damage response
- DNA damage
- DNA damage response
- DNA repair
- DNA-PKcs, DNA-dependent protein kinase catalytic subunit
- DSBs, double-strand breaks
- HDAC, histone deacetylases
- HR, homologous recombination
- IR, ionizing radiation
- MGMT, O6 methylguanine –DNA methyltransferase
- MMR, mismatch repair
- MRN, Mre11-Rad50-Nbs1
- NER, nucleotide excision recombination
- NHEJ, non-homologous end joining
- OGG1, 8-oxoguannine DNA glycosidase
- PARP-1, poly (ADP-ribose) polymerase 1
- PI3K, phosphoinositide 3-kinase
- PML, promyelocytic leukemia
- SSBs, single-strand break
- TMZ, temozolomide
- TSC2, tuberous sclerosis complex 2
- anticancer therapy
- apoptosis
- autophagy
- cell cycle arrest
- mTOR, mammalian target of rapamycin
- γ-H2AX, phosphorylated histone
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Affiliation(s)
- Dan Zhang
- a Department of Gastroenterology; Xinqiao Hospital; Third Military Medical University ; Chongqing , China
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Abstract
Cellular apoptosis is of major importance in the struggle between virus and host. Although many viruses use various strategies to control the cell death machinery by encoding anti-apoptotic virulence factors, it is now becoming clear that, in addition to their role in inhibiting apoptosis, these factors function in multiple immune and metabolic pathways to promote fitness and pathogenesis. In this Progress article, we discuss novel functions of viral anti-apoptotic factors in the regulation of autophagy, in the nuclear factor-κB (NF-κB) pathway and in interferon signalling, with a focus on persistent and oncogenic gammaherpesviruses. If viral anti-apoptotic proteins are to be properly exploited as targets for antiviral drugs, their diverse and complex roles should be considered.
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Affiliation(s)
- Chengyu Liang
- Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles, California 90033, USA
| | - Byung-Ha Oh
- Department of Biological Sciences, KAIST Institute for the Biocentury, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Jae U Jung
- Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles, California 90033, USA
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Archer T, Garcia D. Exercise and Dietary Restriction for Promotion of Neurohealth Benefits. Health (London) 2015. [DOI: 10.4236/health.2015.71016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Jiang L, Yuan F, Yin X, Dong J. Responses and adaptations of intervertebral disc cells to microenvironmental stress: a possible central role of autophagy in the adaptive mechanism. Connect Tissue Res 2014; 55:311-21. [PMID: 25000273 DOI: 10.3109/03008207.2014.942419] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Intervertebral discs comprise the largest avascular cartilaginous organ in the body, and its nutrient condition can be impaired by degeneration, aging and even metabolic disease. The unique microenvironment brings special stresses to various disc cell types, including nucleus pulposus cells, notochordal cells, annulus fibrosus cells and endplate chondrocytes. These cells experience nutrient starvation, acidic stress, hypoxic stress, hyperglycemic stress, osmotic stress and mechanical stress. Understanding the detailed responses and complex adaptive mechanisms of disc cells to various stresses might provide some clues to guide therapy for disc degeneration. By reviewing the published literatures describing disc cells under different hostile microenvironments, we conclude that these cells exhibit different responses to microenvironmental stresses with different mechanisms. Moreover, the interaction and combination of these stresses create a complex environment that synergistically increase or decrease influences on disc cells, compared with the effects of a single stress. Interestingly, most of these stresses activate autophagy, a self-protective mechanism by which dysfunctional protein and organelles are degraded. It is becoming clear that autophagy facilitates the cellular adaptation to stresses and might play a central role in regulating the adaptation of disc cells under stress. Therefore, autophagy modulation might be a potential therapeutic method to treat disc degeneration.
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Affiliation(s)
- Libo Jiang
- Department of Orthopedic Surgery, Zhongshan Hospital, Fudan University , Shanghai , China
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Hughes T, Coffin RS, Lilley CE, Ponce R, Kaufman HL. Critical analysis of an oncolytic herpesvirus encoding granulocyte-macrophage colony stimulating factor for the treatment of malignant melanoma. Oncolytic Virother 2014; 3:11-20. [PMID: 27512660 PMCID: PMC4918360 DOI: 10.2147/ov.s36701] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Oncolytic viruses that selectively lyse tumor cells with minimal damage to normal cells are a new area of therapeutic development in oncology. An attenuated herpesvirus encoding the granulocyte-macrophage colony stimulating factor (GM-CSF), known as talimogene laherparepvec (T-VEC), has been identified as an attractive oncolytic virus for cancer therapy based on preclinical tumor studies and results from early-phase clinical trials and a large randomized Phase III study in melanoma. In this review, we discuss the basic biology of T-VEC, describe the role of GM-CSF as an immune adjuvant, summarize the preclinical data, and report the outcomes of published clinical trials using T-VEC. The emerging data suggest that T-VEC is a safe and potentially effective antitumor therapy in malignant melanoma and represents the first oncolytic virus to demonstrate therapeutic activity against human cancer in a randomized, controlled Phase III study.
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Affiliation(s)
- Tasha Hughes
- Departments of General Surgery and Immunology and Microbiology, Rush University Medical Center, Chicago IL, USA
| | - Robert S Coffin
- BioVex, Inc, a subsidiary of Amgen, Inc, Sherman Oaks, CA, USA
| | | | - Rafael Ponce
- BioVex, Inc, a subsidiary of Amgen, Inc, Sherman Oaks, CA, USA
| | - Howard L Kaufman
- Departments of General Surgery and Immunology and Microbiology, Rush University Medical Center, Chicago IL, USA
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Alayev A, Sun Y, Snyder RB, Berger SM, Yu JJ, Holz MK. Resveratrol prevents rapamycin-induced upregulation of autophagy and selectively induces apoptosis in TSC2-deficient cells. Cell Cycle 2013; 13:371-82. [PMID: 24304514 DOI: 10.4161/cc.27355] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway is hyperactivated in a variety of cancers and disorders, including lymphangioleiomyomatosis (LAM) and tuberous sclerosis complex (TSC), which are characterized by mutations in tumor suppressors TSC1 or TSC2. The concern with the use of mTORC1 inhibitors, such as rapamycin or its analogs (rapalogs), is that they cause upregulation of autophagy and suppress the negative feedback loop to Akt, which promotes cell survival, causing the therapy to be only partially effective, and relapse occurs upon cessation of treatment. In this study, we investigate the use of rapamycin in combination with resveratrol, a naturally occurring polyphenol, in TSC2-deficient cells. We tested whether such combination would prevent rapamycin-induced upregulation of autophagy and shift the cell fate toward apoptosis. We found that this combination treatment blocked rapamycin-induced upregulation of autophagy and restored inhibition of Akt. Interestingly, the combination of rapamycin and resveratrol selectively promoted apoptosis of TSC2-deficient cells. Thus, the addition of resveratrol to rapamycin treatment may be a promising option for selective and targeted therapy for diseases with TSC loss and mTORC1 hyperactivation.
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Affiliation(s)
- Anya Alayev
- Department of Biology; Stern College for Women of Yeshiva University; New York, NY USA
| | - Yang Sun
- Brigham and Women's Hospital and Harvard Medical School; Boston, MA USA
| | - Rose B Snyder
- Department of Biology; Stern College for Women of Yeshiva University; New York, NY USA
| | - Sara Malka Berger
- Department of Biology; Stern College for Women of Yeshiva University; New York, NY USA
| | - Jane J Yu
- Brigham and Women's Hospital and Harvard Medical School; Boston, MA USA
| | - Marina K Holz
- Department of Biology; Stern College for Women of Yeshiva University; New York, NY USA; Department of Molecular Pharmacology; Stern College for Women of Yeshiva University; New York, NY USA; Albert Einstein Cancer Center; Albert Einstein College of Medicine; Bronx, NY USA
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Macrophage autophagy in atherosclerosis. Mediators Inflamm 2013; 2013:584715. [PMID: 23401644 PMCID: PMC3563164 DOI: 10.1155/2013/584715] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Accepted: 12/27/2012] [Indexed: 12/14/2022] Open
Abstract
Macrophages play crucial roles in atherosclerotic immune responses. Recent investigation into macrophage autophagy (AP) in atherosclerosis has demonstrated a novel pathway through which these cells contribute to vascular inflammation.
AP is a cellular catabolic process involving the delivery of cytoplasmic contents to the lysosomal machinery for ultimate degradation and recycling. Basal levels of macrophage AP play an essential role in atheroprotection during early atherosclerosis. However, AP becomes dysfunctional in the more advanced stages of the pathology and its deficiency promotes vascular inflammation, oxidative stress, and plaque necrosis. In this paper, we will discuss the role of macrophages and AP in atherosclerosis and the emerging evidence demonstrating the contribution of macrophage AP to vascular pathology. Finally, we will discuss how AP could be targeted for therapeutic utility.
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Zhu B, Zhou Y, Xu F, Shuai J, Li X, Fang W. Porcine circovirus type 2 induces autophagy via the AMPK/ERK/TSC2/mTOR signaling pathway in PK-15 cells. J Virol 2012; 86:12003-12. [PMID: 22915817 PMCID: PMC3486458 DOI: 10.1128/jvi.01434-12] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 08/16/2012] [Indexed: 12/12/2022] Open
Abstract
Porcine circovirus type 2 (PCV2) uses autophagy machinery to enhance its replication in PK-15 cells. However, the underlying mechanisms are unknown. By the use of specific inhibitors, RNA interference, and coimmunoprecipitation, we show that PCV2 induces autophagy in PK-15 cells through a pathway involving the kinases AMP-activated protein kinase (AMPK) and extracellular signal-regulated kinase 1/2 (ERK1/2), the tumor suppressor protein TSC2, and the mammalian target of rapamycin (mTOR). AMPK and ERK1/2 positively regulate autophagy through negative control of the mTOR pathway by phosphorylating TSC2 in PCV2-infected PK-15 cells. Thus, PCV2 might induce autophagy via the AMPK/ERK/TSC2/mTOR signaling pathway in the host cells, representing a pivotal mechanism for PCV2 pathogenesis.
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Affiliation(s)
- Binglin Zhu
- Zhejiang University Institute of Preventive Veterinary Medicine, Zhejiang Province Key Laboratory of Preventive Veterinary Medicine, and Key Laboratory of Molecular Animal Nutrition of the Ministry of Education, Hangzhou, People's Republic of China
| | - Yingshan Zhou
- Zhejiang University Institute of Preventive Veterinary Medicine, Zhejiang Province Key Laboratory of Preventive Veterinary Medicine, and Key Laboratory of Molecular Animal Nutrition of the Ministry of Education, Hangzhou, People's Republic of China
| | - Fei Xu
- Zhejiang University Institute of Preventive Veterinary Medicine, Zhejiang Province Key Laboratory of Preventive Veterinary Medicine, and Key Laboratory of Molecular Animal Nutrition of the Ministry of Education, Hangzhou, People's Republic of China
| | - Jiangbing Shuai
- Zhejiang Entry-Exit Inspection and Quarantine Bureau, Hangzhou, People's Republic of China
| | - Xiaoliang Li
- Zhejiang University Institute of Preventive Veterinary Medicine, Zhejiang Province Key Laboratory of Preventive Veterinary Medicine, and Key Laboratory of Molecular Animal Nutrition of the Ministry of Education, Hangzhou, People's Republic of China
| | - Weihuan Fang
- Zhejiang University Institute of Preventive Veterinary Medicine, Zhejiang Province Key Laboratory of Preventive Veterinary Medicine, and Key Laboratory of Molecular Animal Nutrition of the Ministry of Education, Hangzhou, People's Republic of China
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The herpes simplex virus 1 Us11 protein inhibits autophagy through its interaction with the protein kinase PKR. J Virol 2012; 87:859-71. [PMID: 23115300 DOI: 10.1128/jvi.01158-12] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Autophagy is now known to be an essential component of host innate and adaptive immunity. Several herpesviruses have developed various strategies to evade this antiviral host defense. Herpes simplex virus 1 (HSV-1) blocks autophagy in fibroblasts and in neurons, and the ICP34.5 protein is important for the resistance of HSV-1 to autophagy because of its interaction with the autophagy machinery protein Beclin 1. ICP34.5 also counteracts the shutoff of protein synthesis mediated by the double-stranded RNA (dsRNA)-dependent protein kinase PKR by inhibiting phosphorylation of the eukaryotic translation initiation factor 2α (eIF2α) in the PKR/eIF2α signaling pathway. Us11 is a late gene product of HSV-1, which is also able to preclude the host shutoff by direct inhibition of PKR. In the present study, we unveil a previously uncharacterized function of Us11 by demonstrating its antiautophagic activity. We show that the expression of Us11 is able to block autophagy and autophagosome formation in both HeLa cells and fibroblasts. Furthermore, immediate-early expression of Us11 by an ICP34.5 deletion mutant virus is sufficient to render the cells resistant to PKR-induced and virus-induced autophagy. PKR expression and the PKR binding domain of Us11 are required for the antiautophagic activity of Us11. However, unlike ICP34.5, Us11 did not interact with Beclin 1. We suggest that the inhibition of autophagy observed in cells infected with HSV-1 results from the activity of not only ICP34.5 on Beclin 1 but also Us11 by direct interaction with PKR.
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Mitochondrial dynamics and mitophagy in the 6-hydroxydopamine preclinical model of Parkinson's disease. PARKINSONS DISEASE 2012; 2012:131058. [PMID: 22966477 PMCID: PMC3431121 DOI: 10.1155/2012/131058] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 07/18/2012] [Indexed: 11/17/2022]
Abstract
We discuss the participation of mitochondrial dynamics and autophagy in the 6-hydroxidopamine-induced Parkinson's disease model. The regulation of dynamic mitochondrial processes such as fusion, fission, and mitophagy has been shown to be an important mechanism controlling cellular fate. An imbalance in mitochondrial dynamics may contribute to both familial and sporadic neurodegenerative diseases including Parkinson's disease. With special attention we address the role of second messengers as the role of reactive oxygen species and the mitochondria as the headquarters of cell death. The role of molecular signaling pathways, for instance, the participation of Dynamin-related protein 1(Drp1), will also be addressed. Furthermore evidence demonstrates the therapeutic potential of small-molecule inhibitors of mitochondrial division in Parkinson's disease. For instance, pharmacological inhibition of Drp1, through treatment with the mitochondrial division inhibitor-1, results in the abrogation of mitochondrial fission and in a decrease of the number of autophagic cells. Deciphering the signaling cascades that underlie mitophagy triggered by 6-OHDA, as well as the mechanisms that determine the selectivity of this response, will help to better understand this process and may have impact on human treatment strategies of Parkinson's disease.
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Seto S, Tsujimura K, Koide Y. Coronin-1a inhibits autophagosome formation around Mycobacterium tuberculosis-containing phagosomes and assists mycobacterial survival in macrophages. Cell Microbiol 2012; 14:710-27. [PMID: 22256790 DOI: 10.1111/j.1462-5822.2012.01754.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Mycobacterium tuberculosis is an intracellular bacterium that can survive within macrophages. Such survival is potentially associated with Coronin-1a (Coro1a). We investigated the mechanism by which Coro1a promotes the survival of M. tuberculosis in macrophages and found that autophagy was involved in the inhibition of mycobacterial survival in Coro1a knock-down (KD) macrophages. Fluorescence microscopy and immunoblot analyses revealed that LC3, a representative autophagic protein, was recruited to M. tuberculosis-containing phagosomes in Coro1a KD macrophages. Thin-section electron microscopy demonstrated that bacilli were surrounded by the multiple membrane structures in Coro1a KD macrophages. The proportion of LC3-positive mycobacterial phagosomes colocalized with p62/SQSTM1, ubiquitin or LAMP1 increased in Coro1a KD macrophages during infection. These results demonstrate the formation of autophagosomes around M. tuberculosis in Coro1a KD macrophages. Phosphorylation of p38 mitogen-activated protein kinase (MAPK) was induced in response to M. tuberculosis infection in Coro1a KD macrophages, suggesting that Coro1a blocks the activation of the p38 MAPK pathway involved in autophagosome formation. LC3 recruitment to M. tuberculosis-containing phagosomes was also observed in Coro1a KD alveolar or bone marrow-derived macrophages. These results suggest that Coro1a inhibits autophagosome formation in alveolar macrophages, thereby facilitating M. tuberculosis survival within the lung.
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Affiliation(s)
- Shintaro Seto
- Department of Infectious Diseases, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192, Japan.
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Identification of an AAA ATPase VPS4B-dependent pathway that modulates epidermal growth factor receptor abundance and signaling during hypoxia. Mol Cell Biol 2012; 32:1124-38. [PMID: 22252323 DOI: 10.1128/mcb.06053-11] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
VPS4B, an AAA ATPase (ATPase associated with various cellular activities), participates in vesicular trafficking and autophagosome maturation in mammalian cells. In solid tumors, hypoxia is a common feature and an indicator of poor treatment outcome. Our studies demonstrate that exogenous or endogenous (assessed with anchorage-independent three-dimensional multicellular spheroid culture) hypoxia induces VPS4B downregulation by the ubiquitin-proteasome system. Inhibition of VPS4B function by short hairpin VPS4B (sh-VPS4B) or expression of dominant negative VPS4B(E235Q) promotes anchorage-independent breast cancer cell growth and resistance to gefitinib, U0126, and genotoxicity. Biochemically, hyperactivation of epidermal growth factor receptor (EGFR), a receptor tyrosine kinase essential for cell proliferation and survival, accompanied by increased EGFR accumulation and altered intracellular compartmentalization, is observed in cells with compromised VPS4B. Furthermore, enhanced FOS/JUN induction and AP-1 promoter activation are noted in EGF-treated cells with VPS4B knockdown. However, VPS4B depletion does not affect EGFRvIII stability or its associated signaling. An inverse correlation between VPS4B expression and EGFR abundance is observed in breast tumors, and high-grade or recurrent breast carcinomas exhibit lower VPS4B expression. Together, our findings highlight a potentially critical role of VPS4B downregulation or chronic-hypoxia-induced VPS4B degradation in promoting tumor progression, unveiling a nongenomic mechanism for EGFR overproduction in human breast cancer.
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The human cytomegalovirus protein TRS1 inhibits autophagy via its interaction with Beclin 1. J Virol 2011; 86:2571-84. [PMID: 22205736 DOI: 10.1128/jvi.05746-11] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Human cytomegalovirus modulates macroautophagy in two opposite directions. First, HCMV stimulates autophagy during the early stages of infection, as evident by an increase in the number of autophagosomes and a rise in the autophagic flux. This stimulation occurs independently of de novo viral protein synthesis since UV-inactivated HCMV recapitulates the stimulatory effect on macroautophagy. At later time points of infection, HCMV blocks autophagy (M. Chaumorcel, S. Souquere, G. Pierron, P. Codogno, and A. Esclatine, Autophagy 4:1-8, 2008) by a mechanism that requires de novo viral protein expression. Exploration of the mechanisms used by HCMV to block autophagy unveiled a robust increase of the cellular form of Bcl-2 expression. Although this protein has an anti-autophagy effect via its interaction with Beclin 1, it is not responsible for the inhibition induced by HCMV, probably because of its phosphorylation by c-Jun N-terminal kinase. Here we showed that the HCMV TRS1 protein blocks autophagosome biogenesis and that a TRS1 deletion mutant is defective in autophagy inhibition. TRS1 has previously been shown to neutralize the PKR antiviral effector molecule. Although phosphorylation of eIF2α by PKR has been described as a stimulatory signal to induce autophagy, the PKR-binding domain of TRS1 is dispensable to its inhibitory effect. Our results show that TRS1 interacts with Beclin 1 to inhibit autophagy. We mapped the interaction with Beclin 1 to the N-terminal region of TRS1, and we demonstrated that the Beclin 1-binding domain of TRS1 is essential to inhibit autophagy.
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Ho K, Lin H, Ann DK, Chu PG, Yen Y. An overview of the rare parotid gland cancer. HEAD & NECK ONCOLOGY 2011; 3:40. [PMID: 21917153 PMCID: PMC3197557 DOI: 10.1186/1758-3284-3-40] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 09/14/2011] [Indexed: 12/05/2022]
Abstract
Cancer of the parotid gland is relatively rare, but carries poor prognosis owing to its prevailing distant metastases. In addition to the disease's basic epidemiology and pathology, we review some current discoveries of its tumorigenesis molecular mechanism. Based on published salivary gland cancer clinical trial data, non-surgical antitumor efficacies amongst a range of chemotherapy, radiation, and concurrent therapy regimens are compared. We also present the current development status of novel radiation therapy and targeted therapeutics, focusing on intensity-modulated radiation therapy (IMRT), and epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) blockages, which are showing promise for improving parotid gland cancer management.
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Affiliation(s)
- Kimberley Ho
- Department of Molecular Pharmacology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Helen Lin
- Department of Molecular Pharmacology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA 91010, USA
| | - David K Ann
- Department of Molecular Pharmacology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Peiguo G Chu
- Department of Pathology, City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Yun Yen
- Department of Molecular Pharmacology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA 91010, USA
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Abstract
Autophagy is an intracellular lysosomal (vacuolar) degradation process that is characterized by the formation of double-membrane vesicles, known as autophagosomes, which sequester cytoplasm. As autophagy is involved in cell growth, survival, development and death, the levels of autophagy must be properly regulated, as indicated by the fact that dysregulated autophagy has been linked to many human pathophysiologies, such as cancer, myopathies, neurodegeneration, heart and liver diseases, and gastrointestinal disorders. Substantial progress has recently been made in understanding the molecular mechanisms of the autophagy machinery, and in the regulation of autophagy. However, many unanswered questions remain, such as how the Atg1 complex is activated and the function of PtdIns3K is regulated, how the ubiquitin-like conjugation systems participate in autophagy and the mechanisms of phagophore expansion and autophagosome formation, how the network of TOR signaling pathways regulating autophagy are controlled, and what the underlying mechanisms are for the pro-cell survival and the pro-cell death effects of autophagy. As several recent reviews have comprehensively summarized the recent progress in the regulation of autophagy, we focus in this Commentary on the main unresolved questions in this field.
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Affiliation(s)
- Yongqiang Chen
- Life Sciences Institute and Department of Molecular, University of Michigan, Ann Arbor, MI 48109-2216, USA
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47
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Abstract
Macroautophagy (henceforth referred to as autophagy) is an in-bulk lysosomal degradative pathway that plays a crucial role in the maintenance of cellular homeostasis through the removal of damaged proteins and aged organelles. Following nutrient deprivation, a primary cellular response is the induction of autophagy that breaks down redundant cellular components and provides amino acids and additional precursor molecules for processes critical for cellular survival. In parallel, nutrient depletion leads to the mobilization of cellular lipid stores to supply free fatty acids for energy, thus pointing to regulatory and functional similarities between autophagy and lipid metabolism. The current chapter discusses the novel and mutually exclusive roles of autophagy in the regulation of lipid metabolism in the liver and of fat storage within the adipose tissue. Our studies in cultured hepatocytes and the murine liver have demonstrated that autophagy serves to degrade intracellular lipid stores through a process that we have termed "macrolipophagy" and that ablation of liver-specific autophagy leads to excessive hepatic lipid accumulation and the development of fatty liver. In contrast, preadipocytes in culture that lacked autophagy failed to differentiate into mature adipocytes and exhibited a reduction in fat storage that translated to decreased adipose tissue mass in an in vivo mouse model. These recent findings establish an association between autophagy and regulation of hepatic lipid metabolism and adipose tissue biology, thus providing new mechanistic insights into the regulation of these complex processes. These findings also highlight the possibility of novel therapeutic approaches, such as differential organ-specific regulation of autophagy to solve problems that arise from lipid over accumulation that occur in the metabolic syndrome and with aging.
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Balaburski GM, Hontz RD, Murphy ME. p53 and ARF: unexpected players in autophagy. Trends Cell Biol 2010; 20:363-9. [PMID: 20303758 DOI: 10.1016/j.tcb.2010.02.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 02/17/2010] [Accepted: 02/18/2010] [Indexed: 02/08/2023]
Abstract
p53 and ARF are well-established tumor-suppressor proteins that function together in the negative regulation of cancer. Recently, both proteins were found to play surprising roles in autophagy. Autophagy ('self-eating') is a crucial response of eukaryotic cells to metabolic and other stress. During this process, portions of the cytosol are sequestered into characteristic double-membrane vesicles that are delivered to the lysosome for degradation, leading to the release of free amino acids and promoting cell survival. The mechanisms whereby p53 and ARF control autophagy are only now becoming elucidated. An emerging question is whether we can develop metabolic poisons that preferentially destroy tumor cells depending on their reliance on autophagy for survival, and on their p53 and ARF status.
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Affiliation(s)
- Gregor M Balaburski
- Program in Molecular and Translational Medicine, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
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Herpesviruses and autophagy: catch me if you can! Viruses 2010; 2:314-333. [PMID: 21994613 PMCID: PMC3185561 DOI: 10.3390/v2010314] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 01/19/2010] [Accepted: 01/22/2010] [Indexed: 02/07/2023] Open
Abstract
Autophagy is an evolutionarily conserved cellular degradation pathway involving the digestion of intracellular components via the lysosomal pathway. The autophagic pathway constitutively maintains cellular homeostasis by recycling cytoplasmic organelles and proteins, but it is also stimulated by environmental stress conditions, such as starvation, oxidative stress, and the accumulation of misfolded proteins. It also acts as a cellular defense mechanism against microorganisms by contributing to both the innate and adaptive immunity, and by eliminating intracellular pathogens (xenophagy). There is growing evidence that host cells try to control Herpesvirus infections by activating the autophagic machinery. However, it is well-known that Herpesviruses are smart pathogens and several, such as HSV-1, HCMV and HHV-8, are known to have developed numerous defense strategies for evading the host’s immune response. Inhibition of the antiviral autophagic mechanism has also been reported. Autophagy has also been shown to enhance the major histocompatibility complex presentation of at least two viral proteins, the EBV-encoded EBNA-1 and the HSV-1 encoded gB. In this review, we present an overview of recent advances in our understanding of the complex interplay between autophagy and Herpesviruses.
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Abstract
BH3 domains were originally discovered in the context of apoptosis regulators and they mediate binding of proapoptotic Bcl-2 family members to antiapoptotic Bcl-2 family members. Yet, recent studies indicate that BH3 domains do not function uniquely in apoptosis regulation; they also function in the regulation of another critical pathway involved in cellular and tissue homeostasis called autophagy. Antiapoptotic Bcl-2 homologs downregulate autophagy through interactions with the essential autophagy effector and haploinsufficient tumor suppressor, Beclin 1. Beclin 1 contains a BH3 domain, similar to that of Bcl-2 proteins, which is necessary and sufficient for binding to antiapoptotic Bcl-2 homologs and required for Bcl-2-mediated inhibition of autophagy. This review will summarize the evidence that the BH3 domain of Beclin 1 serves as a key structural motif that enables Bcl-2 to function not only as an antiapoptotic protein, but also as an antiautophagy protein.
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Affiliation(s)
- S Sinha
- Department of Chemistry, Biochemistry and Molecular Biology, North Dakota State University, Fargo, ND, USA
| | - B Levine
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
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