1
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Yuan J, Zhang Q, Chen S, Yan M, Yue L. LC3-Associated Phagocytosis in Bacterial Infection. Pathogens 2022; 11:pathogens11080863. [PMID: 36014984 PMCID: PMC9415076 DOI: 10.3390/pathogens11080863] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 02/04/2023] Open
Abstract
LC3-associated phagocytosis (LAP) is a noncanonical autophagy process reported in recent years and is one of the effective mechanisms of host defense against bacterial infection. During LAP, bacteria are recognized by pattern recognition receptors (PRRs), enter the body, and then recruit LC3 onto a single-membrane phagosome to form a LAPosome. LC3 conjugation can promote the fusion of the LAPosomes with lysosomes, resulting in their maturation into phagolysosomes, which can effectively kill the identified pathogens. However, to survive in host cells, bacteria have also evolved strategies to evade killing by LAP. In this review, we summarized the mechanism of LAP in resistance to bacterial infection and the ways in which bacteria escape LAP. We aim to provide new clues for developing novel therapeutic strategies for bacterial infectious diseases.
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Affiliation(s)
- Jin Yuan
- Department of Pathogen Biology and Immunology, Faculty of Basic Medical Science, Kunming Medical University, Kunming 650500, China; (J.Y.); (Q.Z.); (S.C.)
| | - Qiuyu Zhang
- Department of Pathogen Biology and Immunology, Faculty of Basic Medical Science, Kunming Medical University, Kunming 650500, China; (J.Y.); (Q.Z.); (S.C.)
| | - Shihua Chen
- Department of Pathogen Biology and Immunology, Faculty of Basic Medical Science, Kunming Medical University, Kunming 650500, China; (J.Y.); (Q.Z.); (S.C.)
| | - Min Yan
- Department of Pathogen Biology and Immunology, Faculty of Basic Medical Science, Kunming Medical University, Kunming 650500, China; (J.Y.); (Q.Z.); (S.C.)
- Correspondence: (M.Y.); (L.Y.)
| | - Lei Yue
- The Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming 650118, China
- Correspondence: (M.Y.); (L.Y.)
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2
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Nuclear Receptors as Autophagy-Based Antimicrobial Therapeutics. Cells 2020; 9:cells9091979. [PMID: 32867365 PMCID: PMC7563212 DOI: 10.3390/cells9091979] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/21/2020] [Accepted: 08/26/2020] [Indexed: 12/13/2022] Open
Abstract
Autophagy is an intracellular process that targets intracellular pathogens for lysosomal degradation. Autophagy is tightly controlled at transcriptional and post-translational levels. Nuclear receptors (NRs) are a family of transcriptional factors that regulate the expression of gene sets involved in, for example, metabolic and immune homeostasis. Several NRs show promise as host-directed anti-infectives through the modulation of autophagy activities by their natural ligands or small molecules (agonists/antagonists). Here, we review the roles and mechanisms of NRs (vitamin D receptors, estrogen receptors, estrogen-related receptors, and peroxisome proliferator-activated receptors) in linking immunity and autophagy during infection. We also discuss the potential of emerging NRs (REV-ERBs, retinoic acid receptors, retinoic acid-related orphan receptors, liver X receptors, farnesoid X receptors, and thyroid hormone receptors) as candidate antimicrobials. The identification of novel roles and mechanisms for NRs will enable the development of autophagy-adjunctive therapeutics for emerging and re-emerging infectious diseases.
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3
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Liu Y, Jia Y, Yang K, Wang Z. Heterogeneous Strategies to Eliminate Intracellular Bacterial Pathogens. Front Microbiol 2020; 11:563. [PMID: 32390959 PMCID: PMC7192003 DOI: 10.3389/fmicb.2020.00563] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 03/16/2020] [Indexed: 12/21/2022] Open
Abstract
Antibiotic tolerance in bacterial pathogens that are genetically susceptible, but phenotypically tolerant to treatment, represents a growing crisis for public health. In particular, the intracellular bacteria-mediated antibiotic tolerance by acting as “Trojan horses” play a critical and underappreciated role in the disease burden of bacterial infections. Thus, more intense efforts are required to tackle this problem. In this review, we firstly provide a brief overview of modes of action of bacteria invasion and survival in macrophage or non-professional phagocytic cells. Furthermore, we summarize our current knowledge about promising strategies to eliminate these intracellular bacterial pathogens, including direct bactericidal agents, antibiotic delivery to infection sites by various carriers, and activation of host immune functions. Finally, we succinctly discuss the challenges faced by bringing them into clinical trials and our constructive perspectives.
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Affiliation(s)
- Yuan Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China.,Institute of Comparative Medicine, Yangzhou University, Yangzhou, China
| | - Yuqian Jia
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Kangni Yang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Zhiqiang Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
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4
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Streptolysin S induces mitochondrial damage and macrophage death through inhibiting degradation of glycogen synthase kinase-3β in Streptococcus pyogenes infection. Sci Rep 2019; 9:5371. [PMID: 30926881 PMCID: PMC6440947 DOI: 10.1038/s41598-019-41853-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 03/18/2019] [Indexed: 12/20/2022] Open
Abstract
Group A Streptococcus (GAS) infection is associated with a variety of human diseases. Previous studies indicate GAS infection leads to RAW264.7 cell death, but the mechanism is unclear. Here, analyzing the timing of reactive oxygen species (ROS) production and using mitochondrial ROS scavenger, we found the wild type GAS-induced RAW264.7 cell death was associated with mitochondrial ROS. The wild type GAS infection could activate glycogen synthase kinase-3β (GSK-3β). Inhibition of GSK-3β activity by lithium chloride or decreasing GSK-3β expression by lentivirus-mediated short hairpin RNA for GSK-3β could not only decrease the wild type GAS-induced mitochondrial ROS generation, mitochondria damage and cell death, but also reduced GAS intracellular replication. Streptolysin S (SLS), a GAS toxin, played the important role on GAS-induced macrophage death. Compared to the wild type GAS with its isogenic sagB mutant (SLS mutant)-infected macrophages, we found sagB mutant infection caused less mitochondrial ROS generation and cell death than those of the wild type GAS-infected ones. Furthermore, the sagB mutant, but not the wild type or the sagB-complementary mutant, could induce GSK-3β degradation via a proteasome-dependent pathway. These results suggest that a new mechanism of SLS-induced macrophage death was through inhibiting GSK-3β degradation and further enhancing mitochondrial damage.
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5
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Hsieh CL, Huang HM, Hsieh SY, Zheng PX, Lin YS, Chiang-Ni C, Tsai PJ, Wang SY, Liu CC, Wu JJ. NAD-Glycohydrolase Depletes Intracellular NAD + and Inhibits Acidification of Autophagosomes to Enhance Multiplication of Group A Streptococcus in Endothelial Cells. Front Microbiol 2018; 9:1733. [PMID: 30123194 PMCID: PMC6085451 DOI: 10.3389/fmicb.2018.01733] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 07/11/2018] [Indexed: 12/17/2022] Open
Abstract
Group A Streptococcus (GAS) is a human pathogen causing a wide spectrum of diseases, from mild pharyngitis to life-threatening necrotizing fasciitis. GAS has been shown to evade host immune killing by invading host cells. However, how GAS resists intracellular killing by endothelial cells is still unclear. In this study, we found that strains NZ131 and A20 have higher activities of NADase and intracellular multiplication than strain SF370 in human endothelial cells (HMEC-1). Moreover, nga mutants of NZ131 (SW957 and SW976) were generated to demonstrate that NADase activity is required for the intracellular growth of GAS in endothelial cells. We also found that intracellular levels of NAD+ and the NAD+/NADH ratio of NZ131-infected HMEC-1 cells were both lower than in cells infected by the nga mutant. Although both NZ131 and its nga mutant were trapped by LC3-positive vacuoles, only nga mutant vacuoles were highly co-localized with acidified lysosomes. On the other hand, intracellular multiplication of the nga mutant was increased by bafilomycin A1 treatment. These results indicate that NADase causes intracellular NAD+ imbalance and impairs acidification of autophagosomes to escape autophagocytic killing and enhance multiplication of GAS in endothelial cells.
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Affiliation(s)
- Cheng-Lu Hsieh
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Hsuan-Min Huang
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shu-Ying Hsieh
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Po-Xing Zheng
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
| | - Yee-Shin Lin
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chuan Chiang-Ni
- Department of Microbiology & Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Pei-Jane Tsai
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shu-Ying Wang
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Ching-Chuan Liu
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
- Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jiunn-Jong Wu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
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6
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Feng ZZ, Jiang AJ, Mao AW, Feng Y, Wang W, Li J, Zhang X, Xing K, Peng X. The Salmonella effectors SseF and SseG inhibit Rab1A-mediated autophagy to facilitate intracellular bacterial survival and replication. J Biol Chem 2018; 293:9662-9673. [PMID: 29610274 DOI: 10.1074/jbc.m117.811737] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 03/22/2018] [Indexed: 12/14/2022] Open
Abstract
In mammalian cells, autophagy plays crucial roles in restricting further spread of invading bacterial pathogens. Previous studies have established that the Salmonella virulence factors SseF and SseG are required for intracellular bacterial survival and replication. However, the underlying mechanism by which these two effectors facilitate bacterial infection remains elusive. Here, we report that SseF and SseG secreted by Salmonella Typhimurium (S. Typhimurium) inhibit autophagy in host cells and thereby establish a replicative niche for the bacteria in the cytosol. Mechanistically, SseF and SseG impaired autophagy initiation by directly interacting with the small GTPase Rab1A in the host cell. This interaction abolished Rab1A activation by disrupting the interaction with its guanine nucleotide exchange factor (GEF), the TRAPPIII (transport protein particle III) complex. This disruption of Rab1A signaling blocked the recruitment and activation of Unc-51-like autophagy-activating kinase 1 (ULK1) and decreased phosphatidylinositol 3-phosphate biogenesis, which ultimately impeded autophagosome formation. Furthermore, SseF- or SseG-deficient bacterial strains exhibited reduced survival and growth in both mammalian cell lines and mouse infection models, and Rab1A depletion could rescue these defects. These results reveal that virulence factor-dependent inactivation of the small GTPase Rab1A represents a previously unrecognized strategy of S Typhimurium to evade autophagy and the host defense system.
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Affiliation(s)
- Zhao-Zhong Feng
- From the School of Life Science, Jiangsu Normal University, Xuzhou 221116, China
| | - An-Jie Jiang
- From the School of Life Science, Jiangsu Normal University, Xuzhou 221116, China
| | - An-Wen Mao
- From the School of Life Science, Jiangsu Normal University, Xuzhou 221116, China
| | - Yuhan Feng
- From the School of Life Science, Jiangsu Normal University, Xuzhou 221116, China
| | - Weinan Wang
- From the School of Life Science, Jiangsu Normal University, Xuzhou 221116, China
| | - Jingjing Li
- From the School of Life Science, Jiangsu Normal University, Xuzhou 221116, China
| | - Xiaoyan Zhang
- From the School of Life Science, Jiangsu Normal University, Xuzhou 221116, China
| | - Ke Xing
- From the School of Life Science, Jiangsu Normal University, Xuzhou 221116, China
| | - Xue Peng
- From the School of Life Science, Jiangsu Normal University, Xuzhou 221116, China
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7
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Abstract
Group A Streptococcus (GAS) is a leading human bacterial pathogen with diverse clinical manifestations. Macrophages constitute a critical first line of host defense against GAS infection, using numerous surface and intracellular receptors such as Toll-like receptors and inflammasomes for pathogen recognition and activation of inflammatory signaling pathways. Depending on the intensity of the GAS infection, activation of these signaling cascades may provide a beneficial early alarm for effective immune clearance, or conversely, may cause hyperinflammation and tissue injury during severe invasive infection. Although traditionally considered an extracellular pathogen, GAS can invade and replicate within macrophages using specific molecular mechanisms to resist phagolysosomal and xenophagic killing. Unraveling GAS-macrophage encounters may reveal new treatment options for this leading agent of infection-associated mortality. [Formula: see text].
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Affiliation(s)
- J Andrés Valderrama
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Victor Nizet
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA.,Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
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8
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Salazar GA, Peñaloza HF, Pardo-Roa C, Schultz BM, Muñoz-Durango N, Gómez RS, Salazar FJ, Pizarro DP, Riedel CA, González PA, Alvarez-Lobos M, Kalergis AM, Bueno SM. Interleukin-10 Production by T and B Cells Is a Key Factor to Promote Systemic Salmonella enterica Serovar Typhimurium Infection in Mice. Front Immunol 2017; 8:889. [PMID: 28824622 PMCID: PMC5539121 DOI: 10.3389/fimmu.2017.00889] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 07/12/2017] [Indexed: 12/16/2022] Open
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) is a Gram-negative bacterium that produces disease in numerous hosts. In mice, oral inoculation is followed by intestinal colonization and subsequent systemic dissemination, which leads to severe pathogenesis without the activation of an efficient anti-Salmonella immune response. This feature suggests that the infection caused by S. Typhimurium may promote the production of anti-inflammatory molecules by the host that prevent efficient T cell activation and bacterial clearance. In this study, we describe the contribution of immune cells producing the anti-inflammatory cytokine interleukin-10 (IL-10) to the systemic infection caused by S. Typhimurium in mice. We observed that the production of IL-10 was required by S. Typhimurium to cause a systemic disease, since mice lacking IL-10 (IL-10-/-) were significantly more resistant to die after an infection as compared to wild-type (WT) mice. IL-10-/- mice had reduced bacterial loads in internal organs and increased levels of pro-inflammatory cytokines in serum at 5 days of infection. Importantly, WT mice showed high bacterial loads in tissues and no increase of cytokines in serum after 5 days of S. Typhimurium infection, except for IL-10. In WT mice, we observed a peak of il-10 messenger RNA production in ileum, spleen, and liver after 5 days of infection. Importantly, the adoptive transfer of T or B cells from WT mice restored the susceptibility of IL-10-/- mice to systemic S. Typhimurium infection, suggesting that the generation of regulatory cells in vivo is required to sustain a systemic infection by S. Typhimurium. These findings support the notion that IL-10 production from lymphoid cells is a key process in the infective cycle of S. Typhimurium in mice due to generation of a tolerogenic immune response that prevents bacterial clearance and supports systemic dissemination.
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Affiliation(s)
- Geraldyne A. Salazar
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de, Chile Santiago, Chile
| | - Hernán F. Peñaloza
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de, Chile Santiago, Chile
| | - Catalina Pardo-Roa
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de, Chile Santiago, Chile
| | - Bárbara M. Schultz
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de, Chile Santiago, Chile
| | - Natalia Muñoz-Durango
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de, Chile Santiago, Chile
| | - Roberto S. Gómez
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de, Chile Santiago, Chile
| | - Francisco J. Salazar
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de, Chile Santiago, Chile
| | - Daniela P. Pizarro
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de, Chile Santiago, Chile
| | - Claudia A. Riedel
- Millennium Institute on Immunology and Immunotherapy, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile
- Millennium Institute on Immunology and Immunotherapy, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas y Medicina, Universidad Andrés Bello, Santiago, Chile
| | - Pablo A. González
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de, Chile Santiago, Chile
| | - Manuel Alvarez-Lobos
- Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica de, Santiago, Chile
| | - Alexis M. Kalergis
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de, Chile Santiago, Chile
- Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Susan M. Bueno
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de, Chile Santiago, Chile
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9
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Nishiumi F, Ogawa M, Nakura Y, Hamada Y, Nakayama M, Mitobe J, Hiraide A, Sakai N, Takeuchi M, Yoshimori T, Yanagihara I. Intracellular fate of Ureaplasma parvum entrapped by host cellular autophagy. Microbiologyopen 2017; 6. [PMID: 28088841 PMCID: PMC5458467 DOI: 10.1002/mbo3.441] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 11/29/2016] [Accepted: 12/12/2016] [Indexed: 12/22/2022] Open
Abstract
Genital mycoplasmas, including Ureaplasma spp., are among the smallest human pathogenic bacteria and are associated with preterm birth. Electron microscopic observation of U. parvum showed that these prokaryotes have a regular, spherical shape with a mean diameter of 146 nm. U. parvum was internalized into HeLa cells by clathrin‐mediated endocytosis and survived for at least 14 days around the perinuclear region. Intracellular U. parvum reached endosomes in HeLa cells labeled with EEA1, Rab7, and LAMP‐1 within 1 to 3 hr. After 3 hr of infection, U. parvum induced the cytosolic accumulation of galectin‐3 and was subsequently entrapped by the autophagy marker LC3. However, when using atg7−/−MEF cells, autophagy was inadequate for the complete elimination of U. parvum in HeLa cells. U. parvum also colocalized with the recycling endosome marker Rab11. Furthermore, the exosomes purified from infected HeLa cell culture medium included U. parvum. In these purified exosomes ureaplasma lipoprotein multiple banded antigen, host cellular annexin A2, CD9, and CD63 were detected. This research has successfully shown that Ureaplasma spp. utilize the host cellular membrane compartments possibly to evade the host immune system.
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Affiliation(s)
- Fumiko Nishiumi
- Department of Developmental Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan
| | - Michinaga Ogawa
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Yukiko Nakura
- Department of Developmental Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan
| | - Yusuke Hamada
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Masahiro Nakayama
- Department of Pathology, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan
| | - Jiro Mitobe
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Atsushi Hiraide
- Critical Care Medical Center, Faculty of Medicine, Kindai University, Osaka, Japan
| | - Norio Sakai
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan.,Division of Health Science, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Makoto Takeuchi
- Department of Pathology, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan
| | - Tamotsu Yoshimori
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Itaru Yanagihara
- Department of Developmental Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan
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10
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Magraoui FE, Reidick C, Meyer HE, Platta HW. Autophagy-Related Deubiquitinating Enzymes Involved in Health and Disease. Cells 2015; 4:596-621. [PMID: 26445063 PMCID: PMC4695848 DOI: 10.3390/cells4040596] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/15/2015] [Accepted: 09/30/2015] [Indexed: 02/06/2023] Open
Abstract
Autophagy is an evolutionarily-conserved process that delivers diverse cytoplasmic components to the lysosomal compartment for either recycling or degradation. This involves the removal of protein aggregates, the turnover of organelles, as well as the elimination of intracellular pathogens. In this situation, when only specific cargoes should be targeted to the lysosome, the potential targets can be selectively marked by the attachment of ubiquitin in order to be recognized by autophagy-receptors. Ubiquitination plays a central role in this process, because it regulates early signaling events during the induction of autophagy and is also used as a degradation-tag on the potential autophagic cargo protein. Here, we review how the ubiquitin-dependent steps of autophagy are balanced or counteracted by deubiquitination events. Moreover, we highlight the functional role of the corresponding deubiquitinating enzymes and discuss how they might be involved in the occurrence of cancer, neurodegenerative diseases or infection with pathogenic bacteria.
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Affiliation(s)
- Fouzi El Magraoui
- Biomedizinische Forschung, Human Brain Proteomics II, Leibniz-Institut für Analytische Wissenschaften - ISAS -e.V. 44139 Dortmund, Germany.
| | - Christina Reidick
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany.
| | - Hemut E Meyer
- Biomedizinische Forschung, Human Brain Proteomics II, Leibniz-Institut für Analytische Wissenschaften - ISAS -e.V. 44139 Dortmund, Germany.
| | - Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, 44801 Bochum, Germany.
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11
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Yang H, Fu Q, Liu C, Li T, Wang Y, Zhang H, Lu X, Sang X, Zhong S, Huang J, Mao Y. Hepatitis B virus promotes autophagic degradation but not replication in autophagosome. Biosci Trends 2015; 9:111-6. [DOI: 10.5582/bst.2015.01049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Huayu Yang
- Department of Liver Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences
| | - Qining Fu
- Department of Vascular Surgery, the First Affiliated Hospital of Chongqing Medical University
- Department of Liver Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences
| | - Chen Liu
- Department of Liver Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences
| | - Taisheng Li
- Department of Infectious Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences
| | - Yanan Wang
- State Key Laboratory of Medical Molecular Biology, Department of Physiology, Institute of Basic Medical Sciences and School of Basic Medicine, Peking Union Medical College, Chinese Academy of Medical Sciences
| | - Hongbing Zhang
- State Key Laboratory of Medical Molecular Biology, Department of Physiology, Institute of Basic Medical Sciences and School of Basic Medicine, Peking Union Medical College, Chinese Academy of Medical Sciences
| | - Xin Lu
- Department of Liver Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences
| | - Xinting Sang
- Department of Liver Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences
| | - Shouxian Zhong
- Department of Liver Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences
| | - Jiefu Huang
- Department of Liver Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences
| | - Yilei Mao
- Department of Liver Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences
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12
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Cutting AS, Del Rosario Y, Mu R, Rodriguez A, Till A, Subramani S, Gottlieb RA, Doran KS. The role of autophagy during group B Streptococcus infection of blood-brain barrier endothelium. J Biol Chem 2014; 289:35711-23. [PMID: 25371213 DOI: 10.1074/jbc.m114.588657] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bacterial meningitis occurs when bloodborne pathogens invade and penetrate the blood-brain barrier (BBB), provoking inflammation and disease. Group B Streptococcus (GBS), the leading cause of neonatal meningitis, can enter human brain microvascular endothelial cells (hBMECs), but the host response to intracellular GBS has not been characterized. Here we sought to determine whether antibacterial autophagy, which involves selective recognition of intracellular organisms and their targeting to autophagosomes for degradation, is activated in BBB endothelium during bacterial infection. GBS infection resulted in increased punctate distribution of GFP-microtubule-associated protein 1 light chain 3 (LC3) and increased levels of endogenous LC3-II and p62 turnover, two hallmark indicators of active autophagic flux. Infection with GBS mutants revealed that bacterial invasion and the GBS pore-forming β-hemolysin/cytolysin (β-h/c) trigger autophagic activation. Cell-free bacterial extracts containing β-h/c activity induced LC3-II conversion, identifying this toxin as a principal provocative factor for autophagy activation. These results were confirmed in vivo using a mouse model of GBS meningitis as infection with WT GBS induced autophagy in brain tissue more frequently than a β-h/c-deficient mutant. Elimination of autophagy using Atg5-deficient fibroblasts or siRNA-mediated impairment of autophagy in hBMECs led to increased recovery of intracellular GBS. However, electron microscopy revealed that GBS was rarely found within double membrane autophagic structures even though we observed GBS-LC3 co-localization. These results suggest that although autophagy may act as a BBB cellular defense mechanism in response to invading and toxin-producing bacteria, GBS may actively thwart the autophagic pathway.
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Affiliation(s)
| | | | - Rong Mu
- From the Department of Biology and
| | | | - Andreas Till
- Division of Biological Sciences and San Diego Center for Systems Biology, University of California, San Diego, La Jolla, California 92093-0322, Stem Cell Pathologies Group, Life and Brain Center, University of Bonn, D-53127 Bonn, Germany, and
| | - Suresh Subramani
- Division of Biological Sciences and San Diego Center for Systems Biology, University of California, San Diego, La Jolla, California 92093-0322
| | - Roberta A Gottlieb
- Donald P. Shiley BioScience Center, San Diego State University, San Diego, California 92182
| | - Kelly S Doran
- From the Department of Biology and Department of Pediatrics, University of California San Diego School of Medicine, La Jolla, California 92093
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13
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Zemljic M, Pejkovic B, Krajnc I, Lipovsek S. Biological pathways involved in the development of inflammatory bowel disease. Wien Klin Wochenschr 2014; 126:626-33. [PMID: 25256178 DOI: 10.1007/s00508-014-0592-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 08/09/2014] [Indexed: 02/07/2023]
Abstract
Apoptosis, autophagy and necrosis are three distinct functional types of the mammalian cell death network. All of them are characterized by a number of cell's morphological changes. The inappropriate induction of cell death is involved in the pathogenesis of a number of diseases.Pathogenesis of inflammatory bowel diseases (ulcerative colitis, Crohn's disease) includes an abnormal immunological response to disturbed intestinal microflora. One of the most important reason in pathogenesis of chronic inflammatory disease and subsequent multiple organ pathology is a barrier function of the gut, regulating cellular viability. Recent findings have begun to explain the mechanisms by which intestinal epithelial cells are able to survive in such an environment and how loss of normal regulatory processes may lead to inflammatory bowel disease (IBD).This review focuses on the regulation of biological pathways in development and homeostasis in IBD. Better understanding of the physiological functions of biological pathways and their influence on inflammation, immunity, and barrier function will simplify our expertice of homeostasis in the gastrointestinal tract and in upgrading diagnosis and treatment.
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Affiliation(s)
- Mateja Zemljic
- Institute of Anatomy, Histology and Embryology, Faculty of Medicine, University of Maribor, Ljubljanska 5, 2000, Maribor, Slovenia,
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Li X, Guo G, Shen F, Kong L, Liang F, Sun G. Moxibustion Activates Macrophage Autophagy and Protects Experimental Mice against Bacterial Infection. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2014; 2014:450623. [PMID: 25140186 PMCID: PMC4129972 DOI: 10.1155/2014/450623] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 07/08/2014] [Indexed: 12/18/2022]
Abstract
Moxibustion is one of main therapies in traditional Chinese medicine and uses heat stimulation on the body surface from the burning of moxa to release pain or treat diseases. Emerging studies have shown that moxibustion can generate therapeutic effects by activating a series of signaling pathways and neuroendocrine-immune activities. Here we show moxibustion promoted profound macrophage autophagy in experimental Kunming mice, with reduced Akt phosphorylation and activated eIF2α phosphorylation. Consequently, moxibustion promoted bacterial clearance by macrophages and protected mice from mortality due to bacterial infection. These results indicate that moxibustion generates a protective response by activating autophagy against bacterial infections.
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Affiliation(s)
- Xiaojuan Li
- Acupuncture and Moxibustion College, Hubei University of Chinese Medicine, Wuhan, Hubei 430061, China
- Hubei Provincial Collaborative Innovation Center of Preventive Treatment by Acupuncture and Moxibustion, Wuhan, Hubei 430061, China
| | - Guanhua Guo
- Acupuncture and Moxibustion College, Hubei University of Chinese Medicine, Wuhan, Hubei 430061, China
- Shanxi University of Traditional Chinese Medicine, Taiyuan, Shanxi 030024, China
| | - Feng Shen
- Acupuncture and Moxibustion College, Hubei University of Chinese Medicine, Wuhan, Hubei 430061, China
| | - Lihong Kong
- Acupuncture and Moxibustion College, Hubei University of Chinese Medicine, Wuhan, Hubei 430061, China
| | - Fengxia Liang
- Acupuncture and Moxibustion College, Hubei University of Chinese Medicine, Wuhan, Hubei 430061, China
- Hubei Provincial Collaborative Innovation Center of Preventive Treatment by Acupuncture and Moxibustion, Wuhan, Hubei 430061, China
| | - Guojie Sun
- Acupuncture and Moxibustion College, Hubei University of Chinese Medicine, Wuhan, Hubei 430061, China
- Hubei Provincial Collaborative Innovation Center of Preventive Treatment by Acupuncture and Moxibustion, Wuhan, Hubei 430061, China
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15
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The globally disseminated M1T1 clone of group A Streptococcus evades autophagy for intracellular replication. Cell Host Microbe 2014; 14:675-82. [PMID: 24331465 DOI: 10.1016/j.chom.2013.11.003] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 10/10/2013] [Accepted: 10/28/2013] [Indexed: 01/03/2023]
Abstract
Autophagy is reported to be an important innate immune defense against the intracellular bacterial pathogen Group A Streptococcus (GAS). However, the GAS strains examined to date belong to serotypes infrequently associated with human disease. We find that the globally disseminated serotype M1T1 clone of GAS can evade autophagy and replicate efficiently in the cytosol of infected cells. Cytosolic M1T1 GAS (strain 5448), but not M6 GAS (strain JRS4), avoids ubiquitylation and recognition by the host autophagy marker LC3 and ubiquitin-LC3 adaptor proteins NDP52, p62, and NBR1. Expression of SpeB, a streptococcal cysteine protease, is critical for this process, as an isogenic M1T1 ΔspeB mutant is targeted to autophagy and attenuated for intracellular replication. SpeB degrades p62, NDP52, and NBR1 in vitro and within the host cell cytosol. These results uncover a proteolytic mechanism utilized by GAS to escape the host autophagy pathway that may underpin the success of the M1T1 clone.
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16
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Hu X, Yu J, Zhou X, Li Z, Xia Y, Luo Z, Wu Y. Synergism between upregulation of Rab7 and inhibition of autophagic degradation caused by mycoplasma facilitates intracellular mycoplasma infection. Mol Med Rep 2014; 9:793-800. [PMID: 24452847 PMCID: PMC3926517 DOI: 10.3892/mmr.2014.1907] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 01/10/2014] [Indexed: 12/22/2022] Open
Abstract
Following fusion of a mycoplasma with a host cell membrane, the inserted components of mycoplasma may then be transported through the endocytic pathway. However, the effects of mycoplasmas on the host cell endomembrane system are largely unknown. In this study, mycoplasma-induced changes in the dynamics of endocytic and autophagic systems were investigated. Endocytosis and autophagy are two major processes involved in the survival of intracellular prokaryotic pathogens. It was found that, immediately following infection, mycoplasmas induce endocytosis in the host cell; however, in the long term the mycoplasmas suppress turnover of the components of the endocytic pathway. Immunofluorescence microscopy revealed that Rab7 and LC3-II are recruited to the intracellular mycoplasma-containing compartments. Western blot analysis and quantitative reverse transcription-polymerase chain reaction (qPCR) showed that mycoplasmas increase expression of Rab7 by upregulating transcription, but increase levels of LC3-II and p62 by post-translational regulation. Furthermore, it was demonstrated that mycoplasma infection causes inhibition of autophagic degradation of LC3-II and p62. In addition, it was found that upregulation of Rab7 and inhibition of autophagic degradation synergistically contributes to intracellular mycoplasma accumulation. In conclusion, these findings suggest that mycoplasmas may manipulate host cell endosomal and autophagic systems in order to facilitate intracellular infection.
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Affiliation(s)
- Xiaopeng Hu
- Department of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Jie Yu
- First People's Hospital of Jiujiang City, Jiujiang, Jiangxi 330300, P.R. China
| | - Xiang Zhou
- The Fifth Hospital of Huangshi City, Huangshi, Hubei 435004, P.R. China
| | - Zhaoming Li
- Department of Oncology, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Yun Xia
- Department of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Zhiyong Luo
- Department of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Yaqun Wu
- Department of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
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17
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Junkins RD, Shen A, Rosen K, McCormick C, Lin TJ. Autophagy enhances bacterial clearance during P. aeruginosa lung infection. PLoS One 2013; 8:e72263. [PMID: 24015228 PMCID: PMC3756076 DOI: 10.1371/journal.pone.0072263] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 07/10/2013] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic bacterial pathogen which is the leading cause of morbidity and mortality among cystic fibrosis patients. Although P. aeruginosa is primarily considered an extacellular pathogen, recent reports have demonstrated that throughout the course of infection the bacterium acquires the ability to enter and reside within host cells. Normally intracellular pathogens are cleared through a process called autophagy which sequesters and degrades portions of the cytosol, including invading bacteria. However the role of autophagy in host defense against P. aeruginosa in vivo remains unknown. Understanding the role of autophagy during P. aeruginosa infection is of particular importance as mutations leading to cystic fibrosis have recently been shown to cause a blockade in the autophagy pathway, which could increase susceptibility to infection. Here we demonstrate that P. aeruginosa induces autophagy in mast cells, which have been recognized as sentinels in the host defense against bacterial infection. We further demonstrate that inhibition of autophagy through pharmacological means or protein knockdown inhibits clearance of intracellular P. aeruginosa in vitro, while pharmacologic induction of autophagy significantly increased bacterial clearance. Finally we find that pharmacological manipulation of autophagy in vivo effectively regulates bacterial clearance of P. aeruginosa from the lung. Together our results demonstrate that autophagy is required for an effective immune response against P. aeruginosa infection in vivo, and suggest that pharmacological interventions targeting the autophagy pathway could have considerable therapeutic potential in the treatment of P. aeruginosa lung infection.
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Affiliation(s)
- Robert D. Junkins
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Pediatrics, IWK Health Centre, Halifax, Nova Scotia, Canada
- Beatrice Hunter Cancer Research Institute, Halifax, Nova Scotia, Canada
| | - Ann Shen
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kirill Rosen
- Department of Biochemistry and Molecular Biology, Halifax, Nova Scotia, Canada
| | - Craig McCormick
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
- Beatrice Hunter Cancer Research Institute, Halifax, Nova Scotia, Canada
| | - Tong-Jun Lin
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Pediatrics, IWK Health Centre, Halifax, Nova Scotia, Canada
- Beatrice Hunter Cancer Research Institute, Halifax, Nova Scotia, Canada
- * E-mail:
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18
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Liu C, Ma H, Wu J, Huang Q, Liu JO, Yu L. Arginine68 is an essential residue for the C-terminal cleavage of human Atg8 family proteins. BMC Cell Biol 2013; 14:27. [PMID: 23721406 PMCID: PMC3686597 DOI: 10.1186/1471-2121-14-27] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 05/15/2013] [Indexed: 12/19/2022] Open
Abstract
Background Autophagy is a conserved cellular process that degrades and recycles cytoplasmic components via a lysosomal pathway. The phosphatidylethanolamine (PE)-conjugation of the Atg8 protein plays an important role in the yeast autophagy process. In humans, six Atg8 homologs, including MAP1LC3A, MAP1LC3B, MAP1LC3C (refer to LC3A, LC3B, and LC3C hereafter), GABARAP, GABARAPL1, and GABARAPL2 have been reported. All of them can be conjugated to PE through a ubiquitin-like conjugation system, and be located to autophagosomes. Results In this study, we found 3 new alternative splicing isoforms in LC3B, GABARAP, and GABARAPL1, (designated as LC3B-a, GABARAP-a and GABARAPL1-a, respectively). None of them can go through the PE-conjugation process and be located to autophagosomes. Interestingly, compared with LC3B, LC3B-a has a single amino acid (Arg68) deletion due to the NAGNAG alternative splicing in intron 3. Through structural simulations, we found that the C-terminal tail of LC3B-a is less mobile than that of LC3B, thus affecting its C-terminal cleavage by human ATG4 family proteins. Furthermore, we found that Arg68 is an essential residue facilitating the interaction between human Atg8 family proteins and ATG4B by forming a salt bridge with Asp171 of ATG4B. Depletion of this salt bridge reduces autophagosomes formation and autophagic flux under both normal and nutrition starvation conditions. Conclusions These results suggest Arg68 is an essential residue for the C-terminal cleavage of Atg8 family proteins during the autophagy process.
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Affiliation(s)
- Chao Liu
- State Key Laboratory of Genetic Engineering; Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, China
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19
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Osanai A, Li SJ, Asano K, Sashinami H, Hu DL, Nakane A. Fibronectin-binding protein, FbpA, is the adhesin responsible for pathogenesis ofListeria monocytogenesinfection. Microbiol Immunol 2013; 57:253-62. [DOI: 10.1111/1348-0421.12030] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 01/08/2013] [Accepted: 01/10/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Arihiro Osanai
- Department of Microbiology and Immunology; Hirosaki University Graduate School of Medicine; 5 Zaifu-cho, Hirosaki; Aomori; 036-8562; Japan
| | | | - Krisana Asano
- Department of Microbiology and Immunology; Hirosaki University Graduate School of Medicine; 5 Zaifu-cho, Hirosaki; Aomori; 036-8562; Japan
| | - Hiroshi Sashinami
- Department of Microbiology and Immunology; Hirosaki University Graduate School of Medicine; 5 Zaifu-cho, Hirosaki; Aomori; 036-8562; Japan
| | - Dong-Liang Hu
- Department of Microbiology and Immunology; Hirosaki University Graduate School of Medicine; 5 Zaifu-cho, Hirosaki; Aomori; 036-8562; Japan
| | - Akio Nakane
- Department of Microbiology and Immunology; Hirosaki University Graduate School of Medicine; 5 Zaifu-cho, Hirosaki; Aomori; 036-8562; Japan
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20
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Choi JH, Cheong TC, Ha NY, Ko Y, Cho CH, Jeon JH, So I, Kim IK, Choi MS, Kim IS, Cho NH. Orientia tsutsugamushi subverts dendritic cell functions by escaping from autophagy and impairing their migration. PLoS Negl Trop Dis 2013; 7:e1981. [PMID: 23301113 PMCID: PMC3536799 DOI: 10.1371/journal.pntd.0001981] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Accepted: 11/05/2012] [Indexed: 11/26/2022] Open
Abstract
Background Dendritic cells (DCs) are the most potent antigen-presenting cells that link innate and adaptive immune responses, playing a pivotal role in triggering antigen-specific immunity. Antigen uptake by DCs induces maturational changes that include increased surface expression of major histocompatibility complex (MHC) and costimulatory molecules. In addition, DCs actively migrate to regional lymph nodes and activate antigen-specific naive T cells after capturing antigens. We characterize the functional changes of DCs infected with Orientia tsutsugamushi, the causative agent of scrub typhus, since there is limited knowledge of the role played by DCs in O. tsutsugamushi infection. Methodology/Principal Finding O. tsutsugamushi efficiently infected bone marrow-derived DCs and induced surface expression of MHC II and costimulatory molecules. In addition, O. tsutsugamushi induced autophagy activation, but actively escaped from this innate defense system. Infected DCs also secreted cytokines and chemokines such as IL-6, IL-12, MCP5, MIP-1α, and RANTES. Furthermore, in vitro migration of DCs in the presence of a CCL19 gradient within a 3D collagen matrix was drastically impaired when infected with O. tsutsugamushi. The infected cells migrated much less efficiently into lymphatic vessels of ear dermis ex vivo when compared to LPS-stimulated DCs. In vivo migration of O. tsutsugamushi-infected DCs to regional lymph nodes was significantly impaired and similar to that of immature DCs. Finally, we found that MAP kinases involved in chemotactic signaling were differentially activated in O. tsutsugamushi-infected DCs. Conclusion/Significance These results suggest that O. tsutsugamushi can target DCs to exploit these sentinel cells as replication reservoirs and delay or impair the functional maturation of DCs during the bacterial infection in mammals. Scrub typhus is an acute febrile illness caused by Orientia tsutsugamushi infection and is one of the main causes of febrile illness in the Asia-Pacific region. If not properly treated with antibiotics, patients often develop severe vasculitis that affects multiple organs, and the mortality rate of untreated patients reaches up to 30%. To understand the pathogenic mechanisms of the infectious disease, we characterized the functional changes of O. tsutsugamushi–infected dendritic cells (DCs), which play a pivotal role in orchestrating innate and adaptive immune responses. The obligate intracellular bacteria efficiently infected bone marrow-derived DCs and activated the cells as measured by induced surface expression of MHC II and costimulatory molecules, secretion of cytokines and chemokines, and autophagy induction. However, the live bacteria actively escaped from host autophagosomes and the migration of infected cells was severely impaired in vitro, ex vivo, and in vivo infection models. Finally, we found that MAP kinases involved in chemotactic signaling were differentially activated in O. tsutsugamushi-infected DCs. These results suggest that O. tsutsugamushi can target DCs to exploit these sentinel cells as replication reservoirs and delay or impair the functional maturation of DCs during the bacterial infection in mammals.
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Affiliation(s)
- Ji-Hye Choi
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Taek-Chin Cheong
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Na-Young Ha
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Youngho Ko
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Chung-Hyun Cho
- Pharmacology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ju-Hong Jeon
- Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Insuk So
- Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - In-Kyu Kim
- Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Myung-Sik Choi
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ik-Sang Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Nam-Hyuk Cho
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Institute of Endemic Disease, Seoul National University Medical Research Center and Bundang Hospital, Jongno-Gu, Seoul, Republic of Korea
- * E-mail:
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21
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Mantegazza AR, Magalhaes JG, Amigorena S, Marks MS. Presentation of phagocytosed antigens by MHC class I and II. Traffic 2012; 14:135-52. [PMID: 23127154 DOI: 10.1111/tra.12026] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 11/01/2012] [Accepted: 11/06/2012] [Indexed: 12/15/2022]
Abstract
Phagocytosis provides innate immune cells with a mechanism to take up and destroy pathogenic bacteria, apoptotic cells and other large particles. In some cases, however, peptide antigens from these particles are preserved for presentation in association with major histocompatibility complex (MHC) class I or class II molecules in order to stimulate antigen-specific T cells. Processing and presentation of antigens from phagosomes presents a number of distinct challenges relative to antigens internalized by other means; while bacterial antigens were among the first discovered to be presented to T cells, analyses of the cellular mechanisms by which peptides from phagocytosed antigens assemble with MHC molecules and by which these complexes are then expressed at the plasma membrane have lagged behind those of conventional model soluble antigens. In this review, we cover recent advances in our understanding of these processes, including the unique cross-presentation of phagocytosed antigens by MHC class I molecules, and in their control by signaling modalities in phagocytic cells.
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Affiliation(s)
- Adriana R Mantegazza
- Department of Pathology & Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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22
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Tattoli I, Philpott DJ, Girardin SE. The bacterial and cellular determinants controlling the recruitment of mTOR to the Salmonella-containing vacuole. Biol Open 2012; 1:1215-25. [PMID: 23259056 PMCID: PMC3522883 DOI: 10.1242/bio.20122840] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 09/05/2012] [Indexed: 12/30/2022] Open
Abstract
Bacterial invasion results in the rapid induction of an acute state of cytosolic amino acid (AA) starvation, provoked by host membrane damage. Bacteria-induced AA starvation, in turn, down-regulates mTOR signaling while triggering autophagy and the integrated stress response pathway dependent on GCN2, eIF2α and ATF3. In Salmonella-infected cells, we now demonstrate that the host AA starvation response program depended on the Salmonella pathogenicity island (SPI)-1, the activity of which was required to damage the Salmonella-containing vacuole (SCV) in the early stage of infection. At a later stage (3–4 hour post-infection), the progressive recruitment of mTOR to the surface of the SCV appeared to be independent of the activity of SPI-2 and of SCV positioning in the cell. Instead, mTOR localization to the SCV required the activity of host AA transporters SLC1A5, SLC3A2 and SLC7A5, resulting in bacterial escape from autophagy. These results expand our understanding of the mechanisms underlying the AA starvation response in Salmonella-infected cells.
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Affiliation(s)
- Ivan Tattoli
- Department of Laboratory Medicine and Pathobiology, University of Toronto , Toronto, ON M6G 2T6 , Canada ; Department of Immunology, University of Toronto , Toronto, ON M6G 2T6 , Canada
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23
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Sun HS, Eng EWY, Jeganathan S, Sin ATW, Patel PC, Gracey E, Inman RD, Terebiznik MR, Harrison RE. Chlamydia trachomatis vacuole maturation in infected macrophages. J Leukoc Biol 2012; 92:815-27. [PMID: 22807527 DOI: 10.1189/jlb.0711336] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterium responsible for one of the most common sexually transmitted diseases. In epithelial cells, C. trachomatis resides in a modified membrane-bound vacuole known as an inclusion, which is isolated from the endocytic pathway. However, the maturation process of C. trachomatis within immune cells, such as macrophages, has not been studied extensively. Here, we demonstrated that RAW macrophages effectively suppressed C. trachomatis growth and prevented Golgi stack disruption, a hallmark defect in epithelial cells after C. trachomatis infection. Next, we systematically examined association between C. trachomatis and various endocytic pathway markers. Spinning disk confocal time-lapse studies revealed significant and rapid association between C. trachomatis with Rab7 and LAMP1, markers of late endosomes and lysosomes. Moreover, pretreatment with an inhibitor of lysosome acidification led to significant increases in C. trachomatis growth in macrophages. At later stages of infection, C. trachomatis associated with the autophagy marker LC3. TEM analysis confirmed that a significant portion of C. trachomatis resided within double-membrane-bound compartments, characteristic of autophagosomes. Together, these results suggest that macrophages can suppress C. trachomatis growth by targeting it rapidly to lysosomes; moreover, autophagy is activated at later stages of infection and targets significant numbers of the invading bacteria, which may enhance subsequent chlamydial antigen presentation.
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Affiliation(s)
- He Song Sun
- Departments of Cell and Systems Biology and Biological Sciences, University of Toronto Scarborough, Ontario, Canada
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24
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Campylobacter jejuni translocation across intestinal epithelial cells is facilitated by ganglioside-like lipooligosaccharide structures. Infect Immun 2012; 80:3307-18. [PMID: 22778098 DOI: 10.1128/iai.06270-11] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Translocation across intestinal epithelial cells is an established pathogenic feature of the zoonotic bacterial species Campylobacter jejuni. The number of C. jejuni virulence factors known to be involved in translocation is limited. In the present study, we investigated whether sialylation of C. jejuni lipooligosaccharide (LOS) structures, generating human nerve ganglioside mimics, is important for intestinal epithelial translocation. We here show that C. jejuni isolates expressing ganglioside-like LOS bound in larger numbers to the Caco-2 intestinal epithelial cells than C. jejuni isolates lacking such structures. Next, we found that ganglioside-like LOS facilitated endocytosis of bacteria into Caco-2 cells, as visualized by quantitative microscopy using the early and late endosomal markers early endosome-associated protein 1 (EEA1), Rab5, and lysosome-associated membrane protein 1 (LAMP-1). This increased endocytosis was associated with larger numbers of surviving and translocating bacteria. Next, we found that two different intestinal epithelial cell lines (Caco-2 and T84) responded with an elevated secretion of the T-cell attractant CXCL10 to infection by ganglioside-like LOS-expressing C. jejuni isolates. We conclude that C. jejuni translocation across Caco-2 cells is facilitated by ganglioside-like LOS, which is of clinical relevance since C. jejuni ganglioside-like LOS-expressing isolates are linked with severe gastroenteritis and bloody stools in C. jejuni-infected patients.
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Abstract
Autophagy is a housekeeping process that maintains cellular homeostasis through recycling of nutrients and degradation of damaged or aged cytoplasmic constituents. Over the past several years, accumulating evidence has suggested that autophagy can function as an intracellular innate defense pathway in response to infection with a variety of bacteria and viruses. Autophagy plays a role as a specialized immunologic effector and regulates innate immunity to exert antimicrobial defense mechanisms. Numerous bacterial pathogens have developed the ability to invade host cells or to subvert host autophagy to establish a persistent infection. In this review, we have summarized the recent advances in our understanding of the interaction between antibacterial autophagy (xenophagy) and different bacterial pathogens.
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Affiliation(s)
- Jae Min Yuk
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon 301-747, Korea
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Nair U, Yen WL, Mari M, Cao Y, Xie Z, Baba M, Reggiori F, Klionsky DJ. A role for Atg8-PE deconjugation in autophagosome biogenesis. Autophagy 2012; 8:780-93. [PMID: 22622160 DOI: 10.4161/auto.19385] [Citation(s) in RCA: 159] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Formation of the autophagosome is likely the most complex step of macroautophagy, and indeed it is the morphological and functional hallmark of this process; accordingly, it is critical to understand the corresponding molecular mechanism. Atg8 is the only known autophagy-related (Atg) protein required for autophagosome formation that remains associated with the completed sequestering vesicle. Approximately one-fourth of all of the characterized Atg proteins that participate in autophagosome biogenesis affect Atg8, regulating its conjugation to phosphatidylethanolamine (PE), localization to the phagophore assembly site and/or subsequent deconjugation. An unanswered question in the field regards the physiological role of the deconjugation of Atg8-PE. Using an Atg8 mutant that bypasses the initial Atg4-dependent processing, we demonstrate that Atg8 deconjugation is an important step required to facilitate multiple events during macroautophagy. The inability to deconjugate Atg8-PE results in the mislocalization of this protein to the vacuolar membrane. We also show that the deconjugation of Atg8-PE is required for efficient autophagosome biogenesis, the assembly of Atg9-containing tubulovesicular clusters into phagophores/autophagosomes, and for the disassembly of PAS-associated Atg components.
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Affiliation(s)
- Usha Nair
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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Kozarov E. Bacterial invasion of vascular cell types: vascular infectology and atherogenesis. Future Cardiol 2012; 8:123-38. [PMID: 22185451 DOI: 10.2217/fca.11.75] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
To portray the chronic inflammation in atherosclerosis, leukocytic cell types involved in the immune response to invading pathogens are often the focus. However, atherogenesis is a complex pathological deterioration of the arterial walls, where vascular cell types are participants with regards to deterioration and disease. Since other recent reviews have detailed the role of both the innate and adaptive immune response in atherosclerosis, herein we will summarize the latest developments regarding the association of bacteria with vascular cell types: infections as a risk factor for atherosclerosis; bacterial invasion of vascular cell types; the atherogenic sequelae of bacterial presence such as endothelial activation and blood clotting; and the identification of the species that are able to colonize this niche. The evidence of a polybacterial infectious component of the atheromatous lesions opens the doors for exploration of the new field of vascular infectology and for the study of atherosclerosis microbiome.
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Affiliation(s)
- Emil Kozarov
- Section of Oral & Diagnostic Sciences, Columbia University Medical Center, 630 West 168 Street, P&S Box 20, New York, NY 10032, USA.
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Three-Axis Model for Atg Recruitment in Autophagy against Salmonella. Int J Cell Biol 2012; 2012:389562. [PMID: 22505927 PMCID: PMC3299270 DOI: 10.1155/2012/389562] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 12/22/2011] [Indexed: 01/29/2023] Open
Abstract
Salmonella enterica serovar Typhimurium enter epithelial cells and take up residence there. Within epithelial cells, a portion of the bacteria are surrounded by an autophagosome-like double-membrane structure, and they are still residing within the Salmonella-containing vacuole (SCV). In this paper, we will discuss how the autophagy machinery is recruited in proximity to Salmonella. The formation of this double membrane requires Atg9L1 and FIP200; these proteins are important for autophagy-specific recruitment of the PI3-kinase complex. In the absence of Atg9L1, FIP200, and PI3-kinase activity, LC3 is still recruited to the vicinity of Salmonella. We propose a novel model in which the mechanism of LC3 recruitment is separate from the generation of the isolation membrane. There exist at least three axes in Atg recruitment: ULK1 complex, Atg9L1, and Atg16L complex.
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Anand PK, Tait SWG, Lamkanfi M, Amer AO, Nunez G, Pagès G, Pouysségur J, McGargill MA, Green DR, Kanneganti TD. TLR2 and RIP2 pathways mediate autophagy of Listeria monocytogenes via extracellular signal-regulated kinase (ERK) activation. J Biol Chem 2011; 286:42981-91. [PMID: 22033934 PMCID: PMC3234870 DOI: 10.1074/jbc.m111.310599] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Indexed: 01/14/2023] Open
Abstract
Listeria monocytogenes is a facultative intracellular pathogen that invades both phagocytic and non-phagocytic cells. Recent studies have shown that L. monocytogenes infection activates the autophagy pathway. However, the innate immune receptors involved and the downstream signaling pathways remain unknown. Here, we show that macrophages deficient in the TLR2 and NOD/RIP2 pathway display defective autophagy induction in response to L. monocytogenes. Inefficient autophagy in Tlr2(-/-) and Nod2(-/-) macrophages led to a defect in bacteria colocalization with the autophagosomal marker GFP-LC3. Consequently, macrophages lacking TLR2 and NOD2 were found to be more susceptible to L. monocytogenes infection, as were the Rip2(-/-) mice. Tlr2(-/-) and Nod2(-/-) cells showed perturbed NF-κB and ERK signaling. However, autophagy against L. monocytogenes was dependent selectively on the ERK pathway. In agreement, wild-type cells treated with a pharmacological inhibitor of ERK or ERK-deficient cells displayed inefficient autophagy activation in response to L. monocytogenes. Accordingly, fewer bacteria were targeted to the autophagosomes and, consequently, higher bacterial growth was observed in cells deficient in the ERK signaling pathway. These findings thus demonstrate that TLR2 and NOD proteins, acting via the downstream ERK pathway, are crucial to autophagy activation and provide a mechanistic link between innate immune receptors and induction of autophagy against cytoplasm-invading microbes, such as L. monocytogenes.
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Affiliation(s)
- Paras K. Anand
- From the From the Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Stephen W. G. Tait
- From the From the Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Mohamed Lamkanfi
- the Department of Biochemistry, Ghent University, 9000 Ghent, Belgium
- the Department of Medical Protein Research, Flanders Institute of Biotechnology, 9000 Ghent, Belgium
| | - Amal O. Amer
- the Department of Internal Medicine, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, and the Center for Microbial Interface Biology, Ohio State University, Columbus, Ohio 43210
| | - Gabriel Nunez
- the Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan 48109, and
| | - Gilles Pagès
- the Institute of Developmental Biology and Cancer Research, CNRS UMR 6543 Centre A, Lacassagne, 06189 Nice, France
| | - Jacques Pouysségur
- the Institute of Developmental Biology and Cancer Research, CNRS UMR 6543 Centre A, Lacassagne, 06189 Nice, France
| | - Maureen A. McGargill
- From the From the Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Douglas R. Green
- From the From the Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Thirumala-Devi Kanneganti
- From the From the Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
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Host cell autophagy in immune response to zoonotic infections. Clin Dev Immunol 2011; 2012:910525. [PMID: 22110539 PMCID: PMC3205612 DOI: 10.1155/2012/910525] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2011] [Accepted: 09/26/2011] [Indexed: 12/15/2022]
Abstract
Autophagy is a fundamental homeostatic process in which cytoplasmic targets are sequestered within double-membraned autophagosomes and subsequently delivered to lysosomes for degradation. Accumulating evidence supports the pivotal role of autophagy in host defense against intracellular pathogens implicating both innate and adaptive immunity. Many of these pathogens cause common zoonotic infections worldwide. The induction of the autophagic machinery by innate immune receptors signaling, such as TLRs, NOD1/2, and p62/SQSTM1 in antigen-presenting cells results in inhibition of survival and elimination of invading pathogens. Furthermore, Th1 cytokines induce the autophagic process, whereas autophagy also contributes to antigen processing and MHC class II presentation, linking innate to adaptive immunity. However, several pathogens have developed strategies to avoid autophagy or exploit autophagic machinery to their advantage. This paper focuses on the role of host cell autophagy in the regulation of immune response against intracellular pathogens, emphasizing on selected bacterial and protozoan zoonoses.
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Human rhinovirus 2 induces the autophagic pathway and replicates more efficiently in autophagic cells. J Virol 2011; 85:9651-4. [PMID: 21752910 DOI: 10.1128/jvi.00316-11] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Picornaviruses rearrange cellular membranes to form cytosolic replication sites. In the case of poliovirus and several other picornaviruses, these membranes are derived from subversion of the cellular autophagy pathway. We also reported observation of autophagosome-like structures during infection by two human rhinoviruses (HRVs), HRV-2 and HRV-14 (W. T. Jackson et al., PLoS Biol. 3:e156, 2005). Another group reported that HRV-2 does not induce autophagosomes or respond to changes in cellular autophagy (M. Brabec-Zaruba, U. Berka, D. Blaas, and R. Fuchs, J. Virol. 81:10815-10817, 2007). In this study, we tested HRV-2-infected cells for activation of autophagic signaling and changes in virus growth in response to changes in autophagy levels. Our data indicate that HRV-2 induces and subverts the autophagic machinery to promote its own replication.
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Xu C, Liu J, Hsu LC, Luo Y, Xiang R, Chuang TH. Functional interaction of heat shock protein 90 and Beclin 1 modulates Toll-like receptor-mediated autophagy. FASEB J 2011; 25:2700-10. [PMID: 21543763 DOI: 10.1096/fj.10-167676] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Autophagy is one of the downstream effector mechanisms for elimination of intracellular microbes following activation of the Toll-like receptors (TLRs). Although the detailed molecular mechanism for this cellular process is still unclear, Beclin 1, a key molecule for autophagy, has been suggested to play a role. Heat shock protein 90 (Hsp90) is a molecular chaperone that regulates the stability of signaling proteins. Herein, we show that Hsp90 forms a complex with Beclin 1 through an evolutionarily conserved domain to maintain the stability of Beclin 1. In monocytic cells, geldanamycin (GA), an Hsp90 inhibitor, effectively promoted proteasomal degradation of Beclin 1 in a concentration-dependent (EC(50) 100 nM) and time-dependent (t(50) 2 h) manner. In contrast, KNK437/Hsp inhibitor I had no effect. Hsp90 specifically interacted with Beclin 1 but not with other adapter proteins in the TLR signalsome. Treatment of cells with GA inhibited TLR3- and TLR4-mediated autophagy. In addition, S. typhimurium infection-induced autophagy was blocked by GA treatment. This further suggested a role of the Hsp90/Beclin 1 in controlling autophagy in response to microbial infections. Taken together, our data revealed that by maintaining the homeostasis of Beclin 1, Hsp90 plays a novel role in TLR-mediated autophagy.
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Affiliation(s)
- Congfeng Xu
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
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Kageyama S, Omori H, Saitoh T, Sone T, Guan JL, Akira S, Imamoto F, Noda T, Yoshimori T. The LC3 recruitment mechanism is separate from Atg9L1-dependent membrane formation in the autophagic response against Salmonella. Mol Biol Cell 2011; 22:2290-300. [PMID: 21525242 PMCID: PMC3128531 DOI: 10.1091/mbc.e10-11-0893] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
When Salmonella invade mammalian epithelial cells, some populations are surrounded by the autophagy protein LC3. We found that LC3 was recruited in proximity to Salmonella independently of both Atg9L1 and FIP200, which are required for formation of autophagosomes. The dynamics of the ULK1 complex and Atg9L1 were dependent on one another. Salmonella develops into resident bacteria in epithelial cells, and the autophagic machinery (Atg) is thought to play an important role in this process. In this paper, we show that an autophagosome-like double-membrane structure surrounds the Salmonella still residing within the Salmonella-containing vacuole (SCV). This double membrane is defective in Atg9L1- and FAK family-interacting protein of 200 kDa (FIP200)-deficient cells. Atg9L1 and FIP200 are important for autophagy-specific recruitment of the phosphatidylinositol 3-kinase (PI3K) complex. However, in the absence of Atg9L1, FIP200, and the PI3K complex, LC3 and its E3-like enzyme, the Atg16L complex, are still recruited to Salmonella. We propose that the LC3 system is recruited through a mechanism that is independent of isolation membrane generation.
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Affiliation(s)
- Shun Kageyama
- Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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Hubber A, Roy CR. Modulation of host cell function by Legionella pneumophila type IV effectors. Annu Rev Cell Dev Biol 2010; 26:261-83. [PMID: 20929312 DOI: 10.1146/annurev-cellbio-100109-104034] [Citation(s) in RCA: 359] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Macrophages and protozoa ingest bacteria by phagocytosis and destroy these microbes using a conserved pathway that mediates fusion of the phagosome with lysosomes. To survive within phagocytic host cells, bacterial pathogens have evolved a variety of strategies to avoid fusion with lysosomes. A virulence strategy used by the intracellular pathogen Legionella pneumophila is to manipulate host cellular processes using bacterial proteins that are delivered into the cytosolic compartment of the host cell by a specialized secretion system called Dot/Icm. The proteins delivered by the Dot/Icm system target host factors that play evolutionarily conserved roles in controlling membrane transport in eukaryotic cells, which enables L. pneumophila to create an endoplasmic reticulum-like vacuole that supports intracellular replication in both protozoan and mammalian host cells. This review focuses on intracellular trafficking of L. pneumophila and describes how bacterial proteins contribute to modulation of host processes required for survival within host cells.
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Affiliation(s)
- Andree Hubber
- Section of Microbial Pathogenesis, School of Medicine, Yale University, New Haven, Connecticut 06536, USA.
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