801
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Abstract
Autophagy has broad functions in immunity, ranging from cell-autonomous defence to coordination of complex multicellular immune responses. The successful resolution of infection and avoidance of autoimmunity necessitates efficient and timely communication between autophagy and pathways that sense the immune environment. The recent literature indicates that a variety of immune mediators induce or repress autophagy. It is also becoming increasingly clear that immune signalling cascades are subject to regulation by autophagy, and that a return to homeostasis following a robust immune response is critically dependent on this pathway. Importantly, examples of non-canonical forms of autophagy in mediating immunity are pervasive. In this article, the progress in elucidating mechanisms of crosstalk between autophagy and inflammatory signalling cascades is reviewed. Improved mechanistic understanding of the autophagy machinery offers hope for treating infectious and inflammatory diseases.
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Affiliation(s)
- Ken Cadwell
- grid.137628.90000 0004 1936 8753and the Department of Microbiology, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, 10016 New York USA
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802
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Bingol B, Sheng M. Mechanisms of mitophagy: PINK1, Parkin, USP30 and beyond. Free Radic Biol Med 2016; 100:210-222. [PMID: 27094585 DOI: 10.1016/j.freeradbiomed.2016.04.015] [Citation(s) in RCA: 209] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/15/2016] [Accepted: 04/15/2016] [Indexed: 12/16/2022]
Abstract
Mitochondrial quality control is central for maintaining a healthy population of mitochondria. Two Parkinson's disease genes, mitochondrial kinase PINK1 and ubiquitin ligase Parkin, degrade damaged mitochondria though mitophagy. In this pathway, PINK1 senses mitochondrial damage and activates Parkin by phosphorylating Parkin and ubiquitin. Activated Parkin then builds ubiquitin chains on damaged mitochondria to tag them for degradation in lysosomes. USP30 deubiquitinase acts as a brake on mitophagy by opposing Parkin-mediated ubiquitination. Human genetic data point to a role for mitophagy defects in neurodegenerative diseases. This review highlights the molecular mechanisms of the mitophagy pathway and the recent advances in the understanding of mitophagy in vivo.
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Affiliation(s)
- Baris Bingol
- Department of Neuroscience, Genentech Inc, South San Francisco, CA 94080, USA.
| | - Morgan Sheng
- Department of Neuroscience, Genentech Inc, South San Francisco, CA 94080, USA
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803
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Mitochondria as Molecular Platforms Integrating Multiple Innate Immune Signalings. J Mol Biol 2016; 429:1-13. [PMID: 27923767 DOI: 10.1016/j.jmb.2016.10.028] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 10/20/2016] [Accepted: 10/23/2016] [Indexed: 12/14/2022]
Abstract
The immune system of vertebrates confers protective mechanisms to the host through the sensing of stress-induced agents expressed during infection or cell stress. Among them, the first line of host defense composed of the innate immune sensing of these agents by pattern recognition receptors enables downstream adaptive immunity to be primed, mediating the body's appropriate response to clear infection and tissue damage. Mitochondria are «bacteria within» that allowed the emergence of functional eukaryotic cells by positioning themselves as the cell powerhouse and an initiator of cell death programs. It is striking to consider that such ancestral bacteria, which had to evade host defense at some point to develop evolutionary endosymbiosis, have become instrumental for the modern eukaryotic cell in alerting the immune system against various insults including infection by other pathogens. Mitochondria have indeed become critical regulators of innate immune responses to both pathogens and cell stress. They host numerous modulators, which play a direct role into the assembly of innate sensing machineries that trigger host immune response in both sterile and non-sterile conditions. Several lines of evidence indicate the existence of a complex molecular interplay between mechanisms involved in inflammation and metabolism. Mitochondrial function seems to participate in innate immunity at various stages as diverse as the transcriptional regulation of inflammatory cytokines and chemokines and their maturation by inflammasomes. Here, we review the mechanisms by which mitochondria orchestrate innate immune responses at different levels by promoting a cellular metabolic reprogramming and the cytosolic immune signaling cascades.
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804
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Sandhir R, Halder A, Sunkaria A. Mitochondria as a centrally positioned hub in the innate immune response. Biochim Biophys Acta Mol Basis Dis 2016; 1863:1090-1097. [PMID: 27794419 DOI: 10.1016/j.bbadis.2016.10.020] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 10/21/2016] [Accepted: 10/22/2016] [Indexed: 12/28/2022]
Abstract
Mitochondria are vital organelles involved in numerous cellular functions ranging from energy metabolism to cell survival. Emerging evidence suggests that mitochondria provide a platform for signaling pathways involved in innate immune response. Mitochondrial ROS (mtROS) production, mitochondrial DNA (mtDNA) release, mitochondrial antiviral signaling protein (MAVS) are key triggers in the activation of innate immune response following variety of stress signals that include infection, tissue damage and metabolic dysregulation. The process is mediated through pattern recognition receptors (PRRs) that consist of retinoic acid inducible gene like receptors (RLRs), c-type lectin receptors (CLRs), toll type receptors (TLRs) and nuclear oligomerization-domain like receptors (NLRs). These signals converge to form a multiprotein complex called inflammasome that leads to caspase-1 activation to promote processing of precursor cytokines (pro-IL1β and pro-IL-18) to active cytokines (IL-1β and IL-18). It appears that mitochondria induced inflammasome activation contributes to inflammatory process in many diverse disorders. Therefore, strategies aimed at modulating mitochondria mediated inflammasome activation might be beneficial in many pathophysiological conditions. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.
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Affiliation(s)
- Rajat Sandhir
- Department of Biochemistry, Panjab University, Chandigarh, India.
| | - Avishek Halder
- Department of Biochemistry, Panjab University, Chandigarh, India
| | - Aditya Sunkaria
- Department of Biochemistry, Panjab University, Chandigarh, India
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805
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Moretti J, Blander JM. Cell-autonomous stress responses in innate immunity. J Leukoc Biol 2016; 101:77-86. [PMID: 27733577 DOI: 10.1189/jlb.2mr0416-201r] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 08/10/2016] [Accepted: 08/24/2016] [Indexed: 12/12/2022] Open
Abstract
The innate immune response of phagocytes to microbes has long been known to depend on the core signaling cascades downstream of pattern recognition receptors (PRRs), which lead to expression and production of inflammatory cytokines that counteract infection and induce adaptive immunity. Cell-autonomous responses have recently emerged as important mechanisms of innate immunity. Either IFN-inducible or constitutive, these processes aim to guarantee cell homeostasis but have also been shown to modulate innate immune response to microbes and production of inflammatory cytokines. Among these constitutive cell-autonomous responses, autophagy is prominent and its role in innate immunity has been well characterized. Other stress responses, such as metabolic stress, the ER stress/unfolded protein response, mitochondrial stress, or the DNA damage response, seem to also be involved in innate immunity, although the precise mechanisms by which they regulate the innate immune response are not yet defined. Of importance, these distinct constitutive cell-autonomous responses appear to be interconnected and can also be modulated by microbes and PRRs, which add further complexity to the interplay between innate immune signaling and cell-autonomous responses in the mediation of an efficient innate immune response.
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Affiliation(s)
- Julien Moretti
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - J Magarian Blander
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA; .,Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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806
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Sallmyr A, Matsumoto Y, Roginskaya V, Van Houten B, Tomkinson AE. Inhibiting Mitochondrial DNA Ligase IIIα Activates Caspase 1-Dependent Apoptosis in Cancer Cells. Cancer Res 2016; 76:5431-41. [PMID: 27503931 PMCID: PMC5036517 DOI: 10.1158/0008-5472.can-15-3243] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 06/30/2016] [Indexed: 01/09/2023]
Abstract
Elevated levels of DNA ligase IIIα (LigIIIα) have been identified as a biomarker of an alteration in DNA repair in cancer cells that confers hypersensitivity to a LigIIIα inhibitor, L67, in combination with a poly (ADP-ribose) polymerase inhibitor. Because LigIIIα functions in the nucleus and mitochondria, we examined the effect of L67 on these organelles. Here, we show that, although the DNA ligase inhibitor selectively targets mitochondria, cancer and nonmalignant cells respond differently to disruption of mitochondrial DNA metabolism. Inhibition of mitochondrial LigIIIα in cancer cells resulted in abnormal mitochondrial morphology, reduced levels of mitochondrial DNA, and increased levels of mitochondrially generated reactive oxygen species that caused nuclear DNA damage. In contrast, these effects did not occur in nonmalignant cells. Furthermore, inhibition of mitochondrial LigIIIα activated a caspase 1-dependent apoptotic pathway, which is known to be part of inflammatory responses induced by pathogenic microorganisms in cancer, but not nonmalignant cells. These results demonstrate that the disruption of mitochondrial DNA metabolism elicits different responses in nonmalignant and cancer cells and suggests that the abnormal response in cancer cells may be exploited in the development of novel therapeutic strategies that selectively target cancer cells. Cancer Res; 76(18); 5431-41. ©2016 AACR.
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Affiliation(s)
- Annahita Sallmyr
- Departments of Internal Medicine and Molecular Genetics and Microbiology, and University of New Mexico Cancer Center, University of New Mexico, Albuquerque, New Mexico
| | - Yoshihiro Matsumoto
- Departments of Internal Medicine and Molecular Genetics and Microbiology, and University of New Mexico Cancer Center, University of New Mexico, Albuquerque, New Mexico
| | - Vera Roginskaya
- Department of Pharmacology and Cell Biology, University of Pittsburgh School of Medicine and The University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, Pennsylvania
| | - Bennett Van Houten
- Department of Pharmacology and Cell Biology, University of Pittsburgh School of Medicine and The University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, Pennsylvania
| | - Alan E Tomkinson
- Departments of Internal Medicine and Molecular Genetics and Microbiology, and University of New Mexico Cancer Center, University of New Mexico, Albuquerque, New Mexico.
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807
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Yu JW, Lee MS. Mitochondria and the NLRP3 inflammasome: physiological and pathological relevance. Arch Pharm Res 2016; 39:1503-1518. [PMID: 27600432 DOI: 10.1007/s12272-016-0827-4] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 08/29/2016] [Indexed: 01/12/2023]
Abstract
The NLRP3 inflammasome is assembled and activated in certain types of myeloid cells upon sensing microbe-derived toxins or host-derived danger signals. Activation of the NLRP3 inflammasome by endogenous ligands has been discovered in various disorders, including metabolic syndrome, type 2 diabetes, atherosclerosis, gout, reperfusion injury of the heart, neurodegeneration, such as Alzheimer's disease, chronic kidney diseases, and macular degeneration of the eyes. Despite the potential significance of the NLRP3 inflammasome in the pathogenesis of several diseases, details on the activation mechanism of the NLRP3 inflammasome by a variety of stimulators have yet to be reported. Emerging evidence suggests that mitochondrial events are associated with NLRP3 activation in disease conditions. Mitochondrial dysfunction acts upstream of NLRP3 activation by providing reactive oxygen species (ROS) to trigger NLRP3 oligomerization or by inducing α-tubulin acetylation to relocate mitochondria to the proximity of NLRP3. In addition, mitochondria work as a platform for inflammasome assembly. Mitochondrial events may also lie downstream of NLRP3 activation. While the molecular mechanisms of mitochondrial dysfunction associated with NLRP3 activation are still unclear, they may involve the perturbation of mitochondria by K+ efflux and subsequent intracellular disequilibrium. Thus, mitochondria and NLRP3 machinery appear to be closely interwoven at multiple levels.
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Affiliation(s)
- Je-Wook Yu
- Department of Microbiology and Immunology, BK 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Myung-Shik Lee
- Severance Biomedical Science Institute and Department of Internal Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea.
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808
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Abstract
Mitochondria play a key role in various cell processes including ATP production, Ca2+ homeostasis, reactive oxygen species (ROS) generation, and apoptosis. The selective removal of impaired mitochondria by autophagosome is known as mitophagy. Cerebral ischemia is a common form of stroke caused by insufficient blood supply to the brain. Emerging evidence suggests that mitophagy plays important roles in the pathophysiological process of cerebral ischemia. This review focuses on the relationship between ischemic brain injury and mitophagy. Based on the latest research, it describes how the signaling pathways of mitophagy appear to be involved in cerebral ischemia.
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809
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Taniguchi K, Yamachika S, He F, Karin M. p62/SQSTM1-Dr. Jekyll and Mr. Hyde that prevents oxidative stress but promotes liver cancer. FEBS Lett 2016; 590:2375-97. [PMID: 27404485 DOI: 10.1002/1873-3468.12301] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 07/08/2016] [Accepted: 07/09/2016] [Indexed: 12/17/2022]
Abstract
p62/SQSTM1 is a multifunctional signaling hub and autophagy adaptor with many binding partners, which allow it to activate mTORC1-dependent nutrient sensing, NF-κB-mediated inflammatory responses, and the NRF2-activated antioxidant defense. p62 recognizes polyubiquitin chains via its C-terminal domain and binds to LC3 via its LIR motif, thereby promoting the autophagic degradation of ubiquitinated cargos. p62 accumulates in many human liver diseases, including nonalcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC), where it is a component of Mallory-Denk bodies and intracellular hyaline bodies. Chronic p62 elevation contributes to HCC development by preventing oncogene-induced senescence and death of cancer-initiating cells and enhancing their proliferation. In this review, we discuss p62-mediated signaling pathways and their roles in liver pathophysiology, especially NASH and HCC.
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Affiliation(s)
- Koji Taniguchi
- Laboratory of Gene Regulation and Signal Transduction, Departments of Pharmacology and Pathology, University of California San Diego, La Jolla, CA, USA.,Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.,Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo, Japan
| | - Shinichiro Yamachika
- Laboratory of Gene Regulation and Signal Transduction, Departments of Pharmacology and Pathology, University of California San Diego, La Jolla, CA, USA
| | - Feng He
- Laboratory of Gene Regulation and Signal Transduction, Departments of Pharmacology and Pathology, University of California San Diego, La Jolla, CA, USA
| | - Michael Karin
- Laboratory of Gene Regulation and Signal Transduction, Departments of Pharmacology and Pathology, University of California San Diego, La Jolla, CA, USA
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810
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Wolf AJ, Reyes CN, Liang W, Becker C, Shimada K, Wheeler ML, Cho HC, Popescu NI, Coggeshall KM, Arditi M, Underhill DM. Hexokinase Is an Innate Immune Receptor for the Detection of Bacterial Peptidoglycan. Cell 2016; 166:624-636. [PMID: 27374331 PMCID: PMC5534359 DOI: 10.1016/j.cell.2016.05.076] [Citation(s) in RCA: 390] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 03/11/2016] [Accepted: 05/25/2016] [Indexed: 12/31/2022]
Abstract
Degradation of Gram-positive bacterial cell wall peptidoglycan in macrophage and dendritic cell phagosomes leads to activation of the NLRP3 inflammasome, a cytosolic complex that regulates processing and secretion of interleukin (IL)-1β and IL-18. While many inflammatory responses to peptidoglycan are mediated by detection of its muramyl dipeptide component in the cytosol by NOD2, we report here that NLRP3 inflammasome activation is caused by release of N-acetylglucosamine that is detected in the cytosol by the glycolytic enzyme hexokinase. Inhibition of hexokinase by N-acetylglucosamine causes its dissociation from mitochondria outer membranes, and we found that this is sufficient to activate the NLRP3 inflammasome. In addition, we observed that glycolytic inhibitors and metabolic conditions affecting hexokinase function and localization induce inflammasome activation. While previous studies have demonstrated that signaling by pattern recognition receptors can regulate metabolic processes, this study shows that a metabolic enzyme can act as a pattern recognition receptor. PAPERCLIP.
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Affiliation(s)
- Andrea J Wolf
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Christopher N Reyes
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Wenbin Liang
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Courtney Becker
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Kenichi Shimada
- Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Division of Pediatric Infectious Diseases, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Matthew L Wheeler
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Hee Cheol Cho
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Narcis I Popescu
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - K Mark Coggeshall
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Moshe Arditi
- Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Division of Pediatric Infectious Diseases, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - David M Underhill
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
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811
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Abstract
NLRP3 inflammasome activation is accompanied by induction of mitochondrial damage. In the current issue of Cell, Zhong et al. describe an intracellular mechanism orchestrated by NF-κB to remove inflammasome-activating damaged mitochondria and prevent pathologic inflammation.
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Affiliation(s)
- Alice Lepelley
- Department of Microbiology & Immunology, Columbia University, College of Physicians & Surgeons, New York, NY 10032, USA
| | - Sankar Ghosh
- Department of Microbiology & Immunology, Columbia University, College of Physicians & Surgeons, New York, NY 10032, USA.
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812
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Lerner CA, Sundar IK, Rahman I. Mitochondrial redox system, dynamics, and dysfunction in lung inflammaging and COPD. Int J Biochem Cell Biol 2016; 81:294-306. [PMID: 27474491 DOI: 10.1016/j.biocel.2016.07.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 07/21/2016] [Accepted: 07/23/2016] [Indexed: 01/01/2023]
Abstract
Myriad forms of endogenous and environmental stress disrupt mitochondrial function by impacting critical processes in mitochondrial homeostasis, such as mitochondrial redox system, oxidative phosphorylation, biogenesis, and mitophagy. External stressors that interfere with the steady state activity of mitochondrial functions are generally associated with an increase in reactive oxygen species, inflammatory response, and induction of cellular senescence (inflammaging) potentially via mitochondrial damage associated molecular patterns (DAMPS). Many of these are the key events in the pathogenesis of chronic obstructive pulmonary disease (COPD) and its exacerbations. In this review, we highlight the primary mitochondrial quality control mechanisms that are influenced by oxidative stress/redox system, including role of mitochondria during inflammation and cellular senescence, and how mitochondrial dysfunction contributes to the pathogenesis of COPD and its exacerbations via pathogenic stimuli.
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Affiliation(s)
- Chad A Lerner
- Department of Environmental Medicine, Lung Biology and Disease Program, University of Rochester Medical Center, Rochester, NY, USA
| | - Isaac K Sundar
- Department of Environmental Medicine, Lung Biology and Disease Program, University of Rochester Medical Center, Rochester, NY, USA
| | - Irfan Rahman
- Department of Environmental Medicine, Lung Biology and Disease Program, University of Rochester Medical Center, Rochester, NY, USA.
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813
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Zhong Z, Sanchez-Lopez E, Karin M. Autophagy, Inflammation, and Immunity: A Troika Governing Cancer and Its Treatment. Cell 2016; 166:288-298. [PMID: 27419869 PMCID: PMC4947210 DOI: 10.1016/j.cell.2016.05.051] [Citation(s) in RCA: 466] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/05/2016] [Accepted: 05/16/2016] [Indexed: 12/27/2022]
Abstract
Autophagy, a cellular waste disposal process, has well-established tumor-suppressive properties. New studies indicate that, in addition to its cell-autonomous anti-tumorigenic functions, autophagy inhibits cancer development by orchestrating inflammation and immunity. While attenuating tumor-promoting inflammation, autophagy enhances the processing and presentation of tumor antigens and thereby stimulates anti-tumor immunity. Although cancer cells can escape immunosurveillance by tuning down autophagy, certain chemotherapeutic agents with immunogenic properties may enhance anti-tumor immunity by inducing autophagic cell death. Understanding the intricate and complex relationships within this troika and how they are affected by autophagy enhancing drugs should improve the efficacy of cancer immunotherapy.
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Affiliation(s)
- Zhenyu Zhong
- Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Pathology, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Elsa Sanchez-Lopez
- Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Pathology, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Michael Karin
- Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Pathology, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
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814
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Yang J, Liu Z, Xiao TS. Post-translational regulation of inflammasomes. Cell Mol Immunol 2016; 14:65-79. [PMID: 27345727 PMCID: PMC5214939 DOI: 10.1038/cmi.2016.29] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 05/05/2016] [Accepted: 05/05/2016] [Indexed: 12/16/2022] Open
Abstract
Inflammasomes play essential roles in immune protection against microbial infections. However, excessive inflammation is implicated in various human diseases, including autoinflammatory syndromes, diabetes, multiple sclerosis, cardiovascular disorders and neurodegenerative diseases. Therefore, precise regulation of inflammasome activities is critical for adequate immune protection while limiting collateral tissue damage. In this review, we focus on the emerging roles of post-translational modifications (PTMs) that regulate activation of the NLRP3, NLRP1, NLRC4, AIM2 and IFI16 inflammasomes. We anticipate that these types of PTMs will be identified in other types of and less well-characterized inflammasomes. Because these highly diverse and versatile PTMs shape distinct inflammatory responses in response to infections and tissue damage, targeting the enzymes involved in these PTMs will undoubtedly offer opportunities for precise modulation of inflammasome activities under various pathophysiological conditions.
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Affiliation(s)
- Jie Yang
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106-7288, USA.,Graduate Program in Physiology and Biophysics, Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106-7288, USA
| | - Zhonghua Liu
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106-7288, USA
| | - Tsan Sam Xiao
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106-7288, USA
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815
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Kabat AM, Pott J, Maloy KJ. The Mucosal Immune System and Its Regulation by Autophagy. Front Immunol 2016; 7:240. [PMID: 27446072 PMCID: PMC4916208 DOI: 10.3389/fimmu.2016.00240] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 06/07/2016] [Indexed: 12/20/2022] Open
Abstract
The gastrointestinal tract presents a unique challenge to the mucosal immune system, which has to constantly monitor the vast surface for the presence of pathogens, while at the same time maintaining tolerance to beneficial or innocuous antigens. In the intestinal mucosa, specialized innate and adaptive immune components participate in directing appropriate immune responses toward these diverse challenges. Recent studies provide compelling evidence that the process of autophagy influences several aspects of mucosal immune responses. Initially described as a “self-eating” survival pathway that enables nutrient recycling during starvation, autophagy has now been connected to multiple cellular responses, including several aspects of immunity. Initial links between autophagy and host immunity came from the observations that autophagy can target intracellular bacteria for degradation. However, subsequent studies indicated that autophagy plays a much broader role in immune responses, as it can impact antigen processing, thymic selection, lymphocyte homeostasis, and the regulation of immunoglobulin and cytokine secretion. In this review, we provide a comprehensive overview of mucosal immune cells and discuss how autophagy influences many aspects of their physiology and function. We focus on cell type-specific roles of autophagy in the gut, with a particular emphasis on the effects of autophagy on the intestinal T cell compartment. We also provide a perspective on how manipulation of autophagy may potentially be used to treat mucosal inflammatory disorders.
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Affiliation(s)
- Agnieszka M Kabat
- Sir William Dunn School of Pathology, University of Oxford , Oxford , UK
| | - Johanna Pott
- Sir William Dunn School of Pathology, University of Oxford , Oxford , UK
| | - Kevin J Maloy
- Sir William Dunn School of Pathology, University of Oxford , Oxford , UK
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816
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Próchnicki T, Mangan MS, Latz E. Recent insights into the molecular mechanisms of the NLRP3 inflammasome activation. F1000Res 2016; 5. [PMID: 27508077 PMCID: PMC4963208 DOI: 10.12688/f1000research.8614.1] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/17/2016] [Indexed: 12/26/2022] Open
Abstract
Inflammasomes are high-molecular-weight protein complexes that are formed in the cytosolic compartment in response to danger- or pathogen-associated molecular patterns. These complexes enable activation of an inflammatory protease caspase-1, leading to a cell death process called pyroptosis and to proteolytic cleavage and release of pro-inflammatory cytokines interleukin (IL)-1β and IL-18. Along with caspase-1, inflammasome components include an adaptor protein, ASC, and a sensor protein, which triggers the inflammasome assembly in response to a danger signal. The inflammasome sensor proteins are pattern recognition receptors belonging either to the NOD-like receptor (NLR) or to the AIM2-like receptor family. While the molecular agonists that induce inflammasome formation by AIM2 and by several other NLRs have been identified, it is not well understood how the NLR family member NLRP3 is activated. Given that NLRP3 activation is relevant to a range of human pathological conditions, significant attempts are being made to elucidate the molecular mechanism of this process. In this review, we summarize the current knowledge on the molecular events that lead to activation of the NLRP3 inflammasome in response to a range of K (+) efflux-inducing danger signals. We also comment on the reported involvement of cytosolic Ca (2+) fluxes on NLRP3 activation. We outline the recent advances in research on the physiological and pharmacological mechanisms of regulation of NLRP3 responses, and we point to several open questions regarding the current model of NLRP3 activation.
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Affiliation(s)
- Tomasz Próchnicki
- Institute of Innate Immunity, University Hospital, University of Bonn, Bonn, Germany
| | - Matthew S Mangan
- Institute of Innate Immunity, University Hospital, University of Bonn, Bonn, Germany; German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Eicke Latz
- Institute of Innate Immunity, University Hospital, University of Bonn, Bonn, Germany; Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, USA; German Center for Neurodegenerative Diseases, Bonn, Germany; Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway
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817
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Saitoh T, Akira S. Regulation of inflammasomes by autophagy. J Allergy Clin Immunol 2016; 138:28-36. [PMID: 27373323 DOI: 10.1016/j.jaci.2016.05.009] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 05/17/2016] [Accepted: 05/18/2016] [Indexed: 12/15/2022]
Abstract
Inflammasomes detect pathogen-associated molecular patterns to induce inflammatory innate immune responses and play a key role in host defense against infectious agents. However, inflammasomes are often wrongly activated by metabolites, amyloids, and environmental irritants. This induces massive inflammation, causing severe tissue damage, and results in the development of inflammatory diseases. Hence cellular machineries regulating both "activation" and "inactivation" of inflammasomes are definitely important. Recent studies have shown that autophagy, an intracellular degradation system associated with maintenance of cellular homeostasis, plays a key role in inflammasome inactivation. Notably, autophagy deficiency caused by gene mutation disrupts organelle elimination and thus induces aberrant activation of inflammasomes, leading to severe tissue damage. Here we review recent findings regarding the involvement of autophagy in the regulation of inflammasome activation and development of inflammatory disorders.
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Affiliation(s)
- Tatsuya Saitoh
- Department of Inflammation Biology, Institute for Enzyme Research, Tokushima University, Tokushima, Japan.
| | - Shizuo Akira
- Laboratory of Host Defense, World Premier International Research Center Immunology Frontier Research Center, Osaka, Japan; Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
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818
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Sugimoto MA, Sousa LP, Pinho V, Perretti M, Teixeira MM. Resolution of Inflammation: What Controls Its Onset? Front Immunol 2016. [PMID: 27199985 DOI: 10.3389/fimmu.2016.00.00160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
An effective resolution program may be able to prevent the progression from non-resolving acute inflammation to persistent chronic inflammation. It has now become evident that coordinated resolution programs initiate shortly after inflammatory responses begin. In this context, several mechanisms provide the fine-tuning of inflammation and create a favorable environment for the resolution phase to take place and for homeostasis to return. In this review, we focus on the events required for an effective transition from the proinflammatory phase to the onset and establishment of resolution. We suggest that several mediators that promote the inflammatory phase of inflammation can simultaneously initiate a program for active resolution. Indeed, several events enact a decrease in the local chemokine concentration, a reduction which is essential to inhibit further infiltration of neutrophils into the tissue. Interestingly, although neutrophils are cells that characteristically participate in the active phase of inflammation, they also contribute to the onset of resolution. Further understanding of the molecular mechanisms that initiate resolution may be instrumental to develop pro-resolution strategies to treat complex chronic inflammatory diseases, in humans. The efforts to develop strategies based on resolution of inflammation have shaped a new area of pharmacology referred to as "resolution pharmacology."
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Affiliation(s)
- Michelle A Sugimoto
- Laboratório de Sinalização Inflamação, Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Lirlândia P Sousa
- Laboratório de Sinalização Inflamação, Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Vanessa Pinho
- Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Laboratório de Resolução da Resposta Inflamatória, Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Mauro Perretti
- William Harvey Research Institute, Barts and The London School of Medicine, Queen Mary University of London , London , UK
| | - Mauro M Teixeira
- Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais , Belo Horizonte , Brazil
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819
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David CA, Owen A, Liptrott NJ. Determining the relationship between nanoparticle characteristics and immunotoxicity: key challenges and approaches. Nanomedicine (Lond) 2016; 11:1447-64. [PMID: 27171671 DOI: 10.2217/nnm-2016-0017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The growing wealth of information regarding the influence that physicochemical characteristics play on nanoparticle biocompatibility and safety is allowing improved design and rationale for their development and preclinical assessment. Accurate and appropriate measurement of these characteristics accompanied by informed toxicological assessment is a necessity for the development of safe and effective nanomedicines. While particle type, formulation and mode of administration dictate the individual causes for concern through development, the benefits of nanoformulation for treatment of the diseased state are great. Here we have proposed certain considerations and suggestions, which could lead to better-informed preclinical assessment of nanomaterials for nanomedicine, as well as how this information can and should be extrapolated to the physiological state of the end user.
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Affiliation(s)
- Christopher Aw David
- European Nanotechnology Characterization Lab, University of Liverpool, Molecular & Clinical Pharmacology, 70 Pembroke Place, Liverpool, L69 3GF, UK
| | - Andrew Owen
- European Nanotechnology Characterization Lab, University of Liverpool, Molecular & Clinical Pharmacology, 70 Pembroke Place, Liverpool, L69 3GF, UK
| | - Neill J Liptrott
- European Nanotechnology Characterization Lab, University of Liverpool, Molecular & Clinical Pharmacology, 70 Pembroke Place, Liverpool, L69 3GF, UK
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820
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Karin M, Dhar D. Liver carcinogenesis: from naughty chemicals to soothing fat and the surprising role of NRF2. Carcinogenesis 2016; 37:541-6. [PMID: 27207669 DOI: 10.1093/carcin/bgw060] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 04/29/2016] [Indexed: 02/07/2023] Open
Abstract
The liver is a key metabolic organ that is essential for production of blood proteins, lipid and sugar metabolism and detoxification of naturally occurring and foreign harmful chemicals. To maintain its mass and many essential functions, the liver possesses remarkable regenerative capacity, but the latter also renders it highly susceptible to carcinogenesis. In fact, liver cancer often develops in the context of chronic liver injury. Currently, primary liver cancer is the second leading cause of cancer-related deaths, and as the rates of other cancers have been declining, the incidence of liver cancer continues to rise with an alarming rate. Although much remains to be accomplished in regards to liver cancer therapy, we have learned a great deal about the molecular etiology of the most common form of primary liver cancer, hepatocellular carcinoma (HCC). Much of this knowledge has been obtained from studies of mouse models, using either toxic chemicals, a combination of fatty foods and endoplasmic reticulum stress or chronic activation of specific metabolic pathways. Surprisingly, NRF2, a transcription factor that was initially thought to protect the liver from oxidative stress, was found to play a key role in promoting HCC pathogenesis.
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Affiliation(s)
- Michael Karin
- Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology, Department of Pathology and Moores Cancer Center, UCSD School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Debanjan Dhar
- Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology
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821
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Sugimoto MA, Sousa LP, Pinho V, Perretti M, Teixeira MM. Resolution of Inflammation: What Controls Its Onset? Front Immunol 2016; 7:160. [PMID: 27199985 PMCID: PMC4845539 DOI: 10.3389/fimmu.2016.00160] [Citation(s) in RCA: 395] [Impact Index Per Article: 49.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 04/12/2016] [Indexed: 12/12/2022] Open
Abstract
An effective resolution program may be able to prevent the progression from non-resolving acute inflammation to persistent chronic inflammation. It has now become evident that coordinated resolution programs initiate shortly after inflammatory responses begin. In this context, several mechanisms provide the fine-tuning of inflammation and create a favorable environment for the resolution phase to take place and for homeostasis to return. In this review, we focus on the events required for an effective transition from the proinflammatory phase to the onset and establishment of resolution. We suggest that several mediators that promote the inflammatory phase of inflammation can simultaneously initiate a program for active resolution. Indeed, several events enact a decrease in the local chemokine concentration, a reduction which is essential to inhibit further infiltration of neutrophils into the tissue. Interestingly, although neutrophils are cells that characteristically participate in the active phase of inflammation, they also contribute to the onset of resolution. Further understanding of the molecular mechanisms that initiate resolution may be instrumental to develop pro-resolution strategies to treat complex chronic inflammatory diseases, in humans. The efforts to develop strategies based on resolution of inflammation have shaped a new area of pharmacology referred to as “resolution pharmacology.”
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Affiliation(s)
- Michelle A Sugimoto
- Laboratório de Sinalização Inflamação, Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Lirlândia P Sousa
- Laboratório de Sinalização Inflamação, Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Vanessa Pinho
- Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Laboratório de Resolução da Resposta Inflamatória, Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Mauro Perretti
- William Harvey Research Institute, Barts and The London School of Medicine, Queen Mary University of London , London , UK
| | - Mauro M Teixeira
- Laboratório de Imunofarmacologia, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais , Belo Horizonte , Brazil
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822
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Man SM, Karki R, Kanneganti TD. DNA-sensing inflammasomes: regulation of bacterial host defense and the gut microbiota. Pathog Dis 2016; 74:ftw028. [PMID: 27056948 DOI: 10.1093/femspd/ftw028] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2016] [Indexed: 02/07/2023] Open
Abstract
DNA sensors are formidable immune guardians of the host. At least 14 cytoplasmic DNA sensors have been identified in recent years, each with specialized roles in driving inflammation and/or cell death. Of these, AIM2 is a sensor of dsDNA, and forms an inflammasome complex to activate the cysteine protease caspase-1, mediates the release of the proinflammatory cytokines IL-1β and IL-18, and induces pyroptosis. The inflammasome sensor NLRP3 can also respond to DNA in the forms of oxidized mitochondrial DNA and the DNA derivative RNA:DNA hybrids produced by bacteria, whereas the putative inflammasome sensor IFI16 responds to viral DNA in the nucleus. Although inflammasomes provoke inflammation for anti-microbial host defense, they must also maintain homeostasis with commensal microbiota. Here, we outline recent advances highlighting the complex relationship between DNA-sensing inflammasomes, bacterial host defense and the gut microbiota.
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Affiliation(s)
- Si Ming Man
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA
| | - Rajendra Karki
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA
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823
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Abstract
Protein ubiquitination is a dynamic multifaceted post-translational modification involved in nearly all aspects of eukaryotic biology. Once attached to a substrate, the 76-amino acid protein ubiquitin is subjected to further modifications, creating a multitude of distinct signals with distinct cellular outcomes, referred to as the 'ubiquitin code'. Ubiquitin can be ubiquitinated on seven lysine (Lys) residues or on the N-terminus, leading to polyubiquitin chains that can encompass complex topologies. Alternatively or in addition, ubiquitin Lys residues can be modified by ubiquitin-like molecules (such as SUMO or NEDD8). Finally, ubiquitin can also be acetylated on Lys, or phosphorylated on Ser, Thr or Tyr residues, and each modification has the potential to dramatically alter the signaling outcome. While the number of distinctly modified ubiquitin species in cells is mind-boggling, much progress has been made to characterize the roles of distinct ubiquitin modifications, and many enzymes and receptors have been identified that create, recognize or remove these ubiquitin modifications. We here provide an overview of the various ubiquitin modifications present in cells, and highlight recent progress on ubiquitin chain biology. We then discuss the recent findings in the field of ubiquitin acetylation and phosphorylation, with a focus on Ser65-phosphorylation and its role in mitophagy and Parkin activation.
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Affiliation(s)
- Kirby N Swatek
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - David Komander
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
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824
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