201
|
Bierschenk D, Boucher D, Schroder K. Salmonella- induced inflammasome activation in humans. Mol Immunol 2017; 86:38-43. [DOI: 10.1016/j.molimm.2016.11.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 11/01/2016] [Accepted: 11/17/2016] [Indexed: 12/21/2022]
|
202
|
Sharma D, Kanneganti TD. The cell biology of inflammasomes: Mechanisms of inflammasome activation and regulation. J Cell Biol 2017; 213:617-29. [PMID: 27325789 PMCID: PMC4915194 DOI: 10.1083/jcb.201602089] [Citation(s) in RCA: 500] [Impact Index Per Article: 71.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 05/27/2016] [Indexed: 02/08/2023] Open
Abstract
Over the past decade, numerous advances have been made in the role and regulation of inflammasomes during pathogenic and sterile insults. An inflammasome complex comprises a sensor, an adaptor, and a zymogen procaspase-1. The functional output of inflammasome activation includes secretion of cytokines, IL-1β and IL-18, and induction of an inflammatory form of cell death called pyroptosis. Recent studies have highlighted the intersection of this inflammatory response with fundamental cellular processes. Novel modulators and functions of inflammasome activation conventionally associated with the maintenance of homeostatic biological functions have been uncovered. In this review, we discuss the biological processes involved in the activation and regulation of the inflammasome.
Collapse
Affiliation(s)
- Deepika Sharma
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | | |
Collapse
|
203
|
Pfalzgraff A, Heinbockel L, Su Q, Brandenburg K, Weindl G. Synthetic anti-endotoxin peptides inhibit cytoplasmic LPS-mediated responses. Biochem Pharmacol 2017; 140:64-72. [PMID: 28539262 DOI: 10.1016/j.bcp.2017.05.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 05/19/2017] [Indexed: 10/19/2022]
Abstract
Toll-like receptor (TLR) 4-independent recognition of lipopolysaccharide (LPS) in the cytosol by inflammatory caspases leads to non-canonical inflammasome activation and induction of IL-1 secretion and pyroptosis. The discovery of this novel mechanism has potential implications for the development of effective drugs to treat sepsis since LPS-mediated hyperactivation of caspases is critically involved in endotoxic shock. Previously, we demonstrated that Pep19-2.5, a synthetic anti-endotoxin peptide, efficiently neutralises pathogenicity factors of Gram-negative and Gram-positive bacteria and protects against sepsis in vivo. Here, we report that Pep19-2.5 inhibits the effects of cytoplasmic LPS in human myeloid cells and keratinocytes. In THP-1 monocytes and macrophages, the peptide strongly reduced secretion of IL-1β and LDH induced by intracellular LPS. In contrast, the TLR4 signaling inhibitor TAK-242 abrogates LPS-induced TNF and IL-1β secretion, but not pyroptotic cell death. Furthermore, Pep19-2.5 suppressed LPS-induced HMGB-1 production and caspase-1 activation in THP-1 monocytes. Consistent with this observation, we found impaired IL-1β and IL-1α release in LPS-stimulated primary monocytes in the presence of Pep19-2.5 and reduced LDH release and IL-1B and IL-1A expression in LPS-transfected HaCaT keratinocytes. Additionally, Pep19-2.5 completely abolished IL-1β release induced by LPS/ATP in macrophages via canonical inflammasome activation. In conclusion, we provide evidence that anti-endotoxin peptides inhibit the inflammasome/IL-1 axis induced by cytoplasmic LPS sensing in myeloid cells and keratinocytes and activation of the classical inflammasome by LPS/ATP which may contribute to the protection against bacterial sepsis and skin infections with intracellular Gram-negative bacteria.
Collapse
Affiliation(s)
- Anja Pfalzgraff
- Freie Universität Berlin, Institute of Pharmacy (Pharmacology and Toxicology), Berlin, Germany
| | - Lena Heinbockel
- Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Divisions of Biophysics, Borstel, Germany
| | - Qi Su
- Freie Universität Berlin, Institute of Pharmacy (Pharmacology and Toxicology), Berlin, Germany
| | - Klaus Brandenburg
- Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Divisions of Biophysics, Borstel, Germany
| | - Günther Weindl
- Freie Universität Berlin, Institute of Pharmacy (Pharmacology and Toxicology), Berlin, Germany.
| |
Collapse
|
204
|
Yuan J, Najafov A, Py BF. Roles of Caspases in Necrotic Cell Death. Cell 2017; 167:1693-1704. [PMID: 27984721 DOI: 10.1016/j.cell.2016.11.047] [Citation(s) in RCA: 206] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 11/13/2016] [Accepted: 11/23/2016] [Indexed: 12/15/2022]
Abstract
Caspases were originally identified as important mediators of inflammatory response and apoptosis. Recent discoveries, however, have unveiled their roles in mediating and suppressing two regulated forms of necrotic cell death, termed pyroptosis and necroptosis, respectively. These recent advances have significantly expanded our understanding of the roles of caspases in regulating development, adult homeostasis, and host defense response.
Collapse
Affiliation(s)
- Junying Yuan
- Department of Cell Biology, Harvard Medical School, 240 Longwood Ave., Boston, MA 02115, USA; Ludwig Cancer Center, Harvard Medical School, 240 Longwood Ave., Boston, MA 02115, USA.
| | - Ayaz Najafov
- Department of Cell Biology, Harvard Medical School, 240 Longwood Ave., Boston, MA 02115, USA; Ludwig Cancer Center, Harvard Medical School, 240 Longwood Ave., Boston, MA 02115, USA
| | - Bénédicte F Py
- CIRI, Inserm U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, École Normale Supérieure de Lyon, Université de Lyon, 69007 Lyon, France
| |
Collapse
|
205
|
John CM, Phillips NJ, Stein DC, Jarvis GA. Innate immune response to lipooligosaccharide: pivotal regulator of the pathobiology of invasive Neisseria meningitidis infections. Pathog Dis 2017; 75:3569603. [PMID: 28423169 DOI: 10.1093/femspd/ftx030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 03/11/2017] [Indexed: 01/05/2023] Open
Abstract
Infections due to Neisseria meningitidis afflict more than one million people worldwide annually and cause death or disability in many survivors. The clinical course of invasive infections has been well studied, but our understanding of the cause of differences in patient outcomes has been limited because these are dependent on multiple factors including the response of the host, characteristics of the bacteria and interactions between the host and the bacteria. The meningococcus is a highly inflammatory organism, and the lipooligosaccharide (LOS) on the outer membrane is the most potent inflammatory molecule it expresses due to the interactions of the lipid A moiety of LOS with receptors of the innate immune system. We previously reported that increased phosphorylation of hexaacylated neisserial lipid A is correlated with greater inflammatory potential. Here we postulate that variability in lipid A phosphorylation can tip the balance of innate immune responses towards homeostatic tolerance or proinflammatory signaling that affects adaptive immune responses, causing disease with meningitis only, or septicemia with or without meningitis, respectively. Furthermore, we propose that studies of the relationship between bacterial virulence and gene expression should consider whether genetic variation could affect properties of biosynthetic enzymes resulting in LOS structural differences that alter disease pathobiology.
Collapse
Affiliation(s)
- Constance M John
- Center for Immunochemistry, Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA.,Department of Laboratory Medicine, University of California, San Francisco, CA 94143, USA
| | - Nancy J Phillips
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143, USA
| | - Daniel C Stein
- University of Maryland, Department of Cell Biology and Molecular Genetics, College Park, MD 20742 USA
| | - Gary A Jarvis
- Center for Immunochemistry, Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA.,Department of Laboratory Medicine, University of California, San Francisco, CA 94143, USA
| |
Collapse
|
206
|
Man SM, Karki R, Kanneganti TD. Molecular mechanisms and functions of pyroptosis, inflammatory caspases and inflammasomes in infectious diseases. Immunol Rev 2017; 277:61-75. [PMID: 28462526 PMCID: PMC5416822 DOI: 10.1111/imr.12534] [Citation(s) in RCA: 1089] [Impact Index Per Article: 155.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell death is a fundamental biological phenomenon that is essential for the survival and development of an organism. Emerging evidence also indicates that cell death contributes to immune defense against infectious diseases. Pyroptosis is a form of inflammatory programmed cell death pathway activated by human and mouse caspase-1, human caspase-4 and caspase-5, or mouse caspase-11. These inflammatory caspases are used by the host to control bacterial, viral, fungal, or protozoan pathogens. Pyroptosis requires cleavage and activation of the pore-forming effector protein gasdermin D by inflammatory caspases. Physical rupture of the cell causes release of the pro-inflammatory cytokines IL-1β and IL-18, alarmins and endogenous danger-associated molecular patterns, signifying the inflammatory potential of pyroptosis. Here, we describe the central role of inflammatory caspases and pyroptosis in mediating immunity to infection and clearance of pathogens.
Collapse
Affiliation(s)
- Si Ming Man
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Rajendra Karki
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | | |
Collapse
|
207
|
Differential roles of caspase-1 and caspase-11 in infection and inflammation. Sci Rep 2017; 7:45126. [PMID: 28345580 PMCID: PMC5366862 DOI: 10.1038/srep45126] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/16/2017] [Indexed: 02/07/2023] Open
Abstract
Caspase-1, also known as interleukin-1β (IL-1β)-converting enzyme (ICE), regulates antimicrobial host defense, tissue repair, tumorigenesis, metabolism and membrane biogenesis. On activation within an inflammasome complex, caspase-1 induces pyroptosis and converts pro-IL-1β and pro-IL-18 into their biologically active forms. “ICE−/−” or “Casp1−/−” mice generated using 129 embryonic stem cells carry a 129-associated inactivating passenger mutation on the caspase-11 locus, essentially making them deficient in both caspase-1 and caspase-11. The overlapping and unique functions of caspase-1 and caspase-11 are difficult to unravel without additional genetic tools. Here, we generated caspase-1–deficient mouse (Casp1Null) on the C57BL/6 J background that expressed caspase-11. Casp1Null cells did not release IL-1β and IL-18 in response to NLRC4 activators Salmonella Typhimurium and flagellin, canonical or non-canonical NLRP3 activators LPS and ATP, Escherichia coli, Citrobacter rodentium and transfection of LPS, AIM2 activators Francisella novicida, mouse cytomegalovirus and DNA, and the infectious agents Listeria monocytogenes and Aspergillus fumigatus. We further demonstrated that caspase-1 and caspase-11 differentially contributed to the host defense against A. fumigatus infection and to endotoxemia.
Collapse
|
208
|
O'Brien M, Moehring D, Muñoz-Planillo R, Núñez G, Callaway J, Ting J, Scurria M, Ugo T, Bernad L, Cali J, Lazar D. A bioluminescent caspase-1 activity assay rapidly monitors inflammasome activation in cells. J Immunol Methods 2017; 447:1-13. [PMID: 28268194 DOI: 10.1016/j.jim.2017.03.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 02/13/2017] [Accepted: 03/03/2017] [Indexed: 01/01/2023]
Abstract
Inflammasomes are protein complexes induced by diverse inflammatory stimuli that activate caspase-1, resulting in the processing and release of cytokines, IL-1β and IL-18, and pyroptosis, an immunogenic form of cell death. To provide a homogeneous method for detecting caspase-1 activity, we developed a bioluminescent, plate-based assay that combines a substrate, Z-WEHD-aminoluciferin, with a thermostable luciferase in an optimized lytic reagent added directly to cultured cells. Assay specificity for caspase-1 is conferred by inclusion of a proteasome inhibitor in the lytic reagent and by use of a caspase-1 inhibitor to confirm activity. This approach enables a specific and rapid determination of caspase-1 activation. Caspase-1 activity is stable in the reagent thereby providing assay convenience and flexibility. Using this assay system, caspase-1 activation has been determined in THP-1 cells following treatment with α-hemolysin, LPS, nigericin, gramicidin, MSU, R848, Pam3CSK4, and flagellin. Caspase-1 activation has also been demonstrated in treated J774A.1 mouse macrophages, bone marrow-derived macrophages (BMDMs) from mice, as well as in human primary monocytes. Caspase-1 activity was not detected in treated BMDMs derived from Casp1-/- mice, further confirming the specificity of the assay. Caspase-1 activity can be measured directly in cultured cells using the lytic reagent, or caspase-1 activity released into medium can be monitored by assay of transferred supernatant. The caspase-1 assay can be multiplexed with other assays to monitor additional parameters from the same cells, such as IL-1β release or cell death. The caspase-1 assay in combination with a sensitive real-time monitor of cell death allows one to accurately establish pyroptosis. This assay system provides a rapid, convenient, and flexible method to specifically and quantitatively monitor caspase-1 activation in cells in a plate-based format. This will allow a more efficient and effective assessment of inflammasome activation as well as enable high-throughput screening for inflammasome modulators.
Collapse
Affiliation(s)
- Martha O'Brien
- Promega Corporation, 2800 Woods Hollow Rd, Madison, WI 53711, USA.
| | | | - Raúl Muñoz-Planillo
- Dept. of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Gabriel Núñez
- Dept. of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Justin Callaway
- Dept. of Microbiology and Immunology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Jenny Ting
- Dept. of Microbiology and Immunology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Mike Scurria
- Promega Biosciences LLC, 277 Granada Dr, San Luis Obispo, CA 93401, USA
| | - Tim Ugo
- Promega Biosciences LLC, 277 Granada Dr, San Luis Obispo, CA 93401, USA
| | - Laurent Bernad
- Promega Biosciences LLC, 277 Granada Dr, San Luis Obispo, CA 93401, USA
| | - James Cali
- Promega Corporation, 2800 Woods Hollow Rd, Madison, WI 53711, USA
| | - Dan Lazar
- Promega Corporation, 2800 Woods Hollow Rd, Madison, WI 53711, USA
| |
Collapse
|
209
|
Jorgensen I, Rayamajhi M, Miao EA. Programmed cell death as a defence against infection. Nat Rev Immunol 2017; 17:151-164. [PMID: 28138137 DOI: 10.1038/nri.2016.147] [Citation(s) in RCA: 652] [Impact Index Per Article: 93.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Eukaryotic cells can die from physical trauma, which results in necrosis. Alternatively, they can die through programmed cell death upon the stimulation of specific signalling pathways. In this Review, we discuss the role of different cell death pathways in innate immune defence against bacterial and viral infection: apoptosis, necroptosis, pyroptosis and NETosis. We describe the interactions that interweave different programmed cell death pathways, which create complex signalling networks that cross-guard each other in the evolutionary 'arms race' with pathogens. Finally, we describe how the resulting cell corpses - apoptotic bodies, pore-induced intracellular traps (PITs) and neutrophil extracellular traps (NETs) - promote the clearance of infection.
Collapse
Affiliation(s)
- Ine Jorgensen
- Department of Immunology, Oslo University Hospital, Sognsvannsveien 20, Rikshospitalet 0372, Oslo, Norway
| | - Manira Rayamajhi
- Camargo Pharmaceutical Services, 2505 Meridian Parkway, Suite 175, Durham, North Carolina 27713, USA
| | - Edward A Miao
- Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, and Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| |
Collapse
|
210
|
de Torre-Minguela C, Mesa Del Castillo P, Pelegrín P. The NLRP3 and Pyrin Inflammasomes: Implications in the Pathophysiology of Autoinflammatory Diseases. Front Immunol 2017; 8:43. [PMID: 28191008 PMCID: PMC5271383 DOI: 10.3389/fimmu.2017.00043] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/11/2017] [Indexed: 12/28/2022] Open
Abstract
Inflammasomes are multiprotein complexes that critically control different aspects of innate and adaptive immunity. Among them we could highlight the release of pro-inflammatory cytokines that induce and maintain the inflammatory response. Usually, inflammasomes result from oligomerization of a nucleotide-binding domain-like receptor (NLR) after sensing different pathogenic or endogenous sterile dangerous signals; however, other proteins such as absent in melanoma 2, retinoic acid-inducible gene I, or pyrin could also form inflammasome platforms. Inflammasome oligomerization leads to caspase-1 activation and the processing and release of the pro-inflammatory cytokines, such as interleukin (IL)-1β and IL-18. Mutations in different inflammasomes are causative for multiple periodic hereditary syndromes or autoinflammatory diseases, characterized by acute systemic inflammatory flares not associated with infections, tumors, or autoimmunity. This review focuses on germline mutations that have been described in cryopyrin-associated periodic syndrome (CAPS) for NLRP3 or in familial Mediterranean fever (FMF) and pyrin-associated autoinflammation with neutrophilic dermatosis (PAAND) for MEFV. Besides the implication of inflammasomes in autoinflammatory syndromes, these molecular platforms are involved in the pathophysiology of different illnesses, including chronic inflammatory diseases, degenerative processes, fibrosis, or metabolic diseases. Therefore, drug development targeting inflammasome activation is a promising field in expansion.
Collapse
Affiliation(s)
- Carlos de Torre-Minguela
- Unidad de Inflamación Molecular, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIB-Arrixaca), CIBERehd, Hospital Clínico Universitario Virgen de la Arrixaca , Murcia , Spain
| | - Pablo Mesa Del Castillo
- Unidad de Inflamación Molecular, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIB-Arrixaca), CIBERehd, Hospital Clínico Universitario Virgen de la Arrixaca, Murcia, Spain; Unidad de Reumatología Pediátrica, Hospital Clínico Universitario Virgen de la Arrixaca, Murcia, Spain
| | - Pablo Pelegrín
- Unidad de Inflamación Molecular, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIB-Arrixaca), CIBERehd, Hospital Clínico Universitario Virgen de la Arrixaca , Murcia , Spain
| |
Collapse
|
211
|
Alternative inflammasome activation enables IL-1β release from living cells. Curr Opin Immunol 2016; 44:7-13. [PMID: 27842238 DOI: 10.1016/j.coi.2016.10.007] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 10/28/2016] [Indexed: 12/11/2022]
Abstract
Classical modes of NLRP3 activation entail a priming step that enables its activation (signal 1) and a potassium efflux-dependent activation signal (signal 2) that triggers pyroptosome formation and pyroptosis, a lytic cell death necessary for IL-1β release. Opposing to that, human monocytes engage an alternative NLRP3 inflammasome pathway in response to LPS that proceeds in the absence of signal 2 activation and enables IL-1β secretion without pyroptosis. This specifically relies on Caspase-8 to propagate signaling to NLRP3, leading to inflammasome activation in absence of pyroptosome formation. Here, we summarize the current knowledge about alternative inflammasome activation, discuss potential extensions of this signaling entity beyond LPS-dependent activation, speculate about its role in tissue homeostasis and sterile inflammation and highlight the implications of pyroptosis-independent IL-1β secretion.
Collapse
|
212
|
Bliss-Moreau M, Chen AA, D'Cruz AA, Croker BA. A motive for killing: effector functions of regulated lytic cell death. Immunol Cell Biol 2016; 95:146-151. [PMID: 27826146 DOI: 10.1038/icb.2016.113] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 11/03/2016] [Accepted: 11/04/2016] [Indexed: 12/23/2022]
Abstract
Immunological responses activated by pathogen recognition come in many guises. The proliferation, differentiation and recruitment of immune cells, and the production of inflammatory cytokines and chemokines are central to lifelong immunity. Cell death serves as a key function in the resolution of innate and adaptive immune responses. It also coordinates cell-intrinsic effector functions to restrict infection. Necrosis was formally considered a passive form of cell death or a consequence of pathogen virulence factor expression, and necrotic tissue is frequently associated with infection. However, there is now emerging evidence that points to a role for regulated forms of necrosis, such as pyroptosis and necroptosis, driving inflammation and shaping the immune response.
Collapse
Affiliation(s)
- Meghan Bliss-Moreau
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA.,Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Alyce A Chen
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA.,Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Akshay A D'Cruz
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA.,Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Ben A Croker
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA.,Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
213
|
Yu X, Wang Y, Lin J, Hu Y, Kawai T, Taubman MA, Han X. Lipopolysaccharides-Induced Suppression of Innate-Like B Cell Apoptosis Is Enhanced by CpG Oligodeoxynucleotide and Requires Toll-Like Receptors 2 and 4. PLoS One 2016; 11:e0165862. [PMID: 27812176 PMCID: PMC5094738 DOI: 10.1371/journal.pone.0165862] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 10/19/2016] [Indexed: 12/30/2022] Open
Abstract
Innate-like B lymphocytes play an important role in innate immunity in periodontal disease through Toll-like receptor (TLR) signaling. However, it is unknown how innate-like B cell apoptosis is affected by the periodontal infection-associated innate signals. This study is to determine the effects of two major TLR ligands, lipopolysaccharide (LPS) and CpG-oligodeoxynucleotides (CpG-ODN), on innate-like B cell apoptosis. Spleen B cells were isolated from wild type (WT), TLR2 knockout (KO) and TLR4 KO mice and cultured with E. coli LPS alone, P. gingivalis LPS alone, or combined with CpG-ODN for 2 days. B cell apoptosis and expressions of specific apoptosis-related genes were analyzed by flow cytometry and real-time PCR respectively. P. gingivalis LPS, but not E. coli LPS, reduced the percentage of AnnexinV+/7-AAD- cells within IgMhighCD23lowCD43-CD93- marginal zone (MZ) B cell sub-population and IgMhighCD23lowCD43+CD93+ innate response activator (IRA) B cell sub-population in WT but not TLR2KO or TLR4KO mice. CpG-ODN combined with P. gingivalis LPS further reduced the percentage of AnnexinV+/7-AAD- cells within MZ B cells and IRA B cells in WT but not TLR2 KO or TLR4 KO mice. Pro-apoptotic CASP4, CASP9 and Dapk1 were significantly down-regulated in P. gingivalis LPS- and CpG-ODN-treated B cells from WT but not TLR2 KO or TLR4 KO mice. Anti-apoptotic IL-10 was significantly up-regulated in P. gingivalis LPS- and CpG-ODN-treated B cells from WT and TLR2 KO but not TLR4 KO mice. These results suggested that both TLR2 and TLR4 signaling are required for P. gingivalis LPS-induced, CpG-ODN-enhanced suppression of innate-like B cell apoptosis.
Collapse
Affiliation(s)
- Xiaoqian Yu
- The Forsyth Institute, Department of Immunology and Infectious Diseases, Cambridge, MA, United States of America
- Peking University School and Hospital of Stomatology, Department of Periodontology, Beijing, China
| | - Yuhua Wang
- The Forsyth Institute, Department of Immunology and Infectious Diseases, Cambridge, MA, United States of America
- Ninth People’s Hospital, College of Stomatology, Shanghai JiaoTong University School of Medicine, Department of Prosthodontics, Shanghai Key laboratory, Shanghai, China
| | - Jiang Lin
- The Forsyth Institute, Department of Immunology and Infectious Diseases, Cambridge, MA, United States of America
- The Fourth Hospital of Harbin Medical University, Department of stomatology, Harbin, China
| | - Yang Hu
- The Forsyth Institute, Department of Immunology and Infectious Diseases, Cambridge, MA, United States of America
| | - Toshihisa Kawai
- The Forsyth Institute, Department of Immunology and Infectious Diseases, Cambridge, MA, United States of America
| | - Martin A. Taubman
- The Forsyth Institute, Department of Immunology and Infectious Diseases, Cambridge, MA, United States of America
| | - Xiaozhe Han
- The Forsyth Institute, Department of Immunology and Infectious Diseases, Cambridge, MA, United States of America
- * E-mail:
| |
Collapse
|
214
|
Pillon NJ, Chan KL, Zhang S, Mejdani M, Jacobson MR, Ducos A, Bilan PJ, Niu W, Klip A. Saturated fatty acids activate caspase-4/5 in human monocytes, triggering IL-1β and IL-18 release. Am J Physiol Endocrinol Metab 2016; 311:E825-E835. [PMID: 27624102 DOI: 10.1152/ajpendo.00296.2016] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/11/2016] [Indexed: 12/14/2022]
Abstract
Obesity is associated with metabolic tissue infiltration by monocyte-derived macrophages. Saturated fatty acids contribute to proinflammatory gene induction in tissue-embedded immune cells. However, it is unknown how circulating monocytes, the macrophage precursors, react to high-fat environments. In macrophages, saturated fatty acids activate inflammatory pathways and, notably, prime caspase-associated inflammasomes. Inflammasome-activated IL-1β contributes to type 2 diabetes. We hypothesized that 1) human monocytes from obese patients show caspase activation, and 2) fatty acids trigger this response and consequent release of IL-1β/IL-18. Human peripheral blood monocytes were sorted by flow cytometry, and caspase activity was measured with a FLICA dye-based assay. Blood monocytes from obese individuals exhibited elevated caspase activity. To explore the nature and consequence of this activity, human THP1 monocytes were exposed to saturated or unsaturated fatty acids. Caspase activity was revealed by isoform-specific cleavage and enzymatic activity; cytokine expression/release was measured by qPCR and ELISA. Palmitate, but not palmitoleate, increased caspase activity in parallel to the release of IL-1β and IL-18. Palmitate induced eventual monocyte cell death with features of pyroptosis (an inflammation-linked cell death program involving caspase-4/5), scored through LDH release, vital dye influx, cell volume changes, and nuclear morphology. Notably, selective gene silencing or inhibition of caspase-4/5 reduced palmitate-induced release of IL-1β and IL-18. In summary, monocytes from obese individuals present elevated caspase activity. Mechanistically, palmitate activates a pyroptotic program in monocytes through caspase-4/5, causing inflammatory cytokine release, additional to inflammasomes. These caspases represent potential, novel, therapeutic targets to taper obesity-associated inflammation.
Collapse
Affiliation(s)
- Nicolas J Pillon
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Kenny L Chan
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Shitian Zhang
- Department of Immunology, Key Laboratory of Immuno Microenvironment and Disease of the Educational Ministry of China, Tianjin Medical University, Tianjin, China; and
| | - Marios Mejdani
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Maya R Jacobson
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Alexandre Ducos
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Philip J Bilan
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Wenyan Niu
- Department of Immunology, Key Laboratory of Immuno Microenvironment and Disease of the Educational Ministry of China, Tianjin Medical University, Tianjin, China; and
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Amira Klip
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada;
| |
Collapse
|
215
|
Kajiwara Y, McKenzie A, Dorr N, Gama Sosa MA, Elder G, Schmeidler J, Dickstein DL, Bozdagi O, Zhang B, Buxbaum JD. The human-specific CASP4 gene product contributes to Alzheimer-related synaptic and behavioural deficits. Hum Mol Genet 2016; 25:4315-4327. [PMID: 27516385 DOI: 10.1093/hmg/ddw265] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 06/09/2016] [Accepted: 07/28/2016] [Indexed: 12/13/2022] Open
Abstract
Recent studies have indicated that innate immune signalling molecules are involved in late-onset Alzheimer's disease (LOAD) risk. Amyloid beta (Aβ) accumulates in AD brain, and has been proposed to act as a trigger of innate immune responses. Caspase-4 is an important part of the innate immune response. We recently characterized transgenic mice carrying human CASP4, and observed that the mice manifested profound innate immune responses to lipopolysaccharide (LPS). Since these inflammatory processes are important in the aetiology of AD, we have now analysed the correlation of expression of caspase-4 in human brain with AD risk genes, and studied caspase-4 effects on AD-related phenotypes in APPswe/PS1deltaE9 (APP/PS1) mice. We observed that the expression of caspase-4 was strongly correlated with AD risk genes including TYROBP, TREM2, CR1, PSEN1, MS4A4A and MS4A6A in LOAD brains. Caspase-4 expression was upregulated in CASP4/APP/PS1 mice in a region-specific manner, including hippocampus and prefrontal cortex. In APP/PS1 mice, caspase-4 expression led to impairments in the reversal phase of a Barnes maze task and in hippocampal synaptic plasticity, without affecting soluble or aggregated Aβ levels. Caspase-4 was expressed predominantly in microglial cells, and in the presence of CASP4, more microglia were clustered around amyloid plaques. Furthermore, our data indicated that caspase-4 modulates microglial cells in a manner that increases proinflammatory processes. We propose that microglial caspase-4 expression contributes to the cognitive impairments in AD, and that further study of caspase-4 will enhance our understanding of AD pathogenesis and may lead to novel therapeutic targets in AD.
Collapse
Affiliation(s)
| | - Andrew McKenzie
- Department of Genetics and Genomic Sciences.,Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, NY, USA
| | | | | | - Gregory Elder
- Department of Psychiatry.,Neurology Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, NY, USA.,Department of Neurology
| | | | - Dara L Dickstein
- Department of Neuroscience.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Bin Zhang
- Department of Genetics and Genomic Sciences.,Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, NY, USA
| | - Joseph D Buxbaum
- Department of Psychiatry .,Department of Genetics and Genomic Sciences.,Department of Neuroscience.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| |
Collapse
|
216
|
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.
Collapse
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
| |
Collapse
|
217
|
Abstract
Inflammasomes are multiprotein signalling platforms that control the inflammatory response and coordinate antimicrobial host defences. They are assembled by pattern-recognition receptors following the detection of pathogenic microorganisms and danger signals in the cytosol of host cells, and they activate inflammatory caspases to produce cytokines and to induce pyroptotic cell death. The clinical importance of inflammasomes reaches beyond infectious disease, as dysregulated inflammasome activity is associated with numerous hereditary and acquired inflammatory disorders. In this Review, we discuss the recent developments in inflammasome research with a focus on the molecular mechanisms that govern inflammasome assembly, signalling and regulation.
Collapse
Affiliation(s)
- Petr Broz
- Focal Area Infection Biology, Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| | - Vishva M Dixit
- Genentech Inc., South San Francisco, California 94080, USA
| |
Collapse
|
218
|
Arbore G, Kemper C. A novel "complement-metabolism-inflammasome axis" as a key regulator of immune cell effector function. Eur J Immunol 2016; 46:1563-73. [PMID: 27184294 PMCID: PMC5025719 DOI: 10.1002/eji.201546131] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 04/27/2016] [Accepted: 05/13/2016] [Indexed: 12/20/2022]
Abstract
The inflammasomes are intracellular multiprotein complexes that induce and regulate the generation of the key pro‐inflammatory cytokines IL‐1β and IL‐18 in response to infectious microbes and cellular stress. The activation of inflammasomes involves several upstream signals including classic pattern or danger recognition systems such as the TLRs. Recently, however, the activation of complement receptors, such as the anaphylatoxin C3a and C5a receptors and the complement regulator CD46, in conjunction with the sensing of cell metabolic changes, for instance increased amino acid influx and glycolysis (via mTORC1), have emerged as additional critical activators of the inflammasome. This review summarizes recent advances in our knowledge about complement‐mediated inflammasome activation, with a specific focus on a novel “complement – metabolism – NLRP3 inflammasome axis.”
Collapse
Affiliation(s)
- Giuseppina Arbore
- MRC Centre for Transplantation, Division of Transplant Immunology and Mucosal Biology, King's College London, London, UK
| | - Claudia Kemper
- MRC Centre for Transplantation, Division of Transplant Immunology and Mucosal Biology, King's College London, London, UK.,Laboratory of Molecular Immunology and the Immunology Center, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD, USA
| |
Collapse
|
219
|
de Vasconcelos NM, Van Opdenbosch N, Lamkanfi M. Inflammasomes as polyvalent cell death platforms. Cell Mol Life Sci 2016; 73:2335-47. [PMID: 27048821 PMCID: PMC11108487 DOI: 10.1007/s00018-016-2204-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 03/18/2016] [Indexed: 02/07/2023]
Abstract
Inflammasomes are multi-protein platforms that are organized in the cytosol to cope with pathogens and cellular stress. The pattern recognition receptors NLRP1, NLRP3, NLRC4, AIM2 and Pyrin all assemble canonical platforms for caspase-1 activation, while caspase-11-dependent inflammasomes respond to intracellular Gram-negative pathogens. Inflammasomes are chiefly known for their roles in maturation and secretion of the inflammatory cytokines interleukin-(IL)1β and IL18, but they can also induce regulated cell death. Activation of caspases 1 and 11 in myeloid cells can trigger pyroptosis, a lytic and inflammatory cell death mode. Pyroptosis has been implicated in secretion of IL1β, IL18 and intracellular alarmins. Akin to these factors, it may have beneficial roles in controlling pathogen replication, but become detrimental in the context of chronic autoinflammatory diseases. Inflammasomes are increasingly implicated in induction of additional regulated cell death modes such as pyronecrosis and apoptosis. In this review, we overview recent advances in inflammasome-associated cell death research, illustrating the polyvalent roles of these macromolecular platforms in regulated cell death signaling.
Collapse
Affiliation(s)
- Nathalia M de Vasconcelos
- NOD-like Receptor and Inflammasome Laboratory, Inflammation Research Center, VIB, Technologiepark 927, B-9052, Zwijnaarde, Belgium
- Department of Internal Medicine, Ghent University, B-9000, Ghent, Belgium
| | - Nina Van Opdenbosch
- NOD-like Receptor and Inflammasome Laboratory, Inflammation Research Center, VIB, Technologiepark 927, B-9052, Zwijnaarde, Belgium
- Department of Internal Medicine, Ghent University, B-9000, Ghent, Belgium
| | - Mohamed Lamkanfi
- NOD-like Receptor and Inflammasome Laboratory, Inflammation Research Center, VIB, Technologiepark 927, B-9052, Zwijnaarde, Belgium.
- Department of Internal Medicine, Ghent University, B-9000, Ghent, Belgium.
| |
Collapse
|
220
|
Interferons and inflammasomes: Cooperation and counterregulation in disease. J Allergy Clin Immunol 2016; 138:37-46. [PMID: 27373324 DOI: 10.1016/j.jaci.2016.05.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 05/02/2016] [Accepted: 05/03/2016] [Indexed: 02/07/2023]
Abstract
Interferons and the IL-1 family of cytokines have important roles in host defense against invading viruses and bacteria. Inflammasomes, multimeric cytosolic sensors of infection, are required for IL-1β and IL-18 processing and release. Interferons, IL-1β, and IL-18 are also implicated in autoimmune disease and chronic inflammation. Although independent but complementary pathways induce these cytokine subsets during infection, in some circumstances the cross-talk between these key inflammatory mediators is a particular requirement for effective host defense. In this review we will summarize recent discoveries concerning the potentiation of inflammasome responses by type I interferons, particularly in patients with gram-negative bacterial infections, and reflect on the molecular mechanisms of IFN-β's immunosuppressive effects through modulation of inflammasome and IL-1β signaling in patients with tuberculosis and multiple sclerosis.
Collapse
|
221
|
García de la Cadena S, Massieu L. Caspases and their role in inflammation and ischemic neuronal death. Focus on caspase-12. Apoptosis 2016; 21:763-77. [DOI: 10.1007/s10495-016-1247-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
222
|
Human Monocytes Engage an Alternative Inflammasome Pathway. Immunity 2016; 44:833-46. [PMID: 27037191 DOI: 10.1016/j.immuni.2016.01.012] [Citation(s) in RCA: 558] [Impact Index Per Article: 69.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 12/04/2015] [Accepted: 01/20/2016] [Indexed: 01/03/2023]
Abstract
Interleukin-1β (IL-1β) is a cytokine whose bioactivity is controlled by activation of the inflammasome. However, in response to lipopolysaccharide, human monocytes secrete IL-1β independently of classical inflammasome stimuli. Here, we report that this constituted a species-specific response that is not observed in the murine system. Indeed, in human monocytes, lipopolysaccharide triggered an "alternative inflammasome" that relied on NLRP3-ASC-caspase-1 signaling, yet was devoid of any classical inflammasome characteristics including pyroptosome formation, pyroptosis induction, and K(+) efflux dependency. Genetic dissection of the underlying signaling pathway in a monocyte transdifferentiation system revealed that alternative inflammasome activation was propagated by TLR4-TRIF-RIPK1-FADD-CASP8 signaling upstream of NLRP3. Importantly, involvement of this signaling cascade was limited to alternative inflammasome activation and did not extend to classical NLRP3 activation. Because alternative inflammasome activation embraces both sensitivity and promiscuity of TLR4, we propose a pivotal role for this signaling cascade in TLR4-driven, IL-1β-mediated immune responses and immunopathology in humans.
Collapse
|
223
|
Abstract
The complementary actions of the innate and adaptive immune systems often provide effective host defense against microbial pathogens and harmful environmental agents. Germline-encoded pattern recognition receptors (PRRs) endow the innate immune system with the ability to detect and mount a rapid response against a given threat. Members of several intracellular PRR families, including the nucleotide-binding domain and leucine-rich repeat containing receptors (NLRs), the AIM2-like receptors (ALRs), and the tripartite motif-containing (TRIM) protein Pyrin/TRIM20, nucleate the formation of inflammasomes. These cytosolic scaffolds serve to recruit and oligomerize the cysteine protease caspase-1 in filaments that promote its proximity-induced autoactivation. This oligomerization occurs either directly or indirectly through intervention of the bipartite adaptor protein ASC, apoptosis-associated speck-like protein containing a caspase recruitment domain (CARD), which is needed for the domain interaction. Caspase-1 cleaves the precursors of the inflammatory cytokines interleukin (IL)-1β and IL-18 and triggers their release into the extracellular space, where they act on effector cells to promote both local and systemic immune responses. Additionally, inflammasome activation gives rise to a lytic mode of cell death, named pyroptosis, which is thought to contribute to initial host defense against infection by eliminating replication niches of intracellular pathogens and exposing them to the immune system. Inflammasome-induced host defense responses are the subject of intense investigation, and understanding their physiological roles during infection and the regulatory circuits that are involved is becoming increasingly detailed. Here, we discuss current understanding of the activation mechanisms and biological outcomes of inflammasome activation.
Collapse
Affiliation(s)
- Hanne Dubois
- NOD-like Receptor and Inflammasome Laboratory, Inflammation Research Center, VIB, 9052, Zwijnaarde, Belgium.,Department of Internal Medicine, Ghent University, 9000, Ghent, Belgium
| | - Andy Wullaert
- NOD-like Receptor and Inflammasome Laboratory, Inflammation Research Center, VIB, 9052, Zwijnaarde, Belgium.,Department of Internal Medicine, Ghent University, 9000, Ghent, Belgium
| | - Mohamed Lamkanfi
- NOD-like Receptor and Inflammasome Laboratory, Inflammation Research Center, VIB, 9052, Zwijnaarde, Belgium. .,Department of Internal Medicine, Ghent University, 9000, Ghent, Belgium.
| |
Collapse
|
224
|
Deng Q, Wang Y, Zhang Y, Li M, Li D, Huang X, Wu Y, Pu J, Wu M. Pseudomonas aeruginosa Triggers Macrophage Autophagy To Escape Intracellular Killing by Activation of the NLRP3 Inflammasome. Infect Immun 2016; 84:56-66. [PMID: 26467446 PMCID: PMC4694000 DOI: 10.1128/iai.00945-15] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/12/2015] [Indexed: 02/07/2023] Open
Abstract
Assembly of the inflammasome has recently been identified to be a critical event in the initiation of inflammation. However, its role in bacterial killing remains unclear. Our study demonstrates that Pseudomonas aeruginosa infection induces the assembly of the NLRP3 inflammasome and the sequential secretion of caspase1 and interleukin-1β (IL-1β) in human macrophages. More importantly, activation of the NLRP3 inflammasome reduces the killing of P. aeruginosa in human macrophages, without affecting the generation of antimicrobial peptides, reactive oxygen species, and nitric oxide. In addition, our results demonstrate that P. aeruginosa infection increases the amount of the LC3-II protein and triggers the formation of autophagosomes in human macrophages. The P. aeruginosa-induced autophagy was enhanced by overexpression of NLRP3, ASC, or caspase1 but was reduced by knockdown of these core molecules of the NLRP3 inflammasome. Treatment with IL-1β enhanced autophagy in human macrophages. More importantly, IL-1β decreased the macrophage-mediated killing of P. aeruginosa, whereas knockdown of ATG7 or Beclin1 restored the IL-1β-mediated suppression of bacterial killing. Collectively, our study explores a novel mechanism employed by P. aeruginosa to escape from phagocyte killing and may provide a better understanding of the interaction between P. aeruginosa and host immune cells, including macrophages.
Collapse
Affiliation(s)
- Qiuchan Deng
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Yi Wang
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Yuanqing Zhang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Meiyu Li
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Dandan Li
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Xi Huang
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Yongjian Wu
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Jieying Pu
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Minhao Wu
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Institute of Tuberculosis Control, Sun Yat-sen University, Guangzhou, China Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| |
Collapse
|
225
|
Converging roles of caspases in inflammasome activation, cell death and innate immunity. Nat Rev Immunol 2015; 16:7-21. [PMID: 26655628 DOI: 10.1038/nri.2015.7] [Citation(s) in RCA: 455] [Impact Index Per Article: 50.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Inflammatory and apoptotic caspases are central players in inflammation and apoptosis, respectively. However, recent studies have revealed that these caspases have functions beyond their established roles. In addition to mediating cleavage of the inflammasome-associated cytokines interleukin-1β (IL-1β) and IL-18, inflammatory caspases modulate distinct forms of programmed cell death and coordinate cell-autonomous immunity and other fundamental cellular processes. Certain apoptotic caspases assemble structurally diverse and dynamic complexes that direct inflammasome and interferon responses to fine-tune inflammation. In this Review, we discuss the expanding and interconnected roles of caspases that highlight new aspects of this family of cysteine proteases in innate immunity.
Collapse
|
226
|
Shao BZ, Xu ZQ, Han BZ, Su DF, Liu C. NLRP3 inflammasome and its inhibitors: a review. Front Pharmacol 2015; 6:262. [PMID: 26594174 PMCID: PMC4633676 DOI: 10.3389/fphar.2015.00262] [Citation(s) in RCA: 585] [Impact Index Per Article: 65.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 10/22/2015] [Indexed: 01/04/2023] Open
Abstract
Inflammasomes are newly recognized, vital players in innate immunity. The best characterized is the NLRP3 inflammasome, so-called because the NLRP3 protein in the complex belongs to the family of nucleotide-binding and oligomerization domain-like receptors (NLRs) and is also known as “pyrin domain-containing protein 3”. The NLRP3 inflammasome is associated with onset and progression of various diseases, including metabolic disorders, multiple sclerosis, inflammatory bowel disease, cryopyrin-associated periodic fever syndrome, as well as other auto-immune and auto-inflammatory diseases. Several NLRP3 inflammasome inhibitors have been described, some of which show promise in the clinic. The present review will describe the structure and mechanisms of activation of the NLRP3 inflammasome, its association with various auto-immune and auto-inflammatory diseases, and the state of research into NLRP3 inflammasome inhibitors.
Collapse
Affiliation(s)
- Bo-Zong Shao
- Department of Pharmacology, Second Military Medical University Shanghai, China
| | - Zhe-Qi Xu
- Department of Pharmacology, Second Military Medical University Shanghai, China
| | - Bin-Ze Han
- Department of Pharmacology, Second Military Medical University Shanghai, China
| | - Ding-Feng Su
- Department of Pharmacology, Second Military Medical University Shanghai, China
| | - Chong Liu
- Department of Pharmacology, Second Military Medical University Shanghai, China
| |
Collapse
|
227
|
Rivers-Auty J, Brough D. Potassium efflux fires the canon: Potassium efflux as a common trigger for canonical and noncanonical NLRP3 pathways. Eur J Immunol 2015; 45:2758-61. [PMID: 26332156 DOI: 10.1002/eji.201545958] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 08/12/2015] [Accepted: 08/21/2015] [Indexed: 01/10/2023]
Abstract
Murine caspase-11 and its human orthologues, caspase-4 and caspase-5, activate an inflammatory response following cytoplasmic recognition of cell wall constituents from Gram-negative bacteria, such as LPS. This inflammatory response involves pyroptotic cell death and the concomitant release of IL-1α, as well as the production of IL-1β and IL-18 through the noncanonical NLR family, pyrin domain containing 3 (NLRP3) pathway. This commentary discusses three papers in this issue of the European Journal of Immunology that advance our understanding of the roles of caspase-11, -4, and -5 in the noncanonical pathway. By utilizing the new gene editing technique, clustered regularly interspaced short palindromic repeats (CRISPR), as well as sensitive cell imaging techniques, these papers establish that cytoplasmic LPS-dependent IL-1β production requires the NLRP3 inflammasome and that its activation is dependent on K(+) efflux, whereas IL-1α release and pyroptotic cell death pathways are NLRP3-independent. These findings expand on previous research implicating K(+) efflux as the principal trigger for NLRP3 activation and suggest that canonical and noncanonical NLRP3 pathways are not as dissimilar as first thought.
Collapse
Affiliation(s)
- Jack Rivers-Auty
- Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - David Brough
- Faculty of Life Sciences, University of Manchester, Manchester, UK
| |
Collapse
|