1
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Zhang Y, Liang S, Deng Z, Zhao Z, Han X. High-glucose conditions attenuate the response of macrophages to Legionella pneumophila infection by inhibiting NOD1 and MAPK signaling. Int Immunopharmacol 2024; 134:112254. [PMID: 38749333 DOI: 10.1016/j.intimp.2024.112254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 05/08/2024] [Accepted: 05/09/2024] [Indexed: 06/03/2024]
Abstract
BACKGROUND Patients with diabetes are particularly susceptible to Legionella pneumophila (LP) infection, but the exact pathogenesis of LP infection in diabetic patients is still not fully understood. Herein, we investigated the effect of diabetes on immune function during LP infection in vitro and in vivo. METHODS The time course of LP infection in macrophages under normal and high-glucose (HG) conditions was examined in vitro. Western blot was used to determine nucleotide-binding oligomerization domain 1 (NOD1), kinase 1/2 (ERK1/2), mitogen-activated protein kinase p38 (MAPK p38), and c-Jun N-terminal kinases (JNK). Enzyme-linked immunosorbent assay (ELISA) was used to assess the secretion of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Cell Counting Kit-8 (CCK8) assay assessed U937 cell viability after treating cells with different concentrations of high sugar medium and ML130 (NOD1 inhibitor). For the in vivo study, normal and streptozocin-induced diabetic guinea pigs were infected with LP for 6, 24, and 72 h, after which NOD1, MAPK-related signals, TNF-α, and IL-6 expression in lung tissues were assessed using immunohistochemistry, western blot, and RT-PCR. RESULTS HG attenuated the upregulation of NOD1 expression and reduced TNF-α and IL-6 secretion caused by LP compared with LP-infected cells exposed to normal glucose levels (all p < 0.05). In diabetic guinea pigs, HG inhibited the upregulation of NOD1 expression in lung tissues and the activation of p38, ERK1/2, and cJNK caused by LP infection compared to control pigs (all p < 0.05). CONCLUSION HG attenuates the response of macrophages to LP infection by inhibiting NOD1 upregulation and the activation of MAPK signaling.
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Affiliation(s)
- Yuting Zhang
- Department of Pulmonary and Critical Care Medicine, Shengjing Hospital of China Medical University, Liaoning Province, Shenyang 110001, PR China
| | - Sicong Liang
- Department of Pulmonary and Critical Care Medicine, Shengjing Hospital of China Medical University, Liaoning Province, Shenyang 110001, PR China
| | - Ze Deng
- Department of Pulmonary and Critical Care Medicine, Shengjing Hospital of China Medical University, Liaoning Province, Shenyang 110001, PR China
| | - Zirui Zhao
- Department of Pulmonary and Critical Care Medicine, Shengjing Hospital of China Medical University, Liaoning Province, Shenyang 110001, PR China
| | - Xu Han
- Department of Emergency, Shengjing Hospital of China Medical University, Liaoning Province, Shenyang 110001, PR China.
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Yao J, Sterling K, Wang Z, Zhang Y, Song W. The role of inflammasomes in human diseases and their potential as therapeutic targets. Signal Transduct Target Ther 2024; 9:10. [PMID: 38177104 PMCID: PMC10766654 DOI: 10.1038/s41392-023-01687-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 09/18/2023] [Accepted: 10/13/2023] [Indexed: 01/06/2024] Open
Abstract
Inflammasomes are large protein complexes that play a major role in sensing inflammatory signals and triggering the innate immune response. Each inflammasome complex has three major components: an upstream sensor molecule that is connected to a downstream effector protein such as caspase-1 through the adapter protein ASC. Inflammasome formation typically occurs in response to infectious agents or cellular damage. The active inflammasome then triggers caspase-1 activation, followed by the secretion of pro-inflammatory cytokines and pyroptotic cell death. Aberrant inflammasome activation and activity contribute to the development of diabetes, cancer, and several cardiovascular and neurodegenerative disorders. As a result, recent research has increasingly focused on investigating the mechanisms that regulate inflammasome assembly and activation, as well as the potential of targeting inflammasomes to treat various diseases. Multiple clinical trials are currently underway to evaluate the therapeutic potential of several distinct inflammasome-targeting therapies. Therefore, understanding how different inflammasomes contribute to disease pathology may have significant implications for developing novel therapeutic strategies. In this article, we provide a summary of the biological and pathological roles of inflammasomes in health and disease. We also highlight key evidence that suggests targeting inflammasomes could be a novel strategy for developing new disease-modifying therapies that may be effective in several conditions.
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Affiliation(s)
- Jing Yao
- The National Clinical Research Center for Geriatric Disease, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China
| | - Keenan Sterling
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, The University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Zhe Wang
- The National Clinical Research Center for Geriatric Disease, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China
| | - Yun Zhang
- The National Clinical Research Center for Geriatric Disease, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China.
- Key Laboratory of Neurodegenerative Diseases, Ministry of Education, Beijing, P.R. China.
| | - Weihong Song
- The National Clinical Research Center for Geriatric Disease, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China.
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, The University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada.
- Zhejiang Clinical Research Center for Mental Disorders, Key Laboratory of Alzheimer's Disease of Zhejiang Province, School of Mental Health and The Affiliated Kangning Hospital, Institute of Aging, Wenzhou Medical University, Wenzhou, Zhejiang, 325000, China.
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Wenzhou, Zhejiang, 325000, China.
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3
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Matico RE, Yu X, Miller R, Somani S, Ricketts MD, Kumar N, Steele RA, Medley Q, Berger S, Faustin B, Sharma S. Structural basis of the human NAIP/NLRC4 inflammasome assembly and pathogen sensing. Nat Struct Mol Biol 2024; 31:82-91. [PMID: 38177670 PMCID: PMC10803261 DOI: 10.1038/s41594-023-01143-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 09/28/2023] [Indexed: 01/06/2024]
Abstract
The NLR family caspase activation and recruitment domain-containing 4 (NLRC4) inflammasome is a critical cytosolic innate immune machine formed upon the direct sensing of bacterial infection and in response to cell stress during sterile chronic inflammation. Despite its major role in instigating the subsequent host immune response, a more complete understanding of the molecular events in the formation of the NLRC4 inflammasome in humans is lacking. Here we identify Bacillus thailandensis type III secretion system needle protein (Needle) as a potent trigger of the human NLR family apoptosis inhibitory protein (NAIP)/NLRC4 inflammasome complex formation and determine its structural features by cryogenic electron microscopy. We also provide a detailed understanding of how type III secretion system pathogen components are sensed by human NAIP to form a cascade of NLRC4 protomer through a critical lasso-like motif, a 'lock-key' activation model and large structural rearrangement, ultimately forming the full human NLRC4 inflammasome. These results shed light on key regulatory mechanisms specific to the NLRC4 inflammasome assembly, and the innate immune modalities of pathogen sensing in humans.
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Affiliation(s)
- Rosalie E Matico
- Structural and Protein Sciences, Johnson & Johnson Innovative Medicine, Spring House, PA, USA
| | - Xiaodi Yu
- Structural and Protein Sciences, Johnson & Johnson Innovative Medicine, Spring House, PA, USA.
| | - Robyn Miller
- Structural and Protein Sciences, Johnson & Johnson Innovative Medicine, Spring House, PA, USA
| | - Sandeep Somani
- In Silico Discovery Sciences, Johnson & Johnson Innovative Medicine, Spring House, PA, USA
| | - M Daniel Ricketts
- Structural and Protein Sciences, Johnson & Johnson Innovative Medicine, Spring House, PA, USA
| | - Nikit Kumar
- Structural and Protein Sciences, Johnson & Johnson Innovative Medicine, Spring House, PA, USA
| | - Ruth A Steele
- Structural and Protein Sciences, Johnson & Johnson Innovative Medicine, Spring House, PA, USA
| | - Quintus Medley
- Discovery Immunology, Johnson & Johnson Innovative Medicine, Cambridge, MA, USA
| | - Scott Berger
- Discovery Immunology, Johnson & Johnson Innovative Medicine, Spring House, PA, USA
| | - Benjamin Faustin
- Discovery Immunology, Johnson & Johnson Innovative Medicine, San Diego, CA, USA
| | - Sujata Sharma
- Structural and Protein Sciences, Johnson & Johnson Innovative Medicine, Spring House, PA, USA
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4
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Liu Y, Zhai H, Alemayehu H, Boulanger J, Hopkins LJ, Borgeaud AC, Heroven C, Howe JD, Leigh KE, Bryant CE, Modis Y. Cryo-electron tomography of NLRP3-activated ASC complexes reveals organelle co-localization. Nat Commun 2023; 14:7246. [PMID: 37945612 PMCID: PMC10636019 DOI: 10.1038/s41467-023-43180-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 11/02/2023] [Indexed: 11/12/2023] Open
Abstract
NLRP3 induces caspase-1-dependent pyroptotic cell death to drive inflammation. Aberrant activity of NLRP3 occurs in many human diseases. NLRP3 activation induces ASC polymerization into a single, micron-scale perinuclear punctum. Higher resolution imaging of this signaling platform is needed to understand how it induces pyroptosis. Here, we apply correlative cryo-light microscopy and cryo-electron tomography to visualize ASC/caspase-1 in NLRP3-activated cells. The puncta are composed of branched ASC filaments, with a tubular core formed by the pyrin domain. Ribosomes and Golgi-like or endosomal vesicles permeate the filament network, consistent with roles for these organelles in NLRP3 activation. Mitochondria are not associated with ASC but have outer-membrane discontinuities the same size as gasdermin D pores, consistent with our data showing gasdermin D associates with mitochondria and contributes to mitochondrial depolarization.
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Affiliation(s)
- Yangci Liu
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge, CB2 0AW, UK
| | - Haoming Zhai
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge, CB2 0AW, UK
| | - Helen Alemayehu
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge, CB2 0AW, UK
| | - Jérôme Boulanger
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Lee J Hopkins
- Department of Medicine, University of Cambridge, Box 157, Level 5, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 0ES, UK
- Wren Therapeutics, Clarendon House, Clarendon Road, Cambridge, CB2 8FH, UK
| | - Alicia C Borgeaud
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012, Bern, Switzerland
| | - Christina Heroven
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Division of Structural Biology, University of Oxford, Oxford, OX3 7BN, UK
| | - Jonathan D Howe
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Kendra E Leigh
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge, CB2 0AW, UK
| | - Clare E Bryant
- Department of Medicine, University of Cambridge, Box 157, Level 5, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK.
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 0ES, UK.
| | - Yorgo Modis
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge, CB2 0AW, UK.
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5
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Zhou Y, Yu S, Zhang W. NOD-like Receptor Signaling Pathway in Gastrointestinal Inflammatory Diseases and Cancers. Int J Mol Sci 2023; 24:14511. [PMID: 37833958 PMCID: PMC10572711 DOI: 10.3390/ijms241914511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/15/2023] [Accepted: 09/23/2023] [Indexed: 10/15/2023] Open
Abstract
Nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs) are intracellular proteins with a central role in innate and adaptive immunity. As a member of pattern recognition receptors (PRRs), NLRs sense specific pathogen-associated molecular patterns, trigger numerous signaling pathways and lead to the secretion of various cytokines. In recent years, cumulative studies have revealed the significant impacts of NLRs in gastrointestinal (GI) inflammatory diseases and cancers. Deciphering the role and molecular mechanism of the NLR signaling pathways may provide new opportunities for the development of therapeutic strategies related to GI inflammatory diseases and GI cancers. This review presents the structures and signaling pathways of NLRs, summarizes the recent advances regarding NLR signaling in GI inflammatory diseases and GI cancers and describes comprehensive therapeutic strategies based on this signaling pathway.
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Affiliation(s)
- Yujie Zhou
- School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China; (Y.Z.); (S.Y.)
| | - Songyan Yu
- School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China; (Y.Z.); (S.Y.)
| | - Wenyong Zhang
- School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China; (Y.Z.); (S.Y.)
- Key University Laboratory of Metabolism and Health of Guangdong, Southern University of Science and Technology, Shenzhen 518055, China
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6
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Egan MS, O’Rourke EA, Mageswaran SK, Zuo B, Martynyuk I, Demissie T, Hunter EN, Bass AR, Chang YW, Brodsky IE, Shin S. Inflammasomes primarily restrict cytosolic Salmonella replication within human macrophages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.17.549348. [PMID: 37503120 PMCID: PMC10370064 DOI: 10.1101/2023.07.17.549348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Salmonella enterica serovar Typhimurium is a facultative intracellular pathogen that utilizes its type III secretion systems (T3SSs) to inject virulence factors into the host cell and colonize the host. In turn, a subset of cytosolic immune receptors respond to T3SS ligands by forming multimeric signaling complexes called inflammasomes, which activate caspases that induce interleukin-1 (IL-1) family cytokine release and an inflammatory form of cell death called pyroptosis. Human macrophages mount a multifaceted inflammasome response to Salmonella infection that ultimately restricts intracellular bacterial replication. However, how inflammasomes restrict Salmonella replication remains unknown. We find that caspase-1 is essential for mediating inflammasome responses to Salmonella and subsequent restriction of bacterial replication within human macrophages, with caspase-4 contributing as well. We also demonstrate that the downstream pore-forming protein gasdermin D (GSDMD) and ninjurin-1 (NINJ1), a mediator of terminal cell lysis, play a role in controlling Salmonella replication in human macrophages. Notably, in the absence of inflammasome responses, we observed hyperreplication of Salmonella within the cytosol of infected cells, and we also observed increased bacterial replication within vacuoles, suggesting that inflammasomes control Salmonella replication primarily within the cytosol and also within vacuoles. These findings reveal that inflammatory caspases and pyroptotic factors mediate inflammasome responses that restrict the subcellular localization of intracellular Salmonella replication within human macrophages.
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Affiliation(s)
- Marisa S. Egan
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Emily A. O’Rourke
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Shrawan Kumar Mageswaran
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Biao Zuo
- Electron Microscopy Resource Laboratory, Department of Biochemistry & Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Inna Martynyuk
- Electron Microscopy Resource Laboratory, Department of Biochemistry & Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Tabitha Demissie
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Emma N. Hunter
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Antonia R. Bass
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Yi-Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Igor E. Brodsky
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA
| | - Sunny Shin
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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7
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Egan MS, Zhang J, Shin S. Human and mouse NAIP/NLRC4 inflammasome responses to bacterial infection. Curr Opin Microbiol 2023; 73:102298. [PMID: 37058933 PMCID: PMC10225321 DOI: 10.1016/j.mib.2023.102298] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 02/15/2023] [Accepted: 02/22/2023] [Indexed: 04/16/2023]
Abstract
Intracellular immune complexes known as inflammasomes sense breaches of cytosolic sanctity. Inflammasomes promote downstream proinflammatory events, including interleukin-1 (IL-1) family cytokine release and pyroptotic cell death. The nucleotide-binding leucine-rich repeat family, apoptosis inhibitory protein/nucleotide-binding leucine-rich repeat family, caspase recruitment domain (CARD) domain-containing protein 4 (NAIP/NLRC4) inflammasome is involved in a range of pathogenic and protective inflammatory processes in mammalian hosts. In particular, the NAIP/NLRC4 inflammasome responds to flagellin and components of the virulence-associated type III secretion (T3SS) apparatus in the host cytosol, thereby allowing it to be a critical mediator of host defense during bacterial infection. Notable species- and cell type-specific differences exist in NAIP/NLRC4 inflammasome responses to bacterial pathogens. With a focus on Salmonella enterica serovar Typhimurium as a model pathogen, we review differences between murine and human NAIP/NLRC4 inflammasome responses. Differences in NAIP/NLRC4 inflammasome responses across species and cell types may have arisen in part due to evolutionary pressures.
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Affiliation(s)
- Marisa S Egan
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jenna Zhang
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Sunny Shin
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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8
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Grayczyk JP, Egan MS, Liu L, Aunins E, Wynosky-Dolfi MA, Canna S, Minn AJ, Shin S, Brodsky IE. TLR priming licenses NAIP inflammasome activation by immunoevasive ligands. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.04.539437. [PMID: 37205371 PMCID: PMC10187295 DOI: 10.1101/2023.05.04.539437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
NLR family, apoptosis inhibitory proteins (NAIPs) detect bacterial flagellin and structurally related components of bacterial type III secretion systems (T3SS), and recruit NLR family, CARD domain containing protein 4 (NLRC4) and caspase-1 into an inflammasome complex that induces pyroptosis. NAIP/NLRC4 inflammasome assembly is initiated by the binding of a single NAIP to its cognate ligand, but a subset of bacterial flagellins or T3SS structural proteins are thought to evade NAIP/NLRC4 inflammasome sensing by not binding to their cognate NAIPs. Unlike other inflammasome components such as NLRP3, AIM2, or some NAIPs, NLRC4 is constitutively present in resting macrophages, and not thought to be regulated by inflammatory signals. Here, we demonstrate that Toll-like receptor (TLR) stimulation upregulates NLRC4 transcription and protein expression in murine macrophages, which licenses NAIP detection of evasive ligands. TLR-induced NLRC4 upregulation and NAIP detection of evasive ligands required p38 MAPK signaling. In contrast, TLR priming in human macrophages did not upregulate NLRC4 expression, and human macrophages remained unable to detect NAIP-evasive ligands even following priming. Critically, ectopic expression of either murine or human NLRC4 was sufficient to induce pyroptosis in response to immunoevasive NAIP ligands, indicating that increased levels of NLRC4 enable the NAIP/NLRC4 inflammasome to detect these normally evasive ligands. Altogether, our data reveal that TLR priming tunes the threshold for NAIP/NLRC4 inflammasome activation and enables inflammasome responses against immunoevasive or suboptimal NAIP ligands.
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Affiliation(s)
- James P Grayczyk
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Marisa S Egan
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Luying Liu
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Emily Aunins
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Meghan A Wynosky-Dolfi
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Scott Canna
- Department of Pediatrics, Division of Rheumatology, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Andy J Minn
- Department of Radiation Oncology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Parker Institute for Cancer Immunotherapy, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Mark Foundation Center for Immunotherapy, Immune Signaling, and Radiation, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Sunny Shin
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Igor E Brodsky
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
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9
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Lv X, Li S, Yu Y, Jin S, Zhang X, Li F. LvCD14L Acts as a Novel Pattern Recognition Receptor and a Regulator of the Toll Signaling Pathway in Shrimp. Int J Mol Sci 2023; 24:ijms24097770. [PMID: 37175476 PMCID: PMC10178686 DOI: 10.3390/ijms24097770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/14/2023] [Accepted: 04/19/2023] [Indexed: 05/15/2023] Open
Abstract
Leucine-rich repeat (LRR) is a structural motif has important recognition function in immune receptors, such as Tolls and NOD-like receptors (NLRs). The immune-related LRR proteins can be divided into two categories, LRR-containing proteins and LRR-only proteins. The latter contain LRR motifs while they are without other functional domains. However, the functional mechanisms of the LRR-only proteins were still unclear in invertebrates. Here, we identified a gene encoding a secretory LRR-only protein, which possessed similarity with vertebrate CD14 and was designated as LvCD14L, from the Pacific whiteleg shrimp Litopenaeus vannamei. Its transcripts in shrimp hemocytes were apparently responsive to the infection of Vibrio parahaemolyticus. Knockdown of LvCD14L with dsRNA resulted in significant increase of the viable bacteria in the hepatopancreas of shrimp upon V. parahaemolyticus infection. Further functional studies revealed that LvCD14L could bind to microorganisms' PAMPs, showed interaction with LvToll1 and LvToll2, and regulated the expression of LvDorsal and LvALF2 in hemocytes. These results suggest that LvCD14L functions as a pattern recognition receptor and activates the NF-κB pathway through interaction with LvTolls. The present study reveals a shrimp LvCD14L-Tolls-NF-κB signaling pathway like the CD14/TLR4/NF-κB signaling pathway in mammalians, which enriches the functional mechanism of secretory LRR-only immune receptors during pathogens infection in invertebrates.
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Affiliation(s)
- Xinjia Lv
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Shihao Li
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Yang Yu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Songjun Jin
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Xiaojun Zhang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Fuhua Li
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- The Innovation of Seed Design, Chinese Academy of Sciences, Wuhan 430072, China
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10
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Keestra-Gounder AM, Nagao PE. Inflammasome activation by Gram-positive bacteria: Mechanisms of activation and regulation. Front Immunol 2023; 14:1075834. [PMID: 36761775 PMCID: PMC9902775 DOI: 10.3389/fimmu.2023.1075834] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 01/06/2023] [Indexed: 01/26/2023] Open
Abstract
The inflammasomes are intracellular multimeric protein complexes consisting of an innate immune sensor, the adapter protein ASC and the inflammatory caspases-1 and/or -11 and are important for the host defense against pathogens. Activaton of the receptor leads to formation of the inflammasomes and subsequent processing and activation of caspase-1 that cleaves the proinflammatory cytokines IL-1β and IL-18. Active caspase-1, and in some instances caspase-11, cleaves gasdermin D that translocates to the cell membrane where it forms pores resulting in the cell death program called pyroptosis. Inflammasomes can detect a range of microbial ligands through direct interaction or indirectly through diverse cellular processes including changes in ion fluxes, production of reactive oxygen species and disruption of various host cell functions. In this review, we will focus on the NLRP3, NLRP6, NLRC4 and AIM2 inflammasomes and how they are activated and regulated during infections with Gram-positive bacteria, including Staphylococcus spp., Streptococcus spp. and Listeria monocytogenes.
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Affiliation(s)
- A. Marijke Keestra-Gounder
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Prescilla Emy Nagao
- Laboratory of Molecular Biology and Physiology of Streptococci, Institute of Biology Roberto Alcantara Gomes, Rio de Janeiro State University (UERJ), Rio de Janeiro, Brazil
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11
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Leal VNC, Pontillo A. Canonical Inflammasomes. Methods Mol Biol 2023; 2696:1-27. [PMID: 37578712 DOI: 10.1007/978-1-0716-3350-2_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
The innate immune response represents the first line of host defense, and it is able to detect pathogen- and damage-associated molecular patterns (PAMPs and DAMPs, respectively) through a variety of pattern recognition receptors (PRRs). Among these PRRs, certain cytosolic receptors of the NLRs family (specifically NLRP1, NLRP3, NLRC4, and NAIP) or those containing at least a pyrin domain (PYD) such as pyrin and AIM2, activate the multimeric complex known as inflammasome, and its effector enzyme caspase-1. The caspase-1 induces the proteolytic maturation of the pro-inflammatory cytokines IL-1ß and IL-18, as well as the pore-forming protein gasdermin D (GSDMD). GSDMD is responsible for the release of the two cytokines and the induction of lytic and inflammatory cell death known as pyroptosis. Each inflammasome receptor detects specific stimuli, either directly or indirectly, thereby enhancing the cell's ability to sense infections or homeostatic disturbances. In this chapter, we present the activation mechanism of the so-called "canonical" inflammasomes.
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Affiliation(s)
| | - Alessandra Pontillo
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brasil.
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12
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Brinkschulte R, Fußhöller DM, Hoss F, Rodríguez-Alcázar JF, Lauterbach MA, Kolbe CC, Rauen M, Ince S, Herrmann C, Latz E, Geyer M. ATP-binding and hydrolysis of human NLRP3. Commun Biol 2022; 5:1176. [PMID: 36329210 PMCID: PMC9633759 DOI: 10.1038/s42003-022-04120-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
The innate immune system uses inflammasomal proteins to recognize danger signals and fight invading pathogens. NLRP3, a multidomain protein belonging to the family of STAND ATPases, is characterized by its central nucleotide-binding NACHT domain. The incorporation of ATP is thought to correlate with large conformational changes in NLRP3, leading to an active state of the sensory protein. Here we analyze the intrinsic ATP hydrolysis activity of recombinant NLRP3 by reverse phase HPLC. Wild-type NLRP3 appears in two different conformational states that exhibit an approximately fourteen-fold different hydrolysis activity in accordance with an inactive, autoinhibited state and an open, active state. The impact of canonical residues in the nucleotide binding site as the Walker A and B motifs and sensor 1 and 2 is analyzed by site directed mutagenesis. Cellular experiments show that reduced NLRP3 hydrolysis activity correlates with higher ASC specking after inflammation stimulation. Addition of the kinase NEK7 does not change the hydrolysis activity of NLRP3. Our data provide a comprehensive view on the function of conserved residues in the nucleotide-binding site of NLRP3 and the correlation of ATP hydrolysis with inflammasome activity. Analysis of the inflammasome-forming protein NLRP3 provides insights into the function of conserved residues in the ATP-binding site of NLRP3 and the correlation of ATP hydrolysis with inflammasome activation.
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Affiliation(s)
- Rebecca Brinkschulte
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - David M Fußhöller
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Florian Hoss
- Institute of Innate Immunity, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | | | - Mario A Lauterbach
- Institute of Innate Immunity, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Carl-Christian Kolbe
- Institute of Innate Immunity, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Melanie Rauen
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Semra Ince
- Physical Chemistry I, Ruhr University Bochum, 44780, Bochum, Germany
| | | | - Eicke Latz
- Institute of Innate Immunity, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Matthias Geyer
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany.
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13
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Ohto U. Activation and regulation mechanisms of NOD-like receptors based on structural biology. Front Immunol 2022; 13:953530. [PMID: 36189327 PMCID: PMC9520476 DOI: 10.3389/fimmu.2022.953530] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
Innate immunity is a primary defense system against microbial infections. Innate immune pattern recognition receptors (PRRs) play pivotal roles in detection of invading pathogens. When pathogens, such as bacteria and viruses, invade our bodies, their components are recognized by PRRs as pathogen-associated molecular patterns (PAMPs), activating the innate immune system. Cellular components such as DNA and RNA, acting as damage-associated molecular patterns (DAMPs), also activate innate immunity through PRRs under certain conditions. Activation of PRRs triggers inflammatory responses, interferon-mediated antiviral responses, and the activation of acquired immunity. Research on innate immune receptors is progressing rapidly. A variety of these receptors has been identified, and their regulatory mechanisms have been elucidated. Nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs) constitute a major family of intracellular PRRs and are involved in not only combating pathogen invasion but also maintaining normal homeostasis. Some NLRs are known to form multi-protein complexes called inflammasomes, a process that ultimately leads to the production of inflammatory cytokines and induces pyroptosis through the proteolytic cascade. The aberrant activation of NLRs has been found to be associated with autoimmune diseases. Therefore, NLRs are considered targets for drug discovery, such as for antiviral drugs, immunostimulants, antiallergic drugs, and autoimmune disease drugs. This review summarizes our recent understanding of the activation and regulation mechanisms of NLRs, with a particular focus on their structural biology. These include NOD2, neuronal apoptosis inhibitory protein (NAIP)/NLRC4, NLR family pyrin domain containing 1 (NLRP1), NLRP3, NLRP6, and NLRP9. NLRs are involved in a variety of diseases, and their detailed activation mechanisms based on structural biology can aid in developing therapeutic agents in the future.
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14
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Activation and Pharmacological Regulation of Inflammasomes. Biomolecules 2022; 12:biom12071005. [PMID: 35883561 PMCID: PMC9313256 DOI: 10.3390/biom12071005] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/16/2022] [Accepted: 07/18/2022] [Indexed: 01/27/2023] Open
Abstract
Inflammasomes are intracellular signaling complexes of the innate immune system, which is part of the response to exogenous pathogens or physiological aberration. The multiprotein complexes mainly consist of sensor proteins, adaptors, and pro-caspase-1. The assembly of the inflammasome upon extracellular and intracellular cues drives the activation of caspase-1, which processes pro-inflammatory cytokines IL-1β and IL-18 to maturation and gasdermin-D for pore formation, leading to pyroptosis and cytokine release. Inflammasome signaling functions in numerous infectious or sterile inflammatory diseases, including inherited autoinflammatory diseases, metabolic disorders, cardiovascular diseases, cancers, neurodegenerative disorders, and COVID-19. In this review, we summarized current ideas on the organization and activation of inflammasomes, with details on the molecular mechanisms, regulations, and interventions. The recent developments of pharmacological strategies targeting inflammasomes as disease therapeutics were also covered.
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15
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Angosto-Bazarra D, Molina-López C, Pelegrín P. Physiological and pathophysiological functions of NLRP6: pro- and anti-inflammatory roles. Commun Biol 2022; 5:524. [PMID: 35650327 PMCID: PMC9160023 DOI: 10.1038/s42003-022-03491-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 05/12/2022] [Indexed: 12/26/2022] Open
Abstract
The nucleotide-binding oligomerization and leucine-rich repeat receptor (NLR) protein family consists of important immune sensors that form inflammasomes, a cytosolic multi-protein platform that induces caspase-1 activation and is involved in different inflammatory pathologies. The NLR family pyrin domain containing 6 (NLRP6) is a receptor that can signal by forming inflammasomes, but which can also play an important role without forming inflammasomes. NLRP6 regulates intestinal homeostasis and inflammation, but also is involved in cancer, the nervous system or liver diseases, with both protective and deleterious consequences. In the present article, we review the different roles of NLRP6 in these processes and offer new insights into NLRP6 activation. This review discusses emerging roles for the NLR family pyrin domain containing 6 receptor (NLRP6) in intestinal homeostasis, inflammation, cancer, the nervous system and liver disease.
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Affiliation(s)
- Diego Angosto-Bazarra
- Línea de Inflamación Molecular, Instituto Murciano de Investigación Biosanitaria IMIB-Arrixaca, Hospital Clínico Universitario Virgen de la Arrixaca, 30120, Murcia, Spain.
| | - Cristina Molina-López
- Línea de Inflamación Molecular, Instituto Murciano de Investigación Biosanitaria IMIB-Arrixaca, Hospital Clínico Universitario Virgen de la Arrixaca, 30120, Murcia, Spain
| | - Pablo Pelegrín
- Línea de Inflamación Molecular, Instituto Murciano de Investigación Biosanitaria IMIB-Arrixaca, Hospital Clínico Universitario Virgen de la Arrixaca, 30120, Murcia, Spain. .,Department of Biochemistry and Molecular Biology B and Immunology, Faculty of Medicine, University of Murcia, 30120, Murcia, Spain.
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16
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Hochheiser IV, Behrmann H, Hagelueken G, Rodríguez-Alcázar JF, Kopp A, Latz E, Behrmann E, Geyer M. Directionality of PYD filament growth determined by the transition of NLRP3 nucleation seeds to ASC elongation. SCIENCE ADVANCES 2022; 8:eabn7583. [PMID: 35559676 PMCID: PMC9106292 DOI: 10.1126/sciadv.abn7583] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Inflammasomes sense intrinsic and extrinsic danger signals to trigger inflammatory responses and pyroptotic cell death. Homotypic pyrin domain (PYD) interactions of inflammasome forming nucleotide-binding oligomerization domain (NOD)-like receptors with the adaptor protein ASC (apoptosis-associated speck-like protein containing a CARD) mediate oligomerization into filamentous assemblies. We describe the cryo-electron microscopy (cryo-EM) structure of the human NLRP3PYD filament and identify a pattern of highly polar interface residues that form the homomeric interactions leading to characteristic filament ends designated as A- and B-ends. Coupling a titration polymerization assay to cryo-EM, we demonstrate that ASC adaptor protein elongation on NLRP3PYD nucleation seeds is unidirectional, associating exclusively to the B-end of the filament. Notably, NLRP3 and ASC PYD filaments exhibit the same symmetry in rotation and axial rise per subunit, allowing a continuous transition between NLRP3 and ASC. Integrating the directionality of filament growth, we present a molecular model of the ASC speck consisting of active NLRP3, ASC, and Caspase-1 proteins.
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Affiliation(s)
- Inga V. Hochheiser
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Heide Behrmann
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Gregor Hagelueken
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | | | - Anja Kopp
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, 12 Parkville, VIC 3052, Australia
| | - Eicke Latz
- Institute of Innate Immunity, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Elmar Behrmann
- Institute of Biochemistry, University of Cologne, Zülpicher Straße 47, 50674 Cologne, Germany
| | - Matthias Geyer
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
- Corresponding author.
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17
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Kamitsukasa Y, Nakano K, Murakami K, Hirata K, Yamamoto M, Shimizu T, Ohto U. The structure of NLRP9 reveals a unique C-terminal region with putative regulatory function. FEBS Lett 2022; 596:876-885. [PMID: 35090055 DOI: 10.1002/1873-3468.14302] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/17/2022] [Accepted: 01/24/2022] [Indexed: 11/07/2022]
Abstract
Nucleotide-binding and oligomerization domain-like receptors (NLRs) can form inflammasomes that activate caspase-1 and pro-interleukin-1β and induce pyroptosis. NLR family pyrin domain-containing 9 (NLRP9) forms an inflammasome and activates innate immune responses during virus infection, but little is known about this process. Here, we report the crystal and cryo-electron microscopy structures of NLRP9 in an ADP-bound state, revealing inactive and closed conformations of NLRP9 and its similarities to other structurally characterised NLRs. Moreover, we found a C-terminal region interacting with the concave surface of the leucine-rich repeat domain of NLRP9. This region is unique among NLRs and might be involved in the specific function of NLRP9. These data provide the structural basis for understanding the mechanism of NLRP9 regulation and activation.
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Affiliation(s)
- Yukie Kamitsukasa
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Kenji Nakano
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Karin Murakami
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Kunio Hirata
- RIKEN Spring-8 Center, Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan
| | - Masaki Yamamoto
- RIKEN Spring-8 Center, Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan
| | - Toshiyuki Shimizu
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Umeharu Ohto
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
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18
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Naseer N, Egan MS, Reyes Ruiz VM, Scott WP, Hunter EN, Demissie T, Rauch I, Brodsky IE, Shin S. Human NAIP/NLRC4 and NLRP3 inflammasomes detect Salmonella type III secretion system activities to restrict intracellular bacterial replication. PLoS Pathog 2022; 18:e1009718. [PMID: 35073381 PMCID: PMC8812861 DOI: 10.1371/journal.ppat.1009718] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 02/03/2022] [Accepted: 12/27/2021] [Indexed: 01/16/2023] Open
Abstract
Salmonella enterica serovar Typhimurium is a Gram-negative pathogen that uses two distinct type III secretion systems (T3SSs), termed Salmonella pathogenicity island (SPI)-1 and SPI-2, to deliver virulence factors into the host cell. The SPI-1 T3SS enables Salmonella to invade host cells, while the SPI-2 T3SS facilitates Salmonella's intracellular survival. In mice, a family of cytosolic immune sensors, including NAIP1, NAIP2, and NAIP5/6, recognizes the SPI-1 T3SS needle, inner rod, and flagellin proteins, respectively. Ligand recognition triggers assembly of the NAIP/NLRC4 inflammasome, which mediates caspase-1 activation, IL-1 family cytokine secretion, and pyroptosis of infected cells. In contrast to mice, humans encode a single NAIP that broadly recognizes all three ligands. The role of NAIP/NLRC4 or other inflammasomes during Salmonella infection of human macrophages is unclear. We find that although the NAIP/NLRC4 inflammasome is essential for detecting T3SS ligands in human macrophages, it is partially required for responses to infection, as Salmonella also activated the NLRP3 and CASP4/5 inflammasomes. Importantly, we demonstrate that combinatorial NAIP/NLRC4 and NLRP3 inflammasome activation restricts Salmonella replication in human macrophages. In contrast to SPI-1, the SPI-2 T3SS inner rod is not sensed by human or murine NAIPs, which is thought to allow Salmonella to evade host recognition and replicate intracellularly. Intriguingly, we find that human NAIP detects the SPI-2 T3SS needle protein. Critically, in the absence of both flagellin and the SPI-1 T3SS, the NAIP/NLRC4 inflammasome still controlled intracellular Salmonella burden. These findings reveal that recognition of Salmonella SPI-1 and SPI-2 T3SSs and engagement of both the NAIP/NLRC4 and NLRP3 inflammasomes control Salmonella infection in human macrophages.
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Affiliation(s)
- Nawar Naseer
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Marisa S. Egan
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Valeria M. Reyes Ruiz
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - William P. Scott
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon
| | - Emma N. Hunter
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Tabitha Demissie
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Isabella Rauch
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon
| | - Igor E. Brodsky
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania
| | - Sunny Shin
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
- * E-mail:
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19
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Shen C, Li R, Negro R, Cheng J, Vora SM, Fu TM, Wang A, He K, Andreeva L, Gao P, Tian Z, Flavell RA, Zhu S, Wu H. Phase separation drives RNA virus-induced activation of the NLRP6 inflammasome. Cell 2021; 184:5759-5774.e20. [PMID: 34678144 DOI: 10.1016/j.cell.2021.09.032] [Citation(s) in RCA: 106] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 07/06/2021] [Accepted: 09/24/2021] [Indexed: 11/27/2022]
Abstract
NLRP6 is important in host defense by inducing functional outcomes including inflammasome activation and interferon production. Here, we show that NLRP6 undergoes liquid-liquid phase separation (LLPS) upon interaction with double-stranded RNA (dsRNA) in vitro and in cells, and an intrinsically disordered poly-lysine sequence (K350-354) of NLRP6 is important for multivalent interactions, phase separation, and inflammasome activation. Nlrp6-deficient or Nlrp6K350-354A mutant mice show reduced inflammasome activation upon mouse hepatitis virus or rotavirus infection, and in steady state stimulated by intestinal microbiota, implicating NLRP6 LLPS in anti-microbial immunity. Recruitment of ASC via helical assembly solidifies NLRP6 condensates, and ASC further recruits and activates caspase-1. Lipoteichoic acid, a known NLRP6 ligand, also promotes NLRP6 LLPS, and DHX15, a helicase in NLRP6-induced interferon signaling, co-forms condensates with NLRP6 and dsRNA. Thus, LLPS of NLRP6 is a common response to ligand stimulation, which serves to direct NLRP6 to distinct functional outcomes depending on the cellular context.
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Affiliation(s)
- Chen Shen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Runzhi Li
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China; Institute of Immunology, University of Science and Technology of China, Hefei, China
| | - Roberto Negro
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA; National Institute of Gastroenterology, "S. de Bellis" Research Hospital, Castellana Grotte, Bari 70013, Italy
| | - Jiewei Cheng
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China; Institute of Immunology, University of Science and Technology of China, Hefei, China
| | - Setu M Vora
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Tian-Min Fu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA; The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Anmin Wang
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China; Institute of Immunology, University of Science and Technology of China, Hefei, China
| | - Kaixin He
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China; Institute of Immunology, University of Science and Technology of China, Hefei, China
| | - Liudmila Andreeva
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Pu Gao
- CAS Key Laboratory of Infection and Immunity, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhigang Tian
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China; Institute of Immunology, University of Science and Technology of China, Hefei, China
| | - Richard A Flavell
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA; Howard Hughes Medical Institute, New Haven, CT, USA
| | - Shu Zhu
- Hefei National Laboratory for Physical Sciences at Microscale, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China; Institute of Immunology, University of Science and Technology of China, Hefei, China.
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
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20
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Xia S, Chen Z, Shen C, Fu TM. Higher-order assemblies in immune signaling: supramolecular complexes and phase separation. Protein Cell 2021; 12:680-694. [PMID: 33835418 PMCID: PMC8403095 DOI: 10.1007/s13238-021-00839-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 03/01/2021] [Indexed: 12/31/2022] Open
Abstract
Signaling pathways in innate and adaptive immunity play vital roles in pathogen recognition and the functions of immune cells. Higher-order assemblies have recently emerged as a central principle that governs immune signaling and, by extension, cellular communication in general. There are mainly two types of higher-order assemblies: 1) ordered, solid-like large supramolecular complexes formed by stable and rigid protein-protein interactions, and 2) liquid-like phase-separated condensates formed by weaker and more dynamic intermolecular interactions. This review covers key examples of both types of higher-order assemblies in major immune pathways. By placing emphasis on the molecular structures of the examples provided, we discuss how their structural organization enables elegant mechanisms of signaling regulation.
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MESH Headings
- Adaptive Immunity
- Animals
- DEAD Box Protein 58/genetics
- DEAD Box Protein 58/immunology
- DEAD Box Protein 58/metabolism
- DEAD-box RNA Helicases/genetics
- DEAD-box RNA Helicases/immunology
- DEAD-box RNA Helicases/metabolism
- Gene Expression Regulation
- Humans
- Immunity, Innate
- Inflammasomes/genetics
- Inflammasomes/immunology
- Inflammasomes/ultrastructure
- Models, Molecular
- Multiprotein Complexes/genetics
- Multiprotein Complexes/immunology
- Multiprotein Complexes/metabolism
- Protein Conformation
- Protein Interaction Mapping
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/metabolism
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/metabolism
- Receptors, Immunologic/genetics
- Receptors, Immunologic/immunology
- Receptors, Immunologic/metabolism
- Receptors, Tumor Necrosis Factor, Type I/genetics
- Receptors, Tumor Necrosis Factor, Type I/immunology
- Receptors, Tumor Necrosis Factor, Type I/metabolism
- Signal Transduction/immunology
- Toll-Like Receptors/genetics
- Toll-Like Receptors/immunology
- Toll-Like Receptors/metabolism
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Affiliation(s)
- Shiyu Xia
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Zhenhang Chen
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH, 43210, USA
| | - Chen Shen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Tian-Min Fu
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA.
- The Ohio State University Comprehensive Cancer Center, Columbus, OH, 43210, USA.
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21
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Li Y, Lv J, Shi W, Feng J, Liu M, Gan S, Wu H, Fan W, Shi M. Inflammasome Signaling: A Novel Paradigm of Hub Platform in Innate Immunity for Cancer Immunology and Immunotherapy. Front Immunol 2021; 12:710110. [PMID: 34421915 PMCID: PMC8374049 DOI: 10.3389/fimmu.2021.710110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 07/21/2021] [Indexed: 12/31/2022] Open
Abstract
Inflammasomes are fundamental innate immune mechanisms that promote inflammation and induce an inflammatory form of programmed cell death, pyroptosis. Pyroptotic inflammasome has been reported to be closely associated with tumorigenesis and prognosis of multiple cancers. Emerging studies show that the inflammasome assembly into a higher-order supramolecular complex has been utilized to evaluate the status of the innate immune response. The inflammasomes are now regarded as cellular signaling hubs of the innate immunity that drive the production of inflammatory cytokines and consequent recruitment of immune cells to the tumor sites. Herein, we provided an overview of molecular characteristics and biological properties of canonical and non-canonical inflammasome signaling in cancer immunology and immunotherapy. We also focus on the mechanism of regulating pyroptotic inflammasome in tumor cells, as well as the potential roles of inflammasome-mediated pyroptotic cell death in cancers, to explore the potential diagnostic and therapeutic markers contributing to the prevention and treatment of cancers.
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Affiliation(s)
- Ying Li
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China.,International Research Center for Regenerative Medicine, BOAO International Hospital, Qionghai, China
| | - Jiao Lv
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Weikai Shi
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Jia Feng
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Mingxi Liu
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Shenao Gan
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Hongjin Wu
- International Research Center for Regenerative Medicine, BOAO International Hospital, Qionghai, China
| | - Weiwei Fan
- Department of Infectious and Medicine, Heilongjiang Provincial Hospital, Harbin, China
| | - Ming Shi
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
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22
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Duxbury Z, Wu CH, Ding P. A Comparative Overview of the Intracellular Guardians of Plants and Animals: NLRs in Innate Immunity and Beyond. ANNUAL REVIEW OF PLANT BIOLOGY 2021; 72:155-184. [PMID: 33689400 DOI: 10.1146/annurev-arplant-080620-104948] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nucleotide-binding domain leucine-rich repeat receptors (NLRs) play important roles in the innate immune systems of both plants and animals. Recent breakthroughs in NLR biochemistry and biophysics have revolutionized our understanding of how NLR proteins function in plant immunity. In this review, we summarize the latest findings in plant NLR biology and draw direct comparisons to NLRs of animals. We discuss different mechanisms by which NLRs recognize their ligands in plants and animals. The discovery of plant NLR resistosomes that assemble in a comparable way to animal inflammasomes reinforces the striking similarities between the formation of plant and animal NLR complexes. Furthermore, we discuss the mechanisms by which plant NLRs mediate immune responses and draw comparisons to similar mechanisms identified in animals. Finally, we summarize the current knowledge of the complex genetic architecture formed by NLRs in plants and animals and the roles of NLRs beyond pathogen detection.
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Affiliation(s)
- Zane Duxbury
- Jealott's Hill International Research Centre, Syngenta, Bracknell RG42 6EY, United Kingdom;
| | - Chih-Hang Wu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan;
| | - Pingtao Ding
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, United Kingdom
- Current affiliation: Institute of Biology Leiden, Leiden University, Leiden 2333 BE, The Netherlands;
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23
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Structures and functions of the inflammasome engine. J Allergy Clin Immunol 2021; 147:2021-2029. [PMID: 34092352 DOI: 10.1016/j.jaci.2021.04.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/18/2021] [Accepted: 04/20/2021] [Indexed: 01/07/2023]
Abstract
Inflammasomes are molecular machines that carry out inflammatory responses on challenges by pathogens and endogenous dangers. Dysregulation of inflammasome assembly and regulation is associated with numerous human diseases from autoimmunity to cancer. In recent years, significant advances have been made in understanding the mechanism of inflammasome signaling using structural approaches. Here, we review inflammasomes formed by the NLRP1, NLRP3, and NLRC4 sensors, which are well characterized structurally, and discuss the structural and functional diversity among them.
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24
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Gong Q, Robinson K, Xu C, Huynh PT, Chong KHC, Tan EYJ, Zhang J, Boo ZZ, Teo DET, Lay K, Zhang Y, Lim JSY, Goh WI, Wright G, Zhong FL, Reversade B, Wu B. Structural basis for distinct inflammasome complex assembly by human NLRP1 and CARD8. Nat Commun 2021; 12:188. [PMID: 33420028 PMCID: PMC7794362 DOI: 10.1038/s41467-020-20319-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 11/25/2020] [Indexed: 02/07/2023] Open
Abstract
Nod-like receptor (NLR) proteins activate pyroptotic cell death and IL-1 driven inflammation by assembling and activating the inflammasome complex. Closely related sensor proteins NLRP1 and CARD8 undergo unique auto-proteolysis-dependent activation and are implicated in auto-inflammatory diseases; however, their mechanisms of activation are not understood. Here we report the structural basis of how the activating domains (FIINDUPA-CARD) of NLRP1 and CARD8 self-oligomerize to assemble distinct inflammasome complexes. Recombinant FIINDUPA-CARD of NLRP1 forms a two-layered filament, with an inner core of oligomerized CARD surrounded by an outer ring of FIINDUPA. Biochemically, self-assembled NLRP1-CARD filaments are sufficient to drive ASC speck formation in cultured human cells-a process that is greatly enhanced by NLRP1-FIINDUPA which forms oligomers in vitro. The cryo-EM structures of NLRP1-CARD and CARD8-CARD filaments, solved here at 3.7 Å, uncover unique structural features that enable NLRP1 and CARD8 to discriminate between ASC and pro-caspase-1. In summary, our findings provide structural insight into the mechanisms of activation for human NLRP1 and CARD8 and reveal how highly specific signaling can be achieved by heterotypic CARD interactions within the inflammasome complexes.
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Affiliation(s)
- Qin Gong
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, 636921, Singapore
| | - Kim Robinson
- Skin Research Institute (SRIS), Agency of Science Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, 138648, Singapore, Singapore
| | - Chenrui Xu
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, 636921, Singapore
| | - Phuong Thao Huynh
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, 636921, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technology University, 11 Mandalay Road, 308232, Singapore, Singapore
| | - Kelvin Han Chung Chong
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, 636921, Singapore
| | - Eddie Yong Jun Tan
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, 636921, Singapore
| | - Jiawen Zhang
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, 636921, Singapore
| | - Zhao Zhi Boo
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, 636921, Singapore
| | - Daniel Eng Thiam Teo
- Institute of Molecular and Cell Biology, Agency of Science Technology and Research (A*STAR), 61 Biopolis Dr, 138673, Singapore, Singapore
| | - Kenneth Lay
- Institute of Molecular and Cell Biology, Agency of Science Technology and Research (A*STAR), 61 Biopolis Dr, 138673, Singapore, Singapore
| | - Yaming Zhang
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, 636921, Singapore
| | - John Soon Yew Lim
- Skin Research Institute (SRIS), Agency of Science Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, 138648, Singapore, Singapore
| | - Wah Ing Goh
- Skin Research Institute (SRIS), Agency of Science Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, 138648, Singapore, Singapore
| | - Graham Wright
- Institute of Molecular and Cell Biology, Agency of Science Technology and Research (A*STAR), 61 Biopolis Dr, 138673, Singapore, Singapore
| | - Franklin L Zhong
- Skin Research Institute (SRIS), Agency of Science Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, 138648, Singapore, Singapore.
- Lee Kong Chian School of Medicine, Nanyang Technology University, 11 Mandalay Road, 308232, Singapore, Singapore.
- Institute of Molecular and Cell Biology, Agency of Science Technology and Research (A*STAR), 61 Biopolis Dr, 138673, Singapore, Singapore.
| | - Bruno Reversade
- Institute of Molecular and Cell Biology, Agency of Science Technology and Research (A*STAR), 61 Biopolis Dr, 138673, Singapore, Singapore.
- Genome Institute of Singapore, Agency of Science Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, 138648, Singapore, Singapore.
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Dr, 117597, Singapore, Singapore.
- The Medical Genetics Department, School of Medicine (KUSoM), Koç University, 34010, Istanbul, Turkey.
| | - Bin Wu
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore.
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, 636921, Singapore.
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25
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Robert Hollingsworth L, David L, Li Y, Griswold AR, Ruan J, Sharif H, Fontana P, Orth-He EL, Fu TM, Bachovchin DA, Wu H. Mechanism of filament formation in UPA-promoted CARD8 and NLRP1 inflammasomes. Nat Commun 2021; 12:189. [PMID: 33420033 PMCID: PMC7794386 DOI: 10.1038/s41467-020-20320-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 11/26/2020] [Indexed: 01/29/2023] Open
Abstract
NLRP1 and CARD8 are related cytosolic sensors that upon activation form supramolecular signalling complexes known as canonical inflammasomes, resulting in caspase-1 activation, cytokine maturation and/or pyroptotic cell death. NLRP1 and CARD8 use their C-terminal (CT) fragments containing a caspase recruitment domain (CARD) and the UPA (conserved in UNC5, PIDD, and ankyrins) subdomain for self-oligomerization, which in turn form the platform to recruit the inflammasome adaptor ASC (apoptosis-associated speck-like protein containing a CARD) or caspase-1, respectively. Here, we report cryo-EM structures of NLRP1-CT and CARD8-CT assemblies, in which the respective CARDs form central helical filaments that are promoted by oligomerized, but flexibly linked, UPAs surrounding the filaments. Through biochemical and cellular approaches, we demonstrate that the UPA itself reduces the threshold needed for NLRP1-CT and CARD8-CT filament formation and signalling. Structural analyses provide insights on the mode of ASC recruitment by NLRP1-CT and the contrasting direct recruitment of caspase-1 by CARD8-CT. We also discover that subunits in the central NLRP1CARD filament dimerize with additional exterior CARDs, which roughly doubles its thickness and is unique among all known CARD filaments. Finally, we engineer and determine the structure of an ASCCARD-caspase-1CARD octamer, which suggests that ASC uses opposing surfaces for NLRP1, versus caspase-1, recruitment. Together these structures capture the architecture and specificity of the active NLRP1 and CARD8 inflammasomes in addition to key heteromeric CARD-CARD interactions governing inflammasome signalling.
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Affiliation(s)
- L Robert Hollingsworth
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115, USA
- Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA, 02115, USA
| | - Liron David
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Yang Li
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Andrew R Griswold
- Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY, USA
- Pharmacology Program, Weill Cornell Graduate School of Medical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Jianbin Ruan
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Immunology, University of Connecticut Health Center, Farmington, CT, USA
| | - Humayun Sharif
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Pietro Fontana
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Elizabeth L Orth-He
- Tri-Institutional PhD Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Tian-Min Fu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Biological Chemistry and Pharmacology, Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Daniel A Bachovchin
- Pharmacology Program, Weill Cornell Graduate School of Medical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
- Tri-Institutional PhD Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115, USA.
- Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA, 02115, USA.
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26
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Song W, Forderer A, Yu D, Chai J. Structural biology of plant defence. THE NEW PHYTOLOGIST 2021; 229:692-711. [PMID: 32880948 DOI: 10.1111/nph.16906] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 07/14/2020] [Indexed: 06/11/2023]
Abstract
Plants employ the innate immune system to discriminate between self and invaders through two types of immune receptors, one on the plasma membrane and the other in the intracellular space. The immune receptors on the plasma membrane are pattern recognition receptors (PRRs) that can perceive pathogen-associated molecular patterns (PAMPs) or host-derived damage-associated molecular patterns (DAMPs) leading to pattern-triggered immunity (PTI). Particular pathogens are capable of overcoming PTI by secreting specific effectors into plant cells to perturb different components of PTI signalling through various mechanisms. Most of the immune receptors from the intracellular space are the nucleotide-binding leucine-rich repeat receptors (NLRs), which specifically recognize pathogen-secreted effectors to mediate effector-triggered immunity (ETI). In this review, we will summarize recent progress in structural studies of PRRs, NLRs, and effectors, and discuss how these studies shed light on ligand recognition and activation mechanisms of the two types of immune receptors and the diversified mechanisms used by effectors to manipulate plant immune signalling.
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Affiliation(s)
- Wen Song
- Max-Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
- Institute of Biochemistry, University of Cologne, Cologne, 50923, Germany
| | - Alexander Forderer
- Max-Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
- Institute of Biochemistry, University of Cologne, Cologne, 50923, Germany
| | - Dongli Yu
- Max-Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
- Institute of Biochemistry, University of Cologne, Cologne, 50923, Germany
| | - Jijie Chai
- Max-Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
- Institute of Biochemistry, University of Cologne, Cologne, 50923, Germany
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27
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Sandall CF, Ziehr BK, MacDonald JA. ATP-Binding and Hydrolysis in Inflammasome Activation. Molecules 2020; 25:molecules25194572. [PMID: 33036374 PMCID: PMC7583971 DOI: 10.3390/molecules25194572] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 02/06/2023] Open
Abstract
The prototypical model for NOD-like receptor (NLR) inflammasome assembly includes nucleotide-dependent activation of the NLR downstream of pathogen- or danger-associated molecular pattern (PAMP or DAMP) recognition, followed by nucleation of hetero-oligomeric platforms that lie upstream of inflammatory responses associated with innate immunity. As members of the STAND ATPases, the NLRs are generally thought to share a similar model of ATP-dependent activation and effect. However, recent observations have challenged this paradigm to reveal novel and complex biochemical processes to discern NLRs from other STAND proteins. In this review, we highlight past findings that identify the regulatory importance of conserved ATP-binding and hydrolysis motifs within the nucleotide-binding NACHT domain of NLRs and explore recent breakthroughs that generate connections between NLR protein structure and function. Indeed, newly deposited NLR structures for NLRC4 and NLRP3 have provided unique perspectives on the ATP-dependency of inflammasome activation. Novel molecular dynamic simulations of NLRP3 examined the active site of ADP- and ATP-bound models. The findings support distinctions in nucleotide-binding domain topology with occupancy of ATP or ADP that are in turn disseminated on to the global protein structure. Ultimately, studies continue to reveal how the ATP-binding and hydrolysis properties of NACHT domains in different NLRs integrate with signaling modules and binding partners to control innate immune responses at the molecular level.
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28
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Rahman T, Nagar A, Duffy EB, Okuda K, Silverman N, Harton JA. NLRP3 Sensing of Diverse Inflammatory Stimuli Requires Distinct Structural Features. Front Immunol 2020; 11:1828. [PMID: 32983094 PMCID: PMC7479093 DOI: 10.3389/fimmu.2020.01828] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/08/2020] [Indexed: 12/30/2022] Open
Abstract
The NLRP3 inflammasome is central to host defense and implicated in various inflammatory diseases and conditions. While the favored paradigm of NLRP3 inflammasome activation stipulates a unifying signal intermediate that de-represses NLRP3, this view has not been tested. Further, structures within NLRP3 required for inflammasome activation are poorly defined. Here we demonstrate that while the NLRP3 LRRs are not auto-repressive and are not required for inflammasome activation by all agonists, distinct sequences within the NLRP3 LRRs positively and negatively modulate inflammasome activation by specific ligands. In addition, elements within the HD1/HD2 “hinge” of NLRP3 and the nucleotide-binding domain have contrasting functions depending upon the specific agonists. Further, while NLRP3 1–432 is minimally sufficient for inflammasome activation by all agonists tested, the pyrin, and linker domains (1–134) function cooperatively and are sufficient for inflammasome activation by certain agonists. Conserved cysteines 8 and 108 appear important for inflammasome activation by sterile, but not infectious insults. Our results define common and agonist-specific regions of NLRP3 that likely mediate ligand-specific responses, discount the hypothesis that NLRP3 inflammasome activation has a unified mechanism, and implicate NLRP3 as an integrator of agonist-specific, inflammasome activating signals.
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Affiliation(s)
- Tabassum Rahman
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Abhinit Nagar
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Ellen B Duffy
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Kendi Okuda
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States
| | - Neal Silverman
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States
| | - Jonathan A Harton
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
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29
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de Alba E. The mysterious role of the NLRP9 pyrin domain in inflammasome assembly. FEBS Lett 2020; 594:2380-2382. [PMID: 32735703 DOI: 10.1002/1873-3468.13889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Eva de Alba
- Department of Bioengineering. School of Engineering, University of California, Merced, CA, USA
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30
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Xiong Y, Han Z, Chai J. Resistosome and inflammasome: platforms mediating innate immunity. CURRENT OPINION IN PLANT BIOLOGY 2020; 56:47-55. [PMID: 32554225 DOI: 10.1016/j.pbi.2020.03.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 03/12/2020] [Accepted: 03/23/2020] [Indexed: 06/11/2023]
Abstract
The nucleotide-binding domain (NBD) and leucine-rich repeat (LRR) containing (NLR) proteins are intracellular immune receptors that sense pathogens or stress-associated signals in animals and plants. Direct or indirect binding of these stimuli to NLRs results in formation of higher-order large protein complexes termed inflammasomes in animals and resistosomes in plants to mediate immune signaling. Here we focus on plant NLRs and discuss the activation mechanism of the ZAR1 resistosome from Arabidopsis thaliana. We also outline the analogies and differences between the ZAR1 resistosome and the NLR inflammasomes, and discuss how the structural and biochemical information available on these two large types of protein complexes sheds light on signaling mechanisms of other plant NLRs.
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Affiliation(s)
- Yehui Xiong
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Zhifu Han
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jijie Chai
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, 100084 Beijing, China; Max Planck Institute for Plant Breeding Research, Cologne, Germany; Institute of Biochemistry, University of Cologne, Zuelpicher Strasse 47, 50674 Cologne, Germany.
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31
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Induced proximity of a TIR signaling domain on a plant-mammalian NLR chimera activates defense in plants. Proc Natl Acad Sci U S A 2020; 117:18832-18839. [PMID: 32709746 PMCID: PMC7414095 DOI: 10.1073/pnas.2001185117] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Animal NLRs form wheel-like structures called inflammasomes upon perception of pathogen-associated molecules. The induced proximity of the signaling domains at the center of the wheel is hypothesized to recruit caspases for the first step of immune signal transduction. We expressed a plant-animal NLR fusion to demonstrate that induced proximity of TIR signaling domains from plant NLRs is sufficient to activate plant immune signaling. This demonstrates that a signaling-competent inflammasome can be formed from known, minimal components. The intrinsic NADase activity of plant TIRs is necessary for immune signaling, but fusions to a bacterial or a mammalian TIR domain with NADase activity, which also lead to accumulation of NAD+ hydrolysis products (e.g. cyclic ADP-ribose), were unable to activate immune signaling. Plant and animal intracellular nucleotide-binding, leucine-rich repeat (NLR) immune receptors detect pathogen-derived molecules and activate defense. Plant NLRs can be divided into several classes based upon their N-terminal signaling domains, including TIR (Toll-like, Interleukin-1 receptor, Resistance protein)- and CC (coiled-coil)-NLRs. Upon ligand detection, mammalian NAIP and NLRC4 NLRs oligomerize, forming an inflammasome that induces proximity of its N-terminal signaling domains. Recently, a plant CC-NLR was revealed to form an inflammasome-like hetero-oligomer. To further investigate plant NLR signaling mechanisms, we fused the N-terminal TIR domain of several plant NLRs to the N terminus of NLRC4. Inflammasome-dependent induced proximity of the TIR domain in planta initiated defense signaling. Thus, induced proximity of a plant TIR domain imposed by oligomerization of a mammalian inflammasome is sufficient to activate authentic plant defense. Ligand detection and inflammasome formation is maintained when the known components of the NLRC4 inflammasome is transferred across kingdoms, indicating that NLRC4 complex can robustly function without any additional mammalian proteins. Additionally, we found NADase activity of a plant TIR domain is necessary for plant defense activation, but NADase activity of a mammalian or a bacterial TIR is not sufficient to activate defense in plants.
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32
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Marleaux M, Anand K, Latz E, Geyer M. Crystal structure of the human NLRP9 pyrin domain suggests a distinct mode of inflammasome assembly. FEBS Lett 2020; 594:2383-2395. [PMID: 32542665 DOI: 10.1002/1873-3468.13865] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/17/2020] [Accepted: 06/01/2020] [Indexed: 12/18/2022]
Abstract
Inflammasomes are cytosolic multimeric signaling complexes of the innate immune system that induce activation of caspases. The NOD-like receptor NLRP9 recruits the adaptor protein ASC to form an ASC-dependent inflammasome to limit rotaviral replication in intestinal epithelial cells, but only little is known about the molecular mechanisms regulating and driving its assembly. Here, we present the crystal structure of the human NLRP9 pyrin domain (PYD). We show that NLRP9PYD is not able to self-polymerize nor to nucleate ASC specks in HEK293T cells. A comparison with filament-forming PYDs revealed that NLRP9PYD adopts a conformation compatible with filament formation, but several charge inversions of interfacing residues might cause repulsive effects that prohibit self-oligomerization. These results propose that inflammasome assembly of NLRP9 might differ largely from what we know of other inflammasomes.
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Affiliation(s)
- Michael Marleaux
- Institute of Structural Biology, University of Bonn, Bonn, Germany
| | - Kanchan Anand
- Institute of Structural Biology, University of Bonn, Bonn, Germany
| | - Eicke Latz
- Institute of Innate Immunity, University of Bonn, Bonn, Germany
| | - Matthias Geyer
- Institute of Structural Biology, University of Bonn, Bonn, Germany
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Andrade WA, Zamboni DS. NLRC4 biology in immunity and inflammation. J Leukoc Biol 2020; 108:1117-1127. [PMID: 32531834 DOI: 10.1002/jlb.3mr0420-573r] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/29/2020] [Accepted: 05/05/2020] [Indexed: 12/14/2022] Open
Abstract
Inflammasomes are cytosolic multiprotein complexes that sense microbial infections or host cell damage, triggering cytokine production and a proinflammatory form of cell death, called pyroptosis. Whereas pyroptosis and cytokine production may often promote host resistance to infections, uncontrolled inflammasome activation leads to autoinflammatory diseases in humans. Among the multiple inflammasomes described, the neuronal apoptosis inhibitory protein/nucleotide-binding domain leucine-rich repeat-containing protein family caspase activation and recruitment domain-containing protein 4 (NLRC4) inflammasome emerged as a critical component for the restriction of bacterial infections. Accordingly, our understanding of this inflammasome advanced remarkably over the last 10 yr, expanding our knowledge about ligand-receptor interaction; cryo-EM structure; and downstream effectors and substrates, such as gasdermin-D, caspase-1, caspase-8, and caspase-7. In this review, we discuss recent advances on the biology of the NLRC4 inflammasome, in terms of structure and activation mechanisms, importance in bacterial and nonbacterial diseases, and the identification of NLRC4 gain-of-function mutations leading to NLRC4-associated autoinflammatory diseases in humans.
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Affiliation(s)
- Warrison A Andrade
- Department of Cell Biology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - Dario S Zamboni
- Department of Cell Biology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
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Bauer R, Rauch I. The NAIP/NLRC4 inflammasome in infection and pathology. Mol Aspects Med 2020; 76:100863. [PMID: 32499055 DOI: 10.1016/j.mam.2020.100863] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/30/2020] [Indexed: 12/16/2022]
Abstract
In this review we give an overview of the NAIP/NLRC4 activation mechanism as well as the described roles of this inflammasome, with a focus on in vivo infection and pathology. After ligand recognition by NAIP sensor proteins the NAIP/NLRC4 inflammasome forms through oligomerization with the NLRC4 adaptor to activate Caspase-1. The activating ligands are intracellular bacterial flagellin or type-3 secretion system components, delivered by pathogens. In vivo experiments indicate a role in macrophages during lung, spleen and liver infection and systemic sepsis like conditions, as well as in intestinal epithelial cells. Upon NAIP/NLRC4 activation in the intestine, epithelial cell extrusion is triggered in addition to the canonical inflammasome outcomes of cytokine cleavage and pyroptosis. Human patients with auto-activating mutations in NLRC4 present with an autoinflammatory syndrome including enterocolitis. Although one of the better understood inflammasomes in terms of mechanism, tissue specific functions of NAIP/NLRC4 are only beginning to be understood.
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Affiliation(s)
- Renate Bauer
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA; Department of Biosciences, University of Salzburg, A-5020, Salzburg, Austria
| | - Isabella Rauch
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA.
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35
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Ghimire L, Paudel S, Jin L, Jeyaseelan S. The NLRP6 inflammasome in health and disease. Mucosal Immunol 2020; 13:388-398. [PMID: 31988468 PMCID: PMC7493825 DOI: 10.1038/s41385-020-0256-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 01/05/2020] [Accepted: 01/08/2020] [Indexed: 02/07/2023]
Abstract
NACHT, LRR (leucine-rich repeat), and PYD (pyrin domain) domain-containing 6 (Nlrp6) is a member of the NLR (nucleotide-oligomerization domain-like receptor) family that patrols the cytosolic compartment of cells to detect pathogen- and damage-associated molecular patterns. Because Nlrp6 is a recently discovered inflammasome, details of its signaling mechanism, structural assembly, and roles in host defense have yet to be determined. To date, Nlrp6 has been proposed to perform a multitude of functions ranging from control of microbiota, maintenance of epithelial integrity, and regulation of metabolic diseases to modulation of host defense during microbial infections, cancer protection, and regulation of neuroinflammation. While recent studies have questioned some of the proposed functions of Nlrp6, Nlrp6 has been shown to form an inflammasome complex and cleaves interleukin-1β (IL-1β) and IL-18 during microbial infection, indicating that it is a bonafide inflammasome. In this review, we summarize the recent advancements in knowledge of the signaling mechanisms and structure of the Nlrp6 inflammasome and discuss the relevance of NLRP6 to human disease.
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Affiliation(s)
- Laxman Ghimire
- Department of Pathobiological Sciences, School of Veterinary Medicine, Center for Lung Biology and Disease, Louisiana State University (LSU), Baton Rouge, LA, 70803, USA
| | - Sagar Paudel
- Department of Pathobiological Sciences, School of Veterinary Medicine, Center for Lung Biology and Disease, Louisiana State University (LSU), Baton Rouge, LA, 70803, USA
| | - Liliang Jin
- Department of Pathobiological Sciences, School of Veterinary Medicine, Center for Lung Biology and Disease, Louisiana State University (LSU), Baton Rouge, LA, 70803, USA
| | - Samithamby Jeyaseelan
- Department of Pathobiological Sciences, School of Veterinary Medicine, Center for Lung Biology and Disease, Louisiana State University (LSU), Baton Rouge, LA, 70803, USA.
- Section of Pulmonary and Critical Care, Department of Medicine, LSU Health Sciences Center, New Orleans, LA, 70112, USA.
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Park CK, Horton NC. Structures, functions, and mechanisms of filament forming enzymes: a renaissance of enzyme filamentation. Biophys Rev 2019; 11:927-994. [PMID: 31734826 PMCID: PMC6874960 DOI: 10.1007/s12551-019-00602-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022] Open
Abstract
Filament formation by non-cytoskeletal enzymes has been known for decades, yet only relatively recently has its wide-spread role in enzyme regulation and biology come to be appreciated. This comprehensive review summarizes what is known for each enzyme confirmed to form filamentous structures in vitro, and for the many that are known only to form large self-assemblies within cells. For some enzymes, studies describing both the in vitro filamentous structures and cellular self-assembly formation are also known and described. Special attention is paid to the detailed structures of each type of enzyme filament, as well as the roles the structures play in enzyme regulation and in biology. Where it is known or hypothesized, the advantages conferred by enzyme filamentation are reviewed. Finally, the similarities, differences, and comparison to the SgrAI endonuclease system are also highlighted.
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Affiliation(s)
- Chad K. Park
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
| | - Nancy C. Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
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37
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Matsushima N, Takatsuka S, Miyashita H, Kretsinger RH. Leucine Rich Repeat Proteins: Sequences, Mutations, Structures and Diseases. Protein Pept Lett 2019; 26:108-131. [PMID: 30526451 DOI: 10.2174/0929866526666181208170027] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/26/2018] [Accepted: 11/26/2018] [Indexed: 12/18/2022]
Abstract
Mutations in the genes encoding Leucine Rich Repeat (LRR) containing proteins are associated with over sixty human diseases; these include high myopia, mitochondrial encephalomyopathy, and Crohn's disease. These mutations occur frequently within the LRR domains and within the regions that shield the hydrophobic core of the LRR domain. The amino acid sequences of fifty-five LRR proteins have been published. They include Nod-Like Receptors (NLRs) such as NLRP1, NLRP3, NLRP14, and Nod-2, Small Leucine Rich Repeat Proteoglycans (SLRPs) such as keratocan, lumican, fibromodulin, PRELP, biglycan, and nyctalopin, and F-box/LRR-repeat proteins such as FBXL2, FBXL4, and FBXL12. For example, 363 missense mutations have been identified. Replacement of arginine, proline, or cysteine by another amino acid, or the reverse, is frequently observed. The diverse effects of the mutations are discussed based on the known structures of LRR proteins. These mutations influence protein folding, aggregation, oligomerization, stability, protein-ligand interactions, disulfide bond formation, and glycosylation. Most of the mutations cause loss of function and a few, gain of function.
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Affiliation(s)
- Norio Matsushima
- Center for Medical Education, Sapporo Medical University, Sapporo 060-8556, Japan.,Institute of Tandem Repeats, Noboribetsu 059-0464, Japan
| | - Shintaro Takatsuka
- Center for Medical Education, Sapporo Medical University, Sapporo 060-8556, Japan
| | - Hiroki Miyashita
- Institute of Tandem Repeats, Noboribetsu 059-0464, Japan.,Hokubu Rinsho Co., Ltd, Sapporo 060-0061, Japan
| | - Robert H Kretsinger
- Department of Biology, University of Virginia, Charlottesville, VA 22904, United States
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38
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de Alba E. Structure, interactions and self-assembly of ASC-dependent inflammasomes. Arch Biochem Biophys 2019; 670:15-31. [PMID: 31152698 PMCID: PMC8455077 DOI: 10.1016/j.abb.2019.05.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/10/2019] [Accepted: 05/28/2019] [Indexed: 12/12/2022]
Abstract
The inflammasome is a multi-protein platform that assembles upon the presence of cues derived from infection or tissue damage, and triggers the inflammatory response. Inflammasome components include sensor proteins that detect danger signals, procaspase 1 and the adapter ASC (apoptosis-associated speck-like protein containing a CARD) tethering these molecules together. Upon inflammasome assembly, procaspase 1 self-activates and renders functional cytokines to arbitrate in the defense mechanism. This assembly is mediated by self-association and protein interactions via Death Domains. The inflammasome plays a critical role in innate immunity and its dysregulation is the culprit of many autoimmune disorders. An in-depth understanding of the factors involved in inflammasome assembly could help fight these conditions. This review describes our current knowledge on the biophysical aspects of inflammasome formation from the perspective of ASC. The specific characteristics of the three-dimensional solution structure and interdomain dynamics of ASC are explained in relation to its function in inflammasome assembly. Additionally, the review elaborates on the identification of ASC interacting surfaces at the amino acid level using NMR techniques. Finally, the macrostructures formed by full-length ASC and its two Death Domains studied with Transmission Electron Microscopy are compared in the context of a directional model for inflammasome assembly.
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Affiliation(s)
- Eva de Alba
- Department of Bioengineering. School of Engineering. University of California, Merced, 5200 North Lake Road, Merced, CA, 95343, USA.
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39
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Viewing Legionella pneumophila Pathogenesis through an Immunological Lens. J Mol Biol 2019; 431:4321-4344. [PMID: 31351897 DOI: 10.1016/j.jmb.2019.07.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/25/2019] [Accepted: 07/13/2019] [Indexed: 12/14/2022]
Abstract
Legionella pneumophila is the causative agent of the severe pneumonia Legionnaires' disease. L. pneumophila is ubiquitously found in freshwater environments, where it replicates within free-living protozoa. Aerosolization of contaminated water supplies allows the bacteria to be inhaled into the human lung, where L. pneumophila can be phagocytosed by alveolar macrophages and replicate intracellularly. The Dot/Icm type IV secretion system (T4SS) is one of the key virulence factors required for intracellular bacterial replication and subsequent disease. The Dot/Icm apparatus translocates more than 300 effector proteins into the host cell cytosol. These effectors interfere with a variety of cellular processes, thus enabling the bacterium to evade phagosome-lysosome fusion and establish an endoplasmic reticulum-derived Legionella-containing vacuole, which facilitates bacterial replication. In turn, the immune system has evolved numerous strategies to recognize intracellular bacteria such as L. pneumophila, leading to potent inflammatory responses that aid in eliminating infection. This review aims to provide an overview of L. pneumophila pathogenesis in the context of the host immune response.
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40
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Wang T, Yan B, Lou L, Lin X, Yu T, Wu S, Lu Q, Liu W, Huang Z, Zhang M, Zhang W, Wen Z. Nlrc3-like is required for microglia maintenance in zebrafish. J Genet Genomics 2019; 46:291-299. [PMID: 31278008 DOI: 10.1016/j.jgg.2019.06.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 06/17/2019] [Accepted: 06/17/2019] [Indexed: 01/06/2023]
Abstract
Microglia are tissue-resident macrophages residing in the central nervous system (CNS) and play critical roles in removing cellular debris and infectious agents as well as regulating neurogenesis and neuronal activities. Yet, the molecular basis underlying the establishment of microglia pool and the maintenance of their homeostasis in the CNS remain largely undefined. Here we report the identification and characterization of a mutant zebrafish, which harbors a point mutation in the nucleotide-binding oligomerization domain (NOD) like receptor gene nlrc3-like, resulting in the loss of microglia in a temperature sensitive manner. Temperature shift assay reveals that the late onset of nlrc3-like deficiency leads to excessive microglia cell death. Further analysis shows that the excessive microglia death in nlrc3-like deficient mutants is attributed, at least in part, to aberrant activation of canonical inflammasome pathway. Our study indicates that proper regulation of inflammasome cascade is critical for the maintenance of microglia homeostasis.
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Affiliation(s)
- Tienan Wang
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China; Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Bo Yan
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China; Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
| | - Liang Lou
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China
| | - Xi Lin
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China
| | - Tao Yu
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China
| | - Shuting Wu
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China
| | - Qing Lu
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Wei Liu
- Department of Developmental Biology, School of Basic Medical Sciences, South China University of Technology, Guangzhou, 510630, China
| | - Zhibin Huang
- Department of Developmental Biology, School of Basic Medical Sciences, South China University of Technology, Guangzhou, 510630, China
| | - Mingjie Zhang
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China
| | - Wenqing Zhang
- Department of Developmental Biology, School of Basic Medical Sciences, South China University of Technology, Guangzhou, 510630, China.
| | - Zilong Wen
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China.
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41
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Abstract
The inflammasome is a multi-molecular platform crucial to the induction of an inflammatory response to cellular danger. Recognition in the cytoplasm of endogenously and exogenously derived ligands initiates conformational change in sensor proteins, such as NLRP3, that permits the subsequent rapid recruitment of adaptor proteins, like ASC, and the resulting assembly of a large-scale inflammatory signalling platform. The assembly process is driven by sensor-sensor interactions as well as sensor-adaptor and adaptor-adaptor interactions. The resulting complex, which can reach diameters of around 1 micron, has a variable composition and stoichiometry. The inflammasome complex functions as a platform for the proximity induced activation of effector caspases, such as caspase-1 and caspase-8. This ultimately leads to the processing of the inflammatory cytokines pro-IL1β and pro-IL18 into their active forms, along with the cleavage of Gasdermin D, a key activator of cell death via pyroptosis.
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42
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Dos Reis EC, Leal VNC, Soares JLDS, Fernandes FP, Souza de Lima D, de Alencar BC, Pontillo A. Flagellin/NLRC4 Pathway Rescues NLRP3-Inflammasome Defect in Dendritic Cells From HIV-Infected Patients: Perspective for New Adjuvant in Immunocompromised Individuals. Front Immunol 2019; 10:1291. [PMID: 31244842 PMCID: PMC6579915 DOI: 10.3389/fimmu.2019.01291] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 05/21/2019] [Indexed: 12/27/2022] Open
Abstract
Introduction: NLRP3 inflammasome plays a key role in dendritic cells (DC) activation in response to vaccine adjuvants, however we previously showed that it is not properly activated in DC from HIV-infected patients (HIV-DC), explaining, at least in part, the poor response to immunization of these patients. Taking in account that several cytoplasmic receptors are able to activate inflammasome, and that bacterial components are considered as a novel and efficient adjuvant, we postulated that bacterial flagellin (FLG), a natural ligand of NAIP/NLRC4 inflammasome, could rescue the activation of the complex in HIV-DC. Objective: Demonstrate that FLG is able to activate monocyte-derived dendritic cells from HIV-infected individuals better than LPS, and to what extent the entity of inflammasome activation differs between DC from HIV-infected patients and healthy donors. Methods: Monocyte-derived dendritic cells from HIV-infected patients (HIV-DC) and healthy donors (HD-DC) were stimulated with FLG, and inflammasome as well as DC activation (phenotypic profile, cytokine production, autologous lymphocytes activation) were compared. Chemical and genetic inhibitors were used to depict the relative contribution of NLRC4 and NLRP3 in HIV/HD-DC response to FLG. Results: FLG properly activates HD-DC and HIV-DC. FLG induces higher inflammasome activation than LPS in HIV-DC. FLG acts through NLRC4 and NLRP3 in HD-DC, but at a lesser extent in HIV-DC due to intrinsic NLRP3 defect. Conclusions: FLG by-passes NLRP3 defect in HIV-DC, through the activation of NAIP/NLRC4 inflammasome, indicating possible future use of the bacterial component as an efficient adjuvant in immunocompromised individuals.
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Affiliation(s)
- Edione Cristina Dos Reis
- Laboratory of Immunogenetics, Department of Immunology, Institute of Biomedical Sciences/ICB, University of São Paulo/USP, São Paulo, Brazil
| | - Vinícius Nunes Cordeiro Leal
- Laboratory of Immunogenetics, Department of Immunology, Institute of Biomedical Sciences/ICB, University of São Paulo/USP, São Paulo, Brazil
| | - Jaíne Lima da Silva Soares
- Laboratory of Immunogenetics, Department of Immunology, Institute of Biomedical Sciences/ICB, University of São Paulo/USP, São Paulo, Brazil
| | - Fernanda Pereira Fernandes
- Laboratory of Immunogenetics, Department of Immunology, Institute of Biomedical Sciences/ICB, University of São Paulo/USP, São Paulo, Brazil
| | - Dhêmerson Souza de Lima
- Laboratory of Immunogenetics, Department of Immunology, Institute of Biomedical Sciences/ICB, University of São Paulo/USP, São Paulo, Brazil
| | - Bruna Cunha de Alencar
- Laboratory of Immune System Cell Biology, Department of Immunology, Institute of Biomedical Sciences/ICB, University of São Paulo/USP, São Paulo, Brazil
| | - Alessandra Pontillo
- Laboratory of Immunogenetics, Department of Immunology, Institute of Biomedical Sciences/ICB, University of São Paulo/USP, São Paulo, Brazil
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43
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Fusco WG, Duncan JA. Novel aspects of the assembly and activation of inflammasomes with focus on the NLRC4 inflammasome. Int Immunol 2019; 30:183-193. [PMID: 29617808 DOI: 10.1093/intimm/dxy009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 02/13/2018] [Indexed: 12/31/2022] Open
Abstract
Inflammasomes are multiprotein structures that activate caspase-1, support secretion of pro-inflammatory cytokines, IL-1β and IL-18, and also induce inflammatory programmed cell death, termed pyoptosis. Inflammasomes are activated in response to the detection of endogenous and microbially derived danger signals and are mediated by several classes of inflammasome-forming sensors. These include several nucleotide-binding proteins of the NOD-like receptor (NLR) family, including NLRP1, NLRP3 and NLRC4, as well as the proteins Absent in Melanoma 2 (AIM2) and Pyrin. Mutations in genes encoding some of these sensors have been found to be associated with gain-of-function monogenetic inflammatory disorders in humans. Genetic, biochemical and structural studies have begun to demonstrate how these proteins sense danger signals and to shed light on the step-by-step processes that are necessary for the assembly of inflammasomes, in both physiologic responses to pathogens and potentially in autoinflammatory conditions. Recent biochemical studies of pro-caspase-1 and an adapter protein known as ASC suggest that inflammasomes act to initiate self-generating effector filaments responsible for activating caspase-1 and initiating downstream signaling. These studies have suggested a model of molecular events from sensor activation to inflammasome formation that may describe processes that are universal to inflammasome formation.
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Affiliation(s)
- William G Fusco
- Department of Medicine, Division of Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Joseph A Duncan
- Department of Medicine, Division of Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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44
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Haloupek N, Grob P, Tenthorey J, Vance RE, Nogales E. Cryo-EM studies of NAIP-NLRC4 inflammasomes. Methods Enzymol 2019; 625:177-204. [PMID: 31455527 PMCID: PMC7025759 DOI: 10.1016/bs.mie.2019.04.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The NAIP-NLRC4 family of inflammasomes are components of the innate immune system that sound a molecular alarm in the presence of intracellular pathogens. In this chapter, we provide an in-depth guide to using cryo-electron microscopy (cryo-EM) to investigate these inflammasomes, focusing especially on the techniques we used in our recent structural analysis of the NAIP5-NLRC4 inflammasome. We explain how to circumvent specific obstacles we encountered at each step, from sample preparation through data processing. The methods described here will be useful for further studies of the NAIP5-NLRC4 inflammasome and related supracomplexes involved in innate immune surveillance; they may also be useful for unrelated complexes that present similar issues, such as preferential orientations and compositional heterogeneity.
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Affiliation(s)
- Nicole Haloupek
- Department of Molecular and Cell Biology, UC Berkeley, Berkeley, CA, United States.
| | - Patricia Grob
- Howard Hughes Medical Institute, UC Berkeley, Berkeley, CA, United States
| | - Jeannette Tenthorey
- Department of Molecular and Cell Biology, UC Berkeley, Berkeley, CA, United States
| | - Russell E Vance
- Department of Molecular and Cell Biology, UC Berkeley, Berkeley, CA, United States; Howard Hughes Medical Institute, UC Berkeley, Berkeley, CA, United States
| | - Eva Nogales
- Department of Molecular and Cell Biology, UC Berkeley, Berkeley, CA, United States; Howard Hughes Medical Institute, UC Berkeley, Berkeley, CA, United States; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Lab, Berkeley, CA, United States.
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45
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Shen C, Sharif H, Xia S, Wu H. Structural and mechanistic elucidation of inflammasome signaling by cryo-EM. Curr Opin Struct Biol 2019; 58:18-25. [PMID: 31128494 DOI: 10.1016/j.sbi.2019.03.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/25/2019] [Accepted: 03/27/2019] [Indexed: 10/26/2022]
Abstract
The innate immune system forms an evolutionarily ancient line of defense against invading pathogens and endogenous danger signals. Within certain cells of innate immunity, including epithelial cells and macrophages, intricate molecular machineries named inflammasomes sense a wide array of stimuli to mount inflammatory responses. Dysregulation in inflammasome signaling leads to a wide range of immune disorders such as gout, Crohn's disease, and sepsis. Recent technological advances in cryo-electron microscopy (cryo-EM) have enabled the structural determination of several key signaling molecules in inflammasome pathways, from which macromolecular assembly emerges as a common mechanistic theme. Through the assembly of helical filaments, symmetric disks, and transmembrane pores, inflammasome pathways employ highly dynamic yet ordered processes to relay and amplify signals. These unprecedentedly detailed views of inflammasome signaling not only revolutionize our understanding of inflammation, but also pave the way for the development of therapeutics against inflammatory diseases.
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Affiliation(s)
- Chen Shen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Humayun Sharif
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Shiyu Xia
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
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46
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Animal NLRs continue to inform plant NLR structure and function. Arch Biochem Biophys 2019; 670:58-68. [PMID: 31071301 DOI: 10.1016/j.abb.2019.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/10/2019] [Accepted: 05/01/2019] [Indexed: 12/22/2022]
Abstract
Plant NLRs share many of the structural hallmarks of their animal counterparts. At a functional level, the central nucleotide-binding pocket appears to have binding and hydrolysis activities, similar to that of animal NLRs. The TIR domains of plant NLRs have been shown to self-associate, and there is emerging evidence that full-length plant NLRs may do so as well. It is therefore tempting to speculate that plant NLRs may form higher-order complexes similar to those of the mammalian inflammasome. Here we review the available knowledge on structure-function relationships in plant NLRs, focusing on how the information available on animal NLRs informs the mechanism of plant NLR function, and highlight the evidence that innate immunity signalling pathways in multicellular organisms often require the formation of higher-order protein complexes.
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47
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de Ruiter MV, Klem R, Luque D, Cornelissen JJLM, Castón JR. Structural nanotechnology: three-dimensional cryo-EM and its use in the development of nanoplatforms for in vitro catalysis. NANOSCALE 2019; 11:4130-4146. [PMID: 30793729 DOI: 10.1039/c8nr09204d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The organization of enzymes into different subcellular compartments is essential for correct cell function. Protein-based cages are a relatively recently discovered subclass of structurally dynamic cellular compartments that can be mimicked in the laboratory to encapsulate enzymes. These synthetic structures can then be used to improve our understanding of natural protein-based cages, or as nanoreactors in industrial catalysis, metabolic engineering, and medicine. Since the function of natural protein-based cages is related to their three-dimensional structure, it is important to determine this at the highest possible resolution if viable nanoreactors are to be engineered. Cryo-electron microscopy (cryo-EM) is ideal for undertaking such analyses within a feasible time frame and at near-native conditions. This review describes how three-dimensional cryo-EM is used in this field and discusses its advantages. An overview is also given of the nanoreactors produced so far, their structure, function, and applications.
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Affiliation(s)
- Mark V de Ruiter
- Department of Biomolecular Nanotechnology, MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
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Deng J, Yu XQ, Wang PH. Inflammasome activation and Th17 responses. Mol Immunol 2019; 107:142-164. [PMID: 30739833 DOI: 10.1016/j.molimm.2018.12.024] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 12/24/2022]
Abstract
Immune sensing of exogenous molecules from microbes (e.g., pathogen-associated molecular patterns) and nonmicrobial molecules (e.g., asbestos, alum, and silica), as well as endogenous damage-associated molecular patterns (e.g., ATP, uric acid crystals, and amyloid A) activates innate immunity by inducing immune-related genes, including proinflammatory cytokines, which further facilitate the development of adaptive immunity. The roles of transcriptional responses downstream of immune sensing have been widely characterized in informing adaptive immunity; however, few studies focus on the effect of post-translational responses on the modulation of adaptive immune responses. Inflammasomes activated by the previously described endo- and exogenous stimuli autocatalytically induce intracellular pro-caspase-1, which cleaves the inactive precursors of interleukin-1β (IL-1β) and IL-18 into bioactive proinflammatory cytokines. IL-1β and IL-18 not only contribute to the host defense against infections by activating phagocytes, such as monocytes, macrophages, dendritic cells, and neutrophils, but also induce T-helper 17 (Th17)- and Th1-mediated adaptive immune responses. In synergy with IL-6 and IL-23, IL-1β activates IL-1 receptor (IL-1R) signaling to drive the differentiation of IL-17-producing Th17 cells, which not only play critical roles in host protective immunity to infections of bacteria, fungi, and certain viruses but also participate in the pathology of inflammatory disorders and tumorigenesis. Consequently, targeting inflammasomes and IL-1/IL-1R signaling may effectively improve the treatment of Th17-associated disorders, such as autoinflammatory diseases and cancers, thereby providing novel insights into drug development.
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Affiliation(s)
- Jian Deng
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Xiao-Qiang Yu
- School of Biological Sciences, University of Missouri - Kansas City, Kansas City, MO, 64110-2499, USA
| | - Pei-Hui Wang
- Advanced Medical Research Institute, Shandong University, Jinan, Shandong 250012, China; School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong.
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Abstract
Inflammasomes are large protein complexes that trigger host defense in cells by activating inflammatory caspases for cytokine maturation and pyroptosis. NLRP6 is a sensor protein in the nucleotide-binding domain (NBD) and leucine-rich repeat (LRR)-containing (NLR) inflammasome family that has been shown to play multiple roles in regulating inflammation and host defenses. Despite the significance of the NLRP6 inflammasome, little is known about the molecular mechanism behind its assembly and activation. Here we present cryo-EM and crystal structures of NLRP6 pyrin domain (PYD). We show that NLRP6 PYD alone is able to self-assemble into filamentous structures accompanied by large conformational changes and can recruit the ASC adaptor using PYD-PYD interactions. Using molecular dynamics simulations, we identify the surface that the NLRP6 PYD filament uses to recruit ASC PYD. We further find that full-length NLRP6 assembles in a concentration-dependent manner into wider filaments with a PYD core surrounded by the NBD and the LRR domain. These findings provide a structural understanding of inflammasome assembly by NLRP6 and other members of the NLR family.
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Maharana J, Panda D, De S. Deciphering the ATP-binding mechanism(s) in NLRP-NACHT 3D models using structural bioinformatics approaches. PLoS One 2018; 13:e0209420. [PMID: 30571723 PMCID: PMC6301626 DOI: 10.1371/journal.pone.0209420] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 12/05/2018] [Indexed: 01/04/2023] Open
Abstract
Nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs), the first line of defense, are the cytosolic pattern recognition receptors (PRRs) that regulate the inflammatory activity in response to invading pathogens. NLRs are the members of AAA+ ATPase superfamily that comprises of N-terminal EBD(s), a centrally positioned NOD/NACHT and varying range of LRRs towards the C-terminal end. Due to the lack of structural data, the functional aspects of NLRP-signaling mechanism, which includes pathogen recognition, nucleotide-binding, and sensor-adaptor-effector interactions, are not fully understood. In this study, we implemented structural bioinformatics approaches including protein modeling, docking, and molecular dynamics simulations to explore the structural-dynamic features of ADP-/ATP-Mg2+ binding in NLRPNACHT models. Our results indicate a similar mode of ATP-Mg2+ binding in all NLRPNACHT models and the interacting residues are found consistent with reported mutagenesis data. Accompanied by the key amino acids (proposed to be crucial for ATP-Mg2+ coordination), we further have noticed that some additional conserved residues (including 'Trp' of the PhhCW motif, and 'Phe' and 'Tyr' of the GFxxxxRxxYF motif) are potentially interacting with ATP during dynamics; which require further experimentation for legitimacy. Overall, this study will help in understanding the ADP-/ATP-Mg2+ binding mechanisms in NLRPs in a broader perspective and the proposed ATP-binding pocket will aid in designing novel inhibitors for the regulation of inflammasome activity.
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Affiliation(s)
- Jitendra Maharana
- Department of Bioinformatics, Orissa University of Agriculture and Technology, Bhubaneswar, Odisha, India
- * E-mail: (JM); (SD)
| | - Debashis Panda
- Distributed Information Centre (DIC), Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, India
| | - Sachinandan De
- Animal Genomics Lab., Animal Biotechnology Centre, ICAR-National Dairy Research Institute, Karnal, Haryana, India
- * E-mail: (JM); (SD)
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