1
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Nataraj NM, Sillas RG, Herrmann BI, Shin S, Brodsky IE. Blockade of IKK signaling induces RIPK1-independent apoptosis in human macrophages. PLoS Pathog 2024; 20:e1012469. [PMID: 39186805 DOI: 10.1371/journal.ppat.1012469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 07/31/2024] [Indexed: 08/28/2024] Open
Abstract
Regulated cell death in response to microbial infection plays an important role in immune defense and is triggered by pathogen disruption of essential cellular pathways. Gram-negative bacterial pathogens in the Yersinia genus disrupt NF-κB signaling via translocated effectors injected by a type III secretion system, thereby preventing induction of cytokine production and antimicrobial defense. In murine models of infection, Yersinia blockade of NF-κB signaling triggers cell-extrinsic apoptosis through Receptor Interacting Serine-Threonine Protein Kinase 1 (RIPK1) and caspase-8, which is required for bacterial clearance and host survival. Unexpectedly, we find that human macrophages undergo apoptosis independently of RIPK1 in response to Yersinia or chemical blockade of IKKβ. Instead, IKK blockade led to decreased cFLIP expression, and overexpression of cFLIP contributed to protection from IKK blockade-induced apoptosis in human macrophages. We found that IKK blockade also induces RIPK1 kinase activity-independent apoptosis in human T cells and human pancreatic cells. Altogether, our data indicate that, in contrast to murine cells, blockade of IKK activity in human cells triggers a distinct apoptosis pathway that is independent of RIPK1 kinase activity. These findings have implications for the contribution of RIPK1 to cell death in human cells and the efficacy of RIPK1 inhibition in human diseases.
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Affiliation(s)
- Neha M Nataraj
- Institute for Immunology & Immune Health, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Reyna Garcia Sillas
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
| | - Beatrice I Herrmann
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
| | - Sunny Shin
- Institute for Immunology & Immune Health, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Igor E Brodsky
- Institute for Immunology & Immune Health, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
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2
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Wu Q, Du J, Bae EJ, Choi Y. Pyroptosis in Skeleton Diseases: A Potential Therapeutic Target Based on Inflammatory Cell Death. Int J Mol Sci 2024; 25:9068. [PMID: 39201755 PMCID: PMC11354934 DOI: 10.3390/ijms25169068] [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: 06/25/2024] [Revised: 08/15/2024] [Accepted: 08/20/2024] [Indexed: 09/03/2024] Open
Abstract
Skeletal disorders, including fractures, osteoporosis, osteoarthritis, rheumatoid arthritis, and spinal degenerative conditions, along with associated spinal cord injuries, significantly impair daily life and impose a substantial burden. Many of these conditions are notably linked to inflammation, with some classified as inflammatory diseases. Pyroptosis, a newly recognized form of inflammatory cell death, is primarily triggered by inflammasomes and executed by caspases, leading to inflammation and cell death through gasdermin proteins. Emerging research underscores the pivotal role of pyroptosis in skeletal disorders. This review explores the pyroptosis signaling pathways and their involvement in skeletal diseases, the modulation of pyroptosis by other signals in these conditions, and the current evidence supporting the therapeutic potential of targeting pyroptosis in treating skeletal disorders, aiming to offer novel insights for their management.
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Affiliation(s)
- Qian Wu
- Department of Biochemistry and Molecular Biology, Jeonbuk National University Medical School, Jeonju 54896, Republic of Korea (J.D.)
| | - Jiacheng Du
- Department of Biochemistry and Molecular Biology, Jeonbuk National University Medical School, Jeonju 54896, Republic of Korea (J.D.)
| | - Eun Ju Bae
- School of Pharmacy, Jeonbuk National University, Jeonju 54896, Republic of Korea
| | - Yunjung Choi
- Division of Rheumatology, Department of Internal Medicine, Jeonbuk National University Medical School, Jeonju 54896, Republic of Korea
- Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju 54907, Republic of Korea
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3
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Tweedell RE, Kanneganti TD. Inflammasomes at the Foundation of Inflammatory Cell Death Complexes. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 213:247-249. [PMID: 39008793 PMCID: PMC11302449 DOI: 10.4049/jimmunol.2400288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Accepted: 05/21/2024] [Indexed: 07/17/2024]
Abstract
This Pillars of Immunology article is a commentary on “The Inflammasome: A Molecular Platform Triggering Activation of Inflammatory Caspases and Processing of proIL-β,” a pivotal article written by F. Martinon, K. Burns, and J. Tschopp, published in Molecular Cell in 2002. https://doi.org/10.1016/S1097-2765(02)00599-3.
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Affiliation(s)
- Rebecca E Tweedell
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
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4
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Sundaram B, Pandian N, Kim HJ, Abdelaal HM, Mall R, Indari O, Sarkar R, Tweedell RE, Alonzo EQ, Klein J, Pruett-Miller SM, Vogel P, Kanneganti TD. NLRC5 senses NAD + depletion, forming a PANoptosome and driving PANoptosis and inflammation. Cell 2024; 187:4061-4077.e17. [PMID: 38878777 PMCID: PMC11283362 DOI: 10.1016/j.cell.2024.05.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 04/01/2024] [Accepted: 05/17/2024] [Indexed: 07/28/2024]
Abstract
NLRs constitute a large, highly conserved family of cytosolic pattern recognition receptors that are central to health and disease, making them key therapeutic targets. NLRC5 is an enigmatic NLR with mutations associated with inflammatory and infectious diseases, but little is known about its function as an innate immune sensor and cell death regulator. Therefore, we screened for NLRC5's role in response to infections, PAMPs, DAMPs, and cytokines. We identified that NLRC5 acts as an innate immune sensor to drive inflammatory cell death, PANoptosis, in response to specific ligands, including PAMP/heme and heme/cytokine combinations. NLRC5 interacted with NLRP12 and PANoptosome components to form a cell death complex, suggesting an NLR network forms similar to those in plants. Mechanistically, TLR signaling and NAD+ levels regulated NLRC5 expression and ROS production to control cell death. Furthermore, NLRC5-deficient mice were protected in hemolytic and inflammatory models, suggesting that NLRC5 could be a potential therapeutic target.
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Affiliation(s)
- Balamurugan Sundaram
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Nagakannan Pandian
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Hee Jin Kim
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Hadia M Abdelaal
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Raghvendra Mall
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Omkar Indari
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Roman Sarkar
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Rebecca E Tweedell
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Emily Q Alonzo
- Department of Research and Development, Cell Signaling Technology, Danvers, MA 01915, USA
| | - Jonathon Klein
- Center for Advanced Genome Engineering, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Shondra M Pruett-Miller
- Center for Advanced Genome Engineering, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Peter Vogel
- Animal Resources Center and the Veterinary Pathology Core, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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5
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Huang X, Li C, Zhang K, Li K, Xie J, Peng Y, Quan M, Sun Y, Hu Y, Xia L, Hu S. Function and Global Regulation of Type III Secretion System and Flagella in Entomopathogenic Nematode Symbiotic Bacteria. Int J Mol Sci 2024; 25:7579. [PMID: 39062822 PMCID: PMC11277461 DOI: 10.3390/ijms25147579] [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: 06/21/2024] [Revised: 07/06/2024] [Accepted: 07/08/2024] [Indexed: 07/28/2024] Open
Abstract
Currently, it is widely accepted that the type III secretion system (T3SS) serves as the transport platform for bacterial virulence factors, while flagella act as propulsion motors. However, there remains a noticeable dearth of comparative studies elucidating the functional disparities between these two mechanisms. Entomopathogenic nematode symbiotic bacteria (ENS), including Xenorhabdus and Photorhabdus, are Gram-negative bacteria transported into insect hosts by Steinernema or Heterorhabdus. Flagella are conserved in ENS, but the T3SS is only encoded in Photorhabdus. There are few reports on the function of flagella and the T3SS in ENS, and it is not known what role they play in the infection of ENS. Here, we clarified the function of the T3SS and flagella in ENS infection based on flagellar inactivation in X. stockiae (flhDC deletion), T3SS inactivation in P. luminescens (sctV deletion), and the heterologous synthesis of the T3SS of P. luminescens in X. stockiae. Consistent with the previous results, the swarming movement of the ENS and the formation of biofilms are dominated by the flagella. Both the T3SS and flagella facilitate ENS invasion and colonization within host cells, with minimal impact on secondary metabolite formation and secretion. Unexpectedly, a proteomic analysis reveals a negative feedback loop between the flagella/T3SS assembly and the type VI secretion system (T6SS). RT-PCR testing demonstrates the T3SS's inhibition of flagellar assembly, while flagellin expression promotes T3SS assembly. Furthermore, T3SS expression stimulates ribosome-associated protein expression.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Shengbiao Hu
- State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Provincial Key Laboratory of Microbial Molecular Biology, College of Life Science, Hunan Normal University, Changsha 410081, China; (X.H.); (K.L.); (L.X.)
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6
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Conte AN, Ridgeway SM, Ruchel ME, Kibby EM, Nagy TA, Whiteley AT. Phage detection by a bacterial NLR-related protein is mediated by DnaJ. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.04.597415. [PMID: 38895412 PMCID: PMC11185742 DOI: 10.1101/2024.06.04.597415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Bacteria encode a wide range of antiphage systems and a subset of these proteins are homologous to components of the human innate immune system. Mammalian nucleotide-binding and leucine-rich repeat containing proteins (NLRs) and bacterial NLR-related proteins use a central NACHT domain to link infection detection with initiation of an antimicrobial response. Bacterial NACHT proteins provide defense against both DNA and RNA phages. Here we determine the mechanism of RNA phage detection by the bacterial NLR-related protein bNACHT25 in E. coli. bNACHT25 was specifically activated by Emesvirus ssRNA phages and analysis of MS2 phage suppressor mutants that evaded detection revealed Coat Protein (CP) was sufficient for activation. bNACHT25 and CP did not physically interact. Instead, we found bNACHT25 requires the host chaperone DnaJ to detect CP. Our data suggest that bNACHT25 detects a wide range of phages by guarding a host cell process rather than binding a specific phage-derived molecule.
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Affiliation(s)
- Amy N. Conte
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | | | - Madison E. Ruchel
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
- Department of Biology, Front Range Community College, Longmont, CO, USA
| | - Emily M. Kibby
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Toni A. Nagy
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Aaron T. Whiteley
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
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7
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Jastrab JB, Kagan JC. Strategies of bacterial detection by inflammasomes. Cell Chem Biol 2024; 31:835-850. [PMID: 38636521 PMCID: PMC11103797 DOI: 10.1016/j.chembiol.2024.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/09/2024] [Accepted: 03/26/2024] [Indexed: 04/20/2024]
Abstract
Mammalian innate immunity is regulated by pattern-recognition receptors (PRRs) and guard proteins, which use distinct strategies to detect infections. PRRs detect bacterial molecules directly, whereas guards detect host cell manipulations by microbial virulence factors. Despite sensing infection through different mechanisms, both classes of innate immune sensors can activate the inflammasome, an immune complex that can mediate cell death and inflammation. Inflammasome-mediated immune responses are crucial for host defense against many bacterial pathogens and prevent invasion by non-pathogenic organisms. In this review, we discuss the mechanisms by which inflammasomes are stimulated by PRRs and guards during bacterial infection, and the strategies used by virulent bacteria to evade inflammasome-mediated immunity.
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Affiliation(s)
- Jordan B Jastrab
- Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA; Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Jonathan C Kagan
- Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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8
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Doedens JR, Smolak P, Nguyen M, Wescott H, Diamond C, Schooley K, Billinton A, Harrison D, Koller BH, Watt AP, Gabel CA. Pharmacological Analysis of NLRP3 Inflammasome Inhibitor Sodium [(1,2,3,5,6,7-Hexahydro-s-indacen-4-yl)carbamoyl][(1-methyl-1 H-pyrazol-4-yl)({[(2 S)-oxolan-2-yl]methyl})sulfamoyl]azanide in Cellular and Mouse Models of Inflammation Provides a Translational Framework. ACS Pharmacol Transl Sci 2024; 7:1438-1456. [PMID: 38751618 PMCID: PMC11091978 DOI: 10.1021/acsptsci.4c00061] [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: 02/05/2024] [Revised: 03/19/2024] [Accepted: 04/09/2024] [Indexed: 05/18/2024]
Abstract
Interleukin (IL)-1β is an apex proinflammatory cytokine produced in response to tissue injury and infection. The output of IL-1β from monocytes and macrophages is regulated not only by transcription and translation but also post-translationally. Release of the active cytokine requires activation of inflammasomes, which couple IL-1β post-translational proteolysis with pyroptosis. Among inflammasome platforms, NOD-like receptor pyrin domain-containing protein 3 (NLRP3) is implicated in the pathogenesis of numerous human disorders in which disease-specific danger-associated molecular patterns (DAMPS) are positioned to drive its activation. As a promising therapeutic target, numerous candidate NLRP3-targeting therapeutics have been described and demonstrated to provide benefits in the context of animal disease models. While showing benefits, published preclinical studies have not explored dose-response relationships within the context of the models. Here, the preclinical pharmacology of a new chemical entity, [(1,2,3,5,6,7-hexahydro-s-indacen-4-yl)carbamoyl][(1-methyl-1H-pyrazol-4-yl)({[(2S)-oxolan-2-yl]methyl})sulfamoyl]azanide (NT-0249), is detailed, establishing its potency and selectivity as an NLRP3 inhibitor. NT-0249 also is evaluated in two acute in vivo mouse challenge models where pharmacodynamic/pharmacokinetic relationships align well with in vitro blood potency assessments. The therapeutic utility of NT-0249 is established in a mouse model of cryopyrin-associated periodic syndrome (CAPS). In this model, mice express a human gain-of-function NLRP3 allele and develop chronic and progressive IL-1β-dependent autoinflammatory disease. NT-0249 dose-dependently reduced multiple inflammatory biomarkers in this model. Significantly, NT-0249 decreased mature IL-1β levels in tissue homogenates, confirming in vivo target engagement. Our findings highlight not only the pharmacological attributes of NT-0249 but also provide insight into the extent of target suppression that will be required to achieve clinical benefit.
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Affiliation(s)
| | - Pamela Smolak
- NodThera,
Inc., Seattle, Washington 98103, United States
| | - MyTrang Nguyen
- Department
of Genetics, University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27599, United States
| | | | | | - Ken Schooley
- NodThera,
Inc., Seattle, Washington 98103, United States
| | - Andy Billinton
- NodThera
Ltd, Little Chesterford,
Saffron Walden, Essex CB10
1XL, U.K.
| | - David Harrison
- NodThera
Ltd, Little Chesterford,
Saffron Walden, Essex CB10
1XL, U.K.
| | - Beverly H. Koller
- Department
of Genetics, University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27599, United States
| | - Alan P. Watt
- NodThera
Ltd, Little Chesterford,
Saffron Walden, Essex CB10
1XL, U.K.
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9
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Lovelace-Macon L, Baker SM, Ducken D, Seal S, Rerolle G, Tomita D, Smith KD, Schwarz S, West TE. Flagellin-modulated inflammasome pathways characterize the human alveolar macrophage response to Burkholderia pseudomallei, a lung-tropic pathogen. Infect Immun 2024; 92:e0006024. [PMID: 38619302 PMCID: PMC11075458 DOI: 10.1128/iai.00060-24] [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: 02/02/2024] [Accepted: 03/15/2024] [Indexed: 04/16/2024] Open
Abstract
Melioidosis is an emerging tropical infection caused by inhalation, inoculation, or ingestion of the flagellated, facultatively intracellular pathogen Burkholderia pseudomallei. The melioidosis case fatality rate is often high, and pneumonia, the most common presentation, doubles the risk of death. The alveolar macrophage is a sentinel pulmonary host defense cell, but the human alveolar macrophage in B. pseudomallei infection has never been studied. The objective of this study was to investigate the host-pathogen interaction of B. pseudomallei infection with the human alveolar macrophage and to determine the role of flagellin in modulating inflammasome-mediated pathways. We found that B. pseudomallei infects primary human alveolar macrophages but is gradually restricted in the setting of concurrent cell death. Electron microscopy revealed cytosolic bacteria undergoing division, indicating that B. pseudomallei likely escapes the alveolar macrophage phagosome and may replicate in the cytosol, where it triggers immune responses. In paired human blood monocytes, uptake and intracellular restriction of B. pseudomallei are similar to those observed in alveolar macrophages, but cell death is reduced. The alveolar macrophage cytokine response to B. pseudomallei is characterized by marked interleukin (IL)-18 secretion compared to monocytes. Both cytotoxicity and IL-18 secretion in alveolar macrophages are partially flagellin dependent. However, the proportion of IL-18 release that is driven by flagellin is greater in alveolar macrophages than in monocytes. These findings suggest differential flagellin-mediated inflammasome pathway activation in the human alveolar macrophage response to B. pseudomallei infection and expand our understanding of intracellular pathogen recognition by this unique innate immune lung cell.
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Affiliation(s)
- Lara Lovelace-Macon
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Sarah M. Baker
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Deirdre Ducken
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Sudeshna Seal
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Guilhem Rerolle
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Diane Tomita
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Kelly D. Smith
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Sandra Schwarz
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tuebingen, Tuebingen, Germany
| | - T. Eoin West
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
- Department of Global Health, University of Washington, Seattle, Washington, USA
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10
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Yu J, Zhao Z, Li Y, Chen J, Huang N, Luo Y. Role of NLRP3 in Parkinson's disease: Specific activation especially in dopaminergic neurons. Heliyon 2024; 10:e28838. [PMID: 38596076 PMCID: PMC11002585 DOI: 10.1016/j.heliyon.2024.e28838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 03/22/2024] [Accepted: 03/26/2024] [Indexed: 04/11/2024] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder with motor symptoms like bradykinesia, tremors, and balance issues. The pathology is recognized by progressively degenerative nigrostriatal dopaminergic neurons (DANs) loss. Its exact pathogenesis is unclear. Numerous studies have shown that nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) contributes to the pathogenesis of PD. Previous studies have demonstrated that the over-activation of NLRP3 inflammasome in microglia indirectly leads to the loss of DANs, which can worsen PD. In recent years, autopsy analyses of PD patients and studies in PD models have revealed upregulation of NLRP3 expression within DANs and demonstrated that activation of NLRP3 inflammasome in neurons is sufficient to drive neuronal loss, whereas microglial activation occurs after neuronal death, and that inhibition of intraneuronal NLRP3 inflammasome prevents degeneration of DANs. In this review, we provide research evidence related to NLRP3 inflammasome in DANs in PD as well as focus on possible mechanisms of NLRP3 inflammasome activation in neurons, aiming to provide a new way of thinking about the pathogenesis and prevention of PD.
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Affiliation(s)
- Juan Yu
- Department of Neurology, Third Affiliated Hospital of Zunyi Medical University (The First People's Hospital of Zunyi), Zunyi, 563000, China
| | - Zhanghong Zhao
- Department of Neurology, Third Affiliated Hospital of Zunyi Medical University (The First People's Hospital of Zunyi), Zunyi, 563000, China
| | - Yuanyuan Li
- National Drug Clinical Trial Institution, Third Affiliated Hospital of Zunyi Medical University (The First People's Hospital of Zunyi), Zunyi, Guizhou, China
| | - Jian Chen
- Department of Neurology, Third Affiliated Hospital of Zunyi Medical University (The First People's Hospital of Zunyi), Zunyi, 563000, China
| | - Nanqu Huang
- National Drug Clinical Trial Institution, Third Affiliated Hospital of Zunyi Medical University (The First People's Hospital of Zunyi), Zunyi, Guizhou, China
| | - Yong Luo
- Department of Neurology, Third Affiliated Hospital of Zunyi Medical University (The First People's Hospital of Zunyi), Zunyi, 563000, China
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11
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Sundaram B, Tweedell RE, Prasanth Kumar S, Kanneganti TD. The NLR family of innate immune and cell death sensors. Immunity 2024; 57:674-699. [PMID: 38599165 PMCID: PMC11112261 DOI: 10.1016/j.immuni.2024.03.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/07/2024] [Accepted: 03/12/2024] [Indexed: 04/12/2024]
Abstract
Nucleotide-binding oligomerization domain (NOD)-like receptors, also known as nucleotide-binding leucine-rich repeat receptors (NLRs), are a family of cytosolic pattern recognition receptors that detect a wide variety of pathogenic and sterile triggers. Activation of specific NLRs initiates pro- or anti-inflammatory signaling cascades and the formation of inflammasomes-multi-protein complexes that induce caspase-1 activation to drive inflammatory cytokine maturation and lytic cell death, pyroptosis. Certain NLRs and inflammasomes act as integral components of larger cell death complexes-PANoptosomes-driving another form of lytic cell death, PANoptosis. Here, we review the current understanding of the evolution, structure, and function of NLRs in health and disease. We discuss the concept of NLR networks and their roles in driving cell death and immunity. An improved mechanistic understanding of NLRs may provide therapeutic strategies applicable across infectious and inflammatory diseases and in cancer.
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Affiliation(s)
- Balamurugan Sundaram
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Rebecca E Tweedell
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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12
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Manshouri S, Seif F, Kamali M, Bahar MA, Mashayekh A, Molatefi R. The interaction of inflammasomes and gut microbiota: novel therapeutic insights. Cell Commun Signal 2024; 22:209. [PMID: 38566180 PMCID: PMC10986108 DOI: 10.1186/s12964-024-01504-1] [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] [Received: 09/26/2023] [Accepted: 01/28/2024] [Indexed: 04/04/2024] Open
Abstract
Inflammasomes are complex platforms for the cleavage and release of inactivated IL-1β and IL-18 cytokines that trigger inflammatory responses against damage-associated molecular patterns (DAMPs) or pathogen-associated molecular patterns (PAMPs). Gut microbiota plays a pivotal role in maintaining gut homeostasis. Inflammasome activation needs to be tightly regulated to limit aberrant activation and bystander damage to the host cells. Several types of inflammasomes, including Node-like receptor protein family (e.g., NLRP1, NLRP3, NLRP6, NLRP12, NLRC4), PYHIN family, and pyrin inflammasomes, interact with gut microbiota to maintain gut homeostasis. This review discusses the current understanding of how inflammasomes and microbiota interact, and how this interaction impacts human health. Additionally, we introduce novel biologics and antagonists, such as inhibitors of IL-1β and inflammasomes, as therapeutic strategies for treating gastrointestinal disorders when inflammasomes are dysregulated or the composition of gut microbiota changes.
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Affiliation(s)
- Shirin Manshouri
- Rajaei Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Valiasr St, Niayesh Intersection, Tehran, 1995614331, Iran
| | - Farhad Seif
- Department of Photodynamic Therapy, Medical Laser Research Center, Academic Center for Education, Culture, and Research (ACECR), Tehran, Iran
- Department of Immunology and Allergy, Academic Center for Education, Culture, and Research (ACECR), Tehran, Iran
| | - Monireh Kamali
- Rajaei Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Valiasr St, Niayesh Intersection, Tehran, 1995614331, Iran
| | - Mohammad Ali Bahar
- Department of Immunology, Medical School, Iran University of Medical Sciences, Tehran, Iran
| | - Arshideh Mashayekh
- Rajaei Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Valiasr St, Niayesh Intersection, Tehran, 1995614331, Iran.
| | - Rasol Molatefi
- Cancer Immunology and Immunotherapy Research Center, Ardabil University of Medical Sciences, Ardabil, Iran.
- Pediatric Department of Bou Ali Hospital, Ardabil University of Medical Sciences, Ardabil, 56189-85991, Iran.
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13
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Liao Z, Ji W, Yang C, Su J. TLR5M and TLR5S Synergistically Sense Flagellin in Early Endosome in Lamprey Petromyzon marinus, Switched by the N-Glycosylation Site N239. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 212:855-867. [PMID: 38231121 DOI: 10.4049/jimmunol.2300490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 12/28/2023] [Indexed: 01/18/2024]
Abstract
In mammals, TLR5 functions as a homodimer to recognize bacterial flagellin on the cytomembrane. The current investigations reveal the existence of two types of TLR5, a membrane-bound PmTLR5M, and a soluble variant PmTLR5S, in lamprey (Petromyzon marinus). Although both PmTLR5M and PmTLR5S can bind flagellin, only PmTLR5M is capable of eliciting a proinflammatory response, whereas PmTLR5S can detect the flagellin and facilitate the role of PmTLR5M in early endosomes. The trafficking chaperone UNC93B1 enhances the ligand-induced signaling via PmTLR5M or the combination of PmTLR5M and PmTLR5S. PmTLR5M recruits MyD88 as an adaptor. Furthermore, chimeric receptor studies demonstrate the indispensability of the intradomain of PmTLR5M in effective activation of the proinflammatory pathway upon flagellin stimulation, and the combination of PmTLR5S with a singular intradomain in both homodimer and heterodimer ectodomain arrangements can very significantly augment the immune response. Furthermore, the flagellin binding sites between PmTLR5M and PmTLR5S are conserved, which are essential for ligand binding and signal transduction. Moreover, investigations on N-linked glycosylation modifications reveal that the N239 site in PmTLR5M and PmTLR5S plays a switch role in both flagellin binding and immune responses. In addition, PmTLR5M exhibits the high-mannose-type and complex-type N-glycosylation modifications; however, PmTLR5S shows exclusive complex-type N-glycosylation modification. The key N239 site demonstrates complex-type N-glycosylation modification. The findings address the function and mechanism of TLR5 in ligand recognition, subcellular localization, and signaling pathway in lowest vertebrate and immune system transition species, highlight the regulatory role of N-glycosylation modification in TLRs, and augment immune evolutionary research on the TLR signaling pathway.
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Affiliation(s)
- Zhiwei Liao
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Wei Ji
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan, China
| | - Chunrong Yang
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Jianguo Su
- Hubei Hongshan Laboratory, College of Fisheries, Huazhong Agricultural University, Wuhan, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
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14
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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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15
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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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16
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Paidimuddala B, Cao J, Zhang L. Structural basis for flagellin-induced NAIP5 activation. SCIENCE ADVANCES 2023; 9:eadi8539. [PMID: 38055825 PMCID: PMC10699770 DOI: 10.1126/sciadv.adi8539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Accepted: 11/06/2023] [Indexed: 12/08/2023]
Abstract
The NAIP (NLR family apoptosis inhibitory protein)/NLRC4 (NLR family CARD containing protein 4) inflammasome senses Gram-negative bacterial ligand. In the ligand-bound state, the winged helix domain of NAIP forms a steric clash with NLRC4 to open it up. However, how ligand binding activates NAIP is less clear. Here, we investigated the dynamics of the ligand-binding region of inactive NAIP5 and solved the cryo-EM structure of NAIP5 in complex with its specific ligand, FliC from flagellin, at 2.9-Å resolution. The structure revealed a "trap and lock" mechanism in FliC recognition, whereby FliC-D0C is first trapped by the hydrophobic pocket of NAIP5, then locked in the binding site by ID (insertion domain) and C-terminal tail of NAIP5. The FliC-D0N domain further inserts into ID to stabilize the complex. According to this mechanism, FliC triggers the conformational change of NAIP5 by bringing multiple flexible domains together.
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Affiliation(s)
- Bhaskar Paidimuddala
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
| | - Jianhao Cao
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
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17
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Devant P, Dong Y, Mintseris J, Ma W, Gygi SP, Wu H, Kagan JC. Structural insights into cytokine cleavage by inflammatory caspase-4. Nature 2023; 624:451-459. [PMID: 37993712 PMCID: PMC10807405 DOI: 10.1038/s41586-023-06751-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 10/16/2023] [Indexed: 11/24/2023]
Abstract
Inflammatory caspases are key enzymes in mammalian innate immunity that control the processing and release of interleukin-1 (IL-1)-family cytokines1,2. Despite the biological importance, the structural basis for inflammatory caspase-mediated cytokine processing has remained unclear. To date, catalytic cleavage of IL-1-family members, including pro-IL-1β and pro-IL-18, has been attributed primarily to caspase-1 activities within canonical inflammasomes3. Here we demonstrate that the lipopolysaccharide receptor caspase-4 from humans and other mammalian species (except rodents) can cleave pro-IL-18 with an efficiency similar to pro-IL-1β and pro-IL-18 cleavage by the prototypical IL-1-converting enzyme caspase-1. This ability of caspase-4 to cleave pro-IL-18, combined with its previously defined ability to cleave and activate the lytic pore-forming protein gasdermin D (GSDMD)4,5, enables human cells to bypass the need for canonical inflammasomes and caspase-1 for IL-18 release. The structure of the caspase-4-pro-IL-18 complex determined using cryogenic electron microscopy reveals that pro-lL-18 interacts with caspase-4 through two distinct interfaces: a protease exosite and an interface at the caspase-4 active site involving residues in the pro-domain of pro-IL-18, including the tetrapeptide caspase-recognition sequence6. The mechanisms revealed for cytokine substrate capture and cleavage differ from those observed for the caspase substrate GSDMD7,8. These findings provide a structural framework for the discussion of caspase activities in health and disease.
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Affiliation(s)
- Pascal Devant
- Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Ying Dong
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Julian Mintseris
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Weiyi Ma
- Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.
| | - Jonathan C Kagan
- Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA.
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18
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Alphonse N, Odendall C. Animal models of shigellosis: a historical overview. Curr Opin Immunol 2023; 85:102399. [PMID: 37952487 DOI: 10.1016/j.coi.2023.102399] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/31/2023] [Accepted: 10/31/2023] [Indexed: 11/14/2023]
Abstract
Shigella spp. are major causative agents of bacillary dysentery, a severe enteric disease characterized by destruction and inflammation of the colonic epithelium accompanied by acute diarrhea, fever, and abdominal pain. Although antibiotics have traditionally been effective, the prevalence of multidrug-resistant strains is increasing, stressing the urgent need for a vaccine. The human-specific nature of shigellosis and the absence of a dependable animal model have posed significant obstacles in understanding Shigella pathogenesis and the host immune response, both of which are crucial for the development of an effective vaccine. Efforts have been made over time to develop a physiological model that mimics the pathological features of the human disease with limited success until the recent development of genetically modified mouse models. In this review, we provide an overview of Shigella pathogenesis and chronicle the historical development of various shigellosis models, emphasizing their strengths and weaknesses.
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Affiliation(s)
- Noémie Alphonse
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK; Immunoregulation Laboratory, Francis Crick Institute, London, UK.
| | - Charlotte Odendall
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK.
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19
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Harrison D, Billinton A, Bock MG, Doedens JR, Gabel CA, Holloway MK, Porter RA, Reader V, Scanlon J, Schooley K, Watt AP. Discovery of Clinical Candidate NT-0796, a Brain-Penetrant and Highly Potent NLRP3 Inflammasome Inhibitor for Neuroinflammatory Disorders. J Med Chem 2023; 66:14897-14911. [PMID: 37874905 DOI: 10.1021/acs.jmedchem.3c01398] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
The NLRP3 inflammasome is a component of the innate immune system involved in the production of proinflammatory cytokines. Neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and amyotrophic lateral sclerosis, have been shown to have a component driven by NLRP3 inflammasome activation. Diseases such as these with large unmet medical needs have resulted in an interest in inhibiting the NLRP3 inflammasome as a potential pharmacological treatment, but to date, no marketed drugs specifically targeting NLRP3 have been approved. Furthermore, the requirement for CNS-penetrant molecules adds additional complexity to the search for NLRP3 inflammasome inhibitors suitable for clinical investigation of neuroinflammatory disorders. We designed a series of ester-substituted carbamate compounds as selective NLRP3 inflammasome inhibitors, leading to NT-0796, an isopropyl ester that undergoes intracellular conversion to NDT-19795, the carboxylic acid active species. NT-0796 was shown to be a potent and selective NLRP3 inflammasome inhibitor with demonstrated in vivo brain penetration.
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Affiliation(s)
- David Harrison
- NodThera Ltd., Suite 8, The Mansion, Chesterford Research Park, Little Chesterford, Saffron Walden CB10 1XL, Essex, U.K
| | - Andy Billinton
- NodThera Ltd., Suite 8, The Mansion, Chesterford Research Park, Little Chesterford, Saffron Walden CB10 1XL, Essex, U.K
| | - Mark G Bock
- NodThera Inc., P.O. Box 156, Suite 1702, 265 Franklin Street, Boston, Massachusetts 02110, United States
| | - John R Doedens
- NodThera Inc., 454 N 34th Street, Seattle, Washington 98103, United States
| | | | | | - Roderick A Porter
- Rod Porter Consultancy, 89 Back Street, Ashwell, Baldock SG7 5PG, Hertfordshire, U.K
| | - Valérie Reader
- NodThera Ltd., Suite 8, The Mansion, Chesterford Research Park, Little Chesterford, Saffron Walden CB10 1XL, Essex, U.K
| | - Jane Scanlon
- NodThera Ltd., Suite 8, The Mansion, Chesterford Research Park, Little Chesterford, Saffron Walden CB10 1XL, Essex, U.K
| | - Kenneth Schooley
- NodThera Inc., 454 N 34th Street, Seattle, Washington 98103, United States
| | - Alan P Watt
- NodThera Ltd., Suite 8, The Mansion, Chesterford Research Park, Little Chesterford, Saffron Walden CB10 1XL, Essex, U.K
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20
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Zhang J, Brodsky IE, Shin S. Yersinia deploys type III-secreted effectors to evade caspase-4 inflammasome activation in human cells. mBio 2023; 14:e0131023. [PMID: 37615436 PMCID: PMC10653943 DOI: 10.1128/mbio.01310-23] [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: 06/15/2023] [Accepted: 07/06/2023] [Indexed: 08/25/2023] Open
Abstract
IMPORTANCE Yersinia are responsible for significant disease burden in humans, ranging from recurrent disease outbreaks (yersiniosis) to pandemics (Yersinia pestis plague). Together with rising antibiotic resistance rates, there is a critical need to better understand Yersinia pathogenesis and host immune mechanisms, as this information will aid in developing improved immunomodulatory therapeutics. Inflammasome responses in human cells are less studied relative to murine models of infection, though recent studies have uncovered key differences in inflammasome responses between mice and humans. Here, we dissect human intestinal epithelial cell and macrophage inflammasome responses to Yersinia pseudotuberculosis. Our findings provide insight into species- and cell type-specific differences in inflammasome responses to Yersinia.
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Affiliation(s)
- Jenna Zhang
- Department of Microbiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Igor E. Brodsky
- Department of Pathobiology, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
| | - Sunny Shin
- Department of Microbiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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21
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Kroken AR, Klein KA, Mitchell PS, Nieto V, Jedel EJ, Evans DJ, Fleiszig SMJ. Intracellular replication of Pseudomonas aeruginosa in epithelial cells requires suppression of the caspase-4 inflammasome. mSphere 2023; 8:e0035123. [PMID: 37589460 PMCID: PMC10597407 DOI: 10.1128/msphere.00351-23] [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: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 08/18/2023] Open
Abstract
Pathogenesis of Pseudomonas aeruginosa infections can include bacterial survival inside epithelial cells. Previously, we showed that this involves multiple roles played by the type three secretion system (T3SS), and specifically the effector ExoS. This includes ExoS-dependent inhibition of a lytic host cell response that subsequently enables intracellular replication. Here, we studied the underlying cell death response to intracellular P. aeruginosa, comparing wild-type to T3SS mutants varying in capacity to induce cell death and that localize to different intracellular compartments. Results showed that corneal epithelial cell death induced by intracellular P. aeruginosa lacking the T3SS, which remains in vacuoles, correlated with the activation of nuclear factor-κB as measured by p65 relocalization and tumor necrosis factor alpha transcription and secretion. Deletion of caspase-4 through CRISPR-Cas9 mutagenesis delayed cell death caused by these intracellular T3SS mutants. Caspase-4 deletion also countered more rapid cell death caused by T3SS effector-null mutants still expressing the T3SS apparatus that traffic to the host cell cytoplasm, and in doing so rescued intracellular replication normally dependent on ExoS. While HeLa cells lacked a lytic death response to T3SS mutants, it was found to be enabled by interferon gamma treatment. Together, these results show that epithelial cells can activate the noncanonical inflammasome pathway to limit proliferation of intracellular P. aeruginosa, not fully dependent on bacterially driven vacuole escape. Since ExoS inhibits the lytic response, the data implicate targeting of caspase-4, an intracellular pattern recognition receptor, as another contributor to the role of ExoS in the intracellular lifestyle of P. aeruginosa. IMPORTANCE Pseudomonas aeruginosa can exhibit an intracellular lifestyle within epithelial cells in vivo and in vitro. The type three secretion system (T3SS) effector ExoS contributes via multiple mechanisms, including extending the life of invaded host cells. Here, we aimed to understand the underlying cell death inhibited by ExoS when P. aeruginosa is intracellular. Results showed that intracellular P. aeruginosa lacking T3SS effectors could elicit rapid cell lysis via the noncanonical inflammasome pathway. Caspase-4 contributed to cell lysis even when the intracellular bacteria lacked the entire T33S and were consequently unable to escape vacuoles, representing a naturally occurring subpopulation during wild-type infection. Together, the data show the caspase-4 inflammasome as an epithelial cell defense against intracellular P. aeruginosa, and implicate its targeting as another mechanism by which ExoS preserves the host cell replicative niche.
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Affiliation(s)
- Abby R. Kroken
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, USA
- Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley, California, USA
| | - Keith A. Klein
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, USA
| | - Patrick S. Mitchell
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Vincent Nieto
- Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley, California, USA
| | - Eric J. Jedel
- Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley, California, USA
| | - David J. Evans
- Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley, California, USA
- College of Pharmacy, Touro University California, Vallejo, California, USA
| | - Suzanne M. J. Fleiszig
- Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley, California, USA
- Graduate Groups in Vision Sciences, Microbiology, and Infectious Diseases & Immunity, University of California, Berkeley, California, USA
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22
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Stockton JL, Khakhum N, Stevenson HL, Torres AG. Burkholderia pseudomallei BicA protein promotes pathogenicity in macrophages by regulating invasion, intracellular survival, and virulence. mSphere 2023; 8:e0037823. [PMID: 37768049 PMCID: PMC10597401 DOI: 10.1128/msphere.00378-23] [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: 07/10/2023] [Accepted: 08/08/2023] [Indexed: 09/29/2023] Open
Abstract
Burkholderia pseudomallei (Bpm) is the causative agent of melioidosis disease. Bpm is a facultative intracellular pathogen with a complex life cycle inside host cells. Pathogenic success depends on a variety of virulence factors with one of the most critical being the type 6 secretion system (T6SS). Bpm uses the T6SS to move into neighboring cells, resulting in multinucleated giant cell (MNGC) formation, a strategy used to disseminate from cell to cell. Our prior study using a dual RNA-seq analysis to dissect T6SS-mediated virulence on intestinal epithelial cells identified BicA as a factor upregulated in a T6SS mutant. BicA regulates both type 3 secretion system (T3SS) and T6SSs; however, the extent of its involvement during disease progression is unclear. To fully dissect the role of BicA during systemic infection, we used two macrophage cell lines paired with a pulmonary in vivo challenge murine model. We found that ΔbicA has a distinct intracellular replication defect in both immortalized and primary macrophages, which begins as early as 1 h post-infection. This intracellular defect is linked with the lack of cell-to-cell dissemination and MNGC formation as well as a defect in T3SS expression. The in vitro phenotype translated in vivo as ΔbicA was attenuated in a pulmonary model of infection, demonstrating a distinct macrophage activation profile and a lack of pathological features present in the wild type. Overall, these results highlight the role of BicA in regulating intracellular virulence and demonstrate that specific regulation of secretion systems has a significant effect on host response and Bpm pathogenesis. IMPORTANCE Melioidosis is an understudied tropical disease that still results in ~50% fatalities in infected patients. It is caused by the Gram-negative bacillus Burkholderia pseudomallei (Bpm). Bpm is an intracellular pathogen that disseminates from the infected cell to target organs, causing disseminated disease. The regulation of secretion systems involved in entry and cell-to-cell spread is poorly understood. In this work, we characterize the role of BicA as a regulator of secretion systems during infection of macrophages in vitro and in vivo. Understanding how these virulence factors are controlled will help us determine their influence on the host cells and define the macrophage responses associated with bacterial clearance.
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Affiliation(s)
- Jacob L. Stockton
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Nittaya Khakhum
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Heather L. Stevenson
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Alfredo G. Torres
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, USA
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA
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23
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Pandeya A, Zhang Y, Cui J, Yang L, Li J, Zhang G, Wu C, Li Z, Wei Y. Inflammasome activation and pyroptosis mediate coagulopathy and inflammation in Salmonella systemic infection. Microbiol Res 2023; 275:127460. [PMID: 37467711 PMCID: PMC10693354 DOI: 10.1016/j.micres.2023.127460] [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: 05/27/2023] [Revised: 07/09/2023] [Accepted: 07/12/2023] [Indexed: 07/21/2023]
Abstract
Inflammasome activation is a critical defense mechanism against bacterial infection. Previous studies suggest that inflammasome activation protects against Salmonella oral infection. Here we find inflammasome activation plays a critical role in the pathogenesis of Salmonella systemic infection. We show that in a systemic infection model by i.p. injection of Salmonella, deficiency of caspase-1 or gasdermin-D prolonged survival time, reduced plasma concentrations of the proinflammatory cytokines IL-1β, IL-6 and TNFα. These deficiencies also protected against coagulopathy during Salmonella infection as evidenced by diminished prolongation of prothrombin time and increase in plasma thrombin-antithrombin complex concentrations in the caspase-1 or gasdermin-D deficient mice. Activation of the NAIP/NLRC4 inflammasome by flagellin and/or the components of the SPI1 type 3 secretion system played a critical role in Salmonella-induced coagulopathy. In the absence of flagellin and SPI1, the Salmonella mutant strain still triggered coagulopathy through the caspase-11/NLRP3 pathway. Our results reveal a previously undisclosed role of the inflammasomes and pyroptosis in the pathogenesis of Salmonella systemic infection.
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Affiliation(s)
- Ankit Pandeya
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, USA; Department of Chemistry, University of Kentucky, Lexington, KY, USA
| | - Yan Zhang
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, USA
| | - Jian Cui
- Saha Cardiovascular Research Center, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Ling Yang
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, USA
| | - Jeffery Li
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, USA
| | - Guoying Zhang
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, USA
| | - Congqing Wu
- Saha Cardiovascular Research Center, College of Medicine, University of Kentucky, Lexington, KY, USA; Department of Surgery, College of Medicine, University of Kentucky, Lexington, KY, USA; Department of Microbiology, Immunology, and Molecular Genetics, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Zhenyu Li
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, USA.
| | - Yinan Wei
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, USA.
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24
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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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25
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Abstract
The immune system of multicellular organisms protects them from harmful microbes. To establish an infection in the face of host immune responses, pathogens must evolve specific strategies to target immune defense mechanisms. One such defense is the formation of intracellular protein complexes, termed inflammasomes, that are triggered by the detection of microbial components and the disruption of homeostatic processes that occur during bacterial infection. Formation of active inflammasomes initiates programmed cell death pathways via activation of inflammatory caspases and cleavage of target proteins. Inflammasome-activated cell death pathways such as pyroptosis lead to proinflammatory responses that protect the host. Bacterial infection has the capacity to influence inflammasomes in two distinct ways: activation and perturbation. In this review, we discuss how bacterial activities influence inflammasomes, and we discuss the consequences of inflammasome activation or evasion for both the host and pathogen.
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Affiliation(s)
- Beatrice I Herrmann
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; ,
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - James P Grayczyk
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; ,
- Current affiliation: Oncology Discovery, Abbvie, Inc., Chicago, Illinois, USA;
| | - Igor E Brodsky
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; ,
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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26
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López-Yglesias AH, Lu CC, Lai MA, Quarles EK, Zhao X, Hajjar AM, Smith KD. FlgM is required to evade NLRC4-mediated host protection against flagellated Salmonella. Infect Immun 2023; 91:e0025523. [PMID: 37638725 PMCID: PMC10501211 DOI: 10.1128/iai.00255-23] [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: 07/05/2023] [Accepted: 07/07/2023] [Indexed: 08/29/2023] Open
Abstract
Salmonella enterica serovar Typhimurium is a leading cause of gastroenteritis worldwide and a deadly pathogen in children, immunocompromised patients, and the elderly. Salmonella induces innate immune responses through the NLRC4 inflammasome, which has been demonstrated to have distinct roles during systemic and mucosal detections of flagellin and non-flagellin molecules. We hypothesized that NLRC4 recognition of Salmonella flagellin is the dominant protective pathway during infection. To test this hypothesis, we used wild-type, flagellin-deficient, and flagellin-overproducing Salmonella to establish the role of flagellin in mediating NLRC4-dependent host resistance during systemic and mucosal infections in mice. We observed that during the systemic phase of infection, Salmonella efficiently evades NLRC4-mediated innate immunity. During mucosal Salmonella infection, flagellin recognition by the NLRC4 inflammasome pathway is the dominant mediator of protective innate immunity. Deletion of flgM results in constitutive expression of flagellin and severely limits systemic and mucosal Salmonella infections in an NLRC4 inflammasome-dependent manner. These data establish that recognition of Salmonella's flagellin by the NLRC4 inflammasome during mucosal infection is the dominant innate protective pathway for host resistance against the enteric pathogen and that FlgM-mediated evasion of the NLRC4 inflammasome enhances virulence and intestinal tissue destruction.
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Affiliation(s)
| | - Chun-Chi Lu
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Marvin A. Lai
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Ellen K. Quarles
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Xiaodan Zhao
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Adeline M. Hajjar
- Department of Comparative Medicine, University of Washington, Seattle, Washington, USA
| | - Kelly D. Smith
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
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27
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Chai Q, Lei Z, Liu CH. Pyroptosis modulation by bacterial effector proteins. Semin Immunol 2023; 69:101804. [PMID: 37406548 DOI: 10.1016/j.smim.2023.101804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 06/28/2023] [Accepted: 06/29/2023] [Indexed: 07/07/2023]
Abstract
Pyroptosis is a proinflammatory form of programmed cell death featured with membrane pore formation that causes cellular swelling and allows the release of intracellular inflammatory mediators. This cell death process is elicited by the activation of the pore-forming proteins named gasdermins, and is intricately orchestrated by diverse regulatory factors in mammalian hosts to exert a prompt immune response against infections. However, growing evidence suggests that bacterial pathogens have evolved to regulate host pyroptosis for evading immune clearance and establishing progressive infection. In this review, we highlight current understandings of the functional role and regulatory network of pyroptosis in host antibacterial immunity. Thereafter, we further discuss the latest advances elucidating the mechanisms by which bacterial pathogens modulate pyroptosis through adopting their effector proteins to drive infections. A better understanding of regulatory mechanisms underlying pyroptosis at the interface of host-bacterial interactions will shed new light on the pathogenesis of infectious diseases and contribute to the development of promising therapeutic strategies against bacterial pathogens.
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Affiliation(s)
- Qiyao Chai
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Zehui Lei
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid Medical School, University of Chinese Academy of Sciences, Beijing 101408, China
| | - Cui Hua Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid Medical School, University of Chinese Academy of Sciences, Beijing 101408, China.
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28
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Turton K, Parks HJ, Zarodkiewicz P, Hamad MA, Dwane R, Parau G, Ingram RJ, Coll RC, Bryant CE, Valvano MA. The Achromobacter type 3 secretion system drives pyroptosis and immunopathology via independent activation of NLRC4 and NLRP3 inflammasomes. Cell Rep 2023; 42:113012. [PMID: 37598340 PMCID: PMC7614980 DOI: 10.1016/j.celrep.2023.113012] [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: 02/07/2023] [Revised: 07/19/2023] [Accepted: 08/04/2023] [Indexed: 08/22/2023] Open
Abstract
How the opportunistic Gram-negative pathogens of the genus Achromobacter interact with the innate immune system is poorly understood. Using three Achromobacter clinical isolates from two species, we show that the type 3 secretion system (T3SS) is required to induce cell death in human macrophages by inflammasome-dependent pyroptosis. Macrophages deficient in the inflammasome sensors NLRC4 or NLRP3 undergo pyroptosis upon bacterial internalization, but those deficient in both NLRC4 and NLRP3 do not, suggesting either sensor mediates pyroptosis in a T3SS-dependent manner. Detailed analysis of the intracellular trafficking of one isolate indicates that the intracellular bacteria reside in a late phagolysosome. Using an intranasal mouse infection model, we observe that Achromobacter damages lung structure and causes severe illness, contingent on a functional T3SS. Together, we demonstrate that Achromobacter species can survive phagocytosis by promoting macrophage cell death and inflammation by redundant mechanisms of pyroptosis induction in a T3SS-dependent manner.
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Affiliation(s)
- Keren Turton
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Hannah J Parks
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Paulina Zarodkiewicz
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Mohamad A Hamad
- Department of Medical Laboratory Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Rachel Dwane
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Georgiana Parau
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Rebecca J Ingram
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Rebecca C Coll
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Clare E Bryant
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK; Department of Medicine, Addenbrooke's Hospital, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Miguel A Valvano
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK.
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29
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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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30
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Zhang J, Brodsky IE, Shin S. Yersinia Type III-Secreted Effectors Evade the Caspase-4 Inflammasome in Human Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.24.525473. [PMID: 36747770 PMCID: PMC9900831 DOI: 10.1101/2023.01.24.525473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Yersinia are gram-negative zoonotic bacteria that use a type III secretion system (T3SS) to inject Yersinia outer proteins (Yops) into the host cytosol to subvert essential components of innate immune signaling. However, Yersinia virulence activities can elicit activation of inflammasomes, which lead to inflammatory cell death and cytokine release to contain infection. Yersinia activation and evasion of inflammasomes have been characterized in murine macrophages but remain poorly defined in human cells, particularly intestinal epithelial cells (IECs), a primary site of intestinal Yersinia infection. In contrast to murine macrophages, we find that in both human IECs and macrophages, Yersinia pseudotuberculosis T3SS effectors enable evasion of the caspase-4 inflammasome, which senses cytosolic lipopolysaccharide (LPS). The antiphagocytic YopE and YopH, as well as the translocation regulator YopK, were collectively responsible for evading inflammasome activation, in part by inhibiting Yersinia internalization mediated by YadA and β1-integrin signaling. These data provide insight into the mechanisms of Yersinia-mediated inflammasome activation and evasion in human cells, and reveal species-specific differences underlying regulation of inflammasome responses to Yersinia .
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Affiliation(s)
- Jenna Zhang
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
| | - Igor E. Brodsky
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania 19104
| | - Sunny Shin
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
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31
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Paidimuddala B, Cao J, Zhang L. Structural basis for flagellin induced NAIP5 activation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.13.544801. [PMID: 37398004 PMCID: PMC10312664 DOI: 10.1101/2023.06.13.544801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
The NAIP/NLRC4 inflammasome is activated when NAIP binds to a gram-negative bacterial ligand. Initially, NAIP exists in an inactive state with a wide-open conformation. Upon ligand binding, the winged helix domain (WHD) of NAIP is activated and forms steric clash with NLRC4 to open it up. However, how ligand binding induces the conformational change of NAIP is less clear. To understand this process, we investigated the dynamics of the ligand binding region of inactive NAIP5 and solved the cryo-EM structure of NAIP5 in complex with its specific ligand, FliC from flagellin, at 2.93 Å resolution. The structure revealed a "trap and lock" mechanism in FliC recognition, whereby FliC-D0C is first trapped by the hydrophobic pocket of NAIP5, then locked in the binding site by the insertion domain (ID) and C-terminal tail (CTT) of NAIP5. The FliC-D0N domain further inserts into the loop of ID to stabilize the complex. According to this mechanism, FliC activates NAIP5 by bringing multiple flexible domains together, particularly the ID, HD2, and LRR domains, to form the active conformation and support the WHD loop in triggering NLRC4 activation.
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Affiliation(s)
- Bhaskar Paidimuddala
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
| | - Jianhao Cao
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
| | - Liman Zhang
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
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32
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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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33
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Barnett KC, Li S, Liang K, Ting JPY. A 360° view of the inflammasome: Mechanisms of activation, cell death, and diseases. Cell 2023; 186:2288-2312. [PMID: 37236155 PMCID: PMC10228754 DOI: 10.1016/j.cell.2023.04.025] [Citation(s) in RCA: 95] [Impact Index Per Article: 95.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 04/06/2023] [Accepted: 04/17/2023] [Indexed: 05/28/2023]
Abstract
Inflammasomes are critical sentinels of the innate immune system that respond to threats to the host through recognition of distinct molecules, known as pathogen- or damage-associated molecular patterns (PAMPs/DAMPs), or disruptions of cellular homeostasis, referred to as homeostasis-altering molecular processes (HAMPs) or effector-triggered immunity (ETI). Several distinct proteins nucleate inflammasomes, including NLRP1, CARD8, NLRP3, NLRP6, NLRC4/NAIP, AIM2, pyrin, and caspases-4/-5/-11. This diverse array of sensors strengthens the inflammasome response through redundancy and plasticity. Here, we present an overview of these pathways, outlining the mechanisms of inflammasome formation, subcellular regulation, and pyroptosis, and discuss the wide-reaching effects of inflammasomes in human disease.
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Affiliation(s)
- Katherine C Barnett
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Sirui Li
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kaixin Liang
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Oral and Craniofacial Biomedicine Program, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jenny P-Y Ting
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Oral and Craniofacial Biomedicine Program, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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34
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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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35
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Gao Y, Yang Y, Wei J, Yue J, Wang Y, Zhang Q, Jin M, Wang R, Yang X, Zhang J, Liu X, Liu L, Zhang Y, Yang R. LNCGM1082-mediated NLRC4 activation drives resistance to bacterial infection. Cell Mol Immunol 2023; 20:475-488. [PMID: 36941318 PMCID: PMC10203293 DOI: 10.1038/s41423-023-00995-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 02/23/2023] [Indexed: 03/23/2023] Open
Abstract
The activation of NLRC4 is a major host response against intracellular bacteria infection. However, NLRC4 activation after a host senses diverse stimuli is difficult to understand. Here, we found that the lncRNA LNCGM1082 plays a critical role in the activation of NLRC4. LNCGM1082 in macrophages affects the maturation of interleukin (IL)-1β and pyroptotic cell death only after exposure to an NLRC4 ligand. Similar to NLRC4-/- mice, LNCGM1082-/- mice were highly sensitive to Salmonella Typhimurium (S. T) infection. LNCGM1082 deficiency in mouse or human macrophages inhibited IL-1β maturation and pyroptosis. Mechanistically, LNCGM1082 induced the binding of PKCδ with NLRC4 in both mice and humans. In contrast, NLRC4 did not bind PKCδ in LNCGM1082-/- macrophages. The activity of the lncRNA LNCGM1082 induced by S. T may be mediated through TLR5 in the macrophages of both mice and humans. In summary, our data indicate that TLR5-mediated LNCGM1082 activity can promote the binding of PKCδ with NLRC4 to activate NLRC4 and induce resistance to bacterial infection.
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Affiliation(s)
- Yunhuan Gao
- Department of Immunology, Nankai University School of Medicine and Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China
| | - Yazheng Yang
- Department of Immunology, Nankai University School of Medicine and Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China
| | - Jianmei Wei
- Department of Immunology, Nankai University School of Medicine and Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China
| | - Jianmei Yue
- Department of Immunology, Nankai University School of Medicine and Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China
| | - Ya Wang
- Department of Immunology, Nankai University School of Medicine and Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China
| | - Qianjing Zhang
- Department of Immunology, Nankai University School of Medicine and Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China
| | - Mengli Jin
- Department of Immunology, Nankai University School of Medicine and Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China
| | - Rong Wang
- Department of Immunology, Nankai University School of Medicine and Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China
| | - Xiaorong Yang
- Department of Immunology, Nankai University School of Medicine and Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China
| | - Junqi Zhang
- College of Life Science, Nankai University, Tianjin, 300121, China
| | - Xinqi Liu
- College of Life Science, Nankai University, Tianjin, 300121, China
| | - Lin Liu
- China National Center for Bioinformation & Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Yuan Zhang
- Department of Immunology, Nankai University School of Medicine and Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China
| | - Rongcun Yang
- Department of Immunology, Nankai University School of Medicine and Translational Medicine Institute, Affiliated Tianjin Union Medical Center of Nankai University, Nankai University, Tianjin, 300071, China.
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China.
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Kroken AR, Klein KA, Mitchell PS, Nieto V, Jedel EJ, Evans DJ, Fleiszig SMJ. Intracellular replication of Pseudomonas aeruginosa in epithelial cells requires suppression of the caspase-4 inflammasome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.13.528260. [PMID: 36824932 PMCID: PMC9948977 DOI: 10.1101/2023.02.13.528260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Pathogenesis of Pseudomonas aeruginosa infections can include bacterial survival inside epithelial cells. Previously, we showed this involves multiple roles played by the type three-secretion system (T3SS), and specifically the effector ExoS. This includes ExoS-dependent inhibition of a lytic host cell response that subsequently enables intracellular replication. Here, we studied the underlying cell death response to intracellular P. aeruginosa, comparing wild-type to T3SS mutants varying in capacity to induce cell death and that localize to different intracellular compartments. Results showed that corneal epithelial cell death induced by intracellular P. aeruginosa lacking the T3SS, which remains in vacuoles, correlated with activation of NF-κB as measured by p65 relocalization and TNFα transcription and secretion. Deletion of caspase-4 through CRISPR-Cas9 mutagenesis delayed cell death caused by these intracellular T3SS mutants. Caspase-4 deletion also countered more rapid cell death caused by T3SS effector-null mutants still expressing the TSSS apparatus that traffic to the host cell cytoplasm, and in doing so rescued intracellular replication normally dependent on ExoS. While HeLa cells lacked a lytic death response to T3SS mutants, it was found to be enabled by interferon gamma treatment. Together, these results show that epithelial cells can activate the noncanonical inflammasome pathway to limit proliferation of intracellular P. aeruginosa, not fully dependent on bacterially-driven vacuole escape. Since ExoS inhibits the lytic response, the data implicate targeting of caspase-4, an intracellular pattern recognition receptor, as another contributor to the role of ExoS in the intracellular lifestyle of P. aeruginosa.
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Affiliation(s)
- Abby R Kroken
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL USA
- Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley, CA USA
| | - Keith A Klein
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL USA
| | | | - Vincent Nieto
- Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley, CA USA
| | - Eric J Jedel
- Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley, CA USA
| | - David J Evans
- Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley, CA USA
- College of Pharmacy, Touro University California, Vallejo, CA USA
| | - Suzanne M J Fleiszig
- Herbert Wertheim School of Optometry & Vision Science, University of California, Berkeley, CA USA
- Graduate Groups in Vision Sciences, Microbiology, and Infectious Diseases & Immunity, University of California, Berkeley, CA USA
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Paidimuddala B, Cao J, Nash G, Xie Q, Wu H, Zhang L. Mechanism of NAIP-NLRC4 inflammasome activation revealed by cryo-EM structure of unliganded NAIP5. Nat Struct Mol Biol 2023; 30:159-166. [PMID: 36604500 PMCID: PMC10576962 DOI: 10.1038/s41594-022-00889-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 11/03/2022] [Indexed: 01/07/2023]
Abstract
The nucleotide-binding domain (NBD), leucine rich repeat (LRR) domain containing protein family (NLR family) apoptosis inhibitory proteins (NAIPs) are cytosolic receptors that play critical roles in the host defense against bacterial infection. NAIPs interact with conserved bacterial ligands and activate the NLR family caspase recruitment domain containing protein 4 (NLRC4) to initiate the NAIP-NLRC4 inflammasome pathway. Here we found the process of NAIP activation is completely different from NLRC4. Our cryo-EM structure of unliganded mouse NAIP5 adopts an unprecedented wide-open conformation, with the nucleating surface fully exposed and accessible to recruit inactive NLRC4. Upon ligand binding, the winged helix domain (WHD) of NAIP5 undergoes roughly 20° rotation to form a steric clash with the inactive NLRC4, which triggers the conformational change of NLRC4 from inactive to active state. We also show the rotation of WHD places the 17-18 loop at a position that directly bind the active NLRC4 and stabilize the NAIP5-NLRC4 complex. Overall, these data provide structural mechanisms of inactive NAIP5, the process of NAIP5 activation and NAIP-dependent NLRC4 activation.
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Affiliation(s)
- Bhaskar Paidimuddala
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University (OHSU), Portland, OR, USA
| | - Jianhao Cao
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University (OHSU), Portland, OR, USA
| | - Grady Nash
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University (OHSU), Portland, OR, USA
| | - Qing Xie
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University (OHSU), Portland, OR, USA
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Liman Zhang
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University (OHSU), Portland, OR, USA.
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38
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Chang MX. Emerging mechanisms and functions of inflammasome complexes in teleost fish. Front Immunol 2023; 14:1065181. [PMID: 36875130 PMCID: PMC9978379 DOI: 10.3389/fimmu.2023.1065181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 02/06/2023] [Indexed: 02/18/2023] Open
Abstract
Inflammasomes are multiprotein complexes, which are assembled in response to a diverse range of exogenous pathogens and endogenous danger signals, leading to produce pro-inflammatory cytokines and induce pyroptotic cell death. Inflammasome components have been identified in teleost fish. Previous reviews have highlighted the conservation of inflammasome components in evolution, inflammasome function in zebrafish infectious and non-infectious models, and the mechanism that induce pyroptosis in fish. The activation of inflammasome involves the canonical and noncanonical pathways, which can play critical roles in the control of various inflammatory and metabolic diseases. The canonical inflammasomes activate caspase-1, and their signaling is initiated by cytosolic pattern recognition receptors. However the noncanonical inflammasomes activate inflammatory caspase upon sensing of cytosolic lipopolysaccharide from Gram-negative bacteria. In this review, we summarize the mechanisms of activation of canonical and noncanonical inflammasomes in teleost fish, with a particular focus on inflammasome complexes in response to bacterial infection. Furthermore, the functions of inflammasome-associated effectors, specific regulatory mechanisms of teleost inflammasomes and functional roles of inflammasomes in innate immune responses are also reviewed. The knowledge of inflammasome activation and pathogen clearance in teleost fish will shed new light on new molecular targets for treatment of inflammatory and infectious diseases.
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Affiliation(s)
- Ming Xian Chang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of InSciences, Wuhan, China.,College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China.,Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
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39
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Scott WP, Rauch I. Inducing Pyroptosis with FlaTox, RodTox, or NeedleTox. Methods Mol Biol 2023; 2641:27-36. [PMID: 37074639 DOI: 10.1007/978-1-0716-3040-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Targeted activation of the NAIP-NLRC4 inflammasome has proven very useful in the study of pyroptosis. FlaTox and derivative LFn-NAIP-ligand cytosolic delivery systems offer a unique opportunity to interrogate both ligand recognition and downstream effects of the NAIP-NLRC4 inflammasome pathway. Here we describe how to stimulate the NAIP-NLRC4 inflammasome in vitro and in vivo. We describe experimental setup and specific considerations for treatment of macrophages in vitro and in vivo injections using a murine model of systemic inflammasome activation. The in vitro readouts of inflammasome activation propidium iodide uptake and lactate dehydrogenase (LDH) release as well as the in vivo readouts of hematocrit and body temperature measurement are described.
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Affiliation(s)
- William P Scott
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, USA
| | - Isabella Rauch
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, USA.
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40
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Paerewijck O, Lamkanfi M. The human inflammasomes. Mol Aspects Med 2022; 88:101100. [PMID: 35696786 DOI: 10.1016/j.mam.2022.101100] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/25/2022] [Accepted: 06/01/2022] [Indexed: 12/14/2022]
Abstract
Two decades of inflammasome research has led to a vast body of knowledge on the complex regulatory mechanisms and pathological roles of canonical and non-canonical inflammasome activation in a plethora of research models of primarily rodent origin. More recently, the field has made notable progress in characterizing human-specific inflammasomes and their regulation mechanisms, including an expansion of inflammasome biology to adaptive immune cells. These exciting developments in basic research have been accompanied by potentially transformative results from large clinical trials and translational efforts to develop inflammasome-targeted small molecule inhibitors for therapeutic use. Here, we will discuss recent findings in the field with a specific emphasis on activation mechanisms of human inflammasomes and their potential role in auto-inflammatory, metabolic and neoplastic diseases.
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Affiliation(s)
- Oonagh Paerewijck
- Laboratory of Medical Immunology, Department of Internal Medicine and Paediatrics, Ghent University, Ghent, B-9000, Belgium
| | - Mohamed Lamkanfi
- Laboratory of Medical Immunology, Department of Internal Medicine and Paediatrics, Ghent University, Ghent, B-9000, Belgium.
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Illig D, Kotlarz D. Dysregulated inflammasome activity in intestinal inflammation - Insights from patients with very early onset IBD. Front Immunol 2022; 13:1027289. [PMID: 36524121 PMCID: PMC9744759 DOI: 10.3389/fimmu.2022.1027289] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 11/11/2022] [Indexed: 11/30/2022] Open
Abstract
Inflammatory bowel disease (IBD) is a multifactorial disorder triggered by imbalances of the microbiome and immune dysregulations in genetically susceptible individuals. Several mouse and human studies have demonstrated that multimeric inflammasomes are critical regulators of host defense and gut homeostasis by modulating immune responses to pathogen- or damage-associated molecular patterns. In the context of IBD, excessive production of pro-inflammatory Interleukin-1β has been detected in patient-derived intestinal tissues and correlated with the disease severity or failure to respond to anti-tumor necrosis factor therapy. Correspondingly, genome-wide association studies have suggested that single nucleotide polymorphisms in inflammasome components might be associated with risk of IBD development. The relevance of inflammasomes in controlling human intestinal homeostasis has been further exemplified by the discovery of very early onset IBD (VEO-IBD) patients with monogenic defects affecting different molecules in the complex regulatory network of inflammasome activity. This review provides an overview of known causative monogenic entities of VEO-IBD associated with altered inflammasome activity. A better understanding of the molecular mechanisms controlling inflammasomes in monogenic VEO-IBD may open novel therapeutic avenues for rare and common inflammatory diseases.
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Affiliation(s)
- David Illig
- Department of Pediatrics, Dr. von Hauner Children’s Hospital, University Hospital, Ludwig-Maximilians-University (LMU), Munich, Germany
| | - Daniel Kotlarz
- Department of Pediatrics, Dr. von Hauner Children’s Hospital, University Hospital, Ludwig-Maximilians-University (LMU), Munich, Germany,Institute of Translational Genomics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany,*Correspondence: Daniel Kotlarz,
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42
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[NLRC4 plays a regulatory role in F. nucleatum-induced pyroptosis in macrophages]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2022; 42:1560-1565. [PMID: 36329592 PMCID: PMC9637494 DOI: 10.12122/j.issn.1673-4254.2022.10.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVE To explore the mechanism of F.nucleatum-induced pyroptosis in macrophages and the regulatory role of inflammasomes. METHODS Lactate dehydrogenase (LDH) cytotoxicity assay and Hoechst 33342/PI double fluorescence staining were used to analyze cytolysis in F.nucleatum-infected macrophage RAW264.7 cells.The expressions of pyroptosis-related proteins caspase-1, GSDMD and IL-1β were determined using Western blotting.Inflammasome activation in the cells was analyzed by detecting the mRNA expressions of NLRP3, NLRC4, AIM2, and NLRP1 with qRT-PCR.RNA interference technique was used to knock down the key molecules involved in pyroptosis regulation in the macrophages, and the pyroptosis and necrosis rates of the cells following F.nucleatum infection were examined. RESULTS The results of LDH cytotoxicity assay and double-fluorescence staining showed that F.nucleatum infection caused swelling and lytic cell death in RAW264.7 cells.F.nucleatum infection resulted in the activation of caspase-1 and GSDMD and upregulated IL-1β expression in a multiplicity of infection (MOI)-and time-dependent manner (P < 0.05).qRT-PCR revealed significantly increased expression of NLRC4 mRNA in the macrophages after F.nucleatum infection (P < 0.05).NLRC4 silencing by siRNA strongly inhibited the activation of caspase-1/GSDMD pathway and reduced cell death (P < 0.05) and IL-1β expression in F.nucleatum-infected cells. CONCLUSION NLRC4 inflammasome drives caspase-1/GSDMD-mediated pyroptosis and inflammatory signaling in F.nucleatum-infected macrophages, suggesting the potential of NLRC4 inflammasome as a therapeutic target for F.nucleatum infections.
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43
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López‐Haber C, Netting DJ, Hutchins Z, Ma X, Hamilton KE, Mantegazza AR. The phagosomal solute transporter SLC15A4 promotes inflammasome activity via mTORC1 signaling and autophagy restraint in dendritic cells. EMBO J 2022; 41:e111161. [PMID: 36031853 PMCID: PMC9574736 DOI: 10.15252/embj.2022111161] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 07/22/2022] [Accepted: 08/01/2022] [Indexed: 01/18/2023] Open
Abstract
Phagocytosis is the necessary first step to sense foreign microbes or particles and enables activation of innate immune pathways such as inflammasomes. However, the molecular mechanisms underlying how phagosomes modulate inflammasome activity are not fully understood. We show that in murine dendritic cells (DCs), the lysosomal histidine/peptide solute carrier transporter SLC15A4, associated with human inflammatory disorders, is recruited to phagosomes and is required for optimal inflammasome activity after infectious or sterile stimuli. Dextran sodium sulfate-treated SLC15A4-deficient mice exhibit decreased colon inflammation, reduced IL-1β production by intestinal DCs, and increased autophagy. Similarly, SLC15A4-deficient DCs infected with Salmonella typhimurium show reduced caspase-1 cleavage and IL-1β production. This correlates with peripheral NLRC4 inflammasome assembly and increased autophagy. Overexpression of constitutively active mTORC1 rescues decreased IL-1β levels and caspase1 cleavage, and restores perinuclear inflammasome positioning. Our findings support that SLC15A4 couples phagocytosis with inflammasome perinuclear assembly and inhibition of autophagy through phagosomal content sensing. Our data also reveal the previously unappreciated importance of mTORC1 signaling pathways to promote and sustain inflammasome activity.
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Affiliation(s)
- Cynthia López‐Haber
- Department of Pathology and Laboratory MedicineChildren's Hospital of PhiladelphiaPhiladelphiaPAUSA
- Department of Pathology and Laboratory Medicine, Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
- Present address:
Department of Microbiology and Immunology, Sidney Kimmel Medical CollegeThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Daniel J Netting
- Department of Microbiology and Immunology, Sidney Kimmel Medical CollegeThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Zachary Hutchins
- Department of Microbiology and Immunology, Sidney Kimmel Medical CollegeThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Xianghui Ma
- Division of Gastroenterology, Hepatology, and Nutrition, Department of PediatricsChildren's Hospital of PhiladelphiaPhiladelphiaPAUSA
| | - Kathryn E Hamilton
- Division of Gastroenterology, Hepatology, and Nutrition, Department of PediatricsChildren's Hospital of PhiladelphiaPhiladelphiaPAUSA
| | - Adriana R Mantegazza
- Department of Pathology and Laboratory MedicineChildren's Hospital of PhiladelphiaPhiladelphiaPAUSA
- Department of Pathology and Laboratory Medicine, Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
- Present address:
Department of Microbiology and Immunology, Sidney Kimmel Medical CollegeThomas Jefferson UniversityPhiladelphiaPAUSA
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Sun J, Li Y. Pyroptosis and respiratory diseases: A review of current knowledge. Front Immunol 2022; 13:920464. [PMID: 36248872 PMCID: PMC9561627 DOI: 10.3389/fimmu.2022.920464] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Pyroptosis is a relatively newly discovered programmed cell death accompanied by an inflammatory response. In the classical view, pyroptosis is mediated by caspases-1,-4,-5,-11 and executed by GSDMD, however, recently it was demonstrated that caspase-3 and-8 also participate in the process of pyroptosis, by cleaving GSDMD/E and GSDMD respectively. Different from autophagy and apoptosis, many pores are formed on the cell membrane during pyroptosis, which makes the cell membrane lose its integrity, eventually leading to the release of cytokines interleukin(IL)-1β and IL-18. When the body is infected with pathogens or exposed to some stimulations, pyroptosis could play an immune defense role. It is found that pyroptosis exists widely in infectious and inflammatory respiratory diseases such as acute lung injury, bronchial dysplasia, chronic obstructive pulmonary disease, and asthma. Excessive pyroptosis may accompany airway inflammation, tissue injury, and airway damage, and induce an inflammatory reaction, leading to more serious damage and poor prognosis of respiratory diseases. This review summarizes the relationship between pyroptosis and related respiratory diseases.
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45
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Hoang TX, Kim JY. Cell Surface Hsp90- and αMβ2 Integrin-Mediated Uptake of Bacterial Flagellins to Activate Inflammasomes by Human Macrophages. Cells 2022; 11:cells11182878. [PMID: 36139453 PMCID: PMC9496951 DOI: 10.3390/cells11182878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/11/2022] [Accepted: 09/12/2022] [Indexed: 11/16/2022] Open
Abstract
All-trans retinoic acid (ATRA) is an active metabolite of vitamin A, which plays an important role in the immune function. Here, we demonstrated that ATRA induces the heat shock protein (Hsp) 90 complex on the surface of THP-1 macrophages, which facilitates the internalization of exogenous bacterial flagellins to activate the inflammasome response. Mass spectrometric protein identification and co-immunoprecipitation revealed that the Hsp90 homodimer interacts with both Hsp70 and αMβ2 integrin. ATRA-induced complex formation was dependent on the retinoic acid receptor (RAR)/retinoid X receptor (RXR) pathway and intracellular calcium level and was essential for triggering the internalization of bacterial flagellin, which was clathrin dependent. Notably, in this process, αMβ2 integrin was found to act as a carrier to deliver flagellin to the cytosol to activate the inflammasome, leading to caspase-1 activity and secretion of interleukin (IL)-1β. Our study provides new insights into the underlying molecular mechanism by which exogenous bacterial flagellins are delivered into host cells without a bacterial transport system, as well as the mechanism by which vitamin A contributes to enhancing the human macrophage function to detect and respond to bacterial infection.
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Structural mechanisms of inflammasome regulation revealed by cryo-EM studies. Curr Opin Struct Biol 2022; 75:102390. [DOI: 10.1016/j.sbi.2022.102390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/15/2022] [Accepted: 04/22/2022] [Indexed: 11/20/2022]
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Naseer N, Zhang J, Bauer R, Constant DA, Nice TJ, Brodsky IE, Rauch I, Shin S. Salmonella enterica Serovar Typhimurium Induces NAIP/NLRC4- and NLRP3/ASC-Independent, Caspase-4-Dependent Inflammasome Activation in Human Intestinal Epithelial Cells. Infect Immun 2022; 90:e0066321. [PMID: 35678562 PMCID: PMC9302179 DOI: 10.1128/iai.00663-21] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 05/23/2022] [Indexed: 01/09/2023] Open
Abstract
Salmonella enterica serovar Typhimurium is a Gram-negative pathogen that causes diseases ranging from gastroenteritis to systemic infection and sepsis. Salmonella uses type III secretion systems (T3SS) to inject effectors into host cells. While these effectors are necessary for bacterial invasion and intracellular survival, intracellular delivery of T3SS products also enables detection of translocated Salmonella ligands by cytosolic immune sensors. Some of these sensors form multimeric complexes called inflammasomes, which activate caspases that lead to interleukin-1 (IL-1) family cytokine release and pyroptosis. In particular, the Salmonella T3SS needle, inner rod, and flagellin proteins activate the NAIP/NLRC4 inflammasome in murine intestinal epithelial cells (IECs), which leads to restriction of bacterial replication and extrusion of infected IECs into the intestinal lumen, thereby preventing systemic dissemination of Salmonella. While these processes are quite well studied in mice, the role of the NAIP/NLRC4 inflammasome in human IECs remains unknown. Unexpectedly, we found the NAIP/NLRC4 inflammasome is dispensable for early inflammasome responses to Salmonella in both human IEC lines and enteroids. Additionally, NLRP3 and the adaptor protein ASC are not required for inflammasome activation in Caco-2 cells. Instead, we observed a necessity for caspase-4 and gasdermin D pore-forming activity in mediating inflammasome responses to Salmonella in Caco-2 cells. These findings suggest that unlike murine IECs, human IECs do not rely on NAIP/NLRC4 or NLRP3/ASC inflammasomes and instead primarily use caspase-4 to mediate inflammasome responses to Salmonella pathogenicity island 1 (SPI-1)-expressing Salmonella.
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Affiliation(s)
- Nawar Naseer
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Jenna Zhang
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Renate Bauer
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
- Department of Biosciences, Paris Lodron University of Salzburg, Salzburg, Austria
| | - David A. Constant
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | - Timothy J. Nice
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | - Igor E. Brodsky
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
| | - Isabella Rauch
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | - Sunny Shin
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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Cardiolipin Biosynthesis Genes Are Not Required for Salmonella enterica Serovar Typhimurium Pathogenesis in C57BL/6J Mice. Microbiol Spectr 2022; 10:e0261721. [PMID: 35638781 PMCID: PMC9241728 DOI: 10.1128/spectrum.02617-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Salmonella enterica serovar Typhimurium is an intracellular pathogen that parasitizes macrophages from within a vacuole. The vacuolar environment prompts the bacterium to regulate the lipid composition of the outer membrane (OM), and this influences host inflammation. S. Typhimurium regulates the levels of acidic glycerophospholipids known as cardiolipins (CL) within the OM, and mitochondrial CL molecules can prime and activate host inflammasomes. However, the contribution of S. Typhimurium’s CL biosynthesis genes to intracellular survival, inflammasome activation, and pathogenesis had not been examined. S. Typhimurium genes encode three CL synthases. Single, double, and triple mutants were constructed. Similar to other Enterobacteriaceae, ClsA is the primary CL synthase for S. Typhimurium during logarithmic growth, while ClsB and ClsC contribute CL production in stationary phase. It was necessary to delete all three genes to diminish the CL content of the envelope. Despite being devoid of CL molecules, ΔclsABC mutants were highly virulent during oral and systemic infection for C57BL/6J mice. In macrophages, ΔclsA, ΔclsB, ΔclsC, and ΔclsAC mutants behaved like the wild type, whereas ΔclsAB, ΔclsBC, and ΔclsABC mutants were attenuated and elicited reduced amounts of secreted interleukin-1 beta (IL-1β), IL-18, and lactate dehydrogenase. Hence, when clsA and clsC are deleted, clsB is necessary and sufficient to promote intracellular survival and inflammasome activation. Similarly, when clsB is deleted, clsA and clsC are necessary and sufficient. Therefore, the three CL synthase genes cooperatively and redundantly influence S. Typhimurium inflammasome activation and intracellular survival in C57BL/6J mouse macrophages but are dispensable for virulence in mice. IMPORTANCESalmonella enterica serovar Typhimurium is a pathogenic Gram-negative bacterium that regulates the cardiolipin (CL) and lipopolysaccharide (LPS) composition of the outer membrane (OM) during infection. Mitochondrial CL molecules activate the inflammasome and its effector caspase-1, which initiates an inflammatory process called pyroptosis. Purified bacterial CL molecules also influence LPS activation of Toll-like receptor 4 (Tlr4). S. Typhimurium resides within macrophage vacuoles and activates Tlr4 and the inflammasome during infection. However, the contribution of the three bacterial CL synthase genes (cls) to microbial pathogenesis and inflammation had not been tested. This study supports that the genes encoding the CL synthases work coordinately to promote intracellular survival in macrophages and to activate the inflammasome but do not influence inflammatory cytokine production downstream of Tlr4 or virulence in C57BL/6J mice. The macrophage phenotypes are not directly attributable to CL production but are caused by deleting specific combinations of cls gene products.
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Challagundla N, Saha B, Agrawal-Rajput R. Insights into inflammasome regulation: cellular, molecular, and pathogenic control of inflammasome activation. Immunol Res 2022; 70:578-606. [PMID: 35610534 DOI: 10.1007/s12026-022-09286-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 05/04/2022] [Indexed: 02/07/2023]
Abstract
Maintenance of immune homeostasis is an intricate process wherein inflammasomes play a pivotal role by contributing to innate and adaptive immune responses. Inflammasomes are ensembles of adaptor proteins that can trigger a signal following innate sensing of pathogens or non-pathogens eventuating in the inductions of IL-1β and IL-18. These inflammatory cytokines substantially influence the antigen-presenting cell's costimulatory functions and T helper cell differentiation, contributing to adaptive immunity. As acute and chronic disease conditions may accompany parallel tissue damage, we analyze the critical role of extracellular factors such as cytokines, amyloids, cholesterol crystals, etc., intracellular metabolites, and signaling molecules regulating inflammasome activation/inhibition. We develop an operative framework for inflammasome function and regulation by host cell factors and pathogens. While inflammasomes influence the innate and adaptive immune components' interplay modulating the anti-pathogen adaptive immune response, pathogens may target inflammasome inhibition as a survival strategy. As trapped between health and diseases, inflammasomes serve as promising therapeutic targets and their modus operandi serves as a scientific rationale for devising better therapeutic strategies.
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Affiliation(s)
- Naveen Challagundla
- Immunology lab, Indian Institute of Advanced Research, Gandhinagar, Gujarat, 382007, India
| | - Bhaskar Saha
- National Centre for Cell Science, Lab-5, Ganeshkhind, Pune, Maharashtra, 411007, India
| | - Reena Agrawal-Rajput
- Immunology lab, Indian Institute of Advanced Research, Gandhinagar, Gujarat, 382007, India.
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Salmonella Enteritidis GalE Protein Inhibits LPS-Induced NLRP3 Inflammasome Activation. Microorganisms 2022; 10:microorganisms10050911. [PMID: 35630356 PMCID: PMC9145252 DOI: 10.3390/microorganisms10050911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 04/23/2022] [Accepted: 04/24/2022] [Indexed: 02/01/2023] Open
Abstract
Microbial infection can trigger the assembly of inflammasomes and promote secretion of cytokines, such as IL-1β and IL-18. It is well-known that Salmonella modulates the activation of NLRC4 (NLR family CARD domain-containing protein 4) and NLRP3 (NLR family pyrin domain-containing 3) inflammasomes, however the mechanisms whereby Salmonella avoids or delays inflammasome activation remain largely unknown. Therefore, we used Salmonella Enteritidis C50336ΔfliC transposon library to screen for genes involved in modulating inflammasomes activation. The screen revealed the galactose metabolism-related gene galE to be essential for inflammasome activation. Here, we found that inflammasome activation was significantly increased in J774A.1 cells or wild-type bone marrow-derived macrophages (BMDMs) during infection by ΔfliCΔgalE compared to cells infected with ΔfliC. Importantly, we found that secretion of IL-1β was Caspase-1-dependent, consistent with canonical NLRP3 inflammasome activation. Furthermore, the virulence of ΔfliCΔgalE was significantly decreased compared to ΔfliC in a mouse model. Finally, RNA-seq analysis showed that multiple signaling pathways related to the inflammasome were subject to regulation by GalE. Taken together, our results suggest that GalE plays an important role in the regulatory network of Salmonella evasion of inflammasome activation.
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