1
|
Kodi T, Sankhe R, Gopinathan A, Nandakumar K, Kishore A. New Insights on NLRP3 Inflammasome: Mechanisms of Activation, Inhibition, and Epigenetic Regulation. J Neuroimmune Pharmacol 2024; 19:7. [PMID: 38421496 PMCID: PMC10904444 DOI: 10.1007/s11481-024-10101-5] [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: 03/07/2023] [Accepted: 11/06/2023] [Indexed: 03/02/2024]
Abstract
Inflammasomes are important modulators of inflammation. Dysregulation of inflammasomes can enhance vulnerability to conditions such as neurodegenerative diseases, autoinflammatory diseases, and metabolic disorders. Among various inflammasomes, Nucleotide-binding oligomerization domain leucine-rich repeat and pyrin domain-containing protein 3 (NLRP3) is the best-characterized inflammasome related to inflammatory and neurodegenerative diseases. NLRP3 is an intracellular sensor that recognizes pathogen-associated molecular patterns and damage-associated patterns resulting in the assembly and activation of NLRP3 inflammasome. The NLRP3 inflammasome includes sensor NLRP3, adaptor apoptosis-associated speck-like protein (ASC), and effector cysteine protease procaspase-1 that plays an imperative role in caspase-1 stimulation which further initiates a secondary inflammatory response. Regulation of NLRP3 inflammasome ameliorates NLRP3-mediated diseases. Much effort has been invested in studying the activation, and exploration of specific inhibitors and epigenetic mechanisms controlling NLRP3 inflammasome. This review gives an overview of the established NLRP3 inflammasome assembly, its brief molecular mechanistic activations as well as a current update on specific and non-specific NLRP3 inhibitors that could be used in NLRP3-mediated diseases. We also focused on the recently discovered epigenetic mechanisms mediated by DNA methylation, histone alterations, and microRNAs in regulating the activation and expression of NLRP3 inflammasome, which has resulted in a novel method of gaining insight into the mechanisms that modulate NLRP3 inflammasome activity and introducing potential therapeutic strategies for CNS disorders.
Collapse
Affiliation(s)
- Triveni Kodi
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Runali Sankhe
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Adarsh Gopinathan
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Krishnadas Nandakumar
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Anoop Kishore
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India.
| |
Collapse
|
2
|
Chiarini A, Armato U, Gui L, Dal Prà I. "Other Than NLRP3" Inflammasomes: Multiple Roles in Brain Disease. Neuroscientist 2024; 30:23-48. [PMID: 35815856 DOI: 10.1177/10738584221106114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Human neuroinflammatory and neurodegenerative diseases, whose prevalence keeps rising, are still unsolved pathobiological/therapeutical problems. Among others, recent etiology hypotheses stressed as their main driver a chronic neuroinflammation, which is mediated by innate immunity-related protein oligomers: the inflammasomes. A panoply of exogenous and/or endogenous harmful agents activates inflammasomes' assembly, signaling, and IL-1β/IL-18 production and neural cells' pyroptotic death. The underlying concept is that inflammasomes' chronic activation advances neurodegeneration while their short-lasting operation restores tissue homeostasis. Hence, from a therapeutic standpoint, it is crucial to understand inflammasomes' regulatory mechanisms. About this, a deluge of recent studies focused on the NLRP3 inflammasome with suggestions that its pharmacologic block would hinder neurodegeneration. Yet hitherto no evidence proves this view. Moreover, known inflammasomes are numerous, and the mechanisms regulating their expression and function may vary with the involved animal species and strains, as well as organs and cells, and the harmful factors triggered as a result. Therefore, while presently leaving out some little-studied inflammasomes, this review focuses on the "other than NLRP3" inflammasomes that participate in neuroinflammation's complex mechanisms: NLRP1, NLRP2, NLRC4, and AIM2. Although human-specific data about them are relatively scant, we stress that only a holistic view including several human brain inflammasomes and other potential pathogenetic drivers will lead to successful therapies for neuroinflammatory and neurodegenerative diseases.
Collapse
Affiliation(s)
- Anna Chiarini
- Human Histology and Embryology Section, Department of Surgery, Dentistry, Pediatrics, and Gynecology, University of Verona, Verona, Italy
| | - Ubaldo Armato
- Human Histology and Embryology Section, Department of Surgery, Dentistry, Pediatrics, and Gynecology, University of Verona, Verona, Italy
| | - Li Gui
- Department of Neurology, Southwest Hospital, Chongqing, China
| | - Ilaria Dal Prà
- Human Histology and Embryology Section, Department of Surgery, Dentistry, Pediatrics, and Gynecology, University of Verona, Verona, Italy
| |
Collapse
|
3
|
Ahn M, Chen VCW, Rozario P, Ng WL, Kong PS, Sia WR, Kang AEZ, Su Q, Nguyen LH, Zhu F, Chan WOY, Tan CW, Cheong WS, Hey YY, Foo R, Guo F, Lim YT, Li X, Chia WN, Sobota RM, Fu NY, Irving AT, Wang LF. Bat ASC2 suppresses inflammasomes and ameliorates inflammatory diseases. Cell 2023; 186:2144-2159.e22. [PMID: 37172565 DOI: 10.1016/j.cell.2023.03.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/12/2022] [Accepted: 03/31/2023] [Indexed: 05/15/2023]
Abstract
Bats are special in their ability to live long and host many emerging viruses. Our previous studies showed that bats have altered inflammasomes, which are central players in aging and infection. However, the role of inflammasome signaling in combating inflammatory diseases remains poorly understood. Here, we report bat ASC2 as a potent negative regulator of inflammasomes. Bat ASC2 is highly expressed at both the mRNA and protein levels and is highly potent in inhibiting human and mouse inflammasomes. Transgenic expression of bat ASC2 in mice reduced the severity of peritonitis induced by gout crystals and ASC particles. Bat ASC2 also dampened inflammation induced by multiple viruses and reduced mortality of influenza A virus infection. Importantly, it also suppressed SARS-CoV-2-immune-complex-induced inflammasome activation. Four key residues were identified for the gain of function of bat ASC2. Our results demonstrate that bat ASC2 is an important negative regulator of inflammasomes with therapeutic potential in inflammatory diseases.
Collapse
Affiliation(s)
- Matae Ahn
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore; SingHealth Duke-NUS Medicine Academic Clinical Program, Singapore 168753, Singapore; SingHealth PGY1 Residency Program, Singapore 169608, Singapore; Department of Internal Medicine, Singapore General Hospital, Singapore 169608, Singapore.
| | - Vivian Chih-Wei Chen
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Pritisha Rozario
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Wei Lun Ng
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Pui San Kong
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Wan Rong Sia
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Adrian Eng Zheng Kang
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Qi Su
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Lan Huong Nguyen
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Feng Zhu
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Wharton O Y Chan
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Chee Wah Tan
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Wan Shoo Cheong
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Ying Ying Hey
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Randy Foo
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Fusheng Guo
- Programme in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Yan Ting Lim
- Functional Proteomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A(∗)STAR), Singapore 138673, Singapore; SingMass - National Mass Spectrometry Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A(∗)STAR), Singapore 138673, Singapore
| | - Xin Li
- Functional Proteomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A(∗)STAR), Singapore 138673, Singapore; SingMass - National Mass Spectrometry Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A(∗)STAR), Singapore 138673, Singapore
| | - Wan Ni Chia
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Radoslaw M Sobota
- Functional Proteomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A(∗)STAR), Singapore 138673, Singapore; SingMass - National Mass Spectrometry Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A(∗)STAR), Singapore 138673, Singapore
| | - Nai Yang Fu
- Programme in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Aaron T Irving
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore; Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Zhejiang University, Haining 314400, China; Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Lin-Fa Wang
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore; SingHealth Duke-NUS Global Health Institute, Singapore 169857, Singapore.
| |
Collapse
|
4
|
de Almeida L, Devi S, Indramohan M, Huang QQ, Ratsimandresy RA, Pope RM, Dorfleutner A, Stehlik C. POP1 inhibits MSU-induced inflammasome activation and ameliorates gout. Front Immunol 2022; 13:912069. [PMID: 36225929 PMCID: PMC9550078 DOI: 10.3389/fimmu.2022.912069] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 09/06/2022] [Indexed: 01/13/2023] Open
Abstract
Canonical inflammasomes are innate immune protein scaffolds that enable the activation of inflammatory caspase-1, and subsequently the processing and release of interleukin (IL)-1β, IL-18, and danger signals, as well as the induction of pyroptotic cell death. Inflammasome assembly and activation occurs in response to sensing of infectious, sterile and self-derived molecular patterns by cytosolic pattern recognition receptors, including the Nod-like receptor NLRP3. While these responses are essential for host defense, excessive and uncontrolled NLRP3 inflammasome responses cause and contribute to a wide spectrum of inflammatory diseases, including gout. A key step in NLRP3 inflammasome assembly is the sequentially nucleated polymerization of Pyrin domain (PYD)- and caspase recruitment domain (CARD)-containing inflammasome components. NLRP3 triggers polymerization of the adaptor protein ASC through PYD-PYD interactions, but ASC polymerization then proceeds in a self-perpetuating manner and represents a point of no return, which culminates in the activation of caspase-1 by induced proximity. In humans, small PYD-only proteins (POPs) lacking an effector domain regulate this key process through competitive binding, but limited information exists on their physiological role during health and disease. Here we demonstrate that POP1 expression in macrophages is sufficient to dampen MSU crystal-mediated inflammatory responses in animal models of gout. Whether MSU crystals are administered into a subcutaneous airpouch or into the ankle joint, the presence of POP1 significantly reduces neutrophil infiltration. Also, airpouch exudates have much reduced IL-1β and ASC, which are typical pro-inflammatory indicators that can also be detected in synovial fluids of gout patients. Exogenous expression of POP1 in mouse and human macrophages also blocks MSU crystal-induced NLRP3 inflammasome assembly, resulting in reduced IL-1β and IL-18 secretion. Conversely, reduced POP1 expression in human macrophages enhances IL-1β secretion. We further determined that the mechanism for the POP1-mediated inhibition of NLRP3 inflammasome activation is through its interference with the crucial NLRP3 and ASC interaction within the inflammasome complex. Strikingly, administration of an engineered cell permeable version of POP1 was able to ameliorate MSU crystal-mediated inflammation in vivo, as measured by neutrophil infiltration. Overall, we demonstrate that POP1 may play a crucial role in regulating inflammatory responses in gout.
Collapse
Affiliation(s)
- Lucia de Almeida
- 1Division of Rheumatology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Savita Devi
- 2Department of Academic Pathology, Cedars Sinai Medical Center, Los Angeles, CA, United States
| | - Mohanalaxmi Indramohan
- 2Department of Academic Pathology, Cedars Sinai Medical Center, Los Angeles, CA, United States
| | - Qi-Quan Huang
- 1Division of Rheumatology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Rojo A. Ratsimandresy
- 2Department of Academic Pathology, Cedars Sinai Medical Center, Los Angeles, CA, United States
| | - Richard M. Pope
- 1Division of Rheumatology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Andrea Dorfleutner
- 2Department of Academic Pathology, Cedars Sinai Medical Center, Los Angeles, CA, United States,3Department of Biomedical Sciences, Cedars Sinai Medical Center, Los Angeles, CA, United States,4The Kao Autoimmunity Institute, Cedars Sinai Medical Center, Los Angeles, CA, United States,*Correspondence: Andrea Dorfleutner, ; Christian Stehlik,
| | - Christian Stehlik
- 2Department of Academic Pathology, Cedars Sinai Medical Center, Los Angeles, CA, United States,3Department of Biomedical Sciences, Cedars Sinai Medical Center, Los Angeles, CA, United States,4The Kao Autoimmunity Institute, Cedars Sinai Medical Center, Los Angeles, CA, United States,5Samuel Oschin Comprehensive Cancer Institute, Cedars Sinai Medical Center, Los Angeles, CA, United States,*Correspondence: Andrea Dorfleutner, ; Christian Stehlik,
| |
Collapse
|
5
|
Nagar A, Rahman T, Harton JA. The ASC Speck and NLRP3 Inflammasome Function Are Spatially and Temporally Distinct. Front Immunol 2021; 12:752482. [PMID: 34745125 PMCID: PMC8566762 DOI: 10.3389/fimmu.2021.752482] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/23/2021] [Indexed: 01/20/2023] Open
Abstract
Although considered the ternary inflammasome structure, whether the singular, perinuclear NLRP3:ASC speck is synonymous with the NLRP3 inflammasome is unclear. Herein, we report that the NLRP3:ASC speck is not required for nigericin-induced inflammasome activation but facilitates and maximizes IL-1β processing. Furthermore, the NLRP3 agonists H2O2 and MSU elicited IL-1β maturation without inducing specks. Notably, caspase-1 activity is spatially distinct from the speck, occurring at multiple cytoplasmic sites. Additionally, caspase-1 activity negatively regulates speck frequency and speck size, while speck numbers and IL-1β processing are negatively correlated, cyclical and can be uncoupled by NLRP3 mutations or inhibiting microtubule polymerization. Finally, when specks are present, caspase-1 is likely activated after leaving the speck structure. Thus, the speck is not the NLRP3 inflammasome itself, but is instead a dynamic structure which may amplify the NLRP3 response to weak stimuli by facilitating the formation and release of small NLRP3:ASC complexes which in turn activate caspase-1.
Collapse
Affiliation(s)
- Abhinit Nagar
- Department of Immunology & Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Tabassum Rahman
- Department of Immunology & Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Jonathan A Harton
- Department of Immunology & Microbial Disease, Albany Medical College, Albany, NY, United States
| |
Collapse
|
6
|
Dubuisson N, Versele R, Davis-López de Carrizosa MA, Selvais CM, Brichard SM, Abou-Samra M. Walking down Skeletal Muscle Lane: From Inflammasome to Disease. Cells 2021; 10:cells10113023. [PMID: 34831246 PMCID: PMC8616386 DOI: 10.3390/cells10113023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 12/14/2022] Open
Abstract
Over the last decade, innate immune system receptors and sensors called inflammasomes have been identified to play key pathological roles in the development and progression of numerous diseases. Among them, the nucleotide-binding oligomerization domain (NOD-), leucine-rich repeat (LRR-) and pyrin domain-containing protein 3 (NLRP3) inflammasome is probably the best characterized. To date, NLRP3 has been extensively studied in the heart, where its effects and actions have been broadly documented in numerous cardiovascular diseases. However, little is still known about NLRP3 implications in muscle disorders affecting non-cardiac muscles. In this review, we summarize and present the current knowledge regarding the function of NLRP3 in diseased skeletal muscle, and discuss the potential therapeutic options targeting the NLRP3 inflammasome in muscle disorders.
Collapse
Affiliation(s)
- Nicolas Dubuisson
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain, 1200 Brussels, Belgium; (R.V.); (M.A.D.-L.d.C.); (C.M.S.); (S.M.B.); (M.A.-S.)
- Neuromuscular Reference Center, Cliniques Universitaires Saint-Luc, Avenue Hippocrate 10, 1200 Brussels, Belgium
- Correspondence:
| | - Romain Versele
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain, 1200 Brussels, Belgium; (R.V.); (M.A.D.-L.d.C.); (C.M.S.); (S.M.B.); (M.A.-S.)
| | - María A. Davis-López de Carrizosa
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain, 1200 Brussels, Belgium; (R.V.); (M.A.D.-L.d.C.); (C.M.S.); (S.M.B.); (M.A.-S.)
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Camille M. Selvais
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain, 1200 Brussels, Belgium; (R.V.); (M.A.D.-L.d.C.); (C.M.S.); (S.M.B.); (M.A.-S.)
| | - Sonia M. Brichard
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain, 1200 Brussels, Belgium; (R.V.); (M.A.D.-L.d.C.); (C.M.S.); (S.M.B.); (M.A.-S.)
| | - Michel Abou-Samra
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain, 1200 Brussels, Belgium; (R.V.); (M.A.D.-L.d.C.); (C.M.S.); (S.M.B.); (M.A.-S.)
| |
Collapse
|
7
|
Devi S, Stehlik C, Dorfleutner A. An Update on CARD Only Proteins (COPs) and PYD Only Proteins (POPs) as Inflammasome Regulators. Int J Mol Sci 2020; 21:E6901. [PMID: 32962268 PMCID: PMC7555848 DOI: 10.3390/ijms21186901] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 09/17/2020] [Accepted: 09/17/2020] [Indexed: 12/18/2022] Open
Abstract
Inflammasomes are protein scaffolds required for the activation of caspase-1 and the subsequent release of interleukin (IL)-1β, IL-18, and danger signals, as well as the induction of pyroptotic cell death to restore homeostasis following infection and sterile tissue damage. However, excessive inflammasome activation also causes detrimental inflammatory disease. Therefore, extensive control mechanisms are necessary to prevent improper inflammasome responses and inflammatory disease. Inflammasomes are assembled by sequential nucleated polymerization of Pyrin domain (PYD) and caspase recruitment domain (CARD)-containing inflammasome components. Once polymerization is nucleated, this process proceeds in a self-perpetuating manner and represents a point of no return. Therefore, regulation of this key step is crucial for a controlled inflammasome response. Here, we provide an update on two single domain protein families containing either a PYD or a CARD, the PYD-only proteins (POPs) and CARD-only proteins (COPs), respectively. Their structure allows them to occupy and block access to key protein-protein interaction domains necessary for inflammasome assembly, thereby regulating the threshold of these nucleated polymerization events, and consequently, the inflammatory host response.
Collapse
Affiliation(s)
- Savita Devi
- Department of Pathology and Laboratory Medicine, Cedars Sinai, Los Angeles, CA 90048, USA;
| | - Christian Stehlik
- Department of Pathology and Laboratory Medicine, Cedars Sinai, Los Angeles, CA 90048, USA;
- Department of Biomedical Sciences, and Samuel Oschin Comprehensive Cancer Institute, Cedars Sinai, Los Angeles, CA 90048, USA
| | - Andrea Dorfleutner
- Department of Pathology and Laboratory Medicine, Cedars Sinai, Los Angeles, CA 90048, USA;
- Department of Biomedical Sciences, Cedars Sinai, Los Angeles, CA 90048, USA
| |
Collapse
|
8
|
Rahman T, Nagar A, Duffy EB, Okuda K, Silverman N, Harton JA. NLRP3 Sensing of Diverse Inflammatory Stimuli Requires Distinct Structural Features. Front Immunol 2020; 11:1828. [PMID: 32983094 PMCID: PMC7479093 DOI: 10.3389/fimmu.2020.01828] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/08/2020] [Indexed: 12/30/2022] Open
Abstract
The NLRP3 inflammasome is central to host defense and implicated in various inflammatory diseases and conditions. While the favored paradigm of NLRP3 inflammasome activation stipulates a unifying signal intermediate that de-represses NLRP3, this view has not been tested. Further, structures within NLRP3 required for inflammasome activation are poorly defined. Here we demonstrate that while the NLRP3 LRRs are not auto-repressive and are not required for inflammasome activation by all agonists, distinct sequences within the NLRP3 LRRs positively and negatively modulate inflammasome activation by specific ligands. In addition, elements within the HD1/HD2 “hinge” of NLRP3 and the nucleotide-binding domain have contrasting functions depending upon the specific agonists. Further, while NLRP3 1–432 is minimally sufficient for inflammasome activation by all agonists tested, the pyrin, and linker domains (1–134) function cooperatively and are sufficient for inflammasome activation by certain agonists. Conserved cysteines 8 and 108 appear important for inflammasome activation by sterile, but not infectious insults. Our results define common and agonist-specific regions of NLRP3 that likely mediate ligand-specific responses, discount the hypothesis that NLRP3 inflammasome activation has a unified mechanism, and implicate NLRP3 as an integrator of agonist-specific, inflammasome activating signals.
Collapse
Affiliation(s)
- Tabassum Rahman
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Abhinit Nagar
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Ellen B Duffy
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Kendi Okuda
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States
| | - Neal Silverman
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States
| | - Jonathan A Harton
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| |
Collapse
|
9
|
Aral K, Milward MR, Kapila Y, Berdeli A, Cooper PR. Inflammasomes and their regulation in periodontal disease: A review. J Periodontal Res 2020; 55:473-487. [PMID: 31960443 DOI: 10.1111/jre.12733] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/15/2019] [Accepted: 12/28/2019] [Indexed: 12/12/2022]
Abstract
Interleukin-1β (IL-1β), which is secreted by host tissues leading to periodontal tissue inflammation, is a major pro-inflammatory cytokine in the pathogenesis of periodontal disease. The conversion of pro-IL-1β into its biologically active form is controlled by multiprotein complexes named as inflammasomes, which are key regulator of host defense mechanisms and inflammasome involved diseases, including the periodontal diseases. Inflammasomes are regulated by different proteins and processes, including pyrin domain (PYD)-only proteins (POPs), CARD-only proteins (COPs), tripartite motif family proteins (TRIMs), autophagy, and interferons. A review of in vitro, in vivo, and clinical data from these publications revealed that several inflammasomes including (NOD)-like receptor (NLR) pyrin domain-containing 3 (NLRP3) and absent in melanoma 2 (AIM2) have been found to be involved in periodontal disease pathogenesis. To the best of our knowledge, the current article provides the first review of the literature focusing on studies that evaluated both inflammasomes and their regulators in periodontal disease. An upregulation for inflammasomes and a downregulation of inflammasome regulator proteins including POPs, COPs, and TRIMs have been reported in periodontal disease. Although interferons (types I and II) and autophagy have been found to be involved in periodontal disease, their possible role in inflammasome activation has not evaluated yet. Modulating the excessive inflammatory response by the use of inflammasome regulators may have potential in the management of periodontal disease.
Collapse
Affiliation(s)
- Kübra Aral
- Oral Biology, School of Dentistry, University of Birmingham, Birmingham, UK.,Republic of Turkey Ministry of Health, Ankara, Turkey
| | - Michael R Milward
- Periodontology, School of Dentistry, University of Birmingham, Birmingham, UK
| | - Yvonne Kapila
- Orofacial Sciences, The School of Dentistry, University of California San Francisco, San Francisco, CA, USA
| | - Afig Berdeli
- Molecular Genetics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Paul R Cooper
- Oral Biology, School of Dentistry, University of Birmingham, Birmingham, UK.,Department of Oral Sciences, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| |
Collapse
|
10
|
Aral K, Berdeli E, Cooper PR, Milward MR, Kapila Y, Karadede Ünal B, Aral CA, Berdeli A. Differential expression of inflammasome regulatory transcripts in periodontal disease. J Periodontol 2019; 91:606-616. [PMID: 31557327 DOI: 10.1002/jper.19-0222] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/12/2019] [Accepted: 07/30/2019] [Indexed: 11/08/2022]
Abstract
BACKGROUND The inflammasome modulates the release of key proinflammatory cytokines associated with periodontal disease pathogenesis. The aim of this study was to evaluate the expression of proteins that regulate the inflammasome, namely pyrin domain-only proteins (POPs), caspase activation recruitment domain (CARD)-only proteins, and tripartite motif-containing (TRIM) proteins, in periodontal diseases. METHODS A total of 68 participants (34 males and 34 females) were divided into four groups, including periodontal health (H), gingivitis (G), chronic periodontitis (CP), and aggressive periodontitis (AgP) based on clinical parameters. Gingival tissue samples were obtained from all participants for reverse transcription polymerase chain reaction (RT-PCR)-based gene expression analyses of molecules that regulate the inflammasome, including apoptosis-associated speck-like protein (ASC) containing CARD, caspase-1, interleukin-1β (IL-1β), interleukin-18 (IL-18), nucleotide-binding domain, leucine rich family (NLR) pyrin domain containing 3 (NLRP3), NLR family pyrin domain containing 2 (NLRP2), AIM2 (absent in melanoma 2), POP1, POP2, CARD16, CARD18, TRIM16, and TRIM20 by RT-PCR. RESULTS NLRP3 and IL-1β were upregulated in the G, CP, and AgP groups compared with group H (P < 0.05). AIM2 was downregulated in the CP group compared with the H, G, and AgP groups (P < 0.05). TRIM20, TRIM16, and CARD18 were downregulated in the G, CP, and AgP groups compared with the H group (P < 0.05). POP1 and POP2 were downregulated in the CP and AgP, and AgP and G groups, respectively (P < 0.05). CONCLUSION Active periodontal disease may result in downregulation of inflammasome regulators that may increase the activity of NLRP3 and IL-1β in periodontal disease.
Collapse
Affiliation(s)
- Kübra Aral
- Oral Biology, School of Dentistry, University of Birmingham, Birmingham, UK
| | - Eynar Berdeli
- Faculty of Dentistry, Izmir Katip Celebi University, Izmir, Turkey
| | - Paul Roy Cooper
- School of Dentistry, University of Birmingham, Birmingham, UK
| | | | - Yvonne Kapila
- The School of Dentistry, University of California San Francisco, San Francisco, CA, USA
| | | | | | - Afig Berdeli
- Faculty of Medicine, Molecular Medicine Laboratory, Ege University, Izmir, Turkey
| |
Collapse
|
11
|
Abstract
The inflammasome is a multi-molecular platform crucial to the induction of an inflammatory response to cellular danger. Recognition in the cytoplasm of endogenously and exogenously derived ligands initiates conformational change in sensor proteins, such as NLRP3, that permits the subsequent rapid recruitment of adaptor proteins, like ASC, and the resulting assembly of a large-scale inflammatory signalling platform. The assembly process is driven by sensor-sensor interactions as well as sensor-adaptor and adaptor-adaptor interactions. The resulting complex, which can reach diameters of around 1 micron, has a variable composition and stoichiometry. The inflammasome complex functions as a platform for the proximity induced activation of effector caspases, such as caspase-1 and caspase-8. This ultimately leads to the processing of the inflammatory cytokines pro-IL1β and pro-IL18 into their active forms, along with the cleavage of Gasdermin D, a key activator of cell death via pyroptosis.
Collapse
|
12
|
Polydatin suppresses proliferation and metastasis of non-small cell lung cancer cells by inhibiting NLRP3 inflammasome activation via NF-κB pathway. Biomed Pharmacother 2018; 108:130-136. [DOI: 10.1016/j.biopha.2018.09.051] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 09/07/2018] [Accepted: 09/08/2018] [Indexed: 01/19/2023] Open
|
13
|
Nanson JD, Rahaman MH, Ve T, Kobe B. Regulation of signaling by cooperative assembly formation in mammalian innate immunity signalosomes by molecular mimics. Semin Cell Dev Biol 2018; 99:96-114. [PMID: 29738879 DOI: 10.1016/j.semcdb.2018.05.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 03/18/2018] [Accepted: 05/04/2018] [Indexed: 12/16/2022]
Abstract
Innate immunity pathways constitute the first line of defense against infections and cellular damage. An emerging concept in these pathways is that signaling involves the formation of finite (e.g. rings in NLRs) or open-ended higher-order assemblies (e.g. filamentous assemblies by members of the death-fold family and TIR domains). This signaling by cooperative assembly formation (SCAF) mechanism allows rapid and strongly amplified responses to minute amounts of stimulus. While the characterization of the molecular mechanisms of SCAF has seen rapid progress, little is known about its regulation. One emerging theme involves proteins produced both in host cells and by pathogens that appear to mimic the signaling components. Recently characterized examples involve the capping of the filamentous assemblies formed by caspase-1 CARDs by the CARD-only protein INCA, and those formed by caspase-8 by the DED-containing protein MC159. By contrast, the CARD-only protein ICEBERG and the DED-containing protein cFLIP incorporate into signaling filaments and presumably interfere with proximity based activation of caspases. We review selected examples of SCAF in innate immunity pathways and focus on the current knowledge on signaling component mimics produced by mammalian and pathogen cells and what is known about their mechanisms of action.
Collapse
Affiliation(s)
- Jeffrey D Nanson
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Md Habibur Rahaman
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Thomas Ve
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia; Institute for Glycomics, Griffith University, Southport, QLD, 4222, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia.
| |
Collapse
|
14
|
Abstract
A complex interplay between pathogen and host determines the immune response during viral infection. A set of cytosolic sensors are expressed by immune cells to detect viral infection. NOD-like receptors (NLRs) comprise a large family of intracellular pattern recognition receptors. Members of the NLR family assemble into large multiprotein complexes, termed inflammasomes, which induce downstream immune responses to specific pathogens, environmental stimuli, and host cell damage. Inflammasomes are composed of cytoplasmic sensor molecules such as NLRP3 or absent in melanoma 2 (AIM2), the adaptor protein ASC (apoptosis-associated speck-like protein containing caspase recruitment domain), and the effector protein procaspase-1. The inflammasome operates as a platform for caspase-1 activation, resulting in caspase-1-dependent proteolytic maturation and secretion of interleukin (IL)-1β and IL-18. This, in turn, activates the expression of other immune genes and facilitates lymphocyte recruitment to the site of primary infection, thereby controlling invading pathogens. Moreover, inflammasomes counter viral replication and remove infected immune cells through an inflammatory cell death, program termed as pyroptosis. As a countermeasure, viral pathogens have evolved virulence factors to antagonise inflammasome pathways. In this review, we discuss the role of inflammasomes in sensing viral infection as well as the evasion strategies that viruses have developed to evade inflammasome-dependent immune responses. This information summarises our understanding of host defence mechanisms against viruses and highlights research areas that can provide new approaches to interfere in the pathogenesis of viral diseases.
Collapse
|
15
|
Indramohan M, Stehlik C, Dorfleutner A. COPs and POPs Patrol Inflammasome Activation. J Mol Biol 2017; 430:153-173. [PMID: 29024695 DOI: 10.1016/j.jmb.2017.10.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 09/28/2017] [Accepted: 10/04/2017] [Indexed: 01/07/2023]
Abstract
Sensing and responding to pathogens and tissue damage is a core mechanism of innate immune host defense, and inflammasomes represent a central cytosolic pattern recognition receptor pathway leading to the generation of the pro-inflammatory cytokines interleukin-1β and interleukin-18 and pyroptotic cell death that causes the subsequent release of danger signals to propagate and perpetuate inflammatory responses. While inflammasome activation is essential for host defense, deregulated inflammasome responses and excessive release of inflammatory cytokines and danger signals are linked to an increasing spectrum of inflammatory diseases. In this review, we will discuss recent developments in elucidating the role of PYRIN domain-only proteins (POPs) and the related CARD-only proteins (COPs) in regulating inflammasome responses and their impact on inflammatory disease.
Collapse
Affiliation(s)
- Mohanalaxmi Indramohan
- Division of Rheumatology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Christian Stehlik
- Division of Rheumatology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Robert H. Lurie Comprehensive Cancer Center, Interdepartmental Immunobiology Center and Skin Disease Research Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
| | - Andrea Dorfleutner
- Division of Rheumatology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
| |
Collapse
|
16
|
Baker PJ, De Nardo D, Moghaddas F, Tran LS, Bachem A, Nguyen T, Hayman T, Tye H, Vince JE, Bedoui S, Ferrero RL, Masters SL. Posttranslational Modification as a Critical Determinant of Cytoplasmic Innate Immune Recognition. Physiol Rev 2017; 97:1165-1209. [DOI: 10.1152/physrev.00026.2016] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 02/27/2017] [Accepted: 02/28/2017] [Indexed: 12/21/2022] Open
Abstract
Cell surface innate immune receptors can directly detect a variety of extracellular pathogens to which cytoplasmic innate immune sensors are rarely exposed. Instead, within the cytoplasm, the environment is rife with cellular machinery and signaling pathways that are indirectly perturbed by pathogenic microbes to activate intracellular sensors, such as pyrin, NLRP1, NLRP3, or NLRC4. Therefore, subtle changes in key intracellular processes such as phosphorylation, ubiquitination, and other pathways leading to posttranslational protein modification are key determinants of innate immune recognition in the cytoplasm. This concept is critical to establish the “guard hypothesis” whereby otherwise homeostatic pathways that keep innate immune sensors at bay are released in response to alterations in their posttranslational modification status. Originally identified in plants, evidence that a similar guardlike mechanism exists in humans has recently been identified, whereby a mutation that prevents phosphorylation of the innate immune sensor pyrin triggers a dominantly inherited autoinflammatory disease. It is also noteworthy that even when a cytoplasmic innate immune sensor has a direct ligand, such as bacterial peptidoglycan (NOD1 or NOD2), RNA (RIG-I or MDA5), or DNA (cGAS or IFI16), it can still be influenced by posttranslational modification to dramatically alter its response. Therefore, due to their existence in the cytoplasmic milieu, posttranslational modification is a key determinant of intracellular innate immune receptor functionality.
Collapse
Affiliation(s)
- Paul J. Baker
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Dominic De Nardo
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Fiona Moghaddas
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Le Son Tran
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Annabell Bachem
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Tan Nguyen
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Thomas Hayman
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Hazel Tye
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - James E. Vince
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Sammy Bedoui
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Richard L. Ferrero
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| | - Seth L. Masters
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Hudson Institute of Medical Research, Monash University, Centre for Innate Immunity and Infectious Diseases, Clayton, Victoria, Australia; The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; and Departments of Medical Biology and of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
| |
Collapse
|
17
|
Pyrin-only protein 2 limits inflammation but improves protection against bacteria. Nat Commun 2017; 8:15564. [PMID: 28580947 PMCID: PMC5512670 DOI: 10.1038/ncomms15564] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 04/07/2017] [Indexed: 12/13/2022] Open
Abstract
Pyrin domain-only proteins (POPs) are recently evolved, primate-specific proteins demonstrated in vitro as negative regulators of inflammatory responses. However, their in vivo function is not understood. Of the four known POPs, only POP2 is reported to regulate NF-κB-dependent transcription and multiple inflammasomes. Here we use a transgenic mouse-expressing POP2 controlled by its endogenous human promotor to study the immunological functions of POP2. Despite having significantly reduced inflammatory cytokine responses to LPS and bacterial infection, POP2 transgenic mice are more resistant to bacterial infection than wild-type mice. In a pulmonary tularaemia model, POP2 enhances IFN-γ production, modulates neutrophil numbers, improves macrophage functions, increases bacterial control and diminishes lung pathology. Thus, unlike other POPs thought to diminish innate protection, POP2 reduces detrimental inflammation while preserving and enhancing protective immunity. Our findings suggest that POP2 acts as a high-order regulator balancing cellular function and inflammation with broad implications for inflammation-associated diseases and therapeutic intervention. Pyrin-only proteins (POPs) are primate-specific negative regulators of inflammasome activation. Here the authors generate transgenic mice expressing POP2 under the control of the human promoter, and show that POP2 is important for balancing antibacterial inflammatory responses in vivo.
Collapse
|
18
|
The PYRIN domain-only protein POP2 inhibits inflammasome priming and activation. Nat Commun 2017; 8:15556. [PMID: 28580931 PMCID: PMC5465353 DOI: 10.1038/ncomms15556] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 04/07/2017] [Indexed: 01/23/2023] Open
Abstract
Inflammasomes are protein platforms linking recognition of microbe, pathogen-associated and damage-associated molecular patterns by cytosolic sensory proteins to caspase-1 activation. Caspase-1 promotes pyroptotic cell death and the maturation and secretion of interleukin (IL)-1β and IL-18, which trigger inflammatory responses to clear infections and initiate wound-healing; however, excessive responses cause inflammatory disease. Inflammasome assembly requires the PYRIN domain (PYD)-containing adaptor ASC, and depends on PYD–PYD interactions. Here we show that the PYD-only protein POP2 inhibits inflammasome assembly by binding to ASC and interfering with the recruitment of ASC to upstream sensors, which prevents caspase-1 activation and cytokine release. POP2 also impairs macrophage priming by inhibiting the activation of non-canonical IκB kinase ɛ and IκBα, and consequently protects from excessive inflammation and acute shock in vivo. Our findings advance our understanding of the complex regulatory mechanisms that maintain a balanced inflammatory response and highlight important differences between individual POP members. Excessive inflammasome activation leads to inflammatory diseases, but how inflammasomes are regulated by PYD-only adaptors is unclear. Here the authors show that the PYD-only protein POP2 inhibits both inflammasome priming and assembly by interfering, respectively, with IκBα activation and NLRP3-ASC interaction.
Collapse
|
19
|
Hoss F, Rodriguez-Alcazar JF, Latz E. Assembly and regulation of ASC specks. Cell Mol Life Sci 2017; 74:1211-1229. [PMID: 27761594 PMCID: PMC11107573 DOI: 10.1007/s00018-016-2396-6] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/28/2016] [Accepted: 10/10/2016] [Indexed: 12/11/2022]
Abstract
The inflammasome adapter ASC links activated inflammasome sensors to the effector molecule pro-caspase-1. Recruitment of pro-caspase-1 to ASC promotes the autocatalytic activation of caspase-1, which leads to the release of pro-inflammatory cytokines, such as IL-1β. Upon triggering of inflammasome sensors, ASC assembles into large helical fibrils that interact with each other serving as a supramolecular signaling platform termed the ASC speck. Alternative splicing, post-translational modifications of ASC, as well as interaction with other proteins can perturb ASC function. In several inflammatory diseases, ASC specks can be found in the extracellular space and its presence correlates with poor prognosis. Here, we review the role of ASC in inflammation, and focus on the structural mechanisms that lead to ASC speck formation, the regulation of ASC function during inflammasome assembly, and the importance of ASC specks in disease.
Collapse
Affiliation(s)
- Florian Hoss
- Institute of Innate Immunity, University Hospitals, University of Bonn, Sigmund-Freud-Straße 25, 53127, Bonn, Germany
| | - Juan F Rodriguez-Alcazar
- Institute of Innate Immunity, University Hospitals, University of Bonn, Sigmund-Freud-Straße 25, 53127, Bonn, Germany
| | - Eicke Latz
- Institute of Innate Immunity, University Hospitals, University of Bonn, Sigmund-Freud-Straße 25, 53127, Bonn, Germany.
- Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, USA.
- German Center for Neurodegenerative Diseases, Bonn, Germany.
- Department of Cancer Research and Molecular Medicine, Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway.
| |
Collapse
|
20
|
Stewart MK, Cookson BT. Evasion and interference: intracellular pathogens modulate caspase-dependent inflammatory responses. Nat Rev Microbiol 2016; 14:346-59. [PMID: 27174147 DOI: 10.1038/nrmicro.2016.50] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Pathogens have evolved to complete the virulence cycle of colonization, replication and dissemination in intimate association with a complex network of extracellular and intracellular surveillance systems that guard tissue spaces. In this Review, we discuss the strategies used by bacteria and viruses to evade or inhibit intracellular detection that is coupled to pro-inflammatory caspase-dependent protective responses. Such strategies include alterations of lipopolysaccharide (LPS) structures, the regulated expression of components of type III secretion systems, and the utilization of proteins that inhibit inflammasome formation, the enzymatic activity of caspases and cytokine signalling. Inflammation is crucial in response to exposure to pathogens, but is potentially damaging and thus tightly regulated. The threshold for the activation of pro-inflammatory caspases is determined by the immediate stimulus in the context of previous signals. Pathogen, genetic and situational factors modulate this threshold, which determines the ability of the host to resist infection while minimizing harm.
Collapse
Affiliation(s)
- Mary K Stewart
- Department of Microbiology, University of Washington, Seattle, Washington 98195, USA
| | - Brad T Cookson
- Department of Microbiology, University of Washington, Seattle, Washington 98195, USA.,Department of Laboratory Medicine, University of Washington, Seattle, Washington 98195, USA
| |
Collapse
|
21
|
Matusiak M, Van Opdenbosch N, Lamkanfi M. CARD- and pyrin-only proteins regulating inflammasome activation and immunity. Immunol Rev 2016; 265:217-30. [PMID: 25879296 DOI: 10.1111/imr.12282] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Membrane-bound and intracellular immune receptors respond to microbial pathogens by initiating signaling cascades that result in production of inflammatory cytokines and antimicrobial factors. These host responses need to be tightly regulated to prevent tissue damage and other harmful consequences of excessive inflammation. CARD-only proteins (COPs) and Pyrin-only proteins (POPs) are human- and primate-specific dominant negative inhibitors that modulate inflammatory and innate immune responses. In addition, several poxviruses encode POPs that interfere with inflammatory and host defense responses. COPs and POPs modulate inflammatory signaling at several checkpoints by sequestering key components of the inflammasome and NF-κB signaling cascades, thus hampering downstream signal transduction. Here, we review and discuss current understanding of the evolutionary history and molecular mechanisms by which roles of host- and virus-encoded COPs and POPs may regulate inflammatory and immune responses. In addition, we address their (patho)physiological roles and highlight topics for further research.
Collapse
Affiliation(s)
- Magdalena Matusiak
- Department of Medical Protein Research, VIB, Ghent, Belgium; Department of Biochemistry, Ghent University, Ghent, Belgium
| | | | | |
Collapse
|
22
|
Abstract
Inflammasomes are protein complexes that promote the maturation and release of pro-inflammatory cytokines and danger signals as well as pyroptosis in response to infections and cellular stress. Inflammasomes consist of a sensor, an adapter, and the effector caspase-1, which interact through homotypic interactions of caspase recruitment domains (CARDs) or PYRIN domains (PYDs). Hence, decoy proteins encoding only a CARD or PYD, COPs and POPs, respectively, are assumed to inhibit inflammasome assembly. Sensors encoding a PYD belong to the families of NOD-like receptors containing a PYD (NLRPs) or AIM2-like receptors (ALRs), which interact with the PYD- and CARD-containing adapter ASC through homotypic PYD interactions. Subsequently, ASC undergoes PYD-dependent oligomerization, which promotes CARD-mediated interactions between ASC and caspase-1, resulting in caspase-1 activation. POPs are suggested to interfere with the interaction between NLRPs/ALRs and ASC to prevent nucleation of ASC and therefore prevent an oligomeric platform for caspase-1 activation. Similarly, COPs are suggested to bind to the CARD of caspase-1 to prevent its recruitment to the oligomeric ASC platform and its activation. Alternatively, the adapter ASC may regulate inflammasome activity by expressing different isoforms, which are either capable or incapable of assembling an oligomeric ASC platform. The molecular mechanism of inflammasome assembly has only recently been elucidated, but the effects of most COPs and POPs on inflammasome assembly have not been investigated. Here, we discuss our model of COP- and POP-mediated inflammasome regulation.
Collapse
Affiliation(s)
- Andrea Dorfleutner
- Division of Rheumatology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | | | | |
Collapse
|
23
|
Shimada K, Crother TR, Arditi M. POPsicle for Fever! Cooling Down the Inflammasome. Immunity 2015; 43:213-5. [PMID: 26287676 DOI: 10.1016/j.immuni.2015.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Inhibition of the inflammasome might be beneficial for numerous inflammatory pathologies. In this issue of Immunity, de Almeida et al. (2015) report that the PYRIN domain-only protein (POP1) efficiently inhibits inflammasome activation, identifying it as a pan-inflammasome inhibitor.
Collapse
Affiliation(s)
- Kenichi Shimada
- Departments of Biomedical Sciences and Pediatrics, Divisions of Infectious Diseases and Immunology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Infectious and Immunologic Diseases Research Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Timothy R Crother
- Departments of Biomedical Sciences and Pediatrics, Divisions of Infectious Diseases and Immunology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Infectious and Immunologic Diseases Research Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Moshe Arditi
- Departments of Biomedical Sciences and Pediatrics, Divisions of Infectious Diseases and Immunology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Infectious and Immunologic Diseases Research Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
| |
Collapse
|
24
|
Abstract
The PYRIN domain (PYD) is a protein-protein interaction domain, which belongs to the death domain fold (DDF) superfamily. It is best known for its signaling function in innate immune responses and particularly in the assembly of inflammasomes, which are large protein complexes that allow the induced proximity-mediated activation of caspase-1 and subsequently the release of pro-inflammatory cytokines. The molecular mechanism of inflammasome assembly was only recently elucidated and specifically requires PYD oligomerization. Here we discuss the recent advances in our understanding of PYD signaling and its regulation by PYD-only proteins.
Collapse
|
25
|
Jin T, Xiao TS. Activation and assembly of the inflammasomes through conserved protein domain families. Apoptosis 2015; 20:151-6. [PMID: 25398536 DOI: 10.1007/s10495-014-1053-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Inflammasomes are oligomeric protein complexes assembled through interactions among the death domain superfamily members, in particular the CARD and PYD domains. Recent progress has shed lights on how the ASC PYD can polymerize to form filaments using multiple domain:domain interfaces, and how the caspase4 CARD can recognize LPS to activate the non-classical inflammasome pathway. Comprehensive understanding of the molecular mechanisms of inflammasome activation and assembly require more extensive structural and biophysical dissection of the inflammasome components and complexes, in particular additional CARD or PYD filaments. Because of the variations in death domain structures and complexes observed so far, future work will undoubtedly shed lights on the mechanisms of inflammasome assembly as well as more surprises on the versatile structure and function of the death domain superfamily.
Collapse
Affiliation(s)
- Tengchuan Jin
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA,
| | | |
Collapse
|
26
|
Khan RN, Hay DP. A clear and present danger: inflammasomes DAMPing down disorders of pregnancy. Hum Reprod Update 2014; 21:388-405. [PMID: 25403436 DOI: 10.1093/humupd/dmu059] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 10/27/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND When the normal progression of pregnancy is threatened, inflammatory processes are often amplified in order to minimize detrimental effects and eliminate noxious agents. Inflammasomes are unique, intracellular, multiprotein assemblies that enable caspase-1 mediated proteolytic processing of the proinflammatory cytokine interleukin-1β, levels of which are elevated in some forms of preterm birth and maternal metabolic disorders. METHODS A comprehensive review based on a search of PubMed and Medline for terms and combinations of terms incorporating 'inflammation', 'inflammasome', 'pregnancy', 'preterm birth', 'pre-eclampsia', 'interleukin-1', 'caspase-1' and others selected to capture key articles. RESULTS In the decade since the discovery of the inflammasome, between January 2002 and June 2014 over 2200 articles have been published. Articles in the reproductive field are scarce but there is clear evidence for a role of the inflammasome axis in pregnancy, preterm birth and the maternal metabolic syndrome. CONCLUSION Further investigations on the inflammasome in pregnancy are needed in order to elucidate the biology of this unique structure in reproduction. Coordination of maternal, fetal and placental aspects of inflammasome function will potentially yield new information on the detection and transduction of host and non-host signals in the inflammatory response.
Collapse
Affiliation(s)
- Raheela N Khan
- Division of Medical Sciences & Graduate Entry Medicine, School of Medicine, University of Nottingham, Royal Derby Hospital Centre, Uttoxeter Road, Derby DE22 3DT, UK
| | - Daniel P Hay
- Division of Medical Sciences & Graduate Entry Medicine, School of Medicine, University of Nottingham, Royal Derby Hospital Centre, Uttoxeter Road, Derby DE22 3DT, UK
| |
Collapse
|
27
|
Porter KA, Duffy EB, Nyland P, Atianand MK, Sharifi H, Harton JA. The CLRX.1/NOD24 (NLRP2P) pseudogene codes a functional negative regulator of NF-κB, pyrin-only protein 4. Genes Immun 2014; 15:392-403. [PMID: 24871464 DOI: 10.1038/gene.2014.30] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 04/30/2014] [Accepted: 05/02/2014] [Indexed: 01/06/2023]
Abstract
Pseudogenes are duplicated yet defunct copies of functional parent genes. However, some pseudogenes have gained or retained function. In this study, we consider a functional role for the NLRP2-related, higher primate-specific, processed pseudogene NLRP2P, which is closely related to Pyrin-only protein 2 (POP2/PYDC2), a regulator of nuclear factor-κB (NF-κB) and the inflammasome. The NLRP2P open-reading frame on chromosome X has features consistent with a processed pseudogene (retrotransposon), yet encodes a 45-amino-acid, Pyrin-domain-related protein. The open-reading frame of NLRP2P shares 80% identity with POP2 and is under purifying selection across Old World primates. Although widely expressed, NLRP2P messenger RNA is upregulated by lipopolysaccharide in human monocytic cells. Functionally, NLRP2P impairs NF-κB p65 transactivation by reducing activating phosphorylation of RelA/p65. Reminiscent of POP2, NLRP2P reduces production of the NF-κB-dependent cytokines tumor necrosis factor alpha and interleukin (IL)-6 following toll-like receptor stimulation. In contrast to POP2, NLRP2P fails to inhibit the ASC-dependent NLRP3 inflammasome. In addition, beyond regulating cytokine production, NLRP2P has a potential role in cell cycle regulation and cell death. Collectively, our findings suggest that NLRP2P is a resurrected processed pseudogene that regulates NF-κB RelA/p65 activity and thus represents the newest member of the POP family, POP4.
Collapse
Affiliation(s)
- K A Porter
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY, USA
| | - E B Duffy
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY, USA
| | - P Nyland
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY, USA
| | - M K Atianand
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY, USA
| | - H Sharifi
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY, USA
| | - J A Harton
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY, USA
| |
Collapse
|
28
|
Le HT, Harton JA. Pyrin- and CARD-only Proteins as Regulators of NLR Functions. Front Immunol 2013; 4:275. [PMID: 24062743 PMCID: PMC3775265 DOI: 10.3389/fimmu.2013.00275] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 08/28/2013] [Indexed: 12/26/2022] Open
Abstract
Upon activation Nod-like receptors (NLRs) assemble into multi-protein complexes such as the NODosome and inflammasome. This process relies upon homo domain interactions between the structurally related Pyrin and caspase-recruitment (CARD) domains and adaptor proteins, such as ASC, or effector proteins, such as caspase-1. Although a variety of NLRP and NLRC complexes have been described along with their activating stimuli and associated proteins, less familiar are processes limiting assembly and/or promoting dissociation of NLR complexes. Given the importance of limiting harmful, chronic inflammation, such regulatory mechanisms are significant and likely numerous. Proteins comprised of a solitary Pyrin domain (Pyrin-only) or CARD domain (CARD-only) posses an obvious potential ability to act as competitive inhibitors of NLR complexes. Indeed, both Pyrin-only proteins (POPs) and CARD-only proteins (COPs) have been described as regulators of caspase-1 and/or NLR-inflammasome activation and not surprisingly as factors mediating pathogenesis. Although clear examples of pathogen encoded POPs are currently limited to members of the poxviridae, the human genome likely encodes three POPs (POP1, POP2, and a potential POP3), of which only POP2 is known to prevent NLR:ASC interaction, and three COPs (COP/Pseudo-ICE, INCA, and ICEBERG), initially described for their ability to inhibit caspase-1 activity. Surprisingly, among eukaryotic species POPs and COPs appear to be evolutionarily recent and restricted to higher primates, suggesting strong selective pressures driving their emergence. Despite the importance of understanding the regulation of NLR functions, relatively little attention has been devoted to revealing the biological impact of these intriguing proteins. This review highlights the current state of our understanding of POPs and COPs with attention to protein interaction, functions, evolution, implications for health and disease, and outstanding questions.
Collapse
Affiliation(s)
- Hongnga T Le
- Center for Immunology and Microbial Disease, Albany Medical College , Albany, NY , USA ; Department of Biochemistry, Faculty of Biology, University of Science, Vietnam National University-Ho Chi Minh City , Ho Chi Minh City , Vietnam
| | | |
Collapse
|
29
|
Damm A, Lautz K, Kufer TA. Roles of NLRP10 in innate and adaptive immunity. Microbes Infect 2013; 15:516-23. [DOI: 10.1016/j.micinf.2013.03.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 03/22/2013] [Indexed: 12/19/2022]
|