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Glitsch MD. Recent advances in acid sensing by G protein coupled receptors. Pflugers Arch 2024; 476:445-455. [PMID: 38340167 PMCID: PMC11006784 DOI: 10.1007/s00424-024-02919-y] [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: 12/01/2023] [Revised: 01/30/2024] [Accepted: 01/30/2024] [Indexed: 02/12/2024]
Abstract
Changes in extracellular proton concentrations occur in a variety of tissues over a range of timescales under physiological conditions and also accompany virtually all pathologies, notably cancers, stroke, inflammation and trauma. Proton-activated, G protein coupled receptors are already partially active at physiological extracellular proton concentrations and their activity increases with rising proton concentrations. Their ability to monitor and report changes in extracellular proton concentrations and hence extracellular pH appears to be involved in a variety of processes, and it is likely to mirror and in some cases promote disease progression. Unsurprisingly, therefore, these pH-sensing receptors (pHR) receive increasing attention from researchers working in an expanding range of research areas, from cellular neurophysiology to systemic inflammatory processes. This review is looking at progress made in the field of pHRs over the past few years and also highlights outstanding issues.
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Affiliation(s)
- Maike D Glitsch
- Medical School Hamburg, Am Sandtorkai 1, 20457, Hamburg, Germany.
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2
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Lunjani N, Ambikan AT, Hlela C, Levin M, Mankahla A, Heldstab‐Kast JI, Boonpiyathad T, Tan G, Altunbulakli C, Gray C, Nadeau KC, Neogi U, Akdis CA, O'Mahony L. Rural and urban exposures shape early life immune development in South African children with atopic dermatitis and nonallergic children. Allergy 2024; 79:65-79. [PMID: 37534631 PMCID: PMC10952395 DOI: 10.1111/all.15832] [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: 05/21/2023] [Revised: 07/01/2023] [Accepted: 07/04/2023] [Indexed: 08/04/2023]
Abstract
BACKGROUND Immunological traits and functions have been consistently associated with environmental exposures and are thought to shape allergic disease susceptibility and protection. In particular, specific exposures in early life may have more significant effects on the developing immune system, with potentially long-term impacts. METHODS We performed RNA-Seq on peripheral blood mononuclear cells (PBMCs) from 150 children with atopic dermatitis and healthy nonallergic children in rural and urban settings from the same ethnolinguistic AmaXhosa background in South Africa. We measured environmental exposures using questionnaires. RESULTS A distinct PBMC gene expression pattern was observed in those children with atopic dermatitis (132 differentially expressed genes [DEGs]). However, the predominant influences on the immune cell transcriptome were related to early life exposures including animals, time outdoors, and types of cooking and heating fuels. Sample clustering revealed two rural groups (Rural_1 and Rural_2) that separated from the urban group (3413 and 2647 DEGs, respectively). The most significantly regulated pathways in Rural_1 children were related to innate activation of the immune system (e.g., TLR and cytokine signaling), changes in lymphocyte polarization (e.g., TH17 cells), and immune cell metabolism (i.e., oxidative phosphorylation). The Rural_2 group displayed evidence for ongoing lymphocyte activation (e.g., T cell receptor signaling), with changes in immune cell survival and proliferation (e.g., mTOR signaling, insulin signaling). CONCLUSIONS This study highlights the importance of the exposome on immune development in early life and identifies potentially protective (e.g., animal) exposures and potentially detrimental (e.g., pollutant) exposures that impact key immunological pathways.
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Affiliation(s)
- Nonhlanhla Lunjani
- Division of DermatologyUniversity of Cape TownCape TownSouth Africa
- APC Microbiome IrelandUniversity College CorkCorkIreland
| | - Anoop T. Ambikan
- The Systems Virology Lab, Division of Clinical Microbiology, Department of Laboratory MedicineKarolinska Institute, ANA FuturaStockholmSweden
| | - Carol Hlela
- Division of DermatologyUniversity of Cape TownCape TownSouth Africa
| | - Michael Levin
- Division of Paediatric Allergy, Department of Paediatrics and Child HealthUniversity of Cape TownCape TownSouth Africa
| | - Avumile Mankahla
- The Division of Dermatology, Department of Medicine and PharmacologyWalter Sisulu UniversityMthathaEastern CapeSouth Africa
| | | | - Tadech Boonpiyathad
- Swiss Institute of Allergy and Asthma Research (SIAF), University of ZurichDavosSwitzerland
| | - Ge Tan
- Swiss Institute of Allergy and Asthma Research (SIAF), University of ZurichDavosSwitzerland
| | - Can Altunbulakli
- Swiss Institute of Allergy and Asthma Research (SIAF), University of ZurichDavosSwitzerland
| | - Clive Gray
- Division of ImmunologyUniversity of Cape TownCape TownSouth Africa
| | - Kari C. Nadeau
- Department of Environmental HealthHarvard T.H. Chan School of Public HealthBostonMAUSA
| | - Ujjwal Neogi
- The Systems Virology Lab, Division of Clinical Microbiology, Department of Laboratory MedicineKarolinska Institute, ANA FuturaStockholmSweden
| | - Cezmi A. Akdis
- Swiss Institute of Allergy and Asthma Research (SIAF), University of ZurichDavosSwitzerland
- Christine Kühne‐Center for Allergy Research and EducationDavosSwitzerland
| | - Liam O'Mahony
- APC Microbiome IrelandUniversity College CorkCorkIreland
- Department of MedicineUniversity College CorkCorkIreland
- School of MicrobiologyUniversity College CorkCorkIreland
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3
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Hajjar S, Zhou X. pH sensing at the intersection of tissue homeostasis and inflammation. Trends Immunol 2023; 44:807-825. [PMID: 37714775 PMCID: PMC10543622 DOI: 10.1016/j.it.2023.08.008] [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: 08/08/2023] [Revised: 08/13/2023] [Accepted: 08/13/2023] [Indexed: 09/17/2023]
Abstract
pH is tightly maintained at cellular, tissue, and systemic levels, and altered pH - particularly in the acidic range - is associated with infection, injury, solid tumors, and physiological and pathological inflammation. However, how pH is sensed and regulated and how it influences immune responses remain poorly understood at the tissue level. Applying conceptual frameworks of homeostatic and inflammatory circuitries, we categorize cellular and tissue components engaged in pH regulation, drawing parallels from established cases in physiology. By expressing various intracellular (pHi) and extracellular pH (pHe)-sensing receptors, the immune system may integrate information on tissue and cellular states into the regulation of homeostatic and inflammatory programs. We introduce the novel concept of resistance and adaptation responses to rationalize pH-dependent immunomodulation intertwined with homeostatic equilibrium and inflammatory control. We discuss emerging challenges and opportunities in understanding the immunological roles of pH sensing, which might reveal new strategies to combat inflammation and restore tissue homeostasis.
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Affiliation(s)
- Stephanie Hajjar
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, 300 Longwood Ave, Boston, MA 02115, USA
| | - Xu Zhou
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, 300 Longwood Ave, Boston, MA 02115, USA.
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4
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de Souza Ferreira S, Bek MK, Tibbitt CA. pH sensing shapes immune cell function: The role of GPR65 and its implications for allergic disease. Allergy 2023. [PMID: 36916643 DOI: 10.1111/all.15708] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/17/2023] [Accepted: 03/09/2023] [Indexed: 03/15/2023]
Affiliation(s)
- Sabrina de Souza Ferreira
- Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
- Clinical Lung and Allergy Research, Medical Unit for Lung and Allergy Diseases, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Marie Kaarup Bek
- Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
- Clinical Lung and Allergy Research, Medical Unit for Lung and Allergy Diseases, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Christopher Andrew Tibbitt
- Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
- Clinical Lung and Allergy Research, Medical Unit for Lung and Allergy Diseases, Karolinska University Hospital Huddinge, Stockholm, Sweden
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Abstract
Atopic dermatitis (AD) is a chronic, relapsing, and extremely pruritic inflammatory skin disease with a particular impact on children. AD pathogenesis is not yet fully understood, and there is no curative treatment for this disease. Therefore, several genetically or chemically-induced AD mouse models have been developed. These preclinical mouse models are an indispensable research tool for studying AD pathogenesis and evaluating the efficacy of new candidate AD therapeutics. A commonly used mouse model of AD has been developed using the topical application of a low-calcemic analog of vitamin D3, MC903, to induce AD-like inflammatory phenotypes that closely resemble human AD. Moreover, this model shows a minimal effect on systemic calcium metabolism that is observed in the vitamin D3-induced AD model. Thus, an expanding number of studies use the MC903-induced AD model to interrogate AD pathobiology in vivo and to test new candidate small molecule and monoclonal antibody therapies. This protocol describes in detail functional measurements including the measurement of skin thickness, which is a surrogate marker for ear skin inflammation, as well as itch assessment, histological evaluation to assess the structural changes associated with AD skin inflammation, and preparation of single-cell suspensions from ear skin and draining lymph nodes for the assessment of inflammatory leukocyte subset infiltration in these tissues using flow cytometry. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Topical application of MC903 induces AD-like skin inflammation Support Protocol 1: Measurement of ear skin thickness Support Protocol 2: Itch assessment Support Protocol 3: Dissection of ear skin and ear draining lymph nodes Support Protocol 4: Histological evaluation and quantification Support Protocol 5: Preparation of single-cell suspension from ear skin and draining lymph nodes for the assessment of inflammatory immune cell infiltration using flow cytometry.
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Affiliation(s)
- Md Jahangir Alam
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Liang Xie
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Yu-Anne Yap
- Department of Physiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Remy Robert
- Department of Physiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
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Araviiskaia E, Pincelli C, Sparavigna A, Luger T. The Role of a Novel Generation of Emollients, 'Emollients Plus', in Atopic Dermatitis. Clin Cosmet Investig Dermatol 2022; 15:2705-2719. [PMID: 36545500 PMCID: PMC9763050 DOI: 10.2147/ccid.s389697] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/26/2022] [Indexed: 12/15/2022]
Abstract
Emollients are the mainstay maintenance treatment for atopic dermatitis (AD). A novel generation of emollients, 'emollients plus', containing active, non-medicated substances, has softened the distinction between emollients and topical drugs. A literature search for selected key words was performed using PubMed. Additional papers were identified based on author expertise. Whilst the inclusion of five components of an ideal emollient has been proposed, no such consensus exists for emollients plus and they can vary markedly in their composition and modes of action for AD treatment. This could have a profound effect on their clinical efficacy. The efficacy of emollients plus in restoring and maintaining skin barrier function has been demonstrated on multiple levels, with evidence reported for their effects on the physical and biochemical, microbial, immunological, and neurosensory barriers. When selecting an appropriate AD treatment approach, the safety profiles of the available topical therapies must be carefully considered. There are several proposed treatment approaches for AD, including preventive, proactive, intermittent, and synergistic approaches. Emollients plus may be effective not only as maintenance therapy for AD, but also when used synergistically with anti-inflammatory pharmacological therapies.
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Affiliation(s)
- Elena Araviiskaia
- Department of Dermatology and Venereal Diseases, First Pavlov State Medical University of St Petersburg, St Petersburg, Russia
| | - Carlo Pincelli
- DermoLab, Department of Surgical, Medical, Dental and Morphological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Adele Sparavigna
- Derming Clinical Research and Bioengineering Institute, Milan, Italy
| | - Thomas Luger
- Department of Dermatology, University of Munster, Munster, Germany,Correspondence: Thomas Luger, Dermatology Clinic, University of Münster, Von-Esmarch-Straẞe 58, Münster, 48149, Germany, Email
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7
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Resolution of Eczema with Multivalent Peptides. JID INNOVATIONS 2022; 2:100142. [PMID: 36039327 PMCID: PMC9418603 DOI: 10.1016/j.xjidi.2022.100142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 11/24/2022] Open
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8
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Chen X, Jaiswal A, Costliow Z, Herbst P, Creasey EA, Oshiro-Rapley N, Daly MJ, Carey KL, Graham DB, Xavier RJ. pH sensing controls tissue inflammation by modulating cellular metabolism and endo-lysosomal function of immune cells. Nat Immunol 2022; 23:1063-1075. [PMID: 35668320 PMCID: PMC9720675 DOI: 10.1038/s41590-022-01231-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 04/26/2022] [Indexed: 02/08/2023]
Abstract
Extracellular acidification occurs in inflamed tissue and the tumor microenvironment; however, a systematic study on how pH sensing contributes to tissue homeostasis is lacking. In the present study, we examine cell type-specific roles of the pH sensor G protein-coupled receptor 65 (GPR65) and its inflammatory disease-associated Ile231Leu-coding variant in inflammation control. GPR65 Ile231Leu knock-in mice are highly susceptible to both bacterial infection-induced and T cell-driven colitis. Mechanistically, GPR65 Ile231Leu elicits a cytokine imbalance through impaired helper type 17 T cell (TH17 cell) and TH22 cell differentiation and interleukin (IL)-22 production in association with altered cellular metabolism controlled through the cAMP-CREB-DGAT1 axis. In dendritic cells, GPR65 Ile231Leu elevates IL-12 and IL-23 release at acidic pH and alters endo-lysosomal fusion and degradation capacity, resulting in enhanced antigen presentation. The present study highlights GPR65 Ile231Leu as a multistep risk factor in intestinal inflammation and illuminates a mechanism by which pH sensing controls inflammatory circuits and tissue homeostasis.
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Affiliation(s)
- Xiangjun Chen
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
- Experimental Medicine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Alok Jaiswal
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | - Paula Herbst
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
| | - Elizabeth A Creasey
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
| | - Noriko Oshiro-Rapley
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
- Experimental Medicine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Mark J Daly
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Institute for Molecular Medicine Finland, Helsinki, Finland
| | | | - Daniel B Graham
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
- Experimental Medicine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Ramnik J Xavier
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, USA.
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA.
- Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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9
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Imenez Silva PH, Câmara NO, Wagner CA. Role of proton-activated G protein-coupled receptors in pathophysiology. Am J Physiol Cell Physiol 2022; 323:C400-C414. [PMID: 35759438 DOI: 10.1152/ajpcell.00114.2022] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Local acidification is a common feature of many disease processes such as inflammation, infarction, or solid tumor growth. Acidic pH is not merely a sequelae of disease but contributes to recruitment and regulation of immune cells, modifies metabolism of parenchymal, immune and tumor cells, modulates fibrosis, vascular permeability, oxygen availability and consumption, invasiveness of tumor cells, and impacts on cell survival. Thus, multiple pH-sensing mechanisms must exist in cells involved in these processes. These pH-sensors play important roles in normal physiology and pathophysiology, and hence might be attractive targets for pharmacological interventions. Among the pH-sensing mechanisms, OGR1 (GPR68), GPR4 (GPR4), and TDAG8 (GPR65) have emerged as important molecules. These G protein-coupled receptors are widely expressed, are upregulated in inflammation and tumors, sense changes in extracellular pH in the range between pH 8 and 6, and are involved in modulating key processes in inflammation, tumor biology, and fibrosis. This review discusses key features of these receptors and highlights important disease states and pathways affected by their activity.
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Affiliation(s)
- Pedro H Imenez Silva
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Switzerland
| | - Niels Olsen Câmara
- Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Switzerland
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10
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Manipulating Microbiota to Treat Atopic Dermatitis: Functions and Therapies. Pathogens 2022; 11:pathogens11060642. [PMID: 35745496 PMCID: PMC9228373 DOI: 10.3390/pathogens11060642] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 05/27/2022] [Accepted: 05/29/2022] [Indexed: 12/13/2022] Open
Abstract
Atopic dermatitis (AD) is a globally prevalent skin inflammation with a particular impact on children. Current therapies for AD are challenged by the limited armamentarium and the high heterogeneity of the disease. A novel promising therapeutic target for AD is the microbiota. Numerous studies have highlighted the involvement of the skin and gut microbiota in the pathogenesis of AD. The resident microbiota at these two epithelial tissues can modulate skin barrier functions and host immune responses, thus regulating AD progression. For example, the pathogenic roles of Staphylococcus aureus in the skin are well-established, making this bacterium an attractive target for AD treatment. Targeting the gut microbiota is another therapeutic strategy for AD. Multiple oral supplements with prebiotics, probiotics, postbiotics, and synbiotics have demonstrated promising efficacy in both AD prevention and treatment. In this review, we summarize the association of microbiota dysbiosis in both the skin and gut with AD, and the current knowledge of the functions of commensal microbiota in AD pathogenesis. Furthermore, we discuss the existing therapies in manipulating both the skin and gut commensal microbiota to prevent or treat AD. We also propose potential novel therapies based on the cutting-edge progress in this area.
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Lin R, Wu W, Chen H, Gao H, Wu X, Li G, He Q, Lu H, Sun M, Liu Z. GPR65 promotes intestinal mucosal Th1 and Th17 cell differentiation and gut inflammation through downregulating NUAK2. Clin Transl Med 2022; 12:e771. [PMID: 35343079 PMCID: PMC8958354 DOI: 10.1002/ctm2.771] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 02/27/2022] [Accepted: 03/02/2022] [Indexed: 01/15/2023] Open
Abstract
G protein-coupled receptor 65 (GPR65), a susceptibility gene for inflammatory bowel diseases (IBD), has been identified to promote Th17 cell pathogenicity and induce T cell apoptosis. However, the potential role of GPR65 in modulating CD4+ T cell immune responses in the pathogenesis of IBD stills not entirely understood. Here, we displayed that GPR65 expression was increased in inflamed intestinal mucosa of IBD patients and positively associated with disease activity. It was expressed in CD4+ T cells and robustly upregulated through the TNF-α-caspase 3/8 signalling pathway. Ectopic expression of GPR65 significantly promoted the differentiation of peripheral blood (PB) CD4+ T cells from IBD patients and HC to Th1 and Th17 cells in vitro. Importantly, conditional knockout of Gpr65 in CD4+ T cells ameliorated trinitrobenzene sulfonic acid (TNBS)-induced acute murine colitis and a chronic colitis in Rag1-/- mice reconstituted with CD45RBhigh CD4+ T cells in vivo, characterised by attenuated Th1 and Th17 cell immune response in colon mucosa and decreased infiltration of CD4+ T cells, neutrophils and macrophages. RNA-seq analysis of Gpr65ΔCD4 and Gpr65flx/flx CD4+ T cells revealed that NUAK family kinase 2 (Nuak2) acts as a functional target of Gpr65 to restrict Th1 and Th17 cell immune response. Mechanistically, GPR65 deficiency promoted NUAK2 expression via the cAMP-PKA-C-Raf-ERK1/2-LKB1-mediated signalling pathway. Consistently, silencing of Nuak2 facilitated the differentiation of Gpr65ΔCD4 and Gpr65flx/flx CD4+ T cells into Th1 and Th17 cells. Therefore, our data point out that GPR65 promotes Th1 and Th17 cell immune response and intestinal mucosal inflammation by suppressing NUAK2 expression, and that targeting GPR65 and NUAK2 in CD4+ T cells may represent a novel therapeutic approach for IBD.
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Affiliation(s)
- Ritian Lin
- Center for Inflammatory Bowel Disease ResearchThe Shanghai Tenth People's HospitalTongji University of School MedicineShanghaiChina
| | - Wei Wu
- Center for Inflammatory Bowel Disease ResearchThe Shanghai Tenth People's HospitalTongji University of School MedicineShanghaiChina
| | - Huimin Chen
- Center for Inflammatory Bowel Disease ResearchThe Shanghai Tenth People's HospitalTongji University of School MedicineShanghaiChina
| | - Han Gao
- Center for Inflammatory Bowel Disease ResearchThe Shanghai Tenth People's HospitalTongji University of School MedicineShanghaiChina
| | - Xiaohan Wu
- Center for Inflammatory Bowel Disease ResearchThe Shanghai Tenth People's HospitalTongji University of School MedicineShanghaiChina
| | - Gengfeng Li
- Center for Inflammatory Bowel Disease ResearchThe Shanghai Tenth People's HospitalTongji University of School MedicineShanghaiChina
| | - Qiong He
- Center for Inflammatory Bowel Disease ResearchThe Shanghai Tenth People's HospitalTongji University of School MedicineShanghaiChina
| | - Huiying Lu
- Center for Inflammatory Bowel Disease ResearchThe Shanghai Tenth People's HospitalTongji University of School MedicineShanghaiChina
| | - Mingming Sun
- Center for Inflammatory Bowel Disease ResearchThe Shanghai Tenth People's HospitalTongji University of School MedicineShanghaiChina
| | - Zhanju Liu
- Center for Inflammatory Bowel Disease ResearchThe Shanghai Tenth People's HospitalTongji University of School MedicineShanghaiChina
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12
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IBD-associated G protein-coupled receptor 65 variant compromises signalling and impairs key functions involved in inflammation. Cell Signal 2022; 93:110294. [PMID: 35218908 PMCID: PMC9536022 DOI: 10.1016/j.cellsig.2022.110294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 02/06/2022] [Accepted: 02/21/2022] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND AIMS Inflammatory bowel diseases (IBD) result in chronic inflammation of the gastrointestinal tract. Genetic studies have shown that the GPR65 gene, as well as its missense coding variant, GPR65*Ile231Leu, is associated with IBD. We aimed to define the signalling and biological pathways downstream of GPR65 activation and evaluate the impact of GPR65*231Leu on these. METHODS We used HEK 293 cells stably expressing GPR65 and deficient for either Gαs, Gαq/11 or Gα12/13, to define GPR65 signalling pathways, IBD patient biopsies and a panel of human tissues, primary immune cells and cell lines to determine biologic context, and genetic modulation of human THP-1-derived macrophages to examine the impact of GPR65 in bacterial phagocytosis and NLRP3 inflammasome activation. RESULTS We confirmed that GPR65 signals via the Gαs pathway, leading to cAMP accumulation. GPR65 can also signal via the Gα12/13 pathway leading to formation of stress fibers, actin remodeling and RhoA activation; all impaired by the IBD-associated GPR65*231Leu allele. Gene expression profiling revealed greater expression of GPR65 in biopsies from inflamed compared to non-inflamed tissues from IBD patients or control individuals, potentially explained by infiltration of inflammatory immune cells. Decreased GPR65 expression in THP-1-derived macrophages leads to impaired bacterial phagocytosis, increased NLRP3 inflammasome activation and IL-1β secretion in response to an inflammatory stimulus. CONCLUSIONS We demonstrate that GPR65 exerts its effects through Gαs- and Gα12/13-mediated pathways, that the IBD-associated GPR65*231Leu allele has compromised interactions with Gα12/13 and that KD of GPR65 leads to impaired bacterial phagocytosis and increased inflammatory signalling via the NLRP3 inflammasome. This work identifies a target for development of small molecule therapies.
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