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Kong L, Fang Y, Du M, Wang Y, He H, Liu Z. Gαi2 regulates the adult myogenesis of masticatory muscle satellite cells. J Cell Mol Med 2023; 27:1239-1249. [PMID: 36977201 PMCID: PMC10148056 DOI: 10.1111/jcmm.17726] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/22/2023] [Accepted: 03/08/2023] [Indexed: 03/30/2023] Open
Abstract
Although similar to trunk and limb skeletal muscles, masticatory muscles are believed as unique in both developmental origins and myogenesis. Gαi2 has been demonstrated to promote muscle hypertrophy and muscle satellite cell differentiation in limb muscles. However, the effect of Gαi2 on masticatory muscles is still unexplored. This study aimed to identify the role of Gαi2 in the proliferation and differentiation of masticatory muscle satellite cells, further exploring the metabolic mechanism of masticatory muscles. The proliferation rate, myotube size, fusion index of masticatory muscle satellite cells and Pax7, Myf5, MyoD, Tcf21 and Musculin expressions were significantly decreased by Gαi2 knockdown, while in cells infected with AdV4-Gαi2, the proliferation rate, myotube size, fusion index and Tbx1 expression were significantly increased. Masticatory muscle satellite cells also displayed phenotype transformation as Gαi2 changed. In addition, Gαi2 altered myosin heavy chain (MyHC) isoforms of myotubes with less MyHC-2A expression in siGαi2 group and more MyHC-slow expression in AdV4-Gαi2 group. In conclusion, Gαi2 could positively affect the adult myogenesis of masticatory muscle satellite cells and maintain the superiority of MyHC-slow. Masticatory muscle satellite cells may have their unique Gαi2-regulated myogenic transcriptional networks, although they may share some common characteristics with trunk and limb muscles.
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Affiliation(s)
- Lin Kong
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Yi Fang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
- Kunming Medical University School and Hospital of Stomatology, Kunming, China
- Yunnan Key Laboratory of Stomatology, Kunming, China
| | - Mingyuan Du
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
- Department of Orthodontics, School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Yunlong Wang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
- Department of Orthodontics, School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Hong He
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
- Department of Orthodontics, School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Zhijian Liu
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
- Department of Orthodontics, School and Hospital of Stomatology, Wuhan University, Wuhan, China
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2
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Multi-Cell-Type Openness-Weighted Association Studies for Trait-Associated Genomic Segments Prioritization. Genes (Basel) 2022; 13:genes13071220. [PMID: 35886003 PMCID: PMC9323627 DOI: 10.3390/genes13071220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 06/30/2022] [Accepted: 07/03/2022] [Indexed: 02/01/2023] Open
Abstract
Openness-weighted association study (OWAS) is a method that leverages the in silico prediction of chromatin accessibility to prioritize genome-wide association studies (GWAS) signals, and can provide novel insights into the roles of non-coding variants in complex diseases. A prerequisite to apply OWAS is to choose a trait-related cell type beforehand. However, for most complex traits, the trait-relevant cell types remain elusive. In addition, many complex traits involve multiple related cell types. To address these issues, we develop OWAS-joint, an efficient framework that aggregates predicted chromatin accessibility across multiple cell types, to prioritize disease-associated genomic segments. In simulation studies, we demonstrate that OWAS-joint achieves a greater statistical power compared to OWAS. Moreover, the heritability explained by OWAS-joint segments is higher than or comparable to OWAS segments. OWAS-joint segments also have high replication rates in independent replication cohorts. Applying the method to six complex human traits, we demonstrate the advantages of OWAS-joint over a single-cell-type OWAS approach. We highlight that OWAS-joint enhances the biological interpretation of disease mechanisms, especially for non-coding regions.
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Miete C, Solis GP, Koval A, Brückner M, Katanaev VL, Behrens J, Bernkopf DB. Gαi2-induced conductin/axin2 condensates inhibit Wnt/β-catenin signaling and suppress cancer growth. Nat Commun 2022; 13:674. [PMID: 35115535 PMCID: PMC8814139 DOI: 10.1038/s41467-022-28286-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 01/14/2022] [Indexed: 12/25/2022] Open
Abstract
Conductin/axin2 is a scaffold protein negatively regulating the pro-proliferative Wnt/β-catenin signaling pathway. Accumulation of scaffold proteins in condensates frequently increases their activity, but whether condensation contributes to Wnt pathway inhibition by conductin remains unclear. Here, we show that the Gαi2 subunit of trimeric G-proteins induces conductin condensation by targeting a polymerization-inhibiting aggregon in its RGS domain, thereby promoting conductin-mediated β-catenin degradation. Consistently, transient Gαi2 expression inhibited, whereas knockdown activated Wnt signaling via conductin. Colorectal cancers appear to evade Gαi2-induced Wnt pathway suppression by decreased Gαi2 expression and inactivating mutations, associated with shorter patient survival. Notably, the Gαi2-activating drug guanabenz inhibited Wnt signaling via conductin, consequently reducing colorectal cancer growth in vitro and in mouse models. In summary, we demonstrate Wnt pathway inhibition via Gαi2-triggered conductin condensation, suggesting a tumor suppressor function for Gαi2 in colorectal cancer, and pointing to the FDA-approved drug guanabenz for targeted cancer therapy.
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Affiliation(s)
- Cezanne Miete
- Experimental Medicine II, Nikolaus-Fiebiger-Center, Friedrich-Alexander University Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Gonzalo P Solis
- Department of Cell Physiology and Metabolism, Centre Médical Universitaire, University of Geneva, 1211, Geneva 4, Geneva, Switzerland
| | - Alexey Koval
- Department of Cell Physiology and Metabolism, Centre Médical Universitaire, University of Geneva, 1211, Geneva 4, Geneva, Switzerland
| | - Martina Brückner
- Experimental Medicine II, Nikolaus-Fiebiger-Center, Friedrich-Alexander University Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Vladimir L Katanaev
- Department of Cell Physiology and Metabolism, Centre Médical Universitaire, University of Geneva, 1211, Geneva 4, Geneva, Switzerland
- School of Biomedicine, Far Eastern Federal University, 690922, Vladivostok, Russia
| | - Jürgen Behrens
- Experimental Medicine II, Nikolaus-Fiebiger-Center, Friedrich-Alexander University Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Dominic B Bernkopf
- Experimental Medicine II, Nikolaus-Fiebiger-Center, Friedrich-Alexander University Erlangen-Nürnberg, 91054, Erlangen, Germany.
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Leiss V, Reisinger E, Speidel A, Beer-Hammer S, Nürnberg B. Analyses of Gnai3-iresGFP reporter mice reveal unknown Gα i3 expression sites. Sci Rep 2021; 11:14271. [PMID: 34253772 PMCID: PMC8275620 DOI: 10.1038/s41598-021-93591-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/21/2021] [Indexed: 12/01/2022] Open
Abstract
Inhibitory G proteins (Gi proteins) are highly homologous but play distinct biological roles. However, their isoform-specific detection remains challenging. To facilitate the analysis of Gαi3 expression, we generated a Gnai3- iresGFP reporter mouse line. An internal ribosomal entry site (IRES) was inserted behind the stop-codon of the Gnai3 gene to initiate simultaneous translation of the GFP cDNA together with Gαi3. The expression of GFP was confirmed in spleen and thymus tissue by immunoblot analysis. Importantly, the GFP knock-in (ki) did not alter Gαi3 expression levels in all organs tested including spleen and thymus compared to wild-type littermates. Flow cytometry of thymocytes, splenic and blood cell suspensions revealed significantly higher GFP fluorescence intensities in homozygous ki/ki animals compared to heterozygous mice (+/ki). Using cell-type specific surface markers GFP fluorescence was assigned to B cells, T cells, macrophages and granulocytes from both splenic and blood cells and additionally blood-derived platelets. Moreover, immunofluorescent staining of the inner ear from knock-in mice unraveled GFP expression in sensory and non-sensory cell types, with highest levels in Deiter’s cells and in the first row of Hensen’s cells in the organ of Corti, indicating a novel site for Gαi3 expression. In summary, the Gnai3- iresGFP reporter mouse represents an ideal tool for precise analyses of Gαi3 expression patterns and sites.
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Affiliation(s)
- Veronika Leiss
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, and ICePhA Mouse Clinic, University of Tübingen, Wilhelmstraße 56, 72074, Tübingen, Germany
| | - Ellen Reisinger
- Department of Otolaryngology-Head and Neck Surgery, Gene Therapy for Hearing Impairment Group, University of Tübingen, Medical Center, Elfriede-Aulhorn-Straße 5, 72076, Tübingen, Germany
| | - Annika Speidel
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, and ICePhA Mouse Clinic, University of Tübingen, Wilhelmstraße 56, 72074, Tübingen, Germany
| | - Sandra Beer-Hammer
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, and ICePhA Mouse Clinic, University of Tübingen, Wilhelmstraße 56, 72074, Tübingen, Germany.
| | - Bernd Nürnberg
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, and ICePhA Mouse Clinic, University of Tübingen, Wilhelmstraße 56, 72074, Tübingen, Germany
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Short-chain free-fatty acid G protein-coupled receptors in colon cancer. Biochem Pharmacol 2021; 186:114483. [PMID: 33631190 DOI: 10.1016/j.bcp.2021.114483] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/12/2021] [Accepted: 02/16/2021] [Indexed: 12/31/2022]
Abstract
The dietary role of macronutrients and their metabolites in cancer has been evident for many decades. Dietary ingestion of fat, carbohydrates, protein, and fiber, as well as probiotics that influence gut microbiota, have all been linked to gastrointestinal (GI) tract health and disease, particularly in the colon, where it has long been known that fat and fiber can regulate inflammation and carcinogenesis. Short-chained fatty acids (SCFA), including acetate, propionate, and butyrate, which are biosynthesized by microbiota-mediated metabolism of dietary fiber, have previously been shown to play important roles in colorectal health, including decreasing inflammation and oxidative stress. Since the 1980s, a growing number of studies have also demonstrated a link between SCFA and colon epithelial cell carcinogenesis and prevention of colorectal cancers (CRC). While the effects of SCFA have historically been associated with their intracellular metabolism and function, the discovery of a family of G protein-coupled free-fatty acid receptors in the early 2000s suggests that many effects of SCFA are cell-surface receptor mediated. Indeed, the SCFA GPCRs FFA2 (previously termed GPR43), FFA3 (previously termed GPR41), and GPR109A are now well established to be expressed within the GI tract, where they modulate a variety of functions in response to luminal SCFA. While the role of SCFA in cancers, including CRC, has been reviewed in detail elsewhere, the goal of this report is to provide a review on the current body of evidence in regard to the effects of SCFA on FFA2, FFA3, and GPR109A in colon cancers.
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Leiss V, Schönsiegel A, Gnad T, Kerner J, Kaur J, Sartorius T, Machann J, Schick F, Birnbaumer L, Häring HU, Pfeifer A, Nürnberg B. Lack of Gα i2 proteins in adipocytes attenuates diet-induced obesity. Mol Metab 2020; 40:101029. [PMID: 32480042 PMCID: PMC7306590 DOI: 10.1016/j.molmet.2020.101029] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVES Typically, obesity results from an inappropriate balance between energy uptake from nutrient consumption and burning of calories, which leads to a pathological increase in fat mass. Obesity is a major cause of insulin resistance and diabetes. Inhibitory G proteins (Gαi) form a subfamily that is involved in the regulation of adipose tissue function. Among the three Gαi members, i.e. Gαi1, Gαi2, Gαi3, the Gαi2, protein is predominantly expressed in adipose tissue. However, the functions of the Gαi2 isoform in adipose tissue and its impact on the development of obesity are poorly understood. METHODS By using AdipoqCreERT2 mice, we generated adipocyte-specific Gnai2-deficient mice to study Gαi2 function, specifically in white and brown adipocytes. These mice were fed either a control diet (CD) or a high fat diet (HFD). Mice were examined for obesity development, insulin resistance and glucose intolerance. We examined adipocyte morphology and the development of inflammation in the white adipose tissue. Finally, intracellular cAMP levels as an indicator of Gαi signaling and glycerol release as an indicator of lipolysis rates were measured to verify the impact of Gαi2 on the signaling pathway in brown and white adipocytes. RESULTS An adipocyte-specific deficiency of Gαi2 significantly reduced diet-induced obesity, leading to decreased fat masses, smaller adipocytes and decreased inflammation in the white adipose tissue relative to littermate controls. Concurrently, oxygen consumption of brown adipocytes and in vivo measured energy expenditure were significantly enhanced. In addition, glucose tolerance and insulin sensitivity of HFD-fed adipocyte-specific Gnai2-deficient mice were improved compared to the respective controls. In the absence of Gαi2, adrenergic stimulation of intracellular adipocyte cAMP levels was increased, which correlated with increased lipolysis and energy expenditure. CONCLUSION We conclude that adipocyte Gαi2 is a major regulator of adipocyte lipid content in diet-induced obesity by inhibiting adipocyte lipolysis in a cAMP-dependent manner resulting in increased energy expenditure.
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MESH Headings
- Adipocytes, Brown/metabolism
- Adipocytes, White/metabolism
- Adipose Tissue/metabolism
- Adipose Tissue/physiology
- Adipose Tissue, Brown/metabolism
- Adipose Tissue, White/metabolism
- Animals
- Diet, High-Fat
- Energy Metabolism
- GTP-Binding Protein alpha Subunit, Gi2/metabolism
- GTP-Binding Protein alpha Subunit, Gi2/physiology
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- GTP-Binding Protein alpha Subunits, Gi-Go/physiology
- Glucose/metabolism
- Glucose Intolerance/metabolism
- Insulin/metabolism
- Insulin Resistance/physiology
- Lipolysis
- Male
- Mice
- Mice, Inbred C57BL
- Obesity/genetics
- Obesity/metabolism
- Oxygen Consumption
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Affiliation(s)
- Veronika Leiss
- Department of Pharmacology, Experimental Therapy and Toxicology and Interfaculty Center of Pharmacoge-nomics and Drug Research, University of Tübingen, 72074, Tübingen, Germany
| | - Annika Schönsiegel
- Department of Pharmacology, Experimental Therapy and Toxicology and Interfaculty Center of Pharmacoge-nomics and Drug Research, University of Tübingen, 72074, Tübingen, Germany
| | - Thorsten Gnad
- Institute of Pharmacology and Toxicology, University of Bonn, 53127, Bonn, Germany
| | - Johannes Kerner
- Department of Pharmacology, Experimental Therapy and Toxicology and Interfaculty Center of Pharmacoge-nomics and Drug Research, University of Tübingen, 72074, Tübingen, Germany
| | - Jyotsna Kaur
- Department of Pharmacology, Experimental Therapy and Toxicology and Interfaculty Center of Pharmacoge-nomics and Drug Research, University of Tübingen, 72074, Tübingen, Germany
| | - Tina Sartorius
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, University of Tuebingen, Tuebingen, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen (IDM), Tuebingen, Germany
| | - Jürgen Machann
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen (IDM), Tuebingen, Germany; Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University of Tuebingen, Germany
| | - Fritz Schick
- Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University of Tuebingen, Germany
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC, USA; Institute of Biomedical Research (BIOMED), Catholic University of Argentina, Buenos Aires, Argentina
| | - Hans-Ulrich Häring
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, University of Tuebingen, Tuebingen, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen (IDM), Tuebingen, Germany
| | - Alexander Pfeifer
- Institute of Pharmacology and Toxicology, University of Bonn, 53127, Bonn, Germany
| | - Bernd Nürnberg
- Department of Pharmacology, Experimental Therapy and Toxicology and Interfaculty Center of Pharmacoge-nomics and Drug Research, University of Tübingen, 72074, Tübingen, Germany.
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Toyonaga T, Steinbach EC, Keith BP, Barrow JB, Schaner MR, Wolber EA, Beasley C, Huling J, Wang Y, Allbritton NL, Chaumont N, Sadiq TS, Koruda MJ, Jain A, Long MD, Barnes EL, Herfarth HH, Isaacs KL, Hansen JJ, Shanahan MT, Rahbar R, Furey TS, Sethupathy P, Sheikh SZ. Decreased Colonic Activin Receptor-Like Kinase 1 Disrupts Epithelial Barrier Integrity in Patients With Crohn's Disease. Cell Mol Gastroenterol Hepatol 2020; 10:779-796. [PMID: 32561494 PMCID: PMC7502566 DOI: 10.1016/j.jcmgh.2020.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/09/2020] [Accepted: 06/09/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Intestinal epithelial cell (IEC) barrier dysfunction is critical to the development of Crohn's disease (CD). However, the mechanism is understudied. We recently reported increased microRNA-31-5p (miR-31-5p) expression in colonic IECs of CD patients, but downstream targets and functional consequences are unknown. METHODS microRNA-31-5p target genes were identified by integrative analysis of RNA- and small RNA-sequencing data from colonic mucosa and confirmed by quantitative polymerase chain reaction in colonic IECs. Functional characterization of activin receptor-like kinase 1 (ACVRL1 or ALK1) in IECs was performed ex vivo using 2-dimensional cultured human primary colonic IECs. The impact of altered colonic ALK1 signaling in CD for the risk of surgery and endoscopic relapse was evaluated by a multivariate regression analysis and a Kaplan-Meier estimator. RESULTS ALK1 was identified as a target of miR-31-5p in colonic IECs of CD patients and confirmed using a 3'-untranslated region reporter assay. Activation of ALK1 restricted the proliferation of colonic IECs in a 5-ethynyl-2-deoxyuridine proliferation assay and down-regulated the expression of stemness-related genes. Activated ALK1 signaling increased colonic IEC differentiation toward colonocytes. Down-regulated ALK1 signaling was associated with increased stemness and decreased colonocyte-specific marker expression in colonic IECs of CD patients compared with healthy controls. Activation of ALK1 enhanced epithelial barrier integrity in a transepithelial electrical resistance permeability assay. Lower colonic ALK1 expression was identified as an independent risk factor for surgery and was associated with a higher risk of endoscopic relapse in CD patients. CONCLUSIONS Decreased colonic ALK1 disrupted colonic IEC barrier integrity and was associated with poor clinical outcomes in CD patients.
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Affiliation(s)
- Takahiko Toyonaga
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Erin C. Steinbach
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina,Division of Rheumatology, Allergy and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Benjamin P. Keith
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina,Department of Genetics, Department of Biology, Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Jasmine B. Barrow
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Matthew R. Schaner
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Elisabeth A. Wolber
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Caroline Beasley
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Jennifer Huling
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Yuli Wang
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Nancy L. Allbritton
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Nicole Chaumont
- Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Timothy S. Sadiq
- Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Mark J. Koruda
- Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Animesh Jain
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Millie D. Long
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Edward L. Barnes
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Hans H. Herfarth
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Kim L. Isaacs
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Jonathan J. Hansen
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Michael T. Shanahan
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Reza Rahbar
- Department of Surgery, Rex Healthcare of Wakefield, North Carolina
| | - Terrence S. Furey
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina,Department of Genetics, Department of Biology, Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Praveen Sethupathy
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Shehzad Z. Sheikh
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina,Correspondence Address correspondence to: Shehzad Z. Sheikh, MD, Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, 7314 Medical Biomolecular Research Building, 111 Mason Farm Road, Chapel Hill, North Carolina 27599. fax: (919) 843-2585.
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8
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van den Bos E, Ambrosy B, Horsthemke M, Walbaum S, Bachg AC, Wettschureck N, Innamorati G, Wilkie TM, Hanley PJ. Knockout mouse models reveal the contributions of G protein subunits to complement C5a receptor-mediated chemotaxis. J Biol Chem 2020; 295:7726-7742. [PMID: 32332099 DOI: 10.1074/jbc.ra119.011984] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/22/2020] [Indexed: 01/20/2023] Open
Abstract
G protein-coupled receptor signaling is required for the navigation of immune cells along chemoattractant gradients. However, chemoattractant receptors may couple to more than one type of heterotrimeric G protein, each of which consists of a Gα, Gβ, and Gγ subunit, making it difficult to delineate the critical signaling pathways. Here, we used knockout mouse models and time-lapse microscopy to elucidate Gα and Gβ subunits contributing to complement C5a receptor-mediated chemotaxis. Complement C5a-mediated chemokinesis and chemotaxis were almost completely abolished in macrophages lacking Gnai2 (encoding Gαi2), consistent with a reduced leukocyte recruitment previously observed in Gnai2 -/- mice, whereas cells lacking Gnai3 (Gαi3) exhibited only a slight decrease in cell velocity. Surprisingly, C5a-induced Ca2+ transients and lamellipodial membrane spreading were persistent in Gnai2 -/- macrophages. Macrophages lacking both Gnaq (Gαq) and Gna11 (Gα11) or both Gna12 (Gα12) and Gna13 (Gα13) had essentially normal chemotaxis, Ca2+ signaling, and cell spreading, except Gna12/Gna13-deficient macrophages had increased cell velocity and elongated trailing ends. Moreover, Gnaq/Gna11-deficient cells did not respond to purinergic receptor P2Y2 stimulation. Genetic deletion of Gna15 (Gα15) virtually abolished C5a-induced Ca2+ transients, but chemotaxis and cell spreading were preserved. Homozygous Gnb1 (Gβ1) deletion was lethal, but mice lacking Gnb2 (Gβ2) were viable. Gnb2 -/- macrophages exhibited robust Ca2+ transients and cell spreading, albeit decreased cell velocity and impaired chemotaxis. In summary, complement C5a-mediated chemotaxis requires Gαi2 and Gβ2, but not Ca2+ signaling, and membrane protrusive activity is promoted by G proteins that deplete phosphatidylinositol 4,5-bisphosphate.
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Affiliation(s)
- Esther van den Bos
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Benjamin Ambrosy
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Markus Horsthemke
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Stefan Walbaum
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Anne C Bachg
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Nina Wettschureck
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Giulio Innamorati
- Department of Surgical Sciences, Dentistry, Gynecology and Pediatrics, University of Verona, Verona, Italy
| | - Thomas M Wilkie
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Peter J Hanley
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, Münster, Germany
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Li ZW, Sun B, Gong T, Guo S, Zhang J, Wang J, Sugawara A, Jiang M, Yan J, Gurary A, Zheng X, Gao B, Xiao SY, Chen W, Ma C, Farrar C, Zhu C, Chan OTM, Xin C, Winnicki A, Winnicki J, Tang M, Park R, Winnicki M, Diener K, Wang Z, Liu Q, Chu CH, Arter ZL, Yue P, Alpert L, Hui GS, Fei P, Turkson J, Yang W, Wu G, Tao A, Ramos JW, Moisyadi S, Holcombe RF, Jia W, Birnbaumer L, Zhou X, Chu WM. GNAI1 and GNAI3 Reduce Colitis-Associated Tumorigenesis in Mice by Blocking IL6 Signaling and Down-regulating Expression of GNAI2. Gastroenterology 2019; 156:2297-2312. [PMID: 30836096 PMCID: PMC6628260 DOI: 10.1053/j.gastro.2019.02.040] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 02/06/2019] [Accepted: 02/28/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Interleukin 6 (IL6) and tumor necrosis factor contribute to the development of colitis-associated cancer (CAC). We investigated these signaling pathways and the involvement of G protein subunit alpha i1 (GNAI1), GNAI2, and GNAI3 in the development of CAC in mice and humans. METHODS B6;129 wild-type (control) or mice with disruption of Gnai1, Gnai2, and/or Gnai3 or conditional disruption of Gnai2 in CD11c+ or epithelial cells were given dextran sulfate sodium (DSS) to induce colitis followed by azoxymethane (AOM) to induce carcinogenesis; some mice were given an antibody against IL6. Feces were collected from mice, and the compositions of microbiomes were analyzed by polymerase chain reactions. Dendritic cells (DCs) and myeloid-derived suppressor cells (MDSCs) isolated from spleen and colon tissues were analyzed by flow cytometry. We performed immunoprecipitation and immunoblot analyses of colon tumor tissues, MDSCs, and mouse embryonic fibroblasts to study the expression levels of GNAI1, GNAI2, and GNAI3 and the interactions of GNAI1 and GNAI3 with proteins in the IL6 signaling pathway. We analyzed the expression of Gnai2 messenger RNA by CD11c+ cells in the colonic lamina propria by PrimeFlow, expression of IL6 in DCs by flow cytometry, and secretion of cytokines in sera and colon tissues by enzyme-linked immunosorbent assay. We obtained colon tumor and matched nontumor tissues from 83 patients with colorectal cancer having surgery in China and 35 patients with CAC in the United States. Mouse and human colon tissues were analyzed by histology, immunoblot, immunohistochemistry, and/or RNA-sequencing analyses. RESULTS GNAI1 and GNAI3 (GNAI1;3) double-knockout (DKO) mice developed more severe colitis after administration of DSS and significantly more colonic tumors than control mice after administration of AOM plus DSS. Development of increased tumors in DKO mice was not associated with changes in fecal microbiomes but was associated with activation of nuclear factor (NF) κB and signal transducer and activator of transcription (STAT) 3; increased levels of GNAI2, nitric oxide synthase 2, and IL6; increased numbers of CD4+ DCs and MDSCs; and decreased numbers of CD8+ DCs. IL6 was mainly produced by CD4+/CD11b+, but not CD8+, DCs in DKO mice. Injection of DKO mice with a blocking antibody against IL6 reduced the expansion of MDSCs and the number of tumors that developed after CAC induction. Incubation of MDSCs or mouse embryonic fibroblasts with IL6 induced activation of either NF-κB by a JAK2-TRAF6-TAK1-CHUK/IKKB signaling pathway or STAT3 by JAK2. This activation resulted in expression of GNAI2, IL6 signal transducer (IL6ST, also called GP130) and nitric oxide synthase 2, and expansion of MDSCs; the expression levels of these proteins and expansion of MDSCs were further increased by the absence of GNAI1;3 in cells and mice. Conditional disruption of Gnai2 in CD11c+ cells of DKO mice prevented activation of NF-κB and STAT3 and changes in numbers of DCs and MDSCs. Colon tumor tissues from patients with CAC had reduced levels of GNAI1 and GNAI3 and increased levels of GNAI2 compared with normal tissues. Further analysis of a public human colorectal tumor DNA microarray database (GSE39582) showed that low Gani1 and Gnai3 messenger RNA expression and high Gnai2 messenger RNA expression were significantly associated with decreased relapse-free survival. CONCLUSIONS GNAI1;3 suppresses DSS-plus-AOM-induced colon tumor development in mice, whereas expression of GNAI2 in CD11c+ cells and IL6 in CD4+/CD11b+ DCs appears to promote these effects. Strategies to induce GNAI1;3, or block GNAI2 and IL6, might be developed for the prevention or therapy of CAC in patients.
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Affiliation(s)
- Zhi-Wei Li
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Beicheng Sun
- Department of Hepatobiliary Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu, China
| | - Ting Gong
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Sheng Guo
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii; Department of Endocrine, Genetics and Metabolism, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Jianhua Zhang
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii; Department of Pediatrics, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Junlong Wang
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Atsushi Sugawara
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Meisheng Jiang
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
| | - Junjun Yan
- Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Alexandra Gurary
- Department of Tropical Medicine, Medical Microbiology, and Pharmacology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Xin Zheng
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Bifeng Gao
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Shu-Yuan Xiao
- Department of Pathology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China; Department of Pathology, University of Chicago, Chicago, Illinois
| | - Wenlian Chen
- Epidemiology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Chi Ma
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Christine Farrar
- The Microscopy, Imaging, and Flow Cytometry Shared Resource, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Chenjun Zhu
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Owen T M Chan
- Pathology Core, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Can Xin
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Andrew Winnicki
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - John Winnicki
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Mingxin Tang
- Center for Cardiovascular Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Ryan Park
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Mary Winnicki
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Katrina Diener
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Zhanwei Wang
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Qicai Liu
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii; Department of Cardiology and Heart Center, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Catherine H Chu
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Zhaohui L Arter
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Peibin Yue
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Lindsay Alpert
- Department of Pathology, University of Chicago, Chicago, Illinois
| | - George S Hui
- Department of Tropical Medicine, Medical Microbiology, and Pharmacology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Peiwen Fei
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - James Turkson
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Wentian Yang
- Department of Orthopedics, Rhode Island Hospital, Brown University Alpert Medical School, Providence, Rhode Island
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Augusta University, Augusta, Georgia
| | - Ailin Tao
- The Second Affiliated Hospital, The State Key Laboratory of Respiratory Disease, Guangdong Provincial Key Laboratory of Allergy and Clinical Immunology, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Joe W Ramos
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Stefan Moisyadi
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Randall F Holcombe
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Wei Jia
- Epidemiology Program, University of Hawaii Cancer Center, Honolulu, Hawaii
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina; Institute for Biomedical Research (BIOMED), Universidad Católica Argentina, Buenos Aires, Argentina
| | - Xiqiao Zhou
- Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China.
| | - Wen-Ming Chu
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii; The Second Affiliated Hospital, The State Key Laboratory of Respiratory Disease, Guangdong Provincial Key Laboratory of Allergy and Clinical Immunology, Guangzhou Medical University, Guangzhou, Guangdong, China.
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Csekő K, Beckers B, Keszthelyi D, Helyes Z. Role of TRPV1 and TRPA1 Ion Channels in Inflammatory Bowel Diseases: Potential Therapeutic Targets? Pharmaceuticals (Basel) 2019; 12:E48. [PMID: 30935063 PMCID: PMC6630403 DOI: 10.3390/ph12020048] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 12/20/2022] Open
Abstract
Inflammatory bowel diseases (IBD) have long been recognized to be accompanied by pain resulting in high morbidity. Transient receptor potential vanilloid 1 (TRPV1) and ankyrin 1 (TRPA1) ion channels located predominantly on the capsaicin-sensitive sensory neurons play a complex role in hyperalgesia and neurogenic inflammation. This review provides an overview of their expression and role in intestinal inflammation, in particular colitis, that appears to be virtually inconsistent based on the thorough investigations of the last twenty years. However, preclinical results with pharmacological interventions, as well as scarcely available human studies, more convincingly point out the potential therapeutic value of TRPV1 and TRPA1 antagonists in colitis and visceral hypersensitivity providing future therapeutical perspectives through a complex, unique mechanism of action for drug development in IBD.
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Affiliation(s)
- Kata Csekő
- Department of Pharmacology and Pharmacotherapy, Medical School and Molecular Pharmacology Research Group, Szentágothai Research Centre, University of Pécs, H-7624 Pécs, Hungary.
| | - Bram Beckers
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Center (MUMC+), 6202 AZ Maastricht, The Netherlands.
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University, 6202 AZ Maastricht, The Netherlands.
| | - Daniel Keszthelyi
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Center (MUMC+), 6202 AZ Maastricht, The Netherlands.
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University, 6202 AZ Maastricht, The Netherlands.
| | - Zsuzsanna Helyes
- Department of Pharmacology and Pharmacotherapy, Medical School and Molecular Pharmacology Research Group, Szentágothai Research Centre, University of Pécs, H-7624 Pécs, Hungary.
- PharmInVivo Ltd., H-7629 Pécs, Hungary.
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11
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Central role of G protein Gαi2 and Gαi2 + vomeronasal neurons in balancing territorial and infant-directed aggression of male mice. Proc Natl Acad Sci U S A 2019; 116:5135-5143. [PMID: 30804203 DOI: 10.1073/pnas.1821492116] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Aggression is controlled by the olfactory system in many animal species. In male mice, territorial and infant-directed aggression are tightly regulated by the vomeronasal organ (VNO), but how diverse subsets of sensory neurons convey pheromonal information to limbic centers is not yet known. Here, we employ genetic strategies to show that mouse vomeronasal sensory neurons expressing the G protein subunit Gαi2 regulate male-male and infant-directed aggression through distinct circuit mechanisms. Conditional ablation of Gαi2 enhances male-male aggression and increases neural activity in the medial amygdala (MeA), bed nucleus of the stria terminalis, and lateral septum. By contrast, conditional Gαi2 ablation causes reduced infant-directed aggression and decreased activity in MeA neurons during male-infant interactions. Strikingly, these mice also display enhanced parental behavior and elevated neural activity in the medial preoptic area, whereas sexual behavior remains normal. These results identify Gαi2 as the primary G protein α-subunit mediating the detection of volatile chemosignals in the apical layer of the VNO, and they show that Gαi2+ VSNs and the brain circuits activated by these neurons play a central role in orchestrating and balancing territorial and infant-directed aggression of male mice through bidirectional activation and inhibition of different targets in the limbic system.
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12
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Khan S, Godfrey V, Zaki MH. Cytosolic Nucleic Acid Sensors in Inflammatory and Autoimmune Disorders. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 344:215-253. [PMID: 30798989 DOI: 10.1016/bs.ircmb.2018.10.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Innate immunity employs germline-encoded pattern recognition receptors (PRRs) to sense microbial pattern molecules. Recognition of pathogen-associated molecular patterns (PAMPs) by various PPRs located on the cell membrane or in the cytosol leads to the activation of cell signaling pathways and production of inflammatory mediators. Nucleic acids including DNA, RNA, and their derivatives are potent PAMPs which can be recognized by multiple PRRs to induce inflammatory responses. While nucleic acid sensors can also sense endogenous nucleic acids, they are capable of discriminating self from non-self. However, defects in nucleic acid sensing PRRs or dysregulation of nucleic acid sensing signaling pathways may cause excessive activation of the immune system resulting in the development of inflammatory and autoimmune diseases. This review will discuss the major pathways for sensing intracellular nucleic acids and how defects in these nucleic acid sensing are associated with different kinds of autoimmune and inflammatory disorders.
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Affiliation(s)
- Shahanshah Khan
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Victoria Godfrey
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Md Hasan Zaki
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, United States.
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13
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Cani PD, Jordan BF. Gut microbiota-mediated inflammation in obesity: a link with gastrointestinal cancer. Nat Rev Gastroenterol Hepatol 2018; 15:671-682. [PMID: 29844585 DOI: 10.1038/s41575-018-0025-6] [Citation(s) in RCA: 224] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Overweight and obesity are associated with increased risk of developing metabolic disorders such as diabetes and cardiovascular diseases. However, besides these metabolic diseases, excess body weight is also associated with different cancers, including gastrointestinal cancers, such as liver, pancreatic and colon cancers. Inflammation is a common feature of both obesity and cancer; however, the origin of this inflammation has been largely debated. Over the past decade, growing evidence has shown that the composition of the gut microbiota and its activity might be associated not only with the onset of inflammation but also with metabolic disorders and cancer. Here, we review the links between the gut microbiota, gut barrier function and the onset of low-grade inflammation in the development of gastrointestinal cancer. We also describe the mechanisms by which specific microorganism-associated molecular patterns crosstalk with the immune system and how the metabolic activity of bacteria induces specific signalling pathways beyond the gut that eventually trigger carcinogenesis.
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Affiliation(s)
- Patrice D Cani
- Université catholique de Louvain, Louvain Drug Research Institute, WELBIO (Walloon Excellence in Life sciences and BIOtechnology), Metabolism and Nutrition Research Group, Brussels, Belgium.
| | - Benedicte F Jordan
- Université catholique de Louvain, Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Brussels, Belgium
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14
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Lian X, Beer-Hammer S, König GM, Kostenis E, Nürnberg B, Gollasch M. RXFP1 Receptor Activation by Relaxin-2 Induces Vascular Relaxation in Mice via a Gα i2-Protein/PI3Kß/γ/Nitric Oxide-Coupled Pathway. Front Physiol 2018; 9:1234. [PMID: 30233409 PMCID: PMC6131674 DOI: 10.3389/fphys.2018.01234] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Accepted: 08/15/2018] [Indexed: 01/10/2023] Open
Abstract
Background: Relaxins are small peptide hormones, which are novel candidate molecules that play important roles in cardiometablic syndrome. Relaxins are structurally related to the insulin hormone superfamily, which provide vasodilatory effects by activation of G-protein-coupled relaxin receptors (RXFPs) and stimulation of endogenous nitric oxide (NO) generation. Recently, relaxin could be demonstrated to activate Gi proteins and phosphoinositide 3-kinase (PI3K) pathways in cultured endothelial cells in vitro. However, the contribution of the Gi-PI3K pathway and their individual components in relaxin-dependent relaxation of intact arteries remains elusive. Methods: We used Gαi2- (Gnai2-/-) and Gαi3-deficient (Gnai3-/-) mice, pharmacological tools and wire myography to study G-protein-coupled signaling pathways involved in relaxation of mouse isolated mesenteric arteries by relaxins. Human relaxin-1, relaxin-2, and relaxin-3 were tested. Results: Relaxin-2 (∼50% relaxation at 10-11 M) was the most potent vasodilatory relaxin in mouse mesenteric arteries, compared to relaxin-1 and relaxin-3. The vasodilatory effects of relaxin-2 were inhibited by removal of the endothelium or treatment of the vessels with N (G)-nitro-L-arginine methyl ester (L-NAME, endothelial nitric oxide synthase (eNOS) inhibitor) or simazine (RXFP1 inhibitor). The vasodilatory effects of relaxin-2 were absent in arteries of mice treated with pertussis toxin (PTX). They were also absent in arteries isolated from Gnai2-/- mice, but not from Gnai3-/- mice. The effects were not affected by FR900359 (Gαq protein inhibitor) or PI-103 (PI3Kα inhibitor), but inhibited by TGX-221 (PI3Kβ inhibitor) or AS-252424 (PI3Kγ inhibitor). Simazine did not influence the anti-contractile effect of perivascular adipose tissue. Conclusion: Our data indicate that relaxin-2 produces endothelium- and NO-dependent relaxation of mouse mesenteric arteries by activation of RXFP1 coupled to Gi2-PI3K-eNOS pathway. Targeting vasodilatory Gi-protein-coupled RXFP1 pathways may provide promising opportunities for drug discovery in endothelial dysfunction and cardiometabolic disease.
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Affiliation(s)
- Xiaoming Lian
- Experimental and Clinical Research Center (ECRC), Charité - University Medicine Berlin and Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Sandra Beer-Hammer
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research (ICePhA), Tübingen, Germany
| | - Gabriele M König
- Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Evi Kostenis
- Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Bernd Nürnberg
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research (ICePhA), Tübingen, Germany
| | - Maik Gollasch
- Experimental and Clinical Research Center (ECRC), Charité - University Medicine Berlin and Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Medical Clinic for Nephrology and Internal Intensive Care, Charité Campus Virchow Klinikum, Berlin, Germany
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15
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Cao H, Qadri SM, Lang E, Pelzl L, Umbach AT, Leiss V, Birnbaumer L, Nürnberg B, Pieske B, Voelkl J, Gawaz M, Bissinger R, Lang F. Heterotrimeric G-protein subunit Gα i2 contributes to agonist-sensitive apoptosis and degranulation in murine platelets. Physiol Rep 2018; 6:e13841. [PMID: 30187671 PMCID: PMC6125243 DOI: 10.14814/phy2.13841] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 07/27/2018] [Indexed: 01/06/2023] Open
Abstract
Gαi2 , a heterotrimeric G-protein subunit, regulates various cell functions including ion channel activity, cell differentiation, proliferation and apoptosis. Platelet-expressed Gαi2 is decisive for the extent of tissue injury following ischemia/reperfusion. However, it is not known whether Gαi2 plays a role in the regulation of platelet apoptosis, which is characterized by caspase activation, cell shrinkage and cell membrane scrambling with phosphatidylserine (PS) translocation to the platelet surface. Stimulators of platelet apoptosis include thrombin and collagen-related peptide (CoRP), which are further known to enhance degranulation and activation of αIIb β3-integrin and caspases. Using FACS analysis, we examined the impact of agonist treatment on activation and apoptosis in platelets drawn from mice lacking Gαi2 and their wild-type (WT) littermates. As a result, treatment with either thrombin (0.01 U/mL) or CoRP (2 μg/mL or 5 μg/mL) significantly upregulated PS-exposure and significantly decreased forward scatter, reflecting cell size, in both genotypes. Exposure to CoRP triggered a significant increase in active caspase 3, ceramide formation, surface P-selectin, and αIIb β3-integrin activation. These molecular alterations were significantly less pronounced in Gαi2 -deficient platelets as compared to WT platelets. In conclusion, our data highlight a previously unreported role of Gαi2 signaling in governing platelet activation and apoptosis.
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Affiliation(s)
- Hang Cao
- Department of Vegetative & Clinical PhysiologyEberhard‐Karls UniversityTübingenGermany
| | - Syed M. Qadri
- Department of Pathology and Molecular MedicineMcMaster UniversityHamiltonOntarioCanada
- Centre for InnovationCanadian Blood ServicesHamiltonOntarioCanada
| | - Elisabeth Lang
- Department of Molecular Medicine IIHeinrich Heine UniversityDüsseldorfGermany
| | - Lisann Pelzl
- Department of Vegetative & Clinical PhysiologyEberhard‐Karls UniversityTübingenGermany
| | - Anja T. Umbach
- Department of Vegetative & Clinical PhysiologyEberhard‐Karls UniversityTübingenGermany
| | - Veronika Leiss
- Department of Pharmacology and Experimental TherapyInterfaculty Center of Pharmacology and Drug Research (ICePhA)Eberhard‐Karls UniversityTübingenGermany
| | - Lutz Birnbaumer
- Neurobiology LaboratoryNational Institute of Environmental Health SciencesNational Institutes of HealthDurhamNorth Carolina
- Institute of Biomedical Research (BIOMED)Catholic University of ArgentinaBuenos AiresArgentina
| | - Bernd Nürnberg
- Department of Pharmacology and Experimental TherapyInterfaculty Center of Pharmacology and Drug Research (ICePhA)Eberhard‐Karls UniversityTübingenGermany
| | - Burkert Pieske
- Department of Internal Medicine and CardiologyCharité‐Universitätsmedizin Berlin, and German Heart InstituteBerlinGermany
- Berlin Institute of Health (BIH)BerlinGermany
- DZHK (German Centre for Cardiovascular Research), partner siteBerlinGermany
| | - Jakob Voelkl
- Department of Internal Medicine and CardiologyCharité‐Universitätsmedizin Berlin, and German Heart InstituteBerlinGermany
- Berlin Institute of Health (BIH)BerlinGermany
- DZHK (German Centre for Cardiovascular Research), partner siteBerlinGermany
| | - Meinrad Gawaz
- Department of Internal Medicine IIIEberhard‐Karls UniversityTübingenGermany
| | - Rosi Bissinger
- Department of Internal Medicine IIIEberhard‐Karls UniversityTübingenGermany
| | - Florian Lang
- Department of Vegetative & Clinical PhysiologyEberhard‐Karls UniversityTübingenGermany
- Department of Molecular Medicine IIHeinrich Heine UniversityDüsseldorfGermany
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16
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Brink T, Leiss V, Siegert P, Jehle D, Ebner JK, Schwan C, Shymanets A, Wiese S, Nürnberg B, Hensel M, Aktories K, Orth JHC. Salmonella Typhimurium effector SseI inhibits chemotaxis and increases host cell survival by deamidation of heterotrimeric Gi proteins. PLoS Pathog 2018; 14:e1007248. [PMID: 30102745 PMCID: PMC6107295 DOI: 10.1371/journal.ppat.1007248] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 08/23/2018] [Accepted: 07/27/2018] [Indexed: 12/20/2022] Open
Abstract
Salmonella enterica serotype Typhimurium (S. Typhimurium) is one of the most frequent causes of food-borne illness in humans and usually associated with acute self-limiting gastroenteritis. However, in immunocompromised patients, the pathogen can disseminate and lead to severe systemic diseases. S. Typhimurium are facultative intracellular bacteria. For uptake and intracellular life, Salmonella translocate numerous effector proteins into host cells using two type-III secretion systems (T3SS), which are encoded within Salmonella pathogenicity islands 1 (SPI-1) and 2 (SPI-2). While SPI-1 effectors mainly promote initial invasion, SPI-2 effectors control intracellular survival and proliferation. Here, we elucidate the mode of action of Salmonella SPI-2 effector SseI, which is involved in control of systemic dissemination of S. Typhimurium. SseI deamidates a specific glutamine residue of heterotrimeric G proteins of the Gαi family, resulting in persistent activation of the G protein. Gi activation inhibits cAMP production and stimulates PI3-kinase γ by Gαi-released Gβγ subunits, resulting in activation of survival pathways by phosphorylation of Akt and mTOR. Moreover, SseI-induced deamidation leads to non-polarized activation of Gαi and, thereby, to loss of directed migration of dendritic cells. Salmonella Typhimurium is one of the most common causes of gastroenteritis in humans. In immunocompromised patients, the pathogen can cause systemic infections. Crucial virulence factors are encoded on two Salmonella pathogenicity islands SPI-1 and SPI-2. While SPI-1 encodes virulence factors essential for host cell invasion, intracellular proliferation of the pathogen depends mainly on SPI-2 effectors. Here, we elucidate the mode of action of Salmonella SPI-2 effector SseI. SseI activates heterotrimeric G proteins of the Gαi family by deamidation of a specific glutamine residue. Deamidation blocks GTP hydrolysis by Gαi, resulting in a persistently active G protein. Gi activation inhibits cAMP production and stimulates PI3Kγ by Gαi-released Gβγ subunits, resulting in activation of survival pathways by phosphorylation of Akt and mTOR. Moreover, deamidation of Gαi leads to a loss of directed migration in dendritic cells. The data offers a new perspective in the understanding of the actions of SseI.
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Affiliation(s)
- Thorsten Brink
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Veronika Leiss
- Abteilung für Pharmakologie und Experimentelle Therapie, Medizinische Fakultät und ICePhA, Eberhard-Karls-Universität Tübingen, Germany
| | - Peter Siegert
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Doris Jehle
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Julia K. Ebner
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- Fakultät für Biologie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Carsten Schwan
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Aliaksei Shymanets
- Abteilung für Pharmakologie und Experimentelle Therapie, Medizinische Fakultät und ICePhA, Eberhard-Karls-Universität Tübingen, Germany
| | - Sebastian Wiese
- Zentrum für Biosystemanalyse, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Bernd Nürnberg
- Abteilung für Pharmakologie und Experimentelle Therapie, Medizinische Fakultät und ICePhA, Eberhard-Karls-Universität Tübingen, Germany
| | - Michael Hensel
- Abteilung Mikrobiologie, Fachbereich Biologie/Chemie, Universität Osnabrück, Osnabrück, Germany
| | - Klaus Aktories
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- * E-mail:
| | - Joachim H. C. Orth
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Medizinische Fakultät, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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Gα i3 signaling is associated with sexual dimorphic expression of the clock-controlled output gene Dbp in murine liver. Oncotarget 2018; 9:30213-30224. [PMID: 30100984 PMCID: PMC6084400 DOI: 10.18632/oncotarget.25727] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 06/14/2018] [Indexed: 11/25/2022] Open
Abstract
The albumin D-box binding protein (DBP) is a member of the PAR bZip (proline and acidic amino acid-rich basic leucine zipper) transcription factor family and functions as important regulator of circadian core and output gene expression. Gene expression of DBP itself is under the control of E-box-dependent binding by the Bmal1-Clock heterodimer and CRE-dependent binding by the cAMP responsive element binding protein (CREB). However, the signaling mechanism mediating CREB-dependent regulation of DBP expression in the peripheral clock remains elusive. In this study, we examined the role of the GPCR (G-protein-coupled receptor)/Gαi3 (Galphai3) controlled cAMP-CREB signaling pathway in the regulation of hepatic expression of core clock and clock-regulated genes, including Dbp. Analysis of circadian gene expression revealed that rhythmicity of hepatic transcript levels of the majority of core clock (including Per1) and clock-regulated genes were not affected by Gαi3 deficiency. Consistently, the period length of primary Gαi3 deficient tail fibroblasts expressing a Bmal1-Luciferase reporter was not affected. Interestingly, however, Gαi3 deficient female but not male mice showed a tendentiously increased activation of CREB (nuclear pSer133-CREB) accompanied by an advanced peak in Dbp gene expression and elevated mRNA levels of the cytochrome P450 family member Cyp3a11, a target gene of DBP. Accordingly, selective inhibition of CREB led to a strongly decreased expression of DBP and CYP3A4 (human Cyp3a11 homologue) in HepG2 liver cells. In summary, our data suggest that the Gαi3-pCREB signalling pathway functions as a regulator of sexual-dimorphic expression of DBP and its xenobiotic target enzymes Cyp3a11/CYP3A4.
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18
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Genetics and mechanisms leading to human cortical malformations. Semin Cell Dev Biol 2018; 76:33-75. [DOI: 10.1016/j.semcdb.2017.09.031] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 09/21/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023]
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MicroRNA-222-3p/GNAI2/AKT axis inhibits epithelial ovarian cancer cell growth and associates with good overall survival. Oncotarget 2018; 7:80633-80654. [PMID: 27811362 PMCID: PMC5348346 DOI: 10.18632/oncotarget.13017] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 10/22/2016] [Indexed: 12/17/2022] Open
Abstract
Ovarian carcinoma is the most lethal gynecologic tumor worldwide. Despite having developed molecular diagnostic tools and targeted therapies over the past few decades, patient survival is still quite poor. Numerous studies suggest that microRNAs are key regulators of many fundamental biological processes, including neoplasia and tumor progression. miR-222 is one of those miRNAs that has attracted much attention for its multiple roles in human diseases, especially cancer. The potential role of microRNAs in ovarian cancer has attracted much attention in recent years. Some of these microRNAs have been suggested as potential therapeutic targets for EOC patients. In this study, we sought to investigate the biologic functions of miR-222-3p in EOC carcinogenesis. Herein, we examined the expression of miR-222-3p in EOC patients, mouse models and cell lines, and found that higher expression of miR-222-3p was associated with better overall survival in EOC patients, and its level was negatively correlated with tumor growth in vivo. Furthermore, in-vitro experiments indicated that miR-222-3p inhibited EOC cell proliferation and migration, and decreased the phosphorylation of AKT. We identified GNAI2 as a target of miR-222-3p. We also found that GNAI2 promoted EOC cell proliferation, and is an activator of the PI3K/AKT pathway. We describe the characterization of a novel regulatory axis in ovarian cancer cells, miR-222-3p/GNAI2/AKT and its potential application as a therapeutic target for EOC patients.
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20
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Loss of Gα i proteins impairs thymocyte development, disrupts T-cell trafficking, and leads to an expanded population of splenic CD4 +PD-1 +CXCR5 +/- T-cells. Sci Rep 2017. [PMID: 28646160 PMCID: PMC5482867 DOI: 10.1038/s41598-017-04537-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Thymocyte and T cell trafficking relies on signals initiated by G-protein coupled receptors. To address the importance of the G-proteins Gαi2 and Gαi3 in thymocyte and T cell function, we developed several mouse models. Gαi2 deficiency in hematopoietic progenitors led to a small thymus, a double negative (DN)1/DN2 thymocyte transition block, and an accumulation of mature single positive (SP) thymocytes. Loss at the double positive (DP) stage of thymocyte development caused an increase in mature cells within the thymus. In both models an abnormal distribution of memory and naïve CD4 T cells occurred, and peripheral CD4 and CD8 T cells had reduced chemoattractant responses. The loss of Gαi3 had no discernable impact, however the lack of both G-proteins commencing at the DP stage caused a severe T cell phenotype. These mice lacked a thymic medullary region, exhibited thymocyte retention, had a peripheral T cell deficiency, and lacked T cell chemoattractant responses. Yet a noteworthy population of CD4+PD-1+CXCR5+/− cells resided in the spleen of these mice likely due to a loss of regulatory T cell function. Our results delineate a role for Gαi2 in early thymocyte development and for Gαi2/3 in multiple aspects of T cell biology.
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21
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Elevated fecal peptidase D at onset of colitis in Galphai2-/- mice, a mouse model of IBD. PLoS One 2017; 12:e0174275. [PMID: 28323866 PMCID: PMC5360340 DOI: 10.1371/journal.pone.0174275] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/06/2017] [Indexed: 01/15/2023] Open
Abstract
Background The identification of novel fecal biomarkers in inflammatory bowel disease (IBD) is hampered by the complexity of the human fecal proteome. On the other hand, in experimental mouse models there is probably less variation. We investigated the fecal protein content in mice to identify possible biomarkers and pathogenic mechanisms. Methods Fecal samples were collected at onset of inflammation in Galphai2-/- mice, a well-described spontaneous model of chronic colitis, and from healthy littermates. The fecal proteome was analyzed by two-dimensional electrophoresis and quantitative mass spectrometry and results were then validated in a new cohort of mice. Results As a potential top marker of disease, peptidase D was found at a higher ratio in Galphai2-/- mouse feces relative to controls (fold change 27; p = 0.019). Other proteins found to be enriched in Gαi2-/- mice were mainly pancreatic proteases, and proteins from plasma and blood cells. A tendency of increased calprotectin, subunit S100-A8, was also observed (fold change 21; p = 0.058). Proteases are potential activators of inflammation in the gastrointestinal tract through their interaction with the proteinase-activated receptor 2 (PAR2). Accordingly, the level of PAR2 was found to be elevated in both the colon and the pancreas of Galphai2-/- mice at different stages of disease. Conclusions These findings identify peptidase D, an ubiquitously expressed intracellular peptidase, as a potential novel marker of colitis. The elevated levels of fecal proteases may be involved in the pathogenesis of colitis and contribute to the clinical phenotype, possibly by activation of intestinal PAR2.
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22
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Robichaux WG, Branham-O'Connor M, Hwang IY, Vural A, Kehrl JH, Blumer JB. Regulation of Chemokine Signal Integration by Activator of G-Protein Signaling 4 (AGS4). J Pharmacol Exp Ther 2017; 360:424-433. [PMID: 28062526 DOI: 10.1124/jpet.116.238436] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 12/28/2016] [Indexed: 12/15/2022] Open
Abstract
Activator of G-protein signaling 4 (AGS4)/G-protein signaling modulator 3 (Gpsm3) contains three G-protein regulatory (GPR) motifs, each of which can bind Gαi-GDP free of Gβγ We previously demonstrated that the AGS4-Gαi interaction is regulated by seven transmembrane-spanning receptors (7-TMR), which may reflect direct coupling of the GPR-Gαi module to the receptor analogous to canonical Gαβγ heterotrimer. We have demonstrated that the AGS4-Gαi complex is regulated by chemokine receptors in an agonist-dependent manner that is receptor-proximal. As an initial approach to investigate the functional role(s) of this regulated interaction in vivo, we analyzed leukocytes, in which AGS4/Gpsm3 is predominantly expressed, from AGS4/Gpsm3-null mice. Loss of AGS4/Gpsm3 resulted in mild but significant neutropenia and leukocytosis. Dendritic cells, T lymphocytes, and neutrophils from AGS4/Gpsm3-null mice also exhibited significant defects in chemoattractant-directed chemotaxis and extracellular signal-regulated kinase activation. An in vivo peritonitis model revealed a dramatic reduction in the ability of AGS4/Gpsm3-null neutrophils to migrate to primary sites of inflammation. Taken together, these data suggest that AGS4/Gpsm3 is required for proper chemokine signal processing in leukocytes and provide further evidence for the importance of the GPR-Gαi module in the regulation of leukocyte function.
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Affiliation(s)
- William G Robichaux
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina (W.G.R., M.B.-O., J.B.B.); and B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland (I.-Y.H., A.V., J.H.K.)
| | - Melissa Branham-O'Connor
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina (W.G.R., M.B.-O., J.B.B.); and B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland (I.-Y.H., A.V., J.H.K.)
| | - Il-Young Hwang
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina (W.G.R., M.B.-O., J.B.B.); and B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland (I.-Y.H., A.V., J.H.K.)
| | - Ali Vural
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina (W.G.R., M.B.-O., J.B.B.); and B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland (I.-Y.H., A.V., J.H.K.)
| | - Johne H Kehrl
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina (W.G.R., M.B.-O., J.B.B.); and B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland (I.-Y.H., A.V., J.H.K.)
| | - Joe B Blumer
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina (W.G.R., M.B.-O., J.B.B.); and B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland (I.-Y.H., A.V., J.H.K.)
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23
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Zhu H, Xu WY, Hu Z, Zhang H, Shen Y, Lu S, Wei C, Wang ZG. RNA virus receptor Rig-I monitors gut microbiota and inhibits colitis-associated colorectal cancer. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2017; 36:2. [PMID: 28057020 PMCID: PMC5217425 DOI: 10.1186/s13046-016-0471-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 12/06/2016] [Indexed: 12/15/2022]
Abstract
Background Retinoic acid-inducible gene-I (Rig-I) is an intracellular viral RNA receptor, which specifically recognizes double-stranded viral RNA initiating antiviral innate immunity. Increasing evidences showed that Rig-I had broader roles in antibacterial immunity and cancer protection. However, the potential roles and mechanisms of Rig-I in gut flora regulation and colorectal cancer (CRC) progression remain unclear. Methods Immunohistochemistry was performed to detect Rig-I protein in 38 pairs of CRC tissue and matched adjacent mucosa, and immunofluorescence and western blot were also used to detect Rig-I protein expression in AOM/DSS-induced mice CRC samples. High-throughput sequencing was conducted to evaluate gut microbiota changes in Rig-I-deficient mice. Immunofluorescence and flow cytometry were used to detect IgA expression. Additionally, real-time quantitative PCR was performed to detect RNA expression in mouse intestines and cultured cells, and western blot was used to detect phosphorylation of STAT3 in IL-6-stimulated B cell line. Results Rig-I was downregulated in human and mouse CRC samples and Rig-I-deficient mice were more susceptible to AOM/DSS-induced colitis-associated colorectal cancer (CAC). Furthermore, Rig-I-deficient mice displayed gut microbiota disturbance compared to wild type mice. IgA, Reg3γ and Pdcd1 levels were decreased in intestines of Rig-I-deficient mice. Phosphorylation of STAT3 in IL-6-stimulated 1B4B6 was decreased. Conclusion Rig-I could regulate gut microbiota through regulating IgA and IL6-STAT3-dependent Reg3γ expression. Besides, Rig-I could inhibit CRC progression. Electronic supplementary material The online version of this article (doi:10.1186/s13046-016-0471-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Houbao Zhu
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. .,Model Organism Division, E-Institutes of Shanghai Universities, Shanghai, China. .,Research Center for Experimental Medicine, Rui-Jin Hospital, 197 Ruijin Road II, Shanghai, 200025, China.
| | - Wang-Yang Xu
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Model Organism Division, E-Institutes of Shanghai Universities, Shanghai, China
| | - Zhiqiang Hu
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Center for Bioinformation Technology, Shanghai, China
| | - Hongxin Zhang
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Model Organism Division, E-Institutes of Shanghai Universities, Shanghai, China
| | - Yan Shen
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shunyuan Lu
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Model Organism Division, E-Institutes of Shanghai Universities, Shanghai, China
| | - Chaochun Wei
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China. .,Shanghai Center for Bioinformation Technology, Shanghai, China. .,Research Center for Experimental Medicine, Rui-Jin Hospital, 197 Ruijin Road II, Shanghai, 200025, China.
| | - Zhu-Gang Wang
- State Key Laboratory of Medical Genomics, Research Center for Experimental Medicine of Rui-Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. .,Model Organism Division, E-Institutes of Shanghai Universities, Shanghai, China. .,Shanghai Research Center for Model Organisms, Shanghai, China. .,Research Center for Experimental Medicine, Rui-Jin Hospital, 197 Ruijin Road II, Shanghai, 200025, China.
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Abstract
Ulcerative colitis is a common chronic inflammatory disease of the colon and rectum, resulting from a dysregulated immune response towards intraluminal antigens in a genetically predisposed host. The disease has a varying extent and severity. Approximately 20% of patients with ulcerative colitis experience a severe flare during the course of their disease, requiring hospitalization. Acute severe ulcerative colitis (ASUC) is potentially a life-threatening condition that requires early recognition, hospitalization, correction of body fluids and electrolytes, and nutritional support if needed. Superimposed bacterial or viral infections need to be excluded and thromboprophylaxis should be started. Intravenous corticosteroids are the first-line treatment for this condition. Rescue treatment with ciclosporin or infliximab is indicated in patients who do not sufficiently respond to corticosteroids after 3-5 days, with close monitoring of the patients' symptoms, serum C-reactive protein and albumin levels. If medical therapy fails, timely colectomy should be performed to prevent critical complications. In this article, we review all relevant aspects of ASUC, from its pathophysiological background to modern management in clinical practice.
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25
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Ali El-Basyuni Y, Li Y, Anand-Srivastava MB. Knockdown of Inhibitory Guanine Nucleotide Binding Protein Giα-2 by Antisense Oligodeoxynucleotides Attenuates the Development of Hypertension and Tachycardia in Spontaneously Hypertensive Rats. J Am Heart Assoc 2016; 5:e004594. [PMID: 27912212 PMCID: PMC5210347 DOI: 10.1161/jaha.116.004594] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 09/30/2016] [Indexed: 11/16/2022]
Abstract
BACKGROUND We previously showed that the levels of both Giα-2 and Giα-3 proteins were augmented in spontaneously hypertensive rats (SHRs) before the onset of hypertension. In addition, intraperitoneal injection of pertussis toxin, which inactivates both Giα proteins, prevented the development of hypertension in SHRs. The aim of the present study was to determine the specific contributions of Giα-2 and Giα-3 proteins to the development of hypertension. METHODS AND RESULTS Antisense oligodeoxynucleotide of Giα-2 and Giα-3 encapsulated in PEG/DOTAP/DOPE cationic liposomes were administrated intravenously into 3-week-old prehypertensive SHRs and Wistar Kyoto rats, whereas the control Wistar Kyoto rats and SHRs received PBS, empty liposomes, or sense. The knockdown of Giα-2 but not Giα-3 protein attenuated tachycardia and prevented the development of hypertension up to age 6 weeks; thereafter, blood pressure started increasing and reached the same level as that of untreated SHRs at 9 weeks. Furthermore, Giα-2 and Giα-3 antisense oligodeoxynucleotide treatments significantly decreased the enhanced levels of Giα-2 and Giα-3 proteins, respectively, and enhanced levels of superoxide anion and NADPH oxidase activity in heart, aorta, and kidney and hyperproliferation of vascular smooth muscle cells from SHRs aged 6 weeks. In addition, antisense oligodeoxynucleotide treatment with Giα-2 but not Giα-3 restored enhanced inhibition of adenylyl cyclase by oxotremorine to WKY levels. CONCLUSIONS These results suggested that the enhanced expression of Giα-2 but not Giα-3 protein plays an important role in the pathogenesis of hypertension and tachycardia in SHRs.
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MESH Headings
- Adenylyl Cyclase Inhibitors/pharmacology
- Animals
- Aorta/metabolism
- Blood Pressure/physiology
- Cells, Cultured
- Disease Models, Animal
- GTP-Binding Protein alpha Subunit, Gi2/deficiency
- GTP-Binding Protein alpha Subunit, Gi2/physiology
- GTP-Binding Protein alpha Subunits, Gi-Go/deficiency
- GTP-Binding Protein alpha Subunits, Gi-Go/physiology
- Gene Knockdown Techniques
- Heart Rate/physiology
- Hypertension/prevention & control
- Kidney/metabolism
- Liposomes/administration & dosage
- Male
- Muscle, Smooth, Vascular/metabolism
- Myocardium/metabolism
- Oligodeoxyribonucleotides, Antisense/physiology
- Rats, Inbred SHR
- Rats, Inbred WKY
- Signal Transduction/physiology
- Tachycardia/prevention & control
- Transfection/methods
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Affiliation(s)
- Yousra Ali El-Basyuni
- Department of Molecular and Integrative Physiology, Faculty of Medicine, University of Montreal, Quebec, Canada
| | - Yuan Li
- Department of Molecular and Integrative Physiology, Faculty of Medicine, University of Montreal, Quebec, Canada
| | - Madhu B Anand-Srivastava
- Department of Molecular and Integrative Physiology, Faculty of Medicine, University of Montreal, Quebec, Canada
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26
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Lino AC, Dörner T, Bar-Or A, Fillatreau S. Cytokine-producing B cells: a translational view on their roles in human and mouse autoimmune diseases. Immunol Rev 2016; 269:130-44. [PMID: 26683150 DOI: 10.1111/imr.12374] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
B-cell depletion therapy has beneficial effects in autoimmune diseases. This is only partly explained by an elimination of autoantibodies. How does B-cell depletion improve disease? Here, we review preclinical studies showing that B cells can propagate autoimmune disorders through cytokine production. We also highlight clinical observations indicating the relevance of these B-cell functions in human autoimmunity. Abnormalities in B-cell cytokine production have been observed in rheumatoid arthritis, multiple sclerosis, inflammatory bowel disease, and systemic lupus erythematosus. In the first two diseases, B-cell depletion erases these abnormalities, and improves disease progression, suggesting a causative role for defective B-cell cytokine expression in disease pathogenesis. However, in the last two disorders, the pathogenic role of B cells and the effect of B-cell depletion on cytokine-producing B cells remain to be clarified. A better characterization of cytokine-expressing human B-cell subsets, and their modulation by B cell-targeted therapies might help understanding both the successes and failures of current B cell-targeted approaches. This may even lead to the development of novel strategies to deplete or amplify selectively pathogenic or protective subsets, respectively, which might be more effective than global depletion of the B-cell compartment.
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Affiliation(s)
- Andreia C Lino
- Deutsches Rheuma-Forschungszentrum, A Leibniz Institute, Berlin, Germany
| | - Thomas Dörner
- Deutsches Rheuma-Forschungszentrum, A Leibniz Institute, Berlin, Germany.,CC12, Department of Medicine/Rheumatology and Clinical Immunology, Charité University Medicine Berlin, Berlin, Germany
| | - Amit Bar-Or
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, 3801 University, Montreal, QC, Canada
| | - Simon Fillatreau
- Deutsches Rheuma-Forschungszentrum, A Leibniz Institute, Berlin, Germany.,Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris, France.,Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Assistance Publique - Hôpitaux de Paris (AP-HP), Hôpital Necker Enfants Malades, Paris, France
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Abstract
B-1 lymphocytes exhibit unique phenotypic, ontogenic, and functional characteristics that differ from the conventional B-2 cells. B-1 cells spontaneously secrete germline-like, repertoire-skewed polyreactive natural antibody, which acts as a first line of defense by neutralizing a wide range of pathogens before launching of the adaptive immune response. Immunomodulatory molecules such as interleukin-10, adenosine, granulocyte-macrophage colony-stimulating factor, interleukin-3, and interleukin-35 are also produced by B-1 cells in the presence or absence of stimulation, which regulate acute and chronic inflammatory diseases. Considerable progress has been made during the past three decades since the discovery of B-1 cells, which has improved not only our understanding of their phenotypic and ontogenic uniqueness but also their role in various inflammatory diseases including influenza, pneumonia, sepsis, atherosclerosis, inflammatory bowel disease, autoimmunity, obesity and diabetes mellitus. Recent identification of human B-1 cells widens the scope of this field, leading to novel innovations that can be implemented from bench to bedside. Among the vast number of studies on B-1 cells, we have carried out a literature review highlighting current trends in the study of B-1 cell involvement during inflammation, which may result in a paradigm shift toward sustainable therapeutics in various inflammatory diseases.
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Affiliation(s)
- Monowar Aziz
- Center for Translational Research, Feinstein Institute for Medical Research, 350 Community Dr., Manhasset, NY, 11030, USA
| | - Nichol E Holodick
- Center for Oncology and Cell Biology, Feinstein Institute for Medical Research, 350 Community Dr., Manhasset, NY, 11030, USA
| | - Thomas L Rothstein
- Center for Oncology and Cell Biology, Feinstein Institute for Medical Research, 350 Community Dr., Manhasset, NY, 11030, USA
| | - Ping Wang
- Center for Translational Research, Feinstein Institute for Medical Research, 350 Community Dr., Manhasset, NY, 11030, USA. .,Department of Surgery, Hofstra North Shore-LIJ School of Medicine, 350 Community Dr., Manhasset, NY, 11030, USA.
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28
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Bissinger R, Lang E, Ghashghaeinia M, Singh Y, Zelenak C, Fehrenbacher B, Honisch S, Chen H, Fakhri H, Umbach AT, Liu G, Rexhepaj R, Liu G, Schaller M, Mack AF, Lupescu A, Birnbaumer L, Lang F, Qadri SM. Blunted apoptosis of erythrocytes in mice deficient in the heterotrimeric G-protein subunit Gαi2. Sci Rep 2016; 6:30925. [PMID: 27499046 PMCID: PMC4976336 DOI: 10.1038/srep30925] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 07/11/2016] [Indexed: 01/09/2023] Open
Abstract
Putative functions of the heterotrimeric G-protein subunit Gαi2-dependent signaling include ion channel regulation, cell differentiation, proliferation and apoptosis. Erythrocytes may, similar to apoptosis of nucleated cells, undergo eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine (PS) exposure. Eryptosis may be triggered by increased cytosolic Ca2+ activity and ceramide. In the present study, we show that Gαi2 is expressed in both murine and human erythrocytes and further examined the survival of erythrocytes drawn from Gαi2-deficient mice (Gαi2−/−) and corresponding wild-type mice (Gαi2+/+). Our data show that plasma erythropoietin levels, erythrocyte maturation markers, erythrocyte counts, hematocrit and hemoglobin concentration were similar in Gαi2−/− and Gαi2+/+ mice but the mean corpuscular volume was significantly larger in Gαi2−/− mice. Spontaneous PS exposure of circulating Gαi2−/− erythrocytes was significantly lower than that of circulating Gαi2+/+ erythrocytes. PS exposure was significantly lower in Gαi2−/− than in Gαi2+/+ erythrocytes following ex vivo exposure to hyperosmotic shock, bacterial sphingomyelinase or C6 ceramide. Erythrocyte Gαi2 deficiency further attenuated hyperosmotic shock-induced increase of cytosolic Ca2+ activity and cell shrinkage. Moreover, Gαi2−/− erythrocytes were more resistant to osmosensitive hemolysis as compared to Gαi2+/+ erythrocytes. In conclusion, Gαi2 deficiency in erythrocytes confers partial protection against suicidal cell death.
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Affiliation(s)
- Rosi Bissinger
- Institute of Cardiology, Vascular Medicine and Physiology, University of Tuebingen, Germany
| | - Elisabeth Lang
- Department of Gastroenterology, Hepatology and Infectious Diseases, University of Duesseldorf, Germany
| | - Mehrdad Ghashghaeinia
- Institute of Cardiology, Vascular Medicine and Physiology, University of Tuebingen, Germany
| | - Yogesh Singh
- Institute of Cardiology, Vascular Medicine and Physiology, University of Tuebingen, Germany
| | - Christine Zelenak
- Department of Internal Medicine, Charité Medical University, Berlin, Germany
| | | | - Sabina Honisch
- Institute of Cardiology, Vascular Medicine and Physiology, University of Tuebingen, Germany
| | - Hong Chen
- Institute of Cardiology, Vascular Medicine and Physiology, University of Tuebingen, Germany
| | - Hajar Fakhri
- Institute of Cardiology, Vascular Medicine and Physiology, University of Tuebingen, Germany
| | - Anja T Umbach
- Institute of Cardiology, Vascular Medicine and Physiology, University of Tuebingen, Germany
| | - Guilai Liu
- Institute of Cardiology, Vascular Medicine and Physiology, University of Tuebingen, Germany
| | - Rexhep Rexhepaj
- Institute of Cardiology, Vascular Medicine and Physiology, University of Tuebingen, Germany.,Institute of Biochemistry and Molecular Biology, University of Bonn, Germany
| | - Guoxing Liu
- Institute of Cardiology, Vascular Medicine and Physiology, University of Tuebingen, Germany
| | | | | | - Adrian Lupescu
- Institute of Cardiology, Vascular Medicine and Physiology, University of Tuebingen, Germany
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, USA
| | - Florian Lang
- Institute of Cardiology, Vascular Medicine and Physiology, University of Tuebingen, Germany
| | - Syed M Qadri
- Institute of Cardiology, Vascular Medicine and Physiology, University of Tuebingen, Germany.,Institute of Biomedical Research (BIOMED), School of Medical Sciences, Catholic University of Argentina, Buenos Aires, Argentina.,Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
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Bergstrom K, Liu X, Zhao Y, Gao N, Wu Q, Song K, Cui Y, Li Y, McDaniel JM, McGee S, Chen W, Huycke MM, Houchen CW, Zenewicz LA, West CM, Chen H, Braun J, Fu J, Xia L. Defective Intestinal Mucin-Type O-Glycosylation Causes Spontaneous Colitis-Associated Cancer in Mice. Gastroenterology 2016; 151:152-164.e11. [PMID: 27059389 PMCID: PMC5068133 DOI: 10.1053/j.gastro.2016.03.039] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 03/09/2016] [Accepted: 03/27/2016] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Core 1- and core 3-derived mucin-type O-linked oligosaccharides (O-glycans) are major components of the colonic mucus layer. Defective forms of colonic O-glycans, such as the Thomsen-nouveau (Tn) antigen, frequently are observed in patients with ulcerative colitis and colorectal cancer, but it is not clear if they contribute to their pathogenesis. We investigated whether and how impaired O-glycosylation contributes to the development of colitis-associated colorectal cancer using mice lacking intestinal core 1- and core 3-derived O-glycans. METHODS We generated mice that lack core 1- and core 3-derived intestinal O-glycans (DKO mice) and analyzed them, along with mice that singly lack intestinal epithelial core 1 O-glycans (IEC C1galt1(-/-) mice) or core 3 O-glycans (C3Gnt(-/-) mice). Intestinal tissues were collected at different time points and analyzed for levels of mucin and Tn antigen, development of colitis, and tumor formation using imaging, quantitative polymerase chain reaction, immunoblot, and enzyme-linked immunosorbent assay techniques. We also used cellular and genetic approaches, as well as intestinal microbiota depletion, to identify inflammatory mediators and pathways that contribute to disease in DKO and wild-type littermates (controls). RESULTS Intestinal tissues from DKO mice contained higher levels of Tn antigen and had more severe spontaneous chronic colitis than tissues from IEC C1galt1(-/-) mice, whereas spontaneous colitis was absent in C3GnT(-/-) and control mice. IEC C1galt1(-/-) mice and DKO mice developed spontaneous colorectal tumors, although the onset of tumors in the DKO mice occurred earlier (age, 8-9 months) than that in IEC C1galt1(-/-) mice (15 months old). Antibiotic depletion of the microbiota did not cause loss of Tn antigen but did reduce the development of colitis and cancer formation in DKO mice. Colon tissues from DKO mice, but not control mice, contained active forms of caspase 1 and increased caspase 11, which were reduced after antibiotic administration. Supernatants from colon tissues of DKO mice contained increased levels of interleukin-1β and interleukin-18, compared with those from control mice. Disruption of the caspase 1 and caspase 11 genes in DKO mice (DKO/Casp1/11(-/-) mice) decreased the development of colitis and cancer, characterized by reduced colonic thickening, hyperplasia, inflammatory infiltrate, and tumors compared with DKO mice. CONCLUSIONS Impaired expression of O-glycans causes colonic mucus barrier breach and subsequent microbiota-mediated activation of caspase 1-dependent inflammasomes in colonic epithelial cells of mice. These processes could contribute to colitis-associated colon cancer in humans.
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Affiliation(s)
- Kirk Bergstrom
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Xiaowei Liu
- Division of Digestive Disease, The 2nd Xiangya Hospital of Central South University, Changsha, Hunan 410011, China
| | - Yiming Zhao
- The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, China
| | - Nan Gao
- The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, China
| | - Qian Wu
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA,Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Fudan University, Shanghai 200032, China
| | - Kai Song
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Yi Cui
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Yun Li
- Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, China
| | - J. Michael McDaniel
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Samuel McGee
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Weichang Chen
- The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, China
| | - Mark M. Huycke
- The Muchmore Laboratories for Infectious Diseases Research, Department of Veterans Affairs Medical Center, Oklahoma City, Oklahoma, USA,Department of Internal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Courtney W. Houchen
- Department of Internal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Lauren A. Zenewicz
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Christopher M. West
- Department of Biochemistry and Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Hong Chen
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Jonathan Braun
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Jianxin Fu
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma; Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China.
| | - Lijun Xia
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma; Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China; Department of Biochemistry and Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.
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30
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RETRACTED ARTICLE: Mouse models of intestinal inflammation and cancer. Arch Toxicol 2016; 90:2109-2130. [DOI: 10.1007/s00204-016-1747-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 06/01/2016] [Indexed: 12/19/2022]
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31
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Benefits of short-chain fatty acids and their receptors in inflammation and carcinogenesis. Pharmacol Ther 2016; 164:144-51. [PMID: 27113407 DOI: 10.1016/j.pharmthera.2016.04.007] [Citation(s) in RCA: 332] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Indexed: 02/08/2023]
Abstract
Epidemiological studies have linked increased incidence of inflammatory diseases and intestinal cancers in the developed parts of the world to the consumption of diets poor in dietary fibers and rich in refined carbohydrates. Gut bacteria residing in the intestinal lumen exclusively metabolize dietary fibers. Butyrate, propionate and acetate, which are collectively called short-chain fatty acids (SCFAs), are generated by fermentation of dietary fibers by gut microbiota. Evidences indicate that SCFAs are key players in regulating beneficial effect of dietary fibers and gut microbiota on our health. SCFAs interact with metabolite-sensing G protein-coupled receptors GPR41, GPR43 and GPR109A expressed in gut epithelium and immune cells. These interactions induce mechanisms that play a key role in maintaining homeostasis in gut and other organs. This review summarizes the protective roles of GPR41, GPR43 and GPR109A in dietary fibers-, gut microbiota- and SCFAs-mediated suppression of inflammation and carcinogenesis in gut and other organs.
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Kehrl JH. The impact of RGS and other G-protein regulatory proteins on Gαi-mediated signaling in immunity. Biochem Pharmacol 2016; 114:40-52. [PMID: 27071343 DOI: 10.1016/j.bcp.2016.04.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 04/08/2016] [Indexed: 01/30/2023]
Abstract
Leukocyte chemoattractant receptors are members of the G-protein coupled receptor (GPCR) family. Signaling downstream of these receptors directs the localization, positioning and homeostatic trafficking of leukocytes; as well as their recruitment to, and their retention at, inflammatory sites. Ligand induced changes in the molecular conformation of chemoattractant receptors results in the engagement of heterotrimeric G-proteins, which promotes α subunits to undergo GTP/GDP exchange. This results in the functional release of βγ subunits from the heterotrimers, thereby activating downstream effector molecules, which initiate leukocyte polarization, gradient sensing, and directional migration. Pertussis toxin ADP ribosylates Gαi subunits and prevents chemoattractant receptors from triggering Gαi nucleotide exchange. The use of pertussis toxin revealed the essential importance of Gαi subunit nucleotide exchange for chemoattractant receptor signaling. More recent studies have identified a range of regulatory mechanisms that target these receptors and their associated heterotrimeric G-proteins, thereby helping to control the magnitude, kinetics, and duration of signaling. A failure in these regulatory pathways can lead to impaired receptor signaling and immunopathology. The analysis of mice with targeted deletions of Gαi isoforms as well as some of these G-protein regulatory proteins is providing insights into their roles in chemoattractant receptor signaling.
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Affiliation(s)
- John H Kehrl
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 2089, United States.
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33
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Using AAV vectors expressing the β2-adrenoceptor or associated Gα proteins to modulate skeletal muscle mass and muscle fibre size. Sci Rep 2016; 6:23042. [PMID: 26972746 PMCID: PMC4789796 DOI: 10.1038/srep23042] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 02/25/2016] [Indexed: 01/06/2023] Open
Abstract
Anabolic β2-adrenoceptor (β2-AR) agonists have been proposed as therapeutics for treating muscle wasting but concerns regarding possible off-target effects have hampered their use. We investigated whether β2-AR-mediated signalling could be modulated in skeletal muscle via gene delivery to the target tissue, thereby avoiding the risks of β2-AR agonists. In mice, intramuscular administration of a recombinant adeno-associated virus-based vector (rAAV vector) expressing the β2-AR increased muscle mass by >20% within 4 weeks. This hypertrophic response was comparable to that of 4 weeks’ treatment with the β2-AR agonist formoterol, and was not ablated by mTOR inhibition. Increasing expression of inhibitory (Gαi2) and stimulatory (GαsL) G-protein subunits produced minor atrophic and hypertrophic changes in muscle mass, respectively. Furthermore, Gαi2 over-expression prevented AAV:β2-AR mediated hypertrophy. Introduction of the non-muscle Gαs isoform, GαsXL elicited hypertrophy comparable to that achieved by AAV:β2-AR. Moreover, GαsXL gene delivery was found to be capable of inducing hypertrophy in the muscles of mice lacking functional β1- and β2-ARs. These findings demonstrate that gene therapy-based interventions targeting the β2-AR pathway can promote skeletal muscle hypertrophy independent of ligand administration, and highlight novel methods for potentially modulating muscle mass in settings of disease.
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Kuwano Y, Adler M, Zhang H, Groisman A, Ley K. Gαi2 and Gαi3 Differentially Regulate Arrest from Flow and Chemotaxis in Mouse Neutrophils. THE JOURNAL OF IMMUNOLOGY 2016; 196:3828-33. [PMID: 26976957 DOI: 10.4049/jimmunol.1500532] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 02/22/2016] [Indexed: 01/13/2023]
Abstract
Leukocyte recruitment to inflammation sites progresses in a multistep cascade. Chemokines regulate multiple steps of the cascade, including arrest, transmigration, and chemotaxis. The most important chemokine receptor in mouse neutrophils is CXCR2, which couples through Gαi2- and Gαi3-containing heterotrimeric G proteins. Neutrophils arrest in response to CXCR2 stimulation. This is defective in Gαi2-deficient neutrophils. In this study, we show that Gαi3-deficient neutrophils showed reduced transmigration but normal arrest in mice. We also tested Gαi2- or Gαi3-deficient neutrophils in a CXCL1 gradient generated by a microfluidic device. Gαi3-, but not Gαi2-, deficient neutrophils showed significantly reduced migration and directionality. This was confirmed in a model of sterile inflammation in vivo. Gαi2-, but not Gαi3-, deficient neutrophils showed decreased Ca(2+) flux in response to CXCR2 stimulation. Conversely, Gαi3-, but not Gαi2-, deficient neutrophils exhibited reduced AKT phosphorylation upon CXCR2 stimulation. We conclude that Gαi2 controls arrest and Gαi3 controls transmigration and chemotaxis in response to chemokine stimulation of neutrophils.
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Affiliation(s)
- Yoshihiro Kuwano
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037
| | - Micha Adler
- Department of Physics, University of California, San Diego, La Jolla, CA 92093; and
| | - Hong Zhang
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037
| | - Alex Groisman
- Department of Physics, University of California, San Diego, La Jolla, CA 92093; and
| | - Klaus Ley
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037; Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
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Okamoto R, Watanabe M. Role of epithelial cells in the pathogenesis and treatment of inflammatory bowel disease. J Gastroenterol 2016; 51:11-21. [PMID: 26138071 DOI: 10.1007/s00535-015-1098-4] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 06/15/2015] [Indexed: 02/04/2023]
Abstract
In the past decades, continuous effort has been paid to deeply understanding the pathophysiology of inflammatory bowel diseases (IBD), such as ulcerative colitis or Crohn's disease. As the disease typically arises as chronic inflammation of the gastrointestinal mucosa, research has been focused on how such an uncontrolled, deleterious immune response may arise and persist in a certain cohort of patients. Based on those immunologic analyses, the establishment of anti-TNF-α therapy, and the following series of biologic agents achieved great success and dramatically changed the therapeutic strategy of IBD patients. However, to guarantee long-term remission of the disease, the therapeutic standard has been raised to achieve "mucosal healing", which requires complete repair of the gastrointestinal mucosa. Recent studies have revealed the unexpected importance of epithelial cells in the pathophysiology of IBD. The general barrier function as well as the cell lineage-specific functions have been deeply attributed to the development of chronic intestinal inflammation. Also, the groundbreaking establishment of the in vitro intestinal stem cell culture system has opened up a way of developing stem cell transplantation therapy to treat otherwise refractory ulcers that may persist in IBD patients. In this review, we would like to focus on the role of epithelial cells in the pathophysiology of IBD, and also give a perspective to the upcoming development of regenerative therapies that may become one of the therapeutic choices to achieve mucosal healing in refractory patients of IBD.
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Affiliation(s)
- Ryuichi Okamoto
- Center for Stem Cell and Regenerative Medicine, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-Ku, Tokyo, 113-8519, Japan.
| | - Mamoru Watanabe
- Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
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36
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Xie Z, Chan EC, Druey KM. R4 Regulator of G Protein Signaling (RGS) Proteins in Inflammation and Immunity. AAPS JOURNAL 2015; 18:294-304. [PMID: 26597290 DOI: 10.1208/s12248-015-9847-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/11/2015] [Indexed: 11/30/2022]
Abstract
G protein-coupled receptors (GPCRs) have important functions in both innate and adaptive immunity, with the capacity to bridge interactions between the two arms of the host responses to pathogens through direct recognition of secreted microbial products or the by-products of host cells damaged by pathogen exposure. In the mid-1990s, a large group of intracellular proteins was discovered, the regulator of G protein signaling (RGS) family, whose main, but not exclusive, function appears to be to constrain the intensity and duration of GPCR signaling. The R4/B subfamily--the focus of this review--includes RGS1-5, 8, 13, 16, 18, and 21, which are the smallest RGS proteins in size, with the exception of RGS3. Prominent roles in the trafficking of B and T lymphocytes and macrophages have been described for RGS1, RGS13, and RGS16, while RGS18 appears to control platelet and osteoclast functions. Additional G protein independent functions of RGS13 have been uncovered in gene expression in B lymphocytes and mast cell-mediated allergic reactions. In this review, we discuss potential physiological roles of this RGS protein subfamily, primarily in leukocytes having central roles in immune and inflammatory responses. We also discuss approaches to target RGS proteins therapeutically, which represents a virtually untapped strategy to combat exaggerated immune responses leading to inflammation.
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Affiliation(s)
- Zhihui Xie
- Molecular Signal Transduction Section, Laboratory of Allergic Diseases, NIAID/NIH, 50 South Drive Room 4154, Bethesda, Maryland, 20892, USA
| | - Eunice C Chan
- Molecular Signal Transduction Section, Laboratory of Allergic Diseases, NIAID/NIH, 50 South Drive Room 4154, Bethesda, Maryland, 20892, USA
| | - Kirk M Druey
- Molecular Signal Transduction Section, Laboratory of Allergic Diseases, NIAID/NIH, 50 South Drive Room 4154, Bethesda, Maryland, 20892, USA.
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Mizoguchi A, Takeuchi T, Himuro H, Okada T, Mizoguchi E. Genetically engineered mouse models for studying inflammatory bowel disease. J Pathol 2015; 238:205-19. [PMID: 26387641 DOI: 10.1002/path.4640] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/05/2015] [Accepted: 09/14/2015] [Indexed: 12/11/2022]
Abstract
Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory condition that is mediated by very complex mechanisms controlled by genetic, immune, and environmental factors. More than 74 kinds of genetically engineered mouse strains have been established since 1993 for studying IBD. Although mouse models cannot fully reflect human IBD, they have provided significant contributions for not only understanding the mechanism, but also developing new therapeutic means for IBD. Indeed, 20 kinds of genetically engineered mouse models carry the susceptibility genes identified in human IBD, and the functions of some other IBD susceptibility genes have also been dissected out using mouse models. Cutting-edge technologies such as cell-specific and inducible knockout systems, which were recently employed to mouse IBD models, have further enhanced the ability of investigators to provide important and unexpected rationales for developing new therapeutic strategies for IBD. In this review article, we briefly introduce 74 kinds of genetically engineered mouse models that spontaneously develop intestinal inflammation.
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Affiliation(s)
- Atsushi Mizoguchi
- Department of Immunology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
| | - Takahito Takeuchi
- Department of Immunology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
| | - Hidetomo Himuro
- Department of Immunology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
| | - Toshiyuki Okada
- Department of Immunology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
| | - Emiko Mizoguchi
- Gastrointestinal Unit and Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital, Harvard Medical School, Fruit Street, Boston, MA, 02114, USA
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Keller K, Maass M, Dizayee S, Leiss V, Annala S, Köth J, Seemann WK, Müller-Ehmsen J, Mohr K, Nürnberg B, Engelhardt S, Herzig S, Birnbaumer L, Matthes J. Lack of Gαi2 leads to dilative cardiomyopathy and increased mortality in β1-adrenoceptor overexpressing mice. Cardiovasc Res 2015; 108:348-56. [PMID: 26464333 DOI: 10.1093/cvr/cvv235] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 09/28/2015] [Indexed: 01/05/2023] Open
Abstract
AIMS Inhibitory G (Gi) proteins have been proposed to be cardioprotective. We investigated effects of Gαi2 knockout on cardiac function and survival in a murine heart failure model of cardiac β1-adrenoceptor overexpression. METHODS AND RESULTS β1-transgenic mice lacking Gαi2 (β1-tg/Gαi2 (-/-)) were compared with wild-type mice and littermates either overexpressing cardiac β1-adrenoceptors (β1-tg) or lacking Gαi2 (Gαi2 (-/-)). At 300 days, mortality of mice only lacking Gαi2 was already higher compared with wild-type or β1-tg, but similar to β1-tg/Gαi2 (-/-), mice. Beyond 300 days, mortality of β1-tg/Gαi2 (-/-) mice was enhanced compared with all other genotypes (mean survival time: 363 ± 21 days). At 300 days of age, echocardiography revealed similar cardiac function of wild-type, β1-tg, and Gαi2 (-/-) mice, but significant impairment for β1-tg/Gαi2 (-/-) mice (e.g. ejection fraction 14 ± 2 vs. 40 ± 4% in wild-type mice). Significantly increased ventricle-to-body weight ratio (0.71 ± 0.06 vs. 0.48 ± 0.02% in wild-type mice), left ventricular size (length 0.82 ± 0.04 vs. 0.66 ± 0.03 cm in wild types), and atrial natriuretic peptide and brain natriuretic peptide expression (mRNA: 2819 and 495% of wild-type mice, respectively) indicated hypertrophy. Gαi3 was significantly up-regulated in Gαi2 knockout mice (protein compared with wild type: 340 ± 90% in Gαi2 (-/-) and 394 ± 80% in β1-tg/Gαi2 (-/-), respectively). CONCLUSIONS Gαi2 deficiency combined with cardiac β1-adrenoceptor overexpression strongly impaired survival and cardiac function. At 300 days of age, β1-adrenoceptor overexpression alone had not induced cardiac hypertrophy or dysfunction while there was overt cardiomyopathy in mice additionally lacking Gαi2. We propose an enhanced effect of increased β1-adrenergic drive by the lack of protection via Gαi2. Gαi3 up-regulation was not sufficient to compensate for Gαi2 deficiency, suggesting an isoform-specific or a concentration-dependent mechanism.
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Affiliation(s)
- Kirsten Keller
- Department of Pharmacology, University of Cologne, Gleueler Strasse 24, 50931 Cologne, Germany
| | - Martina Maass
- Department of Internal Medicine III, University Hospital of Cologne, Cologne, Germany
| | - Sara Dizayee
- Department of Pharmacology, University of Cologne, Gleueler Strasse 24, 50931 Cologne, Germany
| | - Veronika Leiss
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, Tuebingen, Germany
| | - Suvi Annala
- Department of Pharmacology, University of Cologne, Gleueler Strasse 24, 50931 Cologne, Germany
| | - Jessica Köth
- Department of Pharmacology, University of Cologne, Gleueler Strasse 24, 50931 Cologne, Germany
| | - Wiebke K Seemann
- Department of Pharmacology, University of Cologne, Gleueler Strasse 24, 50931 Cologne, Germany
| | | | - Klaus Mohr
- Pharmacology and Toxicology Section, Institute of Pharmacy, University of Bonn, Bonn, Germany
| | - Bernd Nürnberg
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, Tuebingen, Germany
| | - Stefan Engelhardt
- Institute of Pharmacology and Toxicology, Technische Universität München, Munich, Germany
| | - Stefan Herzig
- Department of Pharmacology, University of Cologne, Gleueler Strasse 24, 50931 Cologne, Germany
| | - Lutz Birnbaumer
- Laboratory of Neurobiology, NIEHS, NIH (Department of Health and Human Services), Durham, USA
| | - Jan Matthes
- Department of Pharmacology, University of Cologne, Gleueler Strasse 24, 50931 Cologne, Germany
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AKT-independent Reelin signaling requires interactions of heterotrimeric Go and Src. Biochem Biophys Res Commun 2015; 467:1063-9. [PMID: 26441085 DOI: 10.1016/j.bbrc.2015.09.167] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 09/30/2015] [Indexed: 11/23/2022]
Abstract
Reelin, a large secreted extracellular matrix glycoprotein, plays a key role in neuronal migration during cortical development and promotes neuronal maturation. The signaling pathway regulating neuronal maturation in the postnatal period are relatively less well understood. In this study, we demonstrated that a heterotrimeric G protein, Go, is a novel target of Reelin-induced signaling to promote neurite outgrowth. In primary hippocampal neurons of Reelin-deficient reeler mice, neurite outgrowth was significantly reduced and rescued upon addition of Reelin. Pertussis toxin (PTX) treatment or transfection with Gαo-siRNA suppressed Reelin-mediated neurite outgrowth in wild-type neurons. Additionally, Reelin treatment led to increased phosphorylation of AKT, GSK3β, and JNK, which were all effectively blocked by the PI3K inhibitor, LY294002. By comparison, PTX specifically blocked JNK activation, but not AKT and GSK3β. Immunoprecipitation assays disclosed that Reelin increases the active forms of both Src and Gαo and promotes their direct association. Notably, Dab1, a cytoplasmic adaptor molecule that mediates Reelin signaling, did not interact with Gαo. Neurite outgrowth by Reelin was induced via activating Src kinase, which directly stimulated Gαo, activity, leading to JNK activation. Based on the collective findings, we suggest that Reelin-dependent signaling mechanisms may be split into Src-AKT-dependent and Src-Go-dependent pathways. Our results additionally provide evidence that Reelin receptors cross-communicate with heterologous G protein-coupled receptors (GPCR) independently of the cognate ligands of GPCR.
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Hillgruber C, Pöppelmann B, Weishaupt C, Steingräber AK, Wessel F, Berdel WE, Gessner JE, Ho-Tin-Noé B, Vestweber D, Goerge T. Blocking neutrophil diapedesis prevents hemorrhage during thrombocytopenia. ACTA ACUST UNITED AC 2015; 212:1255-66. [PMID: 26169941 PMCID: PMC4516803 DOI: 10.1084/jem.20142076] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 06/11/2015] [Indexed: 01/03/2023]
Abstract
Organ hemorrhage represents a major complication in thrombocytopenia with potential fatal outcome. Hillgruber et al. demonstrate that neutrophil diapedesis through the endothelial barrier is responsible for the bleeding and could represent a therapeutic target in immune-thrombocytopenic patients. Spontaneous organ hemorrhage is the major complication in thrombocytopenia with a potential fatal outcome. However, the exact mechanisms regulating vascular integrity are still unknown. Here, we demonstrate that neutrophils recruited to inflammatory sites are the cellular culprits inducing thrombocytopenic tissue hemorrhage. Exposure of thrombocytopenic mice to UVB light provokes cutaneous petechial bleeding. This phenomenon is also observed in immune-thrombocytopenic patients when tested for UVB tolerance. Mechanistically, we show, analyzing several inflammatory models, that it is neutrophil diapedesis through the endothelial barrier that is responsible for the bleeding defect. First, bleeding is triggered by neutrophil-mediated mechanisms, which act downstream of capturing, adhesion, and crawling on the blood vessel wall and require Gαi signaling in neutrophils. Second, mutating Y731 in the cytoplasmic tail of VE-cadherin, known to selectively affect leukocyte diapedesis, but not the induction of vascular permeability, attenuates bleeding. Third, and in line with this, simply destabilizing endothelial junctions by histamine did not trigger bleeding. We conclude that specifically targeting neutrophil diapedesis through the endothelial barrier may represent a new therapeutic avenue to prevent fatal bleeding in immune-thrombocytopenic patients.
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Affiliation(s)
- Carina Hillgruber
- Department of Dermatology and Department of Medicine A-Hematology and Oncology, University Hospital of Münster and Interdisciplinary Center for Clinical Research (IZKF), University of Münster, 48149 Münster, Germany Department of Dermatology and Department of Medicine A-Hematology and Oncology, University Hospital of Münster and Interdisciplinary Center for Clinical Research (IZKF), University of Münster, 48149 Münster, Germany
| | - Birgit Pöppelmann
- Department of Dermatology and Department of Medicine A-Hematology and Oncology, University Hospital of Münster and Interdisciplinary Center for Clinical Research (IZKF), University of Münster, 48149 Münster, Germany
| | - Carsten Weishaupt
- Department of Dermatology and Department of Medicine A-Hematology and Oncology, University Hospital of Münster and Interdisciplinary Center for Clinical Research (IZKF), University of Münster, 48149 Münster, Germany
| | - Annika Kathrin Steingräber
- Department of Dermatology and Department of Medicine A-Hematology and Oncology, University Hospital of Münster and Interdisciplinary Center for Clinical Research (IZKF), University of Münster, 48149 Münster, Germany
| | - Florian Wessel
- Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany
| | - Wolfgang E Berdel
- Department of Dermatology and Department of Medicine A-Hematology and Oncology, University Hospital of Münster and Interdisciplinary Center for Clinical Research (IZKF), University of Münster, 48149 Münster, Germany
| | - J Engelbert Gessner
- Clinical Department of Immunology and Rheumatology, Molecular Immunology Research Unit, Hannover Medical School, 30625 Hannover, Germany
| | - Benoît Ho-Tin-Noé
- French Institute of Health and Medical Research (INSERM) U1148-Paris 7 University, Xavier Bichat Hospital, 75877 Paris, France
| | - Dietmar Vestweber
- Department of Vascular Cell Biology, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany
| | - Tobias Goerge
- Department of Dermatology and Department of Medicine A-Hematology and Oncology, University Hospital of Münster and Interdisciplinary Center for Clinical Research (IZKF), University of Münster, 48149 Münster, Germany Department of Dermatology and Department of Medicine A-Hematology and Oncology, University Hospital of Münster and Interdisciplinary Center for Clinical Research (IZKF), University of Münster, 48149 Münster, Germany
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Inhibition of G-Protein βγ Signaling Decreases Levels of Messenger RNAs Encoding Proinflammatory Cytokines in T Cell Receptor-Stimulated CD4(+) T Helper Cells. J Mol Signal 2015; 10:1. [PMID: 27095999 PMCID: PMC4831316 DOI: 10.5334/1750-2187-10-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Background: Inhibition of G-protein βγ (Gβγ) signaling was found previously to enhance T cell receptor (TCR)-stimulated increases in interleukin 2 (IL-2) mRNA in CD4+ T helper cells, suggesting that Gβγ might be a useful drug target for treating autoimmune diseases, as low dose IL-2 therapy can suppress autoimmune responses. Because IL-2 may counteract autoimmunity in part by shifting CD4+ T helper cells away from the Type 1 T helper cell (TH1) and TH17 subtypes towards the TH2 subtype, the purpose of this study was to determine if blocking Gβγ signaling affected the balance of TH1, TH17, and TH2 cytokine mRNAs produced by CD4+ T helper cells. Methods: Gallein, a small molecule inhibitor of Gβγ, and siRNA-mediated silencing of the G-protein β1 subunit (Gβ1) were used to test the effect of blocking Gβγ on mRNA levels of cytokines in primary human TCR-stimulated CD4+ T helper cells. Results: Gallein and Gβ1 siRNA decreased interferon-γ (IFN-γ) and IL-17A mRNA levels in TCR-stimulated CD4+ T cells grown under TH1-promoting conditions. Inhibiting Gβγ also decreased mRNA levels of STAT4, which plays a positive role in TH1 differentiation and IL-17A production. Moreover, mRNA levels of the STAT4-regulated TH1-associated proteins, IL-18 receptor β chain (IL-18Rβ), mitogen-activated protein kinase kinase kinase 8 (MAP3K8), lymphocyte activation gene 3 (LAG-3), natural killer cell group 7 sequence (NKG7), and oncostatin M (OSM) were also decreased upon Gβγ inhibition. Gallein also increased IL-4, IL-5, IL-9, and IL-13 mRNA levels in TCR-stimulated memory CD4+ T cells grown in TH2-promoting conditions. Conclusions: Inhibiting Gβγ to produce these shifts in cytokine mRNA production might be beneficial for patients with autoimmune diseases such as rheumatoid arthritis (RA), Crohn’s disease (CD), psoriasis, multiple sclerosis (MS), and Hashimoto’s thyroiditis (HT), in which both IFN-γ and IL-17A are elevated.
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Valatas V, Bamias G, Kolios G. Experimental colitis models: Insights into the pathogenesis of inflammatory bowel disease and translational issues. Eur J Pharmacol 2015; 759:253-64. [DOI: 10.1016/j.ejphar.2015.03.017] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 02/03/2015] [Accepted: 03/12/2015] [Indexed: 02/06/2023]
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Platelet Gi protein Gαi2 is an essential mediator of thrombo-inflammatory organ damage in mice. Proc Natl Acad Sci U S A 2015; 112:6491-6. [PMID: 25944935 DOI: 10.1073/pnas.1505887112] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Platelets are crucial for hemostasis and thrombosis and exacerbate tissue injury following ischemia and reperfusion. Important regulators of platelet function are G proteins controlled by seven transmembrane receptors. The Gi protein Gα(i2) mediates platelet activation in vitro, but its in vivo role in hemostasis, arterial thrombosis, and postischemic infarct progression remains to be determined. Here we show that mice lacking Gα(i2) exhibit prolonged tail-bleeding times and markedly impaired thrombus formation and stability in different models of arterial thrombosis. We thus generated mice selectively lacking Gα(i2) in megakaryocytes and platelets (Gna(i2)(fl/fl)/PF4-Cre mice) and found bleeding defects comparable to those in global Gα(i2)-deficient mice. To examine the impact of platelet Gα(i2) in postischemic thrombo-inflammatory infarct progression, Gna(i2)(fl/fl)/PF4-Cre mice were subjected to experimental models of cerebral and myocardial ischemia/reperfusion injury. In the model of transient middle cerebral artery occlusion stroke Gna(i2)(fl/fl)/PF4-Cre mice developed significantly smaller brain infarcts and fewer neurological deficits than littermate controls. Following myocardial ischemia, Gna(i2)(fl/fl)/PF4-Cre mice showed dramatically reduced reperfusion injury which correlated with diminished formation of the ADP-dependent platelet neutrophil complex. In conclusion, our data provide definitive evidence that platelet Gα(i2) not only controls hemostatic and thrombotic responses but also is critical for the development of ischemia/reperfusion injury in vivo.
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44
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Gαi1 and Gαi3 regulate macrophage polarization by forming a complex containing CD14 and Gab1. Proc Natl Acad Sci U S A 2015; 112:4731-6. [PMID: 25825741 DOI: 10.1073/pnas.1503779112] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Heterotrimeric G proteins have been implicated in Toll-like receptor 4 (TLR4) signaling in macrophages and endothelial cells. However, whether guanine nucleotide-binding protein G(i) subunit alpha-1 and alpha-3 (Gαi1/3) are required for LPS responses remains unclear, and if so, the underlying mechanisms need to be studied. In this study, we demonstrated that, in response to LPS, Gαi1/3 form complexes containing the pattern recognition receptor (PRR) CD14 and growth factor receptor binding 2 (Grb2)-associated binding protein (Gab1), which are required for activation of PI3K-Akt signaling. Gαi1/3 deficiency decreased LPS-induced TLR4 endocytosis, which was associated with decreased phosphorylation of IFN regulatory factor 3 (IRF3). Gαi1/3 knockdown in bone marrow-derived macrophage cells (Gαi1/3 KD BMDMs) exhibited an M2-like phenotype with significantly suppressed production of TNF-α, IL-6, IL-12, and NO in response to LPS. The altered polarization coincided with decreased Akt activation. Further, Gαi1/3 deficiency caused LPS tolerance in mice. In vitro studies revealed that, in LPS-tolerant macrophages, Gαi1/3 were down-regulated partially by the proteasome pathway. Collectively, the present findings demonstrated that Gαi1/3 can interact with CD14/Gab1, which modulates macrophage polarization in vitro and in vivo.
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45
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Leiss V, Flockerzie K, Novakovic A, Rath M, Schönsiegel A, Birnbaumer L, Schürmann A, Harteneck C, Nürnberg B. Insulin secretion stimulated by L-arginine and its metabolite L-ornithine depends on Gα(i2). Am J Physiol Endocrinol Metab 2014; 307:E800-12. [PMID: 25205820 PMCID: PMC4216945 DOI: 10.1152/ajpendo.00337.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bordetella pertussis toxin (PTx), also known as islet-activating protein, induces insulin secretion by ADP-ribosylation of inhibitory G proteins. PTx-induced insulin secretion may result either from inactivation of Gα(o) proteins or from combined inactivation of Gα(o), Gα(i1), Gα(i2), and Gα(i3) isoforms. However, the specific role of Gα(i2) in pancreatic β-cells still remains unknown. In global (Gα(i2)(-/-)) and β-cell-specific (Gα(i2)(βcko)) gene-targeted Gα(i2) mouse models, we studied glucose homeostasis and islet functions. Insulin secretion experiments and intracellular Ca²⁺ measurements were used to characterize Gα(i2) function in vitro. Gα(i2)(-/-) and Gα(i2)(βcko) mice showed an unexpected metabolic phenotype, i.e., significantly lower plasma insulin levels upon intraperitoneal glucose challenge in Gα(i2)(-/-) and Gα(i2)(βcko) mice, whereas plasma glucose concentrations were unchanged in Gα(i2)(-/-) but significantly increased in Gα(i2)(βcko) mice. These findings indicate a novel albeit unexpected role for Gα(i2) in the expression, turnover, and/or release of insulin from islets. Detection of insulin secretion in isolated islets did not show differences in response to high (16 mM) glucose concentrations between control and β-cell-specific Gα(i2)-deficient mice. In contrast, the two- to threefold increase in insulin secretion evoked by L-arginine or L-ornithine (in the presence of 16 mM glucose) was significantly reduced in islets lacking Gα(i2). In accord with a reduced level of insulin secretion, intracellular calcium concentrations induced by the agonistic amino acid L-arginine did not reach control levels in β-cells. The presented analysis of gene-targeted mice provides novel insights in the role of β-cell Gα(i2) showing that amino acid-induced insulin-release depends on Gα(i2).
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MESH Headings
- Animals
- Arginine/metabolism
- Blood Glucose/analysis
- Calcium Signaling
- Crosses, Genetic
- Down-Regulation
- Fluorescent Antibody Technique
- GTP-Binding Protein alpha Subunit, Gi2/agonists
- GTP-Binding Protein alpha Subunit, Gi2/genetics
- GTP-Binding Protein alpha Subunit, Gi2/metabolism
- GTP-Binding Protein alpha Subunits, Gi-Go/agonists
- GTP-Binding Protein alpha Subunits, Gi-Go/genetics
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Hyperglycemia/blood
- Hyperglycemia/metabolism
- Hyperglycemia/prevention & control
- Hypoglycemia/blood
- Hypoglycemia/metabolism
- Hypoglycemia/prevention & control
- Insulin/blood
- Insulin/metabolism
- Insulin Secretion
- Islets of Langerhans/cytology
- Islets of Langerhans/metabolism
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Ornithine/blood
- Ornithine/metabolism
- Specific Pathogen-Free Organisms
- Tissue Culture Techniques
- Up-Regulation
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Affiliation(s)
- Veronika Leiss
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany
| | - Katarina Flockerzie
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany
| | - Ana Novakovic
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany
| | - Michaela Rath
- Department of Experimental Diabetology, German Institute of Human Nutrition, Potsdam-Rehbrücke, Nuthetal, Germany
| | - Annika Schönsiegel
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany
| | - Lutz Birnbaumer
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health/Department of Health and Human Services, Durham, North Carolina
| | - Annette Schürmann
- Department of Experimental Diabetology, German Institute of Human Nutrition, Potsdam-Rehbrücke, Nuthetal, Germany
| | - Christian Harteneck
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany
| | - Bernd Nürnberg
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany;
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46
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Canonical and noncanonical g-protein signaling helps coordinate actin dynamics to promote macrophage phagocytosis of zymosan. Mol Cell Biol 2014; 34:4186-99. [PMID: 25225330 DOI: 10.1128/mcb.00325-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Both chemotaxis and phagocytosis depend upon actin-driven cell protrusions and cell membrane remodeling. While chemoattractant receptors rely upon canonical G-protein signaling to activate downstream effectors, whether such signaling pathways affect phagocytosis is contentious. Here, we report that Gαi nucleotide exchange and signaling helps macrophages coordinate the recognition, capture, and engulfment of zymosan bioparticles. We show that zymosan exposure recruits F-actin, Gαi proteins, and Elmo1 to phagocytic cups and early phagosomes. Zymosan triggered an increase in intracellular Ca(2+) that was partially sensitive to Gαi nucleotide exchange inhibition and expression of GTP-bound Gαi recruited Elmo1 to the plasma membrane. Reducing GDP-Gαi nucleotide exchange, decreasing Gαi expression, pharmacologically interrupting Gβγ signaling, or reducing Elmo1 expression all impaired phagocytosis, while favoring the duration that Gαi remained GTP bound promoted it. Our studies demonstrate that targeting heterotrimeric G-protein signaling offers opportunities to enhance or retard macrophage engulfment of phagocytic targets such as zymosan.
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47
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Animal models of inflammatory bowel disease: a review. Inflammopharmacology 2014; 22:219-33. [PMID: 24906689 DOI: 10.1007/s10787-014-0207-y] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 05/09/2014] [Indexed: 02/06/2023]
Abstract
Inflammatory bowel disease (IBD) represents a group of idiopathic chronic inflammatory intestinal conditions associated with various areas of the GI tract, including two types of inflammatory conditions, i.e., ulcerative colitis (UC) and Crohn's disease (CD). Both UC and CD are chronic inflammatory disorders of the intestine; in UC, inflammation starts in the rectum and generally extends proximally in a continuous manner through the entire colon. Bloody diarrhea, presence of blood and mucus mixed with stool, accompanied by lower abdominal cramping, are the characteristic symptoms of the disease. While in CD, inflammatory condition may affect any part of the GI tract from mouth to anus. It mainly causes abdominal pain, diarrhea, vomiting and weight loss. Although the basic etiology of IBD is unknown, there are several factors that may contribute to the pathogenesis of this disease, such as dysregulation of immune system or commensal bacteria, oxidative stress and inflammatory mediators. In order to understand these different etiological factors, a number of experimental models are available in the scientific research, including chemical-induced, spontaneous, genetically engineered and transgenic models. These models represent a major source of information about biological systems and are clinically relevant to the human IBD. Since there is less collective data available in one single article discussing about all these models, in this review an effort is made to study the outline of pathophysiology and various types of animal models used in the research study of IBD and other disease-related complications.
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48
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Köhler D, Devanathan V, Bernardo de Oliveira Franz C, Eldh T, Novakovic A, Roth JM, Granja T, Birnbaumer L, Rosenberger P, Beer-Hammer S, Nürnberg B. Gαi2- and Gαi3-deficient mice display opposite severity of myocardial ischemia reperfusion injury. PLoS One 2014; 9:e98325. [PMID: 24858945 PMCID: PMC4032280 DOI: 10.1371/journal.pone.0098325] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 04/30/2014] [Indexed: 12/19/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) are the most abundant receptors in the heart and therefore are common targets for cardiovascular therapeutics. The activated GPCRs transduce their signals via heterotrimeric G-proteins. The four major families of G-proteins identified so far are specified through their α-subunit: Gαi, Gαs, Gαq and G12/13. Gαi-proteins have been reported to protect hearts from ischemia reperfusion injury. However, determining the individual impact of Gαi2 or Gαi3 on myocardial ischemia injury has not been clarified yet. Here, we first investigated expression of Gαi2 and Gαi3 on transcriptional level by quantitative PCR and on protein level by immunoblot analysis as well as by immunofluorescence in cardiac tissues of wild-type, Gαi2-, and Gαi3-deficient mice. Gαi2 was expressed at higher levels than Gαi3 in murine hearts, and irrespective of the isoform being knocked out we observed an up regulation of the remaining Gαi-protein. Myocardial ischemia promptly regulated cardiac mRNA and with a slight delay protein levels of both Gαi2 and Gαi3, indicating important roles for both Gαi isoforms. Furthermore, ischemia reperfusion injury in Gαi2- and Gαi3-deficient mice exhibited opposite outcomes. Whereas the absence of Gαi2 significantly increased the infarct size in the heart, the absence of Gαi3 or the concomitant upregulation of Gαi2 dramatically reduced cardiac infarction. In conclusion, we demonstrate for the first time that the genetic ablation of Gαi proteins has protective or deleterious effects on cardiac ischemia reperfusion injury depending on the isoform being absent.
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Affiliation(s)
- David Köhler
- Department of Anesthesiology and Intensive Care Medicine, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, Tuebingen, Germany
| | - Vasudharani Devanathan
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, Tuebingen, Germany
| | - Claudia Bernardo de Oliveira Franz
- Department of Anesthesiology and Intensive Care Medicine, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, Tuebingen, Germany
| | - Therese Eldh
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, Tuebingen, Germany
| | - Ana Novakovic
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, Tuebingen, Germany
| | - Judith M. Roth
- Department of Anesthesiology and Intensive Care Medicine, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, Tuebingen, Germany
| | - Tiago Granja
- Department of Anesthesiology and Intensive Care Medicine, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, Tuebingen, Germany
| | - Lutz Birnbaumer
- Laboratory of Neurobiology, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, United States of America
| | - Peter Rosenberger
- Department of Anesthesiology and Intensive Care Medicine, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, Tuebingen, Germany
| | - Sandra Beer-Hammer
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, Tuebingen, Germany
- * E-mail: (SBH); (BN)
| | - Bernd Nürnberg
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Drug Research, Tuebingen, Germany
- * E-mail: (SBH); (BN)
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49
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Boularan C, Kehrl JH. Implications of non-canonical G-protein signaling for the immune system. Cell Signal 2014; 26:1269-82. [PMID: 24583286 DOI: 10.1016/j.cellsig.2014.02.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 02/22/2014] [Indexed: 01/13/2023]
Abstract
Heterotrimeric guanine nucleotide-binding proteins (G proteins), which consist of three subunits α, β, and γ, function as molecular switches to control downstream effector molecules activated by G protein-coupled receptors (GPCRs). The GTP/GDP binding status of Gα transmits information about the ligand binding state of the GPCR to intended signal transduction pathways. In immune cells heterotrimeric G proteins impact signal transduction pathways that directly, or indirectly, regulate cell migration, activation, survival, proliferation, and differentiation. The cells of the innate and adaptive immune system abundantly express chemoattractant receptors and lesser amounts of many other types of GPCRs. But heterotrimeric G-proteins not only function in classical GPCR signaling, but also in non-canonical signaling. In these pathways the guanine exchange factor (GEF) exerted by a GPCR in the canonical pathway is replaced or supplemented by another protein such as Ric-8A. In addition, other proteins such as AGS3-6 can compete with Gβγ for binding to GDP bound Gα. This competition can promote Gβγ signaling by freeing Gβγ from rapidly rebinding GDP bound Gα. The proteins that participate in these non-canonical signaling pathways will be briefly described and their role, or potential one, in cells of the immune system will be highlighted.
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Affiliation(s)
- Cédric Boularan
- B-cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, United States
| | - John H Kehrl
- B-cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, United States.
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50
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Branham-O'Connor M, Robichaux WG, Zhang XK, Cho H, Kehrl JH, Lanier SM, Blumer JB. Defective chemokine signal integration in leukocytes lacking activator of G protein signaling 3 (AGS3). J Biol Chem 2014; 289:10738-10747. [PMID: 24573680 DOI: 10.1074/jbc.m113.515031] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activator of G-protein signaling 3 (AGS3, gene name G-protein signaling modulator-1, Gpsm1), an accessory protein for G-protein signaling, has functional roles in the kidney and CNS. Here we show that AGS3 is expressed in spleen, thymus, and bone marrow-derived dendritic cells, and is up-regulated upon leukocyte activation. We explored the role of AGS3 in immune cell function by characterizing chemokine receptor signaling in leukocytes from mice lacking AGS3. No obvious differences in lymphocyte subsets were observed. Interestingly, however, AGS3-null B and T lymphocytes and bone marrow-derived dendritic cells exhibited significant chemotactic defects as well as reductions in chemokine-stimulated calcium mobilization and altered ERK and Akt activation. These studies indicate a role for AGS3 in the regulation of G-protein signaling in the immune system, providing unexpected venues for the potential development of therapeutic agents that modulate immune function by targeting these regulatory mechanisms.
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Affiliation(s)
- Melissa Branham-O'Connor
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425
| | - William G Robichaux
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Xian-Kui Zhang
- Department of Medicine, Division of Rheumatology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Hyeseon Cho
- B-cell Section, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - John H Kehrl
- B-cell Section, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - Stephen M Lanier
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Joe B Blumer
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina 29425.
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