title: RGS13 controls g protein-coupled receptor-evoked responses of human mast cells.
abstract: IgE-mediated mast cell degranulation and release of vasoactive mediators induced by allergens elicits allergic responses. Although G protein-coupled receptor (GPCR)-induced signals may amplify IgE-dependent degranulation, how GPCR signaling in mast cells is regulated remains incompletely defined. We investigated the role of regulator of G protein signaling (RGS) proteins in the modulation of these pathways in human mast cells. Several RGS proteins were expressed in mast cells including RGS13, which we previously showed inhibited IgE-mediated mast cell degranulation and anaphylaxis in mice. To characterize how RGS13 affects GPCR-mediated functions of human mast cells, we analyzed human mast cell lines (HMC-1 and LAD2) depleted of RGS13 by specific small interfering RNA or short hairpin RNA and HMC-1 cells overexpressing RGS13. Transient RGS13 knockdown in LAD2 cells lead to increased degranulation to sphingosine-1-phosphate but not to IgE-Ag or C3a. Relative to control cells, HMC-1 cells stably expressing RGS13-targeted short hairpin RNA had greater Ca(2+) mobilization in response to several natural GPCR ligands such as adenosine, C5a, sphingosine-1-phosphate, and CXCL12 than wild-type cells. Akt phosphorylation, chemotaxis, and cytokine (IL-8) secretion induced by CXCL12 were also greater in short hairpin RGS13-HMC-1 cells compared with control. RGS13 overexpression inhibited CXCL12-evoked Ca(2+) mobilization, Akt phosphorylation and chemotaxis. These results suggest that RGS13 restricts certain GPCR-mediated biological responses of human mast cells.
authors.affiliation: Molecular Signal Transduction Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Geetanjali
authors.initials: G
authors.lastname: Bansal
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: DiVietro
authors.forename: Hye Sun
authors.initials: HS
authors.lastname: Kuehn
authors.forename: Sudhir
authors.initials: S
authors.lastname: Rao
authors.forename: Karl H
authors.initials: KH
authors.lastname: Nocka
authors.forename: Alasdair M
authors.initials: AM
authors.lastname: Gilfillan
authors.forename: Kirk M
authors.initials: KM
authors.lastname: Druey
mesh_terms: D000241:Adenosine / Q000276:immunology / Q000494:pharmacology; D000485:Allergens / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D000707:Anaphylaxis / Q000235:genetics / Q000276:immunology; D000818:Animals; D000941:Antigens / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D002118:Calcium / Q000276:immunology; D015550:Cell Degranulation / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D002460:Cell Line; D054377:Chemokine CXCL12 / Q000276:immunology / Q000494:pharmacology; D002633:Chemotaxis / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D015936:Complement C5a / Q000276:immunology / Q000494:pharmacology; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology / Q000494:pharmacology; D016209:Interleukin-8 / Q000235:genetics / Q000276:immunology; D008024:Ligands; D008246:Lysophospholipids / Q000276:immunology / Q000494:pharmacology; D008407:Mast Cells / Q000276:immunology*; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000276:immunology; D020710:RGS Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology*; D034741:RNA, Small Interfering / Q000235:genetics; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000235:genetics / Q000276:immunology; D013110:Sphingosine / Q000031:analogs & derivatives / Q000276:immunology / Q000494:pharmacology
chemical_list: D000485:Allergens; D000941:Antigens; C515255:CXCL12 protein, human; C508606:CXCL8 protein, human; D054377:Chemokine CXCL12; D016209:Interleukin-8; D008024:Ligands; D008246:Lysophospholipids; D020710:RGS Proteins; C456322:RGS13 protein, human; D034741:RNA, Small Interfering; D043562:Receptors, G-Protein-Coupled; C060506:sphingosine 1-phosphate; D007073:Immunoglobulin E; D015936:Complement C5a; D051057:Proto-Oncogene Proteins c-akt; D000241:Adenosine; D013110:Sphingosine; D002118:Calcium