RGS13 controls g protein-coupled receptor-evoked responses of human mast cells

J Immunol. 2008 Dec 1;181(11):7882-90. doi: 10.4049/jimmunol.181.11.7882.

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.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Adenosine / immunology
  • Adenosine / pharmacology
  • Allergens / genetics
  • Allergens / immunology
  • Allergens / pharmacology
  • Anaphylaxis / genetics
  • Anaphylaxis / immunology
  • Animals
  • Antigens / genetics
  • Antigens / immunology
  • Antigens / pharmacology
  • Calcium / immunology
  • Cell Degranulation / drug effects
  • Cell Degranulation / genetics
  • Cell Degranulation / immunology*
  • Cell Line
  • Chemokine CXCL12 / immunology
  • Chemokine CXCL12 / pharmacology
  • Chemotaxis / drug effects
  • Chemotaxis / genetics
  • Chemotaxis / immunology
  • Complement C5a / immunology
  • Complement C5a / pharmacology
  • Humans
  • Immunoglobulin E / immunology
  • Immunoglobulin E / pharmacology
  • Interleukin-8 / genetics
  • Interleukin-8 / immunology
  • Ligands
  • Lysophospholipids / immunology
  • Lysophospholipids / pharmacology
  • Mast Cells / immunology*
  • Mice
  • Phosphorylation / drug effects
  • Phosphorylation / genetics
  • Phosphorylation / immunology
  • Proto-Oncogene Proteins c-akt / genetics
  • Proto-Oncogene Proteins c-akt / immunology
  • RGS Proteins / antagonists & inhibitors
  • RGS Proteins / genetics
  • RGS Proteins / immunology*
  • RNA, Small Interfering / genetics
  • Receptors, G-Protein-Coupled / agonists
  • Receptors, G-Protein-Coupled / genetics
  • Receptors, G-Protein-Coupled / immunology
  • Sphingosine / analogs & derivatives
  • Sphingosine / immunology
  • Sphingosine / pharmacology

Substances

  • Allergens
  • Antigens
  • CXCL12 protein, human
  • CXCL8 protein, human
  • Chemokine CXCL12
  • Interleukin-8
  • Ligands
  • Lysophospholipids
  • RGS Proteins
  • RGS13 protein, human
  • RNA, Small Interfering
  • Receptors, G-Protein-Coupled
  • sphingosine 1-phosphate
  • Immunoglobulin E
  • Complement C5a
  • Proto-Oncogene Proteins c-akt
  • Adenosine
  • Sphingosine
  • Calcium