title: Crosstalk between the alpha2beta1 integrin and c-met/HGF-R regulates innate immunity.
abstract: Data from several investigators suggest that the alpha2beta1 integrin, a receptor for collagens, laminins, decorin, E-cadherin, matrix metalloproteinase-1, endorepellin, and several viruses, is required for innate immunity and regulation of autoimmune/allergic disorders. We demonstrated that the innate immune response to Listeria monocytogenes required alpha2beta1 integrin expression by peritoneal mast cells (PMCs). Ligation of the alpha2beta1 integrin by C1q contained in immune complexes comprised of Listeria and antibody was required for PMC activation in vitro and in vivo. However, ligation of the alpha2beta1 integrin alone was insufficient to activate cytokine secretion, suggesting that one or more additional signals emanating from a coreceptor were required for PMC activation. Here, we demonstrate that C1q, but neither other complement proteins nor FcRgamma, is required for early innate immune response to Listeria. The binding of Listeria's Internalin B (InlB) to hepatocyte growth factor receptor (HGF-R)/c-met provides the costimulatory function required for PMC activation. Either HGF or Listeria InlB bound to c-met and either C1q or type I collagen bound to alpha2beta1 integrin stimulates PMC activation. These findings suggest that crosstalk between c-met and the alpha2beta1 integrin may contribute to mast-cell activation in autoimmune and inflammatory disorders.
authors.affiliation: Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232-2561, USA.
authors.forename: Karissa D
authors.initials: KD
authors.lastname: McCall-Culbreath
authors.forename: Zhengzhi
authors.initials: Z
authors.lastname: Li
authors.forename: Mary M
authors.initials: MM
authors.lastname: Zutter
mesh_terms: D000818:Animals; D001327:Autoimmune Diseases / Q000235:genetics / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology; D015922:Complement C1q / Q000235:genetics / Q000276:immunology; D016207:Cytokines / Q000235:genetics / Q000276:immunology; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000276:immunology; D007113:Immunity, Innate / Q000502:physiology*; D007152:Immunologic Capping / Q000276:immunology; D007249:Inflammation / Q000235:genetics / Q000276:immunology; D039421:Integrin alpha2 / Q000235:genetics / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008089:Listeria monocytogenes / Q000276:immunology*; D008088:Listeriosis / Q000235:genetics / Q000276:immunology*; D008407:Mast Cells / Q000276:immunology*; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology; D051379:Mice; D018345:Mice, Knockout; D011485:Protein Binding / Q000276:immunology; D019859:Proto-Oncogene Proteins c-met / Q000235:genetics / Q000276:immunology*; D017452:Receptors, IgG / Q000235:genetics / Q000276:immunology; D011991:Receptors, Virus / Q000235:genetics / Q000276:immunology
chemical_list: D001426:Bacterial Proteins; D016207:Cytokines; D016326:Extracellular Matrix Proteins; D039421:Integrin alpha2; D008565:Membrane Proteins; D017452:Receptors, IgG; D011991:Receptors, Virus; C095768:inlB protein, Listeria monocytogenes; D015922:Complement C1q; D019859:Proto-Oncogene Proteins c-met