RESUMO
ChemR23 is a chemotactic receptor expressed by APCs, such as dendritic cells, macrophages, and NK cells. Chemerin, the ChemR23 ligand, was detected by immunohistochemistry, to be associated with inflamed endothelial cells in autoimmune diseases, such as lupus erythematosus, psoriasis, and rheumatoid arthritis. This study reports that blood and lymphatic murine endothelial cells produce chemerin following retinoic acid stimulation. Conversely, proinflammatory cytokines, such as TNF-α, IFN-γ, and LPS, or calcitriol, are not effective. Retinoic acid-stimulated endothelial cells promoted dendritic cell adhesion under shear stress conditions and transmigration in a ChemR23-dependent manner. Activated endothelial cells upregulated the expression of the atypical chemotactic receptor CCRL2/ACKR5, a nonsignaling receptor able to bind and present chemerin to ChemR23(+) dendritic cells. Accordingly, activated endothelial cells expressed chemerin on the plasma membrane and promoted in a more efficient manner chemerin-dependent transmigration of dendritic cells. Finally, chemerin stimulation of myeloid dendritic cells induced the high-affinity binding of VCAM-1/CD106 Fc chimeric protein and promoted VCAM-1-dependent arrest to immobilized ligands under shear stress conditions. In conclusion, this study reports that retinoic acid-activated endothelial cells can promote myeloid and plasmacytoid dendritic cell transmigration across endothelial cell monolayers through the endogenous production of chemerin, the upregulation of CCRL2, and the activation of dendritic cell ß1 integrin affinity.
Assuntos
Fatores Quimiotáticos/imunologia , Células Dendríticas/imunologia , Células Endoteliais/imunologia , Peptídeos e Proteínas de Sinalização Intercelular/imunologia , Migração Transendotelial e Transepitelial/imunologia , Animais , Antineoplásicos/farmacologia , Adesão Celular/efeitos dos fármacos , Adesão Celular/genética , Adesão Celular/imunologia , Linhagem Celular , Quimiocinas , Fatores Quimiotáticos/genética , Células Dendríticas/citologia , Células Endoteliais/citologia , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/imunologia , Peptídeos e Proteínas de Sinalização Intercelular/genética , Camundongos , Camundongos Knockout , Receptores CCR , Receptores de Quimiocinas/genética , Receptores de Quimiocinas/imunologia , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/imunologia , Migração Transendotelial e Transepitelial/efeitos dos fármacos , Migração Transendotelial e Transepitelial/genética , Tretinoína/farmacologia , Molécula 1 de Adesão de Célula Vascular/genética , Molécula 1 de Adesão de Célula Vascular/imunologiaRESUMO
Chemokine CC motif receptor-like 2 (CCRL2) is a heptahelic transmembrane receptor that shows the highest degree of homology with CCR1, an inflammatory chemokine receptor. CCRL2 mRNA was rapidly (30 minutes) and transiently (2-4 hours) regulated during dendritic cell (DC) maturation. Protein expression paralleled RNA regulation. In vivo, CCRL2 was expressed by activated DC and macrophages, but not by eosinophils and T cells. CCRL2(-/-) mice showed normal recruitment of circulating DC into the lung, but a defective trafficking of antigen-loaded lung DC to mediastinal lymph nodes. This defect was associated to a reduction in lymph node cellularity and reduced priming of T helper cell 2 response. CCRL2(-/-) mice were protected in a model of ovalbumin-induced airway inflammation, with reduced leukocyte recruitment in the BAL (eosinophils and mononuclear cells) and reduced production of the T helper cell 2 cytokines, interleukin-4 and -5, and chemokines CCL11 and CCL17. The central role of CCRL2 deficiency in DC was supported by the fact that adoptive transfer of CCRL2(-/-) antigen-loaded DC in wild-type animals recapitulated the phenotype observed in knockout mice. These data show a nonredundant role of CCRL2 in lung DC trafficking and propose a role for this receptor in the control of excessive airway inflammatory responses.
Assuntos
Movimento Celular , Células Dendríticas/citologia , Células Dendríticas/imunologia , Pulmão/citologia , Receptores de Quimiocinas/imunologia , Alérgenos/imunologia , Animais , Citocinas/imunologia , Células Dendríticas/metabolismo , Deleção de Genes , Regulação da Expressão Gênica , Inflamação/induzido quimicamente , Linfonodos/citologia , Linfócitos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Receptores CCR , Receptores de Quimiocinas/genéticaRESUMO
Psoriasis is a type I interferon-driven T cell-mediated disease characterized by the recruitment of plasmacytoid dendritic cells (pDC) into the skin. The molecules involved in pDC accumulation in psoriasis lesions are unknown. Chemerin is the only inflammatory chemotactic factor that is directly active on human blood pDC in vitro. The aim of this study was to evaluate the role of the chemerin/ChemR23 axis in the recruitment of pDC in psoriasis skin. Prepsoriatic skin adjacent to active lesions and early lesions were characterized by a strong expression of chemerin in the dermis and by the presence of CD15(+) neutrophils and CD123(+)/BDCA-2(+)/ChemR23(+) pDC. Conversely, skin from chronic plaques showed low chemerin expression, segregation of neutrophils to epidermal microabscesses, and few pDC in the dermis. Chemerin expression was localized mainly in fibroblasts, mast cells, and endothelial cells. Fibroblasts cultured from skin of psoriatic lesions expressed higher levels of chemerin messenger RNA and protein than fibroblasts from uninvolved psoriatic skin or healthy donors and promoted pDC migration in vitro in a chemerin-dependent manner. Therefore, chemerin expression specifically marks the early phases of evolving skin psoriatic lesions and is temporally strictly associated with pDC. These results support a role for the chemerin/ChemR23 axis in the early phases of psoriasis development.