RESUMO
Galectin-8 belongs to a family of mammalian lectins that recognize glycoconjugates present on different cell surface components and modulate a variety of cellular processes. A role of Gal-8 in the immune system has been proposed based on its effects in immune cells, including T and B lymphocytes, as well as the presence of anti-Gal-8 autoantibodies in the prototypic autoimmune disease systemic lupus erythematosus (SLE). We have previously described that Gal-8 induces apoptosis in activated T cells interacting with certain β1 integrins and this effect is counteracted by the anti-Gal-8 autoantibodies. Given that Gal-8 can potentially interact with several glycoproteins, here we analyzed the β2 integrin Lymphocyte Function-Associated Antigen-1 (LFA-1), which is involved in leukocyte cell adhesion and immunological synapses. We show by GST-pull down assays that Gal-8 interacts with LFA-1 and this interaction is inhibited by anti-Gal-8 autoantibodies isolated from SLE patients. In cell adhesion assays, Gal-8 precluded the interaction of LFA-1 with its ligand Intracellular Adhesion Molecule-1 (ICAM-1). These results suggest that Gal-8 can exert immunosuppressive action not only by inducing apoptosis in activated T cells but also by negatively modulating the crucial function of LFA-1 in the immune system, while function-blocking autoantibodies counteract these effects.
Assuntos
Humanos , Galectinas/metabolismo , Molécula 1 de Adesão Intercelular/metabolismo , Lúpus Eritematoso Sistêmico/imunologia , Antígeno-1 Associado à Função Linfocitária/metabolismo , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/metabolismo , Autoanticorpos/imunologia , Autoanticorpos/metabolismo , Adesão CelularRESUMO
PURPOSE: To compare gene expression of the chemokines RANTES and eotaxin-2, its receptor, CCR-3, adhesion molecule ICAM-1 and its receptor LFA-1 in eosinophilic polyps and in control normal nasal mucosa. METHODS: Gene expression was quantified by Real Time PCR in polyps (n=35) and in healthy nasal mucosa (n=15). RESULTS: Eosinophilic polyps showed a higher expression of eotaxin-2 and RANTES, but not of CCR-3, ICAM-1 or LFA-1 compared to control nasal mucosa. CONCLUSION: Eosinophilic polyps present greater expression of eotaxin-2 and RANTES, but not of CCR-3, ICAM-1 or LFA-1 compared to control nasal mucosa.
OBJETIVO: Comparar a expressão gênica das quimiocinas RANTES e eotaxina-2, do seu receptor CCR-3, da molécula de adesão ICAM-1 e do seu receptor LFA-1 entre pólipos nasais eosinofílicos (PE) (n=35) e mucosa nasal controle (n=15). MÉTODOS: Quantificou-se a expressão gênica dos mediadores citados pela técnica de PCR em tempo real em PEs e em mucosas de concha média de pacientes sem doenças nasais ou alteração endoscópica. RESULTADOS: Pólipos eosinofílicos apresentam maior expressão de eotaxina-2 e RANTES, mas não de CCR-3, ICAM-1 e LFA-1, quando comparados as mucosas nasais controles. CONCLUSÃO: Pólipos eosinofícios apresentaram maior expressão de eotaxin-2 and RANTES, mas não de CCR-3, ICAM-1 ou LFA-1,comparada à mucosa nasal controle.
Assuntos
Humanos , Pólipos Nasais/metabolismo , Rinite/metabolismo , Sinusite/metabolismo , Estudos de Casos e Controles , Doença Crônica , /genética , /metabolismo , /genética , /metabolismo , Expressão Gênica , Molécula 1 de Adesão Intercelular/genética , Molécula 1 de Adesão Intercelular/metabolismo , Antígeno-1 Associado à Função Linfocitária/genética , Antígeno-1 Associado à Função Linfocitária/metabolismo , Mucosa Nasal , Pólipos Nasais/complicações , Reação em Cadeia da Polimerase , /genética , /metabolismo , Rinite/complicações , Sinusite/complicaçõesRESUMO
The basic route and mechanism for diapedesis has not yet to be fully defined. Here we present evidence that "cell-cell separation" between endothelial cells (ECs) may provide a route for leukocyte diapedesis. We unexpectedly found that extensive interaction between peripheral blood leukocytes and ECs that were activated by TNF-alpha induced the opening of EC contacts and, surprisingly, resulted in cell-cell separation. This event was specific to the intercellular adhesion molecules-1 (ICAM-1)/leukocyte function-associated antigen-1 interaction, as demonstrated by the following: (1) ICAM-1 expression correlated with increased EC contraction; and (2) the blocking of ICAM-1 selectively inhibited EC separation. Thus, we suggest that "cell-cell separation" could be a mechanism for diapedesis in situations that may require massive leukocyte infiltration.
Assuntos
Humanos , Movimento Celular , Células Cultivadas , Células Endoteliais/citologia , Citometria de Fluxo , Imunofluorescência , Molécula 1 de Adesão Intercelular/metabolismo , Leucócitos/citologia , Antígeno-1 Associado à Função Linfocitária/metabolismoRESUMO
The basic route and mechanism for diapedesis has not yet to be fully defined. Here we present evidence that "cell-cell separation" between endothelial cells (ECs) may provide a route for leukocyte diapedesis. We unexpectedly found that extensive interaction between peripheral blood leukocytes and ECs that were activated by TNF-alpha induced the opening of EC contacts and, surprisingly, resulted in cell-cell separation. This event was specific to the intercellular adhesion molecules-1 (ICAM-1)/leukocyte function-associated antigen-1 interaction, as demonstrated by the following: (1) ICAM-1 expression correlated with increased EC contraction; and (2) the blocking of ICAM-1 selectively inhibited EC separation. Thus, we suggest that "cell-cell separation" could be a mechanism for diapedesis in situations that may require massive leukocyte infiltration.