RESUMO
CC chemokines play an important role in the pathogenesis of idiopathic pulmonary fibrosis. Few studies have evaluated the efficacy of therapeutically targeting CC chemokines and their receptors during interstitial lung diseases. In the present study, the therapeutic effects of Evasin-1, a tick-derived chemokine-binding protein that has high affinity for CCL3/microphage inflammatory protein (MIP)-1α, was investigated in a murine model of bleomycin-induced lung fibrosis. CCL3/MIP-1α concentrations in lung homogenates increased significantly with time after bleomycin challenge, and this was accompanied by increased number of leukocytes and elevated levels of CCL2/monocyte chemoattractant protein (MCP)-1, CCL5/regulated upon activation, normal T cell expressed and secreted, TNF-α and transforming growth factor-ß(1), and pulmonary fibrosis. Administration of evasin-1 on a preventive (from the day of bleomycin administration) or therapeutic (from Day 8 after bleomycin) schedule decreased number of leukocytes in the lung, reduced levels of TNF-α and transforming growth factor-ß(1), and attenuated lung fibrosis. These protective effects were similar to those observed in CCL3/MIP-1α-deficient mice. In conclusion, targeting CCL3/MIP-1α by treatment with evasin-1 is beneficial in the context of bleomycin-induced lung injury, even when treatment is started after the fibrogenic insult. Mechanistically, evasin-1 treatment was associated with decreased recruitment of leukocytes and production of fibrogenic cytokines. Modulation of CCL3/MIP-1α function by evasin-1 could be useful for the treatment of idiopathic pulmonary fibrosis.
Assuntos
Antibióticos Antineoplásicos/efeitos adversos , Bleomicina/efeitos adversos , Quimiocina CCL3/antagonistas & inibidores , Quimiocina CCL3/imunologia , Fibrose Pulmonar/tratamento farmacológico , Receptores de Quimiocinas/uso terapêutico , Animais , Antibióticos Antineoplásicos/administração & dosagem , Bleomicina/farmacologia , Quimiocina CCL3/genética , Quimiocina CCL3/metabolismo , Modelos Animais de Doenças , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/imunologia , Leucócitos/imunologia , Leucócitos/metabolismo , Leucócitos/patologia , Masculino , Camundongos , Camundongos Knockout , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/imunologia , Fibrose Pulmonar/metabolismo , Fibrose Pulmonar/patologia , Receptores de Quimiocinas/química , Rhipicephalus sanguineus/química , Fator de Crescimento Transformador beta/biossíntese , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/imunologia , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologiaRESUMO
Chemokine receptors are G protein-coupled receptors that mediate migration and activation of leukocytes as an important part of a protective immune response to injury and infection. In addition, chemokine receptors are used by HIV-1 to infect CD4 positive cells. The structural bases of chemokine receptor recognition and signal transduction are currently being investigated. High-resolution X-ray diffraction and NMR spectroscopy of chemokines indicate that all these peptides exhibit a common folding pattern, in spite of its low degree of primary-sequence homology. Chemokines' functional motifs have been identified by mutagenesis studies, and a possible mechanism for receptor recognition and activation is proposed, but high-resolution structure data of chemokine receptors is not yet available. Studies with receptor chimeras have identified the putative extracellular domains as the major selectivity determinants. Single-amino acid substitutions in the extracellular domains produce profound changes in receptor specificity, suggesting that motifs in these domains operate as a restrictive barrier to a common activation motif. Similarly HIV-1 usage of chemokine receptors involve interaction of one or more extracellular domains of the receptor with conserved and variable domains on the viral envelope protein gp 120, indicating a highly complex interaction. Elucidating the structural requirements for receptor interaction with chemokines and with HIV-1 will provide important insights into understanding the mechanisms of chemokine recognition and receptor activation. In addition, this information can greatly facilitate the design of effective immunomodulatory and anti-HIV-1 therapeutic agents.
Assuntos
Linfócitos T CD4-Positivos/virologia , HIV/metabolismo , Receptores de Quimiocinas/química , Humanos , Conformação Proteica , Receptores de Quimiocinas/metabolismo , Receptores de Quimiocinas/fisiologia , Receptores de HIV/metabolismo , Relação Estrutura-AtividadeRESUMO
Chemokine receptors are G protein-coupled receptors that mediate migration and activation of leukocytes as an important part of a protective immune response to injury and infection. In addition, chemokine receptors are used by HIV-1 to infect CD4 positive cells. The structural bases of chemokine receptor recognition and signal transduction are currently being investigated. High-resolution X-ray diffraction and NMR spectroscopy of chemokines indicate that all these peptides exhibit a common folding pattern, in spite of its low degree of primary-sequence homology. Chemokines' functional motifs have been identified by mutagenesis studies, and a possible mechanism for receptor recognition and activation is proposed, but high-resolution structure data of chemokine receptors is not yet available. Studies with receptor chimeras have identified the putative extracellular domains as the major selectivity determinants. Single-amino acid substitutions in the extracellular domains produce profound changes in receptor specificity, suggesting that motifs in these domains operate as a restrictive barrier to a common activation motif. Similarly HIV-1 usage of chemokine receptors involves interaction of one or more extracellular domains of the receptor with conserved and variable domains on the viral envelope protein gp 120, indicating a highly complex interaction. Elucidating the structural requirements for receptor interaction with chemokines and with HIV-1 will provide important insights into understanding the mechanisms of chemokine recognition and receptor activation. In addition, this information can greatly facilitate the design of effective inmunomodulatory and anti-HIV-1 therapeutic agents