RESUMO
Acute lung injury (ALI) and the subsequent acute respiratory distress syndrome remain devastating diseases with high mortality rates and poor prognoses among patients in intensive care units. The present study is aimed at investigating the role and underlying mechanisms of microRNA-31-5p (miR-31-5p) on lipopolysaccharide- (LPS-) induced ALI. Mice were pretreated with miR-31-5p agomir, antagomir, and their negative controls at indicated doses for 3 consecutive days, and then they received a single intratracheal injection of LPS (5 mg/kg) for 12 h to induce ALI. MH-S murine alveolar macrophage cell lines were cultured to further verify the role of miR-31-5p in vitro. For AMP-activated protein kinase α (AMPKα) and calcium-binding protein 39 (Cab39) inhibition, compound C or lentiviral vectors were used in vivo and in vitro. We observed an upregulation of miR-31-5p in lung tissue upon LPS injection. miR-31-5p antagomir alleviated, while miR-31-5p agomir exacerbated LPS-induced inflammation, oxidative damage, and pulmonary dysfunction in vivo and in vitro. Mechanistically, miR-31-5p antagomir activated AMPKα to exert the protective effects that were abrogated by AMPKα inhibition. Further studies revealed that Cab39 was required for AMPKα activation and pulmonary protection by miR-31-5p antagomir. We provide the evidence that endogenous miR-31-5p is a key pathogenic factor for inflammation and oxidative damage during LPS-induced ALI, which is related to Cab39-dependent inhibition of AMPKα.
Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Lesão Pulmonar Aguda/patologia , Proteínas de Ligação ao Cálcio/metabolismo , MicroRNAs/metabolismo , Proteínas Quinases Ativadas por AMP/genética , Lesão Pulmonar Aguda/tratamento farmacológico , Animais , Antagomirs/metabolismo , Antagomirs/uso terapêutico , Gasometria , Proteínas de Ligação ao Cálcio/antagonistas & inibidores , Proteínas de Ligação ao Cálcio/genética , Modelos Animais de Doenças , Interleucina-6/genética , Interleucina-6/metabolismo , Lipopolissacarídeos/toxicidade , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/antagonistas & inibidores , MicroRNAs/genética , Estresse Oxidativo/efeitos dos fármacos , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Transdução de Sinais/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Regulação para Cima/efeitos dos fármacosRESUMO
Acute lung injury (ALI) is the common and complicated inflammatory lung disease. MicroRNAs (miRNA) have emerged as novel gene regulatory molecules which play a crucial role in multiple complicated diseases, including ALI. In this study, we aims to identify potential regulatory functions of miRNA-1246 in lipopolysaccharide (LPS)-induced ALI. In ALI mice, miRNA-1246 expression is effectively up-regulated, compared with the control group. miRNA-1246 overexpression effectively increases inflammation and apoptosis of in vitro ALI model. In contrast, miRNA-1246 knockdown effectively inhibits inflammation and cell apoptosis in vitro ALI model. Furthermore, up-regulation of miRNA-1246 significantly induces nuclear factor-kappa B (NF-κB) protein expression, and suppresses Wnt and ß-catenin protein expression in vitro ALI model. Following the inhibition of NF-κB or Wnt/ß-catenin signal using inhibitors, miRNA-1246 shows no significant effects on ALI-induced inflammation and apoptosis. Taken together, miRNA-1246 mediates ALI-induced lung inflammation and apoptosis via the NF-κB activation and Wnt/ß-catenin suppression.
