MiR-92b-3p ameliorates inflammation and autophagy by targeting TRAF3 and suppressing MKK3-p38 pathway in caerulein-induced AR42J cells.

ABSTRACT

Acute pancreatitis (AP) is an inflammatory disease with high morbidity and mortality. Dysregulation of microRNAs (miRNAs) was involved in human diseases, including AP. However, the effects of miR-92b-3p on AP process and its mechanism remain not been fully clarified. The expression levels of miR-92b-3p and tumor necrosis factor receptor-associated factor-3 (TRAF3) were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The protein levels of TRAF3, tumor necrosis factor α (TNF-α) TNF-α, interleukin-6 (IL-6), phosphorylated mitogen-activated protein kinase kinase 3 (p-MKK3), MKK3, p38 and phosphorylated p38 (p-p38) were detected by western blot. The concentration of TNF-α and IL-6 in the medium was measured using ELISA kits. The possible binding sites of miR-92b-3p and TRAF3 were predicted by TargetScan and verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. The expression level of miR-92b-3p was decreased and TRAF3 expression was increased in AR42J cells stimulated with caerulein. Moreover, the protein levels of pro-inflammatory cytokines (TNF-α and IL-6) were markedly elevated, and the expression levels of autophagy-related markers Beclin1 as well as the ratio of LC3-II/I were obviously increased in AR42J cells treated with caerulein. In addition, overexpression of miR-92b-3p or knockdown of TRAF3 significantly suppressed the release of pro-inflammatory cytokines and autophagy in caerulein-induced AR42J cells. Furthermore, TRAF3 was a direct target of miR-92b-3p and its upregulation reversed the effects of miR-92b-3p overexpression on inflammatory response and autophagy. Besides, overexpression of miR-92b-3p inhibited the activation of the MKK3-p38 pathway by affecting TRAF3 expression. In conclusion, miR-92b-3p attenuated inflammatory response and autophagy by downregulating TRAF3 and suppressing MKK3-p38 pathway in caerulein-induced AR42J cells, providing a novel avenue for treatment of AP.