Acute pancreatitis (AP), a sudden inflammatory process of pancreas, is painful and may contribute to death. The aberrant expression of miR-27a-5p has been reported in many types of cancers and diseases including AP. Thus, it is urgent to manifest the functions and mechanism of miR-27a-5p in AP. The levels of miR-27a-5p, tumor necrosis factor (TNF) receptor-associated factor 3 (Traf3) in serum of AP patient, or cerulein-treated AR42J cells were detected by qRT-PCR. Functionally, the apoptotic rate, the protein levels of Bcl-2 and Bax, the caspase-3 activity, and the levels of IL-1β, IL-6, and TNF-α in cerulein-treated AR42J cells were measured by flow cytometry, Western blot, caspase-3 activity assay, and qRT-PCR and ELISA assay, respectively. In addition, the putative target of miR-27a-5p was predicted by TargetScan online database, and the dual luciferase reporter assay and RNA immunoprecipitation (RIP) assay were conducted to verify this interaction. Cerulein-treated mouse AP model was established to explore the role of miR-27a-5p in AP in vivo. The level of miR-27a-5p was notably downregulated in AP patients and cerulein-treated AR42J cells. The functional experiments indicated that miR-27a-5p mimics attenuated the promotion effects on cell apoptosis and the inflammatory response in AR42J cells caused by cerulein. The interaction between miR-27a-5p and Traf3 was predicted by TargetScan online database and validated by dual luciferase reporter assay and RIP assay. Following qRT-PCR results exhibited that Traf3 was apparently enhanced in cerulein-treated AR42J cells. The further functional experiments disclosed that Traf3 overexpression relieved the inhibitory effects on cell apoptosis and the inflammatory response induced by miR-27a-5p mimics in cerulein-treated AR42J cells. Moreover, miR-27a-5p alleviated cerulein-induced injury in vivo. In this study, we established the cerulein-treated AR42J cells as AP model in vitro. We validated that miR-27a-5p was significantly downregulated, and Traf3 was strikingly upregulated in AP patient and/or cerulein-treated AR42J cells. The further mechanistical and functional experiments unraveled that miR-27a-5p regulated Traf3 to relieve the cerulein-induced cell apoptosis and inflammatory injury of AR42J cells. Therefore, this novel regulatory network may provide therapeutic target for AP patients.
Keywords: Traf3; acute pancreatitis; cerulein; inflammatory injury; miR-27a-5p.