miR-148a and miR-551b-5p regulate inflammatory responses via regulating autophagy in acute pancreatitis.

Acute pancreatitis (AP) is a common inflammatory response that occurs in the pancreas with mortality rates as high as 30 %. However, there is still no consistent and effective treatment for AP now. MicroRNA-148 was reported to be involved in AP through IL-6 signaling pathway. Therefore, we aimed to further explore the detailed mechanisms of AP, to develop more therapeutic approach for AP. Exosomes were isolated from peripheral blood mononuclear cells of 20 AP patients and 20 healthy volunteers to evaluate the abnormally expressed miRNA. Then pancreatic acinar cells (PACs) were transfected with retrovirus to overexpress miR-148a/miR-551b-5p to evaluate their function. Both miR-148a and miR-551b-5p were highly expressed in AP patients than these in healthy cases. Then overexpressing miR-551b-5p in PACs could regulate autophagy through directly binding to Baculoviral IAP Repeat Containing 6, leading to the increased secretions of interleukin-1β (IL-1β) and interleukin-18 (IL-18) through interleukin-1 (IL-1) signaling pathway. Moreover, overexpressing miR-148a in PACs could decrease the secretions of IL-1β and IL-18 to modulate autophagy. The exosomal miRNA-148a and miRNA-551b-5p derived from peripheral blood mononuclear cells of AP patients may two-way mediate autophagy damage through IL-6/STAT3 signaling pathway, which participated in the AP pathogenesis. Our findings may provide new targets for the diagnosis and treatment of AP.