Evaluation of Serum miR-216a, miR-216b, miR-217, miR-92b, miR-375 and miR-148a as Potential Biomarkers for Acute Pancreatitis and the Role of miR-92b in Attenuating Caerulein-induced Injury and Inflammatory Responses in AR42J Cells

Acute pancreatitis can eventually lead to morbidity and mortality. The present study aimed to identify the differentially expressed microRNAs (miRNAs) that are related to acute pancreatitis and explore the in vitro functional role of miR-92b in acute pancreatitis.Bioinformatics analysis was used to identify differentially expressed miRNAs in caerulein- induced acute pancreatitis samples when compared to normal controls. The role of miR-92b in acute pancreatitis was examined by in vitro functional assays.MiRNA-network analysis revealed 12 miRNAs that function as "core regulatory miRNAs". Further validation studies revealed that six miRNAs (miR-216a, miR-216b, miR-217, miR- 92b, miR-375 and miR-148a) were differentially expressed in the serum samples from patients with acute pancreatitis. These six miRNAs have fair diagnostic potential for severe acute pancreatitis. Caerulein induced cell injury and inflammatory response and repressed miR-92b expression in AR42J cells. MiR-92b overexpression attenuated caerulein-induced cell injury and inflammatory responses in AR42J cells. Luciferase reporter assay showed that mitogen-activated protein kinase 4 (MAP2K4) was a direct target of miR-92b. MiR-92b overexpression repressed MAP2K4 expression, while caerulein up-regulated MAP2K4 expression in AR42J cells. The rescue experiments showed that enforced expression of MAP2K4 partially reversed the miR-92b-mediated protective effects on caerulein-induced AR42J cell injury.In conclusion, we identified miR-216a, miR-216b, miR217, miR-92b, miR-375 and miR-148a as new candidate biomarkers for acute pancreatitis. Further in vitro functional studies revealed that miR-92b attenuated caerulein-induced cell injury and inflammatory responses in AJ42R cells partially via targeting MAP2K4.