Transforming Growth Factor-β and Bone Morphogenetic Protein 2 Regulation of MicroRNA-200 Family in Chronic Pancreatitis

Objectives: To investigate regulation of microRNA (miR)-200 family (a, b, c, 141, and 429) in chronic pancreatitis (CP). This was accomplished by examining miR-200 family levels in a mouse model in vivo and their regulation in pancreatic cells in vitro. Methods: Chronic pancreatitis was induced by cerulein for 4 weeks (50 mu g/kg, 5 hourly intraperitoneal injections/day, and 3 days/week). Control mice received normal saline. The pancreata were harvested for fibrosis assessment by Sirius red staining and for miRNA, collagen, and fibronectin levels by quantitative PCR. In vitro, human primary pancreatic stellate cells and human primary pancreatic fibroblast (hPFBs), and rat pancreatic epithelial AR42J cells were treated with vehicle, transforming growth factor (TGF)-beta (1 ng/mL), or BMP2 (50 ng/mL) for 24 hours and then harvested for miRNA analysis. Results: In CP, miR-200s were decreased by 56% to 70% and inversely correlated with pancreatic fibrosis, miR-21, and miR-31 (P < 0.05). In vitro, TGF- inhibited miR-200b in AR42J cells by 62%, whereas BMP2 increased miR-200b in all 3 cell types in a range of 1.5- to 3.4-fold and inhibited miR-21 in hPFBs by 21% (P < 0.05). Conclusions: Both in vivo and in vitro studies suggest an antifibrogenic function of miR-200s in CP. The TGF-beta and BMP2 may function through inverse regulation of miR-200b levels.