miR-9 alleviated the inflammatory response and apoptosis in caerulein-induced acute pancreatitis by regulating FGF10 and the NF-κB signaling pathway.

MicroRNAs (miRs) have been implicated in the development of acute pancreatitis (AP). However, the role and potential mechanism of miR-9 in AP progression remains unclear. Caerulein-treated AR42J cells were used as a cellular model of AP. Results revealed caerulein triggered an inflammatory response by promoting the secretion of inflammatory cytokines [tumor necrosis factor-α, interleukin (IL) 1β and IL-6], as evidenced by ELISA. Furthermore, caerulein-induced apoptosis was reported by flow cytometry and western blot assays. Additionally, miR-9 expression was downregulated by caerulein treatment, as demonstrated by reverse transcription quantitative PCR. However, miR-9 overexpression reduced the inflammatory response and apoptosis in caerulein-treated AR42J cells. miR-9 knockdown resulted in opposite effects. Furthermore, fibroblast growth factor (FGF) 10 was validated to be targeted via miR-9 by luciferase, RNA immunoprecipitation and RNA pull-down assays. Results demonstrated increased FGF10 expression in caerulein-treated AR42J cells and that FGF10 overexpression exacerbated the caerulein-induced inflammatory response and apoptosis, while its knockdown had the opposite effect. Additionally, FGF10 reversed the effect of miR-9 on caerulein-induced injury in AR42J cells. Results demonstrated that miR-9 inhibited the expression of the nuclear factor κB (NF-κB) pathway-related proteins by downregulating FGF10. As a result, miR-9 decreased inflammatory response and apoptosis in caerulein-treated AR42J cells by targeting FGF10 and blocking NF-κB signaling, suggesting that miR-9 may serve as a novel target for AP treatment.