miR-551b-5p increases intracellular Ca 2+ concentration but does not alter c-Kit expression in rat interstitial cells of Cajal

To investigate the effect of the severe acute pancreatitis (SAP)-related miR-551b-5p on intracellular Ca concentration and c-Kit expression and distribution in rat interstitial cells of Cajal (ICCs) . ICCs were isolated from 5-10-day-old rats and cultured . The cultured ICCs were divided into five groups: a normal control group; a group transfected with an miR-551b-5p mimic; a group transfected with an miR-551b-5p inhibitor; a group transfected with a negative control for the miR-551b-5p mimic; and a group transfected with a negative control for the miR-551b-5p inhibitor. After transfection, real-time PCR was used to detect miR-551b-5p and c-Kit expression. A Western blot analysis was used to determine the expression of c-Kit protein. Confocal microscopy combined with immunofluorescence and Fluo 3-acetoxymethyl (AM) fluorescence were used to determine the localization of c-Kit and intracellular Ca concentration, respectively. Transfection with the miR-551b-5p mimic or inhibitor resulted in overexpression or downregulation of miR-551b-5p in ICCs, respectively. The overexpression or downregulation of miR-551b-5p had no significant influence on c-Kit mRNA or protein levels. The overexpression of miR-551b-5p significantly increased the intracellular Ca concentration, and the downregulation of miR-551b-5p significantly decreased the intracellular Ca concentration. miR-551b-5p increases intracellular Ca concentration but does not alter c-Kit expression in rat ICCs, suggesting that it functions in ICCs by regulating the intracellular Ca concentration downstream or independently of c-Kit signaling.