RhoA enhances store-operated Ca entry and intestinal epithelial restitution by interacting with TRPC1 after wounding

Chung HK, Rathor N, Wang SR, Wang JY, Rao JN. RhoA enhances store-operated Ca entry and intestinal epithelial restitution by interacting with TRPC1 after wounding. Am J Physiol Gastrointest Liver Physiol 309: G759–G767, 2015. First published September 3, 2015; doi:10.1152/ajpgi.00185.2015.—Early mucosal restitution occurs as a consequence of epithelial cell migration to resealing of superficial wounds after injury. Our previous studies show that canonical transient receptor potential-1 (TRPC1) functions as a store-operated Ca channel (SOC) in intestinal epithelial cells (IECs) and plays an important role in early epithelial restitution by increasing Ca influx. Here we further reported that RhoA, a small GTP-binding protein, interacts with and regulates TRPC1, thus enhancing SOC-mediated Ca entry (SOCE) and epithelial restitution after wounding. RhoA physically associated with TRPC1 and formed the RhoA/TRPC1 complexes, and this interaction increased in stable TRPC1-transfected IEC-6 cells (IEC-TRPC1). Inactivation of RhoA by treating IEC-TRPC1 cells with exoenzyme C3 transferase (C3) or ectopic expression of dominant negative RhoA (DNMRhoA) reduced RhoA/TRPC1 complexes and inhibited Ca influx after store depletion, which was paralleled by an inhibition of cell migration over the wounded area. In contrast, ectopic expression of wild-type (WT)RhoA increased the levels of RhoA/TRPC1 complexes, induced Ca influx through activation of SOCE, and promoted cell migration after wounding. TRPC1 silencing by transfecting stable WT RhoA-transfected cells with siRNA targeting TRPC1 (siTRPC1) reduced SOCE and repressed epithelial restitution. Moreover, ectopic overexpression of WT-RhoA in polyamine-deficient cells rescued the inhibition of Ca influx and cell migration induced by polyamine depletion. These findings indicate that RhoA interacts with and activates TRPC1 and thus stimulates rapid epithelial restitution after injury by inducing Ca signaling.