UNC‐45A is a novel regulator of the intestinal epithelial cell migration

Abstract

Intestinal epithelial cell migration is a fundamental homeostatic process that regulates establishment of the epithelial architecture in healthy gut and drives mucosal wound healing during intestinal inflammation. Epithelial cell migration depends on remodeling of the cytoskeleton, most notably actin filament turnover and activity of nonmuscle myosin II (NM II) motors. The mechanisms that regulate remodeling of the actomyosin cytoskeleton in migrating intestinal epithelial cells remain poorly understood. UNC-45A is a highly conserved member of the UNC45/CRO1/She4p family proteins and it acts as a chaperone facilitating NM II folding and self-assembly. While previous studies implicated this molecular chaperon in controlling motility of fibroblastic and some tumor cells, its roles in regulating intestinal epithelial cell migration remain unexplored. In the present study, CRISPR/Cas9 mediated gene editing was used to downregulate UNC-45A expression in HT29 and SK-CO15 human colonic epithelial cells. Loss of UNC-45A significantly decreased cell contractility in the collagen contraction assay, thereby indicating impaired activity of NM II motors. Importantly, knockout of UNC-45A significantly decreased both collective epithelial cell migration in a wound heling assay and individual cell migration in the Boyden chamber. The attenuated migration of UNC-45A-depleted epithelial cells was accompanied by their increased adhesion to the collagen matrix, disassembly of basal actin stress fibers and inhibited membrane protrusion at the migrating cell edge. Interestingly, UNC-45A expression was significantly downregulated in isolated intestinal epithelial cells and tissue sections obtained from the colonic mucosa of ulcerative colitis patients. Our results signify UNC-45A as a novel cytoskeletal regulator of intestinal epithelial cell migration, which functions could be inhibited in chronic inflammatory disorders.