Intestinal epithelial PKM2 serves as a safeguard against experimental colitis via activating β-catenin signaling.

Abstract

The pyruvate kinase M2 (PKM2)-mediated aerobic glycolysis has been shown to play a critical role in promoting cell survival and proliferation. However, little is known about the function of intestinal epithelial PKM2 in intestine homeostasis. Here we investigate whether and how intestinal epithelial PKM2 modulates the morphology and function of the adult intestine in experimental colitis. Analyzing colonoscopic biopsies from Crohn's disease and ulcerative colitis patients, we found significantly decreased level of intestinal epithelial PKM2 in patients compared to that in non-inflamed tissues. Similar reduction of intestinal epithelial PKM2 was observed in mice with dextran sulfate sodium-induced colitis. Moreover, intestinal epithelial-specific PKM2-knockout (Pkm2-/-) mice displayed more severe intestinal inflammation, as evidenced by a shortened colon, disruption of epithelial tight junctions, an increase in inflammatory cytokine levels, and immune cell infiltration, when compared to wild-type mice. Gene profiling, western blot, and function analyses indicated that cell survival signals, particularly the Wnt/β-catenin pathways, were associated with PKM2 activity. Increasing mouse intestinal epithelial PKM2 expression via delivery of a PKM2-expressing plasmid attenuated experimental colitis. In conclusion, our studies demonstrate that intestinal epithelial PKM2 increases cell survival and wound healing under the colitic condition via activating the Wnt/β-catenin signaling.