Cyclosporine regulates intestinal epithelial apoptosis via TGF-beta-related signaling

Satoh Y, Ishiguro Y, Sakuraba H, Kawaguchi S, Hiraga H, Fukuda S, Nakane A. Cyclosporine regulates intestinal epithelial apoptosis via TGF-beta-related signaling. Am J Physiol Gastrointest Liver Physiol 297: G514-G519, 2009. First published July 16, 2009; doi: 10.1152/ajpgi.90608.2008.-Cyclosporine is a potent immunomodulator and has a beneficial effect in the treatment of ulcerative colitis (UC). We analyzed the mechanism of the effects of cyclosporine on the regulation of epithelial apoptosis via TGF-beta-related signaling, because the balance between the apoptosis and regeneration of epithelial cells seems to be a key factor to maintain the intestinal homeostasis. For this purpose, colitis was induced by treatment of 4% dextran sulfate sodium (DSS), and the effect of treatment with cyclosporine and anti-TGF-beta antibody was assessed. Treatment with cyclosporine ameliorated body weight loss, mucosal destruction, and epithelial apoptosis in DSS-induced colitis. Cyclosporine was shown to upregulate the expression of TGF-beta in the colonic tissue, enhance the expression of p-Smad2 and cFLIP in epithelial cells, and inhibit caspase-8 activity but not caspase-1 or -9. Upregulation of cFLIP in the colonic epithelial cells, amelioration of body weight loss, and mucosal destruction by cyclosporine were attenuated by anti-TGF-beta antibody treatment. These results indicated that cyclosporine could have a protective role against epithelial apoptosis associated with upregulation of TGF-beta-related signaling.