The importance of butyrate transport to the regulation of gene expression in the colonic epithelium

Abstract

Butyrate is a naturally occurring monocarboxylate, produced in the lumen of the colon by microbial fermentation of complex carbohydrates that escape digestion in the small intestine. It serves as the principal metabolic fuel for colonic epithelial cells, and exerts a variety of effects important to intestinal health and function. This brief discussion focuses on the route, role and regulation of butyrate transport in the large intestine, with particular emphasis on the significance of butyrate transport to the ability of butyrate to modulate expression of genes important to the processes maintaining colonic tissue homoeostasis.

Cellular expression of monocarboxylate transporters (MCT) in the digestive tract of the mouse, rat, and humans, with special reference to slc5a8

“…The SCFA in the bowel lumen have some effects on the intestinal wall, including the stimulation of colonic blood fl ow and of fl uid and electrolyte uptake (30). Butyrate also functions as an energy source of epithelial cells in the large intestine and promotes differentiation of the cells (2,21) while suppressing the proliferation of tumor cells by the induction of apoptosis (6). Thus, direct and indirect intraluminal supplementation of butyrate maintains and strengthens the epithelial integrity to suppress mucosal damage such as ulcerative colitis (15,16,19,27).…”

Enzymatically modified starch up-regulates expression of incretins and sodium-coupled monocarboxylate transporter in jejunum of growing pigs

“…Gut site affected the expression of GLUT2, SMCT, GLP1 and GIP (P < 0.05) and of MCT1 (P = 0.05). 2 and 4 (Cuff and Shirazi-Beechey, 2004;Halestrap et al, 2004;Iwanaga et al, 2006;Sepponen et al, 2007). The intestinal SCFA transporter expression is substrate induced and should therefore respond to changes in luminal SCFA concentrations (Sepponen et al, 2007).…”

Role of USF1 and USF2 as potential repressor proteins for human intestinal monocarboxylate transporter 1 promoter

“…Studies on the regulation of expression of nutrient transporters are of particular importance for those nutrients whose functions are beyond their recognized role in providing energy and in metabolism. In this regard, butyrate, a key SCFA in the colonocytes, is such a nutrient with diversified roles in maintaining colonocyte health, proliferation, and epithelial integrity (6,10). Known cellular effects of butyrate in the colonocytes depend on its intracellular availability, which determines its ability to maintain tissue homeostasis in the colonic epithelium.…”

“…Therefore, there is a precedent for USF playing an important role in the response of cellular genes to various nutrients. Adaptation to nutritional environment by the absorptive cells of the intestinal epithelium is known to be achieved through the modulation of expression of specialized nutrient transporters (10). Although such reports are not available with regard to regulation of MCT1 expression in any tissues, it is not unlikely that USF might play a similar role in the regulation of MCT1, at least in the colonic epithelium, in response to the availability of SCFAs.…”