Investigation of MCT1 transporter protein in the human gastrointestinal tract (897.1)

Abstract

Bacterially‐derived short chain fatty acids, such as butyrate, are vital in maintaining the symbiotic relationship that exists between humans and their gastrointestinal microbial populations. A key step in this process is the uptake of butyrate into colonic epithelial cells, via MCT1 transporters, which regulates cell differentiation (Cuff et al., 2005). Although previously studied, the exact localisation of MCT1 protein along the human gastrointestinal tract remains controversial (Gill et al., 2006; Iwanaga et al., 2006). The aim of this study was therefore to re‐investigate MCT1 protein abundance in various human gastrointestinal tissues. Initial RT‐PCR analysis confirmed the expected MCT1 RNA expression pattern of colon > small intestine > stomach. Using surgical resection samples, Western analysis utilising the MCT12A antibody (Source Bioscience, UK) detected higher abundance of a 45 kDa MCT1 protein in colon compared to ileum (P<0.05, N = 4, unpaired t‐test). Importantly, MCT1 abundance was found to be significantly higher in ascending and descending colon compared to sigmoid colon (P<0.01, N = 11, ANOVA). In contrast, ileum samples obtained from ileostomy reversal surgeries showed a high MCT1 abundance, with no significant difference between proximal and distal ileum (NS, N = 7, paired t‐test). These data appear to confirm that MCT1 protein abundance is correlated to levels of bacterially‐derived short‐chain fatty acids along the gastrointestinal tract. In addition, they highlight the importance of precise tissue location in studies comparing colonic MCT1 abundance between normal and diseased states.Grant Funding Source: Supported by Science Foundation Ireland and the Kuwaiti government