{'fraction_non_alphanumeric': 0.023693379790940768, 'fraction_numerical': 0.0264808362369338, 'mean_word_length': 5.468468468468468, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Transcriptional Regulation of the Human Peptide Transporter PepT1 by Leptin in Intestinal Epithelia

In the present study we investigated the effect of leptin on hPepT1 expression and activity in Caco2‐BBE cells. We cloned hPepT1 promoter region (−722 to −1) and investigated its promoter activity under leptin stimulation. We found that leptin increases hPepT1 promoter activity that is dose and time dependent. The maximal activity of hPepT1 promoter was at 1 microM leptin for 8 hours. We found that under these conditions, leptin increases by 2 times hPepT1, mRNA, protein expression and transport activity. Deletion analysis of the hPEPT1 promoter suggested that the region spanning −722 to −324 bp was essential the transcriptional activity induced by leptin. This deleted hPepT1 promoter lacked multiple CDX‐2 binding sites. Furthermore we found that leptin induced a greater hPepT1 promoter activity in Caco2‐BBE that over‐expressed CDX2 than in Caco2‐BBE transfected with the vector only. In contrast, using the deleted hPepT1 promoter, leptin failed to induce hPepT1 promoter activity in both Caco2‐BBE over‐expressing CDX2 and Caco2‐BBE cells transfected with the vector only. Interestingly, Leptin induced a greater hPepT1 transport activity in Caco2‐BBE over‐expressing CDX2 than Caco2‐BBE transfected with only the vector. We conclude that CDX2 plays a significant role in the leptin transcriptional regulation of hPepT1.