Intestinal peptide transporter expression and influence of a peptide diet in colitis rats

本研究利用人肠道Caco-2细胞单层，研究了炎症性肠病中肠肽转运体PEPT1异常表达的机制。PEPT1的表达受肿瘤坏死因子-α和IL-6在mRNA水平上的调节。脂多糖刺激后，PEPT1水平显著降低，提示这可能是由于PEPT1蛋白降解增加或合成减少所致。此外，在氧化应激条件下，PEPT1的mRNA水平降低，并被认为与细胞间黏附的减少有关。研究了饮食对结肠炎大鼠血浆指标的影响，但未观察到多肽饮食对其的影响。

In this study, the mechanism underlying the aberrant expression of the intestinal peptide transporter PEPT1 in inflammatory bowel disease was investigated using the human intestinal Caco-2 cell monolayer. PEPT1 expression was regulated by TNF-alpha and IL-6 at the mRNA level. A significant reduction in the levels of PEPT1 was observed after lipopolysaccharide stimulation, suggesting that this might be attributed to increased degradation or reduced synthesis of the PEPT1 protein. Additionally, PEPT1 mRNA levels decreased under oxidative stress conditions and are thought to be involved in the decrease in cell-cell adhesion. The effects of diet on the plasma index of the colitis rats were studied, but no peptide diet-specific influence was observed.