Effect of T1R3 Taste Receptor Gene Deletion on Dextran Sulfate Sodium-Induced Colitis in Mice

Taste receptor type 1 member 3 (T1R3) recognize umami or sweet tastes and also contributes type 2 immunity and autophagy in small intestine and muscle cells, respectively. Since imbalance of type 1 and type 2 immunity and autophagy affect intestinal bowel disease (IBD), we hypothesized that T1R3 have a potential role in the incidence and progression of colitis. In the present study, we investigated whether genetic deletion of T1R3 impacted aggravation of DSS-induced colitis in mice. We found that T1R3-KO mice showed reduction in colon damage, including reduced inflammation and colon shrinking relative to those of WT mice following DSS treatment. mRNA expression of tight junction components, particularly claudin1 was significantly lower in T1R3-KO mice with trend to lower inflammation related gene mRNA expression in colon. Other parameters, such as response to microbial stimuli in splenic lymphocytes and peritoneal macrophages, gut microbiota composition, and expression of autophagy-related proteins, were similar between WT and KO mice. Together, these results indicated that deletion of T1R3 has a minor role in intestinal inflammation induced by DSS-induced acute colitis in mice.

Sweet Taste Receptor Expression and Its Activation by Sucralose to Regulate Glucose Absorption in Mouse Duodenum

Sucralose (SUC) has been used in the food industry for nearly 30 years since it was first allowed as an artificial sweetener at the end of the 20th century. However, its effects on the body remain not incontrovertible. This work aimed to investigate the influence of SUC exposure on sweetness receptors and glucose absorption and to explore the relationship between them. Mice were exposed with different concentration of SUC (from 0.27 to 0.47 g/L) for 12 weeks. Long-term treatment with SUC resulted in impaired glucose metabolism, manifested in the decrease of glucose tolerance and the increase of sweet taste receptors, glucose transporters, and glucose absorption. This study also provides a method to quantify the glucose absorptivity. In detail, with increasing concentration of SUC, the glucose absorptivities in the dodecadactylon of mice were added 1.48, 1.56, 1.71, and 1.71 times, respectively, showing wide interindividual variation compared with the control group. PRACTICAL APPLICATION: The artificial sweetener, sucralose, has physiological influences of changing glucose metabolism. The small bowel is the main location for glucose metabolism and absorbs the ingested proteins and carbohydrates. And, this study provides a method to quantify the glucose absorptivity of intestine.