The non-synthetic sweeteners, miraculin and mogroside V, but not stevia, disrupt the intestinal epithelial barrier function through a sweet taste receptor-dependent mechanism.

Impaired intestinal barrier function is a precursor to various metabolic diseases which can occur when the intestinal epithelium is directly exposed to certain dietary components. Previous studies have demonstrated the barrier disruptive effect of artificial sweeteners such as sucralose and saccharin, in the intestinal epithelium. In the present study, we aimed to evaluate the impact of 3 non-synthetic sweeteners, stevia, miraculin, and mogroside V, on Caco-2 monolayer barrier integrity, reactive oxygen species (ROS) production, and tight junction protein expression as compared to the artificial sweetener saccharin. Miraculin and mogroside V exerted a significant impact on cell numbers with decreased cell viability at both 24 and 48 h. ROS production was also significantly increased by miraculin and mogroside V and epithelial barrier function, assessed by transepithelial electrical resistance and FITC-dextran leak, was significantly disrupted with both miraculin and mogroside V. Stevia exhibited no effect on epithelial cell viability, ROS accumulation or barrier function, despite a range of concentrations investigated. Knockdown of the sweet taste receptor, T1R3, significantly attenuated miraculin- and mogroside V-induced loss of cell viability, ROS accumulation and barrier disruption suggesting a T1R3-dependent mechanism. Gene expression analysis revealed differential regulation of cell junction-related genes by mogroside V and miraculin with upregulated expression of genes such as CAV1, CLDN2 and CLDN10, and downregulated expression of genes such as CAV3 and CDH2. These findings demonstrate that miraculin and mogroside V, but not stevia, negatively regulate ROS formation and intestinal epithelial barrier function in a T1R3-dependent manner and potentially through modulation of tight junction proteins. This highlights the need for further investigation into the long-term dietary implications of natural sweeteners, particularly miraculin and mogroside V, on gut health.