Fig. 4
From: Vitamin D3 suppresses intestinal epithelial stemness via ER stress induction in intestinal organoids
The effect of vitamin D3 on small intestinal organoids is mediated by endoplasmic reticulum (ER) stress induction. Intestinal organoids were treated with various concentrations (10, 50, and 100 nM) of vitamin D3 and the expression levels of unfolded protein response (UPR) genes, C/EBP homologous protein (CHOP), activating transcription factor 6 (ATF6), total form X-box-binding protein 1 (tXBP1), spliced form (s)XBP1 were quantified using qPCR (a). Small intestinal organoids derived from leucine-rich repeat-containing G-protein-coupled receptor 5-green fluorescent protein (LGR5-GFP) mice were treated with 50 nM vitamin D3 in the presence or absence of the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) (250 or 500 nM). The budding of intestinal organoids was observed under a microscope (left panel), and the percentage of budding organoids was analyzed using the ImageJ software (right panel) (b). The expression level of LGR5 was quantified using qPCR (c), and the numbers of LGR5-GFP-positive cells were visualized using a confocal microscope (green fluorescence) (d). Immunofluorescence images of cleaved caspase-3 (green fluorescence) (e). Data are presented as mean ± standard deviation, *p ≤ 0.05, ***p ≤ 0.0005