Department of Integrated Biomedical Science, Soonchunhyang Institute of Medi-Bio Science, Soonchunhyang University, Cheonan, 31151, Republic of Korea.
Stem Cell Res Ther. 2021 May 13;12(1):285. doi: 10.1186/s13287-021-02361-2.
Vitamin D is important for normal function of the intestinal epithelial cells (IECs). In this study, we aimed to investigate the effects of vitamin D on the differentiation, stemness, and viability of healthy IECs in intestinal organoids.
Intestinal organoids derived from mouse small intestine were treated with vitamin D, and the effects on intestinal stemness and differentiation were evaluated using real-time PCR and immunofluorescence staining of the distinct lineage markers. Cell viability was analyzed using viability and apoptosis assays.
Vitamin D enhanced IEC differentiation into the distinct lineages of specialized IECs, including Paneth, goblet, and enteroendocrine cells and absorptive enterocytes. Decreased expression levels of leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5) and the presence of several LGR5-green fluorescent protein (GFP)-positive cells were observed in vitamin D-treated organoids derived from LGR5-GFP mice. The formation of the crypt-villus structure was also inhibited by vitamin D, suggesting that vitamin D suppresses intestinal cell stemness. Furthermore, the expression levels of unfolded protein response genes, C/EBP homologous protein (CHOP), and activating transcription factor 6 (ATF6) were upregulated in vitamin D-treated organoids. Moreover, vitamin D promoted apoptotic cell death in intestinal cells, which may be associated with the decrease in intestinal stemness. LGR5 gene expression, ISC number, and apoptotic cell death were partially recovered in the presence of the ER stress inhibitor tauroursodeoxycholic acid (TUDCA), suggesting that intestinal stemness suppression and intestinal apoptosis occurred via ER stress activation.
Our study provides important insights into the effects of vitamin D on the induction of IEC differentiation and apoptotic cell death, and inhibition of intestinal stemness accompanied by ER stress augmentation.
维生素 D 对于肠道上皮细胞（IEC）的正常功能非常重要。在这项研究中，我们旨在研究维生素 D 对肠道类器官中健康 IEC 分化、干性和活力的影响。
用维生素 D 处理从小鼠小肠中分离得到的肠道类器官，并通过实时 PCR 和不同谱系标志物的免疫荧光染色评估肠道干性和分化的影响。通过活力和凋亡测定分析细胞活力。
维生素 D 增强了 IEC 向特定 IEC 谱系的分化，包括潘氏细胞、杯状细胞和肠内分泌细胞以及吸收性肠上皮细胞。在用维生素 D 处理的源自 LGR5-GFP 小鼠的类器官中观察到 LGR5 表达水平降低和存在多个 LGR5-绿色荧光蛋白（GFP）阳性细胞。维生素 D 还抑制了隐窝-绒毛结构的形成，表明维生素 D 抑制了肠道细胞干性。此外， unfolded protein response 基因、C/EBP 同源蛋白（CHOP）和激活转录因子 6（ATF6）的表达水平在维生素 D 处理的类器官中上调。此外，维生素 D 促进了肠道细胞的凋亡性细胞死亡，这可能与肠道干性降低有关。在 ER 应激抑制剂牛磺熊脱氧胆酸（TUDCA）存在的情况下，LGR5 基因表达、ISC 数量和凋亡性细胞死亡部分恢复，表明肠道干性抑制和肠道细胞凋亡是通过 ER 应激激活发生的。
我们的研究提供了关于维生素 D 对 IEC 分化和凋亡性细胞死亡诱导以及 ER 应激增强伴随的肠道干性抑制的重要见解。
