Saito Yuki, Iwatsuki Ken, Hanyu Hikaru, Maruyama Natsuki, Aihara Eitaro, Tadaishi Miki, Shimizu Makoto, Kobayashi-Hattori Kazuo
Department of Nutritional Science, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.
Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.
Biochem Biophys Res Commun. 2017 Jun 17;488(1):171-176. doi: 10.1016/j.bbrc.2017.05.029. Epub 2017 May 5.
We investigated the effects of essential amino acids on intestinal stem cell proliferation and differentiation using murine small intestinal organoids (enteroids) from the jejunum. By selectively removing individual essential amino acids from culture medium, we found that 24 h of methionine (Met) deprivation markedly suppressed cell proliferation in enteroids. This effect was rescued when enteroids cultured in Met deprivation media for 12 h were transferred to complete medium, suggesting that Met plays an important role in enteroid cell proliferation. In addition, mRNA levels of the stem cell marker leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) decreased in enteroids grown in Met deprivation conditions. Consistent with this observation, Met deprivation also attenuated Lgr5-EGFP fluorescence intensity in enteroids. In contrast, Met deprivation enhanced mRNA levels of the enteroendocrine cell marker chromogranin A (ChgA) and markers of K cells, enterochromaffin cells, goblet cells, and Paneth cells. Immunofluorescence experiments demonstrated that Met deprivation led to an increase in the number of ChgA-positive cells. These results suggest that Met deprivation suppresses stem cell proliferation, thereby promoting differentiation. In conclusion, Met is an important nutrient in the maintenance of intestinal stem cells and Met deprivation potentially affects cell differentiation.
我们使用来自空肠的小鼠小肠类器官（肠小体）研究了必需氨基酸对肠道干细胞增殖和分化的影响。通过从培养基中选择性去除单个必需氨基酸，我们发现蛋氨酸（Met）缺乏24小时会显著抑制肠小体细胞增殖。当在蛋氨酸缺乏培养基中培养12小时的肠小体转移到完全培养基中时，这种效应得到挽救，这表明蛋氨酸在肠小体细胞增殖中起重要作用。此外，在蛋氨酸缺乏条件下生长的肠小体中，干细胞标志物富含亮氨酸重复序列的G蛋白偶联受体5（Lgr5）的mRNA水平降低。与这一观察结果一致，蛋氨酸缺乏也减弱了肠小体中Lgr5-EGFP的荧光强度。相反，蛋氨酸缺乏增强了肠内分泌细胞标志物嗜铬粒蛋白A（ChgA）以及K细胞、肠嗜铬细胞、杯状细胞和潘氏细胞标志物的mRNA水平。免疫荧光实验表明，蛋氨酸缺乏导致ChgA阳性细胞数量增加。这些结果表明，蛋氨酸缺乏会抑制干细胞增殖，从而促进分化。总之，蛋氨酸是维持肠道干细胞的重要营养素，蛋氨酸缺乏可能会影响细胞分化。
