Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Center for Intestinal and Liver Inflammation Research, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois.
Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.
Am J Physiol Cell Physiol. 2020 Apr 1;318(4):C732-C739. doi: 10.1152/ajpcell.00335.2019. Epub 2020 Feb 12.
Sirtuin 6 (Sirt6) is predominantly expressed in epithelial cells in intestinal crypts. It plays an important role in protecting intestinal epithelial cells against inflammatory injury. Previously, we found that colitis is associated with the downregulation of Sirt6 protein in the intestines. Here, we report that murine interferon-γ (Ifnγ) inhibits Sirt6 protein but not mRNA expression in young adult mouse colonocytes (YAMC, a mouse colonic epithelial cell line) in a dose- and time-dependent manner. Using microRNA array analysis, we showed that Ifnγ induces expression of in YAMC cells. With in silico analysis, we found that the 3'-untranslated region (UTR) contains a putative binding site for . Luciferase assay showed that Ifnγ inhibited 3'-UTR activity and this effect was mimicked by via directly targeting the seed site in the 3'-UTR of mRNA. Furthermore, Western blot demonstrated that downregulated Sirt6 protein expression in YAMC cells. Blocking with a specific inhibitor attenuated the inhibitory effect of Ifnγ on Sirt6 protein expression in the cells. Collectively, our data suggest that Ifnγ inhibits Sirt6 protein expression in intestinal epithelial cells via a -mediated mechanism. may be a novel therapeutic target for rescuing Sirt6 protein levels in intestinal epithelial cells, thereby protecting against intestinal mucosal injury caused by inflammation.
Sirtuin 6（Sirt6）主要在肠道隐窝的上皮细胞中表达。它在保护肠道上皮细胞免受炎症损伤方面发挥着重要作用。先前，我们发现结肠炎与肠道中 Sirt6 蛋白的下调有关。在这里，我们报告干扰素-γ（Ifnγ）在年轻成年鼠结肠细胞（YAMC，一种鼠结肠上皮细胞系）中以剂量和时间依赖的方式抑制 Sirt6 蛋白而不是 mRNA 的表达。通过 microRNA 阵列分析，我们表明 Ifnγ诱导 YAMC 细胞中 的表达。通过计算机分析，我们发现 3'-非翻译区（UTR）包含一个假定的结合位点。荧光素酶报告基因实验表明，Ifnγ抑制 3'-UTR 活性，并且 通过直接靶向 mRNA 3'-UTR 中的 种子位点模拟这种效应。此外，Western blot 表明 下调 YAMC 细胞中的 Sirt6 蛋白表达。用特异性抑制剂阻断 可减弱 Ifnγ对细胞中 Sirt6 蛋白表达的抑制作用。总之，我们的数据表明 Ifnγ 通过 -介导的机制抑制肠道上皮细胞中的 Sirt6 蛋白表达。 可能是一种恢复肠道上皮细胞中 Sirt6 蛋白水平的新型治疗靶点，从而防止炎症引起的肠道黏膜损伤。
