环鸟苷酸-腺苷酸合酶通过 Beclin-1 介导的自噬促进肠道炎症中的上皮细胞稳态。
Cyclic GMP-AMP synthase contributes to epithelial homeostasis in intestinal inflammation via Beclin-1-mediated autophagy.
机构信息
Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
Division of Pediatric Surgery, UPMC Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
出版信息
FASEB J. 2022 May;36(5):e22282. doi: 10.1096/fj.202200138R.
Inflammatory bowel disease (IBD) represents a set of idiopathic and chronic inflammatory diseases of the gastrointestinal tract. Central to the pathogenesis of IBD is a dysregulation of normal intestinal epithelial homeostasis. cGAS is a DNA-sensing receptor demonstrated to promote autophagy, a mechanism that removes dysfunctional cellular components. Beclin-1 is a crucial protein involved in the initiation of autophagy. We hypothesized that cGAS plays a key role in intestinal homeostasis by upregulating Beclin-1-mediated autophagy. We evaluated intestinal cGAS levels in humans with IBD and in murine colonic tissue after performing a 2% dextran sulfate sodium (DSS) colitis model. Autophagy and cell death mechanisms were studied in cGAS KO and WT mice via qPCR, WB analysis, H&E, IF, and TUNEL staining. Autophagy was measured in stimulated intestinal epithelial cells (IECs) via WB analysis. Our data demonstrates cGAS to be upregulated during human and murine colitis. Furthermore, cGAS deficiency leads to worsened colitis and decreased levels of autophagy proteins including Beclin-1 and LC3-II. Co-IP demonstrates a direct binding between cGAS and Beclin-1 in IECs. Transfection of cGAS in stimulated HCT-116 cells leads to increased autophagy. IECs isolated from cGAS KO have diminished autophagic flux. cGAS KO mice subjected to DSS have increased cell death and cleaved caspase-3. Lastly, treatment of cGAS KO mice with rapamycin decreased the severity of colitis. Our data suggest that cGAS maintains intestinal epithelial homeostasis during human IBD and murine colitis by upregulating Beclin-1-mediated autophagy and preventing IEC death. Rescue of autophagy can attenuate the severity of colitis associated with cGAS deficiency.
炎症性肠病(IBD)代表了一组特发性和慢性胃肠道炎症性疾病。IBD 的发病机制核心是正常肠道上皮细胞稳态的失调。cGAS 是一种已被证明可促进自噬的 DNA 感应受体,该机制可清除功能失调的细胞成分。Beclin-1 是参与自噬起始的关键蛋白。我们假设 cGAS 通过上调 Beclin-1 介导的自噬在肠道稳态中发挥关键作用。我们评估了患有 IBD 的人类和在进行 2%葡聚糖硫酸钠(DSS)结肠炎模型后鼠结肠组织中的肠道 cGAS 水平。通过 qPCR、WB 分析、H&E、IF 和 TUNEL 染色研究 cGAS KO 和 WT 小鼠中的自噬和细胞死亡机制。通过 WB 分析测量刺激的肠上皮细胞(IECs)中的自噬。我们的数据表明 cGAS 在人类和鼠结肠炎期间上调。此外,cGAS 缺乏导致结肠炎恶化和自噬蛋白(包括 Beclin-1 和 LC3-II)水平降低。Co-IP 表明 cGAS 和 Beclin-1 在 IECs 中直接结合。转染刺激的 HCT-116 细胞中的 cGAS 导致自噬增加。从 cGAS KO 中分离的 IECs 的自噬通量降低。用 DSS 处理 cGAS KO 小鼠会导致细胞死亡增加和 cleaved caspase-3 增加。最后,用雷帕霉素处理 cGAS KO 小鼠可降低结肠炎的严重程度。我们的数据表明,cGAS 通过上调 Beclin-1 介导的自噬并防止 IEC 死亡,在人类 IBD 和鼠结肠炎期间维持肠道上皮细胞稳态。自噬的恢复可以减轻与 cGAS 缺乏相关的结肠炎的严重程度。