目的:结肠细胞中氯化物转运体SLC26A3的下调最近与溃疡性结肠炎(UC)的发病机制有关。因为夸大的免疫反应是UC的标志之一,目前进行的这些研究是为了确定腺瘤中下调的缺失(DRA)将信号传递给免疫细胞以增加炎症易感性的机制.
方法:NanoString免疫学小组,荧光辅助细胞分选,免疫印迹,免疫荧光,在野生型和DRA敲除(KO)小鼠中使用定量实时聚合酶链反应测定。白细胞介素(IL)-33阻断用于确定免疫细胞和共住房/广谱抗生素给药的特异性变化,在结肠样中进行了离体研究,以排除微生物群的参与。分析了来自健康和UC患者活检的结肠样来源的单层的可翻译性。
结果:Th2有明显的诱导(p2倍),CD4+Th2细胞(~8倍),RORγt+Th17和FOXP3+调节性T细胞(Tregs)。DRA-KO结肠也表现出IL-33的强诱导(>8倍)。使用IL-33阻断的体内研究确定,响应于DRA损失的T2免疫失调(ILC2、Th2和GATA3+iTregs的改变)是由于通过IL-33改变的上皮-免疫细胞串扰。
结论:结肠细胞中DRA的丢失触发IL-33的释放以驱动T2免疫应答。这些观察结果强调了DRA在粘膜免疫稳态中的至关重要性及其在UC发病机理中的意义。
Down-regulation of chloride transporter SLC26A3 or down-regulated in adenoma (DRA) in colonocytes has recently been linked to the pathogenesis of ulcerative colitis (UC). Because exaggerated immune responses are one of the hallmarks of UC, these current studies were undertaken to define the mechanisms by which loss of DRA relays signals to immune cells to increase susceptibility to inflammation.
NanoString Immunology Panel, fluorescence assisted cell sorting, immunoblotting, immunofluorescence, and quantitative real-time polymerase chain reaction assays were used in wild-type and DRA knockout (KO) mice. Interleukin (IL)-33 blocking was used to determine specific changes in immune cells and co-housing/broad spectrum antibiotics administration, and ex vivo studies in colonoids were conducted to rule out the involvement of microbiota. Colonoid-derived monolayers from healthy and UC patient biopsies were analyzed for translatability.
There was a marked induction of Th2 (>2-fold), CD4+ Th2 cells (∼8-fold), RORγt+ Th17, and FOXP3+ regulatory T cells (Tregs). DRA KO colons also exhibited a robust induction of IL-33 (>8-fold). In vivo studies using blocking of IL-33 established that T2 immune dysregulation (alterations in ILC2, Th2, and GATA3+ iTregs) in response to loss of DRA was due to altered epithelial-immune cell crosstalk via IL-33.
Loss of DRA in colonocytes triggers the release of IL-33 to drive a type 2 immune response. These observations emphasize the critical importance of DRA in mucosal immune homeostasis and its implications in the pathogenesis of UC.