Meir Michael, Kannapin Felix, Diefenbacher Markus, Ghoreishi Yalda, Kollmann Catherine, Flemming Sven, Germer Christoph-Thomas, Waschke Jens, Leven Patrick, Schneider Reiner, Wehner Sven, Burkard Natalie, Schlegel Nicolas
Department of General, Visceral, Vascular and Pediatric Surgery University Hospital Würzburg, Oberduerrbacherstrasse 6, 97080 Wuerzburg, Germany.
Department of Biochemistry and Molecular Biochemistry, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany.
Int J Mol Sci. 2021 Feb 14;22(4):1887. doi: 10.3390/ijms22041887.
Enteric glial cells (EGCs) of the enteric nervous system are critically involved in the maintenance of intestinal epithelial barrier function (IEB). The underlying mechanisms remain undefined. Glial cell line-derived neurotrophic factor (GDNF) contributes to IEB maturation and may therefore be the predominant mediator of this process by EGCs. Using GFAP x Ai14 mice to isolate EGCs by Fluorescence-activated cell sorting (FACS), we confirmed that they synthesize GDNF in vivo as well as in primary cultures demonstrating that EGCs are a rich source of GDNF in vivo and in vitro. Co-culture of EGCs with Caco2 cells resulted in IEB maturation which was abrogated when GDNF was either depleted from EGC supernatants, or knocked down in EGCs or when the GDNF receptor RET was blocked. Further, TNFα-induced loss of IEB function in Caco2 cells and in organoids was attenuated by EGC supernatants or by recombinant GDNF. These barrier-protective effects were blunted when using supernatants from GDNF-deficient EGCs or by RET receptor blockade. Together, our data show that EGCs produce GDNF to maintain IEB function in vitro through the RET receptor.
肠道神经系统的肠胶质细胞（EGCs）在维持肠道上皮屏障功能（IEB）中起关键作用。其潜在机制尚不清楚。胶质细胞系衍生的神经营养因子（GDNF）有助于IEB成熟，因此可能是EGCs介导这一过程的主要介质。利用GFAP x Ai14小鼠通过荧光激活细胞分选（FACS）分离EGCs，我们证实它们在体内和原代培养中均能合成GDNF，表明EGCs在体内和体外都是GDNF的丰富来源。EGCs与Caco2细胞共培养导致IEB成熟，当GDNF从EGC上清液中耗尽、在EGCs中敲低或GDNF受体RET被阻断时，这种成熟被消除。此外，EGC上清液或重组GDNF可减轻TNFα诱导的Caco2细胞和类器官中IEB功能的丧失。当使用来自GDNF缺陷型EGCs的上清液或通过RET受体阻断时，这些屏障保护作用减弱。总之，我们的数据表明，EGCs通过RET受体产生GDNF以在体外维持IEB功能。
