BioISI-Biosystems and Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, 1749-016 Lisboa, Portugal.
Cells. 2022 Jul 25;11(15):2295. doi: 10.3390/cells11152295.
The plasma membrane (PM) stability of the cystic fibrosis transmembrane conductance regulator (CFTR), the protein which when mutated causes Cystic Fibrosis (CF), relies on multiple interaction partners that connect CFTR to signaling pathways, including cAMP signaling. It was previously shown that activation of exchange protein directly activated by cAMP 1 (EPAC1) by cAMP promotes an increase in CFTR PM levels in airway epithelial cells. However, the relevance of this pathway in other tissues, particularly the intestinal tissue, remains uncharacterized. Here, we used Western blot and forskolin-induced swelling assay to demonstrate that the EPAC1 protein is not expressed in the intestinal organoid model, and consequently the EPAC1 stabilization pathway is not in place. On the other hand, using cell surface biotinylation, EPAC1-mediated stabilization of PM CFTR is observed in intestinal cell lines. These results indicate that the EPAC1 stabilization pathway also occurs in intestinal cells and is a potential target for the development of novel combinatorial therapies for treatment of CF.
囊性纤维化跨膜电导调节因子（CFTR）的质膜（PM）稳定性依赖于多种将 CFTR 连接到信号通路的相互作用伙伴，包括 cAMP 信号通路。先前的研究表明，cAMP 激活直接激活交换蛋白 1（EPAC1）可促进气道上皮细胞中 CFTR PM 水平的增加。然而，该途径在其他组织（特别是肠道组织）中的相关性尚未确定。在这里，我们使用 Western blot 和 forskolin 诱导的肿胀测定法证明，EPAC1 蛋白在肠道类器官模型中不表达，因此 EPAC1 稳定途径不存在。另一方面，使用细胞表面生物素化，观察到 EPAC1 介导的 PM CFTR 的稳定在肠道细胞系中发生。这些结果表明，EPAC1 稳定途径也存在于肠道细胞中，是开发用于治疗 CF 的新型组合疗法的潜在靶点。
