Laboratory of Molecular Medicine, Institute of Cytology of the Russian Academy of Sciences, Tikhoretsky Ave. 4, 194064 St-Petersburg, Russia.
Center of Transgenesis and Genome Editing, St. Petersburg State University, Universitetskaja Emb., 7/9, 199034 St-Petersburg, Russia.
Cells. 2023 Jan 13;12(2):304. doi: 10.3390/cells12020304.
G-protein-coupled receptors (GPCRs) are the largest family of cell surface receptors. They modulate key physiological functions and are required in diverse developmental processes including embryogenesis, but their role in pluripotency maintenance and acquisition during the reprogramming towards hiPSCs draws little attention. Meanwhile, it is known that more than 106 GPCRs are overexpressed in human pluripotent stem cells (hPSCs). Previously, to identify novel effectors of reprogramming, we performed a high-throughput RNA interference (RNAi) screening assay and identified adhesion GPCR, GPR123, as a potential reprogramming effector. Its role has not been explored before. Herein, by employing RNAi we addressed the role of GPR123 for hPSCs. The suppression of in hPSCs leads to the loss of pluripotency and differentiation, impacted colony morphology, accumulation of cells at the G2 phase of the cell cycle, and absence of the scratch closure. Application of the RNAi at the initiation stage of reprogramming leads to a decrease in the percentage of the "true" hiPSC colonies, a drop in E-cadherin expression, a decrease in the percentage of NANOG+ nuclei, and the absence of actin cytoskeleton remodeling. Together this leads to the absence of the alkaline-phosphatase-positive hiPSCs colonies on the 18th day of the reprogramming process. Overall, these data indicate for the first time the essential role of GPR123 in the maintenance and acquisition of pluripotency.
G 蛋白偶联受体（GPCRs）是细胞表面受体中最大的家族。它们调节关键的生理功能，并且在包括胚胎发生在内的各种发育过程中是必需的，但它们在重编程为 hiPSCs 过程中维持和获得多能性方面的作用却很少受到关注。与此同时，已知超过 106 种 GPCR 在人类多能干细胞（hPSCs）中过表达。此前，为了鉴定重编程的新效应物，我们进行了高通量 RNA 干扰（RNAi）筛选实验，鉴定出黏附 GPCR、GPR123，作为一种潜在的重编程效应物。其作用以前尚未被探索过。在此，我们通过 RNAi 来研究 GPR123 在 hPSCs 中的作用。在 hPSCs 中抑制 GPR123 会导致多能性丧失和分化，影响集落形态，细胞在细胞周期的 G2 期积累，以及划痕闭合缺失。在重编程的起始阶段应用 RNAi 会导致“真正”hiPSC 集落的百分比降低，E-钙粘蛋白表达下降，NANOG+核的百分比降低，以及肌动蛋白细胞骨架重构缺失。总之，这导致碱性磷酸酶阳性 hiPSC 集落在重编程过程的第 18 天缺失。总的来说，这些数据首次表明 GPR123 在维持和获得多能性方面的重要作用。
