BRG1 has been found to promote the generation of induced pluripotent stem cells (iPSCs) by regulating epigenetic modifications or binding to transcription factors, however, the role of BRG1 on the cellular metabolism during reprogramming has not been reported. In this study, we found that BRG1 improved the efficiency of porcine iPSC generation, and upregulated the expression of pluripotency-related factors. Further analysis revealed that BRG1 promoted cellular glycolysis, and increased levels of glycolysis-related metabolites. It enhanced the transcriptional activity of glycolysis-related gene HK2, PKM2, and PFK-1 promoters, and decreased the enrichment of H3K9me3 in glycolysis- and pluripotency-related gene promoters. BRG1 also increased the phosphorylation level at the Ser473 site of AKT protein. The specific PI3K/AKT signaling pathway inhibitor, LY294002, impaired the generation of porcine iPSCs, downregulated the expression of pluripotency-related factors, and inhibited cellular glycolysis, overexpressing BRG1 rescued those changes caused by LY294002 treatment. In addition, the glycolysis inhibitor 2-DG and BRG1 inhibitor PFI-3 had similar effects to LY294002. The above results suggest that overexpression of BRG1 promotes the generation of porcine iPSCs by facilitating glycolytic reprogramming through the PI3K/AKT signaling pathway.
Xuan Ren,Jianchun Xu,Qingsong Xue,Yi Tong,Tairan Xu,Jinli Wang,Ting Yang,Yuan Chen,Deshun Shi,Xiangping Li
Brahma-related gene 1 (BRG1) enhances the pluripotency of embryonic and adult stem cells , however, its effect on induced pluripotent stem cell (iPSC) pluripotency has not been reported. The aim of this study was to investigate the effect of BRG1 on porcine iPSC pluripotency and its mechanisms. The effect of BRG1 on porcine iPSC pluripotency was explored by positive and negative control it. The mechanism was investigated by regulating the WNT/β-catenin signaling pathway and autophagy flux. The results showed that inhibition of BRG1 decreased pluripotency-related gene expression in porcine iPSCs; while its overexpression had the opposite effect, the expression of WNT/β-catenin signaling pathway- and autophagy-related genes was significantly up-regulated ( P < 0.05) in the BRG1 overexpressed group when compared to the control group. Inhibited pluripotency-related gene or protein expression , decreased autophagy flux, and increased mitochondrial length and mitochondrial membrane potential (MMP) were observed when porcine iPSCs were treated with the WNT/β-catenin signaling pathway inhibitor IWR-1. Forced BRG1 expression restored porcine iPSC pluripotency, increased autophagy flux, shortened mitochondria, and reduced MMP. Lastly, Compound C was used to activate porcine iPSC autophagy, and it was found that the expression of BRG1 and β-catenin increased, and pluripotency-related gene and protein expression was up-regulated; these effects were reversed when the BRG1 inhibitor PFI-3 and IWR-1 were added. These results suggested that BRG1 enhanced the pluripotency of porcine iPSCs through WNT/β-catenin and autophagy pathways.
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