DPPA5 Supports Pluripotency and Reprogramming by Regulating NANOG Turnover.

Although a specific group of transcription factors such as OCT4, SOX2, and NANOG are known to play essential roles in pluripotent stem cell (PSC) self-renewal, pluripotency, and reprogramming, other factors and the key signaling pathways regulating these important properties are not completely understood. Here, we demonstrate that the PSC marker Developmental Pluripotency Associated 5 (DPPA5) plays an important role in human PSC (hPSC) self-renewal and cell reprogramming in feeder-free conditions. Compared to hPSCs grown on mouse embryonic fibroblasts, cells cultured on feeder-free substrates, such as Matrigel, Laminin-511, Vitronectin, or the synthetic polymer poly[2-(methacryloyloxy) ethyl dimethyl-(3-sulfopropyl) ammonium hydroxide], had significantly higher DPPA5 gene expression and protein levels. Overexpression of DPPA5 in hPSCs increased NANOG protein levels via a post-transcriptional mechanism. Coimmunoprecipitation, protein stability assays, and quantitative RT-PCR, demonstrated that DPPA5 directly interacted, stabilized, and enhanced the function of NANOG in hPSCs. Additionally, DPPA5 increased the reprogramming efficiency of human somatic cells to induced pluripotent stem cells (hiPSCs). Our study provides new insight into the function of DPPA5 and NANOG regulation in hPSCs.