A genome-wide RNAi screen reveals determinants of human embryonic stem cell identity
NATURE
Authors: Chia, Na-Yu; Chan, Yun-Shen; Feng, Bo; Lu, Xinyi; Orlov, Yuriy L.; Moreau, Dimitri; Kumar, Pankaj; Yang, Lin; Jiang, Jianming; Lau, Mei-Sheng; Huss, Mikael; Soh, Boon-Seng; Kraus, Petra; Li, Pin; Lufkin, Thomas; Lim, Bing; Clarke, Neil D.; Bard, Frederic; Ng, Huck-Hui
Abstract
The derivation of human ES cells (hESCs) from human blastocysts represents one of the milestones in stem cell biology(1). The full potential of hESCs in research and clinical applications requires a detailed understanding of the genetic network that governs the unique properties of hESCs. Here, we report a genome-wide RNA interference screen to identify genes which regulate self-renewal and pluripotency properties in hESCs. Interestingly, functionally distinct complexes involved in transcriptional regulation and chromatin remodelling are among the factors identified in the screen. To understand the roles of these potential regulators of hESCs, we studied transcription factor PRDM14 to gain new insights into its functional roles in the regulation of pluripotency. We showed that PRDM14 regulates directly the expression of key pluripotency gene POU5F1 through its proximal enhancer. Genome-wide location profiling experiments revealed that PRDM14 colocalized extensively with other key transcription factors such as OCT4, NANOG and SOX2, indicating that PRDM14 is integrated into the core transcriptional regulatory network. More importantly, in a gain-of-function assay, we showed that PRDM14 is able to enhance the efficiency of reprogramming of human fibroblasts in conjunction with OCT4, SOX2 and KLF4. Altogether, our study uncovers a wealth of novel hESC regulators wherein PRDM14 exemplifies a key transcription factor required for the maintenance of hESC identity and the reacquisition of pluripotency in human somatic cells.
Induced Pluripotent Stem Cells Derived From Two Idiopathic Azoospermia Patients Display Compromised Differentiation Potential for Primordial Germ Cell Fate
FRONTIERS IN CELL AND DEVELOPMENTAL BIOLOGY
Authors: Fang, Fang; Li, Zili; Zhao, Qian; Ye, Zhen; Gu, Xiuli; Pan, Feng; Li, Honggang; Xiang, Wenpei; Xiong, Chengliang
Abstract
At present, the etiology of most non-obstructive azoospermia (NOA) remains unclear.In vitrogeneration of patient-specific induced pluripotent stem cells (iPSCs) is an effective approach for exploring the mechanisms of human disease. Here, we established iPSCs from two patients with idiopathic NOA and differentiated them into primordial germ cell-like cells (PGCLCs)in vitro. Compared with iPSCs derived from normal fertile men, the NOA patient-specific iPSCs show decreased efficiency of PGCLC formationin vitro. Particularly, the embryoids derived from NOA patient-specific iPSCs show defects in the expression of early primordial germ cell (PGC) genes. The transcriptome analysis reveals the expression patterns of key human PGC genes are generally similar in PGCLCs differentiated from all iPSC lines, and the differentially expressed genes were enriched with gene ontology (GO) of cell cycle and apoptosis regulation. Moreover, the PGCLCs derived from NOA patient-specific iPSCs might have initiated epigenetic reprogramming at a very early stage. Thus, the NOA patient-specific iPSCs exhibit poor response to germ cell inductionin vitro, which may be related to the regulation of apoptotic process. These findings provide a foundation for future research on mechanism of male infertility.