Department of Structural Pathology Institute of Nephrology, Graduate School of Medical and Dental Sciences, Niigata University, Tokyo, Japan.
Stem Cell Rev Rep. 2014 Aug;10(4):561-72. doi: 10.1007/s12015-014-9517-0.
Embryonic stem cells (ESCs) have the ability to self-renew indefinitely and they can give unlimited source of cells and tissues for cellular therapies. Recently, the natriuretic peptide receptor A (NPR-A) has been recognized as an important regulator for the self-renewal of ESCs. To gain insights into possible novel mechanisms involved in NPR-A pathway that presumably regulates self-renewal and survival of ESCs, we utilized a comprehensive label-free proteomics technology in our study. Targeting of NPR-A gene with small interfering RNA (siRNA) resulted in the inhibition of ESCs self-renewal. Coherently, quantitative label-free shotgun proteomic analysis identified differentially expressed proteins involved in several biological processes, including cell cycle regulation, cell proliferation, cell fate specification, and apoptosis. Interestingly, in addition to Oct4 Nanog, and Sox2, other proteins involved in ESCs self-renewal were down-regulated after NPR-A knockdown, such as heterogeneous nuclear ribonucleoprotein A2/B1 (ROA2), non-POU domain-containing octamer-binding protein (Nono), nucleoplasmin (Npm1), histone H2A type 1-B/E (histone H2A.2), SW1/SNF complex (Brg1), polycomb protein Suz12 (Suz12), and cyclin-dependent kinase 4 (Cdk4). Furthermore, several protein candidates involved in early differentiation and cell death were up-regulated or down-regulated as a result of NPR-A knockdown, including importin subunit alpha-4 (Impα4), importin-5 (Ipo5), H3 histones, core histone macro-H2A.1 (H2A.y), apurine/apyrimidine endonuclease 1 (Apex1), 78-kDa glucose-regulated protein (Grp78), and programmed cell death 5 (Pdcd5). Overall, these findings depict a comprehensive view to our understanding of the pathways involved in the role of NPR-A in maintaining ESC functions.
胚胎干细胞（ESCs）具有无限自我更新的能力，它们可以为细胞治疗提供无限来源的细胞和组织。最近，利钠肽受体 A（NPR-A）已被认为是调节 ESC 自我更新的重要调节剂。为了深入了解 NPR-A 途径中可能涉及的调节 ESC 自我更新和存活的新机制，我们在研究中利用了全面的无标记蛋白质组学技术。用小干扰 RNA（siRNA）靶向 NPR-A 基因导致 ESCs 自我更新受到抑制。一致地，定量无标记 shotgun 蛋白质组学分析鉴定出涉及几个生物学过程的差异表达蛋白，包括细胞周期调控、细胞增殖、细胞命运特化和细胞凋亡。有趣的是，除了 Oct4、Nanog 和 Sox2 之外，NPR-A 敲低后，其他参与 ESCs 自我更新的蛋白也下调，如异质性核核糖核蛋白 A2/B1（ROA2）、非 POUS 域结合八聚体结合蛋白（Nono）、核磷蛋白（Npm1）、组蛋白 H2A 型 1-B/E（组蛋白 H2A.2）、SW1/SNF 复合物（Brg1）、多梳蛋白 Suz12（Suz12）和细胞周期蛋白依赖性激酶 4（Cdk4）。此外，由于 NPR-A 敲低，几个涉及早期分化和细胞死亡的蛋白候选物上调或下调，包括输入蛋白亚单位α-4（Impα4）、输入蛋白-5（Ipo5）、H3 组蛋白、核心组蛋白巨 H2A.1（H2A.y）、嘌呤/嘧啶内切核酸酶 1（Apex1）、78kDa 葡萄糖调节蛋白（Grp78）和程序性细胞死亡 5（Pdcd5）。总的来说，这些发现描绘了一幅全面的图景，使我们能够深入了解 NPR-A 在维持 ESC 功能中的作用所涉及的途径。
