Nuclear Medicine Division, Department of Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
Int J Mol Sci. 2013 Jul 29;14(8):15695-723. doi: 10.3390/ijms140815695.
Human stem cells (hSC) possess several distinct characteristics that set them apart from other cell types. First, hSC are self-renewing, capable of undergoing both asymmetric and symmetric cell divisions. Second, these cells can be coaxed to differentiate into various specialized cell types and, as such, hold great promise for regenerative medicine. Recent progresses in hSC biology fostered the characterization of the responses of hSC to genotoxic stresses, including ionizing radiation (IR). Here, we examine how different types of hSC respond to IR, with a special emphasis on their radiosensitivity, cell cycle, signaling networks, DNA damage response (DDR) and DNA repair. We show that human embryonic stem cells (hESCs) possess unique characteristics in how they react to IR that clearly distinguish these cells from all adult hSC studied thus far. On the other hand, a manifestation of radiation injuries/toxicity in human bodies may depend to a large extent on hSC populating corresponding tissues, such as human mesenchymal stem cells (hMSC), human hematopoietic stem cells (hHSC), neural hSC, intestine hSC, etc. We discuss here that hSC responses to IR differ notably across many types of hSC which may represent the distinct roles these cells play in development, regeneration and/or maintenance of homeostasis.
人类干细胞 (hSC) 具有几个独特的特征，使其与其他细胞类型区分开来。首先，hSC 具有自我更新的能力，能够进行不对称和对称的细胞分裂。其次，这些细胞可以被诱导分化为各种特化的细胞类型，因此在再生医学中具有很大的应用前景。hSC 生物学的最新进展促进了对 hSC 对遗传毒性应激（包括电离辐射 (IR)）的反应的特征描述。在这里，我们研究了不同类型的 hSC 对 IR 的反应，特别强调了它们的放射敏感性、细胞周期、信号网络、DNA 损伤反应 (DDR) 和 DNA 修复。我们表明，人类胚胎干细胞 (hESC) 在对 IR 的反应方面具有独特的特征，这些特征明显将这些细胞与迄今为止研究的所有成体 hSC 区分开来。另一方面，人体的辐射损伤/毒性表现可能在很大程度上取决于相应组织中存在的 hSC，例如人骨髓间充质干细胞 (hMSC)、人造血干细胞 (hHSC)、神经 hSC、肠道 hSC 等。我们在这里讨论 hSC 对 IR 的反应在许多类型的 hSC 中存在显著差异，这可能代表这些细胞在发育、再生和/或维持内稳态中发挥的不同作用。
