缺氧通过缺氧诱导因子-1α-TWIST-p21 轴抑制细胞衰老，恢复老年人类内皮祖细胞的治疗潜能。
Hypoxia inhibits cellular senescence to restore the therapeutic potential of old human endothelial progenitor cells via the hypoxia-inducible factor-1α-TWIST-p21 axis.
机构信息
From the Laboratory for Vascular Medicine and Stem Cell Biology, Medical Research Institute, Department of Physiology, School of Medicine, Pusan National University, Yangsan, Korea (S.H.L., J.H.L., S.Y.Y., S.M.K.); Immunoregulatory Therapeutics Group in Brain Busan 21 Project (S.H.L., J.H.L., S.Y.Y., S.M.K.), Department of Medical Biolotechnology (S.H.L.), Soonchunhyang University College of Medicine, Seoul, Korea; National Research Laboratory for Cardiovascular Stem Cell Niche, Innovative Research Institute for Cell Therapy (J.H., H.S.K.), Cardiovascular Center and Department of Internal Medicine, Seoul National University Hospital, and Molecular Medicine and Biopharmaceutical Sciences, Seoul National University, Seoul, Korea (H.S.K.).
出版信息
Arterioscler Thromb Vasc Biol. 2013 Oct;33(10):2407-14. doi: 10.1161/ATVBAHA.113.301931. Epub 2013 Aug 8.
OBJECTIVE
Endothelial progenitor cells (EPCs) can significantly improve tissue repair by providing regeneration potential within injured cardiovascular tissue; however, it is challenging to obtain a sufficient amount of functional EPCs from aged patients for autologous stem cell therapy. To overcome this issue, we aimed to establish adequate ex vivo expansion protocols and identify repair modulators of cellular senescence. The senescence repair circuit of hypoxia-preconditioned senescent EPCs (hyp-old EPCs) was examined in an effort to enhance their regenerative potential.
APPROACH AND RESULTS
Long-term culturing of EPCs in normoxic conditions markedly induced the expression of p21, whereas siRNA targeting of p21 in old EPCs significantly enhanced the proliferation potential of cells. Hyp-old EPCs displayed increased hypoxia-inducible factor-1α and TWIST expression. siRNA inhibition of TWIST, a target molecule of the hypoxia-inducible factor-1α, markedly upregulated the expression of p21 in hyp-old EPCs by reprogramming cell-cycle regulatory proteins. In a hindlimb model of ischemia, the transplantation of hyp-old EPCs enhanced the blood flow ratio and capillary density, improved cellular proliferation and cell survival at ischemic sites, and augmented the secretion of pivotal tissue angiogenic cytokines. It has been previously demonstrated that the restoration of old EPCs from a senescent state by hypoxia preconditioning is tightly mediated by the downregulation of p21 via the hypoxia-inducible factor-1α-TWIST axis.
CONCLUSIONS
This study introduces ex vivo expansion protocols involving hypoxic preconditioning that are suitable for efficiently expanding old EPCs without senescence through modulation of the hypoxia-induced hypoxia-inducible factor-1α-TWIST-p21 axis. In addition, the expanded cells are shown to be useful for therapeutic vasculogenesis.
目的
内皮祖细胞（EPCs）通过为受损心血管组织内提供再生潜能，可显著改善组织修复；然而，从老年患者中获得足够数量的功能正常的 EPCs 用于自体干细胞治疗具有挑战性。为了解决这个问题，我们旨在建立充足的体外扩增方案，并确定细胞衰老的修复调节剂。本研究旨在探究缺氧预处理衰老的 EPCs（hyp-old EPCs）的衰老修复回路，以增强其再生潜能。
方法和结果
在常氧条件下长期培养 EPCs 会显著诱导 p21 的表达，而用 p21 的 siRNA 靶向作用于衰老的 EPCs 则会显著增强细胞的增殖潜能。hyp-old EPCs 表现出更高水平的缺氧诱导因子-1α和 TWIST 的表达。用 siRNA 抑制 TWIST（缺氧诱导因子-1α的靶分子），通过重编程细胞周期调节蛋白，可显著上调 hyp-old EPCs 中的 p21 表达。在缺血性后肢模型中，移植 hyp-old EPCs 可提高血流比率和毛细血管密度，改善缺血部位的细胞增殖和细胞存活，并增加关键组织血管生成细胞因子的分泌。先前的研究表明，通过缺氧预处理使衰老的 EPCs 恢复活力，是通过缺氧诱导因子-1α-TWIST-p21 轴下调 p21 来实现的。
结论
本研究提出了涉及缺氧预处理的体外扩增方案，通过调节缺氧诱导的缺氧诱导因子-1α-TWIST-p21 轴，可以有效地在不引起衰老的情况下扩增老年 EPCs。此外，还表明扩增后的细胞可用于治疗性血管生成。
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