中国神经再生研究(英文版) ›› 2022, Vol. 17 ›› Issue (1): 105-107.doi: 10.4103/1673-5374.314301

• 观点:脑损伤修复保护与再生 • 上一篇    下一篇

缺氧诱导因子和早发性脑弥漫性白质损伤:小鼠基因研究

  

  • 出版日期:2022-01-05 发布日期:2021-09-18

Hypoxia inducible factor and diffuse white matter injury in the premature brain: perspectives from genetic studies in mice

Fuzheng Guo*, Sheng Zhang    

  1. Department of Neurology, School of Medicine, the University of California, Davis; Institute for Pediatric Regenerative Medicine (IPRM), Shriners Hospitals for Children, Northern California, Sacramento, CA, USA
  • Online:2022-01-05 Published:2021-09-18
  • Contact: Fuzheng Guo, PhD, fzguo@ucdavis.edu.
  • Supported by:
    The present work was supported by NIH/NINDS (R21NS109790 and R01NS094559) (to FG) and Shriners Hospitals for Children (85107-NCA-19 to FG, and 84307-NCAL to SZ).

摘要: Neural Regen Res:缺氧诱导因子与中枢神经系统髓鞘的形成
缺氧诱导因子(HIFs)是转录调节因子,在适应各种细胞适应生理和病理性缺氧提示方面起着重要作用。HIFα在调节多种生物过程中的作用主要是通过其下游靶基因和/或信号通路。前期研究表明,HIF1α和HIF2α在细胞类型和上下文依赖方式中激活了共同(典型)和明显(非规范)的目标基因集。HIFα(HIF1α和HIF2α)在胚胎发育中的重要性表现为HIF1α-/-小鼠和HIF2α-/-小鼠因心血管和肺畸形而导致的早期胚胎或新生儿的致死性。中枢神经系统的生理缺氧环境提示HIFα在神经发育中起重要作用。神经细胞特异性的、基于Cre-loxP的、由Nestin-Cre驱动的HIFα条件敲除突变小鼠已经证明了HIFα在神经发育中的必要性,从而避免了HIFα种系敲除突变体的早期致死性。Nestin启动子在产生神经元和胶质细胞的早期神经祖细胞中是活跃的。HIF2α条件敲除小鼠的神经表型似乎比HIF1α条件敲除突变体的神经表型温和得多。证明了HIFα在神经发育中的重要作用。 
    来自美国加州大学戴维斯分校医学院的Fuzheng Guo团队认为HIFα调节一组对能量代谢和供应(如葡萄糖转运、糖酵解和血管生成)至关重要的共同标准靶基因,并参与保护细胞免受缺氧和其他不利提示的适应性反应。理论上,靶向HIFα本身可能干扰这些关键的细胞过程和适应性机制。在缺氧/缺血诱导的弥漫性脑白质损伤的背景下,发现HIFα的新非规范下游靶点或通路以减轻少突胶质细胞祖细胞分化的阻滞是非常重要的。当前流行的假说来源于正常发育研究,提出HIFα通过激活自分泌Wnt/β-catenin信号来控制少突胶质细胞祖细胞分化。这是一个非常诱人的工作模型,因为它可以解释在受脑室周围白质软化影响的早产儿和受缺氧缺血性脑病影响的成熟婴儿的脑白质少突胶质细胞系细胞中观察到的Wnt/β-连环蛋白信号的过度活跃。从星形胶质细胞特异性HIFα稳定小鼠获得的数据表明星形胶质细胞HIFα可能通过旁分泌方式激活少突胶质细胞系中的Wnt/β-catenin信号来控制少突胶质细胞祖细胞分化和髓鞘形成。虽然已知细胞内Wnt/β-catenin信号的过度激活抑制少突胶质细胞祖细胞分化,但在少突胶质细胞祖细胞中启动细胞内Wnt/β-catenin活性的Wnt配体的细胞来源仍有待研究。从治疗的角度来看,在配体水平操纵细胞内Wnt/β-catenin信号轴比在细胞内水平更为可行。未来的研究,特别是那些采用细胞特异性小鼠遗传学的研究,需要通过星形胶质细胞衍生/HIFα调节Wnt的产生来测试少突胶质细胞祖细胞分化的假设“旁分泌”调节。
     文章在《中国神经再生研究(英文版)》杂志2022年 1 月 1  期发表。

https://orcid.org/0000-0003-3410-8389 (Fuzheng Guo) 

Abstract: Hypoxia-inducible factors (HIFs) are transcriptional regulators playing important roles in adapting various types of cells to physiological and pathological hypoxia cues. Three structurally related, oxygen-sensitive HIFα proteins have been identified (HIF1α, HIF2α, and HIF3α), among which HIF3α has weak transcriptional capacity because of the absence of the C-terminal transactivation domain as present in HIF1α and HIF2α. The role of HIFα in regulating diverse biological processes is primarily through the actions of its downstream target genes and/or signaling pathways (Figure 1). The HIFα signaling is subjected to regulation at the multiple levels as detailed in Figure 1. Previous studies have shown that HIF1α and HIF2α activate both common (canonical) and distinct (non-canonical) sets of target genes in cell-type and context dependent manners. The importance of HIFα (HIF1α and HIF2α) in embryonic development is manifested by the lethality of early embryos or neonates of HIF1α–/– mice and HIF2α–/– mice due to the cardiovascular and lung malformation. In the developing central nervous system (CNS) where the maturation of the vascular network is still ongoing, the local oxygen concentration ranges from 0.5% to 7% (Ivanovic, 2009). The physiologically hypoxic environment in the CNS suggests that HIFα may play an important role in neural development.