胞外体

胞外体

科技的进步为人类提供了工具去探索体内细胞更微小部分。

过程中,我们发现了这些信号器在辨认疾病、生物入侵健康和治疗疾病方面有强大作用。

胞外体就是其中一种具有深厚潜力影响衰老的信号。

什么是胞外体 (Exosome)?

Exosomes are nano-sized extracellular vesicles. Unlike intracellular signals, that function within the cells, exosomes travel in the extracellular fluid (like the blood), communicating from one cell to another. They are often referred to as membrane-bound vesicles and although not a cell, they have a surrounding wall protecting the contents it carries. To deliver its message, it fuses its membrane with the target cell’s wall, therefore spilling its contents before being recycled.

Discovered in the 1980s, exosomes were first thought to be cellular garbage bags carrying waste around. In reality, exosomes carry a wide range of material that is used in communication including various proteins, molecules and genetic material. In fact, by inspecting the contents of exosomes scientists can analyze the signals they are sending and distinguish healthy cells from diseased cells.

胞外体及衰老

作为主力的信号传递者,胞外体在加速或抗衰老过程中担当着重要角色。其中主要角色有: 

细胞衰老

随着年龄增长,许多细胞会受损,不能再健康地复制细胞。由于未能及时分解及回收,受损的细胞会继续主动传递对身体有害的信号。这些被称为衰老的细胞会释放更多的毒性胞外体,而这些胞外体将衰老的状态当作信息般传播到邻近的细胞,并加速引致炎症和癌症等慢性疾病。相反地​​科学家已经从遗传物质(miRNA)中识别出能有效抑制细胞衰老的胞外体信号。

2. 压力及衰老

研究表示,压力与胞外体传递信号的种类有直接的关系。这些信号就像危险警告一样,允许其他细胞响应给予的压力而事先进行先发制人的改变。尽管有效用,但在长期压力下,这些信号会促使炎症的环境,导致加速衰老和引致慢性疾病。

3. 有毒蛋白质

衰老的细胞可以通过胞外体,传递含毒性的蛋白质和mRNA的信号。这些信号不但能致病,更与神经退化障碍及因衰老的认知能力下降有关。

胞外体疗法

胞外体没有好坏之分,因为它们只是细胞之间的讯息传递者。而实质上,它们的存在是一个令人振奋的研究新领域,例如从衰老细胞中找出抑制负面信号传递的方法、 调节正面信号,在指定情况下利用生物骇客技术等。鉴于其广泛的应用和对衰老的可改变的能力,胞外体疗法绝对是抗衰老医学的崭新疗法。

研究显示,胞外体疗法具有以下功能:

  • 伤口愈合
  • 骨骼再生
  • 促进循环
  • 新血管形成(血管生成)
  • 激活 Nrf2 的抗氧化和抗炎功能

参考文献

  1. Panagiotou N, Neytchev O, Selman C, Shiels PG. Extracellular Vesicles, Ageing, and Therapeutic Interventions. Cells. 2018;7(8):110. Published 2018 Aug 18. doi:10.3390/cells7080110
  2. D’Anca M, Fenoglio C, Serpente M, Arosio B, Cesari M, Scarpini EA, Galimberti D. Exosome Determinants of Physiological Aging and Age-Related Neurodegenerative Diseases. Frontiers in Aging Neuroscience. 2019;11:232. 
  3. Bellingham, S. A., Guo, B. B., Coleman, B. M., and Hill, A. F. (2012). Exosomes: vehicles for the transfer of toxic proteins associated with neurodegenerative diseases? Front. Physiol. 3:124. doi: 10.3389/fphys.2012.00124
  4. Pusic, A. D., and Kraig, R. P. (2014). Youth and environmental enrichment generate serum exosomes containing miR-219 that promote CNS myelination. Glia 62, 284–299. doi: 10.1002/glia.22606
  5. Zhang J, Guan J, Niu X, Hu G, Guo S, Li Q, et al. Exosomes released from human induced pluripotent stem cells-derived MSCs facilitate cutaneous wound healing by promoting collagen synthesis and angiogenesis. J Transl Med. 2015;13:49.
  6. Zhang J, Liu X, Li H, Chen C, Hu B, Niu X, et al. Exosomes/tricalcium phosphate combination scaffolds can enhance bone regeneration by activating the PI3K/Akt signaling pathway. Stem Cell Res Ther. 2016;7(1):136.
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