Autophagy is Required for the Maintenance of Liver Progenitor Cell Functionality
Autophagy is Required for the Maintenance of Liver Progenitor Cell Functionality
复制标题
自噬是维持肝祖细胞功能所必需的
DOI：
10.1159/000430287
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发表时间：
2015-01-01
影响因子：
--
通讯作者：
Zhang, Yanyun
中科院分区：
文献类型：
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作者：
Cheng, Yiji;Wang, Bei;Zhang, Yanyun
背景资料：肝祖细胞（Liver progenitor cells，LPCs）是存在于成人肝脏中的双能干细胞，在严重肝损伤时可被激活并促进肝再生。然而，LPC功能的维持机制仍然知之甚少。先前的研究发现，自噬是几种组织干细胞自我更新和分化所必需的。方法：比较LPCs和分化肝细胞的自噬活性。然后，通过慢病毒介导的自噬相关基因5或Beclin 1敲低抑制LPC中的自噬活性。通过克隆形成试验、细胞活力试验、肝分化试验和衰老分析来评估自噬在调节LPC的自我更新、肝分化和衰老中的作用。结果：与分化的肝细胞相比，我们观察到高自噬活性的LPCs。我们发现在正常培养条件下，自噬的抑制损害了LPCs的自我更新、增殖和肝分化能力，但对细胞活力影响不大。有趣的是，虽然野生型LPC仍然很少受到毒素依托泊苷的影响，但抑制自噬诱导LPC的衰老表型。在Beclin 1敲低的LPC中Beclin 1的过表达恢复了干细胞的功能。结论：我们的研究结果表明，自噬可能作为一个重要的调节LPC功能的生理和病理条件下。
Background: Liver progenitor cells (LPCs) are bipotent stem cells existing in the adult liver, which could be activated upon massive liver injury and contribute to liver regeneration. However, mechanisms of maintenance of LPC functionality remain poorly understood. Previous studies found that autophagy was required for the self-renewal and differentiation of several tissue stem cells. Methods: The study compared the level of autophagic activity in LPCs and differentiated hepatocytes. Then, autophagic activity was inhibited in LPCs by lentivirus-mediated autophagy-related gene 5 or Beclin 1 knockdown. Clonogenic assay, cell viability assays, hepatic differentiation assay, and senescence analysis were conducted to assess the role of autophagy in regulating self-renewal, hepatic differentiation and senescence of LPCs. Results: We observed high autophagic activity in LPCs compared with differentiated hepatocytes. We found that inhibition of autophagy impaired the self-renewal, proliferation, and hepatic differentiation capability of LPCs under normal cultural condition, but had little impact on cell viability. Interestingly, while wild-type LPCs remained rarely affected by the toxin, etoposide, inhibition of autophagy induced the senescent phenotype of LPCs. Overexpression of Beclin 1 in Beclin 1-knockdown LPCs restored the functionality of stem cells. Conclusion: Our findings indicate that autophagy may function as a critical regulator of LPC functionality under both physiological and pathological condition.