Critical role of lysosomes in the dysfunction of human Cardiac Stem Cells obtained from failing hearts
Critical role of lysosomes in the dysfunction of human Cardiac Stem Cells obtained from failing hearts
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DOI：
10.1016/j.ijcard.2016.04.155
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发表时间：
2016-08-01
影响因子：
3.5
通讯作者：
Beltrami, Antonio Paolo
中科院分区：
文献类型：
--
作者：
Gianfranceschi, Giuseppe;Caragnano, Angela;Beltrami, Antonio Paolo
从移植的衰竭心脏 (E-) 中培养的心脏干细胞 (CSC) 的体内修复潜力会因细胞衰老而受损。此外，相对于从健康供体（D-）获得的CSC，E-CSC的特征在于自噬降解的停滞。尽管溶酶体在细胞稳态中发挥着关键作用，并且该细胞器的缺陷可能与衰老和心力衰竭有关，但 CSC 的溶酶体功能从未被研究过。这项工作的目的是关注 E-CSC 的溶酶体区室 (LC)，评估可能危害溶酶体功能的元素。方法和结果：对 D-CSC 和 E-CSC 之间差异表达的基因进行生物信息学分析，发现溶酶体相关基因集显着富集。此外，29个差异表达基因是CLEAR（协调溶酶体表达和调节）基因网络的一部分，转录因子EB（TFEB）通过该网络调节细胞清除。活细胞成像和流式细胞术分析一致表明，E-CSC 溶酶体的酸性低于 D-CSC 溶酶体。此外，共聚焦显微镜在 E-CSC 中显示：溶酶体内脂褐质的积累、组织蛋白酶 B 活性的降低、溶酶体膜透化的证据以及核活性 TFEB 的减少。使用雷帕霉素（TORC1 抑制剂）一方面能够增加 TFEB 激活，另一方面能够减少脂褐素质量，增强溶酶体功能。 结论：这项研究首次证明 E-CSC 的特点是 TFEB 激活减弱和蛋白质稳态改变。 TORC1 过度激活在这一现象中发挥着核心作用。 (C) 2016 Elsevier Ireland Ltd. 保留所有权利。
The in vivo reparative potential of Cardiac Stem Cells (CSC), cultured from explanted failing hearts (E-), is impaired by cellular senescence. Moreover, E-CSC are characterized, with respect to CSC obtained from healthy donors (D-), by an arrest in the autophagic degradation. Although the lysosome plays a pivotal role in cellular homeostasis and defects of this organelle may be associated with aging and heart failure, the lysosomal function of CSC has never been investigated. The aim of this work was to focus on the Lysosomal Compartment (LC) of E-CSC, evaluating elements that could jeopardize lysosome functionality.Methods and results: Bioinformatics analysis conducted on genes differentially expressed between D-and E-CSC identified lysosomal-related gene sets as significantly enriched. Moreover, 29 differentially expressed genes were part of CLEAR (Coordinated Lysosomal Expression and Regulation) gene network, by which Transcription Factor EB (TFEB) regulates cellular clearance. Consistently, live cell imaging and flow cytometry analyses showed that the lysosomes of E-CSC are less acidic than the D-CSC ones. Furthermore, confocal microscopy showed in E-CSC: an accumulation of intralysosomal lipofuscins, a reduction of cathepsin B activity, evidence of lysosome membrane permeabilization, and the reduction of the nuclear active TFEB. The use of Rapamycin (TORC1 inhibitor) was able on one hand to increase TFEB activation and, on the other hand, to reduce lipofuscin mass, potentiating the lysosomal functionality.Conclusions: This study demonstrated for the first time that E-CSC are characterized by a blunted activation of TFEB and an altered proteostasis. TORC1 hyperactivation plays a central role in this phenomenon. (C) 2016 Elsevier Ireland Ltd. All rights reserved.