Programmed switch in the mitochondrial degradation pathways during human retinal ganglion cell differentiation from stem cells is critical for RGC survival
Programmed switch in the mitochondrial degradation pathways during human retinal ganglion cell differentiation from stem cells is critical for RGC survival
复制标题
DOI：
10.1016/j.redox.2020.101465
复制
发表时间：
2020-07-01
期刊：
影响因子：
11.4
通讯作者：
Zack, Donald J.
中科院分区：
文献类型：
--
作者：
Das, Arupratan;Bell, Claire M.;Zack, Donald J.
视网膜神经节细胞（RGC）变性是青光眼以及其他形式的视神经病变导致视力丧失的根本原因。多种研究表明线粒体质量控制（MQC）异常会导致视神经病变中 RGC 损伤和变性。将人类多能干细胞 (hPSC) 分化为 RGC 的能力为详细研究 RGC MQC 提供了机会。受损线粒体的降解是 MQC 的关键步骤，在这里，我们使用 hPSC 衍生的 RGC (hRGC) 来分析 hRGC 中改变的线粒体降解途径如何影响其生存。使用药理学方法，我们研究了蛋白酶体和内溶酶体途径在降解 hRGC 及其前体干细胞中受损线粒体中的作用。我们发现，在质子解偶联剂羰基氰化物间氯苯腙（CCCP）诱导线粒体损伤时，hRGC 比其前体干细胞更有效地降解线粒体。我们进一步发现，为了降解受损的线粒体，干细胞主要使用泛素蛋白酶体系统（UPS），而 hRGC 使用内溶酶体途径。 UPS 抑制会导致干细胞凋亡和细胞死亡，而 hRGC 活力取决于内溶酶体途径，但不依赖于 UPS 途径。这些发现表明，在治疗与线粒体自噬缺陷相关的视神经病变时，操纵内溶酶体途径可能与 RGC 保护具有治疗相关性。内溶酶体依赖性细胞存活在其他人类神经元中也是保守的，因为我们发现分化的人类大脑皮层神经元也会在内溶酶体抑制时退化，但在蛋白酶体抑制时不会退化。
Retinal ganglion cell (RGC) degeneration is the root cause for vision loss in glaucoma as well as in other forms of optic neuropathy. A variety of studies have implicated abnormal mitochondrial quality control (MQC) as con- tributing to RGC damage and degeneration in optic neuropathies. The ability to differentiate human pluripotent stem cells (hPSCs) into RGCs provides an opportunity to study RGC MQC in great detail. Degradation of damaged mitochondria is a critical step of MQC, and here we have used hPSC-derived RGCs (hRGCs) to analyze how altered mitochondrial degradation pathways in hRGCs affect their survival. Using pharmacological methods, we have investigated the role of the proteasomal and endo-lysosomal pathways in degrading damaged mitochondria in hRGCs and their precursor stem cells. We found that upon mitochondrial damage induced by the proton uncoupler carbonyl cyanide m -chlorophenyl hydrazone (CCCP), hRGCs more efficiently degraded mitochondria than did their precursor stem cells. We further identified that for degrading damaged mitochondria, stem cells predominantly use the ubiquitine-proteasome system (UPS) while hRGCs use the endo-lysosomal pathway. UPS inhibition causes apoptosis and cell death in stem cells, while hRGC viability is dependent on the endo-lysosomal pathway but not on the UPS pathway. These findings suggest that manipulation of the endo-lysosomal pathway could be therapeutically relevant for RGC protection in treating optic neuropathies associated with mitophagy defects. Endo-lysosome dependent cell survival is also conserved in other human neurons as we found that differentiated human cerebral cortical neurons also degenerated upon endo-lysosomal inhibition but not with proteasome inhibition.