Connecting lysosomes and mitochondria - a novel role for lipid metabolism in cancer cell death
Connecting lysosomes and mitochondria - a novel role for lipid metabolism in cancer cell death
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DOI：
10.1186/s12964-019-0399-2
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发表时间：
2019-07-29
影响因子：
8.4
通讯作者：
von Schwarzenberg, Karin
中科院分区：
文献类型：
--
作者：
Bartel, Karin;Pein, Helmut;von Schwarzenberg, Karin
在最近的研究中，对溶酶体的理解已经超越了它们作为细胞垃圾桶的观点。溶酶体在调节代谢、内吞作用和自噬中起关键作用，并与癌症有关。近年来，人们发现溶酶体v - atp酶能够诱导肿瘤细胞凋亡，并干扰肿瘤细胞的脂质代谢，但这些细胞器之间的相互作用尚不清楚。方法采用slc -MS/MS分析细胞内脂质分布。采用细胞生物学方法（qPCR、Western Blot、流式细胞术、CellTiter-Blue）分析细胞存活和信号通路。用共聚焦成像和电镜分析线粒体结构，用流式细胞术和海马测量法测定线粒体功能。结果我们的数据显示，干扰溶酶体功能会改变甘油三酯的组成和亚细胞定位，并伴有PGC1 α和PPAR α表达上调，而PGC1 α和PPAR α是能量和脂质代谢的主要调节因子。此外，心磷脂含量的降低导致线粒体发生裂变，同时伴随着膜电位的丧失和氧化能力的降低，从而导致细胞ROS的失调，并诱导线粒体驱动的细胞凋亡。此外，细胞经历了谷氨酰胺依赖的代谢转变，这与裂变表型和对溶酶体抑制的敏感性相关，在Ras突变细胞中最为突出。结论：该研究揭示了溶酶体、脂质代谢和线粒体功能之间一个尚未被研究的三角关系的机制。对这种细胞器串扰的深入了解增加了我们对线粒体驱动的细胞死亡的理解。我们的研究结果进一步提供了Ras通路突变和对溶酶体抑制剂敏感性之间联系的第一个线索。
BackgroundThe understanding of lysosomes has been expanded in recent research way beyond their view as cellular trash can. Lysosomes are pivotal in regulating metabolism, endocytosis and autophagy and are implicated in cancer. Recently it was discovered that the lysosomal V-ATPase, which is known to induce apoptosis, interferes with lipid metabolism in cancer, yet the interplay between these organelles is poorly understood.MethodsLC-MS/MS analysis was performed to investigate lipid distribution in cells. Cell survival and signaling pathways were analyzed by means of cell biological methods (qPCR, Western Blot, flow cytometry, CellTiter-Blue). Mitochondrial structure was analyzed by confocal imaging and electron microscopy, their function was determined by flow cytometry and seahorse measurements.ResultsOur data reveal that interfering with lysosomal function changes composition and subcellular localization of triacylglycerids accompanied by an upregulation of PGC1 alpha and PPAR alpha expression, master regulators of energy and lipid metabolism. Furthermore, cardiolipin content is reduced driving mitochondria into fission, accompanied by a loss of membrane potential and reduction in oxidative capacity, which leads to a deregulation in cellular ROS and induction of mitochondria-driven apoptosis. Additionally, cells undergo a metabolic shift to glutamine dependency, correlated with the fission phenotype and sensitivity to lysosomal inhibition, most prominent in Ras mutated cells.ConclusionThis study sheds mechanistic light on a largely uninvestigated triangle between lysosomes, lipid metabolism and mitochondrial function. Insight into this organelle crosstalk increases our understanding of mitochondria-driven cell death. Our findings furthermore provide a first hint on a connection of Ras pathway mutations and sensitivity towards lysosomal inhibitors.