Mis-localized mitochondrial ribosomes guide ceramide-dependent mitophagy for inducing cell death via alterations of the bioenergetics and metabolism. Mis-localized mitochondrial ribosomes guide ceramide-dependent mitophagy for inducing cell death via alterations of the bioenergetics and metabolism

In this work, we set out experiments to determine the mechanisms that regulate mitochondrial trafficking of p17/PERMIT-CerS1 complex in response to Drp1 activation to induce mitophagy and cellular consequences of this process altering mitochondrial metabolism in cultured cells in situ and genetic mice models in vivo. The data revealed that mislocalized mitochondrial ribosomes on the outer membrane due to Drp1-mediated fission are recognized by p17/PERMIT for CerS1 localization leading to ceramide-dependent mitophagy in response to oxidative stress by the generation of nitric oxide species (NOS). This process then leads to mitochondrial dysfunction resulting in decreased malate/fumarate/aspartate exhaustion, which is restored and prevented by molecular and genetic ablation of p17/PERMIT, LC3, Drp1, and Parkin in cancer cells or patient-derived 2D-organoids or mice brains in response to SoSe or ceramide analog drug, LCL768. Overall design: Human Head and neck cancer cells have been treated with SoSe or LCL657, total RNA was extracted and loaded on the NanoString nCounter® Human Metabolic Pathways Panel.

本研究通过系列实验，探究了响应动力相关蛋白1（Drp1）激活、诱导线粒体自噬（mitophagy）的p17/PERMIT-神经酰胺合成酶1（CerS1）复合物的线粒体运输调控机制，同时分析了该过程在原位培养细胞与体内遗传小鼠模型中，改变线粒体代谢所产生的细胞效应。研究数据表明，因Drp1介导的线粒体分裂而在外膜上错误定位的线粒体核糖体，可被p17/PERMIT识别以介导CerS1的定位，进而在氧化应激条件下通过一氧化氮类物质（NOS）的生成，引发神经酰胺依赖性线粒体自噬。该过程随后会引发线粒体功能异常，导致苹果酸、延胡索酸与天冬氨酸的耗竭水平降低；而在癌细胞、患者来源的二维类器官（2D-organoids）或小鼠脑组织中，通过分子与遗传学手段敲除p17/PERMIT、LC3、Drp1与Parkin，可逆转并阻止这一表型，该干预对应SoSe或神经酰胺类似物LCL768的处理条件。实验整体设计：将人头颈癌细胞经SoSe或LCL657处理后，提取总RNA并加载至NanoString nCounter® 人类代谢通路检测板中。