Senescent cells play a causative role in many diseases, and their elimination is a promising therapeutic strategy. Here, through a genome-wide CRISPR/Cas9 screen, we identify the gene PPIF, encoding the mitochondrial protein cyclophilin D (CypD), as a novel senolytic target. Cyclophilin D promotes the transient opening of the mitochondrial permeability transition pore (mPTP), which serves as a failsafe mechanism for calcium efflux. We show that senescent cells exhibit a high frequency of transient CypD/mPTP opening events, known as 'flickering'. Inhibition of CypD using genetic or pharmacologic tools, including cyclosporin A, leads to the toxic accumulation of mitochondrial Ca2+ and the death of senescent cells. Genetic or pharmacological inhibition of NCLX, another mitochondrial calcium efflux channel, also leads to senolysis, while inhibition of the main Ca2+ influx channel, MCU, prevents senolysis induced by CypD inhibition. We conclude that senescent cells are highly vulnerable to elevated mitochondrial Ca2+ ions, and that transient CypD/mPTP opening is a critical adaptation mechanism for the survival of senescent cells.

中文翻译：

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亲环蛋白 D 在衰老细胞的存活中起关键作用。


衰老细胞在许多疾病中起着致病作用，消除它们是一种很有前途的治疗策略。在这里，通过全基因组 CRISPR/Cas9 筛选，我们将编码线粒体蛋白亲环蛋白 D （CypD） 的基因 PPIF 鉴定为一种新的 senolytic 靶标。亲环蛋白 D 促进线粒体通透性转换孔 （mPTP） 的瞬时打开，这是钙外排的故障安全机制。我们表明衰老细胞表现出高频的瞬时 CypD/mPTP 开放事件，称为“闪烁”。使用遗传或药物工具（包括环孢菌素 A）抑制 CypD 会导致线粒体 Ca2+ 的毒性积累和衰老细胞的死亡。NCLX（另一种线粒体钙外排通道）的遗传或药理学抑制也会导致 senolysis，而抑制主要的 Ca2+ 内流通道 MCU 可防止 CypD 抑制诱导的 senolysis。我们得出结论，衰老细胞极易受到线粒体 Ca 2 + 离子升高的影响，瞬时 CypD/mPTP 开放是衰老细胞存活的关键驯化机制。