Division of Nephrology.
Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
JCI Insight. 2019 Mar 14;5(8):126749. doi: 10.1172/jci.insight.126749.
Because injured mitochondria can accelerate cell death through the elaboration of oxidative free radicals and other mediators, it is striking that proliferator gamma coactivator 1-alpha (PGC1α), a stimulator of increased mitochondrial abundance, protects stressed renal cells instead of potentiating injury. Here we report that PGC1α's induction of lysosomes via transcription factor EB (TFEB) may be pivotal for kidney protection. CRISPR and stable gene transfer showed that PGC1α knockout tubular cells were sensitized to the genotoxic stressor cisplatin whereas transgenic cells were protected. The biosensor mtKeima unexpectedly revealed that cisplatin blunts mitophagy both in cells and mice. PGC1α not only counteracted this effect but also raised basal mitophagy, as did the downstream mediator nicotinamide adenine dinucleotide (NAD+). PGC1α did not consistently affect known autophagy pathways modulated by cisplatin. Instead RNA sequencing identified coordinated regulation of lysosomal biogenesis via TFEB. This effector pathway was sufficiently important that inhibition of TFEB or lysosomes unveiled a striking harmful effect of excess PGC1α in cells and conditional mice. These results uncover an unexpected effect of cisplatin on mitophagy and PGC1α's exquisite reliance on lysosomes for kidney protection. Finally, the data illuminate TFEB as a novel target for renal tubular stress resistance.
由于受损的线粒体可以通过氧化自由基和其他介质的产生来加速细胞死亡,因此令人惊讶的是,增殖剂γ共激活因子 1-α(PGC1α),一种增加线粒体丰度的刺激物,可保护应激状态下的肾细胞,而不是增强损伤。在这里,我们报告 PGC1α 通过转录因子 EB(TFEB)诱导溶酶体可能是肾脏保护的关键。CRISPR 和稳定基因转移表明,PGC1α 敲除肾小管细胞对基因毒性应激剂顺铂敏感,而转基因细胞则受到保护。生物传感器 mtKeima 出人意料地表明,顺铂不仅在细胞和小鼠中削弱了线粒体自噬,而且还削弱了线粒体自噬。PGC1α 不仅抵消了这种作用,还增加了基础线粒体自噬,下游介质烟酰胺腺嘌呤二核苷酸(NAD+)也是如此。PGC1α 并没有一致影响顺铂调节的已知自噬途径。相反,RNA 测序通过 TFEB 确定了溶酶体生物发生的协调调节。这种效应途径非常重要,以至于 TFEB 或溶酶体的抑制揭示了细胞和条件性小鼠中过量 PGC1α 的惊人有害作用。这些结果揭示了顺铂对线粒体自噬的意外影响以及 PGC1α 对溶酶体的肾脏保护的精细依赖。最后,这些数据阐明了 TFEB 作为肾小管应激抵抗的新靶点。