Supplementary Material for: The Hippo Coactivator TAZ exacerbates cisplatin-induced acute renal injury

Introduction: Transcriptional coactivator with PDZ-binding motif (TAZ), a Hippo signaling pathway effector, maintains the balance of cell proliferation, differentiation, and death. However, the role of TAZ in tubular cell survival and acute kidney injury (AKI) remains largely unknown.
Methods: We used RNA-seq database, western blot and immune-histochemistry to examine TAZ expression in kidneys from cisplatin-induced AKI. We generated tubular-specific TAZ knockout mice to assess the role of TAZ in cisplatin-induced renal toxicity. Immunoprecipitation-mass spectrometry followed standard procedures.
Results: TAZ was activated in tubular cells in kidneys injected with cisplatin. Conditional deletion of TAZ in tubule cells confers ferroptosis resistance and protects kidneys from cisplatin-induced AKI, whereas overexpression of TAZ(S89A) exacerbates cisplatin-induced ferroptosis. Inhibition of ferroptosis with ferrostatin-1 potently preserves renal function and alleviates morphological injury and tubular cell ferroptosis induced by cisplatin. Mechanistically, in a PPARδ-dependent manner, but not TEAD, TAZ reduces the expression of glutathione peroxidase 4 (GPX4), thus, exacerbating cisplatin-induced ferroptosis.
Conclusions: Our findings show that cisplatin-induced AKI and tubular cell ferroptosis is mediated by TAZ-PPARδ interaction through regulation of GPX4, highlighting TAZ as a potential therapeutic candidate for AKI.

引言：含PDZ结合基序的转录共激活因子（TAZ）作为Hippo信号通路效应分子，可维持细胞增殖、分化与死亡的动态平衡。然而，TAZ在肾小管细胞存活及急性肾损伤（AKI）中的作用仍不甚明确。
方法：本研究借助RNA测序（RNA-seq）数据库、蛋白质印迹（western blot）及免疫组织化学（immune-histochemistry）技术，检测顺铂诱导的急性肾损伤（cisplatin-induced AKI）小鼠肾脏中TAZ的表达水平；构建肾小管特异性TAZ敲除小鼠，以评估TAZ在顺铂诱导的肾毒性中的作用；免疫沉淀-质谱联用（immunoprecipitation-mass spectrometry）实验严格遵循标准操作流程。
结果：顺铂处理后，肾脏肾小管细胞中的TAZ被激活。肾小管细胞条件性敲除TAZ可产生铁死亡（ferroptosis）抵抗，保护肾脏免受顺铂诱导的急性肾损伤；而过表达TAZ(S89A)则会加重顺铂诱导的铁死亡。使用铁抑素-1（ferrostatin-1）可有效维持肾功能，缓解顺铂诱导的肾脏形态损伤及肾小管细胞铁死亡。机制上，TAZ通过依赖过氧化物酶体增殖物激活受体δ（PPARδ）而非TEAD的方式，下调谷胱甘肽过氧化物酶4（GPX4）的表达，进而加重顺铂诱导的铁死亡。
结论：本研究结果表明，顺铂诱导的急性肾损伤及肾小管细胞铁死亡是通过TAZ-PPARδ相互作用调控GPX4所介导的，这一发现提示TAZ可作为急性肾损伤的潜在治疗候选靶点。