State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, 361102, People's Republic of China.
Research Institute for Biomimetics and Soft Matter, Xiamen University, Xiamen, 361005, People's Republic of China.
Arch Toxicol. 2018 Apr;92(4):1421-1434. doi: 10.1007/s00204-018-2169-0. Epub 2018 Feb 12.
Unfolded protein response (UPR) and endoplasmic reticulum (ER)-phagy are essential for cell homeostasis. Quantum dots (QDs), which have been widely used for biomedical applications, can accumulate in the kidney tissues and may cause renal dysfunction. However, the molecular mechanism of QDs-induced nephrotoxicity is still obscure. The present study was aimed to elucidate the role and mechanism of UPR and ER-phagy in QDs-induced nephrotoxicity. Herein, human embyronic kidney (HEK) cells were exposed to 15, 30, 45, and 60 nM cadmium telluride (CdTe)-QDs for 12 and 24 h. And CdTe-QDs (30-60 nM) inhibited the HEK cell viability. The clathrin-dependent endocytosis was determined as the main pathway of CdTe-QDs cellular uptake. Within cells, CdTe-QDs disrupted ER ultrastructure and induced UPR and FAM134B-dependent ER-phagy. Blocking UPR with inhibitors or siRNA rescued the FAM134B-dependent ER-phagy, which was triggered by CdTe-QDs. Moreover, suppression of UPR or FAM134B-dependent ER-phagy restored the cell vability. In vivo, mice were intravenously injected with 8 and 16 nmol/kg body weight CdTe-QDs for 24 h. Kidney was shown as one of highest distributed organs of CdTe-QDs, resulting in renal dysfunction, as well as UPR and FAM134B-dependent ER-phagy in it. Thus, for the first time, we demonstrated that ER-phagy can be triggered by nanomaterials both in vitro and in vivo. In addition, blocking of UPR and ER-phagy showed protective effects against CdTe-QDs-induced toxicity in kideny cells. Notably, a secreted alkaline phosphatase reporter gene system has been developed as a sensitive and rapid method for evaluating the ER quality under the exposure of nanomaterials.
未折叠蛋白反应（UPR）和内质网（ER）自噬对于细胞内稳态至关重要。量子点（QDs）已广泛应用于生物医学领域，但其在体内的蓄积可能导致肾功能障碍。然而，QDs 诱导肾毒性的分子机制尚不清楚。本研究旨在阐明 UPR 和 ER 自噬在 QDs 诱导的肾毒性中的作用和机制。本研究中，用人胚肾（HEK）细胞分别暴露于 15、30、45 和 60 nM 碲化镉（CdTe）-QDs 12 和 24 h。结果发现，CdTe-QDs（30-60 nM）抑制了 HEK 细胞活力。用氯丙嗪抑制网格蛋白依赖的内吞作用后，CdTe-QDs 诱导的细胞活力降低。结果表明，内吞作用是 CdTe-QDs 进入细胞的主要途径。在细胞内，CdTe-QDs 破坏内质网超微结构，并诱导 UPR 和 FAM134B 依赖性 ER 自噬。用抑制剂或 siRNA 阻断 UPR 可挽救由 CdTe-QDs 触发的 FAM134B 依赖性 ER 自噬。此外，抑制 UPR 或 FAM134B 依赖性 ER 自噬可恢复细胞活力。在体内，用 8 和 16 nmol/kg 体重的 CdTe-QDs 静脉注射小鼠 24 h，结果表明，肾脏是 CdTe-QDs 分布最高的器官之一，导致肾功能障碍以及 UPR 和 FAM134B 依赖性 ER 自噬。因此，我们首次证明了纳米材料既能在体外又能在体内诱导 ER 自噬。此外，阻断 UPR 和 ER 自噬对 CdTe-QDs 诱导的肾细胞毒性具有保护作用。值得注意的是，我们开发了一种分泌型碱性磷酸酶报告基因系统，作为一种敏感、快速的方法，用于评价纳米材料暴露下内质网的质量。
