Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts.
Harvard Medical School, Boston, Massachusetts.
J Am Soc Nephrol. 2020 Sep;31(9):2097-2115. doi: 10.1681/ASN.2019020204. Epub 2020 Jul 8.
Gentamicin is a potent aminoglycoside antibiotic that targets gram-negative bacteria, but nephrotoxicity limits its clinical application. The cause of gentamicin-induced AKI has been attributed mainly to apoptosis of the proximal tubule cells. However, blocking apoptosis only partially attenuates gentamicin-induced AKI in animals.
Mice treated with gentamicin for 7 days developed AKI, and programmed cell death pathways were examined using pharmacologic inhibitors and in RIPK3-deficient mice. Effects in porcine and murine kidney cell lines were also examined.
Gentamicin caused a low level of apoptosis in the proximal tubules and significant ultrastructural alterations consistent with necroptosis, occurring predominantly in the collecting ducts (CDs), including cell and organelle swelling and rupture of the cell membrane. Upregulation of the key necroptotic signaling molecules, mixed lineage kinase domain-like pseudokinase (MLKL) and receptor-interacting serine/threonine-protein kinase 3 (RIPK3), was detected in gentamicin-treated mice and in cultured renal tubule cells. In addition, gentamicin induced apical accumulation of total and phosphorylated MLKL (pMLKL) in CDs in mouse kidney. Inhibiting a necroptotic protein, RIPK1, with necrostatin-1 (Nec-1), attenuated gentamicin-induced necrosis and upregulation of MLKL and RIPK3 in mice and cultured cells. Nec-1 also alleviated kidney inflammation and fibrosis, and significantly improved gentamicin-induced renal dysfunction in mice. Furthermore, deletion of RIPK3 in the mice significantly attenuated gentamicin-induced AKI.
A previously unrecognized role of programmed necrosis in collecting ducts in gentamicin-induced kidney injury presents a potential new therapeutic strategy to alleviate gentamicin-induced AKI through inhibiting necroptosis.
庆大霉素是一种有效的氨基糖苷类抗生素，针对革兰氏阴性菌，但肾毒性限制了其临床应用。庆大霉素诱导的急性肾损伤的原因主要归因于近端肾小管细胞的凋亡。然而，在动物中，阻断凋亡只能部分减轻庆大霉素诱导的 AKI。
用庆大霉素处理 7 天的小鼠发生 AKI，并使用药理抑制剂和 RIPK3 缺陷小鼠检查程序性细胞死亡途径。还检查了猪和鼠肾细胞系的作用。
庆大霉素在近端小管中引起低水平的凋亡，并伴有与坏死性凋亡一致的显著超微结构改变，主要发生在集合管（CDs）中，包括细胞和细胞器肿胀以及细胞膜破裂。在庆大霉素处理的小鼠和培养的肾小管细胞中检测到关键坏死性信号分子混合谱系激酶结构域样伪激酶（MLKL）和受体相互作用丝氨酸/苏氨酸蛋白激酶 3（RIPK3）的上调。此外，庆大霉素诱导小鼠肾脏 CD 中总和磷酸化 MLKL（pMLKL）的顶端积累。用坏死抑制剂 1（Nec-1）抑制坏死性蛋白 RIPK1，可减轻小鼠和培养细胞中庆大霉素诱导的坏死和 MLKL 和 RIPK3 的上调。Nec-1 还减轻了肾脏炎症和纤维化，并显著改善了小鼠庆大霉素诱导的肾功能障碍。此外，在 RIPK3 缺陷小鼠中删除 RIPK3 可显著减轻庆大霉素诱导的 AKI。
程序性坏死在庆大霉素诱导的肾损伤中的集合管中的一个以前未被认识的作用提出了一种通过抑制坏死性凋亡减轻庆大霉素诱导的 AKI 的潜在新治疗策略。
