Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
Biosci Rep. 2022 Feb 25;42(2). doi: 10.1042/BSR20212433.
Acyl-CoA synthetase long-chain family member 4 (ACSL4) activates polyunsaturated fatty acids (PUFAs) to produce PUFA-derived acyl-CoAs, which are utilised for the synthesis of various biological components, including phospholipids (PLs). Although the roles of ACSL4 in non-apoptotic programmed cell death ferroptosis are well-characterised, its role in the other types of cell death is not fully understood. In the present study, we investigated the effects of ACSL4 knockdown on the levels of acyl-CoA, PL, and ferroptosis in the human normal kidney proximal tubule epithelial (HK-2) cells. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses revealed that the knockdown of ACSL4 markedly reduced the levels of PUFA-derived acyl-CoA, but not those of other acyl-CoAs. In contrast with acyl-CoA levels, the docosahexaenoic acid (DHA)-containing PL levels were preferentially decreased in the ACSL4-knockdown cells compared with the control cells. Cell death induced by the ferroptosis inducers RSL3 and FIN56 was significantly suppressed by treatment with ferrostatin-1 or ACSL4 knockdown, and, unexpectedly, upon treating with a necroptosis inhibitor. In contrast, ACSL4 knockdown failed to suppress the other oxidative stress-induced cell deaths initiated by cadmium chloride and sodium arsenite. In conclusion, ACSL4 is involved in the biosynthesis of DHA-containing PLs in HK-2 cells and is specifically involved in the cell death induced by ferroptosis inducers.
酰基辅酶 A 合成酶长链家族成员 4（ACSL4）激活多不饱和脂肪酸（PUFAs）生成 PUFA 衍生酰基辅酶 A，用于合成各种生物成分，包括磷脂（PLs）。虽然 ACSL4 在非凋亡程序性细胞死亡铁死亡中的作用已得到充分研究，但它在其他类型细胞死亡中的作用尚未完全阐明。在本研究中，我们研究了 ACSL4 敲低对人正常肾近端肾小管上皮（HK-2）细胞酰基辅酶 A、PL 和铁死亡水平的影响。液相色谱-串联质谱（LC-MS/MS）分析显示，ACSL4 敲低显著降低了 PUFA 衍生酰基辅酶 A 的水平，但不降低其他酰基辅酶 A 的水平。与酰基辅酶 A 水平相反，与对照细胞相比，ACSL4 敲低细胞中二十二碳六烯酸（DHA）含量的 PL 水平优先降低。铁死亡诱导剂 RSL3 和 FIN56 诱导的细胞死亡明显受到铁抑素-1或 ACSL4 敲低的抑制，出乎意料的是，还受到坏死性凋亡抑制剂的抑制。相比之下，ACSL4 敲低未能抑制氯化镉和亚砷酸钠引发的其他氧化应激诱导的细胞死亡。总之，ACSL4 参与 HK-2 细胞中 DHA 含量的 PL 的生物合成，并且特异性参与铁死亡诱导剂诱导的细胞死亡。
