Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, United States.
Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, United States.
Chem Res Toxicol. 2021 May 17;34(5):1265-1274. doi: 10.1021/acs.chemrestox.0c00386. Epub 2021 Jan 20.
We previously found that the widely used disinfectants, benzalkonium chlorides (BACs), alter cholesterol and lipid homeostasis in neuronal cell lines and in neonatal mouse brains. Here, we investigate the effects of BACs on neurospheres, an three-dimensional model of neurodevelopment. Neurospheres cultured from mouse embryonic neural progenitor cells (NPCs) were exposed to increasing concentrations (from 1 to 100 nM) of a short-chain BAC (BAC C12), a long-chain BAC (BAC C16), and AY9944 (a known DHCR7 inhibitor). We found that the sizes of neurospheres were decreased by both BACs but not by AY9944. Furthermore, we observed potent inhibition of cholesterol biosynthesis at the step of DHCR7 by BAC C12 but not by BAC C16, suggesting that cholesterol biosynthesis inhibition is not responsible for the observed reduction in neurosphere growth. By using immunostaining and cell cycle analysis, we found that both BACs induced apoptosis and decreased proliferation of NPCs. To explore the mechanisms underlying their effect on neurosphere growth, we carried out RNA sequencing on neurospheres exposed to each BAC at 50 nM for 24 h, which revealed the activation of the integrated stress response by both BACs. Overall, these results suggest that BACs affect neurodevelopment by inducing the integrated stress response in a manner independent of their effects on cholesterol biosynthesis.
我们之前发现，广泛使用的消毒剂苯扎氯铵（BACs）会改变神经元细胞系和新生小鼠大脑中的胆固醇和脂质稳态。在这里，我们研究了 BACs 对神经球的影响，神经球是神经发育的三维模型。从小鼠胚胎神经祖细胞（NPCs）培养的神经球暴露于浓度逐渐增加（从 1 到 100 nM）的短链 BAC（BAC C12）、长链 BAC（BAC C16）和 AY9944（一种已知的 DHCR7 抑制剂）。我们发现，两种 BAC 都能减小神经球的大小，但 AY9944 则不能。此外，我们观察到 BAC C12 强烈抑制了 DHCR7 步骤的胆固醇生物合成，但 BAC C16 则没有，这表明胆固醇生物合成抑制不是观察到的神经球生长减少的原因。通过免疫染色和细胞周期分析，我们发现两种 BAC 均诱导 NPC 凋亡和增殖减少。为了探索它们对神经球生长影响的机制，我们对暴露于 50 nM 每种 BAC 24 小时的神经球进行了 RNA 测序，结果表明两种 BAC 均激活了整合应激反应。总的来说，这些结果表明，BACs 通过诱导与胆固醇生物合成无关的整合应激反应来影响神经发育。
