Kanno S, Hirano S, Monma-Otaki J, Kato H, Fukuta M, Takase H, Nakamura Y, Oshima T
Department of Forensic Medicine, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan.
Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan.
Arch Toxicol. 2025 Apr 9. doi: 10.1007/s00204-025-04026-y.
Acute exposure to high concentrations of hydrogen sulfide (HS), a toxic gaseous substance, can cause potentially lethal respiratory damages. Stress granules (SGs) are cytoprotective membrane-less intracellular organelles formed transiently in response to various stressors. We examined SG formation and the underlying molecular mechanism following exposure to high concentrations of HS using human bronchial BEAS-2B (BEAS) and GFP-tagged G3BP1-stably transfected CHO cells. We first examined the changes in intracellular HS concentration by NaHS exposure. Qualitative and quantitative analyses revealed that intracellular HS levels rapidly increased after NaHS exposure and accumulated in cells dose dependently. In terms of the response to HS taken up after exposure to 2.5-10 mM NaHS, both cell lines formed discrete SG assemblies within 1 h. SG formation induced by NaHS exposure was enhanced by treatment with glutathione (GSH) or thioredoxin (Trx) inhibitor but suppressed by treatment with a PERK inhibitor or integrated stress response inhibitor. Levels of phosphorylation of eIF2 α, which is essential for canonical SG formation, were significantly and dose-dependently increased in NaHS-exposed BEAS cells. Phosphorylation of eIF2α was further increased by GSH or Trx inhibitor treatment. These results suggest that GSH and Trx play protective roles in HS-induced SG formation. PERK, a kinase of eIF2α, might activate the pathway partially. Levels of newly synthesized proteins were markedly reduced in NaHS-exposed cells. In summary, when humans inhale high concentrations of HS, HS is rapidly taken up by pulmonary cells and induces SG formation and translational repression via eIF2α phosphorylation, thereby protecting against cell death.
急性暴露于高浓度的硫化氢（HS）这种有毒气体物质中，可能会导致潜在致命的呼吸道损伤。应激颗粒（SGs）是细胞保护性的无膜细胞器，在应对各种应激源时会短暂形成。我们使用人支气管BEAS-2B（BEAS）细胞和绿色荧光蛋白标记的G3BP1稳定转染的CHO细胞，研究了暴露于高浓度HS后应激颗粒的形成及其潜在的分子机制。我们首先通过硫氢化钠（NaHS）暴露来检测细胞内HS浓度的变化。定性和定量分析表明，NaHS暴露后细胞内HS水平迅速升高，并呈剂量依赖性在细胞中积累。就暴露于2.5-10 mM NaHS后摄取的HS的反应而言，两种细胞系在1小时内都形成了离散的应激颗粒聚集体。用谷胱甘肽（GSH）或硫氧还蛋白（Trx）抑制剂处理可增强NaHS暴露诱导的应激颗粒形成，但用PERK抑制剂或综合应激反应抑制剂处理则会抑制这种形成。真核生物翻译起始因子2α（eIF2α）的磷酸化水平对于经典应激颗粒的形成至关重要，在暴露于NaHS的BEAS细胞中显著且呈剂量依赖性增加。用GSH或Trx抑制剂处理可进一步增加eIF2α的磷酸化。这些结果表明，GSH和Trx在HS诱导的应激颗粒形成中起保护作用。eIF2α的激酶PERK可能部分激活该途径。在暴露于NaHS的细胞中，新合成蛋白质的水平明显降低。总之，当人类吸入高浓度HS时，HS会迅速被肺细胞摄取，并通过eIF2α磷酸化诱导应激颗粒形成和翻译抑制，从而防止细胞死亡。
