Komaki Yukako, Ibuki Yuko
Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, Yada 52-1, Suruga-ku, Shizuoka 422-8526, Japan.
Toxicol In Vitro. 2025 Aug;107:106076. doi: 10.1016/j.tiv.2025.106076. Epub 2025 Apr 24.
Cigarette smoke imposes serious health hazards such as cancer and cardiovascular diseases but is also associated with cellular senescence. Recently, histone loss and modifications are reported as one of the characteristics of cellular senescence. In this study, we examined the relationship between cigarette smoke-induced cellular senescence and histone H2A variant H2AX, an important player in DNA damage response. We exposed normal human skin diploid fibroblast ASF-4-1 to cigarette sidestream smoke (CSS) extract and successfully induced premature senescence. Persistent DNA damages are known to induce cellular senescence. Double strand breaks (DSBs) formation was detected in CSS-treated cells, indicating DSBs could be the cause for the CSS-induced cellular senescence. In the senescent cells, persistent phosphorylation of histone H2AX (γ-H2AX) and unexpected increase of H2AX protein expression was observed. To elucidate the role of H2AX in CSS-induced cellular senescence, we depleted H2AX in ASF-4-1 cells with siRNA. In H2AX-depleted cells, CSS-induced elevated β-galactosidase activity was more prominent. CSS concentration-dependent increase of reactive oxygen species and DSBs formation was also facilitated by H2AX depletion. These results suggest that histone H2AX may have a protective role against DNA damage-induced premature senescence.
香烟烟雾会带来诸如癌症和心血管疾病等严重的健康危害，同时也与细胞衰老有关。最近，组蛋白缺失和修饰被报道为细胞衰老的特征之一。在本研究中，我们检测了香烟烟雾诱导的细胞衰老与组蛋白H2A变体H2AX之间的关系，H2AX是DNA损伤反应中的一个重要因子。我们将正常人皮肤二倍体成纤维细胞ASF-4-1暴露于香烟侧流烟雾（CSS）提取物中，并成功诱导了早衰。已知持续性DNA损伤会诱导细胞衰老。在CSS处理的细胞中检测到双链断裂（DSB）的形成，表明DSB可能是CSS诱导细胞衰老的原因。在衰老细胞中，观察到组蛋白H2AX（γ-H2AX）的持续磷酸化以及H2AX蛋白表达的意外增加。为了阐明H2AX在CSS诱导的细胞衰老中的作用，我们用小干扰RNA（siRNA）使ASF-4-1细胞中的H2AX缺失。在H2AX缺失的细胞中，CSS诱导的β-半乳糖苷酶活性升高更为明显。H2AX缺失还促进了CSS浓度依赖性的活性氧增加和DSB形成。这些结果表明，组蛋白H2AX可能对DNA损伤诱导的早衰具有保护作用。
