Abstract：
Nanoparticles, particularly magnesium oxide nanoparticles (MgO-NPs), are increasingly utilized in various fields, yet their potential impact on cellular systems remains a topic of concern. This study aimed to comprehensively investigate the molecular mechanisms underlying MgO-NP-induced cellular impairment in Saccharomyces cerevisiae, with a focus on cell wall integrity, endoplasmic reticulum (ER) stress response, mitochondrial function, lipid metabolism, autophagy, and epigenetic alterations. MgO-NPs were synthesized through a chemical reduction method, characterized for morphology, size distribution, and elemental composition. Concentration-dependent toxicity assays were conducted to evaluate the inhibitory effect on yeast growth, accompanied by propidium iodide (PI) staining to assess membrane damage. Intracellular reactive oxygen species (ROS) accumulation was measured, and chitin synthesis, indicative of cell wall perturbation, was examined along with the expression of chitin synthesis genes. Mitochondrial function was assessed through Psd1 localization, and ER structure was analyzed using dsRed-HDEL marker. The unfolded protein response (UPR) pathway activation was monitored, and lipid droplet formation and autophagy induction were investigated. Results demonstrated a dose-dependent inhibition of yeast growth by MgO-NPs, with concomitant membrane damage and ROS accumulation. Cell wall perturbation was evidenced by increased chitin synthesis and upregulation of chitin synthesis genes. MgO-NPs impaired mitochondrial function, disrupted ER structure, and activated the UPR pathway. Lipid droplet formation and autophagy were induced, indicating cellular stress responses. Additionally, MgO-NPs exhibited differential cytotoxicity on histone mutant strains, implicating specific histone residues in cellular response to nanoparticle stress. Immunoblotting revealed alterations in histone posttranslational modifications, particularly enhanced methylation of H3K4me. This study provides comprehensive insights into the multifaceted effects of MgO-NPs on S. cerevisiae, elucidating key molecular pathways involved in nanoparticle-induced cellular impairment. Understanding these mechanisms is crucial for assessing nanoparticle toxicity and developing strategies for safer nanoparticle applications.
摘要：
纳米颗粒,特别是氧化镁纳米颗粒（MgO-NP），越来越多地应用于各个领域，然而，它们对蜂窝系统的潜在影响仍然是一个值得关注的话题。本研究旨在全面探讨MgO-NP诱导酿酒酵母细胞损伤的分子机制。关注细胞壁的完整性，内质网（ER）应激反应，线粒体功能，脂质代谢，自噬,和表观遗传改变。MgO-NP是通过化学还原法合成的，以形态为特征，大小分布，和元素组成。进行浓度依赖性毒性试验以评估对酵母生长的抑制作用，伴随碘化丙啶（PI）染色以评估膜损伤。测量细胞内活性氧（ROS）积累，和几丁质合成，指示细胞壁扰动，与几丁质合成基因的表达一起检查。线粒体功能通过Psd1定位进行评估，并使用dsRed-HDEL标记分析ER结构。监测未折叠蛋白反应（UPR）途径的激活，并研究了脂滴形成和自噬诱导。结果表明MgO-NP对酵母生长的剂量依赖性抑制，伴随膜损伤和ROS积累。几丁质合成增加和几丁质合成基因上调证明了细胞壁扰动。MgO-NP受损线粒体功能，中断的ER结构，并激活了UPR通路。诱导脂滴形成和自噬，表明细胞应激反应。此外,MgO-NP对组蛋白突变菌株表现出不同的细胞毒性，特定组蛋白残基参与细胞对纳米颗粒胁迫的反应。免疫印迹揭示了组蛋白翻译后修饰的变化，特别是H3K4me的甲基化增强。这项研究为MgO-NP对酿酒酵母的多方面影响提供了全面的见解，阐明参与纳米颗粒诱导的细胞损伤的关键分子途径。了解这些机制对于评估纳米颗粒毒性和开发更安全的纳米颗粒应用策略至关重要。
