Department of Biology and Biotechnology 'L. Spallanzani', University of Pavia, 27100, Pavia, Italy.
Department of Biology and Biosciences, University of Milano-Bicocca, 20126, Milan, Italy.
Histochem Cell Biol. 2023 Jan;159(1):61-76. doi: 10.1007/s00418-022-02151-8. Epub 2022 Sep 22.
Mercury is a highly toxic element that induces severe alterations and a broad range of adverse effects on health. Its exposure is a global concern because it is widespread in the environment due to its multiple industrial, domestic, agricultural and medical usages. Among its various chemical forms, both humans and animals are mainly exposed to mercury chloride (HgCl), methylmercury and elemental mercury. HgCl is metabolized primarily in the liver. We analysed the effects on the nuclear architecture of an increasing dosage of HgCl in mouse hepatocytes cell culture and in mouse liver, focusing specifically on the organization, on some epigenetic features of the heterochromatin domains and on the nucleolar morphology and activity. Through the combination of molecular and imaging approaches both at optical and electron microscopy, we show that mercury chloride induces modifications of the heterochromatin domains and a decrease of some histones post-translational modifications associated to heterochromatin. This is accompanied by an increase in nucleolar activity which is reflected by bigger nucleoli. We hypothesized that heterochromatin decondensation and nucleolar activation following mercury chloride exposure could be functional to express proteins necessary to counteract the harmful stimulus and reach a new equilibrium.
汞是一种剧毒元素，会对健康造成严重的损害和广泛的不良影响。由于其在工业、家庭、农业和医疗方面的多种用途，汞的暴露是一个全球性的问题。在其各种化学形式中，人类和动物主要接触的是氯化汞（HgCl）、甲基汞和元素汞。HgCl 主要在肝脏中代谢。我们分析了在小鼠肝细胞培养物和小鼠肝脏中，HgCl 剂量增加对核结构的影响，特别关注异染色质区域的组织、一些表观遗传特征以及核仁形态和活性。通过在光学和电子显微镜下结合分子和成像方法，我们表明氯化汞会诱导异染色质区域的改变，并降低与异染色质相关的一些组蛋白的翻译后修饰。这伴随着核仁活性的增加，表现为核仁变大。我们假设，氯化汞暴露后异染色质解凝聚和核仁激活可能是表达必要蛋白以对抗有害刺激并达到新的平衡的功能。
