Pogribna Marta, Word Beverly, Lyn-Cook Beverly, Hammons George
Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food & Drug Administration, Jefferson, AR, USA.
Nanotoxicology. 2022 May;16(4):409-424. doi: 10.1080/17435390.2022.2085206. Epub 2022 Jul 24.
Titanium dioxide (TiO) nanoparticles are widely manufactured, with a range of applications in consumer products. Significant toxicity of TiO nanoparticles has, however, been recognized, suggesting considerable risk to human health. To evaluate fully their toxicity, assessment of the epigenetic action of these nanoparticles is critical. However, only few studies are available examining the capability of nanoparticles to alter epigenetic integrity. In the present study, the effect of TiO nanoparticles exposure on histone modifications, a major epigenetic mechanism, was investigated in human colorectal (Caco-2) and lung (NL20) epithelial cell lines. Histone H3 and H4 modifications were assessed by array analysis using the EpiQuick Histone H3 or H4 Modification Multiplex Assay. Seventeen histone modifications were identified with altered levels after exposure to TiO nanoparticles. Changes in several selected histone modifications (Caco-2 cells: H3cit, H3K9me3, H3K27me3, H3K36me3, H3K9ac, and H4K8ac; NL20 cells: H3K4me3, H3K9me3, H3K27me3, H3K9ac, and H3K18ac) were verified by Western blot analysis. The results also revealed aberrant expression of histone modifying enzymes in TiO exposed cells. Expression levels were determined by array analysis using the Human Epigenetic Chromatin Modification Enzymes RT Profiler™ PCR Array, with 12 genes identified in both Caco-2 cells and NL20 cells. qRT-PCR analysis confirmed the array results for several selected histone modifying enzyme genes ( and ). The findings from this study clearly demonstrate the impact of TiO nanoparticles exposure on histone modification in two human cell lines, supporting potential involvement of this epigenetic mechanism in the toxicity of TiO nanoparticles. Hence, for complete assessment of potential risk from nanoparticle exposure, epigenetic studies are critical.
二氧化钛（TiO）纳米颗粒被广泛生产，在消费品中有一系列应用。然而，人们已经认识到TiO纳米颗粒具有显著毒性，这表明对人类健康存在相当大的风险。为了全面评估其毒性，对这些纳米颗粒的表观遗传作用进行评估至关重要。然而，只有少数研究考察了纳米颗粒改变表观遗传完整性的能力。在本研究中，在人结肠（Caco-2）和肺（NL20）上皮细胞系中研究了TiO纳米颗粒暴露对主要表观遗传机制——组蛋白修饰的影响。使用EpiQuick组蛋白H3或H4修饰多重检测试剂盒通过阵列分析评估组蛋白H3和H4修饰。在暴露于TiO纳米颗粒后，鉴定出17种组蛋白修饰水平发生改变。通过蛋白质印迹分析验证了几种选定组蛋白修饰（Caco-2细胞：H3cit、H3K9me3、H3K27me3、H3K36me3、H3K9ac和H4K8ac；NL20细胞：H3K4me3、H3K9me3、H3K27me3、H3K9ac和H3K18ac）的变化。结果还揭示了TiO暴露细胞中组蛋白修饰酶的异常表达。使用人类表观遗传染色质修饰酶RT Profiler™ PCR阵列通过阵列分析确定表达水平，在Caco-2细胞和NL20细胞中均鉴定出12个基因。qRT-PCR分析证实了几种选定组蛋白修饰酶基因的阵列结果（和）。本研究结果清楚地证明了TiO纳米颗粒暴露对两个人类细胞系中组蛋白修饰的影响，支持这种表观遗传机制可能参与TiO纳米颗粒的毒性作用。因此，对于全面评估纳米颗粒暴露的潜在风险，表观遗传学研究至关重要。
