Titanium dioxide (TiO₂) particles are a common ingredient in food, providing the bright white color for many candies, gums, and frostings. While ingestion of these materials has been examined previously, few studies have examined the effect of these particles on lung cells. Inhalation is an important exposure pathway for workers processing these foods and, more recently, home users who purchase these particles directly. We examine the response of lung cells to food-grade TiO₂ particles using a combination of fluorescence microscopy and RT-PCR. These experiments show that TiO₂ particles generate intracellular reactive oxygen species, specifically superoxide, and alter expression of two epigenetic modifiers, histone deacetylase 9 (HDAC9) and HDAC10. We use a protein corona formed from superoxide dismutase (SOD), an enzyme that scavenges superoxide, to probe the relationship between TiO₂ particles and superoxide generation. These experiments show that low, non-cytotoxic, concentrations of food-grade TiO₂ particles lead to cellular responses, including altering two enzymes responsible for epigenetic modifications. This production of superoxide and change in epigenetic modifiers could affect human health following inhalation. We expect this research will motivate future in vivo experiments examining the pulmonary response to food-grade TiO₂ particles.

中文翻译：

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食品级二氧化钛颗粒在人肺细胞中产生细胞内超氧化物并改变表观遗传修饰物

二氧化钛 (TiO ₂ ) 颗粒是食品中的常见成分，为许多糖果、口香糖和糖霜提供亮白色。虽然之前已经检查了这些材料的摄入，但很少有研究检查这些颗粒对肺细胞的影响。吸入是加工这些食品的工人以及最近直接购买这些颗粒的家庭用户的重要接触途径。我们使用荧光显微镜和 RT-PCR 的组合检查肺细胞对食品级 TiO ₂颗粒的反应。这些实验表明 TiO ₂粒子产生细胞内活性氧物质，特别是超氧化物，并改变两种表观遗传修饰剂的表达，组蛋白脱乙酰酶 9 (HDAC9) 和 HDAC10。我们使用由超氧化物歧化酶 (SOD)（一种清除超氧化物的酶）形成的蛋白质电晕来探测 TiO ₂颗粒与超氧化物生成之间的关系。这些实验表明，低浓度、无细胞毒性的食品级 TiO ₂颗粒会导致细胞反应，包括改变负责表观遗传修饰的两种酶。这种超氧化物的产生和表观遗传修饰剂的变化可能会影响吸入后的人类健康。我们预计这项研究将推动未来的体内实验，检查肺部对食品级 TiO _{2 的反应} 粒子。