Cao Xiaoqiong, Zhang Tong, DeLoid Glen M, Gaffrey Matthew J, Weitz Karl K, Thrall Brian D, Qian Wei-Jun, Demokritou Philip
Center for Nanotechnology and Nanotoxicology, Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA 02115, USA.
Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA.
NanoImpact. 2020 Jan;17. doi: 10.1016/j.impact.2019.100202.
Engineered nanomaterials (ENMs) are widely used in the food industry; however, regulations for ENMs in food are still in the early stages of development due to insufficient health data. This study investigated the cytotoxicity and changes to the proteomic profile in an small intestinal epithelium model after exposure to digested food models containing the ubiquitous engineered particulate food additive, TiO (E171) with an average size around 110 nm. TiO at 0.75% or 1.5% (w/w) concentrations in either a fasting food model (FFM) or a standardized food model (SFM) based on American diet were digested using an oral-gastric-small intestinal simulator, and the resulting digestas were applied to a small intestinal epithelium tri-culture cellular model. Effects on cell layer integrity, cytotoxicity, and oxidative stress were assessed. In order to explore the impact on cellular processes beyond basic cytotoxicity, mass spectrometry-based quantitative proteomic analyses of control and exposed tri-culture cells was performed. TiO in FFM, but not in SFM, produced significant, dose-dependent cytotoxicity (24%, p<0.001), and at the higher dose caused significant oxidative stress (1.24-fold, p<0.01), indicative of a food matrix effect. No significant perturbations of the cellular proteome were observed with TiO in either FFM or SFM food models. However, proteins involved in energy metabolism and protein synthesis were up-regulated by digestas from SFM compared to those from FFM, indicative of a food matrix effect on the cellular proteome. Interestingly, the differences in profiles between the two food models was more pronounced in the presence of TiO. Together, these results indicate that TiO in a fasting diet may be slightly cytotoxic, and that ingested TiO does not significantly alter the epithelial proteome, whereas the food matrix alone can have a dramatic effect on the proteome.
工程纳米材料（ENMs）在食品工业中广泛应用；然而，由于健康数据不足，食品中ENMs的相关法规仍处于发展初期。本研究调查了在暴露于含有普遍存在的工程颗粒食品添加剂二氧化钛（E171，平均粒径约110nm）的消化食品模型后，小肠上皮模型中的细胞毒性和蛋白质组学特征变化。基于美国饮食的禁食食品模型（FFM）或标准化食品模型（SFM）中，分别含有0.75%或1.5%（w/w）浓度的二氧化钛，使用口腔-胃-小肠模拟器进行消化，然后将所得消化物应用于小肠上皮三培养细胞模型。评估了对细胞层完整性、细胞毒性和氧化应激的影响。为了探究除基本细胞毒性之外对细胞过程的影响，对对照和暴露的三培养细胞进行了基于质谱的定量蛋白质组学分析。FFM中的二氧化钛产生了显著的剂量依赖性细胞毒性（24%，p<0.001），而SFM中的二氧化钛未产生，且高剂量时FFM中的二氧化钛引起了显著的氧化应激（1.24倍；p<0.01），这表明存在食物基质效应。在FFM或SFM食品模型中，二氧化钛均未观察到对细胞蛋白质组有显著干扰。然而，与FFM的消化物相比，SFM的消化物使参与能量代谢和蛋白质合成的蛋白质上调，这表明食物基质对细胞蛋白质组有影响。有趣的是，在存在二氧化钛的情况下，两种食品模型之间的特征差异更为明显。总之，这些结果表明禁食饮食中的二氧化钛可能有轻微细胞毒性，摄入的二氧化钛不会显著改变上皮蛋白质组，而仅食物基质就能对蛋白质组产生显著影响。
