Gong Yufeng, Yang Diwen, Liu Jiabao, Barrett Holly, Sun Jianxian, Peng Hui
Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
The Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
Environ Sci Technol. 2023 Aug 15;57(32):11913-11925. doi: 10.1021/acs.est.3c02898. Epub 2023 Aug 1.
Chemical contaminants can cause adverse effects by binding to the liver-fatty acid binding protein (L-FABP) and peroxisome proliferator-activated nuclear receptor γ (PPARγ), which are vital in lipid metabolism. However, the presence of numerous compounds in the environment has hindered the identification of their ligands, and thus only a small portion have been discovered to date. In this study, protein ffinity urification with ontargeted nalysis (APNA) was employed to identify the ligands of L-FABP and PPARγ in indoor dust and sewage sludge. A total of 83 nonredundant features were pulled-out by His-tagged L-FABP as putative ligands, among which 13 were assigned as fatty acids and hydrocarbon surfactants. In contrast, only six features were isolated when His-tagged PPARγ LBD was used as the protein bait. The binding of hydrocarbon surfactants to L-FABP and PPARγ was confirmed using both recombinant proteins and reporter cells. These hydrocarbon surfactants, along with >50 homologues and isomers, were detected in dust and sludge at high concentrations. Fatty acids and hydrocarbon surfactants explained the majority of L-FABP (57.7 ± 32.9%) and PPARγ (66.0 ± 27.1%) activities in the sludge. This study revealed hydrocarbon surfactants as the predominant synthetic ligands of L-FABP and PPARγ, highlighting the importance of re-evaluating their chemical safety.
化学污染物可通过与肝脏脂肪酸结合蛋白（L-FABP）和过氧化物酶体增殖物激活核受体γ（PPARγ）结合而产生不良影响，这两种蛋白在脂质代谢中至关重要。然而，环境中存在大量化合物，阻碍了其配体的鉴定，因此迄今为止仅发现了一小部分。在本研究中，采用蛋白质亲和纯化与非靶向分析（APNA）来鉴定室内灰尘和污水污泥中L-FABP和PPARγ的配体。用His标签的L-FABP共筛选出83个非冗余特征作为潜在配体，其中13个被鉴定为脂肪酸和烃类表面活性剂。相比之下，当使用His标签的PPARγ配体结合域作为蛋白质诱饵时，仅分离出6个特征。使用重组蛋白和报告细胞证实了烃类表面活性剂与L-FABP和PPARγ的结合。在灰尘和污泥中检测到这些烃类表面活性剂及其50多种同系物和异构体，浓度很高。脂肪酸和烃类表面活性剂解释了污泥中大部分L-FABP（57.7±32.9%）和PPARγ（66.0±27.1%）的活性。本研究揭示了烃类表面活性剂是L-FABP和PPARγ的主要合成配体，强调了重新评估其化学安全性的重要性。
