摘要:
超过3 000种全氟多氟化合物(per- and polyfluoroalkyl substances, PFASs)已被投入全球市场，大量新型替代品的环境效应与健康风险仍然未知，为PFASs的监管带来了极大的挑战。为揭示PFASs及新型替代品干扰的生物学过程和敏感靶基因，将人骨髓间充质干细胞(human bone mesenchymal stem cells, hBMSCs)暴露于氯代多氟醚基磺酸(chlorinated polyfluoroalkyl ether sulfonates, Cl-PFESAs)、全氟辛烷磺酸(perfluorooctane sulfonate, PFOS)、全氟己烷磺酸(perfluorohexane sulfonate, PFHxS)和全氟辛酸(perfluorooctanoic acid, PFOA)，利用加权基因共表达网络分析(weighted gene co-expression network analysis, WGCNA)方法比较细胞基因表达谱的变化。WGCNA使用拓扑重叠计算5 004个基因间的关联程度，并结合动态剪切树法将其划分为14个通过颜色区分的基因模块，除灰色模块外各模块内的基因高度相关。基因模块与细胞样本相关性分析发现，对照组细胞基因表达谱与Blue和Greenyellow模块正相关，PFOS暴露组与Blue模块显著负相关，Cl-PFESAs暴露组与Greenyellow模块显著负相关，表明PFASs暴露使细胞中Blue和Greenyellow模块基因表达模式发生较大变化。Blue和Greenyellow模块显著富集的生物学过程主要为胆固醇生物合成和骨髓白细胞分化负调控，提示免疫调控和脂质代谢可能是多种PFASs作用于hBMSCs的共同潜在靶点。根据模块基因共表达网络的连通性筛选枢纽基因，发现与脂质代谢相关的DHCR24、SQLE和EBP基因可能是PFASs影响脂质代谢的敏感作用靶基因。进一步利用hBMSCs体外模型研究PFASs的相关毒性作用和机制，有助于建立该类化学物毒性预测和筛选的生物标志物，为其安全性评价和监管提供科学依据和新方法。
Abstract:
More than 3 000 kinds of per- and polyfluoroalkyl substances (PFASs) are in use globally, for which the environmental effects and health risks are not well-known, challenging the regulation of PFASs broadly as a chemical class. Aiming to unravel the sensitive toxicity targets of perfluoroalkyl compounds and the emerging substituted compounds, human bone mesenchymal stem cells (hBMSCs) were employed as an in vitro model. The gene profiles affected by chlorinated polyfluoroalkyl ether sulfonates (Cl-PFESAs), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and perfluorooctanoic acid (PFOA) were analysed by weighted gene co-expression network analysis (WGCNA). The association among 5 004 genes was analysed by topological overlap in WGCNA, and 14 gene modules named by different color were identified by dynamic tree cut. Except grey module, the genes in each module are highly correlated. Correlation analysis between the modules and cell samples indicated that control cells were positively correlated with Blue and Greenyellow modules, while PFOS and Cl-PFESAs exposure were negatively correlated with Blue module and Greenyellow module, respectively, indicating that PFASs exposure induced relatively remarkable changes in the gene expression patterns of Blue and Greenyellow modules. The most significantly enriched biological processes in Blue and Greenyellow modules were cholesterol biosynthetic process and negative regulation of myeloid leukocyte differentiation, respectively, implying that immunoregulation and lipid metabolism were the potential targets of PFASs. The pivotal genes were screened by the connectivity of the modular gene co-expression network, which revealed that DHCR24, SQLE and EBP, i.e., key genes involved in lipid metabolism, might be target genes of PFASs. The results of the present study suggested that hBMSCs provide an in vitro model to further study the toxic effects and mechanisms of PFASs, which would contribute to the development of biomarkers for toxicity prediction and screening of PFASs, as well as to provide experimental evidence and novel method for the health risk assessment and regulation.
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