磷酸三苯酯暴露经PPAR介导的脂类代谢干扰作用

Metabolic diseases such as overweight and obesity have become ubiquitous disease in China. Some environmental pollutants exert as obesogens in disturbing the lipid metabolism through peroxisome proliferation activation receptors (PPARs). We have observed significant up-regulation of PPARα and PPARγ in hepatocytes under the tri-phenyl phosphate (TPhP) exposure, which further elevated the expressions of genes from lipid metabolism pathway. Therefore, this study attempts to unravel the specific role of TPhP on lipid metabolism disruption through PPAR regulation in hepatocytes. PPAR specific agonist, antagonist and siRNA are employed to explore the regulation of TPhP on PPARs by determining the mRNA/protein levels of PPARs and lipid metabolism genes. In addition, the metabolisms of TPhP and lipid profiles are measured by LC-MS to demonstrate the effect of TPhP on lipid metabolism which would be further examined by animal study. The study aims to develop biomarker of TPhP toxicity by verifying PPAR as the critical target of TPhP and demonstrating the disturbance of TPhP on PPAR and lipid metabolism.

超重、肥胖等代谢疾病已成为中国乃至全球范围的流行性疾病，部分环境污染物可作为肥胖因子干扰过氧化物酶增殖激活剂受体（PPAR）功能，并影响脂类代谢与积累。申报人前期研究表明，在磷酸三苯酯（TPhP）暴露下，人肝细胞PPARα和PPARγ表达显著上调，并影响脂类代谢相关通路的基因表达。由此提出假设，肝细胞的PPAR能受TPhP特异性诱导，并介导脂类代谢等干扰过程，影响脂类积累并导致动物肥胖。本项目拟采用PPAR特异性激活剂、抑制剂及SiRNA等处理手段验证TPhP对PPAR的干扰作用，测定关键基因/蛋白表达水平，以LC-MS分析其对TPhP代谢产物与脂类组成的影响，阐明TPhP对肝细胞PPAR干扰的特异性及调控过程，并通过动物试验进一步验证。本项目对于明确PPAR作为TPhP暴露关键靶点，阐明TPhP对肝细胞PPAR及其脂类代谢调控的作用，筛选TPhP毒性生物标记提供科学依据。

阻燃剂是被广泛应用于电子产品与家电中的一类添加剂，并且在使用过程中释放后广泛存在于水体、空气与室内灰尘等环境介质中。本项目通过磷酸三苯酯（Tri phenyl phosphate，TPhP）探讨了磷系阻燃剂在人肝细胞中的代谢模式，并比较了TPhP和过氧化物酶体增殖剂激活受体（peroxisome proliferators-activated receptors，PPARs）激活剂/拮抗剂对PPARs及其下游基因表达的调控作用，发现TPhP对L02和HepG2的PPARs均有上调作用，并且存在剂量效应；通过磷酸三(1,3-二氯异丙基)酯（Tris1,3-dichloro-2-propyl phosphate，TDCIPP）对C57BL/6 小鼠长期暴露，发现磷系阻燃剂主要存在于肌肉和毛发组织，而肝脏、肾脏组织则以其代谢产物为主，并且TDCIPP暴露对肠道微生物的糖代谢与多糖生物合成通道存在干扰作用；此外，项目还对溴环十二烷（hexabromocyclododecanes，HBCDs) 在人体内的立体异构体和对映异构体选择性富集进行探讨，发现三种HBCD立体异构体的清除率（γ-HBCDs > β-HBCDs > α-HBCDs ）与过去报道中HBCDs生物富集异构体选择特征一致，并且HBCDs在肝脏代谢、转运与富集具有对映体选择性。