Cocci Paolo, Mosconi Gilberto, Arukwe Augustine, Mozzicafreddo Matteo, Angeletti Mauro, Aretusi Graziano, Palermo Francesco Alessandro
†School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III Da Varano, I-62032 Camerino (MC), Italy.
‡Department of Biology, Norwegian University of Science and Technology (NTNU), Høgskoleringen 5, 7491 Trondheim, Norway.
Chem Res Toxicol. 2015 May 18;28(5):935-47. doi: 10.1021/tx500529x. Epub 2015 Apr 15.
Evidence that endocrine-disrupting chemicals (EDCs) may target metabolic disturbances, beyond interference with the functions of the endocrine systems has recently accumulated. Among EDCs, phthalate plasticizers like the diisodecyl phthalate (DiDP) are commonly found contaminants of aquatic environments and have been suggested to function as obesogens by activating peroxisome proliferator activated receptors (PPARs), a subset of nuclear receptors (NRs) that act as metabolic sensors, playing pivotal roles in lipid homeostasis. However, little is known about the modulation of PPAR signaling pathways by DiDP in fish. In this study, we have first investigated the ligand binding efficiency of DiDP to the ligand binding domains of PPARs and retinoid-X-receptor-α (RXRα) proteins in fish using a molecular docking approach. Furthermore, in silico predictions were integrated by in vitro experiments to show possible dose-relationship effects of DiDP on PPAR:RXR-dependent gene expression pathways using sea bream hepatocytes. We observed that DiDP shows high binding efficiency with piscine PPARs demonstrating a greater preference for RXRα. Our studies also demonstrated the coordinate increased expression of PPARs and RXRα, as well as their downstream target genes in vitro. Principal component analysis (PCA) showed the strength of relationship between transcription of most genes involved in fatty acid metabolism and PPAR mRNA levels. In particular, fatty acid binding protein (FABP) was highly correlated to all PPARs. The results of this study suggest that DiDP can be considered an environmental stressor that activates PPAR:RXR signaling to promote long-term changes in lipid homeostasis leading to potential deleterious physiological consequences in teleost fish.
内分泌干扰化学物质（EDCs）可能针对代谢紊乱，而不仅仅是干扰内分泌系统功能的证据最近有所积累。在EDCs中，邻苯二甲酸酯类增塑剂，如邻苯二甲酸二异癸酯（DiDP），是水环境中常见的污染物，有人认为它通过激活过氧化物酶体增殖物激活受体（PPARs）发挥致肥胖作用，PPARs是核受体（NRs）的一个子集，作为代谢传感器，在脂质稳态中起关键作用。然而，关于DiDP对鱼类PPAR信号通路的调节作用知之甚少。在本研究中，我们首先使用分子对接方法研究了DiDP与鱼类PPARs和视黄酸X受体α（RXRα）蛋白的配体结合域的配体结合效率。此外，通过体外实验整合了计算机模拟预测，以显示DiDP对使用鲷鱼肝细胞的PPAR:RXR依赖性基因表达途径可能的剂量关系效应。我们观察到DiDP与鱼类PPARs具有高结合效率，对RXRα表现出更大的偏好。我们的研究还证明了体外PPARs和RXRα及其下游靶基因的协同表达增加。主成分分析（PCA）显示了参与脂肪酸代谢的大多数基因的转录与PPAR mRNA水平之间的关系强度。特别是，脂肪酸结合蛋白（FABP）与所有PPARs高度相关。本研究结果表明，DiDP可被视为一种环境应激源，它激活PPAR:RXR信号，促进脂质稳态的长期变化，从而导致硬骨鱼潜在的有害生理后果。
