Potentiation of Adipogenesis by Reactive Oxygen Species is a Unifying Mechanism in the Pro-adipogenic Properties of Bisphenol A and its New Structural Analogues

Aims Structural analogues of bisphenol A (BPA), including BPS and BPF, are emerging environmental toxicants as their presence in the environment is rising since new regulatory restrictions were placed on BPA-containing infant products. The adipogenesis-enhancing effect of bisphenols may explain the link between human exposure and metabolic disease; Methods Adipose-derived progenitors were isolated from mice and exposed to various concentrations of BPS, BPA or BPF before induction of adipogenesis. RNAseq in BPS-exposed progenitors revealed modulation in redox pathways. The role of reactive oxygen species (ROS) was assessed by measuring the degree of adipogenesis in the presence or absence of antioxidants. ROS production and mitochondria function were determined by fluorescent assays. Fat mass was measured by TD-NMR in adult mice exposed to BPS during in utero establishment of the adipocyte progenitor pool, and in adult mice exposed to BPS after weaning. however, underlying molecular pathways remain unresolved. Results Exposure of progenitors to BPS, BPF, BPA or ROS generators enhanced lipid droplet formation and expression of adipogenic markers after induction of differentiation. ROS was higher in bisphenol-exposed cells, while co-treatment with antioxidants attenuated adipogenesis and abolished the effect of BPS. There was a loss of mitochondria membrane potential in BPS-exposed cells and mitochondria-derived ROS contributed to potentiation of adipogenesis by BPS and its analogues. Male mice exposed to BPS during gestation had higher adiposity, while postnatal exposure had no impact on adiposity in either sex. ROS act as signaling molecules in the regulation of adipocyte differentiation and mediate bisphenol-induced potentiation of adipogenesis. Overall design: Comparative gene expression profiling analysis of RNA seq data for preadipocyte cells derived from wild-type murine inguinal subcutaneous adipose tissue, which were then exposed to vehicle or 2.5uM BPS.

研究目的：双酚A（bisphenol A, BPA）的结构类似物（包括双酚S（BPS）与双酚F（BPF））现已成为新兴环境污染物。由于针对含BPA的婴幼儿产品出台了新的监管限制，这类物质在环境中的检出量持续上升。双酚类物质的促脂肪生成效应，或可解释人类暴露于该类物质与代谢疾病之间的潜在关联。
研究方法：从小鼠体内分离脂肪源性祖细胞，在诱导脂肪生成前，采用不同浓度的BPS、BPA或BPF对细胞进行暴露处理。对BPS暴露的祖细胞进行RNA测序（RNA-seq）分析，结果显示氧化还原通路存在显著调控变化。通过在添加或不添加抗氧化剂的条件下检测脂肪生成程度，评估活性氧（reactive oxygen species, ROS）的具体作用。采用荧光分析法检测ROS生成水平与线粒体功能。采用时域核磁共振（TD-NMR）检测两类成年小鼠的体脂含量：一类是在脂肪细胞祖细胞库建立的宫内暴露阶段接触BPS的小鼠，另一类是断奶后暴露于BPS的小鼠。目前该过程的潜在分子通路仍未明确。
研究结果：祖细胞经BPS、BPF、BPA或ROS诱导剂暴露后，在诱导分化过程中可显著增强脂滴形成与脂肪生成标志物的表达。双酚类物质暴露的细胞内ROS水平升高，而与抗氧化剂联合处理可减弱脂肪生成过程，并完全消除BPS的上述效应。BPS暴露的细胞出现线粒体膜电位丧失，且线粒体来源的ROS可增强BPS及其类似物的促脂肪生成作用。妊娠期暴露于BPS的雄性小鼠体脂含量更高，而断奶后暴露则对雌雄小鼠的体脂均无显著影响。ROS可作为信号分子调控脂肪细胞分化，并介导双酚类物质诱导的促脂肪生成效应。
整体实验设计：对源自野生型小鼠腹股沟皮下脂肪组织的前脂肪细胞进行比较基因表达谱分析，实验分为溶剂对照处理组与2.5μM BPS暴露组，对两组的RNA-seq数据开展分析。