Department of Developmental and Cell Biology, University of California, Irvine, CA 92697-2300, USA.
Medical Scientist Training Program, University of California, Irvine, CA 92697-2300, USA.
Endocrinology. 2023 Mar 13;164(5). doi: 10.1210/endocr/bqad027.
Exposure of pregnant F0 mouse dams to the obesogen tributyltin (TBT) predisposes unexposed male descendants to obesity and diverts mesenchymal stem cells (MSCs) toward the adipocytic lineage. TBT promotes adipogenic commitment and differentiation of MSCs in vitro. To identify TBT-induced factors predisposing MSCs toward the adipocytic fate, we exposed mouse MSCs to TBT, the peroxisome proliferator activated receptor gamma (PPARγ)-selective agonist rosiglitazone, or the retinoid X receptor (RXR)-selective agonist LG-100268. Then we determined their transcriptomal profiles to determine candidate microRNAs (miR) regulating adipogenic commitment and differentiation. Of the top 10 candidate microRNAs predicted by Ingenuity Pathway Analysis, miR-21, miR-33, and miR-223 were expressed consistent with an ability to differentially regulate target genes during adipogenesis. We found that 24-hour exposure to 50nM TBT caused miR-223 levels in MSCs to increase; expression of its target genes ZEB1, NFIB, and FOXP1 was decreased. Rosiglitazone and TBT increased miR-223 levels. This induction was inhibited by the PPARγ antagonist T0070907 but not by the RXR antagonists HX531 or UVI3003, placing miR-223 downstream of PPARγ. Chromatin immunoprecipitation confirmed TBT-induced binding of PPARγ to regulatory elements in the miR-223 promoter. miR-223 levels were elevated in white adipose tissue of F2 and F3 male descendants of pregnant F0 mouse dams exposed to 50nM TBT throughout gestation. miR-223 levels were potentiated in males fed an increased fat diet. We infer that TBT induced miR-223 expression and increased adipogenesis in MSCs through the PPARγ pathway and that transgenerationally increased expression of miR-223 plays an important role in the development of obesity caused by TBT exposure.
孕期 F0 雌鼠接触肥胖物三丁基锡（TBT）会使未暴露的雄性后代易肥胖，并使间充质干细胞（MSCs）向脂肪细胞谱系分化。TBT 可促进 MSC 在体外的成脂性定向和分化。为了鉴定 TBT 诱导的使 MSCs 向脂肪细胞命运发展的因素，我们将小鼠 MSCs 暴露于 TBT、过氧化物酶体增殖物激活受体γ（PPARγ）选择性激动剂罗格列酮或视黄酸 X 受体（RXR）选择性激动剂 LG-100268 中。然后，我们确定了它们的转录组谱，以确定调节成脂性定向和分化的候选 microRNA（miR）。通过 Ingenuity 通路分析预测的前 10 个候选 microRNA 中，miR-21、miR-33 和 miR-223 的表达与在脂肪生成过程中差异调节靶基因的能力一致。我们发现，50nM TBT 暴露 24 小时会导致 MSCs 中 miR-223 水平增加；其靶基因 ZEB1、NFIB 和 FOXP1 的表达减少。罗格列酮和 TBT 增加了 miR-223 水平。这种诱导作用被 PPARγ 拮抗剂 T0070907 抑制，但不受 RXR 拮抗剂 HX531 或 UVI3003 的抑制，这表明 miR-223 位于 PPARγ 下游。染色质免疫沉淀证实 TBT 诱导了 PPARγ 与 miR-223 启动子调节元件的结合。在整个孕期接触 50nM TBT 的孕期 F0 雌鼠的 F2 和 F3 雄性后代的白色脂肪组织中，miR-223 水平升高。在喂食高脂肪饮食的雄性中，miR-223 水平升高。我们推断，TBT 通过 PPARγ 途径诱导 MSCs 中 miR-223 的表达和增加脂肪生成，并且跨代增加的 miR-223 表达在 TBT 暴露引起的肥胖发展中起着重要作用。
