Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, China.
School of Pharmaceutical Sciences and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, China.
J Endocrinol. 2019 Jul 26;242(3):211-226. doi: 10.1530/JOE-19-0066.
We previously showed that prenatal caffeine exposure (PCE) induces intrauterine growth retardation (IUGR) and high susceptibility to nonalcoholic fatty liver disease in offspring rats, and the underlying mechanisms are associated with fetal overexposure to maternal glucocorticoids. Herein, we aimed to verify whether PCE disrupts liver development before and after birth and explore its possible programming mechanism. In vivo, reduced fetal weights and increased IUGR rates were accompanied by fetal liver developmental dysfunction in PCE rats. Increased fetal serum corticosterone and decreased insulin-like growth factor 1 (IGF1) levels were observed. Both male and female fetal livers exhibited increased glucocorticoid function-related gene (GR/C/EBPα) expression and inhibited IGF1 signaling pathway (IGF1/IGF1R/Akt2) expression. At PW6, the levels of serum corticosterone and glucocorticoid function-related genes in PCE offspring livers were decreased, while serum IGF1 and liver IGF1 signaling pathway expression were increased, accompanied by obvious catch-up growth and enhanced liver function. Furthermore, in PCE adult offspring under chronic stress, serum corticosterone and liver GR/C/EBPα expression levels were elevated, while the serum IGF1 and liver IGF1 signaling pathway levels were decreased. In vitro, cortisol (not caffeine) upregulated GR and C/EBPα expression and downregulated IGF1R expression. The IGF1R expression downregulated by cortisol was partially reversed by GR or C/EBPα knockdown. In conclusion, PCE induced liver developmental dysfunction in fetal rats and catch-up growth in IUGR offspring. The mechanisms may be closely associated with GR/C/EBPα upregulation and IGF1/IGF1R signaling pathway downregulation in the fetal liver, caused by intrauterine programming of the liver glucocorticoid-IGF1 axis induced by glucocorticoid overexposure.
我们之前的研究表明,产前咖啡因暴露(PCE)会导致宫内胎儿生长迟缓(IUGR)和后代大鼠非酒精性脂肪肝(NAFLD)的易感性增加,其潜在机制与胎儿过度暴露于母体糖皮质激素有关。在此,我们旨在验证 PCE 是否会破坏出生前后的肝脏发育,并探索其可能的编程机制。在体内,PCE 大鼠的胎儿体重减轻和 IUGR 发生率增加伴随着胎儿肝脏发育功能障碍。观察到胎儿血清皮质酮增加和胰岛素样生长因子 1(IGF1)水平降低。雄性和雌性胎儿肝脏均表现出糖皮质激素功能相关基因(GR/C/EBPα)表达增加和 IGF1 信号通路(IGF1/IGF1R/Akt2)表达受抑制。在 PW6 时,PCE 后代肝脏中的血清皮质酮和糖皮质激素功能相关基因水平降低,而血清 IGF1 和肝脏 IGF1 信号通路表达增加,伴随着明显的追赶生长和增强的肝功能。此外,在慢性应激下,PCE 成年后代的血清皮质酮和肝脏 GR/C/EBPα 表达水平升高,而血清 IGF1 和肝脏 IGF1 信号通路水平降低。在体外,皮质醇(而非咖啡因)上调了 GR 和 C/EBPα 的表达,并下调了 IGF1R 的表达。皮质醇下调的 IGF1R 表达部分被 GR 或 C/EBPα 敲低所逆转。总之,PCE 导致胎儿大鼠肝脏发育功能障碍和 IUGR 后代的追赶生长。其机制可能与宫内编程导致的肝脏糖皮质激素-IGF1 轴中肝糖皮质激素-IGF1 轴过度暴露引起的胎儿肝脏中 GR/C/EBPα 上调和 IGF1/IGF1R 信号通路下调密切相关。