Intrauterine programming mechanism for hypercholesterolemia in prenatal caffeine‐exposed female adult rat offspring

Abstract

Clinical and animal studies have indicated that hypercholesterolemia and its associated diseases have intrauterine developmental origins. Our previous studies showed that prenatal caffeine exposure (PCE) led to fetal overexposure to maternal glucocorticoids (GCs) and increased serum total cholesterol levels in adult rat offspring. This study further confirms the intrauterine programming of PCE-induced hypercholesterolemia in female adult rat offspring. Pregnant Wistar rats were intragastrically administered caffeine (30, 60, and 120 mg/kg/d) from gestational day (GD)9 to 20. Female rat offspring were euthanized at GD20 and postnatal wk 12; several adult rat offspring were additionally subjected to ice-water swimming stimulation to induce chronic stress prior to death. The effects of GCs on cholesterol metabolism and epigenetic regulation were verified using the L02 cell line. The results showed that PCE induced hypercholesterolemia in adult offspring, which manifested as significantly higher levels of serum total cholesterol and LDL cholesterol (LDL-C) as well as higher ratios of LDL-C/HDL cholesterol. We further found that the cholesterol levels were increased in fetal livers but were decreased in fetal blood, accompanied by increased maternal blood cholesterol levels and reduced placental cholesterol transport. Furthermore, analysis of PCE offspring in the uterus and in a postnatal basal/chronic stress state and the results of in vitro experiments showed that hepatic cholesterol metabolism underwent GC-dependent changes and was associated with cholesterol synthase via abnormalities in 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) histone acetylation. We concluded that, to compensate for intrauterine placentally derived decreases in fetal blood cholesterol levels, high intrauterine GC levels activated fetal hepatic CCAAT enhancer binding protein α signaling and down-regulated Sirtuin1 expression, which mediated the high levels of histone acetylation ( via H3K9ac and H3K14ac) and expression of HMGCR. This GC-dependent cholesterol metabolism programming effect was sustained through adulthood, leading to the occurrence of hypercholesterolemia.-Xu, D., Luo, H. W., Hu, W., Hu, S. W., Yuan, C., Wang, G. H., Zhang, L., Yu, H., Magdalou, J., Chen, L. B., Wang, H. Intrauterine programming mechanism for hypercholesterolemia in prenatal caffeine-exposed female adult rat offspring.

Epigenetic Regulation of Key Enzymes CYP7a1 and HMGCR Affect Hepatic Cholesterol Metabolism in Different Breeds of Piglets

“…Based on our and other precious studies, liver modulates cholesterol transport, biosynthesis and transformation in pigs predominantly via epigenetic regulation (20,21). We chose CYP7a1 and HMGCR for epigenetic because the promoter sequences of these two genes can be used in pigs and both of them are key enzymes in the cholesterol metabolism (20,29,30). CpG island cytosine methylation located in promoter genes is associated with gene suppression (31,32), while histone acetylation is related to the activation of transcription (20,29,30).…”

“…We chose CYP7a1 and HMGCR for epigenetic because the promoter sequences of these two genes can be used in pigs and both of them are key enzymes in the cholesterol metabolism (20,29,30). CpG island cytosine methylation located in promoter genes is associated with gene suppression (31,32), while histone acetylation is related to the activation of transcription (20,29,30). According to the type of histone, the position of amino acid residues and the number of methyl groups (mono-, di-and trimethylation), histone methylation can inhibit or activate gene transcription.…”

“…Extract total and nuclear proteins from 100 mg of frozen liver tissue, as previously described (30). Detection of protein concentration with Pierce BCA Protein Assay Kit (Thermo Scientific, USA).…”

Impacts of Caffeine during Pregnancy

“…Mechanistically, the adverse effects of caffeine on F1 offspring could be due to early embryo caffeine exposure via oviductal or uterine fluid [15], or during later exposure that bypasses the blood-placenta barrier. In addition to the direct effect of caffeine exposure, recent studies also found that caffeine intake during mid-to-late pregnancy can cause an increase in maternal glucocorticoids [56]; fetus exposed to such an environment can result in long-term programming of fetal hypothalamic-pituitary-adrenal axis [57], which could disrupt neuroendocrine metabolism and increase susceptibility to metabolism syndrome, such as hypercholesterolemia, in adult offspring [56,58] (Figure 3).…”

The low‐expression programming of 11β‐HSD2 mediates osteoporosis susceptibility induced by prenatal caffeine exposure in male offspring rats

“…Whereas, caffeine exposure during pregnancy can do a variety of short‐term and long‐term harm to offspring. In our previous studies, we found that prenatal caffeine exposure caused developmental toxicities of multiple organs in fetal offspring and susceptibility to several kinds of diseases in adulthood (He et al, 2019; Shangguan et al, 2017; Tan et al, 2012; Xu et al, 2018). However, the effects of prenatal caffeine exposure on peak bone mass accumulation and osteoporosis susceptibility in offspring and the underlying mechanism have not been fully clarified.…”