Glucocorticoid programming mechanism for hypercholesterolemia in prenatal ethanol-exposed adult offspring rats.

Abstract

Our previous studies showed that prenatal ethanol exposure (PEE) elevated blood total cholesterol (TCH) level in adult offspring rats. This study was aimed at elucidating the intrauterine programming mechanism of hypercholesterolemia in adult rats induced by PEE. Pregnant Wistar rats were intragastrically administered ethanol (4\u202fmg/kg∙d) from gestational day (GD) 9 to 20. The offspring rats were euthanized at GD20 and postnatal week 24. Results showed that PEE decreased serum TCH and HDL-C levels (female and male) as well as LDL-C level (female only) in fetal rats but increased serum TCH level and the TCH/HDL-C and LDL-C/HDL-C ratios in adult rats. Furthermore, PEE elevated serum corticosterone levels but inhibited hepatic insulin-like growth factor 1 (IGF1) signaling pathway, cholesterol synthesis and output in fetal rats. The conversed changes were observed in adult rats. Moreover, histone acetylation (H3K9ac and H3K14ac) and expression of hepatic reverse cholesterol transport (RCT) related genes, scavenger receptor BI and low-density lipoprotein receptor were decreased before and after birth by PEE. In HepG2 cells, cortisol negatively regulated the IGF1 signaling pathway and cholesterol metabolic genes, but this inhibition of the cholesterol metabolic genes could be reversed by glucocorticoid receptor antagonist RU486, whereas exogenous IGF1 treatment only reversed the downregulation of RCT genes by cortisol. We confirmed a two programming mechanism for PEE-induced hypercholesterolemia in adult rats. The first programming was a glucocorticoid (GC)-induced persistent reduction of RCT genes by epigenetic modifications, and the second programming was the negative regulation of cholesterol synthesis and output by the GC-IGF1 axis.