Changes in cellular cholesterol metabolism are associated with fetal programming of atherosclerosis

Abstract

WITH FETAL PROGRAMMING OF ATHEROSCLEROSIS NIMA GOHARKHAY, KARINA VILLARREAL, SERGIO RODRIGUEZ, AMANDA MARETH, KENDRA STISSER, ESTHER TAMAYO, PHYLLIS GAMBLE, MICHEL MAKHLOUF, GARLAND D. ANDERSON, MONICA LONGO, GEORGE SAADE, University of Texas Medical Branch, Obstetrics & Gynecology/Maternal Fetal Medicine, Galveston, Texas, University of Texas Medical Branch, Obstetrics & Gynecology/ Gynecologic Oncology, Galveston, Texas OBJECTIVE: We previously described a model of fetal programming of atherosclerosis in the offspring of hypercholesterolemic ApoE knockout mice. The objective of this study was to determine the mechanisms affected by inutero programming, focusing on transcriptional control, synthesis and cellular uptake of cholesterol in the liver. STUDY DESIGN: ApoE knockout (KO) and wild-type (WT) mice were crossbred to obtain 4 groups of offspring: KO, WT, heterozygous born to ApoE deficient mothers (KOMat) and heterozygous born to WT mothers (KOPat). All animals were sacrificed at eight months of age. Real-time RT-PCR was performed to detect mRNA expression levels for the LDL receptor (LDLR), HMG-CoA synthase, liver X receptor (LXR), SREBP cleavage activator protein (SCAP), peroxisome proliferator-activator receptor (PPAR)-gamma and PPAR-delta in the liver. LDLR protein levels were determined by Western blot. RESULTS: SCAP levels were significantly elevated in KOMat offspring as compared to both KOPat and WT animals (p=0.03). HMG-CoA synthase expression was also higher in the KOMat versus the other groups. In KOMat animals HMG-CoA synthase and SCAP mRNA levels were highly correlated (p!0.0001, r=0.81). PPAR-g and PPAR-d levels were somewhat higher in KOMat mice, while LXR and LDLR expression did not vary significantly. No substantial gender differences were noted. CONCLUSION: Elevated SCAP levels stimulate HMG-CoA synthase expression in the liver of offspring born to hypercholesterolemic mothers compared with genomically similar offspring born to normal mothers. This may underlie the mechanism by which in-utero exposure to high cholesterol levels alters fetal programming of cholesterol synthesis.