Loss of ERα partially reverses the effects of maternal high-fat diet on energy homeostasis in female mice

Abstract

Maternal high-fat diet (HFD) alters hypothalamic developmental programming and disrupts offspring energy homeostasis in rodents. 17β-estradiol (E2) also influences hypothalamic programming through estrogen receptor (ER) α. Therefore, we hypothesized that females lacking ERα would be more susceptible to maternal HFD. To address this question, heterozygous ERα knockout (WT/KO) dams were fed a control breeder chow diet (25% fat) or a semi-purified HFD (45% fat) 4 weeks prior to mating with WT/KO males or heterozygous males with an ERα DNA-binding domain mutation knocked in (WT/KI) to produce WT, ERα KO, or ERα KIKO females lacking ERE-dependent ERα signaling. Maternal HFD increased body weight in WT and KIKO, in part, due to increased adiposity and daytime carbohydrate utilization in WT and KIKO, while increasing nighttime fat utilization in KO. Maternal HFD also increased plasma leptin, IL-6, and MCP-1 in WT and increased arcuate expression of Kiss1 and Esr1 (ERα) and liver expression of G6pc and Pepck in WT and KIKO. Contrary to our hypothesis, these data suggest that loss of ERα signaling blocks the influence of maternal HFD on energy homeostasis, inflammation, and hypothalamic and liver gene expression and that restoration of ERE-independent ERα signaling partially reestablishes susceptibility to maternal HFD.

Figure 1

Body weight and body composition of adult females. (a) Body weights at week 5 in all genotypes from Control-fed and HFD-fed dams. (b) Body weights at week 25 in all genotypes after 20 weeks of a low-fat chow diet. (c) Percent body fat (fat mass/body mass) of female mice from all groups. (d) Percent lean mass (lean mass/body mass) of female mice from all groups. Control = maternal control diet and HFD = maternal HFD. Data were analyzed by two-way ANOVA with post-hoc Newman-Keuls test. Sample sizes were 9 to 12 per genotype per treatment and data are expressed as mean ± SEM. Capped lines denote comparison between maternal diets within genotypes. Asterisks (*) denote comparison to WT within the same diet group. The pound sign (#) denotes comparison of KIKO and KO within the diet group. (a/*/# = P < 0.05; b/**/## = P < 0.01; c/***/### = P < 0.001; d/****/#### = P < 0.0001).

Figure 2

Metabolic and activity parameters in females from all genotypes after 20 weeks of adult chow diet determined using the CLAMS. (a) V.O₂ (ml/min/kg); (b) V.CO₂ (ml/min/kg); (c) Respiratory exchange ratio (RER) (V.CO₂ /V.O₂); (d) Energy expenditure (kCal/hr/lean mass (g)); (e) X-plane activity (counts); and (f) Z-plane activity (counts). Data were analyzed by a multi-factorial ANOVA (genotype, maternal diet, time) with post-hoc Newman-Keuls test. See Fig. 1 for information on treatment categories, sample sizes, and statistical comparisons (a/*/# = P < 0.05; b/**/## = P < 0.01; c/***/### = P < 0.001; d/****/#### = P < 0.0001).

Figure 3

Fasting glucose levels and glucose tolerance test (GTT) in adult females from all genotypes after 20 weeks of adult chow diet. (a) Fasting glucose levels. Results from the GTT from (b) all genotypes from Control-fed dams and (c) all genotypes from HFD-fed dams. (d) Area under the curve (AUC) analysis for all genotypes from both maternal diets. (a and d) Data were analyzed by a two-way ANOVA with post-hoc Newman-Keuls test. (b and c) Data were analyzed by repeated-measures, multi-factorial ANOVA with post-hoc Newman-Keuls test. See Fig. 1 for information on treatment categories, sample sizes, and statistical comparisons (a/*/# = P < 0.05; b/**/## = P < 0.01; c/***/### = P < 0.001; d/****/#### = P < 0.0001).

Figure 4

Insulin tolerance test (ITT) in adult females from all genotypes after 20 weeks of adult chow diet. Results from the ITT from (a) all genotypes from Control-fed dams and (b) all genotypes from HFD-fed dams. (c) AUC analysis for all genotypes from both maternal diets. (a and b) Data were analyzed by repeated-measures, multi-factorial ANOVA with post-hoc Newman-Keuls test. (c) Data were analyzed by a two-way ANOVA with post-hoc Newman-Keuls test. See Fig. 1 for information on treatment categories, sample sizes, and statistical comparisons (a/*/# = P < 0.05; b/**/## = P < 0.01; c/***/### = P < 0.001; d/****/#### = P < 0.0001).

Figure 5

Peripheral peptide hormones and inflammatory cytokines from all genotypes after 20 weeks of adult chow diet. (a) Plasma levels of 17β-estradiol (pg/ml). (b) Plasma levels of insulin (ng/ml). (c) Plasma levels of leptin (ng/ml). (d) Plasma levels of IL-6 (pg/ml). (e) Plasma levels of MCP-1 (pg/ml). (f) Plasma levels of TNFα (pg/ml). Data were analyzed by a two-way ANOVA with post-hoc Newman-Keuls test. See Fig. 1 for information on treatment categories, sample sizes, and statistical comparisons (a/*/# = P < 0.05; b/**/## = P < 0.01; c/***/### = P < 0.001; d/****/#### = P < 0.0001).

Figure 6

Arcuate gene expression in all genotypes after 20 weeks of adult chow diet. (a) Pomc; (b) Cart; (c) Npy; (d) Agrp; (e) Kiss1; and (f) Esr1 (ERα) expression normalized to WT from Control-fed dams. Data were analyzed by a two-way ANOVA with post-hoc Newman-Keuls test within each genotype. See Fig. 1 for information on treatment categories, sample sizes, and statistical comparisons (a/*/# = P < 0.05; b/**/## = P < 0.01; c/***/### = P < 0.001; d/****/#### = P < 0.0001).

Figure 7

Liver gene expression in all genotypes after 20 weeks of adult chow diet. (a) G6pc; (b) Pepck; (c) Dgat2; (d) Fas; (e) Srebp1; and (f) Esr1 (ERα) expression normalized to WT from Control-fed dams. Data were analyzed by a two-way ANOVA with post-hoc Newman-Keuls test within each genotype. See Fig. 1 for information on treatment categories, sample sizes, and statistical comparisons (a/*/# = P < 0.05; b/**/## = P < 0.01; c/***/### = P < 0.001; d/****/#### = P < 0.0001).