Sexual dimorphism in offspring glucose-sensitive hypothalamic gene expression and physiological responses to maternal high-fat diet feeding

Abstract

A wealth of animal and human studies demonstrate that early life environment significantly influences adult metabolic balance, however the etiology for offspring metabolic misprogramming remains incompletely understood. Here, we determine the effect of maternal diet per se on offspring sex-specific outcomes in metabolic health and hypothalamic transcriptome regulation in mice. Furthermore, to define developmental periods of maternal diet misprogramming aspects of offspring metabolic balance, we investigated offspring physiological and transcriptomic consequences of maternal high-fat/high-sugar diet feeding during pregnancy and/or lactation. We demonstrate that female offspring of high-fat/high-sugar diet-fed dams are particularly vulnerable to metabolic perturbation with body weight increases due to postnatal processes, whereas in utero effects of the diet ultimately lead to glucose homeostasis dysregulation. Furthermore, glucose- and maternal-diet sensitive gene expression modulation in the paraventricular hypothalamus is strikingly sexually dimorphic. In summary, we uncover female-specific, maternal diet-mediated in utero misprogramming of offspring glucose homeostasis and a striking sexual dimorphism in glucose- and maternal diet-sensitive paraventricular hypothalamus gene expression adjustment. Notably, female offspring metabolic vulnerability to maternal high-fat/high-sugar diet propagates a vicious cycle of obesity and type 2 diabetes in subsequent generations.

Figure 1.

Glucose-sensitive hypothalamic gene expression modulation. A, PVH. B, ARC Glut3, Irs2, Crh, and Kir6.2 mRNA expression (TaqMan probe and multiplexing against 18S rRNA) was measured in male CD1 mice 60 minutes after either a saline injection (sal) or insulin-induced hypoglycemia (<2.5 mM blood glucose; hypo) (n = 5–9; *, P < .05; **, P < .01; ***, P < .001 t-test for individual genes).

Figure 2.

Mouse model of maternal dietary programming. A, Lean CD1 dams are fed either chow or a high-fat diet (HFD, 58% fat + high sucrose) during pregnancy and lactation only. All offspring is weaned onto chow and offspring from chow-fed dams (offC) compared with offspring from HFD-fed dams (offHFD) at P4, P21/weaning and at 8 weeks. B, Body weight and C, Blood glucose of chow- and HFD-fed dams during pregnancy and lactation (n = 8; **, P < .01; *, P < .05, 2-way repeated measures ANOVA). D, Dam adiposity was measured as %fat by DXA scanning a day after birth and at weaning (n = 4–5). E, Dam serum insulin was measured one day after birth and at weaning (n = 4–5).

Figure 3.

Female offspring of HFD-fed dams are more vulnerable to increased weight. A, Body weight and blood glucose of (unsexed) P4 offspring from chow-fed (offC) or HFD-fed (offHFD) dams (n = 15). B, Female and male offC and offHFD body weight and blood glucose at P21/weaning (n = 33–42; **, P < .01; ***, P < .001; 1-way ANOVA). C, Female body weight and blood glucose curves after weaning until 8 weeks of age. D, Male body weight and blood glucose curves after weaning until 8 weeks of age (n = 14–24; **, P < .01; *, P < .05; 2-way repeated measures ANOVA).

Figure 4.

Adult female offspring of HFD-fed dams have dysfunctional glucose homeostasis. A, 8-week-old female and male offspring adiposity was measured as %fat by DXA scanning (n = 18–26; *, P < .05; t-test). B, Serum insulin levels of fed 8-week-old female and male offC and offHFD (n = 6–9). C, 8-week-old female and male offC and offHFD were fasted at 9:00 AM for 6 hours and blood glucose measured at 1 and 6 hours (n = 13–15; *, P < .05; 2-way repeated measures ANOVA). D, Glucose tolerance test (2g/kg) in 8-week-old female and male offC and offHFD (n = 8–11; **, P < .01; 2-way repeated measures ANOVA). Adjacent area under curve analysis (n = 8–11; *, P < .05; t test).

Figure 5.

Sexual dimorphism in PVH glucose- and maternal-diet-sensitive gene expression regulation. cDNA was generated from microdissected PVH in 8-week-old A, female and B, male offC and offHFD mice 60 minutes after either a saline (sal) or 2.5U/kg insulin (hypo) injection and expression of Irs2, Glut3, Kir6.2, and Crh measured using TaqMan probes by multiplexing against 18S rRNA (n = 6–11; **, P < .01; *, P < .05; 1-way ANOVA for individual genes)

Figure 6.

Absence of glucose:PVH gene expression correlation in female mice. Kir6.2 (top panels) and Irs2 mRNA (bottom panels) expression at different glycemic states in adult female (left panels) and male (right panels), normo-, hyper-, and hypoglycemic offC mice. Gene expression values derive from different experiments and are normalized to each experimental average (arb units).

Figure 7.

Glucose homeostasis dysregulation in female offspring of HFD-fed dams is programmed in utero. A, Lean CD1 dams (n = 6–8) are fed: chow during pregnancy and lactation (offspring is offC/C), HFD during pregnancy only (offspring is offHFD/C), HFD during lactation only (offspring is offC/HFD), or HFD during pregnancy and lactation (offspring is offHFD/HFD). All offspring is weaned onto chow. B, Offspring body weight (n = 18–26; ***, P < .001; **, P < .01; *, P < .05; 2-way repeated measures ANOVA). C, 8-week-old female offC/C, offHFD/C, offC/HFD, and offHFD/HFD were fasted at 9:00 AM for 6 hours. Blood glucose drop is expressed as %prefast (n = 10–14; **, P < .01; *, P < .05; 2-way repeated measures ANOVA).