High-fat diet affects pregestational adiposity and glucose tolerance perturbing gestational placental macronutrient transporters culminating in an obese offspring in wild-type and glucose transporter isoform 3 heterozygous null mice

We examined the effect of a high-fat diet (HFD) vs. control diet (CD) upon pregestational and gestational wild-type (wt) and glucose transporter (glut)3 heterozygous (glut3+/−) female mice and observed an increase in pregestational body weights, white adiposity (wt > glut3+/−), circulating cholesterol, and high-density lipoproteins, with glucose intolerance in both genotypes. The HFD-exposed offspring displayed reduced birth weight with catch up to CD-fed in wt vs. an increased birth weight persisting as such at weaning by day 21 in glut3+/− mice. To decipher the mechanism behind this genotype-specific difference in the HFD offspring's phenotype, we first examined placental macronutrient transporters and noted HFD-induced increase in CD36 in wt with no change in other FATPs, sodium-coupled neutral amino acid transporters and system L amino acid transporter in both genotypes. In contrast, while placental Glut1 increased in both the genotypes, only Glut3 increased in the glut3+/− genotype in response to HFD. Hence, we next assessed glut3+/− embryonic (ES) cells under differing stressors of low glucose, hypoxia and inhibition of oxidative phosphorylation. Reduced Glut3-mediated glucose uptake in glut3+/− vs. wt ES cells culminated in deficient growth. We conclude that maternal HFD affects the in utero growth potential of the offspring by altering placental CD36 and Glut1 concentrations. In contrast, a differential effect on placental Glut3 concentrations between glut3+/− and wt genotypes is evident, with an increase occurring in the glut3+/− genotype alone. Deficient Glut3 in ES cells interferes with glucose uptake, cell survival and growth being further exaggerated with low glucose, hypoxia and inhibition of oxidative phosphorylation.