Maternal diabetes compromises the organization of hypothalamic feeding circuits and impairs leptin sensitivity in offspring

Abstract

Maternal diabetes is a common complication of pregnancy, and the offspring of diabetic mothers have a higher risk of developing obesity and type 2 diabetes later in life. Despite these observations, the precise biological processes mediating this metabolic programming are not well understood. Here, we explored the consequences of maternal diabetes on the organization of hypothalamic neural circuits involved in the regulation of energy balance. To accomplish this aim, we used a mouse model of maternal insulin deficiency induced by streptozotocin injections. Maternal diabetes was found to be associated with changes in offspring growth as revealed by a significantly higher pre- and postweaning body weight in the offspring of insulin-deficient dams relative to those of control mice. Mice born to diabetic dams also showed increased fasting glucose levels, increased insulin levels, and increased food intake during their adult lives. These impairments in metabolic regulation were associated with leptin resistance during adulthood. Importantly, the ability of leptin to activate intracellular signaling in arcuate neurons was also significantly reduced in neonates born to diabetic dams. Furthermore, neural projections from the arcuate nucleus to the paraventricular nucleus were markedly reduced in the offspring of insulin-deficient dams. Together, these data show that insulin deficiency during gestation has long-term consequences for metabolic regulation. They also indicate that animals born to diabetic dams display abnormally organized hypothalamic feeding pathways that could result from the attenuated responsiveness of hypothalamic neurons to the neurotrophic actions of leptin during neonatal development.

Fig. 1.

STZ injection during gestation induces insulin-deficient diabetes mellitus. A, Microphotographs and quantification of insulin-immunoreactive cells (brown precipitate) in the pancreatic islets of dams injected with vehicle or STZ. B, Plasma insulin levels in pregnant dams 10 d after injection of vehicle or STZ. C, Maternal blood glucose levels in dams injected with vehicle or STZ at G5.5. The values shown are means ± sem; *, P < 0.05 between vehicle and STZ (n = 4 dams per group). Scale bar, 320 μm.

Fig. 2.

Offspring born to diabetic dams display metabolic dysfunctions. A, Preweaning growth curves of pups born to control (vehicle) or diabetic (STZ) dams. B, Body weight of offspring of control (vehicle) or diabetic (STZ) dams at 63, 70, 80, and 120 d of age. C, Food intake of adult (P90) offspring born to control (vehicle) or diabetic (STZ) dams over 24 h. D, Quantification of mean adipocyte size in the epididymal WAT of adult (P120) mice born to control (vehicle) or diabetic (STZ) dams. E, Blood glucose levels in adult (P70) mice born to control (vehicle) or diabetic (STZ) dams. F, Plasma insulin levels in adult (P90) offspring of control (vehicle) and diabetic (STZ) dams. The values shown are means ± sem; *, P < 0.05 between vehicle and STZ (n = 7 males from three litters and n = 9 males from three litters for the STZ and vehicle group, respectively).

Fig. 3.

Leptin resistance in animals born to diabetic dams. A, Plasma leptin levels in adult (P90) offspring of control (vehicle) and diabetic (STZ) dams. B, Body weight changes after ip administration of leptin (Lep) or vehicle (Ctrl) in adult (P80) offspring of vehicle- or STZ-treated dams over 24 h. The values shown are mean ± sem; P < 0.05 between a and b; c and d; and e and f (n = 7 males from three litters and n = 9 males from three litters for the STZ and vehicle group, respectively).

Fig. 4.

ARH neurons exhibit a reduced response to leptin in neonates born to diabetic dams. A and B, Photomicrographs (A) and quantification (B) of the number of pSTAT3 immunoreactive cells in the arcuate nucleus (ARH) of P10 pups born to diabetic (STZ) or nondiabetic (vehicle, Veh) dams, after ip administration of leptin (Lep) or vehicle (Ctrl). The values shown are mean ± sem; P < 0.05 between * and ** (n = 4 males from three litters for each group). Scale bar, 120 μm.

Fig. 5.

Altered AgRP and αMSH neural projections in adult (P120) offspring of diabetic dams. A and B, Microphotographs and quantification of AgRP (A) and αMSH (B) immunoreactive fibers innervating the paraventricular nucleus (PVH) in adult animals born to control (vehicle, Veh) or diabetic (STZ) dams. V3, Third ventricle. The values shown are mean ± sem; *, P < 0.05 between vehicle and STZ (n = 7 males from thee litters and n = 9 males from three litters for the STZ and vehicle group, respectively). Scale bar, 130 μm.

Fig. 6.

Increased number of POMC neurons in the arcuate nucleus of animals born to diabetic dams. A and B, Microphotographs and quantification of AgRP (A) and αMSH (B) cell numbers in the arcuate nucleus (ARH) of P10 animals born to control (vehicle, Veh) or diabetic (STZ) dams. V3, Third ventricle. The values shown are mean ± sem; *, P < 0.05 between vehicle and STZ (n = 4 males from three litters for each group). Scale bar, 120 μm.