Neonatal ghrelin programs development of hypothalamic feeding circuits
Sophie M. Steculorum, … , Sven Klussmann, Sebastien G. Bouret
Sophie M. Steculorum, … , Sven Klussmann, Sebastien G. Bouret
Published January 20, 2015
Citation Information: J Clin Invest. 2015;125(2):846-858. https://doi.org/10.1172/JCI73688.
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Research Article

Neonatal ghrelin programs development of hypothalamic feeding circuits

Abstract

A complex neural network regulates body weight and energy balance, and dysfunction in the communication between the gut and this neural network is associated with metabolic diseases, such as obesity. The stomach-derived hormone ghrelin stimulates appetite through interactions with neurons in the arcuate nucleus of the hypothalamus (ARH). Here, we evaluated the physiological and neurobiological contribution of ghrelin during development by specifically blocking ghrelin action during early postnatal development in mice. Ghrelin blockade in neonatal mice resulted in enhanced ARH neural projections and long-term metabolic effects, including increased body weight, visceral fat, and blood glucose levels and decreased leptin sensitivity. In addition, chronic administration of ghrelin during postnatal life impaired the normal development of ARH projections and caused metabolic dysfunction. Consistent with these observations, direct exposure of postnatal ARH neuronal explants to ghrelin blunted axonal growth and blocked the neurotrophic effect of the adipocyte-derived hormone leptin. Moreover, chronic ghrelin exposure in neonatal mice also attenuated leptin-induced STAT3 signaling in ARH neurons. Collectively, these data reveal that ghrelin plays an inhibitory role in the development of hypothalamic neural circuits and suggest that proper expression of ghrelin during neonatal life is pivotal for lifelong metabolic regulation.

Authors

Sophie M. Steculorum, Gustav Collden, Berengere Coupe, Sophie Croizier, Sarah Lockie, Zane B. Andrews, Florian Jarosch, Sven Klussmann, Sebastien G. Bouret

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Figure 5

Ghrelin blocks axonal growth from neonatal ARH neurons.

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Ghrelin blocks axonal growth from neonatal ARH neurons. (A) Quantificati...
(A) Quantification and photomicrographs of βIII-tubulin–immunopositive fibers, a marker of neurites, from isolated organotypic cultures of neonatal ARH incubated for 48 hours with vehicle or ghrelin (100 ng/ml) (n = 6 cases per group). (B) Quantification of βIII-tubulin–immunopositive fibers from isolated cultures of neonatal ARH incubated for 48 hours with vehicle, ghrelin, or ghrelin and NOX-B11-2 (n = 8 for ghrelin, and ghrelin + NOX-B11-2; n = 11 for vehicle). (C) Photomicrographs and quantification of the number of leptin-induced pSTAT3-IR cells in the ARH of P10 pups injected with ghrelin (2 mg/kg) or vehicle from P4 to P10 (n = 4 for vehicle; n = 6 for PN ghrelin). (D) Images and quantification of the overall density of βIII-tubulin–immunopositive fibers from isolated organotypic cultures of neonatal ARH incubated for 48 hours with vehicle, leptin (100 ng/ml), or leptin + ghrelin (n = 9 for leptin; n = 15 for leptin + ghrelin; n = 19 for vehicle). (E) Circulating acylated ghrelin level of P10 WT and leptin-deficient (ob/ob) mice (n = 9 for WT; n = 12 for ob/ob). (F) Relative expression of Ghsr mRNA in the hypothalamus of P12 WT and ob/ob mice (n = 6 per group). (G and H) Confocal images and quantification of AgRP-IR fibers (G) and α-MSH-IR fibers (H) in the PVH of P12 ob/ob mice neonatally injected with the control or anti-ghrelin compound (n = 4 per group). Values are shown as the mean ± SEM. V3, third ventricle. *P < 0.05 vs. vehicle; #P < 0.05 vs. leptin. Statistical significance was determined using 2-tailed Student’s t tests (C and E–H) and a 2-way ANOVA followed by Bonferroni’s post-hoc test (A, B, and D). Scale bars: 100 μm (A and D); 150 μm (C, G, and H).