Astrocytes Modulate Distribution and Neuronal Signaling of Leptin in the Hypothalamus of Obese A ^sup vy^ Mice

• Published in: Journal of molecular neuroscience Vol. 43; no. 3; p. 478
• Main Authors: Pan, Weihong, Hsuchou, Hung, Xu, Changlei, Wu, Xiaojun, Bouret, Sebastien G, Kastin, Abba J
• Format: Journal Article
• Language: English
• Published: Totowa Springer Nature B.V 01.03.2011
• Subjects: Hypothalamus; Hypotheses; Laboratories; Metabolism; Neurons; Obesity; United States > US
• ISSN: 0895-8696; 1559-1166
• DOI: 10.1007/s12031-010-9470-6

We tested the hypothesis that astrocytic activity modulates neuronal uptake and signaling of leptin in the adult-onset obese agouti viable yellow (A ^sup vy^) mouse. In the immunohistochemical study, A ^sup vy^ mice were pretreated with the astrocyte metabolic inhibitor fluorocitrate or phosphate-buffered saline (PBS) vehicle intracerebroventricularly (icv) followed 1 h later by Alexa568-leptin. Confocal microscopy showed that fluorocitrate pretreatment reduced astrocytic uptake of Alexa568-leptin 30 min after icv while increasing neuronal uptake in the arcuate nucleus and dorsomedial hypothalamus. Fluorocitrate also induced mild astrogliosis and moderately increased pSTAT3 immunopositive neurons in response to Alexa568-leptin in the dorsomedial hypothalamus. In the Western blotting study, A ^sup vy^ mice were pretreated with either PBS or fluorocitrate, and received PBS or leptin 1 h later followed by determination of pSTAT3 and GFAP expression an additional 30 min afterward. The results show that fluorocitrate induced a mild pSTAT3 activation but attenuated leptin-induced pSTAT3 activation and decreased GFAP expression independently of leptin treatment. We conclude that inhibition of astrocytic activity resulted in enhanced neuronal leptin uptake and signaling. This suggests opposite roles of astrocytes and neurons in leptin's actions in the A ^sup vy^ mouse with adult-onset obesity.[PUBLICATION ABSTRACT]