Evidence for the Neuronal Expression and Secretion of Adiponectin.

Peripheral adiponectin acts on the hypothalamus to inhibit energy expenditure and increase food intake through its receptors AdipoR1 and adipoR2. The hypothalamic expression of adiponectin is poorly documented. We hypothesize that whether hypothalamic adiponectin is confirmed, its expression and secretion could be regulated as peripheral adiponectin. Thus, in the present work, we aim to determine whether adiponectin is expressed in the hypothalamus and in two neuronal cell lines and investigate the potential mechanisms regulating its neuronal expression. Using immunohistochemistry, we show that adiponectin is expressed in the mediobasal hypothalamic neurons of mice. Adiponectin expression is also evidenced in two neuronal cell lines mHypo POMC (an adult mouse hypothalamic cell line) and SH-SY5Y (human neuroblastoma). The neuronal expression of adiponectin is increased in response to rosiglitazone treatment (a PPARγ agonist) and FGF21 and is decreased in insulin-resistant neurons. Furthermore, we show that adiponectin expressed by mHypo POMC neurons is secreted in a culture medium. Adiponectin also diminished the resistin-induced IL6 expression in SIMA9 cells, a microglia cell line. In conclusion, we evidenced the hypothalamic expression of adiponectin and its regulation at the neuronal level.