Paraventricular NUCB2/nesfatin-1 is directly targeted by leptin and mediates its anorexigenic effect.

An adipokine leptin plays a central role in the regulation of feeding and energy homeostasis via acting on the hypothalamus. However, its downstream neuronal mechanism is not thoroughly understood. The neurons expressing nucleobindin-2 (NUCB2)-derived nesfatin-1 in the hypothalamic paraventricular nucleus (PVN) have been implicated in feeding and energy homeostasis. The present study aimed to explore the role of PVN NUCB2/nesfatin-1 in the leptin action, by using adeno-associated virus (AAV) vectors encoding shRNA targeting NUCB2 (AAV-NUCB2-shRNA). Leptin directly interacted and increased cytosolic Ca(2+) in single neurons isolated from the PVN, predominantly in NUCB2/nesftin-1-immunoreactive neurons. Treatment with leptin in vivo and in vitro markedly increased NUCB2 mRNA expression in the PVN. Peripheral and central injections of leptin failed to significantly inhibit food intake in mice receiving AAV-NUCB2. These results indicate that PVN NUCB2/nesfatin-1 is directly targeted by leptin, and mediates its anorexigenic effect.