Fujima S, Amemiya N, Arima T, Sano Y, Furuichi T. CAPS2 deficiency induces proopiomelanocortin accumulation in pituitary and affects food intake behavior in mice.
Neurosci Lett 2020;
738:135335. [PMID:
32891671 DOI:
10.1016/j.neulet.2020.135335]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 08/11/2020] [Accepted: 08/26/2020] [Indexed: 10/23/2022]
Abstract
Proopiomelanocortin (POMC) is a neuropeptide precursor produced in the anterior and intermediate pituitary lobes, the hypothalamic arcuate nucleus (ARC), and solitary tract nucleus. Alpha-melanocyte-stimulating hormone (α-MSH) is a cell type specific POMC derivative that is essential for regulating feeding, and energy homeostasis. However, the molecular mechanism underlying POMC/α-MSH secretion remains unclear. Ca2+-dependent activator protein for secretion 2 (CAPS2) is a regulatory protein involved in the exocytosis of dense-core vesicles containing neuropeptides. We previously reported CAPS2 localization in the intermediate pituitary lobe and reduced body weights in Caps2-knockout (Caps2-KO) mice, compared to control mice. Here, we aimed to investigate CAPS2 expression in POMC-expressing neurons and the effects of CAPS2 deficiency on the secretion of POMC-related peptides and feeding behavior phenotype. CAPS2 was localized in the POMC-expressing neurons of the intermediate pituitary lobe, hypothalamic ARC, and the paraventricular nucleus, which is innervated by hypothalamic neurons. POMC protein levels in the intermediate pituitary lobe of Caps2-KO mice were significantly higher than that in the control mice, suggesting a possible accumulation of POMC-derived peptides in the intermediate pituitary lobe of Caps2-KO mice. Moreover, administration of low-dose melanotan-2, an α-MSH receptor (MC4R) agonist, decreased food intake per body weight in Caps2-KO mice; no such effect was observed in the wildtype mice. Collectively, these results suggest that CAPS2 is involved in regulating the secretion of POMC-derived peptides, including α-MSH, is partially associated with feeding, and affects energy metabolism.
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