Gonadotropin-releasing hormone, kisspeptin, and gonadal steroids directly modulate nucleobindin-2/nesfatin-1 in murine hypothalamic gonadotropin-releasing hormone neurons and gonadotropes.
Neuroendocrine regulation of metabolism and reproduction are tightly interlinked. Nesfatin-1 is an 82 amino acid metabolic peptide derived from nucleobindin-2 (NUCB2). NUCB2 mRNA and protein significantly increase in the hypothalamus of rats during puberty-to-adult transition. Administration of nesfatin-1 modulates circulating LH and testosterone in male rats. However, whether nesfatin-1 acts directly on neurons and gonadotropes remain unknown. In addition, whether reproductive hormones of the hypothalamo-pituitary gonadal axis modulate NUCB2/nesfatin-1 is unclear. To address these, we employed murine hypothalamic (GT1-7) and pituitary (LβT2) cells in vitro. Nucb2 expression, and NUCB2/nesfatin-1 immunoreactivity were observed in both GT1-7 and LβT2 cells, and in the hypothalamus of mice. Nesfatin-1 co-localized GnRH in GT1-7 cells, and in the hypothalamic perikarya of mice. Cells were treated with kisspeptin, GnRH, and estradiol and testosterone, as well as nesfatin-1 for 2, 6 or 24 hours. Synthetic nesfatin-1 increased Kiss1r and Gnrh expression in GT1-7 cells and Lhβ in LβT2. Nesfatin-1 increased GnRH and LHβ protein expression in GT1-7 and LβT2 at 6-hour post incubation respectively. Both NUCB2 mRNA and protein were increased in GT1-7 cells treated with kisspeptin. Testosterone increased NUCB2 mRNA and protein expression in GT1-7 and LβT2. 17β-estradiol increased NUCB2 mRNA and protein expression in LβT2. Nesfatin-1 acts directly on hypothalamic neurons and gonadotropes to elicit a generally positive influence on the endocrine milieu regulating reproduction in mice. Reproductive hormones, in turn, modulate brain and pituitary NUCB2/nesfatin-1. In conclusion, we provide additional information to designate nesfatin-1 as a novel, additional factor that helps reproductive success.
Department of Veterinary Biomedical Sciences, Laboratory of Integrative Neuroendocrinology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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Hatef
Department of Veterinary Biomedical Sciences, Laboratory of Integrative Neuroendocrinology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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Unniappan
D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004958:Estradiol; D047628:Estrogen Receptor alpha / Q000378:metabolism; D052681:Gonadotrophs / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism*; D059648:Kisspeptins; D051379:Mice; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D000080866:Nucleobindins; D000074502:Receptors, Kisspeptin-1 / Q000378:metabolism*; D013739:Testosterone
D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D047628:Estrogen Receptor alpha; C492248:Kiss1r protein, mouse; D059648:Kisspeptins; D009419:Nerve Tissue Proteins; C000630651:Nucb1 protein, mouse; C000630652:Nucb1 protein, rat; D000080866:Nucleobindins; D000074502:Receptors, Kisspeptin-1; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D004958:Estradiol
GnRH; LHβ; NUCB2/nesfatin-1; RT- qPCR; hypothalamus; pituitary; western blot