title: Duplication of neuropeptide Y and peptide YY in Nile tilapia Oreochromis niloticus and their roles in food intake regulation.
abstract: In vertebrates, the neuropeptide Y (NPY) family peptides have been recognized as key players in food intake regulation. NPY centrally promotes feeding, while peptide YY (PYY) and pancreatic polypeptide (PP) mediate satiety. The teleost tetraploidization is well-known to generate duplicates of both NPY and PYY; however, the functional diversification between the duplicate genes, especially in the regulation of food intake, remains unknown. In this study, we identified the two duplicates of NPY and PYY in Nile tilapia (Oreochromis niloticus). Both NPYa and NPYb were primarily expressed in the central nervous system (CNS), but the mRNA levels of NPYb were markedly lower than those of NPYa. Hypothalamic mRNA expression of NPYa, but not NPYb, decreased after feeding and increased after 7-days of fasting. However, both NPYa and NPYb caused a significant increase in food intake after an intracranial injection of 50ng/g body weight dose. PYYb, one of the duplicates of PYY, had an extremely high expression in the foregut and midgut, whereas another form of duplicate PYYa showed only moderate expression in the CNS. Both hypothalamic PYYa and foregut PYYb mRNA expression increased after feeding and decreased after 7-days of fasting. Furthermore, the intracranial injection of PYYb decreased food intake, but PYYa had no significant effect. Our results suggested that although the mature peptides of NPYa and NPYb can both stimulate food intake, NPYa is the main endogenous functional NPY for feeding regulation. A functional division has been identified in the duplicates of PYY, which deems PYYb as a gut-derived anorexigenic peptide and PYYa as a CNS-specific PYY in Nile tilapia.
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, South China Sea Bio-Resource Exploitation and Collaborative Innovation Center, Research Institute of Sun Yat-Sen University in Shen Zhen, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, PR China.
authors.forename: Peipei
authors.initials: P
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, South China Sea Bio-Resource Exploitation and Collaborative Innovation Center, Research Institute of Sun Yat-Sen University in Shen Zhen, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, PR China.
authors.forename: Jirong
authors.initials: J
authors.lastname: Jia
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, South China Sea Bio-Resource Exploitation and Collaborative Innovation Center, Research Institute of Sun Yat-Sen University in Shen Zhen, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, PR China.
authors.forename: Guokun
authors.initials: G
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, South China Sea Bio-Resource Exploitation and Collaborative Innovation Center, Research Institute of Sun Yat-Sen University in Shen Zhen, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, PR China.
authors.forename: Dongfang
authors.initials: D
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, South China Sea Bio-Resource Exploitation and Collaborative Innovation Center, Research Institute of Sun Yat-Sen University in Shen Zhen, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, PR China.
authors.forename: Caiyun
authors.initials: C
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, South China Sea Bio-Resource Exploitation and Collaborative Innovation Center, Research Institute of Sun Yat-Sen University in Shen Zhen, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, PR China. Electronic address: lsslws@mail.sysu.edu.cn.
authors.forename: Wensheng
authors.initials: W
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001069:Appetite Regulation / Q000235:genetics; D023681:Cichlids / Q000378:metabolism; D004435:Eating / Q000235:genetics*; D007031:Hypothalamus / Q000378:metabolism; D009478:Neuropeptide Y / Q000235:genetics / Q000378:metabolism*; D010191:Pancreatic Polypeptide / Q000235:genetics / Q000378:metabolism*; D019894:Peptide YY / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D017476:Receptors, Neuropeptide Y / Q000235:genetics / Q000378:metabolism
chemical_list: D009478:Neuropeptide Y; D012333:RNA, Messenger; D017476:Receptors, Neuropeptide Y; D019894:Peptide YY; D010191:Pancreatic Polypeptide
keywords: Food intake; Neuropeptide Y; Nile tilapia; Peptide YY