Zhang Huixian, Zhang Bo, Qin Geng, Li Shuisheng, Lin Qiang
CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Institution of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China.
University of Chinese Academy of Sciences, Beijing, China.
Front Neurosci. 2018 Dec 11;12:940. doi: 10.3389/fnins.2018.00940. eCollection 2018.
The kisspeptin/GPR54 system plays a crucial role in the regulation of the reproductive axis in vertebrates. Male pregnancy and ovoviviparity are special reproductive phenomena among vertebrates. To better understand the neuroendocrine mechanisms of male pregnancy, cDNAs encoding and GPR54 were cloned and functionally characterized from the lined seahorse, , an ovoviviparous teleost with male pregnancy. The core mature peptide of seahorse Kiss2 is high conserved among seahorses, but unique among vertebrate Kiss orthologs. In the phylogenic analysis, the seahorse Kiss clustered with the teleost Kiss2 clade. The transcripts were shown to be widely expressed in various tissues, notably in the brain and gonad of the seahorse, while GPR54-2 mRNA was expressed exclusively in the brain. In addition, mRNA found in male seahorse brain tissue increased significantly at the early pubertal stage, and decreased significantly during pregnancy. Intraperitoneal administration of seahorse Kiss2-10 to sexual mature male seahorses demonstrated to stimulate lutropin β (LHβ) and follitropin β (FSHβ) release and increased serum testosterone levels. In summary, we first identified the kisspeptin/GPR54 system in an ovoviviparous fish with male pregnancy, which might be involved in the regulation of the reproductive functions of pubertal onset, gonadal development, and male pregnancy via regulating the synthesis of both gonadotropic hormone (GTH) and testosterone.
亲吻素/GPR54系统在脊椎动物生殖轴的调节中起着关键作用。雄性怀孕和卵胎生是脊椎动物中的特殊生殖现象。为了更好地理解雄性怀孕的神经内分泌机制，从线纹海马（一种具有雄性怀孕的卵胎生硬骨鱼）中克隆了编码亲吻素和GPR54的cDNA并对其进行了功能表征。海马Kiss2的核心成熟肽在海马中高度保守，但在脊椎动物亲吻素直系同源物中是独特的。在系统发育分析中，海马亲吻素与硬骨鱼Kiss2进化枝聚类。亲吻素转录本在各种组织中广泛表达，特别是在海马的脑和性腺中，而GPR54-2 mRNA仅在脑中表达。此外，在雄性海马脑组织中发现的亲吻素mRNA在青春期早期显著增加，在怀孕期间显著下降。对性成熟雄性海马腹腔注射海马Kiss2-10可刺激促黄体生成素β（LHβ）和促卵泡生成素β（FSHβ）释放，并提高血清睾酮水平。总之，我们首次在具有雄性怀孕的卵胎生鱼类中鉴定出亲吻素/GPR54系统，该系统可能通过调节促性腺激素（GTH）和睾酮的合成参与青春期启动、性腺发育和雄性怀孕的生殖功能调节。
