Deciphering The Role Of Kisspeptin In The Mediation Of Photoperiod and Gonadal Steroid Signalling Throughout Reproduction

解读 Kisspeptin 在整个生殖过程中光周期和性腺类固醇信号调节中的作用

• 批准号: 1147118
• 负责人: Yonathan Zohar
• 金额: $ 15万
• 依托单位: University of Maryland Baltimore County
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2014-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1147118&HistoricalAwards=false
• 关键词: Deciphering; Role; Kisspeptin; Mediation; Photoperiod

Kisspeptin is emerging as an important regulator of reproduction in vertebrates. In mammals, it is considered to be the "missing link" that mediates environmental and endogenous information to the hypothalamic-pituitary-gonadal (HPG) axis via integration of sensory input and transmission to gonadotropin-releasing hormone (GnRH) neurons. Accumulating evidence suggests that the kisspeptin system acts similarly in teleosts, which comprise the largest class of vertebrates. However, the study of teleost kisspeptin lags significantly behind that of mammals. Unlike mammals that possess only single forms of kisspeptin (KiSS1) and its receptor (KiSS1R), two isoforms of kisspeptin (Kiss1 and Kiss2) and two receptors (Kiss1r and Kiss2r) are expressed in the brain of most teleost species. Each receptor is activated by the two kisspeptin forms but shows preference to one form of kisspeptin. Preliminary data in striped bass suggests that the two kisspeptins have differential roles in the control of reproduction. Moreover, kiss1r- and kiss2r-expressing neurons interact in different ways with GnRH neurons in the hypothalamic preoptic area. To elucidate the exact roles of each form, the kisspeptins and cognate receptors of the striped bass will be used to pursue specific, selective, and efficient antagonists for the teleost kisspeptin receptors. As a first step, a suite of systematically modified kisspeptin peptides will be screened in vitro for their ability to block kiss1r and kiss2r stably expressed in a COS7 cell line, via two signal transduction pathways, PKC and PKA. The selected candidates will then be evaluated in vivo for their biological potencies, efficiency and specificity in short term and long term treatments. In the short-term experiments, kiss1 or kiss2 will be co-injected with the tested antagonist into striped bass. Controlled release delivery implants will be utilized in the long term experiments. These devices will be pre-implanted two weeks prior to kiss1 or kiss2 injections. The ability to block kiss1 and kiss2 will be determined by comparison to known kiss1/kiss2 effects on key hormones within the reproductive system (GnRHs, LH and FSH). The study is expected to yield at least one potent specific antagonist for each kisspeptin receptor, thereby enabling studies on the exact roles and significance of each of the two kisspeptin systems in the mediation of different signals in various brain pathways, particularly those affecting the reproductive axis. This tool will pave the way for a wider range of studies in the field of reproductive endocrinology in vertebrates. The potential impacts include improvement of reproductive manipulations of farmed and captive animals.

Kisspeptin正在成为脊椎动物生殖的重要调节因子。在哺乳动物中，它被认为是通过整合感觉输入和传递到促性腺激素释放激素（GnRH）神经元将环境和内源性信息介导到下丘脑-垂体-性腺（HPG）轴的“缺失环节”。越来越多的证据表明，kisspeptin系统在硬骨鱼类中起着类似的作用，硬骨鱼类是脊椎动物中最大的一类。然而，硬骨鱼kisspeptin的研究明显落后于哺乳动物。与只具有单一形式的kisspeptin（KiSS 1）及其受体（KiSS 1 R）的哺乳动物不同，kisspeptin的两种亚型（Kiss 1和Kiss 2）和两种受体（Kiss 1 r和Kiss 2 r）在大多数硬骨鱼类物种的脑中表达。每个受体都被两种kisspeptin形式激活，但对一种kisspeptin形式表现出偏好。 条纹鲈鱼的初步数据表明，这两种kisspeptins在控制繁殖方面具有不同的作用。此外，kiss 1 r和kiss 2 r表达神经元以不同的方式与下丘脑视前区的GnRH神经元相互作用。为了阐明每种形式的确切作用，kisspeptin和条纹鲈鱼的同源受体将被用来追求特异性，选择性和有效的拮抗剂的硬骨鱼kisspeptin受体。作为第一步，将在体外筛选一套系统修饰的kisspeptin肽，以确定其通过两种信号转导途径PKC和PKA阻断COS 7细胞系中稳定表达的kiss 1 r和kiss 2 r的能力。然后将在体内评价所选候选药物在短期和长期治疗中的生物学效价、有效性和特异性。在短期实验中，将kiss 1或kiss 2与测试拮抗剂共注射到条纹鲈鱼中。控释递送植入物将用于长期实验。这些器械将在kiss 1或kiss 2注射前两周预植入。通过与已知kiss 1/kiss 2对生殖系统内关键激素（GnRHs、LH和FSH）的影响进行比较，确定阻断kiss 1和kiss 2的能力。该研究预计将产生至少一种针对每个kisspeptin受体的有效特异性拮抗剂，从而能够研究两个kisspeptin系统中的每一个在各种脑通路中介导不同信号的确切作用和意义，特别是影响生殖轴的那些。这一工具将为脊椎动物生殖内分泌学领域更广泛的研究铺平道路。潜在的影响包括改善养殖和圈养动物的繁殖操作。