猪GnIH与GnRH介导的细胞内信号通路交联节点调控促性腺激素转录的机制

Gonadotropin-inhibitory hormone (GnIH) and Gonadotropin-releasing hormone (GnRH) are the most important neuroendocrine factors in modulating the vertebrate animal reproductive behavior. They coordinate and restrict with each other, in order to co-control the synthesis and secrete of gonadotropin. It is insufficient to expound the complexity of the neuroendocrine network by investigating the physiological function or molecular mechanism of GnIH and GnRH alone. In this research, Dominant negative mutation, Luciferase report gene and Western blot will be utilized to study the two neuroendocrine factors, porcine GnIH and GnRH, which shares contrary physiological functions but similar signal pathway. Gonadotropin which co-regulated by GnIH and GnRH will be considered the research object. The cross-talk nodes of signal pathway mediated by porcine GnIH and GnRH will be explored as same as the association of the cross-talk nodes and gonadotropin. The concrete mechanism of GnIH and GnRH regularing gonadotropin transcription in the respect of signal pathway will be clarified, and more evidences for the signal transduction network of GnIH and GnRH will be provided.

GnIH（Gonadotropin-inhibitory hormone，促性腺激素抑制激素）和GnRH（Gonadotropin-releasing hormone，促性腺激素释放激素）是动物生殖活动中两个非常重要的神经内分泌因子，两者相互协调相互制约，共同调控着促性腺激素的合成和分泌。单独研究GnIH和GnRH的生理功能或分子机制已远不能解释神经内分泌网络的复杂性。因此，本项目拟采用显性失活突变体、荧光素酶报告基因和Western blot等技术，首次将猪GnIH和GnRH这对生理功能相反但信号通路相似的神经内分泌因子一起作为研究对象，将两者的共同调控靶点促性腺激素作为研究目标，通过探寻猪GnIH和GnRH介导的信号通路交联节点，并将交联节点与促性腺激素的转导调控联系起来，从信号转导层面阐释GnIH和GnRH调控促性腺激素转录的具体机制，完善并丰富GnIH和GnRH介导的信号转导网络。

大量研究已证实GnIH和GnRH是动物生殖活动中非常重要的神经内分泌因子，两者相互协调相互制约，共同调控着促性腺激素的合成和分泌。单独研究GnIH和GnRH生理功能或分子机制已远不能解释神经内分泌网络的复杂性，因此，本项目将GnIH和GnRH这对生理功能相反但信号通路相似的神经内分泌因子联系起来，运用多种分子生物学技术及信号通路抑制剂这一经典的信号通路研究方法，得到以下研究结果：（1）GnIH受体可通过偶联Gαi/o抑制GnRH诱导的cAMP含量，证明GnRH和GnIH受体偶联Gα蛋白亚型为Gαs和Gαi/o。（2）GnIH在30 min内呈剂量依赖性显著抑制GnRH诱导的MAPKs磷酸化，并且ERK1/2、p38MAPK还是JNK抑制剂与GnIH协同作用均能分别显著抑制GnRH诱导下的MAPKs磷酸化，证明MAPKs是GnIH和GnRH信号通路交联节点之一。（3）GnIH在30 min时通过Ca2+电压门控通道呈剂量依赖性显著抑制GnRH诱导的Ca2+浓度，证明Ca2+是GnIH和GnRH信号通路另一个交联节点。（4）验证ERK和Ca2+为GnIH和GnRH调控猪促性腺激素α的交联节点；ERK为GnIH和GnRH调控LHβ的交联节点；ERK、JNK和Ca2+为GnIH和GnRH调控FSHβ的交联节点，明确GnIH和GnRH介导的信号通路中MAPKs和Ca2+参与调控促性腺激素转录的具体机制。综上所述，本项目通过验证GnIH和GnRH在信号通路层面的交互作用，并深入探索GnIH和GnRH在调控促性腺激素转录中的平衡机制，为GnIH和GnRH作为调控动物发情和生殖活动的作用因子提供理论依据，丰富并完善动物的生殖内分泌网络。