Wang Bin, Yang Guokun, Xu Yongjiang, Zhang Yaxing, Liu Xuezhou
Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, China; Laboratory for Marine Fisheries and Food Production Processes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China.
Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, College of Fisheries, Henan Normal University, Xinxiang, 453007, China.
Anim Reprod Sci. 2019 Apr;203:1-9. doi: 10.1016/j.anireprosci.2019.01.009. Epub 2019 Feb 15.
Results of previous studies indicated the existence of LPXRFa, the piscine ortholog of gonadotropin-inhibitory hormone (GnIH), and kisspeptin (Kiss2) in tongue sole (Cynoglossus semilaevis), and that LPXRFa exerts an inhibitory effect on Kiss2 activation in the protein kinase A (PKA) pathway. The functions in the control of reproduction and whether LPXRFa antagonizes the action of Kiss2 by inhibiting the protein kinase C (PKC) pathway, however, are still unknown. In the present study, there was an initial investigation of the direct effects of LPXRFa and Kiss2 on relative abundance of pituitary hormone mRNA transcripts using a whole pituitary culture system. Results indicated that LPXRFa-1 specifically functioned to increase relative abundance of lhβ mRNA when there were comparisons with the control, without any effect on relative abundance of gh, gthα and fshβ mRNA. Treatment with LPXRFa-2 resulted in a reduction in relative abundance of gthα and lhβ mRNA, and did not alter relative abundance of fshβ mRNA. Treatment of LPXRFa-2 resulted in a greater relative abundance of gh mRNA. Treatment with Kiss2, however, resulted in an increase in relative abundance of gthα and fshβ mRNA transcripts, without altering relative abundances of gh and lhβ mRNA. Subsequently, there was valuation of the potential interaction between LPXRFa and kisspeptin in COS-7 cells transfected with the cognate receptors. Both LPXRFa-1 and LPXRFa-2 suppressed serum responsive element-dependent luciferase (SRE-luc) activity when compared to stimulation with Kiss2 alone, indicating an inhibitory effect of LPXRFa on kisspeptin activation on the PKC pathway. Overall, data from the present study provide novel evidence for differential actions of LPXRFa and kisspeptin on pituitary hormone synthesis as well as for the interaction between LPXRFa and kisspeptin systems in teleosts.
先前研究结果表明，半滑舌鳎（Cynoglossus semilaevis）中存在促性腺激素抑制激素（GnIH）的鱼类直系同源物LPXRFa和亲吻素（Kiss2），并且LPXRFa在蛋白激酶A（PKA）途径中对Kiss2激活发挥抑制作用。然而，其在生殖控制中的功能以及LPXRFa是否通过抑制蛋白激酶C（PKC）途径拮抗Kiss2的作用仍不清楚。在本研究中，使用全垂体培养系统初步研究了LPXRFa和Kiss2对垂体激素mRNA转录本相对丰度的直接影响。结果表明，与对照组相比，LPXRFa-1特异性地发挥作用，增加lhβ mRNA的相对丰度，而对gh、gthα和fshβ mRNA的相对丰度没有任何影响。用LPXRFa-2处理导致gthα和lhβ mRNA的相对丰度降低，并且没有改变fshβ mRNA的相对丰度。LPXRFa-2处理导致gh mRNA的相对丰度更高。然而，用Kiss2处理导致gthα和fshβ mRNA转录本的相对丰度增加，而没有改变gh和lhβ mRNA的相对丰度。随后，评估了在转染了同源受体的COS-7细胞中LPXRFa和亲吻素之间的潜在相互作用。与单独用Kiss2刺激相比，LPXRFa-1和LPXRFa-2均抑制血清反应元件依赖性荧光素酶（SRE-luc）活性，表明LPXRFa对PKC途径中亲吻素激活具有抑制作用。总体而言，本研究的数据为LPXRFa和亲吻素对垂体激素合成的不同作用以及硬骨鱼中LPXRFa和亲吻素系统之间的相互作用提供了新的证据。
