PTHLH在小鼠着床前胚胎发育中作用机制的研究

Parathyroid hormone-like hormone (PTHLH), also known as parathyroid hormone-related protein (PTHrP), is expressed in multiple tissues and has multiple physiological functions, including the regulation of morphogenesis, cell proliferation and differentiation, and transplacental calcium transport. Our previous results showed that Pthlh is expressed in mouse oocytes and preimplantation embryos at all developmental stages, with the highest expression at the MII stage of the oocytes and the lowest expression at the blastocyst stage of the preimplantation embryos. The siRNA-mediated depletion of Pthlh at the MII stage oocytes or the 1-cell stage embryos significantly decreased the blastocyst formation rate, while this effect could be corrected by culturing the Pthlh depleted embryos in the medium containing PTHLH protein. Our previous results also showed that the expression of the transcription factors/pluripotency-related genes Oct4 and Nanog was significantly reduced in Pthlh-depleted embryos at the morula stage, and the histone acetylation patterns were altered by Pthlh depletion as well. Although there is no evidence showing that the PTHLH affects the transcription factors directly or exerts the direct effects on histone acetylation during preimplantation embryonic development, the previous studies have showed that the PTHLH can play roles through a complex network of signaling pathways involving cAMP, PKA，PKC, ERK/MAPK and HDAC4/MEF2 pathways. In this study, we plan to further clarify the mechanism of the regulation of PTHLH on the expression of the pluripotency-related genes and histone acetylation patterns by investigating the genes/proteins of the cAMP, PKA，PKC, ERK/MAPK and HDAC4/MEF2 pathways during mouse preimplantation embryonic development. We also plan to further study the effects of PTHLH on the development of cloned embryos in vitro and compare the mechanism with TSA treatment. These studies will help us to understand the molecular mechanism of early embryonic development and the nuclear reprogramming in mammals, which will provide a theoretical basis for human health.

PTHLH在多种组织中均有表达，在形态发生、细胞生长与分化的调控和胎盘钙的转运等方面发挥着广泛的作用。我们前期的研究结果首次证明，Pthlh在小鼠卵母细胞和各阶段着床前胚胎中均表达，发现Pthlh缺失显著影响囊胚发育率，还发现Pthlh对转录因子/多能性基因Oct4和Nanog在小鼠着床前胚胎的表达以及胚胎的组蛋白乙酰化模式都有显著影响，但是作用机制还不清楚。我们计划通过检测Pthlh缺失对cAMP、PKA、PKC、ERK/MAPK和HDAC4/MEF2的信号通路相关基因和蛋白、转录因子/多能性基因的表达及组蛋白乙酰化模式的影响，阐明PTHLH影响着床前胚胎转录因子/多能性基因表达和组蛋白乙酰化模式的分子机制，并通过与TSA的作用机制进行比较，进一步探讨PTHLH对小鼠体细胞克隆胚胎发育的作用机制，增强对哺乳动物早期胚胎发育分子机制和体细胞重编程机制的理解，为人类健康提供理论基础。

PTHLH在多种组织中均有表达，在形态发生、细胞生长与分化的调控和胎盘钙的转运等方面发挥着广泛的作用。我们以前的研究结果证明了Pthlh缺失显著影响囊胚发育率，发现了Pthlh对转录因子/多能性基因Oct4和Nanog在小鼠着床前胚胎的表达以及胚胎的组蛋白乙酰化模式都有显著影响。本项目通过检测Pthlh缺失对cAMP、PKA、PKC、ERK/MAPK和HDAC4/MEF2的信号通路相关基因和蛋白、转录因子/多能性基因的表达及组蛋白乙酰化模式的影响，明确了PTHLH影响着床前胚胎转录因子/多能性基因表达和组蛋白乙酰化模式的分子机制，增强了对哺乳动物早期胚胎发育分子机制和细胞重编程机制的理解。