Wakitani Shoichi, Hondo Eiichi, Phichitraslip Thanmaporn, Stewart Colin Lawson, Kiso Yasuo
Department of Veterinary Anatomy, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan.
J Reprod Dev. 2008 Apr;54(2):113-6. doi: 10.1262/jrd.19120. Epub 2008 Jan 30.
Leukemia inhibitory factor (LIF) and Indian hedgehog (Ihh) are essential for embryo implantation in mice and are regulated by the actions of 17beta-estradiol (E2) and progesterone, respectively. The present study examined the effect of LIF on Ihh and Ihh-related factors in the uterine luminal epithelium during the implantation period using a DNA microarray. Expression of Ihh mRNA reached its peak on the forth day of pregnancy, and progesterone receptor (Pgr) mRNA decreased on the fifth day of pregnancy in wildtype mice. On the other hand, these changes in expression were not seen in LIF-/- mice. Ihh and Pgr mRNA were upregulated by LIF injection in delayed implantation mice. This up-regulation of Pgr was transient and preceded an increase of Ihh mRNA. Ihh mRNA also increased after E2 injection in delayed implantation mice of the LIF-/- genotype. E2 did not affect transcription of Pgr mRNA in the uterine luminal epithelium of delayed implantation LIF-/- mice. Using an antibody against the C-terminal epitope of Ihh, unprocessed Ihh proteins, but not C-terminal peptides, by autoproteolytic cleavage of Ihh were detected by western blot analysis. Unprocessed Ihh did not show quantitative changes between the wildtype and LIF-/- mice during the implantation period. Transcription of hedgehog acyltransferase was not influenced by LIF and E2 injection. In conclusion, LIF, which has a crucial role in E2 action for initiation of implantation, caused transient induction of Pgr mRNA and subsequent upregulation of Ihh mRNA, which mediates progesterone-Pgr actions for successful implantation.
白血病抑制因子（LIF）和印度刺猬因子（Ihh）对小鼠胚胎着床至关重要，且分别受17β-雌二醇（E2）和孕酮的调控。本研究使用DNA微阵列检测了着床期LIF对子宫腔上皮中Ihh及Ihh相关因子的影响。在野生型小鼠中，Ihh mRNA的表达在妊娠第4天达到峰值，孕酮受体（Pgr）mRNA在妊娠第5天下降。另一方面，在LIF基因敲除小鼠中未观察到这些表达变化。在延迟着床小鼠中，注射LIF可上调Ihh和Pgr mRNA的表达。Pgr的这种上调是短暂的，且先于Ihh mRNA的增加。在LIF基因敲除型延迟着床小鼠中，注射E2后Ihh mRNA也增加。E2不影响LIF基因敲除型延迟着床小鼠子宫腔上皮中Pgr mRNA的转录。通过蛋白质免疫印迹分析，使用针对Ihh C末端表位的抗体，检测到未经加工的Ihh蛋白，而非Ihh自蛋白水解切割产生的C末端肽。在着床期，野生型和LIF基因敲除小鼠之间未经加工的Ihh没有显示出定量变化。刺猬酰基转移酶的转录不受LIF和E2注射的影响。总之，LIF在E2启动着床的作用中起关键作用，它导致Pgr mRNA的短暂诱导，随后Ihh mRNA上调，Ihh介导孕酮-Pgr作用以实现成功着床。
