Endocannabinoid Signaling in Modulating Periimplantation Events

Cannabinoids have long been suspected associating with abnormal fetal growth and outcome. However, the molecular mechanisms in which they are involved had long been obscure for several decades. Only recently, after the identification of two types of cannabinoid receptors （CB1-R and CB2-R） and the following discoveries of their corresponding endogenous ligands, the mystery behind those seemingly facts began gradually unveiled. Through a series of landmark research, it is now indicated that the endocannabinoid signaling via the ligand-receptor interaction plays an important role in modulating early development of preimplantation embryo and synchronizing embryo development with uterine receptivity for implantation. Current data suggest that the physiological functions their metabolic pathways are potentially very of endocannabinoid signaling as well as exited areas to be explored further. This review will first introduce the reproductive functions of endocannabinoid signaling from epidemiological and molecular background, then focus on its reciprocal interactions between the embryo and maternal tissues, as well as related metabolic aspects in regards to implantation. It is hoped that further investigation of this physiologically fundamental signaling will generate more exciting information elucidating the complexity of implantation thus lead to a better control of human reproduction.

Relevance of Hepatocyte Growth Factor and Fibroblast Growth Factor on Mouse Preimplantation Embryo Development

Objective To explore the effect of hepatocyte growth factor （HGF） and fibroblast growth factor （FGF） on preimplantation embryo development of mouse.Methods Mated mice were killed by cervical dislocation to collect two pronucleous （2 PN） zygotes from oviduct of pregnant 1 d NMRI mice and were cultured to the hatching blastocyst stage and the number of embryo in different stages was recorded under an invert microscope. The cleavage rates of formed 2 PN zygotes were compared with blastocyst and hatching blastocyst stage in drops of T6 medium with or without HGF or FGF （0 ng/ml, 10 ng/ml, 20 ng/ml, 50 ng/ml, 1 000 ng/ml）. Results HGF and FGF enriched embryo culture media promotea the aevetopment from 2 PN stage embryos to blastocyst. Adding 20 ng/ml of FGF or HGF to the culture medium significantly increased the percentage of 2PN embryos that developed into blastocysts （P〈0.05）, but culture of embryos in drops of T6 medium with HGF （20 ng/ml） had no improvement in in-vitro hatching.Conclusion Exogenous HGF and FGF at low concentrations promote in-vitro mouse blastocyst formation.

Genomewide decoupling of H2AK119ub1 and H3K27me3 in early mouse development

Polycomb group(Pc G)proteins are crucial chromatin regulators during development.H2 AK119 ub1(H2 Aub)and H3 K27 me3 are catalyzed by Polycomb-repressive complex 1 and 2(PRC1/2)respectively,and they largely overlap in the genome due to mutual recruitment of the two complexes.However,it is unclear whether PRC1/H2 Aub and PRC2/H3 K27 me3 can also function independently.By developing an ultra-sensitive carrier-DNA-assisted chromatin immunoprecipitation sequencing method termed CATCH-Seq,we generated allelic H2 Aub profiles in mouse gametes and early embryos.Our results revealed an unexpected genomewide decoupling of H2 Aub and H3 K27 me3 in mouse preimplantation embryos,where H2 Aub but not H3 K27 me3 was enriched at Pc G targets while only H3 K27 me3 was deposited in the broad distal domains associated with DNA methylation-independent non-canonical imprinting.These observations suggest that H2 Aub represses future bivalent genes during early embryogenesis without H3 K27 me3,but it is not required for the maintenance of non-canonical imprinting,which is mediated by maternal H3 K27 me3.Thus,our study reveals the distinct depositions and independent functions of H2 Aub and H3 K27 me3 during early mammalian development.

Effect of the P1 Medium and the ECM Medium on Embryo Quality in IVF

Objective To investigate the effect of the glucose-free preimplantation stage one （P1） medium and the ECM medium on embryo development quality in IVF. Methods The patients with ≥4 zygotes of 2PN were studied. A total of 201 retrieval cycles were included in a prospective randomized study. Each patient was herself control. Half of zygotes of 2PN were transferred into ECM medium （group A） and half into P1 medium （group B）for further culture. Embryo development was evaluated on the day of embryo transfer. The efficacy of ECM was compared with P1 as culture medium for the development of preimplantation embryos. Results No statistically significant differences were noted between the two groups regarding embryo-cleavage rate （97.13% vs 97.55%） and rate of normal-cleaving embryos （58.29% and 58.37%）. The rate of top-quality embryos was statistically higher in group A than in group B （27.59% vs 19.75%, P〈O.05）. Embryo quality, as assessed by morphological parameters （the amount of detached anuclear fragments 〉30%）, was better in group A than in group B （19.86% vs 21.75%）, however, there was no statistically significance. Both the rate of good-quality embryos （47.95% vs 46.17%） and available embryos （63.22% vs 61.19%） were higher in group A than in group B, but there was also no statistically significance. Conclusion The ECM medium may be associated with a better embryo quality compared with the P1 medium.