Jia-Sen Xu

The embryotrophic activity of oviductal cell-derived complement C3b and iC3b, a novel function of complement protein in reproduction.

The oviduct-derived embryotrophic factor, ETF-3, enhances the development of trophectoderm and the hatching process of treated embryos. Monoclonal anti-ETF-3 antibody that abolishes the embryotrophic activity of ETF-3 recognized a 115-kDa protein from the conditioned medium of immortalized human oviductal cells. Mass spectrometry analysis showed that the protein was complement C3. Western blot analysis using an antibody against C3 confirmed the cross-reactivities between anti-C3 antibody with ETF-3 and anti-ETF-3 antibody with C3 and its derivatives, C3b and iC3b. Both derivatives, but not C3, were embryotrophic. iC3b was most efficient in enhancing the development of blastocysts with larger size and higher hatching rate, consistent with the previous reported embryotrophic activity of ETF-3. Embryos treated with iC3b contained iC3b immunoreactivity. The oviductal epithelium produced C3 as evidenced by the presence of C3 immunoreactivity and mRNA in the human oviduct and cultured oviductal cells. Cyclical changes in the expression of C3 immunoreactivity and mRNA were also found in the mouse oviduct with the highest expression at the estrus stage. Molecules involving in the conversion of C3b to iC3b and binding of iC3b were present in the human oviduct (factor I) and mouse preimplantation embryo (Crry and CR3), respectively. In conclusion, the present data showed that the oviduct produced C3/C3b, which was converted to iC3b to stimulate embryo development.

Temporal Effect of Human Oviductal Cell and Its Derived Embryotrophic Factors on Mouse Embryo Development

Abstract Mouse embryos at different stages of development were cocultured with human oviduct cells or cultured in the presence of oviduct-derived embryotrophic factor-1, -2, and -3 (ETF-1, -2, and -3) for various amounts of time within the preimplantation period. Cocultures that included the period from 48 to 72 h post-hCG stimulated cell division and increased the cell numbers in the inner cell mass (ICM) of the exposed blastocyst. Exposure of embryos to oviductal cells from 96 to 120 h post-hCG increased the cell number in the trophectoderm (TE), blastocyst size, hatching rate, attachment, and in vitro spreading of the blastocyst. ETF-1 and ETF-2 affected embryos between 48 and 72 h post-hCG by increasing the number of cells in the ICM. In contrast, ETF-3 had a more profound effect on embryos that were exposed from 96 to 120 h post-hCG, where it mostly affected the development of TE cells, leading to higher hatching rate. Human oviductal cells improved mouse embryo development partly by the production of high molecular weight embryotrophic factors. These factors had differential effects on mouse embryo development.

Identification of mRNAs that are up-regulated after fertilization in the murine zygote by suppression subtractive hybridization.

Transcriptions occur in mouse preimplantation embryos as early as one-cell stage. However, our understanding on gene expression at this stage is lacking. The present study applied suppression subtractive hybridization (SSH) to compared gene expression profiles of mouse zygote and oocyte. Forty-four differentially expressed genes were selected and shown positive signals by reverse dot-blot hybridization. DNA sequences comparison of these putative clones with the GenBank/EMBL databases using BLAST search identified 38 clones with >90% identity to known genes and six novel clones with less than 70% homology to the databases. Eleven out of the 44 differentially expressed clones were either originally isolated from male embryo or testis-specific genes, suggesting that these genes may be derived from paternal genome. Five differentially expressed genes of interest, including bromodomain-containing protein BP75, spindlin, radixin, pituitary tumor-transforming gene (PTTG), and proteoglycan core protein (serglycin) were further studied by semi-quantitative RT-PCR. It is noted that spindlin which involves in cell division is highly expressed in zygote, suggesting that this protein may play an important role in zygotic gene activation (ZGA) and early stage development in 1-cell stage mouse embryos.

Vero cells, but not oviductal cells, increase the hatching frequency and total cell count of mouse blastocysts partly by changing energy substrate concentrations in culture medium

AbstractPurpose: To investigate the embryotrophic mechanisms of Vero and oviductal cells coculture. Methods: Mouse embryos were cultured in Chatot, Ziomek, and Bavister medium (CZB), in modified CZB media (MM) with nutrient concentrations adjusted to that found in conditioned media after different periods of Vero cells or oviductal cells culture, in reconstituted medium (RM) containing the purified >100-kDa components of Vero cell conditioned medium that had been reconstituted with CZB medium, and cocultured with Vero cells with an interposing membrane. Results: The blastulation rate was not different among embryos cultured in different Vero-cell–derived MMs. Nine-hour Vero-cell-derived MM significantly increased the total cell number and hatching frequency of the embryos. There was no difference in these parameters with oviductal-cell–derived MMs. The RM of Vero cells did not possess embryotrophic activity. The presence of a porous membrane between Vero cells and embryos did not affect the embryotrophic activity of coculture. Conclusions: Vero cells, but not oviductal cells, improved mouse embryo development partly by modifying the energy substrate concentration in culture medium.

The incidence of cytoplasmic fragmentation in mouse embryos in vitro is not affected by inhibition of caspase activity

OBJECTIVE To investigate the relationship between cytoplasmic fragmentation and caspase activity in the mouse embryo. DESIGN Experimental laboratory study. SETTING University gynacology unit. ANIMAL(S) One-cell zygote of mouse (MF1 x BALB/c). INTERVENTION(S) Mouse embryos were treated with caspase inhibitors: benzyloxycarbonyl-Val-Ala-Asp fluoromethylketone (z-VAD-fmk) and benzyloxycarbonyl-Asp-glu-Val-Asp-fluoromethyl ketone (Z-DEVD-fmk). MAIN OUTCOME MEASURE(S) Morphological development of the embryo, proportion of fragmented embryos, caspase-3-like activity, DNA breakage, and phosphatidylserine exposure in blastomeres. RESULT(S) The proportion of embryo reaching two-cell, three- to four-cell, and morula stage at 48, 72, and 96 hours after hCG administration, respectively, were comparable between the control embryos and those treated with either z-VAD-fmk or z-DEVD-fmk, at three concentrations (10 microM, 50 microM, and 200 microM). Although the inhibitors suppressed the caspase-3-like activity in the embryo fragment before compaction and decreased DNA breakages, there was no statistically significant difference in the percentage of fragmented embryo between the control and those treated with caspase inhibitors. The inhibitors did not affect the incidence of phosphatidylserine exposure in the blastomere of the treated embryos. CONCLUSION(S) Cytoplasmic fragmentation in precompaction mouse embryos is not a consequence of caspase-related apoptosis.

Coculture of human oviductal cells maintains mitochondrial function and decreases caspase activity of cleavage- stage mouse embryos

OBJECTIVE To investigate the mitochondrial function and caspase activity in mouse embryos after human oviductal cell coculture. DESIGN Experimental laboratory study. SETTING University gynecology unit. ANIMAL(S) MF-1 (female); BALB/c (male) mice. INTERVENTION(S) Mouse embryos were cocultured with human oviductal cells. MAIN OUTCOME MEASURE(S) Mitochondrial transmembrane potential (Delta psi(m)) and caspase activity. RESULT(S) Compared to embryos after coculture in Chatot-Ziomek-Bavister (CZB) medium supplemented with 0.5 mg/mL of BSA (CZB), Delta psi m of embryos cultured in CZB was significantly lower at the two-cell (CZB, 2.04 +/- 0.412; coculture, 4.34 +/- 0.563) and morula (CZB, 6.06 +/- 0.548; coculture, 7.12 +/- 0.568) stages. Cocultured embryos and in vivo developed embryos had comparable Delta psi m. Caspase activity was not detected in unfragmented cleavage-stage embryos and morula developed in vivo. In vitro cultured morula possessed caspase activity. The activity was significantly reduced in the cocultured morula. CONCLUSION(S) Human oviductal cells maintained the mitochondria function in terms of mitochondrial transmembrane potential and decreased the caspase activity to improve the development of mouse embryo.