Yuanqing Yao

Detection and quantitation of chromosomal mosaicism in human blastocysts using copy number variation sequencing

Currently, our understanding of the nature and reproductive potential of blastocysts associated with trophectoderm (TE) lineage chromosomal mosaicism is limited. The objective of this study was to first validate copy number variation sequencing (CNV‐Seq) for measuring the level of mosaicism and second, examine the nature and level of mosaicism in TE biopsies of patients blastocysts.

The clinical utility of next-generation sequencing for identifying chromosome disease syndromes in human embryos.

Next-generation sequencing is emerging as a reliable and accurate technology for pre-implantation genetic diagnosis (PGD) of aneuploidies and translocations. The aim of this study was to extend the clinical utility of copy number variation sequencing (CNV-Seq) to the detection of small pathogenic copy number variations (CNVs) associated with chromosome disease syndromes. In preliminary validation studies, CNV-Seq was highly sensitive and specific for detecting small CNV in whole-genome amplification products from three replicates of one and five cell samples, with a resolution in the order of 1-2 Mb. Importantly, the chromosome positions of all CNV were correctly mapped with copy numbers similar to those measured in matching genomic DNA samples. In seven clinical PGD cycles where results were obtained for 34 of 35 blastocysts, CNV-Seq identified 18 blastocysts with aneuploidies, one with an aneuploidy and a 4.98 Mb 5q35.2-qter deletion associated with Sotos syndrome, one with a 6.66 Mb 7p22.1-pter deletion associated with 7p terminal deletion syndrome and 14 with no detectable abnormalities that were suitable for transfer. On the basis of these findings, CNV-Seq displays the hallmarks of a comprehensive PGD technology for detection of aneuploidies and CNVs that are known to affect the development and health of patients embryos.

The human leukocyte antigen G promotes trophoblast fusion and β-hCG production through the Erk1/2 pathway in human choriocarcinoma cell lines.

The human leukocyte antigen G (HLA-G) is expressed on the fetal-maternal interface and plays a role in protecting fetal-derived trophoblasts from the maternal immune response, allowing trophoblasts to invade the uterus. However, HLA-G also possesses immune suppressing-independent functions. We found that HLA-G expressing BeWo choriocarcinoma cells increased cell-cell fusion compared to control BeWo cells under forskolin treatment. Regardless of forskolin treatment, the expression of fusogenic gene mRNAs, including syncytin-1, the transcription factor glial cell missing 1 (Gcm1), and beta human chorionic gonadotropin (β-hCG) were elevated. HLA-G up-regulates β-hCG production in human choriocarcinoma cells because HLA-G knockdown in JEG-3 cells induces a dramatic decrease in β-hCG compared with control cells. The defect in β-hCG production in HLA-G knocked-down cells could not be completely overcome by stimulating hCG production through increasing intracellular cAMP levels. HLA-G expressing cells have increased phosphorylation levels for extracellular signal-regulated kinase1/2 (Erk1/2) in BeWo cells. The Erk1/2 pathway is inactivated after the inhibition of HLA-G expression in JEG-3 cells. Finally, Erk1/2 inhibition was able to suppress the increased hCG production induced by HLA-G expression. Together, these data suggest novel roles for HLA-G in regulating β-hCG production via the modulation of the Erk1/2 pathway and by inducing trophoblast cell fusion.

VEGF111b, a new member of VEGFxxxb isoforms and induced by mitomycin C, inhibits angiogenesis

Vascular endothelial growth factor (VEGF-A) stimulating angiogenesis is required for tumor growth and progression. The conventional VEGF-A isoforms have been considered as pro-angiogenic factors. Another family of VEGF-A isoforms generated by alternative splicing, termed VEGFxxxb isoforms, has anti-angiogenic property, exemplified by VEGF165b. Here, we identify a new number of VEGFxxx family-VEGF111b induced by mitomycin C, although not detected in mitomycin C-unexposed ovarian cancer cells. SKOV3 cells were transfected with pcDNA3.1 empty vector, pcDNA3.1-VEGF111b or pcDNA3.1-VEGF165b to collect conditioned mediums respectively. VEGF111b overexpression inhibits proliferation, migration and tube formation of endothelial cell by inhibiting VEGF-R2 phosphorylation and its downstream signaling, similar to VEGF165b but slightly lower than VEGF165b. The anti-angiogenic property depends on the six amino acids of exon 8b of the VEGFxxxb isoforms. Our results show that VEGF111b is a novel potent anti-angiogenic agent that can target the VEGF-R2 and its signaling pathway to inhibit ovarian tumor growth.

VEGF111b, a C-terminal splice variant of VEGF-A and induced by mitomycin C, inhibits ovarian cancer growth

BackgroundAlternative splicing of VEGF-A gives rise to two families – the pro-angiogenic VEGFxxx family and the anti-angiogenic VEGFxxxb family that differ by only six amino acids at their C-terminal end. The first verified and widely reported VEGFxxxb family member is VEGF165b, and here VEGF165b is a positive control.MethordsVEGF111b mRNA was detected in ovarian cancer cell lines SKOV3 and OVCAR3 by RT-PCR. Western blot was used to detect VEGF111b and VEGF165b protein in the CMs and lysates of OVCAR3 cells. MTT and colony formation assay were used to detect the short-term and long-term proliferation inhibition ability of ovarian cancer cells with VEGF111b overexpression. Cell-cycle analysis was performed to further characterize VEGF111b inhibition effects. VEGF111b signaling on ovarian cancer cells were determined by western blot. The expression levels of Ki67, PCNA, CD31 and VEGF in VEGF111b overexpression xenograft model were detected by immunohistochemistry.ResultsUnder the effect of mitomycin C, we identify a new member of VEGFxxxb family-VEGF111b in ovarian cancer cell lines. SKOV3 and OVCAR cells were transfected with empty lentivirus, VEGF111b or VEGF165b lentivirus. VEGF111b and VEGF165b overexpression inhibits proliferation of the ovarian cancer cells, but inhibition effect of VEGF111b is slightly less efficient than VEGF165b. Cell cycle analysis was further used to elucidate the mechanism involved in the inhibition effect. Further, we detected the expression of VEGF-R2 in SKOV3 and OVCAR3 cells, and shown that VEGF111b might bind to conventional VEGF-R2 with the results of reducing VEGF-R2 tyrosine phosphorylation and downstream signaling to have anti-tumor effects. In vivo VEGF111b overexpression inhibits ovarian cancer growth in xenograft mice.ConclusionOur results show that VEGF111b, as a new member of VEGFxxxb family, with similar properties to VEGF165b, plays potent anti-tumor effect in vitro and in vivo that can target the VEGF-R2 and its signaling pathway to inhibit ovarian tumor growth. This also opens a new avenue for treating ovarian cancer.

Ovarian stimulation retards postimplantation development and alters global gene expression profile of blastocysts in mouse.

This study compares the quality, developmental capacity and global gene expression profile of embryos generated from superovulated and natural cycles. We found that ovarian stimulation impaired quality of blastocysts (cell number: 68.9 +/- 6.9 vs. 76.8 +/- 7.9; diameter of blastocysts: 145.3 +/- 76.9 microm vs. 152.6 +/- 65.5 microm), fetus development (rate of development to term: 45.5% vs. 69.1%; weight of 18.5-dpc fetuses: 1.23 +/- 0.03 g vs. 1.34 +/- 0.03 g) and caused 92 genes differentially expressed.

A meta-analysis of the impact of human leukocyte antigen-G on the outcomes of IVF/ICSI

This analysis was performed to determine whether the presence of soluble human leukocyte antigen-G (sHLA-G) in embryo culture medium is predictive of clinical outcomes in IVF treatment. The outcomes of implantation, clinical pregnancy, multiple pregnancy and miscarriage, between groups with and without sHLA-G in embryo culture media, were analysed. Fifteen studies with a total of 6170 cases were included. Ten of them were prospective studies while five were retrospective studies. Embryo culture media with sHLA-G were associated with significantly higher implantation rate and clinical pregnancy rate when compared with those without; the odd ratios (ORs) were 2.66 [95% confidence interval (CI): 1.75-4.06, P < 0.00001], 3.79 (95% CI: 2.69-5.33, P < 0.00001), respectively. There was no significant difference in the rate of multiple pregnancy (OR: 1.87, 95% CI: 0.55-6.31) and miscarriage (OR: 0.77, 95% CI: 0.52-1.16). The results suggested that the presence of sHLA-G in the embryo culture medium favoured higher implantation rate and pregnancy rate. However, the conclusion needs to be consolidated by further clinical studies using a more precise method of determination of sHLA-G and research on the physiological and molecular mechanisms of the beneficial effect of sHLA-G on early embryo development and implantation.

Age-related changes in the mitochondria of human mural granulosa cells

STUDY QUESTION What changes in the mitochondria of human mural granulosa cells (mGCs) with maternal aging? SUMMARY ANSWER The mitochondrial membrane potential (MMP) and the ability of oxidative phosphorylation (OXPHOS) of mGCs declines with reproductive aging, accompanied with more abnormal mitochondria. WHAT IS KNOWN ALREADY Mitochondria play an important role in the dialogue between the mGCs and oocytes. However, the underlying mechanism of mitochondrial dysfunction in mGCs in aging is still poorly understood. STUDY DESIGN SIZE, DURATION In total, 149 infertile women underwent IVF in the ART Centre of the Chinese PLA General Hospital, China from September 2016 to May 2017. Two age groups were investigated: the young group (<38 years old) and the old group (≥38 years old). PARTICIPANTS/MATERIALS, SETTING, METHODS The mitochondrial ultrastructure of mGCs was observed by transmission electron microscopy, and real-time quantitative polymerase chain reaction was applied to quantify the mitochondrial DNA (mtDNA) copy number, 4977-bp deleted DNA and mRNA expression of mitochondrial ATP synthases ATP5A1 and ATP5I. MMP was detected by flow cytometry and fluorescence microscopy, respectively. Reactive oxygen species (ROS) was tested by flow cytometry. A luminometer was used to measure the ATP levels and western blot to analyse the OXPHOS complex. MAIN RESULTS AND THE ROLE OF CHANCE In the young group, mitochondria were mostly round or oval, with a few intact parallel tubular-vesicular cristae and homogenous matrix density, while elongated mitochondria were mainly observed in the old group, which had numerous cristae and more high-density matrix particles. Abnormal mitochondria were more common in aging women (P = 0.012). mtDNA relative copy number was positively correlated with maternal age (r = 0.294, P = 0.009) and we found no one with 4977-bp deleted mitochondria. JC-1 (dye used as an indicator of MMP) ratio in the old group was significantly lower than the young group (3.01 ± 0.21 vs 3.85 ± 0.27, P = 0.033). Intracellular ROS levels between the groups did not differ significantly (P = 0.191). The intracellular ATP level in the young group was 1.75-fold higher than that of the advanced-age group (7.17 ± 1.16 vs 4.15 ± 0.60, P = 0.025). The protein expression of ATP5A1, as one of five proteins of OXPHOS, decreased with aging (P < 0.001). ATP5A1 mRNA expression was negatively correlated with aging (r = -0.341, P = 0.012). LIMITATIONS REASONS FOR CAUTION The quantity of mGCs from some individual patient, especially an advanced-age individual, was small, which cannot meet the demands of all the detections. WIDER IMPLICATIONS OF THE FINDINGS mGCs dysfunction with aging is mainly linked to impaired mitochondrial function, especially OXPHOS function. Improving the OXPHOS ability in mGCs should be the focus in resolving infertility among advanced age women and making mGCs the proper mitochondria donor cells in the autologous mitochondria transplantation to oocytes. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the grants of the National High Technology Research and Development Program of China, 863 Program No. SS2015AA020402, and the Key Projects of Military Medical Research, No. BWS11J058. There were no competing interests.

Interleukin‐6 regulates expression of Fos and Jun genes to affect the development of mouse preimplantation embryos

We investigated whether recombinant mouse interleukin‐6 (IL‐6) affects the development of preimplantation embryos and induces the ‐signal transducers and activators of transcription (JAK–STAT) signaling pathway by binding IL‐6 signal transducer (IL‐6st) and regulating Fos and Jun gene expression, thereby accounting for the negative effect of superovulation on embryo development.

De Novo Paternal FBN1 Mutation Detected in Embryos Before Implantation.

Background Marfan syndrome (MFS) is an autosomal dominant disease caused by mutations in the Fibrillin (FBN)1 gene and characterized by disorders in the cardiovascular, skeletal, and visual systems. The diversity of mutations and phenotypic heterogeneity of MFS make prenatal molecular diagnoses difficult. In this study, we used pre-implantation genetic diagnosis (PGD) to identify the pathogenic mutation in a male patient with MFS and to determine whether his offspring would be free of the disease. Material/Methods The history and pedigree of the proband were analyzed. Mutation analysis was performed on the couple and immediate family members. The couple chose IVF treatment and 4 blastocysts were biopsied. PGD was carried out by targeted high-throughput sequencing of the FBN1 gene in the embryos, along with single-nucleotide polymorphism haplotyping. Sanger sequencing was used to confirm the causative mutation. Results c.2647T>C (p.Trp883Arg) was identified as the de novo likely pathogenic mutation in the proband. Whole-genome amplification and sequencing of the 3 embryos revealed that they did not carry the mutation, and 1 blastocyst was transferred back to the uterus. The amniocentesis test result analyzed by Sanger sequencing confirmed the PGD. A premature but healthy infant free of heart malformations was born. Conclusions The de novo mutation c.2647T>C (p.Trp883Arg) in FBN1 was identified in a Chinese patient with MFS. Embryos without the mutation were identified by PGD and resulted in a successful pregnancy.