Establishment of human-embryonic-stem-cell line from mosaic trisomy 9 embryo

Functional assessment of donated human embryos for the generation of pluripotent embryonic stem cell lines

RESEARCH QUESTION

Can discarded embryos at blastocyst stage, donated to research because of genetic abnormalities and poor morphological quality, become a reliable source of human embryonic stem cell (HESC) lines?

DESIGN

This study was consecutively conducted with 23 discarded embryos that were donated to research between February 2020 and April 2021. All embryos, except one, were morphologically evaluated and underwent trophectoderm biopsy for preimplantation genetic testing using next-generation sequencing (NGS), and then vitrified. After warming, the embryos were placed in appropriate culture conditions for the generation of HESCs, which was functionally assessed with immunofluorescence and flow cytometry for pluripotency capacity and spontaneous in-vitro differentiation. Cytogenetic assessment of the HESC was conducted with multiplex ligation-dependent probe amplification, and micro array comparative genomic hybridization.

RESULTS

From the 23 embryos initially included, 17 survived warming, and 16 of them presented viability. Overall, the embryos presented poor morphological quality after warming. Only the previously untested embryo was capable of generating a new HESC line. Further characterization of this line revealed fully functional, euploid HESCs with preserved pluripotency, becoming a useful resource for research into human development and therapeutic investigation.

CONCLUSIONS

None of the donated blastocysts with poor morphological quality in association with genetic abnormalities detected by NGS had the capacity for further in-vitro expansion to originate pluripotent HESC lines. This finding seems to provide extra support to genetic counselling on the suitability of this type of embryo for clinical use.

Detection of maternal uniparental disomy 9 in association with low-level mosaic trisomy 9 at amniocentesis in a pregnancy associated with intrauterine growth restriction, abnormal first-trimester screening result (low PAPP-A and low PlGF), maternal preeclampsia and a favorable outcome

OBJECTIVE

We present detection of maternal uniparental disomy (UPD) 9 in association with low-level mosaic trisomy 9 at amniocentesis in a pregnancy associated with intrauterine growth restriction (IUGR), an abnormal first-trimester maternal serum screening result, abnormal non-invasive prenatal testing (NIPT), maternal preeclampsia and a favorable outcome.

CASE REPORT

A 37-year-old, primigravid woman underwent first-trimester maternal serum screening and NIPT at 11 weeks of gestation, which revealed a gene dosage increase in chromosome 9 and low levels of plasma protein-A (PAPP-A) and placental growth factor (PlGF) in maternal blood. The woman underwent amniocentesis at 16 weeks of gestation, which revealed a karyotype of 47,XX,+9[4]/46,XX[35] in cultured amniocytes. Simultaneous array comparative genomic hybridization (aCGH) analysis on uncultured amniocytes revealed a result of arr [GRCh37] (9) × 3 [0.14] (X) × 2, compatible with mosaic trisomy 9. The parental karyotypes were normal. Repeat amniocentesis was performed at 20 weeks of gestation. The cultured amniocytes had a karyotype of 47,XX,+9[1]/46,XX[23]. The uncultured amniocytes had a mosaic trisomy 9 level of 10.7% (12/112 cells) by interphase fluorescence in situ hybridization (FISH), a mosaic trisomy 9 level of 10-14% (log₂ ratio = 0.1) by aCGH, and maternal uniparental isodisomy 9 by polymorphic DNA marker analysis. Prenatal ultrasound revealed IUGR, and the mother had preeclampsia. At 29 weeks of gestation, a 1054-g phenotypically normal baby was delivered because of preterm labor. The cord blood and umbilical cord had the karyotype of 46, XX and maternal UPD 9 and isodisomy 9, while the placenta had trisomy 9 of maternal origin. Postnatal FISH anlaysis on 101 buccal mucosal cells and 100 urinary cells at age three months detected no trisomy 9 signals. The baby was doing well at age six months.

CONCLUSION

Pregnancy with low-level mosaic trisomy 9 and maternal UPD 9 at amniocentesis can be associated with IUGR, maternal preeclampsia and a favorable outcome. Fetuses with maternal UPD 9 can be associated with an abnormal NIPT result concerning chromosome 9, an abnormal first-trimester maternal serum screening result (low PAPP-A and low PlGF) and mosaic trisomy 9 at amniocentesis.

17β-Oestradiol promotes differentiation of human embryonic stem cells into dopamine neurons via cross-talk between insulin-like growth factors-1 and oestrogen receptor β

Human embryonic stem cells (hESCs) can self‐renew and differentiate into all cell lineages. E2 is known to exhibit positive effects on embryo development. Although the importance of E2 in many physiological processes has been reported, to date few researchers have investigated the effects of E2 on hESCs differentiation. We studied the effects of E2 on dopamine (DA) neuron induction of hESCs and its related signalling pathways using the three‐stage protocol. In our study, 0.1 μM E2 were applied to hESCs‐derived human embryoid bodies (hEBs) and effects of E2 on neural cells differentiation were investigated. Protein and mRNA level assay indicated that E2 up‐regulated the expression of insulin‐like growth factors (IGF)‐1, ectoderm, neural precursor cells (NPC) and DA neuron markers, respectively. The population of hESC‐derived NPCs and DA neurons was increased to 92% and 93% to that of DMSO group, respectively. Furthermore, yield of DA neuron‐secreted tyrosine hydroxylase (TH) and dopamine was also increased. E2‐caused promotion was relieved in single inhibitor (ICI or JB1) group partly, and E2 effects were repressed more stronger in inhibitors combination (ICI plus JB1) group than in single inhibitor group at hEBs, hNPCs and hDA neurons stages. Owing to oestrogen receptors regulate multiple brain functions, when single or two inhibitors were used to treat neural differentiation stage, we found that oestrogen receptor (ER)β but not ERα is strongly repressed at the hNPCs and hDA neurons stage. These findings, for the first time, demonstrate the molecular cascade and related cell biology events involved in E2‐improved hNPC and hDA neuron differentiation through cross‐talk between IGF‐1 and ERβ in vitro.