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Human blastocysts diagnosed using Next-generation Sequencing with mosaicism demonstrate distinct transcriptomic profiles compared to euploid or aneuploid embryos

ABSTRACT: Objective: To determine if embryos diagnosed as mosaic using Next-generation sequencing (NGS) have distinct gene expression profiles compared to embryos diagnosed as euploid or aneuploid. Materials and methods: Fifteen blastocysts were diagnosed as mosaic with NGS including 7 full mosaic monosomies, 5 partial mosaic monosomies, 2 full mosaic trisomies, and 1 partial mosaic trisomy. Three NGS diagnosed euploid embryos, and 25 aneuploid embryos (9 NGS, 14 aCGH, 2 Single Nucleotide Polymorphism array) were used as comparisons. Replicate samples were available for all euploid and full aneuploid embryos. Aneuploid embryos were chosen if their aneuploid chromosome corresponded with one of the mosaic embryos. Complementary DNA from the samples was created using the SMATer v4 Ultra Low Kit. RNA-seq library preparation followed by sequencing on the Illumina HiSeq 2500 with 50 nucleotide length paired end reads was performed. The STAR/2.5 aligner was used to align the reads against the hg19 ensemble reference transcriptome. Differentially expressed genes (DEGs) were calculated using DES-seq2/3.5, and p values <0.05 were considered significantly differentially expressed. Pathway analysis was performed on the top DEGs among all of the mosaic embryos with p<0.05 considered significant. Main results: The 15 mosaic embryos had transcriptomic profiles which were distinct from full aneuploid embryos involving the same chromosome. Mosaic embryos had fewer DEGs compared to aneuploid embryos of the same chromosome when using euploid embryos as controls. Mosaic embryos were grouped on principal component analysis (PCA) and distinguishable from euploid and aneuploid embryos. Pathways involving cell proliferation, differentiation, and apoptosis were the most disrupted from the presence of a mosaic cell line.

ORGANISM(S): Homo sapiens

PROVIDER: GSE151219 | GEO | 2020/05/27

REPOSITORIES: GEO

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Project description:Preimplantation genetic diagnosis (PGD) of aneuploidy by fluorescence in situ hybridisation (FISH) has not delivered the expected clinical benefit. Many previous re-analysis studies of embryos deemed aneuploid by FISH on day 3 have found a high degree of chromosomal normalcy at the blastocyst stage. While most have interpreted this as âself correction,â there remains a lack of evidence for such a phenomenon. A more comprehensive technique for 24 chromosome aneuploidy screening was utilised here to re-evaluate blastocysts previously diagnosed as abnormal by FISH and investigate possible self correction mechanisms, including extrusion or duplication of aneuploid chromosomes resulting in uniparental isodisomy (UPID), and preferential segregation of aneuploidy to the trophectoderm (TE). Embryos that developed to a morphologically normal blastocyst after an aneuploidy diagnosis by cleavage stage FISH were biopsed into 4 sections, 3 TE and 1 inner cell mass (ICM), and randomised for evaluation by single nucleotide polymorphism (SNP) microarray based 24 chromosome aneuploidy screening (MA-PGD). Fifty-eight percent of blastocysts were euploid for all 24 chromosomes despite an aneuploid FISH result on day 3. Only 18% were consistent with the original FISH diagnosis, while the remaining 24% identified abnormalities that were different from the original FISH diagnosis. Abnormalities did not preferentially segregate to the TE and aneuploid chromosome extrusion or duplication resulting in UPID did not occur. Cleavage stage FISH is poorly predictive of aneuploidy in an embryo that develops into a morphologically normal blastocyst. Clinicians should consider re-evaluating embryos diagnosed as aneuploid by FISH that form morphologically normal blastocysts using a validated comprehensive 24 chromosome aneuploidy screening method. Affymetrix SNP arrays were processed according to the manufacturer's directions on DNA extracted from 50 cryopreserved blastocysts that were biopsied into 3 sections of trophectoderm and 1 inner cell mass section. Affymetrix SNP array analysis was successfully completed on 145 trophectoderm samples and 47 ICM samples from embryos, 8 lymphocyte samples from cell lines and 6 mixed male and female samples.

Project description:Study question: Could extracellular vesicles (EVs) secreted by aneuploid embryos a) serve for development of RNA biomarkers for preimplantation genetic testing for aneuploidy (PGT-A) and b) elicit a relevant transcriptomic response in decidualised primary endometrial stromal cells (dESCs)? Summary answer: Aneuploid embryo EVs a) contain genes PPM1J, LINC00561, ANKRD34C and TMED10 in differential abundance from euploid EVs and b) induce up-regulation of MUC1 transcript in dESCs. What is known already: PGT-A is popular as it is thought to facilitate transfer of euploid embryos to increase implantation probability but the technology is controversial, as it requires an invasive embryo biopsy with an elusive long-term biosafety. The development of non-invasive methods to screen out aneuploid embryos is paramount. It is also critical to decode the embryo-endometrial dialog underlying implantation failure. We have previously reported that IVF embryos secrete EVs that can be internalised by ESCs, conceptualising that successful implantation to the endometrium is facilitated by EVs, which may additionally serve as biomarkers of ploidy status. Study design, size, duration: Embryos destined for biopsy on days 5-7 for PGT-A were grown under standard conditions. Spent media (30μl) were collected from euploid (n=175) and aneuploid (n=140)embryos at cleavage (days 1-3) stage and from euploid (n=187) and aneuploid (n=142) embryos at blastocyst (days 3-5) stage. Media samples from n=35 cleavage embryos were pooled in order to obtain five euploid and four aneuploid pools. Similarly, media samples from blastocyst were pooled to create one euploid and one aneuploid pool. ESCs were obtained from five women undergoing diagnostic laparoscopy. Participants/materials, setting, methods: EVs were isolated from pools of media derived from euploid and aneuploid day 3 embryos with differential centrifugation and EV-RNA sequencing was performed following the SMARTer Stranded Total RNA-Seq approach. ESCs were decidualised (E2:10nM, P4:1uM, cAMP:0.5 mM twice every 48 hours) and treated for 24 hours with 50 ng/ml euploid or aneuploid EVs extracted from blastocyst media. RNA sequencing was performed on ESCs following the Illumina Truseq RNAseq protocol. Main results and the role of chance: Aneuploid cleavage stage embryos secreted EVs that were less abundant in RNA fragments originating from the genes PPM1J (log2fc=-5.13, p=0.011), LINC00561 (log2fc=-7.87, p=0.010) and ANKRD34C (log2fc=-7.30, p=0.017) and more abundant in TMED10 (log2fc=1.63 p=0.025) compared to EVs from euploid embryos. Decidualisation per se induced downregulation of MUC1 (log2FC=-0.54, p=0.0028) in ESCs as prerequisite for the establishment of receptive endometrium. The expression of MUC1 transcript in decidualised ESCs was significantly increased following treatment with aneuploid compared to euploid embryo-secreted EVs (log2FC=0.85, p=0.0201). Limitations, reasons for caution: The findings of the study may require validation utilising a second cohort of EVs samples. Wider implications of the findings: The discovery that the RNA cargo of EVs secreted from aneuploid cleavage stage embryos is diverse from that of euploid embryos potentiates the development of non-invasive methodology for PGT-A. The upregulation of MUC1 in dESCs following aneuploid embryo EV treatment proposes a new mechanism underlying implantation failure. Funding: The study was supported by a MSCA fellowship awarded to SM by the European Commission (CERVINO grant agreement ID: 79620) and by a BIRTH research grant from Theramex HQ UK Ltd

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Human blastocysts diagnosed using Next-generation Sequencing with mosaicism demonstrate distinct transcriptomic profiles compared to euploid or aneuploid embryos

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