Infertility diagnosis has a significant impact on the transcriptome of developing blastocysts

STUDY QUESTION: Is the human blastocyst transcriptome associated with infertility diagnosis, specifically: polycystic ovaries (PCO), male factor (MF) and unexplained (UE)? SUMMARY ANSWER: The global blastocyst transcriptome was significantly altered in association with a PCO, MF and UE infertility diagnosis. WHAT IS KNOWN ALREADY: Infertility diagnosis has an impact on the probability for a successful outcome following an IVF cycle. Limited information is known regarding the relationship between a specific infertility diagnosis and blastocyst transcription during preimplantation development. STUDY DESIGN, SIZE, DURATION: Blastocysts created during infertility treatment from patients with specific infertility diagnoses (PCO, MF and UE) were analyzed for global transcriptome compared to fertile donor oocyte blastocysts (control). PARTICIPANTS/MATERIALS, SETTING, METHODS: Surplus cryopreserved blastocysts were donated with patient consent and institutional review board approval. Female patients were <38 years old with male patients <40 years old. Blastocysts were grouped according to infertility diagnosis: PCO (n = 50), MF (n = 50), UE (n = 50) and fertile donor oocyte controls (n = 50). Pooled blastocysts were lysed for RNA isolation followed by microarray analysis using the SurePrint G3 Human Gene Expression Microarray. Validation was performed on significant genes of interest using real-time quantitative PCR (RT-qPCR). MAIN RESULTS AND THE ROLE OF CHANCE: Transcription alterations were observed for all infertility etiologies compared to controls, resulting in differentially expressed genes: PCO = 869, MF = 348 and UE = 473 (P 2-fold). Functional annotation of biological and molecular processes revealed both similarities, as well as differences, across the infertility groups. All infertility etiologies displayed transcriptome alterations in signal transducer activity, receptor binding, reproduction, cell adhesion and response to stimulus. Blastocysts from PCO patients were also enriched for apoptotic genes while MF blastocysts displayed enrichment for genes involved in cancer processes. Blastocysts from couples with unexplained infertility displayed transcription alterations related to various disease states, which included mechanistic target of rapamycin (mTOR) and adipocytokine signaling. RT-qPCR validation confirmed differential gene expression for the following genes: BCL2 like 10 (BCL2L10), heat shock protein family A member 1A (HSPA1A), heat shock protein family A member 1B (HSPA1B), activating transcription factor 3 (ATF3), fibroblast growth factor 9 (FGF9), left-right determination factor 1 (LEFTY1), left-right determination factor 2 (LEFTY2), growth differentiation factor 15 (GDF15), inhibin beta A subunit (INHBA), adherins junctions associated protein 1 (AJAP1), cadherin 9 (CDH9) and laminin subunit alpha 4 (LAMA4) (P 2-fold)

Compromised global embryonic transcriptome associated with advanced maternal age

Purpose To investigate the global transcriptome and associated embryonic molecular networks impacted with advanced maternal age (AMA). Methods Blastocysts derived from donor oocyte IVF cycles with no male factor infertility (< 30 years of age) and AMA blastocysts (≥ 42 years) with no other significant female factor infertility or male factor infertility were collected with informed patient consent. RNA sequencing libraries were prepared using the SMARTer® Ultra® Low Kit (Clontech Laboratories) and sequenced on the Illumina HiSEQ 4000. Bioinformatics included Ingenuity® Pathway Analysis (Qiagen) with ViiA™7 qPCR utilized for gene expression validation (Applied Biosystems). Results A total of 2688 significant differentially expressed transcripts were identified to distinguish the AMA blastocysts from young, donor controls. 2551 (95%) of these displayed decreased transcription in the blastocysts from older women. Pathway analysis revealed three altered molecular signaling networks known to be critical for embryo and fetal development: CREBBP, ESR1, and SP1. Validation of genes within these networks confirmed the global decreased transcription observed in AMA blastocysts (P < 0.05). Conclusions A significant, overall decreased global transcriptome was observed in blastocysts from AMA women. The ESR1/SP1/CREBBP pathway, in particular, was found to be a highly significant upstream regulator impacting biological processes that are vital during embryonic patterning and pre-implantation development. These results provide evidence that AMA embryos are compromised on a cell signaling level which can repress the embryo’s ability to proliferate and implant, contributing to a deterioration of reproductive outcomes

The impact of infertility diagnosis on embryo-endometrial dialogue

Initial stages of implantation involve bi-directional molecular crosstalk between the blastocyst and endometrium. This study investigated an association between infertility etiologies, specifically advanced maternal age (AMA) and endometriosis, on the embryo-endometrial molecular dialogue prior to implantation. Co-culture experiments were performed with endometrial epithelial cells (EEC) and cryopreserved day 5 blastocysts (n?=?41???Grade 3BB) donated from patients presenting with AMA or endometriosis, compared to fertile donor oocyte controls. Extracellular vesicles isolated from co-culture supernatant were analyzed for miRNA expression and revealed significant alterations correlating to AMA or endometriosis. Specifically, AMA resulted in 16 miRNAs with increased expression (P???0.05) and strong evidence for negative regulation toward 206 target genes. VEGFA, a known activator of cell adhesion, displayed decreased expression (P???0.05), validating negative regulation by 4 of these increased miRNAs: miR-126; 150; 29a; 29b (P???0.05). In endometriosis patients, a total of 10 significantly altered miRNAs displayed increased expression compared to controls (miR-7b; 9; 24; 34b; 106a; 191; 200b; 200c; 342-3p; 484) (P???0.05), targeting 1014 strong evidence-based genes. Three target genes of miR-106a (CDKN1A, E2F1 and RUNX1) were independently validated. Functional annotation analysis of miRNA-target genes revealed enriched pathways for both infertility etiologies, including disrupted cell cycle regulation and proliferation (P???0.05). These extracellular vesicle-bound secreted miRNAs are key transcriptional regulators in embryo-endometrial dialogue and may be prospective biomarkers of implantation success. One of the limitations of this study is that it was a stimulated, in vitro model and therefore may not accurately reflect the in-vivo environment

Epigenetic Dysregulation Observed in Monosomy Blastocysts Further Compromises Developmental Potential.

Epigenetic mechanisms such as DNA methylation regulate genomic imprinting and account for the distinct non-equivalence of the parental genomes in the embryo. Chromosomal aneuploidy, a major cause of infertility, distorts this highly regulated disparity by the presence or absence of chromosomes. The implantation potential of monosomy embryos is negligible compared to their trisomy counterparts, yet the cause for this is unknown. This study investigated the impact of chromosomal aneuploidy on strict epigenetically regulated domains, specifically imprinting control regions present on aneuploid chromosomes. Donated cryopreserved human IVF blastocysts of transferable quality, including trisomy 15, trisomy 11, monosomy 15, monosomy 11, and donor oocyte control blastocysts were examined individually for DNA methylation profiles by bisulfite mutagenesis and sequencing analysis of two maternally methylated imprinting control regions (ICRs), SNRPN (15q11.2) and KCNQ1OT1 (11p15.5), and one paternally methylated imprinting control region, H19 (11p15.5). Imprinted genes within the regions were also evaluated for transcript abundance by RT-qPCR. Overall, statistically significant hypermethylated and hypomethylated ICRs were found in both the trisomy and monosomy blastocysts compared to controls, restricted only to the chromosome affected by the aneuploidy. Increased expression was observed for maternally-expressed imprinted genes in trisomy blastocysts, while a decreased expression was observed for both maternally- and paternally-expressed imprinted genes in monosomy blastocysts. This epigenetic dysregulation and altered monoallelic expression observed at imprinting control regions in aneuploid IVF embryos supports euploid embryo transfer during infertility treatments, and may specifically highlight an explanation for the compromised implantation potential in monosomy embryos

Corona cell RNA sequencing from individual oocytes revealed transcripts and pathways linked to euploid oocyte competence and live birth.

Corona cells surround the oocyte and maintain a close relationship through transzonal processes and gap junctions, and may be used to assess oocyte competence. In this study, the corona cell transcriptome of individual cumulus oocyte complexes (COCs) was investigated. Isolated corona cells were collected from COCs that developed into euploid blastocysts and were transferred in a subsequent frozen embryo transfer. Ten corona cell samples underwent RNA-sequencing to generate unique gene expression profiles. Live birth was compared with negative implantation after the transfer of a euploid blastocyst using bioinformatics and statistical analysis. Individual corona cell samples produced a mean of 21.2 million sequence reads, and 307 differentially expressed transcrpits (P < 0.05; fold change ?2). Enriched pathway analysis showed Wnt signalling, mitogen-activated protein kinases signalling, focal adhesion and tricarboxylic acid cycle to be affected by implantation outcome. The Wnt/beta-catenin signalling pathway, including genes APC, AXIN and GSK3B, were independently validated by real-time quantitative reverse transcription. Individual, corona cell transcriptome was successfully generated using RNA-sequencing. Key genes and signalling pathways were identified in association with implantation outcome after the transfer of a euploid blastocyst in a frozen embryo transfer. These data could provide novel biomarkers for the non-invasive assessment of embryo viability