O-062 MicroRNAs in Blastocoel Fluid: a molecular signature for predicting human embryo implantation potential

Study question

Can microRNA expression in blastocoel fluid (BF) predict embryo implantation potential?

Summary answer

Up-regulation of miR-106, miR-373, miR-301, miR-320 and miR-525-3p represents the molecular signature characterizing the embryos with high implantation capability.

What is known already

The discovery of DNA within the BF and in spent embryo culture media, has caused increased interest in the non-invasive preimplantation testing application for monogenic disorders and aneuploidies. Aneuploid embryos have a lower implantation potential, however, chromosomal abnormalities represent only a tiny percentage of the causes of implantation failure. MiRNAs can control all cellular pathways and are involved in pluripotency, self-renewal, and stemness, and their altered regulation affects different human diseases.

Study design, size, duration

From September 2018 to March 2022, 112 BFsampleswere collected from human embryos on the fifth day of development, before the blastocyst cryopreservation. The samples were classified according to blastocyst grade and the data on implantation outcome and term births were collected for the transferred embryos. We compared the expression profiles of 89 miRNAs, previously identified in BF, between 33 BF from implanted embryos and 30 from non-implanted ones, regardless of blastocyst grade.

Participants/materials, setting, methods

By custom-designed TaqMan Low-Density Array card (TLDA), we analyzed the expression of 89 miRNAs in 4 different BF samples simultaneously. Differentially expressed (DE) miRNAs were identified by Volcano plot and Significance Analysis of Microarrays (SAM) tests. Bioinformatic analysis was performed to identify the biological role of the DE miRNAs. To evaluate miRNA’s ability for predicting implantation, Pearson’s correlation analyses, classical univariate Receiver Operator Characteristic (ROC) curve analysis, and the optimal cut-off value determination were performed.

Main results and the role of chance

We found five miRNAs, miR-106, miR-373, miR-301, miR-320 and miR-525-3pup-regulated in BF from implanted blastocysts. The identified miRNAs perform an important role during the first phases of embryo development suggesting that their up-regulation may reflect embryo health. Moreover, four of the five miRNAs showed significant correlation coefficients in both implanted and non-implanted blastocysts, indicating that their expression changes in the same way in the single sample and reflects the potentiality of the embryo to implant. Finally, ROC curve analysis confirmed that our miRNAs could be considered potential biomarkers for implantation.

Limitations, reasons for caution

Successful implantation requires a close dialogue between the embryo and the endometrium, mediated by different proteins and miRNAs produced by both the embryo and maternal tissues. Determining the quality of the embryo and its implantation potential is not sufficient to predict successful pregnancy outcomes.

Wider implications of the findings

This study represents the first report correlating miRNA profiles in BFand implantation and suggests that miRNA signature could become an accurate tool to evaluate embryo quality. It could be associated or replaced with the PGT-A to choose the most competent embryo and improve the outcome of assisted reproduction cycles.

Trial registration number

The study has been approved by theEthical Committee of Azienda Ospedaliero Universitaria Policlinico "G.Rodolico -San Marco" Catania.

P-064 MicroRNAs as potential biomarkers for male infertility related to Testicular Germ Cell Tumors

Study question

Could microRNAs represent efficient biomarkers to evaluate male infertility and the tendency of develop testicular germ cell tumors (TGCTs)?

Summary answer

The up-regulation of miR-193a-5p, miR-93-5p and let-7c-5p in TGCT patients with impaired spermiogram could represent a molecular signature of male infertility related to TGCTs.

What is known already

Testicular germ cell tumors (TGCTs) are the most recurrent tumors in young men with the highest incidence between the ages of 20 and 40 years and represent more than 60% of all cancers diagnosed in this age range. Several studies have shown a correlation between TGCTs and infertility, not only because infertility could be a consequence of testicular damage due to TGCTs but also because infertility may represent a risk factor for TGCTs. Therefore, it is important to find valid biomarkers that could be used to specifically identify infertility related to an increased risk of developing TGCTs.

Study design, size, duration

From March 2021 to January 2023, we collected 44 seminal plasma samples: 17 from TGCT patients who were undergoing sperm cryopreservation prior to chemotherapy, 14 with impaired spermiogram (IS) and 3 with normal spermiogram (NS) and 27 from control patients, 16 with IS and 11 with NS, undergoing assisted fertilization techniques. We evaluated the potential role of miRNAs as non-invasive biomarkers, analyzing the differential expression of 84 miRNAs in relation to cancer, infertility and both.

Participants/materials, setting, methods

Semen samples were placed 30’/37 °C, seminal plasma was purified using density-gradient centrifugation and stored at -80 °C. RNA was purified by Qiagen miRNeasy Serum/Plasma Kit and analyzed by miRCURY LNA miRNA SYBR®Green PCR_SerumPlasma, 96-well plate. We applied the 2−ΔΔCT method and statistical significance was evaluated by Significance Analysis of Microarrays, screened by p-values ≤ 0.05. We performed a Pearson correlation analysis applying two-sided p-values. miRTarBASE, MIENTURNET and Cytoscape were used for bioinformatics analysis.

Main results and the role of chance

In the four comparisons, we found 9 differentially expressed microRNAs. In particular, miR-221-3p, miR-222-3p, miR-204-5p and miR-205-5p down regulation would appear to be related to infertility, regardless to the cancer. Conversely, all TGCT patients shown an up-regulation of miR-376c-3p. Interestingly, up-regulation of miR-193a-5p, miR-93-5p and let-7c-5p specifically discriminates the infertile cancer patients vs other categories. Moreover, these three miRNAs showed a significant positive correlation both in cancer patients with impaired spermiogram and in infertile controls. This correlation demonstrates that their expression changes in the same way in the single samples and strongly suggests their role as early biomarkers of TGCT patients with impaired spermiogram. From the KEGG pathway analysis has emerged that DE miRNAs are involved in several signaling pathway, such as MAPK, mTOR, p53, PI3K-Akt, AMPK, FoxO, JAK-STAT, Ras, Estrogen signaling pathways, as well as cell cycle and cellular senescence. Moreover, from the Diseases Ontology analysis we found than those miRNAs are involved in germ cell tumor, male reproductive organ cancer, prostate cancer, male infertility and azoospermia.

Limitations, reasons for caution

The data must be validated by single assays in higher number of samples. These experiments are currently ongoing.

Wider implications of the findings

Three of the DE miRNAs are overexpressed in TGCT with impaired spermiogram patients. Specifically, they are over-expressed in TGCT with impaired spermiogram compared to infertile controls, so they may represent specific biomarkers able to discriminate, among the young men with infertility, those with higher risk of develop testicular cancer.

Trial registration number

Not applicable

Identification of extracellular vesicles and characterization of miRNA expression profiles in human blastocoel fluid

In this study, for the first time, we demonstrated the presence of microRNAs and extracellular vesicles in human blastocoel fluid. The bioinformatic and comparative analyses identified the biological function of blastocoel fluid microRNAs and suggested a potential role inside the human blastocyst. We found 89 microRNAs, expressed at different levels, able to regulate critical signaling pathways controlling embryo development, such as pluripotency, cell reprogramming, epigenetic modifications, intercellular communication, cell adhesion and cell fate. Blastocoel fluid microRNAs reflect the miRNome of embryonic cells and their presence, associated with the discovery of extracellular vesicles, inside blastocoel fluid, strongly suggests their important role in mediating cell communication among blastocyst cells. Their characterization is important to better understand the earliest stages of embryogenesis and the complex circuits regulating pluripotency. Moreover, blastocoel fluid microRNA profiles could be influenced by blastocyst quality, therefore, microRNAs might be used to assess embryo potential in IVF cycles.

Expression analysis of TFIID in single human oocytes: new potential molecular markers of oocyte quality

Molecular characterization of human female gametes should make it easier to understand the basis of certain infertility disorders. Biologically significant mRNAs have been analysed in single oocytes to search for molecular biomarkers of oocyte quality. Initial analysis was focused on mRNA for proteins involved in cell growth and cycle control, specifically those encoding members of the general transcription apparatus such as the subunits of the general transcription factor TFIID. This heteromultimeric protein, comprising about 15 subunits, is the most important general transcription factor of the second class. These proteins are essential for the initiation of transcription of protein-coding genes, so they must be present in mature oocytes for mRNA synthesis during the first phases of embryonic development. Semi-quantitative reverse transcriptionpolymerase chain reaction was used to identify different TFIID subunits in single oocytes and to search for differences in expression as compared with control tissues. The data show that the mRNAs for most TFIID subunits are indeed synthesized in oocytes, but their expression profiles differ markedly. TATAbox-binding protein associated factor 4B (TAF4B), TAF5 and TATAbox-binding protein-like 2 (TBPL2) are expressed at higher levels in oocytes than in control tissues. It is suggested that they could be used as biomarkers of oocyte quality.

Transverse and longitudinal scaling laws in non-homogeneous low Re turbulence

The statistical properties of the velocity fluctuation components at moderate Reλ are studied in homogeneous and non-homogeneous turbulence by an experimental technique. Measurements are performed by means of a hot-wire anemometer with X-probe downstream of a screen for several positions, x/M=9 up to 109, where M is the screen mesh size, with Reλ ranging from 37 to 82. The homogeneity of the flow is analyzed by means of velocity measurements in different transverse positions and a direct evaluation of the local isotropy of the flow is performed by means of velocity spectra. The scaling properties of the statistical moments of the structure functions up to the order of six, are investigated in the extreme positions by means of the extended self-similarity (ESS) method and the intermittency exponents are detected for both homogeneous and non-homogeneous flow conditions. A comparison of the longitudinal and transverse intermittency exponents as functions of the position is then performed and discussed in addition to the analysis of the transition from the anomalous to a regular scaling for small spatial separation.