Protein expression in human cumulus cells as an indicator of blastocyst formation and pregnancy success

Maturational competence of equine oocytes is associated with alterations in their 'cumulome'

Assisted reproductive technologies are an emerging field in equine reproduction, with species-dependent peculiarities, such as the low success rate of conventional IVF. Here, the 'cumulome' was related to the developmental capacity of its corresponding oocyte. Cumulus-oocyte complexes collected from slaughterhouse ovaries were individually matured, fertilized by ICSI, and cultured. After maturation, the cumulus was collected for proteomics analysis using label-free mass spectrometry (MS)-based protein profiling by nano-HPLC MS/MS and metabolomics analysis by UPLC-nanoESI MS. Overall, a total of 1671 proteins and 612 metabolites were included in the quantifiable 'cumulome'. According to the development of the corresponding oocytes, three groups were compared with each other: not matured (NM; n = 18), cleaved (CV; n = 15), and blastocyst (BL; n = 19). CV and BL were also analyzed together as the matured group (M; n = 34). The dataset revealed a closer connection within the two M groups and a more distinct separation from the NM group. Overrepresentation analysis detected enrichments related to energy metabolism as well as vesicular transport in the M group. Functional enrichment analysis found only the KEGG pathway 'oxidative phosphorylation' as significantly enriched in the NM group. A compound attributed to ATP was observed with significantly higher concentrations in the BL group compared with the NM group. Finally, in the NM group, proteins related to degradation of glycosaminoglycans were lower and components of cumulus extracellular matrix were higher compared to the other groups. In summary, the study revealed novel pathways associated with the maturational and developmental competence of oocytes.

Nonerythroid hemoglobin promotes human cumulus cell viability and the developmental capacity of the human oocyte

OBJECTIVE

To determine the relationship between the levels of cumulus cell (CC) hemoglobin messenger ribonucleic acid (mRNA) and the developmental potential of the associated oocyte and whether hemoglobin protects the CCs from oxidative stress-induced apoptosis.

DESIGN

Laboratory-based study.

SETTING

University laboratory and university-affiliated in vitro fertilization center.

PATIENT(S)

Cumulus cells from the oocytes of patients who underwent in vitro fertilization with intracytoplasmic sperm injection with and without preimplantation genetic testing between 2018 and 2020.

INTERVENTION(S)

Studies on individual and pooled CCs collected at the time of oocyte retrieval or cultured under 20% or 5% O2.

MAIN OUTCOME MEASURE(S)

Quantitative polymerase chain reaction analysis of individual and pooled patient CC samples were used to monitor the hemoglobin mRNA levels. Reverse transcription-polymerase chain reaction arrays were used to assess genes that regulate oxidative stress in CCs associated with aneuploid and euploid blastocysts. Studies were conducted to assess the effect of oxidative stress on the rate of apoptosis, level of reactive oxygen species, and gene expression in CCs in vitro.

RESULT(S)

Compared with CCs associated with arrested and aneuploid blastocysts, the mRNA levels encoding the alpha and beta chains of hemoglobin increased by 2.9- and 2.3-fold in CCs associated with euploid blastocysts, respectively. The mRNA levels encoding the alpha and beta chains of hemoglobin also increased by 3.8- and 4.5-fold in CCs cultured under 5% O2 vs. 20% O2, respectively, and multiple regulators of oxidative stress were overexpressed in cells cultured under 20% O2 compared with those under 5% O2. However, the rate of apoptosis and amount of mitochondrial reactive oxidative species increased by 1.25-fold in CCs cultured under 20% O2 compared with those under 5% O2. Variable amounts of the alpha and beta chains of hemoglobin were also detected within the zona pellucida and oocytes.

CONCLUSION(S)

Higher levels of nonerythroid hemoglobin in CCs are associated with oocytes that result in euploid blastocysts. Hemoglobin may protect CCs from oxidative stress-induced apoptosis, which may enhance cumulus-oocyte interactions. Moreover, CC-derived hemoglobin may be transferred to the oocytes and protect it from the adverse effects of oxidative stress that occurs in vivo and in vitro.

Extracellular cell-free RNA profile in human large follicles and small follicles

Background: Previous studies have shown that a large number of valuable and functional cell-free RNAs (cfRNAs) were found in follicular fluid. However, the species and characteristics of follicular fluid cfRNAs have not been reported. Furthermore, their implications are still barely understood in the evaluation of follicular fluid from follicles of different sizes, which warrants further studies.

Objective: This study investigated the landscape and characteristics of follicular fluid cfRNAs, the source of organization, and the potential for distinguishing between follicles of different sizes.

Methods: Twenty-four follicular fluid samples were collected from 20 patients who received in vitro fertilization (n = 9) or ICSI (n = 11), including 16 large follicular fluid and 8 small follicular fluid samples. Also, the cfRNA profile of follicular fluid samples was analyzed by RNA sequencing.

Results: This result indicated that the concentration of follicular fluid cfRNAs ranged from 0.78 to 8.76 ng/ml, and fragment length was 20–200 nucleotides. The concentration and fragment length of large follicular fluid and small follicular fluid samples were not significantly different (p > 0.05). The technical replica correlation of follicular fluid samples ranged from 0.3 to 0.9, and the correlation of small follicular fluid samples was remarkably (p < 0.001) lower than that of large follicular fluid samples. Moreover, this study found that cfRNAs of the follicular fluid could be divided into 37 Ensembl RNA biotypes, and a large number of mRNAs, circRNAs, and lncRNAs were observed in the follicular fluid. The number of cfRNAs in large follicular fluid was remarkably (p < 0.05) higher than that of small follicular fluid. Furthermore, the follicular fluid contained a large amount of intact mRNA and splice junctions and a large number of tissue-derived RNAs, which are at a balanced state of supply and elimination in the follicular fluid. KEGG pathway analysis showed that differentially expressed cfRNAs were enriched in several pathways, including thyroid hormone synthesis, the cGMP-PKG signaling pathway, and inflammatory mediator regulation of TRP channels. In addition, we further showed that four cfRNAs (TK2, AHDC1, PHF21A, and TTYH1) serve as a potential indicator to distinguish the follicles of different sizes. The ROC curve shows great potential to predict follicular fluid from follicles of different sizes [area under the curve (AUC) > 0.88].

Conclusion: Overall, our study revealed that a large number of cfRNAs could be detected in follicular fluid and could serve as a potential non-invasive biomarker in distinguishing between follicles of different sizes. These results may inform the study of the utility and implementation of cfRNAs in clinical practice.

Implementing a preimplantation proteomic approach to advance assisted reproduction technologies in the framework of predictive, preventive, and personalized medicine

The evolution of the field of assisted reproduction technology (ART) in the last 40 years has significantly contributed to the management of global infertility. Despite the great numbers of live births that have been achieved through ART, there is still potential for increasing the success rates. As a result, there is a need to create optimum conditions in order to increase ART efficacy. The selection of the best sperm, oocyte, and embryo, as well as the achievement of optimal endometrial receptivity, through the contribution of new diagnostic and treatment methods, based on a personalized proteomic approach, may assist in the attainment of this goal. Proteomics represent a powerful new technological development, which seeks for protein biomarkers in human tissues. These biomarkers may aid to predict the outcome, prevent failure, and monitor in a personalized manner in vitro fertilization (IVF) cycles. In this review, we will present data from studies that have been conducted in the search for such biomarkers in order to identify proteins related to good sperm, oocyte, and embryo quality, as well as optimal endometrial receptivity, which may later lead to greater results and the desirable ART outcome.

The Human Ovary and Future of Fertility Assessment in the Post-Genome Era

Proteomics has opened up new avenues in the field of gynecology in the post-genome era, making it possible to meet patient needs more effectively and improve their care. This mini-review aims to reveal the scope of proteomic applications through an overview of the technique and its applications in assisted procreation. Some of the latest technologies in this field are described in order to better understand the perspectives of its clinical applications. Proteomics seems destined for a promising future in gynecology, more particularly in relation to the ovary. Nevertheless, we know that reproductive biology proteomics is still in its infancy and major technical and ethical challenges must first be overcome.

Proteomics of reproduction: Prospects and perspectives

In recent years, proteomics has been used widely in reproductive research in order to understand the molecular mechanisms related to gametes at the cellular level and the role of proteins involved in fertilization. Network and pathway analysis using bioinformatic tools have paved way to obtain a wider picture on the possible pathways associated with the key differentially expressed proteins (DEPs) and its implication in various infertility scenarios. A brief overview of advanced techniques and bioinformatic tools used for reproductive proteomics is presented. Key findings of proteomic-based studies on male and female reproduction are also presented. Furthermore, the chapter sheds light on the cellular pathways and potential biomarkers associated with male and female infertility. Proteomics coupled with bioinformatic analysis provides an ideal platform for non-invasive management of infertility in couples.

Association between early embryo morphokinetics plus cumulus cell gene expression and assisted reproduction outcomes in polycystic ovary syndrome women

RESEARCH QUESTION

Can a combination of time-lapse morphokinetic parameters and cumulus cell gene expression in polycystic ovary syndrome (PCOS) women be used to predict assisted reproductive treatment outcome?

DESIGN

A total of 547 embryos from 100 intracytoplasmic sperm injection (ICSI) cycles were evaluated. Fifty women with PCOS and 50 women who were categorized as tubal factor infertility were recruited. Time-lapse records were annotated for time to pronuclear fading (tPNf), time to 2 to 8 cells (t2-t8), reverse cleavage, direct cleavage and also for the presence of multinucleation. Expression levels of three genes involved in mitotic divisions, diaphanous-related formin 2 (DIAPH2), nibrin (NBN) and NIMA-related protein kinase (NEK4), were measured in 100 associated cumulus cell samples using quantitative real-time polymerase chain reaction.

RESULTS

Expression of DIAPH2 and NBN was significantly higher in the embryos of PCOS patients that resulted in implantation, biochemical and clinical pregnancies as well as live birth compared with embryos that were negative for these outcomes (P <0.01). However, in the tubal factor group, NBN gene expression was significantly higher in embryos resulting in biochemical pregnancy, clinical pregnancy and live birth (P <0.01) only. Multivariate logistic regression analysis showed that tPNf together with DIAPH2 gene expression were independent prognostic factors of clinical pregnancy rate and live birth in both groups.

CONCLUSIONS

Some time-lapse embryo parameters may be related to cumulus gene expression and clinical outcome. Furthermore, the expressions of cumulus cell genes involved in mitotic divisions are significantly associated with ICSI outcome using Day 3 embryo transfer.

Analyzing the Transcriptome Profile of Human Cumulus Cells Related to Embryo Quality via RNA Sequencing

Selecting excellent oocytes is required to improve the outcomes of in vitro fertilization (IVF). Cumulus cells (CCs) are an integral part of the oocyte maturation process. Therefore, we sought to identify differentially expressed genes in CCs to assess oocyte quality and embryo development potential. We divided the participants' embryos into the high-quality embryo group and low-quality embryo group by the information including age, body mass index, and the levels of luteinizing hormone, follicle-stimulating hormone, estradiol, and progesterone. We analyzed a total of 7 CC samples after the quality control in RNA sequencing. We found that 2499 genes were unregulated and 5739 genes were downregulated in high-quality embryo group compared to the low-quality embryo group (Padj < 0.05). Interestingly, MSTN, CTGF, NDUFA1, VCAN, SCD5, and STAR were significantly associated with the quality of embryo. In accordance with the results of RNA sequencing, the association of the expression levels of MSTN, CTGF, NDUFA1, VCAN, SCD5, and STAR with the embryo quality was verified by quantitative reverse-transcription polymerase chain reaction (RT-qPCR) in 50 CC samples. Despite the small sample size and lack of validation in animal models, our study supports the fact that differential gene expression profile of human CCs, including MSTN, CTGF, NDUFA1, VCAN, SCD5, and STAR, can serve as potential indicator for embryo quality.

The Use of Proteomics in Assisted Reproduction

Despite the explosive increase in the use of Assisted Reproductive Technologies (ART) over the last 30 years, their success rates remain suboptimal. Proteomics is a rapidly-evolving technology-driven science that has already been widely applied in the exploration of human reproduction and fertility, providing useful insights into its physiology and leading to the identification of numerous proteins that may be potential biomarkers and/or treatment targets of a successful ART pregnancy. Here we present a brief overview of the techniques used in proteomic analyses and attempt a comprehensive presentation of recent data from mass spectrometry-based proteomic studies in humans, regarding all components of ARTs, including the male and female gamete, the derived zygote and embryo, the endometrium and, finally, the ART offspring both pre- and postnatally.

Biobanking of different body fluids within the frame of IVF-a standard operating procedure to improve reproductive biology research

Purpose

The aim of the present study was to develop a standard operating procedure (SOP) for the collection, transport, and storage of human cumulus cells, follicular fluid, blood serum, seminal plasma, embryo culture supernatant, and embryo culture supernatant control obtained within the IVF process under approved protocols and written informed consent from participating patients. The SOP was developed at the Kinderwunsch Institut Schenk, Dobl, Austria, together with Biobank Graz of the Medical University of Graz, Austria.

Methods

The SOP provides comprehensive details of laboratory procedures and sampling of the different fluids within the IVF process. Furthermore, information on sample coding, references of involved laboratory techniques (e.g., oocyte retrieval with a Steiner-TAN needle), ethical approvals, and biobanking procedures are presented.

Results

The result of the present study is a standard operating procedure.

Conclusions

The SOP ensures a professional way for collection and scientific use of IVF samples by the Kinderwunsch Institut Schenk, Dobl, Austria, and Biobank Graz of the Medical University of Graz, Austria. It can be used as a template for other institutions to unify specimen collection procedures in the field of reproductive health research.