Proteomic analysis of recurrent spontaneous abortion: Identification of an inadequately expressed set of proteins in human follicular fluid

Comparative proteomics analysis of decidua reveals altered RNA processing and impaired ribosome function in recurrent pregnancy loss

INTRODUCTION

Factors contributing to recurrent pregnancy loss (RPL) in more than half of the cases are still unknown. The incidence and societal impact of this condition requires urgent elucidation of the mechanisms behind it, which could aid in significant improvement of clinical management.

MATERIALS AND METHODS

Using a highly efficient in-solution digestion method and label-free data-independent LC-MS/MS acquisition with ion mobility, we performed comparative proteomics analysis of the decidua tissues from 19 RPL patients and 10 controls. Differentially abundant proteins (DAPs) were compared and correlated with 3 publicly available transcriptomic datasets and the expression of selected biomarkers was tested by qPCR in decidua and chorionic villi from an extended cohort.

RESULTS

From 1952 proteins identified based on ≥2 peptides, the statistically significant difference in abundance (Anova p ≤ 0.05) and fold change ≥1.2 showed 85 proteins. Pathway analysis using Reactome, KEGG and Wiki pathways identified enrichment of "Signaling by ROBO receptors", "RNA degradation" and "Cytoplasmic Ribosomal Proteins". The correlation between protein and gene expression in decidua revealed that the down-regulated ribosomal proteins in our dataset (RPS15, RPS17, RPL27A, RPL35A and RPL18) showed the same regulation trend at the mRNA level, which was later confirmed for transcripts of RPS15 and RPL18 in our cohort.

DISCUSSION

Our data suggests that the potential causes of RPL from the maternal side could be associated with impaired RNA processing machinery. Furthermore, the list of DAPs in RPL opens future investigations in terms of screening novel gene variants predisposing to pregnancy failure and developing biomarkers for RPL risk.

A Proteomic Analysis of Human Follicular Fluid: Proteomic Profile Associated with Embryo Quality

Embryo selection is a key point of in vitro fertilization (IVF). The most commonly used method for embryo selection is morphological assessment. However, it is sometimes inaccurate. Follicular fluid (FF) contains a complex mixture of proteins that are essential for follicle development and oocyte maturation. Analyzing human FF proteomic profiles and identifying predictive biomarkers might be helpful for evaluating embryo quality. A total of 22 human FF samples were collected from 19 infertile women who underwent IVF/intracytoplasmic sperm injection (ICSI) treatment between October 2021 and November 2021. FFs were grouped into two categories on the basis of the day 3 embryo quality, grade I or II in the hqFF group and grade III in the nhqFF group. FF was analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS). The key differentially expressed proteins (DEPs) were validated by parallel reaction monitoring (PRM) and enzyme-linked immunosorbent assay (ELISA). Differentially expressed proteins were further analyzed using DAVID software. A total of 558 proteins were identified, of which 50 proteins were differentially expressed in the hqFF versus nhqFF group, including 32 upregulated proteins (> 1.20-fold, P < 0.05) and 18 downregulated proteins (< 0.67-fold, P < 0.05). Bioinformatics analyses showed that the upregulated DEPs were enriched in components of the coagulation and complement systems and negative regulation of peptidase activity, while the downregulated DEPs were enriched in molecular function of extracellular matrix structural and constituent collagen binding. Our results suggested that a number of protein biomarkers in FF were associated with embryo quality. It may help develop an effective and noninvasive method for embryo selection.

PGK1 modulates balance between pro- and anti-inflammatory cytokines by interacting with ITI-H4

Inter-α-trypsin inhibitor heavy chain 4 (ITI-H4) is one of the acute phase proteins and is mainly related with inflammatory diseases such as bacterial bloodstream infection and recurrent pregnancy loss (RPL). In a previous study, ITI-H4 was reported to be cleaved by kallikrein B1 (KLKB1) and its cleaved form induces the imbalance between pro- and anti-inflammatory cytokines. Therefore, in this study, putative substrates of ITI-H4 were isolated by immunoprecipitation and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) analysis. Of those, phosphoglycerate kinase 1 (PGK1) was found to be a binding protein of ITI-H4. PGK1 increases the level of ITI-H4 expression and blocks the cleavage of ITI-H4 mediated by KLKB1. It also inhibits pro-inflammatory response by inhibiting the JAK2/STAT3 signaling pathway. Therefore, PGK1, a novel binding partner of ITI-H4, is expected to have cellular functions in the pathogenesis of ITI-H4-related inflammatory diseases.

Decreased histidine-rich glycoprotein and increased complement C4-B protein levels in follicular fluid predict the IVF outcomes of recurrent spontaneous abortion

BACKGROUND

Recurrent spontaneous abortion (RSA) is a common and complicated pregnancy-related disease that lacks a suitable biomarker to predict its recrudescence.

METHODS

Tandem mass tag (TMT) analysis was conducted to obtain quantitative proteomic profiles in follicular fluid from patients with a history of RSA and from control group. ELISA validation of candidate differentially expressed proteins was conducted in a larger group of patients.

RESULTS

A total of 836 proteins were identified by TMT analysis; 51 were upregulated and 47 were downregulated in follicular fluid from cases of RSA versus control group. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis revealed several important pathways were enriched, involving a dysregulated immunoglobulin Fc receptor signaling pathway and overactivated complement cascade pathways. ELISA validated the differential expression of two proteins, histidine-rich globulin (HRG) and complement C4-B (C4B), which were downregulated and upregulated, respectively, in follicular fluid of patients with RSA. We performed receiver operating characteristic curve analysis of the ELISA results with the outcomes of current IVF cycles as classification variables. The area under the curve results for HRG alone, C4B alone and HRG-C4B combined were 0.785, 0.710 and 0.895, respectively.

CONCLUSIONS

TMT analysis identified 98 differentially expressed proteins in follicular fluid from patients with RSA, indicating follicle factors that act as early warning factors for the occurrence of RSA. Among them, HRG and C4B provide candidate markers to predict the clinical outcomes of IVF/ICSI cycles, and the potential for modeling an early detection system for RSA.

Obesity-related alterations in protein expression in human follicular fluid from women undergoing in vitro fertilization

OBJECTIVE

To compare the proteomic composition of follicular fluid from women with normal weight vs. women with obesity but without a history of polycystic ovary syndrome or known ovarian dysfunction undergoing in vitro fertilization.

DESIGN

Cross-sectional.

SETTING

Academic medical center.

PATIENT(S)

Eight women with normal weight and 8 women with obesity undergoing in vitro fertilization and without a history of polycystic ovary syndrome, ovulatory dysfunction, diminished ovarian reserve, or known endometriosis were included in the analysis.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Proteomic assessment using liquid chromatography-mass spectrometry analysis.

RESULT(S)

The mean age of women with normal weight was similar to that of women with obesity (32.9 vs. 32.6 years, not significant). The mean body mass index of women with normal weight was 21.2 kg/m² compared with a body mass index of 37.1 kg/m² in women with obesity. A total of 1,174 proteins were identified with ≥2 peptides present. Twenty-five proteins were found to be significantly altered in the follicular fluid from women with obesity. Of these 25 proteins, 19 were up-regulated and 6 were down-regulated. Notably, C-reactive protein was 11-fold higher in the follicular fluid from women with obesity than in the follicular fluid from women with normal weight.

CONCLUSION(S)

Obesity is associated with dysregulation at the level of the follicle, including alterations in proteins related to inflammation and metabolism. These include proteins with emerging roles in energy homeostasis and follicular regulation.

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 &gt; 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 &lt; 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 &lt; 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) &gt; 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.

Nuclear Progestin Receptor-mediated Linkage of Blood Coagulation and Ovulation

Ovulation is a dramatic remodeling process that includes rupture of blood capillaries and clotting, but coagulation is not thought to directly regulate this process. Herein, we report remarkable increases of coagulation factors V (f5, ~3145-fold) and tissue factor (f3a, ~120-fold) in zebrafish ovarian follicle cells during ovulation. This increase was mediated through the nuclear progestin receptor (Pgr), which is essential for ovulation in zebrafish, and was totally abolished in ovarian follicular cells from pgr-/- mutants. In addition, promoter activities of f5 and f3a were significantly enhanced by progestin (DHP) via Pgr. Similar regulation of human F5 promoter activity was induced via human PGRB, suggesting a conserved mechanism. Site-directed mutagenesis of the zebrafish f5 promoter further demonstrated a direct regulation of coagulation factors via progestin response elements. Moreover, a stark increase of erythrocytes occurred in capillaries meshed in wild-type preovulatory follicles but was absent in pgr-/- mutants. Interestingly, anticoagulants significantly inhibited ovulation both in vitro and in vivo, respectively. Furthermore, reduced fecundity was observed in f5+/- female zebrafish. Taken together, our study provides plausible evidence for steroid regulation of coagulation factors, and a new hypothesis for blood clotting-triggered ovulation in vertebrates.

Proteomic Analysis of Human Follicular Fluid Reveals the Pharmacological Mechanisms of the Chinese Patent Drug Kunling Pill for Improving Diminished Ovarian Reserve

Objective. To explore the pharmacological mechanism of a Chinese patent drug (Kunling Pill (KLP)) on improving diminished ovarian reserve based on proteomic analysis. Methods. A total of 18 patients divided into three groups (the normal ovary reserve (NOR), diminished ovary reserve (DOR), and KLP groups) undergoing assisted reproductive technology by standard ovarian stimulation protocols were recruited to collect follicular fluid. Data-independent acquisition mass spectrometry was used to identify differentially expressed proteins by nano-LC-MS/MS. Bioinformatic analysis was conducted to predict the functions and pathways of the identified proteins. Clinical, hormonal, and biochemical parameters were also analyzed in the three groups. Results. A total of 144 differentially expressed proteins were screened out, including 56 proteins that were downregulated and 88 proteins that were upregulated in the DOR group compared with the NOR group, while 27 proteins were shared in the KLP-treated group. Among them, 10 proteins were upregulated and 17 proteins were downregulated in the KLP-treated group compared with the DOR group. The most enriched biological processes accounted for 28 GO terms, including cellular process, biological regulation, metabolic process, and regulation of biological process. Significant pathways were associated with fatty acid elongation, fatty acid degradation, fatty acid metabolism, nicotinate and nicotinamide metabolism, and valine, leucine, and isoleucine degradation. Conclusion. Our study provides the proteome profiles of human follicular fluid from DOR patients treated by KLP. Functional analyses of proteome datasets revealed that core proteins (SAA1, MIF, and PRDX5) and related pathways (fatty acid metabolism, nicotinate and nicotinamide metabolism, and tyrosine and purine metabolism) are possible pharmacological mechanisms through which KLP improves DOR. Therefore, these findings may help better understand the complex mechanisms through which DOR is treated by the Chinese patent drug KLP.

Non-invasive oocyte quality assessment

Oocyte quality is perhaps the most important limiting factor in female fertility; however, the current methods of determining oocyte competence are only marginally capable of predicting a successful pregnancy. We aim to review the predictive value of non-invasive techniques for the assessment of human oocytes and their related cells and biofluids that pertain to their developmental competence. Investigation of the proteome, transcriptome, and hormonal makeup of follicular fluid, as well as cumulus-oocyte complexes are currently underway; however, prospective randomized non-selection-controlled trials of the future are needed before determining their prognostic value. The biological significance of polar body morphology and genetics are still unknown and the subject of debate. The predictive utility of zygotic viscoelasticity for embryo development has been demonstrated, but similar studies performed on oocytes have yet to be conducted. Metabolic profiling of culture media using human oocytes are also limited and may require integration of automated, high-throughput targeted metabolomic assessments in real time with microfluidic platforms. Light exposure to oocytes can be detrimental to subsequent development and utilization of time-lapse imaging and morphometrics of oocytes is wanting. Polarized light, Raman microspectroscopy, and coherent anti-Stokes Raman scattering are a few novel imaging tools that may play a more important role in future oocyte assessment. Ultimately, the integration of chemistry, genomics, microfluidics, microscopy, physics, and other biomedical engineering technologies into the basic studies of oocyte biology, and in testing and perfecting practical solutions of oocyte evaluation, are the future for non-invasive assessment of oocytes.

Arachidonic Acid in Follicular Fluid of PCOS Induces Oxidative Stress in a Human Ovarian Granulosa Tumor Cell Line (KGN) and Upregulates GDF15 Expression as a Response

Polycystic ovarian ovary syndrome (PCOS) is the main cause of ovulatory infertility and a common reproductive endocrine disease of women in reproductive age. In addition, nearly half of PCOS patients are associated with obesity, and their total free fatty acids tend to increase. Arachidonic acid (AA) is a polyunsaturated fatty acid. Oxidation products of AA reacting with various enzymes[cyclooxygenases (COX), lipoxygenases (LOX), cytochrome P450s (CYP)] can change cellular mitochondrial distribution and calcium ion concentration, and increase reactive oxygen species (ROS) production. In this study, we analyzed the follicular fluid fatty acids and found higher levels of C20:4n6 (AA) in PCOS patients than in normal control subjects. Also, to determine whether AA induces oxidative stress (OS) in the human ovarian granulosa tumor cell line (KGN) and affects its function, we treated KGN cells with or without reduced glutathione (GSH) and then stimulated them with AA. The results showed that AA significantly reduced the total antioxidant capacity (TAC) and activity of antioxidant enzymes and increased the malondialdehyde (MDA), ROS and superoxide anion(O_2-)levels in KGN cells. In addition, AA was also found to impair the secretory and mitochondrial functions of KGN cells and induce their apoptosis. We further investigated the downstream genes affected by AA in KGN cells and its mechanism of action. We found that AA upregulated the expression of growth differentiation factor 15 (GDF15), which had a protective effect on inflammation and tissue damage. Therefore, we investigated whether AA-induced OS in KGN cells upregulates GDF15 expression as an OS response.Through silencing of GDF15 and supplementation with recombinant GDF15 (rGDF15), we found that GDF15, expressed as an OS response, protected KGN cells against AA-induced OS effects, such as impairment of secretory and mitochondrial functions and apoptosis. Therefore, this study suggested that AA might induce OS in KGN cells and upregulate the expression of GDF15 as a response to OS.

Proteomics and enriched biological processes in Antiphospholipid syndrome: A systematic review

Identification of differentially expressed proteins in antiphospholipid syndrome (APS) is a developing area of research for unique profiles of this pathology. Advances in technologies of mass spectrometry brings improvements in proteomics and results in assessment of soluble or cellular proteins which could be candidates for clinical biomarkers of primary APS. The use of blood as a source of proteins ease the acquisition of samples for proteomics analyses and later for disease diagnosis. We performed a systematic review to explore the proteomics studies carried out in circulating released proteins (serum, plasma) or cellular proteins (monocytes and platelets) of APS patients. The study groups differentiate among clinical APS cases with the aim to translate molecular findings to disease stratification and to improve APS diagnosis and prognosis. These studies also include the unravelling of new autoantibodies in non-criteria APS or how post-translational protein modifications provides clues about the pathological mechanisms of antigen-autoantibody recognition. Herein, we identified 82 proteins that were dysregulated in APS across eleven studies. Enrichment analysis revealed its connection to cellular activation and degranulation that eventually leads to thrombosis as the main biological process highlighted by these studies. Validation of APS-relevant proteins by functional and mechanistic studies will be essential for patient stratification and the development of targeted therapies for every clinical subtype of APS.

The proteomes of endometrial stromal cell-derived extracellular vesicles following a decidualizing stimulus define the cells' potential for decidualization success

Adequate endometrial stromal cell (ESC) decidualization is vital for endometrial health. Given the importance of extracellular vesicles (EVs) in intercellular communication, we investigated how their protein landscape is reprogrammed and dysregulated during decidual response. Small EVs (sEVs) from human ESC-conditioned media at Day-2 and -14 following decidual stimuli were grouped as well- (WD) or poorly decidualized (PD) based on their prolactin secretion and subjected to mass spectrometry-based quantitative proteomics. On Day 2, in PD- versus WD-ESC-sEVs, 17 sEV- proteins were down-regulated (C5, C6; complement/coagulation cascades, and SERPING1, HRG; platelet degranulation and fibrinolysis) and 39 up-regulated (FLNA, COL1A1; focal adhesion, ENO1, PKM; glycolysis/gluconeogenesis, and RAP1B, MSN; leukocyte transendothelial migration). On Day 14, in PD- versus WD-ESC-sEVs, FLNA was down-regulated while 21 proteins were up-regulated involved in complement/coagulation cascades (C3, C6), platelet degranulation (SERPINA4, ITIH4), B-cell receptor signalling and innate immune response (immunoglobulins). Changes from Days 2 to 14 suggested a subsequent response in PD-ESC-sEVs with 89 differentially expressed proteins mostly involved in complement and coagulation cascades (C3, C6, C5), but no change in WD-ESC-sEVs ESC. Poor decidualization was also associated with loss of crucial sEV-proteins for cell adhesion and invasion (ITGA5, PFN1), glycolysis (ALDOA, PGK1) and cytoskeletal reorganization (VCL, RAC1). Overall, this study indicates varied ESC response even prior to decidualization and provides insight into sEVs-proteomes as a benchmark of well-decidualized ESC. It shows distinct variation in sEV-protein composition depending on the ESC decidual response that is critical for embryo implantation, enabling and limiting trophoblast invasion during placentation and sensing a healthy embryo.

The effect of follicular fluid selenium concentration on oocyte maturation in women with polycystic ovary syndrome undergoing in vitro fertilization/Intracytoplasmic sperm injection: A cross-sectional study

BACKGROUND

A high level of free radicals and oxidative substances in women with polycystic ovary syndrome (PCOS) can affect the ovaries through oxidative stress. Antioxidants such as selenium, a vital trace element in human health, can improve the prognosis of PCOS by reducing oxidative stress.

OBJECTIVE

This study was performed due to the lack of comprehensive information about selenium concentration in follicular fluid and its effect on the oocyte count and quality in infertile women with PCOS.

MATERIALS AND METHODS

In this cross-sectional study, 78 women with PCOS referred to Umm-al-Banin Infertility Clinic Center, Ganjavian Hospital, Dezful, Iran for in-vitro fertilization from March to November 2019 were enrolled. After ovarian stimulation with the antagonist protocol, the oocytes were retrieved under transvaginal ultrasound in in-vitro fertilization/intracytoplasmic sperm injection cycles, and selenium concentrations were measured in the follicular fluid using an atomic absorption method by spectrophotometer device. Oocyte count and morphology were evaluated using inverted optical microscopy.

RESULTS

There were no significant differences between follicular fluid selenium concentrations in terms of the total number of oocytes and immature oocytes in the metaphase I and germinal vesicle stages. However, a significantly reduced number of metaphase II oocytes was observed at selenium levels < 40 μg/dL (p = 0.001).

CONCLUSION

Based on our results, low levels of follicular selenium concentration in infertile women with PCOS can reduce the quality and potency of oocyte maturation.

Metabolomics in Prenatal Medicine: A Review

Pregnancy is a complicated and insidious state with various aspects to consider, including the well-being of the mother and child. Developing better non-invasive tests that cover a broader range of disorders with lower false-positive rates is a fundamental necessity in the prenatal medicine field, and, in this sense, the application of metabolomics could be extremely useful. Metabolomics measures and analyses the products of cellular biochemistry. As a biomarker discovery tool, the integrated holistic approach of metabolomics can yield new diagnostic or therapeutic approaches. In this review, we identify and summarize prenatal metabolomics studies and identify themes and controversies. We conducted a comprehensive search of PubMed and Google Scholar for all publications through January 2020 using combinations of the following keywords: nuclear magnetic resonance, mass spectrometry, metabolic profiling, prenatal diagnosis, pregnancy, chromosomal or aneuploidy, pre-eclampsia, fetal growth restriction, pre-term labor, and congenital defect. Metabolite detection with high throughput systems aided by advanced bioinformatics and network analysis allowed for the identification of new potential prenatal biomarkers and therapeutic targets. We took into consideration the scientific papers issued between the years 2000-2020, thus observing that the larger number of them were mainly published in the last 10 years. Initial small metabolomics studies in perinatology suggest that previously unidentified biochemical pathways and predictive biomarkers may be clinically useful. Although the scientific community is considering metabolomics with increasing attention for the study of prenatal medicine as well, more in-depth studies would be useful in order to advance toward the clinic world as the obtained results appear to be still preliminary. Employing metabolomics approaches to understand fetal and perinatal pathophysiology requires further research with larger sample sizes and rigorous testing of pilot studies using various omics and traditional hypothesis-driven experimental approaches.

Follicular Fluid Zinc Level and Oocyte Maturity and Embryo Quality in Women with Polycystic Ovary Syndrome

Background:

Polycystic ovary syndrome (PCOS) is considered to be one of the most common endocrine disorders in women of reproductive age. Zinc, a vital trace element in the body, plays a key role in maintaining health, especially due to its antioxidant role. On the other hand, lack of antioxidants and oxidative stress can adversely affect oocytes quality and consequently fertility rate. The available studies that report the effect of follicular fluid (FF) zinc in terms of the number and quality of the oocytes in infertile women with PCOS, are few and not consistent. We decided to investigate this issue.

Materials and Methods:

In this cross-sectional study, from the women with PCOS referring to Omolbanin Hospital, Dezful, Iran (February to December 2019), a total of 90 samples (follicular fluid, oocytes, and embryos) were collected from those who had undergone in vitro fertilization (IVF). To measure zinc level in follicular fluid, high performance liquid chromatograpy (HPLC) was utilized. Also, oocytes maturity and embryos quality evaluation was performed using inverted optical microscopy. One-way ANOVA and Fisher’s least significant difference (LSD) were used for data analysis.

Results:

The amount of FF zinc was not associated with any significant differences in the number of oocytes and metaphase I (MI) and germinal vesicle (GV) oocytes, but a significant decrease was observed in the number of metaphase II (MII) oocytes at zinc values less than 35 µg/dL. The FF zinc levels less than 35 µg/dL were also significantly associated with decreased embryo quality

Conclusion:

A significant relationship was found between the level of FF zinc and the quality and the number of oocytes taken from the ovaries of infertile patients with PCOS history who were candidates for IVF treatment as well as the number of high quality embryos.

Expression of tissue factor and tissue factor pathway inhibitors during ovulation in rats: a relevance to the ovarian hyperstimulation syndrome

BACKGROUND

Blood coagulation has been associated with ovulation and female infertility. In this study, the expression of the tissue factor system was examined during ovulation in immature rats; the correlation between tissue factor and ovarian hyperstimulation syndrome (OHSS) was evaluated both in rats and human follicular fluids.

METHODS

Ovaries were obtained at various times after human chorionic gonadotropin (hCG) injection to investigate the expression of tissue factor system. Expression levels of ovarian tissue factor, tissue factor pathway inhibitor (Tfpi)-1 and Tfpi-2 genes and proteins were determined by real-time quantitative polymerase chain reaction (qPCR), and Western blot and immunofluorescence analyses, respectively. Expression levels of tissue factor system were also investigated in ovaries of OHSS-induced rats and in follicular fluid of infertile women.

RESULTS

The expression of tissue factor in the preovulatory follicles was stimulated by hCG, reaching a maximum at 6 h. Tissue factor was expressed in the oocytes and the preovulatory follicles. Tfpi-2 mRNA levels were mainly increased by hCG in the granulosa cells whereas the mRNA levels of Tfpi-1 were decreased by hCG. Human CG-stimulated tissue factor expression was inhibited by the progesterone receptor antagonist. The increase in Tfpi-2 expression by hCG was decreased by the proliferator-activated receptor γ (PPARγ) antagonist. Decreased expression of the tissue factor was detected in OHSS-induced rats. Interestingly, the tissue factor concentrations in the follicular fluids of women undergoing in vitro fertilization were correlated with pregnancy but not with OHSS.

CONCLUSIONS

Collectively, the results indicate that tissue factor and Tfpi-2 expression is stimulated during the ovulatory process in rats; moreover, a correlation exists between the levels of tissue factor and OHSS in rats but not in humans.

APC loss induces Warburg effect via increased PKM2 transcription in colorectal cancer

BACKGROUND

Most cancer cells employ the Warburg effect to support anabolic growth and tumorigenesis. Here, we discovered a key link between Warburg effect and aberrantly activated Wnt/β-catenin signalling, especially by pathologically significant APC loss, in CRC.

METHODS

Proteomic analyses were performed to evaluate the global effects of KYA1797K, Wnt/β-catenin signalling inhibitor, on cellular proteins in CRC. The effects of APC-loss or Wnt ligand on the identified enzymes, PKM2 and LDHA, as well as Warburg effects were investigated. A linkage between activation of Wnt/β-catenin signalling and cancer metabolism was analysed in tumour of Apcmin/+ mice and CRC patients. The roles of PKM2 in cancer metabolism, which depends on Wnt/β-catenin signalling, were assessed in xenograft-tumours.

RESULTS

By proteomic analysis, PKM2 and LDHA were identified as key molecules regulated by Wnt/β-catenin signalling. APC-loss caused the increased expression of metabolic genes including PKM2 and LDHA, and increased glucose consumption and lactate secretion. Pathological significance of this linkage was indicated by increased expression of glycolytic genes with Wnt target genes in tumour of Apcmin/+ mice and CRC patients. Warburg effect and growth of xenografted tumours-induced by APC-mutated-CRC cells were suppressed by PKM2-depletion.

CONCLUSIONS

The β-catenin-PKM2 regulatory axis induced by APC loss activates the Warburg effect in CRC.

The Role of Exosomes in Diseases Related to Infertility

Exosomes, small extracellular vesicles with diameters of 40-100nm, are generated through the fusion of multivessel with plasma membrane and secreted by a variety of living cells. Exosomes contain lipid bilayer membrane and releasable functionally active proteins, mRNA and microRNAs (miRNAs). This article reviews the latest progress of researches on exosomes in diseases that lead to infertility.

Expressed proteins and activated pathways in conditioned embryo culture media from IVF patients are diverse according to infertility factors

OBJECTIVE

Given that the embryo culture medium secretome reflects the embryo development, we hypothesize that protein profiles are affected according to infertility factors, which can be responsible for detrimental embryonic developmental competence. The aim of this study was to screen the protein profile of conditioned embryo culture media in patients presenting deep infiltrating endometriosis (ENDO) and polycystic ovarian syndrome (PCOS) undergoing IVF, by proteomics approaches. The control group was constituted by tubal factor patients.

METHODS

Patients underwent in vitro fertilization (IVF) treatment as routine and oocytes were fertilized by ICSI. The embryos were group cultured until day 3 of development, and after transfer the culture media were collected. For the proteomics analysis, two pools of samples were prepared for groups CONTROL and PCOS, and 4 pools of samples for group DIE. Samples were prepared to deplete high abundant proteins and followed evaluated by high throughput proteomics approach.

RESULTS

The embryonic organ and tissue development were physiological functions activated, based on proteins identified in the 3 study groups of samples. The samples coming from DIE patients presented a high calcium activity and on the other hand, embryos coming from PCOS patients showed a decreased calcium action. Other pathways as grow factors through the EGF signaling pathway overexpressed in ENDO culture medium and protein kinase A in PCOS were also observed.

CONCLUSIONS

Proteomic embryonic secretome will advance our knowledge of early embryogenesis and additionally could lead to improved selection of embryos for transfer warrants further investigation.

Pathogenetic factors involved in recurrent pregnancy loss from multiple aspects

Recurrent pregnancy loss (RPL) is a common complication in obstetrics, affecting about 5% of women of childbearing age. An increase in the number of abortions results in escalation in the risk of miscarriage. Although concentrated research has identified numerous causes for RPL, about 50% of them remain unexplained. Pregnancy is a complex process, comprising fertilization, implantation, organ and tissue differentiation, and fetal growth, which is effectively controlled by a number of both maternal and fetal factors. An example is the immune response, in which T cells and natural killer cells participate, and inflammation mediated by tumor necrosis factor or colony-stimulating factor, which hinders embryo implantation. Furthermore, vitamin D affects glucose metabolism and inhibits embryonic development, whereas microRNA has a negative effect on the gene expression of embryo implantation and development. This review examines the causes of RPL from multiple perspectives, and focuses on the numerous factors that may result in RPL.

Qualitative and Quantitative Analysis of Proteome and Peptidome of Human Follicular Fluid Using Multiple Samples from Single Donor with LC-MS and SWATH Methodology

Human follicular fluid (hFF) is a natural environment of oocyte maturation, and some components of hFF could be used to judge oocyte capability for fertilization and further development. In our pilot small-scale study three samples from four donors (12 samples in total) were analyzed to determine which hFF proteins/peptides could be used to differentiate individual oocytes and which are patient-specific. Ultrafiltration was used to fractionate hFF to high-molecular-weight (HMW) proteome (>10 kDa) and low-molecular-weight (LMW) peptidome (<10 kDa) fractions. HMW and LMW compositions were analyzed using LC-MS in SWATH data acquisition and processing methodology. In total we were able to identify 158 proteins, from which 59 were never reported before as hFF components. 55 (45 not reported before) proteins were found by analyzing LMW fraction, 67 (14 not reported before) were found by analyzing HMW fraction, and 36 were identified in both fractions of hFF. We were able to perform quantitative analysis for 72 proteins from HMW fraction of hFF. We found that concentrations of 11 proteins varied substantially among hFF samples from single donors, and those proteins are promising targets to identify biomarkers useful in oocyte quality assessment.

N-glycoproteomic analysis of human follicular fluid during natural and stimulated cycles in patients undergoing in vitro fertilization

OBJECTIVE

Hyperstimulation methods are broadly used for in vitro fertilization (IVF) in patients with infertility; however, the side effects associated with these therapies, such as ovarian hyperstimulation syndrome (OHSS), have not been well studied. N-glycoproteomes are subproteomes used for the remote sensing of ovarian stimulation in follicular growth. Glycoproteomic variation in human follicular fluid (hFF) has not been evaluated. In this study, we aimed to identify and quantify the glycoproteomes and N-glycoproteins (N-GPs) in natural and stimulated hFF using label-free nano-liquid chromatography/electrospray ionization-quad time-of-flight mass spectrometry.

METHODS

For profiling of the total proteome and glycoproteome, pooled protein samples from natural and stimulated hFF samples were selectively isolated using hydrazide chemistry to obtain the total proteomes and glycoproteomes. N-GPs were validated by the consensus sequence N-X-S/T (92.2% specificity for the N-glycomotif at p<0.05). All data were compared between natural versus hyperstimulated hFF samples.

RESULTS

We detected 41 and 44 N-GPs in the natural and stimulated hFF samples, respectively. Importantly, we identified 11 N-GPs with greater than two-fold upregulation in stimulated hFF samples compared to natural hFF samples. We also validated the novel N-GPs thyroxine-binding globulin, vitamin D-binding protein, and complement proteins C3 and C9.

CONCLUSION

We identified and classified N-GPs in hFF to improve our understanding of follicular physiology in patients requiring assisted reproduction. Our results provided important insights into the prevention of hyperstimulation side effects, such as OHSS.

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

PURPOSE

The goal for the present study was to implement a technique for protein extraction and identification in human cumulus cells (CCs).

METHODS

Forty samples of CCs were collected after ovum pick-up from patients undergoing intracytoplasmic sperm injection (ICSI). Samples were split into the blastocyst group (n = 10), including patients in which all embryos converted into blastocysts, and the non-blastocyst group (n = 10), including patients in which none of the embryos reached the blastocyst stage or the positive-pregnancy (n = 10) and negative-pregnancy group (n = 10). Proteins were extracted and injected into a liquid chromatography system coupled to a mass spectrometer. The spectra were processed and used to search a database.

RESULTS

There were 87 different proteins in samples from the blastocyst and non-blastocyst groups, in which 30 were exclusively expressed in the blastocyst group and 17 in the non-blastocyst group. Among the 72 proteins detected in the pregnancy groups, 19 were exclusively expressed in the positive, and 16 were exclusively expressed in the negative-pregnancy group.

CONCLUSIONS

CC proteomics may be useful for predicting pregnancy success and the identification of patients that should be included in extended embryo culture programs.

Protein pathways working in human follicular fluid: the future for tailored IVF?

The human follicular fluid (HFF) contains molecules and proteins that may affect follicle growth, oocyte maturation and competence acquiring. Despite the numerous studies, an integrated broad overview on biomolecular and patho/physiological processes that are proved or supposed to take place in HFF during folliculogenesis and oocyte development is still missing. In this review we report, for the first time, all the proteins unambiguously detected in HFF and, applying DAVID (Database for Annotation, Visualization and Integrated Discovery) and MetaCore bioinformatic resources, we shed new lights on their functional correlation, delineating protein patterns and pathways with reasonable potentialities for oocyte quality estimation in in vitro fertilisation (IVF) programs. Performing a rigorous PubMed search, we redacted a list of 617 unique proteins unambiguously-annotated as HFF components. Their functional processing suggested the occurrence in HFF of a tight and highly dynamic functional-network, which is balanced by specific effectors, primarily involved in extracellular matrix degradation and remodelling, inflammation and coagulation. Metalloproteinases, thrombin and vitamin-D-receptor/retinoid-X-receptor-alpha resulted as the main key factors in the nets and their differential activity may be indicative of ovarian health and oocyte quality. Despite future accurate clinical investigations are absolutely needed, the present analysis may provide a starting point for more accurate oocyte quality estimation and for defining personalised therapies in reproductive medicine.

Proteome Profile and Quantitative Proteomic Analysis of Buffalo (Bubalusbubalis) Follicular Fluid during Follicle Development

Follicular fluid (FF) accumulates in the antrum of the ovarian follicle and provides the microenvironment for oocyte development. FF plays an important role in follicle growth and oocyte maturation. The FF provides a unique window to investigate the processes occurring during buffalo follicular development. The observed low quality of buffalo oocytes may arise from the poor follicular microenvironment. Investigating proteins found in buffalo FF (BFF) should provide insight into follicular development processes and provide further understanding of intra-follicular maturation and oocytes quality. Here, a proteomic-based approach was used to analyze the proteome of BFF. SDS-PAGE separation combined with mass spectrometry was used to generate the proteomic dataset. In total, 363 proteins were identified and classified by Gene Ontology terms. The proteins were assigned to 153 pathways, including signaling pathways. To evaluate difference in proteins expressed between BFF with different follicle size (small, <4 mm; and large, >8 mm), a quantitative proteomic analysis based on multi-dimensional liquid chromatography pre-fractionation tandem Orbitrap mass spectrometry identification was performed. Eleven differentially expressed proteins (six downregulated and five upregulated in large BFF) were identified and assigned to a variety of functional processes, including serine protease inhibition, oxidation protection and the complement cascade system. Three differentially expressed proteins, Vimentin, Peroxiredoxin-1 and SERPIND1, were verified by Western blotting, consistent with the quantitative proteomics results. Our datasets offers new information about proteins present in BFF and should facilitate the development of new biomarkers. These differentially expressed proteins illuminate the size-dependent protein changes in follicle microenvironment.

Preconception folic acid use influences the follicle fluid proteome

BACKGROUND

The investigation of the human follicle fluid proteome has gained much interest in the search of new markers as predictors for in vitro fertilization and intracytoplasmic sperm injection (IVF/ICSI) treatment outcome. Follicular fluid folate, as substrate of one carbon (1-C) metabolism, affects follicular metabolism and oocyte and embryo quality. From this background, we aim to identify a folate-related follicle fluid proteome that associates with IVF/ICSI treatment outcome.

METHODS

In a nested case-control study embedded in a periconception cohort, we performed qualitative and quantitative proteomic analyses using nanoflow LC-MS/MS and TMT labelling in 30 monofollicular fluid samples from women undergoing IVF/ICSI treatment of which 15 used and 15 did not use a folic acid supplement. The protein data are analysed using scaffold proteome Software and differential abundances are expressed as Log2-fold change. Blood samples were obtained before and after treatment for determination of biomarkers of 1-C metabolism and estradiol.

RESULTS

We identified 227 uniquely expressed proteins in follicular fluid. In folic acid supplement users compared to nonusers, we established a lower abundance of C-reactive protein (-2.03; P = < 0.01) and higher abundances of apolipoproteins from high-density lipoprotein (HDL), most notably A-I (+1.28; P = < 0.01) and C-I (+1.11; P = 0.016).

CONCLUSION

Preconception folic acid supplement use is associated with suppression of the inflammatory pathway and upregulation of the HDL pathway in human follicular fluid, being a preferential source of cholesterol for steroid hormone synthesis. Studies are needed on the tissue specificity and on the beneficial effects of embryo quality and IVF/ICSI treatment outcome of the proteome of these pathways.

MiRNA-320 in the human follicular fluid is associated with embryo quality in vivo and affects mouse embryonic development in vitro

Previous work from our laboratory demonstrated the existence of miRNAs in human follicular fluid. In the current study, we have sought to identify miRNAs that might affect oocyte/embryo quality in patients undergoing intracytoplasmic sperm injection and to investigate their roles in in vitro fertilization outcomes in mouse oocytes. 53 samples were classified as Group 1 (high quality) if the day-3 embryos had seven and more cells or as Group 2 (low quality) if the embryos had six and fewer cells. TaqMan Human microRNAs cards and qRT-PCR were performed to verify differently expressed miRNAs. The function of the corresponding miRNA was investigated in mouse oocytes by injecting them with miRNA-inhibitor oligonucleotides. We found that hsa-miR-320a and hsa-miR-197 had significantly higher expression levels in the Group 1 follicular fluids than in Group 2 (p = 0.0073 and p = 0.008, respectively). Knockdown of mmu-miR-320 in mouse oocytes strongly decreased the proportions of MII oocytes that developed into two-cell and blastocyst stage embryos (p = 0.0048 and p = 0.0069, respectively). Wnt signaling pathway components had abnormal expression level in miR-320 inhibitor-injected oocytes. This study provides the first evidence that miRNAs in human follicular fluid are indicative of and can influence embryo quality.

Proteomic analysis of human follicular fluid from fertile women

Background

Follicular fluid is a unique biological fluid in which the critical events of oocyte and follicular maturation and somatic cell-germ cell communication occur. Because of the intimate proximity of follicular fluid to the maturing oocyte, this fluid provides a unique window into the processes occurring during follicular maturation. A thorough identification of the specific components within follicular fluid may provide a better understanding of intrafollicular signaling, as well as reveal potential biomarkers of oocyte health for women undergoing assisted reproductive treatment. In this study, we used high and low pH HPLC peptide separations followed by mass spectrometry to perform a comprehensive proteomic analysis of human follicular fluid from healthy ovum donors. Next, using samples from a second set of patients, an isobaric mass tagging strategy for quantitative analysis was used to identify proteins with altered abundances after hCG treatment.

Results

A total of 742 follicular fluid proteins were identified in healthy ovum donors, including 413 that have not been previously reported. The proteins belong to diverse functional groups including insulin growth factor and insulin growth factor binding protein families, growth factor and related proteins, receptor signaling, defense/immunity, anti-apoptotic proteins, matrix metalloprotease related proteins, and complement activity. In a quantitative analysis, follicular fluid samples from age-matched women undergoing in vitro fertilization oocyte retrieval were compared and 17 follicular fluid proteins were found at significantly altered levels (p < 0.05) between pre-hCG and post-hCG samples. These proteins belong to a variety of functional processes, including protease inhibition, inflammation, and cell adhesion.

Conclusions

This database of FF proteins significantly extends the known protein components present during the peri-ovulatory period and provides a useful basis for future studies comparing follicular fluid proteomes in various fertility, disease, and environmental exposure conditions. We identified 17 differentially expressed proteins after hCG treatment and together these data showed the feasibility for defining biomarkers that illuminate how the ovarian follicle microenvironment is altered in various infertility-related conditions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12014-015-9077-6) contains supplementary material, which is available to authorized users.

Regulation of pyruvate kinase isozyme M2 is mediated by the ubiquitin-specific protease 20

USP20, one of deubiquitinating enzymes (DUBs) belonging to the subfamily of ubiquitin-specific protease (USP), regulates ubiquitin-mediated protein degradation. So far, USP20 has been identified as a binding protein and a regulator of hypoxia-inducible factor (HIF)-1α, β-adrenergic receptor, and tumor necrosis factor (TNF) receptor associated factor 6 (TRAF6). In order to investigate other biological functions of USP20 with its novel substrates, we searched for putative substrates through two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF/MS) analysis. We found several putative substrates, some of which are related to cancer metabolism or neural disorders. Among these, the pyruvate kinase isoenzyme M2 (PKM2) had a high identity score. Most cancer cells contain a specific metabolic pathway, referred to as the Warburg effect. One well-known function of PKM2 is a main regulator in cancer metabolic pathways, and PKM2 promotes the Warburg effect and tumor growth. In addition, both PKM2 and HIF-1α upregulate the expression of target genes. From this evidence, it is expected that USP20 would be associated with the metabolic pathway through the regulation of PKM2 ubiquitination. Despite various roles of DUBs, the biological functions of USP20 in cellular mechanisms are poorly understood. Herein, we investigated the inter-action between PKM2 and USP20. Our results suggest a new molecular pathway in cancer metabolism through the regulation of PKM2.

Proteomics of follicular fluid from women with polycystic ovary syndrome suggests molecular defects in follicular development

CONTEXT

Polycystic ovary syndrome (PCOS), a major cause of anovulatory infertility, is characterized by arrested follicular growth. Altered protein levels in the follicular fluid surrounding the ovum may reflect the molecular defects of folliculogenesis in these women.

OBJECTIVE

To identify differentially regulated proteins in PCOS by comparing the follicular fluid protein repertoire of PCOS with healthy women.

METHODS

The follicular fluid samples were collected from PCOS and normo-ovulatory women undergoing in vitro fertilization. Follicular fluid proteins were subjected to digestion using trypsin, and resultant peptides were labeled with isobaric tags for relative and absolute quantification reagents and analyzed by liquid chromatography tandem mass spectrometry. Differential abundance of selected proteins was confirmed by ELISA.

RESULTS

A total of 770 proteins were identified, of which 186 showed differential abundance between controls and women with PCOS. Proteins involved in various processes of follicular development including amphiregulin; heparan sulfate proteoglycan 2; tumor necrosis factor, α-induced protein 6; plasminogen; and lymphatic vessel endothelial hyaluronan receptor 1 were found to be deregulated in PCOS. We also identified a number of new proteins from follicular fluid, whose function in the ovary is not yet clearly established. These include suprabasin; S100 calcium binding protein A7; and helicase with zinc finger 2, transcriptional coactivator.

CONCLUSIONS

Proteins indispensable for follicular growth were found to be differentially expressed in follicular fluid of women with PCOS, which may in part explain the aberrant folliculogenesis observed in these women.

Preliminary proteomic analysis on the alterations in follicular fluid proteins from women undergoing natural cycles or controlled ovarian hyperstimulation

PURPOSE

To study the differences in protein expression profiles of follicular fluid (FF) between controlled ovarian hyperstimulation (COH) and natural ovulatory cycles.

METHODS

Twelve infertile women undergoing in vitro fertilization and embryo transfer (IVF-ET), with matched clinical information, were retrospectively recruited in the IVF center of our university hospital, including six undergoing COH and another six with natural cycles. FF was sampled from dominant follicles with mature oocytes. Protein expression profiles in each FF sample were analyzed respectively using two-dimensional gel electrophoresis. Differentially expressed proteins were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and validated by western blotting. Differentially expressed proteins were further analyzed using Ingenuity Pathway Analysis (IPA) software.

RESULTS

Two proteins were downregulated and 11 proteins were upregulated (change ≥1.5-fold, P < 0.05) in the COH group. We identified one down-egulated and seven upregulated proteins using MALDI-TOF MS. Four differentially expressed proteins, including transferrin, complement component C3 (C3), haptoglobin and alpha-1-antitrypsin (AAT), were further validated by rate nephelometry and western blotting analyses. The IPA analysis revealed a significant network involved in the humoral immune and inflammatory responses.

CONCLUSIONS

The eight differentially expressed proteins were related to immune and inflammatory responses in the ovary. Our results provide new insights into the influence of COH on follicular (spp) development and IVF outcomes.

A proteomic analysis of human follicular fluid: comparison between younger and older women with normal FSH levels

The follicular fluid (FF) is produced during folliculogenesis and contains a variety of proteins that play important roles in follicle development and oocyte maturation. Age-related infertility is usually considered as a problem that can be solved by assisted reproduction technology. Therefore, the identification of novel biomarkers that are linked to reproductive aging is the subject of this study. FF was obtained from healthy younger (20–32 years old) and older (38–42 years old) women undergoing intracytoplasmic sperm injection (ICSI) due to male factor infertility. The FF was analyzed by two-dimensional gel electrophoresis (2-DE). The power of two-dimensional gel electrophoresis and the identification of proteins were exploited using matrix-assisted laser desorption-ionization time-of-flight/time-of-flight (MALDI-TOF-TOF) mass spectrometry. Twenty three protein spots showed reproducible and significant changes in the aged compared to the young group. Of these, 19 protein spots could be identified using MALDI-TOF-TOF-MS. As a result of MASCOT search, five unique downregulated proteins were identified in the older group. These were identified as serotransferrin, hemopexin precursor, complement C3, C4 and kininogen. A number of protein markers were found that may help develop diagnostic methods of infertility.

Proteome differences in the first- and third-trimester human placentas

Placenta is a transient and unique pregnancy tissue that supports the fetus nutritionally and metabolically. Expression of the unique placental proteins in different stages may influence the development of the fetus as well as the pregnancy outcome. The present study aimed to compare the total placental proteome differences between the normal first- and third-trimester human placentas. In the current study, placental proteome was compared between normal first- and third-trimester placentas using 2-dimensional polyacrylamide gel electrophoresis method for separation and matrix-assisted laser desorption/ionization time-of flight mass spectrometry technique for identification of the proteins. Despite the overall similarities, comparison of the mean intensity of the protein spots between the first- and third-trimester placental proteomes revealed that 22 spots were differentially expressed (P < .05) among which 11 distinct spots were successfully identified. Of the 11 differentially expressed proteins, 4 were increased (protein disulfide isomerase, tropomyosin 4 isoform 2, enolase 1, and 78-kDa glucose-regulated protein), while the remaining 7 (actin γ1 propeptide, heat shock protein gp96, α1-antitrypsin, EF-hand domain family member D1, tubulin α1, glutathione S-transferase, and vitamin D binding protein) showed decreased expression in the placentas from the first-trimester compared to the full-term ones. In summary, the results of the present study as the first research on the comparison of the first- and third-trimester human placental proteomes introduced a group of 11 proteins with altered expression. Interestingly, some of these proteins are reported to be altered in pregnancy-related disorders.

Alteration in the expression of proteins in unexplained recurrent pregnancy loss compared with in the normal placenta

The placenta is a unique pregnancy-related tissue and plays a key role in occurrence of unexplained recurrent pregnancy loss (URPL). Abnormal placentation might play a key role in occurrence of URPL. Therefore, the purpose of this study was to compare the human placental proteome between URPL placentas and normal placental matched for gestational week. Total placental proteins were extracted, and the two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) technique was used for separation of the placental proteomes. Protein spots differentially expressed between URPL and normal placentas were selected and identified by the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF/TOF) technique after being digested in the gel. Moreover, quantitative real-time PCR and Western blot techniques were used to confirm the differential expression mass results for some differentially expressed proteins. The results indicated that at least 19 protein spots were differentially expressed between URPL and normal placentas (P < 0.05), and twelve of them were successfully identified. While only two proteins were downregulated (calumenin and enolase 1), the remaining ten spots (actin gamma 1 propeptide, cathepsin D prepropeptide, heat shock protein gp96, tubulin beta, tubulin alpha 1, glutathione S-transferase, vitamin D binding protein, prohibitin, actin beta, apolipoprotein A-I) showed increased expression in URPL cases in comparison with normal placentas. Real-time PCR also confirmed the downregulation of calumenin and upregulation of prohibitin and apolipoprotein A-I at the mRNA levels. In conclusion, the results of the present study showed that alteration in the expression of proteins involved in proliferation and migration of endothelial cells as well as control of coagulation by these cells might play an important role in the pathogenesis of URPL.

Clinical proteomics in obstetrics and neonatology

Clinical proteomics has been applied to the identification of biomarkers of obstetric and neonatal disease. We will discuss a number of encouraging studies that have led to potentially valid biomarkers in the context of Down's syndrome, preterm birth, amniotic infections, preeclampsia, intrauterine growth restriction and obstructive uropathies. Obtaining noninvasive biomarkers (e.g., from the maternal circulation, urine or cervicovaginal fluid) may be more feasible for obstetric diseases than for diseases of the fetus, for which invasive methods are required (e.g., amniotic fluid, fetal urine). However, studies providing validated proteomics-identified biomarkers are limited. Efforts should be made to save well-characterized samples of these invasive body fluids so that many valid biomarkers of pregnancy-related diseases will be identified in the coming years using proteomics based analysis upon adoption of 'clinical proteomics guidelines'.

An integrated approach based on multiplexed protein array and iTRAQ labeling for in-depth identification of pathways associated to IVF outcome

The emergence of high-throughput protein quantification methodologies has enabled the comprehensive characterization by longitudinal and cross-sectional studies of biological fluids under physiological and pathological conditions. In particular, the simultaneous investigation of cytokines and growth factors signaling pathways and their associated downstream effectors by integrated multiplexed approaches offers a powerful strategy to gain insights into biological networks and processes in living systems. A growing body of research indicates that bioactive molecules of human reproductive fluids, including human follicular fluid (hFF), may affect oocyte quality, fertilization and embryo development, thus potentially influencing the physiopathology of pregnancy-related conditions.

In this work, an iTRAQ labeling strategy has been complemented with a multiplexed protein array approach to analyze hFFs with the aim to investigate biological processes and pathways related to in vitro fertilization (IVF) outcome. The iTRAQ labeling strategy lead to the quantification of 89 proteins, 30 of which were differentially expressed in hFFs with successful compared to unsuccessful IVF outcome. The targeted study, based on multiplexed antibody protein arrays, allowed the simultaneous quantification of 27 low abundance proteins, including growth factors, chemokines and cytokines endowed with pro- and anti-inflammatory activity. A significant number of differentially regulated proteins were involved in biological functions related to blood coagulation, acute phase response signaling and complement system. Overall, the present results provide an integrated overview of protein changes in hFFs associated to IVF outcome, thus improving current knowledge in reproductive medicine and fertility research.

Identification of microRNAs in human follicular fluid: characterization of microRNAs that govern steroidogenesis in vitro and are associated with polycystic ovary syndrome in vivo

CONTEXT

Human follicular fluid is a combination of proteins, metabolites, and ionic compounds that is indicative of the general state of follicular metabolism and is associated with maturation and quality of oocytes. Deviations in these components are often associated with reproductive diseases. There has been no report of microRNAs (miRNAs) in human follicular fluids.

OBJECTIVE

We hypothesized that human follicular fluid may contain miRNAs. We sought to identify cell-free miRNAs in human follicular fluid and to investigate the function of these miRNAs in vitro and any roles they play in polycystic ovary syndrome (PCOS).

DESIGN

Genome-wide deep sequencing and TaqMan miRNA arrays were used to identify miRNAs, and the roles of the highly expressed miRNAs in steroidogenesis were investigated in KGN cells. Quantification of candidate miRNAs in follicular fluids of PCOS and controls was performed using TaqMan miRNA assays.

RESULTS

We identified miRNAs in microvesicles and the supernatant of human follicular fluid. Bioinformatics analysis showed that the most highly expressed miRNAs targeted genes associated with reproductive, endocrine, and metabolic processes. We found that miR-132, miR-320, miR-520c-3p, miR-24, and miR-222 regulate estradiol concentrations and that miR-24, miR-193b, and miR-483-5p regulate progesterone concentrations. Finally, we showed that miR-132 and miR-320 are expressed at significantly lower levels in the follicular fluid of polycystic ovary patients than in healthy controls (P = .005 and P = .0098, respectively).

CONCLUSION

These results demonstrate that there are numerous miRNAs in human follicular fluids, some of which play important roles in steroidogenesis and PCOS. This study substantially revises our understanding of the content of human follicular fluid and lays the foundation for the future investigation of the role of miRNAs in PCOS.

Proteomic analysis of human follicular fluid: a new perspective towards understanding folliculogenesis

Human follicular fluid is a complex body fluid that constitutes the microenvironment of developing follicles in the ovary. Follicular fluid contains a number of proteins that modulate oocyte maturation and ovulation. Information about the protein constituents of follicular fluid may provide a better understanding of ovarian physiology in addition to opening new avenues for investigating ovarian disorders. However, the composition of follicular fluid proteome remains poorly defined. In this study, we carried out SDS-PAGE, OFFGEL and SCX-based separation followed by LC-MS/MS analysis to characterize the proteome of human follicular fluid. We report high confidence identification of 480 proteins, of which 320 have not been described previously in the follicular fluid. The identified proteins belong to diverse functional categories including growth factor and hormones, receptor signaling, enzyme catalysis, defense/immunity and complement activity. Our dataset should serve as a resource for future studies aimed at developing biomarkers for monitoring oocyte and embryo quality, pregnancy outcomes and ovarian disorders.

BIOLOGICAL SIGNIFICANCE

Proteome analysis of human follicular fluid by multi-pronged approach of protein peptide fractionation revealed 480 proteins with high confidence. The identified protein may facilitate the understanding of folliculogenesis. This protein dataset should serve as a useful resource for development of biomarkers for oocyte quality, in vitro fertilization techniques and female infertility.

Effect of porcine follicular fluid proteins and peptides on oocyte maturation and their subsequent effect on in vitro fertilization

The follicular fluid (FF) is a microenvironment that contains molecules involved in oocyte maturation, ovulation, and fertilization. Characterizing the proteins and peptides present in the FF could be useful for determining which proteins and peptides to use as a supplement for culture media. Biologically active peptides produced during the maturation or degradation of functional proteins are called cryptides. The aim of this study was to identify the proteins and cryptides in porcine FF that could stimulate porcine oocyte in vitro maturation (IVM) and in vitro fertilization (IVF) when added to culture maturation medium. Five FF protein fractions (F1-F5) were obtained by ionic exchange chromatography, resolved by SDS-PAGE, and identified by tandem mass spectrometry. These fractions had effects on IVM and/or IVF. The F1 fraction, which was composed of immunoglobulin fragments, cytokeratin, transferrin, and plasminogen precursor increased IVM and IVF. The F2, F3, and F4 fractions reduced the percentage of oocytes in first metaphase. Additionally, the F3 fraction, which was composed of immunoglobulins and transthyretin, interfered with germinal vesicle breakdown. The F5 fraction, which was mainly composed of serum albumin and keratin, favored germinal vesicle breakdown and promoted IVM. Most of the 31 proteins which were associated with the immune response and inflammatory processes could be related to oocyte maturation and fertilization. Some of the identified proteins were present in more than one fraction; this could be explained by a change in their isoelectric points, because of the loss of part of the amino acid sequence or a change in the glycosylation status of the protein. Improved oocyte IVM and IVF will increase embryo production, which in turn will contribute to the efficiency of assisted reproduction in various mammalian species.

Different protein expression patterns associated with polycystic ovary syndrome in human follicular fluid during controlled ovarian hyperstimulation

Polycystic ovary syndrome (PCOS) is one of the most common causes of anovulatory infertility, affecting 5-10% of females during their reproductive life. Currently the pathology of PCOS is largely unknown. To identify the differential protein expression in follicular fluids from PCOS and normal subjects during controlled ovarian hyperstimulation, we performed an initial proteomic study including two-dimensional gel electrophoresis (2DE) analysis and mass spectroscopy, and confirmed results by western blot. Thirty-two protein spots were shown to be significantly differentially expressed between PCOS and normal follicular fluids, of which 20 unique proteins were identified to be associated with cellular metabolism and physiological processes; 13 of these proteins were upregulated while seven were downregulated in PCOS follicular fluids. Western blotting analyses confirmed the differential expressions for three randomly selected proteins, i.e. upregulated α1-antitrypsin, apolipoprotein A-I and transferrin in follicular fluid from PCOS patients than normal controls. Furthermore, semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) analyses revealed that mRNA levels of serine palmitoyltransferase 2, serine/threonine-protein kinase male germ cell-associated kinase (MAK) and DNA damage-regulated autophagy modulator protein 2 decreased significantly in granulosa cells of PCOS patients compared with normal samples. These results increase our understanding of PCOS and the identified genes may serve as candidate biomarkers to develop diagnostic and therapeutic tools.