Single-cell Transcriptomes and Follicular Fluid Proteomics of Ovine Atretic Follicles Reveal the Underlying Mechanisms of Oocyte Degeneration
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ABSTRACT:
ORGANISM(S): Oestrus Ovis
SUBMITTER: 
Jiaxin Zhang
PROVIDER: PXD052738 | iProX | Thu May 30 00:00:00 BST 2024
REPOSITORIES: iProX
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Project description:Background: In mammals, female fertility is determined by the outcome of follicular development (ovulation or atresia). Follicular atresia is a complex physiological process that results in the degeneration of oocytes from the ovary. However, the molecular mechanisms of oocyte degeneration and key protein markers of follicular atresia remain unclear. In this study, we explored the complex transcriptional regulatory mechanisms and protein profiles in oocytes and follicular fluid in atretic follicle stages using single-cell RNA sequencing and tandem mass tag proteomics. Results: First, through paired analysis of different follicle development stages, we identified 175 atresia-specific genes and eight candidate oocyte-secreted factors, including PKG1, YTHDF2, and MYC. Meanwhile, we also characterized unique features of the oocyte transcriptional landscape in the atretic follicle stage that displayed cell death-related transcriptional changes and mechanisms, such as autophagy (TBK1 and IRS4), necroptosis (PKR), and apoptosis (MARCKS). Moreover, we identified atresia-specific genes, namely FTH1, TF, and ACSL4, which may participate in regulation of oocyte ferroptosis in atretic follicles through a series of mechanisms including ferritinophagy, ferritin transport, and lipid metabolism. Additionally, we uncovered 333 differentially expressed proteins that may coordinate follicular atresia and revealed key pathways, such as negative regulation of angiogenesis, metabolic pathways, and transcription and mRNA splicing, that lead to oocyte degeneration. Finally, by combining transcriptome and proteomics analyses, we identified two oocyte-secreted biomarkers, PGK1 and ANGPT2, that may be associated with follicular atresia. Conclusions: In conclusion, our work provides a comprehensive characterization of oocyte degeneration in ovine atretic follicles, which provides a basis for establishing an oocyte quality evaluation system and understanding the mechanism of follicular atresia in sheep, as well as an important reference for in vitro production of embryos.
2024-06-05 | GSE268651 | GEO
Project description:Reproductive aging is a major cause of fertility decline, attributed to decreased oocyte quantity and competence. Follicular somatic cells play crucial roles in the growth and development of the oocyte by providing nutrients and regulatory factors. Here we investigated how oocyte quality is affected by its somatic cell environment by creating chimeric follicles, whereby an oocyte from one follicle was transplanted into and cultured within another follicle whose native oocyte was removed. Somatic cells within the chimeric follicle re-establish connections with the oocyte and support oocyte growth and maturation in a three-dimensional (3D) culture system. We show that young oocytes transplanted into aged follicles exhibited reduced meiotic maturation and developmental potential, whereas the young follicular environment significantly improved the rates of maturation, blastocyst formation and live birth of aged oocytes. Aged oocytes cultured within young follicles exhibited enhanced interaction with somatic cells, more youth-like transcriptome, remodelled metabolome, improved mitochondrial function, and enhanced fidelity of meiotic chromosome segregation. These findings provide the basis for a future follicular somatic cell-based therapy to treat age-associated female infertility.
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Project description:Human ovarian follicles develop a fluid-filled antrum when they reach a diameter of around 250 µm. The antrum contains follicular fluid (FF) composed of secretions from cells in the follicle and from circulation. The composition of FF undergoes massive changes in relation to follicular development. Previously, only FF from large pre-ovulatory follicles aspirated just prior to ovulation, has been analyzed by proteomics; resulting in a high proportion of plasma proteins being detected due to diffusion of proteins through the increasingly leaky basal membrane in larger follicles. We present the first proteomics analysis of FF from normal unstimulated human small antral ovarian follicles (diameter: 3-8mm) identifying the largest number of proteins reported in human FF to date: 2,050 proteins of which 1,151 were identified for the first time in human FF by mass spectrometry. Furthermore, an identified growth factor, midkine, was shown to impact follicular regulatory processes including enhancement of nuclear maturation of immature human oocytes.
2021-09-08 | PXD013344 | Pride
Project description:Direct exposure to physiologically-relevant elevated temperatures during the first half of in vitro maturation heightens cumulus-derived progesterone production, suppresses matrix metallopeptidase 9 secretion, and alters cumulus transcriptome. We hypothesized that heat-induced perturbations in cumulus cells enveloping maturing oocyte may extend to the mural granulosa of the periovulatory follicle in the heat-stressed cow to subsequently follicular fluid proteome. Lactating Holsteins were pharmacologically stimulated to produce a dominant follicle then given GnRH to induce an LH surge. Following GnRH administration, cows were maintained at ~67 temperature humidity index (THI; thermoneutral conditions) or exposed to conditions simulating an acute heat stress event (71 to 86 THI; heat stress for ~12 h). Fluid was aspirated from periovulatory follicle ~16 h after GnRH. Follicular fluid proteome from thermoneutral (n = 5) and hyperthermic (n = 5) cows was evaluated by quantitative tandem mass spectrometry (nano LC-MS/MS). We identified 35 differentially-abundant proteins. Functional annotation revealed numerous immune-related proteins. Subsequent efforts revealed an increase in levels of the proinflammatory mediator bradykinin in follicular fluid (P = 0.0456) but not in serum (P = 0.9319) of hyperthermic cows. Intrafollicular increases in transferrin (negative acute phase protein) in hyperthermic cows (P = 0.0181) coincided with a tendency for levels to be increased in the circulation (P = 0.0683). Nine out of 15 cytokines evaluated were detected in follicular fluid. Heat stress increased intrafollicular IL6 levels (P = 0.0160). Whether hyperthermia-induced changes in the heat-stressed cow’s follicular fluid milieu reflect changes in mural granulosa, cumulus, other cell types secretions, and/or transudative changes from circulation remains unclear. Regardless of origin, heat stress/hyperthermia related changes in the follicular fluid milieu may have an impact on components important for ovulation and competence of the cumulus-oocyte complex contained within the periovulatory follicle
2020-01-13 | PXD015735 | Pride
Project description:Vitrification is a method for long-term biological sample cryopreservation without causing intra- and extra-cellular ice formation. We recently established a novel closed vitrification system to cryopreserve mouse ovarian follicles. Using the 3D alginate hydrogel encapsulated in vitro follicle growth (eIVFG) method, we have demonstrated that compared to freshly-harvested follicles, vitrified follicles have normal follicle and oocyte reproductive outcomes. Our recent study further demonstrated the faithful preservation of molecular signatures of follicle-stimulating hormone (FSH)-stimulated follicle maturation in vitrified follicles. However, it is unknown whether ovulation, another crucial gonadotropin-dependent follicular event, and involved ovulatory gene regulatory pathways are well conserved in vitrified follicles. Fresh and vitrified follicles grown for 8 days by eIVFG were collected at 0, 1, 4 and 8-hour post human chorionic gonadotropin (hCG) treatment for the single-follicle RNA sequencing. Principal component analysis (PCA) and Pearson’s correlation analysis revealed that vitrified follicles have similar transcriptomic profiles to fresh follicles. Furthermore, the expression of several genes essential for ovulation were comparable between vitrified and fresh follicles. In summary, these results demonstrate that our closed vitrification system preserves follicular transcriptomic dynamics during ex vivo ovulation. Together with our previous findings that vitrification preserves FSH-stimulated follicle maturation, the integration of vitrification of immature follicles and eIVFG has a great potential to serve as an additional fertilization preservation approach for young cancer patients and endangerers species. Moreover, follicle vitrification enables a high-content ovarian follicle biobank, which can greatly improve the throughput of eIVFG for studying ovulation biology, anovulatory disease, toxicology, and novel contraceptive drug development targeting ovulation.
2023-09-20 | GSE227091 | GEO
Project description:The composition of follicular fluid reflects crucial paracrine signalling between granulosa- and theca cells and the oocyte. Dynamic changes in the protein composition of human follicular fluid across multiple time points in the period where final meiotic maturation and release of the oocyte take place are previously undescribed. Twenty-five women undergoing IVF- or ICSI treatment in a standard antagonist protocol with agonist ovulation trigger were included in this prospective cohort study. From each patient one follicle was aspirated by transvaginal ultrasound guided puncture at one of five specific time points either before ovulation induction (T=0) or 12-, 17-, 32- or 36 hours after ovulation induction (five patients/time point). Proteomics was carried out by liquid chromatography-mass spectrometry. In total, 400 proteins were identified (FDR<0.05) and 30 were significantly regulated across time points (one-way ANOVA, adjusted p<0.05). Compared to compiled human plasma proteome sets, 47 proteins were unique to follicular fluid. Enriched biological functions among differentially expressed proteins included immune functions, wound healing and functions related to blood coagulation (FDR<0.02). The most profound changes occurred shortly after ovulation induction. We confirmed parallel protein expression to known granulosa cell mRNA changes and described many hitherto unknown protein expression profiles during ovulation. Thus, the study endorsed important biological functions of some proteins and suggested additional proteins, which may be crucial to intrafollicular signalling and oocyte competence that should be further investigated.
2025-02-06 | MSV000097065 | MassIVE
Project description:Vitrification is increasingly used to cryopreserve gametes and embryos in assisted reproductive technology (ART). Our prior research demonstrates that vitrification preserves the viability and functionality of ovarian follicles. However, its impact on follicle-enclosed oocyte remains unknown. The current study investigates whether vitrification, combined with a 3D encapsulated in vitro follicle growth (eIVFG) system, maintains oocyte transcriptome during in vitro follicle development and oocyte maturation. Immature mouse preantral follicles were vitrified and cultured in eIVFG for 8 days to grow to the preovulatory stage, followed with the induction of ovulation and oocyte maturation on day 9, with fresh follicles as the control. Oocytes at germinal vesicle (GV) stage from grown preovulatory follicles on day 8 and oocytes at metaphase II (MII) upon ovulation on day 9 were collected for single-oocyte Smart-Seq2 RNA sequencing analysis. The principal component analysis (PCA) separated GV and MII oocytes into two distinct clusters, but oocytes from fresh and vitrified follicles were largely overlapped. Differential gene expression (DEG) analysis revealed that GV or MII oocytes from fresh and vitrified follicles had comparable expression of maternal effect genes and other genes related to oocyte meiotic and developmental competence. There was a significant transcriptomic change during the GV-to-MII transition. Gene ontology (GO) and KEGG analysis identified DEGs between GV and MII oocytes related to cell cycle, RNA processing, mitochondria, and ribosome. In summary, our study demonstrates that vitrification preserves oocyte transcriptome during in vitro follicle development and oocyte maturation, supporting its potential in fertility preservation. Moreover, our single-oocyte RNA sequencing analysis identifies key DEGs upon GV-to-MII transition, indicating their potential functions in underpinning oocyte meiotic and developmental competence.
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Project description:Follicles of polycystic ovaries (PCO) often become arrested in early antral stages at around 3 to 11 mm in diameter. The condition disturbs dominant follicle selection and may result in altered ovulation and anovulation. During the growth and development of human follicles, the follicular fluid (FF) constitutes the avascular microenvironment in which the oocyte develops and acts as a vehicle for hormone signaling between cues from circulation and follicular cells. Previous proteomics studies performed on FF from women with polycystic ovarian syndrome (PCOS) have revealed information on the protein changes associated with the pathophysiology of this disorder. However, these studies have been conducted on FF samples obtained in connection with oocyte pick-up during ovarian stimulation right at the time of ovulation and are limited to follicular conditions during the follicular phase of the menstrual cycle. This study aimed to detect proteomic alterations in FF from human small antral follicles (hSAF) obtained from women with PCO as compared to normal women.
2022-04-07 | PXD031485 | Pride
Project description:The composition of follicular fluid reflects crucial paracrine signalling between granulosa- and theca cells and the oocyte. Dynamic changes in the protein composition of human follicular fluid across multiple time points in the period where final meiotic maturation and release of the oocyte take place are previously undescribed. Twenty-five women undergoing IVF- or ICSI treatment in a standard antagonist protocol with agonist ovulation trigger were included in this prospective cohort study. From each patient one follicle was aspirated by transvaginal ultrasound guided puncture at one of five specific time points either before ovulation induction (T=0) or 12-, 17-, 32- or 36 hours after ovulation induction (five patients/time point). Proteomics was carried out by liquid chromatography-mass spectrometry. In total, 400 proteins were identified (FDR<0.05) and 30 were significantly regulated across time points (one-way ANOVA, adjusted p<0.05). Compared to compiled human plasma proteome sets, 47 proteins were unique to follicular fluid. Enriched biological functions among differentially expressed proteins included immune functions, wound healing and functions related to blood coagulation (FDR<0.02). The most profound changes occurred shortly after ovulation induction. We confirmed parallel protein expression to known granulosa cell mRNA changes and described many hitherto unknown protein expression profiles during ovulation. Thus, the study endorsed important biological functions of some proteins and suggested additional proteins, which may be crucial to intrafollicular signalling and oocyte competence that should be further investigated.
2019-07-29 | PXD012561 | Pride
Project description:Oocyte competence for early embryo development relies on intercellular communication between the maturing oocyte and preovulatory follicle. Preovulatory follicle maturity, as indicated by serum estradiol concentration or follicle diameter, has previously been linked to pregnancy, follicular fluid metabolites, cumulus-oocyte metabolism, and oocyte competency for embryo development. Such relationships indicate metabolic and developmental programming of the oocyte based on the preovulatory follicle’s physiological status, but downstream impacts on the molecular signature of blastocysts have not been examined. We hypothesized that supplementing maturing oocytes with follicular fluid originating from preovulatory follicles of greater or lesser maturity would impact the transcriptome of resulting blastocysts and indicate metabolic programming of the embryo that originated from the oocyte’s maturation environment. The objective was to investigate the effect of follicle maturity on metabolic preparation of the oocyte by examining the functional genome of blastocysts originating from oocytes matured in the presence of follicular fluid from preovulatory follicles of greater or lesser maturity. In vitro maturing oocytes were supplemented with follicular fluid collected from preovulatory follicles of greater or lesser maturity. Following identical embryo culture procedures, RNA-sequencing was performed on pools of 2 blastocysts (Greater, n = 12; Lesser, n = 15; all with stage code = 7 and quality code = 1). A total of 12,310 gene transcripts were identified in blastocysts after filtering to remove lowly abundant transcripts. There were 113 transcripts that differed in abundance between blastocysts originating from oocytes matured in greater versus lesser maturity follicular fluid (eFDR < 0.01). Although no pathways were significantly enriched with differentially abundant transcripts, transcriptome profiles suggested improved Wnt/β-catenin signaling, metabolism, and protection from oxidative stress in blastocysts derived from oocytes matured in greater maturity follicular fluid, while unregulated cell growth presented in blastocysts resulting from the lesser follicle maturity treatment.
2024-10-22 | GSE279311 | GEO