Single-Cell Transcriptomics Analysis of Human Small Antral Follicles.
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ABSTRACT:
SUBMITTER: Fan X
PROVIDER: S-EPMC8584910 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The reproductive lifespan in humans is regulated by a delicate cyclical balance between follicular recruitment and atresia in the ovary. The majority of the small antral follicles present in the ovary are progressively lost through atresia without reaching dominance, but this process remains largely underexplored. In our study, we investigated the characteristics of atretic small antral follicles and proposed a classification system based on molecular changes observed in granulosa cells, theca cells, and extracellular matrix deposition. Our findings revealed that atresia spreads in the follicle with wave-like dynamics, initiating away from the cumulus granulosa cells. We also observed an enrichment of CD68+ macrophages in the antrum during the progression of follicular atresia. This work not only provides criteria for classifying three stages of follicular atresia in small antral follicles in the human ovary but also serves as a foundation for understanding follicular degeneration and ultimately preventing or treating premature ovarian failure. Understanding follicular remodeling in the ovary could provide a means to increase the number of usable follicles and delay the depletion of the follicular reserve, increasing the reproductive lifespan.
| S-EPMC10706134 | biostudies-literature
Project description:Study questionIs it possible to identify by mass spectrometry a wider range of proteins and key proteins involved in folliculogenesis and oocyte growth and development by studying follicular fluid (FF) from human small antral follicles (hSAF)?Summary answerThe largest number of proteins currently reported in human FF was identified in this study analysing hSAF where several proteins showed a strong relationship with follicular developmental processes.What is known alreadyProtein composition of human ovarian FF constitutes the microenvironment for oocyte development. Previous proteomics studies have analysed fluids from pre-ovulatory follicles, where large numbers of plasma constituents are transferred through the follicular basal membrane. This attenuates the detection of low abundant proteins, however, the basal membrane of small antral follicles is less permeable, making it possible to detect a large number of proteins, and thereby offering further insights in folliculogenesis.Study design, size, durationProteins in FF from unstimulated hSAF (size 6.1 ± 0.4 mm) were characterised by mass spectrometry, supported by high-throughput and targeted proteomics and bioinformatics. The FF protein profiles from hSAF containing oocytes, capable or not of maturing to metaphase II of the second meiotic division during an IVM (n = 13, from 6 women), were also analysed.Participants/materials, setting, methodsWe collected FF from hSAF of ovaries that had been surgically removed from 31 women (∼28.5 years old) undergoing unilateral ovariectomy for fertility preservation.Main results and the role of chanceIn total, 2461 proteins were identified, of which 1108 identified for the first time in FF. Of the identified proteins, 24 were related to follicular regulatory processes. A total of 35 and 65 proteins were down- and up-regulated, respectively, in fluid from hSAF surrounding oocytes capable of maturing (to MII). We found that changes at the protein level occur already in FF from small antral follicles related to subsequent oocyte maturation.Limitations, reasons for cautionA possible limitation of our study is the uncertainty of the proportion of the sampled follicles that are undergoing atresia. Although the FF samples were carefully aspirated and processed to remove possible contaminants, we cannot ensure the absence of some proteins derived from cellular lysis provoked by technical reasons.Wider implications of the findingsThis study is, to our knowledge, the first proteomics characterisation of FF from hSAF obtained from women in their natural menstrual cycle. We demonstrated that the analysis by mass spectrometry of FF from hSAF allows the identification of a greater number of proteins compared to the results obtained from previous analyses of larger follicles. Significant differences found at the protein level in hSAF fluid could predict the ability of the enclosed oocyte to sustain meiotic resumption. If this can be confirmed in further studies, it demonstrates that the viability of the oocyte is determined early on in follicular development and this may open up new pathways for augmenting or attenuating subsequent oocyte viability in the pre-ovulatory follicle ready to undergo ovulation.Study funding/competing interest(s)The authors thank the financial support from ReproUnion, which is funded by the Interreg V EU programme. No conflict of interest was reported by the authors.Trial registration numberN/A.
| S-EPMC7891813 | biostudies-literature
Project description:Polycystic ovaries (PCO) contain antral follicles that arrest growing around 3-11 mm in diameter, perturbing the dominant follicle's selection and the subsequent ovulatory process. Proteomic alterations of PCO follicular fluid (FF) (i.e., microenvironment in which the oocyte develops until ovulation) have been studied from large follicles in connection with oocyte pickup during ovarian stimulation. The present study aimed to detect proteomic alterations in FF from unstimulated human small antral follicles (hSAF) obtained from PCO. After performing deep-sequencing label-free proteomics on 10 PCO and 10 non-PCO FF samples from unstimulated hSAF (4.6-9.8 mm), 1436 proteins were identified, of which 115 were dysregulated in PCO FF samples. Pathways and processes related to the immune system, inflammation, and oxidative stress appeared to be upregulated in PCO, while extracellular matrix receptors interactions, the collagens-containing extracellular matrix, and the regulation of signaling were downregulated. The secreted proteins SFRP1, THBS4, and C1QC significantly decreased their expression in PCO FF, and this downregulation was suggested to affect future oocyte competence. In conclusion, our study revealed, for the first time, evidence of proteomic alterations occurring in the FF of PCO hSAF that may be related to the dysfunction of follicular growth and subsequent oocyte competence.
| S-EPMC8954146 | biostudies-literature
Project description:Human ovarian folliculogenesis is an highly regulated and complex process. Characterization of follicular cell signatures during this dynamic process is important to understand follicle fate (to grow, become dominant or undergo atresia). The transcriptional signature of human oocytes and granulosa cells (GC) in early-growing and ovulatory follicles have been previously described, however that of oocytes with surrounding GCs in small antral follicles have not been studied yet. Here, we have generated a unique dataset of single-cell transcriptomics (SmartSeq2) consisting of the oocyte with surrounding GCs from several individual (non-dominant) small antral follicles isolated from adult human ovaries. We have identified two main types of (healthy) follicles, with a distinct oocyte and GC signature. Using the CellphoneDB algorithm, we then investigated the bi-directional ligand-receptor interactions regarding the TGFβ/BMP, WNT, NOTCH, and receptor tyrosine kinases (RTK) signaling pathways between oocyte and GCs within each antral follicle type. Our work not only revealed the diversity of small antral follicles but also contributes to fill the gap in mapping the molecular landscape of human folliculogenesis and oogenesis.
2021-10-26 | GSE186504 | GEO
Project description:The predisposition for the initiation of folliculogenesis in mammals including humans is programmed to start at fetal life and continues until reproductive capacity. The follicles grow from a pool of primordial follicles which retain the major functions in the entire reproductive life of a female. Anti-müllerian hormone (AMH), a glycoprotein belonging to the transforming growth factor-beta family, has an inhibitory effect on ovarian follicle development. The key regulatory target genes in primordial follicle development are of paramount importance in reproductive biology of female. A systems biology method was used to find regulatory genes performing critical role in primordial follicle development. A complete in-depth bioinformatics analysis was performed to investigate the changes in transcriptome of preantral to small antral mouse follicles treated for 12 h and 24 h with two different concentrations; 50 and 200 ng/ml of AMH, and thereby identify candidate genes in time and concentration manner. Firstly, we found differentially expressed genes that were time and concentration dependent in response to AMH. The network analysis of these differentially expressed genes provided new candidate genes and pathways associated with inhibitory action of AMH on the primordial follicle development. To further emphasize the function of AMH, the key identified genes' protein-protein docking was analyzed and found the intracellular and extracellular protein-protein interaction. This study elucidates one of the novel mechanisms of AMH involvement in inhibition of ovarian follicle development which may lead to prolong productive life in female.
| S-EPMC6084392 | biostudies-literature
Project description:Anti-Müllerian hormone (AMH) is a member of the TGF-β superfamily produced by follicular granulosa cells (GCs) in women from late gestation to the end of reproductive life. AMH is thought to inhibit aromatase (i.e., CYP19) expression and decrease the conversion of androgens to oestrogens, especially in small antral follicles before dominance is achieved. Thus, AMH acts as a gatekeeper of ovarian steroidogenesis. However, the exact function and processing of AMH has not been fully elucidated. The present study measured and determined AMH isoforms in human follicular fluid (FF) from small antral follicles and in human GCs using four ELISAs, western blot, and immunofluorescence analysis. We evaluated the presence of the following isoforms: full-length AMH precursor (proAMH), cleaved associated AMH (AMHN,C), N-terminal pro-region (AMHN), and active C-terminal (AMHC) AMH. A negative correlation between follicle diameter and the AMH forms was detected. Moreover, western blot analysis detected various AMH forms in both FFs and GCs, which did not match our consensus forms, suggesting an unknown proteolytic processing of AMH. The presence of these new molecular weight isoforms of AMH differs between individual follicles of identical size in the same woman. This study detected several AMH forms in FF and GCs obtained from human small antral follicles, which suggests that intrafollicular processing of AMH is complex and variable. Thus, it may be difficult to develop an antibody-based AMH assay that detects all AMH isoforms. Furthermore, the variability between follicles suggests that designing a recombinant AMH standard will be difficult.
| S-EPMC7961079 | biostudies-literature
Project description:The antral follicle stage plays a crucial role in mammalian oocyte maturation, signifying the final stages of oocyte development and ovulation. This complex process relies on synchronized interactions between oocyte maturation and the proliferation of neighboring granulosa cells. Previous studies have identified two subtypes of granulosa cells in antral follicles: cumulus granulosa cells, located in the inner region, which surround and support the oocyte, and mural granulosa cells, present in the outer layers, which provide mechanical support to the follicular wall and possess steroidogenic functions. Despite the wealth of molecular data generated by these studies, many fundamental questions regarding key developmental events, granulosa cell heterogeneity, functional annotation, and the intricate relationship between somatic cells and oocytes still lack detailed, single-cell resolution-level investigations. In this study, we isolated follicular cells from porcine antral follicles and conducted scRNA-seq to analyze the single-cell transcriptomes of these cells. By identifying and sub-clustering ovarian cells, such as mural granulosa cells and cumulus granulosa cells, we elucidated the heterogeneity of granulosa cells in pigs.
2023-10-24 | GSE237134 | GEO
Project description:Neonicotinoid insecticides are synthetic nicotine derivatives that have high affinity for invertebrate nicotine receptors and low affinity for mammalian nicotine receptors. However, imidacloprid (IMI), the most commonly used neonicotinoid, can be bioactivated by the liver in mammals to desnitro-imidacloprid, an intermediate metabolite that effectively binds and activates mammalian receptors. However, it is not known if other tissues such as the ovaries can metabolize IMI. Thus, the present study tested the hypothesis that ovarian antral follicles metabolize and bioactivate IMI. Antral follicles were dissected from the ovaries of CD-1 mice and cultured in media containing dimethyl sulfoxide or IMI (0.2-200 µg/ml) for 48 and 96 h. Media were subjected to liquid chromatography-mass spectrometry for detection of phase I IMI metabolites. Follicles from the cultures were used for gene expression analysis of metabolic enzymes associated with IMI metabolism. All IMI metabolites were detected at 48 and 96 h. Oxidized IMI intermediates were detected in media from cultured follicles, but not environmental controls. Reduced IMI intermediates were detected in media from cultured follicles and the environmental controls. At 48 h, IMI did not affect expression of any metabolic enzymes compared with control. At 96 h, IMI induced Cyp2e1 and Cyp4f18 compared with control. These data indicate that mouse ovarian follicles metabolize IMI and that IMI induces ovarian Cyp expression over time.
| S-EPMC10682976 | biostudies-literature
Project description:In studies using isolated ovarian granulosa and thecal cells it is important to assess the degree of cross contamination. Marker genes commonly used for granulosa cells include FSHR, CYP19A1 and AMH while CYP17A1 and INSL3 are used for thecal cells. To increase the number of marker genes available we compared expression microarray data from isolated theca interna with that from granulosa cells of bovine small (n = 10 for both theca and granulosa cells; 3-5 mm) and large (n = 4 for both theca and granulosa cells, > 9 mm) antral follicles. Validation was conducted by qRT-PCR analyses. Known markers such as CYP19A1, FSHR and NR5A2 and another 11 genes (LOC404103, MGARP, GLDC, CHST8, CSN2, GPX3, SLC35G1, CA8, CLGN, FAM78A, SLC16A3) were common to the lists of the 50 most up regulated genes in granulosa cells from both follicle sizes. The expression in theca interna was more consistent than in granulosa cells between the two follicle sizes. Many genes up regulated in theca interna were common to both sizes of follicles (MGP, DCN, ASPN, ALDH1A1, COL1A2, FN1, COL3A1, OGN, APOD, COL5A2, IGF2, NID1, LHFP, ACTA2, DUSP12, ACTG2, SPARCL1, FILIP1L, EGFLAM, ADAMDEC1, HPGD, COL12A1, FBLN5, RAMP2, COL15A1, PLK2, COL6A3, LOXL1, RARRES1, FLI1, LAMA2). Many of these were stromal extracellular matrix genes. MGARP, GLDC, CHST8, GPX3 were identified as new potential markers for granulosa cells, while FBLN5, OGN, RAMP2 were significantly elevated in the theca interna.
| S-EPMC4361622 | biostudies-literature
Project description:The theca interna layer of the ovarian follicle forms during the antral stage of follicle development and lies adjacent to and directly outside the follicular basal lamina. It supplies androgens and communicates with the granulosa cells and the oocyte by extracellular signaling. To better understand developmental changes in the theca interna, we undertook transcriptome profiling of the theca interna from small (3-5 mm, n?=?10) and large (9-12 mm, n?=?5) healthy antral bovine follicles, representing a calculated >7-fold increase in the amount of thecal tissue. Principal Component Analysis and hierarchical classification of the signal intensity plots for the arrays showed no clustering of the theca interna samples into groups depending on follicle size or subcategories of small follicles. From the over 23,000 probe sets analysed, only 76 were differentially expressed between large and small healthy follicles. Some of the differentially expressed genes were associated with processes such as myoblast differentiation, protein ubiquitination, nitric oxide and transforming growth factor ? signaling. The most significant pathway affected from our analyses was found to be Wnt signaling, which was suppressed in large follicles via down-regulation of WNT2B and up-regulation of the inhibitor FRZB. These changes in the transcriptional profile could have been due to changes in cellular function or alternatively since the theca interna is composed of a number of different cell types it could have been due to any systematic change in the volume density of any particular cell type. However, our study suggests that the transcriptional profile of the theca interna is relatively stable during antral follicle development unlike that of granulosa cells observed previously. Thus both the cellular composition and cellular behavior of the theca interna and its contribution to follicular development appear to be relatively constant throughout the follicle growth phase examined.
| S-EPMC4022581 | biostudies-literature