Dataset Information

Epigenetic effects of Bisphenol A on granulosa cells of mouse follicles during in vitro culture: An experimental study.

ABSTRACT:

Background

Bisphenol A (BPA), a synthetic endocrine-disrupting chemical, is a reproductive toxicant. Granulosa cells have significant roles in follicle development, and KIT ligand (KITL) and Anti-Müllerian hormone (AMH) are essential biomolecules produced by them during folliculogenesis.

Objective

Due to the widespread use of BPA and its potential epigenetic effects, this study examined the impact of BPA on promoter methylation of amh and kitl genes in mouse granulosa cells.

Materials and methods

Preantral follicles were isolated from ovaries of immature mice and cultured for eight days. Then, follicles were treated with 50 and 100 ?M of BPA, and 0.01% (v/v) ethanol for 24 and 72 hr. Growth and degeneration of follicles and antrum formation were analyzed. The granulosa cells were isolated mechanically, and their extracted DNA was treated with sodium bisulfite. The promoter regions of the amh and kitl were analyzed with PCR and sequencing.

Results

BPA did not change follicle survival and antrum formation significantly (p = 0.41). However, the culture in the presence of 100 ?M BPA had an inhibitory effect on growth. Before BPA treatment, the CpG of the kitl and amh promoters were unmethylated and partially methylated, respectively. While the percent of 5mC in the amh promoter reduced at 100 ?M of BPA, it did not alter the kitl promoter methylation.

Conclusion

BPA at higher concentrations has an inhibitory effect on follicle growth. Moreover, it seems that the epigenetic impact of BPA restricts to the demethylation of CpG sites.

SUBMITTER: Khaghani AJ

PROVIDER: S-EPMC7922291 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature

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Publications

Epigenetic effects of Bisphenol A on granulosa cells of mouse follicles during in vitro culture: An experimental study.

Khaghani Aylin Jamali AJ Farrokh Parisa P Zavareh Saeed S

International journal of reproductive biomedicine 20210221 2

<h4>Background</h4>Bisphenol A (BPA), a synthetic endocrine-disrupting chemical, is a reproductive toxicant. Granulosa cells have significant roles in follicle development, and KIT ligand (KITL) and Anti-Müllerian hormone (AMH) are essential biomolecules produced by them during folliculogenesis.<h4>Objective</h4>Due to the widespread use of BPA and its potential epigenetic effects, this study examined the impact of BPA on promoter methylation of <i>amh</i> and <i>kitl</i> genes in mouse granulos ...[more]

PMID: 33718757

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Project description:BACKGROUND: The major function of the ovary is to produce oocytes for fertilisation. Oocytes mature in follicles surrounded by nurturing granulosa cells and all are enclosed by a basal lamina. During growth, granulosa cells replicate and a large fluid-filled cavity (the antrum) develops in the centre. Only follicles that have enlarged to over 10 mm can ovulate in cows. In mammals, the number of primordial follicles far exceeds the numbers that ever ovulate and atresia or regression of follicles is a mechanism to regulate the number of oocytes ovulated and to contribute to the timing of ovulation. To better understand the molecular basis of follicular atresia, we undertook transcriptome profiling of granulosa cells from healthy (n = 10) and atretic (n = 5) bovine follicles at early antral stages (< 5 mm). RESULTS: Principal Component Analysis (PCA) and hierarchical classification of the signal intensity plots for the arrays showed primary clustering into two groups, healthy and atretic. These analyses and size-frequency plots of coefficients of variation of signal intensities revealed that the healthy follicles were more heterogeneous. Examining the differentially-expressed genes the most significantly affected functions in atretic follicles were cell death, organ development, tissue development and embryonic development. The overall processes influenced by transcription factor gene TP53 were predicted to be activated, whereas those of MYC were inhibited on the basis of known interactions with the genes in our dataset. The top ranked canonical pathway contained signalling molecules common to various inflammatory/fibrotic pathways such as the transforming growth factor-? and tumour necrosis factor-? pathways. The two most significant networks also reflect this pattern of tissue remodelling/fibrosis gene expression. These networks also contain molecules which are present in the canonical pathways of hepatic fibrosis/hepatic stellate cell activation and transforming growth factor-? signalling and were up regulated. CONCLUSIONS: Small healthy antral follicles, which have a number of growth outcomes, exhibit greater variability in gene expression, particularly in genes associated with cell division and other growth-related functions. Atresia, on the other hand, not only involves cell death but clearly is an active process similar to wound healing.

Project description:STUDY QUESTIONDoes bisphenol-A (BPA) affect gene expression in human membrana granulosa cells (MGC)?SUMMARY ANSWERIn vitro, short exposure to supra-physiological concentrations of BPA alters human MGC gene expression.WHAT IS KNOWN ALREADYExposure to BPA may interfere with reproductive endocrine signaling. In vitro studies, mostly in animal models, have shown an inverse correlation between exposure to BPA and follicular growth, meiosis, and steroid hormone production in granulosa cells.STUDY DESIGN, SIZE, DURATIONPrimary cultures of MGC obtained from 24 patients undergoing IVF (for PGD, male factor infertility or unexplained infertility) were exposed to various concentrations of BPA (0, 0.02, 0.2, 2 or 20 µg/ml) for 48 h.PARTICIPANTS/MATERIALS, SETTING, METHODSThe study was conducted in a university-affiliated hospital. Microarray analysis was used to identify genes exhibiting expression changes following BPA exposure. Genes significantly altered were identified based on changes greater than 2-fold relative to the control group (not treated by BPA) and a Student's t-test P-value <0.05. Statistical significance was adjusted for multiple comparisons using the Benjamini-Hochberg method. Alterations in the expression of genes that are involved in the enriched functional annotations altered by BPA at the concentration of 20 µg/ml were confirmed by real-time PCR.MAIN RESULTS AND THE ROLE OF CHANCEA distinct pattern of gene expression was observed in primary cultures of MGC exposed to the highest BPA concentration compared with untreated cells. We identified 652 genes that exhibited at least 2-fold differences in expression after BPA exposure (all P < 0.05 versus untreated). These genes were significantly enriched for annotations related to cell cycle progression, segregation of chromosomes, steroid metabolism, apoptosis, lipid synthesis, oocyte maturation and chromosomal alignment. No significant changes in gene expression were found at the lower doses of BPA most relevant to human exposure.LARGE SCALE DATAN/A.LIMITATIONS, REASONS FOR CAUTIONHuman exposure to BPA in vivo occurs over long periods of time. In this in vitro model, cells were exposed to the chemical for 48 h only. Thus, the effects of BPA on the human follicle might be underestimated.WIDER IMPLICATIONS OF THE FINDINGSAs BPA exposure is ubiquitous, understanding the effects of the chemical on the ovary, specifically in women of reproductive age, has public health significance. The clinical evidence to date points to an association between BPA exposure and impaired IVF outcome, although not all studies have shown negative effects. Our study adds valuable mechanistic information showing that exposure to BPA alters granulosa cell gene expression at high and supra-physiological doses.STUDY FUNDING/COMPETING INTERESTSThis study was supported by grant number 1936/12 from the ISF. The authors have nothing to disclose.

Dataset Information

Epigenetic effects of Bisphenol A on granulosa cells of mouse follicles during in vitro culture: An experimental study.

Background

Objective

Materials and methods

Results

Conclusion

Publications

Epigenetic effects of Bisphenol A on granulosa cells of mouse follicles during in vitro culture: An experimental study.

Similar Datasets

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