Chromatin Accessibility and Transcriptomic Alterations in Murine Ovarian Granulosa Cells upon Deoxynivalenol Exposure.

Hairui Fan,Wenbin Bao,Chao Xu,Zhengchang Wu,Zhanshi Ren,Shenglong Wu,Ming-An Sun,Zia Ur Rehman,Haifei Wang

doi:10.3390/cells10112818

Hairui Fan, Wenbin Bao + Show 7 more

Open Access

https://doi.org/10.3390/cells10112818

Copy DOI

Abstract

Deoxynivalenol (DON) is a common environmental toxin that is secreted by fusarium fungi that frequently contaminates feedstuff and food. While the detrimental effects of DON on human and animal reproductive systems have been well recognized, the underlying mechanism remains poorly understood. Ovarian granulosa cells (GCs), which surround oocytes, are crucial for regulating oocyte development, mainly through the secretion of hormones such as estrogen and progesterone. Using an in vitro model of murine GCs, we characterized the cytotoxic effects of DON and profiled genome-wide chromatin accessibility and transcriptomic alterations after DON exposure. Our results suggest that DON can induce decreased viability and growth, increased apoptosis rate, and disrupted hormone secretion. In total, 2533 differentially accessible loci and 2675 differentially expressed genes were identified that were associated with Hippo, Wnt, steroid biosynthesis, sulfur metabolism, and inflammation-related pathways. DON-induced genes usually have a concurrently increased occupancy of active histone modifications H3K4me3 and H3K27ac in their promoters. Integrative analyses identified 35 putative directly affected genes including Adrb2 and Fshr, which are key regulators of follicular growth, and revealed that regions with increased chromatin accessibility are enriched with the binding motifs for NR5A1 and NR5A2, which are important for GCs. Moreover, DON-induced inflammatory response is due to the activation of the NF-κB and MAPK signaling pathways. Overall, our results provide novel insights into the regulatory elements, genes, and key pathways underlying the response of ovarian GCs to DON cytotoxicity.

Highlights

Given the important role of granulosa cells (GCs) in hormone secretion, we determined the effect of DON on the secretion levels of estrogen and progesterone, which are essential for follicular growth
H3K4me3 and H3K27ac upon DON exposure (Figure 5). These results indicate that the alterations of gene expression, chromatin accessibility, and histone modifications in ovarian GCs upon DON exposure are closely correlated
We established an in vitro model of mouse ovarian GCs to investigate the DON-induced toxicity effects and cellular response and performed ATAC-Seq and RNA-Seq to characterize the alterations of chromatin accessibility and the transcriptomic landscape upon DON exposure

Summary

Introduction

During the development of follicles in the mammalian ovary, layers of granulosa cells (GCs) surround the oocyte, which maintain the status of cumulus–oocyte complexes (COCs) for a period. Ovarian GCs play a key role in regulating the development of oocytes through the special structure of paracrine and junctional interactions between GCs and oocytes [1]. GCs regulate follicular selection and atresia [2], provide substrate to the growing oocytes [3], and affect follicular selection and atresia [2]. GCs are the major source for several types of steroid hormones, such as estrogen and progesterone, which are essential for follicle development [4,5]. Given the central role of GCs in ovaries, in vitro cultured GCs serve as a widely used model to study female reproduction

Methods

Results

Conclusion