NRF2-mediated signaling is a master regulator of transcription factors in bovine granulosa cells under oxidative stress condition

Abstract

Transcription factors (TFs) are known to be involved in regulating the expression of several classes of genes during folliculogenesis. However, the regulatory role of TFs during oxidative stress (OS) is not fully understood. The current study was aimed to investigate the regulation of the TFs in bovine granulosa cells (bGCs) during exposure to OS induced by H2O2 in vitro. For this, bGCs derived from ovarian follicles were cultured in vitro till their confluency and then treated with H2O2 for 40 min. Twenty-four hours later, cells were subjected to various phenotypic and gene expression analyses for genes related to TFs, endoplasmic reticulum stress, apoptosis, cell proliferation, and differentiation markers. The bGCs exhibited higher reactive oxygen species accumulation, DNA fragmentation, and endoplasmic reticulum stress accompanied by reduction of mitochondrial activity after exposure to OS. In addition, higher lipid accumulation and lower cell proliferation were noticed in H2O2-challenged cells. The mRNA level of TFs including NRF2, E2F1, KLF6, KLF9, FOS, SREBF1, SREBF2, and NOTCH1 was increased in H2O2-treated cells compared with non-treated controls. However, the expression level of KLF4 and its downstream gene, CCNB1, were downregulated in the H2O2-challenged group. Moreover, targeted inhibition of NRF2 using small interference RNA resulted in reduced expression of KLF9, FOS, SREBF2, and NOTCH1 genes, while the expression of KLF4 was upregulated. Taken together, bovine granulosa cells exposed to OS exhibited differential expression of various transcription factors, which are mediated by the NRF2 signaling pathway.

NRF2 attenuation aggravates detrimental consequences of metabolic stress on cultured porcine parthenote embryos

“…This finding indicates that NRF2 plays a crucial role in regulating the embryo's response to adverse culture conditions. Previous studies involving bovine granulosa cells and embryos have also suggested that NRF2 function is primarily required under stressful conditions 33 , 37 . Moreover, various molecules with protective roles in cultured cells, including retinal epithelial cells 57 and podocytes 58 , appears to exert their effects through the activation of NRF2, although the underlying molecular pathways have yet to be fully characterized.…”

“…NRF2 is a master regulator of oxidative balance and plays various cellular roles in regulating redox homeostasis, mitochondrial function, oxidative phosphorylation, ATP production, and fatty acid oxidation 32 . NRF2 has been shown to regulate oxidative stress in granulosa cells under stressful conditions 33 , and this function may involve interactions with miRNAs 34 . Furthermore, NRF2 induces peroxisomal activities in porcine oocytes and embryos 31 , 35 .…”

Construction of an oxidative stress-associated genes signature in breast cancer by machine learning algorithms

“…[18][19][20] Nrf2 is a transcription factor and when cells are subjected to oxidative stress, Nrf2 is transferred from the cytoplasm to the nucleus and binds to antioxidant response element to promote the transcription of a series of antioxidant genes, such as the GR and SOD genes, which enhances the antioxidant capacity of cells. 21 Under oxidative stress conditions, FOXO protein activity is activated and promotes the expression of a series of antioxidant response genes, such as SOD and glutathione peroxidase (GPX). 22 In breast cancer cells, mitochondrial signal transducer and activator of transcription 3 plays a role in regulating cellular redox balance by regulating antioxidant gene expression.…”

Bisphenol A and bisphenol S both disrupt ovine granulosa cell steroidogenesis but through different molecular pathways

“…NOTCH1 is a DEG in the BPA versus BPS comparison. In the bovine ovary, the NOTCH signalling pathway is involved in follicular development, steroidogenesis and regression of the corpus luteum [64]. This signalling pathway has already been reported to be impacted in the presence of BPA, disrupting juxtacrine communication in rat testes [79] and steroidogenesis in foetal testes in vitro [80].…”

“…Their effects depend on their concentration and affinity for each receptor, a factor that can partially explain their non-linear effect [63]. Only a few DEG were common between treatment with BPA or BPS and G1, including STAR , a cytoplasmic cholesterol transporter involved in steroidogenesis [3]; SREBF1, a transcription factor involved in the regulation of the biosynthesis of fatty acids and cholesterol [64]; and SPRY2, a negative regulator of tyrosine kinase receptor activity. The mRNA level of these genes in GC was correlated negatively with oocyte developmental competence in bovine [65].…”