scholarly journals Bisphenol A and 17α-ethinylestradiol-induced transgenerational gene expression differences in the brain–pituitary–testis axis of medaka, Oryzias latipes†

2020 ◽  
Vol 103 (6) ◽  
pp. 1324-1335
Author(s):  
Albert J Thayil ◽  
Xuegeng Wang ◽  
Pooja Bhandari ◽  
Frederick S vom Saal ◽  
Donald E Tillitt ◽  
...  

Abstract Endocrine disrupting chemicals (EDCs), such as bisphenol A (BPA) and 17α-ethinylestradiol (EE2), can have far reaching health effects, including transgenerational abnormalities in offspring that never directly contacted either chemical. We previously reported reduced fertilization rates and embryo survival at F2 and F3 generations caused by 7-day embryonic exposure (F0) to 100 μg/L BPA or 0.05 μg/L EE2 in medaka. Crossbreeding of fish in F2 generation indicated subfertility in males. To further understand the mechanisms underlying BPA or EE2-induced adult onset and transgenerational reproductive defects in males, the present study examined the expression of genes regulating the brain–pituitary–testis (BPT) axis in the same F0 and F2 generation male medaka. Embryonic exposure to BPA or EE2 led to hyperactivation of brain and pituitary genes, which are actively involved in reproduction in adulthood of the F0 generation male fish, and some of these F0 effects continued to the F2 generation (transgenerational effects). Particularly, the F2 generation inherited the hyperactivated state of expression for kisspeptin (kiss1 and kiss2) and their receptors (kiss1r and kiss2r), and gnrh and gnrh receptors. At F2 generation, expression of DNA methyltransferase 1 (dnmt1) decreased in brain of the BPA treatment lineage, while EE2 treatment lineage showed increased dnmt3bb expression. Global hypomethylation pattern was observed in the testis of both F0 and F2 generation fish. Taken together, these results demonstrated that BPA or EE2-induced transgenerational reproductive impairment in the F2 generation was associated with alterations of reproductive gene expression in brain and testis and global DNA methylation in testis.

2019 ◽  
Vol 31 (3) ◽  
pp. 509 ◽  
Author(s):  
Minli Yu ◽  
Dongfeng Li ◽  
Wanyan Cao ◽  
Xiaolu Chen ◽  
Wenxing Du

Ten–eleven translocation 1 (Tet1) is involved in DNA demethylation in primordial germ cells (PGCs); however, the precise regulatory mechanism remains unclear. In the present study the dynamics of 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) in developing PGCs and the role of Tet1 in PGC demethylation were analysed. Results show that 5mC levels dropped significantly after embryonic Day 4 (E4) and 5hmC levels increased reaching a peak at E5–E5.5. Interestingly, TET1 protein was highly expressed during E5 to E5.5, which showed a consistent trend with 5hmC. The expression of pluripotency-associated genes (Nanog, PouV and SRY-box 2 (Sox2)) and germ cell-specific genes (caveolin 1 (Cav1), piwi-like RNA-mediated gene silencing 1 (Piwi1) and deleted in azoospermia-like (Dazl)) was upregulated after E5, whereas the expression of genes from the DNA methyltransferase family was decreased. Moreover, the Dazl gene was highly methylated in early PGCs and then gradually hypomethylated. Knockdown of Tet1 showed impaired survival and proliferation of PGCs, as well as increased 5mC levels and reduced 5hmC levels. Further analysis showed that knockdown of Tet1 led to elevated DNA methylation levels of Dazl and downregulated gene expression including Dazl. Thus, this study reveals the dynamic epigenetic reprogramming of chicken PGCs invivo and the molecular mechanism of Tet1 in regulating genomic DNA demethylation and hypomethylation of Dazl during PGC development.


2000 ◽  
Vol 14 (3) ◽  
pp. 421-428 ◽  
Author(s):  
Hisashi Masuyama ◽  
Yuji Hiramatsu ◽  
Mamoru Kunitomi ◽  
Takafumi Kudo ◽  
Paul N. MacDonald

Abstract Recently, Pregnane X receptor (PXR), a new member of the nuclear receptor superfamily, was shown to mediate the effects of several steroid hormones, such as progesterone, glucocorticoid, pregnenolone, and xenobiotics on cytochrome P450 3A genes (CYP3A) through the specific DNA sequence for CYP3A, suggesting that PXR may play a role in steroid hormone metabolism. In this paper, we demonstrated that phthalic acid and nonylphenol, endocrine-disrupting chemicals (EDCs), stimulated PXR-mediated transcription at concentrations comparable to those at which they activate estrogen receptor-mediated transcription using a transient reporter gene expression assay in COS-7 cells. However, bisphenol A, another EDC, had no effect on PXR-mediated transcription, although this chemical significantly enhanced ER-mediated transcription. In the yeast two-hybrid protein interaction assay, PXR interacted with two nuclear receptor coactivator proteins, steroid hormone receptor coactivator-1 and receptor interacting protein 140, in the presence of phthalic acid or nonylphenol. Thus, EDC-occupied PXR may regulate its specific gene expression through the receptor-coactivator interaction. In contrast, these EDCs had no effect on the interaction between PXR and suppressor for gal 1, a component of proteasome. Finally, the expression of CYP3A1 mRNA in the liver of rats exposed to phthalic acid or nonylphenol markedly increased compared with that in rats treated with estradiol, bisphenol A, or ethanol as assessed by competitive RT-PCR. These data suggest that EDCs may affect endocrine functions by altering steroid hormone metabolism through PXR.


2020 ◽  
Author(s):  
Brenda Cabrera-Mendoza

Despite individuals with substance use disorder (SUD) have a high suicide risk, most of gene expression studies in suicide have excluded individuals with this disorder. Thus, little is known about the gene expression profile in suicides with SUD. The identification of altered biological processes in the brain of suicides with SUD is crucial in the comprehension of the SUD and suicidal behavior comorbidity. This dissertation describes the evaluation of gene expression differences in the dorsolateral prefrontal cortex of suicides and non-suicides with and without SUD.Sixty-six brain tissue samples were collected and classified in the following groups: i) 23 suicides with SUD, ii) 20 suicides without SUD, iii) 9 non-suicides with SUD and iv) 14 non-suicides without SUD. The results of this study suggest that suicides with SUD have a gene expression profile in the prefrontal cortex different from that of individuals with only one of these conditions, presenting differences in the expression of genes involved in cell proliferation and glutamatergic neurotransmission.We performed a re-analysis of the gene expression data of 38 suicides focused on dual diagnosis and suicide. Dual diagnosis is the concurrence of at least one SUD and one or more mental disorders in a given individual. Although this comorbidity is highly prevalent and is associated with adverse clinical outcomes, its neurobiology has not been elucidated. In addition, patients with dual pathology have a higher suicide risk compared to patients with only one disorder.The objective of this re-analysis was to evaluate the differences in the gene expression profile in the prefrontal cortex of suicides with dual pathology compared to suicides with a single disorder. Our results suggest an alteration in the expression of genes involved in glutamatergic neurotransmission, GABAergic neurotransmission and neurogenesis in suicides with dual diagnosis compared to suicides with a single disorder and suicides without mental comorbidities.The observed differences in gene expression in the prefrontal cortex between suicides with and without SUD, as well as suicides with dual diagnosis and a single disorder may contribute to the phenotypic and clinical discrepancies observed among these patients. The identification of molecular characteristics in the brain of individuals with suicidal behavior and psychiatric comorbidities will allow the design of preventive and therapeutic measures aimed at the adequate treatment of each comorbidity.


2021 ◽  
Author(s):  
Weikang Cai ◽  
Xuemei Zhang ◽  
Thiago M. Batista ◽  
Rubén García-Martín ◽  
Samir Softic ◽  
...  

The brain is now recognized as an insulin sensitive tissue, however, the role of changing insulin concentrations in the peripheral circulation on gene expression in the brain is largely unknown. Here we perform hyperinsulinemic-euglycemic clamp on 3-month-old male C57BL/6 mice for 3 hours. We show that increases in peripheral insulin within the physiological range regulate expression of a broad network of gene expression in the brain compared with saline-infused controls. Insulin regulates distinct pathways in the hypothalamus, hippocampus and nucleus accumbens. Insulin shows its most robust effect in the hypothalamus and regulates multiple genes involved in neurotransmission, including up-regulating expression of multiple subunits of GABA-A receptors, Na<sup>+</sup> and K<sup>+</sup> channels, and SNARE proteins; differentially modulating glutamate receptors; and suppressing multiple neuropeptides. Insulin also strongly modulates metabolic genes in the hypothalamus, suppressing genes in the glycolysis and pentose phosphate pathways, while increasing expression of genes regulating pyruvate dehydrogenase and long-chain fatty acyl-CoA and cholesterol biosynthesis, thereby rerouting of carbon substrates from glucose metabolism to lipid metabolism required for the biogenesis of membranes for neuronal and glial function and synaptic remodeling. Furthermore, based on the transcriptional signatures, these changes in gene expression involve neurons, astrocytes, oligodendrocytes, microglia and endothelial cells. Thus, peripheral insulin acutely and potently regulates expression of a broad network of genes involved in neurotransmission and brain metabolism. Dysregulation of these pathways could have dramatic effects in normal physiology and diabetes.


2021 ◽  
Vol 22 (4) ◽  
pp. 2125
Author(s):  
Marta Lombó ◽  
María Paz Herráez

Parental exposure to bisphenol A (BPA) has been linked to a greater incidence of congenital diseases. We have demonstrated that BPA induces in zebrafish males an increase in the acetylation of sperm histones that is transmitted to the blastomeres of the unexposed progeny. This work is aimed to determine whether histone hyperacetylation promoted by paternal exposure to BPA is the molecular mechanism underlying the cardiogenesis impairment in the descendants. Zebrafish males were exposed to 100 and 2000 µg/L BPA during early spermatogenesis and mated with non-exposed females. We analyzed in the progeny the expression of genes involved in cardiogenesis and the epigenetic profile. Once the histone hyperacetylation was confirmed, treatment with epigallocatechin gallate (EGCG), an inhibitor of histone acetyltransferases, was assayed on F1 embryos. Embryos from males exposed to 2000 µg/L BPA overexpressed the transcription factor hand2 and the receptor esr2b, showing their own promoters—as well as that of kat6a—an enrichment in H3K9ac. In embryos treated with EGCG, both gene expression and histone acetylation (global and specific) returned to basal levels, and the phenotype was recovered. As shown by the results, the histone hyperacetylated landscape promoted by BPA in the sperm alters the chromatin structure of the progeny, leading to the overexpression of the histone acetyltransferase and genes involved in cardiogenesis.


2021 ◽  
Author(s):  
Weikang Cai ◽  
Xuemei Zhang ◽  
Thiago M. Batista ◽  
Rubén García-Martín ◽  
Samir Softic ◽  
...  

The brain is now recognized as an insulin sensitive tissue, however, the role of changing insulin concentrations in the peripheral circulation on gene expression in the brain is largely unknown. Here we perform hyperinsulinemic-euglycemic clamp on 3-month-old male C57BL/6 mice for 3 hours. We show that increases in peripheral insulin within the physiological range regulate expression of a broad network of gene expression in the brain compared with saline-infused controls. Insulin regulates distinct pathways in the hypothalamus, hippocampus and nucleus accumbens. Insulin shows its most robust effect in the hypothalamus and regulates multiple genes involved in neurotransmission, including up-regulating expression of multiple subunits of GABA-A receptors, Na<sup>+</sup> and K<sup>+</sup> channels, and SNARE proteins; differentially modulating glutamate receptors; and suppressing multiple neuropeptides. Insulin also strongly modulates metabolic genes in the hypothalamus, suppressing genes in the glycolysis and pentose phosphate pathways, while increasing expression of genes regulating pyruvate dehydrogenase and long-chain fatty acyl-CoA and cholesterol biosynthesis, thereby rerouting of carbon substrates from glucose metabolism to lipid metabolism required for the biogenesis of membranes for neuronal and glial function and synaptic remodeling. Furthermore, based on the transcriptional signatures, these changes in gene expression involve neurons, astrocytes, oligodendrocytes, microglia and endothelial cells. Thus, peripheral insulin acutely and potently regulates expression of a broad network of genes involved in neurotransmission and brain metabolism. Dysregulation of these pathways could have dramatic effects in normal physiology and diabetes.


2019 ◽  
Vol 12 (3) ◽  
pp. 215-229 ◽  
Author(s):  
Jasmine Kaur ◽  
Abdelkader Daoud ◽  
Scott T. Eblen

Background: Epigenetic alterations comprise key regulatory events that dynamically alter gene expression and their deregulation is commonly linked to the pathogenesis of various diseases, including cancer. Unlike DNA mutations, epigenetic alterations involve modifications to proteins and nucleic acids that regulate chromatin structure without affecting the underlying DNA sequence, altering the accessibility of the transcriptional machinery to the DNA, thus modulating gene expression. In cancer cells, this often involves the silencing of tumor suppressor genes or the increased expression of genes involved in oncogenesis. Advances in laboratory medicine have made it possible to map critical epigenetic events, including histone modifications and DNA methylation, on a genome-wide scale. Like the identification of genetic mutations, mapping of changes to the epigenetic landscape has increased our understanding of cancer progression. However, in contrast to irreversible genetic mutations, epigenetic modifications are flexible and dynamic, thereby making them promising therapeutic targets. Ongoing studies are evaluating the use of epigenetic drugs in chemotherapy sensitization and immune system modulation. With the preclinical success of drugs that modify epigenetics, along with the FDA approval of epigenetic drugs including the DNA methyltransferase 1 (DNMT1) inhibitor 5-azacitidine and the histone deacetylase (HDAC) inhibitor vorinostat, there has been a rise in the number of drugs that target epigenetic modulators over recent years. Conclusion: We provide an overview of epigenetic modulations, particularly those involved in cancer, and discuss the recent advances in drug development that target these chromatin-modifying events, primarily focusing on novel strategies to regulate the epigenome.


2020 ◽  
Author(s):  
Trieu-Duc Vu ◽  
Yuki Iwasaki ◽  
Kenshiro Oshima ◽  
Masato Nikaido ◽  
Ming-Tzu Chiu ◽  
...  

AbstractTerritorial defense involves frequent aggressive confrontations with competitors, but little is known about how brain-transcriptomic profiles change between individuals competing for territory establishment. Our previous study elucidated that brain-transcriptomic synchronization occurs in a pair-specific manner between two males of the fish Betta splendens during fighting, reflecting a mutual assessment process between them at the level of gene expression. Here we evaluated how the brain-transcriptomic profiles of opponents change immediately after shifting their social status (i.e., the winner/loser has emerged) and 30 min after this shift. We showed that unique and carryover hypotheses can be adapted to this system, in which changes in the expression of certain genes are unique to different fighting stages and in which the expression patterns of certain genes are transiently or persistently changed across all fighting stages. Interestingly, the specificity of the brain-transcriptomic synchronization of a pair during fighting was gradually lost after fighting ceased, because of the decrease in the variance in gene expression across all individuals, leading to the emergence of a basal neurogenomic state. Strikingly, this unique state was more basal than the state that existed in the before-fighting group and resulted in the reduced and consistent expression of genes across all individuals. In spite of the consistent and basal overall gene expression in each individual in this state, expression changes for genes related to metabolism, learning and memory, and autism still differentiated losers from winners. The fighting system using male B. splendens thus provides a promising platform for investigating neurogenomic states of aggression in vertebrates.Author summaryCompetitive interactions involve complex decision-making tasks that are shaped by mutual feedback between participants. When two animals interact, transcriptomes across their brains synchronize in a way that reflects how they assess and predict the other’s fighting ability and react to each other’s decisions. Here, we elucidated the gradual loss of brain-transcriptomic synchrony between interacting opponents after their interaction ceased, leading to the emergence of a basal neurogenomic state, in which the variations in gene expression were reduced to a minimum among all individuals. This basal neurogenomic state shares common characteristics with the hibernation state, which animals adopt to minimize their metabolic rates to cope with harsh environmental conditions. We demonstrated that this unique neurogenomic state, which is newly characterized in the present study, is composed of the expression of a unique set of genes, each of which was presumably minimally required for survival, providing a hypothesis that this state represents the smallest unit of neurogenomic activity for sustaining an active life.


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