Dynamic Effect of Di-2-(Ethylhexyl) Phthalate on Testicular Toxicity: Epigenetic Changes and Their Impact on Gene Expression

2010 ◽  
Vol 29 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Shengde Wu ◽  
Jing Zhu ◽  
Yasha Li ◽  
Tao Lin ◽  
Liqiang Gan ◽  
...  

This study investigated epigenetic (specifically, DNA methylation) changes and their impact on gene expression in testes induced by maternal exposure to Di-2-(ethylhexyl) phthalate (DEHP) in mice. Testicular dysgenesis syndrome was induced in fetuses and pups by maternal exposure to DEHP at 500 mg/kg/d, and testes were excised for analysis on gestation day (GD) 19 and postnatal days (PNDs) 3, 21, 56, and 90. High-performance liquid chromatography (HPLC) was performed to analyze DNA methylation status, and expression levels of the DNA methyltransferases were examined by quantitative real-time polymerase chain reaction (qPCR). Testis-specific gene, insulin-like hormone 3 (Insl3), and testosterone production were also detected. DEHP significantly increased DNA methylation levels on GD 19 and PND 3 ( P < .05 and P < .05) but not on PNDs 21, 56, and 90. DEHP also significantly increased the expression of DNA methyltransferases. For DNA methyltransferase 1, the difference was not significant on PND 21, and DNA methyltransferase 3a and 3b returned to normal levels on PND 56. Fetal testes were a main target for DEHP as evidenced by a reduction in Insl3 expression and testosterone production. Effects of DEHP on Insl3 expression continued until PND 21. The DEHP-induced suppression of testosterone had not recovered on PND 56. Changes in DNA methylation may play an important role in abnormal testicular function caused by environmental factors such as maternal exposure to DEHP, which may be a mechanism of DEHP-mediated testicular toxicity.

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Jessilyn Dunn ◽  
Haiwei Qiu ◽  
Soyeon Kim ◽  
Daudi Jjingo ◽  
Ryan Hoffman ◽  
...  

Atherosclerosis preferentially occurs in arterial regions of disturbed blood flow (d-flow), which alters gene expression, endothelial function, and atherosclerosis. Here, we show that d-flow regulates genome-wide DNA methylation patterns in a DNA methyltransferase (DNMT)-dependent manner. We found that d-flow induced expression of DNMT1, but not DNMT3a or DNMT3b, in mouse arterial endothelium in vivo and in cultured endothelial cells by oscillatory shear (OS) compared to unidirectional laminar shear in vitro. The DNMT inhibitor 5-Aza-2’deoxycytidine (5Aza) or DNMT1 siRNA significantly reduced OS-induced endothelial inflammation. Moreover, 5Aza reduced lesion formation in two atherosclerosis models using ApoE-/- mice (western diet for 3 months and the partial carotid ligation model with western diet for 3 weeks). To identify the 5Aza mechanisms, we conducted two genome-wide studies: reduced representation bisulfite sequencing (RRBS) and transcript microarray using endothelial-enriched gDNA and RNA, respectively, obtained from the partially-ligated left common carotid artery (LCA exposed to d-flow) and the right contralateral control (RCA exposed to s-flow) of mice treated with 5Aza or vehicle. D-flow induced DNA hypermethylation in 421 gene promoters, which was significantly prevented by 5Aza in 335 genes. Systems biological analyses using the RRBS and the transcriptome data revealed 11 mechanosensitive genes whose promoters were hypermethylated by d-flow but rescued by 5Aza treatment. Of those, five genes contain hypermethylated cAMP-response-elements in their promoters, including the transcription factors HoxA5 and Klf3. Their methylation status could serve as a mechanosensitive master switch in endothelial gene expression. Our results demonstrate that d-flow controls epigenomic DNA methylation patterns in a DNMT-dependent manner, which in turn alters endothelial gene expression and induces atherosclerosis.


1998 ◽  
Vol 18 (9) ◽  
pp. 5166-5177 ◽  
Author(s):  
Judy A. Mikovits ◽  
Howard A. Young ◽  
Paula Vertino ◽  
Jean-Pierre J. Issa ◽  
Paula M. Pitha ◽  
...  

ABSTRACT The immune response to pathogens is regulated by a delicate balance of cytokines. The dysregulation of cytokine gene expression, including interleukin-12, tumor necrosis factor alpha, and gamma interferon (IFN-γ), following human retrovirus infection is well documented. One process by which such gene expression may be modulated is altered DNA methylation. In subsets of T-helper cells, the expression of IFN-γ, a cytokine important to the immune response to viral infection, is regulated in part by DNA methylation such that mRNA expression inversely correlates with the methylation status of the promoter. Of the many possible genes whose methylation status could be affected by viral infection, we examined the IFN-γ gene as a candidate. We show here that acute infection of cells with human immunodeficiency virus type 1 (HIV-1) results in (i) increased DNA methyltransferase expression and activity, (ii) an overall increase in methylation of DNA in infected cells, and (iii) the de novo methylation of a CpG dinucleotide in the IFN-γ gene promoter, resulting in the subsequent downregulation of expression of this cytokine. The introduction of an antisense methyltransferase construct into lymphoid cells resulted in markedly decreased methyltransferase expression, hypomethylation throughout the IFN-γ gene, and increased IFN-γ production, demonstrating a direct link between methyltransferase and IFN-γ gene expression. The ability of increased DNA methyltransferase activity to downregulate the expression of genes like the IFN-γ gene may be one of the mechanisms for dysfunction of T cells in HIV-1-infected individuals.


2021 ◽  
Vol 9 ◽  
Author(s):  
Marco Gerdol ◽  
Claudia La Vecchia ◽  
Maria Strazzullo ◽  
Pasquale De Luca ◽  
Stefania Gorbi ◽  
...  

DNA methylation is an essential epigenetic mechanism influencing gene expression in all organisms. In metazoans, the pattern of DNA methylation changes during embryogenesis and adult life. Consequently, differentiated cells develop a stable and unique DNA methylation pattern that finely regulates mRNA transcription during development and determines tissue-specific gene expression. Currently, DNA methylation remains poorly investigated in mollusks and completely unexplored in Mytilus galloprovincialis. To shed light on this process in this ecologically and economically important bivalve, we screened its genome, detecting sequences homologous to DNA methyltransferases (DNMTs), methyl-CpG-binding domain (MBD) proteins and Ten-eleven translocation methylcytosine dioxygenase (TET) previously described in other organisms. We characterized the gene architecture and protein domains of the mussel sequences and studied their phylogenetic relationships with the ortholog sequences from other bivalve species. We then comparatively investigated their expression levels across different adult tissues in mussel and other bivalves, using previously published transcriptome datasets. This study provides the first insights on DNA methylation regulators in M. galloprovincialis, which may provide fundamental information to better understand the complex role played by this mechanism in regulating genome activity in bivalves.


2021 ◽  
Vol 22 (23) ◽  
pp. 12989
Author(s):  
Witold Józef Światowy ◽  
Hanna Drzewiecka ◽  
Michalina Kliber ◽  
Maria Sąsiadek ◽  
Paweł Karpiński ◽  
...  

Physical activity is a strong stimulus influencing the overall physiology of the human body. Exercises lead to biochemical changes in various tissues and exert an impact on gene expression. Exercise-induced changes in gene expression may be mediated by epigenetic modifications, which rearrange the chromatin structure and therefore modulate its accessibility for transcription factors. One of such epigenetic mark is DNA methylation that involves an attachment of a methyl group to the fifth carbon of cytosine residue present in CG dinucleotides (CpG). DNA methylation is catalyzed by a family of DNA methyltransferases. This reversible DNA modification results in the recruitment of proteins containing methyl binding domain and further transcriptional co-repressors leading to the silencing of gene expression. The accumulation of CpG dinucleotides, referred as CpG islands, occurs at the promoter regions in a great majority of human genes. Therefore, changes in DNA methylation profile affect the transcription of multiple genes. A growing body of evidence indicates that exercise training modulates DNA methylation in muscles and adipose tissue. Some of these epigenetic markers were associated with a reduced risk of chronic diseases. This review summarizes the current knowledge about the influence of physical activity on the DNA methylation status in humans.


Endocrinology ◽  
2001 ◽  
Vol 142 (8) ◽  
pp. 3389-3396 ◽  
Author(s):  
Jae-Hyeon Cho ◽  
Hiromichi Kimura ◽  
Tatsuya Minami ◽  
Jun Ohgane ◽  
Naka Hattori ◽  
...  

Abstract Expression of rat placental lactogen I is specific to the placenta and never expressed in other tissues. To obtain insight into the mechanism of tissue-specific gene expression, we investigated the methylation status in 3.4 kb of the 5′-flanking region of the rat placental lactogen I gene. We found that the distal promoter region of the rat placental lactogen I gene had more potent promoter activity than that of the proximal area alone, which contains several possible cis-elements. Although there are only 17 CpGs in the promoter region, in vitro methylation of the reporter constructs caused severe suppression of reporter activity, and CpG sites in the placenta were more hypomethylated than other tissues. Coexpression of methyl-CpG-binding protein with reporter constructs elicited further suppression of the reporter activity, whereas treatment with trichostatin A, an inhibitor of histone deacetylase, reversed the suppression caused by methylation. Furthermore, treatment of rat placental lactogen I nonexpressing BRL cells with 5-aza-2′-deoxycytidine, an inhibitor of DNA methylation, or trichostatin A resulted in the de novo expression of rat placental lactogen I. These results provide evidence that change in DNA methylation is the fundamental mechanism regulating the tissue-specific expression of the rat placental lactogen I gene.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Harry MacKay ◽  
C. Anthony Scott ◽  
Jack D. Duryea ◽  
Maria S. Baker ◽  
Eleonora Laritsky ◽  
...  

AbstractDNA methylation regulates cell type-specific gene expression. Here, in a transgenic mouse model, we show that deletion of the gene encoding DNA methyltransferase Dnmt3a in hypothalamic AgRP neurons causes a sedentary phenotype characterized by reduced voluntary exercise and increased adiposity. Whole-genome bisulfite sequencing (WGBS) and transcriptional profiling in neuronal nuclei from the arcuate nucleus of the hypothalamus (ARH) reveal differentially methylated genomic regions and reduced expression of AgRP neuron-associated genes in knockout mice. We use read-level analysis of WGBS data to infer putative ARH neural cell types affected by the knockout, and to localize promoter hypomethylation and increased expression of the growth factor Bmp7 to AgRP neurons, suggesting a role for aberrant TGF-β signaling in the development of this phenotype. Together, these data demonstrate that DNA methylation in AgRP neurons is required for their normal epigenetic development and neuron-specific gene expression profiles, and regulates voluntary exercise behavior.


2011 ◽  
Vol 23 (1) ◽  
pp. 184
Author(s):  
M. Diederich ◽  
J. Heinzmann ◽  
W. Kues ◽  
U. Baulain ◽  
T. Haaf ◽  
...  

The use of oocytes obtained from prepuberal cattle shortens the generation interval by producing descendants of genetically valuable animals before achieving actual cultivation maturity. However, several studies proved that oocytes derived from prepuberal animals differ significantly from oocytes of adult animals with regard to their developmental capability and therefore reproductive potential. Epigenetic events are taken into consideration as a possible reason for this phenomenon. Particularly DNA methylation, allele specific gene expression in a parent-of-origin-specific manner (imprinting), and certain histone modifications, like acetylations, carboxylations, and phosphorylations, play an important role. This project aims to gain knowledge about the mechanisms involved in attaining of the full developmental potential of bovine oocytes. Using immature and in vitro matured oocytes of prepuberal and adult cattle, a comparative study was conducted by measuring mRNA expression of 4 developmentally relevant, but non-imprinted genes (GDF9, GLUT1, PRDX1, and ZAR1) as well as the general DNA methylation status, performed by bisulfite sequencing of 2 satellite sequences [bovine testis satellite I DNA segment 2 (BTSS2) and Bos taurus α satellite I DNA (BTS)]. After various pretreatments, immature bovine oocytes were collected from prepuberal calves [6–9 months, either left untreated (Ca1) or treated with FSH (Ca2) or FSH+IGF1 (Ca3) or FSH+IGFK (Ca4)] and adult animals [≥2nd lactation, either left untreated (Ad1) or treated with FSH (Ad2)] using the Ovum-pick-up (OPU) technique. The Ad1 group was considered the control group. First results of the qPCR analyses of immature oocytes show differences between treatment groups for GLUT1, PRDX1, and ZAR1 transcripts. Compared with Ad1, GLUT1 expression increased in Ad2 [fold change (FC) 2.2], Ca1 (FC 2.0), Ca2 (FC 1.8), and Ca3 (FC 1.4). The genes PRDX1 and ZAR1 were reduced in all groups by 0.02 to 0.07 in comparison with Ad1. The GDF9 showed generally a very low expression. The methylation analysis shows for BTSS2 and BTS significant differences before and after in vitro maturation in the groups Ad1 (BTSS2: 49.6 v. 64.9%), Ad2 (BTS: 76.7 v. 52.5%), Ca1 (BTSS2: 74.6 v. 53.3%), Ca2 (BTS: 72.8 v. 57.8%) and Ca3 (BTSS2: 60.6 v. 71.7%). Currently, the first experiment and statistical analysis are under way. The preliminary data confirm differences in gene expression between prepuberal and adult animals, and demonstrates the dependence of the methylation pattern on age and maturation status. These results contribute to a better understanding of the developmental potential of prepuberal oocytes in order to optimize their use for in vitro production of embryos. This work was supported by the H. Wilhelm Schaumann Foundation, Hamburg.


2019 ◽  
Author(s):  
Oswaldo A. Lozoya ◽  
Fuhua Xu ◽  
Dagoberto Grenet ◽  
Tianyuan Wang ◽  
Sara A. Grimm ◽  
...  

AbstractMitochondrial-driven alterations of the epigenome have been reported but whether they are relevant at the organismal level remain unknown. The viable yellow agouti mouse (Avy) is a powerful epigenetic biosensor model that reports on the DNA methylation status of the Avy locus through the coat color of the animals. Here we show that maternal exposure to rotenone, a potent mitochondrial complex I inhibitor, changes the DNA methylation status of the Avy locus and broadly affects the liver DNA methylome of the offspring. These effects were accompanied by altered gene expression programs that persisted throughout life. Mitochondrial dysfunction was present in the mothers but not in the offspring until 12 months of age, when electron transport and antioxidant defenses were impaired. These results highlight a putative novel role for mitochondria in nuclear epigenetic remodeling during development, raising fundamental questions about the long-term impact of mitochondrial dysfunction to health and disease.


2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Julia C. Chen ◽  
Mardonn Chua ◽  
Raymond B. Bellon ◽  
Christopher R. Jacobs

Osteogenic lineage commitment is often evaluated by analyzing gene expression. However, many genes are transiently expressed during differentiation. The availability of genes for expression is influenced by epigenetic state, which affects the heterochromatin structure. DNA methylation, a form of epigenetic regulation, is stable and heritable. Therefore, analyzing methylation status may be less temporally dependent and more informative for evaluating lineage commitment. Here we analyzed the effect of mechanical stimulation on osteogenic differentiation by applying fluid shear stress for 24 hr to osteocytes and then applying the osteocyte-conditioned medium (CM) to progenitor cells. We analyzed gene expression and changes in DNA methylation after 24 hr of exposure to the CM using quantitative real-time polymerase chain reaction and bisulfite sequencing. With fluid shear stress stimulation, methylation decreased for both adipogenic and osteogenic markers, which typically increases availability of genes for expression. After only 24 hr of exposure to CM, we also observed increases in expression of later osteogenic markers that are typically observed to increase after seven days or more with biochemical induction. However, we observed a decrease or no change in early osteogenic markers and decreases in adipogenic gene expression. Treatment of a demethylating agent produced an increase in all genes. The results indicate that fluid shear stress stimulation rapidly promotes the availability of genes for expression, but also specifically increases gene expression of later osteogenic markers.


2020 ◽  
Author(s):  
Jing Wei ◽  
Jia Cheng ◽  
Nicholas J Waddell ◽  
Zi-Jun Wang ◽  
Xiaodong Pang ◽  
...  

Abstract Emerging evidence suggests that epigenetic mechanisms regulate aberrant gene transcription in stress-associated mental disorders. However, it remains to be elucidated about the role of DNA methylation and its catalyzing enzymes, DNA methyltransferases (DNMTs), in this process. Here, we found that male rats exposed to chronic (2-week) unpredictable stress exhibited a substantial reduction of Dnmt3a after stress cessation in the prefrontal cortex (PFC), a key target region of stress. Treatment of unstressed control rats with DNMT inhibitors recapitulated the effect of chronic unpredictable stress on decreased AMPAR expression and function in PFC. In contrast, overexpression of Dnmt3a in PFC of stressed animals prevented the loss of glutamatergic responses. Moreover, the stress-induced behavioral abnormalities, including the impaired recognition memory, heightened aggression, and hyperlocomotion, were partially attenuated by Dnmt3a expression in PFC of stressed animals. Finally, we found that there were genome-wide DNA methylation changes and transcriptome alterations in PFC of stressed rats, both of which were enriched at several neural pathways, including glutamatergic synapse and microtubule-associated protein kinase signaling. These results have therefore recognized the potential role of DNA epigenetic modification in stress-induced disturbance of synaptic functions and cognitive and emotional processes.


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