Search Results (304)

Quaternary ammonium compounds (QACs) are a class of chemicals used for their antimicrobial, surfactant, and antistatic properties. QACs are present in many consumer products, and people are regularly exposed to them. We have previously shown reproductive toxicity in mice exposed to the disinfectants alkyl dimethyl benzyl ammonium chloride (ADBAC) and dodecyl dimethyl ammonium chloride (DDAC). To assess the long-term reproductive impacts, a generational reproductive study was conducted. Sperm parameters were determined by CASA and epigenetic enzyme mRNA expression was determined by pathway-focused RT-PCR. Mice ambiently exposed to ADBAC+DDAC exhibited decreases in reproductive indices that persisted through the F1 generation. Male mice (F0) dosed with 120 mg/kg/day of ADBAC+DDAC exhibited decreased sperm concentration and motility that persisted through the F1 generation. Changes in the mRNA expression of chromatin-modifying enzymes in the testes were seen. Two histone acetyltransferases (Hat1 and Kat2b) were upregulated, and one lysine-specific demethylase (Kdm6b) was downregulated in the F0 generation. The DNA methyltransferase Dnmt1 was downregulated in F1 males. These changes in chromatin-modifying enzymes are known to decrease fertility and could be a mechanism for ADBAC+DDAC reproductive toxicity. In all experiments, the F2 generation was similar to the controls, showing multi-generational but not trans-generational epigenetic inheritance. Full article

Background: Robust evidence supports the role of tetrahydrobiopterin (BH4) metabolism in sustaining inflammation; however, the mechanisms underlying the persistent upregulation of the BH4 pathway remain incompletely understood. This study investigated the epigenetic regulation of BH4 metabolism following a single injection of lipopolysaccharide (LPS) in the mouse hippocampus. Methods: Male C57BL/6J mice received either saline or LPS (0.33 mg/kg, i.p.) and were sacrificed at 4 h or 24 h post injection. Behavioral assessments and analyses of hippocampal neurotransmitter metabolism, DNA methylation profile, oxidative stress, and inflammasome activation were performed. Neopterin levels, a marker of immune system activation, were measured in both the plasma and hippocampus. Results: LPS-treated mice exhibited sickness behavior, including reduced locomotor and exploratory activity at both 4 and 24 h. While exploratory behavior showed partial recovery by 24 h, locomotor activity remained impaired. Neopterin levels increased in both the plasma and hippocampus following LPS administration but returned to baseline in the hippocampus by 24 h. Despite the normalization of neopterin, a persistent pro-inflammatory state in the hippocampus was evident at 24 h, as shown by increased expression of Ikbkb and components of the NLRP3 inflammasome, along with elevated oxidative stress markers. Upregulation of Nrf-2 and Hmox1 suggested activation of a protective antioxidant response. Dopaminergic metabolism was disrupted, indicating impaired BH4-dependent dopamine turnover. Epigenetic analysis revealed increased expression of DNA methyltransferases (Dnmt1, Dnmt3a, Dnmt3b) and Tet2, along with reduced expression of Tet1 and Tet3. Promoter hypomethylation of Gch1 and Ptps was observed, correlating with increased hippocampal expression and potentially elevated BH4 levels. Conclusions: Together, these findings show that a single LPS challenge was sufficient to induce the activation of the BH4 synthesis pathway during the late acute inflammatory phase, both systemically and in the hippocampus, potentially driven by epigenetic modifications such as promoter hypomethylation. This may contribute to the perpetuation of neuroinflammation. Full article

Background/Objectives: Bisphenols (BPs) and especially bisphenol S (BPS), an analog of bisphenol A (BPA), are widely used and induce oxidative stress, resulting in the inhibition of cell proliferation and induction of apoptosis which all are crucial for reproduction, the progression of pregnancy, and fertility. The present study integrates trophoblastic cells as an in vitro model to provide evidence and investigate the molecular interactions regarding placenta-related pregnancy complications after cytotoxic exposure to BPS. Methods: Human endometrial epithelial adenocarcinoma Ishikawa cell lines and trophoblastic cells were cultured. Cells obtained from the cultures were divided into plates and incubated for 24 h with different concentrations of bisphenol S (BPS). Cell viability was measured using the Countess Automated Cell Counter and the viability of Ishikawa cells was assessed after 48 h and for trophoblasts after 24 h. The effect of siRNA on NANOG expression was evaluated using qRT-PCR. Quantification of DNMT and NANOG was performed by qPCR and the G6PD gene was used as an internal control. Results: Real-time PCR results showed that the expression of the DNMT1 gene varies depending on the concentration of BPS in trophoblastic cells. In Ishikawa cell lines, real-time PCR results showed that DNMT1 gene expression was higher due to cell increase, but the measured fold change did not differ significantly. Data analysis indicated a statistically significant difference between CpDNMT1 in trophoblasts with and without BPS, where higher values were observed in the case of BPS presence (p = 0.019). The largest difference was observed between CpDNMT1 trophoblasts without BPS and CpDNMT1 Ishikawa with BPS (p < 0.001). Silencing the NANOG gene resulted in a reduced expression of DNMT1, while the G6PD gene was still detected. Conclusions: The results of this study highlight the cytotoxic effects of BPS and consequently its effect on trophoblast viability. The results of NANOG-DNMT1 gene expression related to BPS exposure reinforces our understanding of EDC-induced placental dysfunction. Full article

Bladder cancer pathogenesis is closely linked to epigenetic alterations, particularly DNA methylation and demethylation processes. Environmental carcinogens and persistent inflammatory stimuli—such as recurrent urinary tract infections—can induce aberrant DNA methylation, altering gene expression profiles and contributing to malignant transformation. This review synthesizes current evidence on the role of DNA methyltransferases (DNMT1, DNMT3a, DNMT3b) and the hypermethylation of key tumour suppressor genes, including A2BP1, NPTX2, SOX11, PENK, NKX6-2, DBC1, MYO3A, and CA10, in bladder cancer. It also evaluates the therapeutic application of DNA-demethylating agents such as 5-azacytidine and highlights the impact of chronic inflammation on epigenetic regulation. Promoter hypermethylation of tumour suppressor genes leads to transcriptional silencing and unchecked cell proliferation. Urine-based DNA methylation assays provide a sensitive and specific method for non-invasive early detection, with single-target approaches offering high diagnostic precision. Animal models are increasingly employed to validate these findings, allowing the study of methylation dynamics and gene–environment interactions in vivo. DNA methylation represents a key epigenetic mechanism in bladder cancer, with significant diagnostic, prognostic, and therapeutic implications. Integration of human and experimental data supports the use of methylation-based biomarkers for early detection and targeted treatment, paving the way for personalized approaches in bladder cancer management. Full article

Global warming and anthropogenic climate change are projected to expand the geographic distribution and population abundance of ectothermic species and exacerbate the biological invasion of exotic species. DNA methylation, as a reversible epigenetic modification, could provide a putative link between the phenotypic plasticity of invasive species and environmental temperature variations. We assessed and interpreted the epigenetic mechanisms of invasive and indigenous species’ differential tolerance to thermal stress through the invasive species Bemisia tabaci Mediterranean (MED) and the indigenous species Bemisia tabaci AsiaII3. We examine their thermal tolerance following exposure to heat and cold stress. We found that MED exhibits higher thermal resistance than AsiaII3 under heat stress. The fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) results proved that the increased thermal tolerance in MED is closely related to DNA methylation changes, other than genetic variation. Furthermore, the quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting analysis of DNA methyltransferases (Dnmts) suggested that increased expression of Dnmt3 regulates the higher thermal tolerance of female MED adults. A mechanism is revealed whereby DNA methylation enhances thermal tolerance in invasive species. Our results show that the Dnmt-mediated regulation mechanism is particularly significant for understanding invasive species’ successful invasion and rapid adaptation under global warming, providing new potential targets for controlling invasive species worldwide. Full article

DNA methylation is a well-studied epigenetic modification that regulates gene expression, maintains genome integrity, and influences cell fate. It is strictly regulated by a group of enzymes known as DNA methyltransferases (DNMTs). Most DNA methylation occurs at cytosines within symmetrical CpG dinucleotide base pairs, often located at gene promoters or other regulatory elements. Thus, methylation of a promoter CpG island leads to stable transcriptional repression of the associated gene. Nonetheless, abnormal gene expression caused by alterations in DNA methylation has been linked to infertility in both males and females, as well as to reproductive potential and improper post-fertilization embryo development. Recent epigenetic advancements have highlighted the significant association between epigenetic modification and reproductive health outcomes, garnering considerable attention. In this review, we explore significant advancements in understanding DNA methylation, emphasizing its establishment, maintenance, and functions in male and female reproductive sex cells. We also shed light on the recent discoveries on the influence of environmental exposures, nutrition, infection, stress, and lifestyle choices on DNA methylation. Finally, we discuss the latest insights and future directions concerning the diverse functions of DNA methylation in reproductive outcomes. Full article

Nucleobase and nucleoside analogs are critical components of antimetabolite chemotherapy treatments used to disrupt DNA replication and induce apoptosis in rapidly proliferating cancer cells. However, the development of resistance to these agents remains a major clinical challenge. This review explores the epigenetic mechanisms that contribute to acquired chemoresistance, focusing on DNA methylation, histone modifications, and non-coding RNAs (ncRNAs). These epigenetic alterations regulate key processes such as DNA repair, drug metabolism, cell transport, and autophagy, enabling cancer cells to survive and resist therapeutic pressure. We highlight how dysregulation of DNA methyltransferases (DNMTs) and histone acetyltransferases (HATs) modulates expression of transporters (e.g., hENT1, ABCB1), DNA repair enzymes (e.g., Polβ, BRCA1/2), and autophagy-related genes (e.g., CSNK2A1, BNIP3). Furthermore, emerging roles for long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) in regulating nucleoside export and DNA damage response pathways underscore their relevance as therapeutic targets. The interplay of these epigenetic modifications drives resistance to agents such as gemcitabine and 5-fluorouracil across multiple tumor types. We also discuss recent progress in therapeutic interventions, including DNMT and HDAC inhibitors, RNA-based therapeutics, and CRISPR-based epigenome editing. Full article

Background: Protein arginine methyltransferase 3 (PRMT3), a type I family PRMT, regulates the activity of downstream substrates by catalyzing the asymmetric dimethylation of arginine residues. While PRMT3 activity has been reported to be deregulated in many cancers, including glioblastoma (GBM), the underlying signalling mechanisms that contribute to disease progression are largely unknown. Methods: We tested the efficacy of a PRMT3 chemical probe, SGC707, in a cohort of GBM patient-derived primary and recurrent brain tumour stem cell (BTSC) lines. RNA-sequencing, CRISPR-cas9 knockout, and inducible overexpression methods were used to investigate the molecular mechanisms regulated by the aberrant activity of PRMT3 in different BTSC lines. Results: We show that expression of the tumour suppressor protein 4.1B, a negative regulator of PRMT3, predicts the response of GBM BTSCs to the PRMT3 chemical probe, SGC707. Furthermore, PRMT3 modulates the stability and subcellular localization of the downstream effector, UHRF1, a member of the DNA methylation complex. These findings suggest that UHRF1 and DNMT1 may suppress the expression of 4.1B through the increased promoter methylation of EPB4.1L3. Intriguingly, the inducible overexpression of EPB4.1L3 in the BT248^EPB4.1L3low BTSC line mimicked the effects of the pharmacologic and genetic inhibition of PRMT3. In contrast, knockout of EPB4.1L3 in BT143^EPB4.1L3high cells reduced the interactions between PRMT3 and 4.1B proteins, resulting in increased sensitivity of knockout cells to SGC707 treatment. Conclusions: These findings show that 4.1B, PRMT3, and UHRF1/DNMT1 function together to promote BTSC growth. Thus, targeting PRMT3 or UHRF1/DNMT1, especially in tumours with low endogenous 4.1B protein, may have high therapeutic relevance. Full article

DNA methylation, also known as 5-methylcytosine, is an epigenetic modification that has crucial functions in multiple important biological processes in fish, such as gonadal development. The cellular DNA methylation level is tightly regulated by DNA methyltransferases (Dnmt). However, detailed investigations of this family in fish are very scarce. In this study, our results confirmed that teleost genomes contain 4 to 16 Dnmt genes, with diversity likely resulting from a combination of whole-genome duplication (WGD), tandem duplication, and gene loss. Differences were observed in tissue distribution, transcription abundance, and protein structure of Dnmt duplicates, supporting their subfunctionalization or neofunctionalization after duplication. Interestingly, we found that fish Dnmt3b duplicates likely have acquired the functions of mammalian Dnmt3l, which may compensate for the absence of fish Dnmt3l. Furthermore, transcriptome analysis and qPCR results indicated that DNA methyltransferase genes (Dnmt1, Dnmt3aa, Dnmt3ab, Dnmt3ba, and Dnmt3bb.1) possibly play important roles in the natural sex change of protandrous hermaphrodite blackhead seabream (Acanthopagrus schlegelii) and inferred that global remodeling of gonadal DNA methylation, regulated by DNA methyltransferase genes, was closely associated with sex change in sequentially hermaphroditic fishes. Overall, our results may help provide a better understanding of the evolution and function of DNA methyltransferases in fish. Full article

Background: Breast cancer (BC) is the second most common cancer among women in the United States. It has been estimated that one in eight women will be diagnosed with breast cancer in her lifetime. Various BC risk factors, such as age, physical inactivity, and smoking, play a substantial role in BC occurrence and development. Early life dietary intervention with plant-based bioactive compounds has been studied for its potential role in BC prevention. Sulforaphane (SFN), an isothiocyanate, is an antioxidant and anti-inflammatory agent extracted from broccoli sprouts (BSp) and other plants. Dietary supplementation of SFN suppresses tumor growth by inducing protective epigenetic changes and inhibiting cancer cell proliferation. Inulin, as a dietary fiber, has been studied for alleviating GI discomfort and weight loss by promoting the growth of beneficial bacteria in the gut. Objective: Early-life combinatorial treatment with both phytochemical SFN and potential prebiotic agent inulin at lower and safer dosages may confer more efficacious and beneficial effects in BC prevention. Methods: Transgenic mice representing estrogen receptor-negative BC were fed 26% (w/w) BSp and 2% (w/v) inulin supplemented in food and water, respectively. Results: The combinatorial treatment inhibited tumor growth, increased tumor onset latency, and synergistically reduced tumor weight. Gut microbial composition was analyzed between groups, where Ruminococcus, Muribaculaceae, and Faecalibaculum significantly increased, while Blautia, Turicibacter, and Clostridium sensu stricto 1 significantly decreased in the combinatorial group compared with the control group. Furthermore, combinatorial treatment induced a protective epigenetic effect by inhibiting histone deacetylases (HDACs) and DNA methyltransferases (DNMTs). Intermediates in the AKT/PI3K/MTOR pathway were significantly suppressed by the combinatorial treatment, including PI3K p85, p-AKT, p-PI3K p55, MTOR, and NF-κB. Cell cycle arrest and programmed cell death were induced by the combinatorial treatment via elevating the expression of cleaved-caspase 3 and 7 and inhibiting the expressions of CDK2 and CDK4, respectively. Orally administering F. rodentium attenuated tumor growth and induced apoptosis in a syngeneic triple-negative breast cancer (TNBC) mouse model. Conclusions: Overall, the findings suggest that early-life dietary combinatorial treatment contributed to BC prevention and may be a potential epigenetic therapy that serves as an adjunct to other traditional neoadjuvant therapies. Full article

Glioblastoma multiforme (GBM) is a deadly disease known for its genetic heterogeneity. LTR12C is an endogenous retrovirus-derived regulator of pro-apoptotic genes and is normally silenced by epigenetic regulation. In this study, we found that the treatment of two glioblastoma cell lines, T98-G and U87-MG, with DNA methyltransferase (DNMT) and histone deacetylase (HDAC) inhibitors activated LTR12C expression. Combined treatment with these epigenetic drugs exerted a synergistic action on the LTR12C activation in both cell lines, while treatment with each drug as a single agent had a far weaker effect. A strong induction of the expression of the TP63 gene was seen in both cell lines, with the pro-apoptotic isoform GTA-p63 accounting for most of this increase. Coherently, downstream targets of p63, such as p21 and PUMA, were also induced by the combined treatment. Furthermore, we observed a significant reduction in the GBM cell growth and viability following the dual DNMT/HDAC inhibition. These findings reveal that the reactivation of LTR12C expression has the potential to modulate survival pathways in glioblastoma and provide information regarding possible epigenetic mechanisms that can be used to treat this deadly disease. Full article

Objectives: This study aimed to evaluate the prognostic significance of DNA methyltransferases (DNMTs) expression, including DNMT1, DNMT3A, and DNMT3B, in assessing the risk of locoregional recurrence after radiotherapy in patients with locally advanced laryngeal squamous cell carcinoma (LSCC), in order to optimize treatment decision making. Methods: A retrospective analysis was performed on pre-treatment biopsy tissues and clinical data from 58 patients with locally advanced LSCC (stages T3–T4, M0) treated with primary curative radiotherapy. DNMT expression was assessed through immunohistochemistry, and Cox regression analysis was applied to examine associations between methylation marker expression, demographic and clinical data, and both locoregional recurrence and disease-specific mortality. Results: Low expression of DNMT3A (p = 0.045) and the presence of locoregional lymph node metastases at diagnosis (N+-status) (p = 0.002) were associated with disease-specific mortality. Clinical N-status was also associated with locoregional recurrent disease after primary radiotherapy (p < 0.001). Expression of DNMT1 and DNMT3B, age, sex, and clinical T-status were not associated with locoregional recurrences or disease-specific mortality. Conclusions: Low expression of DNMT3A and the presence of regional lymph node metastases were independently associated with disease-specific mortality in patients with locally advanced LSCC treated primarily with definitive, curatively intended radiotherapy. Full article

MSTN has been used as a candidate gene in the genetics, breeding, and improvement of animal breeds. However, the possible mechanism by which the MSTN gene regulates muscle development through PSMA6 is not well understood. Previous methylome and transcriptome sequencing analyses of gluteal muscle tissues from MSTN+/−Luxi cattle and wild-type Luxi cattle identified that the PSMA6 gene exhibited a negative correlation between methylation levels and transcriptional activity. To investigate whether MSTN expression regulates PSMA6 gene expression, we examined the effects of MSTN on DNA methyltransferases (DNMT1, DNMT2, DNMT3A, and DNMT3B) and DNA demethylases (TET1, TET2, and TET3). Additionally, chromatin immunoprecipitation (ChIP) assays were performed to detect the binding interaction between PSMA6 and TET2. In this paper, we first established an MSTN knockdown cellular model to preliminarily validate its regulatory effect on PSMA6 expression. Subsequently, the developmental impact of PSMA6 on bovine skeletal muscle satellite cells was further investigated through both knockdown and overexpression of the PSMA6 gene. Furthermore, we examined changes in the expression of key components of the AKT/mTOR signaling pathway to elucidate the mechanisms underlying the PSMA6-mediated regulation of satellite cell development. The results demonstrate that myostatin (MSTN) inhibition significantly decreased proteasome 20S subunit alpha-6 (PSMA6) gene expression, while increasing demethylase expression, particularly ten-eleven translocation-2 (TET2), which exhibited the most pronounced changes. During the cell proliferation stage, the markers Paired Box 7 (PAX7) and Ki-67 exhibited no significant changes, whereas the PSMA6 gene was either overexpressed or disrupted. Conversely, PSMA6 overexpression altered the myogenic differentiation markers, causing the differential regulation of myosin heavy chain (MyHC) and myogenin (MyoG) expression, with MyHC upregulation and concurrent MyoG downregulation. PSMA6 gene overexpression led to the downregulation of AKT1 and Rac1, as well as the activation of the AKT/mTOR pathway, including key factors such as mTOR, p-mTOR, RPS6, p-RPS6, and RhoA. PSMA6 interference resulted in the downregulation of p-mTOR and the upregulation of p-RPS6. Gene expression profiling in our study revealed that the myostatin (MSTN) knockout model significantly reduced the transcriptional levels of the proteasome α6 subunit (PSMA6) (p < 0.05), with the regulatory intensity showing a significant negative correlation with MSTN expression. This molecular evidence substantiates a negative regulatory axis between MSTN and PSMA6. Functional experiments demonstrated that PSMA6 overexpression specifically enhanced myotube formation rates in bovine skeletal muscle satellite cells, whereas siRNA-mediated PSMA6 knockdown exhibited no significant effects on cellular proliferation, indicating the functional specificity of this gene in myogenic differentiation. Mechanistic investigations further revealed that PSMA6 activates the canonical AKT/mTOR signaling transduction cascade through the phosphorylation of AKT and its downstream effector mTOR, thereby mediating the expression of myogenic regulatory factors MyoD and myogenin. Collectively, these findings demonstrate that MSTN deficiency alleviates the transcriptional repression of PSMA6, remodels skeletal muscle differentiation-associated signaling networks, and ultimately drives the directional differentiation of satellite cells toward myofiber specification. Full article

Epigenetic dysregulation has emerged as an important player in the pathobiology of neurodegenerative diseases (NDDs), such as Alzheimer’s, Parkinson’s, and Huntington’s diseases. Aberrant DNA methylation, histone modifications, and dysregulated non-coding RNAs have been shown to contribute to neuronal dysfunction and degeneration. These alterations are often exacerbated by environmental toxins, which induce oxidative stress, inflammation, and genomic instability. Reversing epigenetic aberrations may offer an avenue for restoring brain mechanisms and mitigating neurodegeneration. Herein, we revisit the evidence suggesting the ameliorative effects of epigenetic modulators in toxin-induced models of NDDs. The restoration of normal gene expressions, the improvement of neuronal function, and the reduction in pathological markers by histone deacetylase (HDAC) and DNA methyltransferase (DNMT) inhibitors have been demonstrated in preclinical models of NDDs. Encouragingly, in clinical trials of Alzheimer’s disease (AD), HDAC inhibitors have caused improvements in cognition and memory. Combining these beneficial effects of epigenetic modulators with neuroprotective agents and the clearance of misfolded amyloid proteins may offer synergistic benefits. Reinforced by the emerging methods for more effective and brain-specific delivery, reversibility, and safety considerations, epigenetic modulators are anticipated to minimize systemic toxicity and yield more favorable outcomes in NDDs. In summary, although still in their infancy, epigenetic modulators offer an integrated strategy to address the multifactorial nature of NDDs, altering their therapeutic landscape. Full article

A characteristic of triple-negative breast cancer (TNBC) is the epigenetic regulation of tumor suppressor genes, leading to TNBC heterogeneity and treatment resistance in patients. TNBC exhibits high methylation rates, leading to the silencing of numerous tumor suppressor genes. DNA methyltransferase inhibitors (DNMTis) have shown limited clinical efficacy in TNBC treatment. This study aims to uncover a target that could be used to reverse the epigenetic silencing of tumor suppressor genes in TNBC. The Western blot analysis demonstrated that ROR1 knockdown, an oncofetal gene, reduced DNMT3A and DNMT3B protein expression in the TNBC cell lines MDA-MB-231 and HCC1806, as well as a non-malignant breast cell line, MCF10A. The reduced representation bisulfite sequencing (RRBS) analysis identified differential methylation of CREB3L1 when ROR1 is knocked down in TNBC cell lines. CREB3L1 is a transcription factor that plays tumor-suppressive roles in TNBC and is commonly epigenetically silenced in patients. This study shows that ROR1 requires pSTAT3 activation to upregulate DNMT3A and DNMT3B expression to induce CREB3L1 epigenetic silencing in TNBC. ROR1 knockdown resulted in the re-expression of CREB3L1 in TNBC cells. The data provide evidence that ROR1 inhibition, in combination with DNMTis, could enhance patient outcomes as a therapeutic approach for TNBC. Full article