World Trade Center (WTC) dust exposure in mice is associated with inflammation,oxidative stress and epigenetic changes in the lung

Exposure to World Trade Center (WTC) dust has been linked to respiratory disease in humans. In the present studies we developed a rodent model of WTC dust exposure to analyze lung oxidative stress and inflammation, with the goal of elucidating potential epigenetic mechanisms underlying these responses. Exposure of mice to WTC dust (20 μg, i.t.) was associated with upregulation of heme oxygenase-1 and cyclooxygenase-2 within 3 days, a response which persisted for at least 21 days. Whereas matrix metalloproteinase was upregulated 7 days post-WTC dust exposure, IL-6RA1 was increased at 21 days; conversely, expression of mannose receptor, a scavenger receptor important in particle clearance, decreased. After WTC dust exposure, increases in methylation of histone H3 lysine K4 at 3 days, lysine K27 at 7 days and lysine K36, were observed in the lung, along with hypermethylation of Line-1 element at 21 days. Alterations in pulmonary mechanics were also observed following WTC dust exposure. Thus, 3 days post-exposure, lung resistance and tissue damping were decreased. In contrast at 21 days, lung resistance, central airway resistance, tissue damping and tissue elastance were increased. These data demonstrate that WTC dust-induced inflammation and oxidative stress are associated with epigenetic modifications in the lung and altered pulmonary mechanics. These changes may contribute to the development of WTC dust pathologies.     

Hypoxia mimetic deferoxamine influences the expression of histone acetylation- and DNA methylation-associated genes in osteoblasts

Purpose of the study: Sufficient oxygen supply to bone tissue is essential for normal bone development and efficient bone repair. Hypoxia and hypoxia-inducible factor 1α (HIF1α) signaling pathway have been shown to exhibit profound effects on proliferation, differentiation as well as gene and protein expression in osteoblasts, osteoclasts and mesenchymal stem cells; however, as epigenetic mechanisms also perform an important regulatory role in these cells, our aim was to elucidate whether hypoxia mimetic deferoxamine could influence epigenetic mechanisms in bone cells by modulating the gene expression levels of chromatin-modifying enzymes.

Materials and methods: Osteoblast cell line HOS was exposed to deferoxamine, a widely used hypoxia mimetic, and expression profile of 40 genes associated with histone acetylation, deacetylation and DNA methylation was determined using quantitative real time polymerase chain reaction (qPCR) array followed by individual qPCR analyses. In addition, genes associated with hypoxia response, RANK/RANKL/OPG system, WNT/β-catenin signaling pathway and oxidative stress were also analyzed.

Results: We observed induced expression of histone deacetylase 9 (HDAC9) and suppressed expression of K(lysine) acetyltransferase 5 (KAT5) and DNA methyltransferase 3A (DNMT3A) demonstrating for the first time that expression of genes encoding chromatin-modifying enzymes could be influenced by hypoxia mimetic in HOS cells.

Conclusions: Based on our results we can conclude that hypoxia mimetic deferoxamine influences expression of histone acetylation- and DNA methylation-associated genes in osteoblasts and that further studies of hypoxia-induced epigenetic changes in bone cells should be undertaken.     

MiR-101 reverses the hypomethylation of the LMO3 promoter in glioma cells

LIM-only protein 3 (LMO3), a member of the LIM-only protein group, is a new DNA methylation gene that was identified in gliomas via the MeDIP-Chip in our previous study. In this study, we found that LIM-only protein 3 (LMO3) is hypomethylated and overexpressed in glioma cells and tissues. The overexpression of LMO3 was correlated with a poor prognosis in glioma patients, and LMO3 was indirectly inhibited by the tumor suppressor miR-101, which is a potential prognosis marker of gliomas. MiR-101 decreased the expression of LMO3 by reversing the methylation status of the LMO3 promoter and by inhibiting the presence of the methylation-related histones H3K4me2 and H3K27me3 and increasing the presence of H3K9me3 and H4K20me3 on the promoter. It was determined that miR-101 decreases the occupancy of H3K27me3 by inhibiting EZH2, DNMT3A and EED and decreases the H3K9me3 occupancy on the LMO3 promoter via SUV39H1, SUV39H2, G9a and PHF8. Furthermore, miR-101 suppresses the expression of LMO3 by decreasing USF and MZF1.     

Epigenetic mechanisms in odontogenic tumors: A literature review

ObjectiveEpigenetic mechanisms, such as DNA methylation, regulate important biological processes as gene expression and it was suggested that these phenomena play important roles in the carcinogenesis and tumor biology. The aim of this review is to provide the current state of knowledge about epigenetic alterations, focusing mainly on DNA methylation, reported in odontogenic tumors.DesignLiteratures were searched based in the combination of the following keywords: odontogenic tumors, epigenetics, DNA methylation, histone modifications, non-coding RNA, microRNA, DNA methyltransferases. Electronic databases (Medline/PubMed, Scopus and Web of Science) were screened.ResultsThe analysis of epigenetic alterations in different tumors has rapidly increased; however, limited information is available about epigenetic mechanisms involved in the formation of odontogenic tumors. DNA methylation is the most studied epigenetic modification in these tumors and the participation of non-coding RNA’s in odontogenic tumors has been recently addressed. Differential expression of DNA methyltransferases, altered DNA methylation patterns and aberrant expression of non-coding RNA’s were reported in odontogenic tumors.ConclusionsCurrent studies suggest epigenetics as an emerging mechanism, possibly implicated in etiopathogenesis of odontogenic tumors. Deeper understanding of the epigenetic abnormalities in these tumors could show potential applications as biomarkers or therapeutic possibilities in the future.     

Jumonji domain-containing protein 3 regulates the early inflammatory response epigenetically in human periodontal ligament cells

ObjectiveTo investigate the role of the histone 3 lysine 27 trimethylation (H3K27me3) demethylase Jumonji domain-containing protein 3 (Jmjd3) in the epigenetic regulation of the inflammatory response in human periodontal ligament cells (HPDLs).DesignHPDLs were stimulated with lipopolysaccharide from E. coli. The expression of Jmjd3 in HPDLs was examined by quantitative real-time polymerase chain reaction (Q-PCR), Western Blot and immunofluorescent staining. Potential target genes were selected by silencing Jmjd3 and were confirmed by Chromatin Immunoprecipitation (ChIP).ResultsQ-PCR, Western Blot and immunofluorescent staining revealed that the expression of Jmjd3 was increased in inflamed HPDLs. Knockdown of Jmjd3 led to the suppression of inflammation-induced up-regulation of interleukin-6 and interleukin-12. Moreover, ChIP assays demonstrated that Jmjd3 was recruited to the promoters of interleukin-6 and interleukin-12b and this recruitment was associated with decreased levels of trimethylated histone 3 lysine 27 (H3K27).ConclusionsIt was concluded that Jmjd3 regulated the activation of interleukin-6 and interleukin-12b in the early inflammatory response of HPDLs via demethylation of H3K27me3 at promoters. This molecular event may play an important role in the regulation of the inflammatory response in HPDLs.     

子痫前期胎盘全基因组DNA甲基化水平研究

目的:探讨子痫前期(pre-eclampsia PE)胎盘全基因组DNA甲基化水平。方法:收集子痫前期患者胎盘标本21例,分为足月组(9例)和非足月组(12例),另选择正常孕妇胎盘19例作为对照。检测胎盘全基因组DNA甲基化水平,并收集患者的临床资料进行回顾性研究。结果:子痫前期足月组胎盘与正常胎盘全基因组DNA甲基化水平差异无统计学意义(P>0.05),非足月组较正常胎盘差异有统计学意义(P<0.05);非足月组子痫前期胎盘全基因组DNA甲基化水平仅与收缩压存在相关性,与24 h尿蛋白定量无关。结论:表观遗传修饰异常存在于非足月分娩的子痫前期胎盘中,可能参与了子痫前期发生发展。     

DNA Methylation as a Therapeutic Target in Hematologic Disorders: Recent Results in Older Patients with Myelodysplasia and Acute Myeloid Leukemia

DNA methylation provides a major epigenetic code (besides histone modification) of the lineage- and development-specific genes (such as regulators of differentiation in the hematopoietic lineages) that control expression of normal cells. However, DNA methylation is also involved in malignancies because aberrant methylating gene activity occurs during leukemic transformation. Thus, genes such as tumor suppressor genes, growth-regulatory genes, and adhesion molecules are often silenced in various hematopoietic malignancies by epigenetic inactivation via DNA hypermethylation. This inactivation is frequently seen not only in transformed cell lines but also in primary leukemia cells. Because this defect is amenable to reversion by pharmacologic means, agents that inhibit DNA methylation have been developed to specifically target this hypermethylation defect in leukemia and preleukemia cases. The most clinically advanced agents, the azanucleosides 5-azacytidine and 5-aza-2'-deoxycytidine (decitabine), were discovered more than 25 years ago, when their methylation-inhibitory activities, even at low concentrations, became apparent. Although both of these agents, like cytarabine, had been clinically used until then at high doses, the redevelopment of these agents for low-dose schedules has revealed very interesting clinical activities for treating myelodysplasia (MDS) and acute myeloid leukemia (AML). Because these diseases occur mostly in patients over 60 years of age, low-dose schedules with these compounds provide a very promising approach in such patient groups by virtue of their low nonhematologic toxicity profiles. In the present review, we describe the development of treatments that target DNA hypermethylation in MDS and AML, and clinical results are presented. In addition, pharmacologic DNA demethylation may be viewed as a platform for biological modification of malignant cells to become sensitized (or resensitized) to secondary signals, such as differentiating signals (retinoids, vitamin D3) and hormonal signals (eg, estrogen receptor in breast cancer cells, androgen receptor in prostate cancer cells). Finally, an in vitro synergism between the reactivating potency of demethylating agents and inhibitors of histone deacetylation has been tested in several pilot studies of AML and MDS treatment. Finally, gene reactivation by either group of compounds results in therapeutically meaningful reactivation of fetal hemoglobin in patients with severe hemoglobinopathies, extending the therapeutic range of derepressive epigenetic agents to nonmalignant hematopoietic disorders.     

Clinicopathologic and molecular features of sporadic microsatellite- and chromosomal-stable colorectal cancers

Background and aims Chromosomal instability (CIN) and microsatellite instability (MSI) are two major causes of colorectal cancers. Recently, a percentage of colorectal cancers were found to be neither CIN nor MSI. This study was performed to explore whether microsatellite- and chromosomal-stable (MACS) colorectal cancers comprise a substantially distinct subtype. Materials and methods Sixty-nine sporadic colorectal cancers were classified into three subsets according to ploidy and microsatellite instability status: CIN+, MSI+, and MACS. Clinicopathologic, genetic, and epigenetic differences among these three groups were investigated by immunohistochemical analysis of p53, APC, hMLH1, and BAX and methylation study of p14 ^ARF , hMLH1, p16 ^INK4a , MGMT, and MINT1 with methylation-specific polymerase chain reaction. Results The 69 cases included 49 CIN+, 7 MSI+, and 13 MACS. MACS were found to differ from CIN+ and MSI+ in three aspects. The clinicopathologic features of MACS were similar to MSI+ but distinguished from CIN+. Comparatively, MACS preferred proximal location and poor differentiation (p < 0.05). An immunohistochemical study demonstrated that MACS had a lower rate of loss of hMLH1 or BAX protein than MSI+ and less loss of APC protein than CIN+. In an epigenetic aspect, both MACS and MSI+ had a high rate of CpG island methylator phenotype (46.2 and 42.9%). However, they differed in the presence of hMLH1 methylation (7.7 vs 57.1%, p < 0.05). Otherwise, compared with CIN+, MACS had a more frequent CpG island methylator phenotype and MINT1 methylation (p < 0.05) and relatively more common p16 ^INK4a methylation with marginal significance (p = 0.056). Conclusion MACS sporadic colorectal cancers may compose a unique phenotype with distinct clinicopathologic and molecular characteristics. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this article.