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Exercise, Metabolism and Oxidative Stress in the Epigenetic Landscape
Published in James N. Cobley, Gareth W. Davison, Oxidative Eustress in Exercise Physiology, 2022
Gareth W. Davison, Colum P. Walsh
Acetyl-CoA is involved in the transfer of an acetyl group to lysine amino acids on the N-terminal tails of histone to yield acetylation (Martinez-Reynes and Chandel, 2020; Vanzan et al., 2017). Acetylation occurs on each of the four histones via HAT enzymes, and HATs can be sensitive to fluxes in intracellular acetyl-CoA concentration (Kaelin and McKnight, 2013; Wong et al., 2017). Histone acetylation regulates gene transcription. For example, acetylation (i.e. H3K9ac, H3K27ac) at specific gene loci is implicated in transcriptional activation by opening chromatin structure, through a combination of (1) histone acetylation neutralising their positive charge which may weaken the interaction of the nucleosome with the DNA, leading to the opening of chromatin and active transcription and (2) histone acetylation acting as a docking station for the recruitment of transcription regulators (Vanzan et al., 2017; Wang et al., 2018; Davison et al., 2021).
Role of Histone Methyltransferase in Breast Cancer
Published in Meenu Gupta, Rachna Jain, Arun Solanki, Fadi Al-Turjman, Cancer Prediction for Industrial IoT 4.0: A Machine Learning Perspective, 2021
Surekha Manhas, Zaved Ahmed Khan
Moreover, there are several other studies that suggest that H3K4me3 enhances downstream H4/H3-dependent acetylation by recruiting HATs. The readers of H3K4me3 have been already identified in various HAT complexes. The complex, SAGA HAT, has a component, SGF29, that has tandem tudor methyl lysine/argnine binding domain that binds with H3K4me3 and shows overlapping with H3K4me3 at gene promoters. Deletion of SGF29 leads to H3K9ac loss along with SAGA complex loss at target points [47]. Correspondingly, yeast NuA3 [48], NuA4 [49], and mammalian HBO1 [50] all provide various other examples associated with HAT complexes, which encompass PHD fingers that bind with H3K4me3 preferentially. The dynamic turnover of lysine acetylation at H3 histone protein residues by the combinatorial HDAC and HAT CBP/p300 actions have been manifested to occur on tails of H3 histone protein residues with already pre-existing H3K4me3, except that no other modifications correlated with the expression of active genes, including H3K36me3 or H3K79me3 [51]. Specifically, H3K4me3-dependent acetylation is highly conserved in higher eukaryotes by including humans, mice, and flies. H3K4me3 loss upon the deletion of CFP1 results in CpGI-related H3K9ac loss in embryonic stem cells [26].
Mitochondrial Stress and Cellular Senescence
Published in Shamim I. Ahmad, Handbook of Mitochondrial Dysfunction, 2019
Irene L. Tan, Michael C. Velarde
Senescence-associated heterochromatin foci (SAHF) are protein-DNA complexes which contain heterochromatin-associated proteins, including heterochromatin protein 1 (HP1) and trimethylated histone 3 at lysine 9 (H3K9me3), while excluding the euchromatin-associated markers acetylated histone 3 at lysine 9 (H3K9ac) and methylated histone 3 at lysine 4 (H3K4me) (Narita et al. 2003). SAHF is also associated with co-recruitment of heterochromatin proteins and the RB tumor suppressor to E2F-responsive promoters for the stable repression of E2F target genes (Aird et al. 2013; Narita et al. 2003). SAHF formation causes extensive chromatin reorganization in the nucleus that may result in silencing of proliferation-promoting genes (Aird and Zhang 2013). These chromatin alterations form punctate DNA foci called SAHF (Corpet and Stucki 2014; Narita et al. 2003).
Epigenetic master regulators HDAC1 and HDAC5 control pathobiont Enterobacteria colonization in ileal mucosa of Crohn’s disease patients
Published in Gut Microbes, 2022
Mélissa Chervy, Adeline Sivignon, Flavie Dambrine, Anthony Buisson, Pierre Sauvanet, Catherine Godfraind, Matthieu Allez, Lionel Le Bourhis, Nicolas Barnich, Jérémy Denizot
As H3 acetylation is mostly regulated by HDAC, we hypothesize that HDAC could be central in the control of AIEC colonization. In order to understand whether HDAC regulate the entry of AIEC bacteria within host cells, Caco-2 IECs were pre-treated with a global HDAC inhibitor (class I and II inhibitor), suberoylanilide hydroxamic acid (SAHA) at different concentrations before infection with the AIEC reference strain LF82. Efficacy and safety of the HDAC inhibitor were confirmed through the observation of a dose-dependent accumulation of H3K9ac mark by western blot and of a cell viability between 78.9% and 95.9%, respectively (Figure S2A, B). At 3 h post-infection, adherent bacteria were numbered and no significant differences between conditions were observed, demonstrating that HDAC are not involved in the AIEC adhesion process to IECs (Figure 2a). In contrast, a gentamicin protection assay revealed a significantly enhanced invasion ability of AIEC bacteria in SAHA-pretreated cells compared to DMSO control (vehicle) condition, with a dose-dependent effect (Figure 2b). Similar results were obtained in another cell line (T84) (Figure S3A-B). Hence, global HDAC inhibition increases the ability of AIEC bacteria to invade IECs, indicating that a physiological HDAC activity is essential to limit the entry of AIEC pathobiont bacteria within IECs.
Effect of titanium dioxide nanoparticles on histone modifications and histone modifying enzymes expression in human cell lines
Published in Nanotoxicology, 2022
Marta Pogribna, Beverly Word, Beverly Lyn-Cook, George Hammons
Acetylated H3K9 (H3K9ac) is considered to be a mark of active chromatin and is found enriched at regions surrounding transcriptional start sites (Karmodiya et al. 2012). In prostate and ovarian tumors, decrease of H3K9ac has been linked with tumor progression (Seligson et al. 2009; Zhen et al. 2010). On the contrary, in hepatocellular carcinoma an increase in H3K9ac levels was reported (Bai et al. 2007). Also, patients with non-small cell lung adenocarcinoma or astrocytoma, and exhibiting reduced H3K9ac expression level had a better prognosis (Barlési et al. 2007). H3K18 acetylation (H3K18ac) is regarded as a general marker for active transcription. Loss of H3K18ac is correlated with poor prognosis in patients with several cancer types (Barber et al. 2012). However, low expression of H3K18ac has been associated with a better prognosis for patients with esophageal squamous cell carcinoma or glioblastoma (Tzao et al. 2009; Liu et al. 2010). The levels of H3K18ac were found to be higher in primary prostate cancers and metastases and increased H3K18ac identified patients at increased risk of prostate cancer recurrence (Damodaran et al. 2017). Higher H3K18ac expression has also been reported in pancreatic cancer (Juliano et al. 2016). Increased levels of H4K8ac expression have been reported in PC3 prostate cancer cells (Xu et al. 2018) and breast cancer (Li et al. 2019). Citrullinated histone H3 (H3cit) contributes to the regulation of chromatin de-condensation (Leshner et al. 2012). Histone citrullination has been shown to be a contributor to autoimmune diseases (Wang and Wang 2013).
Upregulation of OATP1A2 in human oesophageal squamous cell carcinoma cells via the HDAC6-GCN5/PCAF-H3K9Ac axis
Published in Xenobiotica, 2021
Xiaoli Zheng, Jian V. Zhang, Yanfeng Bai, Jiaqi Wang, Mingfeng Jiang, Su Zeng, Lvhua Wang
Histone acetylation sites such as H3K18ac, H3K27ac and H3K9Ac are associated with high gene expression. ChIP-qPCR was used to quantify active histone acetylation sites at the OATP1A2 promoter. We initially observed that OATP1A2 transcription was markedly increased in the three selected pairs of ESCC tissues (Figure 4(A)). By employing ChIP-qPCR analysis, highly enriched H3K9Ac was observed around the transcription start site (TSS) of OATP1A2 in SAHA-treated ESCC cells (Figure 4(B, C)). ChIP assays in the normal oesophagus and paired ESCC tissues further revealed that H3K9Ac was enriched at the OATP1A2 promoter of tumour tissues in vivo (Figure 4(D)). It was suggested that gene-specific enrichment of H3K9Ac occurs at the OATP1A2 promoter when OATP1A2 is upregulated in ESCC.