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Naturally Occurring Histone Deacetylase (HDAC) Inhibitors in the Treatment of Cancers
Published in Namrita Lall, Medicinal Plants for Cosmetics, Health and Diseases, 2022
Sujatha Puttalingaiah, Murthy V. Greeshma, Mahadevaswamy G. Kuruburu, Venugopal R. Bovilla, SubbaRao V. Madhunapantula
Since histones play an important role in the compactness of DNA, modifying these proteins through acetylation in turn modulates the expression of genes (Dong and Weng, 2013). Acetylation of histone proteins facilitates and enhances the gene transcription, whereas deacetylation suppresses the transcription by enhancing the compact packing of DNA (Park and Kim, 2020). Acetylation of histones is carried out by histone acetyltransferase (HAT), while deacetylation is performed by histone deacetylase (HDACs) enzymes (Legube and Trouche, 2003).
Epigenetics of exercise
Published in Adam P. Sharples, James P. Morton, Henning Wackerhage, Molecular Exercise Physiology, 2022
Daniel C. Turner, Robert A. Seaborne, Adam P. Sharples
By contrast, acetylation modifications that occur along histone tails are relatively more straightforward to understand. Indeed, the enzymes responsible for histone acetylation are commonly referred to as histone acetyltransferases (HATs; three main protein families, GNAT, MYST and P300/CREB families) and histone deacetylases (HDACs; for which there are sub-categories of class I, class II, class III and class IV HDACs). More comprehendible is that histone acetylation only exists on one level, unlike histone methylation that has three levels as described above. Of particular interest for molecular exercise physiologists is the class III HDACs, as this class of enzymes contains the sirtuins which are commonly implicated in processes such as ageing, stress resistance and low-calorie insults (25). The sirtuins are NAD+/NADH sensors that detect the signal from the alterations in mitochondrial reduction/oxidation (redox state) following the breakdown of nutrients required to fuel exercise, as discussed in general in Chapter 7 and in response to endurance exercise in Chapter 9. As a general rule, when a histone is acetylated, it creates a chromatin state that helps to activate and increase transcription of genes near those loci (site or location of a specific gene). This is due to the new acetyl group changing the electrical charge between histones and DNA, repelling their tightly bound association and creating a more accessible chromatin structure which allows the relevant machinery to perform the processes required for gene transcription (26).
Emerging Highlights on Natural Prodrug Molecules with Multifarious Therapeutic Perspectives
Published in Debarshi Kar Mahapatra, Cristóbal Noé Aguilar, A. K. Haghi, Applied Pharmaceutical Practice and Nutraceuticals, 2021
Mojabir Hussen Ansari, Vaibhav Shende, Debarshi Kar Mahapatra
Romidepsin is a bicyclic depsipeptide that was first isolated from a Gram-negative rod-shaped single polar flagellum bacteria Chromobacterium violaceum.16 In early 1990s, romidepsin remained an important fermentation product for treating tumor (histone deacetylase class-I inhibitor; however, the mechanism is not fully known) forms such as glioblastoma, leukemia, lymphoma, myeloma, and breast, colorectal, gastrointestinal, lung, ovarian, pancreatic, and prostate cancer and also for treating the microbial infections.17 It is a prodrug that requires a reduction of its disulfide bonds to activate its less stable form. Histone acetyltransferases and histone deacetylases control histone acetylation by the way of direct addition of acetyl groups to the lysine residues within the amino-terminal histone tails, which neutralizes the part of the protein and relaxes the chromatin structure.18 Romidepsin is also classified as an epigenetic agent that introduces stable genetic changes by interfering with the gene expression and their function, without any corresponding changes in the DNA sequence.19 In recent years, small molecules of histone deacetylase (HDAC) inhibitors have owned the position of strong anticancer agents, many of which are now FDA approved anticancer agents, which have challenged the position of romidepsin.20
Epigenetic regulation of radioresistance: insights from preclinical and clinical studies
Published in Expert Opinion on Investigational Drugs, 2022
Katherine Shishido, Alexis Reinders, Swapna Asuthkar
Histone modifiers regulate gene transcription through methylation, acetylation, ubiquitination, and phosphorylation [21–23]. Histone modifiers include histone acetyltransferases, histone deacetylases (HDAC), histone methyltransferases, and lysine demethylases [24]. Histone acetyltransferases promote gene expression through the acetylation of lysine residues, which weakens the electrostatic interaction between the negatively charged DNA and histones [25]. In contrast, HDACs suppress gene expression by promoting chromatin compaction via the removal of acetyl groups [26]. Lysine methyltransferases typically silence gene expression by methylating lysine residues [27]. For example, the histone methyltransferase EZH2 catalyzes the tri-methylation of lysine 27 on histone 3 (H3K27me3). On the other hand, histone demethylation is mediated by histone demethylases [26]. In contrast to histone acetylation, histone methylation does not alter the electrostatic charge between DNA and histones but does influence the recruitment and binding of regulatory proteins to chromatin [27–29].
High levels of HDAC expression correlate with microglial aging
Published in Expert Opinion on Therapeutic Targets, 2022
Jaione Auzmendi-Iriarte, Leire Moreno-Cugnon, Ander Saenz-Antoñanzas, Daniela Grassi, Marian M de Pancorbo, Maria-Angeles Arevalo, Ian C Wood, Ander Matheu
Histone modification through acetylation of lysine residues is the primary epigenetic modification that promotes conversion into a more relaxed chromatin state and transcriptional activation [20]. Acetylation is controlled by two antagonistic enzyme families, histone acetyltransferases (HAT) and histone deacetylases (HDAC). HDACs catalyze the removal of acetyl groups from histone tails and provoke a compact chromatin status, whereas HATs have the opposite effect. Thus far, 18 human HDACs have been identified and categorized into four classes depending on their sequence similarity with yeast HDACs. Class I, II, and IV HDACs, also known as classical HDACs, depend on Zn2+ ions located in their catalytic pocket, whereas class III HDACs, known as sirtuins (SIRTs), are nicotinamide adenine dinucleotide (NAD+)-dependent enzymes [21].
Symbiotic microorganisms: prospects for treating atopic dermatitis
Published in Expert Opinion on Biological Therapy, 2022
Rongrong Chai, Zongguang Tai, Yunjie Zhu, Chaochao Chai, Zhongjian Chen, Quangang Zhu
Bioactive metabolites produced by microorganisms using dietary components are the most probable signaling links between the intestinal flora and the host [81]. SCFAs, such as lactate, acetate, propionate, and butyrate, are the products of fermentation by the gut microbiota and are known to promote intestinal epithelial integrity and exert anti-inflammatory effects [82]. SCFAs produced by the intestinal flora may affect the inflammatory state of the skin, as well as the skin flora and homeostasis. The regulation of SCFAs was demonstrated by Schwarz et al. [83]. The effect was histone acetylation-dependent as suppression was abrogated by anacardic acid, a histone acetyltransferase inhibitor [83]. Butyrate is mainly produced by species of the phylum Firmicutes, and propionate by species of the phylum Bacteroidetes [84]. Thus, SCFAs produced by the intestinal flora may affect the inflammatory state of the skin [85]. Figure 1 summarizes the effects of the immunity and metabolism of the intestinal flora on AD.