ARTICLE | doi:10.20944/preprints201808.0146.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: histone deacetylase inhibitor, MHY2256, p53, apoptosis, autophagy, Ishikawa, endometrial cancer
Online: 7 August 2018 (14:37:46 CEST)
We previously found a novel a new sirtuin (SIRT) inhibitor MHY2256 that exerts anticancer activity through p53 acetylation in MCF-7 human breast cancer cells. Here, we investigated the anticancer activity of MHY2256 against hormone-related cancer, which is an endometrial cancer with poor prognosis. We found that MHY2256 markedly reduced cellular proliferation at low concentrations against Ishikawa endometrial cancer cells. The IC50 values of MHY2256 were much lower than that of salermide. Furthermore, MHY2256 significantly reduced the protein expression and activities of SIRT1, 2, and 3 with similar effects as salermide, a well-known SIRT inhibitor. Particularly, MHY2256 markedly inhibited tumor growth in a tumor xenograft mouse model of Ishikawa cancer cells. During the experimental period, there was no significant change in the body weight of mice treated with MHY2256. Detailed analysis of the sensitization mechanisms of Ishikawa cells revealed that late apoptosis was largely increased by MHY2256. Additionally, MHY2256 increased G1 arrest and reduced cell cyclic-related proteins, suggesting that apoptosis by MHY2256 was achieved by cellular arrest. Particularly, p21 was greatly increased by MHY225656, suggesting that cell cycle arrest by p21 is a major factor in MHY2256 sensitization in Ishikawa cells. We also detected a significant increase in acetylated p53, a target protein of SIRT1, in Ishikawa cells after MHY2256 treatment. In a mouse xenograft model, MHY2256 significantly reduced tumor growth and weight without apparent side effects. These results suggest that MHY2256 exerts its anticancer activity through p53 acetylation in endometrial cancer and can be used for targeting hormone-related cancers.
REVIEW | doi:10.20944/preprints202208.0265.v1
Subject: Life Sciences, Biochemistry Keywords: Post-translational modifications; Epigenetics; Histone Phosphorylation; Histone Ubiquitination; Histone methylation; inflammation; proinflammatory cytokines; DNA methylation; COPD
Online: 15 August 2022 (15:10:21 CEST)
Numerous genes expression lead to inflammation in the individuals’ lungs that have chronic obstructive pulmonary disease (COPD) may be affected by epigenetic alteration. Important epigenetic processes include methylation of DNA and different histones post-translational changes, including ubiquitination, phosphorylation, methylation, SUMOylation and acetylation. Smoking can trigger the enzymes that control these epigenetic changes. According to the majority of publications, both environmental and genetic variables have a substantial role in the development of COPD. Although, the information about COPD epigenetic is not much but, a better perception of the disease pathophysiology and identifying new markers to create novel therapeutics for patients can be achieved via a better understanding of the epigenetic processes involved.
Subject: Biology, Agricultural Sciences & Agronomy Keywords: Ciliophora; mtSSUrRNA; Histone; origin of replication
Online: 19 July 2021 (13:47:38 CEST)
Two distinct isolates of the facultative parasite, Tetrahymena rostrata were compared, identifying and utilising markers that are useful for studying clonal variation within the species. The mitochondrial genomes and several nuclear genes were determined using Illumina short read sequencing. The two T. rostrata isolates had similar morphology and were pathogenic for Deroceras reticulatum slugs. The linear mitogenomes had the gene content and organisation typical of the Tetrahymena genus, comprising 8 tRNA genes, 6 ribosomal RNA genes and 45 protein coding sequences (CDS), twenty-two of which had known function. The two isolates had nucleotide identity within common nuclear markers encoded within the histone H3 and H4 and small subunit ribosomal RNA genes and differed by only 2-4 nucleotides in a region of the characterised actin genes. Variation was observed in several mitochondrial genes and was used to determine intraspecies variation and may reflect the natural history of T. rostrata from different hosts or the geographic origins of the isolates.
REVIEW | doi:10.20944/preprints202104.0742.v1
Subject: Keywords: Diabetes mellitus; Glucose metabolism; Histone deacetylase; HDACs; Histone deacetylase inhibitor; HDACi, Insulin release; Sirtuins, Sirtuin activation
Online: 28 April 2021 (10:23:12 CEST)
Diabetes mellitus (DM) is one of the principal manifestations of metabolic syndrome and its prevalence with modern lifestyle is increasing incessantly. Chronic hyperglycemia can induce several vascular complications that were referred to be the major cause of morbidity and mortality in DM. Although several therapeutic targets have been identified and accessed clinically, the imminent risk of DM and its prevalence are still ascending. Substantial pieces of evidence revealed that histone deacetylase (HDAC) isoforms can regulate various molecular activities in DM via epigenetic and post-translational regulation of several transcription factors. To date, 18 HDAC isoforms have been identified in mammals that were categorized into 4 different classes. Classes I, II, and IV are regarded as classical HDACs, which operate through a Zn-based mechanism. In contrast, class III HDACs or Sirtuins depend on nicotinamide adenine dinucleotide (NAD+) for their molecular activity. Functionally, most of the HDAC isoforms can regulate β cell fate, insulin release, insulin expression and signaling, and glucose metabolism. Moreover, the roles of HDAC members have been implicated in the regulation of oxidative stress, inflammation, apoptosis, fibrosis, and other pathological events, which substantially contribute to diabetes-related vascular dysfunctions. Therefore, HDACs could serve as the potential therapeutic target in DM towards developing novel intervention strategies. This review sheds light on the emerging role of HDACs/isoforms in diabetic pathophysiology and emphasized the scope of their targeting in DM for constituting the novel interventional strategies for metabolic disorders/complications.
ARTICLE | doi:10.20944/preprints202207.0127.v1
Subject: Life Sciences, Molecular Biology Keywords: Epigenetic regulation; Histone demthylases; JMJC; IDR; biomolecular condensates
Online: 7 July 2022 (12:59:29 CEST)
JmjC-family of lysine demethylases (JMJC-KDMs) plays an essential role controlling gene expression and chromatin structure. In most cases, their function has been attributed to the demethylase activity. However, accumulating evidence demonstrates that these proteins play roles distinct from histone demethylation. This raises the possibility that they might share domains that contribute to their functional outcome. Here, we show that the JMJC-KDMs contain low complexity domains as well as intrinsically disordered regions, which in some cases reached 70% of the protein. Our data revealed that PHF2, KDM2A and KDM4B cluster by phase-separation in vitro and in vivo. Moreover, our molecular analysis demonstrated that these domains are important to regulate transcription, suggesting that clustering via phase -separation is a common feature that JMJC-KDMs utilize, in addition to their catalytic activity, to facilitate their functional responses. Our study uncovers a novel potential function for the JMJC-KDM family that sheds light on the mechanisms to achieve the competent concentration of molecules in time and space within the cell nucleus.
REVIEW | doi:10.20944/preprints202205.0158.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: Parkinson’s disease; Epigenetic targets; Histone deacetylases; Inhibitors; PROTACs
Online: 12 May 2022 (05:41:21 CEST)
Parkinson’s disease (PD) is a chronic progressive neurodegenerative disease that increasingly become a global threat for the elder people's health and life. Although there are some drugs in clinic for treating PD, these treatments only can alleviate the symptoms of PD patients but fail in curative therapies. Therefore, seeking other potential mechanisms to develop more effective treatments that can modify the course of PD is still highly desirable. In the last two decades, histone deacetylases as an important group of epigenetic targets in drug discovery have attracted much attention. This review is focused on the current knowledge about histone deacetylases involved in PD pathophysiology and their inhibitors used in PD study. Further perspectives related to small molecules that can inhibit or degrade histone deacetylases to treat PD are also discussed.
REVIEW | doi:10.20944/preprints202104.0068.v1
Subject: Life Sciences, Biochemistry Keywords: DNA methylation; histone modification; epigenetic diet; microRNAs; prediabetes
Online: 2 April 2021 (14:08:11 CEST)
Epigenetics refers to the DNA chemistry changes that result in the modification of gene transcription and translation independently of the underlying DNA coding sequence. Epigenetic modifications are reported to involve various molecular mechanisms, including classical epigenetic changes affecting DNA methylation and histone modifications and small RNA-mediated processes, particularly that of microRNAs. Epigenetic changes are reversible and are closely interconnected. They are recognised to play a critical role as mediators of gene regulation, and any alteration in these mechanisms has been identified to mediate various pathophysiological conditions. Moreover, genetic predisposition and environmental factors, including dietary alterations, lifestyle or metabolic status, are identified to interact with the human epigenome, highlighting the importance of epigenetic factors as underlying processes in the etiology of various diseases such as MetS. This review will reflect on how both the classical and microRNA regulated epigenetic changes are associated with the pathophysiology of Metabolic syndrome. We would then focus on the various aspects of epigenetic-based strategies used to modify MetS outcomes, including epigenetic diet, epigenetic drugs, epigenome editing tools, and miRNA-based therapies.
ARTICLE | doi:10.20944/preprints201809.0486.v1
Subject: Biology, Plant Sciences Keywords: Histone deacetylase, metabolism, peanut, hairy roots, RNA-seq
Online: 25 September 2018 (12:40:05 CEST)
Peanut (Arachis hypogaea) is a crop plant with high economic value, but the epigenetic regulation of its growth and development has only rarely been studied. The peanut histone deacetylase 1 gene (AhHDA1) has been isolated and is known to be ABA- and drought-responsive. In this paper, we investigate the role of AhHDA1 in more detail, focussing on the effect of altered AhHDA1 expression in hairy roots at both the phenotypic and transcriptional levels. Agrobacterium rhizogenes-mediated transformation of A. hypogaea hairy roots was used to analyse how overexpression or RNA interference of AhHDA1 affects this tissue. In both types of transgenic hairy root, RNA sequencing was adopted to identify genes that were differentially expressed, and these genes were assigned to specific metabolic pathways. AhHDA1-overexpressing hairy roots were growth-retarded after 20 d in vitro cultivation, and superoxide anions and hydrogen peroxide accumulated to a greater extent than in control or RNAi groups. Overexpression of AhHDA1 is likely to accelerate flux through various secondary synthetic metabolic pathways in hairy roots, as well as reduce photosynthesis and oxidative phosphorylation. Genes encoding the critical enzymes caffeoyl-CoA O-methyltransferase (Araip.XGB85) and caffeic acid 3-O-methyltransferase (Araip.Z3XZX) in the phenylpropanoid biosynthesis pathway, chalcone synthase (Araip.B8TJ0) and polyketide reductase (Araip.MKZ27) in the flavonoid biosynthesis pathway, and hydroxyisoflavanone synthase (Araip.0P3RJ) and isoflavone 2'-hydroxylase (Araip.S5EJ7) in the isoflavonoid biosynthesis pathway were significantly upregulated by AhHDA1 overexpression, while their expression in AhHDA1-RNAi and control hairy roots remained at a lower level or was unchanged. Our results suggest that alteration of secondary metabolism activities is related to overexpression of AhHDA1, which is mainly reflected in phenylpropanoid, flavonoid and flavonoid biosynthesis. Future studies will focus on the function of AhHDA1 interacting proteins and their action on cell growth and stress responses.
REVIEW | doi:10.20944/preprints201610.0100.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: BET; bromodomain; histone acetylation; gene transcription; BET inhibitor
Online: 24 October 2016 (05:06:56 CEST)
The BET family of proteins is characterized by the presence of two tandem bromodomains and an extra-terminal domain. The mammalian BET family of proteins comprises Brd2, Brd3, Brd4, and Brdt, which are encoded by paralogous genes that may have been generated by repeated duplication of an ancestral gene during evolution. Bromodomains that can specifically bind acetylated lysine residues in histones serve as chromatin-targeting modules that decipher the histone acetylation code. BET proteins play a crucial role in regulating gene transcription through epigenetic interactions between bromodomains and acetylated histones during cellular proliferation and differentiation processes. On the other hand, BET proteins have been reported to mediate latent viral infection in host cells and be involved in oncogenesis. Human BRD4 is involved in multiple processes of the DNA virus life cycle, including viral replication, genome maintenance, and gene transcription through interaction with viral proteins. Aberrant BRD4 expression contributes to carcinogenesis by mediating hyperacetylation of the chromatin containing the cell proliferation-promoting genes. BET bromodomain blockade using small-molecule inhibitors gives rise to selective repression of the transcriptional network driven by c-Myc. These inhibitors are expected to be potential therapeutic drugs for a wide range of cancers. This review presents an overview of the basic roles of BET proteins and highlights the pathological functions of BET and the recent developments in cancer therapy targeting BET proteins in animal models.
ARTICLE | doi:10.20944/preprints202212.0504.v1
Subject: Biology, Animal Sciences & Zoology Keywords: lamprey; cyclostome; meiosis; chromosome; chromatin; histone; RNA polymerase II
Online: 27 December 2022 (02:41:52 CET)
This paper presents results of the experiments performed on a nonconventional and extremely interesting in regard to evolution, creature, the European river lamprey Lampetra fluviatilis (Petromyzontiformes, Cyclostomata), one of the oldest taxa of vertebrates. We present detailed immunocytochemical and electron microscopy analyses of chromosome synapsis, the transcription process, and chromatin dynamics in lamprey prophase I, which is the first time for science. We found that not all chromosomes complete synapsis. Rounded structures were detected in chromatin and in some synaptonemal complexes but their nature could not be determined conclusively. An analysis of RNA polymerase II distribution led to the conclusion that transcriptional reactivation in lamprey prophase I is not associated with the completion of chromosome synapsis. Monomethylated histone H3K4 is localized to meiotic chromatin throughout prophase I, and this pattern has not been previously detected in the animals. Thus, the findings made it possible to identify synaptic and epigenetic patterns specific for this group, and to add new pieces of the puzzle to the discussions of the scientific issues under study. The research on lamprey meiotic chromatin and chromosomal dynamics raises many questions leading to new discoveries.
ARTICLE | doi:10.20944/preprints202105.0251.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Vorinostat, histone deacetylase, HDAC inhibitors, dibenzodiazocines, hydroxamic acid, selectivity
Online: 11 May 2021 (15:35:00 CEST)
Histone deacetylase (HDAC) inhibitors are class of drugs used in the cancer treatment. Here, we developed a library of 19 analogues of Vorinostat, an HDAC inhibitor used in lymphomas treatment. In Vorinostat, we replaced the hydrophobic phenyl group with various tricyclic ‘caps’ possessing a central, eight-membered, heterocyclic ring, and investigated the HDAC activity and cytotoxic effect on the cancer and normal cell lines. We found that three out of the 19 compounds, based on dibenzo[b,f]azocin-6(5H)-one, 11,12-dihydrodibenzo[b,f]azocin-6(5H)-one and benzo[b]naphtho[2,3-f][1,5]diazocine-6,14(5H,13H)-dione scaffolds, showed better HDACs inhibition than the referenced Vorinostat. In leukemic cell line MV4-11 and in lymphoma cell line – Daudi three compounds showed lower IC50 values than Vorinostat. These compounds had higher activity and selectivity against MV4-11 and Daudi cell lines than reference Vorinostat. We also observed a strong correlation between HDACs inhibition and the cytotoxic effect. Cell lines derived from solid tumors: A549 (lung carcinoma) and MCF-7 (breast adenocarcinoma) as well as reference Balb/3T3 (normal murine fibroblasts) were less susceptible to compounds tested. Developed derivatives show superior properties than Vorinostat, thus they are applicable as selective agents for leukemia and lymphoma treatment.
ARTICLE | doi:10.20944/preprints202103.0098.v1
Subject: Biology, Anatomy & Morphology Keywords: substituted esters metabolism; wine fermentation; MGL2; YJU3; histone acetylation
Online: 2 March 2021 (15:05:19 CET)
Esters constitute a wide family of volatile compounds impacting the organoleptic properties of many beverages including wine and beer. They can be classified according to their chemical structure. Higher Alcohols Acetate differ from Fatty Acids Ethyl Esters whereas a third group, Substituted Ethyl Esters, contributes to the fruitiness of red wines. Derived from yeast metabolism, the biosynthesis of Higher Alcohols Acetates and Fatty Acids Ethyl Esters has been widely in-vestigated at the enzymatic and genetic level. In this work, we confirmed their effective contri-bution in the fruity perception in young red wines by evaluating the effect of their depletion by chemical and sensorial analyses. As previously reported, two pairs of esterases respectively en-coded by the paralogue genes (ATF1, ATF2) and (EEB1 and EHT1) are mostly involved in the bi-osynthesis of Acetate of Higher alcohols and Fatty Acids Ethyl Esters. However, those esterases have a moderate effect on the biosynthesis of Substituted Ethyl Esters that depends to another pair of genes, MGL2 and YJU3 encoding for mono-acyl lipases. These new findings complete our un-derstanding of esters metabolism in the context of wine alcoholic fermentation. In order to evaluate the sensorial impact of esters we attempted to produce a red wine without esters by generating a multiple deletion strain. Surprisingly, we failed to abolish all the esterase activities revealing unsuspected physiological consequences of ester biosynthesis routes. A preliminary RNA-seq analysis depicted the overall impact of the multiple deletion of ATF1, ATF2, EEB1 and EHT1 that triggers the expression shift of 1124 genes involved in nitrogen and lipid metabolism but also chromatin organization and histone acetylation, suggesting an unsuspected regulatory role of ester metabolism
ARTICLE | doi:10.20944/preprints201806.0131.v1
Subject: Life Sciences, Molecular Biology Keywords: histone demethylase inhibitors; DNA damage; epigenetic drugs; breast cancer
Online: 8 June 2018 (12:29:10 CEST)
Background: KDM5 enzymes are H3K4 specific histone demethylases involved in transcriptional regulation and DNA repair. These proteins are over-expressed in different kinds of cancer, including breast, prostate and bladder carcinoma, with positive effects on cancer proliferation and chemo-resistance. For these reasons, these enzymes are potential therapeutic cancer targets. Methods: In the present study, we analyzed the effects of three different inhibitors of KDM5 enzymes in MCF-7 breast cancer cells over-expressing JARID1B. In particular we tested H3K4 demethylation (western blot); target gene transcription (RNAseq and real time PCR); radio-sensitivity (citoxicity and clonogenic assays) and damage accumulation (kinetics of H2AX phosphorylation). Results: we show that two compounds with completely different chemical structure can selectively inhibit KDM5 enzymes and that both compounds are capable of increasing sensitivity of breast cancer cells to ionizing radiation and H2AX phosphorylation. Conclusions: These findings confirm the involvement of H3K4 specific demethylases in DNA damage signaling and repair and suggest new strategies for the therapeutic use of their inhibitors.
REVIEW | doi:10.20944/preprints202105.0476.v1
Subject: Biology, Anatomy & Morphology Keywords: Histone Methylation, DNA repair, homologous recombination, Non homologous end joining
Online: 20 May 2021 (10:26:07 CEST)
Packaging of the eukaryotic DNA genome with histone and other proteins forms a chromatin structure that regulates the outcome of all DNA mediated processes. The cellular pathways that ensure genomic stability detect and repair DNA damage through mechanisms which are critically dependent upon chromatin structures established by histones and, particularly, transient histone post-translational modifications . Though subject to a range of modifications, histone methylation is especially crucial for DNA damage repair as the methylated histones often form platforms for subsequent repair protein binding at damaged sites. In this review, we highlight and discuss how histone methylation impacts the maintenance of genome integrity through effects related to DNA repair and repair pathway choice.
REVIEW | doi:10.20944/preprints201803.0004.v1
Subject: Life Sciences, Molecular Biology Keywords: hypoxia; chromatin; transcriptional repression; repressor complexes; JmjC; histone methylation; HIF
Online: 1 March 2018 (06:36:57 CET)
Hypoxia, or reduced oxygen availability, has been studied extensively for its ability to activate specific genes. Hypoxia induced gene expression is mediated by the HIF transcription factors, although not exclusively so. Despite the great knowledge on the mechanisms by which hypoxia activates genes, much less is known about how hypoxia promotes gene repression. In this review, we discuss the potential mechanisms underlying hypoxia-induced transcriptional repression responses. We highlight HIF-dependent and independent mechanisms, but also the potential roles of dioxygenases with functions at the nucleosome and DNA level. Finally, we discuss recent evidence regarding the involvement of transcriptional repressor complexes in hypoxia.
Subject: Medicine & Pharmacology, Allergology Keywords: chaetocin, tazemetostat, ionizing radiation, doxorubicin, DNA repair, γH2AX, 53BP1, histone H4.
Online: 8 April 2021 (11:09:36 CEST)
Chromatin is dynamically remodeled to adapt to all DNA-related processes, including DNA damage responses (DDR). This adaptation requires DNA and histone epigenetic modifications, which are mediated by several types of enzymes; among them are lysine methyltransferases (KMTs). Methods: KMT inhibitors, chaetocin and tazemetostat (TZM), were used to study their role in the DDR induced by ionizing radiation or doxorubicin in two human sarcoma cells lines. The effect of these KMT inhibitors was tested by the analysis of chromatin epigenetic modifications, H4K16ac and H4K20me2. DDR was monitored by the formation of γH2AX, MDC1, NBS1 and 53BP1 foci, and the induction of apoptosis. Results: Chaetocin and tazemetostat treatments caused a significant increase of H4K16 acetylation, associated with chromatin relaxation; and increased DNA damage, detected by the labeling of free DNA-ends. These inhibitors significantly reduced H4K20 dimethylation levels in response to DNA damage and impaired the recruitment of 53BP1, but not of MDC1 and NBS1, at DNA damaged sites. This modification of epigenetic marks prevents DNA repair by the NHEJ pathway and leads to cell death. Conclusion: KMT inhibitors can function as sensitizers to DNA damage-based therapies and be used in novel synthetic lethality strategies for sarcoma treatment.
Subject: Medicine & Pharmacology, Allergology Keywords: DNA methylation; histone code; microRNA; nanoparticles; noncoding RNA; pulmonary arterial hypertension
Online: 4 November 2020 (10:07:24 CET)
Arterial wall remodeling underlies increased pulmonary vascular resistance and right heart failure in pulmonary arterial hypertension (PAH). None of the established vasodilator drug therapies for PAH prevents or reverses established arterial wall thickening, stiffening and hypercontractility. Therefore, new approaches are needed to achieve long-acting prevention and reversal of occlusive pulmonary vascular remodeling. Several promising new drug classes are emerging from better understanding of pulmonary vascular gene expression programs. In this review potential epigenetic targets for small molecules and oligonucleotides will be described. Most are in preclinical studies aimed at modifying growth of vascular wall cells in vitro or normalizing vascular remodeling in PAH animal models. Initial success with lung-directed delivery of oligonucleotides targeting microRNAs suggests other epigenetic mechanisms might also be suitable drug targets. Those targets include DNA methylation, proteins of the chromatin remodeling machinery and long noncoding RNAs, all of which act as epigenetic regulators of vascular wall structure and function. Progress in testing small molecules and oligonucleotide-based drugs in PAH models is summarized.
ARTICLE | doi:10.20944/preprints202201.0321.v1
Subject: Life Sciences, Molecular Biology Keywords: Periodontitis; Tooth movement; Obesity; Palmitic Acid; Histone Modification; Inflammation; COX2/PGE2; IL10
Online: 21 January 2022 (12:50:31 CET)
The interrelationship between periodontal disease, obesity-related hyperlipidemia and mechanical forces as well as their modulating effects on the epigenetic profile of periodontal ligament (PdL) cells are assumed to be remarkably complex. The PdL serves as connective tissue between teeth and alveolar bone for pathogen defense and inflammatory response to mechanical stimuli occurring during tooth movement. Altered inflammatory signaling could promote root resorption and tooth loss. Hyperinflammatory COX2/PGE2 signaling was reported for human PdL fibroblasts (HPdLF) concomitantly stressed with P. gingivalis lipopolysaccharides and compressive force after exposure to palmitic acid (PA). The aim of this study was to investigate to what extent this is modulated by global and gene-specific changes in histone modifications. Quantitative expression of epigenetic key players and global H3Kac as well as H3K27me3 levels were evaluated in dual stressed HPdLF exposed to PA revealing a decreased force-related reduction in repressive H3K27me3. UNC1999-induced H3K27me3 inhibition reversed the hyperinflammatory response of dual-stressed PA-cultures characterized by COX2 expression, PGE2 secretion and THP1 adhesion. Reduced expression of the anti-inflammatory cytokine IL10 and increased association of H3K27me3 at its promoter-associated sites were reversed by inhibitor treatment. Thus, the data highlight an important epigenetic interplay between different stimuli to which the PdL is exposed.
ARTICLE | doi:10.20944/preprints202010.0215.v1
Subject: Life Sciences, Biochemistry Keywords: epigenetic; histone; posttranslational modifications; T cells; influenza; FTICR; top-down; mass spectrometry
Online: 12 October 2020 (09:46:20 CEST)
T cell function is determined by transcriptional networks that are regulated by epigenetic programming via posttranslational modifications (PTMs) of histone proteins and DNA. Bottom-up mass spectrometry (MS) can identify histone PTMs, whereas intact protein analysis with high-field Fourier transform ion cyclotron resonance MS (FTICR-MS) can detect species missed by bottom-up approaches. We used high-resolution reversed-phase liquid chromatography (RPLC) FTICR-MS, alternating electron transfer dissociation (ETD) and collision-induced dissociation (CID) on precursor ions to maximize fragmentation of uniquely modified species. First online RPLC separation sorted histone families then weak cation exchange hydrophilic interaction liquid chromatography (WCX-HILIC) separated species heavily clad in PTMs. Tentative PTM identifications were assigned by matching peptide masses to predicted theoretical masses that were verified with tandem MS. We used this innovative approach for Histone-intact protein PTM mapping (HiPTMap) and to quantify PTMs on core histones purified from CD8+ T cells directly isolated ex vivo post-influenza infection. Activation significantly reduced PTMs in vivo following influenza infection, histone maps changed as T cells migrated to infections, and T cells responding to secondary heterologous infections had significantly more PTMs enhancing transcriptional activation. Thus, HiPTMap identifies and quantifies PTMs on CD8+ T cell histones and determines their combinations in T cell states.
REVIEW | doi:10.20944/preprints202009.0693.v1
Subject: Medicine & Pharmacology, Allergology Keywords: chromatin; DNA methylation; epigenetics; histone modifications; metaboloepigenetics; miRNA; therapy; type 1 diabetes
Online: 28 September 2020 (17:48:05 CEST)
Type 1 diabetes (T1D) is an autoimmune condition where the body’s immune cells destroy their insulin-producing pancreatic beta-cells leading to dysregulated glycaemia. Individuals with T1D control their blood glucose through exogenous insulin replacement therapy, often using multiple daily injections or pumps. However, failure to accurately mimic intrinsic glucose regulation results in glucose fluctuations and long-term complications impacting key organs such as the heart, kidneys, and/or the eyes. It is well-established that genetic and environmental factors contribute to the initiation and progression of type 1 diabetes, but recent studies show that epigenetic modifications are also important. Here, we discuss key epigenetic modifications associated with type 1 diabetes pathogenesis and discuss how recent research is finding ways to harness epigenetic mechanisms to prevent, reverse, or manage type 1 diabetes.
ARTICLE | doi:10.20944/preprints201908.0032.v1
Subject: Life Sciences, Molecular Biology Keywords: aging; skeletal muscle; sarcopenia; frailty; chromatin; epigenetic changes; histone modifications; Nothobranchius furzeri
Online: 2 August 2019 (12:17:03 CEST)
Aging associates with progressive loss of skeletal muscle function leading up to sarcopenia, a process characterized by impaired mobility and weakening of muscle strength. Molecular mechanisms underpinning sarcopenia are still poorly characterized. Since aging associates with profound epigenetic changes, epigenetic landscape alteration analysis in the skeletal muscle promises to highlight molecular mechanisms of age-associated sarcopenia. The study was conducted exploiting the short-lived turquoise killifish Nothobranchius furzeri (Nfu), a relatively new model for aging studies. The epigenetic analysis suggested for a less accessible and more condensed chromatin in old Nfu skeletal muscle. Specifically, an accumulation of heterochromatin regions was observed as consequence of increased levels of H3K27me3, HP1alpha, polycomb complex subunits and senescence associated heterochromatic foci (SAHFs). Consistently, euchromatin histone marks, including H3K9ac, decreased. The integrative bioinformatics analysis of RNASeq and ChIPSeq, related to skeletal muscle of Nfu at different ages, revealed a down-modulation of genes involved in cell cycle, differentiation and DNA repair and an up-regulation of inflammation and senescence genes. Undoubtedly, more studies are needed to disclose the detailed mechanisms, but this approach revealed an unprecedented specific features of Nfu skeletal muscle aging, potentially associated with sarcopenia onset and consequent impairment of swimming and mobility typical of old Nfu.
ARTICLE | doi:10.20944/preprints202211.0273.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: intellectual disability; KAT6A syndrome; Lysine acetyltransferase 6 A; pantothenate; L-carnitine; histone acetylation
Online: 15 November 2022 (04:14:12 CET)
Autism Spectrum disorder (ASD) and intellectual disability (ID) are the most frequent develop-mental disorders with a prevalence between 3% and 5% of the population. In addition, both ASD and ID can be found in the same patient. Mutations in several genes involved in the epigenetic regulation of gene expression have been linked to different ID associated with ASD features including alterations of the ly-sine-acetyltransferase 6A (KAT6A) gene in KAT6A syndrome. KAT6A enzyme participates in a wide range of critical cellular functions such as chromatin remodeling, gene expression, protein synthesis, cell metabolism, and replication. In this manuscript, we examined the pathophysiolog-ical alterations in fibroblasts derived from three patients harboring KAT6A mutations. We ad-dressed survival in stress medium, histone acetylation, protein expression patterns and tran-scriptome analysis as well as cell bioenergetics. In addition, we evaluated the therapeutic effec-tiveness of epigenetic modulators and mitochondrial boosting agents such as pantothenate and L-carnitine in correcting the mutant phenotype. Pantothenate and L-carnitine treatment increased histone acetylation and corrected protein and transcriptomic expression patterns in mutant KAT6A cells. Furthermore, cell bioenergetics of mutant cells was significantly improved. Our results suggest that pantothenate and L-carnitine can significantly correct the mutant phe-notype in cellular models of KAT6A syndrome.
REVIEW | doi:10.20944/preprints202206.0046.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: Acute myeloid leukemia; Pediatric; Epigenetics; DNA methylation; Histone modification; Non-coding RNAs; Therapy
Online: 3 June 2022 (10:59:28 CEST)
Acute myeloid leukemia (AML) is a hematological malignancy that is the culmination of genetic and epigenetic alterations in the hematopoietic progenitor cells, leading to uncontrolled proliferation at the expense of normal hematopoiesis and bone marrow exhaustion. Although the outcomes for pediatric AML have improved in recent decades, at least one third of children still have relapses. Recent studies have notably highlighted the important role of dysregulated epi-genetic mechanisms in myeloid leukemogenesis. Epigenetic modifications are frequently reversible compared to genetic alterations, thus providing opportunities for targeted epigenetic therapy. In this review, we summarize the landscape of epigenetic alterations and the progress to date in epigenetic targeted therapy, and focus on the future role of epigenetic abnormalities in predicting relapse and the precision therapy in pediatric AML.
REVIEW | doi:10.20944/preprints202007.0516.v1
Subject: Medicine & Pharmacology, Other Keywords: Megakaryocyte, IFITM3, VWF, ADAMTS13, emperipolesis, self-association, unfractionated heparin (UFH), histone, NETs, Thrombin
Online: 22 July 2020 (11:03:08 CEST)
COVID-19 thromboembolic disease has brought all of us back to the drawing board. In COVID-19, pre-existing activated endothelium with increased Von Willebrand factor (VWF), low density lipoprotein (LDL) promoting “self-association” and “sticking” of long VWF strings to the vascular endothelial wall, suppressed ADAMTS13 cleavage of VWF, hypoxia induced upregulation and activation of VWF, fibrous network from neutrophil extracellular traps (NETs) with free DNA and histone, all appear to be initiating the thrombogenesis. Worsening complement activation, cytokine storm and resulting endothelial destruction, unregulated thrombogenesis leads to vascular occlusions and hypoxia. At this stage, the presence of abundant extracellular DNA, histone and -defensins appears worse than the SARS-CoV-2 itself. Previously observed in vitro mechanisms like histone “auto-activating” prothrombin, histone activated platelets generating thrombin without FXII, thrombin and plasmin cleaving complement C5 appears highly likely in COVID-19. Megakaryocytes are actively producing platelets in the lungs and appear to play a major role in thrombogenesis of COVID-19 raising suspicion of emperipolesis. This focused review is a compilation of my observations in relation to the pathophysiology of the intravascular environment, mainly in COVID-19 lungs. Pathophysiology based clinical trials are paramount in reducing morbidity and mortality in COVID-19.
REVIEW | doi:10.20944/preprints201710.0185.v3
Subject: Life Sciences, Biochemistry Keywords: epigenome; DNA modification; cytosine methylation; gene regulation; histone modification; 5-methylcytosine; stress response
Online: 25 December 2017 (09:43:03 CET)
Genome-wide epigenetic changes in plants are being reported during the development and environmental stresses, which are often correlated with gene expression at the transcriptional level. Sum total of the biochemical changes in nuclear DNA, post-translational modifications in histone proteins and variations in the biogenesis of non-coding RNAs in a cell is known as epigenome. These changes are often responsible for variation in expression of the gene without any change in the underlying nucleotide sequence. The changes might also cause variation in chromatin structure resulting into the changes in function/activity of the genome. The epigenomic changes are dynamic with respect to the endogenous and/or environmental stimuli which affect phenotypic plasticity of the organism. Both, the epigenetic changes and variation in gene expression might return to the pre-stress state soon after withdrawal of the stress. However, a part of the epigenetic changes may be retained which is reported to play role in acclimatization, adaptation as well as in the evolutionary processes. Understanding epigenome-engineering for improved stress tolerance in plants has become essential for better utilization of the genetic factors. This review delineates the importance of epigenomics towards possible improvement of plant’s responses to environmental stresses for climate resilient agriculture.
REVIEW | doi:10.20944/preprints202211.0140.v1
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: Diffuse Intrinsic PontineDiffuse Intrinsic Pontine Glioma; DIPG; pediatric tumors; cancer; CAR-T; pons; histone mutation
Online: 8 November 2022 (02:57:43 CET)
Diffuse intrinsic pontine glioma (DIPG) is recognized as a pediatric brainstem cancer with a 0% survival rate. On a molecular basis, DIPG commonly results from mutations in histone H3, specifically a mutation in the H3K27M gene, that promotes tumorigenesis and results in presentation of this fatal brainstem tumor. DIPG is challenging to treat, as surgical intervention is inefficacious due to the location where the glioma resides. To date, traditional treatments such as radiation, chemotherapy, and immunotherapy have not increased survival rates and have only been successful at relieving symptoms. Future therapeutic approaches such as proton beam radiation, Chimeric Antigen Receptor T Cell (CAR-T) immunotherapy, and alternative epigenetic pharmaceuticals are under investigation for potential benefits. Various clinical trials have also explored these treatment procedures to discover potential increases in survival rates in both animal and human studies. In this review, we will evaluate the pathology and molecular characteristics of DIPG, the current and future approaches to DIPG treatment; and, lastly, we will discuss clinical trials that have been completed to develop successful treatment options.
REVIEW | doi:10.20944/preprints202111.0164.v1
Subject: Life Sciences, Molecular Biology Keywords: SETMAR; Metnase; H3K36me2; Hsmar1; non-homologous end joining repair; NHEJ; transposase; transposable elements; histone; methyltransferase
Online: 9 November 2021 (11:30:21 CET)
SETMAR is a protein lysine methyltransferase that is involved in several DNA processes, including DNA repair via the non-homologous end joining (NHEJ) pathway, regulation of gene expression, illegitimate DNA integration, and DNA decatenation. However, SETMAR is an atypical protein lysine methyltransferase since in anthropoid primates, the SET domain is fused to an inactive DNA transposase. The presence of the DNA transposase domain confers to SETMAR a DNA binding activity towards the remnants of its transposable element, which has resulted in the emergence of a gene regulatory function. Both the SET and the DNA transposase domains are involved in the different cellular roles of SETMAR, indicating the presence of novel and specific functions in anthropoid primates. In addition, SETMAR is dysregulated in different types of cancer, indicating a potential pathological role. While some light has been shed on SETMAR functions, more research and new tools are needed to better understand the cellular activities of SETMAR and to investigate the therapeutic potential of SETMAR.
REVIEW | doi:10.20944/preprints202107.0602.v1
Subject: Biology, Anatomy & Morphology Keywords: epigenetic mechanisms of disease; fetal programming; obstructive sleep apnea; DNA methylation; histone modifications; chronic disease
Online: 27 July 2021 (11:45:08 CEST)
Pediatric obstructive sleep apnea (OSA) has significant negative effects on health and behavior in childhood including depression, failure to thrive, neurocognitive impairment, and behavioral issues. It is strongly associated with an increased risk for chronic adult disease such as obesity and diabetes, accelerated atherosclerosis, and endothelial dysfunction. Accumulating evidence suggests that adult-onset non-communicable diseases may originate from early life through a process by which an insult applied at a critical developmental window causes long-term effects on the structure or function of an organism. Recently, much attention has been paid to the role of epigenetic mechanisms in the pathogenesis of adult disease susceptibility. Epigenetic mechanisms that influence adaptive variability include histone modifications, non-coding RNAs, and DNA methylation. This review will highlight what is currently known about the phenotypic associations of epigenetic modifications in pediatric OSA and will emphasize the importance of epigenetic changes as both modulators of chronic disease and potential therapeutic targets.
REVIEW | doi:10.20944/preprints202103.0291.v1
Subject: Biology, Anatomy & Morphology Keywords: secondary epimutations; repeat associated diseases; genetic editing; epigenetic editing; transcriptional editing; DNA methylation; histone modifications
Online: 10 March 2021 (16:14:10 CET)
Epimutations are the cause of a considerable number of genetically inherited conditions in humans. All result from the mis-expression of genes due to epigenetic changes that are triggered by an underlying heritable mutation. The correction of these epigenetic defects in the context of epigenetically regulated diseases constitutes a good paradigm to probe the fundamental mechanisms underlying the development of these diseases, and the molecular basis for the establishment, maintenance and regulation of epigenetic modifications in general. Here, we review current applications of key editing tools to address the epigenetic aspects of these diseases by focusing on epimutations caused by, or relate to repetitive elements, primarily unstable noncoding repeat expansions. For each approach we summarize the efforts conducted to date, highlight their contribution to a better understanding of the molecular basis of epigenetic mechanisms, describe the limitations of each approach and suggest perspectives for further exploration in this field.
REVIEW | doi:10.20944/preprints202011.0029.v1
Subject: Life Sciences, Biochemistry Keywords: Oxadiazoles; Bioactive heterocyclics; anticancer agents; Telomerase; Carbonic anhydrase; Histone deacetylase; Kinases; Tubulin; DNA; G-quadruplex.
Online: 2 November 2020 (11:18:22 CET)
Nowadays, an increasing number of heterocyclic-based drugs found application in medicinal chemistry and, in particular, as anticancer agents. In this context, oxadiazoles, five-membered aromatic rings, emerged for their interesting biological properties. Modification of oxadiazole scaffolds represents a valid strategy to increase their anticancer activity, especially on 1,2,4 and 1,3,4 regioisomers. In the last years, an increasing number of oxadiazole derivatives, with remarkable cytotoxicity for several tumor lines, were identified. Structural modifications, that ensure higher cytotoxicity towards malignant cells, represent a solid starting point in the development of novel oxadiazoles-based drugs. To increase the specificity of this strategy, outstanding oxadiazole scaffolds have been designed to selectively interact with biological targets, including enzymes, globular proteins and nucleic acids, showing more promising antitumor effects. In the present work, we aim to provide a comprehensive overview of the anticancer activity of these heterocycles, describing their effect on different targets and highlighting how their structural versatility has been exploited to modulate their biological properties.
REVIEW | doi:10.20944/preprints202003.0290.v1
Subject: Life Sciences, Molecular Biology Keywords: Histone PTM; RNA Polymerase II; ChIP-seq; chromatin; epigenetics; transcriptional interference; plant; Transcription Cycle; Transcription
Online: 18 March 2020 (17:14:28 CET)
Post-translational modifications (PTMs) of histone residues shape the landscape of gene expression by modulating the dynamic process of RNAPII transcription. The contribution of particular histone modifications to the definition of distinct RNAPII transcription stages remains poorly characterized in plants. Chromatin Immuno-precipitation combined with next-generation sequencing (ChIP-seq) resolves the genomic distribution of histone modifications. Here, we review histone PTM ChIP-seq data in Arabidopsis thaliana and find support for a Genomic Positioning System (GPS) that guides RNAPII transcription. We review the roles of histone PTM “readers”, “writers” and “erasers”, with a focus on the regulation of gene expression and biological functions in plants. The distinct functions of RNAPII transcription during the plant transcription cycle may in part rely on the characteristic histone PTMs profiles that distinguish transcription stages.
REVIEW | doi:10.20944/preprints201910.0021.v1
Subject: Life Sciences, Molecular Biology Keywords: PGC-1α; exercise; metabolism; epigenetics; histone modification; DNA methylation; micro RNA; gene regulation; thermogenesis; metabolic diseases
Online: 2 October 2019 (06:23:31 CEST)
Epigenetic changes are a hallmark of short- and long-term transcriptional regulation, and hence instrumental in the control of cellular identity and plasticity. Epigenetic mechanisms leading to changes in chromatin structure, accessibility for recruitment of transcriptional complexes, and interaction of enhancers and promoters all contribute to acute and chronic adaptations of cells, tissues and organs to internal and external perturbations. Similarly, the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is activated by stimuli that alter the cellular energetic demand, and subsequently controls complex transcriptional networks responsible for cellular plasticity. It thus is of no surprise that PGC-1α is under the control of epigenetic mechanisms, and constitutes a mediator of epigenetic changes in various tissues and contexts. In this review, we summarize the current knowledge of the link between epigenetics and PGC-1α in health and disease.
REVIEW | doi:10.20944/preprints202210.0083.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: epigenetics; TRP channels; TRPA1; pain transmission; neuropathic pain; neurogenic inflammation; migraine; DNA methylation; histone modification; micro RNA
Online: 7 October 2022 (15:21:34 CEST)
Background: Transient receptor potential cation channel subfamily A member 1 (TRPA1) is expressed in trigeminal neurons and brain regions important in migraine pathogenesis and is activated by many migraine triggers. Epigenetic regulation of TRPA1 expression is important in pain transmission and neurogenic inflammation.Findings: TRPA1 channels change noxious stimuli into pain signals with the involvement of epigenetic regulation, including DNA methylation, histone modifications, and effects of micro RNAs (miRNAs) and long non-coding RNAs. TRPA1 may change epigenetic profile of many pain-related genes as it may modify enzymes establishing the epigenetic profile and expression of non-coding RNAs. TRPA1 may induce the release of calcitonin gene related peptide (CGRP), from trigeminal neurons and dural tissue. Therefore, epigenetic regulation of TRPA1 may play a role in efficacy and safety of anti-migraine therapies targeting TRP channels and CGRP. TRPA1 is also involved in neurogenic inflammation, important in migraine. The fundamental role of TRPA1 in inflammatory pain transmission may be epigenetically regulated. Conclusions: Epigenetic connections of TRPA1 may play a role in efficacy and safety of anti-migraine therapy targeting TRP channels or CGRP and they should be further explored for efficient and safe antimigraine treatment.
REVIEW | doi:10.20944/preprints202001.0030.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: histone deacetylase 6 inhibitor; personalized treatment; heat shock protein 90α; leukemia stem cells; imatinib resistance; targeted therapy
Online: 4 January 2020 (06:18:22 CET)
Imatinib became the standard treatment for chronic myeloid leukemia (CML) about 20 years ago, which was a major breakthrough in stabilizing the pathology and improving the quality of life of patients. However, the emergence of resistance to imatinib and other tyrosine kinase inhibitors leads researchers to characterize new therapeutic targets. Several studies have highlighted the role of histone deacetylase 6 (HDAC6) in various pathologies, including cancer. This protein effectively intervenes in cellular activities by its primarily cytoplasmic localization. In this review, we will discuss the molecular characteristics of the HDAC6 protein, as well as its overexpression in CML leukemic stem cells, which make it a promising therapeutic target for the treatment of CML.
TECHNICAL NOTE | doi:10.20944/preprints202111.0256.v1
Subject: Biology, Other Keywords: planarian; maceration; high-content fluorescence microscopy; formaldehyde fixation; RNA FISH; immunocytochemistry; BrdU; phospho-histone H3; tyramide signal amplification
Online: 15 November 2021 (11:44:53 CET)
High-content fluorescence microscopy combines the efficiency of high-throughput techniques with the ability to extract quantitative information from biological systems. The planarian community has developed sensitive and robust assays for whole animals, yet cell based assays, despite their practical aspects, have not been explored to the same extent. Here we describe a modular collection of detailed protocols adapted for fixed planarian cells that enable multiplexed measurements of biomarkers in microwell plates. Methods include the detection of RNA transcripts by RNA fluorescent in situ hybridization combined with tyramide signal amplification using hapten-labeled riboprobes. In addition, immunocytochemical protocols for quantifying proliferating cells by the detection of phosphorylated histone H3 as well as 5-bromo-2'-deoxyuridine incorporation into the nuclear genome are described. The assays are compatible with planarians of virtually any size, as the tissue is disaggregated into a single cell suspension before fixation and staining. By sharing many reagents with established planarian whole mount staining protocols, preparation of samples for high-content microscopy adoption requires little additional investment. Recommendations for successful experimental workflows and common sources of errors are discussed.
REVIEW | doi:10.20944/preprints201807.0246.v2
Subject: Life Sciences, Molecular Biology Keywords: epigenetics, rehabilitation, DNA methylation, histone modification, HDAC, exercise, health span, heart failure, neurodegeneration, cancer, lung fibrosis, bone formation.
Online: 27 August 2018 (15:58:21 CEST)
A large body of evidence reports about the positive effects of physical activity in pathophysiological conditions associated with aging. Physical exercise, alone or in combination with other medical therapies, unquestionably causes reduction of symptoms in chronic non-transmissible diseases often leading to significant amelioration or complete healing. The molecular basis of this exciting outcome, however, remain largely obscure. Epigenetics, exploring at the interface between environmental signals and the remodelling of chromatin structure, promises to shed light on this intriguing matter possibly contributing to the identification of novel therapeutic targets. In this review, we shall focalize on the role of sirtuins (Sirts) a class III histone deacetylases (HDACs) which function has been frequently associated, often with a controversial role, to the pathogenesis of aging-associated pathophysiological conditions including cancer, cardiovascular, muscular, neurodegenerative, bones and respiratory diseases. Numerous studies, in fact, demonstrate that Sirt-dependent pathways are activated upon physical and cognitive exercises linking mitochondrial function, DNA structure remodelling and gene expression regulation to designed medical therapies leading to tangible beneficial outcomes. However, in similar conditions, other studies assign to sirtuins a negative pathophysiological role. In spite of this controversial effect, it is doubtless that studying sirtuins in chronic diseases might lead to an unprecedented improvement of life quality in the elderly.
ARTICLE | doi:10.20944/preprints201912.0076.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: H3K27M; DIPG; p53; APR-246; Jumonji family histone demethylases; GSK-J4, radiation; DNA damage repair; glutathione depletion; oxidative stress induction
Online: 6 December 2019 (04:34:45 CET)
Diffuse intrinsic pontine glioma (DIPG) is an aggressive pediatric brainstem tumor with a 5-year survival of <1%. Up to 80% of DIPG tumors contain a specific K27M mutation in one of two genes encoding histone H3 (H3K27M). Furthermore, p53 mutations found in >70-80% of H3K27M DIPG, and mutant p53 status is associated with a decreased response to radiation treatment and worse overall prognosis. Recent evidence indicates that H3K27M mutation disrupts tri-methylation at H3K27 leading to aberrant gene expression. Jumonji family histone demethylases collaborates with H3K27 mutation in DIPG by erasing H3K27 trimethylation and thus contributing to derepression of genes involved in tumorigenesis. Since the first line treatment for pediatric DIPG is fractionated radiation, we investigated the effects of Jumonji demethylase inhibition with GSK-J4, and mutant p53 targeting/oxidative stress induction with APR-246, on radio-sensitization of human H3K27M DIPG cells. Both APR-246 and GSK-J4 displayed growth inhibitory effects as single agents in H3K27M DIPG cells. Furthermore, both of these agents elicited mild radiosensitizing effects in human DIPG cells (sensitizer enhancement ratios (SERs) of 1.12 and 1.35, respectively; p<0.05). Strikingly, a combination of APR-246 and GSK-J4 displayed a significant enhancement of radiosensitization, with SER of 1.50 (p<0.05) at sub-micro-molar concentrations of the drugs (0.5 μM). The molecular mechanism of the observed radiosensitization appears to involve DNA damage repair deficiency triggered by APR-246/GSK-J4, leading to the induction of apoptotic cell death. Thus, a therapeutic approach of combined targeting of mutant p53, oxidative stress induction, and Jumonji demethylase inhibition with radiation in DIPG warrants further investigation.
REVIEW | doi:10.20944/preprints201703.0125.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: Extracellular vesicles (EVs); Peptidylarginine deiminases (PADs); Chlor-amidine (Cl-Am); cancer; neurodegeneration; deimination; cytoskeleton; induced pluripotent stem cells (iPSCs); histone H3; epigenetics
Online: 16 March 2017 (17:54:15 CET)
Extracellular vesicle (EV) release, which occurs in most eukaryotic cells, has recently been associated with peptidylarginine deiminase (PAD)-driven protein deimination. Evidence points to the involvement of deiminated cytoskeletal proteins and changes in histone deimination. Both PADs and EVs are associated with various pathologies including cancers, autoimmune and neurodegenerative diseases. The elevated PAD expression observed in cancers may contribute to increase in EV shedding observed from cancer cells, contributing to cancer progression. Similarly, elevated PAD expression observed in neurodegenerative diseases may cause increased EV shedding and spread of neurodegenerative EV cargo, contributing to disease progression and pathologies. Pharmacological inhibition of PAD-mediated deimination using pan-PAD inhibitor Cl-amidine, reduced cellular EV release in prostate cancer cells, rendering them significantly more susceptible to chemotherapeutic drugs. Studies on models of central nervous system damage have demonstrated critical functional roles for PADs and neuroprotective effects using PAD inhibitors in vivo, while human neurodegenerative iPSC in vitro models showed evidence of increased protein deimination. Besides using refined PAD inhibitors to selectively manipulate EV biogenesis for novel combination therapies in cancer treatment, we also speculate how EV biogenesis could be targeted via the newly identified PAD-pathway to ameliorate neurodegenerative disease progression.