Genome-wide identification, phylogenetic classification of histone acetyltransferase genes, and their expression analysis in sugar beet (Beta vulgaris L.) under salt stress.

MAIN CONCLUSION: This study identified seven histone acetyltransferase-encoding genes (HATs) from Beta vulgaris L. (sugar beet) genome through bioinformatics tools and analyzed their expression profiles under salt stress. Sugar beet HATs are phylogenetically divided into four families: GNAT, MYST, CBP, and TAFII250. The BvHAT genes were differentially transcribed in leaves, stems, and roots of B. vulgaris salt-resistant (Casino) and -sensitive (Bravo) cultivars under salt stress. Histone acetylation is regulated by histone acetyltransferases (HATs), which catalyze ɛ-amino bond formation between lysine residues and acetyl groups with a cofactor, acetyl-CoA. Even though the HATs are known to participate in stress response and development in model plants, little is known about the functions of HATs in crops. In sugar beet (Beta vulgaris L.), they have not yet been identified and characterized. Here, an in silico analysis of the HAT gene family in sugar beet was performed, and their expression patterns in leaves, stems, and roots of B. vulgaris were analyzed under salt stress. Salt-resistant (Casino) and -sensitive (Bravo) beet cultivars were used for gene expression assays. Seven HATs were identified from sugar beet genome, and named BvHAG1, BvHAG2, BvHAG3, BvHAG4, BvHAC1, BvHAC2, and BvHAF1. The HAT proteins were divided into 4 groups including MYST, GNAT (GCN5, HAT1, ELP3), CBP and TAFII250. Analysis of cis-acting elements indicated that the BvHAT genes might be involved in hormonal regulation, light response, plant development, and abiotic stress response. The BvHAT genes were differentially expressed in leaves, stems, and roots under control and 300 mM NaCl. In roots of B. vulgaris cv. Bravo, the BvHAG1, BvHAG2, BvHAG4, BvHAF1, and BvHAC1 genes were dramatically expressed after 7 and 14 days of salt stress. Interestingly, the BvHAC2 gene was not expressed under both control and stress conditions. However, the expression of BvHAG2, BvHAG3, BvHAG4, BvHAC1, BvHAC2 genes showed a significant increase in response to salt stress in the roots of cv. Casino. This study provides new insights into the potential roles of histone acetyltransferases in sugar beet.

Pantothenate and L-Carnitine Supplementation Improves Pathological Alterations in Cellular Models of KAT6A Syndrome.

Mutations in several genes involved in the epigenetic regulation of gene expression have been considered risk alterations to different intellectual disability (ID) syndromes associated with features of autism spectrum disorder (ASD). Among them are the pathogenic variants of the lysine-acetyltransferase 6A (KAT6A) gene, which causes KAT6A syndrome. The 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 pathophysiological alterations in fibroblasts derived from three patients harboring KAT6A mutations. We addressed survival in a stress medium, histone acetylation, protein expression patterns, and transcriptome analysis, as well as cell bioenergetics. In addition, we evaluated the therapeutic effectiveness 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 partially corrected protein and transcriptomic expression patterns in mutant KAT6A cells. Furthermore, the cell bioenergetics of mutant cells was significantly improved. Our results suggest that pantothenate and L-carnitine can significantly improve the mutant phenotype in cellular models of KAT6A syndrome.

The histone lysine acetyltransferase HBO1 (KAT7) regulates hematopoietic stem cell quiescence and self-renewal.

The histone acetyltransferase HBO1 (MYST2, KAT7) is indispensable for postgastrulation development, histone H3 lysine 14 acetylation (H3K14Ac), and the expression of embryonic patterning genes. In this study, we report the role of HBO1 in regulating hematopoietic stem cell function in adult hematopoiesis. We used 2 complementary cre-recombinase transgenes to conditionally delete Hbo1 (Mx1-Cre and Rosa26-CreERT2). Hbo1-null mice became moribund due to hematopoietic failure with pancytopenia in the blood and bone marrow 2 to 6 weeks after Hbo1 deletion. Hbo1-deleted bone marrow cells failed to repopulate hemoablated recipients in competitive transplantation experiments. Hbo1 deletion caused a rapid loss of hematopoietic progenitors. The numbers of lineage-restricted progenitors for the erythroid, myeloid, B-, and T-cell lineages were reduced. Loss of HBO1 resulted in an abnormally high rate of recruitment of quiescent hematopoietic stem cells (HSCs) into the cell cycle. Cycling HSCs produced progenitors at the expense of self-renewal, which led to the exhaustion of the HSC pool. Mechanistically, genes important for HSC functions were downregulated in HSC-enriched cell populations after Hbo1 deletion, including genes essential for HSC quiescence and self-renewal, such as Mpl, Tek(Tie-2), Gfi1b, Egr1, Tal1(Scl), Gata2, Erg, Pbx1, Meis1, and Hox9, as well as genes important for multipotent progenitor cells and lineage-specific progenitor cells, such as Gata1. HBO1 was required for H3K14Ac through the genome and particularly at gene loci required for HSC quiescence and self-renewal. Our data indicate that HBO1 promotes the expression of a transcription factor network essential for HSC maintenance and self-renewal in adult hematopoiesis.

Garcinol-A Natural Histone Acetyltransferase Inhibitor and New Anti-Cancer Epigenetic Drug.

Garcinol extracted from Garcinia indica fruit peel and leaves is a polyisoprenylated benzophenone. In traditional medicine it was used for its antioxidant and anti-inflammatory properties. Several studies have shown anti-cancer properties of garcinol in cancer cell lines and experimental animal models. Garcinol action in cancer cells is based on its antioxidant and anti-inflammatory properties, but also on its potency to inhibit histone acetyltransferases (HATs). Recent studies indicate that garcinol may also deregulate expression of miRNAs involved in tumour development and progression. This paper focuses on the latest research concerning garcinol as a HAT inhibitor and miRNA deregulator in the development and progression of various cancers. Garcinol may be considered as a candidate for next generation epigenetic drugs, but further studies are needed to establish the precise toxicity, dosages, routes of administration, and safety for patients.

Evaluation of the effects of the T-type calcium channel enhancer SAK3 in a rat model of TAF1 deficiency.

The TATA-box binding protein associated factor 1 (TAF1) is part of the TFIID complex that plays a key role during the initiation of transcription. Variants of TAF1 are associated with neurodevelopmental disorders. Previously, we found that CRISPR/Cas9 based editing of the TAF1 gene disrupts the morphology of the cerebral cortex and blunts the expression as well as the function of the CaV3.1 (T-type) voltage gated calcium channel. Here, we tested the efficacy of SAK3 (ethyl 8'-methyl-2', 4-dioxo-2-(piperidin-1-yl)-2'H-spiro [cyclopentane-1, 3'-imidazo [1, 2-a] pyridine]-2-ene-3-carboxylate), a T-type calcium channel enhancer, in an animal model of TAF1 intellectual disability (ID) syndrome. At post-natal day 3, rat pups were subjected to intracerebroventricular (ICV) injection of either gRNA-control or gRNA-TAF1 CRISPR/Cas9 viruses. At post-natal day 21, the rat pups were given SAK3 (0.25 mg/kg, p.o.) or vehicle for 14 days (i.e. till post-natal day 35) and then subjected to behavioral, morphological, and molecular studies. Oral administration of SAK3 (0.25 mg/kg, p.o.) significantly rescued locomotion abnormalities associated with TAF1 gene editing. SAK3 treatment prevented the loss of cortical neurons and GFAP-positive astrocytes observed after TAF1 gene editing. In addition, SAK3 protected cells from apoptosis. SAK3 also restored the Brain-derived neurotrophic factor/protein kinase B/Glycogen Synthase Kinase 3 Beta (BDNF/AKT/GSK3ß) signaling axis in TAF1 edited animals. Finally, SAK3 normalized the levels of three GSK3ß substrates - CaV3.1, FOXP2, and CRMP2. We conclude that the T-type calcium channel enhancer SAK3 is beneficial against the deleterious effects of TAF1 gene-editing, in part, by stimulating the BDNF/AKT/GSK3ß signaling pathway.

Synergistic effects of pazopanib and hyperthermia against uterine leiomyosarcoma growth mediated by downregulation of histone acetyltransferase 1.

Pazopanib-a multitargeted tyrosine kinase inhibitor with prominent antiangiogenic effects-has shown promise in the treatment of soft-tissue sarcomas. Hyperthermia has been also applied as an adjunctive treatment to chemotherapy for these malignancies. Here, we show that pazopanib and hyperthermia act synergistically in inhibiting uterine leiomyosarcoma (LMS) cell growth. Compared with either treatment alone, the combination of pazopanib and hyperthermia exerted the highest antitumor activity in a xenograft model. Mechanistically, we found that combined treatment with pazopanib and hyperthermia inhibited histone acetyltransferase 1 (HAT1) expression in LMS cells. The Clock element on the HAT1 promoter was critical for pazopanib- and hyperthermia-induced HAT1 downregulation. Inhibition of HAT1-either by pazopanib and hyperthermia or through HAT1 silencing-was mediated by suppression of Clock. Accordingly, Clock protein reconstitution rescued both HAT1 levels and HAT1-mediated histone acetylation. Immunohistochemistry revealed a higher expression of HAT1 in uterine LMS than in leiomyomas (p = 0.007), with high HAT1 expression levels being associated with poor clinical outcomes (p = 0.007). We conclude that pazopanib and hyperthermia exert synergistic effects against LMS growth by inhibiting HAT1. Further preclinical studies on HAT1 as a potential drug target in uterine LMS are warranted, especially in combination with hyperthermia. KEY MESSAGES: Pazopanib and hyperthermia inhibit the growth of leiomyosarcoma. Their combined use inhibits HAT1 expression in leiomyosarcoma cells. The promoter Clock element is required for HAT1 downregulation. HAT1 expression is higher in leiomyosarcoma than in leiomyomas. An increased HAT1 expression is associated with poor clinical outcomes.

The epithelial zinc transporter ZIP10 epigenetically regulates human epidermal homeostasis by modulating histone acetyltransferase activity.

BACKGROUND: The skin is the first organ that manifests changes in response to zinc deficiency. However, the molecular mechanism underlying how zinc is involved in skin homeostasis, especially its epigenetic regulation, is largely unknown. OBJECTIVES: In this study we demonstrate the importance of zinc levels and the zinc transporter ZIP10 in the epigenetic maintenance of human epidermal homeostasis. METHODS: Adult human skin, including skin appendages, were stained with anti-ZIP10 antibody. Histone acetyltransferase (HAT) activity was assessed after treating human keratinocytes with ZIP10 small interfering (si)RNAs or the zinc chelator TPEN. ZIP10- or HAT-regulated genes were analysed based on limma bioinformatics analysis for keratinocytes treated with ZIP10 siRNAs or a HAT inhibitor, or using a public database for transcription factors. A reconstituted human skin model was used to validate the role of ZIP10 in epidermal differentiation and the functional association between ZIP10 and HAT. RESULTS: ZIP10 is predominantly expressed in the interfollicular epidermis, epidermal appendages and hair follicles. ZIP10 depletion resulted in epidermal malformations in a reconstituted human skin model via downregulation of the activity of the epigenetic enzyme HAT. This decreased HAT activity, resulting from either ZIP10 depletion or treatment with the zinc chelator TPEN, was readily restored by zinc supplementation. Through bioinformatics analysis for gene sets regulated by knockdown of SLC39A10 (encoding ZIP10) and HAT inhibition, we demonstrated that ZIP10 and HATs were closely linked with the regulation of genes related to epidermal homeostasis, particularly filaggrin and metallothionein. CONCLUSIONS: Our study suggests that ZIP10-mediated zinc distribution is crucial for epidermal homeostasis via HATs. Therefore, zinc-dependent epigenetic regulation could provide alternatives to maintaining healthy skin or alleviating disorders with skin barrier defects.

Elongator subunit 3 (ELP3) modifies ALS through tRNA modification.

Amyotrophic lateral sclerosis (ALS) is a fatal degenerative motor neuron disorder of which the progression is influenced by several disease-modifying factors. Here, we investigated ELP3, a subunit of the elongator complex that modifies tRNA wobble uridines, as one of such ALS disease modifiers. ELP3 attenuated the axonopathy of a mutant SOD1, as well as of a mutant C9orf72 ALS zebrafish model. Furthermore, the expression of ELP3 in the SOD1G93A mouse extended the survival and attenuated the denervation in this model. Depletion of ELP3 in vitro reduced the modified tRNA wobble uridine mcm5s2U and increased abundance of insoluble mutant SOD1, which was reverted by exogenous ELP3 expression. Interestingly, the expression of ELP3 in the motor cortex of ALS patients was reduced and correlated with mcm5s2U levels. Our results demonstrate that ELP3 is a modifier of ALS and suggest a link between tRNA modification and neurodegeneration.

Combination Treatments with Luteolin and Fisetin Enhance Anti-Inflammatory Effects in High Glucose-Treated THP-1 Cells Through Histone Acetyltransferase/Histone Deacetylase Regulation.

Hyperglycemia leads to diabetes and its diabetic complications. In this study, we investigated the synergistic effects of luteolin and fisetin on proinflammatory cytokine secretion and its underlying epigenetic regulation in human monocytes exposed to hyperglycemic (HG) concentrations. Human monocytic cells (THP-1) were cultured under controlled (14.5 mM mannitol), normoglycemic (5.5 mM glucose), or HG (20 mM glucose) conditions in the absence or presence of the two phytochemicals for 48 h. Whereas HG conditions significantly induced histone acetylation, nuclear factor-kappa B (NF-κB) activation, interleukin 6, and tumor necrosis factor-α release from THP-1 cells; combination treatments with the two phytochemicals (500 nM fisetin, and l µM and 500 nM luteolin) suppressed NF-κB activity and inflammatory cytokine release. Fisetin, luteolin, and their combination treatments also significantly decreased the activity of histone acetyltransferase, a known NF-κB coactivator; inhibited reactive oxygen species production; and activated sirtuin (SIRT)1 and forkhead box O3a (FOXO3a) expressions (P < .05). Thus, combination treatments with the two phytochemicals inhibited HG condition-induced cytokine production in monocytes, through epigenetic changes involving NF-κB activation. We, therefore, suggest that combination treatments with luteolin and fisetin may be a potential candidate for the treatment and prevention of diabetes and its complications.

Altered gene expression of epigenetic modifying enzymes in response to dietary supplementation with linseed oil.

Recently we showed that 5% linseed oil (LSO) and 5% safflower oil (SFO) supplementation of cow's diets reduced milk fat yield by 30·38 and 32·42% respectively, accompanied by differential expression of genes and regulation by microRNAs (miRNA). This research communication addresses the hypothesis that epigenetic regulation could be involved in the observed milk fat reduction. Thus, this study investigated the gene expression pattern of major epigenetic modifying enzymes in response to dietary supplementation with LSO or SFO. Twenty-six Canadian Holstein cows in mid lactation were randomly assigned to two groups (13/group) and fed a control diet for 28 d (day -28 to -1) (control period- CP) followed by a treatment period (TP) (control diet supplemented with 5% LSO (LSO treatment) or 5% SFO (SFO treatment) of 28 d (day +1 to +28). After treatment, cows in the two groups were returned to the control diet for another 28 d (day +29 to +56) (post treatment period-PTP). Milk samples were collected on day -1 (CP), +7, +28 (TP) and +56 (PTP) for RNA isolation and measurement of the expression of thirteen epigenetic modifying genes including two DNA methytrasferases (DNMT1, DNMT3A), four histone acetylases (HAT1, KAT2A, KAT5 and CREBBP), five histone deacetylases (HDAC1, HDAC2, HDAC3, SIRT1 and SIRT2) and two histone methytransferases (EHMT2 and PRMT1) by qPCR. Linseed oil supplementation significantly repressed the expression of EHMT2, HDAC2 and HDAC3 on day +7 (P < 0·05) and KAT2A and SIRT2 on day +28 (P < 0·05) as compared with the control period (day -1) while SFO had no effect. When LSO was withdrawn, the expression of some of the genes increased slightly but did not reach control (day -1) levels at the end of the PTP. Our study demonstrated a significant role of LSO in the epigenetic regulation of fatty acid synthesis as compared to SFO. The effect of LSO may be related to its higher degree of unsaturation and might represent a different regulatory mechanism which needs further investigation.

Antioxidant-Rich Extract from Plantaginis Semen Ameliorates Diabetic Retinal Injury in a Streptozotocin-Induced Diabetic Rat Model.

Plantaginis semen, the dried ripe seed of Plantago asiatica L. or Plantago depressa Willd. (Plantaginaceae), has been traditionally used to treat blurred vision in Asia. The aim of this work was to investigate the effect of plantaginis semen ethanol extract (PSEE) on the amelioration of diabetic retinopathy (DR) in streptozotocin (STZ)-diabetic rats. PSEE has abundant polyphenols with strong antioxidant activity. PSEE (100, 200 or 300 mg/kg) was oral administrated to the diabetic rats once daily consecutively for 8 weeks. Oral administration of PSEE resulted in significant reduction of hyperglycemia, the diameter of the retinal vessels, and retinal vascular permeability and leukostasis in diabetic rats. In addition, PSEE administration increased the activities of superoxidase dismutase (SOD) and catalase (CAT), and glutathione peroxidase (GSH) level in diabetic retinae. PSEE treatment inhibited the expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α) and the phosphorylation of Akt without altering the Akt protein expression in diabetic retinae. PSEE not only down-regulated the gene expression of hypoxia-inducible factor-1α (TNF-α) and interleukin-1ß (IL-1ß), but also reduced ICAM-1 and VCAM-1 expression in diabetic retinae. Moreover, PSEE reduced the nuclear factor-κB (NF-κB) activation and corrected imbalance between histone deacetylases (HDAC) and histone acetyltransferases (HAT) activities in diabetic retinae. In conclusion, phenolic antioxidants extract from plantaginis semen has potential benefits in the prevention and/or progression of DR.

Autodisplay of Human Hyaluronidase Hyal-1 on Escherichia coli and Identification of Plant-Derived Enzyme Inhibitors.

Hyaluronan (HA) is the main component of the extracellular matrix (ECM). Depending on its chain size, it is generally accepted to exert diverse effects. High molecular weight HA is anti-angiogenic, immunosuppressive and anti-inflammatory, while lower fragments are angiogenic and inflammatory. Human hyaluronidase Hyal-1 (Hyal-1) is one of the main enzymes in the metabolism of HA. This makes Hyal-1 an interesting target. Not only for functional and mechanistic studies, but also for drug development. In this work, Hyal-1 was expressed on the surface of E. coli, by applying Autodisplay, to overcome formation of inactive "inclusion bodies". With the cells displaying Hyal-1 an activity assay was performed using "stains-all" dye. Subsequently, the inhibitory effects of four saponins and 14 plant extracts on the activity of surface displayed Hyal-1 were evaluated. The determined IC50 values were 177 µM for glycyrrhizic acid, 108 µM for gypsophila saponin 2, 371 µM for SA1657 and 296 µM for SA1641. Malvae sylvestris flos, Equiseti herba and Ononidis radix extracts showed IC50 values between 1.4 and 1.7 mg/mL. In summary, Autodisplay enabled the expression of functional human target protein Hyal-1 in E. coli and facilitated an accelerated testing of potential inhibitors.

Effects of scriptaid on the histone acetylation of buffalo oocytes and their ability to support the development of somatic cell nuclear transfer embryos.

The present study was undertaken to investigate the effect of scriptaid treatment on histone H3 on lysine 18 (H3K18) acetylation and relative expression levels of genes related to histone acetylation (HAT1, CBP, and p300) in buffalo oocytes during IVM. Meanwhile, the embryonic developmental ability of buffalo oocytes after SCNT was also examined. The H3K18 acetylation in oocytes increased from the germinal vesicle (GV) stage to the GV breakdown (GVBD) stage and arrived at a high acetylation level at the GVBD stage. Then, the H3K18 deacetylated completely at the metaphase I (MI) and acetylated again at the MII stage. However, addition of 500-nM scriptaid to the maturation medium resulted in a significant increase in the H3K18 acetylation at the MI stage. The expression profiles of genes related to histone acetylation (HAT1, CBP, and p300) in the meiosis stages of oocytes matured in the medium supplemented with 500-nM scriptaid were significantly higher than those of the oocytes matured in the medium without scriptaid (P < 0.05) with the exception of p300 at the GVBD stage. More SCNT embryos reconstructed with oocytes matured in the medium supplemented with 500-nM scriptaid developed to blastocysts (23.1%) in comparison with oocytes matured in the medium without scriptaid (13.8%, P < 0.05). These results indicate that scriptaid can increase the histone acetylation of buffalo oocytes during meiotic maturation and improve their ability to support the development of SCNT embryos.

BioID identifies novel c-MYC interacting partners in cultured cells and xenograft tumors.

The BioID proximity-based biotin labeling technique was recently developed for the characterization of protein-protein interaction networks [1]. To date, this method has been applied to a number of different polypeptides expressed in cultured cells. Here we report the adaptation of BioID to the identification of protein-protein interactions surrounding the c-MYC oncoprotein in human cells grown both under standard culture conditions and in mice as tumor xenografts. Notably, in vivo BioID yielded >100 high confidence MYC interacting proteins, including >30 known binding partners. Putative novel MYC interactors include components of the STAGA/KAT5 and SWI/SNF chromatin remodeling complexes, DNA repair and replication factors, general transcription and elongation factors, and transcriptional co-regulators such as the DNA helicase protein chromodomain 8 (CHD8). Providing additional confidence in these findings, ENCODE ChIP-seq datasets highlight significant coincident binding throughout the genome for the MYC interactors identified here, and we validate the previously unreported MYC-CHD8 interaction using both a yeast two hybrid analysis and the proximity-based ligation assay. In sum, we demonstrate that BioID can be utilized to identify bona fide interacting partners for a chromatin-associated protein in vivo. This technique will allow for a much improved understanding of protein-protein interactions in a previously inaccessible biological setting. BIOLOGICAL SIGNIFICANCE: The c-MYC (MYC) oncogene is a transcription factor that plays important roles in cancer initiation and progression. MYC expression is deregulated in more than 50% of human cancers, but the role of this protein in normal cell biology and tumor progression is still not well understood, in part because identifying MYC-interacting proteins has been technically challenging: MYC-containing chromatin-associated complexes are difficult to isolate using traditional affinity purification methods, and the MYC protein is exceptionally labile, with a half-life of only ~30 min. Developing a new strategy to gain insight into MYC-containing protein complexes would thus mark a key advance in cancer research. The recently described BioID proximity-based labeling technique represents a promising new complementary approach for the characterization of protein-protein interactions (PPIs) in cultured cells. Here we report that BioID can also be used to characterize protein-protein interactions for a chromatin-associated protein in tumor xenografts, and present a comprehensive, high confidence in vivo MYC interactome. This article is part of a Special Issue entitled: Protein dynamics in health and disease. Guest Editors: Pierre Thibault and Anne-Claude Gingras.

Changes in histone methylation and acetylation during microspore reprogramming to embryogenesis occur concomitantly with Bn HKMT and Bn HAT expression and are associated with cell totipotency, proliferation, and differentiation in Brassica napus.

In response to stress treatments, microspores can be reprogrammed to become totipotent cells that follow an embryogenic pathway producing haploid and double-haploid embryos which are important biotechnological tools in plant breeding. Recent studies have revealed the involvement of DNA methylation in regulating this process, but no information is available on the role of histone modifications in microspore embryogenesis. Histone modifications are major epigenetic marks controlling gene expression during plant development and in response to environmental changes. Lysine methylation of histones, accomplished by histone lysine methyltransferases (HKMTs), can occur on different lysine residues, with histone H3K9 methylation being mainly associated with transcriptionally silenced regions. In contrast, histone H3 and H4 acetylation is carried out by histone acetyltransferases (HATs) and is associated with actively transcribed genes. In this work, we analyzed 3 different histone epigenetic marks: dimethylation of H3K9 (H3K9me2) and acetylation of H3 and H4 (H3Ac and H4Ac) during microspore embryogenesis in Brassica napus by Western blot and immunofluorescence assays. The expression patterns of histone methyltransferase BnHKMT and histone acetyltransferase BnHAT genes have also been analyzed by qPCR. Our results revealed different spatial and temporal distribution patterns for methylated and acetylated histone variants during microspore embryogenesis and their similarity with the expression profiles of BnHKMT and BnHAT, respectively. The data presented suggest the participation of H3K9me2 and HKMT in embryo cell differentiation and heterochromatinization events, whereas H3Ac, H4Ac, and HAT would be involved in transcriptional activation, totipotency, and proliferation events during cell reprogramming and embryo development.

Genome-wide association study dissects the genetic architecture of seed weight and seed quality in rapeseed (Brassica napus L.).

Association mapping can quickly and efficiently dissect complex agronomic traits. Rapeseed is one of the most economically important polyploid oil crops, although its genome sequence is not yet published. In this study, a recently developed 60K Brassica Infinium(®) SNP array was used to analyse an association panel with 472 accessions. The single-nucleotide polymorphisms (SNPs) of the array were in silico mapped using 'pseudomolecules' representative of the genome of rapeseed to establish their hypothetical order and to perform association mapping of seed weight and seed quality. As a result, two significant associations on A8 and C3 of Brassica napus were detected for erucic acid content, and the peak SNPs were found to be only 233 and 128 kb away from the key genes BnaA.FAE1 and BnaC.FAE1. BnaA.FAE1 was also identified to be significantly associated with the oil content. Orthologues of Arabidopsis thaliana HAG1 were identified close to four clusters of SNPs associated with glucosinolate content on A9, C2, C7 and C9. For seed weight, we detected two association signals on A7 and A9, which were consistent with previous studies of quantitative trait loci mapping. The results indicate that our association mapping approach is suitable for fine mapping of the complex traits in rapeseed.

Proteostasis, an emerging therapeutic paradigm for managing inflammatory airway stress disease.

Airways stress diseases (ASDs), including chronic obstructive pulmonary disease (COPD), emphysema and asthma, are predicted to become the third leading cause of morbidity and mortality by 2020. An understanding and the treatment of these diseases will have a high impact on human health and the health system. An emerging area of heathspan impact is the link between ASDs and proteome homeostasis or 'proteostasis', a biological system comprised of > 2000 components that direct the generation, maintenance and removal of proteins to achieve normal function. Alpha-1 antitrypsin deficiency (αA1TD) aggregates activating extracellular folding stress pathways, dysregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and misprocessing by histone acetyltransferase (HAT)/histone deacetylase (HDAC) pathways represent key examples of proteostasis imbalance involved in ASDs. Common to these events in the lung is a chronic inflammatory response in response to nuclear factor-κB (NF-κB) signaling and protein folding stress associated with an excess of mucus secretion, tissue remodeling, peribronchiolar fibrosis, bronchoconstriction and aveolar destruction. All of these emergent properties of disease are a consequence of imbalance in the proteostasis system. Herein, we discuss the role of proteostasis and its consequences on lung pathophysiology in inflammatory ASDs, and suggest how manipulating the proteostasis network through pharmacological intervention of proteostasis pathways could provide multiple routes for the restoration of lung physiology.

Cytotoxic effects produced by arecoline correlated to epigenetic regulation in human K-562 cells.

Epigenetic effects are considered heritable but may also be modified by environmental factors. Arecoline (ARC), a major component of areca nut alkaloids, is an important environmental risk factor for oral cancer and hepatocellular carcinomain Taiwan. The aim of this study was to determine the influence of ARC on the epigenome. The mRNA expression of histone methyltransferases, acetyltransferases, and demethylases were assessed in K-562 cells following exposure to ARC. Results demonstrated that ARC produced changes in the expressions of several genes catalyzing histone methylation (Mll, Setdb1, and Suv39h2), acetylation (Atf2), and demethylation (JMJD6). Since H3K9 methylation is involved in maintaining the stability of heterochromatin structures and inactivating euchromatic gene expressions, data suggest that the ARC-induced epigenetic changes play a role in the mechanisms underlying chemical-mediated cytotoxicity and genotoxicity.

Grape seed extract regulates androgen receptor-mediated transcription in prostate cancer cells through potent anti-histone acetyltransferase activity.

Histone acetylation, which is regulated by histone acetyltransferases (HATs) and deacetylases, is an epigenetic mechanism that influences eukaryotic transcription. Significant changes in histone acetylation are associated with cancer; therefore, manipulating the acetylation status of key gene targets is likely crucial for effective cancer therapy. Grape seed extract (GSE) has a known protective effect against prostate cancer. Here, we showed that GSE significantly inhibited HAT activity by 30-80% in vitro (P < .05). Furthermore, we demonstrated significant repression of androgen receptor (AR)-mediated transcription by GSE in prostate cancer cells by measuring luciferase activity using a pGL3-PSA construct bearing the AR element in the human prostate cancer cell line LNCaP (P < .05). GSE treatment also decreased the mRNA level of the AR-regulated genes PSA and NKX 3.1. Finally, GSE inhibited growth of LNCaP cells. These results indicate that GSE potently inhibits HAT, leading to decreased AR-mediated transcription and cancer cell growth, and implicate GSE as a novel candidate for therapeutic activity against prostate cancer.

Modulation of histone H3 lysine 56 acetylation as an antifungal therapeutic strategy.

Candida albicans is a major fungal pathogen that causes serious systemic and mucosal infections in immunocompromised individuals. In yeast, histone H3 Lys56 acetylation (H3K56ac) is an abundant modification regulated by enzymes that have fungal-specific properties, making them appealing targets for antifungal therapy. Here we demonstrate that H3K56ac in C. albicans is regulated by the RTT109 and HST3 genes, which respectively encode the H3K56 acetyltransferase (Rtt109p) and deacetylase (Hst3p). We show that reduced levels of H3K56ac sensitize C. albicans to genotoxic and antifungal agents. Inhibition of Hst3p activity by conditional gene repression or nicotinamide treatment results in a loss of cell viability associated with abnormal filamentous growth, histone degradation and gross aberrations in DNA staining. We show that genetic or pharmacological alterations in H3K56ac levels reduce virulence in a mouse model of C. albicans infection. Our results demonstrate that modulation of H3K56ac is a unique strategy for treatment of C. albicans and, possibly, other fungal infections.