Abscisic acid （ABA） regulates diverse plant processes, growth and development under non-stress conditions and plays a pivotal role in abiotic stress tolerance. Although ABA-regulated genetic processes are well known...Abscisic acid （ABA） regulates diverse plant processes, growth and development under non-stress conditions and plays a pivotal role in abiotic stress tolerance. Although ABA-regulated genetic processes are well known, recent discoveries reveal that epigenetic processes are an integral part of ABA-regulated processes. Epigenetic mechanisms, namely, histone modifications and cytosine DNA methylation-induced modification of genome give rise to epigenomes, which add diversity and complexity to the genome of organisms. Histone monoubiquitination appears to regulate ABA levels in developing seeds through histone H2B monoubiquitination. ABA and H2B ubiquitination dependent chromatin remodeling regulate seed dormancy. Transcription factor networks necessary for seed maturation are repressed by histone deacetylases （HDACs）-dependent and PICKLE chromatin remodeling complexes （CRCs）, whereas ABA induces the expression of these genes directly or through repression of HDACs. Abiotic stress-induced ABA regulates stomatal response and stress- responsive gene expression through HDACs and HOS15-dependent histone deacetylation, as well as through the ATP- dependent SWITCH/SUCROSE NONFERMENTING CRC. ABA also probably regulates the abiotic stress response through DNA methylation and short interfering RNA pathways. Further studies on ABA-regulated epigenome will be of immense use to understand the plant development, stress adaptation and stress memory.展开更多
Reversible histone acetylation and deacetylation at the N-terminus of histone tails play crucial roles in regulation of eukaryotic gene activity. Acetylation of core histones usually induces an ＇open＇ chromatin stru...Reversible histone acetylation and deacetylation at the N-terminus of histone tails play crucial roles in regulation of eukaryotic gene activity. Acetylation of core histones usually induces an ＇open＇ chromatin structure and is associated with gene activation, whereas deacetylation of histone is often correlated with ＇closed＇ chromatin and gene repression. Histone deacetylation is catalyzed by histone deacetylases （HDACs）. A growing number of studies have demonstrated the importance of histone deacetylation/acetylation on genome stability, transcriptional regulation, and development in plants. Furthermore, HDACs were shown to interact with various chromatin remolding factors and transcription factors involved in transcriptional repression in multiple developmental processes. In this review, we summarized recent findings on the transcriptional repression mediated by HDACs in plants.展开更多
Lysine acetylation, one of the major types of post-translational modifications, plays critical roles in regulating gene expression and protein function. Histone deacetylases(HDACs) are responsible for removing acetyl ...Lysine acetylation, one of the major types of post-translational modifications, plays critical roles in regulating gene expression and protein function. Histone deacetylases(HDACs) are responsible for removing acetyl groups from lysines of both histone and non-histone proteins. While tremendous progress has been made in understanding the function and mechanism of HDACs in animals in the past two decades, nearly half of the HDAC studies in plants were reported within the past five years. In this review,we summarize the major findings on plant HDACs, with a focus on the model plant Arabidopsis thaliana, and highlight the components, regulatory mechanisms, and biological functions of HDAC complexes.展开更多
Pancreatic cancer is one of the most aggressive human cancers,with more than 200 000 deaths worldwide every year.Despite recent efforts,conventional treatment approaches,such as surgery and classic chemotherapy,have o...Pancreatic cancer is one of the most aggressive human cancers,with more than 200 000 deaths worldwide every year.Despite recent efforts,conventional treatment approaches,such as surgery and classic chemotherapy,have only slightly improved patient outcomes.More effective and well-tolerated therapies are required to reverse the current poor prognosis of this type of neoplasm.Among new agents,histone deacetylase inhibitors (HDACIs) are now being tested.HDACIs have multiple biological effects related to acetylation of histones and many non-histone proteins that are involved in regulation of gene expression,apoptosis,cell cycle progression and angiogenesis.HDACIs induce cell cycle arrest and can activate the extrinsic and intrinsic pathways of apoptosis in different cancer cell lines.In the present review,the main mechanisms by which HDACIs act in pancreatic cancer cells in vitro,as well as their antiproliferative effects in animal models are presented.HDACIs constitute a promising treatment for pancreatic cancer with encouraging anti-tumor ef-fects,at well-tolerated doses.展开更多
Epigenetic modifications include DNA methylation, his-tone modifications, and micro RNA. Gene alterations have been found to be associated with cardiovascular diseases, and epigenetic mechanisms are continuously being...Epigenetic modifications include DNA methylation, his-tone modifications, and micro RNA. Gene alterations have been found to be associated with cardiovascular diseases, and epigenetic mechanisms are continuously being studied to find new useful strategies for the clinical management of afflicted patients. Numerous cardiovascular disorders are characterized by the abnormal methylation of Cp G islands and so specific drugs that could inhibit DNA methyltransferase directly or by reducing its gene expression(e.g., hydralazine and procainamide) are currently under investigation. The anti-proliferative and anti-inflammatory properties of histone deacetylase inhibitors and their cardio-protective effects have been confirmed in preclinical studies. Furthermore, the regulation of the expression of micro RNA targets through pharmacological tools is still under development. Indeed, large controlled trials are required to establish whether current possible candidate antisense micro RNAs could offer better therapeutic benefits in clinical practice. Here, we updated therapeutic properties, side effects, and feasibility of eme-rging epigenetic-based strategies in cardiovascular diseases by highlighting specific problematic issues that still affect the development of large scale novel therapeutic protocols.展开更多
Histone acetylation is a critical process in the regulation of chromatin structure and gene expression.Histone deacetylases(HDACs)remove the acetyl group,leading to chromatin condensation and transcriptional repressio...Histone acetylation is a critical process in the regulation of chromatin structure and gene expression.Histone deacetylases(HDACs)remove the acetyl group,leading to chromatin condensation and transcriptional repression.HDAC inhibitors are considered a new class of anticancer agents and have been shown to alter gene transcription and exert antitumor effects.This paper describes our work on the structural determination and structure-activity relationship(SAR)optimization of tetrahydroisoquinoline compounds as HDAC inhibitors.These compounds were tested for their ability to inhibit HDAC 1,3,6 and for their ability to inhibit the proliferation of a panel of cancer cell lines.Among these,compound 82 showed the greatest inhibitory activity toward HDAC 1,3,6 and strongly inhibited growth of the cancer cell lines,with results clearly superior to those of the reference compound,vorinostat(SAHA).Compound 82 increased the acetylation of histones H3,H4 and tubulin in a concentration-dependent manner,suggesting that it is a broad inhibitor of HDACs.展开更多
Background:Cochlear hair cell injury is a common pathological feature of hearing loss.The basic helix-loop-helix family,member e40(Bhlhe40),a gene belonging to the basic helix-loop-helix(bHLH)family,exhibits strong tr...Background:Cochlear hair cell injury is a common pathological feature of hearing loss.The basic helix-loop-helix family,member e40(Bhlhe40),a gene belonging to the basic helix-loop-helix(bHLH)family,exhibits strong transcriptional repression activity.Methods:Oxidative damage,in House Ear Institute-Organ of Corti 1(HEI-OC1)cells,was caused using hydrogen peroxide(H2O2).The Ad-Bhlhe40 particles were constructed to overexpress Bhlhe40 in HEI-OC1 cells.Various assays including cell counting kit-8(CCK-8),terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay(TUNEL),flow cytometry,immunofluorescence,and corresponding commercial kits were employed to investigate the impacts of Bhlhe40 on cell viability,apoptosis,oxidative stress levels,mitochondrial membrane potential and cellular senescence.Additionally,a dual-luciferase reporter assay was performed to confirm the targeting of the histone deacetylases 2(Hdac2)by Bhlhe40.Results:The results revealed that Bhlhe40 was downregulated in H_(2)O_(2)-treated HEI-OC1 cells,but its overexpression improved cell viability and mitigated H_(2)O_(2)-induced oxidative injury in HEI-OC1 cells with increase of superoxide dismutase(SOD),catalase(CAT)and glutathione peroxidase(GPx)activities and decrease of reactive oxygen species(ROS)levels.Besides,overexpression of Bhlhe40 suppressed H_(2)O_(2)-triggered cell senescence,as evidenced by the fact that the upregulation of P53,P21,and P16 in HEI-OC1 cells treated with H2O2 were all alleviated by Bhlhe40 overexpression.And we further verified that overexpression of Bhlhe40 could inhibit the expression of Hdac2,which may be related to the repression of Hdac2 transcription.Conclusion:This study suggests that Bhlhe40 plays a protective role against senescence and oxidative damage in cochlear hair cells exposed to H2O2.展开更多
Head and neck squamous cell carcinoma(HNSCC) is the sixth most common cancer worldwide, and is responsible for a quarter of a million deaths annually. The survival rate for HNSCC patients is poor, showing only minor i...Head and neck squamous cell carcinoma(HNSCC) is the sixth most common cancer worldwide, and is responsible for a quarter of a million deaths annually. The survival rate for HNSCC patients is poor, showing only minor improvement in the last three decades. Despite new surgical techniques and chemotherapy protocols, tumor resistance to chemotherapy remains a significant challenge for HNSCC patients. Numerous mechanisms underlie chemoresistance, including genetic and epigenetic alterations in cancer cells that may be acquired during treatment and activation of mitogenic signaling pathways, such as nuclear factor kappa-light-chain-enhancer-of activated B cell, that cause reduced apoptosis. In addition to dysfunctional molecular signaling, emerging evidence reveals involvement of cancer stem cells(CSCs) in tumor development and in tumor resistance to chemotherapy and radiotherapy. These observations have sparked interest in understanding the mechanisms involved in the control of CSC function and fate. Post-translational modifications of histones dynamically influence gene expression independent of alterations to the DNA sequence. Recent findings from our group have shown that pharmacological induction of posttranslational modifications of tumor histones dynamically modulates CSC plasticity. These findings suggest that a better understanding of the biology of CSCs in response to epigenetic switches and pharmacological inhibitors of histone function may directly translate to the development of a mechanism-based strategy to disrupt CSCs. In this review, we present and discuss current knowledge on epigenetic modifications of HNSCC and CSC response to DNA methylation and histone modifications. In addition, we discuss chromatin modifications and their role in tumor resistance to therapy.展开更多
Hepatocellular carcinoma(HCC)is one of the most commonly diagnosed cancers and a leading cause of cancerrelated mortality worldwide,but its pathogenesis remains largely unknown.Nevertheless,genomic instability has bee...Hepatocellular carcinoma(HCC)is one of the most commonly diagnosed cancers and a leading cause of cancerrelated mortality worldwide,but its pathogenesis remains largely unknown.Nevertheless,genomic instability has been recognized as one of the facilitating characteristics of cancer hallmarks that expedites the acquisition of genetic diversity.Genomic instability is associated with a greater tendency to accumulate DNA damage and tumor-specific DNA repair defects,which gives rise to gene mutations and chromosomal damage and causes oncogenic transformation and tumor progression.Histone deacetylases(HDACs)have been shown to impair a variety of cellular processes of genome stability,including the regulation of DNA damage and repair,reactive oxygen species generation and elimination,and progression to mitosis.In this review,we provide an overview of the role of HDAC in the different aspects of DNA repair and genome instability in HCC as well as the current progress on the development of HDAC-specific inhibitors as new cancer therapies.展开更多
Pancreatic cancer,although not very frequent,has an exceptionally high mortality rate,making it one of the most common causes of cancer mortality in developed countries.Pancreatic cancer is difficult to diagnose,allow...Pancreatic cancer,although not very frequent,has an exceptionally high mortality rate,making it one of the most common causes of cancer mortality in developed countries.Pancreatic cancer is difficult to diagnose,allowing few patients to have the necessary treatment at a relatively early stage.Despite a marginal benefit in survival,the overall response of pancreatic cancer to current systemic therapy continues to be poor,and new therapies are desperately needed.Histone deacetylase(HDAC) enzymes play an important role in the development and progression of cancer and HDAC inhibitors(HDACIs) have been shown to induce differentiation and cell cycle arrest,activate the extrinsic or intrinsic pathways of apoptosis,and inhibit invasion,migration and angiogenesis in different cancer cell lines.As a result of promising preclinical data,various HDACIs are being tested as either monotherapeutic agents or in combination regimens for both solid and hematological malignancies.Vorinostat was the first HDACI approved by the Food and Drug Administration for patients with cutaneous T-cell lymphoma.The use of HDACIs in clinical trials,in pretreated and relapsed patients suffering from advanced pancreatic cancer is discussed.Unfortunately,clinical data for HDACIs in patients with pancreatic cancer are inadequate,because only a few studies have included patients suffering from this type of neoplasm and the number of pancreatic cancer patients that entered HDACIs phase Ⅱ/Ⅲ trials,among others with advanced solid tumors,is very limited.More studies recruiting patients with pancreatic cancer remain to determine the efficiency of these therapies.展开更多
Epigenetic mechanisms such as DNA methylation,histone modification and microRNA changes have been shown to be important for the regulation of cellular functions.Among them,histone deacetylases(HDACs)are enzymes that b...Epigenetic mechanisms such as DNA methylation,histone modification and microRNA changes have been shown to be important for the regulation of cellular functions.Among them,histone deacetylases(HDACs)are enzymes that balance the acetylation activities of histone acetyltransferases in chromatin remodeling and play essential roles in gene transcription to regulate cell proliferation,migration and death.Recent studies indicate that HDACs are promising drug targets for a wide range of diseases including cancer,neurodegenerative and psychiatric disorders,cardiovascular dysfunction,autoimmunity and diabetes mellitus.This review highlights the role of HDACs in diabetes mellitus and outlines several important cellular and molecular mechanisms by which HDACs regulate glucose homeostasis and can be targeted for the treatment of dia betic microvascular complications.It is hoped that our understanding of the role of HDACs in diabetes.mellitus will lead to the development of better diagnostic tools and the design of more potent and specific drugs targeting selective HDAC proteins for the treatment of the disease.展开更多
The HIV-1 LTR controls the expression of HIV-1 viral genes and thus is critical for viral propagation and pathology. Numerous host factors have been shown to participate in the regulation of the LTR promoter. Among th...The HIV-1 LTR controls the expression of HIV-1 viral genes and thus is critical for viral propagation and pathology. Numerous host factors have been shown to participate in the regulation of the LTR promoter. Among them is the thyroid hormone (T3) receptor (TR). TR has been shown to bind to the critical region of the promoter that contain the NFbB and Sp1 binding sites. Interestingly, earlier transient transfection studies in tissue culture cells have yielded contradicting conclusions on the role of TR in LTR regulation, likely due to the use of different cell types and/or lack of proper chromatin organization. Here, using the frog oocyte as a model system that allows replication-coupled chromatin assembly, mimicking that in somatic cells, we demonstrate that unliganded heterodimers of TR and RXR (9-cis retinoic acid receptor) repress LTR while the addition of T3 relieves the repression and further activates the promoter. More importantly, we show that chromatin and unliganded TR/RXR synergize to repress the promoter in a histone deacetylase-dependent manner.展开更多
Background： Placental multidrug resistance-associated protein 2 （MRP2）, encoded by ABCC2 gene in human, plays a significant role in regulating drugs＇ transplacental transfer rates. Studies o11 placental MRP2 regul...Background： Placental multidrug resistance-associated protein 2 （MRP2）, encoded by ABCC2 gene in human, plays a significant role in regulating drugs＇ transplacental transfer rates. Studies o11 placental MRP2 regulation could provide more therapeutic targets for individualized and safe pharmacotherapy during pregnancy. Currently, the roles of epigenetic mechanisms in regulating placental drug transporters are still unclear. This study aimed to investigate the effect of histone deacetylases （HDACs） inhibition on MRP2 expression in the placental trophoblast cell line and to explore whether HDAC 1/2/3 are preliminarily involved in this process. Methods： The human choriocarcinoma-derived trophoblast cell line （Bewo cells） was treated with the HDAC inhibitors-trichostatin A （TSA） at different concentration gradients of 0.5, 1.0, 3.0, and 5.0 μmol/L. Cells were harvested after 24 and 48 h treatment. Small interfering RNA （siRNA） specific for HDACI/HDAC2/HDAC3 or control siRNA was transfected into cells. Total HDAC activity was detected by colorimetric assay kits. HDAC 1/2/3/ABCC2 messenger RNA （mRNA） and protein expressions were determined by real-time quantitative polymerase chain reaction and Western-blot analysis, respectively. Immunofluorescence for MRP2 protein expression was visualized and assessed using an immunofluorescence microscopy and ImageJ software, respectively. Results： TSA could inhibit total HDAC activity and HDAC 1/2/3 expression in company with increase ofM RP2 expression in Bewo cells. Reduction of HDAC 1 protein level was noted after 24 h of TSA incubation at 1.0, 3.0, and 5.0 μmol/L （vs. vehicle group, all P 〈 0.001 ）, accompanied with dose-dependent induction of MRP2 expression （P = 0.045 for 1.0 μmol/L, P = 0.001 for 3.0 μmol/L, and P 〈 0.001 for 5.0 μmol/L）, whereas no significant diferences in MRP2 expression were noted after HDAC2/3 silencing. Fluorescent micrograph images of MRP2 protein were expressed on the cell membrane. The fluorescent int展开更多
Cardiovascular diseases(CVDs), which include alldiseases of the heart and circulation system, are the leading cause of deaths on the globally. During the development of CVDs, choric inflammatory, lipid metabolism diso...Cardiovascular diseases(CVDs), which include alldiseases of the heart and circulation system, are the leading cause of deaths on the globally. During the development of CVDs, choric inflammatory, lipid metabolism disorder and endothelial dysfunction are widely recognized risk factors. Recently, the new treatment for CVDs that designed to regenerate the damaged myocardium and injured vascular endothelium and improve recovery by the use of stem cells, attracts more and more public attention. Histone deacetylases(HDACs) are a family of enzymes that remove acetyl groups from lysine residues of histone proteins allowing the histones to wrap the DNA more tightly and commonly known as epigenetic regulators of gene transcription. HDACs play indispensable roles in nearly all biological processes, such as transcriptional regulation, cell cycle progression and developmental events, and have originally shown to be involved in cancer and neurological diseases. HDACs are also found to play crucial roles in cardiovascular diseases by modulating vascular cell homeostasis(e.g., proliferation, migration, and apoptosis of both ECs and SMCs). This review focuses on the roles of different members of HDACs and HDAC inhibitor on stem cell/ progenitor cell differentiation toward vascular cell lineages(endothelial cells, smooth muscle cells and Cardiomyocytes) and its potential therapeutics.展开更多
Because pancreatic cancer(PC) historically has had poor prognosis and five year survival rates,it has been intensely investigated.Analysis of PC incidence and biology has shown a link between different risk factors su...Because pancreatic cancer(PC) historically has had poor prognosis and five year survival rates,it has been intensely investigated.Analysis of PC incidence and biology has shown a link between different risk factors such as smoking,alcoholism,and obesity and disease progression.Important factors affecting PC include the epigenomic changes driven by DNA methylation and histone acetylation,and actions of microRNA inducing oncogenic or tumor suppressor effects.Studies have identified markers whose dysregulation seem to play important roles in PC progression.PC markers involve classical histone deacetylases(HDAC),PC stem cell(PCSC),and leptin.In this review,we discuss the role of several PC biomarkers,and the potential crosstalk between HDAC,microRNA,and leptin in PC progression.Dysregulated expression of these molecules can increase proliferation,survival,PCSC,resistance to chemotherapy and tumor angiogenesis.The potential relationships between these molecules are further analyzed using data from The Cancer Genome Atlas and crosstalk pathways generated by the Pathway Studio Platform(Ariadne Genomics,Inc.).Oncogenic miRNA21 and tumor suppressor miRNA200 have been previously linked to leptin signaling.Preliminary analysis of PC biopsies and signaling crosstalk suggests that the main adipokine leptin could affect the expression of microRNA and HDAC in PC.Data analysis suggests that HDAC-microRNA-leptin signaling crosstalk may be a new target for PC therapy.展开更多
Globally,hepatocellular carcinoma(HCC)is a leading cause of cancer and cancerrelated deaths.The therapeutic efficacy of locoregional and systemic treatment in patients with advanced HCC remains low,which results in a ...Globally,hepatocellular carcinoma(HCC)is a leading cause of cancer and cancerrelated deaths.The therapeutic efficacy of locoregional and systemic treatment in patients with advanced HCC remains low,which results in a poor prognosis.The development of sorafenib for the treatment of HCC has resulted in a new era of molecular targeted therapy for this disease.However,the median overall survival was reported to be barely higher in the sorafenib treatment group than in the control group.Hence,in this review we describe the importance of developing more effective targeted therapies for the management of advanced HCC.Recent investigations of molecular signaling pathways in several cancers have provided some insights into developing molecular therapies that target critical members of these signaling pathways.Proteins involved in the Hedgehog and Notch signaling pathways,Polo-like kinase 1,arginine,histone deacetylases and Glypican-3 can be potential targets in the treatment of HCC.Monotherapy has limited therapeutic efficacy due to the development of inhibitory feedback mechanisms and induction of chemoresistance.Thus,emphasis is now on the development of personalized and combination molecular targeted therapies that can serve as ideal therapeutic strategies for improved management of HCC.展开更多
Although the clinical manifestations of alcoholic liver disease are well-described, little is known about the molecular basis of liver injury. Recent studies have indicated that ethanol exposure induces global protein...Although the clinical manifestations of alcoholic liver disease are well-described, little is known about the molecular basis of liver injury. Recent studies have indicated that ethanol exposure induces global protein hyperacetylationo This reversible, post- translational modification on the E-amino groups of lysine residues has been shown to modulate multiple, diverse cellular processes ranging from transcriptional activation to microtubule stability. Thus, alcohol- induced protein hyperacetylation likely leads to major physiological consequences that contribute to alcohol-induced hepatotoxicity. Lysine acetylation is controlled by the activities of two opposing enzymes, histone acetyltransferases and histone deacetylases. Currently, efforts are aimed at determining which enzymes are responsible for the increased acetylation of specific substrates. However, the greater challenge will be to determine the physiological ramifications of protein hyperacetylation and how they might contribute to the progression of liver disease. In this review, we will first list and discuss the proteins known to be hyperacetylated in the presence of ethanol. We will then describe what is known about the mechanisms leading to increased protein acetylation and how hyperacetylation may perturb hepatic function.展开更多
Sirtuins(SIRTs) are NAD+-dependent histone deacetylases and play a role in virtually all cell biological processes. As SIRTs functions vary according to their subtypes, they can either activate or inhibit signaling pa...Sirtuins(SIRTs) are NAD+-dependent histone deacetylases and play a role in virtually all cell biological processes. As SIRTs functions vary according to their subtypes, they can either activate or inhibit signaling pathways upon different conditions or tissues. Recent studies have focused on metabolic effects performed by SIRTs in several cell types since specific metabolic pathways(e.g., aerobic glycolysis, oxidative phosphorylation, β-oxidation, glutaminolysis) are used to determine the cell fate. However, few efforts have been made to understand the role of SIRTs on B lymphocytes metabolism and function. These cells are associated with humoral immune responses by secreting larger amounts of antibodies after differentiating into antibody-secreting cells. Besides, both the SIRTs and B lymphocytes are potential targets to treat several immune-mediated disorders, including cancer. Here, we provide an outlook of recent studies regarding the role of SIRTs in general cellular metabolism and B lymphocytes functions, pointing out the future perspectives of this field.展开更多
The increasing incidence of obesity worldwide and its related cardiometabolic complications is an urgent public health problem. While weight gain results from a negative balance between the energy expenditure and calo...The increasing incidence of obesity worldwide and its related cardiometabolic complications is an urgent public health problem. While weight gain results from a negative balance between the energy expenditure and calorie intake, recent research has demonstrated that several small organic molecules containing a four-carbon backbone can modulate this balance by favoring energy expenditure, and alleviating endoplasmic reticulum stress and oxidative stress. Such small molecules include the bacterially produced short chain fatty acid butyric acid, its chemically produced derivative 4-phenylbutyric acid, the main ketone body D-β-hydroxybutyrate- synthesized by the liver- and the recently discovered myokine β-aminoisobutyric acid. Conversely, another butyraterelated molecule, α-hydroxybutyrate, has been found to be an early predictor of insulin resistance and glucose intolerance. In this minireview, we summarize recent advances in the understanding of the mechanism of action of these molecules, and discuss their use as therapeutics to improve metabolic homeostasis or their detection as early biomarkers of incipient insulin resistance.展开更多
基金SERC Fact Track Scheme for Young Scientist, DST, Govt.of India, New Delhi to V. Chinnusamythe State Key Basic Researchand Development Plan of China (2003CB114300)the National Natural Science Foundation of China (30421002 and 30670182) to Z. Gong.
文摘Abscisic acid （ABA） regulates diverse plant processes, growth and development under non-stress conditions and plays a pivotal role in abiotic stress tolerance. Although ABA-regulated genetic processes are well known, recent discoveries reveal that epigenetic processes are an integral part of ABA-regulated processes. Epigenetic mechanisms, namely, histone modifications and cytosine DNA methylation-induced modification of genome give rise to epigenomes, which add diversity and complexity to the genome of organisms. Histone monoubiquitination appears to regulate ABA levels in developing seeds through histone H2B monoubiquitination. ABA and H2B ubiquitination dependent chromatin remodeling regulate seed dormancy. Transcription factor networks necessary for seed maturation are repressed by histone deacetylases （HDACs）-dependent and PICKLE chromatin remodeling complexes （CRCs）, whereas ABA induces the expression of these genes directly or through repression of HDACs. Abiotic stress-induced ABA regulates stomatal response and stress- responsive gene expression through HDACs and HOS15-dependent histone deacetylation, as well as through the ATP- dependent SWITCH/SUCROSE NONFERMENTING CRC. ABA also probably regulates the abiotic stress response through DNA methylation and short interfering RNA pathways. Further studies on ABA-regulated epigenome will be of immense use to understand the plant development, stress adaptation and stress memory.
文摘Reversible histone acetylation and deacetylation at the N-terminus of histone tails play crucial roles in regulation of eukaryotic gene activity. Acetylation of core histones usually induces an ＇open＇ chromatin structure and is associated with gene activation, whereas deacetylation of histone is often correlated with ＇closed＇ chromatin and gene repression. Histone deacetylation is catalyzed by histone deacetylases （HDACs）. A growing number of studies have demonstrated the importance of histone deacetylation/acetylation on genome stability, transcriptional regulation, and development in plants. Furthermore, HDACs were shown to interact with various chromatin remolding factors and transcription factors involved in transcriptional repression in multiple developmental processes. In this review, we summarized recent findings on the transcriptional repression mediated by HDACs in plants.
文摘Lysine acetylation, one of the major types of post-translational modifications, plays critical roles in regulating gene expression and protein function. Histone deacetylases(HDACs) are responsible for removing acetyl groups from lysines of both histone and non-histone proteins. While tremendous progress has been made in understanding the function and mechanism of HDACs in animals in the past two decades, nearly half of the HDAC studies in plants were reported within the past five years. In this review,we summarize the major findings on plant HDACs, with a focus on the model plant Arabidopsis thaliana, and highlight the components, regulatory mechanisms, and biological functions of HDAC complexes.
文摘Pancreatic cancer is one of the most aggressive human cancers,with more than 200 000 deaths worldwide every year.Despite recent efforts,conventional treatment approaches,such as surgery and classic chemotherapy,have only slightly improved patient outcomes.More effective and well-tolerated therapies are required to reverse the current poor prognosis of this type of neoplasm.Among new agents,histone deacetylase inhibitors (HDACIs) are now being tested.HDACIs have multiple biological effects related to acetylation of histones and many non-histone proteins that are involved in regulation of gene expression,apoptosis,cell cycle progression and angiogenesis.HDACIs induce cell cycle arrest and can activate the extrinsic and intrinsic pathways of apoptosis in different cancer cell lines.In the present review,the main mechanisms by which HDACIs act in pancreatic cancer cells in vitro,as well as their antiproliferative effects in animal models are presented.HDACIs constitute a promising treatment for pancreatic cancer with encouraging anti-tumor ef-fects,at well-tolerated doses.
文摘Epigenetic modifications include DNA methylation, his-tone modifications, and micro RNA. Gene alterations have been found to be associated with cardiovascular diseases, and epigenetic mechanisms are continuously being studied to find new useful strategies for the clinical management of afflicted patients. Numerous cardiovascular disorders are characterized by the abnormal methylation of Cp G islands and so specific drugs that could inhibit DNA methyltransferase directly or by reducing its gene expression(e.g., hydralazine and procainamide) are currently under investigation. The anti-proliferative and anti-inflammatory properties of histone deacetylase inhibitors and their cardio-protective effects have been confirmed in preclinical studies. Furthermore, the regulation of the expression of micro RNA targets through pharmacological tools is still under development. Indeed, large controlled trials are required to establish whether current possible candidate antisense micro RNAs could offer better therapeutic benefits in clinical practice. Here, we updated therapeutic properties, side effects, and feasibility of eme-rging epigenetic-based strategies in cardiovascular diseases by highlighting specific problematic issues that still affect the development of large scale novel therapeutic protocols.
基金supported financially by the National Science & Technology Major Project ‘Key New Drug Creation and Manufacturing Program’ of China(Grant No.2014ZX09507002)the National Marine ‘863’ Project(No.2013AA092902)
文摘Histone acetylation is a critical process in the regulation of chromatin structure and gene expression.Histone deacetylases(HDACs)remove the acetyl group,leading to chromatin condensation and transcriptional repression.HDAC inhibitors are considered a new class of anticancer agents and have been shown to alter gene transcription and exert antitumor effects.This paper describes our work on the structural determination and structure-activity relationship(SAR)optimization of tetrahydroisoquinoline compounds as HDAC inhibitors.These compounds were tested for their ability to inhibit HDAC 1,3,6 and for their ability to inhibit the proliferation of a panel of cancer cell lines.Among these,compound 82 showed the greatest inhibitory activity toward HDAC 1,3,6 and strongly inhibited growth of the cancer cell lines,with results clearly superior to those of the reference compound,vorinostat(SAHA).Compound 82 increased the acetylation of histones H3,H4 and tubulin in a concentration-dependent manner,suggesting that it is a broad inhibitor of HDACs.
基金This research was supported by the Special Fund for Economic and Technological Development of Longgang District,Shenzhen(LGKCYLWS2021000030).
文摘Background:Cochlear hair cell injury is a common pathological feature of hearing loss.The basic helix-loop-helix family,member e40(Bhlhe40),a gene belonging to the basic helix-loop-helix(bHLH)family,exhibits strong transcriptional repression activity.Methods:Oxidative damage,in House Ear Institute-Organ of Corti 1(HEI-OC1)cells,was caused using hydrogen peroxide(H2O2).The Ad-Bhlhe40 particles were constructed to overexpress Bhlhe40 in HEI-OC1 cells.Various assays including cell counting kit-8(CCK-8),terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay(TUNEL),flow cytometry,immunofluorescence,and corresponding commercial kits were employed to investigate the impacts of Bhlhe40 on cell viability,apoptosis,oxidative stress levels,mitochondrial membrane potential and cellular senescence.Additionally,a dual-luciferase reporter assay was performed to confirm the targeting of the histone deacetylases 2(Hdac2)by Bhlhe40.Results:The results revealed that Bhlhe40 was downregulated in H_(2)O_(2)-treated HEI-OC1 cells,but its overexpression improved cell viability and mitigated H_(2)O_(2)-induced oxidative injury in HEI-OC1 cells with increase of superoxide dismutase(SOD),catalase(CAT)and glutathione peroxidase(GPx)activities and decrease of reactive oxygen species(ROS)levels.Besides,overexpression of Bhlhe40 suppressed H_(2)O_(2)-triggered cell senescence,as evidenced by the fact that the upregulation of P53,P21,and P16 in HEI-OC1 cells treated with H2O2 were all alleviated by Bhlhe40 overexpression.And we further verified that overexpression of Bhlhe40 could inhibit the expression of Hdac2,which may be related to the repression of Hdac2 transcription.Conclusion:This study suggests that Bhlhe40 plays a protective role against senescence and oxidative damage in cochlear hair cells exposed to H2O2.
基金Supported by University of Michigan,School of Dentistry startup
文摘Head and neck squamous cell carcinoma(HNSCC) is the sixth most common cancer worldwide, and is responsible for a quarter of a million deaths annually. The survival rate for HNSCC patients is poor, showing only minor improvement in the last three decades. Despite new surgical techniques and chemotherapy protocols, tumor resistance to chemotherapy remains a significant challenge for HNSCC patients. Numerous mechanisms underlie chemoresistance, including genetic and epigenetic alterations in cancer cells that may be acquired during treatment and activation of mitogenic signaling pathways, such as nuclear factor kappa-light-chain-enhancer-of activated B cell, that cause reduced apoptosis. In addition to dysfunctional molecular signaling, emerging evidence reveals involvement of cancer stem cells(CSCs) in tumor development and in tumor resistance to chemotherapy and radiotherapy. These observations have sparked interest in understanding the mechanisms involved in the control of CSC function and fate. Post-translational modifications of histones dynamically influence gene expression independent of alterations to the DNA sequence. Recent findings from our group have shown that pharmacological induction of posttranslational modifications of tumor histones dynamically modulates CSC plasticity. These findings suggest that a better understanding of the biology of CSCs in response to epigenetic switches and pharmacological inhibitors of histone function may directly translate to the development of a mechanism-based strategy to disrupt CSCs. In this review, we present and discuss current knowledge on epigenetic modifications of HNSCC and CSC response to DNA methylation and histone modifications. In addition, we discuss chromatin modifications and their role in tumor resistance to therapy.
基金supported by grants from the Science and Technology Research Program of Chongqing Education Commission (no.KJQN202100424)the Natural Science Foundation Project of Chongqing (no.cstc2018jcyjAX0825).
文摘Hepatocellular carcinoma(HCC)is one of the most commonly diagnosed cancers and a leading cause of cancerrelated mortality worldwide,but its pathogenesis remains largely unknown.Nevertheless,genomic instability has been recognized as one of the facilitating characteristics of cancer hallmarks that expedites the acquisition of genetic diversity.Genomic instability is associated with a greater tendency to accumulate DNA damage and tumor-specific DNA repair defects,which gives rise to gene mutations and chromosomal damage and causes oncogenic transformation and tumor progression.Histone deacetylases(HDACs)have been shown to impair a variety of cellular processes of genome stability,including the regulation of DNA damage and repair,reactive oxygen species generation and elimination,and progression to mitosis.In this review,we provide an overview of the role of HDAC in the different aspects of DNA repair and genome instability in HCC as well as the current progress on the development of HDAC-specific inhibitors as new cancer therapies.
文摘Pancreatic cancer,although not very frequent,has an exceptionally high mortality rate,making it one of the most common causes of cancer mortality in developed countries.Pancreatic cancer is difficult to diagnose,allowing few patients to have the necessary treatment at a relatively early stage.Despite a marginal benefit in survival,the overall response of pancreatic cancer to current systemic therapy continues to be poor,and new therapies are desperately needed.Histone deacetylase(HDAC) enzymes play an important role in the development and progression of cancer and HDAC inhibitors(HDACIs) have been shown to induce differentiation and cell cycle arrest,activate the extrinsic or intrinsic pathways of apoptosis,and inhibit invasion,migration and angiogenesis in different cancer cell lines.As a result of promising preclinical data,various HDACIs are being tested as either monotherapeutic agents or in combination regimens for both solid and hematological malignancies.Vorinostat was the first HDACI approved by the Food and Drug Administration for patients with cutaneous T-cell lymphoma.The use of HDACIs in clinical trials,in pretreated and relapsed patients suffering from advanced pancreatic cancer is discussed.Unfortunately,clinical data for HDACIs in patients with pancreatic cancer are inadequate,because only a few studies have included patients suffering from this type of neoplasm and the number of pancreatic cancer patients that entered HDACIs phase Ⅱ/Ⅲ trials,among others with advanced solid tumors,is very limited.More studies recruiting patients with pancreatic cancer remain to determine the efficiency of these therapies.
基金The authors wish to thank the following for financial support for this study:the National 973 Basic Research Program of China(2012CB517700)the National Nature Science Foundation of China(81170772,81070918,81171062 and 30901551)+2 种基金the Shandong Natural Science Fund for Distin-guished Young Scholars to Yi F(JQ201121)the Independent Innovation Foundation of Shandong University(IIFS-DU2010JC17)the Nature Science Foundation of Shan-dong Province(ZR2010HM112).
文摘Epigenetic mechanisms such as DNA methylation,histone modification and microRNA changes have been shown to be important for the regulation of cellular functions.Among them,histone deacetylases(HDACs)are enzymes that balance the acetylation activities of histone acetyltransferases in chromatin remodeling and play essential roles in gene transcription to regulate cell proliferation,migration and death.Recent studies indicate that HDACs are promising drug targets for a wide range of diseases including cancer,neurodegenerative and psychiatric disorders,cardiovascular dysfunction,autoimmunity and diabetes mellitus.This review highlights the role of HDACs in diabetes mellitus and outlines several important cellular and molecular mechanisms by which HDACs regulate glucose homeostasis and can be targeted for the treatment of dia betic microvascular complications.It is hoped that our understanding of the role of HDACs in diabetes.mellitus will lead to the development of better diagnostic tools and the design of more potent and specific drugs targeting selective HDAC proteins for the treatment of the disease.
文摘The HIV-1 LTR controls the expression of HIV-1 viral genes and thus is critical for viral propagation and pathology. Numerous host factors have been shown to participate in the regulation of the LTR promoter. Among them is the thyroid hormone (T3) receptor (TR). TR has been shown to bind to the critical region of the promoter that contain the NFbB and Sp1 binding sites. Interestingly, earlier transient transfection studies in tissue culture cells have yielded contradicting conclusions on the role of TR in LTR regulation, likely due to the use of different cell types and/or lack of proper chromatin organization. Here, using the frog oocyte as a model system that allows replication-coupled chromatin assembly, mimicking that in somatic cells, we demonstrate that unliganded heterodimers of TR and RXR (9-cis retinoic acid receptor) repress LTR while the addition of T3 relieves the repression and further activates the promoter. More importantly, we show that chromatin and unliganded TR/RXR synergize to repress the promoter in a histone deacetylase-dependent manner.
文摘Background： Placental multidrug resistance-associated protein 2 （MRP2）, encoded by ABCC2 gene in human, plays a significant role in regulating drugs＇ transplacental transfer rates. Studies o11 placental MRP2 regulation could provide more therapeutic targets for individualized and safe pharmacotherapy during pregnancy. Currently, the roles of epigenetic mechanisms in regulating placental drug transporters are still unclear. This study aimed to investigate the effect of histone deacetylases （HDACs） inhibition on MRP2 expression in the placental trophoblast cell line and to explore whether HDAC 1/2/3 are preliminarily involved in this process. Methods： The human choriocarcinoma-derived trophoblast cell line （Bewo cells） was treated with the HDAC inhibitors-trichostatin A （TSA） at different concentration gradients of 0.5, 1.0, 3.0, and 5.0 μmol/L. Cells were harvested after 24 and 48 h treatment. Small interfering RNA （siRNA） specific for HDACI/HDAC2/HDAC3 or control siRNA was transfected into cells. Total HDAC activity was detected by colorimetric assay kits. HDAC 1/2/3/ABCC2 messenger RNA （mRNA） and protein expressions were determined by real-time quantitative polymerase chain reaction and Western-blot analysis, respectively. Immunofluorescence for MRP2 protein expression was visualized and assessed using an immunofluorescence microscopy and ImageJ software, respectively. Results： TSA could inhibit total HDAC activity and HDAC 1/2/3 expression in company with increase ofM RP2 expression in Bewo cells. Reduction of HDAC 1 protein level was noted after 24 h of TSA incubation at 1.0, 3.0, and 5.0 μmol/L （vs. vehicle group, all P 〈 0.001 ）, accompanied with dose-dependent induction of MRP2 expression （P = 0.045 for 1.0 μmol/L, P = 0.001 for 3.0 μmol/L, and P 〈 0.001 for 5.0 μmol/L）, whereas no significant diferences in MRP2 expression were noted after HDAC2/3 silencing. Fluorescent micrograph images of MRP2 protein were expressed on the cell membrane. The fluorescent int
基金Supported by British Heart Foundation project,No.PG13-63-30419
文摘Cardiovascular diseases(CVDs), which include alldiseases of the heart and circulation system, are the leading cause of deaths on the globally. During the development of CVDs, choric inflammatory, lipid metabolism disorder and endothelial dysfunction are widely recognized risk factors. Recently, the new treatment for CVDs that designed to regenerate the damaged myocardium and injured vascular endothelium and improve recovery by the use of stem cells, attracts more and more public attention. Histone deacetylases(HDACs) are a family of enzymes that remove acetyl groups from lysine residues of histone proteins allowing the histones to wrap the DNA more tightly and commonly known as epigenetic regulators of gene transcription. HDACs play indispensable roles in nearly all biological processes, such as transcriptional regulation, cell cycle progression and developmental events, and have originally shown to be involved in cancer and neurological diseases. HDACs are also found to play crucial roles in cardiovascular diseases by modulating vascular cell homeostasis(e.g., proliferation, migration, and apoptosis of both ECs and SMCs). This review focuses on the roles of different members of HDACs and HDAC inhibitor on stem cell/ progenitor cell differentiation toward vascular cell lineages(endothelial cells, smooth muscle cells and Cardiomyocytes) and its potential therapeutics.
基金Supported by NIH/NCI,No.1R41CA183399-01A1Department of Defense(DoD) office of the Congressionally Directed Medical Research Programs(CDMRP),No.DODXWH-13-1-0382+7 种基金the DOD W81XWH-13-1-0382NIH/SBIR1R41CA183399-01A1Pilot Project Award from MSM/Tuskegee University/UAB Cancer Center Partnership grant 5U54CA118638PC SPORE Grant from UAB to RRGPNational Institute on Minority Health and Health Disparities(NIMHD)of NIH under award number 5S21MD00101facilities and support services at MSM(1G12RR026250-03NIH RR 03034 and 1C06 RR18386)The Calvin Johnson Jr.Foundation Pancreatic Cancer Research Scholarship to Cynthia I Tchio Mantho
文摘Because pancreatic cancer(PC) historically has had poor prognosis and five year survival rates,it has been intensely investigated.Analysis of PC incidence and biology has shown a link between different risk factors such as smoking,alcoholism,and obesity and disease progression.Important factors affecting PC include the epigenomic changes driven by DNA methylation and histone acetylation,and actions of microRNA inducing oncogenic or tumor suppressor effects.Studies have identified markers whose dysregulation seem to play important roles in PC progression.PC markers involve classical histone deacetylases(HDAC),PC stem cell(PCSC),and leptin.In this review,we discuss the role of several PC biomarkers,and the potential crosstalk between HDAC,microRNA,and leptin in PC progression.Dysregulated expression of these molecules can increase proliferation,survival,PCSC,resistance to chemotherapy and tumor angiogenesis.The potential relationships between these molecules are further analyzed using data from The Cancer Genome Atlas and crosstalk pathways generated by the Pathway Studio Platform(Ariadne Genomics,Inc.).Oncogenic miRNA21 and tumor suppressor miRNA200 have been previously linked to leptin signaling.Preliminary analysis of PC biopsies and signaling crosstalk suggests that the main adipokine leptin could affect the expression of microRNA and HDAC in PC.Data analysis suggests that HDAC-microRNA-leptin signaling crosstalk may be a new target for PC therapy.
文摘Globally,hepatocellular carcinoma(HCC)is a leading cause of cancer and cancerrelated deaths.The therapeutic efficacy of locoregional and systemic treatment in patients with advanced HCC remains low,which results in a poor prognosis.The development of sorafenib for the treatment of HCC has resulted in a new era of molecular targeted therapy for this disease.However,the median overall survival was reported to be barely higher in the sorafenib treatment group than in the control group.Hence,in this review we describe the importance of developing more effective targeted therapies for the management of advanced HCC.Recent investigations of molecular signaling pathways in several cancers have provided some insights into developing molecular therapies that target critical members of these signaling pathways.Proteins involved in the Hedgehog and Notch signaling pathways,Polo-like kinase 1,arginine,histone deacetylases and Glypican-3 can be potential targets in the treatment of HCC.Monotherapy has limited therapeutic efficacy due to the development of inhibitory feedback mechanisms and induction of chemoresistance.Thus,emphasis is now on the development of personalized and combination molecular targeted therapies that can serve as ideal therapeutic strategies for improved management of HCC.
基金supported by the National Natural Science Foundation of China (No. 81260196, 81450036)the Natural Science Foundation of Inner Mongolia Autonomous Region (IMAR)(No. 2020MS08175, 2021MS08131, 2021LHMS08024)+3 种基金Science Foundation of Universities of IMAR (No. NJZY19218)Program for Young Talents of Science and Technology in Universities of IMAR (No. NJYT-17-B23)Science Foundation of Aerospace Medical Health Technology (AMHT)(No. 2020YK02, 2021YK05)Science Foundation of Aerospace Center Hospital (ASCH)(No. YN202104)。
基金Supported by The National Institute of Alcohol Abuse and Alcoholism (R21 AA015683) awarded to P.L.T.
文摘Although the clinical manifestations of alcoholic liver disease are well-described, little is known about the molecular basis of liver injury. Recent studies have indicated that ethanol exposure induces global protein hyperacetylationo This reversible, post- translational modification on the E-amino groups of lysine residues has been shown to modulate multiple, diverse cellular processes ranging from transcriptional activation to microtubule stability. Thus, alcohol- induced protein hyperacetylation likely leads to major physiological consequences that contribute to alcohol-induced hepatotoxicity. Lysine acetylation is controlled by the activities of two opposing enzymes, histone acetyltransferases and histone deacetylases. Currently, efforts are aimed at determining which enzymes are responsible for the increased acetylation of specific substrates. However, the greater challenge will be to determine the physiological ramifications of protein hyperacetylation and how they might contribute to the progression of liver disease. In this review, we will first list and discuss the proteins known to be hyperacetylated in the presence of ethanol. We will then describe what is known about the mechanisms leading to increased protein acetylation and how hyperacetylation may perturb hepatic function.
基金Supported by Fundacao de AmparoàPesquisa de Sao Paulo(FAPESP)under Agreements,No.2015/26682-6,No.2017/03248-4and No.2017/05264-7financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nível Superior–Brasil(CAPES)–Finance Code 001
文摘Sirtuins(SIRTs) are NAD+-dependent histone deacetylases and play a role in virtually all cell biological processes. As SIRTs functions vary according to their subtypes, they can either activate or inhibit signaling pathways upon different conditions or tissues. Recent studies have focused on metabolic effects performed by SIRTs in several cell types since specific metabolic pathways(e.g., aerobic glycolysis, oxidative phosphorylation, β-oxidation, glutaminolysis) are used to determine the cell fate. However, few efforts have been made to understand the role of SIRTs on B lymphocytes metabolism and function. These cells are associated with humoral immune responses by secreting larger amounts of antibodies after differentiating into antibody-secreting cells. Besides, both the SIRTs and B lymphocytes are potential targets to treat several immune-mediated disorders, including cancer. Here, we provide an outlook of recent studies regarding the role of SIRTs in general cellular metabolism and B lymphocytes functions, pointing out the future perspectives of this field.
文摘The increasing incidence of obesity worldwide and its related cardiometabolic complications is an urgent public health problem. While weight gain results from a negative balance between the energy expenditure and calorie intake, recent research has demonstrated that several small organic molecules containing a four-carbon backbone can modulate this balance by favoring energy expenditure, and alleviating endoplasmic reticulum stress and oxidative stress. Such small molecules include the bacterially produced short chain fatty acid butyric acid, its chemically produced derivative 4-phenylbutyric acid, the main ketone body D-β-hydroxybutyrate- synthesized by the liver- and the recently discovered myokine β-aminoisobutyric acid. Conversely, another butyraterelated molecule, α-hydroxybutyrate, has been found to be an early predictor of insulin resistance and glucose intolerance. In this minireview, we summarize recent advances in the understanding of the mechanism of action of these molecules, and discuss their use as therapeutics to improve metabolic homeostasis or their detection as early biomarkers of incipient insulin resistance.
