Valproate increases dopamine transporter expression through histone acetylation and enhanced promoter binding of Nurr1.
Acetylation/drug effects; Animals; Butyrates/pharmacology; Cell Line; Cell Survival/drug effects; Dopamine Plasma Membrane Transport Proteins/*metabolism; Dopamine transporter; Dopaminergic Neurons/cytology/drug effects/metabolism; Dose-Response Relationship; Drug; Epigenesis; Epigenetics; Genetic; Genetic/drug effects; Group A; HDAC; Histone deacetylase; Histone Deacetylase Inhibitors/*pharmacology; Histone Deacetylases/metabolism; Histones/*drug effects/metabolism; Homeodomain Proteins/metabolism; Hydroxamic Acids/pharmacology; Member 2/*metabolism; Messenger/metabolism; Nuclear Receptor Subfamily 4; Nurr1; Pitx3; Promoter Regions; Rats; RNA; Transcription Factors/metabolism; Valproate; Valproic Acid/*pharmacology
The dopamine transporter (DAT) is the key regulator of dopaminergic transmission and is a target of several xenobiotics, including pesticides and pharmacological agents. Previously, we identified a prominent role for histone deacetylases in the regulation of DAT expression. Here, we utilized a rat dopaminergic cell line (N27) to probe the responsiveness of DAT mRNA expression to inhibitors of histone acetylation. Inhibition of histone deacetylases (HDACs) by valproate, butyrate and Trichostatin A led to a 3-10-fold increase in DAT mRNA expression, a 50% increase in protein levels, which were accompanied by increased H3 acetylation levels. To confirm the mechanism of valproate-mediated increase in DAT mRNA, chromatin immunoprecipitation (ChIP) assays were used and demonstrated a significant increase in enrichment of acetylation of histone 3 on lysines 9 and 14 (H3K9/K14ac) in the DAT promoter. Expression of Nurr1 and Pitx3, key regulators of DAT expression, were increased following valproate treatment and Nurr1 binding was enriched in the DAT promoter. Together, these results indicate that histone acetylation and subsequent enhancement of transcription factor binding are plausible mechanisms for DAT regulation by valproate and, perhaps, by other xenobiotics.
Green Ashley L; Zhan Le; Eid Aseel; Zarbl Helmut; Guo Grace L; Richardson Jason R
Neuropharmacology
2017
2017-10
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.neuropharm.2017.07.020" target="_blank" rel="noreferrer noopener">10.1016/j.neuropharm.2017.07.020</a>
Epigenetics in osteoarthritis: Potential of HDAC inhibitors as therapeutics.
*DNA methylation; *Epigenetics; *HDACs; *lncRNA; *miRNA; *Osteoarthritis; Animals; Epigenesis; Genetic; Histone Deacetylase Inhibitors/*therapeutic use; Humans; Osteoarthritis/*drug therapy/*genetics
Osteoarthritis (OA) is the most common joint disease and the leading cause of chronic disability in middle-aged and older populations worldwide. The development of disease modifying therapy for OA is in its infancy largely because the regulatory mechanisms for the molecular effectors of OA pathogenesis are poorly understood. Recent studies identified epigenetic events as a critical regulator of molecular players involved in the induction and development of OA. Epigenetic mechanisms include DNA methylation, non-coding RNA and histone modifications. The aim of this review is to briefly highlight the recent advances in the epigenetics of cartilage and potential of HDACs (Histone deacetylases) inhibitors in the therapeutic management of OA. We summarize the recent studies utilizing HDAC inhibitors as potential therapeutics for inhibiting disease progression and preventing the cartilage destruction in OA. HDACs control normal cartilage development and homeostasis and understanding the impact of HDACs inhibitors on the disease pathogenesis is of interest because of its importance in affecting overall cartilage health and homeostasis. These findings also shed new light on cartilage disease pathophysiology and provide substantial evidence that HDACs may be potential novel therapeutic targets in OA.
Khan Nazir M; Haqqi Tariq M
Pharmacological research
2018
2018-02
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.phrs.2017.08.007" target="_blank" rel="noreferrer noopener">10.1016/j.phrs.2017.08.007</a>
Glucose stimulates cholesterol 7alpha-hydroxylase gene transcription in human hepatocytes.
*Gene Expression Regulation; Acetylation; AMP-Activated Protein Kinases/metabolism; ATP Citrate (pro-S)-Lyase/genetics/metabolism; Bile Acids and Salts/metabolism; Cells; Cholesterol 7-alpha-Hydroxylase/genetics/*metabolism; Cultured; DNA-Binding Proteins/metabolism; Enzymologic; Epigenesis; Genes; Genetic; Glucose/*administration & dosage; Hep G2 Cells; Hepatocyte Nuclear Factor 4/metabolism; Hepatocytes/*enzymology/metabolism; Histones/metabolism; Humans; Hyperglycemia/enzymology/*metabolism; Messenger/metabolism; Methylation; Reporter; RNA; RNA Interference
Bile acids play important roles in the regulation of lipid, glucose, and energy homeostasis. Recent studies suggest that glucose regulates gene transcription in the liver. The aim of this study was to investigate the potential role of glucose in regulation of bile acid synthesis in human hepatocytes. High glucose stimulated bile acid synthesis and induced mRNA expression of cholesterol 7alpha-hydroxylase (CYP7A1), the key regulatory gene in bile acid synthesis. Activation of an AMP-activated protein kinase (AMPK) decreased CYP7A1 mRNA, hepatocyte nuclear factor 4alpha (HNF4alpha) protein, and binding to CYP7A1 chromatin. Glucose increased ATP levels to inhibit AMPK and induce HNF4alpha to stimulate CYP7A1 gene transcription. Furthermore, glucose increased histone acetylation and decreased H3K9 di- and tri-methylation in the CYP7A1 chromatin. Knockdown of ATP-citrate lyase, which converts citrate to acetyl-CoA, decreased histone acetylation and attenuated glucose induction of CYP7A1 mRNA expression. These results suggest that glucose signaling also induces CYP7A1 gene transcription by epigenetic regulation of the histone acetylation status. This study uncovers a novel link between hepatic glucose metabolism and bile acid synthesis. Glucose induction of bile acid synthesis may have an important implication in metabolic control of glucose, lipid, and energy homeostasis under normal and diabetic conditions.
Li Tiangang; Chanda Dipanjan; Zhang Yanqiao; Choi Hueng-Sik; Chiang John Y L
Journal of lipid research
2010
2010-04
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1194/jlr.M002782" target="_blank" rel="noreferrer noopener">10.1194/jlr.M002782</a>
Glucose and insulin induction of bile acid synthesis: mechanisms and implication in diabetes and obesity.
*Gene Expression Regulation; Animals; Bile Acids and Salts/*biosynthesis; Cholesterol 7-alpha-Hydroxylase/genetics/*metabolism; Cytoplasmic and Nuclear/genetics/metabolism; Diabetes Mellitus; Dietary Fats/administration & dosage/adverse effects; Enzymologic; Epigenesis; Experimental/genetics/*metabolism; Fasting/metabolism; Genetic/genetics; Glucose/*metabolism/pharmacology; Insulin/*metabolism; Mice; Obesity/etiology/genetics/*metabolism; Postprandial Period/genetics; Receptors; Sweetening Agents/pharmacology; Transgenic
Bile acids facilitate postprandial absorption of nutrients. Bile acids also activate the farnesoid X receptor (FXR) and the G protein-coupled receptor TGR5 and play a major role in regulating lipid, glucose, and energy metabolism. Transgenic expression of cholesterol 7alpha-hydroxylase (CYP7A1) prevented high fat diet-induced diabetes and obesity in mice. In this study, we investigated the nutrient effects on bile acid synthesis. Refeeding of a chow diet to fasted mice increased CYP7A1 expression, bile acid pool size, and serum bile acids in wild type and humanized CYP7A1-transgenic mice. Chromatin immunoprecipitation assays showed that glucose increased histone acetylation and decreased histone methylation on the CYP7A1 gene promoter. Refeeding also induced CYP7A1 in fxr-deficient mice, indicating that FXR signaling did not play a role in postprandial regulation of bile acid synthesis. In streptozocin-induced type I diabetic mice and genetically obese type II diabetic ob/ob mice, hyperglycemia increased histone acetylation status on the CYP7A1 gene promoter, leading to elevated basal Cyp7a1 expression and an enlarged bile acid pool with altered bile acid composition. However, refeeding did not further increase CYP7A1 expression in diabetic mice. In summary, this study demonstrates that glucose and insulin are major postprandial factors that induce CYP7A1 gene expression and bile acid synthesis. Glucose induces CYP7A1 gene expression mainly by epigenetic mechanisms. In diabetic mice, CYP7A1 chromatin is hyperacetylated, and fasting to refeeding response is impaired and may exacerbate metabolic disorders in diabetes.
Li Tiangang; Francl Jessica M; Boehme Shannon; Ochoa Adrian; Zhang Youcai; Klaassen Curtis D; Erickson Sandra K; Chiang John Y L
The Journal of biological chemistry
2012
2012-01
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1074/jbc.M111.305789" target="_blank" rel="noreferrer noopener">10.1074/jbc.M111.305789</a>
Cardiovascular Effects of Exposure to Cigarette Smoke and Electronic Cigarettes: Clinical Perspectives From the Prevention of Cardiovascular Disease Section Leadership Council and Early Career Councils of the American College of Cardiology.
atherogenesis; Cardiovascular Diseases – Etiology; Cardiovascular Diseases/*etiology; Electronic Cigarettes – Adverse Effects; Electronic Nicotine Delivery Systems/*adverse effects; Epigenesis; Genes; Genetic; genetic and epigenetic effects; Humans; Impact of Events Scale; Scales; smoke-free legislation; Smoking – Complications; Smoking – Legislation and Jurisprudence – United States; Smoking Cessation; Smoking/*adverse effects/legislation & jurisprudence; thrombosis; tobacco cessation; United States
Cardiovascular morbidity and mortality as a result of inhaled tobacco products continues to be a global healthcare crisis, particularly in low- and middle-income nations lacking the infrastructure to develop and implement effective public health policies limiting tobacco use. Following initiation of public awareness campaigns 50 years ago in the United States, considerable success has been achieved in reducing the prevalence of cigarette smoking and exposure to secondhand smoke. However, there has been a slowing of cessation rates in the United States during recent years, possibly caused by high residual addiction or fatigue from cessation messaging. Furthermore, tobacco products have continued to evolve faster than the scientific understanding of their biological effects. This review considers selected updates on the genetics and epigenetics of smoking behavior and associated cardiovascular risk, mechanisms of atherogenesis and thrombosis, clinical effects of smoking and benefits of cessation, and potential impact of electronic cigarettes on cardiovascular health.
Morris Pamela B; Ference Brian A; Jahangir Eiman; Feldman Dmitriy N; Ryan John J; Bahrami Hossein; El-Chami Mikhael F; Bhakta Shyam; Winchester David E; Al-Mallah Mouaz H; Sanchez Shields Monica; Deedwania Prakash; Mehta Laxmi S; Phan Binh An P; Benowitz Neal L
Journal of the American College of Cardiology
2015
2015-09
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.jacc.2015.07.037" target="_blank" rel="noreferrer noopener">10.1016/j.jacc.2015.07.037</a>
Turnover of histones and histone variants in postnatal rat brain: effects of alcohol exposure.
*2H2O-labeling; *Brain; *Genetic Variation; *Histone; *Mass spectrometry; *Post-translational modifications; *Postnatal alcohol exposure; *Turnover; Acetylation; Animal; Animals; Cell Proliferation; Disease Models; DNA Damage; Epigenesis; Female; Fetal Alcohol Spectrum Disorders/genetics/*metabolism; Genetic; Histones/*genetics/*metabolism; Humans; Post-Translational; Pregnancy; Protein Processing; Proteomics/*methods; Rats; Sprague-Dawley
BACKGROUND: Alcohol consumption during pregnancy is a significant public health problem and can result in a continuum of adverse outcomes to the fetus known as fetal alcohol spectrum disorders (FASD). Subjects with FASD show significant neurological deficits, ranging from microencephaly, neurobehavioral, and mental health problems to poor social adjustment and stress tolerance. Neurons are particularly sensitive to alcohol exposure. The neurotoxic action of alcohol, i.e., through ROS production, induces DNA damage and neuronal cell death by apoptosis. In addition, epigenetics, including DNA methylation, histone posttranslational modifications (PTMs), and non-coding RNA, play an important role in the neuropathology of FASD. However, little is known about the temporal dynamics and kinetics of histones and their PTMs in FASD. RESULTS: We examined the effects of postnatal alcohol exposure (PAE), an animal model of human third-trimester equivalent, on the kinetics of various histone proteins in two distinct brain regions, the frontal cortex, and the hypothalamus, using in vivo (2)H2O-labeling combined with mass spectrometry-based proteomics. We show that histones have long half-lives that are in the order of days. We also show that H3.3 and H2Az histone variants have faster turnovers than canonical histones and that acetylated histones, in general, have a faster turnover than unmodified and methylated histones. Our work is the first to show that PAE induces a differential reduction in turnover rates of histones in both brain regions studied. These alterations in histone turnover were associated with increased DNA damage and decreased cell proliferation in postnatal rat brain. CONCLUSION: Alterations in histone turnover might interfere with histone deposition and chromatin stability, resulting in deregulated cell-specific gene expression and therefore contribute to the development of the neurological disorders associated with FASD. Using in vivo (2)H2O-labeling and mass spectrometry-based proteomics might help in the understanding of histone turnover following alcohol exposure and could be of great importance in enabling researchers to identify novel targets and/or biomarkers for the prevention and management of fetal alcohol spectrum disorders.
Rachdaoui Nadia; Li Ling; Willard Belinda; Kasumov Takhar; Previs Stephen; Sarkar Dipak
Clinical epigenetics
2017
1905-07
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1186/s13148-017-0416-5" target="_blank" rel="noreferrer noopener">10.1186/s13148-017-0416-5</a>
Induction of vascular progenitor cells from endothelial cells stimulates coronary collateral growth.
*Collateral Circulation; *Coronary Circulation; Animal; Animals; Biomarkers/metabolism; Cell Differentiation; Cell Lineage; Cells; Coronary Occlusion/genetics/metabolism/pathology/physiopathology/*surgery; Coronary Vessels/metabolism/pathology/*physiopathology; Cultured; Developmental; Disease Models; Endothelial Cells/metabolism/pathology/*transplantation; Epigenesis; Gene Expression Profiling; Gene Expression Regulation; Genetic; Induced Pluripotent Stem Cells/metabolism/*transplantation; Mice; Muscle; Myocytes; Neovascularization; Physiologic; Rats; Regenerative Medicine/methods; Regional Blood Flow; Reverse Transcriptase Polymerase Chain Reaction; SCID; Smooth; Smooth Muscle/metabolism/pathology/*transplantation; Sprague-Dawley; Teratoma/metabolism/pathology; Time Factors; Transcription Factors/genetics/metabolism; Transduction; Vascular/metabolism/pathology/*physiopathology
RATIONALE: A well-developed coronary collateral circulation improves the morbidity and mortality of patients following an acute coronary occlusion. Although regenerative medicine has great potential in stimulating vascular growth in the heart, to date there have been mixed results, and the ideal cell type for this therapy has not been resolved. OBJECTIVE: To generate induced vascular progenitor cells (iVPCs) from endothelial cells, which can differentiate into vascular smooth muscle cells (VSMCs) or endothelial cells (ECs), and test their capability to stimulate coronary collateral growth. METHODS AND RESULTS: We reprogrammed rat ECs with the transcription factors Oct4, Klf4, Sox2, and c-Myc. A population of reprogrammed cells was derived that expressed pluripotent markers Oct4, SSEA-1, Rex1, and AP and hemangioblast markers CD133, Flk1, and c-kit. These cells were designated iVPCs because they remained committed to vascular lineage and could differentiate into vascular ECs and VSMCs in vitro. The iVPCs demonstrated better in vitro angiogenic potential (tube network on 2-dimensional culture, tube formation in growth factor reduced Matrigel) than native ECs. The risk of teratoma formation in iVPCs is also reduced in comparison with fully reprogrammed induced pluripotent stem cells (iPSCs). When iVPCs were implanted into myocardium, they engrafted into blood vessels and increased coronary collateral flow (microspheres) and improved cardiac function (echocardiography) better than iPSCs, mesenchymal stem cells, native ECs, and sham treatments. CONCLUSIONS: We conclude that iVPCs, generated by partially reprogramming ECs, are an ideal cell type for cell-based therapy designed to stimulate coronary collateral growth.
Yin Liya; Ohanyan Vahagn; Pung Yuh Fen; Delucia Angelo; Bailey Erin; Enrick Molly; Stevanov Kelly; Kolz Christopher L; Guarini Giacinta; Chilian William M
Circulation research
2012
2012-01
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1161/CIRCRESAHA.111.250126" target="_blank" rel="noreferrer noopener">10.1161/CIRCRESAHA.111.250126</a>