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Rabkin SW, Wong CN. Epigenetics in Heart Failure: Role of DNA Methylation in Potential Pathways Leading to Heart Failure with Preserved Ejection Fraction. Biomedicines 2023; 11:2815. [PMID: 37893188 PMCID: PMC10604152 DOI: 10.3390/biomedicines11102815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/21/2023] [Accepted: 09/26/2023] [Indexed: 10/29/2023] Open
Abstract
This review will focus on epigenetic modifications utilizing the DNA methylation mechanism, which is potentially involved in the pathogenesis of heart failure with preserved ejection fraction (HFpEF). The putative pathways of HFpEF will be discussed, specifically myocardial fibrosis, myocardial inflammation, sarcoplasmic reticulum Ca2+-ATPase, oxidative-nitrosative stress, mitochondrial and metabolic defects, as well as obesity. The relationship of HFpEF to aging and atrial fibrillation will be examined from the perspective of DNA methylation.
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Affiliation(s)
- Simon W. Rabkin
- Department of Medicine, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Division of Cardiology, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Chenille N. Wong
- Department of Medicine, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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2
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Chen F, Ghosh A, Lin J, Zhang C, Pan Y, Thakur A, Singh K, Hong H, Tang S. 5-lipoxygenase pathway and its downstream cysteinyl leukotrienes as potential therapeutic targets for Alzheimer's disease. Brain Behav Immun 2020; 88:844-855. [PMID: 32222525 DOI: 10.1016/j.bbi.2020.03.022] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 03/19/2020] [Accepted: 03/21/2020] [Indexed: 12/29/2022] Open
Abstract
5-lipoxygenase (ALOX5) is an enzyme involved in arachidonic acid (AA) metabolism, a metabolic pathway in which cysteinyl leukotrienes (CysLTs) are the resultant metabolites. Both ALOX5 and CysLTs are clinically significant in a number of inflammatory diseases, such as in asthma and allergic rhinitis, and drugs antagonizing the effect of these molecules have long been successfully used to counter these diseases. Interestingly, recent advances in 'neuroinflammation' research has led to the discovery of several novel inflammatory pathways regulating many cerebral pathologies, including the ALOX5 pathway. By means of pharmacological and genetic studies, both ALOX5 and CysLTs receptors have been shown to be involved in the pathogenesis of Alzheimer's disease (AD) and other neurodegenerative/neurological diseases, such as in Parkinson's disease, multiple sclerosis, and epilepsy. In both transgenic and sporadic models of AD, it has been shown that the levels of ALOX5/CysLTs are elevated, and that genetic/pharmacological interventions of these molecules can alleviate AD-related behavioral and pathological conditions. Clinical relevance of these molecules has also been found in AD brain samples. In this review, we aim to summarize such important findings on the role of ALOX5/CysLTs in AD pathophysiology, from both the cellular and the molecular aspects, and also discuss the potential of their blockers as possible therapeutic choices to curb AD-related conditions.
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Affiliation(s)
- Fang Chen
- Department of Pharmacy, the First Affiliated Hospital of Xiamen University, Xiamen, China; Department of Pharmacology and Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Arijit Ghosh
- Department of Pharmacology and Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Jingran Lin
- Department of Pharmacology and Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Chunteng Zhang
- School of Pharmacy, North China University of Science and Technology, Tangshan, China; Department of Pharmacology and Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Yining Pan
- Department of Medicine, Queen Mary Hospital, the University of Hong Kong, Hong Kong, China
| | - Abhimanyu Thakur
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Kunal Singh
- Department of Biotechnology, Noida Institute of Engineering & Technology, Greater Noida, India
| | - Hao Hong
- Department of Pharmacology and Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China.
| | - Susu Tang
- Department of Pharmacology and Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China.
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Heidari L, Ghaderian SMH, Vakili H, Salmani TA. Promoter methylation and functional variants in arachidonate 5-lipoxygenase and forkhead box protein O1 genes associated with coronary artery disease. J Cell Biochem 2019; 120:12360-12368. [PMID: 30825235 DOI: 10.1002/jcb.28501] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 12/10/2018] [Accepted: 12/14/2018] [Indexed: 01/08/2023]
Abstract
Coronary artery disease (CAD) is a multifactorial chronic inflammatory disease, which is the most common form of heart disease. This is one of the main causes of death in the United States. Inflammation is one of the key drivers of atherosclerotic plaque development. Forkhead box protein O1 (FOXO1s) family and 5-lipoxygenase make an important contribution to atherosclerosis. The aim of this study was to investigate the methylation pattern and polymorphism analysis of FOXO1 and arachidonate 5-lipoxygenase (ALOX5) promoter genes. We studied 50 patients with CAD and 50 age- and sex-matched healthy controls by high resolution melt technique. Overall, we found significant differences between patients and controls in terms of the promoter methylation of ALOX5 (P > 0.05). But there was no significant difference in FOXO1 promoter methylation between patient and controls. Single nucleotide polymorphisms genotyping of rs12762303 and rs2297627, in ALOX5 and FOXO1 genes were demonstrated a significant correlation between mutant allele and the risk of CAD, respectively. Furthermore, there were significant associations between CT + CC genotype and ALOX5 expression. Our findings demonstrated functional effects of single nucleotide polymorphisms (SNPs) and DNA methylation in ALOX5 on mentioned genes expression and they resulted in CAD progression.
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Affiliation(s)
- Laleh Heidari
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sayyed Mohammad Hossein Ghaderian
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Urogenital Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hossein Vakili
- Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Tayyeb Ali Salmani
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Li JG, Barrero C, Merali S, Praticò D. Five lipoxygenase hypomethylation mediates the homocysteine effect on Alzheimer's phenotype. Sci Rep 2017; 7:46002. [PMID: 28383037 PMCID: PMC5382538 DOI: 10.1038/srep46002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 03/07/2017] [Indexed: 12/11/2022] Open
Abstract
Environmental and genetic risk factors are implicated in the pathogenesis of Alzheimer’s disease (AD). However, how they interact and influence its pathogenesis remains to be investigated. High level of homocysteine (Hcy) is an AD risk factor and associates with an up-regulation of the ALOX5 gene. In the current paper we investigated whether this activation is responsible for the Hcy effect on the AD phenotype and the mechanisms involved. Triple transgenic mice were randomized to receive regular chow diet, a diet deficient in folate and B vitamins (Diet), which results in high Hcy, or the Diet plus zileuton, a specific ALOX5 inhibitor, for 7 months. Compared with controls, Diet-fed mice had a significant increase in Hcy levels, memory and learning deficits, up-regulation of the ALOX5 pathway, increased Aβ levels, tau phosphorylation, and synaptic pathology, which were absent in mice treated with zileuton. In vivo and vitro studies demonstrated that the mechanism responsible was the hypomethylation of the ALOX5 promoter. Our findings demonstrate that the up-regulation of the ALOX5 is responsible for the Hcy-dependent worsening of the AD phenotype in a relevant mouse model of the disease. The discovery of this previously unknown cross-talk between these two pathways could afford novel therapeutic opportunities for treating or halting AD.
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Affiliation(s)
- Jian-Guo Li
- Department of Pharmacology and Center for Translational Medicine, Lewis Katz School of Medicine, Temple University Philadelphia, PA 19140, USA
| | - Carlos Barrero
- Department of Pharmaceutical Sciences, Temple University Philadelphia, PA 19140, USA
| | - Salim Merali
- Department of Pharmaceutical Sciences, Temple University Philadelphia, PA 19140, USA
| | - Domenico Praticò
- Department of Pharmacology and Center for Translational Medicine, Lewis Katz School of Medicine, Temple University Philadelphia, PA 19140, USA
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Li J, Barrero C, Gupta S, Kruger WD, Merali S, Praticò D. Homocysteine modulates 5-lipoxygenase expression level via DNA methylation. Aging Cell 2017; 16:273-280. [PMID: 27896923 PMCID: PMC5334532 DOI: 10.1111/acel.12550] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2016] [Indexed: 12/02/2022] Open
Abstract
Elevated levels of homocysteinemia (Hcy), a risk factor for late-onset Alzheimer's disease (AD), have been associated with changes in cell methylation. Alzheimer's disease is characterized by an upregulation of the 5-lipoxygenase (5LO), whose promoter is regulated by methylation. However, whether Hcy activates 5LO enzymatic pathway by influencing the methylation status of its promoter remains unknown. Brains from mice with high Hcy were assessed for the 5LO pathway and neuronal cells exposed to Hcy implemented to study the mechanism(s) regulating 5LO expression levels and the effect on amyloid β formation. Diet- and genetically induced high Hcy resulted in 5LO protein and mRNA upregulation, which was associated with a significant increase of the S-adenosylhomocysteine (SAH)/S-adenosylmethionine ratio, and reduced DNA methyltrasferases and hypomethylation of 5-lipoxygenase DNA. In vitro studies confirmed these results and demonstrated that the mechanism involved in the Hcy-dependent 5LO activation and amyloid β formation is DNA hypomethylation secondary to the elevated levels of SAH. Taken together these findings represent the first demonstration that Hcy directly influences 5LO expression levels and establish a previously unknown cross talk between these two pathways, which is highly relevant for AD pathogenesis. The discovery of such a novel link not only provides new mechanistic insights in the neurobiology of Hcy, but most importantly new therapeutic opportunities for the individuals bearing this risk factor for the disease.
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Affiliation(s)
- Jian‐Guo Li
- Department of Pharmacology and Center for Translational MedicineLewis Katz School of MedicinePhiladelphiaPA19140USA
| | - Carlos Barrero
- Department of Pharmaceutical SciencesTemple University PhiladelphiaPhiladelphiaPA19140USA
| | - Sapna Gupta
- Cancer Biology Program Fox Chase Cancer CenterTemple University PhiladelphiaPhiladelphiaPA19140USA
| | - Warren D. Kruger
- Cancer Biology Program Fox Chase Cancer CenterTemple University PhiladelphiaPhiladelphiaPA19140USA
| | - Salim Merali
- Department of Pharmaceutical SciencesTemple University PhiladelphiaPhiladelphiaPA19140USA
| | - Domenico Praticò
- Department of Pharmacology and Center for Translational MedicineLewis Katz School of MedicinePhiladelphiaPA19140USA
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The Lipoxygenases: Their Regulation and Implication in Alzheimer's Disease. Neurochem Res 2015; 41:243-57. [PMID: 26677076 PMCID: PMC4773476 DOI: 10.1007/s11064-015-1776-x] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/06/2015] [Accepted: 11/14/2015] [Indexed: 02/03/2023]
Abstract
Inflammatory processes and alterations of lipid metabolism play a crucial role in Alzheimer’s disease (AD) and other neurodegenerative disorders. Polyunsaturated fatty acids (PUFA) metabolism impaired by cyclooxygenases (COX-1, COX-2), which are responsible for formation of several eicosanoids, and by lipoxygenases (LOXs) that catalyze the addition of oxygen to linolenic, arachidonic (AA), and docosahexaenoic acids (DHA) and other PUFA leading to formation of bioactive lipids, significantly affects the course of neurodegenerative diseases. Among several isoforms, 5-LOX and 12/15-LOX are especially important in neuroinflammation/neurodegeneration. These two LOXs are regulated by substrate concentration and availability, and by phosphorylation/dephosphorylation through protein kinases PKA, PKC and MAP-kinases, including ERK1/ERK2 and p38. The protein/protein interaction also is involved in the mechanism of 5-LOX regulation through FLAP protein and coactosin-like protein. Moreover, non-heme iron and calcium ions are potent regulators of LOXs. The enzyme activity significantly depends on the cell redox state and is differently regulated by various signaling pathways. 5-LOX and 12/15-LOX convert linolenic acid, AA, and DHA into several bioactive compounds e.g. hydroperoxyeicosatetraenoic acids (5-HPETE, 12S-HPETE, 15S-HPETE), which are reduced to corresponding HETE compounds. These enzymes synthesize several bioactive lipids, e.g. leucotrienes, lipoxins, hepoxilins and docosahexaenoids. 15-LOX is responsible for DHA metabolism into neuroprotectin D1 (NPD1) with significant antiapoptotic properties which is down-regulated in AD. In this review, the regulation and impact of 5-LOX and 12/15-LOX in the pathomechanism of AD is discussed. Moreover, we describe the role of several products of LOXs, which may have significant pro- or anti-inflammatory activity in AD, and the cytoprotective effects of LOX inhibitors.
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The role of mid-chain hydroxyeicosatetraenoic acids in the pathogenesis of hypertension and cardiac hypertrophy. Arch Toxicol 2015; 90:119-36. [PMID: 26525395 DOI: 10.1007/s00204-015-1620-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 10/19/2015] [Indexed: 12/16/2022]
Abstract
The incidence, prevalence, and hospitalization rates associated with cardiovascular diseases (CVDs) are projected to increase substantially in the world. Understanding of the biological and pathophysiological mechanisms of survival can help the researchers to develop new management modalities. Numerous experimental studies have demonstrated that mid-chain HETEs are strongly involved in the pathogenesis of the CVDs. Mid-chain HETEs are biologically active eicosanoids that result from the metabolism of arachidonic acid (AA) by both lipoxygenase and CYP1B1 (lipoxygenase-like reaction). Therefore, identifying the localizations and expressions of the lipoxygenase and CYP1B1 and their associated AA metabolites in the cardiovascular system is of major importance in understanding their pathological roles. Generally, the expression of these enzymes is shown to be induced during several CVDs, including hypertension and cardiac hypertrophy. The induction of these enzymes is associated with the generation of mid-chain HETEs and subsequently causation of cardiovascular events. Of interest, inhibiting the formation of mid-chain HETEs has been reported to confer a protection against different cardiac hypertrophy and hypertension models such as angiotensin II, Goldblatt, spontaneously hypertensive rat and deoxycorticosterone acetate (DOCA)-salt-induced models. Although the exact mechanisms of mid-chain HETEs-mediated cardiovascular dysfunction are not fully understood, the present review proposes several mechanisms which include activating G-protein-coupled receptor, protein kinase C, mitogen-activated protein kinases, and nuclear factor kappa B. This review provides a clear understanding of the role of mid-chain HETEs in the pathogenesis of cardiovascular diseases and their importance as novel targets in the treatment for hypertension and cardiac hypertrophy.
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5-lipoxygenase-activating protein as a modulator of olanzapine-induced lipid accumulation in adipocyte. J Lipids 2013; 2013:864593. [PMID: 23762565 PMCID: PMC3677661 DOI: 10.1155/2013/864593] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 05/08/2013] [Accepted: 05/10/2013] [Indexed: 01/21/2023] Open
Abstract
Experiments were performed in 3T3-L1 preadipocytes differentiated in vitro into adipocytes. Cells were treated with olanzapine and a 5-lipoxygenase (5-LOX) activating protein (FLAP) inhibitor MK-886. Lipid content was measured using an Oil Red O assay; 5-LOX and FLAP mRNA content was measured using quantitative real-time PCR; the corresponding protein contents were measured using quantitative Western blot assay. Olanzapine did not affect the cell content of 5-LOX mRNA and protein; it decreased FLAP mRNA and protein content at day five but not 24 hours after olanzapine addition. In the absence of MK-886, low concentrations of olanzapine increased lipid content only slightly, whereas a 56% increase was induced by 50 μM olanzapine. A 5-day cotreatment with 10 μM MK-886 potentiated the lipid increasing action of low concentrations of olanzapine. In contrast, in the presence of 50 μM olanzapine nanomolar and low micromolar concentrations of MK-886 reduced lipid content. These data suggest that FLAP system in adipocytes is affected by olanzapine and that it may modify how these cells respond to the second-generation antipsychotic drugs (SGADs). Clinical studies could evaluate whether the FLAP/5-LOX system could play a role in setting a variable individual susceptibility to the metabolic side effects of SGADs.
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Chen H, Dzitoyeva S, Manev H. Effect of aging on 5-hydroxymethylcytosine in the mouse hippocampus. Restor Neurol Neurosci 2013; 30:237-45. [PMID: 22426040 DOI: 10.3233/rnn-2012-110223] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE Aging is believed to affect epigenetic marking of brain DNA with 5-methylcytosine (5mC) and possibly via the 5mC to 5-hydroxymethylcytosine (5hmC) conversion by TET (ten-eleven translocation) enzymes. We investigated the impact of aging on hippocampal DNA 5-hydroxymethylation including in the sequence of aging-susceptible 5-lipoxygenase (5-LOX) gene. METHODS Hippocampal samples were obtained from C57BL6 mice. Cellular 5hmC localization was determined by immunofluorescence. The global 5mC and 5hmC contents were measured with the corresponding ELISA. The 5-LOX 5hmC content was measured using a glucosyltransferase/enzymatic restriction digest assay. TET mRNA was measured using qRT-PCR. RESULTS Global hippocampal 5hmC content increased during aging as did the 5hmC content in the 5-LOX gene. This occurred without alterations of TET1-3 mRNAs and without changes in the content of 8-hydroxy-2-deoxy-guanosine, a marker of non-enzymatic DNA oxidation. CONCLUSIONS The aging-associated increase of hippocampal 5hmC content (global and 5-LOX) appears to be unrelated to oxidative stress. It may be driven by an altered activity but not by the increased expression of the three TET enzymes. Global 5hmC content was increased during aging in the absence of 5mC decrease, suggesting that 5hmC could act as an epigenetic marker and not only as an intermediary in DNA demethylation. Further research is needed to elucidate the functional implications of the impact of aging on hippocampal cytosine hydroxymethylation.
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Affiliation(s)
- Hu Chen
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, USA
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Chen H, Dzitoyeva S, Manev H. Effect of valproic acid on mitochondrial epigenetics. Eur J Pharmacol 2012; 690:51-9. [PMID: 22728245 DOI: 10.1016/j.ejphar.2012.06.019] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 05/24/2012] [Accepted: 06/10/2012] [Indexed: 10/28/2022]
Abstract
Valproic acid (valproate), an anticonvulsant and a mood stabilizer, is a potent histone deacetylase inhibitor and a widely utilized pharmacological tool for neuroepigenetic research including DNA methylation. However, only nuclear but not mitochondrial DNA (mtDNA) has been investigated for the effects of valproate on the formation of 5-methylcytosine (5 mC) and 5-hydroxymethylcytosine (5 hmC). Using mouse 3T3-L1 cells, we investigated the effects of short (1 day) and prolonged (3 days) valproate treatment on global mtDNA 5 mC content, global and mtDNA sequence-specific 5 hmC content, mRNA levels for ten-eleven-translocation (TET) enzymes involved in 5 hmC formation, and the mitochondrial content of TET proteins. Only 5 hmC but not 5 mC content in mtDNA was affected (decreased) by valproate, and only after the prolonged treatment. This action of valproate was mimicked by MS-275, a class I histone deacetylase inhibitor. The prolonged but not the short valproate treatment decreased the expression of Tet1 mRNA and reduced the mitochondrial content of the TET1 protein. Hence, a likely scenario for a valproate-induced 5 hmC decrease in mtDNA may involve nuclear histone deacetylase inhibition (mitochondria do not contain histones) causing the initial increase of Tet1 transcription, which is followed by a delayed compensatory decrease of Tet1 expression and a reduced presence of TET1 protein in mitochondria. Further research is needed to elucidate the functional implications of epigenetic modifications of mtDNA. The observed effects of valproate on mitochondrial epigenetics may have implications for a better understanding of both therapeutic and unwanted effects of this drug and possibly other histone deacetylase inhibitors.
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Affiliation(s)
- Hu Chen
- The Psychiatric Institute, University of Illinois at Chicago, Department of Psychiatry, 1601 West Taylor Street, M/C912, Chicago, IL60612, USA
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Effect of aging on 5-hydroxymethylcytosine in brain mitochondria. Neurobiol Aging 2012; 33:2881-91. [PMID: 22445327 DOI: 10.1016/j.neurobiolaging.2012.02.006] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 01/18/2012] [Accepted: 02/09/2012] [Indexed: 12/21/2022]
Abstract
Nuclear epigenetics of the mammalian brain is modified during aging. Little is known about epigenetic modifications of mitochondrial DNA (mtDNA). We analyzed brain samples of 4- and 24-month-old mice and found that aging decreased mtDNA 5-hydroxymethylcytosine (5hmC) but not 5-methylcytosine (5mC) levels in the frontal cortex but not the cerebellum. Transcript levels of selected mtDNA-encoded genes increased during aging in the frontal cortex only. Aging affected the expression of enzymes involved in 5-methylcytosine and 5-hydroxymethylcytosine synthesis (mitochondrial DNA methyltransferase 1 [mtDNMT1] and ten-eleven-translocation [TET]1-TET3, respectively). In the frontal cortex, aging decreased mtDNMT1 messenger RNA (mRNA) levels without affecting TET1-TET3 mRNAs. In the cerebellum, TET2 and TET3 mRNA content was increased but mtDNMT1 mRNA was unaffected. Using Western immunoblotting of samples from primary neuronal cultures, we found TET immunoreactivity in the mitochondrial fraction. At the single cell level, TET immunoreactivity was detected in the nucleus and in the perinuclear/intraneurite areas where it frequently colocalized with a mitochondrial marker. Our results demonstrated the presence and susceptibility to aging of mitochondrial epigenetic mechanisms in the mammalian brain.
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Abstract
Western societies are rapidly aging, and cardiovascular diseases are the leading cause of death. In fact, age and cardiovascular diseases are positively correlated, and disease syndromes affecting the heart reach epidemic proportions in the very old. Genetic variations and molecular adaptations are the primary contributors to the onset of cardiovascular disease; however, molecular links between age and heart syndromes are complex and involve much more than the passage of time. Changes in CM (cardiomyocyte) structure and function occur with age and precede anatomical and functional changes in the heart. Concomitant with or preceding some of these cellular changes are alterations in gene expression often linked to signalling cascades that may lead to a loss of CMs or reduced function. An understanding of the intrinsic molecular mechanisms underlying these cascading events has been instrumental in forming our current understanding of how CMs adapt with age. In the present review, we describe the molecular mechanisms underlying CM aging and how these changes may contribute to the development of cardiovascular diseases.
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Chouliaras L, van den Hove DLA, Kenis G, Dela Cruz J, Lemmens MAM, van Os J, Steinbusch HWM, Schmitz C, Rutten BPF. Caloric restriction attenuates age-related changes of DNA methyltransferase 3a in mouse hippocampus. Brain Behav Immun 2011; 25:616-23. [PMID: 21172419 DOI: 10.1016/j.bbi.2010.11.016] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 11/08/2010] [Accepted: 11/28/2010] [Indexed: 01/06/2023] Open
Abstract
Recent studies have suggested that DNA methylation is implicated in age-related changes in gene expression as well as in cognition. DNA methyltransferase 3a (Dnmt3a), which catalyzes DNA methylation, is essential for memory formation and underlying changes in neuronal and synaptic plasticity. Because caloric restriction (CR) and upregulation of antioxidants have been suggested as strategies to attenuate age-related alterations in the brain, we hypothesized that both a diet restricted in calories and transgenic overexpression of normal human Cu/Zn superoxide dismutase 1 (SOD) attenuate age-related changes in Dnmt3a in the aging mouse hippocampus. For this purpose, we performed qualitative and quantitative analyses of Dnmt3a-immunoreactivity (IR) for the hippocampal dentate gyrus (DG), CA3 and CA1-2 regions in 12- and 24-month-old mice from 4 groups, i.e. (1) wild-type (WT) mice on a control diet (WT-CD), (2) SOD-CD mice, (3) WT mice on CR (WT-CR), and (4) SOD-CR. Qualitative analyses revealed two types of Dnmt3a immunoreactive cells: type I cells--present throughout all hippocampal cell layers showing moderate levels of nuclear Dnmt3a-IR, and type II cells--a subpopulation of hippocampal cells showing very intense nuclear Dnmt3a-IR, and colocalization with Bromodeoxyuridine. Quantitative analyses indicated that the age-related increase in Dnmt3a-IR within the CA3 and CA1-2 in type I cells was attenuated by CR, but not by SOD overexpression. In contrast, the density of type II Dnmt3a immunoreactive cells showed an age-related reduction, without significant effects of both CR and SOD. These changes in Dnmt3a levels in the mouse hippocampus may have a significant impact on gene expression and associated cognitive functioning.
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Affiliation(s)
- L Chouliaras
- School for Mental Health and Neuroscience (MHeNS), Faculty of Health, Medicine and Life Sciences, European Graduate School of Neuroscience (EURON), Maastricht University Medical Centre, P.O. Box 616, 6200 MD Maastricht, The Netherlands
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Manev H, Chen H, Dzitoyeva S, Manev R. Cyclooxygenases and 5-lipoxygenase in Alzheimer's disease. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:315-9. [PMID: 20691748 PMCID: PMC3033490 DOI: 10.1016/j.pnpbp.2010.07.032] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 07/20/2010] [Accepted: 07/29/2010] [Indexed: 11/26/2022]
Abstract
Typically, cyclooxygenases (COXs) and 5-lipoxygenase (5-LOX), enzymes that generate biologically active lipid molecules termed eicosanoids, are considered inflammatory. Hence, their putative role in Alzheimer's disease (AD) has been explored in the framework of possible inflammatory mechanisms of AD pathobiology. More recent data indicate that these enzymes and the biologically active lipid molecules they generate could influence the functioning of the central nervous system and the pathobiology of neurodegenerative disorders such as AD via mechanisms different from classical inflammation. These mechanisms include the cell-specific localization of COXs and 5-LOX in the brain, the type of lipid molecules generated by the activity of these enzymes, the type and the localization of receptors selective for a type of lipid molecule, and the putative interactions of the COXs and 5-LOX pathways with intracellular components relevant for AD such as the gamma-secretase complex. Considering the importance of these multiple and not necessarily inflammatory mechanisms may help us delineate the exact nature of the involvement of the brain COXs and 5-LOX in AD and would reinvigorate the search for novel targets for AD therapy.
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Affiliation(s)
- Hari Manev
- Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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Chen H, Dzitoyeva S, Manev H. 5-Lipoxygenase in mouse cerebellar Purkinje cells. Neuroscience 2010; 171:383-9. [PMID: 20851170 DOI: 10.1016/j.neuroscience.2010.09.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 09/09/2010] [Accepted: 09/11/2010] [Indexed: 10/19/2022]
Abstract
It has been suggested that the enzymatic pathway of 5-lipoxygenase (5-LOX) influences brain functioning and pathobiology. The mRNAs for both the enzyme 5-LOX and its activating protein FLAP have been found in the cerebellum. In this work, we investigated the cellular expression of 5-LOX in the adult mouse cerebellar cortex. We used the in situ mRNA hybridization assay, immunocytochemistry, laser capture microdissection, and our previously developed method for assaying the DNA methylation status of a putative mouse 5-LOX promoter. Since both 5-LOX mRNA in situ hybridization signal and FLAP immunoreactivity co-localize with calbindin 28 kD immunoreactivity (a Purkinje cell marker) but not with S-100β immunoreactivity (a Bergmann glia marker), the suggestion is that the 5-LOX pathway is expressed in cerebellar Purkinje cells. We found that methylation in the sites targeted by methylation-sensitive restriction endonucleases AciI and HinP1I but not BstUI and HpaII was greater in DNA samples obtained from a high-5-LOX-expressing cerebellar region (Purkinje cells) versus a low-5-LOX-expressing region (the molecular cell layer), suggesting a possible epigenetic contribution to the cell-specific 5-LOX expression in the cerebellum. We propose that Purkinje cell-localized 5-LOX and FLAP expression may be involved in the cerebellar synthesis of leukotrienes and/or could influence the Dicer-mediated microRNA formation and processes of neuroplasticity.
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Affiliation(s)
- H Chen
- The Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL 60612, USA
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