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1.
Neural Regen Res ; 13(2): 252-256, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29557374

RESUMO

Ischemic brain injury triggers neuronal cell death by apoptosis via caspase activation and by necroptosis through activation of the receptor-interacting protein kinases (RIPK) associated with the tumor necrosis factor-alpha (TNF-α)/death receptor. Recent evidence shows RIPK inhibitors are neuroprotective and alleviate ischemic brain injury in a number of animal models, however, most have not yet undergone clinical trials and safety in humans remains in question. Dabrafenib, originally identified as a B-raf inhibitor that is currently used to treat melanoma, was later revealed to be a potent RIPK3 inhibitor at micromolar concentrations. Here, we investigated whether Dabrafenib would show a similar neuroprotective effect in mice subjected to ischemic brain injury by photothrombosis. Dabrafenib administered intraperitoneally at 10 mg/kg one hour after photothrombosis-induced focal ischemic injury significantly reduced infarct lesion size in C57BL6 mice the following day, accompanied by a markedly attenuated upregulation of TNF-α. However, subsequent lower doses (5 mg/kg/day) failed to sustain this neuroprotective effect after 4 days. Dabrafenib blocked lipopolysaccharides-induced activation of TNF-α in bone marrow-derived macrophages, suggesting that Dabrafenib may attenuate TNF-α-induced necroptotic pathway after ischemic brain injury. Since Dabrafenib is already in clinical use for the treatment of melanoma, it might be repurposed for stroke therapy.

2.
Neural Regen Res ; 12(11): 1762-1764, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29239311

RESUMO

Ischemic brain injury triggers an inflammatory response. This response is necessary to clear damaged brain tissue but can also exacerbate brain injury. Microglia are the innate immune cells of the brain that execute this critical function. In healthy brain, microglia perform a housekeeping function, pruning unused synapses between neurons. However, microglia become activated to an inflammatory phenotype upon brain injury. Interferon regulatory factors modulate microglial activation and their production of inflammatory cytokines. This review briefly discusses recent findings pertaining to these regulatory mechanisms in the context of stroke recovery.

3.
Lancet Neurol ; 16(11): 898-907, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29029846

RESUMO

BACKGROUND: Restless legs syndrome is a prevalent chronic neurological disorder with potentially severe mental and physical health consequences. Clearer understanding of the underlying pathophysiology is needed to improve treatment options. We did a meta-analysis of genome-wide association studies (GWASs) to identify potential molecular targets. METHODS: In the discovery stage, we combined three GWAS datasets (EU-RLS GENE, INTERVAL, and 23andMe) with diagnosis data collected from 2003 to 2017, in face-to-face interviews or via questionnaires, and involving 15 126 cases and 95 725 controls of European ancestry. We identified common variants by fixed-effect inverse-variance meta-analysis. Significant genome-wide signals (p≤5 × 10-8) were tested for replication in an independent GWAS of 30 770 cases and 286 913 controls, followed by a joint analysis of the discovery and replication stages. We did gene annotation, pathway, and gene-set-enrichment analyses and studied the genetic correlations between restless legs syndrome and traits of interest. FINDINGS: We identified and replicated 13 new risk loci for restless legs syndrome and confirmed the previously identified six risk loci. MEIS1 was confirmed as the strongest genetic risk factor for restless legs syndrome (odds ratio 1·92, 95% CI 1·85-1·99). Gene prioritisation, enrichment, and genetic correlation analyses showed that identified pathways were related to neurodevelopment and highlighted genes linked to axon guidance (associated with SEMA6D), synapse formation (NTNG1), and neuronal specification (HOXB cluster family and MYT1). INTERPRETATION: Identification of new candidate genes and associated pathways will inform future functional research. Advances in understanding of the molecular mechanisms that underlie restless legs syndrome could lead to new treatment options. We focused on common variants; thus, additional studies are needed to dissect the roles of rare and structural variations. FUNDING: Deutsche Forschungsgemeinschaft, Helmholtz Zentrum München-Deutsches Forschungszentrum für Gesundheit und Umwelt, National Research Institutions, NHS Blood and Transplant, National Institute for Health Research, British Heart Foundation, European Commission, European Research Council, National Institutes of Health, National Institute of Neurological Disorders and Stroke, NIH Research Cambridge Biomedical Research Centre, and UK Medical Research Council.


Assuntos
Predisposição Genética para Doença/genética , Estudo de Associação Genômica Ampla , Síndrome das Pernas Inquietas/epidemiologia , Síndrome das Pernas Inquietas/genética , Proteínas de Ligação a DNA/genética , Grupo com Ancestrais do Continente Europeu , Proteínas Ligadas por GPI/genética , Humanos , Proteínas do Tecido Nervoso/genética , Netrinas , Semaforinas/genética , Fatores de Transcrição/genética
4.
Sci Rep ; 7(1): 9836, 2017 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-28852125

RESUMO

Enhanced postnatal care (EPC) increases resilience to adversity in adulthood. Since microglia participate in shaping neural circuits, we asked how ablation of an inflammation-suppressing factor IRF2BP2 (Interferon Regulatory Factor 2 Binding Protein 2) in microglia would affect the responses to EPC. Mice lacking IRF2BP2 in microglia (KO) and littermate controls (WT) were subjected to EPC during the first 3 weeks after birth. EPC reduced anxiety in WT but not KO mice. This was associated with reduced inflammatory cytokine expression in the hypothalamus. Whole genome RNAseq profiling of the hypothalamus identified 101 genes whose expression was altered by EPC: 95 in WT, 11 in KO, with 5 in common that changed in opposite directions. Proteoglycan 4 (Prg4), prostaglandin D2 synthase (Ptgds) and extracellular matrix protease inhibitor Itih2 were suppressed by EPC in WT but elevated in KO mice. On the other hand, the glutamate transporter VGLUT1 (Slc17a7) was increased by EPC in WT but not KO mice. Prostaglandin D2 (PGD2) is known to enhance microglial inflammation and promote Gfap expression. ELISA confirmed reduced PGD2 in the hypothalamus of WT mice after EPC, associated with reduced Gfap expression. Our study suggests that the anxiety-reducing effect of EPC operates by suppressing microglial inflammation, likely by reducing neuronal prostaglandin D2 production.

5.
Front Cell Neurosci ; 11: 201, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28769762

RESUMO

Ischemic stroke causes neuronal cell death and triggers a cascade of inflammatory signals that contribute to secondary brain damage. Microglia, the brain-resident macrophages that remove dead neurons, play a critical role in the brain's response to ischemic injury. Our previous studies showed that IRF2 binding protein 2 (IRF2BP2) regulates peripheral macrophage polarization, limits their inflammatory response and reduces susceptibility to atherosclerosis. Here, we show that loss of IRF2BP2 in microglia leads to increased inflammatory cytokine expression in response to lipopolysaccharide challenge and impaired activation of anti-inflammatory markers in response to interleukin-4 (IL4) stimulation. Focal ischemic brain injury of the sensorimotor cortex induced by photothrombosis caused more severe functional deficits in mice with IRF2BP2 ablated in macrophages/microglia, associated with elevated expression of inflammatory cytokines in the brain. These mutant mice had larger infarctions 4 days after stroke associated with fewer anti-inflammatory M2 microglia/macrophages recruited to the peri-infarct area, suggesting an impaired clearance of injured tissues. Since IRF2BP2 modulates interferon signaling, and interferon beta (IFNß) has been reported to be anti-inflammatory and reduce ischemic brain injury, we asked whether loss of IRF2BP2 in macrophages/microglia would affect the response to IFNß in our stroke model. IFNß suppressed inflammatory cytokine production of macrophages and reduced infarct volumes at 4 days after photothrombosis in wild type mice. The anti-inflammatory effect of IFNß was lost in IRF2BP2-deficient macrophages and IFNß failed to protect mice lacking IRF2BP2 in macrophages/microglia from ischemic injury. In summary, IRF2BP2 expression in macrophages/microglia is important to limit inflammation and stroke injury, in part by mediating the beneficial effect of IFNß.

6.
Circulation ; 135(24): 2336-2353, 2017 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-28461624

RESUMO

BACKGROUND: Common diseases such as coronary heart disease (CHD) are complex in etiology. The interaction of genetic susceptibility with lifestyle factors may play a prominent role. However, gene-lifestyle interactions for CHD have been difficult to identify. Here, we investigate interaction of smoking behavior, a potent lifestyle factor, with genotypes that have been shown to associate with CHD risk. METHODS: We analyzed data on 60 919 CHD cases and 80 243 controls from 29 studies for gene-smoking interactions for genetic variants at 45 loci previously reported to be associated with CHD risk. We also studied 5 loci associated with smoking behavior. Study-specific gene-smoking interaction effects were calculated and pooled using fixed-effects meta-analyses. Interaction analyses were declared to be significant at a P value of <1.0×10-3 (Bonferroni correction for 50 tests). RESULTS: We identified novel gene-smoking interaction for a variant upstream of the ADAMTS7 gene. Every T allele of rs7178051 was associated with lower CHD risk by 12% in never-smokers (P=1.3×10-16) in comparison with 5% in ever-smokers (P=2.5×10-4), translating to a 60% loss of CHD protection conferred by this allelic variation in people who smoked tobacco (interaction P value=8.7×10-5). The protective T allele at rs7178051 was also associated with reduced ADAMTS7 expression in human aortic endothelial cells and lymphoblastoid cell lines. Exposure of human coronary artery smooth muscle cells to cigarette smoke extract led to induction of ADAMTS7. CONCLUSIONS: Allelic variation at rs7178051 that associates with reduced ADAMTS7 expression confers stronger CHD protection in never-smokers than in ever-smokers. Increased vascular ADAMTS7 expression may contribute to the loss of CHD protection in smokers.


Assuntos
Doença das Coronárias/genética , Doença das Coronárias/prevenção & controle , Loci Gênicos/genética , Predisposição Genética para Doença/genética , Fumar/genética , Proteína ADAMTS7/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Células Cultivadas , Doença das Coronárias/epidemiologia , Vasos Coronários/patologia , Vasos Coronários/fisiologia , Feminino , Interação Gene-Ambiente , Predisposição Genética para Doença/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Fumar/efeitos adversos , Fumar/epidemiologia
7.
Cardiovasc Res ; 113(8): 973-983, 2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-28158393

RESUMO

Aims: With the availability of genome-wide genotype data from GWAS studies, it is now possible to compute the genetic relatedness among individuals and estimate its contribution (SNP-based heritability) to phenotypic variance using Mixed-Linear-Models (MLMs). The estimated heritability can be partitioned according to biological features to gain insight into the genetic architecture of a disease. Here, we aimed to examine the genetic structure of coronary artery disease (CAD). Methods and results: We investigated the genetic structure of CAD using 3,163,082 autosomal genome-wide SNPs (MAF ≥ 0.01) and MLMs in a sample of genetically 'unrelated' 4535 cases and 2977 controls. We find that genome-wide SNPs explain 22% of liability to CAD (55% of narrow-sense heritability) and sex-differences in CAD is not due to common SNPs on autosomal chromosomes. Heritability was proportionally distributed across the allele frequency spectrum and notably enriched among genic SNPs. We identified a number of modules that are significantly associated with CAD including: Dendritic cells stimulation; Basigin interactions; and a Cancer module. Of note, genes involved in inflammation account for one-fifth of SNP-based heritability. Heritability-enrichment analysis showed significant enrichment in epigenetic sites associated with transcriptionally activity; namely, enhancers, H3K9ac/H3K27ac/H3K4me1/H3K4me3 histone modifications, and Fetal DNase I hypersensitivity sites whereas heritability was highly depleted in transcriptionally repressed regions. Conclusions: More individual SNP associations will be detected for CAD as sample size increases. The identified modules provide further biological insight for CAD and highlight the importance of immune-mediated processes in CAD pathogenesis. Finally, we showed that genetic liability to CAD is mainly attributed to epigenetic sites associated with transcriptional activity which encourage the design of custom sequencing/genotyping panels based on transcriptionally active regions.


Assuntos
Doença da Artéria Coronariana/genética , Doença da Artéria Coronariana/imunologia , Epigênese Genética , Predisposição Genética para Doença/genética , Polimorfismo de Nucleotídeo Único/genética , Transcrição Genética , Frequência do Gene/genética , Genótipo , Humanos , Modelos Lineares , Fenótipo
8.
Curr Atheroscler Rep ; 18(12): 77, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27815828

RESUMO

The notion that gene expression signatures in blood can serve as biomarkers of disease states is not new. In the case of atherosclerosis, and coronary artery disease in particular, whether changes in gene expression in peripheral blood mononuclear cells reflects disease processes occurring in the vessel wall remains controversial. When comparing 15 studies that identified 706 differentially expressed genes, only 23 genes were replicated in 2 to 3 studies, at most. This low level of replication may reflect sample sizes too small to overcome heterogeneity in the response to disease. Genetic differences affect how each person responds to disease and what genes are altered. Recent studies with larger cohorts (over 5000 individuals) that considered the effect of common genetic variants still could not claim disease signature genes as biomarkers suggesting that even larger case-control studies will be required to achieve the required statistical power. On the other hand, out of 7 studies that identified 58 microRNAs, 12 were concordant in 2 or more studies, suggesting that microRNAs may be less affected by genetic differences and more accurately reflect the disease process. Here, we review the current state of knowledge on expression profiling and its utility for predicting coronary artery disease status and mortality.


Assuntos
Aterosclerose/genética , Transcriptoma , Biomarcadores/análise , Perfilação da Expressão Gênica , Humanos , Leucócitos Mononucleares/metabolismo , MicroRNAs/genética
9.
Nat Commun ; 7: 10558, 2016 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-26822151

RESUMO

Metabolites derived from dietary choline and L-carnitine, such as trimethylamine N-oxide and betaine, have recently been identified as novel risk factors for atherosclerosis in mice and humans. We sought to identify genetic factors associated with plasma betaine levels and determine their effect on risk of coronary artery disease (CAD). A two-stage genome-wide association study (GWAS) identified two significantly associated loci on chromosomes 2q34 and 5q14.1. The lead variant on 2q24 (rs715) localizes to carbamoyl-phosphate synthase 1 (CPS1), which encodes a mitochondrial enzyme that catalyses the first committed reaction and rate-limiting step in the urea cycle. Rs715 is also significantly associated with decreased levels of urea cycle metabolites and increased plasma glycine levels. Notably, rs715 yield a strikingly significant and protective association with decreased risk of CAD in only women. These results suggest that glycine metabolism and/or the urea cycle represent potentially novel sex-specific mechanisms for the development of atherosclerosis.


Assuntos
Carbamoil-Fosfato Sintase (Amônia)/metabolismo , Doença das Coronárias/genética , Regulação Enzimológica da Expressão Gênica/fisiologia , Predisposição Genética para Doença , Betaína/sangue , Carbamoil-Fosfato Sintase (Amônia)/genética , Feminino , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Masculino , Metabolômica , Polimorfismo de Nucleotídeo Único , Fatores Sexuais
10.
Eur J Hum Genet ; 24(4): 587-91, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26220701

RESUMO

There is ongoing controversy as to whether obesity confers risk for CAD independently of associated risk factors including diabetes mellitus. We have carried out a Mendelian randomization study using a genetic risk score (GRS) for body mass index (BMI) based on 35 risk alleles to investigate this question in a population of 5831 early onset CAD cases without diabetes mellitus and 3832 elderly healthy control subjects, all of strictly European ancestry, with adjustment for traditional risk factors (TRFs). We then estimated the genetic correlation between these BMI and CAD (rg) by relating the pairwise genetic similarity matrix to a phenotypic covariance matrix between these two traits. GRSBMI significantly (P=2.12 × 10(-12)) associated with CAD status in a multivariate model adjusted for TRFs, with a per allele odds ratio (OR) of 1.06 (95% CI 1.042-1.076). The addition of GRSBMI to TRFs explained 0.75% of CAD variance and yielded a continuous net recombination index of 16.54% (95% CI=11.82-21.26%, P<0.0001). To test whether GRSBMI explained CAD status when adjusted for measured BMI, separate models were constructed in which the score and BMI were either included as covariates or not. The addition of BMI explained ~1.9% of CAD variance and GRSBMI plus BMI explained 2.65% of CAD variance. Finally, using bivariate restricted maximum likelihood analysis, we provide strong evidence of genome-wide pleiotropy between obesity and CAD. This analysis supports the hypothesis that obesity is a causal risk factor for CAD.


Assuntos
Doença da Artéria Coronariana/epidemiologia , Predisposição Genética para Doença , Obesidade/epidemiologia , Idoso , Índice de Massa Corporal , Estudos de Casos e Controles , Doença da Artéria Coronariana/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/genética
11.
Nat Commun ; 6: 8835, 2015 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-26617239

RESUMO

Despite its high prevalence and economic burden, the aetiology of human hypertension remains incompletely understood. Here we identify the transcription factor GATA5, as a new regulator of blood pressure (BP). GATA5 is expressed in microvascular endothelial cells and its genetic inactivation in mice (Gata5-null) leads to vascular endothelial dysfunction and hypertension. Endothelial-specific inactivation of Gata5 mimics the hypertensive phenotype of the Gata5-null mice, suggestive of an important role for GATA5 in endothelial homeostasis. Transcriptomic analysis of human microvascular endothelial cells with GATA5 knockdown reveals that GATA5 affects several genes and pathways critical for proper endothelial function, such as PKA and nitric oxide pathways. Consistent with a role in human hypertension, we report genetic association of variants at the GATA5 locus with hypertension traits in two large independent cohorts. Our results unveil an unsuspected link between GATA5 and a prominent human condition, and provide a new animal model for hypertension.


Assuntos
Pressão Sanguínea , Células Endoteliais/metabolismo , Fator de Transcrição GATA5/metabolismo , Hipertensão/metabolismo , Hipertensão/fisiopatologia , Animais , Modelos Animais de Doenças , Feminino , Fator de Transcrição GATA5/genética , Humanos , Hipertensão/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
12.
Circulation ; 132(21): 1969-78, 2015 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-26487755

RESUMO

BACKGROUND: The mechanism whereby the 9p21.3 locus confers risk for coronary artery disease remains incompletely understood. Risk alleles are associated with reduced expression of the cell cycle suppressor genes CDKN2A (p16 and p14) and CDKN2B (p15) and increased vascular smooth muscle cell proliferation. We asked whether risk alleles disrupt transcription factor binding to account for this effect. METHODS AND RESULTS: A bioinformatic screen was used to predict which of 59 single nucleotide polymorphisms at the 9p21.3 locus disrupt (or create) transcription factor binding sites. Electrophoretic mobility shift and luciferase reporter assays examined the binding and functionality of the predicted regulatory sequences. Primary human aortic smooth muscle cells (HAoSMCs) were genotyped for 9p21.3, and HAoSMCs homozygous for the risk allele showed reduced p15 and p16 levels and increased proliferation. rs10811656 and rs4977757 disrupted functional TEF-1 TEC1 AbaA domain (TEAD) transcription factor binding sites. TEAD3 and TEAD4 overexpression induced p16 in HAoSMCs homozygous for the nonrisk allele, but not for the risk allele. Transforming growth factor ß, known to activate p16 and also to interact with TEAD factors, failed to induce p16 or to inhibit proliferation of HAoSMCs homozygous for the risk allele. Knockdown of TEAD3 blocked transforming growth factor ß-induced p16 mRNA and protein expression, and dual knockdown of TEAD3 and TEAD4 markedly reduced p16 expression in heterozygous HAoSMCs. CONCLUSIONS: Here, we identify a novel mechanism whereby sequences at the 9p21.3 risk locus disrupt TEAD factor binding and TEAD3-dependent transforming growth factor ß induction of p16 in HAoSMCs. This mechanism accounts, in part, for the 9p21.3 coronary artery disease risk.


Assuntos
Cromossomos Humanos Par 9/genética , Doença das Coronárias/genética , Inibidor p16 de Quinase Dependente de Ciclina/biossíntese , Proteínas de Ligação a DNA/fisiologia , Proteínas Musculares/fisiologia , Polimorfismo de Nucleotídeo Único , Fatores de Transcrição/fisiologia , Fator de Crescimento Transformador beta/fisiologia , Adolescente , Adulto , Alelos , Aorta/citologia , Células Cultivadas , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Feminino , Técnicas de Silenciamento de Genes , Genes Reporter , Genes p16 , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Musculares/antagonistas & inibidores , Proteínas Musculares/biossíntese , Proteínas Musculares/genética , Músculo Liso Vascular/citologia , Proteínas Recombinantes/metabolismo , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Adulto Jovem
13.
Nat Genet ; 47(11): 1282-1293, 2015 11.
Artigo em Inglês | MEDLINE | ID: mdl-26390057

RESUMO

We carried out a trans-ancestry genome-wide association and replication study of blood pressure phenotypes among up to 320,251 individuals of East Asian, European and South Asian ancestry. We find genetic variants at 12 new loci to be associated with blood pressure (P = 3.9 × 10(-11) to 5.0 × 10(-21)). The sentinel blood pressure SNPs are enriched for association with DNA methylation at multiple nearby CpG sites, suggesting that, at some of the loci identified, DNA methylation may lie on the regulatory pathway linking sequence variation to blood pressure. The sentinel SNPs at the 12 new loci point to genes involved in vascular smooth muscle (IGFBP3, KCNK3, PDE3A and PRDM6) and renal (ARHGAP24, OSR1, SLC22A7 and TBX2) function. The new and known genetic variants predict increased left ventricular mass, circulating levels of NT-proBNP, and cardiovascular and all-cause mortality (P = 0.04 to 8.6 × 10(-6)). Our results provide new evidence for the role of DNA methylation in blood pressure regulation.


Assuntos
Pressão Sanguínea/genética , Metilação de DNA , Loci Gênicos/genética , Estudo de Associação Genômica Ampla/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Grupo com Ancestrais do Continente Asiático/genética , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/etnologia , Doenças Cardiovasculares/genética , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Predisposição Genética para Doença/etnologia , Predisposição Genética para Doença/genética , Variação Genética , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Peptídeo Natriurético Encefálico/sangue , Fragmentos de Peptídeos/sangue , Polimorfismo de Nucleotídeo Único , Análise de Regressão , Fatores de Risco
14.
Circ Res ; 117(8): 671-83, 2015 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-26195219

RESUMO

RATIONALE: Inflammation impairs macrophage cholesterol clearance from vascular tissues and promotes atherosclerosis. Inflammatory macrophages suppress expression of the transcription cofactor interferon regulatory factor 2-binding protein 2 (IRF2BP2), and genetic variants near IRF2BP2 associate with ischemic heart disease progression in humans. OBJECTIVES: To test whether IRF2BP2 in macrophages affects atherosclerosis in mice and humans. METHODS AND RESULTS: We generated mice that delete IRF2BP2 in macrophages. IRF2BP2-deficient macrophages worsened atherosclerosis in irradiated low-density lipoprotein receptor null-recipient mice and in apolipoprotein E null mice. IRF2BP2-deficient macrophages were inflammatory and had impaired cholesterol efflux because of their inability to activate the cholesterol transporter ABCA1 in response to cholesterol loading. Their expression of the anti-inflammatory transcription factor Krüppel-like factor 2 was markedly reduced. Promoter studies revealed that IRF2BP2 is required for MEF2-dependent activation of Krüppel-like factor 2. Importantly, restoring Krüppel-like factor 2 in IRF2BP2-deficient macrophages attenuated M1 inflammatory and rescued M2 anti-inflammatory gene activation and improved the cholesterol efflux deficit by restoring ABCA1 activation in response to cholesterol loading. In a cohort of 1066 angiographic cases and 1011 controls, homozygous carriers of a deletion polymorphism (rs3045215) in the 3' untranslated region sequence of human IRF2BP2 mRNA had a higher risk of coronary artery disease (recessive model, odds ratio [95% confidence interval]=1.560 [1.179-2.065], P=1.73E-03) and had lower IRF2BP2 (and Krüppel-like factor 2) protein levels in peripheral blood mononuclear cells. The effect of this deletion polymorphism to suppress protein expression was confirmed in luciferase reporter studies. CONCLUSION: Ablation of IRF2BP2 in macrophages worsens atherosclerosis in mice, and a deletion variant that lowers IRF2BP2 expression predisposes to coronary artery disease in humans.


Assuntos
Aterosclerose/prevenção & controle , Proteínas de Transporte/metabolismo , Colesterol/metabolismo , Doença da Artéria Coronariana/prevenção & controle , Inflamação/prevenção & controle , Ativação de Macrófagos , Macrófagos/metabolismo , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Regiões 3' não Traduzidas , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Idoso , Idoso de 80 Anos ou mais , Animais , Apolipoproteínas E/deficiência , Apolipoproteínas E/genética , Aterosclerose/genética , Aterosclerose/metabolismo , Proteínas de Transporte/genética , Estudos de Casos e Controles , Células Cultivadas , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/genética , Doença da Artéria Coronariana/metabolismo , Modelos Animais de Doenças , Feminino , Predisposição Genética para Doença , Homozigoto , Humanos , Inflamação/genética , Inflamação/metabolismo , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Fatores de Transcrição MEF2/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Proteínas Nucleares/genética , Razão de Chances , Fenótipo , Polimorfismo Genético , Regiões Promotoras Genéticas , Fatores de Proteção , Radiografia , Receptores de LDL/deficiência , Receptores de LDL/genética , Fatores de Risco , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Transfecção
15.
Circ Cardiovasc Genet ; 8(4): 618-27, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26043746

RESUMO

BACKGROUND: Statins lower low-density lipoprotein cholesterol (LDL-C) and risk of coronary artery disease (CAD), but they may be ineffective or not tolerated. Bile acid sequestrants (BAS) reduce LDL-C, yet their clinical efficacy on CAD remains controversial. METHODS AND RESULTS: We conducted a systematic review and meta-analysis of randomized controlled trials to assess the effect of cholestyramine and colesevelam. We then used Mendelian randomization to estimate the effect of BAS on reducing the risk of CAD. First, we quantified the effect of rs4299376 (ABCG5/ABCG8), which affects the intestinal cholesterol absorption pathway targeted by BAS and then we used these estimates to predict the effect of BAS on CAD. Nineteen randomized controlled trials with a total of 7021 study participants were included. Cholestyramine 24 g/d was associated with a reduction in LDL-C of 23.5 mg/dL (95% confidence interval [CI] -26.8,-20.2; N=3806) and a trend toward reduced risk of CAD (odds ratio 0.81, 95% CI 0.70-1.02; P=0.07; N=3806), whereas colesevelam 3.75 g/d was associated with a reduction in LDL-C of 22.7 mg/dL (95% CI -28.3, -17.2; N=759). Based on the findings that rs4299376 was associated with a 2.75 mg/dL decrease in LDL-C and a 5% decrease in risk of CAD outcomes, we estimated that cholestyramine was associated with an odds ratio for CAD of 0.63 (95% CI 0.52-0.77; P=6.3×10(-6)) and colesevelam with an odds ratio of 0.64 (95% CI 0.52-0.79, P=4.3×10(-5)), which were not statistically different from BAS clinical trials (P>0.05). CONCLUSIONS: The cholesterol lowering effect of BAS may translate into a clinically relevant reduction in CAD.


Assuntos
Anticolesterolemiantes/uso terapêutico , Ácidos e Sais Biliares/metabolismo , Resina de Colestiramina/uso terapêutico , Cloridrato de Colesevelam/uso terapêutico , Doença da Artéria Coronariana/tratamento farmacológico , Membro 5 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Membro 8 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Anticolesterolemiantes/metabolismo , LDL-Colesterol/antagonistas & inibidores , LDL-Colesterol/metabolismo , Resina de Colestiramina/metabolismo , Cloridrato de Colesevelam/metabolismo , Doença da Artéria Coronariana/genética , Doença da Artéria Coronariana/metabolismo , Humanos , Lipoproteínas/genética , Lipoproteínas/metabolismo , Análise da Randomização Mendeliana/métodos , Polimorfismo de Nucleotídeo Único , Ensaios Clínicos Controlados Aleatórios como Assunto
16.
Arterioscler Thromb Vasc Biol ; 35(7): 1712-22, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25977570

RESUMO

OBJECTIVE: Genome-wide association studies have identified multiple genetic variants affecting the risk of coronary artery disease (CAD). However, individually these explain only a small fraction of the heritability of CAD and for most, the causal biological mechanisms remain unclear. We sought to obtain further insights into potential causal processes of CAD by integrating large-scale GWA data with expertly curated databases of core human pathways and functional networks. APPROACHES AND RESULTS: Using pathways (gene sets) from Reactome, we carried out a 2-stage gene set enrichment analysis strategy. From a meta-analyzed discovery cohort of 7 CAD genome-wide association study data sets (9889 cases/11 089 controls), nominally significant gene sets were tested for replication in a meta-analysis of 9 additional studies (15 502 cases/55 730 controls) from the Coronary ARtery DIsease Genome wide Replication and Meta-analysis (CARDIoGRAM) Consortium. A total of 32 of 639 Reactome pathways tested showed convincing association with CAD (replication P<0.05). These pathways resided in 9 of 21 core biological processes represented in Reactome, and included pathways relevant to extracellular matrix (ECM) integrity, innate immunity, axon guidance, and signaling by PDRF (platelet-derived growth factor), NOTCH, and the transforming growth factor-ß/SMAD receptor complex. Many of these pathways had strengths of association comparable to those observed in lipid transport pathways. Network analysis of unique genes within the replicated pathways further revealed several interconnected functional and topologically interacting modules representing novel associations (eg, semaphoring-regulated axonal guidance pathway) besides confirming known processes (lipid metabolism). The connectivity in the observed networks was statistically significant compared with random networks (P<0.001). Network centrality analysis (degree and betweenness) further identified genes (eg, NCAM1, FYN, FURIN, etc) likely to play critical roles in the maintenance and functioning of several of the replicated pathways. CONCLUSIONS: These findings provide novel insights into how genetic variation, interpreted in the context of biological processes and functional interactions among genes, may help define the genetic architecture of CAD.


Assuntos
Doença da Artéria Coronariana/genética , Estudo de Associação Genômica Ampla , Doença da Artéria Coronariana/metabolismo , Humanos
17.
J Am Heart Assoc ; 4(3): e001544, 2015 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-25762803

RESUMO

BACKGROUND: Brain-derived neurotrophic factor (BDNF) is a pleiotropic peptide involved in maintaining endothelial integrity. It is unknown if circulating BDNF levels are associated with risk of cardiovascular disease (CVD). METHODS AND RESULTS: We prospectively investigated the association of circulating BDNF levels with cardiovascular events and mortality in 3687 participants (mean age 65 years, 2068 women) from the Framingham Heart Study (FHS). Using a common nonsynonomous single nucleotide polymorphism (SNP) in the BDNF gene (rs6265), we then performed a Mendelian randomization experiment in the CARDIoGRAM (Coronary ARtery DIsease Genome-Wide Replication And Meta-Analysis) consortium (>22,000 coronary artery disease [CAD] cases, >60,000 controls) to investigate whether SNP rs6265 was associated with CAD in CARDIoGRAM and, if so, whether the effect estimate differed from that predicted based on FHS data. On follow-up (median 8.9 years), 467 individuals (261 women) in FHS experienced a CVD event, and 835 (430 women) died. In multivariable-adjusted Cox regression, serum BDNF was associated inversely with CVD risk (hazard ratio [HR] per 1-SD increase 0.88, 95% CI 0.80 to 0.97, P=0.01) and with mortality (HR 0.87, 95% CI 0.80 to 0.93, P=0.0002). SNP rs6265 was associated with BDNF concentrations (0.772 ng/mL increase per minor allele copy) in FHS. In CARDIoGRAM, SNP rs6265 was associated with CAD (odds ratio 0.957, 95% CI 0.923 to 0.992), a magnitude consistent with the predicted effect (HR per minor allele copy 0.99, 95% CI 0.98 to 1.0; P=0.06 for difference between predicted and observed effect). CONCLUSION: Higher serum BDNF is associated with a decreased risk of CVD and mortality. Mendelian randomization suggests a causal protective role of BDNF in the pathogenesis of CVD.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/sangue , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/epidemiologia , Idoso , Biomarcadores/sangue , Fator Neurotrófico Derivado do Encéfalo/genética , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/genética , Doenças Cardiovasculares/mortalidade , Estudos de Casos e Controles , Feminino , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Incidência , Modelos Lineares , Masculino , Massachusetts/epidemiologia , Pessoa de Meia-Idade , Análise Multivariada , Fenótipo , Polimorfismo de Nucleotídeo Único , Valor Preditivo dos Testes , Prognóstico , Modelos de Riscos Proporcionais , Estudos Prospectivos , Fatores de Proteção , Medição de Risco , Fatores de Risco , Fatores de Tempo , Regulação para Cima
18.
Neuron ; 85(6): 1319-31, 2015 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-25754825

RESUMO

Collapse of endocannabinoid (eCB) signaling in the amygdala contributes to stress-induced anxiety, but the mechanisms of this effect remain unclear. eCB production is tied to the function of the glutamate receptor mGluR5, itself dependent on tyrosine phosphorylation. Herein, we identify a novel pathway linking eCB regulation of anxiety through phosphorylation of mGluR5. Mice lacking LMO4, an endogenous inhibitor of the tyrosine phosphatase PTP1B, display reduced mGluR5 phosphorylation, eCB signaling, and profound anxiety that is reversed by genetic or pharmacological suppression of amygdalar PTP1B. Chronically stressed mice exhibited elevated plasma corticosterone, decreased LMO4 palmitoylation, elevated PTP1B activity, reduced amygdalar eCB levels, and anxiety behaviors that were restored by PTP1B inhibition or by glucocorticoid receptor antagonism. Consistently, corticosterone decreased palmitoylation of LMO4 and its inhibition of PTP1B in neuronal cells. Collectively, these data reveal a stress-responsive corticosterone-LMO4-PTP1B-mGluR5 cascade that impairs amygdalar eCB signaling and contributes to the development of anxiety.


Assuntos
Tonsila do Cerebelo/metabolismo , Ansiedade/metabolismo , Endocanabinoides/metabolismo , Transdução de Sinais , Estresse Psicológico/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Ansiedade/genética , Moduladores de Receptores de Canabinoides , Citoplasma/metabolismo , Espaço Intracelular/metabolismo , Proteínas com Domínio LIM/genética , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Receptor CB1 de Canabinoide/metabolismo , Transdução de Sinais/fisiologia
19.
Biochem Biophys Res Commun ; 458(1): 21-7, 2015 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-25623533

RESUMO

Protein tyrosine phosphatase 1B (PTP1B) inhibits insulin signaling, interfering with its control of glucose homeostasis and metabolism. PTP1B activity is elevated in obesity and type 2 diabetes and is a major cause of insulin resistance. Trodusquemine (MSI-1436) is a "first-in-class" highly selective inhibitor of PTP1B that can cross the blood-brain barrier to suppress feeding and promote insulin sensitivity and glycemic control. Trodusquemine is a naturally occurring cholestane that can be purified from the liver of the dogfish shark, Squalus acanthias, but it can also be manufactured synthetically by a fairly laborious process that requires several weeks. Here, we tested a novel easily and rapidly (2 days) synthesized polyaminosteroid derivative (Claramine) containing a spermino group similar to Trodusquemine for its ability to inhibit PTP1B. Like Trodusquemine, Claramine displayed selective inhibition of PTP1B but not its closest related phosphatase TC-PTP. In cultured neuronal cells, Claramine and Trodusquemine both activated key components of insulin signaling, with increased phosphorylation of insulin receptor-ß (IRß), Akt and GSK3ß. Intraperitoneal administration of Claramine or Trodusquemine effectively restored glycemic control in diabetic mice as determined by glucose and insulin tolerance tests. A single intraperitoneal dose of Claramine, like an equivalent dose of Trodusquemine, suppressed feeding and caused weight loss without increasing energy expenditure. In summary, Claramine is an alternative more easily manufactured compound for the treatment of type II diabetes.


Assuntos
Colestanos/farmacologia , Diabetes Mellitus Experimental/tratamento farmacológico , Insulina/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 1/antagonistas & inibidores , Espermina/análogos & derivados , Animais , Células Cultivadas/efeitos dos fármacos , Colestanos/síntese química , Colestanos/química , Diabetes Mellitus Experimental/metabolismo , Ingestão de Alimentos/efeitos dos fármacos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Insulina/farmacologia , Masculino , Camundongos , Camundongos Mutantes , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 1/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 2/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptor de Insulina/metabolismo , Espermina/síntese química , Espermina/química , Espermina/farmacologia , Perda de Peso/efeitos dos fármacos
20.
Neurol Genet ; 1(1): e10, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27066539

RESUMO

OBJECTIVE: To apply genetic analysis of genome-wide association data to study the extent and nature of a shared biological basis between migraine and coronary artery disease (CAD). METHODS: Four separate methods for cross-phenotype genetic analysis were applied on data from 2 large-scale genome-wide association studies of migraine (19,981 cases, 56,667 controls) and CAD (21,076 cases, 63,014 controls). The first 2 methods quantified the extent of overlapping risk variants and assessed the load of CAD risk loci in migraineurs. Genomic regions of shared risk were then identified by analysis of covariance patterns between the 2 phenotypes and by querying known genome-wide significant loci. RESULTS: We found a significant overlap of genetic risk loci for migraine and CAD. When stratified by migraine subtype, this was limited to migraine without aura, and the overlap was protective in that patients with migraine had a lower load of CAD risk alleles than controls. Genes indicated by 16 shared risk loci point to mechanisms with potential roles in migraine pathogenesis and CAD, including endothelial dysfunction (PHACTR1) and insulin homeostasis (GIP). CONCLUSIONS: The results suggest that shared biological processes contribute to risk of migraine and CAD, but surprisingly this commonality is restricted to migraine without aura and the impact is in opposite directions. Understanding the mechanisms underlying these processes and their opposite relationship to migraine and CAD may improve our understanding of both disorders.

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