RESUMO
BACKGROUND: Chronic Chagas Cardiomyopathy (CCC) usually develops between 10 and 20 years after the first parasitic infection and is one of the leading causes of end-stage heart failure in Latin America. Despite the great inter-individual variability in CCC susceptibility (only 30% of infected individuals ever present CCC), there are no known predictors for disease development in those chronically infected. METHODOLOGY/PRINCIPAL FINDINGS: We describe a new susceptibility locus for CCC through a GWAS analysis in the SaMi-Trop cohort, a population-based study conducted in a Chagas endemic region from Brazil. This locus was also associated with CCC in the REDS II Study. The newly identified locus (rs34238187, OR 0.73, p-value 2.03 x 10-9) spans a haplotype of approximately 30Kb on chromosome 18 (chr18: 5028302-5057621) and is also associated with 80 different traits, most of them blood protein traits significantly enriched for immune-related biological pathways. Hi-C data show that the newly associated locus is able to interact with chromatin sites as far as 10Mb on chromosome 18 in a number of different cell types and tissues. Finally, we were able to confirm, at the tissue transcriptional level, the immune-associated blood protein signature using a multi-tissue differential gene expression and enrichment analysis. CONCLUSIONS/SIGNIFICANCE: We suggest that the newly identified locus impacts CCC risk among T cruzi infected individuals through the modulation of a downstream transcriptional and protein signature associated with host-parasite immune response. Functional characterization of the novel risk locus is warranted.
Assuntos
Cardiomiopatia Chagásica , Doença de Chagas , Trypanosoma cruzi , Cromatina , Cromossomos Humanos Par 18/genética , Cromossomos Humanos Par 18/metabolismo , Estudo de Associação Genômica Ampla , Humanos , Trypanosoma cruzi/fisiologiaRESUMO
Endothelial dysfunction (ED) is a hallmark of atherosclerosis and is influenced by well-defined risk factors, including hypoxia, dyslipidemia, inflammation, and oscillatory flow. However, the individual and combined contributions to the molecular underpinnings of ED remain elusive. We used global gene expression in human coronary artery endothelial cells to identify gene pathways and cellular processes in response to chemical hypoxia, oxidized lipids, IL-1ß induced inflammation, oscillatory flow, and these combined stimuli. We found that clustering of the surrogate risk factors differed from the sum of the individual insults that gave rise to emergent phenotypes such as cell proliferation. We validated these observations in samples of human coronary artery atherosclerotic plaques analyzed using single-cell RNA sequencing. Our findings suggest a hierarchical interaction between surrogates of CV risk factors and the advent of emergent phenotypes in response to combined stimulation in endothelial cells that may influence ED.
Assuntos
Biomarcadores/sangue , Doenças Cardiovasculares/metabolismo , Doenças Cardiovasculares/patologia , Linhagem Celular , Células Endoteliais , Fatores de Risco de Doenças Cardíacas , HumanosRESUMO
Human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) resemble fetal cardiomyocytes and electrical stimulation (ES) has been explored to mature the differentiated cells. Here, we hypothesize that ES applied at the beginning of the differentiation process, triggers both differentiation of the hiPSC-CMs into a specialized conduction system (CS) phenotype and cell maturation. We applied ES for 15 days starting on day 0 of the differentiation process and found an increased expression of transcription factors and proteins associated with the development and function of CS including Irx3, Nkx2.5 and contactin 2, Hcn4 and Scn5a, respectively. We also found activation of intercalated disc proteins (Nrap and ß-catenin). We detected ES-induced CM maturation as indicated by increased Tnni1 and Tnni3 expression. Confocal micrographs showed a shift towards expression of the gap junction protein connexin 40 in ES hiPSC-CM compared to the more dominant expression of connexin 43 in controls. Finally, analysis of functional parameters revealed that ES hiPSC-CMs exhibited faster action potential (AP) depolarization, longer intracellular Ca2+ transients, and slower AP duration at 90% of repolarization, resembling fast conducting fibers. Altogether, we provided evidence that ES during the differentiation of hiPSC to cardiomyocytes lead to development of cardiac conduction-like cells with more mature cytoarchitecture. Thus, hiPSC-CMs exposed to ES during differentiation can be instrumental to develop CS cells for cardiac disease modelling, screening individual drugs on a precison medicine type platform and support the development of novel therapeutics for arrhythmias.
Assuntos
Potenciais de Ação/fisiologia , Cálcio/metabolismo , Células-Tronco Pluripotentes Induzidas/fisiologia , Miócitos Cardíacos/fisiologia , Biomarcadores/metabolismo , Diferenciação Celular , Terapia Baseada em Transplante de Células e Tecidos/métodos , Conexinas/genética , Conexinas/metabolismo , Contactina 2/genética , Contactina 2/metabolismo , Estimulação Elétrica , Expressão Gênica , Sistema de Condução Cardíaco/citologia , Sistema de Condução Cardíaco/fisiologia , Proteína Homeobox Nkx-2.5/genética , Proteína Homeobox Nkx-2.5/metabolismo , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/genética , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/metabolismo , Células-Tronco Pluripotentes Induzidas/citologia , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Miócitos Cardíacos/citologia , Canal de Sódio Disparado por Voltagem NAV1.5/genética , Canal de Sódio Disparado por Voltagem NAV1.5/metabolismo , Canais de Potássio/genética , Canais de Potássio/metabolismo , Cultura Primária de Células , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Troponina I/genética , Troponina I/metabolismo , beta Catenina/genética , beta Catenina/metabolismo , Proteína alfa-5 de Junções ComunicantesRESUMO
Aldosterone antagonists slow the progression of chronic kidney disease (CKD), but their use is limited by hyperkalemia, especially when associated with RAS inhibitors. We examined the renoprotective effects of Ly, a novel non-steroidal mineralocorticoid receptor (MR) blocker, through two experimental protocols: In Protocol 1, male Munich-Wistar rats underwent 5/6 renal ablation (Nx), being divided into: Nx+V, receiving vehicle, Nx+Eple, given eplerenone, 150 mg/kg/day, and Nx+Ly, given Ly, 20 mg/kg/day. A group of untreated sham-operated rats was also studied. Ly markedly raised plasma renin activity (PRA) and aldosterone, and exerted more effective anti-albuminuric and renoprotective action than eplerenone. In Protocol 2, Nx rats remained untreated until Day 60, when they were divided into: Nx+V receiving vehicle; Nx+L treated with losartan, 50 mg/kg/day; Nx+L+Eple, given losartan and eplerenone, and Nx+L+Ly, given losartan and Ly. Treatments lasted for 90 days. As an add-on to losartan, Ly normalized blood pressure and albuminuria, and prevented CKD progression more effectively than eplerenone. This effect was associated with strong stimulation of PRA and aldosterone. Despite exhibiting higher affinity for the MR than either eplerenone or spironolactone, Ly caused no hyperkalemia. Ly may become a novel asset in the effort to detain the progression of CKD.
Assuntos
Antagonistas de Receptores de Mineralocorticoides/administração & dosagem , Insuficiência Renal Crônica/tratamento farmacológico , Albuminúria/prevenção & controle , Aldosterona/sangue , Animais , Pressão Sanguínea , Eplerenona/administração & dosagem , Losartan/administração & dosagem , Nefrectomia , Ratos Wistar , Renina/sangue , Resultado do TratamentoRESUMO
Cumulative epidemiological evidence indicates that the presence of microalbuminuria predicts a higher frequency of cardiovascular events, peripheral disease, and mortality in essential hypertension. Microalbuminuria may arise from increased glomerular permeability and/or reduced proximal tubular reabsorption of albumin by receptor-mediated endocytosis. This study aimed to evaluate the temporal pattern of urinary protein excretion and to test the hypothesis that progression of microalbuminuria is associated with decreased protein expression of critical components of the endocytic apparatus in the renal proximal tubule of spontaneously hypertensive rats (SHR). We found that urinary albumin excretion increased progressively with blood pressure in SHR from 6 to 21 wk of age. In addition, SDS-PAGE analysis of urinary proteins showed that microalbuminuric SHR virtually excreted proteins of the size of albumin or smaller (<70 kDa), typical of tubular proteinuria. Moreover, the protein abundance of the endocytic receptors megalin and cubilin as well as of the chloride channel ClC-5 progressively decreased in the renal cortex of SHR from 6 to 21 wk of age. Expression of the vacuolar Hâº-ATPase B2 subunit was also reduced in the renal cortex of 21-wk-old compared with both 6- and 14-wk-old SHR. Collectively, our study suggests that enhanced urinary protein excretion, especially of albumin, may be due, at least in part, to lower expression of key components of the apical endocytic apparatus in the renal proximal tubule. Finally, one may speculate that dysfunction of the apical endocytic pathway in the renal proximal tubule may contribute to the development of microalbuminuria in essential hypertension.
Assuntos
Albuminúria/metabolismo , Endocitose , Hipertensão/metabolismo , Túbulos Renais Proximais/metabolismo , Albuminúria/patologia , Albuminúria/fisiopatologia , Animais , Pressão Sanguínea , Progressão da Doença , Hipertensão/patologia , Hipertensão/fisiopatologia , Túbulos Renais Proximais/patologia , Túbulos Renais Proximais/fisiopatologia , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Masculino , Ratos , Ratos Endogâmicos SHR , Ratos Wistar , Receptores de Superfície Celular/metabolismo , Transferrina/metabolismoRESUMO
The single nucleotide polymorphism (SNP) within the TCF7L2 gene, rs7903146, is, to date, the most significant genetic marker associated with Type 2 diabetes mellitus (T2DM) risk. Nonetheless, its functional role in disease pathology is poorly understood. The aim of the present study was to investigate, in vascular smooth muscle cells from 92 patients undergoing aortocoronary bypass surgery, the contribution of this SNP in T2DM using expression levels and expression correlation comparison approaches, which were visually represented as gene interaction networks. Initially, the expression levels of 41 genes (seven TCF7L2 splice forms and 40 other T2DM relevant genes) were compared between rs7903146 wild-type (CC) and T2DM-risk (CT + TT) genotype groups. Next, we compared the expression correlation patterns of these 41 genes between groups to observe if the relationships between genes were different. Five TCF7L2 splice forms and nine genes showed significant expression differences between groups. RXRα gene was pinpointed as showing the most different expression correlation pattern with other genes. Therefore, T2DM risk alleles appear to be influencing TCF7L2 splice form's expression in vascular smooth muscle cells, and RXRα gene is pointed out as a treatment target candidate for risk reduction in individuals with high risk of developing T2DM, especially individuals harboring TCF7L2 risk genotypes.
Assuntos
Doenças Cardiovasculares/genética , Diabetes Mellitus Tipo 2/genética , Redes Reguladoras de Genes/genética , Receptor X Retinoide alfa/genética , Proteína 2 Semelhante ao Fator 7 de Transcrição/genética , Brasil , Doenças Cardiovasculares/cirurgia , Ponte de Artéria Coronária , Primers do DNA/genética , Genótipo , Humanos , Músculo Liso Vascular/metabolismo , Polimorfismo de Nucleotídeo Único/genética , Isoformas de Proteínas/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de RiscoRESUMO
NADPH oxidase p22phox subunit is responsible for the production of reactive oxygen species in the vascular tissue. The C242T polymorphism in the p22phox gene has been associated with diverse coronary artery disease phenotypes, but the findings about the protective or harmful effects of the T allele are still controversial. Our main aim was to assess the effect of p22phox C242T genotypes on arterial stiffness, a predictor of late morbidity and mortality, in individuals from the general population. We randomly selected 1,178 individuals from the general population of Vitoria City, Brazil. Genotypes for the C242T polymorphism were detected by PCR-RFLP, and pulse wave velocity (PWV) values were measured with a noninvasive automatic device Complior. p22phox and TNF-α gene expression were quantified by real-time PCR in human arterial mammary smooth muscle cells. In both the entire and nonhypertensive groups: individuals carrying the TT genotype had higher PWV values and higher risk for increased arterial stiffness [odds ratio (OR) 1.93, 95% confidence interval (CI) 1.27-2.92 and OR 1.78, 95% CI 1.07-2.95, respectively] compared with individuals carrying CC+CT genotypes, even after adjustment for covariates. No difference in the p22phox gene expression according C242T genotypes was observed. However, TNF-α gene expression was higher in cells from individual carrying the T allele, suggesting that this genetic marker is associated with functional phenotypes at the gene expression level. In conclusion, we suggest that p22phox C242T polymorphism is associated with arterial stiffness evaluated by PWV in the general population. This genetic association shed light on the understanding of the genetic modulation on vascular dysfunction mediated by NADPH oxidase.
Assuntos
NADPH Oxidases/genética , Polimorfismo Genético , Fator de Necrose Tumoral alfa/genética , Rigidez Vascular/genética , Adulto , Artérias/metabolismo , Artérias/patologia , Artérias/fisiopatologia , Pressão Sanguínea , Brasil , Células Cultivadas , Estudos Transversais , Feminino , Expressão Gênica , Frequência do Gene , Genótipo , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Fluxo Pulsátil , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
OBJECTIVE: To investigate the relationship between TXNIP polymorphisms, diabetes and hypertension phenotypes in the Brazilian general population. METHODS: Five hundred seventy-six individuals randomly selected from the general urban population according to the MONICA-WHO project guidelines were phenotyped for cardiovascular risk factors. A second, independent, sample composed of 487 family-trios from a different site was also selected. Nine TXNIP polymorphisms were studied. The potential association between TXNIP variability and glucose-phenotypes in children was also explored. TXNIP expression was quantified by real-time PCR in 53 samples from human smooth muscle cells primary culture. RESULTS: TXNIP rs7211 and rs7212 polymorphisms were significantly associated with glucose and blood pressure related phenotypes. In multivariate logistic regression models the studied markers remained associated with diabetes even after adjustment for covariates. TXNIP rs7211 T/rs7212 G haplotype (present in approximately 17% of individuals) was significantly associated to diabetes in both samples. In children, the TXNIP rs7211 T/rs7212 G haplotype was associated with fasting insulin concentrations. Finally, cells harboring TXNIP rs7212 G allele presented higher TXNIP expression levels compared with carriers of TXNIP rs7212 CC genotype (p=0.02). CONCLUSION: Carriers of TXNIP genetic variants presented higher TXNIP expression, early signs of glucose homeostasis derangement and increased susceptibility to chronic metabolic conditions such as diabetes and hypertension. Our data suggest that genetic variation in the TXNIP gene may act as a "common ground" modulator of both traits: diabetes and hypertension.
Assuntos
Proteínas de Transporte/genética , Diabetes Mellitus/genética , Variação Genética , Hipertensão/genética , Adulto , Glicemia/análise , Pressão Sanguínea/genética , Brasil , Proteínas de Transporte/metabolismo , Células Cultivadas , Distribuição de Qui-Quadrado , Estudos Transversais , Diabetes Mellitus/sangue , Diabetes Mellitus/metabolismo , Feminino , Predisposição Genética para Doença , Haplótipos , Homeostase , Humanos , Hipertensão/metabolismo , Hipertensão/fisiopatologia , Insulina/sangue , Modelos Lineares , Desequilíbrio de Ligação , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Fenótipo , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Medição de Risco , Fatores de RiscoRESUMO
Suppression of the renin-angiotensin system (RAS) during murine lactation causes progressive renal injury, indicating a physiological action of angiotensin II on nephrogenesis. The nuclear factor NF-κB system is one of the main intracellular mediators of angiotensin II. We investigated whether inhibition of this system with pyrrolidine dithiocarbamate (PDTC) during rat nephrogenesis would lead to similar hypertension and renal injury as observed with RAS suppressors. Immediately after delivery, 32 Munich-Wistar dams, each nursing 6 male pups, were divided into 2 groups: C, untreated, and PDTC, receiving PDTC, 280 mg kg(-1) day(-1) orally, during 21 days. After weaning, the offspring were followed until 10 months of age without treatment. Adult rats that received neonatal PDTC exhibited stable hypertension and myocardial injury, without albuminuria. To gain additional insight into this process, the renal expression of RAS components and sodium transporters were determined by quantitative real-time PCR (qRT-PCR) at 3 and 10 months of life. Renal renin and angiotensinogen were upregulated at 3 and downregulated at 10 months of age, suggesting a role for early local RAS activation. Likewise, there was early upregulation of the proximal sodium/glucose and sodium/bicarbonate transporters, which abated later in life, suggesting that additional factors sustained hypertension in the long run. The conclusions drawn from the findings were as follows: (1) an intact NF-κB system during nephrogenesis may be essential to normal renal and cardiovascular function in adult life; (2) neonatal PDTC represents a new model of hypertension, lacking overt structural injury or functional impairment of the kidneys; and (3) hypertension in this model seems associated with early temporary activation of renal RAS and sodium transporters.
Assuntos
Hipertensão/etiologia , Rim/crescimento & desenvolvimento , NF-kappa B/fisiologia , Animais , Feminino , Masculino , NF-kappa B/antagonistas & inibidores , Prolina/análogos & derivados , Prolina/farmacologia , Ratos , Sistema Renina-Angiotensina/fisiologia , Sódio/metabolismo , Tiocarbamatos/farmacologiaRESUMO
RATIONALE: Major coronary vessels derive from the proepicardium, the cellular progenitor of the epicardium, coronary endothelium, and coronary smooth muscle cells (CoSMCs). CoSMCs are delayed in their differentiation relative to coronary endothelial cells (CoEs), such that CoSMCs mature only after CoEs have assembled into tubes. The mechanisms underlying this sequential CoE/CoSMC differentiation are unknown. Retinoic acid (RA) is crucial for vascular development and the main RA-synthesizing enzyme is progressively lost from epicardially derived cells as they differentiate into blood vessel types. In parallel, myocardial vascular endothelial growth factor (VEGF) expression also decreases along coronary vessel muscularization. OBJECTIVE: We hypothesized that RA and VEGF act coordinately as physiological brakes to CoSMC differentiation. METHODS AND RESULTS: In vitro assays (proepicardial cultures, cocultures, and RALDH2 [retinaldehyde dehydrogenase-2]/VEGF adenoviral overexpression) and in vivo inhibition of RA synthesis show that RA and VEGF act as repressors of CoSMC differentiation, whereas VEGF biases epicardially derived cell differentiation toward the endothelial phenotype. CONCLUSION: Experiments support a model in which early high levels of RA and VEGF prevent CoSMC differentiation from epicardially derived cells before RA and VEGF levels decline as an extensive endothelial network is established. We suggest this physiological delay guarantees the formation of a complex, hierarchical, tree of coronary vessels.
Assuntos
Diferenciação Celular , Vasos Coronários/metabolismo , Células Endoteliais/metabolismo , Miócitos de Músculo Liso/metabolismo , Pericárdio/metabolismo , Transdução de Sinais , Tretinoína/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Aldeído Oxirredutases/genética , Aldeído Oxirredutases/metabolismo , Animais , Apoptose , Comunicação Autócrina , Diferenciação Celular/genética , Células Cultivadas , Embrião de Galinha , Técnicas de Cocultura , Vasos Coronários/embriologia , Fibroblastos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Camundongos , Morfogênese , Miócitos Cardíacos/metabolismo , Comunicação Parácrina , Pericárdio/embriologia , Codorniz , Ratos , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais/genética , Técnicas de Cultura de Tecidos , Transdução Genética , Fator A de Crescimento do Endotélio Vascular/genéticaRESUMO
OBJECTIVE: Null genotypes of glutathione S-transferase (GSTs) exhibit absence of enzymatic activity and are hypothesized to modulate an increased risk of developing cardiovascular disease. The aim of this study was to identify the potential association between GSTM1 and GSTT1 deleted polymorphisms with cardiovascular risk factors and coronary atherosclerosis in two independent urban populations. METHODS AND RESULTS: Genotype distribution of GSTM1 and GSTT1 deleted polymorphism were examined in a sample of 1577 individuals from the general population and a replication sample of 871 individuals submitted to coronary angiography. Triglycerides, HDL-cholesterol and the triglycerides/HDL ratio were significantly associated with a double-deleted genotype in individuals from the general population. These findings were replicated in a second, independent, population of individuals submitted to coronary angiography. In addition, coronary artery disease severity was also associated with GSTs genotypes and the risk conferred from GSTs genotype was mainly due to triglycerides/HDL ratio information. CONCLUSIONS: The data suggest that the presence of a double deletion genotypes of the GSTM1 and GSTT1 genes is associated with hypertriglyceridemia and low HDL-cholesterol levels in humans. These novel findings may provide a new unexplored link between lipid metabolism and GST homeostasis.
Assuntos
HDL-Colesterol/genética , Doença da Artéria Coronariana/genética , Deleção de Genes , Glutationa Transferase/genética , HDL-Colesterol/sangue , Doença da Artéria Coronariana/etiologia , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Polimorfismo Genético , Fatores de Risco , Triglicerídeos/sangueRESUMO
To dissect the genetic architecture controlling blood pressure (BP) regulation in the spontaneously hypertensive rat (SHR) we derived congenic rat strains for four previously mapped BP quantitative trait loci (QTLs) in chromosomes 2, 4, and 16. Target chromosomal regions from the Brown Norway rat (BN) averaging 13-29 cM were introgressed by marker-assisted breeding onto the SHR genome in 12 or 13 generations. Under normal salt intake, QTLs on chromosomes 2a, 2c, and 4 were associated with significant changes in systolic BP (13, 20, and 15 mmHg, respectively), whereas the QTL on chromosome 16 had no measurable effect. On high salt intake (1% NaCl in drinking water for 2 wk), the chromosome 16 QTL had a marked impact on SBP, as did the QTLs on chromosome 2a and 2c (18, 17, and 19 mmHg, respectively), but not the QTL on chromosome 4. Thus these four QTLs affected BP phenotypes differently: 1) in the presence of high salt intake (chromosome 16), 2) only associated with normal salt intake (chromosome 4), and 3) regardless of salt intake (chromosome 2c and 2a). Moreover, salt sensitivity was abrogated in congenics SHR.BN2a and SHR.BN16. Finally, we provide evidence for the influence of genetic background on the expression of the mapped QTLs individually or as a group. Collectively, these data reveal previously unsuspected nuances of the physiological roles of each of the four mapped BP QTLs in the SHR under basal and/or salt loading conditions unforeseen by the analysis of the F2 cross.