RESUMO
The origins and developmental mechanisms of coronary arteries are incompletely understood. We show here by fate mapping, clonal analysis, and immunohistochemistry that endocardial cells generate the endothelium of coronary arteries. Dye tracking, live imaging, and tissue transplantation also revealed that ventricular endocardial cells are not terminally differentiated; instead, they are angiogenic and form coronary endothelial networks. Myocardial Vegf-a or endocardial Vegfr-2 deletion inhibited coronary angiogenesis and arterial formation by ventricular endocardial cells. In contrast, lineage and knockout studies showed that endocardial cells make a small contribution to the coronary veins, the formation of which is independent of myocardial-to-endocardial Vegf signaling. Thus, contrary to the current view of a common source for the coronary vessels, our findings indicate that the coronary arteries and veins have distinct origins and are formed by different mechanisms. This information may help develop better cell therapies for coronary artery disease.
Assuntos
Vasos Coronários/embriologia , Células Endoteliais/citologia , Miocárdio/citologia , Neovascularização Fisiológica , Transdução de Sinais , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Animais , Diferenciação Celular , Vasos Coronários/citologia , Vasos Coronários/metabolismo , Células Endoteliais/metabolismo , Camundongos , Miocárdio/metabolismo , Fatores de Transcrição NFATC/metabolismoRESUMO
BACKGROUND: Heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation (AF) frequently co-exist. There is a limited understanding on whether this coexistence is associated with distinct alterations in myocardial remodelling and mechanics. We aimed to determine if patients with atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF) represent a distinct phenotype. METHODS: In this secondary analysis of adults with HFpEF (NCT03050593), participants were comprehensively phenotyped with stress cardiac MRI, echocardiography and plasma fibroinflammatory biomarkers, and were followed for the composite endpoint (HF hospitalisation or death) at a median of 8.5 years. Those with AF were compared to sinus rhythm (SR) and unsupervised cluster analysis was performed to explore possible phenotypes. RESULTS: 136 subjects were included (SR = 75, AF = 61). The AF group was older (76 ± 8 vs. 70 ± 10 years) with less diabetes (36% vs. 61%) compared to the SR group and had higher left atrial (LA) volumes (61 ± 30 vs. 39 ± 15 mL/m2, p < 0.001), lower LA ejection fraction (EF) (31 ± 15 vs. 51 ± 12%, p < 0.001), worse left ventricular (LV) systolic function (LVEF 63 ± 8 vs. 68 ± 8%, p = 0.002; global longitudinal strain 13.6 ± 2.9 vs. 14.7 ± 2.4%, p = 0.003) but higher LV peak early diastolic strain rates (0.73 ± 0.28 vs. 0.53 ± 0.17 1/s, p < 0.001). The AF group had higher levels of syndecan-1, matrix metalloproteinase-2, proBNP, angiopoietin-2 and pentraxin-3, but lower level of interleukin-8. No difference in clinical outcomes was observed between the groups. Three distinct clusters were identified with the poorest outcomes (Log-rank p = 0.029) in cluster 2 (hypertensive and fibroinflammatory) which had equal representation of SR and AF. CONCLUSIONS: Presence of AF in HFpEF is associated with cardiac structural and functional changes together with altered expression of several fibro-inflammatory biomarkers. Distinct phenotypes exist in HFpEF which may have differing clinical outcomes.
Assuntos
Fibrilação Atrial , Insuficiência Cardíaca , Imageamento por Ressonância Magnética Multiparamétrica , Humanos , Adulto , Volume Sistólico , Metaloproteinase 2 da Matriz , Função Ventricular Esquerda , Biomarcadores , Fenótipo , PrognósticoRESUMO
BACKGROUND: Calmodulin mutations are associated with arrhythmia syndromes in humans. Exome sequencing previously identified a de novo mutation in CALM1 resulting in a p.N98S substitution in a patient with sinus bradycardia and stress-induced bidirectional ventricular ectopy. The objectives of the present study were to determine if mice carrying the N98S mutation knocked into Calm1 replicate the human arrhythmia phenotype and to examine arrhythmia mechanisms. METHODS: Mouse lines heterozygous for the Calm1N98S allele (Calm1N98S/+) were generated using CRISPR/Cas9 technology. Adult mutant mice and their wildtype littermates (Calm1+/+) underwent electrocardiographic monitoring. Ventricular de- and repolarization was assessed in isolated hearts using optical voltage mapping. Action potentials and whole-cell currents and [Ca2+]i, as well, were measured in single ventricular myocytes using the patch-clamp technique and fluorescence microscopy, respectively. The microelectrode technique was used for in situ membrane voltage monitoring of ventricular conduction fibers. RESULTS: Two biologically independent knock-in mouse lines heterozygous for the Calm1N98S allele were generated. Calm1N98S/+ mice of either sex and line exhibited sinus bradycardia, QTc interval prolongation, and catecholaminergic bidirectional ventricular tachycardia. Male mutant mice also showed QRS widening. Pharmacological blockade and activation of ß-adrenergic receptors rescued and exacerbated, respectively, the long-QT phenotype of Calm1N98S/+ mice. Optical and electric assessment of membrane potential in isolated hearts and single left ventricular myocytes, respectively, revealed ß-adrenergically induced delay of repolarization. ß-Adrenergic stimulation increased peak density, slowed inactivation, and left-shifted the activation curve of ICa.L significantly more in Calm1N98S/+ versus Calm1+/+ ventricular myocytes, increasing late ICa.L in the former. Rapidly paced Calm1N98S/+ ventricular myocytes showed increased propensity to delayed afterdepolarization-induced triggered activity, whereas in situ His-Purkinje fibers exhibited increased susceptibility for pause-dependent early afterdepolarizations. Epicardial mapping of Calm1N98S/+ hearts showed that both reentry and focal mechanisms contribute to arrhythmogenesis. CONCLUSIONS: Heterozygosity for the Calm1N98S mutation is causative of an arrhythmia syndrome characterized by sinus bradycardia, QRS widening, adrenergically mediated QTc interval prolongation, and bidirectional ventricular tachycardia. ß-Adrenergically induced ICa.L dysregulation contributes to the long-QT phenotype. Pause-dependent early afterdepolarizations and tachycardia-induced delayed afterdepolarizations originating in the His-Purkinje network and ventricular myocytes, respectively, constitute potential sources of arrhythmia in Calm1N98S/+ hearts.
Assuntos
Calmodulina , Ventrículos do Coração/metabolismo , Mutação de Sentido Incorreto , Miócitos Cardíacos/metabolismo , Ramos Subendocárdicos/metabolismo , Síndrome do Nó Sinusal/congênito , Substituição de Aminoácidos , Animais , Calmodulina/genética , Calmodulina/metabolismo , Modelos Animais de Doenças , Ventrículos do Coração/fisiopatologia , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Ramos Subendocárdicos/fisiopatologia , Síndrome do Nó Sinusal/genética , Síndrome do Nó Sinusal/metabolismo , Síndrome do Nó Sinusal/fisiopatologiaRESUMO
CHARGE syndrome is a multiple anomaly disorder in which patients present with a variety of phenotypes, including ocular coloboma, heart defects, choanal atresia, retarded growth and development, genitourinary hypoplasia and ear abnormalities. Despite 70-90% of CHARGE syndrome cases resulting from mutations in the gene CHD7, which encodes an ATP-dependent chromatin remodeller, the pathways underlying the diverse phenotypes remain poorly understood. Surprisingly, our studies of a knock-in mutant mouse strain that expresses a stabilized and transcriptionally dead variant of the tumour-suppressor protein p53 (p53(25,26,53,54)), along with a wild-type allele of p53 (also known as Trp53), revealed late-gestational embryonic lethality associated with a host of phenotypes that are characteristic of CHARGE syndrome, including coloboma, inner and outer ear malformations, heart outflow tract defects and craniofacial defects. We found that the p53(25,26,53,54) mutant protein stabilized and hyperactivated wild-type p53, which then inappropriately induced its target genes and triggered cell-cycle arrest or apoptosis during development. Importantly, these phenotypes were only observed with a wild-type p53 allele, as p53(25,26,53,54)(/-) embryos were fully viable. Furthermore, we found that CHD7 can bind to the p53 promoter, thereby negatively regulating p53 expression, and that CHD7 loss in mouse neural crest cells or samples from patients with CHARGE syndrome results in p53 activation. Strikingly, we found that p53 heterozygosity partially rescued the phenotypes in Chd7-null mouse embryos, demonstrating that p53 contributes to the phenotypes that result from CHD7 loss. Thus, inappropriate p53 activation during development can promote CHARGE phenotypes, supporting the idea that p53 has a critical role in developmental syndromes and providing important insight into the mechanisms underlying CHARGE syndrome.
Assuntos
Anormalidades Múltiplas/metabolismo , Síndrome CHARGE/genética , Síndrome CHARGE/metabolismo , Fenótipo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Anormalidades Múltiplas/genética , Alelos , Animais , Apoptose/genética , Pontos de Checagem do Ciclo Celular/genética , Anormalidades Craniofaciais/genética , Anormalidades Craniofaciais/metabolismo , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Orelha/anormalidades , Embrião de Mamíferos/anormalidades , Embrião de Mamíferos/metabolismo , Feminino , Fibroblastos , Deleção de Genes , Heterozigoto , Humanos , Masculino , Camundongos , Proteínas Mutantes/metabolismo , Regiões Promotoras Genéticas/genéticaRESUMO
The role of long noncoding RNA (lncRNA) in adult hearts is unknown; also unclear is how lncRNA modulates nucleosome remodelling. An estimated 70% of mouse genes undergo antisense transcription, including myosin heavy chain 7 (Myh7), which encodes molecular motor proteins for heart contraction. Here we identify a cluster of lncRNA transcripts from Myh7 loci and demonstrate a new lncRNA-chromatin mechanism for heart failure. In mice, these transcripts, which we named myosin heavy-chain-associated RNA transcripts (Myheart, or Mhrt), are cardiac-specific and abundant in adult hearts. Pathological stress activates the Brg1-Hdac-Parp chromatin repressor complex to inhibit Mhrt transcription in the heart. Such stress-induced Mhrt repression is essential for cardiomyopathy to develop: restoring Mhrt to the pre-stress level protects the heart from hypertrophy and failure. Mhrt antagonizes the function of Brg1, a chromatin-remodelling factor that is activated by stress to trigger aberrant gene expression and cardiac myopathy. Mhrt prevents Brg1 from recognizing its genomic DNA targets, thus inhibiting chromatin targeting and gene regulation by Brg1. It does so by binding to the helicase domain of Brg1, a domain that is crucial for tethering Brg1 to chromatinized DNA targets. Brg1 helicase has dual nucleic-acid-binding specificities: it is capable of binding lncRNA (Mhrt) and chromatinized--but not naked--DNA. This dual-binding feature of helicase enables a competitive inhibition mechanism by which Mhrt sequesters Brg1 from its genomic DNA targets to prevent chromatin remodelling. A Mhrt-Brg1 feedback circuit is thus crucial for heart function. Human MHRT also originates from MYH7 loci and is repressed in various types of myopathic hearts, suggesting a conserved lncRNA mechanism in human cardiomyopathy. Our studies identify a cardioprotective lncRNA, define a new targeting mechanism for ATP-dependent chromatin-remodelling factors, and establish a new paradigm for lncRNA-chromatin interaction.
Assuntos
Cardiomegalia/genética , Cardiomegalia/patologia , Cadeias Pesadas de Miosina/genética , RNA Longo não Codificante/genética , Animais , Miosinas Cardíacas/genética , Cardiomegalia/prevenção & controle , Cardiomiopatias/genética , Cardiomiopatias/patologia , Cardiomiopatias/prevenção & controle , Cromatina/genética , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina , DNA Helicases/antagonistas & inibidores , DNA Helicases/química , DNA Helicases/genética , DNA Helicases/metabolismo , Retroalimentação Fisiológica , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/patologia , Insuficiência Cardíaca/prevenção & controle , Histona Desacetilases/metabolismo , Humanos , Camundongos , Miocárdio/metabolismo , Miocárdio/patologia , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/química , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Especificidade de Órgãos , Poli(ADP-Ribose) Polimerase-1 , Poli(ADP-Ribose) Polimerases/metabolismo , Ligação Proteica , Estrutura Terciária de Proteína , RNA Longo não Codificante/antagonistas & inibidores , RNA Longo não Codificante/metabolismo , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/química , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Genes encoding angiotensin-converting enzymes (Ace and Ace2) are essential for heart function regulation. Cardiac stress enhances Ace, but suppresses Ace2, expression in the heart, leading to a net production of angiotensin II that promotes cardiac hypertrophy and fibrosis. The regulatory mechanism that underlies the Ace2-to-Ace pathological switch, however, is unknown. Here we report that the Brahma-related gene-1 (Brg1) chromatin remodeler and forkhead box M1 (FoxM1) transcription factor cooperate within cardiac (coronary) endothelial cells of pathologically stressed hearts to trigger the Ace2-to-Ace enzyme switch, angiotensin I-to-II conversion, and cardiac hypertrophy. In mice, cardiac stress activates the expression of Brg1 and FoxM1 in endothelial cells. Once activated, Brg1 and FoxM1 form a protein complex on Ace and Ace2 promoters to concurrently activate Ace and repress Ace2, tipping the balance to Ace2 expression with enhanced angiotensin II production, leading to cardiac hypertrophy and fibrosis. Disruption of endothelial Brg1 or FoxM1 or chemical inhibition of FoxM1 abolishes the stress-induced Ace2-to-Ace switch and protects the heart from pathological hypertrophy. In human hypertrophic hearts, BRG1 and FOXM1 expression is also activated in endothelial cells; their expression levels correlate strongly with the ACE/ACE2 ratio, suggesting a conserved mechanism. Our studies demonstrate a molecular interaction of Brg1 and FoxM1 and an endothelial mechanism of modulating Ace/Ace2 ratio for heart failure therapy.
Assuntos
Cardiomegalia/metabolismo , DNA Helicases/genética , Proteína Forkhead Box M1/genética , Insuficiência Cardíaca/genética , Proteínas Nucleares/genética , Peptidil Dipeptidase A/genética , Fatores de Transcrição/genética , Angiotensina II/biossíntese , Angiotensina II/genética , Enzima de Conversão de Angiotensina 2 , Animais , Cardiomegalia/tratamento farmacológico , Cardiomegalia/genética , Cardiomegalia/patologia , DNA Helicases/metabolismo , Modelos Animais de Doenças , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Proteína Forkhead Box M1/metabolismo , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/patologia , Humanos , Camundongos , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Miocárdio/metabolismo , Miocárdio/patologia , Proteínas Nucleares/metabolismo , Peptidil Dipeptidase A/metabolismo , Tioestreptona/administração & dosagem , Fatores de Transcrição/metabolismoRESUMO
Our developmental studies provide an insight into the pathogenesis of heart failure in adults. These studies reveal a mechanistic link between fetal cardiomyocytes and pathologically stressed adult cardiomyocytes at the level of chromatin regulation. In embryos, chromatin-regulating factors within the cardiomyocytes respond to developmental signals to program cardiac gene expression to promote cell proliferation and inhibit premature cell differentiation. In the neonatal period, the activity of these developmental chromatin regulators is quickly turned off in cardiomyocytes, coinciding with the cessation of cell proliferation and advance in cell differentiation toward adult maturity. When the mature hearts are pathologically stressed, those chromatin regulators essential for cardiomyocyte development in embryos are reactivated, triggering gene reprogramming to a fetal-like state and pathological cardiac hypertrophy. Furthermore, in the study of chromatin regulation and cardiac gene expression, we identified a long noncoding RNA that interacts with chromatin remodeling factor to regulate the cardiac response to environmental changes. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
Assuntos
Epigênese Genética , Cardiopatias/genética , Miócitos Cardíacos , RNA Longo não Codificante/genética , Animais , Montagem e Desmontagem da Cromatina , DNA Helicases/genética , DNA Helicases/metabolismo , Regulação da Expressão Gênica , Interação Gene-Ambiente , Predisposição Genética para Doença , Cardiopatias/metabolismo , Cardiopatias/patologia , Cardiopatias/fisiopatologia , Humanos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Fenótipo , RNA Longo não Codificante/metabolismo , Fatores de Risco , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Chromatin structure is determined by nucleosome positioning, histone modifications, and DNA methylation. How chromatin modifications are coordinately altered under pathological conditions remains elusive. Here we describe a stress-activated mechanism of concerted chromatin modification in the heart. In mice, pathological stress activates cardiomyocytes to express Brg1 (nucleosome-remodeling factor), G9a/Glp (histone methyltransferase), and Dnmt3 (DNA methyltransferase). Once activated, Brg1 recruits G9a and then Dnmt3 to sequentially assemble repressive chromatin-marked by H3K9 and CpG methylation-on a key molecular motor gene (Myh6), thereby silencing Myh6 and impairing cardiac contraction. Disruption of Brg1, G9a or Dnmt3 erases repressive chromatin marks and de-represses Myh6, reducing stress-induced cardiac dysfunction. In human hypertrophic hearts, BRG1-G9a/GLP-DNMT3 complex is also activated; its level correlates with H3K9/CpG methylation, Myh6 repression, and cardiomyopathy. Our studies demonstrate a new mechanism of chromatin assembly in stressed hearts and novel therapeutic targets for restoring Myh6 and ventricular function. The stress-induced Brg1-G9a-Dnmt3 interactions and sequence of repressive chromatin assembly on Myh6 illustrates a molecular mechanism by which the heart epigenetically responds to environmental signals. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
Assuntos
Cardiomegalia/enzimologia , Cardiomiopatias/enzimologia , Montagem e Desmontagem da Cromatina , Cromatina/metabolismo , DNA (Citosina-5-)-Metiltransferases/metabolismo , DNA Helicases/metabolismo , Epigênese Genética , Histona-Lisina N-Metiltransferase/metabolismo , Miocárdio/enzimologia , Cadeias Pesadas de Miosina/metabolismo , Proteínas Nucleares/metabolismo , Regiões Promotoras Genéticas , Estresse Fisiológico , Fatores de Transcrição/metabolismo , Adaptação Fisiológica , Animais , Cardiomegalia/genética , Cardiomegalia/patologia , Cardiomegalia/fisiopatologia , Cardiomiopatias/genética , Cardiomiopatias/patologia , Cardiomiopatias/fisiopatologia , Cromatina/genética , Ilhas de CpG , DNA (Citosina-5-)-Metiltransferases/deficiência , DNA (Citosina-5-)-Metiltransferases/genética , DNA Helicases/deficiência , DNA Helicases/genética , Metilação de DNA , DNA Metiltransferase 3A , Modelos Animais de Doenças , Idade Gestacional , Histona-Lisina N-Metiltransferase/deficiência , Histona-Lisina N-Metiltransferase/genética , Histonas/metabolismo , Humanos , Metilação , Camundongos Knockout , Miocárdio/patologia , Cadeias Pesadas de Miosina/genética , Proteínas Nucleares/deficiência , Proteínas Nucleares/genética , Ligação Proteica , Processamento de Proteína Pós-Traducional , Recuperação de Função Fisiológica , Transdução de Sinais , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Função Ventricular EsquerdaRESUMO
Cardiac hypertrophy and failure are characterized by transcriptional reprogramming of gene expression. Adult cardiomyocytes in mice primarily express alpha-myosin heavy chain (alpha-MHC, also known as Myh6), whereas embryonic cardiomyocytes express beta-MHC (also known as Myh7). Cardiac stress triggers adult hearts to undergo hypertrophy and a shift from alpha-MHC to fetal beta-MHC expression. Here we show that Brg1, a chromatin-remodelling protein, has a critical role in regulating cardiac growth, differentiation and gene expression. In embryos, Brg1 promotes myocyte proliferation by maintaining Bmp10 and suppressing p57(kip2) expression. It preserves fetal cardiac differentiation by interacting with histone deacetylase (HDAC) and poly (ADP ribose) polymerase (PARP) to repress alpha-MHC and activate beta-MHC. In adults, Brg1 (also known as Smarca4) is turned off in cardiomyocytes. It is reactivated by cardiac stresses and forms a complex with its embryonic partners, HDAC and PARP, to induce a pathological alpha-MHC to beta-MHC shift. Preventing Brg1 re-expression decreases hypertrophy and reverses this MHC switch. BRG1 is activated in certain patients with hypertrophic cardiomyopathy, its level correlating with disease severity and MHC changes. Our studies show that Brg1 maintains cardiomyocytes in an embryonic state, and demonstrate an epigenetic mechanism by which three classes of chromatin-modifying factors-Brg1, HDAC and PARP-cooperate to control developmental and pathological gene expression.
Assuntos
Cardiomegalia/genética , Cardiomegalia/metabolismo , Cromatina/genética , DNA Helicases/metabolismo , Miocárdio/metabolismo , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Animais , Cardiomegalia/patologia , Diferenciação Celular , Proliferação de Células , DNA Helicases/deficiência , DNA Helicases/genética , Perda do Embrião/genética , Embrião de Mamíferos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Histona Desacetilases/metabolismo , Humanos , Camundongos , Miocárdio/citologia , Miocárdio/patologia , Cadeias Pesadas de Miosina/genética , Cadeias Pesadas de Miosina/metabolismo , Proteínas Nucleares/deficiência , Proteínas Nucleares/genética , Poli(ADP-Ribose) Polimerase-1 , Poli(ADP-Ribose) Polimerases/metabolismo , Fatores de Transcrição/deficiência , Fatores de Transcrição/genéticaRESUMO
Heterozygous mutations in the gene encoding the CHD (chromodomain helicase DNA-binding domain) member CHD7, an ATP-dependent chromatin remodeller homologous to the Drosophila trithorax-group protein Kismet, result in a complex constellation of congenital anomalies called CHARGE syndrome, which is a sporadic, autosomal dominant disorder characterized by malformations of the craniofacial structures, peripheral nervous system, ears, eyes and heart. Although it was postulated 25 years ago that CHARGE syndrome results from the abnormal development of the neural crest, this hypothesis remained untested. Here we show that, in both humans and Xenopus, CHD7 is essential for the formation of multipotent migratory neural crest (NC), a transient cell population that is ectodermal in origin but undergoes a major transcriptional reprogramming event to acquire a remarkably broad differentiation potential and ability to migrate throughout the body, giving rise to craniofacial bones and cartilages, the peripheral nervous system, pigmentation and cardiac structures. We demonstrate that CHD7 is essential for activation of the NC transcriptional circuitry, including Sox9, Twist and Slug. In Xenopus embryos, knockdown of Chd7 or overexpression of its catalytically inactive form recapitulates all major features of CHARGE syndrome. In human NC cells CHD7 associates with PBAF (polybromo- and BRG1-associated factor-containing complex) and both remodellers occupy a NC-specific distal SOX9 enhancer and a conserved genomic element located upstream of the TWIST1 gene. Consistently, during embryogenesis CHD7 and PBAF cooperate to promote NC gene expression and cell migration. Our work identifies an evolutionarily conserved role for CHD7 in orchestrating NC gene expression programs, provides insights into the synergistic control of distal elements by chromatin remodellers, illuminates the patho-embryology of CHARGE syndrome, and suggests a broader function for CHD7 in the regulation of cell motility.
Assuntos
Proteínas Cromossômicas não Histona/metabolismo , DNA Helicases/metabolismo , Proteínas de Ligação a DNA/metabolismo , Células-Tronco Multipotentes/citologia , Células-Tronco Multipotentes/metabolismo , Crista Neural/citologia , Crista Neural/metabolismo , Fatores de Transcrição/metabolismo , Proteínas de Xenopus/metabolismo , Animais , Diferenciação Celular , Linhagem Celular , Linhagem da Célula , Movimento Celular , Proteínas Cromossômicas não Histona/genética , DNA Helicases/química , DNA Helicases/deficiência , DNA Helicases/genética , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Embrião não Mamífero/citologia , Embrião não Mamífero/embriologia , Embrião não Mamífero/metabolismo , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Elementos Facilitadores Genéticos/genética , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Crista Neural/embriologia , Ligação Proteica , Fatores de Transcrição SOX9/genética , Fatores de Transcrição SOX9/metabolismo , Fatores de Transcrição da Família Snail , Síndrome , Fatores de Transcrição/genética , Transcrição Gênica , Proteína 1 Relacionada a Twist/genética , Proteína 1 Relacionada a Twist/metabolismo , Proteínas de Xenopus/química , Proteínas de Xenopus/deficiência , Proteínas de Xenopus/genética , Xenopus laevis/embriologia , Xenopus laevis/genética , Xenopus laevis/metabolismoRESUMO
Development of the cerebral vessels, pharyngeal arch arteries (PAAs). and cardiac outflow tract (OFT) requires multipotent neural crest cells (NCCs) that migrate from the neural tube to target tissue destinations. Little is known about how mammalian NCC development is orchestrated by gene programming at the chromatin level, however. Here we show that Brahma-related gene 1 (Brg1), an ATPase subunit of the Brg1/Brahma-associated factor (BAF) chromatin-remodeling complex, is required in NCCs to direct cardiovascular development. Mouse embryos lacking Brg1 in NCCs display immature cerebral vessels, aberrant PAA patterning, and shortened OFT. Brg1 suppresses an apoptosis factor, Apoptosis signal-regulating kinase 1 (Ask1), and a cell cycle inhibitor, p21(cip1), to inhibit apoptosis and promote proliferation of NCCs, thereby maintaining a multipotent cell reservoir at the neural crest. Brg1 also supports Myosin heavy chain 11 (Myh11) expression to allow NCCs to develop into mature vascular smooth muscle cells of cerebral vessels. Within NCCs, Brg1 partners with chromatin remodeler Chromodomain-helicase-DNA-binding protein 7 (Chd7) on the PlexinA2 promoter to activate PlexinA2, which encodes a receptor for semaphorin to guide NCCs into the OFT. Our findings reveal an important role for Brg1 and its downstream pathways in the survival, differentiation, and migration of the multipotent NCCs critical for mammalian cardiovascular development.
Assuntos
DNA Helicases/genética , Células-Tronco Multipotentes/metabolismo , Células-Tronco Neurais/metabolismo , Proteínas Nucleares/genética , Transdução de Sinais/genética , Fatores de Transcrição/genética , Animais , Apoptose/genética , Sistema Cardiovascular/citologia , Sistema Cardiovascular/embriologia , Sistema Cardiovascular/metabolismo , Movimento Celular/genética , Proliferação de Células , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , DNA Helicases/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Embrião de Mamíferos/irrigação sanguínea , Embrião de Mamíferos/citologia , Embrião de Mamíferos/embriologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Hibridização In Situ , MAP Quinase Quinase Quinase 5/genética , MAP Quinase Quinase Quinase 5/metabolismo , Camundongos , Microscopia de Fluorescência , Mutação , Cadeias Pesadas de Miosina/genética , Cadeias Pesadas de Miosina/metabolismo , Crista Neural/citologia , Crista Neural/embriologia , Crista Neural/metabolismo , Proteínas Nucleares/metabolismo , Gravidez , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição/metabolismoRESUMO
The cardiovascular system is broadly composed of the heart, which pumps blood, and the blood vessels, which carry blood to and from tissues of the body. Heart malformations are the most serious common birth defect, affecting at least 2% of newborns and leading to significant morbidity and mortality. Severe heart malformations cause heart failure in fetuses, infants, and children, whereas milder heart defects may not trigger significant heart dysfunction until early or midadulthood. Severe vasculogenesis or angiogenesis defects in embryos are incompatible with life, and anomalous arterial patterning may cause vascular aberrancies that often require surgical treatment. It is therefore important to understand the underlying mechanisms that control cardiovascular development. Understanding developmental mechanisms will also help us design better strategies to regenerate cardiovascular tissues for therapeutic purposes. An important mechanism regulating genes involves the modification of chromatin, the higher-order structure in which DNA is packaged. Recent studies have greatly expanded our understanding of the regulation of cardiovascular development at the chromatin level, including the remodeling of chromatin and the modification of histones. Chromatin-level regulation integrates multiple inputs and coordinates broad gene expression programs. Thus, understanding chromatin-level regulation will allow for a better appreciation of gene regulation as a whole and may set a fundamental basis for cardiovascular disease. This review focuses on how chromatin-remodeling and histone-modifying factors regulate gene expression to control cardiovascular development.
Assuntos
Sistema Cardiovascular/crescimento & desenvolvimento , Epigenômica , Trifosfato de Adenosina/fisiologia , Animais , Artérias/fisiologia , Vasos Sanguíneos/embriologia , Vasos Sanguíneos/crescimento & desenvolvimento , Sistema Cardiovascular/embriologia , Cromatina/fisiologia , Epigênese Genética , Coração/crescimento & desenvolvimento , Coração/fisiologia , Cardiopatias Congênitas/fisiopatologia , Histona Desacetilases/fisiologia , Histonas/metabolismo , Histonas/fisiologia , Humanos , Miocárdio , Doenças Vasculares/congênito , Doenças Vasculares/fisiopatologiaRESUMO
Heart malformations are common congenital defects in humans. Many congenital heart defects involve anomalies in cardiac septation or valve development, and understanding the developmental mechanisms that underlie the formation of cardiac septal and valvular tissues thus has important implications for the diagnosis, prevention and treatment of congenital heart disease. The development of heart septa and valves involves multiple types of progenitor cells that arise either within or outside the heart. Here, we review the morphogenetic events and genetic networks that regulate spatiotemporal interactions between the cells that give rise to septal and valvular tissues and hence partition the heart.
Assuntos
Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Septos Cardíacos/embriologia , Valvas Cardíacas/embriologia , Morfogênese/fisiologia , Animais , Regulação da Expressão Gênica no Desenvolvimento/genética , Humanos , Morfogênese/genéticaRESUMO
Long noncoding RNAs (lncRNAs) are pivotal regulators of genome structure and gene expression. LncRNAs can directly interact with chromatin-modifying enzymes and nucleosome-remodeling factors to control chromatin structure and accessibility of genetic information. Moreover, lncRNA expression can be controlled by chromatin-remodeling factors, suggesting a feedback circuit of regulation. Here, we discuss the recent advances of lncRNA studies, focusing on the function and mechanism of lncRNA-chromatin interactions.
Assuntos
Montagem e Desmontagem da Cromatina/genética , Doenças Genéticas Inatas/terapia , RNA Longo não Codificante/genética , Cromatina/genética , Regulação da Expressão Gênica , Doenças Genéticas Inatas/genética , Humanos , RNA/genética , RNA/uso terapêutico , RNA Longo não Codificante/uso terapêuticoRESUMO
Insufficiency of surfactants is a core factor in respiratory distress syndrome, which causes apnea and neonatal death, particularly in preterm infants. Surfactant proteins are secreted by alveolar type II cells in the lung epithelium, the differentiation of which is regulated by Fgf10 elaborated by the adjacent mesenchyme. However, the molecular regulation of mesenchymal Fgf10 during lung development has not been fully understood. Here, we show that Pbx1, a homeodomain transcription factor, is required in the lung mesenchyme for the expression of Fgf10. Mouse embryos lacking Pbx1 in the lung mesenchyme show compact terminal saccules and perinatal lethality with failure of postnatal alveolar expansion. Mutant embryos had severely reduced expression of Fgf10 and surfactant genes (Spa, Spb, Spc, and Spd) that are essential for alveolar expansion for gas exchange at birth. Molecularly, Pbx1 directly binds to the Fgf10 promoter and cooperates with Meis and Hox proteins to transcriptionally activate Fgf10. Our results thus show how Pbx1 controls Fgf10 in the developing lung.
Assuntos
Fator 10 de Crescimento de Fibroblastos/metabolismo , Proteínas de Homeodomínio/metabolismo , Pulmão/crescimento & desenvolvimento , Mesoderma/metabolismo , Fatores de Transcrição/metabolismo , Animais , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio/genética , Pulmão/metabolismo , Mesoderma/crescimento & desenvolvimento , Camundongos , Camundongos Transgênicos , Fator de Transcrição 1 de Leucemia de Células Pré-B , Gravidez , Regiões Promotoras Genéticas , Fatores de Transcrição/genéticaRESUMO
An increase of late Na(+) current (INaL) in cardiac myocytes can raise the cytosolic Na(+) concentration and is associated with activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and alterations of mitochondrial metabolism and Ca(2+) handling by sarcoplasmic reticulum (SR). We tested the hypothesis that augmentation of INaL can increase mitochondrial reactive oxygen species (ROS) production and oxidation of CaMKII, resulting in spontaneous SR Ca(2+) release and increased diastolic Ca(2+) in myocytes. Increases of INaL and/or of the cytosolic Na(+) concentration led to mitochondrial ROS production and oxidation of CaMKII to cause dysregulation of Ca(2+) handling in rabbit cardiac myocytes.
Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Miócitos Cardíacos/enzimologia , Sódio/metabolismo , Potenciais de Ação , Animais , Sinalização do Cálcio , Feminino , Ventrículos do Coração/citologia , Ventrículos do Coração/enzimologia , Espaço Intracelular/metabolismo , Oxirredução , Estresse Oxidativo , Coelhos , Espécies Reativas de Oxigênio/metabolismoRESUMO
BACKGROUND: Although several studies have addressed plasma proteomics in heart failure with preserved ejection fraction, limited data are available on the prognostic value of urinary proteomics. The objective of our study was to identify urinary proteins/peptides associated with death and heart failure admission in patients with heart failure with preserved ejection fraction. METHODS AND RESULTS: The study population included participants enrolled in TOPCAT (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist Trial). The relationship between urine protein levels and the risk of death or heart failure admission was assessed using Cox regression, in both nonadjusted analyses and adjusting for urine creatinine levels, and the MAGGIC (Meta-Analysis Global Group in Chronic Heart Failure) score. A total of 426 (12.4%) TOPCAT participants had urinary protein data and were included. There were 40 urinary proteins/peptides significantly associated with death or heart failure admission in nonadjusted analyses, 21 of which were also significant adjusted analyses. Top proteins in the adjusted analysis included ANGPTL2 (angiopoietin-like protein 2) (hazard ratio [HR], 0.5731 [95% CI, 0.47-0.7]; P=3.13E-05), AMY2A (α amylase 2A) (HR, 0.5496 [95% CI, 0.44-0.69]; P=0.0001), and DNASE1 (deoxyribonuclease-1) (HR, 0.5704 [95% CI, 0.46-0.71]; P=0.0002). Higher urinary levels of proteins involved in fibrosis (collagen VI α-1, collagen XV α-1), metabolism (pancreatic α-amylase 2A/B, mannosidase α class 1A member 1), and inflammation (heat shock protein family D member 1, inducible T cell costimulatory ligand) were associated with a lower risk of death or heart failure admission. CONCLUSIONS: Our study identifies several novel associations between urinary proteins/peptides and outcomes in heart failure with preserved ejection fraction. Many of these associations are independent of clinical risk scores and may aid in risk stratification in this patient population.
Assuntos
Proteína 2 Semelhante a Angiopoietina , Biomarcadores , Insuficiência Cardíaca , Proteômica , Volume Sistólico , Humanos , Insuficiência Cardíaca/urina , Insuficiência Cardíaca/mortalidade , Insuficiência Cardíaca/fisiopatologia , Masculino , Feminino , Proteômica/métodos , Idoso , Biomarcadores/urina , Biomarcadores/sangue , Pessoa de Meia-Idade , Prognóstico , Antagonistas de Receptores de Mineralocorticoides/uso terapêutico , Função Ventricular Esquerda , Fatores de Risco , Medição de Risco , Proteinúria/urina , Proteinúria/diagnósticoRESUMO
BACKGROUND: NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels are variably elevated in heart failure with preserved ejection fraction (HFpEF), even in the presence of increased left ventricular filling pressures. NT-proBNP levels are prognostic in HFpEF and have been used as an inclusion criterion for several recent randomized clinical trials. However, the underlying biologic differences between HFpEF participants with high and low NT-proBNP levels remain to be fully understood. METHODS: We measured 4928 proteins using an aptamer-based proteomic assay (SOMAScan) in available plasma samples from 2 cohorts: (1) Participants with HFpEF enrolled in the PHFS (Penn Heart Failure Study; n=253); (2) TOPCAT (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist Trial) participants in the Americas (n=218). We assessed the relationship between SOMAScan-derived plasma NT-proBNP and levels of other proteins available in the SOMAScan assay version 4 using robust linear regression, with correction for multiple comparisons, followed by pathway analysis. RESULTS: NT-proBNP levels exhibited prominent proteome-wide associations in PHFS and TOPCAT cohorts. Proteins most strongly associated with NT-proBNP in both cohorts included SVEP1 (sushi, von Willebrand factor type-A, epidermal growth factor, and pentraxin domain containing 1; ßTOPCAT=0.539; P<0.0001; ßPHFS=0.516; P<0.0001) and ANGPT2 (angiopoietin 2; ßTOPCAT=0.571; P<0.0001; ßPHFS=0.459; P<0.0001). Canonical pathway analysis demonstrated consistent associations with multiple pathways related to fibrosis and inflammation. These included hepatic fibrosis and inhibition of matrix metalloproteases. Analyses using cut points corresponding to estimated quantitative concentrations of 360 pg/mL (and 480 pg/mL in atrial fibrillation) revealed similar proteomic associations. CONCLUSIONS: Circulating NT-proBNP levels exhibit prominent proteomic associations in HFpEF. Our findings suggest that higher NT-proBNP levels in HFpEF are a marker of fibrosis and inflammation. These findings will aid the interpretation of NT-proBNP levels in HFpEF and may guide the selection of participants in future HFpEF clinical trials.
Assuntos
Insuficiência Cardíaca , Peptídeo Natriurético Encefálico , Humanos , Volume Sistólico/fisiologia , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/tratamento farmacológico , Proteômica , Prognóstico , Fragmentos de Peptídeos , Inflamação , Fibrose , BiomarcadoresRESUMO
BACKGROUND: Identifying novel molecular drivers of disease progression in heart failure (HF) is a high-priority goal that may provide new therapeutic targets to improve patient outcomes. The authors investigated the relationship between plasma proteins and adverse outcomes in HF and their putative causal role using Mendelian randomization. METHODS AND RESULTS: The authors measured 4776 plasma proteins among 1964 participants with HF with a reduced left ventricular ejection fraction enrolled in PHFS (Penn Heart Failure Study). Assessed were the observational relationship between plasma proteins and (1) all-cause death or (2) death or HF-related hospital admission (DHFA). The authors replicated nominally significant associations in the Washington University HF registry (N=1080). Proteins significantly associated with outcomes were the subject of 2-sample Mendelian randomization and colocalization analyses. After correction for multiple testing, 243 and 126 proteins were found to be significantly associated with death and DHFA, respectively. These included small ubiquitin-like modifier 2 (standardized hazard ratio [sHR], 1.56; P<0.0001), growth differentiation factor-15 (sHR, 1.68; P<0.0001) for death, A disintegrin and metalloproteinase with thrombospondin motifs-like protein (sHR, 1.40; P<0.0001), and pulmonary-associated surfactant protein C (sHR, 1.24; P<0.0001) for DHFA. In pathway analyses, top canonical pathways associated with death and DHFA included fibrotic, inflammatory, and coagulation pathways. Genomic analyses provided evidence of nominally significant associations between levels of 6 genetically predicted proteins with DHFA and 11 genetically predicted proteins with death. CONCLUSIONS: This study implicates multiple novel proteins in HF and provides preliminary evidence of associations between genetically predicted plasma levels of 17 candidate proteins and the risk for adverse outcomes in human HF.
Assuntos
Insuficiência Cardíaca , Proteômica , Humanos , Proteínas Sanguíneas , Volume Sistólico , Função Ventricular Esquerda , Análise da Randomização MendelianaRESUMO
Developing myocardial cells respond to signals from the endocardial layer to form a network of trabeculae that characterize the ventricles of the vertebrate heart. Abnormal myocardial trabeculation results in specific cardiomyopathies in humans and yet trabecular development is poorly understood. We show that trabeculation requires Brg1, a chromatin remodeling protein, to repress ADAMTS1 expression in the endocardium that overlies the developing trabeculae. Repression of ADAMTS1, a secreted matrix metalloproteinase, allows the establishment of an extracellular environment in the cardiac jelly that supports trabecular growth. Later during embryogenesis, ADAMTS1 expression initiates in the endocardium to degrade the cardiac jelly and prevent excessive trabeculation. Thus, the composition of cardiac jelly essential for myocardial morphogenesis is dynamically controlled by ADAMTS1 and its chromatin-based transcriptional regulation. Modification of the intervening microenvironment provides a mechanism by which chromatin regulation within one tissue layer coordinates the morphogenesis of an adjacent layer.