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1.
Circulation ; 147(5): 409-424, 2023 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-36448446

RESUMO

BACKGROUND: Extensive evidence from single-center studies indicates that a subset of patients with chronic advanced heart failure (HF) undergoing left ventricular assist device (LVAD) support show significantly improved heart function and reverse structural remodeling (ie, termed "responders"). Furthermore, we recently published a multicenter prospective study, RESTAGE-HF (Remission from Stage D Heart Failure), demonstrating that LVAD support combined with standard HF medications induced remarkable cardiac structural and functional improvement, leading to high rates of LVAD weaning and excellent long-term outcomes. This intriguing phenomenon provides great translational and clinical promise, although the underlying molecular mechanisms driving this recovery are largely unknown. METHODS: To identify changes in signaling pathways operative in the normal and failing human heart and to molecularly characterize patients who respond favorably to LVAD unloading, we performed global RNA sequencing and phosphopeptide profiling of left ventricular tissue from 93 patients with HF undergoing LVAD implantation (25 responders and 68 nonresponders) and 12 nonfailing donor hearts. Patients were prospectively monitored through echocardiography to characterize their myocardial structure and function and identify responders and nonresponders. RESULTS: These analyses identified 1341 transcripts and 288 phosphopeptides that are differentially regulated in cardiac tissue from nonfailing control samples and patients with HF. In addition, these unbiased molecular profiles identified a unique signature of 29 transcripts and 93 phosphopeptides in patients with HF that distinguished responders after LVAD unloading. Further analyses of these macromolecules highlighted differential regulation in 2 key pathways: cell cycle regulation and extracellular matrix/focal adhesions. CONCLUSIONS: This is the first study to characterize changes in the nonfailing and failing human heart by integrating multiple -omics platforms to identify molecular indices defining patients capable of myocardial recovery. These findings may guide patient selection for advanced HF therapies and identify new HF therapeutic targets.


Assuntos
Insuficiência Cardíaca , Transplante de Coração , Coração Auxiliar , Humanos , Transcriptoma , Estudos Prospectivos , Fosfopeptídeos/metabolismo , Proteômica , Doadores de Tecidos , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/terapia , Insuficiência Cardíaca/metabolismo , Miocárdio/metabolismo
3.
Basic Res Cardiol ; 118(1): 20, 2023 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-37212935

RESUMO

SMYD1, a striated muscle-specific lysine methyltransferase, was originally shown to play a key role in embryonic cardiac development but more recently we demonstrated that loss of Smyd1 in the murine adult heart leads to cardiac hypertrophy and failure. However, the effects of SMYD1 overexpression in the heart and its molecular function in the cardiomyocyte in response to ischemic stress are unknown. In this study, we show that inducible, cardiomyocyte-specific overexpression of SMYD1a in mice protects the heart from ischemic injury as seen by a > 50% reduction in infarct size and decreased myocyte cell death. We also demonstrate that attenuated pathological remodeling is a result of enhanced mitochondrial respiration efficiency, which is driven by increased mitochondrial cristae formation and stabilization of respiratory chain supercomplexes within the cristae. These morphological changes occur concomitant with increased OPA1 expression, a known driver of cristae morphology and supercomplex formation. Together, these analyses identify OPA1 as a novel downstream target of SMYD1a whereby cardiomyocytes upregulate energy efficiency to dynamically adapt to the energy demands of the cell. In addition, these findings highlight a new epigenetic mechanism by which SMYD1a regulates mitochondrial energetics and functions to protect the heart from ischemic injury.


Assuntos
Músculo Esquelético , Miócitos Cardíacos , Animais , Camundongos , Cardiomegalia/metabolismo , Mitocôndrias/metabolismo , Músculo Esquelético/metabolismo , Miócitos Cardíacos/metabolismo
4.
J Mol Cell Cardiol ; 158: 89-100, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34081951

RESUMO

Heart failure is a worldwide health condition that currently has limited noninvasive treatments. Heart disease includes both structural and molecular remodeling of the heart which is driven by alterations in gene expression in the cardiomyocyte. Therefore, understanding the regulatory mechanisms which instigate these changes in gene expression and constitute the foundation for pathological remodeling may be beneficial for developing new treatments for heart disease. These gene expression changes are largely preceded by epigenetic alterations to chromatin, including the post-translational modification of histones such as methylation, which alters chromatin to be more or less accessible for transcription factors or regulatory proteins to bind and modify gene expression. Methylation was once thought to be a permanent mark placed on histone or non-histone targets by methyltransferases, but is now understood to be a reversible process after the discovery of the first demethylase, KDM1A/LSD1. Since this time, it has been shown that demethylases play key roles in embryonic development, in maintaining cellular homeostasis and disease progression. However, the role of demethylases in the fetal and adult heart remains largely unknown. In this review, we have compiled data on the 33 mammalian demethylases that have been identified to date and evaluate their expression in the embryonic and adult heart as well as changes in expression in the failing myocardium using publicly available RNA-sequencing and proteomic datasets. Our analysis detected expression of 14 demethylases in the normal fetal heart, and 5 demethylases in the normal adult heart. Moreover, 8 demethylases displayed differential expression in the diseased human heart compared to healthy hearts. We then examined the literature regarding these demethylases and provide phenotypic information of 13 demethylases that have been functionally interrogated in some way in the heart. Lastly, we describe the 6 arginine and lysine residues on histones which have been shown to be methylated but have no corresponding demethylase identified which removes these methyl marks. Overall, this review highlights our current knowledge on the role of demethylases, their importance in cardiac development and pathophysiology and provides evidence for the use of pharmacological inhibitors to combat disease.


Assuntos
Insuficiência Cardíaca/enzimologia , Coração/crescimento & desenvolvimento , Histona Desmetilases com o Domínio Jumonji/metabolismo , Miocárdio/enzimologia , Adulto , Animais , Cromatina/genética , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina/genética , Inibidores Enzimáticos/uso terapêutico , Epigênese Genética , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/genética , Histonas/metabolismo , Humanos , Histona Desmetilases com o Domínio Jumonji/antagonistas & inibidores , Lisina/metabolismo , Metilação , Processamento de Proteína Pós-Traducional
5.
Proc Natl Acad Sci U S A ; 115(33): E7871-E7880, 2018 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-30061404

RESUMO

Smyd1, a muscle-specific histone methyltransferase, has established roles in skeletal and cardiac muscle development, but its role in the adult heart remains poorly understood. Our prior work demonstrated that cardiac-specific deletion of Smyd1 in adult mice (Smyd1-KO) leads to hypertrophy and heart failure. Here we show that down-regulation of mitochondrial energetics is an early event in these Smyd1-KO mice preceding the onset of structural abnormalities. This early impairment of mitochondrial energetics in Smyd1-KO mice is associated with a significant reduction in gene and protein expression of PGC-1α, PPARα, and RXRα, the master regulators of cardiac energetics. The effect of Smyd1 on PGC-1α was recapitulated in primary cultured rat ventricular myocytes, in which acute siRNA-mediated silencing of Smyd1 resulted in a greater than twofold decrease in PGC-1α expression without affecting that of PPARα or RXRα. In addition, enrichment of histone H3 lysine 4 trimethylation (a mark of gene activation) at the PGC-1α locus was markedly reduced in Smyd1-KO mice, and Smyd1-induced transcriptional activation of PGC-1α was confirmed by luciferase reporter assays. Functional confirmation of Smyd1's involvement showed an increase in mitochondrial respiration capacity induced by overexpression of Smyd1, which was abolished by siRNA-mediated PGC-1α knockdown. Conversely, overexpression of PGC-1α rescued transcript expression and mitochondrial respiration caused by silencing Smyd1 in cardiomyocytes. These findings provide functional evidence for a role of Smyd1, or any member of the Smyd family, in regulating cardiac energetics in the adult heart, which is mediated, at least in part, via modulating PGC-1α.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Metabolismo Energético/fisiologia , Histona-Lisina N-Metiltransferase/metabolismo , Mitocôndrias Cardíacas/metabolismo , Proteínas Musculares/metabolismo , Miocárdio/enzimologia , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/biossíntese , Fatores de Transcrição/metabolismo , Animais , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica , Histona Metiltransferases , Histona-Lisina N-Metiltransferase/genética , Camundongos , Camundongos Knockout , Mitocôndrias Cardíacas/genética , Proteínas Musculares/genética , PPAR alfa/biossíntese , PPAR alfa/genética , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Receptor X Retinoide alfa/biossíntese , Receptor X Retinoide alfa/genética , Fatores de Transcrição/genética
6.
Reprod Health ; 18(1): 17, 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33478528

RESUMO

INTRODUCTION: Intrauterine devices are the most effective long-acting reversible contraceptives, but in many developing countries, such as Jamaica, these devices remain underutilized. METHODS: A cross-sectional informative intervention was conducted among women ≥ 18 years of age attending postnatal clinics in western Jamaica from May to August 2018. Data were collected using an investigator-administered questionnaire/pre-test followed by a 12-slide PowerPoint® presentation and a post-test. RESULTS: Most of the 299 women who participated were 18-29 years of age, with a mean age of 27.1 (SD ± 6.1) years. Most had their first pregnancy between ages 18 and 24 years, with mean age at first pregnancy of 20.2 (SD ± 4.0) years. Only 3.0% of participants reported current use of an intrauterine device; 3.5% reported using an intrauterine device in the past. For nearly every measure of knowledge of intrauterine devices, there was a significant change in the proportion of participants who got the correct answer from the pre-test to the post-test. The mean summed pre-test knowledge score was 9.54 (SD ± 3.46) and the post-test score was 15.23 (SD ± 1.92); the possible total score is 18. The difference between the mean scores (5.69 points) was also significant. CONCLUSION: The intervention resulted in significant change in knowledge of intrauterine devices among the women and cleared up many misconceptions that may have contributed to reluctance of women to use intrauterine devices. Women of reproductive age in Jamaica should be counseled on contraceptive methods including intrauterine devices so that these devices can be considered in their contraceptive choices.


Assuntos
Comportamento Contraceptivo , Conhecimentos, Atitudes e Prática em Saúde , Dispositivos Intrauterinos/estatística & dados numéricos , Cuidado Pós-Natal , Adolescente , Adulto , Anticoncepção , Anticoncepcionais/uso terapêutico , Estudos Transversais , Feminino , Humanos , Dispositivos Intrauterinos/efeitos adversos , Jamaica , Período Pós-Parto , Gravidez , Adulto Jovem
7.
J Biol Chem ; 294(44): 16385-16399, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31530639

RESUMO

Bardet-Biedl syndrome (BBS) is a genetic disorder characterized by malfunctions in primary cilia resulting from mutations that disrupt the function of the BBSome, an 8-subunit complex that plays an important role in protein transport in primary cilia. To better understand the molecular basis of BBS, here we used an integrative structural modeling approach consisting of EM and chemical cross-linking coupled with MS analyses, to analyze the structure of a BBSome 2-7-9 subcomplex consisting of three homologous BBS proteins, BBS2, BBS7, and BBS9. The resulting molecular model revealed an overall structure that resembles a flattened triangle. We found that within this structure, BBS2 and BBS7 form a tight dimer through a coiled-coil interaction and that BBS9 associates with the dimer via an interaction with the α-helical domain of BBS2. Interestingly, a BBS-associated mutation of BBS2 (R632P) is located in its α-helical domain at the interface between BBS2 and BBS9, and binding experiments indicated that this mutation disrupts the BBS2-BBS9 interaction. This finding suggests that BBSome assembly is disrupted by the R632P substitution, providing molecular insights that may explain the etiology of BBS in individuals harboring this mutation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas do Citoesqueleto/metabolismo , Proteínas/metabolismo , Síndrome de Bardet-Biedl/metabolismo , Cílios/metabolismo , Células HEK293 , Humanos , Espectrometria de Massas/métodos , Microscopia Eletrônica/métodos , Modelos Moleculares , Mutação
8.
Am J Physiol Heart Circ Physiol ; 319(4): H847-H865, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32822544

RESUMO

Methyltransferases are a superfamily of enzymes that transfer methyl groups to proteins, nucleic acids, and small molecules. Traditionally, these enzymes have been shown to carry out a specific modification (mono-, di-, or trimethylation) on a single, or limited number of, amino acid(s). The largest subgroup of this family, protein methyltransferases, target arginine and lysine side chains of histone molecules to regulate gene expression. Although there is a large number of functional studies that have been performed on individual methyltransferases describing their methylation targets and effects on biological processes, no analyses exist describing the spatial distribution across tissues or their differential expression in the diseased heart. For this review, we performed tissue profiling in protein databases of 199 confirmed or putative methyltransferases to demonstrate the unique tissue-specific expression of these individual proteins. In addition, we examined transcript data sets from human heart failure patients and murine models of heart disease to identify 40 methyltransferases in humans and 15 in mice, which are differentially regulated in the heart, although many have never been functionally interrogated. Lastly, we focused our analysis on the largest subgroup, that of protein methyltransferases, and present a newly emerging phenomenon in which 16 of these enzymes have been shown to play dual roles in regulating transcription by maintaining the ability to both activate and repress transcription through methyltransferase-dependent or -independent mechanisms. Overall, this review highlights a novel paradigm shift in our understanding of the function of histone methyltransferases and correlates their expression in heart disease.


Assuntos
Epigênese Genética , Miocárdio/enzimologia , Proteínas Metiltransferases/metabolismo , Processamento de Proteína Pós-Traducional , Transcrição Gênica , Animais , Montagem e Desmontagem da Cromatina , Metilação de DNA , Cardiopatias/enzimologia , Cardiopatias/genética , Humanos , Metilação , Camundongos , Ativação Transcricional
9.
Nature ; 574(7780): 627-630, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31664214
10.
Proc Natl Acad Sci U S A ; 112(8): 2413-8, 2015 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-25675501

RESUMO

G-protein signaling depends on the ability of the individual subunits of the G-protein heterotrimer to assemble into a functional complex. Formation of the G-protein ßγ (Gßγ) dimer is particularly challenging because it is an obligate dimer in which the individual subunits are unstable on their own. Recent studies have revealed an intricate chaperone system that brings Gß and Gγ together. This system includes cytosolic chaperonin containing TCP-1 (CCT; also called TRiC) and its cochaperone phosducin-like protein 1 (PhLP1). Two key intermediates in the Gßγ assembly process, the Gß-CCT and the PhLP1-Gß-CCT complexes, were isolated and analyzed by a hybrid structural approach using cryo-electron microscopy, chemical cross-linking coupled with mass spectrometry, and unnatural amino acid cross-linking. The structures show that Gß interacts with CCT in a near-native state through interactions of the Gγ-binding region of Gß with the CCTγ subunit. PhLP1 binding stabilizes the Gß fold, disrupting interactions with CCT and releasing a PhLP1-Gß dimer for assembly with Gγ. This view provides unique insight into the interplay between CCT and a cochaperone to orchestrate the folding of a protein substrate.


Assuntos
Proteínas de Transporte/química , Chaperonina com TCP-1/química , Subunidades beta da Proteína de Ligação ao GTP/química , Subunidades gama da Proteína de Ligação ao GTP/química , Proteínas do Tecido Nervoso/química , Multimerização Proteica , Aminoácidos/metabolismo , Animais , Benzofenonas , Proteínas de Transporte/ultraestrutura , Chaperonina com TCP-1/ultraestrutura , Reagentes de Ligações Cruzadas/metabolismo , Microscopia Crioeletrônica , Subunidades beta da Proteína de Ligação ao GTP/ultraestrutura , Subunidades gama da Proteína de Ligação ao GTP/ultraestrutura , Humanos , Espectrometria de Massas , Modelos Moleculares , Proteínas do Tecido Nervoso/ultraestrutura , Fenilalanina/análogos & derivados , Estrutura Secundária de Proteína
11.
J Biol Chem ; 291(30): 15428-46, 2016 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-27226577

RESUMO

Transcriptome remodeling in heart disease occurs through the coordinated actions of transcription factors, histone modifications, and other chromatin features at pathology-associated genes. The extent to which genome-wide chromatin reorganization also contributes to the resultant changes in gene expression remains unknown. We examined the roles of two chromatin structural proteins, Ctcf (CCCTC-binding factor) and Hmgb2 (high mobility group protein B2), in regulating pathologic transcription and chromatin remodeling. Our data demonstrate a reciprocal relationship between Hmgb2 and Ctcf in controlling aspects of chromatin structure and gene expression. Both proteins regulate each others' expression as well as transcription in cardiac myocytes; however, only Hmgb2 does so in a manner that involves global reprogramming of chromatin accessibility. We demonstrate that the actions of Hmgb2 on local chromatin accessibility are conserved across genomic loci, whereas the effects on transcription are loci-dependent and emerge in concert with histone modification and other chromatin features. Finally, although both proteins share gene targets, Hmgb2 and Ctcf, neither binds these genes simultaneously nor do they physically colocalize in myocyte nuclei. Our study uncovers a previously unknown relationship between these two ubiquitous chromatin proteins and provides a mechanistic explanation for how Hmgb2 regulates gene expression and cellular phenotype. Furthermore, we provide direct evidence for structural remodeling of chromatin on a genome-wide scale in the setting of cardiac disease.


Assuntos
Cromatina/metabolismo , Regulação da Expressão Gênica/fisiologia , Proteína HMGB2/metabolismo , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , Proteínas Repressoras/metabolismo , Animais , Fator de Ligação a CCCTC , Cromatina/genética , Epigenômica , Feminino , Células HEK293 , Proteína HMGB2/genética , Células HeLa , Humanos , Camundongos , Proteínas Repressoras/genética
12.
Biochem J ; 473(19): 3355-69, 2016 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-27480105

RESUMO

Proper hematopoietic cell fate decisions require co-ordinated functions of transcription factors, their associated co-regulators, and histone-modifying enzymes. Growth factor independence 1 (GFI1) is a zinc finger transcriptional repressor and master regulator of normal and malignant hematopoiesis. While several GFI1-interacting proteins have been described, how GFI1 leverages these relationships to carry out transcriptional repression remains unclear. Here, we describe a functional axis involving GFI1, SMYD2, and LSD1 that is a critical contributor to GFI1-mediated transcriptional repression. SMYD2 methylates lysine-8 (K8) within a -(8)KSKK(11)- motif embedded in the GFI1 SNAG domain. Methylation-defective GFI1 SNAG domain lacks repressor function due to failure of LSD1 recruitment and persistence of promoter H3K4 di-methyl marks. Methylation-defective GFI1 also fails to complement GFI1 depletion phenotypes in developing zebrafish and lacks pro-growth and survival functions in lymphoid leukemia cells. Our data show a discrete methylation event in the GFI1 SNAG domain that facilitates recruitment of LSD1 to enable transcriptional repression and co-ordinate control of hematopoietic cell fate in both normal and malignant settings.


Assuntos
Proteínas de Ligação a DNA/fisiologia , Histona Desmetilases/metabolismo , Fatores de Transcrição/fisiologia , Transcrição Gênica/fisiologia , Sequência de Aminoácidos , Animais , Linhagem Celular , Linhagem da Célula , Metilação de DNA , Proteínas de Ligação a DNA/química , Humanos , Homologia de Sequência de Aminoácidos , Fatores de Transcrição/química , Peixe-Zebra
13.
PLoS Genet ; 10(3): e1004247, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24675841

RESUMO

TBX3 is a member of the T-box family of transcription factors with critical roles in development, oncogenesis, cell fate, and tissue homeostasis. TBX3 mutations in humans cause complex congenital malformations and Ulnar-mammary syndrome. Previous investigations into TBX3 function focused on its activity as a transcriptional repressor. We used an unbiased proteomic approach to identify TBX3 interacting proteins in vivo and discovered that TBX3 interacts with multiple mRNA splicing factors and RNA metabolic proteins. We discovered that TBX3 regulates alternative splicing in vivo and can promote or inhibit splicing depending on context and transcript. TBX3 associates with alternatively spliced mRNAs and binds RNA directly. TBX3 binds RNAs containing TBX binding motifs, and these motifs are required for regulation of splicing. Our study reveals that TBX3 mutations seen in humans with UMS disrupt its splicing regulatory function. The pleiotropic effects of TBX3 mutations in humans and mice likely result from disrupting at least two molecular functions of this protein: transcriptional regulation and pre-mRNA splicing.


Assuntos
Anormalidades Múltiplas/genética , Processamento Alternativo/genética , Doenças Mamárias/genética , Mapas de Interação de Proteínas/genética , Proteínas com Domínio T/genética , Ulna/anormalidades , Anormalidades Múltiplas/patologia , Animais , Doenças Mamárias/patologia , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Camundongos , Mutação , Malformações do Sistema Nervoso , Proteômica/métodos , Precursores de RNA/genética , RNA Mensageiro/genética , Proteínas com Domínio T/biossíntese , Ulna/patologia
14.
Lancet ; 385 Suppl 1: S19, 2015 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-26312841

RESUMO

BACKGROUND: Platelet-rich plasma (PRP), an autologous derivative of whole blood that contains a supraphysiological concentration of platelets, is thought to invoke an earlier and improved tissue healing response. This notion has been supported by in-vitro and animal studies in bone, cartilage, tendon, and muscle. To our knowledge no published study exists of the effects of PRP in human tissues in vivo. The aim of our study was to investigate the response of ruptured Achilles tendon treated with PRP. METHODS: Tendon tissue biopsy samples were obtained from 20 patients with ruptured Achilles tendon by means of ultrasound-guided needle biopsies from the healing area of the Achilles tendon 6 weeks after treatment with PRP or placebo controls (10 patients each). All samples were embedded in paraffin wax, sectioned, and stained with haematoxylin and eosin and alcian blue. Immunohistochemistry markers were used to identify collagen I and III, lymphocytes (CD45), proliferation (KI67), and blood vessels (CD34). All images were masked and analysed with Image J software. FINDINGS: Cellularity and glycosaminoglycans content were significantly higher in PRP-treated tendons than in controls (p=0·01 and p<0·001, respectively). Fibre structure of the tissue was significantly better in the PRP group than in the control tissue (p<0·001). Although both groups showed high collagen I staining, content of collagen I was significantly higher in PRP-treated tendons than in control tendons (p=0·0079), whereas collagen III content was not different (p=1·0). The ratio of collagen III to collagen I was significantly lower in PRP samples (p=0·007). There was no significant difference in CD45 expression (p=0·33). However, PRP samples had fewer blood vessels than did control samples (p=0·023). The overall modified Bonar score was significantly lower in PRP samples, which indicates improved early tendon healing. INTERPRETATION: This is the first study, to our knowledge, to report the immunohistochemical response of ruptured human Achilles tendon to PRP. The findings reveal that locally applied PRP enhanced the maturity of the healing tendon tissues by promoting better collagen I deposition, decreased cellularity, less vascularity, and higher glycosaminoglycan content when compared with control samples. Further work is required to determine the longer term effects of the use of PRP in musculoskeletal diseases. FUNDING: National Institute for Health Research.

15.
Am J Physiol Heart Circ Physiol ; 311(5): H1234-H1247, 2016 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-27663768

RESUMO

All terminally differentiated organs face two challenges, maintaining their cellular identity and restricting organ size. The molecular mechanisms responsible for these decisions are of critical importance to organismal development, and perturbations in their normal balance can lead to disease. A hallmark of heart failure, a condition affecting millions of people worldwide, is hypertrophic growth of cardiomyocytes. The various forms of heart failure in human and animal models share conserved transcriptome remodeling events that lead to expression of genes normally silenced in the healthy adult heart. However, the chromatin remodeling events that maintain cell and organ size are incompletely understood; insights into these mechanisms could provide new targets for heart failure therapy. Using a quantitative proteomics approach to identify muscle-specific chromatin regulators in a mouse model of hypertrophy and heart failure, we identified upregulation of the histone methyltransferase Smyd1 during disease. Inducible loss-of-function studies in vivo demonstrate that Smyd1 is responsible for restricting growth in the adult heart, with its absence leading to cellular hypertrophy, organ remodeling, and fulminate heart failure. Molecular studies reveal Smyd1 to be a muscle-specific regulator of gene expression and indicate that Smyd1 modulates expression of gene isoforms whose expression is associated with cardiac pathology. Importantly, activation of Smyd1 can prevent pathological cell growth. These findings have basic implications for our understanding of cardiac pathologies and open new avenues to the treatment of cardiac hypertrophy and failure by modulating Smyd1.


Assuntos
Cardiomegalia/genética , Montagem e Desmontagem da Cromatina/genética , Proteínas de Ligação a DNA/genética , Insuficiência Cardíaca/genética , Proteínas Musculares/genética , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , Fatores de Transcrição/genética , Animais , Western Blotting , Cardiomegalia/diagnóstico por imagem , Cardiomegalia/metabolismo , Crescimento Celular , Ecocardiografia , Regulação da Expressão Gênica , Técnicas de Introdução de Genes , Células HeLa , Insuficiência Cardíaca/diagnóstico por imagem , Insuficiência Cardíaca/metabolismo , Humanos , Camundongos , Camundongos Knockout , Miocárdio/patologia , Miócitos Cardíacos/patologia , Proteômica , RNA Mensageiro/metabolismo , Ratos , Reação em Cadeia da Polimerase em Tempo Real , Regulação para Cima , Remodelação Ventricular/genética
16.
Anesth Analg ; 122(4): 935-42, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26599794

RESUMO

BACKGROUND: Bleeding is a serious complication after pediatric cardiopulmonary bypass (CPB) that is associated with an increase in perioperative morbidity and mortality. Four-factor prothrombin complex concentrates (4F-PCCs) have been used off-label to supplement transfusion protocols for bleeding after CPB in adults; however, data on their use in neonates are limited. In this study, we hypothesized that 4F-PCCs administered ex vivo to neonatal plasma after CPB will increase thrombin generation. METHODS: Fifteen neonates undergoing complex cardiac repairs requiring CPB were enrolled in this prospective study. Arterial blood was obtained after anesthesia induction but before CPB (baseline), after CPB following heparin reversal, and after our standardized transfusion of a quarter of a platelet apheresis unit (approximately 20 mL·kg) and 3 units of cryoprecipitate. Kcentra (CSL Behring), a 4F-PCC with nonactivated factor VII (FVII), and factor 8 inhibitor bypassing activity (FEIBA; Baxter Healthcare Corporation), a 4F-PCC with activated FVII, were added ex vivo to plasma obtained after CPB to yield concentrations of 0.1 and 0.3 IU·mL. Calibrated automated thrombography was used to determine thrombin generation for each sample. RESULTS: The addition of Kcentra to plasma obtained after CPB resulted in a dose-dependent increase in the median (99% confidence interval) peak amount of thrombin generation (42.0 [28.7-50.7] nM for Kcentra 0.1 IU·mL and 113.9 [99.0-142.1] nM for Kcentra 0.3 IU·mL). The rate of thrombin generation was also increased (15.4 [6.5-24.6] nM·min for Kcentra 0.1 IU·mL and 48.6 [29.9-66.6] nM·min for Kcentra 0.3 IU·mL). The same was true for FEIBA (increase in peak: 39.8 [27.5-49.2] nM for FEIBA 0.1 IU·mL and 104.6 [92.7-124.4] nM for FEIBA 0.3 IU·mL; increase in rate: 17.4 [7.4-28.8] nM·min FEIBA 0.1 IU·mL and 50.5 [26.7- 63.1] nM·min FEIBA 0.3 IU·mL). In the posttransfusion samples, there was a significant increase with Kcentra in the median (99% confidence interval) peak amount (41.1 [21.0-59.7] nM for Kcentra 0.1 IU·mL and 126.8 [106.6- 137.9] nM for Kcentra 0.3 IU·mL) and rate (18.1 [-6.2 to 29.2] nM·min for Kcentra 0.1 IU·mL and 53.2 [28.2-83.1] nM·min for Kcentra 0.3 IU·mL) of thrombin generation. Again, the results were similar for FEIBA (increase in peak: 43.0 [36.4-56.7] nM for FEIBA 0.1 IU·mL and 109.2 [90.3-136.1] nM for FEIBA 0.3 IU·mL; increase in rate: 25.0 [9.1-32.6] nM·min for FEIBA 0.1 IU·mL and 59.7 [38.5-68.7] nM·min for FEIBA 0.3 IU·mL). However, FEIBA produced in a greater median reduction in lag time of thrombin generation versus Kcentra in samples obtained after CPB (P = 0.003 and P = 0.0002 for FEIBA versus Kcentra at 0.1 and 0.3 IU·mL, respectively) and in samples obtained after transfusion (P < 0.0001 for FEIBA versus Kcentra at 0.1 and 0.3 IU·mL). CONCLUSIONS: After CPB, thrombin generation in neonatal plasma was augmented by the addition of 4F-PCCs. The peak amount and rate of thrombin generation were enhanced in all conditions, whereas the lag time was shortened more with FEIBA. Our findings suggest that the use of 4F-PCCs containing activated FVII may be an effective adjunct to the initial transfusion of platelets and cryoprecipitate to augment coagulation and control bleeding in neonates after CPB.


Assuntos
Fatores de Coagulação Sanguínea/farmacologia , Ponte Cardiopulmonar/tendências , Plasma/efeitos dos fármacos , Plasma/metabolismo , Trombina/metabolismo , Ponte Cardiopulmonar/efeitos adversos , Feminino , Humanos , Recém-Nascido , Masculino , Estudos Prospectivos
18.
Mol Cell Proteomics ; 11(6): M111.014258, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22270000

RESUMO

A fundamental question in biology is how genome-wide changes in gene expression are enacted in response to a finite stimulus. Recent studies have mapped changes in nucleosome localization, determined the binding preferences for individual transcription factors, and shown that the genome adopts a nonrandom structure in vivo. What remains unclear is how global changes in the proteins bound to DNA alter chromatin structure and gene expression. We have addressed this question in the mouse heart, a system in which global gene expression and massive phenotypic changes occur without cardiac cell division, making the mechanisms of chromatin remodeling centrally important. To determine factors controlling genomic plasticity, we used mass spectrometry to measure chromatin-associated proteins. We have characterized the abundance of 305 chromatin-associated proteins in normal cells and measured changes in 108 proteins that accompany the progression of heart disease. These studies were conducted on a high mass accuracy instrument and confirmed in multiple biological replicates, facilitating statistical analysis and allowing us to interrogate the data bioinformatically for modules of proteins involved in similar processes. Our studies reveal general principles for global shifts in chromatin accessibility: altered linker to core histone ratio; differing abundance of chromatin structural proteins; and reprogrammed histone post-translational modifications. Using small interfering RNA-mediated loss-of-function in isolated cells, we demonstrate that the non-histone chromatin structural protein HMGB2 (but not HMGB1) suppresses pathologic cell growth in vivo and controls a gene expression program responsible for hypertrophic cell growth. Our findings reveal the basis for alterations in chromatin structure necessary for genome-wide changes in gene expression. These studies have fundamental implications for understanding how global chromatin remodeling occurs with specificity and accuracy, demonstrating that isoform-specific alterations in chromatin structural proteins can impart these features.


Assuntos
Cardiomegalia/metabolismo , Montagem e Desmontagem da Cromatina , Cromatina/metabolismo , Proteína HMGB2/metabolismo , Proteoma/metabolismo , Animais , Crescimento Celular , Análise por Conglomerados , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Proteína HMGB1/genética , Proteína HMGB1/metabolismo , Proteína HMGB2/genética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Miocárdio/metabolismo , Miocárdio/patologia , Interferência de RNA
19.
BMC Public Health ; 14: 1015, 2014 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-25266492

RESUMO

BACKGROUND: Smoking is a public health concern and an avoidable cause of morbidity and mortality. Widening tobacco control policies might help shift social norms, the acceptability of exposing others to second-hand smoke, and cultural attitudes towards smoking. This study explored patient, staff, and visitor viewpoints of smoking within the grounds of a National Health Service hospital. METHODS: Analysis of free text responses given as part of a larger repeat cross sectional questionnaire study. Free text qualitative responses analysed using thematic analysis. Pinderfields Hospital, a UK National Health Service hospital in the county of Yorkshire, provides a health service to around half a million people living in the Wakefield and North Kirklees area. Surveys were distributed 10th-18th September and 17th-21st December 2012. Of the n=952 participants who completed an anonymous survey n=306 participants provided a response to the optional free text question. RESULTS: Thematic analysis revealed 5 distinct themes: (1) smoking is a dirty problem; (2) smokers are free to do as they wish; (3) the poor smoker; (4) smoke in our space: the battleground; and (5) no smoking please. Of the n=272 represented by the five themes, generally people accepted that smoking is socially unacceptable but their understanding of smoking behaviours and attitudes towards management and control of smoking differed. There was a strong sense that action is needed to separate the space smokers and non-smokers share. We identified a distinct group of participants that supported a hard line approach and suggested enforcing the no smoking policy through fines and monitoring. CONCLUSIONS: Smoking on hospital grounds remains a contentious issue. Participants acknowledge that smoking is an increasingly unacceptable social behaviour but their understanding and acceptance of smokers vary. There is a strong sense of dislike about the impact of smoke and smokers on the shared hospital environment, with a focus on the hospital entrance. Participants suggest separating smokers and non-smokers and moving smokers away from the hospital entrance with the introduction of smoking shelters. These results suggest a complex narrative that should be investigated further to inform the implementation of the no-smoking policy across hospital settings.


Assuntos
Atitude Frente a Saúde , Pacientes Internados/estatística & dados numéricos , Recursos Humanos em Hospital/estatística & dados numéricos , Fumar/epidemiologia , Poluição por Fumaça de Tabaco/estatística & dados numéricos , Visitas a Pacientes/estatística & dados numéricos , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Pesquisa Qualitativa , Abandono do Hábito de Fumar/estatística & dados numéricos , Prevenção do Hábito de Fumar , Medicina Estatal/organização & administração , Inquéritos e Questionários , Reino Unido/epidemiologia
20.
Br J Sports Med ; 48(22): 1620-6, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24677026

RESUMO

BACKGROUND: Glucocorticoid injection (GCI) and surgical rotator cuff repair are two widely used treatments for rotator cuff tendinopathy. Little is known about the way in which medical and surgical treatments affect the human rotator cuff tendon in vivo. We assessed the histological and immunohistochemical effects of these common treatments on the rotator cuff tendon. STUDY DESIGN: Controlled laboratory study. METHODS: Supraspinatus tendon biopsies were taken before and after treatment from 12 patients undergoing GCI and 8 patients undergoing surgical rotator cuff repair. All patients were symptomatic and none of the patients undergoing local GCI had full thickness tears of the rotator cuff. The tendon tissue was then analysed using histological techniques and immunohistochemistry. RESULTS: There was a significant increase in nuclei count and vascularity after rotator cuff repair and not after GCI (both p=0.008). Hypoxia inducible factor 1α (HIF-1α) and cell proliferation were only increased after rotator cuff repair (both p=0.03) and not GCI. The ionotropic N-methyl-d-aspartate receptor 1 (NMDAR1) glutamate receptor was only increased after GCI and not rotator cuff repair (p=0.016). An increase in glutamate was seen in both groups following treatment (both p=0.04), while an increase in the receptor metabotropic glutamate receptor 7 (mGluR7) was only seen after rotator cuff repair (p=0.016). CONCLUSIONS: The increases in cell proliferation, vascularity and HIF-1α after surgical rotator cuff repair appear consistent with a proliferative healing response, and these features are not seen after GCI. The increase in the glutamate receptor NMDAR1 after GCI raises concerns about the potential excitotoxic tendon damage that may result from this common treatment.


Assuntos
Glucocorticoides/efeitos adversos , Manguito Rotador/cirurgia , Tendinopatia/induzido quimicamente , Traumatismos dos Tendões/terapia , Adulto , Idoso , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/efeitos adversos , Traumatismos em Atletas/terapia , Estudos de Casos e Controles , Proliferação de Células/fisiologia , Feminino , Glucocorticoides/administração & dosagem , Ácido Glutâmico/metabolismo , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Biópsia Guiada por Imagem , Imuno-Histoquímica , Injeções Intra-Articulares , Masculino , Metilprednisolona/administração & dosagem , Metilprednisolona/efeitos adversos , Metilprednisolona/análogos & derivados , Acetato de Metilprednisolona , Pessoa de Meia-Idade , Proteínas do Tecido Nervoso/metabolismo , Variações Dependentes do Observador , Receptores de N-Metil-D-Aspartato/metabolismo , Manguito Rotador/patologia , Lesões do Manguito Rotador , Dor de Ombro/terapia , Tendinopatia/patologia , Ultrassonografia de Intervenção , Cicatrização/fisiologia
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