Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Crit Care Med ; 45(4): e399-e408, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27648519

RESUMO

OBJECTIVES: Sepsis is associated with cardiac contractile dysfunction attributed to alterations in Ca handling. We examined the subcellular mechanisms involved in sarcoplasmic reticulum Ca loss that mediate altered Ca handling and contractile dysfunction associated with sepsis. DESIGN: Randomized controlled trial. SETTING: Research laboratorySUBJECTS:: Male wild type and transgenic miceINTERVENTIONS:: We induced sepsis in mice using the colon ascendens stent peritonitis model. MEASUREMENTS AND MAIN RESULTS: Twenty-four hours after colon ascendens stent peritonitis surgery, we observed that wild type mice had significantly elevated proinflammatory cytokine levels, reduced ejection fraction, and fractional shortening (ejection fraction %, 54.76 ± 0.67; fractional shortening %, 27.53 ± 0.50) compared with sham controls (ejection fraction %, 73.57 ± 0.20; fractional shortening %, 46.75 ± 0.38). At the cardiac myocyte level, colon ascendens stent peritonitis cells showed reduced cell shortening, Ca transient amplitude and sarcoplasmic reticulum Ca content compared with sham cardiomyocytes. Colon ascendens stent peritonitis hearts showed a significant increase in oxidation-dependent calcium and calmodulin-dependent protein kinase II activity, which could be prevented by pretreating animals with the antioxidant tempol. Pharmacologic inhibition of calcium and calmodulin-dependent protein kinase II with 2.5 µM of KN93 prevented the decrease in cell shortening, Ca transient amplitude, and sarcoplasmic reticulum Ca content in colon ascendens stent peritonitis myocytes. Contractile function was also preserved in colon ascendens stent peritonitis myocytes isolated from transgenic mice expressing a calcium and calmodulin-dependent protein kinase II inhibitory peptide (AC3-I) and in colon ascendens stent peritonitis myocytes isolated from mutant mice that have the ryanodine receptor 2 calcium and calmodulin-dependent protein kinase II-dependent phosphorylation site (serine 2814) mutated to alanine (S2814A). Furthermore, colon ascendens stent peritonitis S2814A mice showed preserved ejection fraction and fractional shortening (ejection fraction %, 73.06 ± 6.31; fractional shortening %, 42.33 ± 5.70) compared with sham S2814A mice (ejection fraction %, 71.60 ± 4.02; fractional shortening %, 39.63 ± 3.23). CONCLUSIONS: Results indicate that oxidation and subsequent activation of calcium and calmodulin-dependent protein kinase II has a causal role in the contractile dysfunction associated with sepsis. Calcium and calmodulin-dependent protein kinase II, through phosphorylation of the ryanodine receptor would lead to Ca leak from the sarcoplasmic reticulum, reducing sarcoplasmic reticulum Ca content, Ca transient amplitude and contractility. Development of organ-specific calcium and calmodulin-dependent protein kinase II inhibitors may result in a beneficial therapeutic strategy to ameliorate contractile dysfunction associated with sepsis.


Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Cálcio/metabolismo , Contração Miocárdica/fisiologia , Miócitos Cardíacos/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Sepse/metabolismo , Sepse/fisiopatologia , Animais , Antioxidantes/farmacologia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/antagonistas & inibidores , Óxidos N-Cíclicos/farmacologia , Masculino , Camundongos , Camundongos Transgênicos , Contração Miocárdica/efeitos dos fármacos , Contração Miocárdica/genética , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/patologia , Oxirredução/efeitos dos fármacos , Peptídeos/metabolismo , Fosforilação/efeitos dos fármacos , Fosforilação/genética , Inibidores de Proteínas Quinases/farmacologia , Distribuição Aleatória , Espécies Reativas de Oxigênio/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Retículo Sarcoplasmático/metabolismo , Sepse/genética , Marcadores de Spin , Volume Sistólico/efeitos dos fármacos , Volume Sistólico/genética
2.
Front Physiol ; 13: 1007418, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36505085

RESUMO

Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare genetic disorder that causes accelerated aging and a high risk of cardiovascular complications. However, the underlying mechanisms of cardiac complications of this syndrome are not fully understood. This study modeled HGPS using cardiomyocytes (CM) derived from induced pluripotent stem cells (iPSC) derived from a patient with HGPS and characterized the biophysical, morphological, and molecular changes found in these CM compared to CM derived from a healthy donor. Electrophysiological recordings suggest that the HGPS-CM was functional and had normal electrophysiological properties. Electron tomography showed nuclear morphology alteration, and the 3D reconstruction of electron tomography images suggests structural abnormalities in HGPS-CM mitochondria, however, there was no difference in mitochondrial content as measured by Mitotracker. Immunofluorescence indicates nuclear morphological alteration and confirms the presence of Troponin T. Telomere length was measured using qRT-PCR, and no difference was found in the CM from HGPS when compared to the control. Proteomic analysis was carried out in a high-resolution system using Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS). The proteomics data show distinct group separations and protein expression differences between HGPS and control-CM, highlighting changes in ribosomal, TCA cycle, and amino acid biosynthesis, among other modifications. Our findings show that iPSC-derived cardiomyocytes from a Progeria Syndrome patient have significant changes in mitochondrial morphology and protein expression, implying novel mechanisms underlying premature cardiac aging.

3.
Front Pharmacol ; 12: 641116, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33912054

RESUMO

Heart failure has reached epidemic proportions with the advances in cardiovascular therapies for ischemic heart diseases and the progressive aging of the world population. Efficient pharmacological therapies are available for treating heart failure, but unfortunately, even with optimized therapy, prognosis is often poor. Their last therapeutic option is, therefore, a heart transplantation with limited organ supply and complications related to immunosuppression. In this setting, cell therapies have emerged as an alternative. Many clinical trials have now been performed using different cell types and injection routes. In this perspective, we will analyze the results of such trials and discuss future perspectives for cell therapies as an efficacious treatment of heart failure.

4.
Cells ; 8(7)2019 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-31336746

RESUMO

Omics approaches have significantly impacted knowledge about molecular signaling pathways driving cell function. Induced pluripotent stem cells (iPSC) have revolutionized the field of biological sciences and proteomics and, in particular, has been instrumental in identifying key elements operating during the maintenance of the pluripotent state and the differentiation process to the diverse cell types that form organisms. This review covers the evolution of conceptual and methodological strategies in proteomics; briefly describes the generation of iPSC from a historical perspective, the state-of-the-art of iPSC-based proteomics; and compares data on the proteome and transcriptome of iPSC to that of embryonic stem cells (ESC). Finally, proteomics of healthy and diseased cells and organoids differentiated from iPSC are analyzed.


Assuntos
Células-Tronco Pluripotentes Induzidas , Proteoma/metabolismo , Proteômica/métodos , Transcriptoma , Diferenciação Celular , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo
5.
Sci Rep ; 9(1): 18077, 2019 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-31792288

RESUMO

The stem cell niche has a strong influence in the differentiation potential of human pluripotent stem cells with integrins playing a major role in communicating cells with the extracellular environment. However, it is not well understood how interactions between integrins and the extracellular matrix are involved in cardiac stem cell differentiation. To evaluate this, we performed a profile of integrins expression in two stages of cardiac differentiation: mesodermal progenitors and cardiomyocytes. We found an active regulation of the expression of different integrins during cardiac differentiation. In particular, integrin α5 subunit showed an increased expression in mesodermal progenitors, and a significant downregulation in cardiomyocytes. To analyze the effect of α5 subunit, we modified its expression by using a CRISPRi technique. After its downregulation, a significant impairment in the process of epithelial-to-mesenchymal transition was seen. Early mesoderm development was significantly affected due to a downregulation of key genes such as T Brachyury and TBX6. Furthermore, we observed that repression of integrin α5 during early stages led to a reduction in cardiomyocyte differentiation and impaired contractility. In summary, our results showed the link between changes in cell identity with the regulation of integrin α5 expression through the alteration of early stages of mesoderm commitment.


Assuntos
Células-Tronco Embrionárias Humanas/citologia , Integrina alfa5/genética , Miócitos Cardíacos/citologia , Sistemas CRISPR-Cas , Diferenciação Celular , Linhagem Celular , Regulação para Baixo , Regulação da Expressão Gênica no Desenvolvimento , Células HEK293 , Células-Tronco Embrionárias Humanas/metabolismo , Humanos , Miócitos Cardíacos/metabolismo , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/metabolismo , Nicho de Células-Tronco
6.
EBioMedicine ; 16: 224-237, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28163043

RESUMO

p53 is an important modulator of stem cell fate, but its role in cardiac progenitor cells (CPCs) is unknown. Here, we tested the effects of a single extra-copy of p53 on the function of CPCs in the presence of oxidative stress mediated by doxorubicin in vitro and type-1 diabetes in vivo. CPCs were obtained from super-p53 transgenic mice (p53-tg), in which the additional allele is regulated in a manner similar to the endogenous protein. Old CPCs with increased p53 dosage showed a superior ability to sustain oxidative stress, repair DNA damage and restore cell division. With doxorubicin, a larger fraction of CPCs carrying an extra-copy of the p53 allele recruited γH2A.X reestablishing DNA integrity. Enhanced p53 expression resulted in a superior tolerance to oxidative stress in vivo by providing CPCs with defense mechanisms necessary to survive in the milieu of the diabetic heart; they engrafted in regions of tissue injury and in three days acquired the cardiomyocyte phenotype. The biological advantage provided by the increased dosage of p53 in CPCs suggests that this genetic strategy may be translated to humans to increase cellular engraftment and growth, critical determinants of successful cell therapy for the failing heart.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , Células-Tronco/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Western Blotting , Diferenciação Celular/genética , Proliferação de Células/genética , Células Cultivadas , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/metabolismo , Feminino , Expressão Gênica , Coração/fisiopatologia , Histonas/metabolismo , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microscopia de Fluorescência , Miócitos Cardíacos/citologia , Miócitos Cardíacos/transplante , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transplante de Células-Tronco/métodos , Células-Tronco/citologia , Proteína Supressora de Tumor p53/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA