RESUMO
Scar tissue size following myocardial infarction is an independent predictor of cardiovascular outcomes, yet little is known about factors regulating scar size. We demonstrate that collagen V, a minor constituent of heart scars, regulates the size of heart scars after ischemic injury. Depletion of collagen V led to a paradoxical increase in post-infarction scar size with worsening of heart function. A systems genetics approach across 100 in-bred strains of mice demonstrated that collagen V is a critical driver of postinjury heart function. We show that collagen V deficiency alters the mechanical properties of scar tissue, and altered reciprocal feedback between matrix and cells induces expression of mechanosensitive integrins that drive fibroblast activation and increase scar size. Cilengitide, an inhibitor of specific integrins, rescues the phenotype of increased post-injury scarring in collagen-V-deficient mice. These observations demonstrate that collagen V regulates scar size in an integrin-dependent manner.
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Cicatriz/metabolismo , Colágeno Tipo V/deficiência , Colágeno Tipo V/metabolismo , Traumatismos Cardíacos/metabolismo , Contração Miocárdica/genética , Miofibroblastos/metabolismo , Animais , Cicatriz/genética , Cicatriz/fisiopatologia , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Cadeia alfa 1 do Colágeno Tipo I , Colágeno Tipo III/genética , Colágeno Tipo III/metabolismo , Colágeno Tipo V/genética , Matriz Extracelular/genética , Matriz Extracelular/metabolismo , Feminino , Fibrose/genética , Fibrose/metabolismo , Regulação da Expressão Gênica/genética , Integrinas/antagonistas & inibidores , Integrinas/genética , Integrinas/metabolismo , Isoproterenol/farmacologia , Masculino , Mecanotransdução Celular/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microscopia de Força Atômica/instrumentação , Microscopia Eletrônica de Transmissão , Contração Miocárdica/efeitos dos fármacos , Miofibroblastos/citologia , Miofibroblastos/patologia , Miofibroblastos/ultraestrutura , Análise de Componente Principal , Proteômica , RNA-Seq , Análise de Célula ÚnicaRESUMO
Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), responsible for the Coronavirus Disease 2019 (COVID-19) pandemic, causes respiratory failure and damage to multiple organ systems. The emergence of viral variants poses a risk of vaccine failures and prolongation of the pandemic. However, our understanding of the molecular basis of SARS-CoV-2 infection and subsequent COVID-19 pathophysiology is limited. In this study, we have uncovered a critical role for the evolutionarily conserved Hippo signaling pathway in COVID-19 pathogenesis. Given the complexity of COVID-19-associated cell injury and immunopathogenesis processes, we investigated Hippo pathway dynamics in SARS-CoV-2 infection by utilizing COVID-19 lung samples and human cell models based on pluripotent stem cell-derived cardiomyocytes (PSC-CMs) and human primary lung air-liquid interface (ALI) cultures. SARS-CoV-2 infection caused activation of the Hippo signaling pathway in COVID-19 lung and in vitro cultures. Both parental and Delta variant of concern (VOC) strains induced Hippo pathway. The chemical inhibition and gene knockdown of upstream kinases MST1/2 and LATS1 resulted in significantly enhanced SARS-CoV-2 replication, indicating antiviral roles. Verteporfin, a pharmacological inhibitor of the Hippo pathway downstream transactivator, YAP, significantly reduced virus replication. These results delineate a direct antiviral role for Hippo signaling in SARS-CoV-2 infection and the potential for this pathway to be pharmacologically targeted to treat COVID-19.
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COVID-19 , Humanos , SARS-CoV-2 , Via de Sinalização Hippo , Antivirais/farmacologiaRESUMO
Individuals with features of metabolic syndrome are particularly susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus associated with the severe respiratory disease, coronavirus disease 2019 (COVID-19). Despite considerable attention dedicated to COVID-19, the link between metabolic syndrome and SARS-CoV-2 infection remains unclear. Using data from the UK Biobank, we investigated the relationship between severity of COVID-19 and metabolic syndrome-related serum biomarkers measured prior to SARS-CoV-2 infection. Logistic regression analyses were used to test biomarker levels and biomarker-associated genetic variants with SARS-CoV-2-related outcomes. Among SARS-CoV-2-positive cases and negative controls, a 10 mg/dl increase in serum HDL-cholesterol or apolipoprotein A1 levels was associated with â¼10% reduced risk of SARS-CoV-2 infection, after adjustment for age, sex, obesity, hypertension, type 2 diabetes, and coronary artery disease. Evaluation of known genetic variants for HDL-cholesterol revealed that individuals homozygous for apolipoprotein E4 alleles had â¼2- to 3-fold higher risk of SARS-CoV-2 infection or mortality from COVID-19 compared with apolipoprotein E3 homozygotes, even after adjustment for HDL-cholesterol levels. However, cumulative effects of all evaluated HDL-cholesterol-raising alleles and Mendelian randomization analyses did not reveal association of genetically higher HDL-cholesterol levels with decreased risk of SARS-CoV-2 infection. These results implicate serum HDL-cholesterol and apolipoprotein A1 levels measured prior to SAR-CoV-2 exposure as clinical risk factors for severe COVID-19 infection but do not provide evidence that genetically elevated HDL-cholesterol levels are associated with SAR-CoV-2 infection.
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Apolipoproteína A-I , COVID-19 , HDL-Colesterol , Homozigoto , Síndrome Metabólica , SARS-CoV-2/metabolismo , Adulto , Idoso , Apolipoproteína A-I/sangue , Apolipoproteína A-I/genética , Biomarcadores/sangue , COVID-19/sangue , COVID-19/genética , COVID-19/mortalidade , HDL-Colesterol/sangue , HDL-Colesterol/genética , Feminino , Humanos , Masculino , Síndrome Metabólica/sangue , Síndrome Metabólica/genética , Síndrome Metabólica/mortalidade , Pessoa de Meia-Idade , Gravidade do Paciente , Reino Unido/epidemiologiaRESUMO
WNT signaling is an elaborate and complex collection of signal transduction pathways mediated by multiple signaling molecules. WNT signaling is critically important for developmental processes, including cell proliferation, differentiation and tissue patterning. Little WNT signaling activity is present in the cardiovascular system of healthy adults, but reactivation of the pathway is observed in many pathologies of heart and blood vessels. The high prevalence of these pathologies and their significant contribution to human disease burden has raised interest in WNT signaling as a potential target for therapeutic intervention. In this review, we first will focus on the constituents of the pathway and their regulation and the different signaling routes. Subsequently, the role of WNT signaling in cardiovascular development is addressed, followed by a detailed discussion of its involvement in vascular and cardiac disease. After highlighting the crosstalk between WNT, transforming growth factor-ß and angiotensin II signaling, and the emerging role of WNT signaling in the regulation of stem cells, we provide an overview of drugs targeting the pathway at different levels. From the combined studies we conclude that, despite the sometimes conflicting experimental data, a general picture is emerging that excessive stimulation of WNT signaling adversely affects cardiovascular pathology. The rapidly increasing collection of drugs interfering at different levels of WNT signaling will allow the evaluation of therapeutic interventions in the pathway in relevant animal models of cardiovascular diseases and eventually in patients in the near future, translating the outcomes of the many preclinical studies into a clinically relevant context.
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Doenças Cardiovasculares/metabolismo , Via de Sinalização Wnt/fisiologia , Animais , Doenças Cardiovasculares/tratamento farmacológico , Humanos , Terapia de Alvo Molecular , Via de Sinalização Wnt/efeitos dos fármacosRESUMO
RATIONALE: Cardiac fibroblasts do not form a syncytium but reside in the interstitium between myocytes. This topological relationship between fibroblasts and myocytes is maintained throughout postnatal life until an acute myocardial injury occurs, when fibroblasts are recruited to, proliferate and aggregate in the region of myocyte necrosis. The accumulation or aggregation of fibroblasts in the area of injury thus represents a unique event in the life cycle of the fibroblast, but little is known about how changes in the topological arrangement of fibroblasts after cardiac injury affect fibroblast function. OBJECTIVE: The objective of the study was to investigate how changes in topological states of cardiac fibroblasts (such as after cardiac injury) affect cellular phenotype. METHODS AND RESULTS: Using 2 and 3-dimensional (2D versus 3D) culture conditions, we show that simple aggregation of cardiac fibroblasts is sufficient by itself to induce genome-wide changes in gene expression and chromatin remodeling. Remarkably, gene expression changes are reversible after the transition from a 3D back to 2D state demonstrating a topological regulation of cellular plasticity. Genes induced by fibroblast aggregation are strongly associated and predictive of adverse cardiac outcomes and remodeling in mouse models of cardiac hypertrophy and failure. Using solvent-based tissue clearing techniques to create optically transparent cardiac scar tissue, we show that fibroblasts in the region of dense scar tissue express markers that are induced by fibroblasts in the 3D conformation. Finally, using live cell interferometry, a quantitative phase microscopy technique to detect absolute changes in single cell biomass, we demonstrate that conditioned medium collected from fibroblasts in 3D conformation compared with that from a 2D state significantly increases cardiomyocyte cell hypertrophy. CONCLUSIONS: Taken together, these findings demonstrate that simple topological changes in cardiac fibroblast organization are sufficient to induce chromatin remodeling and global changes in gene expression with potential functional consequences for the healing heart.
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Agregação Celular , Plasticidade Celular , Montagem e Desmontagem da Cromatina , Fibroblastos/patologia , Expressão Gênica , Infarto do Miocárdio/patologia , Miocárdio/patologia , Animais , Técnicas de Cultura de Células , Meios de Cultivo Condicionados , Feminino , Fibroblastos/fisiologia , Masculino , Camundongos , Miócitos Cardíacos/citologia , Miócitos Cardíacos/fisiologia , FenótipoRESUMO
INTRODUCTION: The periosteum has a bilayered structure that surrounds cortical bone. The outer layer is rich in connective tissue and fibroblasts, while the inner layer in contact with the cortical surface of the bone predominantly consists of osteoblasts and osteoblast progenitors. The identification of cell-specific surface markers of the bilayered structure of the periosteum is important for the purpose of tissue regeneration. MATERIALS AND METHODS: We investigated the expression of the discoidin domain tyrosine kinase receptor DDR2, fibroblast specific protein-1 (FSP-1) and alkaline phosphatase (ALP) in the periosteum of cortical bone by immunohistochemistry. Osteogenic differentiation was compared between DDR2- and FSP-1-expressing cells flow-sorted from the periosteum. RESULTS: We showed that DDR2 predominantly labeled osteogenic cells residing in the inner layer of the periosteum and that Pearson's coefficient of colocalization indicated a significant correlation with the expression of ALP. The mineralization of DDR2-expressing osteogenic cells isolated from the periosteum was significantly induced. In contrast, FSP-1 predominantly labeled the outer layer of periosteal fibroblasts, and Pearson's coefficient of colocalization indicated that FSP-1 was poorly correlated with the expression of DDR2 and ALP. FSP-1-expressing periosteal fibroblasts did not exhibit osteogenic differentiation for the induction of bone mineralization. CONCLUSION: DDR2 is a novel potential cell surface marker for identifying and isolating osteoblasts and osteoblast progenitors within the periosteum that can be used for musculoskeletal regenerative therapies.
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Receptores com Domínio Discoidina/metabolismo , Osteoblastos/citologia , Osteoblastos/metabolismo , Periósteo/citologia , Fosfatase Alcalina/metabolismo , Animais , Biomarcadores/metabolismo , Calcificação Fisiológica , Diferenciação Celular , Camundongos Endogâmicos C57BL , Osteogênese , Proteína A4 de Ligação a Cálcio da Família S100/metabolismoRESUMO
Endothelial cells contribute to a subset of cardiac fibroblasts by undergoing endothelial-to-mesenchymal transition, but whether cardiac fibroblasts can adopt an endothelial cell fate and directly contribute to neovascularization after cardiac injury is not known. Here, using genetic fate map techniques, we demonstrate that cardiac fibroblasts rapidly adopt an endothelial-cell-like phenotype after acute ischaemic cardiac injury. Fibroblast-derived endothelial cells exhibit anatomical and functional characteristics of native endothelial cells. We show that the transcription factor p53 regulates such a switch in cardiac fibroblast fate. Loss of p53 in cardiac fibroblasts severely decreases the formation of fibroblast-derived endothelial cells, reduces post-infarct vascular density and worsens cardiac function. Conversely, stimulation of the p53 pathway in cardiac fibroblasts augments mesenchymal-to-endothelial transition, enhances vascularity and improves cardiac function. These observations demonstrate that mesenchymal-to-endothelial transition contributes to neovascularization of the injured heart and represents a potential therapeutic target for enhancing cardiac repair.
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Transdiferenciação Celular , Vasos Coronários/citologia , Vasos Coronários/crescimento & desenvolvimento , Células Endoteliais/citologia , Mesoderma/citologia , Isquemia Miocárdica/patologia , Neovascularização Fisiológica , Animais , Feminino , Fibroblastos/citologia , Técnicas In Vitro , Masculino , Camundongos , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoAssuntos
Adipogenia , Osteogênese , Fator de Células-Tronco , Células-Tronco , Fatores de TranscriçãoRESUMO
Cardiac failure has been widely associated with an increase in glucose utilization. The aim of our study was to identify factors that mechanistically bridge this link between hyperglycemia and heart failure. Here, we screened the Hybrid Mouse Diversity Panel (HMDP) for substrate-specific cardiomyocyte candidates based on heart transcriptional profile and circulating nutrients. Next, we utilized an in vitro model of rat cardiomyocytes to demonstrate that the gene expression changes were in direct response to substrate abundance. After overlaying candidates of interest with a separate HMDP study evaluating isoproterenol-induced heart failure, we chose to focus on the gene Trp53inp2 as a cardiomyocyte glucose utilization-specific factor. Trp53inp2 gene knockdown in rat cardiomyocytes reduced expression and protein abundance of key glycolytic enzymes. This resulted in reduction of both glucose uptake and glycogen content in cardiomyocytes stimulated with isoproterenol. Furthermore, this reduction effectively blunted the capacity of glucose and isoprotereonol to synergistically induce hypertrophic gene expression and cell size expansion. We conclude that Trp53inp2 serves as regulator of cardiomyocyte glycolytic activity and can consequently regulate hypertrophic response in the context of elevated glucose content.NEW & NOTEWORTHY Here, we apply a novel method for screening transcripts based on a substrate-specific expression pattern to identify Trp53inp2 as an induced cardiomyocyte glucose utilization factor. We further show that reducing expression of the gene could effectively blunt hypertrophic response in the context of elevated glucose content.
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Cardiomegalia/genética , Cardiomegalia/metabolismo , Glucose/metabolismo , Miócitos Cardíacos/metabolismo , Fatores de Transcrição/genética , Animais , Cardiomegalia/induzido quimicamente , Cardiotônicos , Tamanho Celular , Células Cultivadas , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Glicogênio/metabolismo , Glicólise/genética , Técnicas In Vitro , Isoproterenol , Camundongos , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/patologia , RNA Interferente Pequeno , Ratos , Especificidade por SubstratoRESUMO
Wnts are required for cardiogenesis but the role of specific Wnts in cardiac repair remains unknown. In this report, we show that a dynamic Wnt1/ßcatenin injury response activates the epicardium and cardiac fibroblasts to promote cardiac repair. Acute ischaemic cardiac injury upregulates Wnt1 that is initially expressed in the epicardium and subsequently by cardiac fibroblasts in the region of injury. Following cardiac injury, the epicardium is activated organ-wide in a Wnt-dependent manner, expands, undergoes epithelial-mesenchymal transition (EMT) to generate cardiac fibroblasts, which localize in the subepicardial space. The injured regions in the heart are Wnt responsive as well and Wnt1 induces cardiac fibroblasts to proliferate and express pro-fibrotic genes. Disruption of downstream Wnt signalling in epicardial cells decreases epicardial expansion, EMT and leads to impaired cardiac function and ventricular dilatation after cardiac injury. Furthermore, disruption of Wnt/ßcatenin signalling in cardiac fibroblasts impairs wound healing and decreases cardiac performance as well. These findings reveal that a pro-fibrotic Wnt1/ßcatenin injury response is critically required for preserving cardiac function after acute ischaemic cardiac injury.
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Fibroblastos/metabolismo , Coração/fisiologia , Infarto do Miocárdio/patologia , Pericárdio/metabolismo , Regeneração/fisiologia , Transdução de Sinais/fisiologia , Proteína Wnt1/fisiologia , beta Catenina/fisiologia , Animais , Divisão Celular , Transição Epitelial-Mesenquimal , Fibrose , Regulação da Expressão Gênica , Hibridização In Situ , Camundongos , Camundongos Transgênicos , Infarto do Miocárdio/genética , Infarto do Miocárdio/metabolismo , Pericárdio/patologia , RNA Interferente Pequeno/farmacologia , Proteínas Recombinantes de Fusão/fisiologia , Regulação para Cima , Proteína Wnt1/biossíntese , Proteína Wnt1/genética , Cicatrização/fisiologiaRESUMO
Cardiac fibroblasts are the most abundant cell type in the mammalian heart and comprise approximately two-thirds of the total number of cardiac cell types. During development, epicardial cells undergo epithelial-mesenchymal-transition to generate cardiac fibroblasts that subsequently migrate into the developing myocardium to become resident cardiac fibroblasts. Fibroblasts form a structural scaffold for the attachment of cardiac cell types during development, express growth factors and cytokines and regulate proliferation of embryonic cardiomyocytes. In post natal life, cardiac fibroblasts play a critical role in orchestrating an injury response. Fibroblast activation and proliferation early after cardiac injury are critical for maintaining cardiac integrity and function, while the persistence of fibroblasts long after injury leads to chronic scarring and adverse ventricular remodeling. In this review, we discuss the physiologic function of the fibroblast during cardiac development and wound healing, molecular mediators of activation that could be possible targets for drug development for fibrosis and finally the use of reprogramming technologies for reversing scar. This article is part of a Special Issue entitled "Myocyte-Fibroblast Signalling in Myocardium."
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Fibroblastos/citologia , Mecanotransdução Celular , Cicatrização/fisiologia , Cicatriz/patologia , Cicatriz/fisiopatologia , Citocinas/biossíntese , Matriz Extracelular/química , Matriz Extracelular/metabolismo , Fibroblastos/metabolismo , Coração/embriologia , Coração/fisiologia , Coração/fisiopatologia , Traumatismos Cardíacos/patologia , Traumatismos Cardíacos/fisiopatologia , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/biossíntese , Neovascularização FisiológicaRESUMO
Mapping cellular activities over large areas is crucial for understanding the collective behaviors of multicellular systems. Biomechanical properties, such as cellular traction force, serve as critical regulators of physiological states and molecular configurations. However, existing technologies for mapping large-area biomechanical dynamics are limited by the small field of view and scanning nature. To address this, we propose a novel platform that utilizes a vast number of optical diffractive elements for mapping large-area biomechanical dynamics. This platform achieves a field-of-view of 10.6 mm X 10.6 mm, a three-orders-of-magnitude improvement over traditional traction force microscopy. Transient mechanical waves generated by monolayer neonatal rat ventricular myocytes were captured with high spatiotemporal resolution (130 fps and 20 µm for temporal and spatial resolution, respectively). Furthermore, its label-free nature allows for long-term observations extended to a week, with minimal disruption of cellular functions. Finally, simultaneous measurements of calcium ions concentrations and biomechanical dynamics are demonstrated.
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AIMS: Following myocardial infarction (MI), the heart repairs itself via a fibrotic repair response. The degree of fibrosis is determined by the balance between deposition of extracellular matrix (ECM) by activated fibroblasts and breakdown of nascent scar tissue by proteases that are secreted predominantly by inflammatory cells. Excessive proteolytic activity and matrix turnover has been observed in human heart failure, and protease inhibitors in the injured heart regulate matrix breakdown. Serine protease inhibitors (Serpins) represent the largest and the most functionally diverse family of evolutionary conserved protease inhibitors, and levels of the specific Serpin, SerpinA3, have been strongly associated with clinical outcomes in human MI as well as non-ischaemic cardiomyopathies. Yet, the role of Serpins in regulating cardiac remodelling is poorly understood. The aim of this study was to understand the role of Serpins in regulating scar formation after MI. METHODS AND RESULTS: Using a SerpinA3n conditional knockout mice model, we observed the robust expression of Serpins in the infarcted murine heart and demonstrate that genetic deletion of SerpinA3n (mouse homologue of SerpinA3) leads to increased activity of substrate proteases, poorly compacted matrix, and significantly worse post-infarct cardiac function. Single-cell transcriptomics complemented with histology in SerpinA3n-deficient animals demonstrated increased inflammation, adverse myocyte hypertrophy, and expression of pro-hypertrophic genes. Proteomic analysis of scar tissue demonstrated decreased cross-linking of ECM peptides consistent with increased proteolysis in SerpinA3n-deficient animals. CONCLUSION: Our study demonstrates a hitherto unappreciated causal role of Serpins in regulating matrix function and post-infarct cardiac remodelling.
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Modelos Animais de Doenças , Fibrose , Camundongos Knockout , Infarto do Miocárdio , Miocárdio , Remodelação Ventricular , Animais , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Infarto do Miocárdio/genética , Infarto do Miocárdio/fisiopatologia , Miocárdio/metabolismo , Miocárdio/patologia , Matriz Extracelular/metabolismo , Matriz Extracelular/patologia , Camundongos Endogâmicos C57BL , Serpinas/metabolismo , Serpinas/genética , Função Ventricular Esquerda , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Masculino , Proteínas de Fase AgudaRESUMO
AIM: Phenylacetylglutamine (PAGln) is a phenylalanine-derived metabolite produced by gut microbiota with mechanistic links to heart failure (HF)-relevant phenotypes. We sought to investigate the prognostic value of PAGln in patients with stable HF. METHODS AND RESULTS: Fasting plasma PAGln levels were measured by stable-isotope-dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) in patients with stable HF from two large cohorts. All-cause mortality was assessed at 5-year follow-up in the Cleveland cohort, and HF, hospitalization, or mortality were assessed at 3-year follow-up in the Berlin cohort. Within the Cleveland cohort, median PAGln levels were 4.2 (interquartile range [IQR] 2.4-6.9) µM. Highest quartile of PAGln was associated with 3.09-fold increased mortality risk compared to lowest quartile. Following adjustments for traditional risk factors, as well as race, estimated glomerular filtration rate, amino-terminal pro-B-type natriuretic peptide, high-sensitivity C-reactive protein, left ventricular ejection fraction, ischaemic aetiology, and HF drug treatment, elevated PAGln levels remained predictive of 5-year mortality in quartile comparisons (adjusted hazard ratio [HR] [95% confidence interval, CI] for Q4 vs Q1: 1.64 [1.07-2.53]). In the Berlin cohort, a similar distribution of PAGln levels was observed (median 3.2 [IQR 2.0-4.8] µM), and PAGln levels were associated with a 1.92-fold increase in 3-year HF hospitalization or all-cause mortality risk (adjusted HR [95% CI] for Q4 vs Q1: 1.92 [1.02-3.61]). Prognostic value of PAGln appears to be independent of trimethylamine N-oxide levels. CONCLUSION: High levels of PAGln are associated with adverse outcomes independent of traditional cardiac risk factors and cardio-renal risk markers.
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Microbioma Gastrointestinal , Glutamina/análogos & derivados , Insuficiência Cardíaca , Humanos , Prognóstico , Biomarcadores , Volume Sistólico , Cromatografia Líquida , Função Ventricular Esquerda , Espectrometria de Massas em TandemRESUMO
We report a massive field-of-view and high-speed videography platform for measuring the sub-cellular traction forces of more than 10,000 biological cells over 13 mm2 at 83 frames per second. Our Single-Pixel Optical Tracers (SPOT) tool uses 2-dimensional diffraction gratings embedded into a soft substrate to convert cells' mechanical traction force into optical colors detectable by a video camera. The platform measures the sub-cellular traction forces of diverse cell types, including tightly connected tissue sheets and near isolated cells. We used this platform to explore the mechanical wave propagation in a tightly connected sheet of Neonatal Rat Ventricular Myocytes (NRVMs) and discovered that the activation time of some tissue regions are heterogeneous from the overall spiral wave behavior of the cardiac wave.
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Miócitos Cardíacos , Animais , Ratos , Miócitos Cardíacos/citologia , Técnicas Biossensoriais/métodos , Técnicas Biossensoriais/instrumentação , Desenho de Equipamento , Gravação em Vídeo , Células CultivadasRESUMO
Out-of-hospital cardiac arrest is associated with a dismal mortality rate and low long-term survival. A large pharmacological knowledge gap exists in identifying drugs that preserve neurological function and increase long-term survival after cardiac arrest. In this issue of the JCI, Li, Zhu, and colleagues report on their engineering of a 20-amino acid cell-permeable peptide (TAT-PHLPP9c) that antagonized the phosphatase PHLPP1 and prevented PHLPP1-mediated dephosphorylation and AKT inactivation. TAT-PHLPP9c administration maintained activated AKT after arrest and led to AKT-mediated beneficial effects on the heart, brain, and metabolism, resulting in increased cardiac output and cerebral blood flow and rescue of ATP levels in affected tissues. TAT-PHLPP9c improved neurological outcomes and increased survival after cardiac arrest in murine and porcine models of cardiac arrest. These findings provide proof of concept that pharmacological targeting of PHLPP1 may be a promising approach to augmenting long-term survival after cardiac arrest.
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Reanimação Cardiopulmonar , Parada Cardíaca Extra-Hospitalar , Camundongos , Animais , Suínos , Reanimação Cardiopulmonar/métodos , Monoéster Fosfórico Hidrolases , Proteínas Proto-Oncogênicas c-akt , CoraçãoRESUMO
After heart injury, dead heart muscle is replaced by scar tissue. Fibroblasts can electrically couple with myocytes, and changes in fibroblast membrane potential can lead to myocyte excitability, which suggests that fibroblast-myocyte coupling in scar tissue may be responsible for arrhythmogenesis. However, the physiologic relevance of electrical coupling of myocytes and fibroblasts and its impact on cardiac excitability in vivo have never been demonstrated. We genetically engineered a mouse that expresses the optogenetic cationic channel ChR2 (H134R) exclusively in cardiac fibroblasts. After myocardial infarction, optical stimulation of scar tissue elicited organ-wide cardiac excitation and induced arrhythmias in these animals. Complementing computational modeling with experimental approaches, we showed that gap junctional and ephaptic coupling, in a synergistic yet functionally redundant manner, excited myocytes coupled to fibroblasts.
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Arritmias Cardíacas , Channelrhodopsins , Cicatriz , Fibroblastos , Miócitos Cardíacos , Animais , Camundongos , Arritmias Cardíacas/genética , Arritmias Cardíacas/fisiopatologia , Cicatriz/patologia , Cicatriz/fisiopatologia , Fibroblastos/fisiologia , Miócitos Cardíacos/fisiologia , Channelrhodopsins/genética , Channelrhodopsins/fisiologia , Optogenética , Conexina 43/genética , Conexina 43/fisiologia , Técnicas de Inativação de GenesRESUMO
We report a large field-of-view and high-speed videography platform for measuring the sub-cellular traction forces of more than 10,000 biological cells over 13mm 2 at 83 frames per second. Our Single-Pixel Optical Tracers (SPOT) tool uses 2-dimensional diffraction gratings embedded into a soft substrate to convert cells' mechanical traction stress into optical colors detectable by a video camera. The platform measures the sub-cellular traction forces of diverse cell types, including tightly connected tissue sheets and near isolated cells. We used this platform to explore the mechanical wave propagation in a tightly connected sheet of Neonatal Rat Ventricular Myocytes (NRVMs) and discovered that the activation time of some tissue regions are heterogeneous from the overall spiral wave behavior of the cardiac wave. One-Sentence Summary: An optical platform for fast, concurrent measurements of cell mechanics at 83 frames per second, over a large area of 13mm 2 .
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Background: Hantaviruses - dichotomized into New World (i.e. Andes virus, ANDV; Sin Nombre virus, SNV) and Old-World viruses (i.e. Hantaan virus, HTNV) - are zoonotic viruses transmitted from rodents to humans. Currently, no FDA-approved vaccines against hantaviruses exist. Given the recent breakthrough to human-human transmission by the ANDV, an essential step is to establish an effective pandemic preparedness infrastructure to rapidly identify cell tropism, infective potential, and effective therapeutic agents through systematic investigation. Methods: We established human cell model systems in lung (airway and distal lung epithelial cells), heart (pluripotent stem cell-derived (PSC-) cardiomyocytes), and brain (PSC-astrocytes) cell types and subsequently evaluated ANDV, HTNV and SNV tropisms. Transcriptomic, lipidomic and bioinformatic data analyses were performed to identify the molecular pathogenic mechanisms of viruses in different cell types. This cell-based infection system was utilized to establish a drug testing platform and pharmacogenomic comparisons. Results: ANDV showed broad tropism for all cell types assessed. HTNV replication was predominantly observed in heart and brain cells. ANDV efficiently replicated in human and mouse 3D distal lung organoids. Transcriptomic analysis showed that ANDV infection resulted in pronounced inflammatory response and downregulation of cholesterol biosynthesis pathway in lung cells. Lipidomic profiling revealed that ANDV-infected cells showed reduced level of cholesterol esters and triglycerides. Further analysis of pathway-based molecular signatures showed that, compared to SNV and HTNV, ANDV infection caused drastic lung cell injury responses. A selective drug screening identified STING agonists, nucleoside analogues and plant-derived compounds that inhibited ANDV viral infection and rescued cellular metabolism. In line with experimental results, transcriptome data shows that the least number of total and unique differentially expressed genes were identified in urolithin B- and favipiravir-treated cells, confirming the higher efficiency of these two drugs in inhibiting ANDV, resulting in host cell ability to balance gene expression to establish proper cell functioning. Conclusions: Overall, our study describes advanced human PSC-derived model systems and systems-level transcriptomics and lipidomic data to better understand Old and New World hantaviral tropism, as well as drug candidates that can be further assessed for potential rapid deployment in the event of a pandemic.
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The ketogenic diet (KD) has demonstrated benefits in numerous clinical studies and animal models of disease in modulating the immune response and promoting a systemic anti-inflammatory state. Here we investigate the effects of a KD on systemic toxicity in mice following SARS-CoV-2 infection. Our data indicate that under KD, SARS-CoV-2 reduces weight loss with overall improved animal survival. Muted multi-organ transcriptional reprogramming and metabolism rewiring suggest that a KD initiates and mitigates systemic changes induced by the virus. We observed reduced metalloproteases and increased inflammatory homeostatic protein transcription in the heart, with decreased serum pro-inflammatory cytokines (i.e., TNF-α, IL-15, IL-22, G-CSF, M-CSF, MCP-1), metabolic markers of inflammation (i.e., kynurenine/tryptophane ratio), and inflammatory prostaglandins, indicative of reduced systemic inflammation in animals infected under a KD. Taken together, these data suggest that a KD can alter the transcriptional and metabolic response in animals following SARS-CoV-2 infection with improved mice health, reduced inflammation, and restored amino acid, nucleotide, lipid, and energy currency metabolism.