Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 112
Filtrar
1.
Stem Cell Res ; 48: 101944, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33038615

RESUMO

CRISPR/Cas9 technology is a powerful tool, owing to its robust on-target activity and high fidelity. Mutated Cas9 without nuclease activity (dCas9) fused to transcriptional modulators, can function as transcriptional inhibitors or activators (CRISPRa). We generated homozygous human induced pluripotent stem cell (hiPSC) lines with an inserted CRISPRa cassette into the AAVS1 locus whilst maintaining pluripotency and genomic integrity, the ability to differentiate into all three germ layers, generate functional cardiomyocytes, and validated Cas9-mediated induction of endogenous gene expression. Our generated hiPSC-CRISPRa offers a valuable tool for studying endogenous transcriptional modulation with single and multiplexed possibilities in all human cell types.

2.
Cardiovasc Res ; 2020 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-32777030

RESUMO

AIMS: Arrhythmias and sudden cardiac death (SCD) occur commonly in patients with heart failure. We found T-box 5 (TBX5) dysregulated in ventricular myocardium from heart failure patients and thus we hypothesized that TBX5 reduction contributes to arrhythmia development in these patients. To understand the underlying mechanisms, we aimed to reveal the ventricular TBX5-dependent transcriptional network and further test the therapeutic potential of TBX5 level normalization in mice with documented arrhythmias. METHODS AND RESULTS: We used a mouse model of TBX5 conditional deletion in ventricular cardiomyocytes. Ventricular (v) TBX5 loss in mice resulted in mild cardiac dysfunction and arrhythmias and was associated with a high mortality rate (60%) due to SCD. Upon angiotensin stimulation, vTbx5KO mice showed exacerbated cardiac remodelling and dysfunction suggesting a cardioprotective role of TBX5. RNA sequencing of a ventricular specific TBX5KO mouse and TBX5 chromatin immunoprecipitation were used to dissect TBX5 transcriptional network in cardiac ventricular tissue. Overall, we identified 47 transcripts expressed under the control of TBX5, which may have contributed to the fatal arrhythmias in vTbx5KO mice. These included transcripts encoding for proteins implicated in cardiac conduction and contraction (Gja1, Kcnj5, Kcng2, Cacna1g, Chrm2), in cytoskeleton organization (Fstl4, Pdlim4, Emilin2, Cmya5), and cardiac protection upon stress (Fhl2, Gpr22, Fgf16). Interestingly, after TBX5 loss and arrhythmia development in vTbx5KO mice, TBX5 protein level normalization by systemic adeno-associated-virus (AAV) 9 application, re-established TBX5-dependent transcriptome. Consequently, cardiac dysfunction was ameliorated and the propensity of arrhythmia occurrence was reduced. CONCLUSIONS: This study uncovers a novel cardioprotective role of TBX5 in the adult heart and provides preclinical evidence for the therapeutic value of TBX5 protein normalization in the control of arrhythmia. TRANSLATIONAL PERSPECTIVE: Cardiovascular disease (CVD) is the number one cause of death worldwide (WHO factsheets 09/2016). Although more than 60% of CVD-related deaths are due to out-of-hospital sudden cardiac death (SCD), we have little insight in the mechanisms underlying SCD pathophysiology. Our data show a link between TBX5 dysregulation and arrhythmia occurrence in patients. To test the therapeutic potential of TBX5, we normalized TBX5 levels in a mouse model with TBX5 dysregulation, which developed arrhythmias and SCD. TBX5 normalization re-established TBX5 target gene expression and more importantly, rescued the arrhythmia phenotype. Altogether, we provide proof-of-concept for the therapeutic potential of TBX5 expression restoration against arrhythmia and SCD.

3.
Nat Commun ; 11(1): 3791, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32728089

RESUMO

Brain organoids are promising tools for disease modeling and drug development. For proper neuronal network formation excitatory and inhibitory neurons as well as glia need to co-develop. Here, we report the directed self-organization of human induced pluripotent stem cells in a collagen hydrogel towards a highly interconnected neuronal network at a macroscale tissue format. Bioengineered Neuronal Organoids (BENOs) comprise interconnected excitatory and inhibitory neurons with supportive astrocytes and oligodendrocytes. Giant depolarizing potential (GDP)-like events observed in early BENO cultures mimic early network activity of the fetal brain. The observed GABA polarity switch and reduced GDPs in >40 day BENO indicate progressive neuronal network maturation. BENOs demonstrate expedited complex network burst development after two months and evidence for long-term potentiation. The similarity of structural and functional properties to the fetal brain may allow for the application of BENOs in studies of neuronal plasticity and modeling of disease.


Assuntos
Encéfalo/citologia , Neurogênese , Plasticidade Neuronal/fisiologia , Organoides/fisiologia , Engenharia Tecidual/métodos , Potenciais de Ação/fisiologia , Encéfalo/crescimento & desenvolvimento , Técnicas de Cultura de Células , Diferenciação Celular , Humanos , Células-Tronco Pluripotentes Induzidas/fisiologia , Neurônios/fisiologia , Ácido gama-Aminobutírico/metabolismo
4.
Circulation ; 142(11): 1059-1076, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32623905

RESUMO

BACKGROUND: Noonan syndrome (NS) is a multisystemic developmental disorder characterized by common, clinically variable symptoms, such as typical facial dysmorphisms, short stature, developmental delay, intellectual disability as well as cardiac hypertrophy. The underlying mechanism is a gain-of-function of the RAS-mitogen-activated protein kinase signaling pathway. However, our understanding of the pathophysiological alterations and mechanisms, especially of the associated cardiomyopathy, remains limited and effective therapeutic options are lacking. METHODS: Here, we present a family with two siblings displaying an autosomal recessive form of NS with massive hypertrophic cardiomyopathy as clinically the most prevalent symptom caused by biallelic mutations within the leucine zipper-like transcription regulator 1 (LZTR1). We generated induced pluripotent stem cell-derived cardiomyocytes of the affected siblings and investigated the patient-specific cardiomyocytes on the molecular and functional level. RESULTS: Patients' induced pluripotent stem cell-derived cardiomyocytes recapitulated the hypertrophic phenotype and uncovered a so-far-not-described causal link between LZTR1 dysfunction, RAS-mitogen-activated protein kinase signaling hyperactivity, hypertrophic gene response and cellular hypertrophy. Calcium channel blockade and MEK inhibition could prevent some of the disease characteristics, providing a molecular underpinning for the clinical use of these drugs in patients with NS, but might not be a sustainable therapeutic option. In a proof-of-concept approach, we explored a clinically translatable intronic CRISPR (clustered regularly interspaced short palindromic repeats) repair and demonstrated a rescue of the hypertrophic phenotype. CONCLUSIONS: Our study revealed the human cardiac pathogenesis in patient-specific induced pluripotent stem cell-derived cardiomyocytes from NS patients carrying biallelic variants in LZTR1 and identified a unique disease-specific proteome signature. In addition, we identified the intronic CRISPR repair as a personalized and in our view clinically translatable therapeutic strategy to treat NS-associated hypertrophic cardiomyopathy.

5.
Cells ; 9(6)2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32485910

RESUMO

Non-human primates (NHP) are important surrogate models for late preclinical development of advanced therapy medicinal products (ATMPs), including induced pluripotent stem cell (iPSC)-based therapies, which are also under development for heart failure repair. For effective heart repair by remuscularization, large numbers of cardiomyocytes are required, which can be obtained by efficient differentiation of iPSCs. However, NHP-iPSC generation and long-term culture in an undifferentiated state under feeder cell-free conditions turned out to be problematic. Here we describe the reproducible development of rhesus macaque (Macaca mulatta) iPSC lines. Postnatal rhesus skin fibroblasts were reprogrammed under chemically defined conditions using non-integrating vectors. The robustness of the protocol was confirmed using another NHP species, the olive baboon (Papio anubis). Feeder-free maintenance of NHP-iPSCs was essentially dependent on concurrent Wnt-activation by GSK-inhibition (Gi) and Wnt-inhibition (Wi). Generated NHP-iPSCs were successfully differentiated into cardiomyocytes using a combined growth factor/GiWi protocol. The capacity of the iPSC-derived cardiomyocytes to self-organize into contractile engineered heart muscle (EHM) was demonstrated. Collectively, this study establishes a reproducible protocol for the robust generation and culture of NHP-iPSCs, which are useful for preclinical testing of strategies for cell replacement therapies in NHP.

9.
Expert Opin Drug Saf ; 19(5): 553-558, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32163309

RESUMO

This report summarizes and discusses talks delivered at an educational course offered during the 2019 Annual Meeting of the Safety Pharmacology Society on advanced therapy medicinal products (ATMPs) and cell gene therapeutic products (CGTPs). ATMPs and CGTPs comprise gene and cell therapy medicinal products, tissue-engineered products, or the incorporation of one of these products into a medical device. Cited examples of ATMPs are autologous CD34+ cells encoding for the ßA-T87Q-globin gene, CAR (chimeric antigen receptor)-T cell immunotherapy medicines, genome editing products, and engineered heart muscle patches constructed from induced human pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) for remuscularization of the failing human heart. The nonclinical assessment of efficacy and safety of ATMPs for undertaking human clinical trials requires innovative, product-specific strategies. In order to succeed in gaining marketing approval for these novel medicines, sponsors should establish well-defined collaborative relationships with the appropriate regulatory authorities.

10.
Sci Rep ; 10(1): 209, 2020 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-31937807

RESUMO

The sarcomeric troponin-tropomyosin complex is a critical mediator of excitation-contraction coupling, sarcomeric stability and force generation. We previously reported that induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) from patients with a dilated cardiomyopathy (DCM) mutation, troponin T (TnT)-R173W, display sarcomere protein misalignment and impaired contractility. Yet it is not known how TnT mutation causes dysfunction of sarcomere microdomains and how these events contribute to misalignment of sarcomeric proteins in presence of DCM TnT-R173W. Using a human iPSC-CM model combined with CRISPR/Cas9-engineered isogenic controls, we uncovered that TnT-R173W destabilizes molecular interactions of troponin with tropomyosin, and limits binding of PKA to local sarcomere microdomains. This attenuates troponin phosphorylation and dysregulates local sarcomeric microdomains in DCM iPSC-CMs. Disrupted microdomain signaling impairs MYH7-mediated, AMPK-dependent sarcomere-cytoskeleton filament interactions and plasma membrane attachment. Small molecule-based activation of AMPK can restore TnT microdomain interactions, and partially recovers sarcomere protein misalignment as well as impaired contractility in DCM TnT-R173W iPSC-CMs. Our findings suggest a novel therapeutic direction targeting sarcomere- cytoskeleton interactions to induce sarcomere re-organization and contractile recovery in DCM.

11.
Front Cell Dev Biol ; 7: 261, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31737628

RESUMO

Background: Among rare channelopathies BrS patients are at high risk of sudden cardiac death (SCD). SCN5A mutations are found in a quarter of patients. Other rare gene mutations including SCN1B have been implicated to BrS. Studying the human cellular phenotype of BrS associated with rare gene mutation remains lacking. Objectives: We sought to study the cellular phenotype of BrS with the SCN1B gene variants using human-induced pluripotent stem cell (hiPSCs)-derived cardiomyocytes (hiPSC-CMs). Methods and Results: A BrS patient suffering from recurrent syncope harboring a two variants (c.629T > C and c.637C > A) in SCN1B, which encodes the function-modifying sodium channel beta1 subunit, and three independent healthy subjects were recruited and their skin biopsies were used to generate hiPSCs, which were differentiated into cardiomyocytes (hiPSC-CMs) for studying the cellular electrophysiology. A significantly reduced peak and late sodium channel current (INa) and a shift of activation curve to more positive potential as well as a shift of inactivation curve to more negative potential were detected in hiPSC-CMs of the BrS patient, indicating that the SCN1B variants impact the function of sodium channels in cardiomyocytes. The reduced INa led to a reduction of amplitude (APA) and upstroke velocity (V max ) of action potentials. Ajmaline, a sodium channel blocker, showed a stronger effect on APA and Vmax in BrS cells as compared to cells from healthy donors. Furthermore, carbachol was able to increase arrhythmia events and the beating frequency in BrS. Conclusion: Our hiPSC-CMs from a BrS-patient with two variants in SCN1B recapitulated some key phenotypic features of BrS and can provide a platform for studies on BrS with SCN1B variants.

12.
J Am Coll Cardiol ; 74(14): 1804-1819, 2019 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-31582141

RESUMO

BACKGROUND: The combination of cardiomyocyte (CM) and vascular cell (VC) fetal reprogramming upon stress culminates in end-stage heart failure (HF) by mechanisms that are not fully understood. Previous studies suggest KLF15 as a key regulator of CM hypertrophy. OBJECTIVES: This study aimed to characterize the impact of KLF15-dependent cardiac transcriptional networks leading to HF progression, amenable to therapeutic intervention in the adult heart. METHODS: Transcriptomic bioinformatics, phenotyping of Klf15 knockout mice, Wnt-signaling-modulated hearts, and pressure overload and myocardial ischemia models were applied. Human KLF15 knockout embryonic stem cells and engineered human myocardium, and human samples were used to validate the relevance of the identified mechanisms. RESULTS: The authors identified a sequential, postnatal transcriptional repression mediated by KLF15 of pathways implicated in pathological tissue remodeling, including distinct Wnt-pathways that control CM fetal reprogramming and VC remodeling. The authors further uncovered a vascular program induced by a cellular crosstalk initiated by CM, characterized by a reduction of KLF15 and a concomitant activation of Wnt-dependent transcriptional signaling. Within this program, a so-far uncharacterized cardiac player, SHISA3, primarily expressed in VCs in fetal hearts and pathological remodeling was identified. Importantly, the KLF15 and Wnt codependent SHISA3 regulation was demonstrated to be conserved in mouse and human models. CONCLUSIONS: The authors unraveled a network interplay defined by KLF15-Wnt dynamics controlling CM and VC homeostasis in the postnatal heart and demonstrated its potential as a cardiac-specific therapeutic target in HF. Within this network, they identified SHISA3 as a novel, evolutionarily conserved VC marker involved in pathological remodeling in HF.

13.
Circ Genom Precis Med ; 12(8): e002491, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31430208

RESUMO

BACKGROUND: Familial atrial septal defect (ASD) has previously been attributed primarily to mutations in cardiac transcription factors. Here, we report a large, multi-generational family (78 members) with ASD combined with a late-onset dilated cardiomyopathy and further characterize the consequences of mutant α-actin. METHODS: We combined a genome-wide linkage analysis with cell biology, microscopy, and molecular biology tools to characterize a novel ACTC1 (cardiac α-actin) mutation identified in association with ASD and late-onset dilated cardiomyopathy in a large, multi-generational family. RESULTS: Using a genome-wide linkage analysis, the ASD disease locus was mapped to chromosome 15q14 harboring the ACTC1 gene. In 15 affected family members, a heterozygous, nonsynonymous, and fully penetrant mutation (p. Gly247Asp) was identified in exon 5 of ACTC1 that was absent in all healthy family members (n=63). In silico tools predicted deleterious consequences of this variant that was found absent in control databases. Ultrastructural analysis of myocardial tissue of one of the mutation carriers showed sarcomeric disarray, myofibrillar degeneration, and increased apoptosis, while cardiac proteomics revealed a significant increase in extracellular matrix proteins. Consistently, structural defects and increased apoptosis were also observed in neonatal rat ventricular cardiomyocytes overexpressing the mutant, but not native human ACTC1. Molecular dynamics studies and additional mechanistic analyses in cardiomyocytes confirmed actin polymerization/turnover defects, thereby affecting contractility. CONCLUSIONS: A combined phenotype of ASD and late-onset heart failure was caused by a heterozygous, nonsynonymous ACTC1 mutation. Mechanistically, we found a shared molecular mechanism of defective actin signaling and polymerization in both cardiac development and contractile function. Detection of ACTC1 mutations in patients with ASD may thus have further clinical implications with regard to monitoring for (late-onset) dilated cardiomyopathy.

14.
Stud Health Technol Inform ; 264: 363-367, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31437946

RESUMO

Methods for cardiac tissue engineering and application in experiments are core technologies developed at the Institute of Pharmacology and Toxicology in Göttingen. As is the case in many academic research laboratories data capture and documentation may be improved to latest methods of digital research. A comprehensive information system infrastructure is the foundation of further advances toward automation of lab processes. A data management system concept is proposed and prototypically deployed that enables traceability of assets within the lab and reproducibility of published assays and results. The prototype integrates existing electronic lab notebook, experiment result database, and a newly introduced research data management system by means of a custom developed portal and integration component. The architecture concept and developed integration tools explore connection of routine experimental work in a biomedical research lab to a universal infrastructure of data.


Assuntos
Pesquisa Biomédica , Engenharia Tecidual , Gestão do Conhecimento , Laboratórios , Reprodutibilidade dos Testes
15.
J Mol Cell Cardiol ; 134: 13-28, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31233754

RESUMO

Cardiac fibrosis is a hallmark of heart failure for which there is no effective pharmacological therapy. By genetic modification and in vivo inhibitor approaches it was suggested that the Rho-associated kinases (ROCK1 and ROCK2) are involved in pro-fibrotic signalling in cardiac fibroblasts and that they may serve as targets for anti-fibrotic therapies. We demonstrate that simultaneous inhibition of ROCK1 and ROCK2 strongly interfered with tissue formation and their biomechanical properties in a model of engineered connective tissue (ECT), comprised of cardiac fibroblasts and collagen. These effects were observed with both rat and human ECT. Inhibitors of different chemistries, including the isoquinoline inhibitors Fasudil and H1152P as well as the pyrazol-phenyl inhibitor SR-3677, showed comparable effects. By combined treatment of ECT with TGF-ß and H1152P, we could identify ROCK as a mediator of TGF-ß-dependent tissue stiffening. Moreover, expression analyses suggested that lysyl oxidase (LOX) is a downstream target of the ROCK-actin-MRTF/SRF pathway and inhibition of this pathway by Latrunculin A and CCG-203971 showed similar anti-fibrotic effects in the ECT model as ROCK inhibitors. In line with the collagen crosslinking function of LOX, its inhibition by ß-aminopropionitrile resulted in reduced ECT stiffness, but let tissue compaction unaffected. Finally, we show that ROCK inhibition also reduced the compaction and stiffness of engineered heart muscle tissues. Our results indicate that pharmacological inhibition of ROCK has a strong anti-fibrotic potential which is in part due to a decrease in the expression of the collagen crosslinking enzyme lysyl oxidase.

16.
Europace ; 21(9): 1410-1421, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31106349

RESUMO

AIMS: Brugada syndrome (BrS) is associated with a pronounced risk to develop sudden cardiac death (SCD). Up to 21% of patients are related to mutations in SCN5A. Studies identified SCN10A as a contributor of BrS. However, the investigation of the human cellular phenotype of BrS in the presence of SCN10A mutations remains lacking. The objective of this study was to establish a cellular model of BrS in presence of SCN10A mutations using human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). METHODS AND RESULTS: Dermal fibroblasts obtained from a BrS patient suffering from SCD harbouring the SCN10A double variants (c.3803G>A and c.3749G>A) and three independent healthy control subjects were reprogrammed to hiPSCs. Human-induced pluripotent stem cells were differentiated into cardiomyocytes (hiPSC-CMs).The hiPSC-CMs from the BrS patient showed a significantly reduced peak sodium channel current (INa) and a significantly reduced ATX II (sea anemone toxin, an enhancer of late INa) sensitive as well as A-887826 (a blocker of SCN10A channel) sensitive late sodium channel current (INa) when compared with the healthy control hiPSC-CMs, indicating loss-of-function of sodium channels. Consistent with reduced INa the action potential amplitude and upstroke velocity (Vmax) were significantly reduced, which may contribute to arrhythmogenesis of BrS. Moreover, Ajmaline effects on action potentials were stronger in BrS-hiPSC-CMs than in healthy control cells. This is in agreement with the higher susceptibility of patients to sodium channel blocking drugs in unmasking BrS. CONCLUSION: Patient-specific hiPSC-CMs are able to recapitulate single-cell phenotype features of BrS with SCN10A mutations and may provide novel opportunities to further elucidate the cellular disease mechanism.

18.
Clin Pharmacol Ther ; 106(3): 642-651, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-30947366

RESUMO

Short QT syndrome (SQTS) predisposes afflicted patients to sudden cardiac death. Until now, only one drug-quinidine-has been shown to be effective in patients with SQTS type 1(SQTS1). The objective of this study was to use human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from a patient with SQTS1 to search for potentially effective drugs for the treatment of SQTS1 patients. Patch clamp and single-cell contraction measurements were employed to assess drug effects. Ivabradine, mexiletine, and ajmaline but not flecainide, ranolazine, or amiodarone prolonged the action potential duration (APD) in hiPSC-CMs from an SQTS1 patient. Ivabradine, ajmaline, and mexiletine inhibited KCNH2 channel currents significantly, which may underlie their APD-prolonging effects. Under proarrhythmic epinephrine stimulation in spontaneously beating SQTS1 hiPSC-CMs, ivabradine, mexiletine, and ajmaline but not flecainide reduced the epinephrine-induced arrhythmic events. The results demonstrate that ivabradine, ajmaline, and mexiletine may be candidate drugs for preventing tachyarrhythmias in SQTS1 patients.


Assuntos
Fármacos Cardiovasculares/farmacologia , Canal de Potássio ERG1/metabolismo , Sistema de Condução Cardíaco/anormalidades , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Potenciais de Ação/efeitos dos fármacos , Arritmias Cardíacas , Relação Dose-Resposta a Droga , Epinefrina/farmacologia , Sistema de Condução Cardíaco/efeitos dos fármacos , Cardiopatias Congênitas , Humanos
19.
Sci Rep ; 9(1): 5651, 2019 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-30948775

RESUMO

Acute myocardial infarction (MI) evokes a systemic inflammatory response and locally the degradation of the necrotic tissue, followed by scar formation. The mechanisms for containment of the infarct zone are not studied well. The study aimed to examine the response of healthy cardiomyocytes to serum of patients with myocardial infarction. Human iPSC-cardiomyocytes (iPSC-CM) generated from two healthy donors were incubated with serum of patients with MI with and without ventricular fibrillation (VF) or of healthy controls. Different cell adhesion molecules were studied by flow cytometry and immunostaining. Cellular electrophysiology was studied by patch clamp. The cell adhesion molecules CD54/ICAM-1, CD58/LFA-3 and CD321/JAM-A were expressed on iPSC-CM within the plasma membrane. Incubation with serum of MI patients reduced the levels of expression of CD54/ICAM-1 and CD321/JAM-A by 15-20%. VF serum was less effective than serum of MI patients without VF. MI serum or VF serum did not affect resting potential, action potential duration or maximum depolarization velocity. Myocardial infarction serum exerts anti-inflammatory effects on healthy cardiomyocytes without affecting their electrical activity, thus helping to contain the infarct zone and to protect healthy tissue. Ventricular fibrillation during MI drives healthy cardiomyocytes towards a pro-inflammatory phenotype.

20.
Front Physiol ; 10: 272, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31024328

RESUMO

Redox signaling affects all aspects of cardiac function and homeostasis. With the development of genetically encoded fluorescent redox sensors, novel tools for the optogenetic investigation of redox signaling have emerged. Here, we sought to develop a human heart muscle model for in-tissue imaging of redox alterations. For this, we made use of (1) the genetically-encoded Grx1-roGFP2 sensor, which reports changes in cellular glutathione redox status (GSH/GSSG), (2) human embryonic stem cells (HES2), and (3) the engineered heart muscle (EHM) technology. We first generated HES2 lines expressing Grx1-roGFP2 in cytosol or mitochondria compartments by TALEN-guided genomic integration. Grx1-roGFP2 sensor localization and function was verified by fluorescence imaging. Grx1-roGFP2 HES2 were then subjected to directed differentiation to obtain high purity cardiomyocyte populations. Despite being able to report glutathione redox potential from cytosol and mitochondria, we observed dysfunctional sarcomerogenesis in Grx1-roGFP2 expressing cardiomyocytes. Conversely, lentiviral transduction of Grx1-roGFP2 in already differentiated HES2-cardiomyocytes and human foreskin fibroblast was possible, without compromising cell function as determined in EHM from defined Grx1-roGFP2-expressing cardiomyocyte and fibroblast populations. Finally, cell-type specific GSH/GSSG imaging was demonstrated in EHM. Collectively, our observations suggests a crucial role for redox signaling in cardiomyocyte differentiation and provide a solution as to how this apparent limitation can be overcome to enable cell-type specific GSH/GSSG imaging in a human heart muscle context.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA