scholarly journals Mutation-specific differences in arrhythmias and drug responses in CPVT patients: simultaneous patch clamp and video imaging of iPSC derived cardiomyocytes

2019 ◽  
Vol 47 (2) ◽  
pp. 1067-1077 ◽  
Author(s):  
R. P. Pölönen ◽  
H. Swan ◽  
K. Aalto-Setälä

AbstractCatecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited cardiac disease characterized by arrhythmias under adrenergic stress. Mutations in the cardiac ryanodine receptor (RYR2) are the leading cause for CPVT. We characterized electrophysiological properties of CPVT patient-specific induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) carrying different mutations in RYR2 and evaluated effects of carvedilol and flecainide on action potential (AP) and contractile properties of hiPSC-CMs. iPSC-CMs were generated from skin biopsies of CPVT patients carrying exon 3 deletion (E3D) and L4115F mutation in RYR2. APs and contractile movement were recorded simultaneously from the same hiPSC-CMs. Differences in AP properties of ventricular like CMs were seen in CPVT and control CMs: APD90 of both E3D (n = 20) and L4115F (n = 25) CPVT CMs was shorter than in control CMs (n = 15). E3D-CPVT CMs had shortest AP duration, lowest AP amplitude, upstroke velocity and more depolarized diastolic potential than controls. Adrenaline had positive and carvedilol and flecainide negative chronotropic effect in all hiPSC CMs. CPVT CMs had increased amount of delayed after depolarizations (DADs) and early after depolarizations (EADs) after adrenaline exposure. E3D CPVT CMs had the most DADs, EADs, and tachyarrhythmia. Discordant negatively coupled alternans was seen in L4115F CPVT CMs. Carvedilol cured almost all arrhythmias in L4115F CPVT CMs. Both drugs decreased contraction amplitude in all hiPSC CMs. E3D CPVT CMs have electrophysiological properties, which render them more prone to arrhythmias. iPSC-CMs provide a unique platform for disease modeling and drug screening for CPVT. Combining electrophysiological measurements, we can gain deeper insight into mechanisms of arrhythmias.

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Henry Joutsijoki ◽  
Markus Haponen ◽  
Jyrki Rasku ◽  
Katriina Aalto-Setälä ◽  
Martti Juhola

The focus of this research is on automated identification of the quality of human induced pluripotent stem cell (iPSC) colony images. iPS cell technology is a contemporary method by which the patient’s cells are reprogrammed back to stem cells and are differentiated to any cell type wanted. iPS cell technology will be used in future to patient specific drug screening, disease modeling, and tissue repairing, for instance. However, there are technical challenges before iPS cell technology can be used in practice and one of them is quality control of growing iPSC colonies which is currently done manually but is unfeasible solution in large-scale cultures. The monitoring problem returns to image analysis and classification problem. In this paper, we tackle this problem using machine learning methods such as multiclass Support Vector Machines and several baseline methods together with Scaled Invariant Feature Transformation based features. We perform over 80 test arrangements and do a thorough parameter value search. The best accuracy (62.4%) for classification was obtained by using ak-NN classifier showing improved accuracy compared to earlier studies.


Author(s):  
Xun Xu ◽  
Yan Nie ◽  
Weiwei Wang ◽  
Imran Ullah ◽  
Wing Tai Tung ◽  
...  

Human induced pluripotent stem cells (hiPSCs) are a promising cell source to generate the patient-specific lung organoid given their superior differentiation potential. However, the current 3D cell culture approach is tedious and time-consuming with a low success rate and high batch-to-batch variability. Here, we explored the establishment of lung bud organoids by systematically adjusting the initial confluence levels and homogeneity of cell distribution. The efficiency of single cell seeding and clump seeding was compared. Instead of the traditional 3D culture, we established a 2.5D organoid culture to enable the direct monitoring of the internal structure via microscopy. It was found that the cell confluence and distribution prior to induction were two key parameters, which strongly affected hiPSC differentiation trajectories. Lung bud organoids with positive expression of NKX 2.1, in a single-cell seeding group with homogeneously distributed hiPSCs at 70%confluence (SC_70%_hom) or a clump seeding group with heterogeneously distributed cells at 90%confluence (CL_90%_het), can be observed as early as 9 days post induction. These results suggest that a successful lung bud organoid formation with single-cell seeding of hiPSCs requires a moderate confluence and homogeneous distribution of cells, while high confluence would be a prominent factor to promote the lung organoid formation when seeding hiPSCs as clumps. 2.5D organoids generated with defined culture conditions could become a simple, efficient, and valuable tool facilitating drug screening, disease modeling and personalized medicine.


2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Cynthia St. Hilaire ◽  
Hui Jin ◽  
Yuting Huang ◽  
Dan Yang ◽  
Alejandra Negro ◽  
...  

Objective: The objective of this study was to develop a patient-specific induced pluripotent stem cell (iPSC)-based disease model to understand the process by which CD73-deficiency leads to vascular calcification in the disease, Arterial Calcification due to Deficiency of CD73 (ACDC). Approach & Results: ACDC is an autosomal recessive disease resulting from mutations in the gene encoding for CD73, which converts extracellular AMP to adenosine. CD73-deficiency manifests with tortuosity and vascular calcification of the medial layer of lower-extremity arteries, a pathology associated with diabetes and chronic kidney disease. We previously identified that dermal fibroblasts isolated from ACDC patients calcify in vitro, however in vivo studies of the vasculature are limited, as murine models of CD73 deficiency do not recapitulate the human disease phenotype. Thus, we created iPSCs from ACDC patients and control fibroblasts. ACDC and Control iPSCs form teratomas when injected in immune-compromised mice, however ACDC iPSC teratomas exhibit extensive calcifications. Control and ACDC iPSCs were differentiated down the mesenchymal lineage (MSC) and while there was no difference in chondrogenesis and adipogenesis, ACDC iMSCs underwent osteogenesis sooner than control iPSC, have higher activity of tissue-nonspecific alkaline phosphatase (TNAP), and lower levels of extracellular adenosine. During osteogenic simulation, TNAP activity in ACDC cells significantly increased adenosine levels, however, not to levels needed for functional compensatory stimulation of the adenosine receptors. Inhibition of TNAP with levimisole ablates this increase in adenosine. Treatment with an A2b adenosine receptor (AR) agonist drastically reduced TNAP activity in vitro, and calcification in ACDC teratomas, as did treatment with etidronate, which is currently being tested in a clinical trial on ACDC patients. Conclusions: These results illustrate a pro-osteogenic phenotype in CD73-deficient cells whereby TNAP activity attempts to compensate for CD73 deficiency, but subsequently induces calcification that can be reversed by activation of the A2bAR. The iPSC teratoma model may be used to screen other potential therapeutics for calcification disorders.


2020 ◽  
Vol 21 (19) ◽  
pp. 6997 ◽  
Author(s):  
Davide Rovina ◽  
Elisa Castiglioni ◽  
Francesco Niro ◽  
Sara Mallia ◽  
Giulio Pompilio ◽  
...  

The ultimate goal of precision disease modeling is to artificially recreate the disease of affected people in a highly controllable and adaptable external environment. This field has rapidly advanced which is evident from the application of patient-specific pluripotent stem-cell-derived precision therapies in numerous clinical trials aimed at a diverse set of diseases such as macular degeneration, heart disease, spinal cord injury, graft-versus-host disease, and muscular dystrophy. Despite the existence of semi-adequate treatments for tempering skeletal muscle degeneration in dystrophic patients, nonischemic cardiomyopathy remains one of the primary causes of death. Therefore, cardiovascular cells derived from muscular dystrophy patients’ induced pluripotent stem cells are well suited to mimic dystrophin-associated cardiomyopathy and hold great promise for the development of future fully effective therapies. The purpose of this article is to convey the realities of employing precision disease models of dystrophin-associated cardiomyopathy. This is achieved by discussing, as suggested in the title echoing William Shakespeare’s words, the settlements (or “leagues”) made by researchers to manage the constraints (“betwixt mine eye and heart”) distancing them from achieving a perfect precision disease model.


2020 ◽  
Author(s):  
◽  
Loren Ornelas ◽  
Emilda Gomez ◽  
Lindsay Panther ◽  
Aaron Frank ◽  
...  

SummaryNeurodegenerative diseases present a challenge for systems biology, due to the lack of reliable animal models and the difficulties in obtaining samples from patients at early stages of disease, when interventions might be most effective. Studying induced pluripotent stem cell (iPSC)-derived neurons could overcome these challenges and dramatically accelerate and broaden therapeutic strategies. Here we undertook a network-based multi-omic characterization of iPSC-derived motor neurons from ALS patients carrying genetically dominant hexanucleotide expansions in C9orf72 to gain a deeper understanding of the relationship between DNA, RNA, epigenetics and protein in the same pool of tissue. ALS motor neurons showed the expected C9orf72-related alterations to specific nucleoporins and production of dipeptide repeats. RNA-seq, ATAC-seq and data-independent acquisition mass-spectrometry (DIA-MS) proteomics were then performed on the same motor neuron cultures. Using integrative computational methods that combined all of the omics, we discovered a number of novel dysregulated pathways including biological adhesion and extracellular matrix organization and disruption in other expected pathways such as RNA splicing and nuclear transport. We tested the relevance of these pathways in vivo in a C9orf72 Drosophila model, analyzing the data to determine which pathways were causing disease phenotypes and which were compensatory. We also confirmed that some pathways are altered in late-stage neurodegeneration by analyzing human postmortem C9 cervical spine data. To validate that these key pathways were integral to the C9 signature, we prepared a separate set of C9orf72 and control motor neuron cultures using a different differentiation protocol and applied the same methods. As expected, there were major overall differences between the differentiation protocols, especially at the level of in individual omics data. However, a number of the core dysregulated pathways remained significant using the integrated multiomic analysis. This new method of analyzing patient specific neural cultures allows the generation of disease-related hypotheses with a small number of patient lines which can be tested in larger cohorts of patients.


Biology ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 981
Author(s):  
Takeshi Tokuyama ◽  
Razan Elfadil Ahmed ◽  
Nawin Chanthra ◽  
Tatsuya Anzai ◽  
Hideki Uosaki

Mitochondrial cardiomyopathy (MCM) is characterized as an oxidative phosphorylation disorder of the heart. More than 100 genetic variants in nuclear or mitochondrial DNA have been associated with MCM. However, the underlying molecular mechanisms linking genetic variants to MCM are not fully understood due to the lack of appropriate cellular and animal models. Patient-specific induced pluripotent stem cell (iPSC)-derived cardiomyocytes (iPSC-CMs) provide an attractive experimental platform for modeling cardiovascular diseases and predicting drug efficacy to such diseases. Here we introduce the pathological and therapeutic studies of MCM using iPSC-CMs and discuss the questions and latest strategies for research using iPSC-CMs.


2021 ◽  
Vol 22 (15) ◽  
pp. 8132
Author(s):  
Jennifer Zhang ◽  
Oscar Hou-In Chou ◽  
Yiu-Lam Tse ◽  
Kwong-Man Ng ◽  
Hung-Fat Tse

Inherited cardiomyopathies are among the major causes of heart failure and associated with significant mortality and morbidity. Currently, over 70 genes have been linked to the etiology of various forms of cardiomyopathy, some of which are X-linked. Due to the lack of appropriate cell and animal models, it has been difficult to model these X-linked cardiomyopathies. With the advancement of induced pluripotent stem cell (iPSC) technology, the ability to generate iPSC lines from patients with X-linked cardiomyopathy has facilitated in vitro modelling and drug testing for the condition. Nonetheless, due to the mosaicism of the X-chromosome inactivation, disease phenotypes of X-linked cardiomyopathy in heterozygous females are also usually more heterogeneous, with a broad spectrum of presentation. Recent advancements in iPSC procedures have enabled the isolation of cells with different lyonisation to generate isogenic disease and control cell lines. In this review, we will summarise the current strategies and examples of using an iPSC-based model to study different types of X-linked cardiomyopathy. The potential application of isogenic iPSC lines derived from a female patient with heterozygous Danon disease and drug screening will be demonstrated by our preliminary data. The limitations of an iPSC-derived cardiomyocyte-based platform will also be addressed.


2020 ◽  
Vol 7 (4) ◽  
pp. 133
Author(s):  
Xiufang Guo ◽  
Agnes Badu-Mensah ◽  
Michael C. Thomas ◽  
Christopher W. McAleer ◽  
James J. Hickman

In vitro generation of functional neuromuscular junctions (NMJs) utilizing the same induced pluripotent stem cell (iPSC) source for muscle and motoneurons would be of great value for disease modeling and tissue engineering. Although, differentiation and characterization of iPSC-derived motoneurons are well established, and iPSC-derived skeletal muscle (iPSC-SKM) has been reported, there is a general lack of systemic and functional characterization of the iPSC-SKM. This study performed a systematic characterization of iPSC-SKM differentiated using a serum-free, small molecule-directed protocol. Morphologically, the iPSC-SKM demonstrated the expression and appropriate distribution of acetylcholine, ryanodine and dihydropyridine receptors. Fiber type analysis revealed a mixture of human fast (Type IIX, IIA) and slow (Type I) muscle types and the absence of animal Type IIB fibers. Functionally, the iPSC-SKMs contracted synchronously upon electrical stimulation, with the contraction force comparable to myofibers derived from primary myoblasts. Most importantly, when co-cultured with human iPSC-derived motoneurons from the same iPSC source, the myofibers contracted in response to motoneuron stimulation indicating the formation of functional NMJs. By demonstrating comparable structural and functional capacity to primary myoblast-derived myofibers, this defined, iPSC-SKM system, as well as the personal NMJ system, has applications for patient-specific drug testing and investigation of muscle physiology and disease.


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Marcela K Preininger ◽  
Rajneesh Jha ◽  
Qingling Wu ◽  
Monalisa Singh ◽  
Joshua T Maxwell ◽  
...  

Introduction: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome characterized by diastolic store overload-induced Ca2+ waves during β-adrenergic receptor (β-AR) stimulation. Mysteriously, β-blockers are ineffective at abolishing stress-induced ventricular arrhythmias in ~25% of patients. Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) generated from these CPVT patients offer an attractive system for investigating the phenomenon, but it remains unknown whether iPSC-CMs can recapitulate clinically observed patient-specific drug responses. Hypothesis: This study assessed the hypothesis that patient-specific refractoriness to β-blocker therapy can be observed in vitro using CPVT iPSC-CMs. Methods: We generated iPSC-CMs from a control individual and a CPVT patient insensitive to the widely prescribed β-blocker nadolol, but responsive to flecainide, and compared the efficacy of the two drugs in vitro in diminishing diastolic Ca2+ waves and restoring Ca2+ spark parameters during β-AR stimulation. Results: In CPVT hiPSC-CMs (n = 34), β-AR agonism elicited intense diastolic Ca2+ waves and potentiated unduly frequent, large, and prolonged Ca2+ sparks compared to control iPSC-CMs (n = 12). Pursuant to the patient’s in vivo responses, nadolol-treated CPVT iPSC-CMs (n = 27) demonstrated inadequate improvement of Ca2+ handling defects during β-AR stimulation relative to flecainide-treated CPVT iPSC-CMs (n = 25). Nadolol showed no significant effect on the frequency of diastolic Ca2+ waves, but reduced mean amplitude by 50% (p < 0.0001). In contrast, flecainide reduced both frequency and amplitude by 83% (p < 0.001) and 72% (p < 0.0001), respectively. During nadolol treatment, Ca2+ spark frequency, width, and duration remained significantly altered, while flecainide restored all Ca2+ spark parameters to baseline levels. Conclusions: Clinically observed recalcitrance to β-blocker therapy in individuals with CPVT can be modeled in vitro using patient-derived iPSC-CMs. Furthermore, the efficacy of other drugs such as flecainide can be comparatively evaluated, supporting the use of patient-specific iPSC-CMs as a clinically-relevant implement of precision medicine.


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