scholarly journals Myofibrillar Structural Variability Underlies Contractile Function in Stem Cell-Derived Cardiomyocytes

2020 ◽  
Author(s):  
Kathryn Ufford ◽  
Sabrina Friedline ◽  
Zhaowen Tong ◽  
Vi T. Tang ◽  
Amani S. Dobbs ◽  
...  

SummaryDisease modeling and pharmaceutical testing using cardiomyocytes derived from induced pluripotent stem cell (iPSC-CMs) requires accurate assessment of contractile function. Micropatterning iPSC-CMs on elastic substrates controls cell shape and alignment to enable contractile studies, but the determinants of intrinsic variability in this system have been incompletely characterized. The primary objective of this study was to determine the impact of myofibrillar structure on contractile function in iPSC-CMs. After labeling micropatterned iPSC-CMs with a cell permeant F-actin dye, we imaged both myofibrillar structure and contractile function. Using automated myofibrillar image analysis, we demonstrate that myofibrillar abundance is widely variable among individual iPSC-CMs and strongly correlates with contractile function. This variability is not reduced by subcloning from single iPSCs to reduce genetic heterogeneity, persists with two different iPSC-CM purification methods, and similarly is present for embryonic stem cell-derived cardiomyocytes. This analysis provides compelling evidence that myofibrillar structure should be quantified and controlled for in studies investigating contractile function in iPSC-CMs.

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Rahul S. Deshmukh ◽  
Krisztián A Kovács ◽  
András Dinnyés

Development of induced pluripotent stem cells (iPSCs) using forced expression of specific sets of transcription factors has changed the field of stem cell research extensively. Two important limitations for research application of embryonic stem cells (ESCs), namely, ethical and immunological issues, can be circumvented using iPSCs. Since the development of first iPSCs, tremendous effort has been directed to the development of methods to increase the efficiency of the process and to reduce the extent of genomic modifications associated with the reprogramming procedure. The established lineage-specific differentiation protocols developed for ESCs are being applied to iPSCs, as they have great potential in regenerative medicine for cell therapy, disease modeling either for drug development or for fundamental science, and, last but not least, toxicity testing. This paper reviews efforts aimed at practical development of iPSC differentiation to neural/cardiac lineages and further the use of these iPSCs-derived cells for drug development and toxicity testing.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xinyuan Zhang ◽  
Liang Ye ◽  
Hao Xu ◽  
Qin Zhou ◽  
Bin Tan ◽  
...  

Abstract Background Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) hold great promise for regenerative medicine and in drugs screening. Despite displaying key cardiomyocyte phenotypic characteristics, they more closely resemble fetal/neonatal cardiomyocytes and are still immature; these cells mainly rely on glucose as a substrate for metabolic energy, while mature cardiomyocytes mainly employ oxidative phosphorylation of fatty acids. Studies showed that the alteration of metabolism pattern from glycolysis to oxidative phosphorylation improve the maturity of hiPSC-CMs. As a transcription factor, accumulating evidences showed the important role of NRF2 in the regulation of energy metabolism, which directly regulates the expression of mitochondrial respiratory complexes. Therefore, we hypothesized that NRF2 is involved in the maturation of hiPSC-CMs. Methods The morphological and functional changes related to mitochondria and cell maturation were analyzed by knock-down and activation of NRF2. Results The results showed that the inhibition of NRF2 led to the retardation of cell maturation. The activation of NRF2 leads to a more mature hiPSC-CMs phenotype, as indicated by the increase of cardiac maturation markers, sarcomere length, calcium transient dynamics, the number and fusion events of mitochondria, and mitochondrial respiration. Bioinformatics analysis showed that in addition to metabolism-related genes, NRF2 also activates the expression of myocardial ion channels. Conclusions These findings indicated that NRF2 plays an important role in the maturation of hiPSC-CMs. The present work provides greater insights into the molecular regulation of hiPSC-CMs metabolism and theoretical basis in drug screening, disease modeling, and alternative treatment.


2021 ◽  
Vol 22 (7) ◽  
pp. 3311
Author(s):  
Satish Kumar ◽  
Joanne E. Curran ◽  
Kashish Kumar ◽  
Erica DeLeon ◽  
Ana C. Leandro ◽  
...  

The in vitro modeling of cardiac development and cardiomyopathies in human induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CMs) provides opportunities to aid the discovery of genetic, molecular, and developmental changes that are causal to, or influence, cardiomyopathies and related diseases. To better understand the functional and disease modeling potential of iPSC-differentiated CMs and to provide a proof of principle for large, epidemiological-scale disease gene discovery approaches into cardiomyopathies, well-characterized CMs, generated from validated iPSCs of 12 individuals who belong to four sibships, and one of whom reported a major adverse cardiac event (MACE), were analyzed by genome-wide mRNA sequencing. The generated CMs expressed CM-specific genes and were highly concordant in their total expressed transcriptome across the 12 samples (correlation coefficient at 95% CI =0.92 ± 0.02). The functional annotation and enrichment analysis of the 2116 genes that were significantly upregulated in CMs suggest that generated CMs have a transcriptomic and functional profile of immature atrial-like CMs; however, the CMs-upregulated transcriptome also showed high overlap and significant enrichment in primary cardiomyocyte (p-value = 4.36 × 10−9), primary heart tissue (p-value = 1.37 × 10−41) and cardiomyopathy (p-value = 1.13 × 10−21) associated gene sets. Modeling the effect of MACE in the generated CMs-upregulated transcriptome identified gene expression phenotypes consistent with the predisposition of the MACE-affected sibship to arrhythmia, prothrombotic, and atherosclerosis risk.


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.


2021 ◽  
Author(s):  
T. Hang Nghiem-Rao ◽  
Courtney Pfeifer ◽  
Michelle Asuncion ◽  
Joshua Nord ◽  
Daniel Schill ◽  
...  

Abstract Parenteral nutrition-associated cholestasis (PNAC) significantly limits the safety of intravenous parenteral nutrition (PN). Critically ill infants are highly vulnerable to PNAC-related morbidity and mortality, however the impact of hepatic immaturity on PNAC is poorly understood. We examined developmental differences between fetal/infant and adult livers, and used human induced pluripotent stem cell-derived hepatocyte-like cells (iHLC) to gain insights into the contribution of development to altered sterol metabolism and PNAC. We used RNA-sequencing and computational techniques to compare gene expression patterns in human fetal/infant livers, adult liver, and iHLC. We identified distinct gene expression profiles between the human feta/infant livers compared to adult liver, and close resemblance of iHLC to human developing livers. Compared to adult, both developing livers and iHLC had significant downregulation of xenobiotic, bile acid, and fatty acid metabolism; and lower expression of the sterol metabolizing gene ABCG8. When challenged with stigmasterol, a plant sterol found in intravenous soy lipids, lipid accumulation was significantly higher in iHLC compared to adult-derived HepG2 cells. Our findings provide insights into altered bile acid and lipid metabolizing processes in the immature human liver, and support the use of iHLC as a relevant model system of developing liver to study lipid metabolism and PNAC.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Wenyi Chen ◽  
Johannes Riegler ◽  
Elena Matsa ◽  
Qi Shen ◽  
Haodi Wu ◽  
...  

Introduction: Both human embryonic stem cell-derived cardiomyocytes (ESC-CMs) and human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) can serve as an unlimited cell source for cardiac regenerative therapy. However, the functional equivalency of both approaches has not been previously reported. Here we performed head-to-head comparison on the beneficial effects of ESC-CM and iPSC-CMs in restoring cardiac function in a rat myocardial infarction (MI) model. Methods & Results: Human ESCs and iPSCs were differentiated into cardiomyocytes using small molecules. FACS analysis confirmed ~85% and ~83% of cells differentiated from ESCs and iPSCs, respectively, were positive for cardiac troponin T, and immunofluorescence staining demonstrated that ESC-CMs and iPSC-CMs have striated sarcomeric structure (Figure A-B). Both ESC-CMs and iPSC-CMs displayed similar maturity for calcium handling (transient amplitude: ΔF/F 0 = 3.8±0.3; time to peak: ~200 ms; 50% transient duration: ~400 ms). qRT-PCR showed that ESC-CMs and iPSC-CMs expressed CASQ2, GJA5, KCNJ2, KCNJ5, MYH6, MYH7, and SCN5A at comparable levels to human fetal heart tissue. Next, ESC-CMs and iPSC-CMs were injected into the left ventricular free wall of infarcted hearts (adult nude rats; n=14, 10, respectively). Cardiac function was assessed by MRI one month post cell injection and the hearts were harvested and stained for human cardiac markers. Both ESC-CMs and iPSC-CMs could engraft in ischemic rat hearts (Figure C). Comprehensive functional analysis with small animal magnetic resonance imaging (MRI), echocardiography, and pressure-volume loop analysis are underway. Conclusion: We set out to perform head to head comparison for the first time that iPSC-CMs may facilitate cardiac repair at comparable levels to ESC-CMs. Unlike allogeneic ESC-CM therapy, autologous iPSC-CMs could be used to overcome immune rejection for cardiac cell transplantation in the future.


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.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Farzaneh Rami ◽  
Halimeh Mollainezhad ◽  
Mansoor Salehi

The immune system consists of cells, proteins, and other molecules that beside each other have a protective function for the host against foreign pathogens. One of the most essential features of the immune system is distinguishability between self- and non-self-cells. This function has an important role in limiting development and progression of cancer cells. In this case, the immune system can detect tumor cell as a foreign pathogen; so, it can be effective in elimination of tumors in their early phases of development. This ability of the immune system resulted in the development of a novel therapeutic field for cancer treatment using host immune components which is called cancer immunotherapy. The main purpose of cancer immunotherapy is stimulation of a strong immune response against the tumor cells that can result from expressing either the immune activator cytokines in the tumor area or gene-modified immune cells. Because of the problems of culturing and manipulating immune cells ex vivo, in recent years, embryonic stem cell (ESC) and induced pluripotent stem cell (iPSC) have been used as new sources for generation of modified immune stimulatory cells. In this paper, we reviewed some of the progressions in iPSC technology for cancer immunotherapy.


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