Browsing by Author "Leu, Hsin-Bang"

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Enhancing induced pluripotent stem cell toward differentiation into functional cardiomyocytes
(2020-07-01)
Chien, Chian-Shiu
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Wang, Chien-Ying
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Leu, Hsin-Bang
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Chien, Yueh
;
Yang, Yi-Ping
Background: Heart diseases, especially myocardial ischemia, remain one of the leading causes of mortality worldwide and usually result in irreparable cardiomyocyte damage and severe heart failure. Recent advances in induced pluripotent stem cell (iPSC) technologies for applied regenerative medicine and stem cell research, especially for iPSC-derived cardiomyocytes have increased the hope for heart repair. However, the driver molecules of myocardial differentiation and the functional reconstruction capacity of iPSC-derived cardiomyocytes are still questionable. Methods: Herein, we established a rapid differentiated platform that is involved in cardiomyogenic differentiation and maturation from iPSCs in vitro. Functional analysis is performed in miR-181a-transfected iPSC-derived cardiomyocyte (iPSC-cardio/miR-181a) under a time-lapse microscope. In addition, we calculated the beating area and frequency of iPSC-cardio/miR-181a cells in the presence of HCN4 shRNA or miR-181a SPONGE. Results: miR-181a enhanced the beating area and maintained the beating frequency of iPSC-derived cardiomyocytes by enhancing HCN4 expression. Conclusion: miR-181a would play a key role on maintaining proper beating function in iPSC-derived cardiomyocytes.
Imbalanced Production of Reactive Oxygen Species and Mitochondrial Antioxidant SOD2 in Fabry Disease-Specific Human Induced Pluripotent Stem Cell-Differentiated Vascular Endothelial Cells
(2017-01-01)
Tseng, Wei-Lien
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Chou, Shih-Jie
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Chiang, Huai-Chih
;
Wang, Mong-Lien
;
Chien, Chian-Shiu
Fabry disease (FD) is an X-linked inherited lysosomal storage disease caused by alpha-galactosidase A (GLA) deficiency. Progressive intracellular accumulation of globotriaosylceramide (Gb3) is considered to be pathogenically responsible for the phenotype variability of FD that causes cardiovascular dysfunction; however, molecular mechanisms underlying the impairment of FD-associated cardiovascular tissues remain unclear. In this study, we reprogrammed human induced pluripotent stem cells (hiPSCs) from peripheral blood cells of patients with FD (FD-iPSCs); subsequently differentiated them into vascular endothelial-likecells (FD-ECs) expressing CD31, VE-cadherin, and vWF; and investigated their ability to form vascular tube-like structures. FD-ECs recapitulated the FD pathophysiological phenotype exhibiting intracellular Gb3 accumulation under a transmission electron microscope. Moreover, compared with healthy control iPSC-derived endothelial cells (NC-ECs), reactive oxygen species (ROS) production considerably increased in FD-ECs. Microarray analysis was performed to explore the possible mechanism underlying Gb3 accumulation-induced ROS production in FD-ECs. Our results revealed that superoxide dismutase 2 (SOD2), a mitochondrial antioxidant, was significantly downregulated in FD-ECs. Compared with NC-ECs, AMPK activity was significantly enhanced in FD-ECs. Furthermore, to investigate the role of Gb3 in these effects, human umbilical vein endothelial cells (HUVECs) were treated with Gb3. After Gb3 treatment, we observed that SOD2 expression was suppressed and AMPK activity was enhanced in a dose-dependent manner. Collectively, our results indicate that excess accumulation of Gb3 suppressed SOD2 expression, increased ROS production, enhanced AMPK activation, and finally caused vascular endothelial dysfunction. Our findings suggest that dysregulated mitochondrial ROS may be a potential target for treating FD.
Interleukin-18 deteriorates Fabry cardiomyopathy and contributes to the development of left ventricular hypertrophy in Fabry patients with GLA IVS4+919 G>A mutation
(2016-12-27)
Chien, Yueh
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Chien, Chian-Shiu
;
Chiang, Huai-Chih
;
Huang, Wei-Lin
;
Chou, Shih-Jie
Rationale: A high incidence of GLA IVS4+919 G>A mutation in patients with Fabry disease of the later-onset cardiac phenotype, has been reported in Taiwan. However, suitable biomarkers or potential therapeutic surrogates for Fabry cardiomyopathy (FC) in such patients under enzyme replacement treatment (ERT) remain unknown. Objective: Using FC patients carrying IVS4+919 G>A mutation, we constructed an induced pluripotent stem cell (iPSC)-based disease model to investigate the pathogenetic biomarkers and potential therapeutic targets in ERT-treated FC. Results and methods: The iPSC-differentiated cardiomyocytes derived from FC-patients (FC-iPSC-CMs) carried IVS4+919 G>A mutation recapitulating FC characteristics, including low a-galactosidase A enzyme activity, cellular hypertrophy, and massive globotriaosylceramide accumulation. Microarray analysis revealed that interleukin-18 (IL-18), a pleiotropic cytokine involved in various myocardial diseases, was the most highly upregulated marker in FC-iPSC-CMs. Meanwhile, IL-18 levels were found to be significantly elevated in the culture media of FC-iPSC-CMs and patients\' sera. Notably, the serum IL-18 levels were highly paralleled with the progression of left ventricular hypertrophy in Fabry patients receiving ERT. Finally, using FC-iPSC-CMs as in vitro FC model, neutralization of IL-18 with specific antibodies combined with ERT synergistically reduced the secretion of IL-18 and the progression of cardiomyocyte hypertrophy in FC-iPSC-CMs. Conclusion: Our data demonstrated that cardiac IL-18 and circulating IL-18 are involved in the pathogenesis of FC and LVH. IL-18 may be a novel marker for evaluating ERT efficacy, and targeting IL-18 might be a potential adjunctive therapy combined with ERT for the treatment of advanced cardiomyopathy in FC patients with IVS4+919 G>A mutation.