Abstract P449: Connexin43 As A Therapeutic For Arrhythmogenic Right Ventricular Cardiomyopathy

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Jing Zhang ◽  
Fabian Zanella ◽  
William H Bradford ◽  
Kyohei Fujita ◽  
Ioannis Karakikes ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Arrhythmogenic Right Ventricular Cardiomyopathy ◽  
Induced Pluripotent Stem Cell ◽  
Structural Defects ◽  
Cell Junction ◽  
Gene Expressions ◽  
Molecular Alteration ◽  
Structural Alterations ◽  
Junction Protein

Limited efforts have been focused on the interventions which could therapeutically alter arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C), a fatal cardiac disease of the desmosomal (mechanical) cell-cell junction. The desmosome is a critical target for intervention as mutations in desmosomal genes underlie 40-50% of ARVD/C populations and its dysregulation is associated with severe cardiac electrical and structural alterations, which facilitate myocardial failure, arrhythmias and premature death in these populations. Cardiomyocyte reduction of the predominant ventricular gap junction protein connexin43 is a molecular alteration that underlies desmosomal deficits and arrhythmias in ARVD/C. However, the role of connexin43 in structural alterations associated with ARVD/C remains unclear. We intervened with connexin43 reduction in human and mouse models of ARVD/C via connexin43 restoration strategies, which revealed beneficial effects in both ARVD/C models. We show ARVD/C human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes that recapitulate desmosomal structural defects and reveal connexin43 diminution alterations that are reflective of disease found in donor ARVD/C hearts. Connexin43 restoration was sufficient to rescue cardiac physiological deficits and increase desmosomal gene expressions in ARVD/C hiPSC derived cardiomyocytes, encompassing structural alterations. In vivo studies exploiting a mouse model of ARVD/C harboring severe desmosomal structural alterations revealed that cardiac connexin43 restoration was sufficient to prolong lifespan and restore cardiac desmosomal proteins. Herein, we provide evidence for non-canonical functions for connexin43, classically associated with electrical function, in the mechanical modulation of junctions. Our findings have broad implications in exploiting connexin43 as a therapeutic in advanced diseases associated with cardiac structural defects.

Abstract 11078: Granzyme B Deficiency Protects Against Angiotensin II-induced Cardiac Fibrosis via a Perforin-independent Mechanism

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Yue Shen ◽  
Fang Cheng ◽  
Mehul Sharma ◽  
Yulia Merkulova ◽  
Sheetal A Raithatha ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Cardiac Fibrosis ◽  
Granzyme B ◽  
Cell Junction ◽  
Pcr Analysis ◽  
Ang Ii ◽  
Junction Protein ◽  
Independent Process

Introduction: Granzyme B (GzmB) is a serine protease involved in immune cell-mediated apoptosis that is enabled through a mechanism involving the pore-forming protein, perforin that facilitates internalization. However, recent evidence suggests that GzmB contributes to matrix remodeling and fibrosis through an extracellular, perforin-independent process. Hypothesis: GzmB contributes to cardiac fibrosis through a perforin-independent pathway involving extracellular proteolysis. Methods: Using a murine model of Angiotensin II (Ang II)-induced cardiac fibrosis, wild-type, GzmB deficient and Perforin deficient mice were treated with Ang II for 4 weeks, and were examined for the presence of cardiac fibrosis. Echocardiography was performed in these mice to examine the cardiac function. The level of Inflammation and inflammatory cells infiltration were examined by immunohistochemistry and RT-PCR analysis. The in vitro endothelial barrier function was measured by electric cell-substrate impedance sensing. Results: GzmB was highly up-regulated in both murine and human cardiac fibrosis. Genetic deficiency of GzmB markedly reduced Ang II-induced cardiac dysfunction, hypertrophy and fibrosis, independently of perforin. GzmB deficiency also decreases microhemorrhage, inflammation, and fibroblast accumulation in vivo. In vitro studies identified VE-cadherin as a GzmB substrate. VE-cadherin is a key endothelial cell-cell junction protein. GzmB-mediated VE-cadherin cleavage resulted in increased endothelial permeability, and increased transcellular conductance. These results were also observed in vivo. Conclusions: GzmB contributes to the onset and progression of cardiac fibrosis through a perforin-independent process involving the cleavage of VE-cadherin.

scholarly journals Induced Pluripotent Stem Cell-Differentiated Chondrocytes Repair Cartilage Defect in a Rabbit Osteoarthritis Model

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Yu-Hsun Chang ◽  
Kun-Chi Wu ◽  
Dah-Ching Ding
Keyword(s):  
Stem Cell ◽  
Therapeutic Effect ◽  
Embryoid Body ◽  
Cruciate Ligament ◽  
Induced Pluripotent Stem Cell ◽  
Cartilage Defects ◽  
Gene Expressions ◽  
Induced Pluripotent ◽  
Teratoma Formation

The aim of this study was to explore the therapeutic effect of iPSC-mesenchymal stem cell (MSC)-derived chondrocytes in a rabbit osteoarthritis (OA) model. The iPSCs were characterized by gene expressions, immunostaining of pluripotent markers, and in vivo teratoma formation. iPSC-differentiated MSCs were characterized by flow cytometry and trilineage differentiation. A rabbit OA model was established by the transection of the anterior cruciate ligament. The therapeutic effect of transplanted iPSC-MSC-chondrocytes on the OA was evaluated by the histology, immunostaining, and qPCR of defective cartilage. The results showed iPSC could express pluripotency markers such as OCT4, SOX2, and NANOG and form an embryoid body and a teratoma. After differentiation of iPSCs for 30 days, MSCs were established. The iPSC-MSC could express typical MSC markers such as CD29, CD44, CD90, CD105, and HLA-ABC. They could differentiate into adipocytes, osteocytes, and chondrocytes. In this model, iPSC-MSC-chondrocytes significantly improved the histology and ICRS (International Cartilage Repair Society) scores. The transplanted cartilage expressed less IL-1β, TNF-α, and MMP13 than control cartilage. In conclusion, the iPSCs we derived might represent an emerging source for differentiated MSC-chondrocyte and might rescue cartilage defects through its anti-inflammatory and anti-catabolic effects.

Arrhythmogenic right ventricular cardiomyopathy: severe structural alterations are associated with inflammation

2012 ◽  
Vol 65 (12) ◽  
pp. 1077-1083 ◽  
Author(s):  
Oscar Campuzano ◽  
Mireia Alcalde ◽  
Anna Iglesias ◽  
Catherine Barahona-Dussault ◽  
Georgia Sarquella-Brugada ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Arrhythmogenic Right Ventricular Cardiomyopathy ◽  
Ventricular Cardiomyopathy ◽  
Structural Alterations

scholarly journals Nucleoside Diphosphate Kinase B Contributes to Arrhythmogenesis in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes from a Patient with Arrhythmogenic Right Ventricular Cardiomyopathy

2020 ◽  
Vol 9 (2) ◽  
pp. 486 ◽  
Author(s):  
Fanis Buljubasic ◽  
Ibrahim El-Battrawy ◽  
Huan Lan ◽  
Santosh K. Lomada ◽  
Anupriya Chatterjee ◽  
...  
Keyword(s):  
Stem Cell ◽  
Right Ventricular ◽  
Pluripotent Stem Cell ◽  
Arrhythmogenic Right Ventricular Cardiomyopathy ◽  
Nucleoside Diphosphate Kinase ◽  
Induced Pluripotent Stem Cell ◽  
Occurrence Rate ◽  
Ventricular Cardiomyopathy ◽  
Nucleoside Diphosphate Kinase B ◽  
Induced Pluripotent

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare, inheritable cardiac disorder characterized by ventricular tachyarrhythmias, progressive loss of cardiomyocytes with fibrofatty replacement and sudden cardiac death. The exact underlying mechanisms are unclear. Methods: This study investigated the possible roles of nucleoside diphosphate kinase B (NDPK-B) and SK4 channels in the arrhythmogenesis of ARVC by using human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Results: In hiPSC-CMs from a patient with ARVC, the expression levels of NDPK-B and SK4 channels were upregulated, the cell automaticity was increased and the occurrence rate of arrhythmic events was enhanced. Recombinant NDPK-B applied into hiPSC-CMs from either healthy donors or the patient enhanced SK4 channel current (ISK4), cell automaticity and the occurrence of arrhythmic events, whereas protein histidine phosphatase 1 (PHP-1), a counter actor of NDPK-B, prevented the NDPK-B effect. Application of PHP-1 alone or a SK4 channel blocker also reduced cell automaticity and arrhythmic events. Conclusion: This study demonstrated that the elevated NDPK-B expression, via activating SK4 channels, contributes to arrhythmogenesis in ARVC, and hence, NDPK-B may be a potential therapeutic target for treating arrhythmias in patients with ARVC.

scholarly journals iASPP, a previously unidentified regulator of desmosomes, prevents arrhythmogenic right ventricular cardiomyopathy (ARVC)-induced sudden death

2015 ◽  
Vol 112 (9) ◽  
pp. E973-E981 ◽  
Author(s):  
Mario Notari ◽  
Ying Hu ◽  
Gopinath Sutendra ◽  
Zinaida Dedeić ◽  
Min Lu ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Molecular Mechanisms ◽  
Arrhythmogenic Right Ventricular Cardiomyopathy ◽  
Spontaneous Mutation ◽  
Ventricular Cardiomyopathy ◽  
Intercalated Discs ◽  
Frequent Mutations ◽  
Filament Networks

Desmosomes are anchoring junctions that exist in cells that endure physical stress such as cardiac myocytes. The importance of desmosomes in maintaining the homeostasis of the myocardium is underscored by frequent mutations of desmosome components found in human patients and animal models. Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a phenotype caused by mutations in desmosomal components in ∼50% of patients, however, the causes in the remaining 50% of patients still remain unknown. A deficiency of inhibitor of apoptosis-stimulating protein of p53 (iASPP), an evolutionarily conserved inhibitor of p53, caused by spontaneous mutation recently has been associated with a lethal autosomal recessive cardiomyopathy in Poll Hereford calves and Wa3 mice. However, the molecular mechanisms that mediate this putative function of iASPP are completely unknown. Here, we show that iASPP is expressed at intercalated discs in human and mouse postmitotic cardiomyocytes. iASPP interacts with desmoplakin and desmin in cardiomyocytes to maintain the integrity of desmosomes and intermediate filament networks in vitro and in vivo. iASPP deficiency specifically induces right ventricular dilatation in mouse embryos at embryonic day 16.5. iASPP-deficient mice with exon 8 deletion (Ppp1r13lΔ8/Δ8) die of sudden cardiac death, displaying features of ARVC. Intercalated discs in cardiomyocytes from four of six human ARVC cases show reduced or loss of iASPP. ARVC-derived desmoplakin mutants DSP-1-V30M and DSP-1-S299R exhibit weaker binding to iASPP. These data demonstrate that by interacting with desmoplakin and desmin, iASPP is an important regulator of desmosomal function both in vitro and in vivo. This newly identified property of iASPP may provide new molecular insight into the pathogenesis of ARVC.

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