RT Journal Article T1 Overexpression of Wild-Type TMEM43 Improves Cardiac Function in Arrhythmogenic Right Ventricular Cardiomyopathy Type 5 A1 Lalaguna, Laura A1 Arévalo Núñez de Arenas, María A1 López Olañeta, Marina A1 Villalba Orero, María A1 Jiménez Riobóo, Rafael J. A1 Gómez Gaviro, María Victoria A1 Isern, Joan A1 Muñoz Cánoves, Pura A1 Byrne, Barry J. A1 Ochoa, Juan Pablo A1 García Pavía, Pablo A1 Lara Pezzi, Enrique AB Background: Arrhythmogenic right ventricular cardiomyopathy type 5 (ARVC5) is the most aggressive type of ARVC, caused by a fully penetrant missense mutation (p.S358L) in TMEM43 (transmembrane protein 43). Pathologically, the disease is characterized by dilation of the cardiac chambers and fibrofatty replacement of the myocardium, which results in heart failure and sudden cardiac death. Current therapeutic options are limited, and no specific therapies targeting the primary cause of the disease have been proposed.Methods: We investigated whether overexpression of wild-type (WT) TMEM43 could overcome the detrimental effects of the mutant form. We used transgenic mouse models overexpressing either WT or mutant (S358L) TMEM43 to generate a double transgenic mouse line overexpressing both forms of the protein. In addition, we explored if systemic delivery of a codon-optimized self-complementary adeno-associated virus bearing WT-TMEM43 could improve disease progression assessed by ECG and echocardiography.Results: Double transgenic mice overexpressing both WT and mutant TMEM43 forms showed delayed ARVC5 onset, improved cardiac contraction, and reduced ECG abnormalities compared with mice expressing S358L-TMEM43. In addition, cardiomyocyte death and myocardial fibrosis were reduced, with an overall increase in survival. Finally, we demonstrated that a single systemic administration of an adeno-associated virus carrying codon-optimized WT-TMEM43 prevents ventricular dysfunction and ECG abnormalities induced by S358L-TMEM43.Conclusions: Overexpression of WT-TMEM43 improves the pathological phenotype in a mouse model of ARVC5. Adeno-associated virus-mediated delivery of WT-TMEM43 offers a promising and specific therapy for patients suffering from this highly lethal disease. PB Lippincott Williams & Wilkins SN 0009-7330 YR 2025 FD 2025-04-11 LK https://hdl.handle.net/20.500.14352/121605 UL https://hdl.handle.net/20.500.14352/121605 LA eng NO European Commission NO Ministerio de Ciencia, Innovación y Universidades (España) NO Instituto de Salud Carlos III DS Docta Complutense RD 26 feb 2026