Human in vitro disease modeling of ATTR cardiac amyloidosis

Abstract

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Pfizer Alnylam Transthyretin amyloid cardiomyopathy (ATTR-CM) is a progressive disease with deposition of TTR amyloid fibrils in the myocardium and cardiac dysfunction with dismal prognosis. In ATTR-CM, either genetic mutations (variant; v) or ageing (wild-type; wt) leads to TTR instability. Late diagnosis and a lack of human disease models limit disease understanding and therapeutic discovery. This study aimed to model ATTR-CM in vitro by exposing various cardiac cell types and multicellular 3D cardiac spheroids to TTR fibrils, characterizing disease phenotypes and providing insights into the cellular mechanisms of disease progression. Human recombinant TTR (WT, V30M, V122I) and acid induced fibrils were generated and characterized. Seeding hiPSC-cardiomyocytes (CMs) and endothelial cells (ECs) on TTR fibrils resulted in cell viability reduction. Confocal microscopy revealed the extracellular attachment of TTR fibrils, leading to sarcomere disorganization, prolonged calcium transients and disrupted electromechanical coupling in hiPSC-CMs, and declined migration capacity of ECs showing aberrant cell morphology. Similarly, cardiac spheroids incorporating TTR fibrils resulted in decreased cell viability and prolonged calcium transients with lower amplitude. Our models show the discovery of early cellular ATTR-CM phenotypes, providing a novel approach to study the disease progression, potentially facilitating the identification of novel therapeutic targets and biomarkers.Cytotoxicity of TTR fibrils on hiPS-CMs