Engineering hiPSC-derived tissue models for advanced amyloidosis research and therapy development

Abstract Introduction Transthyretin (TTR) amyloid cardiomyopathy (ATTR-CM) is a life-threatening disease currently lacking an optimal therapy, stemming from the absence of representative models. Our work aims to stablish for the first time an all-human 3D model of ATTR-CM where the main cellular and extracellular players of the pathology are present. Methodology A human induced pluripotent stem cell (hiPSC) line was derived from a patient carrying a p.Ser43Asn TTR mutation and differentiated into hepatocytes (hiPSC-HEPs), cardiomyocytes (hiPSC-CMs) and cardiac fibroblasts (hiPSC-CFs). Cells were embedded in a hydrogel (tailored for each cell type) and combined with a designed 3D printed scaffold using Melt Electro Writing (MEW) technology. Tissues were maintained in culture for up to 4 weeks and characterized by staining, albumin production, electrophysiological, plus genomic analysis. Exposure to TTR fibrils (TTR-FIB) was evaluated. Results Human hepatic and cardiac functional tissues can be generated using MEW-designs. These constructs exhibited albumin production and an active spontaneous contraction, respectively. Moreover, tissues displayed well distributed cells throughout the 3D-structure, positive for specific hepatic and cardiac mature markers. Interestingly, electrophysiological analysis showed that cardiac tissues displayed shortened calcium transients after TTR-FIB exposure compared to unexposed tissues. However, no differences were found in terms of beat rate, metabolic activity and gene expression for the concentrations used. Conclusion We have developed an advanced model of ATTR-CM capable of recapitulating the multisystem complexity of the disease, which will contribute to advancing our understanding of the mechanisms of the disease, and help discovering and formulating new treatments.