Engineering epicardium-integrated human iPSC-derived heart tissue for modelling Hutchinson-Gilford progeria syndrome.

Abstract

Engineered heart tissues (EHT) have been utilized in research for almost three decades and have become an important tool in cardiovascular research to address the shortcomings of the interspecies issues of animal models and oversimplicity of single cell type two-dimensional cell models to recapitulate cardiac (patho)physiology. Recently, epicardium-integrated EHT models have emerged in research as therapeutic applications for remuscularizing the failing heart. Epicardium is the outermost mesothelial layer of the heart and plays a central role in heart development and pathophysiology. It acts as a source of progenitor cells, thus contributing to cardiac fibroblast (CF), vascular smooth muscle cell (VSMC) and pericyte populations in heart, and participates in essential signalling by secreting factors guiding cardiomyocyte growth and maturation. In this study, we developed an epicardium-integrated EHT to allow more physiologically relevant modelling of Hutchinson-Gilford Progeria Syndrome (HGPS), a laminopathy caused by a single point mutation in LMNA gene leading to expression of truncated Lamin A protein called progerin. HGPS causes premature aging-like symptoms with severe cardiac phenotype, to which CF and VSMC have a significant contribution to. In our model, we observed that the epicardial cells (EPI) differentiate into CF and VSMC, allowing incorporation of these crucial cell types to our model. We showed that the EPI-integrated EHT started to express progerin and the HGPS phenotype within 60 days of culture. Gene set enrichment was observed in genes related to atherosclerosis, apoptosis and fibrosis, as well as oxidative stress, which are known hallmarks of HGPS and also related to normal aging. Furthermore, we observed a culture-time related decrease in the EHT response to pacing. Taken together, our results indicate that the presented EHT model could be used for further evaluating HGPS disease mechanisms and treatments, as well as adapted for modelling other cardiovascular diseases and therapeutic applications.