Abstract Body: Introduction: Heart failure, which is one of the leading causes of death worldwide, is characterized by the irreversible loss of cardiomyocytes (CMs). Over the past few decades, there has been significant interest in exploring strategies to revive the inherent regenerative potential of the heart for repairing the damaged heart tissue. While various approaches to promote cardiac regeneration in vivo involving direct reprogramming to induced cardiomyocytes (iCMs) or induction of CM proliferation have been proposed, they are limited by strikingly low efficiency or negative impacts on heart function. Our lab has conducted an unbiased phenotypic screening and identified a group of structurally related small molecules that enhance proliferation in human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs).
Methods and Results:
We performed a CM proliferation screen using compounds that had been previously identified as Wnt/β-catenin activators and analogues. The analogues DF6 and LRN9 were found to significantly upregulate the percent positive levels of Ki-67, EdU, and pHH3 CMs following treatment for 72 hours. Interestingly, more mature D30 cardiomyocytes responded better to LRN9 than DF6, as indicated by higher numbers of EdU+ and pHH3+ CMs following LRN9 treatment. In 3D cardiac organoids, both DF6 and LRN9 treatment significantly increased Ki-67+ cardiomyocytes, with DF6 showing the greatest effect. Notably, treatment with LRN9 resulted in no significant changes to force, activation time or relaxation time in the 3D organoids. GO-term enrichment analysis of RNA-seq data revealed upregulation of DNA replication, DNA repair, and cell division processes following LRN9 treatment. Using the Eurofins kinase screening platform, we found that DF6 and LRN9 target 14 and 39 kinases, respectively, at 10 µM, with high selectivity scores of 0.035 and 0.097.
Conclusions: This study identifies a novel therapeutic target for inducing iPSC-CM proliferation and reveals potential lead compounds for future regenerative therapies.