Introduction:: Cardiovascular diseases are the leading causes of death worldwide, and the inability of the adult heart to regenerate results in prevalent morbidity and mortality related to myocardial infarction and heart failure. Currently, proposed cardiac therapies to repair the injured heart and improve heart function do not correct the loss of cardiomyocytes (CMs), and the prognosis of heart failure remains poor. Therefore, there is a strong need for therapeutic strategies that increase CM proliferation to restore heart function and improve survival and disease outcomes. Our lab has previously developed a model of CM proliferation signaling that has identified potential therapeutic regulators that induce CM proliferation and has been experimentally validated [1]. Now, we aim to induce the proliferation of endogenous CMs by repurposing existing drugs that target signaling molecules and regulatory proteins known to mediate CM proliferation. To accomplish this, we used a computational model of CM proliferation signaling to identify drugs and network mechanisms that control CM proliferation. We hypothesize that FDA approved and investigational drugs induce context-dependent CM proliferation.
Materials and Methods:: A previously developed CM proliferation signaling network [1] was integrated with drug-target interactions from a publicly available database (DrugBank) to simulate the effect of drugs on 5 CM proliferation phenotypes (Binucleation, Cytokinesis, DNA Replication, Mitosis, and Polyploid) in up to 13 stimuli contexts. A virtual screen with knockdown combinations of regulators was used to identify signaling mechanisms responsible for mediating the effect of drugs, and literature validation was performed against published experimental data investigating the drugs or the drug targets in CMs. Neonatal rat CMs were treated with the YAP-activating drug TT10 or with FDA approved drugs identified in the virtual screen. Proliferation was measured by high-content microscopy and DNA replication and mitosis positive cells were identified from image analysis pipeline (CellProfiler) in order to discern CM proliferation from endoreplication (e.g. polyploid and binucleation).
Results, Conclusions, and Discussions:: Our pipeline for simulating drug signaling in a CM proliferation network model identified 16 unique drug-target interactions predicted to regulate CM proliferation phenotypes (Figure 1A). Four drugs (Ellagic Acid, Sucralfate, Lithium Cation, and Indirudin-3’-Monoxime) were predicted to increase CM phenotypic proliferation outputs and four drugs (Afatinib, Pentosan Polysulfate, Arsenic Trioxide, and Alpelisib) were predicted to decrease CM phenotypic proliferation outputs. Additionally, one drug (Fostmatinib) was predicted to upregulate DNA Replication and Polyploid while downregulating Binucleation, Mitosis, and Cytokinesis. Addition of TT10 drug (10 µM) induces proliferation in neonatal rat CMs as evidenced by increased Ki67 expression in cardiac Troponin T (cTnT) positive cells (Figure 1B). These results indicate a robust TT10-induced proliferation response that will be used as a positive control to validate other drug combination and mechanistic predictions. This work will identify drugs and network mechanisms that control CM proliferation. These studies will lead to a greater understanding of the cellular mechanisms driving CM proliferation and identify new therapeutic strategies for cardiac regeneration.
Acknowledgements (Optional): :
References (Optional): : 1. Harris et al., BioRxiv 2022.
