Year 2

The original goals of the proposal were to apply medicinal chemistry to generate more potent and drug-like analogs of small molecules that stimulate differentiation of cardiomyocytes from embryonic stem cell (ESC) and potentially other progenitor cell types found in adult human heart. During the grant period, we over-achieved each Aim and provided large numbers of drug-like small molecules for cardiomyocyte differentiation studies. In addition, other related information was gained that has considerably expanded our understanding related to developing regenerative medicines.

1. Synthetic Chemistry: From an initial screen of thousands of compounds, six ‘hits’ were identified. Almost 1300 compounds were synthesized as analogs of these “hits” with the goal of generating more effective novel compounds as possible therapeutics for heart disease.

2. Assay development and screening: Novel synthetic chemical analogs were studied in cell-based assays to evaluate potency of stimulating cardiac cell development relative to the starting ‘hit’ compounds. The biological data contributed to structure activity relationship (SAR) studies, and provided valuable information about parts of the molecules important for cardiomyocyte stem cell differentiation and for other important pharmaceutical properties. The iterative feedback from the biological testing helped to guide the next generation designs of new and ever more effective compounds.

3. Chemical optimization. Focused structure activity relationship (SAR) studies for 4 chemical series from the ESC cardiogenesis differentiation screen were done. SAR for 2 additional chemical classes was done but those agents proved less potent. In addition to SAR, considerable information was obtained leading to improved solubility and membrane permeability of compounds in development, which became a focus of the chemical optimizations.

In summary, the work has already led to one or more promising drug-like compounds ready for efficacy testing in animal models and thus, efforts have greatly accelerated the timeline of getting compounds to human patients.