To advance drug discovery for cardiovascular patients, new pre-clinical models and quantification methods are needed to improve clinical predictivity. This thesis aims to explore several approaches... Show moreTo advance drug discovery for cardiovascular patients, new pre-clinical models and quantification methods are needed to improve clinical predictivity. This thesis aims to explore several approaches to bringing new solutions for disease modeling which reflect the human heart. Firstly, we review the current status of the Heart-on-chip (HoC) field and the cutting edge (bio)materials which enable more physiologically relevant culture methods for stem cell-derived cardiomyocytes (hiPSC-CMs). Then, we use a polydimethylsiloxane chip to culture hiPSC-CM, hiPSC-endothelial cells and hiPSC-cardiac fibroblasts combined with a microfluidic flow-channel to mimic physiological blood flow. Subsequently, we fabricated and tested a platform for 3D-culture of heart tissues designed ultimately for medium- to high-throughput drug screening. Moreover, we create a stand-alone software application for automated and robust analysis of in vitro models of striated muscle. We have used a previously published mathematical tool and applied it to static, live, 2D, 3D, hiPSC-CM, primary CM and skeletal muscle, providing evidence of its versatility. This was successfully applied to study hiPSC-CMs from patients with hypertrophic cardiomyopathy and carrying a heterozygous mutation in the MYBPC3 gene. Finally, we discuss the results and conclusions presented in this thesis, and provide an outlook of future research directions in this exciting field. Show less
We synthesized and evaluated three novel series of substituted benzophenones for their allosteric modulation of the human K(v)11.1 (hERG) channel. We compared their effects with reference compound... Show moreWe synthesized and evaluated three novel series of substituted benzophenones for their allosteric modulation of the human K(v)11.1 (hERG) channel. We compared their effects with reference compound LUF7346 previously shown to shorten the action potential of cardiomyocytes derived from human stem cells. Most compounds behaved as negative allosteric modulators (NAMs) of [H-3]dofetilide binding to the channel. Compound 9i was the most potent amongst all ligands, remarkably reducing the affinity of dofetilide in competitive displacement assays. One of the other derivatives (6k) tested in a second radioligand binding set-up, displayed unusual displacement characteristics with a pseudo-Hill coefficient significantly distinct from unity, further indicative of its allosteric effects on the channel. Some compounds were evaluated in a more physiologically relevant context in beating cardiomyocytes derived from human induced pluripotent stem cells. Surprisingly, the compounds tested showed effects quite different from the reference NAM LUF7346. For instance, compound 5e prolonged, rather than shortened, the field potential duration, while it did not influence this parameter when the field potential was already prolonged by dofetilide. In subsequent patch clamp studies on HEK293 cells expressing the hERG channel the compounds behaved as channel blockers. In conclusion, we successfully synthesized and identified new allosteric modulators of the hERG channel. Unexpectedly, their effects differed from the reference compound in functional assays on hERG-HEK293 cells and human cardiomyocytes, to the extent that the compounds behaved as stand-alone channel blockers. (C) 2020 The Author(s). Published by Elsevier Masson SAS. Show less
