Discovery of Novel Small-Molecule Inducers of Heme Oxygenase-1 That Protect Human iPSC-Derived Cardiomyocytes from Oxidative Stress

Abstract

Oxidative injury to cardiomyocytes plays a critical role in cardiac pathogenesis following myocardial infarction. Transplantation of stem cell-derived cardiomyocytes has recently progressed as a novel treatment to repair damaged cardiac tissue but its efficacy has been limited by poor survival of transplanted cells owing to oxidative stress in the post-transplantation environment. Identification of small molecules that activate cardioprotective pathways to prevent oxidative damage and increase survival of stem cells post-transplantation is therefore of great interest for improving the efficacy of stem cell therapies. This report describes a chemical biology phenotypic screening approach to identify and validate small molecules that protect human-induced pluripotent stem cell cardiomyocytes (hiPSC-CMs) from oxidative stress. A luminescence-based high-throughput assay for cell viability was used to screen a diverse collection of 48,640 small molecules for protection of hiPSC-CMs from peroxide-induced cell death. Cardioprotective activity of "hit" compounds was confirmed using impedance-based detection of cardiomyocyte monolayer integrity and contractile function. Structure-activity relationship studies led to the identification of a potent class of compounds with 4-(pyridine-2-yl)thiazole scaffold. Examination of gene expression in hiPSC-CMs revealed that the hit compound, designated cardioprotectant 312 (CP-312), induces robust upregulation of heme oxygenase-1, a marker of the antioxidant response network that has been strongly correlated with protection of cardiomyocytes from oxidative stress. CP-312 therefore represents a novel chemical scaffold identified by phenotypic high-throughput screening using hiPSC-CMs that activates the antioxidant defense response and may lead to improved pharmacological cardioprotective therapies.

Intensive care for human hearts in pluripotent stem cell models

“…In a mechanistically agnostic version of the MAP4K4 cell death studies detailed above, an unbiased chemical biology screen of nearly 50,000 small molecules was performed to identify and validate compounds that protect hPSC-CMs from H 2 O 2 75 . Cardiomyocyte protection was demonstrated using ATP content as the primary end-point and cellular impedance as the secondary readout, a measure of monolayer integrity and contractile function.…”

“…From this screen, in 1536-well format, using a 35% improvement in viability as the criterion, 220 hits were identified of which half were confirmed upon retesting. A novel compound, designated cardioprotectant-312, was found to protect hPSC-CMs from the oxidative stress of H 2 O 2 , triggering upregulation of the essential endogenous anti-oxidant, heme oxygenase-1 75 . Of note, no protection was seen in rat H9c2 cells, embryonic heart-derived myoblasts that are commonly used in toxicology research; conversely, none of the authors' earlier lead compounds identified in H9c2 cells 76 was protective in human cardiomyocytes.…”

Therapeutic Potential of Pluripotent Stem Cells for Cardiac Repair after Myocardial Infarction

“…57,58) 5.1.3. Ischemia Zhang et al 59) revealed that ischemia was one of the main contributors to cell death after transplantation. They transplanted cardiomyocytes into vascularized 2-week-old cardiac granulation tissue or into a normal myocardium.…”

Beyond Family: Modeling Non-hereditary Heart Diseases With Human Pluripotent Stem Cell-Derived Cardiomyocytes

“…Nearly two decades since their first description (Kehat et al, 2001), hPSC-CMs are beginning to fulfill their potential as a reductionist model of the human cardiac muscle. Thanks to constant improvements in differentiation protocols (Mummery et al, 2003;Laflamme et al, 2007;Yang et al, 2008;Kattman et al, 2011;Lian et al, 2012;Burridge et al, 2014) and increasing understanding of their in vitro cardiac phenotype, hPSC-CMs are now an integral part of proposed high-throughput drug screening (Kirby et al, 2018;Fiedler et al, 2019) and drug risk-assessment platforms (Yang and Papoian, 2018;Lu H.R. et al, 2019;Li et al, 2020).…”