Sublethal Caspase Activation Promotes Generation of Cardiomyocytes from Embryonic Stem Cells

Abstract

Generation of new cardiomyocytes is critical for cardiac repair following myocardial injury, but which kind of stimuli is most important for cardiomyocyte regeneration is still unclear. Here we explore if apoptotic stimuli, manifested through caspase activation, influences cardiac progenitor up-regulation and cardiomyocyte differentiation. Using mouse embryonic stem cells as a cellular model, we show that sublethal activation of caspases increases the yield of cardiomyocytes while concurrently promoting the proliferation and differentiation of c-Kit+/α-actininlow cardiac progenitor cells. A broad-spectrum caspase inhibitor blocked these effects. In addition, the caspase inhibitor reversed the mRNA expression of genes expressed in cardiomyocytes and their precursors. Our study demonstrates that sublethal caspase-activation has an important role in cardiomyocyte differentiation and may have significant implications for promoting cardiac regeneration after myocardial injury involving exogenous or endogenous cell sources.

Effective Hypothermic Storage of Human Pluripotent Stem Cell-Derived Cardiomyocytes Compatible With Global Distribution of Cells for Clinical Applications and Toxicology Testing

“…The expression of typical CM genes (including transcription factors, specific structural genes, and ionic channels) were revealed to be significantly higher in stored hiPSC‐CMs than in the control, suggesting that the hypothermia state may enhance CM enrichment/maturation processes. A recent study reported that apoptotic stimuli—more specifically, a sublethal caspase‐activation—up‐regulates cardiac progenitor and CM differentiation, increasing the final yield of CMs [56]. As shown in our study and in others [16, 37, 57], the hypothermic state promotes caspase activation; consequently, we could also speculate about an interference of cold preservation in cardiogenic pathways.…”

Non-apoptotic Caspase regulation of stem cell properties

“…Recent studies suggest that sublethal caspase activation in murine-ESCs promotes the proliferation and differentiation of c-Kit + /α-actinin low cardiac progenitor cells [37] . Reciprocally, caspase inhibition dramatically reduces the amount of differentiated cardiomyocytes [37] .…”

Cryopreservation of human pluripotent stem cell-derived cardiomyocytes is not detrimental to their molecular and functional properties

“…A similar observation was evident in hPSC-CMs stored under hypothermic conditions (+4°C), with the expression of several cardiomyocyte-specific genes including MLC2V significantly upregulated (Correia et al, 2016). The exact mechanism by which cold preservation could induce hPSC-CM maturation is unclear but hypothermic storage does increase caspase activity which has been demonstrated to promote the differentiation of mouse embryonic stem cell (ESC)-derived cardiac progenitors (Bulatovic et al, 2015). Alternatively, exposure of the hPSC-CMs to DMSO may also contribute to the enrichment in ventricular cardiomyocytes.…”