Pathologic Stimulus Determines Lineage Commitment of Cardiac C-kit ⁺ Cells

Abstract

Background Although cardiac c-kit+ cells are being tested in clinical trials, the circumstances that determine lineage differentiation of c-kit+ cells in vivo are unknown. Recent findings suggest endogenous cardiac c-kit+ cells rarely contribute cardiomyocytes to the adult heart. We assessed whether various pathological stimuli differentially affect the eventual cell fates of c-kit+ cells. Methods We employed single cell sequencing and genetic lineage tracing of c-kit+ cells to determine whether various pathologic stimuli would result in different fates of c-kit+ cells. Results Single cell sequencing of cardiac CD45−c-kit+ cells showed innate heterogeneity, indicative of the existence of vascular and mesenchymal c-kit+ cells in normal hearts. Cardiac pressure overload resulted in a modest increase in c-kit derived cardiomyocytes with significant increases in the numbers of endothelial cells and fibroblasts. Doxorubicin-induced (DOX) acute cardiotoxicity did not increase c-kit derived endothelial cell fates but instead induced cardiomyocyte differentiation. Mechanistically, DOX induced DNA damage in c-kit+ cells resulted in expression of p53. Inhibition of p53 blocked cardiomyocyte differentiation in response to DOX, while the small molecule RITA induced stabilization of p53 was sufficient to increase c-kit derived cardiomyocyte differentiation. Conclusion These results demonstrate that different pathologic stimuli induce different cell fates of c-kit+ cells in vivo. Although the overall rate of cardiomyocyte formation from c-kit+ cells is still below clinically relevant levels, we show that p53 is central to the ability of c-kit+ cells to adopt cardiomyocyte fates, which could lead to the development of strategies to preferentially generate cardiomyocytes from c-kit+ cells.

Pressure overload by suprarenal aortic constriction in mice leads to left ventricular hypertrophy without c-Kit expression in cardiomyocytes

“…Indeed, genetic lineage-tracing models have shown that c-Kit is expressed in a subpopulation of endothelial cells 12 that double after MI 11 and that cardiomyocytes rarely express c-Kit or originate from c-Kit + cells 11 , 13 , 14 . One lineage-tracing study reported a modest increase in c-Kit-expressing cardiomyocytes following TAC-induced PO, although the increase was below clinically-relevant levels 45 . However, genetic lineage-tracing Kit-Cre models that result in haploinsufficiency of the c-Kit gene have been questioned, as reviewed 46 – 49 .…”

Human Wharton’s Jelly-Derived Mesenchymal Stem Cells Minimally Improve the Growth Kinetics and Cardiomyocyte Differentiation of Aged Murine Cardiac c-kit Cells in In Vitro without Rejuvenating Effect

“…Exposing aged animals or cells to young microenvironment has been shown to reverse ageing phenotypes [35,36,37,38,39], but Wharton’s Jelly MSCs did not rejuvenate aCCs in co-culture. This may be attributed to insufficient MSC coculture time to observe an effect in aCCs which were chronically exposed to surrounding ageing stimuli in vivo [40], i.e., the senescence associated secretory phenotype (SASP) [41], a known cell senescent accelerator [42]. Nonetheless, our data shows that MSCs improved aCC migration and proliferation.…”

Targeted expression of cyclin D2 ameliorates late stage anthracycline cardiotoxicity

“…Alternatively, it is possible that there is a labile cardiomyogenic stem cell population, which is progressively eliminated by DOX treatment over time. However, recent results using a lineage trace system demonstrated that DOX treatment actually enhances cardiomyogenic activity in putative c-kit progenitor cells, 30 thus a permanent reduction in transgene-induced cardiomyocyte S-phase activity would not be anticipated (particularly since the MHC-cycD2 transgene would not be expected to be expressed in a progenitor cell which has not yet adopted a cardiac phenotype).…”