Profiling proliferative cells and their progeny in damaged murine hearts

The significance of cardiac stem cell (CSC) populations for cardiac regeneration remains disputed. Here, we apply the most direct definition of stem cell function (the ability to replace lost tissue through cell division) to interrogate the existence of CSCs. By single-cell mRNA sequencing and genetic lineage tracing using two Ki67 knockin mouse models, we map all proliferating cells and their progeny in homoeostatic and regenerating murine hearts. Cycling cardiomyocytes were only robustly observed in the early postnatal growth phase, while cycling cells in homoeostatic and damaged adult myocardium represented various noncardiomyocyte cell types. Proliferative postdamage fibroblasts expressing follistatin-like protein 1 (FSTL1) closely resemble neonatal cardiac fibroblasts and form the fibrotic scar. Genetic deletion of Fstl1 in cardiac fibroblasts results in postdamage cardiac rupture. We find no evidence for the existence of a quiescent CSC population, for transdifferentiation of other cell types toward cardiomyocytes, or for proliferation of significant numbers of cardiomyocytes in response to cardiac injury. Overall design: We generated transciptome data from proliferative cardiac cells collected from 3, 7 or 14 days following myocardial infarction (MI) or sham surgery. This series includes single-cell transcriptome data from (Ki67-RFP+) cardiac cells collected from neonatal murine hearts, adult homeostatic murine hearts or adult murine hearts collected 14 days following myocardial infarction (MI), ischemic/perfusion (I/R) or sham surgery.

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Kretzschmar K, Post Y, Bannier-Hélaouët M, Mattiotti A, Drost J, Basak O, Li VSW, van den Born M, Gunst QD, Versteeg D, Kooijman L, van der Elst S, van Es JH, van Rooij E, van den Hoff MJB, Clevers H