title: c-kit+ precursors support postinfarction myogenesis in the neonatal, but not adult, heart.
abstract: We examined the myogenic response to infarction in neonatal and adult mice to determine the role of c-kit(+) cardiovascular precursor cells (CPC) that are known to be present in early heart development. Infarction of postnatal day 1-3 c-kit(BAC)-EGFP mouse hearts induced the localized expansion of (c-kit)EGFP(+) cells within the infarct, expression of the c-kit and Nkx2.5 mRNA, myogenesis, and partial regeneration of the infarction, with (c-kit)EGFP(+) cells adopting myogenic and vascular fates. Conversely, infarction of adult mice resulted in a modest induction of (c-kit)EGFP(+) cells within the infarct, which did not express Nkx2.5 or undergo myogenic differentiation, but adopted a vascular fate within the infarction, indicating a lack of authentic CPC. Explantation of infarcted neonatal and adult heart tissue to scid mice, and adoptive transfer of labeled bone marrow, confirmed the cardiac source of myogenic (neonate) and angiogenic (neonate and adult) cells. FACS-purified (c-kit)EGFP(+)/(αMHC)mCherry(-) (noncardiac) cells from microdissected infarcts within 6 h of infarction underwent cardiac differentiation, forming spontaneously beating myocytes in vitro; cre/LoxP fate mapping identified a noncardiac population of (c-kit)EGFP(+) myocytes within infarctions, indicating that the induction of undifferentiated precursors contributes to localized myogenesis. Thus, adult postinfarct myogenic failure is likely not due to a context-dependent restriction of precursor differentiation, and c-kit induction following injury of the adult heart does not define precursor status.
authors: Department of Biomedical Science, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
authors: Sophy A
authors: SA
authors: Jesty
authors: Michele A
authors: MA
authors: Steffey
authors: Frank K
authors: FK
authors: Lee
authors: Martin
authors: M
authors: Breitbach
authors: Michael
authors: M
authors: Hesse
authors: Shaun
authors: S
authors: Reining
authors: Jane C
authors: JC
authors: Lee
authors: Robert M
authors: RM
authors: Doran
authors: Alexander Yu
authors: AY
authors: Nikitin
authors: Bernd K
authors: BK
authors: Fleischmann
authors: Michael I
authors: MI
authors: Kotlikoff
mesh_terms: D000375:Aging / Q000378:metabolism / Q000473:pathology*; D000818:Animals; D000831:Animals, Newborn; D019070:Cell Lineage; D042783:Endothelial Cells / Q000378:metabolism / Q000473:pathology; D049452:Green Fluorescent Proteins / Q000378:metabolism; D051379:Mice; D024510:Muscle Development; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology*; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism*; D012038:Regeneration; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism
chemical_list: C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D019009:Proto-Oncogene Proteins c-kit