c-kit+ Precursors Support Postinfarction Myogenesis in the Neonatal, but Not Adult, Heart

Proc Natl Acad Sci U S A. 2012 Aug 14;109(33):13380-5. doi: 10.1073/pnas.1208114109. Epub 2012 Jul 30.

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / metabolism
  • Aging / pathology*
  • Animals
  • Animals, Newborn
  • Cell Lineage
  • Endothelial Cells / metabolism
  • Endothelial Cells / pathology
  • Green Fluorescent Proteins / metabolism
  • Mice
  • Muscle Development*
  • Myocardial Infarction / metabolism
  • Myocardial Infarction / pathology*
  • Proto-Oncogene Proteins c-kit / metabolism*
  • Regeneration
  • Stem Cells / cytology*
  • Stem Cells / metabolism

Substances

  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • Proto-Oncogene Proteins c-kit