CXCR4+/FLK-1+ biomarkers select a cardiopoietic lineage from embryonic stem cells

Stem Cells. 2008 Jun;26(6):1464-73. doi: 10.1634/stemcells.2007-0808. Epub 2008 Mar 27.

Abstract

Pluripotent stem cells demonstrate an inherent propensity for unrestricted multi-lineage differentiation. Translation into regenerative applications requires identification and isolation of tissue-specified progenitor cells. From a comprehensive pool of 11,272 quality-filtered genes, profiling embryonic stem cells at discrete stages of cardiopoiesis revealed 736 transcripts encoding membrane-associated proteins, where 306 were specifically upregulated with cardiogenic differentiation. Bioinformatic dissection of exposed surface biomarkers prioritized the chemokine receptor cluster as the most significantly over-represented gene receptor family during pre cardiac induction, with CXCR4 uniquely associated with mesendoderm formation. CXCR4(+) progenitors were sorted from the embryonic stem cell pool into mesoderm-restricted progeny according to co-expression with the early mesoderm marker Flk-1. In contrast to CXCR4(-)/Flk-1(-) cells, the CXCR4(+)/Flk-1(+) subpopulation demonstrated overexpressed cardiac lineage transcription factors (Mef2C, Myocardin, Nkx2.5), whereas pluripotent genes (Oct4, Fgf4, Sox2) as well as neuroectoderm (Sox1) and endoderm alpha-fetoprotein markers were all depleted. In fact, the CXCR4(+)/Flk-1(+) biomarker combination identified embryonic stem cell progeny significantly enriched with Mesp-1, GATA-4, and Tbx5, indicative of pre cardiac mesoderm and the primary heart field. Although the CXCR4(+)/Flk-1(+) transcriptome shared 97% identity with the CXCR4(-)/Flk-1(-) counterpart, the 818 divergent gene set represented predominantly cardiovascular developmental functions and formed a primitive cardiac network. Differentiation of CXCR4(+)/Flk-1(+) progenitors yielded nuclear translocation of myocardial transcription factors and robust sarcomerogenesis with nascent cardiac tissue demonstrating beating activity and calcium transients. Thus, the CXCR4/Flk-1 biomarker pair predicts the emergence of cardiogenic specification within a pluripotent stem cell pool, enabling targeted selection of cardiopoietic lineage. Disclosure of potential conflicts of interest is found at the end of this article.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers / analysis
  • Calcium / physiology
  • Cell Differentiation
  • DNA, Complementary / genetics
  • Embryonic Stem Cells / cytology*
  • Embryonic Stem Cells / physiology
  • Endoderm / cytology
  • Endoderm / physiology
  • Gene Expression Profiling
  • Mesoderm / cytology
  • Mesoderm / physiology
  • Mice
  • Myocytes, Cardiac / cytology
  • Myocytes, Cardiac / physiology*
  • RNA / genetics
  • RNA / isolation & purification
  • Receptors, CXCR4 / genetics*
  • Vascular Endothelial Growth Factor Receptor-2 / genetics*

Substances

  • Biomarkers
  • CXCR4 protein, mouse
  • DNA, Complementary
  • Receptors, CXCR4
  • RNA
  • Vascular Endothelial Growth Factor Receptor-2
  • Calcium