Bone marrow endosteal mesenchymal progenitors depend on HIF factors for maintenance and regulation of hematopoiesis

Stem Cell Reports. 2014 May 15;2(6):794-809. doi: 10.1016/j.stemcr.2014.04.002. eCollection 2014 Jun 3.

Abstract

Maintenance and differentiation of hematopoietic stem cells (HSCs) is regulated through cell-autonomous and non-cell-autonomous mechanisms within specialized bone marrow microenvironments. Recent evidence demonstrates that signaling by HIF-1α contributes to cell-autonomous regulation of HSC maintenance. By investigating the role of HIF factors in bone marrow mesenchymal progenitors, we found that murine endosteal mesenchymal progenitors express high levels of HIF-1α and HIF-2α and proliferate preferentially in hypoxic conditions ex vivo. Inactivation of either HIF-1α or HIF-2α dramatically affects their phenotype, propagation, and differentiation. Also, downregulation of HIF factors provokes an increase in interferon-responsive genes and triggers expansion and differentiation of hematopoietic progenitors by a STAT1-mediated mechanism. Interestingly, in conditions of demand-driven hematopoiesis HIF factors are specifically downregulated in mesenchymal progenitors in vivo. In conclusion, our findings indicate that HIF factors also regulate hematopoiesis non-cell-autonomously by preventing activation of a latent program in mesenchymal progenitors that promotes hematopoiesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / metabolism
  • Bone Marrow Cells / cytology*
  • Cell Differentiation / genetics
  • Cell Differentiation / physiology
  • Hematopoiesis / genetics
  • Hematopoiesis / physiology*
  • Hematopoietic Stem Cells / cytology*
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • Mesenchymal Stem Cells / cytology
  • Mesenchymal Stem Cells / metabolism*
  • Mice
  • Signal Transduction / physiology

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • Hif1a protein, mouse
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • endothelial PAS domain-containing protein 1