Thrombopoietin (TPO) regulates HIF-1alpha levels through generation of mitochondrial reactive oxygen species

Int J Hematol. 2008 Jul;88(1):43-51. doi: 10.1007/s12185-008-0091-6. Epub 2008 May 14.

Abstract

Hypoxia inducible factor (HIF)-1 is a master transcriptional regulator mediating the cellular adaptation to hypoxia. In addition, HIF-1 is also vital for the development of hematopoietic stem cells (HSCs). In a previous study we found that thrombopoietin (TPO), an important and non-redundant cytokine for HSC maintenance and expansion, induces HIF-1alpha expression in HSCs by enhancing the stability of HIF-1alpha under normoxic conditions. However, the molecular mechanisms of these effects are not yet fully understood. In this study, we explored the mechanisms and found that TPO-induced mitochondrial reactive oxygen species (ROS) played a crucial role in stabilization of HIF-1. Both ROS scavengers and inhibitors of mitochondrial electron transport completely blocked HIF-1alpha induction by TPO in UT-7/TPO cells and in primary immature mouse bone marrow cells. We also found that TPO-induced HIF-1alpha induction was tightly coupled with glucose metabolism. Inhibition of glucose transporter or glycolytic enzyme blocked HIF-1alpha elevation of TPO. These results indicate that TPO induces HIF-1alpha expression in a manner very similar to that of hypoxia.

Publication types

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

MeSH terms

  • Animals
  • Cell Hypoxia / drug effects
  • Cell Hypoxia / physiology
  • Cell Line
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism*
  • Mice
  • Mitochondria / metabolism*
  • Protein Stability / drug effects
  • Reactive Oxygen Species / metabolism*
  • Thrombopoietin / metabolism
  • Thrombopoietin / pharmacology*

Substances

  • HIF1A protein, human
  • Hif1a protein, mouse
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Reactive Oxygen Species
  • Thrombopoietin