Hematopoietic stem/progenitor cells express myoglobin and neuroglobin: Adaptation to hypoxia or prevention from oxidative stress?

Abstract

Oxidative metabolism and redox signaling prove to play a decisional role in controlling adult hematopoietic stem/progenitor cells (HSPCs) biology. However, HSPCs reside in a hypoxic bone marrow microenvironment raising the question of how oxygen metabolism might be ensued. In this study, we provide for the first time novel functional and molecular evidences that human HSPCs express myoglobin (Mb) at level comparable with that of a muscle-derived cell line. Optical spectroscopy and oxymetry enabled to estimate an O2-sensitive heme-containing protein content of approximately 180 ng globin per 10 6 HSPC and a P50 of approximately 3 μM O2. Noticeably, expression of Mb mainly occurs through a HIF-1-induced alternative transcript (Mb-V/Mb-N-‰=-‰35-‰±-‰15, p