D'Aprile 2014 Stem Cells
|D'Aprile A, Scrima R, Quarato G, Tataranni T, Falzetti F, Di Ianni M, Gemei M, Del Vecchio L, Piccoli C, Capitanio N (2014) Hematopoietic stem/progenitor cells express myoglobin and neuroglobin: adaptation to hypoxia or prevention from oxidative stress? Stem Cells 32:1267-77.|
Abstract: Oxidative metabolism and redox signalling 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 ≈ 180 ng globin/106 HSPC and a P50 ≈ 3 μM O2 . Noticeably, expression of Mb mainly occurs through a HIF-1-induced alternative transcript (Mb-V/Mb-N =35 ±15, P<0.01). A search for other Mb-related globins unveiled significant expression of neuroglobin (Ngb) but not of cytoglobin. Confocal microscopy immune-detection of Mb in HSPCs strikingly revealed nuclear localization in cell subsets expressing high level of CD34 (nuclear/cytoplasmic Mb ratios 1.40 ±0.02 vs. 0.85 ±0.05, P< 0.01) whereas Ngb was homogeneously distributed in all the HSPC population. Dual-color fluorescence flow cytometry indicated that while the Mb content was homogeneously distributed in all the HSPC subsets that of Ngb was two-fold higher in more immature HSPC. Moreover, we show that HSPCs exhibit a hypoxic nitrite reductase activity releasing NO consistent with described non-canonical functions of globins. Our finding extends the notion that Mb and Ngb can be expressed in non-muscle and non-neural contexts respectively and is suggestive of a differential role of Mb in HSPC in controlling oxidative metabolism at different stages of commitment.
• O2k-Network Lab: IT Foggia Capitanio N
Labels: MiParea: Respiration
Organism: Human Tissue;cell: Stem cells Preparation: Intact cells
Coupling state: ROUTINE