Topological organization of NADPH-oxidase in haematopoietic stem cell membrane: preliminary study by fluorescence near-field optical microscopy

• Published in: Journal of microscopy (Oxford) Vol. 229; no. 3; pp. 517 - 524
• Main Authors: FRASSANITO, M.C, PICCOLI, C, CAPOZZI, V, BOFFOLI, D, TABILIO, A, CAPITANIO, N
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.03.2008
• Subjects: Cell Membrane - enzymology; Cell Membrane - ultrastructure; Hematopoietic Stem Cells - cytology; Hematopoietic Stem Cells - enzymology; Hematopoietic Stem Cells - ultrastructure; Hematopoietic stemcells; Humans; Immunohistochemistry; membrane proteins; Microscopy, Confocal; Microscopy, Fluorescence; Microscopy, Scanning Probe; NADPH oxidase; NADPH Oxidases - analysis; NADPH Oxidases - chemistry; SNOM
• ISSN: 0022-2720; 1365-2818
• DOI: 10.1111/j.1365-2818.2008.01937.x

The aim of this study was to characterize the local distribution and organization of the plasma membrane NADPH-oxidase (NOX) in human haematopoietic stem cell (HSC) by means of the fluorescence scanning near-field optical microscopy approach. The presence of NOX in haematopoietic stem cells is thought to have a functional role as O₂ sensor and/or as low-level reactive oxygen species (ROS) producer to be used as redox messenger for controlling cell growth and differentiation. Given the harmful potential of ROS, a fine-tuning of NOX activity is needed. The high resolution imaging of haematopoietic stem cell membrane obtained in this study combined with the immunodetection of NOX indicates for this the occurrence of a cluster-organized structure. These membrane 'rafts'-like micro-compartments may constitute localized protein aggregates whereby the assembly/activation of the NOX components are functionally integrated with upstream factors constituting signal-transduction platforms.