Proteomics of red blood cell from patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) is responsible for metabolic/cardiovascular consequences, but its molecular mechanisms are poorly defined. Using 2-D Fluorescence Difference Gel Electrophoresis and mass spectrometry proteomics evaluation of red blood cells (RBC), we plan to identify dysregulated proteins (possible OSA biomarkers). To assess proteome variations, RBC were collected from blood of moderate/severe OSA (n=12) or simple snoring (n=12) at pre- and post- night sleep. RBC samples were randomized pooled to 3 replicates/group of patients/condition. Samples were fractionated into membrane and soluble fractions, being the latter depleted of hemoglobin. Soluble RBC fractions were labeled with GE fluorescente dyes and separated by 2DE. After that the images were acquired in an Imager and analysed by Progenesis SameSpots software. 70 spots were differentially expressed (p‹0.05) between OSA and simple snoring and at pre/post-night sleep were excised from a Coomassie-stained preparative gels and proteins identified by MALDI-TOF/TOF MS. Pathway analysis was carried out by Ingenuity Pathway Analysis. The most significant networks were associated with cellular response to hydrogen peroxide/reactive oxygen species. The complete identification/validation of those proteins will provide better understanding of OSA and translated into diagnosis/prognosis tools. Work supported by Harvard Medical School-Portugal Program (HMSP-ICJ/0022/2011), FCT/Poly-Annual Funding Program and FEDER/Saude XXI Program. 2-DIGE images were captured at Instituto de Tecnologia Quimica/Biologica, Portugal. Work approved by the Ethical Committees of involved institutions and Comissao Nacional de Protecao de Dados.