Browsing by Author "Alexandre, Bruno M."
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- Evening and morning alterations in Obstructive Sleep Apnea red blood cell proteomePublication . Feliciano, Amélia; Vaz, Fátima; Valentim-Coelho, Cristina; Torres, Vukosava M.; Silva, Rita; Prosinecki, Vesna; Alexandre, Bruno M.; Almeida, Andreia; Almeida-Marques, Catarina; Carvalho, Ana S.; Matthiesen, Rune; Malhotra, Atul; Pinto, Paula; Bárbara, Cristina; Penque, DeborahThis article presents proteomics data referenced in [1] Using proteomics-based evaluation of red blood cells (RBCs), we have identified differentially abundant proteins associated with Obstructive Sleep Apnea Syndrome (OSA). RBCs were collected from peripheral blood of patients with moderate/severe OSA or snoring at pre- (evening) and post-night (morning) polysomnography, so that proteome variations between these time points could be assessed. RBC cytoplasmic fraction depleted of hemoglobin, using Hemovoid(™) system, were analyzed by two-dimensional fluorescence difference gel electrophoresis (2D-DIGE), the 2D image software-based analyzed and relevant differentially abundant proteins identified by mass spectrometry (MS). MS identified 31 protein spots differentially abundant corresponding to 21 unique proteins possibly due to the existence of post-translational modification regulations. Functional analysis by bioinformatics tools indicated that most proteins are associated with catalytic, oxidoreductase, peroxidase, hydrolase, ATPase and anti-oxidant activity. At morning a larger numbers of differential proteins including response to chemical stimulus, oxidation reduction, regulation of catalytic activity and response to stress were observed in OSA. The data might support further research in OSA biomarker discovery and validation.
- Evening and morning peroxiredoxin-2 redox/oligomeric state changes in obstructive sleep apnea red blood cells: Correlation with polysomnographic and metabolic parametersPublication . Feliciano, Amélia; Vaz, Fátima; Torres, Vukosava M.; Valentim-Coelho, Cristina; Silva, Rita; Prosinecki, Vesna; Alexandre, Bruno M.; Carvalho, Ana S.; Matthiesen, Rune; Malhotra, Atul; Pinto, Paula; Bárbara, Cristina; Penque, DeborahWe have examined the effects of Obstructive Sleep Apnea (OSA) on red blood cell (RBC) proteome variation at evening/morning day time to uncover new insights into OSA-induced RBC dysfunction that may lead to OSA manifestations. Dysregulated proteins mainly fall in the group of catalytic enzymes, stress response and redox regulators such as peroxiredoxin 2 (PRDX2). Validation assays confirmed that at morning the monomeric/dimeric forms of PRDX2 were more overoxidized in OSA RBC compared to evening samples. Six month of positive airway pressure (PAP) treatment decreased this overoxidation and generated multimeric overoxidized forms associated with chaperone/transduction signaling activity of PRDX2. Morning levels of overoxidized PRDX2 correlated with polysomnographic (PSG)-arousal index and metabolic parameters whereas the evening level of disulfide-linked dimer (associated with peroxidase activity of PRDX2) correlated with PSG parameters. After treatment, morning overoxidized multimer of PRDX2 negatively correlated with fasting glucose and dopamine levels. Overall, these data point toward severe oxidative stress and altered antioxidant homeostasis in OSA RBC occurring mainly at morning time but with consequences till evening. The beneficial effect of PAP involves modulation of the redox/oligomeric state of PRDX2, whose mechanism and associated chaperone/transduction signaling functions deserves further investigation. RBC PRDX2 is a promising candidate biomarker for OSA severity and treatment monitoring, warranting further investigation and validation.
- Facing challenges in Proteomics today and in the coming decade: Report of Roundtable Discussions at the 4th EuPA Scientific Meeting, Portugal, Estoril 2010Publication . Cox, Jurgen; Heeren, Ron M.A.; James, Peter; Jorrin-Novo, Jesús V.; Kolker, Eugene; Levander, Fredrik; Morrice, Nicholas; Picotti, Paola; Righetti, Pier Giorgio; Sánchez, Jean-Charles; Turckl, Christoph W.; Zubarev, Roman; Alexandre, Bruno M.; Corrales, Fernando J; Marko-Varga, György; O'Donovan, Sinead; O'Neil, Serena; Prechl, Jozsef; Tânia, Simões; Weckwerth, Wolfram; Deborah, PenqueRoundtable Discussion sessions were conceived for the first time at the 4th Edition of the EuPA Annual Scientific Meeting that took place in Estoril, Portugal, from the 23rd to 27th of October, 2010. Under the theme “2010: a proteomics odyssey towards the next decades”, young and senior scientists had the opportunity to discuss particular issues of different proteomic areas s distributed by eleven luncheon roundtables moderated by recognized experts in the field. During two hours, the roundtable discussions proceeded in a friendly environment, in which the participants (about 8–10 per roundtable) were encouraged to ask questions and express their opinions without restraint (Fig. 1). The topics covered a range of recurring issues such as the capabilities and limitations of several proteomic methodologies and suggestions on how researchers may better overcome them. The major goal devised by roundtable leaders was to provide independent advice, describe limitations, give practical tips, help set realistic expectations and answer questions from the participants. Participants were also encouraged to be ambitious in generating new solutions or strategies for the future.
- Proteomic mining of the red blood cell: focus on the membrane proteomePublication . Alexandre, Bruno M.