Browsing by Author "Barbara, Cristina"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Diabetes mellitus tipo 2 (DMT2) associada a Sindrome de Apneia Obstrutiva do Sono (SAOS): um estudo proteómicoPublication . Vaz, Fátima; Valentim-Coelho, Cristina; Neves, Sofia; Penque, Deborah; Barbara, CristinaIntrodução: A prevalência da SAOS é elevada em doentes com DMT2. O não tratamento da SAOS pode levar ao agravamento ou desenvolvimento da DMT2. Temos vindo a demonstrar que a SAOS altera o proteoma do glóbulo vermelho (GV). A SAOS aumenta a overoxidação da peroxirredoxina 2 (PRDX2) (enzima antioxidante), o que pode levar à desregulação da homeostasia do GV e ao desenvolvimento de doenças metabólicas. Após tratamento com ventilação não invasiva (PAP), esta overoxidação diminuiu seguida de um aumento de PRDX2 decamérica overoxidada com funções chaperone na proteção celular (Feliciano et al. 2017). No presente estudo, fomos investigar o estado redox/oligomérico da PRDX2 em doentes DMT2 com SAOS, antes/após PAP, para melhor compreender a interligação entre estas patologias. Material e métodos: Amostras de GVs de controles (n=22 sendo 3 DMT2) e doentes SAOS antes/após 6 meses de tratamento com PAP (n=29 sendo 8 DMT2) foram analisadas por western-blot não reduzido, com anticorpo para a PRDX2 e PRDXSO2/3 (overoxidada). Os grupos foram comparados estatisticamente e correlacionados com dados clínicos e bioquímicos. Resultados: Nos GVs de doentes DMT2/SAOS, o nível de monómeros da PRDX2 mostrou-se aumentado e diminuía após PAP. Contudo, o nível destes monómeros PRDXSO2/3 estava diminuído e não se alterou com o tratamento. Após PAP, o nível de decâmeros PRDX2SO2/3 foi também menor nestes doentes. Os níveis de monómeros PRDX2 e PRDX2SO2/3 correlacionaram-se negativamente com os níveis de insulina/triglicéridos e HbA1C, respetivamente. Após PAP, os níveis de decâmeros PRDX2SO2/3 correlacionou-se positivamente com os níveis de adrenalina. Conclusões: O estado redox/oligomérico da PRDX2 do GV é diferencialmente modulado nos doentes DTM2/SAOS em comparação com doentes SAOS. Decâmeros PRDXSO2/3 induzidos pelo tratamento e associadas à função protetora “chaperone” estão diminuídos em doentes DMT2/SAOS. O impacto clínico destas descobertas, necessita de mais investigação e validação.
- Effects of positive airway pressure therapy on red blood cells in patients with obstructive sleep apneaPublication . Coelho-Valentim, Cristina; Vaz, Fátima; Barbara, Cristina; Penque, DeborahIntroduction: Obstructive Sleep Apnea (OSA) syndrome is characterized by recurrent arousals from sleep and intermittent hypoxemia. We recently demonstrated that OSA can cause alterations in the red blood cells (RBC) proteome that may be associated with OSA outcomes. Here we intend to investigate whether the positive airway pressure (PAP) treatment can revert/modulate these proteome alterations.
- Obstructive sleep apnea associated with Diabetes mellitus Type 2: a proteomic studyPublication . Vaz, Fátima; Valentim-Coelho, Cristina; Neves, Sofia; Feliciano, Amelia; Antunes, Marília; Pinto, Paula; Barbara, Cristina; Penque, DeborahBackground: We previously showed that Obstructive sleep apnea (OSA), a common public health concern causing deleterious cardiometabolic dysfunction, induced proteomic alterations in red blood cells (RBC) such as changes in the redox-oligomeric state of peroxiredoxin 2 (PRDX2)1-2. Herein, we aimed to investigate whether OSA patients with Type 2 Diabetes Mellitus before and after positive airway pressure (PAP) treatment present similar changes in the RBC antioxidant protein PRDX2 to better understand the molecular basic mechanisms associated with OSA and OSA outcomes. Methods: RBC samples from control snorers (n=22 being 3 diabetics) and OSA patients before and after six month of PAP-treatment (n=29 being 8 diabetics) were analysed by non-reducing western blot using antibody against PRDX2 or PRDXSO2/3 to measure the total and overoxidized levels of monomeric/dimeric/multimeric forms of PRDX2. Results: We confirmed previously data by showing that in OSA RBC the overoxidation on the monomeric forms of PRDX2 was higher compared to controls. After PAP treatment, this overoxidation decreased followed by an increase of multimeric-overoxidized forms of PRDX2 described to be associated with chaperone protective function. In contrast, the level of PRDX2 monomers in RBC diabetic OSA, although higher abundant its overoxidation level was much lower than those observed in OSA without comorbidity and did not significant change after treatment. Moreover, the level of PAP-induced PRDX2-overoxidized-multimers was also lower in these diabetic OSA patients. The level of overoxidized monomeric/dimeric forms of PRDX2 correlated negatively with levels of insulin / triglycerides and HbA1C, respectively. After PAP, the level of (overoxidized) PRDX2SO2/3 multimers correlated positively with adrenaline levels. Conclusions: The redox/oligomeric state of RBC PRDX2 that is regulated by overoxidation of the active cysteines was differentially modulated in diabetic OSA patients compared to OSA without this comorbidity. PAP-induced overoxidized oligo forms of PRDX2 that is associated with chaperone protective function showed decreased in OSA patients with diabetes. The clinical impact of these findings needs further investigation and validation.
- Shotgun proteomics of red blood cells from obstructive sleep apnea patients under positive airway pressure (PAP) treatmentPublication . Coelho, Cristina Valentim; Osório, Hugo; Vaz, Fatima; Neves, Sofia; Pinto, Paula; Barbara, Cristina; Penque, DeborahObstructive Sleep Apnea (OSA) syndrome is characterized by recurrent episodes of apneas and hypopneas during sleep, leading to recurrent intermittent hypoxia and sleep fragmentation. No treated OSA can result in metabolic and cardiovascular diseases. By 2D gel-based proteomics approach we have demonstrated that OSA can cause alterations in the red blood cells (RBC) proteome that may be associated with OSA outcomes. OSA induces alterations in the redox/oligomeric states of RBC proteins such as gyceraldehyde-3-phosphate dehydrogenase (GAPDH) and peroxiredoxin-2 (PRDX2) that can be reverted or modulated by PAP treatment. In this study, we applied a shotgun proteomics strategy to further investigate the RBC proteome from patients with OSA before and after PAP treatment to better understand the regulation of RBC homeostasis in the context of OSA and/or under effect of PAP treatment. As a first approach, RBCs samples, corresponding to Snorers patients as control (n=23) and patients with OSA before and after six months of PAP treatment (n=33/condition) were selected from our biobank1. Samples were randomly pooled (n=3 per group/condition) and lysed 1:6 with 5mM sodium phosphate buffer containing 100 mM of N-ethylmaleimide, a reagent that alkylates free sulfhydryl groups, before haemoglobin depletion by using HemovoidTM system. Depleted samples were alkylated, reduced and digested with trypsin and chymotrypsin. The resulting peptides were cleaned with C18 columns and analysed in triplicate by a Nano High Performance Liquid Chromatography (nanoHPLC) on-line coupled to a high-resolution accurate-mass Orbitrap mass spectrometer (Q Exactive, Thermo Scientific) with a nano electrospray ionization source (nanoESI). The acquired mass spectrometry data were analysed by MaxQuant v1.5.8.3 and Perseus v2.0.3.1 software. The preliminary results corroborated our previous findings by showing that proteins associated with stress response and antioxidant regulatory system were the most changed in OSA RBC compared with Snorers ones. The active catalytic cysteine (Cys 51) in the PRDX2 was identified trioxidized –SO3H almost exclusively in OSA RBC before PAP treatment. Further analyses and validation of these data are in progress, which will certainly provide a better understanding of RBC molecular mechanisms and their proteins/PTMs associated with OSA pathology and/or response to PAP therapy.