Proteome Profiling in Obstructive Sleep Apnea Severity and Treatment Response Towards Early Diagnosis and Prognosis Prediction

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Proteome profiling in obstructive sleep apnea severity and treatment response towards early diagnosis and prognosis prediction

Publication . Valentim-Coelho, Cristina; Penque, Deborah; Dias, Deodália; Antunes, Marília Cristina de Sousa

Obstructive Sleep Apnea (OSA) is characterized by recurrent episodes of apneas/hypopneas during sleep, leading to intermittent hypoxia and sleep fragmentation that can result in cardiometabolic diseases. A Proteomic approach was applied to investigate RBC homeostasis regulation in the context of OSA, before (t0) and after six months (t6) of PAP treatment. This work aims the discovery of candidate blood biomarkers for the diagnosis/prognosis of OSA and/or the monitoring/effectiveness of therapy. RBC samples were analysed through 2D-DIGE and the differentially expressed protein spots identified by MALDI-TOF/TOF MS. Three GAPDH-proteoforms were detected as decreased in OSA RBCs when compared to control ones that after PAP increased. An acidic PRDX2-proteoform, reported as hyperoxidized, showed changes between groups. By Western-Blot the results indicated that the redox-oligomeric state of GAPDH and PRDX2 may be compromising the homeostasis of OSA RBCs. The GAPDH monomer combined with BMI and the PRDX2 S-S dimer combined with the HOMA-IR showed to be promising biomarkers for predicting OSA and the severity of OSA, respectively. A Shotgun LC-MS/MS study was also performed on RBCs from patients with Mild and Severe OSA, before and after six months of PAP, using Snorers as controls. Dysregulation in Glycolysis and Pentose Phosphate pathways was observed in Severe OSA RBCs. Mild OSA showed a decrease in the Rapoport-Luebering shunt, which is associated with increased affinity for Hb-O2. Proteins of the immunoproteasome were upregulated in Severe OSA RBCs maybe to respond to severe oxidative stress. In Mild OSA RBCs, proteins related to the ubiquitination/neddylation-(Ub/Ned)-dependent proteasome system were up-regulated. After PAP, proteins of Glycolysis and Ub/Ned-dependent proteasome system showed reactivated in Severe OSA RBC. In Mild-OSA RBC, PAP induced upregulation of immunoproteasome proteins, suggesting that this treatment may increase oxidative stress in these patients. Once validated these proteins maybe candidate biomarkers for OSA.

2025-03-28Doctoral thesis

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Redox–oligomeric state of Peroxiredoxin-2 and Glyceraldehyde-3-phosphate dehydrogenase in obstructive sleep apnea red blood cells under positive airway pressure therapy

Publication . Valentim Coelho, Cristina; Vaz, Fátima; Antunes, Marilia; Neves, Sofia; Martins, Inês L.; Osório, Hugo; Feliciano, Amélia; Pinto, Paula; Bárbara, Cristina; Penque, Deborah

In this study, we examined the effect of six months of positive airway pressure (PAP) therapy on Obstructive Sleep Apnea (OSA) red blood cell (RBC) proteome by two dimensional difference gel electrophoresis (2D-DIGE) - based proteomics followed by Western blotting (WB) validation. The discovered dysregulated proteins/proteoforms are associated with cell death, H2O2 catabolic/metabolic process, stress response, and protein oligomerization. Validation by nonreducing WB was performed for peroxiredoxin-2 (PRDX2) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by using antibodies against the sulfinylated/sulfonylated cysteine of these proteins to better evaluate their redox-oligomeric states under OSA and/or in response to PAP therapy. The results indicated that the redox-oligomeric state of GAPDH and PRDX2 involving overoxidation by sulfinic/sulfonic acids were differentially modulated in OSA RBC, which might be compromising RBC homeostasis. PAP therapy by restoring this modulation induced a higher oligomerization of overoxidized GAPDH and PRDX2 in some patients that could be associated with eryptosis and the chaperone "gain" of function, respectively. This varied response following PAP may result from the complex interplay between OSA and OSA metabolic comorbidity. Hence, information on the redox status of PRDX2 and GAPDH in RBC will help to better recognize OSA subtypes and predict the therapeutic response in these patients. GAPDH monomer combined with body mass index (BMI) and PRDX2 S-S dimer combined with homeostatic model assessment for insulin resistance (HOMA-IR) showed to be very promising biomarkers to predict OSA and OSA severity, respectively.

2020Journal article

Open access