Transcriptional and proteomic analyses of redox enviorement in beta-thalassemia trait

Abstract

β-Thalassemia trait (BTT) is a heterogeneous group of genetic defects leading to decreased β -globin production, ineffective erythropoiesis and oxidative stress. Reactive oxygen speciesproduction and oxidative environment have an impact on all blood cell lineages. The aim was toevaluate, at transcriptional and proteomic levels, the pro-oxidative and anti-oxidative status in BTTpatients. A descriptive study was performed with 66 subjects (40 apparently healthy and 26 withBTT). Real-time PCR was used for gene expression analyses of transcription factors forkheadhomeobox typeO (FOXO3a) and nuclear factor erythroid2-related factor-2 (NRF2); antioxidantenzymes: catalase (CAT), peroxiredoxin-2 (PRX-2), superoxide dismutase (SOD); and cytokines TNF-α, IL-6. Quantitative mass spectrometry was performed on cytosol erythrocyte membranesdepleted of hemoglobin. Bioinformatic analysis was performed with Perseus, BlastKoala andProteome Discoverer V1.4 programs.Relative expression of NRF2 was 4.7-fold higher in BTT than in control group, whereas FOXO3aexpression was similar in both. Transcriptional expression of SOD, PRDX2 and proinflammatorycytokines were significantly upregulated in BTT compared to controls (p<0,005). Proteomic studyshowed significant difference in abundances of oxidative stress and inflammation markers such aslipoxygenase15 (ALOX15), poly-C-binding protein 1/2 (PCBP 1/2), P40/P67 subunit of NADPHoxidase and 70 kilodalton heat shock protein (HSP70), tyrosine-protein kinase (SYK) in BTT (p˂0,05). Proteins involved in redox imbalance protection such as glutathione S-transferase kappa1(GSTκ1), isocitrate dehydrogenase 1/2 (IDH1/2) and glucose-6-phosphate dehydrogenase (G6PD)were higher in BTT than in controls (4.2, 4.1 and 2.1 fold respectively). These results showedchanges in the gene expression of some redox regulators together with modifications in theerythrocyte proteome generated by the global redox imbalance underlying in this pathology