InflammamiRs profile in myelodysplastic syndrome patients

Etiological factors involved in myelodysplastic syndrome (MDS) include immunologic, oxidative stress, and inflammatory factors, among others, and these are targets for microRNAs (miRNs). Here, we evaluated whether some miRNs may affect the tumor development comparing untreated and 5-azacitidine (5-AZA) MDS-treated patients. Peripheral blood samples were collected from 20 controls and 24 MDS patients, and selected miRNs related to redox balance and inflammation, including miR-18a, miR-21, miR-34a and miR-146a, were isolated and measured by quantitative real-time polymerase chain reaction (qRTPCR). A differential expression profile of miRNs was detected in untreated MDS patients and 5-AZA group. MiR-18a, miR-21, miR-34a and miR-146a were significantly overexpressed in untreated MDS, compared to controls. However, we did not observe any miRNs profile alteration during the progression of the disease. On the other hand, 5-AZA treatment tends to restore miRNs expression levels. Relating to prognostic risk factors, high risk MDS groups (high IPSS-R, high cytogenetic risk, high molecular risk (HMR) mutations tended to be related with higher expression levels of miR-18a and miR-34a. Higher miRNs expression is correlated with lower glutathione peroxidase activity, while they are related with a higher profile of pro-inflammatory cytokines (IL-2, IL-6, IL-8, TNF-α). Although our study was limited by the low number of MDS patients included, we identified miRNs deregulation involved in the MDS development, that could regulate redox sensors and inflammatory responses. Finally, 5-AZA treatment is related with lower miRNs expression levels in MDS patients.