Impaired expression of DICER, DROSHA, SBDS and some microRNAs in mesenchymal stromal cells from myelodysplastic syndrome patients

This is an open-access paper.[Background]: Recent findings suggest that a specific deletion of Dicer1 in mesenchymal stromal cells-derived osteoprogenitors triggers several features of myelodysplastic syndrome in a murine model. Our aim was to analyze DICER1 and DROSHA gene and protein expression in mesenchymal stromal cells (the osteoblastic progenitors) obtained from bone marrow of myelodysplastic syndrome patients, in addition to microRNA expression profile and other target genes such as SBDS, a DICER1-related gene that promotes bone marrow dysfunction and myelodysplasia when repressed in a murine model. [Design and Methods]: Mesenchymal stromal cells from 33 bone marrow samples were evaluated. DICER, DROSHA and SBDS gene expression levels were assessed by real-time PCR and protein expression by Western blot. MicroRNA expresion profile was analyzed by commercial low-density arrays and some of these results were confirmed by individual real-time PCR. [Results]: Mesenchymal stromal cells from myelodysplastic syndrome patients showed lower DICER1 (0.65±0.08 vs. 1.91±0.57; P=0.011) and DROSHA (0.62±0.06 vs. 1.38±0.29; P=0.009) gene expression levels, two relevant endonucleases associated to microRNA biogenesis, in comparison to normal myelodysplastic syndrome. These findings were confirmed at protein levels by Western blot. Strikingly, no differences were observed between paired mononuclear cells from myelodysplastic syndrome and controls. In addition, mesenchymal stromal cells from myelodysplastic syndrome patients showed significant lower SBDS (0.63±0.06 vs. 1.15±0.28; P=0.021) gene expression levels than mesenchymal stromal cells from healthy controls. Furthermore, mesenchymal stromal cells from myelodysplastic syndrome patients showed an underlying microRNA repression compared to healthy controls. Real-time PCR approach confirmed that mir-155, miR-181a and miR- 222 were down-expressed in mesenchymal stromal cells from myelodysplastic syndrome patients. [Conclusions]: This is the first description of an impaired microRNA biogenesis in human mesenchymal stromal cells from myelodysplastic syndrome patients, where DICER1 and DROSHA gene and protein downregulation correlated to a gene and microRNA abnormal expression profile, validating the animal model results previously described.Grants from Consejeria de Educacion de la Junta de Castilla y León (HUS03A09) and Instituto de Salud Carlos III (FIS09/01530).Peer reviewe

Orthographic learning in Spanish children: influence of previous semantic and phonological knowledge

This study was funded by Grant PSI2015-64174-P from the Spanish Government and sup-ported by the predoctoral grant BP14-038 from the Foundation for the Promotion of Ap-plied Scientific Research and Technology in Asturias (FICYT