title: Impaired expression of DICER, DROSHA, SBDS and some microRNAs in mesenchymal stromal cells from myelodysplastic syndrome patients.
abstract: Background Recent findings suggest that a specific deletion of Dicer1 in mesenchymal stromal cell-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.
  
  
  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.
authors.affiliation: Department of Hematology, University Hospital of Salamanca, Salamanca, Spain. cmsantamaria@usal.es
authors.forename: Carlos
authors.initials: C
authors.lastname: Santamaría
authors.forename: Sandra
authors.initials: S
authors.lastname: Muntión
authors.forename: Beatriz
authors.initials: B
authors.lastname: Rosón
authors.forename: Belén
authors.initials: B
authors.lastname: Blanco
authors.forename: Olga
authors.initials: O
authors.lastname: López-Villar
authors.forename: Soraya
authors.initials: S
authors.lastname: Carrancio
authors.forename: Fermín M
authors.initials: FM
authors.lastname: Sánchez-Guijo
authors.forename: María
authors.initials: M
authors.lastname: Díez-Campelo
authors.forename: Stela
authors.initials: S
authors.lastname: Alvarez-Fernández
authors.forename: María E
authors.initials: ME
authors.lastname: Sarasquete
authors.forename: Javier
authors.initials: J
authors.lastname: de las Rivas
authors.forename: Marcos
authors.initials: M
authors.lastname: González
authors.forename: Jesús F
authors.initials: JF
authors.lastname: San Miguel
authors.forename: María Consuelo
authors.initials: MC
authors.lastname: Del Cañizo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D053487:DEAD-box RNA Helicases / Q000235:genetics*; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000235:genetics* / Q000378:metabolism; D011506:Proteins / Q000235:genetics*; D043244:Ribonuclease III / Q000235:genetics*
chemical_list: D035683:MicroRNAs; D011506:Proteins; C470521:SBDS protein, human; C408087:DICER1 protein, human; C517918:DROSHA protein, human; D043244:Ribonuclease III; D053487:DEAD-box RNA Helicases