title: Apoptosis-associated microRNAs are modulated in mouse, rat and human neural differentiation.
abstract: BACKGROUND
  MicroRNAs (miRs or miRNAs) regulate several biological processes in the cell. However, evidence for miRNAs that control the differentiation program of specific neural cell types has been elusive. Recently, we have shown that apoptosis-associated factors, such as p53 and caspases participate in the differentiation process of mouse neural stem (NS) cells. To identify apoptosis-associated miRNAs that might play a role in neuronal development, we performed global miRNA expression profiling experiments in NS cells. Next, we characterized the expression of proapoptotic miRNAs, including miR-16, let-7a and miR-34a in distinct models of neural differentiation, including mouse embryonic stem cells, PC12 and NT2N cells. In addition, the expression of antiapoptotic miR-19a and 20a was also evaluated.
  
  
  RESULTS
  The expression of miR-16, let-7a and miR-34a was consistently upregulated in neural differentiation models. In contrast, expression of miR-19a and miR-20a was downregulated in mouse NS cell differentiation. Importantly, differential expression of specific apoptosis-related miRNAs was not associated with increased cell death. Overexpression of miR-34a increased the proportion of postmitotic neurons of mouse NS cells.
  
  
  CONCLUSIONS
  In conclusion, the identification of miR-16, let-7a and miR-34a, whose expression patterns are conserved in mouse, rat and human neural differentiation, implicates these specific miRNAs in mammalian neuronal development. The results provide new insights into the regulation of neuronal differentiation by apoptosis-associated miRNAs.
authors.affiliation: Research Institute for Medicines and Pharmaceutical Sciences, Faculty of Pharmacy, University of Lisbon, Lisbon 1649-003, Portugal.
authors.forename: Márcia M
authors.initials: MM
authors.lastname: Aranha
authors.forename: Daniela M
authors.initials: DM
authors.lastname: Santos
authors.forename: Joana M
authors.initials: JM
authors.lastname: Xavier
authors.forename: Walter C
authors.initials: WC
authors.lastname: Low
authors.forename: Clifford J
authors.initials: CJ
authors.lastname: Steer
authors.forename: Susana
authors.initials: S
authors.lastname: Solá
authors.forename: Cecília M P
authors.initials: CM
authors.lastname: Rodrigues
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics*; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics*; D002460:Cell Line; D016000:Cluster Analysis; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008938:Mitosis / Q000187:drug effects / Q000235:genetics; D055495:Neurogenesis / Q000187:drug effects / Q000235:genetics; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013655:Taurochenodeoxycholic Acid / Q000494:pharmacology
chemical_list: D035683:MicroRNAs; D013655:Taurochenodeoxycholic Acid; C031655:ursodoxicoltaurine