Regulation of adult mouse SVZ-derived neural stem cells properties by the transcriptional factor REST

Neural stem cell (NSC) properties are finely regulated by changes in their transcriptional program. A compelling factor involved in neuronal differentiation is the RE1 silencing transcription factor (REST). REST is a multifunction transcriptional regulator that represses or silences many genes in both neural and non-neural cells by largely unclear mechanisms that seem to depend upon developmental stage and cell type (Johnson R et al, 2008). REST is expressed at high levels in embryonic stem (ES) cells and declines during ES conversion into the neural cell lineage and fetal NSC differentiation into neurons. Recent studies highlight the crucial role of REST in regulating adult neurogenesis (Gao Z et al, 2011). We have explored how REST regulates the properties of NSCs derived from the mouse adult subventricular zone. We demonstrated that REST is expressed in different clonally derived aNSC lines and that it binds to several well-known target genes, repressing their expression. RNA interference-mediated knockdown of REST in a transiently or stable transfected clonal cell line (aNSC1) promoted cell differentiation into neurons and glia, despite the presence of growth factors in the culture medium. Interestingly REST silencing did not modify the neurogenic and gliogenic potential of aNSC1 induced to differentiate by growth factors withdrawal. These data suggest that REST knock down is sufficient to induce NSC differentiation but it does not affect their lineage-specific differentiation program. Consistently, knockdown of REST in primary neurospheres impaired their growth and clonogenic potential, as evidenced in proliferation- and colony-forming assays. We are currently performing transcriptome and ChIP Seq analyses to identify genes regulated by REST and possibly involved in NSC maintenance. Comparison with ES cell-derived NSC genome and transcriptome-wide analyses will help to define difference in Rest binding and/or regulative capability between embryonic and adult NSC.