RNA expression in aOBSCs reveals previously undescribed genes involved in NSC death, survival and the initiation of differentiation.

<p>aOBSCs (prepared from 7- and 15-month old mice) were cultured and passaged as floating neurospheres as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053594#pone-0053594-g001" target="_blank">Fig. 1</a>. The relative mRNA levels were analyzed using microarray and real time RT-qPCR techniques. (<b>A</b>) The heat map was generated using probes with a range of variation between samples of at least 2 and a FDR <0.01. The color bar at the top represents the gene expression in a log₂ scale: the higher the gene expression level, the redder the color. (<b>B</b>) Pairwise scatter plots of the C2 (top) and C4 (lower) conditions relative to the Ctr condition. The black lines define the boundaries of the two-fold changes in gene expression between paired samples. Genes up-regulated in ordinate versus abscissas samples are shown in red circles, while down-regulated genes are shown in green. Orange dots indicate the positions of some key genes, including markers of NSCs (<i>Sox2</i> and <i>Pax6</i>) and of upregulated genes (<i>Cox6a2, Pla2g7, Cryab, Ndrg2, Dscaml1 and Gpr17</i>). The color bar to the right indicates the scattering density, whereby the higher the scattering density, the darker the blue color. (<b>C</b>) The pie chart shows the frequency of GO terms in the “biological process” category. (<b>D</b>) GO enrichment analysis revealed up to 10 GO terms that were statistically enriched in C4 cultures when compared with the controls. (<b>E</b>) The graph shows the relative changes in the mRNA levels of selected transcripts expressed in C2 and C4 cultures when compared with controls, and as measured by real time RT-qPCR. The aOBSCs supplemented every 4 days with growth factors exhibited alterations in genes involved in cell death and survival (<i>Cryab</i>), lipid catabolic processes (<i>Pla2g7</i>), cell adhesion (<i>Dscaml1</i>), cell differentiation (<i>Dscaml1</i>, <i>Gpr17</i>, <i>S100b, Ndrg2</i>) and signal transduction (<i>Gpr17</i>, <i>Ndrg2).</i> The results represent the mean ± SEM of 3 experiments.