Transcriptional Regulation of Olfactory Bulb Neurogenesis

Abstract

The neurons in the olfactory bulb originate from molecularly defined and spatially distinct proliferative regions. Glutamatergic projection neurons are generated during the embryonic period in the local ventricular zone of the olfactory bulb, a territory in the dorsal telencephalon in which the transcription factor Pax6 is expressed. Some cells in this zone also express Tbr1, a marker of glutamatergic neurons. By contrast, embryonic olfactory bulb interneurons are derived from Gsx2 expressing cells in the dorsal lateral ganglionic eminence of the ventral telencephalon, and from progenitors outside the dorsal lateral ganglionic eminence, including the olfactory bulb neuroepithelium. Postnatally, interneurons arise from the subventricular zone of the lateral ventricle, although the rostral migratory stream and the olfactory bulb also appear to serve as a source of neurons. Transcription factors are crucial to generate all classes of neurons and glia in the olfactory bulb, both during development and adulthood. In this article, we discuss and propose models on how the spatial and temporal regulation of transcription factor expression controls the self-renewal, proliferation and cell fate of neural stem cells and progenitors, which finally leads to the generation of distinct functional subtypes of neurons in the developing and adult olfactory bulb. Anat Rec, 296:1364Rec, 296: -1382Rec, 296: , 2013. V C 2013 Wiley Periodicals, Inc.Key words: olfactory bulb; neurogenesis; transcription factor; neural stem cells; proliferation; differentiation

In Vitro Evaluation of Biocompatibility of Uncoated Thermally Reduced Graphene and Carbon Nanotube-Loaded PVDF Membranes with Adult Neural Stem Cell-Derived Neurons and Glia

“…The greater percentages of astrocytes differentiating from aOBSCs compared to those of neurons and oligodendrocytes are consistent with previous findings on the differentiation of aNSCs (Gritti et al, 2002; Sanai et al, 2004; Vergaño-Vera et al, 2009; Nieto-Estévez et al, 2013). Next, we investigated the effect of TRG on the expression of a key neurogenic gene, Ngn1 , and of genes involved in the generation of astrocytes ( Hes5 ) and oligodendrocytes (Olig2 ) (Table 2) (Vergaño-Vera et al, 2009; Díaz-Guerra et al, 2013; Imayoshi and Kageyama, 2014). Figure 3M shows that the three transcripts were expressed in cultures differentiating for 7 days (MTD, Table 1) with no significant changes being observed between conditions in controls and TRG.…”

Pax6 Is Essential for the Maintenance and Multi-Lineage Differentiation of Neural Stem Cells, and for Neuronal Incorporation into the Adult Olfactory Bulb

“…Indeed, we previously showed that high levels of Gsx2 inhibit OBSC self-renewal. Furthermore, in the light of studies from other laboratories, we suggest that the upregulation of Gsx2 in the mutant cells can be attributed to the reduced levels of Pax6 [12,13,61].…”

“…To explore the molecular mechanisms associated to the + Sey Dey mutation, the expression of TFs involved in the regulation of self-renewal (Sox2, Gsx2, Hes1, and Hes5) [9,12,60,61] and cell proliferation, and that of markers of NSCs and progenitors (Egfr, Fgf-1r, Fgf-2r, and Nestin) [10] was measured in aOBSCs (Fig. 3).…”

“…In addition to these functions in brain patterning, Pax6 regulates the proliferation, self-renewal, differentiation, and apoptosis of embryonic NSCs and progenitor cells in multiple brain regions [19][20][21][22][23][24][25][26][27]. However, a few studies have evaluated the role of this TF in the maintenance and cell fate of NSCs from the adult SVZ and hippocampus [28][29][30], and no studies have yet been published on the putative role of Pax6 in NSCs isolated from the adult OB [12].…”

“…Additional sources of interneurons may include the elbow of the rostral migratory stream (RMS) and the OB itself [4][5][6][7][8][9][10][11]. Adult neurogenesis is tightly regulated by both cell extrinsic and intrinsic mechanisms, among which transcription factors (TFs) play a major role, participating in several aspects of NSC maintenance, fate choice, and neuronal differentiation [12].…”