Project description:XBP1 is a transcription factor that is induced by unconventional splicing associated with endoplasmic reticulum stress and plays a role in development of liver and plasma cells. We previously reported that brain derived neurotrophic factor (BDNF) leads to splicing of XBP1 mRNA in neurites, and that XBP1 is required for BDNF-induced neurite extension and branching. To search for the molecular mechanisms of how XBP1 plays a role in neural development, comprehensive gene expression analysis was performed in primary telencephalic neurons obtained from Xbp1 knockout mice at embryonic day 12.5. By searching for the genes induced by BDNF in wild type neurons but this induction was reduced in Xbp1 knockout mice, we found that upregulation of three GABAergic markers, somatostatin (Sst), neuropeptide Y (Npy), and calbindin (Calb1), were compromised in Xbp1 knockout neurons. Attenuated induction of Npy and Calb1 was confirmed by quantitative RT-PCR. In neurons lacking in Xbp1, upregulation of GABAergic markers was attenuated. Impaired BDNF-induced neurite extension in Xbp1 knockout neurons might be mediated by disturbed BDNF-induced differentiation of GABAergic interneurons. Keywords: time-cource, genetic modification
Project description:Specific neuronal types derived from embryonic stem cells (ESCs) can facilitate mechanistic studies and potentially aid in regenerative medicine. Existing induction methods, however, mostly rely on the effects of growth factors, which generally tend to result in mixed populations of neurons. Here we report that over-expression of specific transcription factors (TFs) in ESCs can rather guide the differentiation of ESCs towards specific neuron types. Analysis of published data on gene expression changes early (two days) after induction of each of 185 induced TFs implicated candidate TFs for further ESC differentiation studies. After induction for 6 days four of them (Ascl1, Smad7, Nr2f1, and Ascl2) generated a high proportion (>35%) of cells with neural progenitor marker PSA-NCAM and clear neural morphology on day 14. The capacity of these TFs to induce neural differentiation is inferred to be most likely linked to early activation of the Notch signaling pathway. Among the neuron-like cells, GABA-positive cells were most abundant (32-97% for 4 top TFs), whereas Isl1-positive cells and TH-positive cells were less abundant (<12% and <5%, respectively). Enrichment of cells obtained with the induction of Ascl1, Smad7, and Nr2f1 using beads with anti-PSA-NCAM antibody resulted in essentially pure population of neuron-like cells with expression profiles similar to neural tissues and highly expressed markers of GABAergic neurons. A time-course experiment with induction of Ascl1 showed early upregulation of most neural-specific and GABAergic-specific mRNA and miRNAs. We identified mRNA and miRNAs, whose expression depended on the induction of Ascl1, and showed that they were enriched in Ascl1 target genes. In summary, this study indicates that induction of transcription factors is a promising approach to generate candidate specific neural cell types from ESCs. Transcription factor Ascl1 was induced in mouse ESCs to facilitate neural differentiation. Expression of transgenic Ascl1 was repressed by doxycycline (Dox); thus, it were induced in Dox- conditions, whereas Dox+ conditions represent control cells with no expression of Ascl1 transgene. For neural differentiation, cells were cultured 3 days in alpha-MEM medium and then - in NeuroCult neural differentiation medium for 2-11 days (total up to 14 days). RNA was extracted with mirVana kit (Thermo Fisher Scientific).
Project description:Direct neuronal conversion describes the process of generating induced neurons from somatic cells such as fibroblasts by overexpressing cell type-specific transcription factors. This was first achieved by expressing Brn2, Ascl1 and MytL1 in mouse fibroblasts, and was later achieved in human cells by inclusion of additional factors such as NeuroD1. Here, we present the first protocol for directly converting porcine fibroblasts into induced neurons. We used lentivirus-mediated delivery of previously identified neuronal-specifying transcription factors and microRNAs and evaluated morphology and neuronal marker expression after ten days of conversion. We found that Ascl1 and microRNAs, miR-9/9* and miR-124 together generated more neuronal cells than other conditions tested. The porcine induced neurons expressed common mature markers such as MAP2 and Synaptophysin after four weeks of conversion. Transcriptomic analysis revealed that fibroblast-specific signatures were silenced early in the conversion process, while the neuronal programs increased and matured during conversion. We generated a heterogenous population of glutamatergic and GABAergic neurons.
Project description:Rationale: A previous transcriptome meta-analysis revealed significantly lower levels of corticotropin-releasing hormone (CRH) mRNA in corticolimbic brain regions in major depressive disorder (MDD) subjects. Rodent studies show that cortical CRH is mostly expressed in GABAergic neurons; however, the characteristic features of CRH+ cells in human brain cortex and their association with MDD are largely unknown. Methods: Subgenual anterior cingulate cortex (sgACC) of human subjects without brain disorders were labeled using fluorescent in situ hybridization (FISH) for CRH and markers of excitatory (SLC17A7), inhibitory (GAD1) neurons, as well as markers of other interneuron subpopulations (PVALB, SST, VIP). MDD-associated changes in CRH+ cell density and cellular CRH expression (n=6/group) were analyzed. RNA-sequencing was performed on sgACC CRH+ neurons from comparison and MDD subjects (n=6/group), and analyzed for group differences. Results: About 80% of CRH+ cells were GABAergic and 17.5% were glutamatergic. CRH+ GABAergic neurons co-expressed VIP (52%), SST (7%), or PVALB (7%). MDD subjects displayed lower CRH mRNA levels in GABAergic neurons relative to comparison subjects without changes in cell density. CRH+ neurons show transcriptomic profile suggesting lower excitability and less GABA release and reuptake. Further analyses suggested that these molecular changes are not mediated by altered glucocorticoid feedback and potentially occur downstream for a common modulator of neurotrophic function. Summary: CRH+ cells in human sgACC are a heterogeneous population of GABAergic neurons, although largely co-expressing VIP. MDD is associated with reduced markers of inhibitory function of CRH+ neurons.
Project description:Specific neuronal types derived from embryonic stem cells (ESCs) can facilitate mechanistic studies and potentially aid in regenerative medicine. Existing induction methods, however, mostly rely on the effects of growth factors, which generally tend to result in mixed populations of neurons. Here we report that over-expression of specific transcription factors (TFs) in ESCs can rather guide the differentiation of ESCs towards specific neuron types. Analysis of published data on gene expression changes early (two days) after induction of each of 185 induced TFs implicated candidate TFs for further ESC differentiation studies. After induction for 6 days four of them (Ascl1, Smad7, Nr2f1, and Ascl2) generated a high proportion (>35%) of cells with neural progenitor marker PSA-NCAM and clear neural morphology on day 14. The capacity of these TFs to induce neural differentiation is inferred to be most likely linked to early activation of the Notch signaling pathway. Among the neuron-like cells, GABA-positive cells were most abundant (32-97% for 4 top TFs), whereas Isl1-positive cells and TH-positive cells were less abundant (<12% and <5%, respectively). Enrichment of cells obtained with the induction of Ascl1, Smad7, and Nr2f1 using beads with anti-PSA-NCAM antibody resulted in essentially pure population of neuron-like cells with expression profiles similar to neural tissues and highly expressed markers of GABAergic neurons. A time-course experiment with induction of Ascl1 showed early upregulation of most neural-specific and GABAergic-specific mRNA and miRNAs. We identified mRNA and miRNAs, whose expression depended on the induction of Ascl1, and showed that they were enriched in Ascl1 target genes. In summary, this study indicates that induction of transcription factors is a promising approach to generate candidate specific neural cell types from ESCs. Individual transcription factors (TFs) (Ascl1, Smad7, and Nr2f1) were induced in mouse ESCs to facilitate neural differentiation. Expression of transgenic TFs was repressed by doxycycline (Dox); thus, TFs were induced in Dox- conditions, whereas Dox+ conditions represent control cells with no expression of a transgene. For neural differentiation, cells were cultured 3 days in alpha-MEM medium and then in NeuroCult neural differentiation medium. Cells marked as PSANCAM+ were enriched by magnetic microbeads with anty-PSA-NCAM antibody (Miltenyi Biotec) on day 6 of culturing, whereas remaining cells are marked as PSANCAM-. Both PSANCAM+ and PSANCAM- cells were then cultured for another 8 days (total 14 days in differentiation). A time course experiment with Ascl1 induction did not include cell enrichment procedure. RNA was extracted with either Trizol (invitrogen) or mirVana kit (Thermo Fisher Scientific).
Project description:Specific neuronal types derived from embryonic stem cells (ESCs) can facilitate mechanistic studies and potentially aid in regenerative medicine. Existing induction methods, however, mostly rely on the effects of growth factors, which generally tend to result in mixed populations of neurons. Here we report that over-expression of specific transcription factors (TFs) in ESCs can rather guide the differentiation of ESCs towards specific neuron types. Analysis of published data on gene expression changes early (two days) after induction of each of 185 induced TFs implicated candidate TFs for further ESC differentiation studies. After induction for 6 days four of them (Ascl1, Smad7, Nr2f1, and Ascl2) generated a high proportion (>35%) of cells with neural progenitor marker PSA-NCAM and clear neural morphology on day 14. The capacity of these TFs to induce neural differentiation is inferred to be most likely linked to early activation of the Notch signaling pathway. Among the neuron-like cells, GABA-positive cells were most abundant (32-97% for 4 top TFs), whereas Isl1-positive cells and TH-positive cells were less abundant (<12% and <5%, respectively). Enrichment of cells obtained with the induction of Ascl1, Smad7, and Nr2f1 using beads with anti-PSA-NCAM antibody resulted in essentially pure population of neuron-like cells with expression profiles similar to neural tissues and highly expressed markers of GABAergic neurons. A time-course experiment with induction of Ascl1 showed early upregulation of most neural-specific and GABAergic-specific mRNA and miRNAs. We identified mRNA and miRNAs, whose expression depended on the induction of Ascl1, and showed that they were enriched in Ascl1 target genes. In summary, this study indicates that induction of transcription factors is a promising approach to generate candidate specific neural cell types from ESCs.
Project description:Specific neuronal types derived from embryonic stem cells (ESCs) can facilitate mechanistic studies and potentially aid in regenerative medicine. Existing induction methods, however, mostly rely on the effects of growth factors, which generally tend to result in mixed populations of neurons. Here we report that over-expression of specific transcription factors (TFs) in ESCs can rather guide the differentiation of ESCs towards specific neuron types. Analysis of published data on gene expression changes early (two days) after induction of each of 185 induced TFs implicated candidate TFs for further ESC differentiation studies. After induction for 6 days four of them (Ascl1, Smad7, Nr2f1, and Ascl2) generated a high proportion (>35%) of cells with neural progenitor marker PSA-NCAM and clear neural morphology on day 14. The capacity of these TFs to induce neural differentiation is inferred to be most likely linked to early activation of the Notch signaling pathway. Among the neuron-like cells, GABA-positive cells were most abundant (32-97% for 4 top TFs), whereas Isl1-positive cells and TH-positive cells were less abundant (<12% and <5%, respectively). Enrichment of cells obtained with the induction of Ascl1, Smad7, and Nr2f1 using beads with anti-PSA-NCAM antibody resulted in essentially pure population of neuron-like cells with expression profiles similar to neural tissues and highly expressed markers of GABAergic neurons. A time-course experiment with induction of Ascl1 showed early upregulation of most neural-specific and GABAergic-specific mRNA and miRNAs. We identified mRNA and miRNAs, whose expression depended on the induction of Ascl1, and showed that they were enriched in Ascl1 target genes. In summary, this study indicates that induction of transcription factors is a promising approach to generate candidate specific neural cell types from ESCs.