br Results br Discussion In the present study we

Results
Discussion In the present study, we have shown that HPCA is an important regulator of the neuronal differentiation of NSCs and that it promotes neurogenesis and inhibits gliogenesis. HPCA expression markedly increased during differentiation of NSCs isolated from the cerebral cortex in the E14 rat brain. In addition, neurite outgrowth was enhanced by overexpression of Hpca, indicating that HPCA could be an important player in neuronal differentiation in the brain. Studies of the signal transduction pathways that lead to neuronal differentiation have been impeded by limitations in the genetic manipulation and biochemical analysis of primary neuronal cells, including NSCs. Nevertheless, we have identified a mechanism of HPCA action that promotes neurogenesis. HPCA recruits PKCα to PDK1, which facilitates the PKCα-regulated kinase cascade; PKCα-dependent PLD1 activation is required for HPCA-mediated neurite outgrowth. PA, a functional product of PLD1, affects tyrosine phosphatase SHP-1 activation during neuronal differentiation, and SHP-1 blocks STAT3(Y705) activation, thereby inhibiting gliogenesis in NSCs (Figure 7I). Thus, this signaling pathway provides insight into HPCA-mediated neuronal function in rat NSCs and its potential contribution to cell-fate signaling.
Experimental Procedures
Author Contributions
Acknowledgments We owe great thanks to Dr. Mi-Ryoung Song (Gwangju Institute of Science and Technology, Gwangju, Republic of Korea) for Stat3 plasmids. This work was supported by a Medical Research Center program (NRF-2012R1A5A2A34671243) of the Ministry of Science and Technology, Republic of Korea, and partly supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT and Future Planning (2015R1C1A1A02037376).
Introduction Human buy 3-Deazaneplanocin A development begins with the differentiation of neural progenitor cells in the third gestational week and extends through to adolescence (Stiles and Jernigan, 2010). The first cells committed to a neural fate appear during gastrulation in a single sheet of cells with epithelial features (Stern, 2005). These neuroepithelial stem (NES) cells then differentiate further into multiple types of cells, including neurons, astrocytes, and other glial cells (Temple, 2001). The brain is the most complex organ and its formation requires a tight control of lineage-specific differentiation pathways. To date many transcriptional networks have been identified as important regulators of lineage specification, yet little is known about the function of posttranscriptional regulation in the developing brain. Gene expression is dynamically controlled through reversible chemical modifications in DNA and histones (Bannister and Kouzarides, 2011; Deaton and Bird, 2011). Covalent modifications are also commonly found in RNA, but their precise role in regulating gene expression and translation remains less well understood. However, RNA modifications are crucial for development and aberrant deposition of RNA modifications can lead to complex human diseases, including neurodevelopmental disorders and cancer (Frye and Blanco, 2016; Popis et al., 2016). Many of the more than 100 known chemical modifications found in RNA have been described decades ago (Machnicka et al., 2013), but their potentially very broad roles in regulating RNA metabolism emerged only recently. Novel transcriptome-wide approaches revealed vital roles for pseudouridine, N6-methyladenosine, N1-methyladenosine, and 5-methylcytosine (m5C) in posttranscriptional gene regulation (Carlile et al., 2014; Dominissini et al., 2012, 2016; Hussain et al., 2013a; Khoddami and Cairns, 2013; Lovejoy et al., 2014; Meyer et al., 2012; Schwartz et al., 2014). Cytosine-5 methylation in RNA is mediated by a large protein family of conserved RNA:m5C-methyltransferases (Motorin et al., 2010). NSUN2 is one member of this family and methylates the vast majority of tRNAs as well as a small number of other non-coding (ncRNAs) and coding RNAs (cRNAs) (Blanco et al., 2014; Hussain et al., 2013a; Khoddami and Cairns, 2013). Loss of NSUN2-mediated methylation of tRNAs increases their affinity to the endonuclease angiogenin, resulting in increased cleavage of tRNAs and accumulation of 5′ tRNA fragments (Blanco et al., 2014, 2016). The function of tRNA-derived ncRNA fragments is to repress global protein translation (Gebetsberger et al., 2012; Ivanov et al., 2011).