- Email: [email protected]
progenitor cells
S32
Abstract / Differentiation 80 (2010) S17–S63
division of neuroblasts. PP2A complex regulates asymmetric localization of Numb, Pon and atypical protein kinase C as well as proper mitotic spindle orientation. Interestingly, PP2A and Polo kinase enhance Numb and Pon phosphorylation. PP2A, like Polo, acts to prevent excess neuroblast self-renewal primarily by regulating asymmetric localization/activation of Numb. Reduction of PP2A function in larval brains or S2 cells causes a marked decrease in Polo transcript and protein abundance. Overexpression of Polo or Numb significantly suppresses neuroblast overgrowth in PP2A mutants, suggesting that PP2A inhibits excess neuroblast self-renewal in Polo/Numb pathway. We will also discuss about novel players in asymmetric division that we have identified from genetics screens.
P46 Generation of transgenic mice for the inducible expansion of neural stem cells
Miki Nonaka, Federico Calegari DFG-Research Center and Cluster of Excellence for Regenerative Therapies Dresden (CRTD), Medical Faculty, Technische Universit¨ at Dresden, Germany E-mail addresses: [email protected] (M. Nonaka), [email protected] (F. Calegari)
doi: 10.1016/j.diff.2010.09.050
P45 Functional analysis of macrophage migration inhibitory factor (MIF) in the mouse neural stem/progenitor cells
S. Ohta a, Y. Kawakami a, H. Okano b, M. Toda c a
Center for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan b Department of Physiology, Keio University School of Medicine, Tokyo, Japan c Department of Neurosurgery, Keio University School of Medicine, Tokyo, Japan E-mail address: [email protected] (S. Ohta)
In previous studies, we demonstrated that mouse dendritic cells (DCs) can increase the number of neural stem/progenitor cells (NSPCs) in vitro and in vivo (JNR 2004; 76: 453–465). We identified migration inhibitory factor (MIF) that is secreted from DCs and NSPCs as a novel factor that can support the proliferation and/or survival of NSPCs in vitro, although the function of MIF in the normal brain remains largely unknown. It was previously shown that in macrophages, MIF binds to a complex of CD74 and CD44. In the present study, we observed CD74/CD44 doublepositive cell population in mouse ganglionic eminence (GE)derived neurospheres using flow cytometry technique in vitro. We further found the expression of CD74 in GE of E14 mouse brain, suggesting the functional role of MIF in vivo. MIF increased the number of primary and secondary neurospheres. In contrast, retrovirally expressed MIF shRNAi suppressed the secondary neurosphere formations, cell proliferation, and increased the caspase3/7 activity in neurospheres. Moreover, we found that in neurospheres MIF increases the phosphorylation of Akt, Erk, AMPK, and Stat3 (Ser727) which are known as factors supporting the cell survival, proliferation and/or maintenance of NSPCs. Taken together, MIF can cause proliferation and maintain NSPCs utilizing multiple-signaling pathways synergistically and may be a new therapeutic factor for brain degeneration disorders through NSPCs activation. doi: 10.1016/j.diff.2010.09.051
During development of the mammalian brain, neurons are generated from divisions of neural stem cells. The embryonic neocortex contains two main types of neural precursors, apical progenitors (APs) and more lineage committed basal progenitors (BPs), whose expansion is believed to contribute to an increase in cortical thickness and cortical surface area, respectively, during development and evolution of the mammalian brain. The length of the cell cycle is known to influence the switch from proliferative to neuron-generating divisions of neural stem and progenitor cells. Specifically, G1 phase was shown to lengthen during neuron-generating divisions and a shortening of G1 by overexpression of the cdk4/cyclinD1 complex was shown to promote the expansion of BPs. These observations suggest that an increase in cortical surface area and, in principle, generation of mice with gyrencephalic brains, could be achieved by controlling the expression of cdk/cyclin complexes during cortical development. Therefore, we generated transgenic mouse lines for the tissue-specific, inducible, and temporally controlled overexpression of cdks/cyclins in neural precursors and investigated the effect of these manipulations on brain development, cytoarchitecture and size. Our data may provide important information on stem cell contribution to tissue formation and a better understanding of the cellular mechanisms triggering the increase in cortical surface area observed during evolution of the mammalian brain. doi: 10.1016/j.diff.2010.09.052
P47 NPR-A is essential for embryonic stem cell self-renewal and pluripotency
E.M. Abdelalim, I. Tooyama Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan E-mail address: [email protected] (E.M. Abdelalim)
The self-renewal and pluripotency of embryonic stem (ES) cells are maintained by several signaling cascades and by expression of intrinsic factors, such as Oct4, Nanog and Sox2. The mechanism that regulates these signaling cascades in ES cells is of great interest. We have recently showed that natriuretic peptide receptor A (NPR-A), which is a specific receptor for atrial and brain natriuretic peptide (ANP and BNP), is expressed in preimplantation embryos and in murine ES cells. In this study, we examined whether NPR-A is involved in the maintenance of ES cell pluripotency. Targeting of NPR-A with short interfering RNA (siRNA) resulted in phenotypic changes indicative of differentiation, downregulation of self-renewal and pluripotency factors (Oct4, Nanog and Sox2), and upregulation of differentiation genes.
Abstract / Differentiation 80 (2010) S17–S63
division of neuroblasts. PP2A complex regulates asymmetric localization of Numb, Pon and atypical protein kinase C as well as proper mitotic spindle orientation. Interestingly, PP2A and Polo kinase enhance Numb and Pon phosphorylation. PP2A, like Polo, acts to prevent excess neuroblast self-renewal primarily by regulating asymmetric localization/activation of Numb. Reduction of PP2A function in larval brains or S2 cells causes a marked decrease in Polo transcript and protein abundance. Overexpression of Polo or Numb significantly suppresses neuroblast overgrowth in PP2A mutants, suggesting that PP2A inhibits excess neuroblast self-renewal in Polo/Numb pathway. We will also discuss about novel players in asymmetric division that we have identified from genetics screens.
P46 Generation of transgenic mice for the inducible expansion of neural stem cells
Miki Nonaka, Federico Calegari DFG-Research Center and Cluster of Excellence for Regenerative Therapies Dresden (CRTD), Medical Faculty, Technische Universit¨ at Dresden, Germany E-mail addresses: [email protected] (M. Nonaka), [email protected] (F. Calegari)
doi: 10.1016/j.diff.2010.09.050
P45 Functional analysis of macrophage migration inhibitory factor (MIF) in the mouse neural stem/progenitor cells
S. Ohta a, Y. Kawakami a, H. Okano b, M. Toda c a
Center for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan b Department of Physiology, Keio University School of Medicine, Tokyo, Japan c Department of Neurosurgery, Keio University School of Medicine, Tokyo, Japan E-mail address: [email protected] (S. Ohta)
In previous studies, we demonstrated that mouse dendritic cells (DCs) can increase the number of neural stem/progenitor cells (NSPCs) in vitro and in vivo (JNR 2004; 76: 453–465). We identified migration inhibitory factor (MIF) that is secreted from DCs and NSPCs as a novel factor that can support the proliferation and/or survival of NSPCs in vitro, although the function of MIF in the normal brain remains largely unknown. It was previously shown that in macrophages, MIF binds to a complex of CD74 and CD44. In the present study, we observed CD74/CD44 doublepositive cell population in mouse ganglionic eminence (GE)derived neurospheres using flow cytometry technique in vitro. We further found the expression of CD74 in GE of E14 mouse brain, suggesting the functional role of MIF in vivo. MIF increased the number of primary and secondary neurospheres. In contrast, retrovirally expressed MIF shRNAi suppressed the secondary neurosphere formations, cell proliferation, and increased the caspase3/7 activity in neurospheres. Moreover, we found that in neurospheres MIF increases the phosphorylation of Akt, Erk, AMPK, and Stat3 (Ser727) which are known as factors supporting the cell survival, proliferation and/or maintenance of NSPCs. Taken together, MIF can cause proliferation and maintain NSPCs utilizing multiple-signaling pathways synergistically and may be a new therapeutic factor for brain degeneration disorders through NSPCs activation. doi: 10.1016/j.diff.2010.09.051
During development of the mammalian brain, neurons are generated from divisions of neural stem cells. The embryonic neocortex contains two main types of neural precursors, apical progenitors (APs) and more lineage committed basal progenitors (BPs), whose expansion is believed to contribute to an increase in cortical thickness and cortical surface area, respectively, during development and evolution of the mammalian brain. The length of the cell cycle is known to influence the switch from proliferative to neuron-generating divisions of neural stem and progenitor cells. Specifically, G1 phase was shown to lengthen during neuron-generating divisions and a shortening of G1 by overexpression of the cdk4/cyclinD1 complex was shown to promote the expansion of BPs. These observations suggest that an increase in cortical surface area and, in principle, generation of mice with gyrencephalic brains, could be achieved by controlling the expression of cdk/cyclin complexes during cortical development. Therefore, we generated transgenic mouse lines for the tissue-specific, inducible, and temporally controlled overexpression of cdks/cyclins in neural precursors and investigated the effect of these manipulations on brain development, cytoarchitecture and size. Our data may provide important information on stem cell contribution to tissue formation and a better understanding of the cellular mechanisms triggering the increase in cortical surface area observed during evolution of the mammalian brain. doi: 10.1016/j.diff.2010.09.052
P47 NPR-A is essential for embryonic stem cell self-renewal and pluripotency
E.M. Abdelalim, I. Tooyama Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan E-mail address: [email protected] (E.M. Abdelalim)
The self-renewal and pluripotency of embryonic stem (ES) cells are maintained by several signaling cascades and by expression of intrinsic factors, such as Oct4, Nanog and Sox2. The mechanism that regulates these signaling cascades in ES cells is of great interest. We have recently showed that natriuretic peptide receptor A (NPR-A), which is a specific receptor for atrial and brain natriuretic peptide (ANP and BNP), is expressed in preimplantation embryos and in murine ES cells. In this study, we examined whether NPR-A is involved in the maintenance of ES cell pluripotency. Targeting of NPR-A with short interfering RNA (siRNA) resulted in phenotypic changes indicative of differentiation, downregulation of self-renewal and pluripotency factors (Oct4, Nanog and Sox2), and upregulation of differentiation genes.