Neural Cell News Volume 7.26 | Jul 3 2013

The Phosphatase PP4c Controls Spindle Orientation to Maintain Proliferative Symmetric Divisions in the Developing Neocortex
In the developing neocortex, progenitor cells expand through symmetric division before they generate cortical neurons through multiple rounds of asymmetric cell division. Researchers showed that the orientation of the mitotic spindle plays a crucial role in regulating the transition between those two division modes. They demonstrated that the protein phosphatase PP4c regulates spindle orientation in early cortical progenitor cells. [Neuron] Abstract | Full Article

Differential Innervation of Direct- and Indirect-Pathway Striatal Projection Neurons
Scientists used a monosynaptic rabies virus system to generate brain-wide maps of neurons that form synapses with direct- or indirect-pathway striatal projection neurons. They discovered that sensory cortical and limbic structures preferentially innervated the direct pathway, whereas motor cortex preferentially targeted the indirect pathway. [Neuron] Abstract | Press Release

Arl13b-Regulated Cilia Activities Are Essential for Polarized Radial Glial Scaffold Formation
Using developmental stage-specific deletion of Arl13b in mouse cortical progenitors, researchers found that early neuroepithelial deletion of ciliary Arl13b led to a reversal of the apical-basal polarity of radial progenitors and aberrant neuronal placement. [Nat Neurosci] Abstract | Press Release

a-Tanycytes of the Adult Hypothalamic Third Ventricle Include Distinct Populations of FGF-Responsive Neural Progenitors
Investigators identified a-tanycytes as key components of a hypothalamic niche in the adult mouse. In vitro studies demonstrated that a-tanycytes, but not ß-tanycytes or parenchymal cells, are neurospherogenic. Distinct subpopulations of a-tanycytes exist, amongst which only GFAP-positive dorsal a2-tanycytes possess stem-like neurospherogenic activity. [Nat Commun] Full Article | Press Release

Severing and End-to-End Annealing of Neurofilaments in Neurons
Researchers have shown previously that neurofilaments and vimentin filaments expressed in nonneuronal cell lines can lengthen by joining ends in a process known as “end-to-end annealing.” To test if this also occurs for neurofilaments in neurons, they transfected cultured rat cortical neurons with fluorescent neurofilament fusion proteins and then used photoconversion or photoactivation strategies to create distinct populations of red and green fluorescent filaments. [Proc Natl Acad Sci USA] Abstract

Histone Deacetylase 5 Blocks Neuroblastoma Cell Differentiation by Interacting with N-Myc
Researchers showed that N-Myc upregulated histone deacetylase 5 (HDAC5) expression in neuroblastoma cells. Conversely, HDAC5 repressed the ubiquitin-protein ligase NEDD4 gene expression, increased Aurora A gene expression and consequently upregulated N-Myc protein expression. [Oncogene] Abstract

Mcl1 Regulates the Terminal Mitosis of Neural Precursor Cells in the Mammalian Brain through p27^Kip1
Scientists showed in mice that myeloid cell leukemia 1 (Mcl1), an anti-apoptotic Bcl-2 protein required for the survival of neural precursor cell, also regulates their terminal differentiation through the cell cycle regulator p27^Kip1. [Development] Abstract

MicroRNA-195 Targets ADP-Ribosylation Factor-Like Protein 2 to Induce Apoptosis in Human Embryonic Stem Cell-Derived Neural Progenitor Cells
Scientists defined the proapoptotic role of microRNA-195 (miR-195) in neural progenitor cells (NPCs) derived from two independent human embryonic stem cell (hESC) lines. Overexpression of miR-195 in hESC-NPCs induced extensive apoptotic cell death. [Cell Death Dis] Full Article

BACE1 Regulates Hippocampal Astrogenesis via the Jagged1-Notch Pathway
Researchers revealed that BACE1 directly regulates the level of membrane-anchored full-length Jagged1 (Jag1), a signaling molecule important for the control of neurogenesis and astrogenesis, via interaction with its cognate Notch receptor. They showed that shedding of Jag1 is reduced in BACE1 null mice and upregulated Jag1 enhances Notch signaling via cell-cell juxtacrine interactions. [Cell Rep]
Abstract | Graphical Abstract | Full Article

Mature Neurons: Equipped for Survival
As many neurodegenerative diseases afflict adult neuronal populations, the survival mechanisms in mature neurons are likely to be either reversed or circumvented during neurodegeneration. Examining the adaptations for inhibiting apoptosis during neuronal maturation is key to comprehending not just how neurons survive long term, but may also provide insight for understanding how neuronal toxicity in various neurodegenerative diseases may ultimately lead to cell death. [Cell Death Dis] Full Article

Parkinson’s Disease Foundation Awards $1 Million to Help Reveal Causes, Advance Therapies and End Parkinson’s
The Parkinson’s Disease Foundation® announced $1 million in funding for 14 global research projects designed to improve the lives and futures of people touched by Parkinson’s disease. [The Parkinson’s Disease Foundation] Press Release

National MS Society Commits $2.5 Million for Research by Pediatric MS Network
The National Multiple Sclerosis (MS) Society has just committed $2.5 million to support research by the Network of Pediatric MS Centers beginning July 1, 2013. Funding for the nine-center network provides essential infrastructure to facilitate research, including searching for the cause of MS by studying risk factors for the disease in children, close to the time of exposure. [The National Multiple Sclerosis Society]
Press Release

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