Neural Cell News Volume 8.19 | May 21 2014

Cell-Intrinsic Requirement of Dscam1 Isoform Diversity for Axon Collateral Formation
A canonical model suggests that homophilic binding of identical Dscam1 receptor isoforms on sister dendrites ensures self-avoidance even when just a single isoform is expressed. Investigators report on a cell-intrinsic function requiring the co-expression of multiple isoforms. Manipulation of the Dscam1 isoform pool in single neurons causes severe disruption of collateral formation of mechanosensory axons. [Science] Abstract

A Role for Melanopsin in Alpha Retinal Ganglion Cells and Contrast Detection
Researchers showed that the ON alpha retinal ganglion cell (RGC), a conventional RGC type, is intrinsically photosensitive in mammals. In addition to their classical response to fast changes in contrast through rod/cone signaling, melanopsin expression allows ON alpha RGCs to signal prior light exposure and environmental luminance over long periods of time. [Neuron] Abstract | Press Release | Video

Inhibition of Mitochondrial Protein Import by Mutant Huntingtin
Investigators identified an interaction between mutant huntingtin (Htt) and the TIM23 mitochondrial protein import complex. Mitochondria from brain synaptosomes of presymptomatic Huntington’s disease (HD) model mice and from mutant Htt-expressing primary neurons exhibited a protein import defect, suggesting that deficient protein import is an early event in HD. [Nat Neurosci] Abstract | Press Release

Two-Photon Imaging of Remyelination of Spinal Cord Axons by Engrafted Neural Precursor Cells in a Viral Model of Multiple Sclerosis
Using two-photon imaging of a newly developed ventral spinal cord preparation and a viral model of demyelination, researchers described the motility and intercellular interactions of transplanted mouse neural precursor cells expressing green fluorescent protein with damaged axons expressing yellow fluorescent protein. [Proc Natl Acad Sci USA] Abstract

The Zinc Finger Transcription Factor ZFX Is Required for Maintaining the Tumorigenic Potential of Glioblastoma Stem Cells
Scientists demonstrated that the zinc finger and X-linked transcription factor (ZFX) maintains glioma stem cell self-renewal and tumorigenic potential by up-regulating c-Myc expression. [Stem Cells] Abstract

ROCK2 Is a Major Regulator of Axonal Degeneration, Neuronal Death and Axonal Regeneration in the CNS
Researchers showed that specific knockdown of Rho-associated protein kinase 2 (ROCK2) and LIM domain kinase-1 equally enhanced neurite outgrowth of retinal ganglion cells on inhibitory substrates and both induced substantial neuronal regeneration over distances of more than 5 mm after rat optic nerve crush in vivo. [Cell Death Dis] Full Article

Tcf3 Represses Wnt-β-Catenin Signaling and Maintains Neural Stem Cell Population during Neocortical Development
Results suggest that Tcf3 antagonizes Wnt signaling in neural precursor cells, thereby maintaining their undifferentiated state in the neocortex and that Wnt signaling promotes the transition from Tcf3-mediated repression to Tcf1/Lef1-mediated enhancement of Wnt signaling, constituting a positive feedback loop that facilitates neuronal differentiation. [PLoS One] Full Article

Human Neural Precursor Cells Promote Neurologic Recovery in a Viral Model of Multiple Sclerosis
Using a viral model of the demyelinating disease multiple sclerosis, researchers showed that intraspinal transplantation of human embryonic stem cell-derived neural precursor cells (hNPCs) results in sustained clinical recovery, although hNPCs were not detectable beyond day eight posttransplantation. [Stem Cell Rep]
Abstract | Full Article | Press Release

Gene Therapy Section Formed within the Alliance for Regenerative Medicine
The Alliance for Regenerative Medicine (ARM) and the American Society of Gene & Cell Therapy (ASGCT) announced their partnership. ARM’s new Gene and Gene-Modified Cell Therapy Section brings together the leading gene therapy companies and organizations in the U.S. and Europe to advocate for policies and programs to accelerate the development of new therapeutics to treat and cure a range of diseases for which no effective treatment options are available. [Alliance for Regenerative Medicine] Press Release