Growth factors

Neurotrophins induce death of hippocampal neurons via the p75 receptor.  Friedman, W. J. J. Neurosci. 20 , 6340-6346 (2000) . [Pubmed]

The ability of nerve growth factor to elicit cell death by binding to its low-affinity receptor had been documented previously. Here Friedman extends this observation by showing that brain-derived neurotrophic factor, and the neurotrophins 3 and 4 can also induce the death of hippocampal neurons in culture. This effect requires binding to the p75 receptor; it does not occur if the cells express the high-affinity neurotrophin receptors, and it seems to require Jun kinase activation. It will be of interest to see if a similar effect can be shown in vivo.

Brain repair

Xenotransplantation of transgenic pig olfactory ensheathing cells promotes axonal regeneration in rat spinal cord. Imaizumi, T. et al. Nature Biotechnol. 18 , 949–953 (2000). [Abstract]

The use of olfactory ensheathing cells (OEC) has become a promising tool to promote axon regeneration. Here the authors isolated OEC from transgenic pigs expressing a human complement inhibitory protein, and xenografted them to the rat spinal cord. The grafts promoted axon regeneration comparable to that observed for allografts, highlighting the potential of transgenic OEC for xenotransplantation and possible therapeutic use.


GATA2 is required for the generation of V2 interneurons.  Zhou, Y. et al. Development 127 , 3829–3838 (2000). [Pubmed]

GATA2 is a transcription factor involved in haematopoiesis. GATA2 is also expressed in the developing brain but its role is unknown. The authors show that GATA2 is expressed in postmitotic V2 interneurons of the spinal cord, that this cell type is absent in Gata2 knockout mice, and that the spinal cord expression of Gata2 is controlled by a 190-base pair enhancer. As Gata2 knockouts die early in development, selective deletion of this enhancer should lead to the elucidation of the functional role of V2 interneurons.


Modulation of human visual cortex by crossmodal spatial attention.  Macaluso, E. et al. Science 289 , 1206–1208 (2000). [Pubmed]

A touch to one hand can increase ipsilateral visual discrimination, a phenomenon thought to engage multimodal cortical regions. Using functional magnetic resonance imaging (fMRI), the authors find that the activity of a unimodal visual region — the lingual gyrus — is also increased if a visual stimulus to the right hemifield is accompanied by a touch to the right hand. The authors suggest that back-projections from multimodal parietal regions effectively connected to the visual cortex might be responsible for the crossmodal interactions in a unimodal cortex.