[Function of glial cell network as a modulator of neural cell death during retinal degeneration].
OBJECTIVE
Recent studies have demonstrated the mechanism of neural cell death, neuroprotection, and regeneration. However, the functional importance of glial cells during retinal degeneration is not well understood. In this review, we summarize our recent progress regarding the function of glial cells in neurotrophic factor production and neural cell death during retinal degeneration.


METHODS
We made a rat model of photoreceptor degeneration by continuous light exposure, and examined the distribution and expression levels of neurotrophins and their receptors. In addition, we carried out quantitative analysis of neurotrophic factor production in cultured Müller glial cells and microglia.


RESULTS
In the light-degenerated retina, microglia invade the photoreceptor layer from the inner part of the retina and increase the production of nerve growth factor (NGF). NGF decreases the production of basic fibroblast growth, factor, which prevents photoreceptor cell death, in Müller glial cells through low-affinity neurotrophin receptor p 75. Blockade of p 75 decreased photoreceptor cell death during light-induced retinal degeneration.


CONCLUSIONS
These results suggest that a gliaglia network plays a critical role in neural cell death during retinal degeneration. Thus, a glia-glia network as well as a glia-neuron network could be a possible therapeutic target for inhibition of retinal degeneration.
Harada
Takayuki
T
Department of Molecular Neurobiology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu 183-8526, Japan.
Harada
Chikako
C
D000818:Animals; D016923:Cell Death; D002478:Cells, Cultured; D009414:Nerve Growth Factors / Q000096:biosynthesis; D009415:Nerve Net / Q000502:physiology; D009457:Neuroglia / Q000502:physiology*; D009474:Neurons / Q000473:pathology*; D051381:Rats; D012162:Retinal Degeneration / Q000473:pathology*
D009414:Nerve Growth Factors