Neurotrophin-4/5 promotes survival and differentiation of rat striatal neurons developing in culture.
Cultures of dissociated striatal neurons from fetal rats were prepared, and were grown in the presence of neurotrophin-4/5 (NT-4/5) as well as the other known neurotrophins, nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3). We found that acute administration of NT-4/5 to 7-day-old cultures stimulates the hydrolysis of phosphatidylinositol, an event involved in neurotrophin signal transduction. Growth of striatal cultures in the presence of NT-4/5 resulted in increased cell survival, as indicated by elevations in cell number, protein content, and a measure of mitochondrial enzyme activity (MTT assay). NT-4/5 increased GABA uptake and staining intensity in these cultures, as indicated by GABA immunocytochemistry, indicating a trophic action on GABAergic neurons, the predominant neuron type in the striatum. To further identify responsive cell populations we analysed for calretinin, a calcium-binding protein known to colocalize with GABA in a number of neuronal cells. In cultures prepared from rats of embryonic day 15, NT-4/5 strongly increased the number of calretinin-positive cells as well as calretinin levels, as determined by Western blot analysis. When the cultures were prepared from embryonic day 18 rats, NT-4/5 very strongly increased the morphological differentiation of calretinin-positive cells, whereas the increase in cell number was less prominent. All effects produced by NT-4/5 were mimicked by BDNF with similar potency. NT-3 was less effective than NT-4/5 and BDNF, and its effects were limited to cultures prepared from embryonic day 15 rats, suggesting a role in the regulation of cell survival at early developmental stages. NGF did not affect any of the measured parameters. Our findings identify NT-4/5 as potent neurotrophic factor for striatal neurons, able to promote their survival and differentiation.
Widmer
H R
HR
Division of Neurogerontology, Andrus Gerontology Center, University of Southern California, Los Angeles 90089.
Hefti
F
F
D000818:Animals; D015153:Blotting, Western; D064032:Calbindin 2; D002454:Cell Differentiation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D006801:Humans; D007150:Immunohistochemistry; D017072:Neostriatum / Q000166:cytology* / Q000187:drug effects; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects*; D010716:Phosphatidylinositols / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000494:pharmacology; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D013778:Tetrazolium Salts; D013844:Thiazoles; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
C576764:CALB2 protein, human; C576512:Calb2 protein, rat; D064032:Calbindin 2; D009414:Nerve Growth Factors; D010716:Phosphatidylinositols; D011994:Recombinant Proteins; D064030:S100 Calcium Binding Protein G; D013778:Tetrazolium Salts; D013844:Thiazoles; C071951:neurotrophin 5; D005680:gamma-Aminobutyric Acid; D004247:DNA; C022616:thiazolyl blue; C073922:neurotrophin 4