Stimulation of nerve growth factor expression in astrocytes by peroxynitrite.
BACKGROUND
Overproduction of nitric oxide (NO) has been recognized as a major mechanism of neurotoxicity. NO reacts with superoxide to generate peroxynitrite, a strong oxidizing and nitrating species. Peroxynitrite is formed in glial cells and degenerating neurons in neuropathological conditions, including amyotrophic lateral sclerosis (ALS). In ALS, motor neurons re-express the p75 neurotrophin receptor (p75NTR) and might become vulnerable to NGF. In the present study, we investigated whether peroxynitrite stimulated nerve growth factor (NGF) expression in spinal cord astrocytes.


METHODS
Astrocyte monolayers were exposed to peroxynitrite and nitrotyrosine formation was determined by immunofluorescence. mRNA levels for NGF, brain derived neutrophic factor (BDNF) and fibroblast growth factor-2 (FGF-2) were measured by semi-quantitative RT-PCR and NGF release was determined by ELISA.


CONCLUSIONS
A single exposure to peroxynitrite specifically induced NGF expression and secretion in astrocytes coincident with reactive morphological changes and increased nitrotyrosine immunoreactivity. These results suggest that NGF expression in reactive astrocytes is under the control of oxidative stress.
Vargas
Marcelo R
MR
Departamento de Neurobiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay.
Pehar
Mariana
M
Cassina
Patricia
P
Estévez
Alvaro G
AG
Beckman
Joseph S
JS
Barbeito
Luis
L
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000502:physiology*; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D016222:Fibroblast Growth Factor 2 / Q000235:genetics*; D007700:Kinetics; D020932:Nerve Growth Factor / Q000235:genetics*; D030421:Peroxynitrous Acid / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D019208:Brain-Derived Neurotrophic Factor; D012333:RNA, Messenger; D016222:Fibroblast Growth Factor 2; D030421:Peroxynitrous Acid; D020932:Nerve Growth Factor