Neurotrophic factors protect cortical synaptic terminals against amyloid and oxidative stress-induced impairment of glucose transport, glutamate transport and mitochondrial function.
Previous studies have shown that several different neurotrophic factors can prevent death of cortical and hippocampal neurons induced by excitotoxic and oxidative insults in cell culture and in vivo. Because neuronal degeneration may be initiated by alterations occurring in synaptic compartments in disorders ranging from Alzheimer's disease to stroke, we tested the hypothesis that neurotrophic factors can exert direct protective actions at the level of the synapse. We now report that a nine amino acid bioactive fragment of activity-dependent neurotrophic factor (ADNF-9) enhances basal glucose and glutamate transport, and attenuates oxidative impairment of glucose and glutamate transport induced by amyloid beta-peptide and Fe(2+), in neocortical synaptosomes. Preservation of transporter function required only short-term (1-2 h) pretreatments. Basic fibroblast growth factor (bFGF) was also effective in suppressing oxidative impairment of synaptic transporter functions, while nerve growth factor (NGF) was less effective. Additional analyses showed that ADNF-9, bFGF and NGF suppress oxidative stress and mitochondrial dysfunction induced by amyloid beta-peptide and Fe(2+) in synaptosomes. Our data suggest that ADNF-9 can act locally in synaptic compartments to suppress oxidative stress and preserve function of glucose and glutamate transporters. Such synapto-protective actions suggest roles for activity-dependent trophic signaling in preventing degeneration of neuronal circuits, and indicate possible therapeutic applications of agents that stimulate local synaptic (transcription-independent) neurotrophic factor signaling pathways.
Guo
Z H
ZH
Sanders-Brown Research Center on Aging and Department of Anatomy & Neurobiology, University of Kentucky, Lexington, KY 40536, USA.
Mattson
M P
MP
D000682:Amyloid / Q000378:metabolism* / Q000494:pharmacology; D016229:Amyloid beta-Peptides / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D002540:Cerebral Cortex / Q000378:metabolism*; D004705:Endocytosis / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005296:Ferrous Compounds / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism / Q000494:pharmacology; D005456:Fluorescent Dyes; D005947:Glucose / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D066298:In Vitro Techniques; D018942:Macrolides; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D020932:Nerve Growth Factor / Q000378:metabolism / Q000494:pharmacology; D009414:Nerve Growth Factors / Q000378:metabolism / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000378:metabolism / Q000494:pharmacology; D018696:Neuroprotective Agents / Q000378:metabolism / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D010446:Peptide Fragments / Q000378:metabolism / Q000494:pharmacology; D017729:Presynaptic Terminals / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism
D000682:Amyloid; D016229:Amyloid beta-Peptides; D000900:Anti-Bacterial Agents; D004791:Enzyme Inhibitors; D005296:Ferrous Compounds; D005456:Fluorescent Dyes; D018942:Macrolides; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D010446:Peptide Fragments; C113041:amyloid beta-protein (35-25); D016222:Fibroblast Growth Factor 2; C020748:ferrous sulfate; D018698:Glutamic Acid; C040929:bafilomycin A1; D020932:Nerve Growth Factor; D005947:Glucose