Astrocytes aged in vitro show a decreased neuroprotective capacity.
Alterations in astrocyte function that may affect neuronal viability occur with brain aging. In this study, we evaluate the neuroprotective capacity of astrocytes in an experimental model of in vitro aging. Changes in oxidative stress, glutamate uptake and protein expression were evaluated in rat cortical astrocytes cultured for 10 and 90 days in vitro (DIV). Levels of glial fibrillary acidic protein and S100beta increased at 90 days when cells were positive for the senescence beta-galactosidase marker. In long-term astrocyte cultures, the generation of reactive oxygen species was enhanced and mitochondrial activity decreased. Simultaneously, there was an increase in proteins that stained positively for nitrotyrosine. The expression of Cu/Zn-superoxide dismutase (SOD-1) and haeme oxygenase-1 (HO-1) proteins and inducible nitric oxide synthase (iNOS) increased in aged astrocytes. Glutamate uptake in 90-DIV astrocytes was higher than in 10 DIV ones, and was more vulnerable to inhibition by H2O2 exposure. Enhanced glutamate uptake was probably because of up-regulation of the glutamate/aspartate transporter protein. Aged astrocytes had a reduced ability to maintain neuronal survival. These findings indicate that astrocytes may partially loose their neuroprotective ability during aging. The results also suggest that aged astrocytes may contribute to exacerbating neuronal injury in age-related neurodegenerative processes.
Pertusa
M
M
Department of Pharmacology and Toxicology, Institut d'Investigacions Biomèdiques de Barcelona, CSIC-IDIBAPS, Barcelona, Spain.
García-Matas
S
S
Rodríguez-Farré
E
E
Sanfeliu
C
C
Cristòfol
R
R
D000375:Aging / Q000473:pathology*; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D004305:Dose-Response Relationship, Drug; D027341:Excitatory Amino Acid Transporter 1 / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009414:Nerve Growth Factors / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D000072105:Superoxide Dismutase-1; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
D027341:Excitatory Amino Acid Transporter 1; D005904:Glial Fibrillary Acidic Protein; D009414:Nerve Growth Factors; D017382:Reactive Oxygen Species; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C493392:Slc1a3 protein, rat; C002744:3-nitrotyrosine; D018698:Glutamic Acid; D014443:Tyrosine; D006861:Hydrogen Peroxide; D052247:Nitric Oxide Synthase Type II; D051547:Heme Oxygenase-1; C000606292:Sod1 protein, rat; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1