Oxidative stress impairs glutamate uptake in fibroblasts from patients with Alzheimer's disease.
Oxidative stress has been demonstrated in Alzheimer's disease (AD) brain and may affect glutamate transport (GT), thereby leading to excitotoxic neuronal death. Since oxidative stress markers have been shown also in peripheral tissues, we investigated possible GT alterations in fibroblast cultures obtained from 18 patients with AD and 15 control patients and analyzed the effects of the lipoperoxidation product 4-hydroxynonenal (4-HNE) and antioxidants. Basal GT was decreased by 60% in fibroblasts from patients with AD versus control patients. Exposure to HNE did not affect GT in control patients, but it reduced GT by 50% in patients with AD, without any concomitant change in cell viability; conversely, HNE exposure induced a larger increase in ROS intracellular levels in AD than in control fibroblasts. Glutathione and N-acetylcysteine completely blocked 4-HNE effects and also increased basal uptake in AD cells. Moreover, inhibition of glutathione synthesis in control fibroblasts by pretreatment with buthionine sulfoximine resulted in GT reduction (40%) and an increase in ROS levels after exposure to 4-HNE. Nevertheless, since there are no differences between GSH basal level in controls and patients with AD, the alteration of other antioxidant systems cannot be excluded. Our study supports the hypothesis of a systemic impairment of GT in AD, possibly linked to oxidative stress and to reduced antioxidant defenses, which may be partially reversed by antioxidant treatment. Therefore, we suggest fibroblast cultures as a tool for exploring pathogenetic mechanisms and possible therapeutic strategies in patients with AD.
Begni
Barbara
B
Department of Neuroscience and Biomedical Technologies, University of Milano-Bicocca, 20052 Monza, Italy.
Brighina
Laura
L
Sirtori
Elena
E
Fumagalli
Lorenzo
L
Andreoni
Simona
S
Beretta
Simone
S
Oster
Thierry
T
Malaplate-Armand
Catherine
C
Isella
Valeria
V
Appollonio
Ildebrando
I
Ferrarese
Carlo
C
D000111:Acetylcysteine / Q000737:chemistry; D000255:Adenosine Triphosphate / Q000737:chemistry; D000368:Aged; D000369:Aged, 80 and over; D000447:Aldehydes / Q000494:pharmacology; D000544:Alzheimer Disease / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000378:metabolism* / Q000473:pathology; D005609:Free Radicals; D018698:Glutamic Acid / Q000737:chemistry / Q000378:metabolism*; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D015227:Lipid Peroxidation; D008875:Middle Aged; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D013778:Tetrazolium Salts / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D013997:Time Factors
D000447:Aldehydes; D000975:Antioxidants; D005609:Free Radicals; D017382:Reactive Oxygen Species; D013778:Tetrazolium Salts; D013844:Thiazoles; D018698:Glutamic Acid; D000255:Adenosine Triphosphate; D007770:L-Lactate Dehydrogenase; C022616:thiazolyl blue; D005978:Glutathione; C027576:4-hydroxy-2-nonenal; D000111:Acetylcysteine