Binding and uptake of A beta1-42 by primary human astrocytes in vitro.
Clearance of the amyloid-beta peptide (A beta) as a remedy for Alzheimer's disease (AD) is a major target in on-going clinical trials. In vitro studies confirmed that A beta is taken up by rodent astrocytes, but knowledge on human astrocyte-mediated A beta clearance is sparse. Therefore, by means of flow cytometry and confocal laser scanning microscopy (CLSM), we evaluated the binding and internalization of A beta1-42 by primary human fetal astrocytes and adult astrocytes, isolated from nondemented subjects (n = 8) and AD subjects (n = 6). Furthermore, we analyzed whether alpha1-antichymotrypsin (ACT), which is found in amyloid plaques and can influence A beta fibrillogenesis, affects the A beta uptake by human astrocytes. Upon over night exposure of astrocytes to FAM-labeled A beta1-42 (10 microM) preparations, (80.7 +/- 17.7)% fetal and (52.9 +/- 20.9)% adult A beta-positive astrocytes (P = 0.018) were observed. No significant difference was found in A beta1-42 uptake between AD and non-AD astrocytes, and no influence of ApoE genotype on A beta1-42 uptake was observed in any group. There was no difference in the percentage of A beta-positive cells upon exposure to A beta1-42 (10 microM) combined with ACT (1,000:1, 100:1, and 10:1 molar ratio), versus A beta1-42 alone. CLSM revealed binding of A beta1-42 to the cellular surfaces and cellular internalization of smaller A beta1-42 fragments. Under these conditions, there was no increase in cellular release of the proinflammatory chemokine monocyte-chemoattractant protein 1, as compared with nontreated control astrocytes. Thus, primary human astrocytes derived from different sources can bind and internalize A beta1-42, and fetal astrocytes were more efficient in A beta1-42 uptake than adult astrocytes.
Nielsen
Henrietta M
HM
Department of Clinical Chemistry, Pathology, The Alzheimer Centre, VU University Medical Center Amsterdam, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands. h.nielsen@vumc.nl
Veerhuis
Robert
R
Holmqvist
Bo
B
Janciauskiene
Sabina
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000544:Alzheimer Disease / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D001057:Apolipoproteins E / Q000235:genetics; D001253:Astrocytes / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D010446:Peptide Fragments / Q000378:metabolism*; D011485:Protein Binding; D000514:alpha 1-Antichymotrypsin / Q000378:metabolism
D016229:Amyloid beta-Peptides; D001057:Apolipoproteins E; C111835:CCL2 protein, human; D018932:Chemokine CCL2; D010446:Peptide Fragments; D000514:alpha 1-Antichymotrypsin; C075222:amyloid beta-protein (1-42)