Production of beta-amyloid by primary human foetal mixed brain cell cultures and its modulation by exogenous soluble beta-amyloid.
Previous studies on beta-amyloid production have been carried out using transfected cells and cell lines. We measured the 40 and 42 amino acid forms of beta-amyloid released into the culture medium by primary human foetal mixed brain cell aggregate culture over 3 months. In this model, neurones and supporting cells are maintained in serum-free defined medium. The secretion of significant amounts of beta-amyloid 40 and 42 was observed throughout culture for three separate cultures. Levels of beta-amyloid 40 and 42 closely followed the neuronal content of the cultures as estimated by cellular neurone-specific enolase. Addition of synthetic beta-amyloid 1-40 to the cultures for 1 week at 35 days in vitro resulted in a dose-related reduction in cellular neurone-specific enolase levels. Primary human aggregate brain cell cultures produced multimeric beta-amyloid, as determined by immunoassay. beta-Amyloid-treated cultures released diminishing amounts of multimeric beta-amyloid and contained increasing amounts of intracellular multimeric beta-amyloid with increasing exogenous beta-amyloid. These results suggest that release of multimeric beta-amyloid into the extracellular environment by human primary neurones can be affected by the presence of extracellular beta-amyloid. This has implications for Alzheimer's disease in that beta-amyloid released into the extracellular environment by dead/dying neurones could modulate beta-amyloid release by surrounding neurones, potentially causing amplification of toxicity. Moreover, intracellular beta-amyloid oligomer-dependent neurotoxicity may be a component of neurodegeneration in Alzheimer's disease, and other conditions with increased beta-amyloid synthesis, suggesting anti-amyloid therapies for Alzheimer's disease may have to target intracellular beta-amyloid.
Hayes
G M
GM
Department of Infectious Diseases, St. George's Hospital Medical School, Tooting, SW17 0RE, London, UK. ghayes@sghms.ac.uk
Howlett
D R
DR
Griffin
G E
GE
D016229:Amyloid beta-Peptides / Q000187:drug effects / Q000378:metabolism* / Q000494:pharmacology*; D001921:Brain / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018929:Cell Culture Techniques; D004305:Dose-Response Relationship, Drug; D005333:Fetus; D005904:Glial Fibrillary Acidic Protein / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007118:Immunoassay; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010751:Phosphopyruvate Hydratase / Q000187:drug effects / Q000378:metabolism; D012995:Solubility
D016229:Amyloid beta-Peptides; D005904:Glial Fibrillary Acidic Protein; D010751:Phosphopyruvate Hydratase