Pathologic Amyloid β‐Protein Cell Surface Fibril Assembly on Cultured Human Cerebrovascular Smooth Muscle Cells

• Published in: Journal of neurochemistry 1998-01, Vol.70 (1), p.216-223
• Main Authors: Van Nostrand, William E., Melchor, Jerry P., Ruffini, Lynda
• Format: Article
• Language: English
• Subjects: Alzheimer's disease; Amyloid beta-Peptides - drug effects; Amyloid beta-Peptides - genetics; Amyloid beta-Peptides - physiology; Amyloidosis - complications; Amyloidosis - genetics; Biological and medical sciences; Cell Membrane - metabolism; Cells, Cultured; Cerebral amyloid angiopathy; Cerebral Hemorrhage - complications; Cerebral Hemorrhage - genetics; Cerebrovascular Circulation - physiology; Circular Dichroism; Coloring Agents - pharmacology; Congo Red - pharmacology; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Dutch type; Fluorescent Dyes; Hereditary cerebral hemorrhage with amyloidosis; Humans; Immunoblotting; Medical sciences; Microscopy, Electron; Muscle, Smooth, Vascular - cytology; Muscle, Smooth, Vascular - metabolism; Muscle, Smooth, Vascular - physiology; Mutation; Neurology; Peptide Fragments - drug effects; Peptide Fragments - genetics; Peptide Fragments - physiology; Thiazoles - metabolism
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1046/j.1471-4159.1998.70010216.x

: Cerebrovascular amyloid β‐protein (Aβ) deposition is a key pathological feature of Alzheimer's disease and hereditary cerebral hemorrhage with amyloidosis‐Dutch type (HCHWA‐D). Aβ1–40 containing the E22Q HCHWA‐D mutation, but not wild‐type Aβ1–40, potently induces several pathologic responses in cultured human cerebrovascular smooth muscle cells, including cellular degeneration and a robust increase in the levels of cellular Aβ precursor. In the present study, we show by several quantitative criteria, including thioflavin T fluorescence binding, circular dichroism spectroscopy, and transmission electron microscopic analysis, that at a concentration of 25 µM neither HCHWA‐D Aβ1–40 nor wild‐type Aβ1–40 appreciably assembles into β‐pleated sheet‐containing fibrils in solution over a 6‐day incubation period. In contrast, at the same concentrations, HCHWA‐D Aβ1–40, but not wild‐type Aβ1–40, selectively binds and assembles into abundant fibrils on the surfaces of cultured human cerebrovascular smooth muscle cells. The simultaneous addition of an equimolar concentration of the dye Congo red prevents the cell surface fibril assembly of HCHWA‐D Aβ1–40. Moreover, Congo red effectively blocks the key pathologic responses induced by HCHWA‐D Aβ1–40 in these cells. The present findings suggest that the surface of human cerebrovascular smooth muscle cells may selectively orchestrate the assembly of pathogenic Aβ fibrils and that cell surface Aβ fibril formation plays an important role in causing the pathologic responses in these cells.