Apolipoproteins E3 and E4 induce, and transthyretin prevents accumulation of the Alzheimer's beta-amyloid peptide in cultured vascular smooth muscle cells.

Cultured brain vascular smooth muscle cells (SMCs) accumulate beta-peptide in intracytoplasmic granules [9,10,33]. We show here that apoE3 and E4 induces the intracytoplasmic beta-peptide accumulation in cultured human and canine SMCs. The induction is dose-dependent and the accumulated granules also contain apoE and some were thioflavine S-positive. The deposits induced with apoE3 were more abundant though less stable than with apoE4. Transthyretin at physiological concentrations blocked the effects of apoE3/E4. Thus, accumulation of beta-peptide appears to be regulated by beta-peptide carrier proteins.