Laminin blocks the assembly of wild-type Aβ and the Dutch variant peptide into Alzheimer's fibrils

Amyloid fibril formation is believed to be a nucleation-dependent polymerization process which may be influenced by various other factors with important consequences for the development, prevention or treatment of amyloidosis. We have previously shown that laminin inhibits Aβ peptide fibril formation in vitro. Here we present a kinetic study that indicates laminin to be a potent anti-amyloidosis factor, as it not only inhibited Aβ_1-40 fibril aggregation, but also inhibited the aggregation of the Dutch Aβ_1-40 variant, a peptide with a higher capacity to aggregate than the wild-type Aβ_1-40. The inhibitory effect of laminin on amyloid fibril formation was not overcome by the addition of pre-formed Aβ fibrils, suggesting that laminin inhibits the fibril elongation process. At the present time, however, we cannot rule out the possibility that laminin also affects the initial nucleation process of Aβ fibril formation. On other hand, laminin was not able to counteract the amyloid fibril formation promoted by acetylcholinesterase (AChE), another component of the amyloid deposits found in AD brains. The effect of laminin may be important as an inhibitor of Aβ amyloidogenesis in vivo, specifically at the level of cerebral blood vessels.