Human Recombinant Butyrylcholinesterase Purified from the Milk of Transgenic Goats Interacts with Beta-Amyloid Fibrils and Suppresses Their Formation in vitro

Abstract

Background: In Alzheimer’s disease (AD), brain butyrylcholinesterase (BChE) co-localizes with β-amyloid (Aβ) fibrils. Aims: In vitro testing of the significance of this phenomenon to AD progress. Methods: A thioflavine T (ThT) fluorogenic assay, photo-induced cross-linking and quantifiable electron microscopy served to compare the effect on Aβ fibril formation induced by highly purified recombinant human BChE (rBChE) produced in the milk of transgenic goats with that of serum-derived human BChE. Results: Both proteins at 1:50 and 1:25 ratios to Aβ dose-dependently prolonged the ThT lag time and reduced the apparent rate of Aβ fibril formation compared to Aβ alone. Photo-induced cross-linking tests showed that rBChE prolonged the persistence of amyloid dimers, trimers and tetramers in solution, whereas Aβ alone facilitated precipitation of such multimers from solution. Transmission electron microscopy showed that rBChE at 1:100 to Aβ prevented the formation of larger, over 150-nm-long, Aβ fibrils and reduced fibril branching compared to Aβ alone as quantified by macro programming of Image Pro® Plus software. Conclusion: Our findings demonstrate that rBChE interacts with Aβ fibrils and can attenuate their formation, extension and branching, suggesting further tests of rBChE, with unlimited supply and no associated health risks, as a therapeutic agent for delaying the formation of amyloid toxic oligomers in AD patients.

The Butyrylcholinesterase K Variant Confers Structurally Derived Risks for Alzheimer Pathology♦

“…Aliquots were removed at 0, 4, 7, 8, and 22 h and centrifuged (30 min, 14,000 rpm). Soluble fractions were treated as described previously (43). Thioflavine T and bis-ANS fluorescence measurements and transmission electron microscopy were done as described (25, 43).…”

Review of the Toxicology of Chlorpyrifos With an Emphasis on Human Exposure and Neurodevelopment

“…(p. 136) There is also evidence that BuChE collocalizes with betaamyloid fibrils and neurofibrillary tangles, a neuropathological hallmark of AD (Mateo et al, 2008). Additionally, recombinant BuChE prolongs the persistence of soluble forms of amyloid precursors, thereby reducing their aggregation to form the multimers that are required for amyloid plaque formation, another neuropathological hallmark of AD (Podoly et al, 2008).…”

Pharmacokinetic Strategies for Treatment of Drug Overdose and Addiction

“…An alternative may be insertion of the enzyme gene into another organism designed for high-volume expression of the protein. This has been demonstrated on a model basis in plants (e.g., tomato, tobacco), silk worm larvae [74], and goat mammary gland (with secretion into milk) [75]. …”