Inhibition of Aβ42 aggregation using peptides selected from combinatorial libraries

Abstract

Increasing evidence suggests that the aggregation of the small peptide Aβ42 plays an important role in the development of Alzheimer's disease. Inhibiting the initial aggregation of Aβ42 may be an effective treatment for preventing, or slowing, the onset of the disease. Using an in vivo screen based on the enzyme EGFP, we have searched through two combinatorially diverse peptide libraries to identify peptides capable of inhibiting Aβ42 aggregation. From this initial screen, three candidate peptides were selected and characterized. ThT studies indicated that the selected peptides were capable of inhibiting amyloid aggregation. Additional ThT studies showed that one of the selected peptides was capable of disaggregating preformed Aβ42 fibers.

Macromolecular and small-molecule modulation of intracellular Aβ42 aggregation and associated toxicity

“…The Aβ 42 -EGFP fusion protein used in the present study does not fluoresce well when expressed in bacteria due to the effect of aggregation on the maturation of the EGFP fluorophore [14]. Inhibitors of aggregation can partially restore fluorescence, however, and this principle has been used in high-throughput screening protocols to identify anti-amyloidogenic molecules [14,22].…”

“…The pCDF-Aβ 42 -EGFP plasmid [14] was a gift from Dr David Moffet (Department of Chemistry and Biochemistry, Loyola Marymount University, Los Angeles, CA, U.S.A.). The Aβ 42 -EGFP sequence was PCR-amplified from pCDF-Aβ 42 -EGFP using the primers 5 -TCAGGTACCGCCACCATGGATGCGG-AATTT-3 and 5 -GTCTCTAGATTACTTGTACAGCTCGTC-CAT-3 , and was cloned into the KpnI and XbaI sites of the mammalian cell expression vector pcDNA3.3-TOPO (Invitrogen), generating pcDNA3-Aβ 42 -EGFP, which was validated by sequencing.…”

Functional Characteristics and Molecular Mechanism of a New scFv Antibody Against Aβ42 Oligomers and Immature Protofibrils

“…These cytotoxic Aβ42 aggregates have been hypothesized to play a causative and central role in AD onset and progression. Potential therapeutic approaches to AD include reducing Aβ42 synthesis by targeting the enzymes that process amyloid precursor protein (APP) to Aβ42 [2][3][4], inhibiting Aβ42 aggregation [5,6], increasing the clearance of Aβ42 from the brain [7,8], decreasing Aβ42 aggregate burden in the brain [8,9], and reducing inflammation associated with Aβ42 deposition [10,11].…”

Identification of Novel Short Peptide Inhibitors of Soluble 37/48 kDa Oligomers of Amyloid β42

“…Several peptides had been reported to inhibit A42 fibrillation: LPFFD, by Soto et al, 21) MQKLDVVAE-DAGSNK, by Baine et al, 22) and KQKLLLFLEE, by Mihara et al, 23) all designed based on the central hydrophobic region (H14-D23) of the A molecule. Among these, LPFFD and KQKLLLFLEE were found not to inhibit soluble 37/48 kDa oligomer formation of A42.…”