A Snake Venom Peptide and Its Derivatives Prevent Aβ42 Aggregation and Eliminate Toxic Aβ42 Aggregates In Vitro

Over a century has passed since Alois Alzheimer first described Alzheimer’s disease (AD), and since then, researchers have made significant strides in understanding its pathology. One key feature of AD is the presence of amyloid-β (Aβ) peptides, which form amyloid plaques, and therefore, it is a primary target for treatment studies. Naturally occurring peptides have garnered attention for their potential pharmacological benefits, particularly in the central nervous system. In this study, nine peptide derivatives of Crotamine, a polypeptide from Crotalus durissus terrificus Rattlesnake venom, as well as one d-enantiomer, were evaluated for their ability to modulate Aβ42 aggregation through various assays such as ThT, QIAD, SPR, and sFIDA. All tested peptides were able to decrease Aβ42 aggregation and eliminate Aβ42 aggregates. Additionally, all of the peptides showed an affinity for Aβ42. This study is the first to describe the potential of crotamine derivative peptides against Aβ42 aggregation and to identify a promising d-peptide that could be used as an effective pharmacological tool against AD in the future.


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Figure S7 MTT assay of CDPs on SH-SY5Y cells.

Figure S10 .
Figure S10.Negatively charged residues in the Aβ structure and surface.

Figure S3 .
Figure S3.Effect of CDP-3, -4, -5 and -7 on Aβ42 aggregation using ThioflavinT assays.The ThT fluorescence signal with only Aβ42 is shown in blue.In orange, the action of CDP-3, -4, -5 and -7 in the signal of ThioflavinT.A: Effect of CDP-3 against Aβ42 aggregation.B: Effect of CDP-4 against Aβ42 aggregation.C: Effect of CDP-5 against Aβ42 aggregation and D: Effect of CDP-7 against Aβ42 aggregation.Data shown are the mean ± SEM from three independent measurements (n = 3).

Figure S4 .
Figure S4.Dose dependency of CDP-1 and CDP-2 against the Aβ42 aggregation.The ThT fluorescence signal with only Aβ42 is shown in blue.In orange, the action of CDP-1 and -2 at different concentrations in the signal of ThioflavinT.Effect CDP-1 (A) and CDP-2 (B) doses (0.5, 1, 3, 6, 13 and 28 μM) on Aβ42 aggregation.Data shown are the mean ± SEM from three independent measurements (n = 3).

Figure
Figure S5.sFIDA with Aβ aggregates in different concentrations.A: TIRM images and B: Pixel count of the Aβ aggregate standard curve.Data shown are the mean ± SEM from three independent measurements (n = 3).Asterisks mean that the data differ from the control significantly at *: p<0.05, **: p<0.01 and ***: p<0.001 levels according to analyses by a two sample t-test.

Figure S6 .
Figure S6.Biacore SPR kinetic analyses of peptides to Aβ42.The sensorgram and saturation curve of the titration are shown.Sensorgrams were obtained by using a different concentration of peptides (Coloured sensorgrams represent different concentrations in µM).Binding curves were fitted to a steady-state affinity model to get KD values.CDP-1 (A, B), CDP-2 (C, D), CDP-6 (E, F) and CDP-8 (G, H).

Figure S7 .
Figure S7.MTT assay of CDPs on SH-SY5Y cells.MTT assay evaluated the cytotoxicity of four L-peptides and one D-peptide, each at a concentration range between 0 to 100 µM.The control shows the cell viability without peptide, and 0.1% Triton x-100 was used as a negative control.A: CDP-1, B: CDP-2, C: CDP-6, D: CDP-8 and E: CDP-1D.Data shown are the means ± SD from three independent measurements (n = 3).Asterisks mean that the data differ from the control significantly at *: p<0.05 and ***: p<0.001 levels according to analyses by two-way ANOVA.

Figure S8 .
Figure S8.MTT assay of CDPs on HEK293 cells.MTT assay evaluated the cytotoxicity of four L-peptides and one D-peptide, each at a concentration range between 0 to 100 µM.The control shows the cell viability without peptide, and 0.1% Triton x-100 was used as a negative control.A: CDP-1, B: CDP-2, C: CDP-6, D: CDP-8 and E: CDP-1D.Data shown are the means ± SD from three independent measurements (n = 3).Asterisks mean that the data differ from the control significantly at *: p<0.05, **: p<0.01 and ***: p<0.001 levels according to analyses by two-way ANOVA.

Figure S10 .
Figure S10.Negatively charged residues in the Aβ structure and surface.Ribbon view and coloumbic surface representation of the Aβ monomer structure (PDB: 2LFM).Residues with negative charges are highlighted as sticks.A: Ribbon and surface view of the Aβ monomer and B: bent forward 45°.C: Sequence of Aβ42, the negatively charged residues are highlighted.