Self-Assembled Amyloid Peptides with Arg-Gly-Asp (RGD) Motifs As Scaffolds for Tissue Engineering

Abstract

Self-assembled peptides gain increasing interest as biocompatible and biodegradable scaffolds for tissue engineering. Rationally designed self-assembling building blocks that carry cell adhesion motifs such as Arg-Gly−Asp (RGD) are especially attractive. We have used a combination of theoretical and experimental approaches toward such rational designs, especially focusing on modular designs that consist of a central ultrashort amphiphilic motif derived from the adenovirus fiber shaft. In this study, we rationally designed RGDSGAITIGC, a bifunctional self-assembling amyloid peptide which encompasses cell adhesion and potential cysteine-mediated functionalization properties through the incorporation of an RGD sequence motif and a cysteine residue at the N-and C-terminal end, respectively. We performed replica exchange MD simulations that suggested that the key factor determining cell adhesion is the total solvent accessibility of the RGD motif and also that the Cterminal cysteine is adequately exposed. The designer peptides self-assembled into fibers that are structurally characterized with Transmission Electron Microscopy, Scanning Electron Microscopy and X-ray fiber diffraction. Furthermore, they supported cell adhesion and proliferation of a model cell line. We consider that the current bifunctional properties of the RGDSGAITIGC fibrilforming peptide can be exploited to fabricate novel biomaterials with promising biomedical applications. Such short selfassembling peptides that are amenable to computational design offer open-ended possibilities toward multifunctional tissue engineering scaffolds of the future.

A novel amyloid designable scaffold and potential inhibitor inspired by GAIIG of amyloid beta and the HIV‐1 V3 loop

“…According to 16 μs replica exchange MD simulations and a subsequent computational analysis performed analogously to previous studies , GAIIG self‐assembles into primarily antiparallel off‐register β‐sheets (Fig. S1A,D,G,J and S2A,D) which possess a high degree of order and alignment of peptides (Fig.…”

“…As for the first postulation, in this study, we focused on one such sequence: YATGAIIGNII derived from a V3 loop [41] (without any modifications at the termini). Similar to GAIIG, according to 16 ls replica exchange MD simulations and a subsequent computational analysis, which was performed analogously to previous studies [14,[31][32][33][34][35], the YAT-GAIIGNII peptide self-assembles into primarily antiparallel off-register b-sheets ( Fig. S1C,F,I,L,N and S2C,F,H), which possess a high degree of order and alignment of peptides (Fig.…”

“…In this study, we carried out experimental and computational studies that show that the shorter GAIIG peptide (amidated at the C-terminus) self-assembles into amyloid bsheets. This sequence is common to the amyloid-b (Ab) peptide (residues [29][30][31][32][33] and to HIV gp120 (residues 24-28 in a typical 35-residue long V3 loop), according to the HIV sequence database (https://www. hiv.lanl.gov/).…”

Beyond function: Engineering improved peptides for therapeutic applications

“…Nearly all self‐assembled structures, including those assembled from peptides, are thermodynamically stable compared to unassembled, monomeric structures, and assembly of peptides can also improve other important characteristics, including responsiveness to environmental conditions, selectivity, proteolytic resistance, and sustained activity . Self‐assembly of peptides into ordered nanostructures is important in various therapeutic applications, including antimicrobial activity, tissue grafting, drug delivery, and vaccine design . In addition to modulating assembly conditions to control self‐assembly, the design of the peptide sequence can also be used to tune the assembly of peptide monomers into nanoscale structures.…”

Self‐Assembling Amyloid Sequences as Scaffolds for Material Design: A Case Study of Building Blocks Inspired From the Adenovirus Fiber Protein

“…The scaffold functionality can be further developed by the insertion of a cysteine residue to enable the conjugation of metals and signaling molecules (such as growth factors) through the exposed sulphydryl groups. For the development of this bifunctional peptide, the amyloidogenic GAITIG sequence was kept as the β‐sheet core and the incorporation of the RGD motif and cysteine residue was done in properly selected positions in the peptide's sequence in order to ensure their accessibility . For this, theoretical insight was sought.…”