Search for Fibrous Aggregates Potentially Useful in Regenerative Medicine Formed under Physiological Conditions by Self-Assembling Short Peptides Containing Two Identical Aromatic Amino Acid Residues

The application of the hierarchical approach for the construction of foldameric peptide self-assembled nanostructures

In this paper, we show that a hierarchical approach for the construction of nanofibrils based on α,β-peptide foldamers is a rational method for the design of novel self-assembled nanomaterials based on peptides. Incorporation of a trans-(1S,2S)-2-aminocyclopentanecarboxylic acid residue into the outer positions of the model coiled-coil peptide led to the formation of helical foldamers, which was determined by circular dichroism (CD) and vibrational spectroscopy. The oligomerization state of the obtained peptides in water was established by analytical ultracentrifugation (AUC). The thioflavin T assay and Congo red methods showed that the obtained α,β-peptides possess a strong tendency to aggregate, leading to the formation of self-assembled nanostructures, which were assessed by microscopic techniques. The location of the β-amino acid in the heptad repeat of the coiled-coil structure proved to have an influence on the secondary structure of the obtained peptides and on the morphology of the self-assembled nanostructures.

1,3,5-Triazine Nitrogen Mustards with Different Peptide Group as Innovative Candidates for AChE and BACE1 Inhibitors

A series of new analogs of nitrogen mustards (4a–4h) containing the 1,3,5-triazine ring substituted with dipeptide residue were synthesized and evaluated for the inhibition of both acetylcholinesterase (AChE) and β-secretase (BACE1) enzymes. The AChE inhibitory activity studies were carried out using Ellman’s colorimetric method, and the BACE1 inhibitory activity studies were carried out using fluorescence resonance energy transfer (FRET). All compounds displayed considerable AChE and BACE1 inhibition. The most active against both AChE and BACE1 enzymes were compounds A and 4a, with an inhibitory concentration of AChE IC₅₀ = 0.051 µM; 0.055 µM and BACE1 IC₅₀ = 9.00 µM; 11.09 µM, respectively.

Functionalized Peptide Fibrils as a Scaffold for Active Substances in Wound Healing

Technological developments in the field of biologically active peptide applications in medicine have increased the need for new methods for peptide delivery. The disadvantage of peptides as drugs is their low biological stability. Recently, great attention has been paid to self-assembling peptides that can form fibrils. Such a formulation makes bioactive peptides more resistant to enzymatic degradation and druggable. Peptide fibrils can be carriers for peptides with interesting biological activities. These features open up prospects for using the peptide fibrils as long-acting drugs and are a valid alternative to conventional peptidic therapies. In our study, we designed new peptide scaffolds that are a hybrid of three interconnected amino acid sequences and are: pro-regenerative, cleavable by neutrophilic elastase, and fibril-forming. We intended to obtain peptides that are stable in the wound environment and that, when applied, would release a biologically active sequence. Our studies showed that the designed hybrid peptides show a high tendency toward regular fibril formation and are able to release the pro-regenerative sequence. Cytotoxicity studies showed that all the designed peptides were safe, did not cause cytotoxic effects and revealed a pro-regenerative potential in human fibroblast and keratinocyte cell lines. In vivo experiments in a dorsal skin injury model in mice indicated that two tested peptides moderately promote tissue repair in their free form. Our research proves that peptide fibrils can be a druggable form and a scaffold for active peptides.

Non-Aggregating Amylin Fragments as an Inhibitors of the Aggregation Process of Susceptible to Aggregation Fragments 18-22, 23-27, and 33-37 of Hormone

Amylin aggregation is one of the factors in the development of diabetes mellitus, which is classified as a civilization disease. The aim of this research was to find whether non-aggregating fragments 1-7, 8-12, 13-17 and 28-32 of amylin would inhibit the aggregation of the amyloidogenic cores 18-22, 23-27, 33-37 of hormone. In the study of the inhibitory potential of non-aggregating amylin fragments, a set of independent methods were used to study aggregation properties (spectroscopic and fluorescence studies with the use of indicators, microscopic studies, circular dichroism studies) and the method of prediction of aggregation properties. The performed research allowed to select the cyclic fragment (1-7) H-KCNTATC-OH with disulfide bond as an inhibitor capable of inhibiting the aggregation of all amyloidogenic cores 18-22, 23-27, 33-37 of the hormone. Additionally, it was found that this peptide inhibits insulin hot spot aggregation, which may indicate its universal utility in inhibiting the process of aggregation of hormones regulating carbohydrate metabolism directly related to the development of diabetes. Research on the possibility of the extensive use of the cyclic fragment (1-7) of H-KCNTATC-OH as a peptide inhibitor of the polypeptide/protein aggregation process is ongoing.

Recent Progress in Ionic Coassembly of Cationic Peptides and Anionic Species

Peptide assembly has been extensively exploited as a promising platform for the creation of hierarchical nanostructures and tailor-made bioactive materials. Ionic coassembly of cationic peptides and anionic species is paving the way to provide particularly important contribution to this topic. In this review, the recent progress of ionic coassembly soft materials derived from the electrostatic coupling between cationic peptides and anionic species in aqueous solution is systematically summarized. The presentation of this review starts from a brief background on the general importance and advantages of peptide-based ionic coassembly. After that, diverse combinations of cationic peptides with small anions, macro- and/or oligo-anions, anionic polymers, and inorganic polyoxometalates are described. Emphasis is placed on the hierarchical structures, value-added properties, and applications. The molecular design of cationic peptides and the general principles behind the ionic coassembled structures are discussed. It is summarized that the combination of interesting and unique characteristics that arise both from the chemical diversity of peptides and the wide range of anionic species may contribute in a variety of output, including drug delivery, tissue engineering, gene transfection, and antibacterial activity. The emergent new phenomena and findings are illustrated. Finally, the outlook for the peptide-based ionic coassembly systems is also presented.

Development and application of a 3D periodontal in vitro model for the evaluation of fibrillar biomaterials

Background

Periodontitis is a chronic inflammation of the tooth supporting structures that finally can lead to tooth loss. As chronic periodontitis is associated with systemic diseases multiple approaches have been followed to support regeneration of the destructed tissue. But very few materials are actually used in the clinic. A new and promising group of biomaterials with advantageous biomechanical properties that have the ability to support periodontal regeneration are self-assembling peptides (SAP). However, there is still a lack of 3D periodontal models that can evaluate the migration potential of such novel materials.

Methods

All experiments were performed with primary human periodontal ligament fibroblasts (HPLF). Migration capacity was assessed in a three-dimensional model of the human periodontal ligament by measuring the migration distance of viable cells on coated (Enamel Matrix Protein (EMP), P11–4, collagen I) or uncoated human dentin. Cellular metabolic activity on P11–4 hydrogels was assessed by a metabolic activity assay. Deposition of ECM molecules in a P11–4 hydrogel was visualized by immunostaining of collagen I and III and fibrillin I.

Results

The 3D periodontal model was feasible to show the positive effect of EMP for periodontal regeneration. Subsequently, self-assembling peptide P11–4 was used to evaluate its capacity to support regenerative processes in the 3D periodontal model. HPLF coverage of the dentin surface coated with P11–4 increased significantly over time, even though delayed compared to EMP. Cell viability increased and inclusion of ECM proteins into the biomaterial was shown.

Conclusion

The presented results indicate that the 3D periodontal model is feasible to assess periodontal defect coverage and that P11–4 serves as an efficient supporter of regenerative processes in the periodontal ligament.

Clinical relevance

The establishment of building-block synthetic polymers offers new opportunities for clinical application in dentistry. Self-assembling peptides represent a new generation of biomaterials as they are able to respond dynamically to the changing environment of the biological surrounding. Especially in the context of peri-implant disease prevention and treatment they enable the implementation of new concepts.

Fibrous Aggregates of Short Peptides Containing Two Distinct Aromatic Amino Acid Residues

The aim of the study was the assessment of the ability of short peptides to form aggregates under physiological conditions. The dipeptides studied were derived from different aromatic amino acids (heteroaromatic peptides). Tripeptides were obtained from two distinct aromatic amino acids and cysteine or methionine residue in the C-terminal, N-terminal, or central position. The ability of the peptides to form fibrous aggregates under physiological conditions was evaluated using three independent methods: the Congo Red assay, the Thioflavin T assay, and microscopic examinations using normal and polarized light. Materials potentially useful for regenerative medicine were selected based on their cytotoxicity to the endothelial cell line EA.hy 926 and physicochemical properties of films formed by peptides. The required parameters of biocompatibility were fulfilled by H-PheCysTrp-OH, H-PheCysTyr-OH, H-PheTyrMet-OH, and H-TrpTyr-OH.