Self-assembling peptide RADA16: a promising scaffold for tissue engineering and regenerative medicine

A new design and computational survey on RGD biofunctionalized RADA16-I self-assembling peptide for tissue engineering applications

Tissue engineering constantly needs innovative and biocompatible materials, and peptide-based materials seem very inspiring. Here we developed two new self-assembling peptides based on RADA16-I and RGD peptides and studied their potential in forming nanofibers under various conditions using all-atom and coarse-grained molecular dynamics simulation methods. First, a double-tailed RGD (dtRGD) peptide was designed by attaching two RADA16-I tails to an RGD-containing loop in which two disulfide bonds stabilized the loop integrity. In the second design, we bonded one side of the loop to the DA16-I tail (otRGD). The dtRGD peptides exhibited a remarkable propensity to form beta-sheet structures during all-atom MD simulations, starting from the initial random coil structure. The most promising outcomes in nanofiber formation were observed when simulating these peptides in a salt concentration that mimics the extracellular matrix. The representation of the RGD epitope was also significantly evident under these conditions. In the otRGD design, the final structure displayed a globular-like morphology, predominantly possessing coils and alpha-helices secondary structures, while maintaining effective RGD peptide exposure. This investigation signified the possibility of a new RGD representing biomaterial for tissue engineering purposes, however, further theoretical and experimental investigations are imperative to unlock their capabilities and applications.

Efficacy of RADA16-Based Self-Assembling Peptides on Wound Healing: A Meta-Analysis of Preclinical Animal Studies

Objectives: This analysis aims to provide evidence supporting the feasibility of clinical application of self-assembling peptides for skin wound healing. Methods: This review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Web of Science, and Cochrane Library were searched (up to June 17, 2024). The primary outcome, wound closure rate at 7 and 14 days post-injury, was pooled using a random-effects meta-analysis. The risk of bias (ROB) assessment and meta-analysis were performed using the Systematic Review Centre for Laboratory animal Experimentation (SYRCLE)'s ROB tool for animal studies and RevMan software. Results: A total of 502 unique records were identified from our search, with 12 experimental animal studies meeting the prespecified inclusion criteria (n = 272 animals). The RADA16 interventions promoted wound closure rate compared to controls (saline or no treatment group) in both diabetic and non-diabetic animal models (Mean Difference (MD) = 11.25, 95% Confidence Interval (CI): 5.73 to 16.78, p < 0.0001; MD = 9.48, 95% CI: 4.75 to 14.22, p < 0.0001 at 7 and 14 days post-injury, respectively). Healing was further enhanced using RADA16-based functional self-assembling peptides compared to RADA16 group in both diabetic and non-diabetic animal models (MD = 27.25, 95% CI: 22.68 to 31.83, p < 0.00001; MD = 29.11, 95% CI: 24.30 to 33.91, p < 0.00001 at 7 and 14 days after injury, respectively). The ROB was uncertain for most studies due to insufficient reporting. Conclusions: RADA16-based self-assembling peptides, particularly those modified with functional peptide motifs, represent a promising treatment for non-diabetic and diabetic wounds in pre-clinical studies, and translation to the clinical domain appears warranted.

How Advanced are Self-Assembled Nanomaterials for Targeted Drug Delivery? A Comprehensive Review of the Literature

The development of effective drug delivery systems is a key focus in pharmaceutical research, aiming to enhance therapeutic efficacy while minimizing adverse effects. Self-assembled nanostructures present a promising solution due to their tunable properties, biocompatibility, and ability to encapsulate and deliver therapeutic agents to specific targets. This review examines recent advancements in drug-based self-assembled nanostructures for targeted delivery applications, including drug-drug conjugates, polymeric-based architectures, biomolecules, peptides, DNA, squalene conjugates and amphiphilic drugs. Various strategies for fabricating these nanostructures are discussed, with an emphasis on the design principles and mechanisms underlying their self-assembly and potential for targeted drug delivery to specific tissues or cells. Furthermore, the integration of targeting ligands, stimuli-responsive moieties and imaging agents into these nanostructures is explored for enhanced therapeutic outcomes and real-time monitoring. Challenges such as stability, scalability and regulatory hurdles in translating these nanostructures from bench to bedside are also addressed. Drug-based self-assembled nanostructures represent a promising platform for developing next-generation targeted drug delivery systems with improved therapeutic efficacy and reduced side effects.

The effects of self-assembling peptide on glial cell activation

Glial cells play a critical role in the healthy and diseased phases of the central nervous system (CNS). CNS diseases involve a wide range of pathological conditions characterized by poor recovery of neuronal function. Glial cell-related target therapies are progressively gaining interest in inhibiting secondary injury-related death. Modulation of the extracellular matrix by artificial scaffolds plays a critical role in the behavior of glial cells after injury. Among numerous types of scaffolds, self-assembling peptides (SAPs) notably give attention to the design of a proper biophysical and biomechanical microenvironment for cellular homeostasis and tissue regeneration. Implementing SAPs in an injured brain can induce neural differentiation in transplanted stem cells, reducing inflammation and inhibiting glial scar formation. In this review, we investigate the recent findings to elucidate the pivotal role of SAPs in orchestrating the most pivotal secondary response following CNS injury. Notably, we explore their impact on the activation of glial cells and their modulatory effects on microglial and astrocytic polarization.

A Recombinant Human Collagen and RADA-16 Fusion Protein Promotes Hemostasis and Rapid Wound Healing

In this study, we designed a fusion protein, rhCR, by combining human collagen with the self-assembling peptide RADA-16 using genetic engineering technology. The rhCR protein was successfully expressed in Pichia pastoris. The rhCR can self-assemble into a three-dimensional nanofiber network under physiological conditions. The lyophilized rhCR sponge exhibited high elasticity modulus and stable swelling properties. In vitro experiments confirmed that the rhCR had good biocompatibility and could significantly promote the adhesion, proliferation, and migration of fibroblasts (L929), upregulating the expression of genes such as Vim, Fgf, Vegf, and Tgf-β3 in L929 cells. When applied to a mouse liver hemorrhage model, rhCR hemostatic sponges rapidly formed nanofibers on the ruptured liver surface, activated platelet CD62P, and significantly reduced blood loss and bleeding duration compared to the recombinant human collagen (rhCol) alone. Furthermore, the rhCR application markedly accelerated wound healing in a mouse full-thickness skin defect model, with the wound healing rate in the rhCR group being 2.6 times that of the untreated group and 1.7 times that of the rhCol group on day 6 postinjury. Histological and immunofluorescence analyses revealed that the rhCR promoted collagen deposition and epidermal regeneration and improved the quality of skin tissue repair by stimulating tissue cells to produce cytokines, growth factors, and immune factors through immunological regulation. The rhCR fusion protein combines the advantages of collagen and RADA-16, overcoming the limitations of their separate use in hemostatic and tissue engineering applications. This biomaterial and its design idea hold promise for a variety of regenerative applications.

Neurotrophin peptidomimetics for the treatment of neurodegenerative diseases

Neurotrophins, such as nerve growth factor and brain-derived neurotrophic factor, play an essential role in the survival of neurons. However, incorporating better features can increase their therapeutic efficacy in neurodegenerative diseases (NDs). Peptidomimetics, which mimic these neurotrophins, show potential for treating NDs. This study emphasizes the use of peptidomimetics from neurotrophins for treating NDs and their benefits. By improving bioavailability and stability, these molecules can completely transform the therapy for NDs. This in-depth review guides researchers and pharmaceutical developers, providing insight into the changing field of neurodegenerative medicine.

Application of the Self-Assembling Peptide Hydrogel RADA16 for Hemostasis during Tonsillectomy: A Feasibility Study

Tonsillectomy is a common surgical procedure but carries a high risk of readmission for secondary bleeding and pain. This study evaluated the feasibility and effectiveness of using the hemostatic self-assembling peptide hydrogel RADA16 (PuraBond, 3-D Matrix SAS; Caluire et Cuire, France) to control bleeding from the tonsillectomy wound bed. Readmission/re-operation rates were compared between a prospective case series of 21 primarily adult tonsillectomy patients treated with topical RADA16 and an untreated historical Control group of 164 patients who underwent tonsillectomy by 10 surgeons at a single tertiary hospital in the UK between March 2019 and June 2022. Cumulative readmission rates for any reason were 2-fold elevated in Control subjects (18.9%; n = 31/164 subjects) compared to patients treated intra-operatively with RADA16 hemostatic hydrogel (9.5%; n = 2/21) (p = 0.378). Readmission rates for postoperative bleeding were 3-fold higher in Controls (14.6%; n = 24/164 subjects) than in the RADA16-treated group (4.8%; n = 1/21) (p = 0.317). A similar rate of retreatment for pain was recorded in the Control (4.3%; n = 7/164) and RADA16 (4.8%; n = 1/21) groups (p = 0.999). Two Control subjects (1.2%) required re-operation for recalcitrant bleeding; no RADA16 subject (0.0%) required re-operation for any reason. No device-related adverse events occurred in the RADA16 group. Surgeons were pleased with the easy learning curve and technical feasibility associated with intra-operatively administering RADA16 hemostatic hydrogel. Intra-operative hemostasis using RADA16 peptide hydrogel was straightforward and was associated with a trend of 3-fold lower rates of readmission for postoperative bleeding events than untreated Control subjects.

Injectable self-assembled GDF5-containing dipeptide hydrogels for enhanced tendon repair

Owing to the tissue characteristics of tendons with few blood vessels and cells, the regeneration and repair of injured tendons can present a considerable challenge, which considerably affects the motor function of limbs and leads to serious physical and mental pain, along with an economic burden on patients. Herein, we designed and fabricated a dipeptide hydrogel (DPH) using polypeptides P11-4 and P11-8. This hydrogel exhibited self-assembly characteristics and could be administered in vitro. To endow the hydrogel with differentiation and regeneration abilities, we added different concentrations of growth differentiation factor 5 (GDF5) to form GDF5@DPH. GDF5@DPH promoted the aggregation and differentiation of tendon stem/progenitor cells and promoted the regeneration and repair of tendon cells and collagen fibers in injured areas. In addition, GDF5@DPH inhibited inflammatory reactions in the injured area. Owing to its injectable properties, DPH can jointly inhibit adhesion and scar hyperplasia between tissues caused by endogenous inflammation and exogenous surgery and can provide a favorable internal environment for the regeneration and repair of the injured area. Overall, the GDF5@DPH system exhibits considerable promise as a novel approach to treating tendon injury.