Dataset Information

Self-assembling multidomain peptide hydrogels accelerate peripheral nerve regeneration after crush injury.

ABSTRACT: Multidomain peptide (MDP) hydrogels are a class of self-assembling materials that have been shown to elicit beneficial responses for soft tissue regeneration. However, their capacity to promote nervous system regeneration remains unknown. The peripheral nervous system (PNS) substantially recovers after injury, partly due to the abundance of extracellular matrix (ECM) components in its basal lamina. However, severe peripheral nerve injuries that significantly damage the ECM continue to be a major clinical challenge as they occur at a high rate and can be extremely detrimental to patients' quality of life. In this study, a panel of eight MDPs were designed to contain various motifs mimicking extracellular matrix components and growth factors and successfully self-assembled into injectable, nanofibrous hydrogels. Using an in vitro screening system, various lysine based MDPs were found to enhance neurite outgrowth. To test their capacity to promote nerve regeneration in vivo, rat sciatic nerve crush injury was performed with MDP hydrogels injected directly into the injury sites. MDP hydrogels were found to enhance macrophage recruitment to the injury site and degrade efficiently over time. Rats that were injected with the MDP hydrogel K₂ and laminin motif-containing MDPs K₂-IIKDI and K₂-IKVAV were found to have significantly accelerated functional recovery and remyelination compared to those injected with HBSS or other MDPs. These results demonstrate that MDPs enhance neurite outgrowth and promote a multicellular pro-regenerative response in peripheral nerve injury. This study provides important insights into the potential of MDPs as biomaterials for nerve regeneration and other clinical applications.

SUBMITTER: Lopez-Silva TL

PROVIDER: S-EPMC7669633 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:The regenerative capacity of the peripheral nervous system is closely related to the role that Schwann cells (SCs) play in construction of the basement membrane containing multiple extracellular matrix proteins and secretion of neurotrophic factors, including laminin (LN) and brain-derived neurotrophic factor (BDNF). Here, we developed a self-assembling peptide (SAP) nanofiber hydrogel based on self-assembling backbone Ac-(RADA)4-NH2 (RAD) dual-functionalized with laminin-derived motif IKVAV (IKV) and a BDNF-mimetic peptide epitope RGIDKRHWNSQ (RGI) for peripheral nerve regeneration, with the hydrogel providing a three-dimensional (3D) microenvironment for SCs and neurites. Methods: Circular dichroism (CD), atomic force microscopy (AFM), and scanning electron microscopy (SEM) were used to characterize the secondary structures, microscopic structures, and morphologies of self-assembling nanofiber hydrogels. Then the SC adhesion, myelination and neurotrophin secretion were evaluated on the hydrogels. Finally, the SAP hydrogels were injected into hollow chitosan tubes to bridge a 10-mm-long sciatic nerve defect in rats, and in vivo gene expression at 1 week, axonal regeneration, target muscular re-innervation, and functional recovery at 12 weeks were assessed. Results: The bioactive peptide motifs were covalently linked to the C-terminal of the self-assembling peptide and the functionalized peptides could form well-defined nanofibrous hydrogels capable of providing a 3D microenvironment similar to native extracellular matrix. SCs displayed improved cell adhesion on hydrogels with both IKV and RGI, accompanied by increased cell spreading and elongation relative to other groups. RSCs cultured on hydrogels with IKV and RGI showed enhanced gene expression of NGF, BDNF, CNTF, PMP22 and NRP2, and decreased gene expression of NCAM compared with those cultured on other three groups after a 7-day incubation. Additionally, the secretion of NGF, BDNF, and CNTF of RSCs was significantly improved on dual-functionalized peptide hydrogels after 3 days. At 1 week after implantation, the expressions of neurotrophin and myelin-related genes in the nerve grafts in SAP and Autograft groups were higher than that in Hollow group, and the expression of S100 in groups containing both IKV and RGI was significantly higher than that in groups containing either IKV or RGI hydrogels, suggesting enhanced SC proliferation. The morphometric parameters of the regenerated nerves, their electrophysiological performance, the innervated muscle weight and remodeling of muscle fibers, and motor function showed that RAD/IKV/RGI and RAD/IKV-GG-RGI hydrogels could markedly improve axonal regeneration with enhanced re-myelination and motor functional recovery through the synergetic effect of IKV and RGI functional motifs. Conclusions: We found that the dual-functionalized SAP hydrogels promoted RSC adhesion, myelination, and neurotrophin secretion in vitro and successfully bridged a 10-mm gap representing a sciatic nerve defect in rats in vivo. The results demonstrated the synergistic effect of IKVAV and RGI on axonal regrowth and function recovery after peripheral nerve injury.

Project description:Here we report three new nanofibrous, self-assembling multidomain peptide (MDP) sequences and examine the effect of sequence on the morphology and expansion of encapsulated Stem cells from Human Exfoliated Deciduous teeth (SHED). We modified our previously reported set of serine-based MDPs, changing the serine residues in the amphiphilic region to threonine. The three new threonine-based sequences self-assemble into antiparallel ?-sheet nanofibers, confirmed by CD and IR. AFM and negative-stained TEM show that the nanofibers formed by the new sequences are more curved than their serine-containing predecessors. Despite this change in nanofiber morphology, SEM illustrates that all three new sequences still form porous hydrogels. K(TL)2SLRG(TL)3KGRGDS, with a designed cleavage site, is able to be degraded by Matrix Metalloprotease 2. We then examine SHED cell response to these new sequences as well as their serine-based predecessors. We observe faster cell attachment and spreading in hydrogels formed by K2(SL)6K2GRGDS and K(SL)3RG(SL)3KGRGDS. By day 3, the SHEDs in all of the serine-based sequences exhibit a fibroblast-like morphology. Additionally, the SHED cells expand more rapidly in the serine-based gels while the cell number remains relatively constant in the threonine-based peptides. In hydrogels formed by K2(TL)6K2GRGDS and K(TL)2SLRG(TL)3KGRGDS, this low expansion rate is accompanied by changes in morphology where SHEDs exhibit a stellate morphology after 3 days in culture; however, by day 7 they appear more fibroblast-shaped. Throughout the duration of the experiment, the SHED cells encapsulated in the K2(TL)6K2 hydrogels remain rounded. These results suggest that the basic MDP structure easily accommodates modifications in sequence and, for SHED cells, the threonine-containing gels require the integrin-binding RGDS sequence for cell attachment to occur, while the serine-based gels are less selective and support an increase in cell number, regardless of the presence or absence of RGDS.

Project description:Multidomain peptides (MDPs) are a class of self-assembling peptides that are organized in a β-sheet motif, resulting in a nanofibrous architecture. This structure is stabilized by hydrophobic packing in the fiber core and a hydrogen-bonding network down the fiber long axis. Under easily controllable conditions, regulated by electrostatic interactions between the peptides and the pH and salt composition of the solvent, the nanofiber length can be dramatically extended, resulting in fiber entanglement and hydrogel formation. One of the chief strengths of this supramolecular material is that the design criteria governing its structure and assembly are robust and permit a wide range of modifications without disruption. This allows the MDPs to be tailored to suit a wide range of applications, particularly in biomedical engineering. For example, delivery of small molecules, proteins, and cells is easily achievable. These materials can be trapped within the matrices of the hydrogel or trapped within the hydrophobic core of the nanofiber, depending on the cargo and the design of the MDP. Interactions between the nanofibers and their cargo can be tailored to alter the release profile, and in the most sophisticated cases, different cargos can be released in a cascading time-dependent fashion. The MDP hydrogel and its cargo can be targeted to specific locations, as the thixotropic nature of the hydrogel allows it to be easily aspirated into a syringe and then delivered from a narrow-bore needle. The sequence of amino acids making up the MDP can also be modified to permit cross-linking or enzymatic degradation. Selection of sequences with or without these modifications allows one to control the rate of degradation in vivo from as rapidly as 1 week to well over 6 weeks as the MDP nanofibers are degraded to their amino acid components. MDP sequences can also be modified to add biomimetic sequences derived from growth factors and other signaling proteins. These chemical signals are displayed at a very high density on the fibers' surface, where they contribute to the modification of cellular behavior. We have used this approach to drive blood vessel formation, which is critical for tissue regeneration generally and more specifically for the treatment of diseases related to poor blood flow. MDPs represent an ideal case of bottom-up design where control of chemical structure leads to control of self-assembly and nanostructure and thereby control of material properties that collectively can control biological function.

Dataset Information

Self-assembling multidomain peptide hydrogels accelerate peripheral nerve regeneration after crush injury.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets