Matrix-Bound VEGF Mimetic Peptides: Design and Endothelial-Cell Activation in Collagen Scaffolds

Chan, Tania R.; Stahl, Patrick J.; Yu, S. Michael

doi:10.1002/adfm.201101163

Cited by 75 publications

(93 citation statements)

References 56 publications

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“…The density of photo-induced CMP binding to intact collagen was determined to be as high as 0.56 AE 0.03 nmol∕cm 2 , which is well above the bioactive ligand density for a variety of cell scaffold interactions in cell culture and tissue development (20,21). Using CF NB ðGPOÞ 9 , we were also able to photo-pattern collagen and gelatin films demonstrating the potential for local immobilization of CMP conjugated bioactive components (10,22,23) to collagen-containing tissue engineering scaffolds (Fig. 2D) (24,25).…”

Section: Resultsmentioning

confidence: 90%

Targeting collagen strands by photo-triggered triple-helix hybridization

Foss

Summerfield

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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167

244

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Collagen remodeling is an integral part of tissue development, maintenance, and regeneration, but excessive remodeling is associated with various pathologic conditions. The ability to target collagens undergoing remodeling could lead to new diagnostics and therapeutics as well as applications in regenerative medicine; however, such collagens are often degraded and denatured, making them difficult to target with conventional approaches. Here, we present caged collagen mimetic peptides (CMPs) that can be phototriggered to fold into triple helix and bind to collagens denatured by heat or by matrix metalloproteinase (MMP) digestion. Peptidebinding assays indicate that the binding is primarily driven by stereo-selective triple-helical hybridization between monomeric CMPs of high triple-helical propensity and denatured collagen strands. Photo-triggered hybridization allows specific staining of collagen chains in protein gels as well as photo-patterning of collagen and gelatin substrates. In vivo experiments demonstrate that systemically delivered CMPs can bind to collagens in bones, as well as prominently in articular cartilages and tumors characterized by high MMP activity. We further show that CMP-based probes can detect abnormal bone growth activity in a mouse model of Marfan syndrome. This is an entirely new way to target the microenvironment of abnormal tissues and could lead to new opportunities for management of numerous pathologic conditions associated with collagen remodeling and high MMP activity.A s the most abundant protein in mammals, collagens play a crucial role in tissue development and regeneration, and their structural or metabolic abnormalities are associated with debilitating genetic diseases and various pathologic conditions. Although collagen remodeling occurs during development and normal tissue maintenance, particularly for renewing tissues (e.g., bones), excess remodeling activity is commonly seen in tumors, arthritis, and many other chronic wounds. During collagen remodeling, large portions of collagens are degraded and denatured by proteolytic enzymes, which can be explored for diagnostic and therapeutic purposes. Since unstructured proteins are not ideal targets for rational drug design, library approaches have been employed to develop monoclonal antibody (1, 2) and peptide probes (3) that specifically bind to cryptic sites in collagen strands that become exposed when denatured. However, these probes suffer from poor pharmacokinetics (4), and/or low specificity, and binding affinity (5).We envisioned that triple helix, the hallmark structural feature of collagen, could provide a unique targeting mechanism for the denatured collagens. The triple helix is nearly exclusively seen in collagens except as small subdomains in a few noncollagen proteins (6). Considering its striking structural similarity to the DNA double helix in terms of multiplex formation by periodic interchain hydrogen bonds along the polymer backbone (6), we thought that a small peptide sequence with strong triple-helix prope...

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Section: Resultsmentioning

confidence: 90%

Targeting collagen strands by photo-triggered triple-helix hybridization

Foss

Summerfield

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

167

244

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“…28 In soluble form, the QK peptide has been reported to demonstrate angiogenic bioactivity above a threshold concentration of about 1 pM. 6,28,29 The QK peptide has also demonstrated bioactivity across a broad range of concentrations (1 pM-100 mM) when presented as a substrate-bound peptide on collagen scaffolds via collagenbinding peptides, 30 on hydroxyapatite via binding of an osteocalcin sequence, 29 and on self-assembled monolayers via covalent immobilization. 31 Keeping the MITCH network polymers unmodified, affinity immobilization is achieved simply by synthesizing a fusion of QK to a single proline-rich domain (P1), which acts as an affinity tag (Fig.…”

Section: Introductionmentioning

confidence: 96%

Avidity-Controlled Delivery of Angiogenic Peptides from Injectable Molecular-Recognition Hydrogels

Mulyasasmita

Cai

Hori

et al. 2014

Tissue Engineering Part A

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Peptide mimics of growth factors represent an emerging class of therapeutic drugs due to high biological specificity and relative ease of synthesis. However, maintaining efficacious therapeutic dosage at the therapy site has proven challenging owing to poor intestinal permeability and short circulating half-lives in the blood stream. In this work, we present the affinity immobilization and controlled release of QK, a vascular endothelial growth factor (VEGF) mimetic peptide, from an injectable mixing-induced two-component hydrogel (MITCH). The MITCH system is crosslinked by reversible interactions between WW domains and complementary proline-rich peptide modules. Fusion of the QK peptide to either one or two units of the proline-rich sequence creates bifunctional peptide conjugates capable of specific binding to MITCH while preserving their angiogenic bioactivity. Presenting two repeats of the proline-rich sequence increases the binding enthalpy 2.5 times due to avidity effects. Mixing of the drug conjugates with MITCH components results in drug encapsulation and extended release at rates consistent with the affinity immobilization strength. Human umbilical vein endothelial cells (HUVECs) treated with the soluble drug conjugates exhibit morphogenetic events of VEGF receptor 2 signal transduction followed by cell migration and organization into networks characteristic of early angiogenesis. In a three-dimensional model where HUVECs were cultured as spheroids in a matrix of collagen and fibronectin, injection of drug-releasing MITCH resulted in significantly more cell outgrowth than drugs injected in saline. This ability to sustain local drug availability is ideal for therapeutic angiogenesis applications, where spatiotemporal control over drug distribution is a key requirement for clinical success.

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“…Our studies employ collagen-mimetic peptides (CMPs), which comprise primarily a collagen-like (GXY) n motif and have the unique capacity to stably integrate within native collagen through a reversible strand-exchange process [41–49]. Our prior work was the first to demonstrate that CMP-based integration of polyplexes could be used to retain stabilized DNA on collagen with improved control over the timing and extent of gene delivery for periods of a week to over a month (2-fold longer than that of unmodified polyplexes), and the direct correlation of transgene expression with MMP concentrations.…”

Section: Introductionmentioning

confidence: 99%

ECM turnover-stimulated gene delivery through collagen-mimetic peptide-plasmid integration in collagen

2017

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Gene therapies have great potential in regenerative medicine; however, clinical translation has been inhibited by low stability and limited transfection efficiencies. Herein, we incorporate collagen-mimetic peptide (CMP)-linked polyplexes in collagen scaffolds to increase DNA stability by up to 400% and enable tailorable in vivo transgene expression at 100-fold higher levels and 10-fold longer time periods. These improvements were directly linked to a sustained interaction between collagen and polyplexes that persisted during cellular remodeling, polyplex uptake, and intracellular trafficking. Specifically, incorporation of CMPs into polyethylenimine (PEI) polyplexes preserved serum-exposed polyplex-collagen activity over a period of 14 days, with 4 orders-of-magnitude more intact DNA present in CMP-modified polyplex-collagen relative to unmodified polyplex-collagen after a 10 day incubation under cell culture conditions. CMP-modification also altered endocytic uptake, as indicated by gene silencing studies showing a nearly 50% decrease in transgene expression in response to caveolin-1 silencing in modified samples versus only 30% in unmodified samples. Furthermore, cellular internalization studies demonstrated that polyplex-collagen association persisted within cells in CMP polyplexes, but not in unmodified polyplexes, suggesting that CMP linkage to collagen regulates intracellular transport. Moreover, experiments in an in vivo repair model showed that CMP modification enabled tailoring of transgene expression from 4 to 25 days over a range of concentrations. Overall, these findings demonstrate that CMP decoration provides substantial improvements in gene retention, altered release kinetics, improved serum-stability, and improved gene activity in vivo. This versatile technique has great potential for multiple applications in regenerative medicine.

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Matrix-Bound VEGF Mimetic Peptides: Design and Endothelial-Cell Activation in Collagen Scaffolds

Cited by 75 publications

References 56 publications

Targeting collagen strands by photo-triggered triple-helix hybridization

Targeting collagen strands by photo-triggered triple-helix hybridization

Avidity-Controlled Delivery of Angiogenic Peptides from Injectable Molecular-Recognition Hydrogels

ECM turnover-stimulated gene delivery through collagen-mimetic peptide-plasmid integration in collagen

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