A Transparent and Injectable Biomaterial Prepared by Mixing Collagen and Anti-Cancer Platinum Derivatives.

This study presents the synthesis of a cross-linked collagen material, named platinum-containing collagen gel (PCG), which is achieved by simply mixing collagen and derivatives of an anti-cancer platinum complex. The cross-linking reagents are derivatives of cisplatin or transplatin, generated through a ligand exchange with dimethyl sulfoxide. PCG exhibits superior physical strength and transparency compared with the native collagen gel formed through spontaneous fibril formation.

The Thermal Stability of the Collagen Triple Helix Is Tuned According to the Environmental Temperature.

Triple helix formation of procollagen occurs in the endoplasmic reticulum (ER) where the single-stranded α-chains of procollagen undergo extensive post-translational modifications. The modifications include prolyl 4- and 3-hydroxylations, lysyl hydroxylation, and following glycosylations. The modifications, especially prolyl 4-hydroxylation, enhance the thermal stability of the procollagen triple helix.

Synthetic Collagen-like Polymer That Undergoes a Sol-Gel Transition Triggered by Acyl Migration at Physiological pH.

We previously reported an artificial collagen gel that can be used as a cell-culture substrate by end-to-end cross-linking of collagen-like triple-helical peptides via disulfide bonds. However, the gel had to be formed a priori by polymerizing the peptide in an acidic solution containing dimethyl sulfoxide for several days, which prevented its use as an injectable gel or three-dimensional (3D) scaffold for cell culture. In this study, we developed a collagen-like peptide polymer by incorporating an acyl migration-triggered triple helix formation mechanism into a collagen-like peptide, which formed a gel within 10 min.

Spatiotemporal regulation of PEDF signaling by type I collagen remodeling.

Dynamic remodeling of the extracellular matrix affects many cellular processes, either directly or indirectly, through the regulation of soluble ligands; however, the mechanistic details of this process remain largely unknown. Here we propose that type I collagen remodeling regulates the receptor-binding activity of pigment epithelium-derived factor (PEDF), a widely expressed secreted glycoprotein that has multiple important biological functions in tissue and organ homeostasis. We determined the crystal structure of PEDF in complex with a disulfide cross-linked heterotrimeric collagen peptide, in which the α(I) chain segments-each containing the respective PEDF-binding region (residues 930 to 938)-are assembled with an α2α1α1 staggered configuration.

Peptide precursors that acquire denatured collagen-hybridizing ability by O-to-N acyl migration at physiological pH.

Here, we report peptide probes with either single or cyclic double stranded collagen-like sequences that spontaneously acquire collagen-hybridizing ability at physiological pH. These peptides have ester bonds derived from O-acyl isopeptide units that are converted to amide bonds via intramolecular O-to-N acyl migration by a pH shift. The peptides that do not require pre-treatment for disassembly will be useful as prodrugs in theranostic treatments targeting unfolded collagen.

Lowering the culture temperature corrects collagen abnormalities caused by HSP47 gene knockout.

Heat shock protein 47 (HSP47) is an endoplasmic reticulum (ER)-resident molecular chaperone that specifically recognizes triple helical portions of procollagens. The chaperone function of HSP47 is indispensable in mammals, and hsp47-null mice show an embryonic lethal phenotype accompanied by severe abnormalities in collagen-based tissue structures. Two leading hypotheses are currently accepted for the molecular function of HSP47 as a procollagen-specific chaperone.

Structural optimization of cyclic peptides that efficiently detect denatured collagen.

To develop a facile method for detecting denatured collagen, we investigated the structure-activity relationship of cyclic collagen-mimetic peptides (cCMPs). Reported cCMP prototypes tend to self-assemble and they must be disassembled just before use. Introducing charge repulsion and a deformation in the peptide backbone structure enabled cCMPs to detect denatured collagen without a pre-treatment for disassembly.

Development of a collagen-like peptide polymer via end-to-end disulfide cross-linking and its application as a biomaterial.

Collagen is the most abundant protein in the animal kingdom and has a unique triple-helical structure. It not only provides mechanical strength to tissues, but also performs specific biological functions as a multifaceted signaling molecule. Animal-derived collagen is therefore widely used as a biocompatible material in vitro and in vivo.

A Strategy for Discovering Heterochiral Bioactive Peptides by Using the OB2 P Library and SPOTs Method.

d-Amino acid containing peptides are promising as drug lead compounds because of their expected higher stability in vivo. A heterochiral random peptide library called the one-bead-2 -peptide (OB2 P) library, which can display 2 peptide diastereomers per bead, has been developed. Through screening of the OB2 P library and subsequent binding assay among the peptide diastereomers synthesized in parallel by means of the SPOTs method, new heterochiral mimotopes for the anti-β-endorphin monoclonal antibody have been obtained.

Basic Fibroblast Growth Factor Fused with Tandem Collagen-Binding Domains from Collagenase ColG Increases Bone Formation.

Basic fibroblast growth factor 2 (bFGF) accelerates bone formation during fracture healing. Because the efficacy of bFGF decreases rapidly following its diffusion from fracture sites, however, repeated dosing is required to ensure a sustained therapeutic effect. We previously developed a fusion protein comprising bFGF, a polycystic kidney disease domain (PKD; s2b), and collagen-binding domain (CBD; s3) sourced from the class II collagenase, ColH, and reported that the combination of this fusion protein with a collagen-like peptide, poly(Pro-Hyp-Gly), induced mesenchymal cell proliferation and callus formation at fracture sites.

Cyclic Peptides for Efficient Detection of Collagen.

We report here a new class of collagen-binding peptides, cyclic collagen-mimetic peptides (cCMPs), that efficiently hybridize with the triple-helix-forming portions of collagen. cCMPs are composed of two parallel collagen-like (Xaa-Yaa-Gly) strands with both termini tethered by covalent linkages. Enzyme-linked immunosorbent assays and western blotting analysis showed that cCMPs exhibit more potent affinity toward collagen than reported collagen-binding peptides and can specifically detect different collagen polypeptides in a mixture of proteins.

Development of a carboplatin derivative conjugated with a collagen-like triple-helical peptide.

Aim: The development of a platinum anticancer agent that has improved efficacy by efficient delivery to a tumor and that suppresses side effects has been investigated. Arginine-rich triple-helical peptides are promising drug carriers because of their stability in body fluids and cell-penetrating activity.

Results: We synthesized a carboplatin derivative conjugated with an arginine-rich triple-helical peptide.

Expression of Collagenase is Regulated by the VarS/VarA Two-Component Regulatory System in Vibrio alginolyticus.

Vibrio alginolyticus is an opportunistic pathogen in both humans and marine animals. Collagenase encoded by colA is considered to be one of the virulence factors. Expression of colA is regulated by multiple environmental factors, e.

Structure-activity relationships and action mechanisms of collagen-like antimicrobial peptides.

An antimicrobial triple-helical peptide, R3, was previously obtained from a collagen-like combinatorial peptide library. In this research, based on structure-activity relationship studies of R3, a more potent peptide, RR4, with increased positive net charge and charge density relative to R3, was developed. RR4 exhibited antimicrobial activity against both Gram-negative and Gram-positive bacterial strains, including multidrug-resistant strains.

Collagen-like antimicrobial peptides.

Combinatorial library composed of rigid rod-like peptides with a triple-helical scaffold was constructed. The component peptides were designed to have various combinations of basic and neutral (or hydrophobic) amino acid residues based on collagen-like (Gly-Pro-Yaa)-repeating sequences, inspired from the basic and amphiphilic nature of naturally occurring antimicrobial peptides. Screening of the peptide pools resulted in identification of antimicrobial peptides.

Fecal Excretion of Orally Administered Collagen-Like Peptides in Rats: Contribution of the Triple-Helical Conformation to Their Stability.

Orally ingested peptides are generally digested in the gastrointestinal (GI) tract and absorbed in the form of oligopeptides. We previously reported that intravenously administered collagen-like triple-helical peptides circulated in the bloodstream and were excreted in their intact forms in urine nearly quantitatively. In the present study, we investigated the fates of orally administered collagen-like peptides in rats.

Cellular Uptake of IgG Using Collagen-Like Cell-Penetrating Peptides.

Cell-penetrating peptides (CPPs) are attractive tools for delivering macromolecules that have poor membrane permeability, such as antibodies, into cells. However, the major drawback of conventional CPPs is their instability in bodily fluids. We previously reported a novel CPP employing a collagen-like triple-helical structure that exhibited remarkable resistance against serum proteases.

A cisplatin derivative that inhibits collagen fibril-formation in vitro.

Using an in vitro random screening of small-molecule compounds, we discovered cis-diamminedichloroplatinum(II) (cisplatin), an anticancer agent, as a potential inhibitor of collagen fibril-formation. The inhibitory effect was found only when cisplatin was dissolved in dimethylsulphoxide (DMSO), indicating that the active species were cisplatin derivatives formed in the DMSO solution. The cisplatin derivatives inhibited the formation of collagen fibrils in vitro without affecting the triple-helical conformation of the collagen molecules.

Potential of collagen-like triple helical peptides as drug carriers: Their in vivo distribution, metabolism, and excretion profiles in rodents.

Collagen-model peptides composed of (X-Y-Gly)n sequences were used to study the triple helical structure of collagen. We report the stability of these collagen-like peptides in biological fluids, and their pharmacokinetics including distribution, metabolism, and excretion in animals. A typical collagen-model peptide, H-(Pro-Hyp-Gly)10-OH, was found to be extremely stable in the plasma and distributed mainly in the vascular blood space, and was eliminated through glomerular filtration in the kidneys.

[Collagen-like triple helical peptides: applications in drug development and regenerative medicine].

Collagen family proteins are the predominant components of extracellular matrices existing in all multicellular animals. They provide mechanical strength to tissues, and maintain structural integrity of organs. Also, collagens regulate various biological events, including cell attachment, migration, tissue regeneration and animal development.

NMR and mutational identification of the collagen-binding site of the chaperone Hsp47.

Heat shock protein 47 (Hsp47) acts as a client-specific chaperone for collagen and plays a vital role in collagen maturation and the consequent embryonic development. In addition, this protein can be a potential target for the treatment of fibrosis. Despite its physiological and pathological importance, little is currently known about the collagen-binding mode of Hsp47 from a structural aspect.

Bacterial collagen-binding domain targets undertwisted regions of collagen.

Clostridium histolyticum collagenase causes extensive degradation of collagen in connective tissue that results in gas gangrene. The C-terminal collagen-binding domain (CBD) of these enzymes is the minimal segment required to bind to a collagen fibril. CBD binds unidirectionally to the undertwisted C-terminus of triple helical collagen.