Peptide Probes with Aromatic Residues Tyr and Phe at the X Position Show High Specificity for Targeting Denatured Collagen in Tissues

Extracellular matrix in vascular homeostasis and disease

The extracellular matrix is an essential component and constitutes a dynamic microenvironment of the vessel wall with an indispensable role in vascular homeostasis and disease. From early development through to ageing, the vascular extracellular matrix undergoes various biochemical and biomechanical alterations in response to diverse environmental cues and exerts precise regulatory control over vessel remodelling. Advances in novel technologies that enable the comprehensive evaluation of extracellular matrix components and cell-matrix interactions have led to the emergence of therapeutic strategies that specifically target this fine-tuned network. In this Review, we explore various aspects of extracellular matrix biology in vascular development, disorders and ageing, emphasizing the effect of the extracellular matrix on disease initiation and progression. Additionally, we provide an overview of the potential therapeutic implications of targeting the extracellular matrix microenvironment in vascular diseases.

A Highly Specific and Versatile Biochip for Ultra-Sensitive Quantification of Denatured Collagen in Assessing Collagen Quality

Collagen, a widely used biomaterial, is susceptible to denaturation during production from native tissues, posing serious challenges for its applications in tissue engineering. Accurate quantification of denatured collagen (DC) is essential for evaluating the quality of collagen-based biomaterials, yet quantitative methods for assessing collagen denaturation are lacking. Here, we for the first time present a highly specific biochip for sensitive quantification of denatured collagen levels (Ldc), addressing this critical need in collagen quality analysis. The denatured collagen-specific chip (DCSC) features an intrinsically nontrimerizing peptide probe, F-GOP-14, targeting denatured collagen and a fully denatured collagen-coated capture surface. The DCSC demonstrates exceptional sensitivity and accuracy in quantifying DC concentration (Cdc) and total collagen concentration (Ctc), enabling precise calculation of Ldc. Importantly, DCSC is versatile, detecting Ldc across various denaturing scenarios, including UV radiation, thermal environments, and decellularization. This denatured collagen-specific biochip offers a robust method for accurately analyzing Ldc, with significant potential for enhancing collagen quality assessment in biomaterial development and production.

Type 1 collagen: Synthesis, structure and key functions in bone mineralization

Collagen is a highly abundant protein in the extracellular matrix of humans and mammals, and it plays a critical role in maintaining the body's structural integrity. Type I collagen is the most prevalent collagen type and is essential for the structural integrity of various tissues. It is present in nearly all connective tissues and is the main constituent of the interstitial matrix. Mutations that affect collagen fiber formation, structure, and function can result in various bone pathologies, underscoring the significance of collagen in sustaining healthy bone tissue. Studies on type 1 collagen have revealed that mutations in its encoding gene can lead to diverse bone diseases, such as osteogenesis imperfecta, a disorder characterized by fragile bones that are susceptible to fractures. Knowledge of collagen's molecular structure, synthesis, assembly, and breakdown is vital for comprehending embryonic and foetal development and several aspects of human physiology. In this review, we summarize the structure, molecular biology of type 1 collagen, its biomineralization and pathologies affecting bone.

A fluorescent sensing platform based on collagen peptides-protected Au/Ag nanoclusters and WS2 for determining collagen triple helix integrity

The unique triple helix structure of collagen plays an important role in its biological properties, and the triple helix integrity is closely correlated with its molecular behavior and biological functions. Nevertheless, there is still a lack of convenient, accurate and practical methods for quantitatively determining collagen triple helix integrity. Herein, we first prepared bovine skin collagen peptide (BSCP)-protected Au/Ag nanoclusters (Au/AgNCs@BSCP) with excellent optical properties, high stability and good biocompatibility, which could adsorb on WS₂ surface leading to fluorescence quenching. Upon the addition of collagen, the interaction of collagen and Au/AgNCs@BSCP led to the detachment of Au/AgNCs@BSCP from the WS₂ surface, causing an increase in the fluorescence signal. Using the difference in the fluorescence recovery of the different samples, we achieved the quantitative determination of collagen triple helix integrity. This developed strategy exhibited excellent accuracy, selectivity, and practicality, thus showing promising potentials in biomedical applications.

Non-denatured yak type I collagen accelerates sunburned skin healing by stimulating and replenishing dermal collagen

Sunburn is one of the most common skin lesions caused by excessive UV exposure, and its incidence is highly correlated with the risks of skin cancer. A variety of drugs including corticosteroids and NSAIDs have been developed to treat acute sunburn, however, they have raised severe concerns such as poor healing efficacy and long recovery time. We have for the first time extracted non-denatured type I collagen from yak hide, which displays a canonical triple helical structure with melting temperature of 42.7 °C. The highly pure yak collagen type I (YCI) self-assembles to form well-ordered nanofibers with periodic d-bands. YCI is highly biocompatible, and it significantly promotes the proliferation and adhesion of HFF-1 cells. The sunburn healing effects of YCI has been investigated using acute skin injury mouse model. Histological analysis shows that 4 days' treatment of YCI has resulted in the recovery of sunburned mice skin to a healthy state, indicated by pronounced acceleration of epithelization and collagen deposition. The collagen volume fraction as well as the hydroxyproline (Hyp) content of YCI-treated sunburned skin have been found to be greatly increased, confirming the enhanced regeneration of collagen. YCI creams and dressings have also shown superior healing capacity of sunburn by remarkably shortening the recovery time. Notably, the denatured collagen-targeted staining results indicated a large quantity of denatured collagen in sunburned mice, which became substantially reduced after the YCI treatment. FITC-labeled YCI has been further found to penetrate into the dermis of sunburned mice. The highly biocompatible and bioactive non-denatured YCI provides an improved treatment of sunburn, indicating very promising applications of YCI in cosmetics and dermatology.

Extracellular matrix: paving the way to the newest trends in atherosclerosis

PURPOSE OF REVIEW

The extracellular matrix (ECM) is critical for all aspects of vascular pathobiology. In vascular disease the balance of its structural components is shifted. In atherosclerotic plaques there is in fact a dynamic battle between stabilizing and proinflammatory responses. This review explores the most recent strides that have been made to detail the active role of the ECM - and its main binding partners - in driving atherosclerotic plaque development and destabilization.

RECENT FINDINGS

Proteoglycans-glycosaminoglycans (PGs-GAGs) synthesis and remodelling, as well as elastin synthesis, cross-linking, degradation and its elastokines potentially affect disease progression, providing multiple steps for potential therapeutic intervention and diagnostic targeted imaging. Of note, GAGs biosynthetic enzymes modulate the phenotype of vascular resident and infiltrating cells. In addition, while plaque collagen structure exerts very palpable effects on its immediate surroundings, a new role for collagen is also emerging on a more systemic level as a biomarker for cardiovascular disease as well as a target for selective drug-delivery.

SUMMARY

The importance of studying the ECM in atherosclerosis is more and more acknowledged and various systems are being developed to visualize, target and mimic it.

Interaction mechanism of collagen peptides with four phenolic compounds in the ethanol-water solution

This study demonstrated the interaction mechanism of collagen peptides (CPs) with 4-ethylphenol (4-EP), phenol, guaiacol, and 4-ethylguaiacol (4-EG) in the ethanol-water solution. The ultraviolet visible spectroscopy, zeta potential tests and hydrogen nuclear magnetic spectroscopy manifested that CPs interacted with the phenolic compounds. Meanwhile, Isothermal titration calorimetry determination indicated that the CPs was hydrogen bonded with 4-EP in 52 %(v/v) ethanol-water solution, while the hydrophobic forces played a major role in the interaction of CPs with guaiacol and 4-EG, respectively. Moreover, hydrogen and hydrophobic bonds were involved in the interaction between CPs and phenol. Finally, Head Space-solid Phase Microextraction Gas Chromatography Mass Spectrometry analysis indicated that the content of phenolic compounds in model solution efficiently decreased with the presence of CPs. In the real liquor, it was found that the content of volatile compounds (including phenolic compounds) was obviously decreased after CPs added.

Universal colorful staining of cancer tissues and normal tissues for histological diagnosis

The versatility of multicolor imaging of human tissues based on staining with perylene monoimide-mannose conjugates PMI-Man and co-staining with PMI-Man and eosin (P&E) was investigated for human cancer and normal tissues. Staining with PMI-Man or co-staining with PMI-Man and eosin showed a perfect histological morphology both in confocal fluorescence microscopy and light microscopy. This approach provided a universal colorful staining method for cancer tissues and normal tissues.