Osteoarthritis (OA), a degenerative joint disease characterized by chronic pain and stiffness, is the most common cause of disability in older adults. To date, OA lacks curative treatment and medical care is limited to symptom relief particularly through the use of oral nonsteroidal anti-inflammatory drugs (NSAIDs). However, gastrointestinal and cardiovascular adverse effects and only limited benefits in long-term relief of pain are still associated. Moreover, efficiency is in part impeded by rapid clearance of the drugs and by the special physiological environment of the joint impeding deep penetration of drugs. Hence, to overcome those limitations and improve patient outcome, developing new therapeutic approaches based on anti-inflammatory prodrugs with prolonged drug residence time within the joints appears as a promising strategy in OA. We report herein the development of NSAID prodrugs, derived from diclofenac and naproxen, bearing a positively charged quaternary ammonium (QA) to target the negative-fixed charge density in cartilage by the mean of electrostatic interactions. Our charge-based targeted approach aims to extend the residence time of NSAID within the cartilaginous tissues, leading to a potential decrease of side effects and improved efficiency of locally released drugs. Syntheses of various amide and esters prodrugs of diclofenac and naproxen bearing a QA function were performed, including some hypoxia-activated prodrugs. Since most diclofenac derivatives suffered from high instability preventing any further development, we focused on the naproxen derivatives that were relatively stable in PBS buffer over a 24-h period even if three different degradation patterns were observed in murine plasma. A preliminary screening of their in vitro anti-inflammatory efficacy highlighted a correlation between the PGE-2 inhibition and these cleavage patterns. These results support further in vitro and in vivo evaluations of four of these derivatives in OA models.

Glycosaminoglycans (GAGs) are vital polysaccharides that constitute key elements of the extracellular matrix (ECM), particularly within chondroitin sulfate proteoglycans (CSPGs). GAGs exhibit a dual role in neural tissue: they facilitate synaptic plasticity and cellular adhesion, essential for neural function, while posing as barriers to axonal regeneration following injury. Through interactions with diverse proteins, including enzymes, cytokines, and growth factors, GAGs critically influence neural development, repair, and homeostasis. Recent advancements have underscored the therapeutic potential of modulating GAG synthesis, degradation, and receptor interactions to address neuroinflammation, promote neural repair, and counteract inhibitory signals in the injured CNS. Furthermore, combining GAG-targeted therapies with complementary approaches, such as gene therapy or nanoparticle-based delivery systems, holds promise for achieving synergistic effects and enhancing treatment outcomes. This mini-review explores the multifaceted roles of GAGs in neural physiology and pathology, highlighting their emerging potential as therapeutic targets for neurological disorders.

Thoracic aortic aneurysms (TAAs) are a dilation of the aorta that may fatally dissect or rupture. The current clinical management for TAA is continuous monitoring and surgical replacement once the aortic diameter reaches a specified size or rate of growth. Although operative intervention is often successful in preventing fatal outcomes, not all patients will reach surgical criteria before an aortic event, and the surgery carries significant risk with a potential requirement for reoperation. There is a need for patient-specific diagnostic tools and/or novel therapeutics to treat TAA. In this review, we discuss fluid and solute transport through the aortic wall (transmural aortic transport), its potential contributions to TAA progression, and possible applications for diagnosis and treatment. We first discuss the structural organization of the aortic wall with a focus on cellular and extracellular matrix (ECM) changes associated with TAA that may alter transmural transport. We then focus on aortic transmural transport processes defined with biphasic and multiphasic theory. Biphasic theory describes fluid interactions with a porous solid (i.e., the aortic wall), whereas multiphasic theory describes fluid and solute(s) interactions with a porous solid. We summarize experimental and computational methods to quantify transport through the aortic wall. Finally, we discuss how transmural transport may be used to diagnose, monitor, or treat TAA. Further understanding of transmural transport may lead to new insights into TAA pathobiology and future clinical solutions.

This article provides a comprehensive review of current neuroimaging techniques for visualizing and quantifying extracellular matrix (ECM) components and interstitial fluid (ISF) dynamics in cerebrovascular disorders. It examines how alterations in ECM composition and ISF movement patterns correlate with various cerebrovascular pathologies, including ischemic stroke, frontotemporal dementia, cerebral small vessel disease, Alzhheimer's disease, and vascular dementia. The review emphasizes novel imaging markers specific to ECM/ISF alterations and their utility in differentiating various cerebrovascular pathologies. Special attention is given to the clinical applications of these imaging techniques for early disease detection, monitoring progression, and guiding therapeutic interventions.

Each stage of tumor development is intrinsically linked to the tumor microenvironment (TME), wherein the extracellular matrix (ECM) serves as a vital and abundant component in tumor tissues. The ECM is a non-cellular, three-dimensional macromolecular network scaffold that provides structural support to cells, stores bioactive molecules, and mediates signaling pathways through specific binding to cell surface receptors. Moreover, the ECM in tumor tissues plays a crucial role in impeding drug diffusion and resisting apoptosis induced by conventional anti-cancer therapies that primarily target cancer cells. Therefore, directing attentions towards the tumor ECM can facilitate the identification of novel targets and the development of new therapies. This review aims to summarize the composition, structure, remodeling, and function of tumor ECM, its association with drug resistance, and current targeting strategies, with a specific emphasis on nanoparticles (NPs).

Cichlid fishes inhabiting the East African Great Lakes, Victoria, Malawi, and Tanganyika, are textbook examples of parallel evolution, as they have acquired similar traits independently in each of the three lakes during the process of adaptive radiation. In particular, 'hypertrophied lip' has been highlighted as a prominent example of parallel evolution. However, the underlying molecular mechanisms remain poorly understood. In this study, we conducted an integrated comparative analysis between the hypertrophied and normal lips of cichlids across three lakes based on histology, proteomics, and transcriptomics. Histological and proteomic analyses revealed that the hypertrophied lips were characterized by enlargement of the proteoglycan-rich layer, in which versican and periostin proteins were abundant. Transcriptome analysis revealed that the expression of extracellular matrix-related genes, including collagens, glycoproteins, and proteoglycans, was higher in hypertrophied lips, regardless of their phylogenetic relationships. In addition, the genes in Wnt signaling pathway, which is involved in promoting proteoglycan expression, was highly expressed in both the juvenile and adult stages of hypertrophied lips. Our comprehensive analyses showed that hypertrophied lips of the three different phylogenetic origins can be explained by similar proteomic and transcriptomic profiles, which may provide important clues into the molecular mechanisms underlying phenotypic parallelisms in East African cichlids.

Coal worker's pneumoconiosis (CWP) is characterized by chronic inflammation and pulmonary fibrosis. The key factor contributing to the incurability of CWP is the unclear pathogenesis. This study explored the characteristic changes in proteomics and metabolomics of early and advanced CWP patients through proteomics and metabolomics techniques. Proteomics identified proteins that change with the progression of CWP, with significant enrichment in the TGF-β signaling pathway and autoimmune disease pathways. Metabolomics revealed the metabolic characteristics of CWP at different stages. These metabolites mainly include changes in amino acid metabolism, unsaturated fatty acid synthesis, and related metabolites. Integrated analysis found that ABC transporters are a shared pathway among the three groups, and ABCD2 is involved in the ABC transporter pathway. In the subsequent independent sample verification analysis, consistent with proteomics experiments, compared to the CM group, FMOD expression level was upregulated in the NIC group. TFR expression level was consistently downregulated in both the IC and NIC groups. Additionally, ABCD2 increased in the IC group but decreased in the NIC group. In summary, this study revealed the metabolic characteristics of CWP at different stages. These findings may provide valuable insights for the early prediction, diagnosis, and treatment of CWP.

Aortic dissection continues to be responsible for significant morbidity and mortality, although recent advances in medical data assimilation and in experimental and in silico models have improved our understanding of the initiation and progression of the accumulation of blood within the aortic wall. Hence, there remains a pressing necessity for innovative and enhanced models to more accurately characterize the associated pathological changes. Early on, experimental models were employed to uncover mechanisms in aortic dissection, such as hemodynamic changes and alterations in wall microstructure, and to assess the efficacy of medical implants. While experimental models were once the only option available, more recently they are also being used to validate in silico models. Based on an improved understanding of the deteriorated microstructure of the aortic wall, numerous multiscale material models have been proposed in recent decades to study the state of stress in dissected aortas, including the changes associated with damage and failure. Furthermore, when integrated with accessible patient-derived medical data, in silico models prove to be an invaluable tool for identifying correlations between hemodynamics, wall stresses, or thrombus formation in the deteriorated aortic wall. They are also advantageous for model-guided design of medical implants with the aim of evaluating the deployment and migration of implants in patients. Nonetheless, the utility of in silico models depends largely on patient-derived medical data, such as chosen boundary conditions or tissue properties. In this review article, our objective is to provide a thorough summary of medical data elucidating the pathological alterations associated with this disease. Concurrently, we aim to assess experimental models, as well as multiscale material and patient data-informed in silico models, that investigate various aspects of aortic dissection. In conclusion, we present a discourse on future perspectives, encompassing aspects of disease modeling, numerical challenges, and clinical applications, with a particular focus on aortic dissection. The aspiration is to inspire future studies, deepen our comprehension of the disease, and ultimately shape clinical care and treatment decisions.

The cornea, the transparent part of the anterior eye, is vital for light refraction and vision. This review examines the intricate chemical and biochemical interactions essential for maintaining corneal transparency and highlights significant advancements in corneal biology. The cornea comprises five layers: the epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium, each contributing uniquely to its structure and function. The epithelium, maintained by limbal stem cells, serves as a barrier and interacts with the tear film to maintain ocular surface health. The stroma, abundant in organized collagen fibrils and regulated by proteoglycans, is crucial for corneal clarity and biomechanical integrity, whereas the endothelium regulates corneal hydration and nutrition. Recent imaging advances have improved visualization of these molecular structures, enhancing our understanding of collagen organization and cross-linking. Proteoglycans such as decorin and lumican regulate collagen spacing and hydration, directly influencing corneal clarity. Biochemical processes within the cornea involve signaling molecules, growth factors, and cytokines, which are essential for wound healing, inflammation, and injury response. Despite progress, questions remain regarding corneal wound healing mechanisms, the impact of oxidative stress, and the roles of microRNAs. This review synthesizes recent discoveries to advance our understanding of corneal physiology and biochemical functions.

The skin, as a barrier organ meeting constant mechanical challenges, is equipped with multiple adhesive structures that collectively support resilient, yet flexible attachment of its epithelium -the epidermis to its mesenchyme - the dermis. One such structure is the collagen VII-composed anchoring fibril, which provides firm anchorage of the epidermal basement membrane to the underlying interstitial extracellular matrix. Blistering and wider tissue fragility in the genetic disease dystrophic epidermolysis bullosa (DEB) caused by collagen VII deficiency illustrate the essential function of collagen VII in supporting skin integrity. DEB is also a progressive inflammatory fibrotic disease with multi-organ involvement, indicating that collagen VII has broader functions than simply providing epithelial anchorage. This review explores the reciprocal relationship between collagen VII biology and DEB pathophysiology. A deeper understanding of collagen VII biology - spanning its synthesis, assembly into suprastructures, and regulatory roles - enhances our understanding of DEB. Conversely, detailed insights into DEB through analysis of disease progression or therapeutic interventions offer valuable information on the broader tissue and organismal roles of collagen VII in maintaining homeostasis. This review focuses on such knowledge exchange in advancing our understanding of collagen VII, the extracellular matrix in general, and inspiring potential strategies for treatment of DEB. Importantly, in a broader sense, the discussed themes are applicable to other conditions driven by compromised extracellular matrix instruction and integrity, leading to progressive damage and inflammation.

In patients on chronic peritoneal dialysis (PD), aortic stiffness (AS) is a common cardiovascular condition that can predict cardiovascular events and mortality. Decorin is a small leucine-rich proteoglycan that plays a vital role in extracellular matrix organization and vascular remodeling. The relationship between decorin and AS in patients with PD remains unclear. We enrolled 140 patients on PD and collected their demographic, anthropometric, and biochemical data. Serum decorin levels were measured using enzyme-linked immunosorbent assay. Based on carotid-femoral pulse wave velocity (cfPWV), a diagnosis of AS was established in 42 patients (30%), who were found to be of advanced age and showed higher prevalence rates of systolic blood pressure, diabetes, hypertension, triglyceride, fasting glucose, and lower decorin levels, compared with those who had no AS. After proper adjustment for confounding factors in the multivariable logistic regression model, AS development was associated with decorin, age, and triglyceride levels. Multivariable linear regression analysis showed that decorin, when subjected to logarithmic transformation, can be viewed as a significant independent predictor of cfPWV (β = -0.289; p < 0.001). Low decorin level was significantly and independently associated with AS in patients undergoing chronic PD.

The extracellular matrix (ECM) plays a crucial role in providing structural integrity and regulating cell communication essential for organ development, homeostasis, and regeneration, including hearts. Evidence indicates that disruptions in the spatiotemporal expression or alterations in ECM components lead to cardiac malformations, including a wide range of congenital heart diseases (CHDs). Furthermore, research on injured hearts across various vertebrate species, some of which show effective regeneration while others experience irreversible fibrosis, underscores the significance of ECM molecules in cardiac regeneration. This review presents an overview of heart development and the dynamics of ECM during cardiac morphogenesis, beginning with the formation of the contractile heart tube and advancing to the development of distinct chambers separated by valves to facilitate unidirectional blood flow. Furthermore, we discuss research emphasizing the multifaceted roles of secreted molecules in mediating fibrosis and regeneration following myocardial injury.

Small Leucine-Rich Proteoglycans (SLRPs) are a major family of vertebrate proteoglycans. In bony vertebrates, SLRPs have a variety of functions from structural to signaling and are found in extracellular matrices, notably in skeletal tissues. However, there is little or no data on the diversity, function and expression patterns of SLRPs in cartilaginous fishes, which hinders our understanding of how these genes evolved with the diversification of vertebrates, in particular regarding the early events of whole-genome duplications that shaped gnathostome and cyclostome genomes. We used a selection of chromosome-level assemblies of cartilaginous fish and other vertebrate genomes for phylogeny and synteny reconstructions, allowing better resolution and understanding of the evolution of this gene family in vertebrates. Novel SLRP members were uncovered together with specific loss events in different lineages. Our reconstructions support that the canonical SLRPs have originated from different series of tandem duplications that preceded the extant vertebrate last common ancestor, one of them even preceding the extant chordate last common ancestor. They then further expanded with additional tandem and whole-genome duplications during the diversification of extant vertebrates. Finally, we characterized the expression of several SLRP members in the small-spotted catshark Scyliorhinus canicula and from this, inferred conserved and derived SLRP expression in several skeletal and connective tissues in jawed vertebrates.

Chondrodysplasias with multiple dislocations are rare skeletal disorders characterized by hyperlaxity, joint dislocations, and growth retardation. Chondrodysplasias with multiple dislocations have been linked to pathogenic variants in genes encoding proteins involved in the proteoglycan (PG) biosynthesis. In this study, by exome sequencing analysis, we identified a homozygous nonsense variant (NM_001297654.2: c.1825C>T, p.Arg609*) in the discoidin domain receptor 1 (DDR1) gene in a patient presenting joint dislocations, hyperlaxity, and cerebellar hypoplasia. Functional studies revealed decreased PG production in patient fibroblasts. We further demonstrated that DDR1 inhibition impaired the Indian Hedgehog signaling pathway in chondrocytes, decreased differentiation and mineralization in osteoblasts, and disrupted p38 MAPK signaling in both cell types. Additionally, we showed that DDR1 inhibition affected the noncanonical WNT signaling pathway in human skeletal cells and decreased PG production in chondrocytes. These findings suggest that DDR1 is a new gene involved in the group of chondrodysplasias with multiple dislocations and highlights its essential role in human skeletal and brain development.

Hepatocellular carcinoma (HCC) corresponds to the vast majority of liver cancer cases, with one of the highest mortality rates. Major advances have been made in this field both in the characterization of the molecular pathogenesis and in the development of systemic therapies. Despite these achievements, biomarkers and more efficient treatments are still needed to improve its management. Heparan sulfate (HS) chains are polysaccharides that are present at the cell surface or in the extracellular matrix that are able to bind various types of molecules, such as soluble factors, affecting their availability and thus their effects, or to contribute to interactions that position cells in their environments. Enzymes can modify HS chains after their synthesis, thus changing their properties. Numerous studies have shown HS-related proteins to be key actors that are associated with cellular effects, such as tumor growth, invasion, and metastasis, including in the context of liver carcinogenesis. The aim of this review is to provide a comprehensive overview of the biology of HS chains and their potential importance in HCC, from biological considerations to clinical development, and the identification of biomarkers, as well as therapeutic perspectives.

Tumors often exhibit greater stiffness compared to normal tissues, primarily due to increased deposition within the tumor stroma. Collagen, proteoglycans, laminin, and fibronectin are key components of the extracellular matrix (ECM), interacting to facilitate ECM assembly. Enhanced fiber density and cross-linking within the ECM result in elevated matrix stiffness and interstitial fluid pressure, subjecting tumors to significant physical stress during growth. This mechanical stress is transduced intracellularly via integrins, the Rho signaling pathway, and the Hippo signaling pathway, thereby promoting tumor invasion. Additionally, mechanical pressure fosters glycolysis in tumor cells, boosting energy production to support metastasis. Mechanical cues also regulate macrophage polarization, maintaining an inflammatory microenvironment conducive to tumor survival. In summary, mechanical signals within tumors play a crucial role in tumor growth and invasion. Understanding these signals and their involvement in tumor progression is essential for advancing our knowledge of tumor biology and enhancing therapeutic approaches.

Fibroblasts, crucial for maintaining tissue homeostasis, significantly shape the tumor microenvironment (TME). In pancreatic cancer, a highly aggressive malignancy, cancer-associated fibroblast (CAF)/extracellular matrix (ECM) units dominate the TME, influencing tumor initiation, progression, and treatment responses. Palladin, an actin-associated protein, is vital for fibroblast structural integrity and activation, playing a key role in CAF/ECM functionality. Palladin interacts with cytoskeletal proteins such as alpha-actinin (α-Act) and can therefore regulate other proteins like syndecans, modulating cytoskeletal features, cell adhesion, integrin recycling, and signaling. In this review, we propose that targeting the palladin/α-Act/syndecan interaction network could modulate CAF/ECM units, potentially shifting the TME from a tumor-promoting to a tumor-suppressive state. In silico data and reported studies to suggest that stabilizing palladin-α-Act interactions, via excess palladin, influences syndecan functions; potentially modulating integrin endocytosis via syndecan engagement with protein kinase C alpha as opposed to syndecan binding to α-Act. This mechanism can then affect the distribution of active α5β1-integrin between the plasma membrane and known intracellular vesicular compartments, thereby influencing the tumor-suppressive versus tumor-promoting functions of CAF/ECM units. Understanding these interactions offers likely future therapeutic avenues for stroma normalization in pancreatic and other cancers, aiming to inhibit tumor progression and improve future treatment outcomes.

Proteoglycans are an ample family of complex extracellular matrix/cell surface components known to impact on virtually all biological processes that take place during life of a human being, in its healthy and diseased conditions. They are consolidated multivalent regulators of the behaviour of normal and malignant hematopoietic cells because of being critical components of their membranes, because of their pivotal role as multifaceted factors of the hematopoietic niches and because of acting as pillars of the tumour microenvironment. Likewise, they act as promoters of the growth, spreading and therapeutic resistance of diseased hematopoietic cells, also by modulating intracellular processes through a dual utilization of core protein domains and their glycosaminoglycan side chains. The intricate pattern of expression of the myriads of proteoglycan isoforms generated by differential glycanations of the core proteins is differentiation- and cell activation-dependent and often associates with genomic aberrations and gene amplifications. Selected proteoglycans stand out as widely recognized, disease type-specific markers and as alluring but still unappreciated therapeutic targets. We therefore pose here a clinical-translational view on the hematopoietic proteoglycome to highlight its underestimated biological and pathological significance during normal and neoplastic hematopoiesis. We underscore the potential of several proteoglycans to be exploited as key markers for prognostication and therapeutic targeting of hematopoietic cancers.

In recent years, several studies have shown that HSPG2 is associated with the prognosis of specific cancers. The aim of this study was to investigate the prognostic value of HSPG2 in pan-cancer and to analyze its possible mechanisms.

We used The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) to explore the expression of HSPG2 in 33 tumors and corresponding controls. Univariate Cox regression and Kaplan-Meier survival analysis were applied to detect the effects of HSPG2 on overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI) in patients with these tumors, and to analyze the relationship between HSPG2 and clinical characteristics. And we further analyzed the relationship between HSPG2 and immune infiltration, DNA methylation and single cell function. And GO and KEGG enrichment analyses were performed using HSPG2 co-expressed genes. Finally, we explored the diagnostic efficacy of HSPG2 for diseases of interest and validated it using qPCR experiment.

HSPG2 was lowly expressed in 17 cancers and highly expressed in 11 cancers, and was correlated with patient's clinical characteristics in many cancers. Multivariate regression analysis showed that HSPG2 was an independent prognostic factor for DSS, OS, and PFI in bladder urothelial carcinoma (BLCA) and Mesothelioma (MESO). HSPG2 was correlated with DNA methylation, single-cell function, and immune infiltration in a variety of cancers. HSPG2 exhibited a good diagnostic efficacy for BLCA and MESO. qPCR and western blot results showed that HSPG2 expression was increased in mesothelioma compared to normal controls.

These findings suggest that HSPG2 could be considered as a potential diagnostic and prognostic marker for BLCA and MESO.

Preeclampsia (PE) is a gestational complication affecting 5% to 10% of all pregnancies. PE is characterized by hypertension and endothelial dysfunction, whose etiology involves, among other factors, alterations in the extracellular matrix (ECM) that can compromise vascular remodeling and trophoblast invasion, ie, processes essential for placental development. Endothelial dysfunction is caused by release of antiangiogenic factors, mainly a soluble fms-like tyrosine kinase-1 (sFlt-1), which antagonizes two endothelial angiogenic factors, the vascular endothelial growth factor (VEGF) and placental growth factor (PLGF). This angiogenic imbalance contributes to clinical symptoms including hypertension and multisystem dysfunction. This review aims to summarize recent advances in understanding PE, particularly with altered ECM components such as heparan sulfate proteoglycans, the glycosidase heparanase, fibronectin, collagen XVIII (endostatin), and metalloproteases. This comprehensive narrative review was conducted on PubMed from 1994 to 2024, focusing on articles on the pathophysiology of PE, particularly endothelial dysfunction caused by ECM modifications. The data shows a reduced expression of matrix metalloproteinases, increased collagen fragment XVIII, and significant changes in fibronectin associated with PE. Furthermore, endothelial dysfunction was associated with increased degradation of heparan sulfate chains from proteoglycans and increased sFlt-1. Understanding these ECM modifications is crucial for developing potential new therapeutic interventions that improve maternal and fetal outcome in PE.

The extracellular matrix is a complex network of macromolecules that support the growth and homeostatic development of organisms. By conveying multiple signaling cascades, it impacts on several biological processes and influences the behaviour of numerous cell types. During the endometrial cycle and the key events necessary for a correct embryo implantation and placentation, this bioactive meshwork is substantially modified to favour endometrial receptivity and vascular adaptation, trophoblast cell migration, and immune activation as well. A correct extracellular remodeling is fundamental for the establishment of a physiological pregnancy; indeed, the occurrence of altered matrix modifications associates with gestational disorders such as preeclampsia. In the present review, we will critically evaluate the role of pivotal matrix constituents in regulating the key steps of embryo implantation and placentation, provide up-to-date information concerning their primary mechanisms of action and discuss on their potential as a novel source of biomarkers and therapeutic targets.

The aim of this study was to evaluate the influence of diluent, stored volume and the cryodiluent medium supplementation with sulfated polysaccharides (SP) extracted from Nile tilapia skin on P. brevis vitrified sperm. Six pools were diluted in 5% Glucose or Powder Coconut Water (ACP-104), supplemented or not with 0.5 mg/mL of SP, and submitted to vitrification. Subsequently, they were stored in cryotubes in two volumes (60 μL and 420 μL). After 15 days, the samples were devitrified and evaluated for kinetics, membrane integrity and sperm DNA integrity. ACP-104 proved to be the best diluent for P. brevis sperm vitrification. Membrane and DNA integrity rates were higher (P < 0.05) when stored in smaller and larger volume, respectively. Additionally, the best rates (P < 0.05) of these same parameters were obtained with supplemented medium. There was interaction (P < 0.05) between diluent and stored volume, with ACP-104 exceeding 5% Glucose for motility in both volumes, while for average path speed (VAP) and membrane integrity the same happened in the larger volume. 5% Glucose had higher VAP and membrane integrity when stored in smaller volume. There was a triple interaction (P < 0.05) for DNA integrity, and better results were obtained when semen was vitrified in ACP-104 and stored in the larger volume, regardless of supplementation, which influenced only the 5% Glucose medium in the smaller volume. It was concluded that ACP-104, supplemented with SP and stored in larger volume make up the best treatment for P. brevis sperm vitrification.

Mast cells exert multiple roles beyond their classical role in IgE-mediated allergic reactions. These cells secrete pro-inflammatory and anti-inflammatory agents and change from protective immune cells to pro-inflammatory cells, capable of influencing the progression of different pathological conditions, including tumors, in which they exert anti-tumorigenic and pro-tumorigenic roles. In this context, this article analyzes the potential role played by mast cell-derived proteases in tumor progression and more specifically in driving metastatic process and the potential therapeutic approaches that inhibiting the activation of these cells could help faith cancer spreading.

There is a current lack of consensus on whether the ancestral parity mode was oviparity (egg-laying) or viviparity (live-birth) in amniotes and particularly in squamates (snakes, lizards, and amphisbaenids). How transitions between parity modes occur at the genomic level has primary importance for how science conceptualises the origin of amniotes, and highly variable parity modes in Squamata. Synthesising literature from medicine, poultry science, reproductive biology, and evolutionary biology, I review the genomics and physiology of five broad processes (here termed the 'Main Five') expected to change during transitions between parity modes: eggshell formation, embryonic retention, placentation, calcium transport, and maternal-fetal immune dynamics. Throughout, I offer alternative perspectives and testable hypotheses regarding proximate causes of parity mode evolution in amniotes and squamates. If viviparity did evolve early in the history of lepidosaurs, I offer the nucleation site hypothesis as a proximate explanation. The framework of this hypothesis can be extended to amniotes to infer their ancestral state. I also provide a mechanism and hypothesis on how squamates may transition from viviparity to oviparity and make predictions about the directionality of transitions in three species. After considering evidence for differing perspectives on amniote origins, I offer a framework that unifies (i) the extended embryonic retention model and (ii) the traditional model which describes the amniote egg as an adaptation to the terrestrial environment. Additionally, this review contextualises the origin of amniotes and parity mode evolution within Medawar's paradigm. Medawar posited that pregnancy could be supported by immunosuppression, inertness, evasion, or immunological barriers. I demonstrate that this does not support gestation or gravidity across most amniotes but may be an adequate paradigm to explain how the first amniote tolerated internal fertilization and delayed egg deposition. In this context, the eggshell can be thought of as an immunological barrier. If serving as a barrier underpins the origin of the amniote eggshell, there should be evidence that oviparous gravidity can be met with a lack of immunological responses in utero. Rare examples of two species that differentially express very few genes during gravidity, suggestive of an absent immunological reaction to oviparous gravidity, are two skinks Lampropholis guichenoti and Lerista bougainvillii. These species may serve as good models for the original amniote egg. Overall, this review grounds itself in the historical literature while offering a modern perspective on the origin of amniotes. I encourage the scientific community to utilise this review as a resource in evolutionary and comparative genomics studies, embrace the complexity of the system, and thoughtfully consider the frameworks proposed.

Proline/arginine-rich end and leucine-rich protein (PRELP) is identified as a small proteoglycan in the extracellular matrix that has been tightly associated with cell adhesion. At present, the role of PRELP in colorectal cancer (CRC) remains largely unknown. PRELP expression in human CRC tissue samples was analyzed by qRT-PCR and immunochemistry. CCK-8, colony formation, transwell, and tube formation assays were utilized to determine the influences of PRELP on the malignant phenotypes of CRC cells. Mouse xenograft and tumor metastasis models were constructed to further validate the function of PRELP. Furthermore, we investigated the efficacy of PRELP combined with bevacizumab treatment in a mouse xenograft model of CRC. Additionally, RNA-seq was performed to analyze the potential signaling pathways regulated by PRELP. Immunofluorescence staining and coimmunoprecipitation were conducted to confirm the interaction between PRELP and fibroblast growth factor 1 (FGF1). In this study, we found that PRELP exerted a tumor-suppressive effect on CRC. The expression level of PRELP was significantly reduced in CRC tissues and cell lines. Both in vivo and in vitro experiments confirmed that PRELP inhibited CRC cell proliferation, promoted apoptosis, and suppressed migration and invasion via a reduction in the epithelial-mesenchymal transition and attenuated angiogenesis, thereby dampening tumor progression. In addition, PRELP markedly potentiated the efficacy of bevacizumab in a mouse xenograft model. Mechanistically, PRELP bound to FGF1 and reduced the stability of the FGF1 protein, accompanied by an increase in its degradation, which subsequently inactivated the PI3K/AKT/mTOR pathway, thereby leading to reduction in tumor angiogenesis and metastasis. Our study for the first time unveiled the tumor-suppressive role of PRELP in CRC and provided a potential effective strategy for the treatment of CRC.

Glycosaminoglycans (GAGs), as animal polysaccharides, are linked to proteins to form various types of proteoglycans. Bacterial GAG lyases are not only essential enzymes that spoilage bacteria use for the degradation of GAGs, but also valuable tools for investigating the biological function and potential therapeutic applications of GAGs. The ongoing discovery and characterization of novel GAG lyases has identified an increasing number of lyases suitable for functional studies and other applications involving GAGs, which include oligosaccharide sequencing, detection and removal of specific glycan chains, clinical drug development and the design of novel biomaterials and sensors, some of which have not yet been comprehensively summarized. GAG lyases can be classified into hyaluronate lyases, chondroitinases and heparinases based on their substrate spectra, and their functional applications are mainly determined by their substrates, with different lyases exhibiting differing substrate selectivity and preferences. It is thus necessary to understand the properties of the available enzymes to determine strategies for their functional application. Building on previous studies and reviews, this Review highlights small yet crucial differences among or within the various GAG lyases to aid in optimizing their use in future studies. To clarify ideas and strategies for further research, we also discuss several traditional and novel applications of GAG lyases.

Proteoglycans, key components of non-collagenous proteins in the bone matrix, attract water through their negatively charged glycosaminoglycan chains. Among these proteoglycans, biglycan (Bgn) and decorin (Dcn) are major subtypes, yet their distinct roles in bone remain largely elusive. In this study, we utilized single knockout (KO) mouse models and successfully generated double KO (dKO) models despite challenges with low yield. Bgn deficiency, but not Dcn deficiency, decreased trabecular bone mass, with more pronounced bone loss in dKO mice. Low-field nuclear magnetic resonance measurements showed a marked decrease in bound water among all KO groups, especially in Bgn KO and dKO mice. Moreover, both Bgn KO and dKO mice exhibited reduced fracture toughness compared to Dcn KO mice. Dcn was significantly upregulated in Bgn KO mice, while a modest upregulation of Bgn was observed in Dcn KO mice, indicating Bgn's predominant role in bone. High resolution atomic force microscopy showed decreased in situ permanent energy dissipation and increased elastic modulus in the extrafibrillar matrix of Bgn/Dcn deficient mice, which were diminished upon dehydration. Furthermore, we found that both Bgn and Dcn are indispensable for the activation of ERK and p38 MAPK signaling pathways. Collectively, our results highlight the distinct and indispensable roles of Bgn and Dcn in maintaining bone structure, water retention, and bulk/in situ tissue properties in the bone matrix, with Bgn exerting a predominant influence.

Mass spectrometry-based investigation of the heterogeneous glycoproteome from complex biological specimens is a robust approach to mapping the structure, function, and dynamics of the glycome and proteome. Sampling whole wet tissues often provides a large amount of starting material; however, there is a reasonable variability in tissue handling prior to downstream processing steps, and it is difficult to capture all the different biomolecules from a specific region. The on-slide tissue digestion approach, outlined in this protocol chapter, is a simple and cost-effective method that allows comprehensive mapping of the glycoproteome from a single spot of tissue of 1 mm or greater diameter. It provides a selection of target areas on tissue slides appropriate for tissue volumes of 10 nL or greater, corresponding to a 1 μL droplet of enzyme solution applied to a 1-mm diameter target on a 10-μm-thick tissue slice. Sequential enzymatic digestions and desalting of the biomolecules without any prior derivatization from the surface of fresh frozen or formalin-fixed paraffin-embedded tissue slides enable the simultaneous identification of glycosaminoglycan disaccharides such as hyaluronan, chondroitin sulfate and heparan sulfate, asparagine or N-linked glycans, and intact (glyco)peptides using liquid chromatography-tandem mass spectrometry. The in-depth information obtained from this method including the disaccharide compositions, glycan structures, peptide abundances, and site-specific glycan occupancies provides a detailed profiling of a single spot of tissue which has the potential to be disseminated to biomedical laboratories.

This chapter provides a comprehensive overview of the roles of astrocytes, microglia, and the extracellular matrix (ECM) in regulating neuroplasticity and maintaining brain homeostasis. Astrocytes provide essential metabolic support to neurons, regulate synapse development, support neuroplasticity mechanisms, and modulate neurotransmission. Microglia, the resident immune cells of the brain, play a critical role in neuroinflammatory responses and homeostatic brain regulation by modulating synapse formation and pruning. The extracellular space (ECS) mediates intercellular interactions, provides a highly regulated environment for intercellular communication, and is filled with ECM molecules. Proteoglycans and polysaccharides of the ECM play a vital role not only in brain development but also in brain function throughout life. In the injured brain, neuroplasticity and regeneration can be bidirectionally regulated as a result of the interplay between ECM, astrocytes, and microglia. The modulation of synaptic strength, structural remodeling, and modification of intrinsic neuronal properties are among the central mechanisms that contribute to neuronal plasticity in health and disease. We believe that the understanding of ECM-glia interactions and their role in neuroplasticity regulation is key to the development of novel therapeutic strategies in neurologic disorders.

Solid tumors present a formidable challenge in oncology, necessitating innovative approaches to improve therapeutic outcomes. Proteoglycans, multifaceted molecules within the tumor microenvironment, have garnered attention due to their diverse roles in cancer progression. Their unique ability to interact with specific membrane receptors, growth factors, and cytokines provides a promising avenue for the development of recombinant proteoglycan-based therapies that could enhance the precision and efficacy of cancer treatment. In this study, we performed a comprehensive analysis of the proteoglycan gene landscape in human breast carcinomas. Leveraging the available wealth of genomic and clinical data regarding gene expression in breast carcinoma and using a machine learning model, we identified a unique gene expression signature composed of five proteoglycans differentially modulated in the tumor tissue: Syndecan-1 and asporin (upregulated) and decorin, PRELP and podocan (downregulated). Additional query of the breast carcinoma data revealed that serglycin, previously shown to be increased in breast carcinoma patients and mouse models and to correlate with a poor prognosis, was indeed decreased in the vast majority of breast cancer patients and its levels inversely correlated with tumor progression and invasion. This proteoglycan gene signature could provide novel diagnostic capabilities in breast cancer biology and highlights the need for further utilization of publicly available datasets for the clinical validation of preclinical experimental results.

Time-resolved fluorescence immunochromatographic test strips (TRFIS) was developed for the rapid detection of hepatocellular carcinoma (HCC)-specific plasma exosomes (hExos) by targeting the hExo-surface membrane protein glypican-3 (GPC3). The GPC3-TRFIS could directly detect plasma exosomes without the isolation and purification process, and the whole immunoassay could be completed within 15 min. The visual detection limit of GPC3-TRFIS was 3.44 × 10^9 particles/mL, with a minimum detection limit of 1.8 × 10^9 particles/mL. For analysis of the clinical HCC samples, GPC3-TRFIS shows high specificity for detection of hExo, and was nearly unreactive for healthy donors' samples. GPC3-TRFIS was able to efficiently distinguish HCC patients (19 cases) from healthy donors (19 cases). Overall, the developed TRFIS offers the benefits of high sensitivity, simple operation, and no need of large precision instruments and professional technical personnel for rapid detection of plasma hExos, and supplies a novel approach for early screening of HCC.

The complex collagen network of the native meniscus and the gradient of the density and alignment of this network through the meniscal enthesis is essential for the proper mechanical function of these tissues. This architecture is difficult to recapitulate in tissue-engineered replacement strategies. Prenatally, the organization of the collagen fiber network is established and aggrecan content is minimal. In vitro, fibrochondrocytes (FCCs) produce proteoglycans and associated glycosaminoglycan (GAG) chains early in culture, which can inhibit collagen fiber formation during the maturation of tissue-engineered menisci. Thus, it would be beneficial to both specifically and temporarily block deposition of proteoglycans early in culture. In this study, we transiently inhibited aggrecan production by meniscal fibrochondrocytes using siRNA in collagen gel-based tissue-engineered constructs. We evaluated the effect of siRNA treatment on the formation of collagen fibrils and bulk and microscale tensile properties. Specific inhibition of aggrecan production by fibrochondrocytes via siRNA was successful both in 2D monolayer cell culture and 3D tissue culture. This inhibition during early maturation of these in vitro constructs increased collagen fibril diameter by more than 2-fold. This increase in fibril diameter allowed these tissues to distribute strains more effectively at the local level, particularly at the interface of the bone and soft tissue. These data show that siRNA can be used to modulate the ECM to improve collagen fiber formation and mechanical properties in tissue-engineered constructs, and that a transient decrease in aggrecan promotes the formation of a more robust fiber network.

Corneal injury-induced fibrosis occurs because of corneal epithelial basement membrane (EBM) injury and defective regeneration. Corneal fibrosis inhibition and transparency restoration depend on reestablished EBM, where the collagen network provides structural stability and heparan sulfate binds corneal epithelium-derived cytokines to regulate homeostasis. Inspired by this, bioactive hydrogels (Hep@Gel) composed of collagen-derived gelatins and highly anionic heparin were constructed for scarless corneal repair. Hep@Gel resembled the barrier function of the EBM regarding surface-confined binding, long-time sequestration, and progressive degradation of IL-1, TGF-β, and PDGF-BB, which robustly inhibited the apoptosis and myofibroblast transition of keratocytes. Animal models of rabbits and nonhuman primates confirmed that Hep@Gel effectively limited the influx of inflammatory and fibrotic cytokines from the epithelium into the stroma to down-regulate the wound healing cascade, contributing to better vision quality with 73% reduced fibrosis. Hep@Gel offers a solution for preventing corneal injury-induced scarring and substituting for lamellar keratoplasty to remove scarring.

Heparan sulfate (HS) and chondroitin sulfate (CS) proteoglycans (PG) consist of a core protein to which the glycosaminoglycan (GAG) chains, HS or CS, are attached through a common linker tetrasaccharide. In the extracellular space, they are involved in the regulation of cell communication, assuring development and homeostasis. The HSPG biosynthetic pathway has documented 51 genes, with many diseases associated to defects in some of them. The phenotypic consequences of this genetic variation in humans, and of genetic ablation in mice, and their expression patterns, led to a phenotypically centered HSPG biosynthetic pathway model. In this model, HS sequences produced by ubiquitous NDST1, HS2ST and HS6ST enzymes are essential for normal development and homeostasis, whereas tissue restricted HS sequences produced by the non-ubiquitous NDST2-4, HS6ST2-3, and HS3ST1-6 enzymes are involved in adaptative behaviors, cognition, tissue responsiveness to stimuli, and vulnerability to disease. The model indicates that the flux through the HSPG/CSPG pathways and its diverse branches is regulated by substrate preferences and protein-protein-interactions. This results in a privileged biosynthesis of HSPG over that of CSPGs, explaining the phenotypes of linkeropathies, disease caused by defects in genes involved in the biosynthesis of the common tetrasaccharide linker. Documented feedback loops whereby cells regulate HS sulfation, and hence the interactions of HS with protein partners, may be similarly implemented, e.g., protein tyrosine sulfation and other posttranslational modifications in enzymes of the HSPG pathway. Together, ubiquitous HS, specialized HS, and their biosynthesis model can facilitate research for a better understanding of HSPG roles in physiology and pathology.

Fibrosis is defined by the excessive accumulation of extracellular matrix (ECM) and constitutes a central pathophysiological process that underlies tissue dysfunction, across organs, in multiple chronic diseases and during aging. Myocardial fibrosis is a key contributor to dysfunction and failure in numerous diseases of the heart and is a strong predictor of poor clinical outcome and mortality. The excess structural and matricellular ECM proteins deposited by cardiac fibroblasts, is found between cardiomyocytes (interstitial fibrosis), in focal areas where cardiomyocytes have died (replacement fibrosis), and around vessels (perivascular fibrosis). Although myocardial fibrosis has important clinical prognostic value, access to cardiac tissue biopsies for histological evaluation is limited. Despite challenges with sensitivity and specificity, cardiac magnetic resonance imaging (CMR) is the most applicable diagnostic tool in the clinic, and the scientific community is currently actively searching for blood biomarkers reflecting myocardial fibrosis, to complement the imaging techniques. The lack of mechanistic insights into specific pro- and anti-fibrotic molecular pathways has hampered the development of effective treatments to prevent or reverse myocardial fibrosis. Development and implementation of anti-fibrotic therapies is expected to improve patient outcomes and is an urgent medical need. Here, we discuss the importance of the ECM in the heart, the central role of fibrosis in heart disease, and mechanistic pathways likely to impact clinical practice with regards to diagnostics of myocardial fibrosis, risk stratification of patients, and anti-fibrotic therapy.

Ectodermal organs, such as hair follicles, originate from simple epithelial and mesenchymal sheets through a complex developmental process driven by interactions between these cell types. This process involves dermal condensation, placode formation, bud morphogenesis, and organogenesis, and all of these processes require intricate interactions among various tissues. Recent research has emphasized the crucial role of reciprocal and dynamic interactions between cells and the extracellular matrix (ECM), referred to as the "dynamic duo", in the development of ectodermal organs. These interactions provide spatially and temporally changing biophysical and biochemical cues within tissues. Using the hair follicle as an example, this review highlights two types of cell-ECM adhesion units-focal adhesion-type and hemidesmosome-type adhesion units-that facilitate communication between epithelial and mesenchymal cells. This review further explores how these adhesion units, along with other cell-ECM interactions, evolve during hair follicle development and regeneration, underscoring their importance in guiding both developmental and regenerative processes.

Larvacean tunicates feature a spectacular innovation not seen in other animals - the trunk oikoplastic epithelium (OE). This epithelium produces a house, a large and complex extracellular structure used for filtering and concentrating food particles. Previously we identified several homeobox transcription factor genes expressed during early OE patterning. Among these are two Pax3/7 copies that we named pax37A and pax37B. The vertebrate homologs, PAX3 and PAX7 are involved in developmental processes related to neural crest and muscles. In the ascidian tunicate Ciona intestinalis, Pax3/7 plays a role in the development of cells deriving from the neural plate border, including trunk epidermal sensory neurons and tail nerve cord neurons, as well as in the neural tube closure. Here we have investigated the roles of Oikopleura dioica pax37A and pax37B in the development of the OE, by using CRISPR-Cas9 mutant lines and analyzing scRNA-seq data from wild-type animals. We found that pax37B but not pax37A is essential for the differentiation of cell fields that produce the food concentrating filter of the house: the anterior Fol, giant Fol and Nasse cells. Trajectory analysis supported a neuroepithelial-like or a preplacodal ectoderm transcriptional signature in these cells. We propose that the highly specialized secretory epithelial cells of the Fol region either maintained or evolved neuroepithelial features. This is supported by a fragmented gene regulatory network involved in their development that also operates in ascidian epidermal neurons.

Cartilage destruction in juvenile idiopathic arthritis (JIA) is diagnosed, often too late, on basis of clinical evaluation and radiographic imaging. This case-control study investigated serum chondroitin/dermatan sulfate (CS/DS) as a potential biochemical marker of cartilage metabolism, aiming to improve early diagnosis and precision treatment for JIA. We also measured the levels of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-binding protein-3 (IGFBP-3) (using ELISA methods) in JIA patients (n = 55) both before and after treatment (prednisone, sulfasalazine, methotrexate, administered together), and analyzed their relationships with CS/DS levels. Untreated JIA patients [8.26 µg/mL (6.25-9.66)], especially untreated girls [8.57 µg/mL (8.13-9.78)] and patients with a polyarticular form of the disease [7.09 µg/mL (5.63-8.41)], had significantly reduced levels of serum CS/DS compared with the control [14.48 µg/mL (10.23-15.77)]. Therapy resulted in a significant increase in this parameter, but without normalization. We also found significantly lower levels of IGF-1 [66.04 ng/mL (49.45-96.80)] and IGFBP-3 [3.37 ng/mL (2.65-4.88)] in untreated patients compared with the control [96.92 ng/mL (76.04-128.59), 4.84 ng/mL (4.21-7.750), respectively]. Based on receiver operating characteristic (ROC) curve analysis, the blood concentration of CS/DS demonstrated the highest diagnostic power (AUC = 0.947) for JIA among all the tested markers. Untreated patients showed significant correlations between CS/DS and IGF-1 (r = -0.579, p = 0.0000), IGFBP-3 (r = -0.506, p = 0.0001), and C-reactive protein (r = 0.601, p = 0.0005). The observed changes in CS/DS during the course of JIA, influenced by both impairment of the IGF/IGFBP axis and inflammation, indicate the need for continued therapy to protect patients from potential disability. We suggest that CS/DS may be a useful biomarker of disease activity and could be employed to assess treatment efficacy and progress toward remission.

Hypothyroidism, a condition characterized by decreased synthesis and secretion of thyroid hormones, significantly impacts intellectual development and physical growth. Current treatments, including hormone replacement therapy and thyroid transplantation, have limitations due to issues like hormone dosage control and immune rejection. Tissue engineering presents a potential solution by combining cells and biomaterials to construct engineered thyroid tissue. This study focuses on the development and characterization of a novel 3D injectable hydrogel derived from thyroid extracellular matrix (TEM) for thyroid tissue engineering. TEM hydrogels were prepared through decellularization of rat thyroid tissue, followed by extensive physicochemical and mechanical property evaluations. The TEM hydrogels exhibited properties similar to natural thyroid tissue, including high biocompatibility and a complex 3D ultrastructure. Thyroid hormone-secreting cells cultured in TEM hydrogels demonstrated superior viability, hormone secretion, and thyroid-related gene expression compared to those in traditional type I collagen hydrogels. The study also confirmed the significant retention of key growth factors and ECM proteins within the TEM hydrogels. The results indicate that TEM hydrogels can provide a biomimetic microenvironment, promoting the long-term survival and function of thyroid cells, thus holding great promise for the treatment of hypothyroidism. This research contributes a potential new avenue for thyroid tissue engineering, offering a promising alternative for hypothyroidism treatment.

The injection of bone mesenchymal stem cells (BMSCs) for osteoarthritis (OA) treatment fails to address the disrupted extracellular microenvironment, limiting the differentiation and paracrine functions of BMSCs and resulting in suboptimal therapeutic outcomes. Proteoglycans (PGs) promote cell differentiation, tissue repair, and microenvironment remodeling. This study investigated the potential of combining PGs with BMSCs to increase the efficacy of OA treatment.

We evaluated the effects of PG on BMSC and chondrocyte functions by adding various PG concentrations to the culture media. Additionally, a Transwell system was used to assess the impact of PG on the communication between BMSCs and chondrocytes. The results of the in vitro experiment were verified by tissue staining and immunohistochemistry following the treatment of OA model rats.

Our findings indicate that PG effectively induces Col II expression in BMSCs and enhances the paracrine secretion of TGF-β1, thereby activating the TGF-β signaling pathway in chondrocytes and increasing PRG4 gene expression. Compared with the other groups, the BMSC/PG treatment group presented a smoother articular surface and more robust extracellular matrix than the other groups in vivo, with significantly increased expression and distribution of Smad2/3 and PRG4.

PG enhances BMSC differentiation into chondrocytes and stimulates paracrine TGF-β1 secretion. Proteoglycans not only promote chondrocyte differentiation and paracrine TGF-β1 signaling in BMSCs but also increase the sensitivity of chondrocytes to TGF-β1 secreted from BMSCs, leading to PRG4 expression through the TGFR/Smad2/3 pathway. Proteoglycans can enhance the therapeutic effect of BMSC treatment on OA and have the potential to delay the degeneration of OA cartilage.

The extracellular matrix (ECM) plays a central role in the structural integrity and functionality of the cardiovascular system. Moreover, the ECM is involved in atherosclerotic plaque formation and stability. In fact, ECM remodeling affects plaque stability, cellular migration, and inflammatory responses. Collagens, fibronectin, laminin, elastin, and proteoglycans are crucial proteins during atherosclerosis development. This dynamic remodeling is driven by proteolytic enzymes such as matrix metalloproteinases (MMPs), cathepsins, and serine proteases. Exploring and investigating ECM dynamics is an important step to designing innovative therapeutic strategies targeting ECM remodeling mechanisms, thus offering significant advantages in the management of cardiovascular diseases. This review illustrates the structure and role of vascular ECM, presenting a new perspective on ECM remodeling and its potential as a therapeutic target in atherosclerosis treatments.

Type I collagen is the most abundant structural protein in the body and, with other fibrillar collagens, forms the fibrous network of the extracellular matrix. Another group of extracellular matrix polymers, the glycosaminoglycans, and glycosaminoglycan-modified proteoglycans, play important roles in regulating collagen behaviors and contribute to the compositional, structural, and mechanical complexity of the extracellular matrix. While the binding between collagen and small leucine-rich proteoglycans has been studied in detail, the interactions between collagen and the large bottlebrush proteoglycan versican are not well understood. Here, we report that versican binds collagen directly and regulates collagen structure and mechanics. Versican colocalizes with collagen fibers in vivo and binds to collagen via its C-terminal G3 domain (a non-GAG-modified domain present in all known versican isoforms) in vitro; it promotes the deposition of a highly aligned collagen-rich matrix by fibroblasts. Versican also shows an unexpected effect on the rheology of collagen gels in vitro, causing decreased stiffness and attenuated shear strain stiffening, and the cleavage of versican in the liver results in reduced tissue compression stiffening. Thus, versican is an important collagen-binding partner and plays a role in modulating collagen organization and mechanics.