Component Of Extracellular Matrices Research Articles

Identification of CD44 as a key mediator of cell traction force generation in hyaluronic acid-rich extracellular matrices.

Mechanical properties of the extracellular matrix (ECM) critically regulate a number of important cell functions including growth, differentiation and migration. Type I collagen and glycosaminoglycans (GAGs) are two primary components of ECMs that contribute to mammalian tissue mechanics, with the collagen fiber network sustaining tension, and GAGs withstanding compression. The architecture and stiffness of the collagen network are known to be important for cell-ECM mechanical interactions via integrin cell surface adhesion receptors. In contrast, studies of GAGs in modulating cell-ECM interactions are limited. Here, we present experimental studies on the roles of hyaluronic acid (HA, an unsulfated GAG) in single tumor cell traction force generation using a recently developed 3D cell traction force microscopy method. Our work reveals that CD44, a cell surface adhesion receptor to HA, is engaged in cell traction force generation in conjunction with β1-integrin. We find that HA significantly modifies the architecture and mechanics of the collagen fiber network, decreasing tumor cells' propensity to remodel the collagen network, attenuating traction force generation, transmission distance, and tumor invasion. Our findings point to a novel role for CD44 in traction force generation, which can be a potential therapeutic target for diseases involving HA rich ECMs such as breast cancer and glioblastoma.

Structural insights into the biological functions of the long pentraxin PTX3.

Soluble pattern recognition molecules (PRMs) are a heterogenous group of proteins that recognize pathogen- and danger-associated molecular patterns (PAMPs and DAMPs, respectively), and cooperate with cell-borne receptors in the orchestration of innate and adaptive immune responses to pathogenic insults and tissue damage. Amongst soluble PRMs, pentraxins are a family of highly conserved proteins with distinctive structural features. Originally identified in the early 1990s as an early inflammatory gene, PTX3 is the prototype of long pentraxins. Unlike the short pentraxin C reactive protein (CRP), whose expression is mostly confined to the liver, PTX3 is made by several immune and non-immune cells at sites of infection and inflammation, where it intercepts fundamental aspects of infection immunity, inflammation, and tissue remodeling. Of note, PTX3 cross talks to components of the complement system to control cancer-related inflammation and disposal of pathogens. Also, it is an essential component of inflammatory extracellular matrices (ECMs) through crosslinking of hyaluronic acid and turn-over of provisional fibrin networks that assemble at sites of tissue injury. This functional diversity is mediated by unique structural characteristics whose fine details have been unveiled only recently. Here, we revisit the structure/function relationships of this long pentraxin in light of the most recent advances in its structural biology, with a focus on the interplay with complement and the emerging roles as a component of the ECM. Differences to and similarities with the short pentraxins are highlighted and discussed.

Extracellular matrix biomechanical roles and adaptation in health and disease.

Extracellular matrices (ECMs) are dynamic 3D macromolecular networks that exhibit structural characteristics and composition specific to different tissues, serving various biomechanical and regulatory functions. The interactions between ECM macromolecules such as collagen, elastin, glycosaminoglycans (GAGs), proteoglycans (PGs), fibronectin, and laminin, along with matrix effectors and water, contribute to the unique cellular and tissue functional properties during organ development, tissue homoeostasis, remodeling, disease development, and progression. Cells adapt to environmental changes by adjusting the composition and array of ECM components. ECMs, forming the 3D bioscaffolds of our body, provide mechanical support for tissues and organs and respond to the environmental variables influencing growth and final adult body shape in mammals. Different cell types displaydistinct adaptations to the respective ECM environments. ECMs regulate biological processes by controlling the diffusion of infections and inflammations, sensing and adapting to external stimuli and gravity from the surrounding habitat, and, in the context of cancer, interplaying with and regulating cancer cell invasion and drug resistance. Alterations in the ECM composition in pathological conditions drive adaptive responses of cells and could therefore result in abnormal cell behavior and tissue dysfunction. Understanding the biomechanical functionality, adaptation, and roles of distinct ECMs is essential for research on various pathologies, including cancer progression and multidrug resistance, which is of crucial importance for developing targeted therapies. In this Viewpoint article, we critically present and discuss specific biomechanical functions of ECMs and regulatory adaptation mechanisms in both health and disease, with a particular focus on cancer progression.

Structure, catalysis, chitin transport, and selective inhibition of chitin synthase

Chitin is one of the most abundant natural biopolymers and serves as a critical structural component of extracellular matrices, including fungal cell walls and insect exoskeletons. As a linear polymer of β-(1,4)-linked N-acetylglucosamine, chitin is synthesized by chitin synthases, which are recognized as targets for antifungal and anti-insect drugs. In this study, we determine seven different cryo-electron microscopy structures of a Saccharomyces cerevisiae chitin synthase in the absence and presence of glycosyl donor, acceptor, product, or peptidyl nucleoside inhibitors. Combined with functional analyses, these structures show how the donor and acceptor substrates bind in the active site, how substrate hydrolysis drives self-priming, how a chitin-conducting transmembrane channel opens, and how peptidyl nucleoside inhibitors inhibit chitin synthase. Our work provides a structural basis for understanding the function and inhibition of chitin synthase.

#5649 HEPARANASE OVEREXPRESSION MODIFIES PODOCYTE MOTILITY

Abstract Background and Aims Heparanase is an endo-β-d-glucuronidase that degrades heparan sulfate side chains, which are essential components of extracellular matrices and cell surfaces, including in the kidney filtration apparatus, the glomerulus. Upregulation of heparanase in glomerular diseases (GDs) was demonstrated in experimental models of GDs and in humans. Using transgenic mice overexpressing the human heparanase gene, we recently showed that heparanase reduced proteinuria and preserved the glomerular filtration barrier (GFB) after Adriamycin-induced injury. Furthermore, heparanase improved survival of key GFB cells, the podocytes and enhanced their autophagic flux both in vitro and in vivo. Here, we aimed to study the potential role of heparanase on podocyte locomotion and adhesion. Methods We utilized immortalized human podocyte cell line AB8/13 (a kind gift of Prof. Moin Saleem, Bristol, UK) as an experimental platform. Cells were infected with pLenti6/V5-DEST carrying the heparanase gene construct (H) or control empty vector (V) and were allowed to differentiate for 14 days. To induce injury, differentiated podocytes were treated with Adriamycin (0.5 μg/mL), mimicking Adriamycin nephropathy, an established experimental model for progressive proteinuric GDs. For readouts, we used scratch assay, RT-qPCR, Western blot (WB) and immunofluorescence (IF) analyses. Results The in vitro scratch assay showed that differentiated (H) podocytes migrated at a slower rate compared with control (V) podocytes, both at baseline and after a 12-hour treatment with Adriamycin. Hence, we hypothesized that heparanase may alter podocyte adhesion properties. Indeed, IF staining of differentiated (H) podocytes exhibited an increase in focal contacts containing vinculin compared with control (V) cells treated with Adriamycin. Of note, we observed no differences in vinculin abundance by WB, suggesting that heparanase mediates the active form of vinculin. Moreover, among the integrins, we noticed temporal upregulation of ITGB1 transcription, as early as two hours after Adriamycin treatment, in (H) compared with control (V) podocytes (P = 0.032). Conclusions Collectively, our results suggest that in response to Adriamycin injury, constitutive heparanase overexpression could stabilize podocyte focal adhesions and control motility. Although further research is needed, improving the anchoring of podocytes over the basement membrane may provide an additional cellular mechanism by which heparanase conferred protection against Adriamycin toxicity.

Homozygous splice variant (c.1741-6G>A) of the COL6A1 gene in three patients with Ullrich congenital muscular dystrophy

The three major collagen VI genes: COL6A1, COL6A2, and COL6A3 encode microfibrillar components of extracellular matrices in multiple tissues including muscles and tendons. Pathogenic variants in the collagen VI genes cause collagen VI-related dystrophies representing a continuum of conditions from Bethlem myopathy at the milder end to Ullrich congenital muscular dystrophy at the more severe end. Here we describe a pathogenic variant in the COL6A1 gene (NM_001848.3; c.1741-6G>A) found in homozygosity in three patients with Ullrich congenital muscular dystrophy. The patients suffered from severe muscle impairment characterised by proximal weakness, distal hyperlaxity, joint contractures, wheelchair-dependency, and use of nocturnal non-invasive ventilation. The pathogenicity was verified by RNA analyses showing that the variant induced aberrant splicing leading to a frameshift and loss of function. The analyses were in line with immunocytochemistry studies of patient-derived skin fibroblasts and muscle tissue demonstrating impaired secretion of collagen VI into the extracellular matrix. Thereby, we add the variant c.1741-6G>A to the list of pathogenic, recessive, splice variants in COL6A1 causing Ullrich congenital muscular dystrophy. The variant is listed in ClinVar as of “uncertain significance” and “likely benign” and may presumably have been overlooked in other patients.

Fasciola hepatica juveniles interact with the host fibrinolytic system as a potential early-stage invasion mechanism.

The trematode Fasciola hepatica is the most widespread causative agent of fasciolosis, a parasitic disease that mainly affects humans and ruminants worldwide. During F. hepatica infection, newly excysted juveniles (FhNEJ) emerge in the duodenum of the mammalian host and migrate towards their definitive location, the intra-hepatic biliary ducts. Understanding how F. hepatica traverses the intestinal wall and migrates towards the liver is pivotal for the development of more successful strategies against fasciolosis. The central enzyme of the mammalian fibrinolytic system is plasmin, a serine protease whose functions are exploited by a number of parasite species owing to its broad spectrum of substrates, including components of tissue extracellular matrices. The aim of the present work is to understand whether FhNEJ co-opt the functions of their host fibrinolytic system as a mechanism to facilitate trans-intestinal migration. A tegument-enriched antigenic extract of FhNEJ (FhNEJ-Teg) was obtained in vitro, and its capability to bind the zymogen plasminogen (PLG) and enhance its conversion to the active protease, plasmin, were analyzed by a combination of enzyme-linked immunosorbent, chromogenic and immunofluorescence assays. Additionally, PLG-binding proteins in FhNEJ-Teg were identified by bidimensional electrophoresis coupled to mass spectrometry analysis, and the interactions were validated using FhNEJ recombinant proteins. Our results show that FhNEJ-Teg contains proteins that bind PLG and stimulate its activation to plasmin, which could facilitate the traversal of the intestinal wall by FhNEJ and contribute to the successful establishment of the parasite within its mammalian host. Altogether, our findings contribute to a better understanding of host-parasite relationships during early fasciolosis and may be exploited from a pharmacological and/or immunological perspective for the development of treatment and control strategies against this global disease.

Abstract 3140: Computational modeling of stromal-immune cell interactions in triple-negative breast cancer

Abstract Breast cancer is the most common cancer type in women worldwide, and it represents the second most common cause of cancer deaths. Compared with other breast cancer subtypes, triple-negative breast cancer (TNBC) has the worst prognosis. The tumor microenvironment (TME) of TNBC is a complex ecosystem, characterized by the dynamic interactions between stromal, immune, extracellular matrices (ECM), and cancer cells. Understanding the fibroblasts as a heterogeneous population with pleiotropic actions on TME, mediated by ECM formation and interactions with immune cells, is necessary to develop approaches to interfere with the loss of ECM homeostasis, promote immunity, and improve the outcome of concomitant therapeutic approaches in TNBC and other cancer types. Our recent studies suggested distinct fibroblast sub cell types of varied biosynthesis of ECM components in the TME of TNBC, which have significant associations with the infiltration and activity of immune cells. In this study, we developed advanced computational methods to characterize the role of fibroblast sub cell types, their functional variations, and stromal-immune cell interactions in TNBC, by integrative analysis of tissue, single-cell, and spatial multi-omics data. We hypothesized that the genes involved in sub cell types and functional variations of fibroblast cells may form distinct data structures in omics data, which are identifiable by carefully designed pattern recognition methods. We also hypothesized that different subtypes and functional activities of fibroblast cells lead to varied ECM formations, metabolic shifts, and affect the infiltration and functions of immune cells, which could be identified as the spatial regions with distinct expression changes of stromal and immune marker genes.We first reconstructed TNBC TME context-specific gene sets of fibroblast sub cell types and functions. We assemble a series of computational methods including tissue data deconvolution, functional module detection on scRNA-seq data, and metabolic flux analysis into an integrative data analysis framework to characterize fibroblast cells and their functions in the TME of TNBC and reconstruct context-specific pathways of fibroblast sub cell types and functions. We further detected spatially dependent ECM formation and stromal-immune cell interactions in TNBC by using spatial resolved transcriptomics data. We observed spatially dependent variations of (1) sub cell type and cell type-specific functions, and (2) stromal-immune cell interactions, in the TME of TNBC. Citation Format: Yuhui Wei, Haiqi Zhu, Xiao Wang, Xinyu Zhou, Jia Wang, Tingbo Guo, Pengtao Dang, Sha Cao, Chi Zhang. Computational modeling of stromal-immune cell interactions in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3140.

Nanocomposite Hydrogels as Functional Extracellular Matrices

Over recent years, nano-engineered materials have become an important component of artificial extracellular matrices. On one hand, these materials enable static enhancement of the bulk properties of cell scaffolds, for instance, they can alter mechanical properties or electrical conductivity, in order to better mimic the in vivo cell environment. Yet, many nanomaterials also exhibit dynamic, remotely tunable optical, electrical, magnetic, or acoustic properties, and therefore, can be used to non-invasively deliver localized, dynamic stimuli to cells cultured in artificial ECMs in three dimensions. Vice versa, the same, functional nanomaterials, can also report changing environmental conditions-whether or not, as a result of a dynamically applied stimulus-and as such provide means for wireless, long-term monitoring of the cell status inside the culture. In this review article, we present an overview of the technological advances regarding the incorporation of functional nanomaterials in artificial extracellular matrices, highlighting both passive and dynamically tunable nano-engineered components.

Inhibitory machinery for the functional dystroglycan glycosylation.

Dystroglycan (DG), a muscular transmembrane protein, plays a critical role in transducing extracellular matrix-derived signals to the cytoskeleton and provides physical strength to skeletal muscle cell membranes. The extracellular domain of DG, α-DG, displays unique glycosylation patterns. Fully functional glycosylation is required for this domain to interact with components of extracellular matrices, including laminin. One of the unique sugar compositions found in such functional glycans on DG is two ribitol phosphates that are transferred by the sequential actions of fukutin (FKTN) and fukutin-related protein (FKRP), which use CDP-ribitol as a donor substrate. These are then further primed for matriglycan biosynthesis. A recent in vitro study reported that glycerol phosphate could be similarly added to α-DG by FKTN and FKRP if they used CDP-glycerol (CDP-Gro) as a donor substrate. However, the physiological relevance of these findings remains elusive. Imae et al. addressed the knowledge gap regarding whether CDP-Gro is present in mammals and how CDP-Gro is synthesized and functions in mammals.

A dynamic interplay between chitin synthase and the proteins Expansion/Rebuf reveals that chitin polymerisation and translocation are uncoupled in Drosophila

Chitin is a highly abundant polymer in nature and a principal component of apical extracellular matrices in insects. In addition, chitin has proved to be an excellent biomaterial with multiple applications. In spite of its importance, the molecular mechanisms of chitin biosynthesis and chitin structural diversity are not fully elucidated yet. To investigate these issues, we use Drosophila as a model. We previously showed that chitin deposition in ectodermal tissues requires the concomitant activities of the chitin synthase enzyme Kkv and the functionally interchangeable proteins Exp and Reb. Exp/Reb are conserved proteins, but their mechanism of activity during chitin deposition has not been elucidated yet. Here, we carry out a cellular and molecular analysis of chitin deposition, and we show that chitin polymerisation and chitin translocation to the extracellular space are uncoupled. We find that Kkv activity in chitin translocation, but not in polymerisation, requires the activity of Exp/Reb, and in particular of its conserved Nα-MH2 domain. The activity of Kkv in chitin polymerisation and translocation correlate with Kkv subcellular localisation, and in absence of Kkv-mediated extracellular chitin deposition, chitin accumulates intracellularly as membrane-less punctae. Unexpectedly, we find that although Kkv and Exp/Reb display largely complementary patterns at the apical domain, Exp/Reb activity nonetheless regulates the topological distribution of Kkv at the apical membrane. We propose a model in which Exp/Reb regulate the organisation of Kkv complexes at the apical membrane, which, in turn, regulates the function of Kkv in extracellular chitin translocation.

Proteoglycans Determine the Dynamic Landscape of EMT and Cancer Cell Stemness.

Proteoglycans (PGs) are pivotal components of extracellular matrices, involved in a variety of processes such as migration, invasion, morphogenesis, differentiation, drug resistance, and epithelial-to-mesenchymal transition (EMT). Cellular plasticity is a crucial intermediate phenotypic state acquired by cancer cells, which can modulate EMT and the generation of cancer stem cells (CSCs). PGs affect cell plasticity, stemness, and EMT, altering the cellular shape and functions. PGs control these functions, either by direct activation of signaling cascades, acting as co-receptors, or through regulation of the availability of biological compounds such as growth factors and cytokines. Differential expression of microRNAs is also associated with the expression of PGs and their interplay is implicated in the fine tuning of cancer cell phenotype and potential. This review summarizes the involvement of PGs in the regulation of EMT and stemness of cancer cells and highlights the molecular mechanisms.

Simple synthesis of soft, tough, and cytocompatible biohybrid composites

Collagen is the most abundant component of mammalian extracellular matrices. As such, the development of materials that mimic the biological and mechanical properties of collagenous tissues is an enduring goal of the biomaterials community. Despite the development of molded and 3D printed collagen hydrogel platforms, their use as biomaterials and tissue engineering scaffolds is hindered by either low stiffness and toughness or processing complexity. Here, we demonstrate the development of stiff and tough biohybrid composites by combining collagen with a zwitterionic hydrogel through simple mixing. This combination led to the self-assembly of a nanostructured fibrillar network of collagen that was ionically linked to the surrounding zwitterionic hydrogel matrix, leading to a composite microstructure reminiscent of soft biological tissues. The addition of 5-15 mg mL-1 collagen and the formation of nanostructured fibrils increased the elastic modulus of the composite system by 40% compared to the base zwitterionic matrix. Most notably, the addition of collagen increased the fracture energy nearly 11-fold ([Formula: see text] 180 J m-2) and clearly delayed crack initiation and propagation. These composites exhibit elastic modulus ([Formula: see text] 0.180 MJ) and toughness ([Formula: see text]0.617 MJ m-3) approaching that of biological tissues such as articular cartilage. Maintenance of the fibrillar structure of collagen also greatly enhanced cytocompatibility, improving cell adhesion more than 100-fold with >90% cell viability.

Matrix-bound Cyr61/CCN1 is required to retain the properties of the bone marrow mesenchymal stem cell niche but is depleted with aging

Previously, we showed that extracellular matrices (ECMs), produced ex vivo by various types of stromal cells, direct bone marrow mesenchymal stem cells (BM-MSCs) in a tissue-specific manner and recapitulate physiologic changes characteristic of the aging microenvironment. In particular, BM-MSCs obtained from elderly donors and cultured on ECM produced by young BM stromal cells showed improved quantity, quality and osteogenic differentiation. In the present study, we searched for matrix components that are required for a functional BM-MSC niche by comparing ECMs produced by BM stromal cells from “young” (≤25 y/o) versus “elderly” (≥60 y/o) donors. With increasing donor age, ECM fibrillar organization and mechanical integrity deteriorated, along with the ability to promote BM-MSC proliferation and responsiveness to growth factors. Proteomic analyses revealed that the matricellular protein, Cyr61/CCN1, was present in young, but undetectable in elderly, BM-ECM. To assess the role of Cyr61 in the BM-MSC niche, we used genetic methods to down-regulate the incorporation of Cyr61 during production of young ECM and up-regulate its incorporation in elderly ECM. The results showed that Cyr61-depleted young ECM lost the ability to promote BM-MSC proliferation and growth factor responsiveness. However, up-regulating the incorporation of Cyr61 during synthesis of elderly ECM restored its ability to support BM-MSC responsiveness to osteogenic factors such as BMP-2 and IGF-1. We next examined aging bone and compared bone mineral density and Cyr61 content of L4-L5 vertebral bodies in “young” (9–11 m/o) and “elderly” (21–33 m/o) mice. Our analyses showed that low bone mineral density was associated with decreased amounts of Cyr61 in osseous tissue of elderly versus young mice. Our results strongly demonstrate a novel role for ECM-bound Cyr61 in the BM-MSC niche, where it is responsible for retention of BM-MSC proliferation and growth factor responsiveness, while depletion of Cyr61 from the BM niche contributes to an aging-related dysregulation of BM-MSCs. Our results also suggest new potential therapeutic targets for treating age-related bone loss by restoring specific ECM components to the stem cell niche.

Spatial distribution and network morphology of epicardial, endocardial, interstitial, and Purkinje cell-associated elastin fibers in porcine left ventricle.

Cardiac extracellular matrices (ECM) play crucial functional roles in cardiac biomechanics. Previous studies have mainly focused on collagen, the major structural ECM in heart wall. The role of elastin in cardiac mechanics, however, is poorly understood. In this study, we investigated the spatial distribution and microstructural morphologies of cardiac elastin in porcine left ventricles. We demonstrated that the epicardial elastin network had location- and depth-dependency, and the overall epicardial elastin fiber mapping showed certain correlation with the helical heart muscle fiber architecture. When compared to the epicardial layer, the endocardial layer was thicker and has a higher elastin-collagen ratio and a denser elastin fiber network; moreover, the endocardial elastin fibers were finer and more wavy than the epicardial elastin fibers, all suggesting various interface mechanics. The myocardial interstitial elastin fibers co-exist with the perimysial collagen to bind the cardiomyocyte bundles; some of the interstitial elastin fibers showed a locally aligned, hinge-like structure to connect the adjacent cardiomyocyte bundles. This collagen-elastin combination reflects an optimal design in which the collagen provides mechanical strength and elastin fibers facilitate recoiling during systole. Moreover, cardiac elastin fibers, along with collagen network, closely associated with the Purkinje cells, indicating that this ECM association could be essential in organizing cardiac Purkinje cells into “fibrous” and “branching” morphologies and serving as a protective feature when Purkinje fibers experience large deformations in vivo. In short, our observations provide a structural basis for future in-depth biomechanical investigations and biomimicking of this long-overlooked cardiac ECM component.

The properties of the modified fish collagen peptide hydrogel

Collagen hydrogel is an attractive material for biomedical applications as it is the most abundant protein in mammalian tissues and is the main component of natural extracellular matrices. The study aims to identify the hydrogel's performance prepared by UV and heat cure and investigate the effect of graphene oxide (GO) on the properties of heat cure hydrogel. The hydrogels were prepared with two different curing methods using Irgacure2959 and potassium persulfate as crosslinkers in this work. GO acts as filler was added in the hydrogel to form a composite hydrogel. The hydrogels were characterized using compression test, swelling test, and thermogravimetric analysis (TGA). This study found that the heat-cured hydrogel exhibited higher compression properties than that prepared by the UV curing method. The results follow the swelling test. Adding GO in the heat-cured hydrogel improved the compression strength of composite hydrogel by 56% compared to the unfilled hydrogel. The thermal stability of hydrogel showed two decomposition steps, one in the range of 100–200 °C related to the loss of water and another in the range of 300–400 °C associated with degradation of the collagen structure. Results showed that the GO composite has higher thermal stability than an unfilled hydrogel.

Gardeniae Fructus Attenuates Thioacetamide-Induced Liver Fibrosis in Mice via Both AMPK/SIRT1/NF-κB Pathway and Nrf2 Signaling.

Liver fibrosis, which means a sort of the excessive accumulation of extracellular matrices (ECMs) components through the liver tissue, is considered as tissue repair or wound-healing status. This pathological stage potentially leads to cirrhosis, if not controlled, it progressively results in hepatocellular carcinoma. Herein, we investigated the pharmacological properties and underlying mechanisms of Gardeniae Fructus (GF) against thioacetamide (TAA)-induced liver fibrosis of mice model. GF not only attenuated hepatic tissue oxidation but also improved hepatic inflammation. We further confirmed that GF led to ameliorating liver fibrosis by ECMs degradations. Regarding the possible underlying mechanism of GF, we observed GF regulated epigenetic regulator, Sirtuin 1 (SIRT1), in TAA-injected liver tissue. These alterations were well supported by SIRT1 related signaling pathways through regulations of its downstream proteins including, AMP-activated protein kinase (AMPK), p47phox, NADPH oxidase 2, nuclear factor erythroid 2–related factor 2 (Nrf2), and heme oxygenase-1, respectively. To validate the possible mechanism of GF, we used HepG2 cells with hydrogen peroxide treated oxidative stress and chronic exposure conditions via deteriorations of cellular SIRT1. Moreover, GF remarkably attenuated ECMs accumulations in transforming growth factor–β1-induced LX-2 cells relying on the SIRT1 existence. Taken together, GF attenuated liver fibrosis through AMPK/SIRT1 pathway as well as Nrf2 signaling cascades. Therefore, GF could be a clinical remedy for liver fibrosis patients in the future.

Inherited Proteoglycan Biosynthesis Defects—Current Laboratory Tools and Bikunin as a Promising Blood Biomarker

Proteoglycans consist of proteins linked to sulfated glycosaminoglycan chains. They constitute a family of macromolecules mainly involved in the architecture of organs and tissues as major components of extracellular matrices. Some proteoglycans also act as signaling molecules involved in inflammatory response as well as cell proliferation, adhesion, and differentiation. Inborn errors of proteoglycan metabolism are a group of orphan diseases with severe and irreversible skeletal abnormalities associated with multiorgan impairments. Identifying the gene variants that cause these pathologies proves to be difficult because of unspecific clinical symptoms, hardly accessible functional laboratory tests, and a lack of convenient blood biomarkers. In this review, we summarize the molecular pathways of proteoglycan biosynthesis, the associated inherited syndromes, and the related biochemical screening techniques, and we focus especially on a circulating proteoglycan called bikunin and on its potential as a new biomarker of these diseases.

Effect of glycosaminoglycan structure on all-trans-retinoic acid-induced neural differentiation of P19 embryonal carcinoma cells

Glycosaminoglycan polysaccharides are components of animal extracellular matrices and regulate cell functions based on their various sulfation and epimerization pattern structures. The present study aimed to find glycosaminoglycan structures to promote neural differentiation. We investigated the effect of exogenous glycosaminoglycans with well-defined structures on the all-trans-retinoic acid-induced neural differentiation of P19 embryonal carcinoma cells, which is an ideal model culture system for studying neural differentiation. We found that chondroitin sulfate E and heparin, but not any other glycosaminoglycans, upregulated the expressions of neural specific markers but not a grail specific marker. Chondroitin sulfate E was suggested to function during spheroid formation, however, equimolar concentration of its oligosaccharide did not show promotive effect on the neural differentiation. Another finding was that hyaluronan oligosaccharide mixture markedly downregulated the expressions of a myelin specific marker. These findings suggested that the specific sulfation pattern and/or chain length of exogenous added glycosaminoglycan is important to regulate neural differentiation and myelination.

Renal Regeneration: The Role of Extracellular Matrix and Current ECM-Based Tissue Engineered Strategies.

Natural extracellular matrices (ECM) are currently being studied as an alternative source for organ transplantation or as new solutions to treat kidney injuries, which can evolve to end-stage renal disease, a life devastating condition. This paper provides an overview on the current knowledge in kidney ECM and its usefulness on future investigations. The composition and structure of kidney ECM is herein associated with its intrinsic capacity of remodeling and repair after insult. Moreover, it provides a deeper insight on altered ECM components during disease. The use of decellularized kidney matrices is discussed in the second part of the review, with emphasis on how these matrices contribute to tissue-specific differentiation of embryonic, pluripotent, and other stem cells. The evolution on the field toward different uses of xenogeneic ECM as a biological scaffold material is discussed, namely the major outcomes on whole kidney recellularization and its in vivo implantation. At last, the recent literature on the use of processed kidney decellularized ECM to produce diverse biomaterial substrates, such as hydrogels, membranes, and bioinks are reviewed, with emphasis on future perspectives of its translation into the clinic.