Platelet-derived growth factor stimulates the formation of versican-hyaluronan aggregates and pericellular matrix expansion in arterial smooth muscle cells

Versican controlled by Lmx1b regulates hyaluronate density and hydration for semicircular canal morphogenesis

During inner ear semicircular canal morphogenesis in zebrafish, patterned canal-genesis zones express genes for extracellular matrix component synthesis. These include hyaluronan and the hyaluronan-binding chondroitin sulfate proteoglycan Versican, which are abundant in the matrices of many developing organs. Charged hyaluronate polymers play a key role in canal morphogenesis through osmotic swelling. However, the developmental factor(s) that control the synthesis of the matrix components and regulation of hyaluronate density and swelling are unknown. Here, we identify the transcription factor, Lmx1b, as a positive transcriptional regulator of hyaluronan, Versican, and chondroitin synthesis genes crucial for canal morphogenesis. We show that Versican regulates hyaluronan density through its protein core, whereas the charged chondroitin side chains contribute to the osmotic swelling of hyaluronate. Versican-tuned properties of hyaluronate matrices may be a broadly used mechanism in morphogenesis with important implications for understanding diseases where these matrices are impaired, and for hydrogel engineering for tissue regeneration.

Inorganic Phosphate-Induced Extracellular Vesicles from Vascular Smooth Muscle Cells Contain Elevated Levels of Hyaluronic Acid, Which Enhance Their Interaction with Very Small Superparamagnetic Iron Oxide Particles

Patients with chronic kidney disease (CKD) have a high prevalence of hyperphosphatemia, where uremic toxins like inorganic phosphate (Pi) induce a cardiovascular remodeling. Related disorders like atherosclerosis bear the risk of increased morbidity and mortality. We previously found that Pi stimulates the synthesis and sulfation of the negatively charged glycosaminoglycans (GAGs) heparan sulfate and chondroitin sulfate in vascular smooth muscle cells (VSMC). Similar GAG alterations were detected in VSMC-derived exosome-like extracellular vesicles (EV). These EV showed a strong interaction with very small superparamagnetic iron oxide particles (VSOP), which are used as imaging probes for experimental magnetic resonance imaging (MRI). Hyaluronic acid (HA) represents another negatively charged GAG which is supposed to function as binding motif for VSOP as well. We investigated the effects of Pi on the amounts of HA in cells and EV and studied the HA-dependent interaction between VSOP with cells and EV. Rat VSMC were treated with elevated concentrations of Pi. CKD in rats was induced by adenine feeding. EV were isolated from culture supernatants and rat plasma. We investigated the role of HA in binding VSOP to cells and EV via cell-binding studies, proton relaxometry, and analysis of cellular signaling, genes, proteins, and HA contents. Due to elevated HA contents, VSMC and EV showed an increased interaction with VSOP after Pi stimulation. Amongst others, Pi induced hyaluronan synthase (HAS)2 expression and activation of the Wnt pathway in VSMC. An alternative upregulation of HA by iloprost and an siRNA-mediated knockdown of HAS2 confirmed the importance of HA in cells and EV for VSOP binding. The in vitro-derived data were validated by analyses of plasma-derived EV from uremic rats. In conclusion, the inorganic uremic toxin Pi induces HA synthesis in cells and EV, which leads to an increased interaction with VSOP. HA might therefore be a potential molecular target structure for improved detection of pathologic tissue changes secondary to CKD like atherosclerosis or cardiomyopathy using EV, VSOP and MRI.

Versican accumulation drives Nos2 induction and aortic disease in Marfan syndrome via Akt activation

Thoracic aortic aneurysm and dissection (TAAD) is a life-threatening condition associated with Marfan syndrome (MFS), a disease caused by fibrillin-1 gene mutations. While various conditions causing TAAD exhibit aortic accumulation of the proteoglycans versican (Vcan) and aggrecan (Acan), it is unclear whether these ECM proteins are involved in aortic disease. Here, we find that Vcan, but not Acan, accumulated in Fbn1C1041G/+ aortas, a mouse model of MFS. Vcan haploinsufficiency protected MFS mice against aortic dilation, and its silencing reverted aortic disease by reducing Nos2 protein expression. Our results suggest that Acan is not an essential contributor to MFS aortopathy. We further demonstrate that Vcan triggers Akt activation and that pharmacological Akt pathway inhibition rapidly regresses aortic dilation and Nos2 expression in MFS mice. Analysis of aortic tissue from MFS human patients revealed accumulation of VCAN and elevated pAKT-S473 staining. Together, these findings reveal that Vcan plays a causative role in MFS aortic disease in vivo by inducing Nos2 via Akt activation and identify Akt signaling pathway components as candidate therapeutic targets.

An immunohistochemical study of matrix components in primary and secondary cartilages of embryonic chick skull

OBJECTIVES

This study aimed to compare the extracellular matrix of primary cartilage with the secondary cartilage of chicks using immunohistochemical analyses in order to understand the features of chick secondary chondrogenesis.

METHODS

Immunohistochemical analysis was performed on the extracellular matrix of quadrate (primary), squamosal, surangular, and anterior pterygoid secondary cartilages using various antibodies targeting the extracellular matrix of cartilage and bone.

RESULTS

The localization of collagen types I, II, and X, versican, aggrecan, hyaluronan, link protein, and tenascin-C was identified in the quadrate cartilage, with variations within and between the regions. Newly formed squamosal and surangular secondary cartilages showed simultaneous immunoreactivity for all molecules investigated. However, collagen type X immunoreactivity was not observed, and there was weak immunoreactivity for versican and aggrecan in the anterior pterygoid secondary cartilage.

CONCLUSIONS

The immunohistochemical localization of extracellular matrix in the quadrate (primary) cartilage was comparable to that of long bone (primary) cartilage in mammals. The fibrocartilaginous nature and rapid differentiation into hypertrophic chondrocytes, which are known structural features of secondary cartilage, were confirmed in the extracellular matrix of squamosal and surangular secondary cartilages. Furthermore, these tissues appear to undergo developmental processes similar to those in mammals. However, the anterior pterygoid secondary cartilage exhibited unique features that differed from primary and other secondary cartilages, suggesting it is formed through a distinct developmental process.

V3: an enigmatic isoform of the proteoglycan versican

V3 is an isoform of the extracellular matrix (ECM) proteoglycan (PG) versican generated through alternative splicing of the versican gene such that the two major exons coding for sequences in the protein core that support chondroitin sulfate (CS) glycosaminoglycan (GAG) chain attachment are excluded. Thus, versican V3 isoform carries no GAGs. A survey of PubMed reveals only 50 publications specifically on V3 versican, so it is a very understudied member of the versican family, partly because to date there are no antibodies that can distinguish V3 from the CS-carrying isoforms of versican, that is, to facilitate functional and mechanistic studies. However, a number of in vitro and in vivo studies have identified the expression of the V3 transcript during different phases of development and in disease, and selective overexpression of V3 has shown dramatic phenotypic effects in "gain and loss of function" studies in experimental models. Thus, we thought it would be useful and instructive to discuss the discovery, characterization, and the putative biological importance of the enigmatic V3 isoform of versican.

The Contribution of Vascular Proteoglycans to Atherothrombosis: Clinical Implications

The vascular extracellular matrix (ECM) produced by endothelial and smooth muscle cells is composed of collagens and glycoproteins and plays an integral role in regulating the structure and function of the vascular wall. Alteration in the expression of these proteins is associated with endothelial dysfunction and has been implicated in the development and progression of atherosclerosis. The ECM composition of atherosclerotic plaques varies depending on plaque phenotype and vulnerability, with distinct differences observed between ruptured and erodes plaques. Moreover, the thrombi on the exposed ECM are diverse in structure and composition, suggesting that the best antithrombotic approach may differ depending on plaque phenotype. This review provides a comprehensive overview of the role of proteoglycans in atherogenesis and thrombosis. It discusses the differential expression of the proteoglycans in different plaque phenotypes and the potential impact on platelet function and thrombosis. Finally, the review highlights the importance of this concept in developing a targeted approach to antithrombotic treatments to improve clinical outcomes in cardiovascular disease.

Identification and validation of biomarkers for epithelial-mesenchymal transition-related cells to estimate the prognosis and immune microenvironment in primary gastric cancer by the integrated analysis of single-cell and bulk RNA sequencing data

BACKGROUND

The epithelial-mesenchymal transition (EMT) is associated with gastric cancer (GC) progression and immune microenvironment. To better understand the heterogeneity underlying EMT, we integrated single-cell RNA-sequencing (scRNA-seq) data and bulk sequencing data from GC patients to evaluate the prognostic utility of biomarkers for EMT-related cells (ERCs), namely, cancer-associated fibroblasts (CAFs) and epithelial cells (ECs).

METHODS

scRNA-seq data from primary GC tumor samples were obtained from the Gene Expression Omnibus (GEO) database to identify ERC marker genes. Bulk GC datasets from the Cancer Genome Atlas (TCGA) and GEO were used as training and validation sets, respectively. Differentially expressed markers were identified from the TCGA database. Univariate Cox, least-absolute shrinkage, and selection operator regression analyses were performed to identify EMT-related cell-prognostic genes (ERCPGs). Kaplan-Meier, Cox regression, and receiver-operating characteristic (ROC) curve analyses were adopted to evaluate the prognostic utility of the ERCPG signature. An ERCPG-based nomogram was constructed by integrating independent prognostic factors. Finally, we evaluated the correlations between the ERCPG signature and immune-cell infiltration and verified the expression of ERCPG prognostic signature genes by in vitro cellular assays.

RESULTS

The ERCPG signature was comprised of seven genes (COL4A1, F2R, MMP11, CAV1, VCAN, FKBP10, and APOD). Patients were divided into high- and low-risk groups based on the ERCPG risk scores. Patients in the high-risk group showed a poor prognosis. ROC and calibration curves suggested that the ERCPG signature and nomogram had a good prognostic utility. An immune cell-infiltration analysis suggested that the abnormal expression of ERCPGs induced the formation of an unfavorable tumor immune microenvironment. In vitro cellular assays showed that ERCPGs were more abundantly expressed in GC cell lines compared to normal gastric tissue cell lines.

CONCLUSIONS

We constructed and validated an ERCPG signature using scRNA-seq and bulk sequencing data from ERCs of GC patients. Our findings support the estimation of patient prognosis and tumor treatment in future clinical practice.

VCAN Hypomethylation and Expression as Predictive Biomarkers of Drug Sensitivity in Upper Urinary Tract Urothelial Carcinoma

Versican (VCAN), also known as extracellular matrix proteoglycan 2, has been suggested as a potential biomarker in cancers. Previous research has found that VCAN is highly expressed in bladder cancer. However, its role in predicting outcomes for patients with upper urinary tract urothelial cancer (UTUC) is not well understood. In this study, we collected tissues from 10 patients with UTUC, including 6 with and 4 without lymphovascular invasion (LVI), a pathological feature that plays a significant role in determining metastasis. Results from RNA sequencing revealed that the most differentially expressed genes were involved in extracellular matrix organization. Using the TCGA database for clinical correlation, VCAN was identified as a target for study. A chromosome methylation assay showed that VCAN was hypomethylated in tumors with LVI. In our patient samples, VCAN expression was also found to be high in UTUC tumors with LVI. In vitro analysis showed that knocking down VCAN inhibited cell migration but not proliferation. A heatmap analysis also confirmed a significant correlation between VCAN and migration genes. Additionally, silencing VCAN increased the effectiveness of cisplatin, gemcitabine and epirubicin, thus providing potential opportunities for clinical application.

Association of Collagen, Elastin, Glycosaminoglycans, and Macrophages With Tissue Ultimate Material Strength and Stretch in Human Thoracic Aortic Aneurysms: A Uniaxial Tension Study

Fiber structures and pathological features, e.g., inflammation and glycosaminoglycan (GAG) deposition, are the primary determinants of aortic mechanical properties which are associated with the development of an aneurysm. This study is designed to quantify the association of tissue ultimate strength and extensibility with the structural percentage of different components, in particular, GAG, and local fiber orientation. Thoracic aortic aneurysm (TAA) tissues from eight patients were collected. Ninety-six tissue strips of thickened intima, media, and adventitia were prepared for uni-extension tests and histopathological examination. Area ratios of collagen, elastin, macrophage and GAG, and collagen fiber dispersion were quantified. Collagen, elastin, and GAG were layer-dependent and the inflammatory burden in all layers was low. The local GAG ratio was negatively associated with the collagen ratio (r2 = 0.173, p < 0.05), but positively with elastin (r2 = 0.037, p < 0.05). Higher GAG deposition resulted in larger local collagen fiber dispersion in the media and adventitia, but not in the intima. The ultimate stretch in both axial and circumferential directions was exclusively associated with elastin ratio (axial: r2 = 0.186, p = 0.04; circumferential: r2 = 0.175, p = 0.04). Multivariate analysis showed that collagen and GAG contents were both associated with ultimate strength in the circumferential direction, but not with the axial direction (collagen: slope = 27.3, GAG: slope = -18.4, r2 = 0.438, p = 0.002). GAG may play important roles in TAA material strength. Their deposition was found to be associated positively with the local collagen fiber dispersion and negatively with ultimate strength in the circumferential direction.

Mechanical and histological characteristics of aortic dissection tissues

AIMS

This study investigated the association between the macroscopic mechanical response of aortic dissection (AoD) flap, its fibre features, and patient physiological features and clinical presentations.

METHODS

Uniaxial test was performed with tissue strips in both circumferential and longitudinal directions from 35 patients with (AoD:CC) and without (AoD:w/oCC) cerebral/coronary complications, and 19 patients with rheumatic or valve-related heart diseases (RH). A Bayesian inference framework was used to estimate the expectation of material constants (C₁, D₁, and D₂) of the modified Mooney-Rivlin strain energy density function. Histological examination was used to visualise the elastin and collagen in the tissue strips and image processing was performed to quantify their area percentages, fibre misalignment and waviness.

RESULTS

The elastin area percentage was negatively associated with age (p = 0.008), while collagen increased about 6% from age 40 to 70 (p = 0.03). Elastin fibre was less dispersed and wavier in old patients and no significant association was found between patient age and collagen fibre dispersion or waviness. Features of fibrous microstructures, either elastin or collagen, were comparable between AoD:CC and AoD:w/oCC group. Elastin and collagen area percentages were positively correlated with C₁ and D₂, respectively, while the elastin and collagen waviness were negatively correlated with C₁ and D₂, respectively. Elastin dispersion was negatively correlated to D₂. Multivariate analysis showed that D₂ was an effective parameter which could differentiate patient groups with different age and clinical presentations, as well as the direction of tissue strip.

CONCLUSION

Fibre dispersion and waviness in the aortic dissection flap changed with patient age and clinical presentations, and these can be captured by the material constants in the strain energy density function.

STATEMENT OF SIGNIFICANCE

Aortic dissection (AoD) is a severe cardiovascular disease. Understanding the mechanical property of intimal flap is essential for its risk evaluation. In this study, mechanical testing and histology examination were combined to quantify the relationship between mechanical presentations and microstructure features. A Bayesian inference framework was employed to estimate the expectation of the material constants in the modified Mooney-Rivlin constitutive equation. It was found that fibre dispersion and waviness in the AoD flap changed with patient age and clinical presentations, and these could be captured by the material constants. This study firstly demonstrated that the expectation of material constants can be used to characterise tissue microstructures and differentiate patients with different clinical presentations.

Histological Evaluation of Restylane Lyft Used as a Scaffold for Dental Pulp Regeneration in Non-Infected Immature Teeth in Dogs

Commercially available hyaluronic acid dermal fillers used as a scaffold in regenerative endodontic procedures (REPs) have demonstrated attractive potentials. This study aimed to histologically evaluate the outcome of REPs using Restylane Lyft (HA) as a scaffold. REPs were performed on pulpless, immature roots in dogs (n = 69). The roots were divided into four groups: blood clot (BC), Restylane Lyft (BC + HA), negative control, and positive control. At 13 weeks postoperatively, hard tissue formation, vascularization, the presence of vascularized soft connective tissue and collagen fibers, the degree of inflammation within pulp spaces and/or periapical tissues, and apical closure were evaluated histologically. The vascularization and formation of loosely arranged collagen fibers within the regenerated soft connective tissues were observed significantly more in the BC+HA group (85% and 40%, respectively; p < 0.05) compared to the BC group (54.6% and 9.1%, respectively; p < 0.05). The degree of inflammation was significantly higher in the HA group than in the BC group; moderate to severe inflammatory cell infiltration was seen in 45% and 13.6% of the cases, respectively. The results of the present study suggest that Restylane Lyft combined with a blood clot used as a scaffold may improve the outcomes of REPs in non-infected, pulpless, immature teeth in dogs.

Densification: Hyaluronan Aggregation in Different Human Organs

Hyaluronan (HA) has complex biological roles that have catalyzed clinical interest in several fields of medicine. In this narrative review, we provide an overview of HA aggregation, also called densification, in human organs. The literature suggests that HA aggregation can occur in the liver, eye, lung, kidney, blood vessel, muscle, fascia, skin, pancreatic cancer and malignant melanoma. In all these organs, aggregation of HA leads to an increase in extracellular matrix viscosity, causing stiffness and organ dysfunction. Fibrosis, in some of these organs, may also occur as a direct consequence of densification in the long term. Specific imaging evaluation, such dynamic ultrasonography, elasto-sonography, elasto-MRI and T1ρ MRI can permit early diagnosis to enable the clinician to organize the treatment plan and avoid further progression of the pathology and dysfunction.

Targeting Versican as a Potential Immunotherapeutic Strategy in the Treatment of Cancer

A growing body of literature links events associated with the progression and severity of immunity and inflammatory disease with the composition of the tissue extracellular matrix as defined by the matrisome. One protein in the matrisome that is common to many inflammatory diseases is the large proteoglycan versican, whose varied function is achieved through multiple isoforms and post-translational modifications of glycosaminoglycan structures. In cancer, increased levels of versican are associated with immune cell phenotype, disease prognosis and failure to respond to treatment. Whether these associations between versican expression and tumour immunity are the result of a direct role in the pathogenesis of tumours is not clear. In this review, we have focused on the role of versican in the immune response as it relates to tumour progression, with the aim of determining whether our current understanding of the immunobiology of versican warrants further study as a cancer immunotherapy target.

Hyaluronan in skin wound healing: therapeutic applications

Hyaluronan is a vital constituent in effective skin wound healing. This polysaccharide is ubiquitous throughout the human body and has functional significance for tissue repair and remodelling. The importance of hyaluronan in the proliferative phase of healing is diverse, impacting on cell migration, proliferation, modification of the inflammatory response and on angiogenesis. As such, it holds therapeutic potential for a variety of clinical applications that range from facilitating effective wound healing to burns management and scarring. This overview of the multifaceted roles of hyaluronan considers its current applications to clinical practice in plastic surgery as well as the latest advances in research.

Helix-Loop-Helix Factor Id3 (Inhibitor of Differentiation 3): A Novel Regulator of Hyaluronan-Mediated Adipose Tissue Inflammation

OBJECTIVE

The aim of this study was to unravel mechanisms whereby deficiency of the transcription factor Id3 (inhibitor of differentiation 3) leads to metabolic dysfunction in visceral obesity. We investigated the impact of loss of Id3 on hyaluronic acid (HA) production by the 3 HAS isoenzymes (HA synthases; -1, -2, and -3) and on obesity-induced adipose tissue (AT) accumulation of proinflammatory B cells. Approach and Results: Male Id3-/- mice and respective wild-type littermate controls were fed a 60% high-fat diet for 4 weeks. An increase in inflammatory B2 cells was detected in Id3-/- epididymal AT. HA accumulated in epididymal AT of high-fat diet-fed Id3-/- mice and circulating levels of HA were elevated. Has2 mRNA expression was increased in epididymal AT of Id3-/- mice. Luciferase promoter assays showed that Id3 suppressed Has2 promoter activity, while loss of Id3 stimulated Has2 promoter activity. Functionally, HA strongly promoted B2 cell adhesion in the AT and on cultured vascular smooth muscle cells of Id3-/- mice, an effect sensitive to hyaluronidase.

CONCLUSIONS

Our data demonstrate that loss of Id3 increases Has2 expression in the epididymal AT, thereby promoting HA accumulation. In turn, elevated HA content promotes HA-dependent binding of B2 cells and an increase in the B2 cells in the AT, which contributes to AT inflammation.

Loss of versican and production of hyaluronan in lung epithelial cells are associated with airway inflammation during RSV infection

Airway inflammation is a critical feature of lower respiratory tract infections caused by viruses such as respiratory syncytial virus (RSV). A growing body of literature has demonstrated the importance of extracellular matrix changes such as the accumulation of hyaluronan (HA) and versican in the subepithelial space in promoting airway inflammation; however, whether these factors contribute to airway inflammation during RSV infection remains unknown. To test the hypothesis that RSV infection promotes inflammation via altered HA and versican production, we studied an ex vivo human bronchial epithelial cell (BEC)/human lung fibroblast (HLF) coculture model. RSV infection of BEC/HLF cocultures led to decreased hyaluronidase expression by HLFs, increased accumulation of HA, and enhanced adhesion of U937 cells as would be expected with increased HA. HLF production of versican was not altered following RSV infection; however, BEC production of versican was significantly downregulated following RSV infection. In vivo studies with epithelial-specific versican-deficient mice [SPC-Cre(+) Vcan-/-] demonstrated that RSV infection led to increased HA accumulation compared with control mice, which also coincided with decreased hyaluronidase expression in the lung. SPC-Cre(+) Vcan-/- mice demonstrated enhanced recruitment of monocytes and neutrophils in bronchoalveolar lavage fluid and increased neutrophils in the lung compared with SPC-Cre(-) RSV-infected littermates. Taken together, these data demonstrate that altered extracellular matrix accumulation of HA occurs following RSV infection and may contribute to airway inflammation. In addition, loss of epithelial expression of versican promotes airway inflammation during RSV infection further demonstrating that versican's role in inflammatory regulation is complex and dependent on the microenvironment.

A Role for HAPLN1 During Phenotypic Modulation of Human Lung Fibroblasts In Vitro

Hyaluronan and proteoglycan link protein 1 (HAPLN1) stabilizes interactions between two important extracellular matrix (ECM) macromolecules, versican and hyaluronan, which facilitate proliferation of fibroblasts and their conversion to myofibroblasts. However, the role of HAPLN1 in these events has not been studied. Using immunocytochemistry, cellular and ECM locations of HAPLN1 were evaluated in cultured human lung fibroblasts during proliferation and conversion to myofibroblasts. HAPLN1 localized to pericellular matrices, associating with both versican and hyaluronan in the ECM and on the cell surface. Nuclear and total HAPLN1 immunostaining increased after myofibroblast induction. Confocal microscopy showed HAPLN1 predominant in the ECM under cells while versican predominated above cells. Versican and HAPLN1 were also juxtaposed in columnar inclusions in the cytoplasm and nucleus. Nuclear HAPLN1 staining in interphase cells redistributed to the cytosol during mitosis. In the absence of TGF-β1, addition of exogenous bovine HAPLN1 (together with aggrecan G1) facilitated myofibroblast formation, as seen by significant upregulation of α-smooth muscle actin (SMA) staining, while adding full-length bovine versican had no effect. Increased compaction of hyaluronan-rich ECM suggests that HAPLN1 plus G1 addition affects hyaluronan networks and myofibroblast formation. These observations demonstrate changes in both extracellular and intracellular localization of HAPLN1 during fibroblast proliferation and myofibroblast conversion suggesting a possible role in fibrotic remodeling.

VUp-Regulation of VCAN Promotes the Proliferation, Invasion and Migration and Serves as a Biomarker in Gastric Cancer

Background

Versican (VCAN), a significant protein of extracellular matrix (ECM), is capable of accumulating in tumor stroma and critically impacts malignant transforming process and tumor progressing process. Promoted VCAN expression was identified in numerous malignant tumors and showed relationships to cancer relapse and ineffective breast, prostate, and many other cancer types of patients. Nevertheless, the molecular capability and prognosis importance exhibited by VCAN are infrequently presented in gastric cancer (GC).

Methods

According to 5 GC tissues and corresponding general tissues, mRNA expression profiles were taken here. VCAN expression in tissues was confirmed by quantitative reverse transcription polymerase reaction (qRT-PCR). The effect generated by VCAN expression on cell proliferating, invading and migrating processes was assessed in vitro with knockdown and overexpression strategies. Moreover, the relationships between immune response and VCAN expression in GC were assessed with the use of the software online.

Results

There are 181 genes up-regulated and 530 genes down-regulated in GC. According to pathway study, the mentioned differently expressed mRNAs showed correlations with a number of vital physiological processes, cellular components, molecular functions and critical cancer signal pathways. VCAN was reported to be noticeably promoted in GC tissues and related to individual cancer age, race, and stages. VCAN was up-regulated in 16 GC tissues compared to adjacent non-tumorous tissue specimens via qRT-PCR. GC patients exhibiting higher VCAN expression had less post-progression survival (PPS), first progression (FP) and overall survival (OS). Experimental processes in vitro revealed VCAN knockdown hindered, proliferated, invaded, and migrated levels of GC cells, whereas overexpression of VCAN played the opposite effect. Immune factors may interact with VCAN mRNA in GC, and VCAN was found noticeably linked with regulatory T cells (Tregs).

Conclusion

According to the mentioned results, VCAN critically impacts GC progression. Accordingly, VCAN is likely to be a potentially feasible prognosis marking element and a prominent cancer drug for GC patients.

Versican and Versican-matrikines in Cancer Progression, Inflammation, and Immunity

Versican is an extracellular matrix proteoglycan with key roles in multiple facets of cancer development, ranging from proliferative signaling, evasion of growth-suppressor pathways, regulation of cell death, promotion of neoangiogenesis, and tissue invasion and metastasis. Multiple lines of evidence implicate versican and its bioactive proteolytic fragments (matrikines) in the regulation of cancer inflammation and antitumor immune responses. The understanding of the dynamics of versican deposition/accumulation and its proteolytic turnover holds potential for the development of novel immune biomarkers as well as approaches to reset the immune thermostat of tumors, thus promoting efficacy of modern immunotherapies. This article summarizes work from several laboratories, including ours, on the role of this central matrix proteoglycan in tumor progression as well as tumor-immune cell cross-talk.

GORAB promotes embryonic lung maturation through antagonizing AKT phosphorylation, versican expression, and mesenchymal cell migration

Embryonic development of the alveolar sac of the lung is dependent upon multiple signaling pathways to coordinate cell growth, migration, and the formation of the extracellular matrix. Here, we identify GORAB as a regulator of embryonic alveolar sac formation as genetically disrupting the Gorab gene in mice resulted in fatal saccular maturation defects characterized by a thickened lung mesenchyme. This abnormality is not associated with impairments in cellular proliferation and death, but aberrantly increased protein kinase B (AKT) phosphorylation, elevated Vcan transcription, and enhanced migration of mesenchymal fibroblasts. Genetically augmenting PDGFRα, a potent activator of AKT in lung mesenchymal cells, recapitulated the alveolar phenotypes, whereas disrupting PDGFRα partially rescued alveolar phenotypes in Gorab-deficient mice. Overexpressing or suppressing Vcan in primary embryonic lung fibroblasts could, respectively, mimic or attenuate alveolar sac-like phenotypes in a co-culture model. These findings suggest a role of GORAB in negatively regulating AKT phosphorylation, the expression of Vcan, and the migration of lung mesenchyme fibroblasts, and suggest that alveolar sac formation resembles a patterning event that is orchestrated by molecular signaling and the extracellular matrix in the mesenchyme.

Respiratory Syncytial Virus Infection of Human Lung Fibroblasts Induces a Hyaluronan-Enriched Extracellular Matrix That Binds Mast Cells and Enhances Expression of Mast Cell Proteases

Human lung fibroblasts (HLFs) treated with the viral mimetic polyinosine-polycytidylic acid (poly I:C) form an extracellular matrix (ECM) enriched in hyaluronan (HA) that avidly binds monocytes and lymphocytes. Mast cells are important innate immune cells in both asthma and acute respiratory infections including respiratory syncytial virus (RSV); however, the effect of RSV on HA dependent mast cell adhesion and/or function is unknown. To determine if RSV infection of HLFs leads to the formation of a HA-enriched ECM that binds and enhances mast cell activity primary HLFs were infected with RSV for 48 h prior to leukocyte binding studies using a fluorescently labeled human mast cell line (LUVA). Parallel HLFs were harvested for characterization of HA production by ELISA and size exclusion chromatography. In separate experiments, HLFs were infected as above for 48 h prior to adding LUVA cells to HLF wells. Co-cultures were incubated for 48 h at which point media and cell pellets were collected for analysis. The role of the hyaladherin tumor necrosis factor-stimulated gene 6 (TSG-6) was also assessed using siRNA knockdown. RSV infection of primary HLFs for 48 h enhanced HA-dependent LUVA binding assessed by quantitative fluorescent microscopy. This coincided with increased HLF HA synthase (HAS) 2 and HAS3 expression and decreased hyaluronidase (HYAL) 2 expression leading to increased HA accumulation in the HLF cell layer and the presence of larger HA fragments. Separately, LUVAs co-cultured with RSV-infected HLFs for 48 h displayed enhanced production of the mast cell proteases, chymase, and tryptase. Pre-treatment with the HA inhibitor 4-methylumbelliferone (4-MU) and neutralizing antibodies to CD44 (HA receptor) decreased mast cell protease expression in co-cultured LUVAs implicating a direct role for HA. TSG-6 expression was increased over the 48-h infection. Inhibition of HLF TSG-6 expression by siRNA knockdown led to decreased LUVA binding suggesting an important role for this hyaladherin for LUVA adhesion in the setting of RSV infection. In summary, RSV infection of HLFs contributes to inflammation via HA-dependent mechanisms that enhance mast cell binding as well as mast cell protease expression via direct interactions with the ECM.

Versican in the Tumor Microenvironment

Versican is an extracellular matrix proteoglycan with nonredundant roles in diverse biological and cellular processes, ranging from embryonic development to adult inflammation and cancer. Versican is essential for cardiovascular morphogenesis, neural crest migration, and skeletal development during embryogenesis. In the adult, versican acts as an inflammation "amplifier" and regulator of immune cell activation and cytokine production. Increased versican expression has been observed in a wide range of malignant tumors and has been associated with poor patient outcomes. The main sources of versican production in the tumor microenvironment include accessory cells (myeloid cells and stromal components) and, in some contexts, the tumor cells themselves. Versican has been implicated in several classical hallmarks of cancer such as proliferative signaling, evasion of growth suppressor signaling, resistance to cell death, angiogenesis, and tissue invasion and metastasis. More recently, versican has been implicated in escape from tumor immune surveillance, e.g., through dendritic cell dysfunction. Versican's multiple contributions to benign and malignant biological processes are further diversified through the generation of versican-derived bioactive proteolytic fragments (matrikines), with versikine being the most studied to date. Versican and versican-derived matrikines hold promise as targets in the management of inflammatory and malignant conditions as well as in the development of novel predictive and prognostic biomarkers.

Metformin decreases hyaluronan synthesis by vascular smooth muscle cells

Metformin is the first-line drug in the treatment of type 2 diabetes worldwide based on its effectiveness and cardiovascular safety. Currently metformin is increasingly used during pregnancy in women with gestational diabetes mellitus, even if the long-term effects of metformin on offspring are not exactly known. We have previously shown that high glucose concentration increases hyaluronan (HA) production of cultured human vascular smooth muscle cells (VSMC) via stimulating the expression of hyaluronan synthase 2 (HAS2). This offers a potential mechanism whereby hyperglycemia leads to vascular macroangiopathy. In this study, we examined whether gestational metformin use affects HA content in the aortic wall of mouse offspring in vivo. We also examined the effect of metformin on HA synthesis by cultured human VSMCs in vitro. We found that gestational metformin use significantly decreased HA content in the intima-media of mouse offspring aortas. In accordance with this, the synthesis of HA by VSMCs was also significantly decreased in response to treatment with metformin. This decrease in HA synthesis was shown to be due to the reduction of both the expression of HAS2 and the amount of HAS substrates, particularly UDP-N-acetylglucosamine. As shown here, gestational metformin use is capable to program reduced HA content in the vascular wall of the offspring strongly supporting the idea, that metformin possesses long-term vasculoprotective effects.

Expression of Different Isoforms of Versican During the Development of Mouse Mandibular First Molars

Versican is a large chondroitin sulfate proteoglycan enriched in the extracellular matrix, and it has at least four different isoforms, termed V0, V1, V2, and V3. Although several studies have demonstrated that versican is stably expressed in various developing organs, the expression of versican isoforms during tooth development has not been elucidated yet. Therefore, the present study was to investigate the expression of versican isoforms in the developing mouse molars. The mandibular first molars from embryonic day (E) 11.5 to postnatal day (PN) 21 were used to investigate the expression of versican isoforms by immunohistochemistry, and the gene expressions of versican (Vcan) isoforms from E13.5 to PN7 were analyzed by quantitative real-time PCR. The results exhibited different expressing patterns of versican isoforms-the stellate reticulum (SR) and the dental mesenchymal cells adjacent to Hertwig's Epithelial Root Sheath (HERS) only expressed V1 and the mature odontoblasts mainly expressed V2, while the dental papilla and the ameloblasts might both express V0/V1/V2. These results suggested that different versican isoforms may act different roles in the tooth development, and we speculated that V0/V1 might be intimately involved in the cell proliferation while V2 was associated in the cytodifferentiation.

A role for proteoglycans in vascular disease

The content of proteoglycans (PGs) is low in the extracellular matrix (ECM) of vascular tissue, but increases dramatically in all phases of vascular disease. Early studies demonstrated that glycosaminoglycans (GAGs) including chondroitin sulfate (CS), dermatan sulfate (DS), keratan sulfate (KS) and heparan sulfate (HS) accumulate in vascular lesions in both humans and in animal models in areas of the vasculature that are susceptible to disease initiation (such as at branch points) and are frequently coincident with lipid deposits. Later studies showed the GAGs were covalently attached to specific types of core proteins that accumulate in vascular lesions. These molecules include versican (CSPG), biglycan and decorin (DS/CSPGs), lumican and fibromodulin (KSPGs) and perlecan (HSPG), although other types of PGs are present, but in lesser quantities. While the overall molecular design of these macromolecules is similar, there is tremendous structural diversity among the different PG families creating multiple forms that have selective roles in critical events that form the basis of vascular disease. PGs interact with a variety of different molecules involved in disease pathogenesis. For example, PGs bind and trap serum components that accumulate in vascular lesions such as lipoproteins, amyloid, calcium, and clotting factors. PGs interact with other ECM components and regulate, in part, ECM assembly and turnover. PGs interact with cells within the lesion and alter the phenotypes of both resident cells and cells that invade the lesion from the circulation. A number of therapeutic strategies have been developed to target specific PGs involved in key pathways that promote vascular disease. This review will provide a historical perspective of this field of research and then highlight some of the evidence that defines the involvement of PGs and their roles in the pathogenesis of vascular disease.

Hyaluronan negatively regulates vascular calcification involving BMP2 signaling

Vascular calcification is a highly regulated biological process similar to bone formation involving osteogenic differentiation of vascular smooth muscle cells (VSMCs). Hyaluronan (HA), a major structural component of the extracellular matrix in cartilage, has been shown to inhibit osteoblast differentiation. However, whether HA affects osteogenic differentiation and calcification of VSMCs remains unclear. In the present study, we used in vitro and ex vivo models of vascular calcification to investigate the role of HA in vascular calcification. Both high and low molecular weight HA treatment significantly reduced calcification of rat VSMCs in a dose-dependent manner, as detected by alizarin red staining and calcium content assay. Ex vivo study further confirmed the inhibitory effect of HA on vascular calcification. Similarly, HA treatment decreased ALP activity and expression of bone-related molecules including Runx2, BMP2 and Msx2. By contrast, inhibition of HA synthesis by 4-methylumbelliferone (4MU) promoted calcification of rat VSMCs. In addition, adenovirus-mediated overexpression of HA synthase 2 (HAS2), a major HA synthase in VSMCs, also inhibited calcification of VSMCs, whereas CRISPR/Cas9-mediated HAS2 knockout promoted calcification of rat A10 cells. Furthermore, we found that BMP2 signaling was inhibited in VSMCs after HA treatment. Recombinant BMP2 enhanced high calcium and phosphate-induced VSMC calcification, which can be blocked by HA treatment. Taken together, these findings suggest that HA inhibits vascular calcification involving BMP2 signaling.

Versican is differentially regulated in the adventitial and medial layers of human vein grafts

Changes in extracellular matrix proteins may contribute significantly to the adaptation of vein grafts to the arterial circulation. We examined the production and distribution of versican and hyaluronan in intact human vein rings cultured ex vivo, veins perfused ex vivo, and cultured venous adventitial and smooth muscle cells. Immunohistochemistry revealed higher levels of versican in the intima/media compared to the adventitia, and no differences in hyaluronan. In the vasa vasorum, versican and hyaluronan associated with CD34⁺ progenitor cells. Culturing the vein rings for 14 days revealed increased versican immunostaining of 30–40% in all layers, with no changes in hyaluronan. Changes in versican accumulation appear to result from increased synthesis in the intima/media and decreased degradation in the adventitia as versican transcripts were increased in the intima/media, but unchanged in the adventitia, and versikine (the ADAMTS-mediated cleavage product of versican) was increased in the intima/media, but decreased in the adventitia. In perfused human veins, versican was specifically increased in the intima/media in the presence of venous pressure, but not with arterial pressure. Unexpectedly, cultured adventitial cells express and accumulate more versican and hyaluronan than smooth muscle cells. These data demonstrate a differential regulation of versican and hyaluronan in human venous adventitia vs. intima/media and suggest distinct functions for these extracellular matrix macromolecules in these venous wall compartments during the adaptive response of vein grafts to the arterial circulation.

Glucocorticoids influence versican and chondroitin sulphate proteoglycan levels in the fetal sheep lung

BACKGROUND

Prenatal glucocorticoid treatment decreases alveolar tissue volumes and facilitates fetal lung maturation, however the mechanisms responsible are largely unknown. This study examines whether changes in versican levels or sulphation patterns of chondroitin sulphate (CS) side chains, are associated with glucocorticoid-induced reductions in peri-alveolar tissue volumes.

METHODS

Lung tissue was collected from 1) fetal sheep at 131 ± 0.1 days gestational age (GA) infused with cortisol (122-131d GA) to prematurely induce a pre-parturient-like rise in circulating cortisol, 2) fetal sheep at 143d GA bilaterally adrenalectomised (ADX) at 112d GA to remove endogenous cortisol and 3) fetal sheep at 124d GA in which bolus doses (2 × 11.4 mg) of betamethasone were administered to the pregnant ewe. The level and distribution of versican and CS glycosaminoglycans (GAG) were determined using immunohistochemistry (IHC). Fluorophore assisted carbohydrate electrophoresis (FACE) was used to determine changes in CS sulphation patterns.

RESULTS

Cortisol infusion significantly decreased chondrotin-6-sulphate levels (C-6-S) to 16.4 ± 0.7 AU, compared with saline-infused fetuses (18.9 ± 0.7 AU: p = 0.04) but did not significantly alter the level of versican or chondroitin-4-sulphate (C-4-S). ADX significantly increased the level of C-4-S (28.2 ± 2.2 AU), compared with sham-operated fetuses (17.8 ± 2.0 AU; p = 0.006) without altering versican or C-6-S levels. Betamethasone significantly decreased versican, C-4-S and C-6-S in the fetal sheep lung (19.2 ± 0.9 AU, 24.9 ± 1.4 AU and 23.2 ± 1.0 AU, respectively), compared with saline-exposed fetuses (24.3 ± 0.4 AU, p = 0.0004; 33.3±0.6 AU, p = 0.0003; 29.8±1.3 AU, 0.03, respectively).

CONCLUSIONS

These results indicate that glucocorticoids alter versican levels and CS side chain microstructure in alveolar lung tissue. Betamethasone appears to have a greater impact on versican and CS side chains than cortisol.

Transcription and microRNA Profiling of Cultured Human Tympanic Membrane Epidermal Keratinocytes

The human tympanic membrane (TM) has a thin outer epidermal layer which plays an important role in TM homeostasis and ear health. The specialised cells of the TM epidermis have a different physiology compared to normal skin epidermal keratinocytes, displaying a dynamic and constitutive migration that maintains a clear TM surface and assists in regeneration. Here, we characterise and compare molecular phenotypes in keratinocyte cultures from TM and normal skin. TM keratinocytes were isolated by enzymatic digestion and cultured in vitro. We compared global mRNA and microRNA expression of the cultured cells with that of human epidermal keratinocyte cultures. Genes with either relatively higher or lower expression were analysed further using the biostatistical tools g:Profiler and Ingenuity Pathway Analysis. Approximately 500 genes were found differentially expressed. Gene ontology enrichment and Ingenuity analyses identified cellular migration and closely related biological processes to be the most significant functions of the genes highly expressed in the TM keratinocytes. The genes of low expression showed a marked difference in homeobox (HOX) genes of clusters A and C, giving the TM keratinocytes a strikingly low HOX gene expression profile. An in vitro scratch wound assay showed a more individualised cell movement in cells from the tympanic membrane than normal epidermal keratinocytes. We identified 10 microRNAs with differential expression, several of which can also be linked to regulation of cell migration and expression of HOX genes. Our data provides clues to understanding the specific physiological properties of TM keratinocytes, including candidate genes for constitutive migration, and may thus help focus further research.

Massive aggrecan and versican accumulation in thoracic aortic aneurysm and dissection

Proteoglycan accumulation is a hallmark of medial degeneration in thoracic aortic aneurysm and dissection (TAAD). Here, we defined the aortic proteoglycanome using mass spectrometry, and based on the findings, investigated the large aggregating proteoglycans aggrecan and versican in human ascending TAAD and a mouse model of severe Marfan syndrome. The aortic proteoglycanome comprises 20 proteoglycans including aggrecan and versican. Antibodies against these proteoglycans intensely stained medial degeneration lesions in TAAD, contrasting with modest intralamellar staining in controls. Aggrecan, but not versican, was increased in longitudinal analysis of Fbn1mgR/mgR aortas. TAAD and Fbn1mgR/mgR aortas had increased aggrecan and versican mRNAs, and reduced expression of a key proteoglycanase gene, ADAMTS5, was seen in TAAD. Fbn1mgR/mgR mice with ascending aortic dissection and/or rupture had dramatically increased aggrecan staining compared with mice without these complications. Thus, aggrecan and versican accumulation in ascending TAAD occurs via increased synthesis and/or reduced proteolytic turnover, and correlates with aortic dissection/rupture in Fbn1mgR/mgR mice. Tissue swelling imposed by aggrecan and versican is proposed to be profoundly deleterious to aortic wall mechanics and smooth muscle cell homeostasis, predisposing to type-A dissections. These proteoglycans provide potential biomarkers for refined risk stratification and timing of elective aortic aneurysm repair.

Role of hyaluronan in atherosclerosis: Current knowledge and open questions

Hyaluronan (HA), HA synthases (HAS) and HA receptors are expressed during the progression of atherosclerotic plaques. HA is thought to promote the activated phenotype of local vascular smooth muscle cells characterized by increased migration, proliferation and matrix synthesis. Furthermore, HA may modulate the immune response by increasing macrophage retention and by promoting the polarization of Th1 cells that enhance macrophage driven inflammation as well. The pro-atherosclerotic functions of HA are opposed by the presence of HA in the glycocalyx where it critically contributes to anti-thrombotic and anti-inflammatory function of the glycocalyx. Patients with atherosclerosis often are affected by comorbidities among them diabetes mellitus type 2 and inflammatory comorbidities. Diabetes mellitus type 2 likely has close interrelations to HA synthesis in atherosclerosis because the activity and transcription of HA synthases are sensitive to the intracellular glucose metabolism, which determines the substrate availability and the posttranslational modifications of HA synthases. The pro-inflammatory comorbidities aggravate the course of atherosclerosis and will affect the expression of the genes related to HA biosynthesis, -degradation, HA-matrix assembly or signaling. One example being the induction of HAS3 by interleukin-1β and other cytokines. Furthermore complications of atherosclerosis such as the healing after myocardial infarction also involve HA responses.

Regulation of hyaluronan biosynthesis and clinical impact of excessive hyaluronan production

The tightly regulated biosynthesis and catabolism of the glycosaminoglycan hyaluronan, as well as its role in organizing tissues and cell signaling, is crucial for the homeostasis of tissues. Overexpression of hyaluronan plays pivotal roles in inflammation and cancer, and markedly high serum and tissue levels of hyaluronan are noted under such pathological conditions. This review focuses on the complexity of the regulation at transcriptional and posttranslational level of hyaluronan synthetic enzymes, and the outcome of their aberrant expression and accumulation of hyaluronan in clinical conditions, such as systemic B-cell cancers, aggressive breast carcinomas, metabolic diseases and virus infection.

Microsomal Prostaglandin E Synthase-1 Expression by Aortic Smooth Muscle Cells Attenuates the Differentiated Phenotype

The development of numerous types of cardiovascular disease is associated with alteration of the vascular smooth muscle cell (SMC) phenotype. We have previously shown that abdominal aortic aneurysm progression in a mouse model of the disease is associated with reduced differentiation of SMCs within the lesion and that cyclooxygenase-2 (COX-2) is critical to initiation and progression of the aneurysms. The current studies used human aortic SMC (hASMC) cultures to better characterize mechanisms responsible for COX-2-dependent modulation of the SMC phenotype. Depending on the culture conditions, hASMCs expressed multiple characteristics of a differentiated and contractile phenotype, or a dedifferentiated and secretory phenotype. The pharmacological inhibition of COX-2 promoted the differentiated phenotype, whereas treatment with the COX-2-derived metabolite prostaglandin E2 (PGE2) increased characteristics of the dedifferentiated phenotype. Furthermore, pharmacological inhibition or siRNA-mediated knockdown of microsomal prostaglandin E synthase-1 (mPGES-1), the enzyme that functions downstream of COX-2 during the synthesis of PGE2, significantly increased expression of characteristics of the differentiated SMC phenotype. Therefore, our findings suggest that COX-2 and mPGES-1-dependent synthesis of PGE2 contributes to a dedifferentiated hASMC phenotype and that mPGES-1 may provide a novel pharmacological target for treatment of cardiovascular diseases where altered SMC differentiation has a causative role.

Cell Surface Access Is Modulated by Tethered Bottlebrush Proteoglycans

The hyaluronan-rich pericellular matrix (PCM) plays physical and chemical roles in biological processes ranging from brain plasticity, to adhesion-dependent phenomena such as cell migration, to the onset of cancer. This study investigates how the spatial distribution of the large negatively charged bottlebrush proteoglycan, aggrecan, impacts PCM morphology and cell surface access. The highly localized pericellular milieu limits transport of nanoparticles in a size-dependent fashion and sequesters positively charged molecules on the highly sulfated side chains of aggrecan. Both rat chondrocyte and human mesenchymal stem cell PCMs possess many unused binding sites for aggrecan, showing a 2.5x increase in PCM thickness from ∼7 to ∼18 μm when provided exogenous aggrecan. Yet, full extension of the PCM occurs well below aggrecan saturation. Hence, cells equipped with hyaluronan-rich PCM can in principle manipulate surface accessibility or sequestration of molecules by tuning the bottlebrush proteoglycan content to alter PCM porosity and the number of electrostatic binding sites.

Versican Proteolysis by ADAMTS Proteases and Its Influence on Sex Steroid Receptor Expression in Uterine Leiomyoma

CONTEXT

Leiomyomas have abundant extracellular matrix (ECM), with upregulation of versican, a large proteoglycan.

OBJECTIVE

We investigated ADAMTS (a disintegrin-like and metalloprotease with thrombospondin type 1 motifs) protease-mediated versican cleavage in myometrium and leiomyoma and the effect of versican knockdown in leiomyoma cells.

DESIGN

We used quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blotting, immunohistochemistry, and RNA in situ hybridization for analysis of myometrium, leiomyoma and immortalized myometrium and leiomyoma cells. Short interfering RNA (siRNA) was used to knockdown versican in leiomyoma cells.

SETTING

This study was performed in an academic laboratory.

PATIENTS

Study subjects were women with symptomatic or asymptomatic leiomyoma.

MAIN OUTCOME MEASURES

We quantified messenger RNAs (mRNAs) for versican splice variants. We identified ADAMTS-cleaved versican in myometrium and leiomyoma and ADAMTS messenger RNAs and examined the effect of VCAN siRNA on smooth muscle differentiation and expression of estrogen and progesterone receptors.

RESULTS

The women in the symptomatic group (n = 7) had larger leiomyoma (P = 0.01), heavy menstrual bleeding (P < 0.01), and lower hemoglobin levels (P = 0.02) compared with the asymptomatic group (n = 7), but were similar in age and menopausal status. Versican V0 and V1 isoforms were upregulated in the leiomyomas of symptomatic versus asymptomatic women (P = 0.03 and P = 0.04, respectively). Abundant cleaved versican was detected in leiomyoma and myometrium, as well as in myometrial and leiomyoma cell lines. ADAMTS4 (P = 0.03) and ADAMTS15 (P = 0.04) were upregulated in symptomatic leiomyomas. VCAN siRNA did not effect cell proliferation, apoptosis, or smooth muscle markers, but reduced ESR1 and PR-A expression (P = 0.001 and P = 0.002, respectively).

CONCLUSIONS

Versican in myometrium, leiomyomas and in the corresponding immortalized cells is cleaved by ADAMTS proteases. VCAN siRNA suppresses production of estrogen receptor 1 and progesterone receptor-A. These findings have implications for leiomyoma growth.

Provisional matrix: A role for versican and hyaluronan

Hyaluronan and versican are extracellular matrix (ECM) components that are enriched in the provisional matrices that form during the early stages of development and disease. These two molecules interact to create pericellular "coats" and "open space" that facilitate cell sorting, proliferation, migration, and survival. Such complexes also impact the recruitment of leukocytes during development and in the early stages of disease. Once thought to be inert components of the ECM that help hold cells together, it is now quite clear that they play important roles in controlling cell phenotype, shaping tissue response to injury and maintaining tissue homeostasis. Conversion of hyaluronan-/versican-enriched provisional matrix to collagen-rich matrix is a "hallmark" of tissue fibrosis. Targeting the hyaluronan and versican content of provisional matrices in a variety of diseases including, cardiovascular disease and cancer, is becoming an attractive strategy for intervention.

Kinetics of versican-expressing macrophages in bone marrow after cord blood stem cell transplantation for treatment of acute myelogenous leukaemia

Aims

To determine versican-producing cells in normocellular bone marrow and to evaluate chronological alteration in the number of versican-producing macrophages in bone marrow of patients with acute myelogenous leukaemia (AML) after cord blood stem cell transplantation (CBSCT) to gain insight in the significance of versican in recovery of haematopoiesis.

Methods

We enrolled seven age-matched unrelated patients with normocellular bone marrow for determining versican-producing cells in bone marrow, CBSCT-treated patients with AML, 18 with fine and other four with poor engraftment, for determining chronological alteration of versican-expressing and CD68-expressing cells in transplanted bone marrow in reference to the total cells. Clot samples of patients with AML were collected from the +16 to +55 day after transplantation and separated into four groups. We included an AML case whose specimen was obtained on the +9 day. Cells positive in immunohistochemistry using antibodies to versican and CD68 were counted to obtain the mean±SD in a unit area of the bone marrow, plotted chronologically and compared with the numbers from the age-matched normocellular group.

Results

We determined by a double immunohistochemistry that the versican-expressing cells in bone marrow are macrophages. The time-course curve demonstrated an inverse relationship between the versican-positive macrophages and the total cells in the transplanted bone marrow for over 55 days. In bone marrow of poor engraftment cases, versican-positive macrophages appeared to be decreased in comparison with age-matched and sampling day-matched patients.

Conclusions

These results suggest that versican and/or versican-expressing macrophages positively contribute to bone marrow regeneration of patients with AML after CBSCT.

Cellular and Molecular Mechanisms of Phenotypic Switch in Gastrointestinal Smooth Muscle

As a general rule, smooth muscle cells (SMC) are able to switch from a contractile phenotype to a less mature synthetic phenotype. This switch is accompanied by a loss of differentiation with decreased expression of contractile markers, increased proliferation as well as the synthesis and the release of several signaling molecules such as pro-inflammatory cytokines, chemotaxis-associated molecules, and growth factors. This SMC phenotypic plasticity has extensively been investigated in vascular diseases, but interest is also emerging in the field of gastroenterology. It has in fact been postulated that altered microenvironmental conditions, including the composition of microbiota, could trigger the remodeling of the enteric SMC, with phenotype changes and consequent alterations of contraction and impairment of gut motility. Several molecular actors participate in this phenotype remodeling. These include extracellular molecules such as cytokines and extracellular matrix proteins, as well as intracellular proteins, for example, transcription factors. Epigenetic control mechanisms and miRNA have also been suggested to participate. In this review key roles and actors of smooth muscle phenotypic switch, mainly in GI tissue, are described and discussed in the light of literature data available so far. J. Cell. Physiol. 231: 295-302, 2016. © 2015 Wiley Periodicals, Inc.

Versican V1 Overexpression Induces a Myofibroblast-Like Phenotype in Cultured Fibroblasts

Background

Versican, a chondroitin sulphate proteoglycan, is one of the key components of the provisional extracellular matrix expressed after injury. The current study evaluated the hypothesis that a versican-rich matrix alters the phenotype of cultured fibroblasts.

Methods and Results

The full-length cDNA for the V1 isoform of human versican was cloned and the recombinant proteoglycan was expressed in murine fibroblasts. Versican expression induced a marked change in fibroblast phenotype. Functionally, the versican-expressing fibroblasts proliferated faster and displayed enhanced cell adhesion, but migrated slower than control cells. These changes in cell function were associated with greater N-cadherin and integrin β1 expression, along with increased FAK phosphorylation. The versican-expressing fibroblasts also displayed expression of smooth muscle α-actin, a marker of myofibroblast differentiation. Consistent with this observation, the versican fibroblasts displayed increased synthetic activity, as measured by collagen III mRNA expression, as well as a greater capacity to contract a collagen lattice. These changes appear to be mediated, at least in part, by an increase in active TGF-β signaling in the versican expressing fibroblasts, and this was measured by phosphorylation and nuclear accumulation of SMAD2.

Conclusions

Collectively, these data indicate versican expression induces a myofibroblast-like phenotype in cultured fibroblasts.

Expression of V3 Versican by Rat Arterial Smooth Muscle Cells Promotes Differentiated and Anti-inflammatory Phenotypes

Arterial smooth muscle cells (ASMCs) undergo phenotypic changes during development and pathological processes in vivo and during cell culture in vitro. Our previous studies demonstrated that retrovirally mediated expression of the versican V3 splice variant (V3) by ASMCs retards cell proliferation and migration in vitro and reduces neointimal thickening and macrophage and lipid accumulation in animal models of vascular injury and atherosclerosis. However, the molecular pathways induced by V3 expression that are responsible for these changes are not yet clear. In this study, we employed a microarray approach to examine how expression of V3 induced changes in gene expression and the molecular pathways in rat ASMCs. We found that forced expression of V3 by ASMCs affected expression of 521 genes by more than 1.5-fold. Gene ontology analysis showed that components of the extracellular matrix were the most significantly affected by V3 expression. In addition, genes regulating the formation of the cytoskeleton, which also serve as markers of contractile smooth muscle cells (SMCs), were significantly up-regulated. In contrast, components of the complement system, chemokines, chemokine receptors, and transcription factors crucial for regulating inflammatory processes were among the genes most down-regulated. Consistently, we found that the level of myocardin, a key transcription factor promoting contractile SMC phenotype, was greatly increased, and the proinflammatory transcription factors NFκB1 and CCAAT/enhancer-binding protein β were significantly attenuated in V3-expressing SMCs. Overall, these findings demonstrate that V3 expression reprograms ASMCs promoting differentiated and anti-inflammatory phenotypes.

Computational modelling suggests good, bad and ugly roles of glycosaminoglycans in arterial wall mechanics and mechanobiology

The medial layer of large arteries contains aggregates of the glycosaminoglycan hyaluronan and the proteoglycan versican. It is increasingly thought that these aggregates play important mechanical and mechanobiological roles despite constituting only a small fraction of the normal arterial wall. In this paper, we offer a new hypothesis that normal aggregates of hyaluronan and versican pressurize the intralamellar spaces, and thereby put into tension the radial elastic fibres that connect the smooth muscle cells to the elastic laminae, which would facilitate mechanosensing. This hypothesis is supported by novel computational simulations using two complementary models, a mechanistically based finite-element mixture model and a phenomenologically motivated continuum hyperelastic model. That is, the simulations suggest that normal aggregates of glycosaminoglycans/proteoglycans within the arterial media may play equally important roles in supporting (i.e. a structural role) and sensing (i.e. an instructional role) mechanical loads. Additional simulations suggest further, however, that abnormal increases in these aggregates, either distributed or localized, may over-pressurize the intralamellar units. We submit that these situations could lead to compromised mechanosensing, anoikis and/or reduced structural integrity, each of which represent fundamental aspects of arterial pathologies seen, for example, in hypertension, ageing and thoracic aortic aneurysms and dissections.

A role for versican in the development of leiomyosarcoma

Leiomyosarcoma (LMS) is a mesenchymal cancer that occurs throughout the body. Although LMS is easily recognized histopathologically, the cause of the disease remains unknown. Versican, an extracellular matrix proteoglycan, increases in LMS. Microarray analyses of 80 LMSs and 24 leiomyomas showed a significant elevated expression of versican in human LMS versus benign leiomyomas. To explore the importance of versican in this smooth muscle cell tumor, we used versican-directed siRNA to knock down versican expression in a LMS human cell line, SK-LMS-1. Decreased versican expression was accompanied by slower rates of LMS cell proliferation and migration, increased adhesion, and decreased accumulation of the extracellular matrix macromolecule hyaluronan. Addition of purified versican to cells expressing versican siRNA restored cell proliferation to the level of LMS controls, increased the pericellular coat and the retention of hyaluronan, and decreased cell adhesion in a dose-dependent manner. The presence of versican was not only synergistic with hyaluronan in increasing cell proliferation, but the depletion of versican decreased hyaluronan synthase expression and decreased the retention of hyaluronan. When LMS cells stably expressing versican siRNA were injected into nude mice, the resulting tumors displayed significantly less versican and hyaluronan staining, had lower volumes, and had reduced levels of mitosis as compared with controls. Collectively, these results suggest a role for using versican as a point of control in the management and treatment of LMS.

Hapln1a is required for connexin43-dependent growth and patterning in the regenerating fin skeleton

Cell–cell communication, facilitating the exchange of small metabolites, ions and second messengers, takes place via aqueous proteinaceous channels called gap junctions. Connexins (cx) are the subunits of a gap junction channel. Mutations in zebrafish cx43 produces the short fin (sof ^b123) phenotype and is characterized by short fins due to reduced segment length of the bony fin rays and reduced cell proliferation. Previously established results from our lab demonstrate that Cx43 plays a dual role regulating both cell proliferation (growth) and joint formation (patterning) during the process of skeletal morphogenesis. In this study, we show that Hapln1a (Hyaluronan and Proteoglycan Link Protein 1a) functions downstream of cx43. Hapln1a belongs to the family of link proteins that play an important role in stabilizing the ECM by linking the aggregates of hyaluronan and proteoglycans. We validated that hapln1a is expressed downstream of cx43 by in situ hybridization and quantitative RT-PCR methods. Moreover, in situ hybridization at different time points revealed that hapln1a expression peaks at 3 days post amputation. Expression of hapln1a is located in the medial mesenchyme and the in the lateral skeletal precursor cells. Furthermore, morpholino mediated knock-down of hapln1a resulted in reduced fin regenerate length, reduced bony segment length and reduced cell proliferation, recapitulating all the phenotypes of cx43 knock-down. Moreover, Hyaluronic Acid (HA) levels are dramatically reduced in hapln1a knock-down fins, attesting the importance of Hapln1a in stabilizing the ECM. Attempts to place hapln1a in our previously defined cx43–sema3d pathway suggest that hapln1a functions in a parallel genetic pathway. Collectively, our data suggest that Cx43 mediates independent Sema3d and Hapln1a pathways in order to coordinate skeletal growth and patterning.

Versican and the control of inflammation

Versican is an extracellular matrix (ECM) proteoglycan that interacts with cells by binding to non-integrin and integrin receptors and to other ECM components that associate with the cell surface. Recent studies have shown also that versican interacts with myeloid and lymphoid cells promoting their adhesion and production of inflammatory cytokines. Versican is produced by stromal cells, as well as leukocytes, and is markedly increased in inflammation. Inflammatory agonists, such as double-stranded RNA mimetics (e.g., poly I:C), stimulate stromal cells, smooth muscle cells and fibroblasts, to produce fibrillar ECMs enriched in versican and hyaluronan (HA) that interact with leukocytes promoting their adhesion. Interference with the incorporation of versican into this ECM blocks monocyte adhesion and dampens the inflammatory response. Tumor cells also express elevated levels of versican which interact with myeloid cells to promote an inflammatory response, through stimulating cytokine release, and metastasis. In addition, myeloid cells, such as macrophages in tumors, synthesize versican which affects tumor cell phenotypes, inflammation, and subsequent metastasis. Versican, by binding to hyaluronan, influences T lymphocyte phenotypes and in part controls the ability of these cells to synthesize and secrete cytokines that influence the immune response. Collectively, these studies indicate that versican as an ECM molecule plays a central role in inflammation and as a result it is emerging as a potential target promising wide therapeutic benefits.

Interfacial biology of in-stent restenosis

Percutaneous angioplasty is a nonsurgical method able to restore patency in atherosclerotic blood vessels through the expansion of a balloon. The clinical outcome of this technique has been significantly enhanced by the combined deployment of a stent. Although stents are successful in the majority of cases, a large percentage of patients (20-30%) still suffer a second vessel lumen reduction known as in-stent restenosis. In-stent restenosis is recognized to be caused by the mechanical and foreign body challenges elicited by the device. Drug-eluting stents have been recently made available to tackle restenosis, but their short clinical history and high costs may limit their future use. The present review links the most recent biologic findings related to in-stent restenosis to the devices' phyisico-chemical features in an attempt to demonstrate that a new generation of stents may be developed without the need of drug elution.

Versican and the regulation of cell phenotype in disease

BACKGROUND

Versican is an extracellular matrix (ECM) proteoglycan that is present in the pericellular environment of most tissues and increases in many different diseases. Versican interacts with cells to influence the ability of cells to proliferate, migrate, adhere and assemble an ECM.

SCOPE OF REVIEW

The structure of the versican molecule is briefly reviewed and studies highlighting those factors that promote versican synthesis and degradation and their impact on cell phenotype in disease are discussed. Particular attention is given to vascular disease, but other diseases where versican is important are covered as well, most notably different forms of cancers. Attention is given to mechanisms(s) by which versican influences cell behaviors through either direct or indirect processes. Versican produced by either stromal cells or myeloid cells can have a major impact influencing immunity and inflammation. Finally, studies controlling versican accumulation that either delay or inhibit the progression of disease will be highlighted.

MAJOR CONCLUSIONS

Versican is one component of the ECM that can influence the ability of cells to proliferate, migrate, adhere, and remodel the ECM. Targeting versican as a way to control cell phenotype offers a novel approach in the treatment of disease.

SIGNIFICANCE

ECM molecules such as versican contribute to the structural integrity of tissues and interact with cells through direct and indirect means to regulate, in part, cellular events that form the basis of disease. This article is part of a Special Issue entitled Matrix-mediated cell behaviour and properties.

HAS2 and CD44 in breast tumorigenesis

Metastatic spread of breast cancer cells, facilitated by the epithelial-mesenchymal transition (EMT) process, is responsible for the majority of breast cancer mortality. Increased levels of hyaluronan due to deregulation of hyaluronan-synthesizing enzymes, like HAS2, and expression of CD44, the key receptor for hyaluronan, are correlated to poor outcome of patients with basal-like breast cancer. TGFβ induces HAS2 and CD44, both of which are required in the course of efficient TGFβ-induced EMT processes by mammary epithelial cells. Elucidation of the molecular mechanisms underlying tumor-stroma interactions in breast cancer including the regulation of HAS2 and CD44 expression may contribute to the development of better strategies to treat breast cancer patients.

Thrombospondin-1-induced smooth muscle cell chemotaxis and proliferation are dependent on transforming growth factor-β2 and hyaluronic acid synthase

Angioplasty causes local vascular injury, leading to the release of thrombospondin-1 (TSP-1), which stimulates vascular smooth muscle cell (VSMC) migration and proliferation, important steps in the development of intimal hyperplasia. Transforming growth factor beta 2 (TGF-β2) and hyaluronic acid synthase (HAS) are two pro-stenotic genes upregulated in VSMCs by TSP-1. We hypothesized that inhibition of TGF-β2 or HAS would inhibit TSP-1-induced VSMC migration, proliferation, and TSP-1 signaling. Our data demonstrate that Inhibition of either TGF-β2 or HAS inhibited TSP-1-induced VSMC migration and proliferation. Activation of ERK 1 was decreased by TGF-β2 inhibition and unaffected by HAS inhibition. TGF-β2 and HAS are not implicated in TSP-1-induced thbs1 expression, while they are each implicated in TSP-1-induced expression of their own gene. In summary, TSP-1-induced VSMC migration and proliferation rely on intact TGF-β2 signaling and HAS function. TSP-1 activation of ERK 1 is dependent on TGF-β2. These data further expand our understanding of the complexity of TSP-1 cellular signaling and the involvement of TGF-β2 and HAS.

Effectiveness of cyclooxygenase-2 inhibition in limiting abdominal aortic aneurysm progression in mice correlates with a differentiated smooth muscle cell phenotype

Abdominal aortic aneurysms (AAAs) are a chronic condition that often progress over years to produce a weakened aorta with increased susceptibility for rupture, and currently, there are no pharmacological treatments available to slow disease progression. AAA development has been characterized by increased expression of cyclooxygenase-2 (COX-2), and inactivation of COX-2 before disease initiation reduces AAA incidence in a mouse model of the disease. The current study determined the effectiveness of COX-2 inhibition on AAA progression when treatment was begun after initiation of the disease. COX-2 inhibitor treatment with celecoxib was initiated after angiotensin II-induced AAA formation in a strain of nonhyperlipidemic mice that we have previously identified as highly susceptible to AAA development. When analyzed at different time points during progression of the disease, celecoxib treatment significantly reduced the incidence and severity of AAAs. The celecoxib treatment also protected the mice from aortic rupture and death. The aneurysmal lesion displayed an altered smooth muscle cell (SMC) phenotype, whereas celecoxib treatment was associated with increased expression of differentiated SMC markers and reduced dedifferentiation marker expression during AAA progression. Maintenance of a differentiated SMC phenotype is associated with the effectiveness of COX-2 inhibition for limiting AAA progression in nonhyperlipidemic mice.

Cyclooxygenase-2 inhibition attenuates abdominal aortic aneurysm progression in hyperlipidemic mice

Abdominal aortic aneurysms (AAAs) are a chronic inflammatory disease that increase the risk of life-threatening aortic rupture. In humans, AAAs have been characterized by increased expression of cyclooxygenase-2 and the inactivation of COX-2 prior to disease initiation reduces AAA incidence in a mouse model of the disease. The current study examined the effectiveness of selective cyclooxygenase-2 (COX-2) inhibition on reducing AAA progression when administered after the initiation of AAA formation. AAAs were induced in hyperlipidemic apolipoprotein E-deficient mice by chronic angiotensin II (AngII) infusion and the effect of treatment with the COX-2 inhibitor celecoxib was examined when initiated at different stages of the disease. Celecoxib treatment that was started 1 week after initiating AngII infusion reduced AAA incidence by 61% and significantly decreased AAA severity. Mice treated with celecoxib also showed significantly reduced aortic rupture and mortality. Treatment with celecoxib that was started at a late stage of AAA development also significantly reduced AAA incidence and severity. Celecoxib treatment significantly increased smooth muscle alpha-actin expression in the abdominal aorta and did not reduce expression of markers of macrophage-dependent inflammation. These findings indicate that COX-2 inhibitor treatment initiated after formation of AngII-induced AAAs effectively reduces progression of the disease in hyperlipidemic mice.