Small Proteoglycans Decorin Research Articles

Abstract C030: Serum levels and tumor tissue organization of decorin in pancreatic cancer: Links to chemoresistance and disease aggressiveness

Abstract Pancreatic cancer has nearly paralleling incidence and mortality rates. Only 15-20% of the tumors are resectable at presentation, and for the majority of patients the situation is palliative. Treatment options are limited to standard chemotherapy, and tumor response is often transient. The longitudinal observational clinical study Chemotherapy, Host response And Molecular dynamics in Periampullary cancer (CHAMP) aims to contribute with new insights on this devastating disease through longitudinal blood sampling during adjuvant and palliative chemotherapy and comprehensive analysis of tissue from resected as well as postmortem sampled tumor tissue. In the present study, encompassing the first 100 patients enrolled in the CHAMP study, 92 serum proteins related to inflammation and cancer were analyzed by proximity extension assay in on-treatment blood samples from baseline to six months. The results revealed that the small leucin-rich proteoglycan decorin was among the top up-regulated proteins during chemotherapy. After three months of treatment, high levels of serum decorin were significantly associated with a shorter overall survival (log rank p = 0.005). Decorin expression was also assessed by immunohistochemistry in resected tumors from 25 patients and in postmortem sampled primary tumors and metastases from 9 patients. In the latter, particularly strong expression of decorin, both in the tumor cells and in the stroma, was denoted in cases with a short overall survival. While there was no significant correlation between decorin in the tumors and in serum at baseline, strong correlations were seen at one and three months (Spearman’s rho = 0.70 and 0.85, respectively). To further validate the potential prognostic value of decorin, immunohistochemical analysis was performed on tumors from a retrospective cohort of 104 resected tumors with long-term follow-up. Survival analysis showed that high decorin expression in both the stromal compartment and in tumor cells was associated with shorter overall survival (log rank p = 0.036 and 0.001, respectively). Multivariable cox regression analysis, adjusted for conventional prognostic factors, further confirmed that decorin was an independent factor of shorter overall survival (hazard ratio: 1.74, 95% confidence interval 1.10-2.75 for stromal decorin, and hazard ratio: 1.83, 95% confidence interval 1.04-3.21 for tumor-cell specific decorin). In conclusion, these findings suggest that decorin may be associated with chemotherapy resistance in pancreatic cancer. Future studies are encouraged to further explore the mechanistic basis for these observations, and to validate the potential utility of serum-decorin as a biomarker to monitor treatment response. Citation Format: Maja Svensson, Johan Ohlsson, Sofie Olsson Hau, Alexandra Petersson, Karin Jirström. Serum levels and tumor tissue organization of decorin in pancreatic cancer: Links to chemoresistance and disease aggressiveness [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr C030.

Abstract 12006: Smooth Muscle Cell Embryologic Origin Does Not Define Propensity for Phenotype Modulation in Murine Marfan Syndrome Aortic Root Aneurysm

Introduction: Vascular smooth muscle cells (SMC) undergo phenotype modulation (silenced contractile genes and activated proteolytic/synthetic genes) in Marfan syndrome (MFS) aortic aneurysm. Aortic root SMCs develop from the second heart field (SHF) proximally and neural crest (NC) distally. We hypothesize that both developmental lineage and hemodynamic factors dictate SMC vulnerability to phenotype change, promoting focal aortic root aneurysm. Methods/Results: Aortic roots from adult MFS and littermate control mice (n=4 each sex) with a knockin fluorescent SHF tracing construct ( Nkx2-5 cre ) were sorted for lineage-resolved single cell RNA sequencing (scRNAseq). Modulated SMCs (modSMC) were enriched in MFS vs. controls (18.1% of all SMCs vs. 2.2%) and originated from both SHF (15.5%) and NC (20.2%) lineages, ruling out complete lineage specificity. NC-derived modSMCs expressed more aggrecan ( Acan ) and sclerostin ( Sost ) while small proteoglycans decorin ( Dcn ) and lumican ( Lum ) were enriched in SHF modSMCs. Insulin-like growth factor binding protein-2 ( Igfbp2 ) was a lineage-independent modSMC marker. RNA in situ hybridization localized Igfbp2 + SMCs within SHF/NC overlap in the aortic root. To study regional SMC propensity for modulation due to hemodynamic stresses, we generated aortic pressure overload via 27-gauge transverse aortic arch constriction (TAC) or sham surgery on healthy Myh11 cre / Rosa tdT (SMC-traced) mice. TAC induced mild root dilation vs . sham (1.93±0.07 mm vs. 1.69±0.09 mm, n=4, p<0.01). scRNAseq showed SMC phenotype modulation comparable to MFS in TAC mice and spatially concentrated in the aortic root. Conclusions: Embryologic origin does not dictate aortic SMC propensity for pathologic phenotype change in MFS but does promote distinct ECM proteoglycan gene activation. Aortic pressure overload incites root SMC modulation, suggesting hemodynamic effects may promote regional susceptibility to SMC-mediated aortic remodeling.

Microenvironmental Signatures Reveal Biological Subtypes of Diffuse Large B-Cell Lymphoma (DLBCL) Distinct from Tumor Cell Molecular Profiling

Research in DLBCL pathogenesis has largely focused on the lymphoma cells that defined molecular subtypes. To elucidate the role of the lymphoma microenvironment (LME) in this process, we developed and deconvoluted transcriptomics signatures of LME cells and pathways from 3,026 DLBCLs from 13 datasets including our new cohort of 127 pts. Mutations were available for 562 pts of the datasets and for 22 pts from our cohort (WES with matched normal). Applying density-based clustering we identified 4 LME signatures, independent of reported transcriptional and genetic classifications based on lymphoma cells: LME-1 DLBCLs (n=726, 24% - GCB/ABC: 35%/36%) were characterized by an "immunosuppressive" ME enriched for Tregs, myeloid-derived suppressor cells, CD8PD1high, natural killer and macrophages type 2 and prevalence of genetic mechanisms of immune escape in malignant cells such as mutations in B2M (33%) and CD70 (10%). Malignant cells in LME-1 DLBCL presented high activity of NF-kB and JAK/STAT signaling pathways, likely due to high frequency of co-occurring MYD88L265and CD79B mutations (40%) and the presence of a cytokine rich milieu including high expression of IL10, IL6 and TNFS13B. Good outcome genetic groups BN2 and EZB constituted 46% of pts LME-2 DLBCLs (n=484, 16% - GCB/ABC: 55%/30%) were characterized by an "anti-tumor immunity" ME enriched for T cells, follicular TH and follicular dendritic cells (FDC). Lymphoma cells presented the highest number of BCL2 translocations and EZH2 mutations (40%, p=0.001 vs. other LME groups) and activation of cell motility and chemotaxis pathways that likely account for the advance stage at presentation (70% were stages III/IV p=0.02 vs. 40-50% in the other LME groups). Lymphoma cells expressed higher levels of CCL20, CCR6 and CXCR5. Good outcome genetic groups BN2 and EZB constituted 74% of pts. Notably, ABC LME-2 DLBCLs had better prognosis that any other ABC DLBCL (p<0.007 n=848) and similar to GCB DLBCLs LME-3 DLBCLs (n=847, 28% - GCB/ABC: 56%/25%) were characterized by a "mesenchymal" ME enriched for cancer-associated fibroblasts (CAFs), reticular DC, FDC and endothelial cells. Lymphoma cells showed higher mutations in BCR/Pi3K signaling intermediates SGK1 and GNA13 (20 and 13%) and activation of the TGFB signaling and matrix remodeling pathways. LME-3 DLBCLs expressed higher levels of MMP9, MMP2, TIMP1 and TIMP2. Good outcome genetic groups BN2 and EZB constituted 75% of pts, and were no patients harboring NOTCH1 mutations. LME-3 DLBCL also had the higher proportion of non-cellular LME component represented by the extracellular matrix (ECM). Patients with DLBCL with higher ECM proportion had better progression free survival (p=0.0004). We specifically tested the ECM effect in a murine DLBCL model by analyzing changes in ECM proteins associated with disease progression by serial proteomics. DLBCL progression was accompanied by increase in lymphoma cells in detriment of CAFs and ECM proteins. Among them, we identified the small proteoglycan decorin (DCN). Accordingly, parental administration of recombinant DCN to DLBCL mice (n=10 vs vehicle n=10) decreased tumor volume (p<0.001) and lymphoma cell proliferation while improving the LME immune infiltrate LME-4 DLBCLs (n=969, 32% - GCB/ABC: 46%/38%) were characterized by a "depleted" ME with increased proportion of lymphoma cells with mutations in MYD88, PIM1 and HLA-C (36, 38 and 13%), higher genomic instability and epigenetic heterogeneity (by DNA methylation). Good outcome genetic groups BN2 and EZB constituted 68% of pts. Lymphoma cells showed activation of Pi3K signaling and hypermethylation and low expression of the TGFB mediator SMAD1 (p<0.01 vs other LME groups). In agreement with our demonstration that pharmacologically reversible SMAD1 hypermethylation drives chemoresistance in DLBCL (Cancer Discovery 2013), patients with LME-4 DLBCL had less favorable outcomes in overall survival (HR=1.65 P<0.005 n=1,980) and response to immunochemotherapy (p<0.0001 n=810) than any other LME groups; likely reflecting the acquisition of ME-autonomous survival mechanisms by lymphoma cells. The bad outcome of LME-4 DLBCLs was not dependent on MYC/BCL2 or BCL6 double translocations, or the overall mutational load. In sum, ME signatures in DLBCL associate with clinical outcomes independently of existing molecular subtypes, contribute to explain DLBCL biology and provide potential novel therapies Disclosures Rutherford: Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Honoraria; Verastem: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Heron: Consultancy, Honoraria; Janssen Scientific Affairs: Consultancy, Honoraria; Juno Therapeutics Inc: Consultancy, Honoraria. Martin:Celgene: Consultancy; Teneobio: Consultancy; Sandoz: Consultancy; I-MAB: Consultancy; Karyopharm: Consultancy; Janssen: Consultancy. Leonard:Nordic Nanovector: Consultancy; Nordic Nanovector: Consultancy; Miltenyi: Consultancy; MorphoSys: Consultancy; Merck: Consultancy; Miltenyi: Consultancy; Sandoz: Consultancy; Epizyme, Inc: Consultancy; AstraZeneca: Consultancy; AstraZeneca: Consultancy; Bayer Corporation: Consultancy; Bayer Corporation: Consultancy; ADC Therapeutics: Consultancy; Gilead: Consultancy; Karyopharm Therapeutics: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; Sutro Biopharma: Consultancy; Celgene: Consultancy; Gilead: Consultancy; BeiGene: Consultancy; Akcea Therapeutics: Consultancy; Sandoz: Consultancy; Akcea Therapeutics: Consultancy; BeiGene: Consultancy; MorphoSys: Consultancy; Sutro Biopharma: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; ADC Therapeutics: Consultancy; Celgene: Consultancy; Epizyme, Inc: Consultancy; Karyopharm Therapeutics: Consultancy; Merck: Consultancy.

Expression and localization of the small proteoglycans decorin and biglycan in articular cartilage of Kashin-Beck disease and rats induced by T-2 toxin and selenium deficiency.

Kashin-Beck disease (KBD) is an endemic degenerative osteoarthropathy of uncertain etiology. Our study sought to identify a correlation between small proteoglycans decorin and biglycan expression and Kashin-Beck Disease. Immunohistochemistry was used to assess the decorin and biglycan levels in cartilage specimens from both child KBD patients, and rats fed with T-2 toxin under a selenium-deficient condition. Real-time PCR and Western blot were used to assess mRNA and protein levels of decorin and biglycan in rat cartilages, as well as in C28/I2 chondrocytes stimulated by T-2 toxin and selenium in vitro. The result showed that decorin was reduced in all zones of KBD articular cartilage, while the expression of biglycan was prominently increased in KBD cartilage samples. Increased expression of biglycan and reduced expression of decorin were observed at mRNA and protein levels in the cartilage of rats fed with T-2 toxin and selenium- deficiency plus T-2 toxin diet, when compared with the normal diet group. Moreover, In vitro stimulation of C28/I2 cells with T-2 toxin resulted in an upregulation of biglycan and downregulation of decorin, T-2 toxin induction of biglycan and decorin levels were partly rescued by selenium supplement. This study highlights the focal nature of the degenerative changes that occur in KBD cartilage and may suggest that the altered expression pattern of decorin and biglycan have an important role in the onset and pathogenesis of KBD.

Recombinant fibromodulin and decorin effects on NF-κB and TGFβ1 in the 4T1 breast cancer cell line.

Constitutive activation of nuclear factor-κB (NF-κB) stimulates cell proliferation and metastasis, and inhibits apoptosis in breast cancer. Transforming growth factor-β (TGF-β) signaling pathway is deregulated in breast cancer progression and metastasis. The aim of the present study was to investigate the inhibitory effects of the two small leucine rich proteoglycans fibromodulin (Fmod) and decorin (Dcn), overexpressed using adenovirus gene transfer, on NF-κB-activity and TGF-β1-expression in the highly metastatic 4T1 breast cancer cell line. The results demonstrate that Fmod and Dcn overexpression is associated with NF-κB and TGF-β1 downregulation, and that Fmod promotes this effect more effectively compared with Dcn.

Supramolecular hydrogel networks formed by molecular recognition of collagen and a peptide grafted to hyaluronic acid

The extracellular matrix (ECM) is a nano-structured, highly complex hydrogel, in which the macromolecules are organized primarily by non-covalent interactions. Here, in a biomimetic approach, the decorin-derived collagen-binding peptide LSELRLHNN was grafted to hyaluronic acid (HA) in order to enable the formation of a supramolecular hydrogel network together with collagen. The storage modulus of a mixture of collagen and HA was increased by more than one order of magnitude (G′=157Pa) in the presence of the HA-grafted peptide compared to a mixture of collagen and HA (G′=6Pa). The collagen fibril diameter was decreased, as quantified using electron microscopy, in the presence of the HA-grafted peptide. Here, the peptide mimicked the function of decorin by spatially organizing collagen. The advantage of this approach is that the non-covalent crosslinks between collagen molecules and the HA chains created by the peptide form a reversible and dynamic hydrogel, which could be employed for a diverse range of applications in regenerative medicine. Statement of SignificanceBiopolymers of the extracellular matrix (ECM) like collagen or hyaluronan are attractive starting materials for biomaterials. While in biomaterial science covalent crosslinking is often employed, in the native ECM, stabilization and macromolecular organization is primarily based on non-covalent interactions, which allows dynamic changes of the materials. Here, we show that collagen-binding peptides, derived from the small proteoglycan decorin, grafted to hyaluronic acid enable supramolecular stabilization of collagen hydrogels. These hydrogels have storage moduli more than one order of magnitude higher than mixtures of collagen and hyaluronic acid. Furthermore, the peptide supported the structural organization of collagen. Such hydrogels could be employed for a diverse range of applications in regenerative medicine. Furthermore, the rational design helps in the understanding ECM structuring.

Grape seed extracts inhibit dentin matrix degradation by MMP-3.

Since Matrix metalloproteinases (MMPs) have been suggested to contribute to dentin caries progression, the hypothesis that MMP inhibition would affect the progression of dentin caries is clinically relevant. Grape seed extracts (GSE) have been previously reported to be natural inhibitors of MMPs.Objective: To evaluate the capacity of a GSE mouthrinse to prevent the degradation of demineralized dentin matrix by MMP-3 (stromelysin-1).Materials and Methods: Standardized blocks of dentin obtained from sound permanent teeth extracted for orthodontic reasons were demineralized with Ethylenediaminetetraacetic acid (EDTA) and pretreated either with (A) GSE (0.2% w/v), (B) amine fluoride (AmF) (20% w/v), (C) a mouthrinse which contains both, (D) placebo, (E) sodium fluoride (0.15 mg.ml−1), (F) PBS, (G) Chlorhexidine digluconate (CHX), or (H) zinc chloride (ZnCl2). The dentin blocks were then incubated with activated recombinant MMP-3. The supernatants were analyzed by Western Blot for several dentin matrix proteins known to be MMP-3 substrate. In parallel, scanning electron microscopy (SEM) was performed on resin replica of the dentin blocks.Results: Western blot analysis of the supernatants revealed that MMP-3 released from the dentin matrix small proteoglycans (decorin and biglycan) and dentin sialoprotein (DSP) in the AmF, sodium fluoride, PBS and placebo pretreated groups, but not in the GSE and mouthrinse pretreated groups. SEM examination of resin replica showed that the mouthrinse and its active components not only had an anti-MMP action but also modified the dentin surface accessibility.Conclusion: This study shows that GSE either alone or combined with AmF as in the evaluated mouthrinse limits dentin matrix degradation. This association may be promising to prevent the progression of caries within dentin. However, the procedure should be adapted to clinically relevant durations.

Excessive transforming growth factor-β signaling is a common mechanism in osteogenesis imperfecta.

Osteogenesis Imperfecta (OI) is a heritable disorder of connective tissue characterized by brittle bones, fractures and extraskeletal manifestations1. How structural mutations of type I collagen (dominant OI) or of its post-translational modification machinery (recessive OI) can cause abnormal quality and quantity of bone is poorly understood. Notably, the clinical overlap between dominant and recessive forms of OI suggests common molecular pathomechanisms2. Here, we show that excessive transforming growth factor-beta (TGFβ) signaling is a mechanism of OI in both recessive (Crtap−/−) and dominant (Col1a2tm1.1Mcbr) OI mouse models. In the skeleton, we find higher expression of TGFβ target genes, ratio of pSmad2/Smad2 protein, and in vivo Smad2 reporter activity. Anti-TGFβ treatment using the neutralizing antibody 1D11 corrects the bone phenotype in both forms of OI, and improves the lung abnormalities in Crtap−/− mice. Moreover, type I collagen of Crtap−/− mice shows reduced binding to the small leucine rich proteoglycan decorin, a known regulator of TGFβ activity3–4. Hence, altered TGFβ matrix-cell signaling is a primary mechanism in the pathogenesis of OI, and could be a promising target for the treatment of OI.

Characterization of Human Anulus Fibrosus– and Nucleus Pulposus–Derived Cells During Monolayer Expansion and in Hydrogel Cultures

In vitro-expanded intervertebral disc (IVD) cells could be a source for disc repair. However, IVD cell characterization still remains challenging and is demanded to detect phenotypical shifts. Therefore, the aim of the present study was to determine IVD cell expression profile during two- and three-dimensional culturing in direct comparison to in situ conditions. Human IVD tissue was analyzed immunohistologically and anulus fibrosus (AF) and nucleus pulposus (NP) cells were isolated and characterized for cytoskeletal architecture and expression of typical markers (type I, II, and III collagens, aggrecan, decorin, cartilage oligomeric protein, the chondrogenic transcription factor sox9, the tendon markers scleraxis and tenascin C) during 6 monolayer passages using real-time detection polymerase chain reaction and/or immunolabellings. Cells were introduced in alginate and collagen hydrogels and cell morphology and viablility was determined after 7 days. In addition to typical extracellular matrix components, IVD tissue and isolated cells revealed scleraxis expression. In early passages of cell expansion, genes of sox9, scleraxis, and the small proteoglycan decorin were expressed higher, but type I and III collagen genes were expressed lower in NP cells compared with AF cells. However, in passage 6, actin stress fibers increased and the expression levels of sox9 were nearly similar in NP and AF cells. The immunolabeling indicated that the fibroblast marker tenascin C could only be detected in vitro in both cell types but not in situ. Decorin protein expression decreased in both cell types in vitro in passage 6. IVD cells survived in both hydrogel cultures, and some cells elongated in collagen gels.

Localization of decorin gene expression in normal human breast tissue and in benign and malignant tumors of the human breast

The small extracellular matrix proteoglycan decorin which possesses a potent antitumor activity has been shown to be present in various amounts in the stroma of several tumors including those of the breast. Regarding decorin in breast malignancies the published data are conflicting, i.e., whether breast cancer cells express it or not. Here, we first compared decorin gene expression levels between healthy human breast tissue and selected types of human breast cancer using GeneSapiens databank. Next, we localized decorin mRNA in tissue specimen of normal human breast, intraductal breast papillomas and various histologic types of human breast cancer using in situ hybridization (ISH) with digoxigenin-labeled RNA probes for decorin. We also examined the effect of decorin transduction on the behavior of cultured human breast cancer MCF7 cells. Analysis of GeneSapiens databank revealed that in various human breast cancers decorin expression is significant. However, ISH results clearly demonstrated that human breast cancer cells independently of the type of the cancer do not express decorin mRNA. This was also true for papilloma-forming cells of the human breast. Indeed, decorin gene expression in healthy human breast tissue as well as in benign and malignant tumors of human breast was shown to take place solely in cells of the original stroma. Decorin transduction using decorin adenoviral vector in decorin-negative MCF7 cells resulted in a significant decrease in the proliferation of these cells and changed cell cohesion. Decorin-transduced MCF7 cells also exhibited increased apoptosis. In conclusion, our study shows that in human breast tissue only cells of the original stroma are capable of decorin gene expression. Our study also shows that transduction of decorin in decorin-negative human breast cancer cells markedly modulates the growth pattern of these cells.

Regional variations in the distribution and colocalization of extracellular matrix proteins in the juvenile bovine meniscus

A deeper understanding of the composition and organization of extracellular matrix molecules in native, healthy meniscus tissue is required to fully appreciate the degeneration that occurs in joint disease and the intricate environment in which an engineered meniscal graft would need to function. In this study, regional variations in the tissue-level and pericellular distributions of collagen types I, II and VI and the proteoglycans aggrecan, biglycan and decorin were examined in the juvenile bovine meniscus. The collagen networks were extensively, but not completely, colocalized, with tissue-level organization that varied with radial position across the meniscus. Type VI collagen exhibited close association with large bundles composed of type I and II collagen and, in contrast to type I and II collagen, was further concentrated in the pericellular matrix. Aggrecan was detected throughout the inner region of the meniscus but was restricted to the pericellular matrix and sheaths of collagen bundles in the middle and outer regions. The small proteoglycans biglycan and decorin exhibited regional variations in staining intensity but were consistently localized in the intra- and/or peri-cellular compartments. These results provide insight into the complex hierarchy of extracellular matrix organization in the meniscus and provide a framework for better understanding meniscal degeneration and disease progression and evaluating potential repair and regeneration strategies.

Proteomics Characterization of Extracellular Space Components in the Human Aorta

The vascular extracellular matrix (ECM) is essential for the structural integrity of the vessel wall and also serves as a substrate for the binding and retention of secreted products of vascular cells as well as molecules coming from the circulation. Although proteomics has been previously applied to vascular tissues, few studies have specifically targeted the vascular ECM and its associated proteins. Thus, its detailed composition remains to be characterized. In this study, we describe a methodology for the extraction of extracellular proteins from human aortas and their identification by proteomics. The approach is based on (a) effective decellularization to enrich for scarce extracellular proteins, (b) successful solubilization and deglycosylation of ECM proteins, and (c) relative estimation of protein abundance using spectral counting. Our three-step extraction approach resulted in the identification of 103 extracellular proteins of which one-third have never been reported in the proteomics literature of vascular tissues. In particular, three glycoproteins (podocan, sclerostin, and agrin) were identified for the first time in human aortas at the protein level. We also identified extracellular adipocyte enhancer-binding protein 1, the cartilage glycoprotein asporin, and a previously hypothetical protein, retinal pigment epithelium (RPE) spondin. Moreover, our methodology allowed us to screen for proteolysis in the aortic samples based on the identification of proteolytic enzymes and their corresponding degradation products. For instance, we were able to detect matrix metalloproteinase-9 by mass spectrometry and relate its presence to degradation of fibronectin in a clinical specimen. We expect this proteomics methodology to further our understanding of the composition of the vascular extracellular environment, shed light on ECM remodeling and degradation, and provide insights into important pathological processes, such as plaque rupture, aneurysm formation, and restenosis.

Decreased gene expression of fibrillin‐1 in stress urinary incontinence

Studies to show impairments in the pelvic floor extracellular matrix (ECM) associated with stress urinary incontinence (SUI) has earlier been performed, but the results are contradictory. Collagen I and III, the elastin associated proteins fibrillin-1 and fibulin-5 and the small leucine-rich repeat proteoglycans (SLRPs) decorin, lumican and fibromodulin are involved in giving the tissue its mechanical properties. Their gene signals and tissue localizations were investigated. Para-urethral punch biopsies were obtained from 24 women, 12 pre- and 12 postmenopausals, during surgery for SUI. As controls, biopsies were collected from 14 women, 8 pre- and 6 postmenopausals, undergoing surgery for other benign conditions. The mRNA expression by real-time RT-PCR and protein localization by immunohistochemistry were analyzed concerning collagen I and III, the small leucine rich repeat proteoglycans (SLRPs) decorin, lumican and fibromodulin and the elastic fiber associated proteins fibulin-5 and fibrillin-1. Statistical comparisons controlled for age changes in gene expressions. A significant decrease in mRNA expression of fibrillin-1 was discovered in all SUI women compared to all controls, P = 0.03. All molecules were down-regulated by age, but no other differences between SUI and controls reached significance. All proteins were adequately expressed by immunohistochemistry. A weaker staining for fibrillin-1 was seen in the pre-menopausal SUI group compared to the pre-menopausal controls. A decreased gene signal and weaker immunoreactivity for fibrillin-1, important for the elastic fiber assembly, was discovered in women with SUI. Loss of tissue elasticity could lead to increased urethra hypermobility and SUI.

Serum Amyloid A, but Not C-Reactive Protein, Stimulates Vascular Proteoglycan Synthesis in a Pro-Atherogenic Manner

Inflammatory markers serum amyloid A (SAA) and C-reactive protein (CRP) are predictive of cardiac disease and are proposed to play causal roles in the development of atherosclerosis, in which the retention of lipoproteins by vascular wall proteoglycans is critical. The purpose of this study was to determine whether SAA and/or CRP alters vascular proteoglycan synthesis and lipoprotein retention in a pro-atherogenic manner. Vascular smooth muscle cells were stimulated with either SAA or CRP (1 to 100 mg/L) and proteoglycans were then isolated and characterized. SAA, but not CRP, increased proteoglycan sulfate incorporation by 50 to 100% in a dose-dependent manner (P < 0.0001), increased glycosaminoglycan chain length, and increased low-density lipoprotein (LDL) binding affinity (K(d), 29 microg/ml LDL versus 90 microg/ml LDL for SAA versus control proteoglycans; P < 0.005). Furthermore, SAA up-regulated biglycan via the induction of endogenous transforming growth factor (TGF)-beta. To determine whether SAA stimulated proteoglycan synthesis in vivo, ApoE(-/-) mice were injected with an adenovirus expressing human SAA-1, a null virus, or saline. Mice that received adenovirus expressing SAA had increased TGF-beta concentrations in plasma and increased aortic biglycan content compared with mice that received either null virus or saline. Thus, SAA alters vascular proteoglycans in a pro-atherogenic manner via the stimulation of TGF-beta and may play a causal role in the development of atherosclerosis.

An Antimetastatic Role for Decorin in Breast Cancer

Decorin, a member of the small leucine-rich proteoglycan gene family, down-regulates members of the ErbB receptor tyrosine kinase family and attenuates their signaling, leading to growth inhibition. We investigated the effects of decorin on the growth of ErbB2-overexpressing mammary carcinoma cells in comparison with AG879, an established ErbB2 kinase inhibitor. Cell proliferation and anchorage-independent growth assays showed that decorin was a potent inhibitor of breast cancer cell growth and a pro-apoptotic agent. When decorin and AG879 were used in combination, the inhibitory effect was synergistic in proliferation assays but only additive in both colony formation and apoptosis assays. Active recombinant human decorin protein core, AG879, or a combination of both was administered systemically to mice bearing orthotopic mammary carcinoma xenografts. Primary tumor growth and metabolism were reduced by approximately 50% by both decorin and AG879. However, no synergism was observed in vivo. Decorin specifically targeted the tumor cells and caused a significant reduction of ErbB2 levels in the tumor xenografts. Most importantly, systemic delivery of decorin prevented metastatic spreading to the lungs, as detected by novel species-specific DNA detection and quantitative assays. In contrast, AG879 failed to have any effect. Our data support a role for decorin as a powerful and effective therapeutic agent against breast cancer due to its inhibition of both primary tumor growth and metastatic spreading.

Extracellular Matrix of Porcine Pericardium: Biochemistry and Collagen Architecture

Pericardial tissue has been used to construct bioprostheses employed in the repair of different kinds of injuries, mostly cardiac. However, calcification and mechanical failure have been the main causes of the limited durability of cardiac bioprostheses constructed with bovine pericardium. In the course of this work, a study was conducted on porcine fibrous pericardium, its microscopic structure and biochemical nature. The general morphology and architecture of collagen were studied under conventional light and polarized light microscopy. The biochemical study of the pericardial matrix was conducted according to the following procedures: swelling test, hydroxyproline and collagen dosage, quantification of amino acids in soluble collagen, component extraction of the extracellular matrix of the right and left ventral regions of pericardium with different molarities of guanidine chloride, protein and glycosaminoglycan (GAG) dosage, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and total GAG analysis. Microscopic analysis showed collagen fibers arranged in multidirectionally oriented layers forming a closely knit web, with a larger number of fibers obliquely oriented, initiating at the lower central region toward the upper left lateral relative to the heart. No qualitative differences were found between proteins extracted from the right and left regions. Likewise, no differences were found between fresh and frozen material. Protein dosages from left frontal and right frontal pericardium regions showed no significant differences. The quantities of extracted GAGs were too small for detection by the method used. Enzymatic digestion and electrophoretic analysis showed that the GAG found is possibly dermatan sulfate. The proteoglycan showed a running standard very similar to the small proteoglycan decorin.

Cellular and molecular pathology of HTS: basis for treatment

Hypertrophic scar and keloids are fibroproliferative disorders of the skin which occur often unpredictably, following trauma and inflammation that compromise cosmesis and function and commonly recur following surgical attempts for improvement. Despite decades of research in these fibrotic conditions, current non-surgical methods of treatment are slow, inconvenient and often only partially effective. Fibroblasts from these conditions are activated to produce extracellular matrix proteins such as collagen I and III, proteoglycans such as versican and biglycan and growth factors, including transforming growth factor-beta and insulin like growth factor I. However, more consistently these cells produce less remodeling enzymes including collagenase and other matrix metalloproteinases, as well as the small proteoglycan decorin which is important for normal collagen fibrillogenesis. Recently, the systemic response to injury appears to influence the local healing process whereby increases in Th2 and possibly Th3 cytokines such as IL-2, IL-4 and IL-10 and TGF-beta are present in the circulating lymphocytes in these fibrotic conditions. Finally, unique bone marrow derived cells including mesenchymal and endothelial stem cells as well as fibrocytes appear to traffic into healing wounds and influence the healing tissue. On this background, clinicians are faced with patients who require treatment and the pathophysiologic basis as currently understood is reviewed for a number of emerging modalities.

Altered extracellular matrix transcript expression and protein modulation in primary Duchenne muscular dystrophy myotubes

Extent of muscle fibrosis contributes to disease severity in muscular dystrophies. To investigate whether extracellular matrix (ECM) components contribute to the severe fibrosis observed in Duchenne muscular dystrophy (DMD) skeletal muscle, we quantitated several ECM components (transcripts and proteins) in primary DMD and control myotube cultures. We evaluated the fibrogenic transforming growth factor- β1 (TGF-β1); the small pleiotropic proteoglycan decorin, involved in collagen fibrillogenesis and TGF-β1 modulation; metalloproteinases MMP-2 and MMP-9; tissue inhibitors of metalloproteinase (TIMP) 1, 2 and 3; collagens I and VI; and the tissue factor myostatin that inhibits muscle growth. Dystrophic myotube cultures had significantly lower levels of decorin mRNA, as also observed in DMD muscle biopsies, and significantly higher levels of TGF-β1, myostatin, and collagens I and VI. MMP-2, TIMP-1 and TIMP-2 transcript levels were also significantly increased in DMD, but MMP-9 and TIMP-3 transcripts were unchanged. By zymography, MMP-2 activity was significantly higher in DMD than control. Protein levels were similar in DMD and controls but myostatin protein was significantly increased in DMD. We have found that transcript expression and protein modulation of several ECM components is altered in DMD muscle cells in vitro, indicating that these cells contribute fundamentally to the pathological process, since the inflammation and degeneration characterizing DMD muscle in vivo are presumably absent in culture. Our findings that myostatin-potent inhibitor of satellite cell activation and muscle renewal — is increased, and that decorin-binder and downregulator of TGFβ1 and myostatin — is decreased, may have implications for DMD therapy to reduce muscle fibrosis.

Structural correlations in the family of small leucine-rich repeat proteins and proteoglycans

The family of small leucine-rich repeat proteins and proteoglycans (SLRPs) contains several extracellular matrix molecules that are structurally related by a protein core composed of leucine-rich repeats (LRRs) flanked by two conserved cysteine-rich regions. The small proteoglycan decorin is the archetypal SLRP. Decorin is present in a variety of connective tissues, typically “decorating” collagen fibrils, and is involved in important biological functions, including the regulation of the assembly of fibrillar collagens and modulation of cell adhesion. Several SLRPs are known to regulate collagen fibrillogenesis and there is evidence that they may share other biological functions. We have recently determined the crystal structure of the protein core of decorin, the first such determination of a member of the SLRP family. This structure has highlighted several correlations: (1) SLRPs have similar internal repeat structures; (2) SLRP molecules are far less curved than an early model of decorin based on the three-dimensional structure of ribonuclease inhibitor; (3) the N-terminal and C-terminal cysteine-rich regions are conserved capping motifs. Furthermore, the structure shows that decorin dimerizes through the concave surface of its LRR domain, which has been implicated previously in its interaction with collagen. We have established that both decorin and opticin, another SLRP, form stable dimers in solution. Conservation of residues involved in decorin dimerization suggests that the mode of dimerization for other SLRPs will be similar. Taken together these results suggest the need for reevaluation of currently accepted models of SLRP interaction with their ligands.

Distribution of small proteoglycans and glycosaminoglycans in humerus-related articular cartilage of chickens

The expression of components present in the cartilaginous extracellular matrix is related to development, gender, and genotype, as well as to the biomechanical properties of each type of cartilage. In the present study, we analyzed small proteoglycans and glycosaminoglycans present in different cartilages of the chicken wing after extraction with guanidine hydrochloride or papain. Quantitative analysis of glycosaminoglycans showed a larger amount in humeral cartilage (around 200 mg/g tissue) than in articular cartilage of the radius and ulna, with 138 and 80 mg/g tissue, respectively. Non-collagenous proteins isolated were predominantly from cartilage in the proximal regions of the humerus and radius. D4 fractions obtained by ultracentrifugation were separated by DEAE-Sephacel and Octyl-Sepharose chromatography and analyzed by SDS-PAGE. Two bands of 57 and 70-90 kDa were observed for all samples treated with beta-mercaptoethanol. Immunoblotting of these proteins was positive for the small proteoglycans fibromodulin and decorin, respectively. Apparently, the 57-kDa protein is present in macromolecular complexes of 160 and 200 kDa. Chondroitin sulfate was detected in all regions. HPLC analysis of the products formed by chondroitinase AC and ABC digestion mainly revealed beta-D-glucuronic acid and N-acetyl beta-D-galactosamine residues. The 4-sulfation/6-sulfation ratio was close to 3, except for the proximal cartilage of the radius (2.5). These results suggest functional differences between the scapula-humerus, humerus-ulna, and humerus-radius joints of the chicken wing. This study contributes to the understanding of the physiology of cartilage and joints of birds under different types of mechanical stress.