Dysregulation of circulating collagen turnover markers in very early systemic sclerosis.

OBJECTIVE: Clinical observation suggests that vascular activation and autoimmunity precede remodelling of the extracellular matrix (ECM) in systemic sclerosis (SSc). We challenge this paradigm by hypothesising that ECM biomarkers are already disturbed in patients with very early SSc (veSSc) when fibrosis is not yet clinically detectable. METHODS: 42 patients with veSSc, defined as the presence of Raynaud's phenomenon and at least one of puffy fingers, positive antinuclear antibodies or pathological nailfold capillaroscopy, not meeting the 2013 American College of Rheumatology/European Alliance of Associations for Rheumatology classification criteria for SSc, were compared with healthy controls (HCs, n=29). ECM degradation (BGM, C3M, C4M and C6M) and ECM formation biomarkers (PRO-C3, PRO-C4 and PRO-C5) were measured in serum using ELISAs. A cross-sectional analysis at baseline and a longitudinal analysis was performed. RESULTS: Compared with HC, veSSc patients showed a strongly dysregulated turnover of type III and IV collagens (higher C3M, C4M, both p<0.0001 and PRO-C3, p=0.004, lower turnover ratios PRO-C3/C3M and PRO-C4/C4M, both p<0.0001). The biglycan degradation biomarker BGM was higher in veSSc than in HC (p=0.006), whereas the degradation biomarker for type VI collagen, C6M, was lower (p=0.002). In an ROC analysis, biomarkers of type III and IV collagen excellently distinguished between veSSc and HC: C3M, AUC=0.95, p<0.0001; C4M, AUC=0.97, p<0.0001; turnover ratios PRO-C3/C3M, AUC=0.80, p<0.0001; PRO-C4/C4M, AUC=0.97; p<0.0001. CONCLUSION: These findings indicate ECM remodelling as a very early phenomenon of SSc occurring in parallel with microvascular and autoimmune changes. Biomarkers of type III and IV collagens distinguished between veSSc patients and HC, indicating them as potential biomarkers for the detection of veSSc.

Associations of Adipocyte-derived Versican and Macrophage-derived Biglycan with Body Adipose Tissue and Hepatosteatosis in Obese Children

Objective: In animal models of obesity, adipocyte-derived versican, and macrophage-derived biglycan play a crucial role in mediating adipose tissue inflammation. The aim was to investigate levels of versican and biglycan in obese children and any potential association with body adipose tissue and hepatosteatosis. Methods: Serum levels of versican, biglycan, interleukin-6 (IL-6), and high sensitivity C-reactive protein (hsCRP) were measured by ELISA. Fat deposition in the liver, spleen, and subcutaneous adipose tissue was calculated using the IDEAL-IQ sequences in magnetic resonance images. Bioimpedance analysis was performed using the Tanita BC 418 MA device. Results: The study included 36 obese and 30 healthy children. The age of obese children was 13.6 (7.5-17.9) years, while the age of normal weight children was 13.0 (7.2-17.9) years (p=0.693). Serum levels of versican, hsCRP, and IL-6 were higher in the obese group (p=0.044, p=0.039, p=0.024, respectively), while no significant difference was found in biglycan levels between the groups. There was a positive correlation between versican, biglycan, hsCRP, and IL-6 (r=0.381 p=0.002, r=0.281 p=0.036, rho=0.426 p=0.001, r=0.424 p=0.001, rho=0.305 p=0.017, rho=0.748 p<0.001, respectively). Magnetic resonance imaging revealed higher segmental and global hepatic steatosis in obese children. There was no relationship between hepatic fat content and versican, biglycan, IL-6, and hsCRP. Versican, biglycan, hsCRP, and IL-6 were not predictive of hepatosteatosis. Body fat percentage >32% provided a predictive sensitivity of 81.8% and a specificity of 70.5% for hepatosteatosis [area under the curve (AUC): 0.819, p<0.001]. Similarly, a body mass index standard deviation score >1.75 yielded a predictive sensitivity of 81.8% and a specificity of 69.8% for predicting hepatosteatosis (AUC: 0.789, p<0.001). Conclusion: Obese children have higher levels of versican, hsCRP, and IL-6, and more fatty liver than their healthy peers.

Proteoglycan Remodeling Is Accelerated in Females with Angina Pectoris and Diffuse Myocardial Fibrosis: the iPOWER Study.

Angina and no obstructive coronary artery disease (CAD) have an unfavorable prognosis, possibly due to diffuse myocardial fibrosis (DMF). In DMF the proteoglycans biglycan and versican are actively remodeled by matrix metalloproteinase. We investigated biglycan and versican in females with angina and possible DMF assessed by cardiac magnetic resonance (CMR). Seventy-one females with angina and no obstructive CAD were included. Asymptomatic females served as controls. Versican and biglycan were measured and CMR was performed measuring extracellular volume. Biglycan and versican levels were higher in symptomatic females compared with controls; 31.4 ng/mL vs. 16.4 ng/mL (p < 0.001) and 2.1 ng/mL vs. 1.8 ng/mL (p < 0.001) and moderately correlated to extracellular volume (r2 = 0.38, p<0.001 and r2 = 0.26, p = 0.015). Turnover of biglycan and versican was increased in angina females compared with controls and associated with extracellular volume, supporting a link between angina with no obstructive CAD and fibrotic remodeling.

Serum Decorin, Biglycan, and Extracellular Matrix Component Expression in Preterm Birth.

Preterm birth is a leading cause of infant morbidity and mortality. Decorin and biglycan are proteoglycans that play key roles in maintaining the connective tissue matrix and tensile strength of human fetal membranes and have been previously linked to PPROM. Extracellular matrix proteins, such as matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9), TIMP metallopeptidase inhibitor 1 (TIMP-1), TIMP metallopeptidase inhibitor 2 (TIMP-2), and collagen VI (COL-6), have also been linked to PPROM and may have utility in a serum-based screening model for this condition. To define the natural course of serum decorin and biglycan expression throughout the duration of healthy pregnancy, to explore patterns of serum decorin and biglycan expression in serum of asymptomatic women who go on to develop spontaneous preterm labor, and to investigate the potential role for matrix metalloproteinases, their inhibitors, and collagen VI in a serum-based screening model to predict PPROM. Serum decorin level decreases less than 1% per week, and serum biglycan decreases by 2.9% per week over the duration of healthy pregnancy. Serum decorin and biglycan concentrations do not differ in spontaneous preterm labor cases compared with those in controls. Mean concentrations of MMP-2, MMP-9, TIMP-1, TIMP-2, and COL-6 do not differ in PPROM cases compared with those in controls. We have demonstrated that serum decorin and biglycan concentrations remain stable throughout the duration of normal pregnancy and are not early indicators of preterm labor, while common MMPs, TIMPs, and collagen VI are not early indicators of PPROM.

Serum Decorin and Biglycan as Potential Biomarkers to Predict PPROM in Early Gestation.

Preterm birth is a leading cause of neonatal mortality in the US and globally, with preterm premature rupture of fetal membranes (PPROM) accounting for one third of preterm births. Currently no predictive diagnostics are available to precisely assess risk and potentially reduce the incidence of PPROM. Bigycan and decorin, the main proteoglycans present in human fetal membranes, are involved in the physiological maturation of fetal membranes as well as in the pathophysiology of preterm birth. The serum protein sex hormone-binding globulin (SHBG) has recently been identified as a predictor of spontaneous preterm birth. We hypothesize that the balance between serum decorin and biglycan on one hand and SHBG on the other hand may provide insight into the status of the fetal membranes in early pregnancy, thereby predicting PPROM prior to symptoms. Using chart review, 18 patients with confirmed cases of PPROM were identified from 2013-2016. Second trimester residual serum was retreived from freezer storage for these cases along with 5 matched controls for each case. The biomarkers biglycan, decorin and SHBG were analyzed first separately, then in combination to determine their ability to predict PPROM. The predictive score for the combined model displays an AUC = 0.774. The ROC curve of the predicted score has an optimal threshold of 0.238 and a sensitivity and specificity of 0.72 and 0.84 respectively. This prenatal serum panel is a promising serum screening-based biochemical model to predict PPROM in asymptomatic women.

Significance of biglycan and osteopontin as non-invasive markers of liver fibrosis in patients with chronic hepatitis B virus and chronic hepatitis C virus.

Several studies were performed to evaluate the degree of liver fibrosis by non-invasive markers. We aimed to assess the diagnostic value of both biglycan (BGN) and osteopontin (OPN) as non-invasive markers of hepatic fibrosis in patients with chronic hepatitis B (CHB) and chronic hepatitis C (CHC). This study was performed on 100 patients with CHB virus, 100 patients with CHC virus and 100 normal controls. All participants were subjected to the following laboratory tests: hemoglobin, platelet, alanine aminotransferase, aspartate aminotransferase, albumin, international normalized ratio, HBs Ag, hepatitis C virus (HCV) antibody, hepatitis B virus DNA, HCV RNA, liver biopsy, BGN and OPN. We found that BGN level was significantly increased in the CHB group compared with the controls (p<0.001), but the level was not different between the CHC group and the controls (p<0.96). OPN was increased in both the CHB and CHC groups compared with the controls (p<0.001). Positive correlation was found between fibrosis stages and BGN level of the CHB group (r=0.64; p<0.001) and between fibrosis stages and OPN level of the CHB (r=0.63; p<0.001) and CHC (r=0.59; p<0.03) groups. The area under the curve (AUC), sensitivity and specificity of BGN were 1.0, 100% and 100% in predicting fibrosis in patients with CHB, and 0.50, 26% and 78% in predicting fibrosis in patients with CHC. OPN had an AUC of 0.997, sensitivity of 96% and specificity of 100% in predicting fibrosis in patients with CHB, and 0.974, 96.5% and 100% in predicting fibrosis in patients with CHC. In conclusion, BGN and OPN could be considered non-invasive markers for liver fibrosis assessment.

Citrullinated vimentin and biglycan protein fingerprints as candidate serological biomarkers for disease activity in systemic sclerosis: a pilot study.

Purpose: Extracellular matrix (ECM) deposition and remodelling in skin and lungs of systemic sclerosis (SSc) subjects lead to release of metabolites/biomarkers into circulation. We investigated if biomarkers of ECM degradation (biglycan and elastin) and macrophage activation (citrullinated vimentin) could identify diffuse SSc (dSSc) subjects from controls and the biomarkers discriminative power. Methods: DSSc subjects (n = 40) fulfilling the 2013 EULAR/ACR classification criteria were divided in early (<2years of symptoms) and late (≥10 years of symptoms). Early were subdivided into intermediate and rapid skin thickness progression rate (STPR). Twenty controls were included. Citrullinated and matrix metalloproteinase (MMP)-2/8-degraded vimentin (VICM), MMP-9/12-degraded biglycan (BGM) and MMP-7-degraded elastin (ELM-7) were assessed in serum. Analysis between groups was by Kruskal-Wallis and ROC AUC for discriminative power. Results: VICM and BGM levels were increased in early compared with late dSSc (p< =0.023). VICM was increased in rapid and intermediate STPR compared with controls (p< =0.025). No differences in ELM-7 levels were observed. AUC of VICM was 0.71 for early versus late dSSc and BGM had an AUC of 0.79 for dSSc versus controls. Conclusion: This pilot study found differences in biomarker levels between early and late dSSc. This study offers new perspectives of ECM metabolites as potential biomarkers of dSSc.

Biglycan expression, earlier vascular damage and pro-atherogenic profile improvement after smoke cessation in young people.

BACKGROUND AND AIMS: Young cigarette smokers may already present with early signs of vascular inflammation and damage; biglycan (BGN) has been shown to play a critical role in the initiation and progression of vascular lesions, also in young smokers. We investigated whether after smoke cessation, monocyte BGN expression is reduced; moreover, we evaluated any improvement of pro-atherogenic profile and arterial stiffness (AS), and their relationship with BGN in abstinent smokers. METHODS: Two-hundred-fifty-one young people who had decided to quit smoking were enrolled; of these, 71 had completed the 12-month observation period maintaining smoking abstinence. At enrollment and 12 months later, we evaluated anthropometrics, laboratory profile, carotid-femoral pulse wave velocity (cf-PWV), carotid intima-media thickness (cIMT), BGN expression. RESULTS: After 12-month smoke abstinence, we found a significant decrease in inflammatory markers (Hs-CRP: -23.3%; fibrinogen: -11.8%; IL-6: -9.2%), and increased HDL-C levels (+9.3%); blood pressure values were also slightly reduced. cf-PWV (-8.9%) appeared to be improved; cIMT remained unchanged. BGN expression appeared to be reduced (-42.8% relative reduction). BGN reduction appeared to be associated with fibrinogen reduction, and smoking burden. Reduced cf-PWV appeared to be dependent on change in fibrinogen, SBP, IL-6, and BGN by multiple regression analysis. CONCLUSIONS: After the first year of smoke abstinence, the levels of IL-6, CRP, fibrinogen, HDL-C, and BGN expression, as well cf-PWV, are significantly improved as compared to baseline. This is the first evidence that removing exposure to a well-known cardiovascular risk factor, such as cigarette smoking, leads to significant reduction of BGN expression.

The importance of serum biglycan levels as a fibrosis marker in patients with chronic hepatitis B.

BACKGROUND: Liver biopsy is recommended in the majority of patients with chronic viral hepatitis for fibrosis evaluation. Because of the potential risks of liver biopsy, many studies related to non-invasive biomarkers of hepatic fibrosis have been performed. We aimed to assess the diagnostic value of serum biglycan as a non-invasive fibrosis marker in chronic hepatitis B patients. METHODS: This study included 120 patients with biopsy-proven hepatitis B patients and 60 healthy controls. Fibrosis stage and necroinflammatory activity were assessed in liver biopsy specimens. Biglycan level was measured using an ELISA assay. RESULTS: Serum biglycan levels of chronic hepatitis B patients were found to be significantly higher than those of healthy controls (337.3±363.0 pg/mL vs 189.1±61.9 pg/mL, respectively, P<.001). There was a statistically significant positive correlation between serum biglycan level and fibrosis stage (P=.004; r=.213). Besides, a statistically significant positive correlation was found between serum biglycan level and necroinflammatory activity (P<.001; r=.271). The AUROC of BGN levels was 0.702 for fibrosis stage, differentiating patients from healthy controls with statistical significance (P<.001). The AUROC of BGN levels was 0.632 for necroinflammatory activity score, differentiating patients from healthy controls with statistical significance (P=.004). CONCLUSIONS: Serum biglycan might be used as a non-invasive marker of liver fibrosis. Further studies are needed to evaluate the usefulness of this marker.

Loss of Biglycan Enhances Thrombin Generation in Apolipoprotein E-Deficient Mice: Implications for Inflammation and Atherosclerosis.

OBJECTIVE: Thrombin signaling promotes atherosclerosis by initiating inflammatory events indirectly through platelet activation and directly via protease-activated receptors. Therefore, endogenous thrombin inhibitors may be relevant modulators of atheroprogression and cardiovascular risk. In addition, endogenous thrombin inhibitors may affect the response to non-vitamin K-dependent oral anticoagulants. Here, the question was addressed whether the small leucine-rich proteoglycan biglycan acts as an endogenous thrombin inhibitor in atherosclerosis through activation of heparin cofactor II. APPROACH AND RESULTS: Biglycan concentrations were elevated in the plasma of patients with acute coronary syndrome and in male Apolipoprotein E-deficient (ApoE(-/-)) mice. Biglycan was detected in the glycocalyx of capillaries and the subendothelial matrix of arterioles of ApoE(-/-) mice and in atherosclerotic plaques. Thereby a vascular compartment is provided that may mediate the endothelial and subendothelial activation of heparin cofactor II through biglycan. ApoE and Bgn double-deficient (ApoE(-/-)/Bgn(-/0)) mice showed higher activity of circulating thrombin, increased platelet activation and platelet adhesion in vivo, supporting a role of biglycan in balancing thrombin activity. Furthermore, concentrations of circulating cytokines and aortic macrophage content were elevated in ApoE(-/-)/Bgn(-/0) mice, suggesting a proinflammatory phenotype. Elevated platelet activation and macrophage accumulation were reversed by treating ApoE(-/-)/Bgn(-/0) mice with the thrombin inhibitor argatroban. Ultimately, ApoE(-/-)/Bgn(-/0) mice developed aggravated atherosclerosis. CONCLUSIONS: The present results indicate that biglycan plays a previously unappreciated protective role during the progression of atherosclerosis by inhibiting thrombin activity, platelet activation, and finally macrophage-mediated plaque inflammation.

Novel extracellular matrix biomarkers as predictors of adverse outcome in chronic heart failure: association between biglycan and response to statin therapy in the CORONA trial.

BACKGROUND: The extracellular matrix (ECM) plays an important role in left ventricular remodeling and progression of heart failure (HF). Biglycan and mimecan are ECM proteins that are abundantly expressed in cardiac tissue but have not been evaluated as prognostic markers in HF. We investigated their interaction with statin treatment and association with adverse outcome in chronic HF. METHODS AND RESULTS: The association between serum levels of biglycan and mimecan and the primary end point (cardiovascular [CV] death, nonfatal myocardial infarction, nonfatal stroke), all-cause mortality, CV death, the composite of all-cause mortality/hospitalization for worsening of HF, and the coronary end point was evaluated in 1,390 patients >60 years of age with ischemic systolic HF in the Controlled Rosuvastatin Multinational Trial in HF (CORONA) population, randomly assigned to 10 mg rosuvastatin or placebo. Serum biglycan and mimecan added no prognostic information beyond conventional risk factors, including N-terminal pro-B-type natriuretic peptide. However, statin treatment improved all outcomes except CV death in patients with low biglycan levels (ie, lower tertile), even after full multivariable adjustment. CONCLUSIONS: Although circulating levels of mimecan and biglycan were of limited predictive value in patients with chronic HF, circulating biglycan could be a useful marker for targeting statin therapy in patients with HF.

Evaluation of a 4-protein serum biomarker panel-biglycan, annexin-A6, myeloperoxidase, and protein S100-A9 (B-AMP)-for the detection of esophageal adenocarcinoma.

BACKGROUND: Esophageal adenocarcinoma (EAC) is associated with a dismal prognosis. The identification of cancer biomarkers can advance the possibility for early detection and better monitoring of tumor progression and/or response to therapy. The authors present results from the development of a serum-based, 4-protein (biglycan, myeloperoxidase, annexin-A6, and protein S100-A9) biomarker panel for EAC. METHODS: A vertically integrated, proteomics-based biomarker discovery approach was used to identify candidate serum biomarkers for the detection of EAC. Liquid chromatography-tandem mass spectrometry analysis was performed on formalin-fixed, paraffin-embedded tissue samples that were collected from across the Barrett esophagus (BE)-EAC disease spectrum. The mass spectrometry-based spectral count data were used to guide the selection of candidate serum biomarkers. Then, the serum enzyme-linked immunosorbent assay data were validated in an independent cohort and were used to develop a multiparametric risk-assessment model to predict the presence of disease. RESULTS: With a minimum threshold of 10 spectral counts, 351 proteins were identified as differentially abundant along the spectrum of Barrett esophagus, high-grade dysplasia, and EAC (P<.05). Eleven proteins from this data set were then tested using enzyme-linked immunosorbent assays in serum samples, of which 5 proteins were significantly elevated in abundance among patients who had EAC compared with normal controls, which mirrored trends across the disease spectrum present in the tissue data. By using serum data, a Bayesian rule-learning predictive model with 4 biomarkers was developed to accurately classify disease class; the cross-validation results for the merged data set yielded accuracy of 87% and an area under the receiver operating characteristic curve of 93%. CONCLUSIONS: Serum biomarkers hold significant promise for the early, noninvasive detection of EAC.

Biglycan-triggered TLR-2- and TLR-4-signaling exacerbates the pathophysiology of ischemic acute kidney injury.

Exacerbated inflammation in renal ischemia-reperfusion injury, the major cause of intrinsic acute renal failure, is a key trigger of kidney damage. During disease endogenous danger signals stimulate innate immune cells via Toll-like receptors (TLR)-2 and -4 and accelerate inflammatory responses. Here we show that production of soluble biglycan, a small leucine-rich proteoglycan, is induced during reperfusion and that it functions as endogenous agonist of TLR-2/4. Biglycan-mediated activation of TLR-2/4 initiates an inflammatory response in native kidneys, which is marked by the release of cytokines and chemokines and recruitment of inflammatory cells. Overexpression of soluble circulating biglycan before ischemic reperfusion enhanced plasma and renal levels of TNF-α, CXCL1, CCL2 and CCL5, caused influx of neutrophils, macrophages and T cells and overall worsened renal function in wild type mice. We provide robust genetic evidence for TLR-2/4 requirement insofar as biglycan biological effects were markedly dampened in mice deficient in both innate immune receptors, Tlr2(-/-);Tlr4(-/-) mice. Thus, signaling of soluble biglycan via TLR-2/4 could represent a novel therapeutic target for the prevention and possible treatment of patients with acute renal ischemia-reperfusion injury.

De novo expression of circulating biglycan evokes an innate inflammatory tissue response via MyD88/TRIF pathways.

Matrix-bound constituents, such as the small leucine-rich proteoglycan biglycan, can act as powerful signaling molecules when released by limited proteolysis of the extracellular matrix or de novo synthesized by macrophages in the circulation and body fluids. Specifically, biglycan acts as an endogenous ligand of innate immunity by directly engaging the Toll-like receptor (TLR)-2 and -4. In this study, we generated a transient transgenic mouse model where biglycan was de novo overproduced by hepatocytes driven by the albumin promoter. Transgenic biglycan was rapidly and abundantly synthesized by hepatocytes and released into the bloodstream. Notably, we found that circulating biglycan accumulated in the kidneys where it caused recruitment of leukocytes infiltrating the renal parenchyma concurrent with abnormal renal levels of chemoattractants CXCL1, CXCL2, CCL2 and CCL5. Using mice deficient in either TLR adapter proteins MyD88 or TRIF we discovered that MyD88 deficiency drastically reduced neutrophil and macrophage infiltration in the kidney, whereas TRIF deficiency decreased T cell infiltrates. Production of CXCL1, CXCL2 and CCL2 required MyD88, whereas the levels of T cell and macrophage attractant CCL5 required TRIF. Thus, we provide robust genetic evidence for circulating biglycan as a powerful pro-inflammatory mediator targeting the renal parenchyma. Furthermore, our results provide the first evidence that biglycan differentially triggers chemoattraction of leukocytes via two independent pathways, both under the control of TLR2/4, utilizing either MyD88 or TRIF adaptor proteins. As aberrant expression of biglycan occurs in several inflammatory diseases, this transient transgenic mouse model could serve as a valuable research tool in investigating the effects of increased biglycan expression in vivo and for the development of therapeutic strategies in the treatment of inflammatory diseases.

Protein fingerprinting of the extracellular matrix remodelling in a rat model of liver fibrosis--a serological evaluation.

BACKGROUND/AIM: We investigated nine novel biomarkers of extracellular matrix (ECM) remodelling in a rat model of liver fibrosis. METHODS: Liver fibrosis was induced in 52 male Wistar rats by inhalation of carbon tetrachloride and the level of hepatic fibrosis was assessed by Sirius red staining compared with controls. The novel serum biochemical markers assessed in the model were type I-(C1M), type III-(C3M), type IV-(C4M) and type VI-(C6M) collagen, citrullinated vimentin (VICM) and biglycan (BGM) all protein fragments generated by matrix metalloproteinases; and formation markers of type III-(P3NP), type VI (P4NP 7S) and type V (P5CP) collagen; hepatic mRNA type I collagen alpha-1 chain levels, serum potassium, sodium, osmolarity, alanine aminotransferase, lactate dehydrogenase, albumin and creatinine. RESULTS: Stratification of the CCl(4) -treated rats according to total hepatic collagen showed that the degradation markers were significantly elevated in mild to severe fibrosis except for C6M which was also elevated in early fibrosis (P < 0.05). The highest Z-scores in early and moderate fibrosis were provided by P4NP 7S and alanine aminotransferase. All nine markers of ECM remodelling were highly related to the extent of liver fibrosis induced by CCl(4) . The novel collagen formation marker, P4NP 7S, was reliable for the detection of early fibrosis, while the combination of the two markers, C6M and P5CP provided the best correlation with hepatic fibrosis in all fibrosis levels. CONCLUSION: As the markers can be used for translational science, these markers may provide valuable information for the evaluation of liver fibrosis in clinical settings.

Biglycan is a specific marker and an autocrine angiogenic factor of tumour endothelial cells.

BACKGROUND: We isolated tumour endothelial cells (TECs), demonstrated their abnormalities, compared gene expression profiles of TECs and normal endothelial cells (NECs) by microarray analysis and identified several genes upregulated in TECs. We focused on the gene encoding biglycan, a small leucine-rich repeat proteoglycan. No report is available on biglycan expression or function in TECs. METHODS: The NEC and TEC were isolated. We investigated the biglycan expression and function in TECs. Western blotting analysis of biglycan was performed on sera from cancer patients. RESULTS: Biglycan expression levels were higher in TECs than in NECs. Biglycan knockdown inhibited cell migration and caused morphological changes in TECs. Furthermore, immunostaining revealed strong biglycan expression in vivo in human tumour vessels, as in mouse TECs. Biglycan was detected in the sera of cancer patients but was hardly detected in those of healthy volunteers. CONCLUSION: These findings suggested that biglycan is a novel TEC marker and a target for anti-angiogenic therapy.

The proteoglycan biglycan regulates expression of the B cell chemoattractant CXCL13 and aggravates murine lupus nephritis.

CXCL13 is a key B cell chemoattractant and marker of disease activity in patients with SLE; however, the mechanism of its induction has not been identified yet. Here, we have shown that the proteoglycan biglycan triggers CXCL13 expression via TLR2/4 in macrophages and dendritic cells. In vivo, levels of biglycan were markedly elevated in the plasma and kidneys of human SLE patients and lupus-prone (MRL/lpr) mice. Overexpression of soluble biglycan in MRL/lpr mice raised plasma and renal levels of CXCL13 and caused accumulation of B cells with an enhanced B1/B cell ratio in the kidney, worsening of organ damage, and albuminuria. Importantly, biglycan also triggered CXCL13 expression and B cell infiltration in the healthy kidney. Conversely, biglycan deficiency improved systemic and renal outcome in lupus-prone mice, with lower levels of autoantibodies, less enlargement of the spleen and lymph nodes, and reduction in renal damage and albuminuria. This correlated with a marked decline in circulating and renal CXCL13 and a reduction in the number of B cells in the kidney. Collectively, our results describe what we believe to be a novel mechanism for the regulation of CXCL13 by biglycan, a host-derived ligand for TLR2/4. Blocking biglycan-TLR2/4 interactions might be a promising strategy for the management of SLE and other B cell-mediated inflammatory disease entities.