The chitinase 3-like protein human cartilage glycoprotein 39 (HC-gp39) stimulates proliferation of human connective-tissue cells and activates both extracellular signal-regulated kinase- and protein kinase B-mediated signalling pathways

YKL-40 regulated epithelial-mesenchymal transition and migration/invasion enhancement in non-small cell lung cancer

Background

YKL-40 is a secreted inflammatory protein that its overexpression has been reported to correlate with poor outcome of various malignant diseases, especially in cancer. However, the function of this protein is still unclear.

Methods

The clinical prognosis of non-small cell lung cancers (NSCLC) patients and their clinical YKL-40 expressions were obtained from the Prognoscan database. The expressions of YKL-40 in patient samples were determined by Western Blotting assay. YKL-40 gene knockdown and overexpression were performed on NSCLC cancer cells (CL1-1 and CL1-5). The cells were investigated for their epithelial–mesenchymal transition (EMT) markers gene modulation through Western Blotting and RT-PCR. Further cell metastatic abilities were assessed by transwell migration and invasion assay.

Result

In this study, YKL-40 was observed to be highly expressed in NSCLC specimens. Furthermore, determined by the PrognoScan database analysis, patients with high expression levels of YKL-40 were found with poor prognosis. In the in vitro study, different characteristics of NSCLC cell lines (CL1-1, H23, H838, CL1-5, and H2009) were used as study models, where YKL-40 expression levels were determined to correlate with the phenotypic characteristics of cancer metastasis. In this study,YKL-40 was demonstrated to regulate EMT marker expressions such as Twist, Snail, Slug, N-cadherin, Vimentin, and E-cadherin. The protein’s affects in cancer cell migration and invasion were also observed in YKL-40 overexpression or knock down NSCLC cell lines.

Conclusion

All of results from this study suggest that YKL-40 is a major factor in NSCLC metastasis. Thus, YKL-40 may serve as therapeutic targets for NSCLC patients in the future.

YKL-40 level in gingival crevicular fluid from patients with periodontitis and type 2 diabetes

OBJECTIVE

YKL-40 is a chitin-binding glycoprotein, the level of which increases in inflammatory diseases, diabetes mellitus (DM), cardiovascular diseases, and tumors. Gingival crevicular fluid (GCF) contains many proteins and markers of periodontitis. The purpose of this study was to investigate YKL-40 level in GCF from patients with periodontitis and DM and the association between YKL-40 level and chronic periodontitis (CP) or DM.

SUBJECTS AND METHODS

The subjects were 121 patients with DM, CP, DM and periodontitis (DM-P), and healthy subjects (H). GCF was collected using paper strips after the sites for GCF collection were clinically evaluated for probing depth (PD), gingival index (GI), and bleeding on probing (BOP). YKL-40 in GCF was identified by Western blotting, and its level was determined by ELISA.

RESULTS

YKL-40 was contained in GCF samples from H, DM, CP, and DM-P sites, and its levels (amount and concentration) in CP and DM-P were significantly higher than those in H and DM. GCF YKL-40 level significantly correlated with PD and GI, and its level in BOP-positive sites was significantly higher than that in BOP-negative ones.

CONCLUSIONS

GCF YKL-40 level was elevated in periodontitis, but not DM. YKL-40 in GCF may be an inflammatory marker for periodontitis.

Keeping track of the growing number of biological functions of chitin and its interaction partners in biomedical research

Chitin is a vital polysaccharide component of protective structures in many eukaryotic organisms but seems absent in vertebrates. Chitin or chitin oligomers are therefore prime candidates for non-self-molecules, which are recognized and degraded by the vertebrate immune system. Despite the absence of polymeric chitin in vertebrates, chitinases and chitinase-like proteins (CLPs) are well conserved in vertebrate species. In many studies, these proteins have been found to be involved in immune regulation and in mediating the degradation of chitinous external protective structures of invading pathogens. Several important aspects of chitin immunostimulation have recently been uncovered, advancing our understanding of the complex regulatory mechanisms that chitin mediates. Likewise, the last few years have seen large advances in our understanding of the mechanisms and molecular interactions of chitinases and CLPs in relation to immune response regulation. It is becoming increasingly clear that their function in this context is not exclusive to chitin producing pathogens, but includes bacterial infections and cancer signaling as well. Here we provide an overview of the immune signaling properties of chitin and other closely related biomolecules. We also review the latest literature on chitinases and CLPs of the GH18 family. Finally, we examine the existing literature on zebrafish chitinases, and propose the use of zebrafish as a versatile model to complement the existing murine models. This could especially be of benefit to the exploration of the function of chitinases in infectious diseases using high-throughput approaches and pharmaceutical interventions.

Lipo-chitin oligosaccharides, plant symbiosis signalling molecules that modulate mammalian angiogenesis in vitro

Lipochitin oligosaccharides (LCOs) are signaling molecules required by ecologically and agronomically important bacteria and fungi to establish symbioses with diverse land plants. In plants, oligo-chitins and LCOs can differentially interact with different lysin motif (LysM) receptors and affect innate immunity responses or symbiosis-related pathways. In animals, oligo-chitins also induce innate immunity and other physiological responses but LCO recognition has not been demonstrated. Here LCO and LCO-like compounds are shown to be biologically active in mammals in a structure dependent way through the modulation of angiogenesis, a tightly-regulated process involving the induction and growth of new blood vessels from existing vessels. The testing of 24 LCO, LCO-like or oligo-chitin compounds resulted in structure-dependent effects on angiogenesis in vitro leading to promotion, or inhibition or nil effects. Like plants, the mammalian LCO biological activity depended upon the presence and type of terminal substitutions. Un-substituted oligo-chitins of similar chain lengths were unable to modulate angiogenesis indicating that mammalian cells, like plant cells, can distinguish between LCOs and un-substituted oligo-chitins. The cellular mode-of-action of the biologically active LCOs in mammals was determined. The stimulation or inhibition of endothelial cell adhesion to vitronectin or fibronectin correlated with their pro- or anti-angiogenic activity. Importantly, novel and more easily synthesised LCO-like disaccharide molecules were also biologically active and de-acetylated chitobiose was shown to be the primary structural basis of recognition. Given this, simpler chitin disaccharides derivatives based on the structure of biologically active LCOs were synthesised and purified and these showed biological activity in mammalian cells. Since important chronic disease states are linked to either insufficient or excessive angiogenesis, LCO and LCO-like molecules may have the potential to be a new, carbohydrate-based class of therapeutics for modulating angiogenesis.

Comparative effects of metformin and pioglitazone on YKL-40 in type 2 diabetes: a randomized clinical trial

PURPOSE

Metformin and pioglitazone are believed to exert their long-term benefits by means of amelioration of chronic low-grade inflammation, a key event in development of diabetes and its long-term complications. The present trial was designed to investigate the comparative efficacy of the two anti-diabetes medications on serum concentrations of YKL-40, a novel marker of inflammation.

METHODS

In a parallel-group, open-label, randomized trial setting (ClinicalTrials.gov Identifier No. NCT01521624), 84 newly diagnosed, medication-naïve type 2 diabetes patients were assigned to metformin 1,000 mg daily (n = 42) or pioglitazone 30 mg daily (n = 42). Serum concentrations of YKL-40, along with highly sensitive C-reactive protein, indices of glycemic control and lipid profile were measured at baseline and after 3 months.

RESULTS

In the analyzed sample (metformin = 40, pioglitazone = 42), both medications were equally effective with regard to control of hyperglycemia, and hsCRP reduction (p > 0.05). However, metformin caused a significant decline in weight (p = 0.005), BMI (p = 0.004), and total cholesterol levels (p = 0.028) of the patients. Metformin also significantly reduced YKL-40 concentrations after 3 months (1.90 ± 17 vs. 1.66 ± 0.15 µg/L, p = 0.019). The amount of change in the pioglitazone arm did not reach statistical significance (2.18 ± 0.14 vs. 2.25 ± 0.16 µg/L, p = 0.687). When compared, metformin was significantly more effective than pioglitazone with respect to YKL-40 reduction in both univariate (p = 0.020, effect size = 6.7%) and multivariate models (p = 0.047, effect size = 5.7%).

CONCLUSIONS

Metformin is more effective in reduction of YKL-40 concentration in short term and the effect seems to be independent of degree of glycemic control, or hsCRP reduction.

Plasma YKL-40 in Inuit and Danes

AIMS

The aim of the present study was to investigate whether there are differences in plasma levels of YKL-40 between Inuit in Greenland and in Denmark and in Danes, as well as to study the relationship between alcohol intake, plasma YKL-40 and other factors in Inuit.

METHODS

Plasma YKL-40 levels were measured on 1645 people from The Greenland Population Study (a cross-sectional population study of Inuit from Denmark and West Greenland) and were compared with the plasma YKL-40 levels of 8899 people from The Copenhagen City Heart Study (a population-based, prospective study of the Danish general population).

RESULTS

The plasma concentrations of YKL-40 were significantly (P = 0.001) lower in Inuit living in Greenland (median 46 µg/l, range 10-2164, n = 1164) compared with the plasma YKL-40 levels of Inuit living in Denmark (median 63 µg/l, range 20-2827, n = 481) and of Danes living in Denmark (median 55 µg/l, range 10-2909, n = 8899). In Inuit, increased alcohol intake was significantly associated with increased plasma YKL-40 levels (P < 0.001), and high plasma YKL-40 levels were associated with high values of alkaline phosphatase and low values of albumin. Smoking, gender and bilirubin were not associated with the plasma YKL-40 level. High levels of YKL-40 and alcohol were associated with where people lived.

CONCLUSION

The plasma concentrations of YKL-40 are significantly lower in Inuit living in Greenland than Inuit and Danes living in Denmark. A number of factors, including different alcohol intake patterns, nutrition and genes may play a role in these findings.

New treatment and markers of prognosis for idiopathic pulmonary fibrosis: lessons learned from translational research

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease with increasing prevalence, high mortality rates and poor treatment options. The diagnostic process is complex and often requires an interdisciplinary approach between different specialists. Information gained over the past 10 years of intense research resulted in improved diagnostic algorithms, a better understanding of the underlying pathogenesis and the development of new therapeutic options. Specifically, the change from the traditional concept that viewed IPF as a chronic inflammatory disorder to the current belief that is primarily resulting from aberrant wound healing enabled the identification of novel treatment targets. This increased the clinical trial activity dramatically and resulted in the approval of the first IPF-specific therapy in many countries. Still, the natural history and intrinsic behavior of IPF are very difficult to predict. There is an urgent need for new therapies and also for development and validation of prognostic markers that predict disease progression, survival and also response to antifibrotic drugs. This review provides an up to date summary of the most relevant clinical trials, novel therapeutic drug targets and outlines a spectrum of potential prognostic biomarkers for IPF.

Elevated YKL40 is associated with advanced prostate cancer (PCa) and positively regulates invasion and migration of PCa cells

Chitinase 3-like 1 (CHI3L1 or YKL40) is a secreted glycoprotein highly expressed in tumours from patients with advanced stage cancers, including prostate cancer (PCa). The exact function of YKL40 is poorly understood, but it has been shown to play an important role in promoting tumour angiogenesis and metastasis. The therapeutic value and biological function of YKL40 are unknown in PCa. The objective of this study was to examine the expression and function of YKL40 in PCa. Gene expression analysis demonstrated that YKL40 was highly expressed in metastatic PCa cells when compared with less invasive and normal prostate epithelial cell lines. In addition, the expression was primarily limited to androgen receptor-positive cell lines. Evaluation of YKL40 tissue expression in PCa patients showed a progressive increase in patients with aggressive disease when compared with those with less aggressive cancers and normal controls. Treatment of LNCaP and C4-2B cells with androgens increased YKL40 expression, whereas treatment with an anti-androgen agent decreased the gene expression of YKL40 in androgen-sensitive LNCaP cells. Furthermore, knockdown of YKL40 significantly decreased invasion and migration of PCa cells, whereas overexpression rendered them more invasive and migratory, which was commensurate with an enhancement in the anchorage-independent growth of cells. To our knowledge, this study characterises the role of YKL40 for the first time in PCa. Together, these results suggest that YKL40 plays an important role in PCa progression and thus inhibition of YKL40 may be a potential therapeutic strategy for the treatment of PCa.

Expression of CHI3L1 and CHIT1 in osteoarthritic rat cartilage model. A morphological study

Osteoarthritis is a degenerative joint disease, which affects millions of people around the world. It occurs when the protective cartilage at the end of bones wears over time, leading to loss of flexibility of the joint, pain and stiffness. The cause of osteoarthritis is unknown, but its development is associated with different factors, such as metabolic, genetic, mechanical and inflammatory ones. In recent years the biological role of chitinases has been studied in relation to different inflammatory diseases and more in particular the elevated levels of human cartilage glycoprotein 39 (CHI3L1) and chitotriosidase (CHIT1) have been reported in a variety of diseases including chronic inflammation and degenerative disorders. The aim of this study was to investigate, by immunohistochemistry, the distribution of CHI3L1 and CHIT1 in osteoarthritic and normal rat articular cartilage, to discover their potential role in the development of this disease. The hypothesis was that the expression of chitinases could increase in OA disease. Immunohistochemical analysis showed that CHI3L1 and CHIT1 staining was very strong in osteoarthritic cartilage, especially in the superficial areas of the cartilage most exposed to mechanical load, while it was weak or absent in normal cartilage. These findings suggest that these two chitinases could be functionally associated with the development of osteoarthritis and could be used as markers, so in the future they could have a role in the daily clinical practice to stage the severity of the disease. However, the longer-term in vivoand in vitro studies are needed to understand the exact mechanism of these molecules, their receptors and activities on cartilage tissue.

Correlation of chitinase 3-like 1 single nucleotide polymorphisms and haplotypes with uterine cervical cancer in Taiwanese women

Background

This study aimed to investigate the relationships of chitinase 3-like 1 (CHI3L1) single nucleotide polymorphisms (SNPs) and haplotypes with the development of uterine cervical cancer in Taiwanese women. The SNPs frequencies and haplotypes were also correlated with the clinicopathologic variables of cervical cancer, cancer recurrence, and patient survival.

Methodology and Principal Findings

Ninety-nine patients with invasive cancer and 61 with pre-cancerous lesions of the uterine cervix were compared to 310 healthy control subjects. Three SNPs rs6691378 (−1371, G/A), rs10399805 (−247, G/A) and rs4950928 (−131, C/G) in the promoter region, and one SNP rs880633 (+2950, T/C) in exon 5 were analyzed by real time polymerase chain reaction and genotyping. The results showed that the mutant homozygous genotype AA of CHI3L1 SNP rs6691378 and AA of rs10399805, and haplotypes AACC and AACT increased the risk of developing pre-cancerous lesions and invasive cancer. The patients with these risk haplotypes had higher than stage I tumors, larger tumors, and vaginal invasion. In logistic regression model, they also tended to have poor survival event [p = 0.078; odds ratio (OR): 2.99, 95% confidence interval (CI): 0.89–10.08] and a higher probability of recurrence event (p = 0.081; OR: 3.07, 95% CI: 0.87–10.81). There was a significant association between the CHI3L1 risk haplotypes and probability of recurrence (p = 0.002; hazard ratio: 6.21, 95% CI: 1.90–20.41), and a marginal association between the risk haplotypes and overall survival (p = 0.051; hazard ratio: 3.76, 95% CI: 0.99–14.29) in the patients with SCC, using Cox proportional hazard model.

Conclusion

The CHI3L1 SNPs rs6691378 and rs10399805 and CHI3L1 haplotypes all correlated with the development of cervical pre-cancerous lesions and invasive cancer. The cervical cancer patients with the CHI3L1 haplotypes AACC or AACT had poor clinicopathologic characteristics and poor recurrence and survival events. These risk haplotypes were associated with higher recurrence, especially in the patients with SCC.

Increased expression of Chitinase 3-like 1 and microvessel density predicts metastasis and poor prognosis in clear cell renal cell carcinoma

Increasing evidence demonstrated that Chitinase 3-like 1 (hereafter termed CHI3L1 or YKL-40) was highly expressed and tightly associated with human tumor development and progression. However, its precise role in clear cell renal cell carcinoma (hereafter termed RCC) remains to be delineated. In the present study, we investigated the relationship between CHI3L1 expression and microvessel density (MVD), a reflection of angiogenesis, with metastasis and prognosis in patients with clear cell renal cell carcinoma (RCC). Formalin-fixed, paraffin-embedded tissue sections of clear cell RCC from 73 patients who had undergone radical nephrectomy were stained immunohistochemically with specific antibodies against CHI3L1 and CD34. CHI3L1 immunostaining was semi-quantitatively estimated based on the proportion (percentage of positive cells) and intensity. MVD was determined with CD34-stained slides. The expression pattern of CHI3L1 and MVD was compared with the clinicopathological variables. Twenty patients had either synchronous or metachronous metastases and 12 died during the follow-up. CHI3L1 intensity was significantly correlated with tumor size (P = 0.005), TNM stage (P = 0.027), M stage (P = 0.011), grade (P = 0.014), and metastasis (synchronous or metachronous; P < 0.001). The CHI3L1 proportion (P = 0.038) and MVD (P = 0.012) were significantly correlated with metastasis. MVD was correlated with CHI3L1 intensity (r = 0.376, P = 0.001) and CHI3L1 proportion (r = 0.364, P = 0.002). There was no difference in the expression of CHI3L1 and MVD between primary and metastatic sites. The survival of patients with higher CHI3L1 intensity was significantly worse than that of patients with lower CHI3L1 intensity. Multivariate analyses indicated that only M stage was an independent prognostic factor for cancer-specific survival and CHI3L1 expression was not an independent factor. Taken altogether, increased expression of CHI3L1 and MVD is associated with metastasis and a worse prognosis in clear cell RCC. CHI3L1 expression is correlated with MVD. The results suggest that CHI3L1 may be important in the progression and angiogenesis of clear cell RCC and CHI3L1 might be a novel strategy for therapy of the patients with RCC.

CHI3L1 plays a role in cancer through enhanced production of pro-inflammatory/pro-tumorigenic and angiogenic factors

Elevated serum levels of a glycoprotein known as chitinase-3-like protein 1 (CHI3L1) have been correlated with poor prognosis and shorter survival of patients with cancer and inflammatory diseases. The biological and physiological functions of CHI3L1 in cancer have not yet been completely elucidated. In this review, we describe the role of CHI3L1 in inducing pro-inflammatory/pro-tumorigenic and angiogenic factors that could promote tumor growth and metastasis.

Increased expression of YKL-40 in mild and moderate/severe persistent allergic rhinitis and its possible contribution to remodeling of nasal mucosa

BACKGROUND

Prominent expression of YKL-40 has been associated with pathological conditions characterized by tissue remodeling. We determined the expression level and distribution pattern of YKL-40 in allergic nasal mucosa and evaluated the effect of YKL-40 on the proliferation and migration of fibroblasts, the production of the mediators related to tissue remodeling, and collagen production. Additionally, the cytokine-driven regulation of YKL-40 expression was evaluated in cultured epithelial cells.

METHODS

The expression of YKL-40 in normal, mild, and moderate/severe allergic nasal mucosa was evaluated using real-time polymerase chain reaction (PCR), Western blot, and immunohistochemistry. Fibroblast migration was observed using a scratch wound method, and proliferation was determined by the MTT methods. Expression of proteoglycans, transforming growth factor (TGF) beta1, MMP2, MMP9, TIMP1, TIMP2, and collagen concentration were analyzed in fibroblasts treated with YKL-40. The expression levels of YKL-40 in cultured epithelial cells were examined after stimulation with mediators including Th2 cytokines, interferon (IFN)gamma, and TNF-alpha with real-time PCR and ELISA.

RESULTS

The expression of YKL-40 was up-regulated in allergic rhinitis and distributed in superficial epithelium, submucosal glands, and vascular endothelium, in addition to infiltrating cells. TGF-beta1, TIMP1, MMP9, and biglycan were up-regulated in fibroblasts on stimulation with YKL-40, accompanying increased proliferation and migration, and collagen production. IL-13, IFN-gamma, and TNF-alpha induced the increased production of YKL-40 in cultured epithelial cells.

CONCLUSION

YKL-40 is up-regulated in mild and moderate/severe persistent allergic rhinitis, and its expression can be regulated differentially by different cytokines, possibly contributing to the remodeling of nasal mucosa in allergic rhinitis.

Chitinase 3-like 1 suppresses injury and promotes fibroproliferative responses in Mammalian lung fibrosis

Epithelial injury, alternative macrophage accumulation, and fibroproliferation coexist in the lungs of patients with idiopathic pulmonary fibrosis (IPF). Chitinase 3-like 1 (CHI3L1) is a prototypic chitinase-like protein that has been retained over species and evolutionary time. However, the regulation of CHI3L1 in IPF and its ability to regulate injury and/or fibroproliferative repair have not been fully defined. We demonstrated that CHI3L1 levels were elevated in patients with IPF. High levels of CHI3L1 are associated with progression--as defined by lung transplantation or death--and with scavenger receptor-expressing circulating monocytes in an ambulatory IPF population. In preterminal acute exacerbations of IPF, CHI3L1 levels were reduced and associated with increased levels of apoptosis. We also demonstrated that in bleomycin-treated mice, CHI3L1 expression was acutely and transiently decreased during the injury phase and returned toward and eventually exceeded baseline levels during the fibrotic phase. In this model, CHI3L1 played a protective role in injury by ameliorating inflammation and cell death, and a profibrotic role in the repair phase by augmenting alternative macrophage activation, fibroblast proliferation, and matrix deposition. Using three-dimensional culture system of a human fibroblast cell line, we found that CHI3L1 is sufficient to induce low grade myofibroblast transformation. In combination, these studies demonstrate that CHI3L1 is stimulated in IPF, where it represents an attempt to diminish injury and induce repair. They also demonstrate that high levels of CHI3L1 are associated with disease progression in ambulatory patients and that a failure of the CHI3L1 antiapoptotic response might contribute to preterminal disease exacerbations.

Chitinase-3-like protein 1 protects skeletal muscle from TNFα-induced inflammation and insulin resistance

CHI3L1 (chitinase-3-like protein 1) is a glycoprotein consisting of 383 amino acids with a molecular mass of 40 kDa, and its serum level is elevated in inflammatory diseases. Although CHI3L1 is described as a biomarker of inflammation, the function of this protein is not completely understood. In the present study, we examined the regulation of CHI3L1 in primary human skeletal muscle cells. Moreover, we analysed potential autocrine effects of CHI3L1. We show that myotubes express CHI3L1 in a differentiation-dependent manner. Furthermore, pro-inflammatory cytokines up-regulate CHI3L1 expression (6-fold) and release (3-fold). Importantly, CHI3L1 treatment blocked TNFα (tumour necrosis factor α)-induced inflammation by inhibiting NF-κB (nuclear factor κB) activation in skeletal muscle cells. We show that this effect is mediated via PAR2 (protease-activated receptor 2). In addition, CHI3L1 treatment diminished the TNFα-induced expression and secretion of IL (interleukin)-8, MCP1 (monocyte chemoattractant protein 1) and IL-6. In addition, impaired insulin action at the level of Akt and GSK3α/β (glycogen synthase kinase 3α/β) phosphoryl-ation and insulin-stimulated glucose uptake was normalized by CHI3L1. In conclusion, the novel myokine CHI3L1, which is induced by pro-inflammatory cytokines, can counteract TNFα-mediated inflammation and insulin resistance in human skeletal muscle cells, potentially involving an auto- and/or para-crine mechanism.

Simulating tumor microenvironment: changes in protein expression in an in vitro co-culture system

BACKGROUND

The role of the microenvironment during the initiation and progression of carcinogenesis is thought to be of critical importance, both for the enhanced understanding of fundamental cancer biology as well as for improving molecular diagnostics and therapeutics. The aim of this study was to establish an in vitro model based on a co-culture of healthy human fibroblasts (HFs) and human osteosarcoma cells (MG-63s) to simulate the microenvironment including tumor and healthy cells.

METHODS

The HFs and MG-63s were in vitro co-cultured for a period of time ranging from 24 h to 7 days. Cell morphology and organization were studied using phase contrast microscopy while the expression of Human Cartilage Glycoprotein 39 (YKL-40), Vascular Endothelial Growth Factor (VEGF) and Matrix Metalloprotease 1 (MMP1) was investigated by Real Time PCR and Western Blotting.

RESULTS

The results showed a characteristic disposition of tumor and healthy co-cultured cells in columns which are not visible in tumor and healthy cells grown singularly. The expression of YKL-40, VEGF and MMP1 significantly changed in co-cultured cells compared to HFs and MG-63s separately cultured.

CONCLUSIONS

We concluded that the tumor microenvironment has an influence on the protein expression of the healthy surrounding tissues and the process of tumorigenicity.

Antibody directed against human YKL-40 increases tumor volume in a human melanoma xenograft model in scid mice

Induced overexpression of the secretory protein YKL-40 promotes tumor growth in xenograft experiments. We investigated if targeting YKL-40 with a monoclonal antibody could inhibit tumor growth. YKL-40 expressing human melanoma cells (LOX) were injected subcutenously in Balb/c scid mice. Animals were treated with intraperitoneal injections of anti-YKL-40, isoptype control or PBS. Non-YKL-40 expressing human pancreatic carcinoma cell line PaCa 5061 served as additional control. MR imaging was used for evaluation of tumor growth. Two days after the first injections of anti-YKL-40, tumor volume had increased significantly compared with controls, whereas no effects were observed for control tumors from PaCa 5061 cells lacking YKL-40 expression. After 18 days, mean tumor size of the mice receiving repeated anti-YKL-40 injections was 1.82 g, >4 times higher than mean tumor size of the controls (0.42 g). The effect of anti-YKL-40 on the increase of tumor volume started within hours after injection and was dose dependent. Intratumoral hemorrhage was observed in the treated animals. The strong effect on tumor size indicates important roles for YKL-40 in melanoma growth and argues for a careful evaluation of antibody therapy directed against YKL-40.

Determination of chitinases family during osteoclastogenesis

Mammalian chitinases consisting of CHIA, CHIT1, CHI3L1, CHI3L2 and CHID1 exert important biological roles in the monocyte lineage and chronic inflammatory diseases. Pathological bone resorption is a cause of significant morbidity in diseases affecting the skeleton such as rheumatoid arthritis, osteoporosis, periodontitis and cancer metastasis. The biologic role of chitinases in bone resorption is poorly understood. In this study, we evaluated the expression of the chitinases family during osteoclast differentiation. The expression of CHIA, CHI3L2 and CHID1 resulted unchanged during osteoclast differentiation, whereas CHIT1 and CHI3L1 increased significantly. We also observed that CHIT1 and CHI3L1 are involved in osteoclast function. Indeed, silencing CHIT1 and CHI3L1 with siRNA resulted in a significant decrease in bone resorption activity. In addition, transfection with CHIT1 or CHI3L1 siRNA and co-transfection with both decreased the levels of the pro-differentiative marker MMP9. Overall, these discoveries reveal a novel and crucial role for both CHIT1 and CHI3L1 in promoting bone resorption and identifying new potential candidate markers for therapeutic targeting.

Chitinase 3 like 1 is associated with tumor angiogenesis in cervical cancer

Elevated serum levels of a secreted glycoprotein chitinase 3 like 1 (CHI3L1) are associated with poor prognosis and short survival time of patients with cervical cancer (CxCa). Our previous microarray data showed the increased expression of CHI3L1 in invasive CxCa compared to normal tissue, implicating a potential role of CHI3L1 in CxCa. To establish the pathological role of CHI3L1 in the development of CxCa, this study focused on its expression in CxCa and angiogenic impacts in tumor vessel formation. CHI3L1 activated angiogenesis by promoting endothelial cell migration and tube formation in vitro but failed to protect CxCa cell lines, CaSki and HeLa against apoptosis induced by γ-irradiation. In addition, the capability of CHI3L1 to induce proliferation and migration of CaSki and HeLa cells was cell type specific. In an analysis of 103 specimens from CxCa patients, increased expression levels of CHI3L1 mRNA and protein in invasive CxCa were 4-fold (P<0.05) and 2-fold (P<0.01), respectively, stronger than those in normal subjects. The immunostaining of CHI3L1 was positively correlated with VEGF expression (P=0.0019) and microvessel density (P=0.0110). Moreover, CHI3L1 expression was also positively associated with cancer metastasis (P=0.011). The data suggest the crucial role of CHI3L1 by promoting angiogenesis, which may contribute to the development and progression of CxCa. The findings help establish CHI3L1 as a prognostic biomarker and therapeutic target for CxCa patients.

The Effect of Recombinant Human Interleukin-6 on Osteogenic Differentiation and YKL-40 Expression in Human, Bone Marrow-Derived Mesenchymal Stem Cells

Human mesenchymal stem cells are an attractive cell source for tissue engineering and regenerative medicine applications, especially because of their differentiation potential toward the mesenchymal lineage. Furthermore, this cell type participates in the regeneration of tissue damage and plays an important role in immunity. Similarly, chitinase-like proteins have been proposed to aid in tissue remodeling, inflammation, and differentiation processes. The chitinase-like protein YKL-40 in particular is indicated in preventing damage to the extracellular matrix in response to proinflammatory cytokines, even though its biological function remains speculative. Finally, interleukin (IL)-6, a pleiotropic acute phase protein, participates in the regulation of bone turnover and immunoregulation. The physiological role of IL-6 in bone homeostasis is complex, exerting different effects on osteoblasts and osteoclasts depending on their differentiation stage. The aim of this study was to determine the effect of recombinant human IL-6 (5 ng/mL) on YKL-40 expression and osteogenic differentiation of human mesenchymal stem cells. Recombinant human IL-6 induced a donor-dependent change in mineralization and significantly promoted YKL-40 protein secretion. However, YKL-40 gene expression remained unaffected, and no statistically significant differences in the expression of osteogenic marker genes could be observed.

Potential association between TLR4 and chitinase 3-like 1 (CHI3L1/YKL-40) signaling on colonic epithelial cells in inflammatory bowel disease and colitis-associated cancer

Inflammatory bowel disease (IBD) is a group of inflammatory disorders in the small and large intestines. Several studies have proved that persistent and disregulated host/microbial interactions are required for the development of IBD. It is well known that chronic IBD is strongly associated with an increased risk of developing colorectal cancer by 0.5-1% annually, 8-10 years after the initial diagnosis. To detect the tiny dysplasia or early stage of cancer in chronic IBD patients, a tremendous amount of effort is currently directed for improving colonoscopic technology and noninvasive serological marker development. However, there is only a limited amount of data available to understand the exact mechanism of how long term chronic colitis is connected to the development of colorectal tumors. Recently, our group has identified significantly increased expression of chitinase 3-like 1 (CHI3L1) molecule in non-dysplastic mucosa from patients with IBD and remote dysplasia/cancer, compared to patients with IBD without dysplasia or healthy controls. CHI3L1 seems to contribute to the proliferation, migration, and neoplastic progression of colonic epithelial cells (CECs) under inflammatory conditions. Furthermore, the TLR4-mediated intracellular signaling cascade is likely to interact with CHI3L1 signaling in CECs. In this review article, we have concisely summarized the cellular and molecular mechanisms underlining the development of IBD and colitis-associated cancer, with particular focus on the TLR4- and CHI3L1-signaling pathways in CECs.

Cells from the skin of patients with systemic sclerosis secrete chitinase 3-like protein 1

Background

The chitinase-like protein, Chi3L1, is associated with increased fibrotic activity as well as inflammatory processes. The capacity of skin cells from systemic sclerosis (SSc) patients to produce Chi3L1, and the stimulation of its synthesis by cytokines or growth factors known to be associated with SSc, was investigated.

Methods

Cells were isolated from forearm and/or abdomen skin biopsies taken from SSc patients and normal individuals and stimulated with cytokines and growth factors to assess Chi3L1 expression. Chi3L1-expressing cells were characterized by immunohistochemical staining.

Results

Chi3L1 was not secreted by skin cells from normal individuals nor was its synthesis induced by any of the cytokines or growth factors investigated. In contrast, Chi3L1 secretion was induced by OSM or IL-1 in cells from all forearm biopsies of SSc patients, and endogenous secretion in the absence of cytokines was detected in several specimens. Patients with Chi3L1-producing cells at both the arm and abdomen had a disease duration of less than 3 years. Endogenous Chi3L1 production was not a property of the major fibroblast population nor of myofibroblasts, but rather was related to the presence of stem-like cells not present in normal skin. Other cells, however, contributed to the upregulation of Chi3L1 by OSM.

Conclusions

The emergence of cells primed to respond to OSM with increased Chi3L1 production appears to be associated with pathological processes active in SSc.

General significance

The presence of progenitor cells expressing the chilectin Chi3L1 in SSc skin appears to play a role in the initiation of the disease process.

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Cells isolated from the skin of scleroderma patients secrete Chi3L1.

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Chi3L1 production is stimulated by oncostatin M or interleukin 1.

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Patients with Chi3L1 producing cells have disease duration of < 3 years.

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Chi3L1 production is a property of stem-like cells not present in normal skin.

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Other cells contribute to Chi3L1 upregulation by oncostatin M.

Efficacy and safety of mavrilimumab in subjects with rheumatoid arthritis

OBJECTIVES

Mavrilimumab, a human monoclonal antibody targeting the alpha subunit of the granulocyte-macrophage colony-stimulating factor receptor, was evaluated in a phase 2 randomised, double-blind, placebo-controlled study to investigate efficacy and safety in subjects with rheumatoid arthritis (RA).

METHODS

Subcutaneous mavrilimumab (10 mg, 30 mg, 50 mg, or 100 mg) or placebo was administered every other week for 12 weeks in subjects on stable background methotrexate therapy. The primary endpoint was the proportion of subjects achieving a ≥1.2 decrease from baseline in Disease Activity Score (DAS28-CRP) at week 12.

RESULTS

55.7% of mavrilimumab-treated subjects met the primary endpoint versus 34.7% placebo (p=0.003) at week 12; for the 10 mg, 30 mg, 50 mg, and 100 mg groups, responses were 41.0% (p=0.543), 61.0% (p=0.011), 53.8% (p=0.071), and 66.7% (p=0.001) respectively. Response rate differences from placebo were observed at week 2 and increased throughout the treatment period. The 100 mg dose demonstrated a significant effect versus placebo on DAS28-CRP<2.6 (23.1% vs 6.7%, p=0.016), all categories of the American College of Rheumatology (ACR) criteria (ACR20: 69.2% vs 40.0%, p=0.005; ACR50: 30.8% vs 12.0%, p=0.021; ACR70: 17.9% vs 4.0%, p=0.030), and the Health Assessment Questionnaire Disability Index (-0.48 vs -0.25, p=0.005). A biomarker-based disease activity score showed a dose-dependent decrease at week 12, indicating suppression of disease-related biological pathways. Adverse events were generally mild or moderate in intensity. No significant hypersensitivity reactions, serious or opportunistic infections, or changes in pulmonary parameters were observed.

CONCLUSIONS

Mavrilimumab induced rapid clinically significant responses in RA subjects, suggesting that inhibiting the mononuclear phagocyte pathway may provide a novel therapeutic approach for RA.

YKL-40 expression could be a poor prognostic marker in the breast cancer tissue

YKL-40 is a glycoprotein involved in cellular growth, migration, and the inflammatory process. Elevation in serum levels of YKL-40 has been associated with worse prognosis in various cancers, including breast cancer. Given that the clinical significance of YKL-40 expression in breast cancer tissue is unclear, we aimed to determine the prognostic value of YKL-40 expression in breast cancer tissue using immunohistochemistry. We performed tissue microarray (TMA) analysis of 425 breast cancer tissues collected during operation. Immunohistochemical staining was performed to measure expression of YKL-40 and several breast cancer biomarkers, such as aldehyde dehyadrogenase1, TGF-beta, and Gli-1 as well as hormonal receptor and Her-2/neu status. Statistical analysis of the relationship of YKL-40 expression with clinicopathological characteristics was performed for 390 TMA samples. YKL-40 was expressed to varying degrees in 84.9% of breast cancer tissues. YKL-40 expression was correlated with estrogen receptor and progesterone receptor negativity and was positively correlated with TGF-beta and Gli-1 expression. Strong YKL-40 expression was associated with a larger proportion of Her-2/neu-enriched and basal-like tumors. The results of this study demonstrate that YKL-40 expression in breast cancer tissues is associated with hormone receptor negativity and Her-2/neu-enriched molecular subtypes of breast cancer, and therefore could be considered a poor prognostic predictor.

Diagnostic and Prognostic Impact of Circulating YKL-40, IL-6, and CA 19.9 in Patients with Pancreatic Cancer

Purpose

We tested the hypothesis that high plasma YKL-40 and IL-6 associate with pancreatic cancer and short overall survival.

Patients and Methods

In all, 559 patients with pancreatic cancer from prospective biomarker studies from Denmark (n = 448) and Germany (n = 111) were studied. Plasma YKL-40 and IL-6 were determined by ELISAs and serum CA 19.9 by chemiluminescent immunometric assay.

Results

Odds ratios (ORs) for prediction of pancreatic cancer were significant for all biomarkers, with CA 19.9 having the highest AUC (CA 19.9: OR = 2.28, 95% CI 1.97 to 2.68, p<0.0001, AUC = 0.94; YKL-40: OR = 4.50, 3.99 to 5.08, p<0.0001, AUC = 0.87; IL-6: OR = 3.68, 3.08 to 4.44, p<0.0001, AUC = 0.87). Multivariate Cox analysis (YKL-40, IL-6, CA 19.9, age, stage, gender) in patients operated on showed that high preoperative IL-6 and CA 19.9 (dichotomized according to normal values) were independently associated with short overall survival (CA 19.9: HR = 2.51, 1.22–5.15, p = 0.013; IL-6: HR = 2.03, 1.11 to 3.70, p = 0.021). Multivariate Cox analysis of non-operable patients (Stage IIB-IV) showed that high pre-treatment levels of each biomarker were independently associated with short overall survival (YKL-40: HR = 1.30, 1.03 to 1.64, p = 0.029; IL-6: HR = 1.71, 1.33 to 2.20, p<0.0001; CA 19.9: HR = 1.54, 1.06 to 2.24, p = 0.022). Patients with preoperative elevation of both IL-6 and CA 19.9 had shorter overall survival (p<0.005) compared to patients with normal levels of both biomarkers (45% vs. 92% alive after 12 months).

Conclusions

Plasma YKL-40 and IL-6 had less diagnostic impact than CA 19.9. Combination of pretreatment YKL-40, IL-6, and CA 19.9 may have clinical value to identify pancreatic cancer patients with the poorest prognosis.

The expression of chitinase 3-like 1: a novel prognostic predictor for hepatocellular carcinoma

OBJECTIVES

Chitinase 3-like 1 (CHI3L1) is associated with poor prognosis of various human cancers. However, the clinical and prognostic significance of CHI3L1 in hepatocellular carcinoma (HCC) is largely unknown. The aim of the present study is to investigate the expression of CHI3L1 in human HCC cell lines, clinical HCC specimens and its association with expressions of phosphorylated-Akt (p-Akt), E-cadherin and prognostic significance.

METHODS

The protein level of CHI3L1 in HCC cell lines was evaluated by western blot. The mRNA and protein levels of CHI3L1 in 19 self-paired HCC specimens were assessed by RT-PCR and western blot assays. The clinical and prognostic significance of CHI3L1 in 70 cases of HCC patients was determined by immunohistochemistry. In addition, expressions of p-Akt and E-cadherin were also assessed.

RESULTS

The protein level of CHI3L1 paralleled with increased malignant potential of HCC cell lines (P < 0.05). The mRNA and protein levels of CHI3L1 in HCC tissues were up-regulated compared with those in adjacent peritumoral tissues and further increased in tumors with metastasis (P < 0.05). Clinicopathological analysis showed that positive CHI3L1 expression was significantly associated with larger tumor size, capsular invasion, advanced TNM stages and status of metastasis (P = 0.035, 0.003, 0.023 and 0.003, respectively). Furthermore, CHI3L1 expression was positively correlated with high level of p-Akt (r = 0.293, P = 0.014), but inversely correlated with expression of E-cadherin (r = -0.267, P = 0.026). Additionally, Kaplan-Meier survival analysis showed that HCC patients with positive CHI3L1 expression had a worse overall survival and disease-free survival compared with those with negative CHI3L1 expression (P < 0.001, respectively). Multivariate analysis identified CHI3L1 as an independent prognostic predictor for overall survival and disease-free survival of HCC patients (P = 0.044 and 0.031, respectively).

CONCLUSIONS

CHI3L1 plays an essential role in HCC malignancies and may be served as a valuable prognostic biomarker for HCC patients.

YKL-40 acts as an angiogenic factor to promote tumor angiogenesis

A secreted glycoprotein YKL-40 also named chitinase-3-like-1 is normally expressed by multiple cell types such as macrophages, chondrocytes, and vascular smooth muscle cells. However, a prominently high level of YKL-40 was found in a wide spectrum of human diseases including cancers and chronic inflammatory diseases where it was strongly expressed by cancerous cells and infiltrating macrophages. Here, we summarized recent important findings of YKL-40 derived from cancerous cells and smooth muscle cells during tumor angiogenesis and development. YKL-40 is a potent angiogenic factor capable of stimulating tumor vascularization mediated by endothelial cells and maintaining vascular integrity supported by smooth muscle cells. In addition, YKL-40 induces FAK-MAPK signaling and up-regulates VEGF receptor 2 in endothelial cells; but a neutralizing antibody (mAY) against YKL-40 inhibits its angiogenic activity. While YKL-40 is essential for angiogenesis, little is known about its functional role in tumor-associated macrophage (TAM)-mediated tumor development. Therefore, significant efforts are urgently needed to identify pathophysiological function of YKL-40 in the dynamic interaction between tumor cells and TAMs in the tumor microenvironment, which may offer substantial mechanistic insights into tumor angiogenesis and metastasis, and also point to a therapeutic target for treatment of cancers and other diseases.

Expression of the chitinase family glycoprotein YKL-40 in undifferentiated, differentiated and trans-differentiated mesenchymal stem cells

The glycoprotein YKL-40 (CHI3L1) is a secreted chitinase family protein that induces angiogenesis, cell survival, and cell proliferation, and plays roles in tissue remodeling and immune regulation. It is expressed primarily in cells of mesenchymal origin, is overexpressed in numerous aggressive carcinomas and sarcomas, but is rarely expressed in normal ectodermal tissues. Bone marrow-derived mesenchymal stem cells (MSCs) can be induced to differentiate into various mesenchymal tissues and trans-differentiate into some non-mesenchymal cell types. Since YKL-40 has been used as a mesenchymal marker, we followed YKL-40 expression as undifferentiated MSCs were induced to differentiate into bone, cartilage, and neural phenotypes. Undifferentiated MSCs contain significant levels of YKL-40 mRNA but do not synthesize detectable levels of YKL-40 protein. MSCs induced to differentiate into chondrocytes and osteocytes soon began to express and secrete YKL-40 protein, as do ex vivo cultured chondrocytes and primary osteocytes. In contrast, MSCs induced to trans-differentiate into neurons did not synthesize YKL-40 protein, consistent with the general absence of YKL-40 protein in normal CNS parenchyma. However, these trans-differentiated neurons retained significant levels of YKL-40 mRNA, suggesting the mechanisms which prevented YKL-40 translation in undifferentiated MSCs remained in place, and that these trans-differentiated neurons differ in at least this way from neurons derived from neuronal stem cells. Utilization of a differentiation protocol containing β-mercaptoethanol resulted in cells that expressed significant amounts of intracellular YKL-40 protein that was not secreted, which is not seen in normal cells. Thus the synthesis of YKL-40 protein is a marker for MSC differentiation into mature mesenchymal phenotypes, and the presence of untranslated YKL-40 mRNA in non-mesenchymal cells derived from MSCs reflects differences between differentiated and trans-differentiated phenotypes.

Partially acetylated chitooligosaccharides bind to YKL-40 and stimulate growth of human osteoarthritic chondrocytes

Recent evidences indicating that cellular kinase signaling cascades are triggered by oligomers of N-acetylglucosamine (ChOS) and that condrocytes of human osteoarthritic cartilage secrete the inflammation associated chitolectin YKL-40, prompted us to study the binding affinity of partially acetylated ChOS to YKL-40 and their effect on primary chondrocytes in culture. Extensive chitinase digestion and filtration of partially deacetylated chitin yielded a mixture of ChOS (Oligomin™) and further ultrafiltration produced T-ChOS™, with substantially smaller fraction of the smallest sugars. YKL-40 binding affinity was determined for the different sized homologues, revealing micromolar affinities of the larger homologues to YKL-40. The response of osteoarthritic chondrocytes to Oligomin™ and T-ChOS™ was determined, revealing 2- to 3-fold increases in cell number. About 500 μg/ml was needed for Oligomin™ and around five times lower concentration for T-ChOS™, higher concentrations abolished this effect for both products. Addition of chitotriose inhibited cellular responses mediated by larger oligosaccharides. These results, and the fact that the partially acetylated T-ChOS™ homologues should resist hydrolysis, point towards a new therapeutic concept for treating inflammatory joint diseases.

YKL-40 induces IL-8 expression from bronchial epithelium via MAPK (JNK and ERK) and NF-κB pathways, causing bronchial smooth muscle proliferation and migration

Recently, the serum levels of YKL-40, a chitinase-like glycoprotein, have been shown to be significantly elevated in asthmatics and are associated with asthma severity. Although these studies raise the possibility that YKL-40 may influence asthma, the mechanisms remain unknown. This study firstly investigated the mechanisms involved in YKL-40-mediated inflammation in human bronchial epithelial cells (HBECs) and analyzed the soluble factors secreted by bronchial epithelial cells exposed to YKL-40 that were responsible for increasing proliferation and migration of primary normal human bronchial smooth muscle cells (BSMCs). YKL-40-induced inflammation was assayed in two HBECs (BEAS-2B cell line and primary HBECs). In addition, we treated BEAS-2B cells and HBECs with YKL-40 and added the conditioned culture media to BSMCs. The proliferation and migration of BSMCs were determined by premixed WST-1 cell proliferation reagent (Clontech Laboratories) and QCM chemotaxis migration assay (Millipore), respectively. Bronchial epithelial cells treated with YKL-40 resulted in a significant increase of IL-8 production, which was dependent on MAPK (JNK and ERK) and NF-κB pathways activation. YKL-40-induced IL-8 was found to further stimulate proliferation and migration of BSMCs, and the effects were inhibited after neutralizing IL-8. Through investigating the interaction of airway epithelium and smooth muscle, our findings implicate that YKL-40 may be involved in the inflammation of asthma by induction of IL-8 from epithelium, subsequently contributing to BSMC proliferation and migration. Moreover, inhibition of IL-8 signaling is a potential therapeutic target for YKL-40-induced inflammation and remodeling of asthma.

Increased levels of YKL-40 and interleukin 6 in patients with chronic pancreatitis and secondary diabetes

OBJECTIVES

Circulating levels of YKL-40 and interleukin 6 (IL-6) are elevated in patients with type 2 diabetes. We aimed to evaluate YKL-40 levels in patients with chronic pancreatitis (CP) with and without secondary diabetes mellitus (DM) to investigate whether elevated plasma YKL-40 could play a primary role in the pathogenesis of type 2 diabetes or rather represent a consequence of the diabetic state.

METHODS

Plasma levels of YKL-40 and IL-6 were measured during an oral glucose tolerance test in 8 patients with CP and secondary DM, 8 patients with CP and normal glucose tolerance (NGT), and 8 healthy control subjects (CTRLs).

RESULTS

Plasma YKL-40 and IL-6 were significantly higher in patients with CP and secondary DM (YKL-40, mean [95% confidence interval], 113 [60-215 ng/mL]; IL-6, 4.6 [2.3-9.1 pg/mL]) compared to patients with CP and NGT (YKL-40, 42 [28-63 ng/mL]; IL-6, 1.4 [0.8-2.4 pg/mL]) and healthy control subjects (YKL-40, 46 [31-69 ng/mL]; IL-6, 1.4 [0.8-2.4 pg/mL]).

CONCLUSIONS

Patients with CP and secondary DM have elevated levels of YKL-40 and IL-6 compared to CP patients with NGT and healthy subjects, suggesting that YKL-40 is not a primary mediator of DM but a consequence of the diabetic state.

A phase 1 open-label trial shows that smad7 antisense oligonucleotide (GED0301) does not increase the risk of small bowel strictures in Crohn’s disease

BACKGROUND

In Crohn's disease (CD), knockdown of Smad7, an inhibitor of Transforming Growth Factor (TGF)-β1 activity, with a specific antisense oligonucleotide (GED0301) seems to be safe and tolerable and associates with TGF-β1-mediated suppression of inflammatory pathways.

AIM

Since TGF-β1 has pro-fibrogenic effects in many organs, we evaluated whether GED0301 treatment associates with the formation of small bowel strictures.

METHODS

Fifteen patients with active, inflammatory CD, receiving oral GED0301 once daily for 7 days, were monitored for the formation of small bowel strictures by Small Intestine Contrast Ultrasonography (SICUS). Serum basic fibroblast growth factor (bFGF) and human chitinase 3-like 1 (also known as YKL-40), two markers of CD-related intestinal strictures, and matrix metalloproteinases (MMP) and tissue inhibitor 1 of MMPs (TIMP1) were analysed at day 0 and day 180 by ELISA. Crohn's disease activity index (CDAI) changes were also monitored.

RESULTS

Fourteen patients completed the 6-month study; the remaining underwent intestinal resection for a severe relapse not responsive to medical treatment. No patient developed small bowel stricture and none experienced obstructive symptoms during the study period. GED0301 treatment induced no significant change in the circulating levels of bFGF, YKL-40, MMPs and TIMP1. Seven of 12 patients who reached clinical remission following GED0301 treatment maintained a CDAI < 150 at day 180.

CONCLUSION

Short-term treatment of patients with Crohn's disease using GED0301 is not associated with the development of small bowel stricture, thus reinforcing the concept that this drug is safe at least at early time points.

High levels of phosphorylated MAP kinase are associated with poor survival among patients with glioblastoma during the temozolomide era

We investigated whether high levels of activated mitogen-activated protein kinase (p-MAPK) were associated with poor survival among patients with newly diagnosed glioblastoma during the temozolomide era. Nuclear p-MAPK expression of 108 patients with GBM was quantified and categorized in the following levels: low (0%-10%), medium (11%-40%), and high (41%-100%). Independent predictors of overall survival were determined using a multivariate Cox proportional hazards model. Our study included 108 patients with newly diagnosed GBM. Median age was 65 years, and 74% had high Karnofsky performance status (KPS ≥ 80). Median overall survival among all patients was 19.5 months. Activated MAPK expression levels of <10%, 11%-40%, and ≥ 41% were observed in 33 (30.6%), 37 (34.3%), and 38 (35.2%) patients, respectively. Median survival for low, medium, and high p-MAPK expression was 32.4, 18.2, and 12.5 months, respectively. Multivariate analysis showed 2.4-times hazard of death among patients with intermediate p-MAPK than low p-MAPK expression (hazard ratio [HR], 2.4; P = .02); high-expression patients were 3.9 times more likely to die, compared with patients with low p-MAPK (HR, 3.9; P = .007). Patients aged ≥ 65 years (HR, 2.8; P = .002) with KPS < 80 (HR, 3.1; P = .0003) and biopsy or partial resection (HR, 1.9; P = .02) had higher hazard of death. MGMT and PTEN expression were not associated with survival differences. This study provides quantitative means of evaluating p-MAPK in patients with GBM. It confirms the significant and independent prognostic relevance of p-MAPK in predicting survival of patients with GBM treated in the temozolomide era and highlights the need for therapies targeting the p-MAPK oncogenic pathway.

Human YKL-39 is a pseudo-chitinase with retained chitooligosaccharide-binding properties

The chitinase-like proteins YKL-39 (chitinase 3-like-2) and YKL-40 (chitinase 3-like-1) are highly expressed in a number of human cells independent of their origin (mesenchymal, epithelial or haemapoietic). Elevated serum levels of YKL-40 have been associated with a negative outcome in a number of diseases ranging from cancer to inflammation and asthma. YKL-39 expression has been associated with osteoarthritis. However, despite the reported association with disease, the physiological or pathological role of these proteins is still very poorly understood. Although YKL-39 is homologous to the two family 18 chitinases in the human genome, it has been reported to lack any chitinase activity. In the present study, we show that human YKL-39 possesses a chitinase-like fold, but lacks key active-site residues required for catalysis. A glycan screen identified oligomers of N-acetylglucosamine as preferred binding partners. YKL-39 binds chitooligosaccharides and a newly synthesized derivative of the bisdionin chitinase-inhibitor class with micromolar affinity, through a number of conserved tryptophan residues. Strikingly, the chitinase activity of YKL-39 was recovered by reverting two non-conservative substitutions in the active site to those found in the active enzymes, suggesting that YKL-39 is a pseudo-chitinase with retention of chitinase-like ligand-binding properties.

The Association between genetic variations of CHI3L1, levels of the encoded glycoprotein YKL-40 and the lipid profile in a Danish population

Background

The inflammatory biomarker YKL-40 seems to play a role in atherosclerosis and is elevated in patients with obesity, cardiovascular disease and type 2 diabetes. Single nucleotide polymorphisms (SNPs) of the YKL-40 encoding gene, CHI3L1, are associated with inter-individual YKL-40 levels. One study has described an association between a promoter polymorphism of CHI3L1 and levels of low density lipoprotein. The objective of this study was to evaluate the influence of YKL-40 on lipid parameters by determining the association between polymorphisms of CHI3L1, serum YKL-40 and levels of the differentiated lipid profile in a Danish general population.

Methodology/Principle Findings

12 SNPs of CHI3L1 were genotyped, and serum YKL-40 and parameters of the lipid profile were measured in 2,656 Danes. Lipid profile and genotypes were available in another Danish population (n = 6,784) for replication. Cholesterol and triglyceride levels increased with increasing YKL-40 quartile (both p<0.0001), and YKL-40 correlated with triglyceride levels (β = 0.15, p<0.0001). Low density lipoprotein levels increased slightly from the 1^st to the 3^rd quartile (p = 0.006). The highest YKL-40 quartile was associated with a greater risk of hypercholesterolemia compared to the lowest YKL-40 quartile (odds ratio 1.36, p = 0.009). Minor homozygosity of rs12123883 was associated with higher triglyceride levels (p = 0.022) and a higher prevalence of low high density lipoprotein (p = 0.012), but these associations could not be confirmed in the replication population.

Conclusions/Significance

Serum YKL-40 correlates with triglyceride levels in a representative group of the general Danish population. No consistent associations between SNPs of CHI3L1 and lipid levels could be documented.

Chitosan and Chitin Hexamers affect expansion and differentiation of mesenchymal stem cells differently

Chitooligosaccharides are of interest as potential drugs due to their bioactivity and water solubility. We compared the effect of acetylated and deacetylated chitooligomers (Hexamers) on short-term expansion (7 days) and osteogenic differentiation of bone-marrow derived, human mesenchymal stem cells in terms of gene expression, cytokine secretion and quality of osteogenic differentiation. We show that chitooligomers affect hMSC gene expression and cytokine secretion, but not mineralization. The effect of chitooligomers was shown to be dependent on the acetylation degree, with significantly stronger effects when cells are stimulated with chitin-derived Hexamers (N-Acetyl Chitohexaose) than with Chitosan Hexamers (Chitohexaose).

Review: molecular pathology in adult high-grade gliomas: from molecular diagnostics to target therapies

The classification of malignant gliomas is moving from a morphology-based guide to a system built on molecular criteria. The development of a genomic landscape for gliomas and a better understanding of its functional consequences have led to the development of internally consistent molecular classifiers. However, development of a biologically insightful classification to guide therapy is still a work in progress. Response to targeted treatments is based not only on the presence of drugable targets, but rather on the molecular circuitry of the cells. Further, tumours are heterogeneous and change and adapt in response to drugs. Therefore, the challenge of developing molecular classifiers that provide meaningful ways to stratify patients for therapy remains a major challenge for the field. In this review, we examine the potential role of MGMT methylation, IDH1/2 mutations, 1p/19q deletions, aberrant epidermal growth factor receptor and PI3K pathways, abnormal p53/Rb pathways, cancer stem-cell markers and microRNAs as prognostic and predictive molecular markers in the setting of adult high-grade gliomas and we outline the clinically relevant subtypes of glioblastoma with genomic, transcriptomic and proteomic integrated analyses. Furthermore, we describe how these advances, especially in epidermal growth factor receptor/PI3K/mTOR signalling pathway, affect our approaches towards targeted therapy, raising new challenges and identifying new leads.

Involvement of the MAPK and PI3K pathways in chitinase 3-like 1-regulated hyperoxia-induced airway epithelial cell death

BACKGROUND

Exposure to 100% oxygen causes hyperoxic acute lung injury characterized by cell death and injury of alveolar epithelial cells. Recently, the role of chitinase 3-like 1 (CHI3L1), a member of the glycosyl hydrolase 18 family that lacks chitinase activity, in oxidative stress was demonstrated in murine models. High levels of serum CHI3L1 have been associated with various diseases of the lung, such as asthma, chronic obstructive pulmonary disease, and cancer. However, the role of CHI3L1 in human airway epithelial cells undergoing oxidative stress remains unknown. In addition, the signaling pathways associated with CHI3L1 in this process are poorly understood.

PURPOSE

In this study, we demonstrate the role of CHI3L1, along with the MAPK and PI3K signaling pathways, in hyperoxia-exposed airway epithelial cells.

METHOD

The human airway epithelial cell line, BEAS-2B, was exposed to >95% oxygen (hyperoxia) for up to 72h. Hyperoxia-induced cell death was determined by assessing cell viability, Annexin-V FITC staining, caspase-3 and -7 expression, and electron microscopy. CHI3L1 knockdown and overexpression studies were conducted in BEAS-2B cells to examine the role of CHI3L1 in hyperoxia-induced apoptosis. Activation of the MAPK and PI3K pathways was also investigated to determine the role of these signaling cascades in this process.

RESULTS

Hyperoxia exposure increased CHI3L1 expression and apoptosis in a time-dependent manner. CHI3L1 knockdown protected cells from hyperoxia-induced apoptosis. In contrast, CHI3L1 overexpression promoted cell death after hyperoxia exposure. Finally, phosphorylation of ERK1/2, p38, and Akt were affected by CHI3L1 knockdown.

CONCLUSION

This study indicates that CHI3L1 is involved in hyperoxia-induced cell death, suggesting that CHI3L1 may be one of several cell death regulators influencing the MAPK and PI3K pathways during oxidative stress in human airway epithelial cells.

YKL-40 levels and atrial fibrillation in the general population

BACKGROUND

Atrial fibrillation is associated with inflammation. In contrast to inflammatory markers like C-reactive protein (CRP) and fibrinogen produced in the liver, YKL-40 is produced at the site of inflammation including in the myocardium. We hypothesized that elevated plasma YKL-40 levels associate with increased risk of atrial fibrillation.

METHOD AND RESULTS

We measured plasma YKL-40 in 8731 participants from the prospective Copenhagen City Heart Study including 896 individuals who developed atrial fibrillation during up to 18 years of follow-up. Additionally, we measured YKL-40 in 6621 individuals from the cross-sectional Copenhagen General Population Study including 337 cases with atrial fibrillation. A YKL-40 level >95% percentile (>204 μg/L) versus <25% percentile (<36 μg/L) associated prospectively with a 2.10-fold (95%CI:1.43-3.09) increased risk of atrial fibrillation. Hazard ratios attenuated slightly after multifactorial adjustment to 2.01 (1.35-2.98), and further after additional adjustment for heart failure to 1.89 (1.27-2.80), for plasma CRP to 1.79 (1.20-2.67), and for fibrinogen levels to 1.89 (1.27-2.81). Adjusting multifactorially including both heart failure, CRP, and fibrinogen attenuated the risk of atrial fibrillation to 1.79 (1.20-2.67). These findings were supported in the cross-sectional study with an odds ratio of 2.73 (1.46-5.11) for a YKL-40 level >95% percentile versus <25% percentile, attenuating to an odds ratio of 2.13 (1.09-4.18) when adjusting multifactorially including heart failure, CRP, and fibrinogen.

CONCLUSIONS

Elevated plasma YKL-40 levels robustly associated with increased risk of atrial fibrillation originating from hospital admissions or visits to the emergency department, independent of heart failure, and CRP and fibrinogen levels. These findings need to be confirmed in other independent studies.

A promoter variant in the chitinase 3-like 1 gene is associated with serum YKL-40 level and personality trait

The chitinase 3-like 1 (CHI3L1) gene, a cellular survival factor against several environmental and psychosocial stresses, has been sown to be more highly expressed in the hippocampus and prefrontal cortex of patients with schizophrenia than unaffected individuals. We recently reported a significant association between schizophrenia and SNP rs4950928, which is located in the promoter region of the CHI3L1 gene, in a Japanese population. The G-allele at this SNP in the gene has been associated with higher transcriptional activity in a luciferase reporter assay and with higher mRNA levels in the peripheral blood cells of patients with schizophrenia. We investigated the impact of the CHI3L1 polymorphism rs4950928 on serum YKL-40 levels, the protein product of CHI3L1. We found that individuals with the G-allele, who were more prevalent among patients with schizophrenia, had significantly higher serum YKL-40 levels (p=0.043). Personality traits are considered to be an important aspect of schizophrenia primarily because they may influence symptoms and social functioning. Personality trait analyses using the temperament and character inventory (TCI) indicated that schizophrenic patients have a unique personality profile that appears to be present across cultures. We hypothesized that higher serum YKL-40 levels are associated with personality trait in patients with schizophrenia. Thus, we next examined the impact of the risk CHI3L1 polymorphism on personality traits using the TCI. We found that individuals with the G-allele had significantly higher self-transcendence scores (p=0.0054). These findings suggest possible associations between the SNP in the CHI3L1 gene, the risk for schizophrenia, and higher serum YKL-40 levels and personality traits in a Japanese population.

Role of YKL-40 in bronchial smooth muscle remodeling in asthma

RATIONALE

Bronchial remodeling, including increased bronchial smooth muscle (BSM) mass, contributes to bronchial obstruction in asthma. However, its mechanisms are complex and remain controversial. Recently, a role of the chitinase 3-like 1 protein (YKL-40) has been evoked in asthma. Indeed, YKL-40 concentration was increased in asthmatic serum, and correlated with asthma severity and subepithelial membrane thickness. Nevertheless, the role of YKL-40 on BSM cells remains to be investigated.

OBJECTIVES

To evaluate whether YKL-40 altered the physiologic properties of BSM cells in asthma in vitro and ex vivo.

METHODS

We enrolled 40 subjects with asthma, 13 nonsmokers, and 16 smokers. BSM cells were derived from bronchial specimens obtained by either fiberoptic bronchoscopy or lobectomy. We assessed cell proliferation using BrdU, flow cytometry, and cell count; signaling intermediates using Western blot; cell migration using inserts, wound healing, and phalloidin staining; and cell synthesis using ELISA and Western blot. The involvement of protease activated receptor (PAR)-2 was evaluated using blocking antibody and dedicated lentiviral small hairpin RNA. We also determined the BSM area and the YKL-40 staining ex vivo using immunohistochemistry on biopsies from subjects with asthma and control subjects.

MEASUREMENTS AND MAIN RESULTS

We demonstrated that YKL-40 increased BSM cell proliferation and migration through PAR-2-, AKT-, ERK-, and p38-dependent mechanisms. The increased cell migration was higher in BSM cells of subjects with asthma than that of control subjects. Furthermore, YKL-40 epithelial expression was positively correlated with BSM mass in asthma.

CONCLUSIONS

This study indicates that YKL-40 promotes BSM cell proliferation and migration through a PAR-2-dependent mechanism.

Role of chitotriosidase (chitinase 1) under normal and disease conditions

Mammalian chitinases belong to the glycosyl hydrolase 18 family based on structural homology and the family includes a large number of bacterial and eukaryotic chitinases. Among the mammalian chitinases, chitotriosidase (CHIT1) and acidic mammalian chitinase (AMCase) are capable of hydrolyzing the β-(1, 4)-linkage between the adjacent N-acetyl glucosamine residues of chitin. CHIT1 is one of the most abundantly secreted proteins, being mainly produced by activated macrophages and epithelial cells. CHIT1 plays a pivotal role in the context of infectious disease including malaria and fungi infections as a host defense towards chitin in pathogen's cell structure and as a diagnostic marker of disease. In contrast, CHI1 released by activated Kupffer cells in liver could induce hepatic fibrosis and cirrhosis. Increased serum levels of CHIT1 were observed in patients with many disorders, including Gaucher's disease, bronchial asthma, and atherosclerosis. Therefore, CHIT1 seems to have dual (regulatory and pathogenic) roles depending on the disease and producing cell types during the inflammatory conditions.

YKL-40 is differentially expressed in human embryonic stem cells and in cell progeny of the three germ layers

The secreted glycoprotein YKL-40 participates in cell differentiation, inflammation, and cancer progression. High YKL-40 expression is reported during early human development, but its functions are unknown. Six human embryonic stem cell (hESC) lines were cultured in an atmosphere of low or high oxygen tension, in culture medium with or without basic fibroblast growth factor, and on feeder layers comprising mouse embryonic fibroblasts or human foreskin fibroblasts to evaluate whether hESCs and their progeny produced YKL-40 and to characterize YKL-40 expression during differentiation. Secreted YKL-40 protein and YKL-40 mRNA expression were measured by enzyme-linked immunosorbent assay (ELISA) and quantitative RT-PCR. Serial-sectioned colonies were stained for YKL-40 protein and for pluripotent hESC (OCT4, NANOG) and germ layer (HNF-3β, PDX1, CD34, p63, nestin, PAX6) markers. Double-labeling showed YKL-40 expression in OCT4-positive hESCs, PAX6-positive neuroectodermal cells, and HNF-3β-positive endodermal cells. The differentiating progeny showed strong YKL-40 expression. Abrupt transition between YKL-40 and OCT4-positive hESCs and YKL-40-positive ecto- and neuroectodermal lineages was observed within the same epithelial-like layer. YKL-40-positive cells within deeper layers lacked contact with OCT4-positive cells. YKL-40 may be important in initial cell differentiation from hESCs toward ectoderm and neuroectoderm, with retained epithelial morphology, whereas later differentiation into endoderm and mesoderm involves a transition into the deeper layers of the colony.

Cancer risk by combined levels of YKL-40 and C-reactive protein in the general population

Background:

YKL-40 and C-reactive protein (CRP) are biomarkers that may reflect cancer-related subclinical inflammation. We assessed elevated YKL-40 and CRP levels as combined risk predictors for cancer.

Methods:

We measured plasma YKL-40 and CRP at baseline in 8706 individuals from the Danish general population.

Results:

Hazard ratio (HR) of gastrointestinal cancer for a doubling of YKL-40 levels was 1.37 (95% CI: 1.17–1.61) and indifferent to adjustment for CRP levels. Hazard ratio of lung cancer for a doubling of CRP levels was 1.35 (1.17–1.56) and indifferent to adjustment for YKL-40 levels. Compared to individuals with both low CRP (<1.7 mg l⁻¹) and YKL-40 (<154 μg l⁻¹), individuals with high YKL-40 but low CRP had an HR of gastrointestinal cancer of 3.36 (1.70–6.64), whereas individuals with high CRP but low YKL-40 had an HR of lung cancer of 2.19 (1.24–3.87). The area under the receiver operating characteristic (ROC) curve was 0.68 for the ability of YKL-40 to predict gastrointestinal cancer and 0.67 for the ability of CRP to predict lung cancer.

Conclusion:

Elevated YKL-40 levels are associated with increased risk of gastrointestinal cancer, independently of CRP levels, whereas elevated CRP levels are associated with increased risk of lung cancer, independently of YKL-40 levels.