Inflammatory Cytokines Induce Production of CHI3L1 by Articular Chondrocytes

Elevated Serum Levels of YKL-40, YKL-39, and SI-CLP in Patients with Treatment Failure to DMARDs in Patients with Rheumatoid Arthritis

Around 30-60% of patients with rheumatoid arthritis (RA) present treatment failure to conventional synthetic disease-modifying antirheumatic drugs (csDMARDs). Chitinase-like proteins (CLPs) (YKL-40, YKL-39, SI-CLP) might play a role, as they are associated with the inflammatory process. This study aimed to evaluate CLP utility as a biomarker in the treatment failure of csDMARDs. A case-control study included 175 RA patients classified into two groups based on therapeutic response according to DAS28-ESR: responders (DAS28 < 3.2); non-responders (DAS28 ≥ 3.2). CLP serum levels were determined by ELISA. Multivariable logistic regression and receiver operating characteristic (ROC) curves were used to evaluate CLPs' utility as biomarkers of treatment failure. Non-responders presented higher levels of YKL-40, YKL-39, and SI-CLP compared with responders (all: p < 0.001). YKL-40 correlated positively with YKL-39 (rho = 0.39, p < 0.001) and SI-CLP (rho = 0.23, p = 0.011) and YKL-39 with SI-CLP (rho = 0.34, p < 0.001). The addition of CLPs to the regression models improves diagnostic accuracy (AUC 0.918) compared to models including only clinical classical variables (AUC 0.806) p < 0.001. Non-responders were positive for all CLPs in 35.86%. Conclusions: CLPs could be considered as a useful biomarker to assess treatment failure, due to their association with clinical variables and improvement to the performance of regression models.

YKL-40 in serum: a promising biomarker of juvenile SLE and strongly correlated with disease duration

BACKGROUND

The biological function of YKL-40 is not well determined in different inflammatory and autoimmune diseases; however, some data highlighted its possible connection with disease activity.

AIM

We investigated the diagnostic utility of serum YKL-40 in patients with SLE and examined its correlation with disease activity. Additionally, we examined any differences in serum YKL-40 levels between juvenile and adult SLE patients.

METHODS

We included 78 female patients with SLE and 42 controls. The level of YKL-40 in serum was measured by ELISA.

RESULTS

The serum YKL-40 level in SLE patients was significantly higher compared to the control group (9 (3) ng/mL vs. 5.5 (0.1) ng/mL; p < 0.001). YKL-40 showed excellent diagnostic utility with an AUC of 1 (p < 0.001) and a cutoff point of 5.6, providing sensitivity and specificity of 100%. YKL-40 was higher in adolescents and those with a positive family history of SLE (p = 0.01 for both) and positively correlated with disease duration (r = 0.45, p < 0.001). YKL-40 level was significantly higher in patients with photosensitivity, fever, vasculitis, blood disorders, positive anti-dsDNA, and APL ab (p < 0.05 for all). Conversely, patients with skin manifestations had a significantly lower YKL-40 (p = 0.004). In juvenile SLE, the AUC was 0.65 and a p-value of 0.01, and at a cutoff value of (8.7) ng/mL, the sensitivity and specificity were 72% and 60%, respectively.

CONCLUSION

YKL-40 in serum could be a promising biomarker in patients with SLE, especially in adolescent-onset cases. It is independently influenced by disease duration, anemia, thrombocytopenia, positive anti-dsDNA, and APL ab features.

Potential role of chitinase-3-like protein 1 (CHI3L1/YKL-40) in neurodegeneration and Alzheimer's disease

Chitinase-3-like protein 1 (CHI3L1/YKL-40) has long been known as a biomarker for early detection of neuroinflammation and disease diagnosis of Alzheimer's disease (AD). In the brain, CHI3L1 is primarily provided by astrocytes and heralds the reactive, neurotoxic state triggered by inflammation and other stress signals. However, how CHI3L1 acts in neuroinflammation or how it contributes to AD and relevant neurodegenerative conditions remains unknown. In peripheral tissues, our group and others have uncovered that CHI3L1 is a master regulator for a wide range of injury and repair events, including the innate immunity pathway that resembles the neuroinflammation process governed by microglia and astrocytes. Based on assessment of current knowledge regarding CHI3L1 biology, we hypothesize that CHI3L1 functions as a signaling molecule mediating distinct neuroinflammatory responses in brain cells and misfunctions to precipitate neurodegeneration. We also recommend future research directions to validate such assertions for better understanding of disease mechanisms.

Differential expression of Chitinase 3-Like 1 protein in appendicitis and appendix carcinomas

BACKGROUND

Chitinase 3-Like 1 (CHI3L1) has been used as an inflammatory biomarker for a variety of diseases, but its expression in acute appendicitis and appendix carcinomas remains unclear.

METHODS

Sixty cases of patients were studied, including 46 acute appendicitis and 14 appendix carcinomas. We divided the acute appendicitis group into acute uncomplicated appendicitis (AUA), suppurative appendicitis (SA), and gangrenous appendicitis (GA). The appendix carcinoma group was divided into appendiceal neuroendocrine neoplasms (ANENs) and appendiceal mucinous neoplasms (AMN). Controls were 32 healthy donors. Blood neutrophil to lymphocyte ratio (NLR), CHI3L1, C-reactive protein (CRP), interleukin-6 (IL-6), and serum amyloid A (SAA) were measured in the patients. Meanwhile, immunohistochemistry and immunofluorescence were used to identify the expression level and location of CHI3L1 in different cell types in appendix tissues.

RESULTS

Compared with the controls, CHI3L1 serum levels were up-regulated in SA, GA, and AMN groups, while no significant difference was observed in the AUA and ANEN groups. Immunofluorescence revealed that CHI3L1 expression was high in macrophages and adenocarcinoma cells of appendix tissues but not in the neuroendocrine carcinoma tissues. Moreover, levels of NLR and CRP in the SA and GA groups were considerably higher than in the control group. IL-6 and SAA in SA, GA, ANENs, and AMN groups were also increased compared with the control group. In addition, CHI3L1 displayed good performance in predicting appendicitis, with an AUC of 0.862.

CONCLUSION

CHI3L1 was highly expressed in acute appendicitis and appendiceal mucinous neoplasms, which can be used as a novel biomarker predicting appendicitis.

A novel biomarker in acute cholecystitis: YKL-40

BACKGROUND

The lack of a specific biomarker that can be used in the diagnosis of acute cholecystitis, a common cause of admission to the emergency department, delays physician efforts to diagnose and treat these patients. Therefore, the aim of this study was to measure plasma YKL-40 levels and investigate their diagnostic value in patients with acute cholecystitis (AC).

METHODS

This study was carried out between February 2020 and September 2020 in the adult emergency department of a tertiary university hospital. Permission was obtained from the Ethics Committee of Scientific Research on 03/02/2020 with Decision No. 03/16. The study included 80 patients who were diagnosed with acute cholecystitis and 80 healthy volunteers without known chronic diseases.

RESULTS

The median YKL-40 protein level was 798.66 pq/mL in the patient group and 392.45 pq/mL in the control group. A statistically significant difference in YKL-40 protein levels was found between the two groups. YKL-40 protein levels were significantly higher in patients diagnosed with acute cholecystitis than in healthy individuals (p < 0.001). A positive correlation was found between YKL-40 protein levels and ALT, AST, LDH, and GGT levels (r = 0.272, p = 0.015; r = 0.397, p < 0.001; r = 0.386, p < 0.001; and r = 0.264, p = 0.018; respectively).

CONCLUSION

When evaluated together with physical examination, radiological imaging and other laboratory parameters, we think that plasma YKL-40 levels can be used effectively in the diagnosis of acute cholecystitis.

YKL-40 and neuron-specific enolase in neurodegeneration and neuroinflammation

Neurodegenerative diseases comprise a large number of disorders with high impact on human health. Neurodegenerative processes are caused by various etiological factors and differ in their clinical presentation. Neuroinflammation is widely discussed as both a cause and a consequence in the manifestation of these disorders. The interplay between the two entities is considered as a major contributor to the ongoing disease progression. An attentive search and implementation of new and reliable markers specific for the processes of inflammation and degeneration is still needed. YKL-40 is a secreted glycoprotein produced by activated glial cells during neuroinflammation. Neuron-specific enolase (NSE), expressed mainly by neuronal cells, is a long-standing marker for neuronal damage. The aim of this review is to summarize, clarify, and evaluate the potential significance and relationship between YKL-40 and NSE as biomarkers in the monitoring and prognosis of a set of neurological diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis. YKL-40 appears to be a more reliable biomarker in neurological diseases than NSE. The more prominent expression pattern of YKL-40 could be explained with the more obvious involvement of glial cells in pathological processes accompanying each neurodegenerative disease, whereas reduced NSE levels are likely related to low metabolic activity and increased death of neurons.

Plasma levels of YKL-40 as a prognostic factor in childhood acute lymphoblastic leukemia

YKL-40, also known as chitinase-3-like protein 1 (CHI3L1), is an inflammatory glycoprotein secreted by different types of cells, such as inflammatory cells. The levels of this protein are elevated in the serum or plasma of patients with different types of cancer, and high concentrations are associated with poor prognosis and short survival in patients with liver, breast, lung, bladder and endometrial cancers. In Mexico, acute lymphoblastic leukemia (ALL) is the most common type of cancer affecting the pediatric population. The prognosis of patients with ALL is difficult to establish. Hence, the objective of the present study was to analyze the plasma levels of YKL-40 in Mexican children with ALL and investigate its role as a prognostic factor. A case-control study was performed in a population of 90 children aged 1-18 years, among whom 45 had ALL and 45 were hematologically healthy. The levels of YKL-40 in plasma samples were measured using ELISA and were found to be significantly higher in children with ALL compared with those in controls (P<0.0001). Children with ALL who had high plasma levels of YKL-40 (≥36.34 ng/ml) had shorter survival compared with those with low levels (<36.34 ng/ml; P<0.05). The findings of the present study revealed that the YKL-40 plasma level, age/initial leukocyte count and central nervous system invasion were associated with the prognosis of children with ALL [odds ratio (OR)=6.06, 95% confidence interval (CI): 1.1-31.6, P=0.03; OR=8.53, 95% CI: 1.2-58.2, P=0.03; and OR=6.45, 95% CI: 1.01-41.2, P=0.04, respectively]. Therefore, YKL-40 plasma levels may serve as a prognostic biomarker in pediatric patients with ALL.

Can YKL-40 be used as a biomarker for interstitial lung disease?: A systematic review and meta-analysis

BACKGROUND

Interstitial lung disease (ILD) has a poor prognosis and lacks specific biomarkers for early diagnosis, assessment of disease severity, and prognosis. YKL-40 levels were found to be elevated in patients with ILD, but these results are inconsistent. Therefore, we conducted a systematic review and meta-analysis to accurately study the relation between YKL-40 and ILD.

METHODS

We performed a systematic literature search in many databases (PubMed, Embase, the China National Knowledge Infrastructure, and Wanfang databases) and commercial Internet search engines to identify studies involving the role of YKL-40 in patients with ILD. The weighted mean difference with its 95% confidence interval were used to investigate the effect sizes. If obvious heterogeneity was found in the meta-analysis, the level of YKL-40 was directly compared by the Mann-Whitney test.

RESULTS

Sixteen eligible articles were finally identified. The results showed that the serum YKL-40 levels of patients with idiopathic pulmonary fibrosis, connective tissue-related ILD, sarcoidosis, cryptogenic tissue pneumonia, asbestosis-ILD, and idiopathic nonspecific interstitial pneumonia were higher than those in controls, but there was no increase in patients with pulmonary alveolar proteinosis. We also found that there are certain differences in the serum YKL-40 levels in patients with different types of ILD. The results showed that the bronchoalveolar lavage fluid YKL-40 levels of patients with idiopathic pulmonary fibrosis were significantly higher than that in controls. A systematic review indicated that there were correlations between the serum YKL-40 levels and lung function in patients with different ILD. In addition, YKL-40 may be used as a valuable biomarker for survival, with risk ratios ranging from 1.006 to 10.9.

CONCLUSIONS

This study suggests that YKL-40 may be a useful biomarker for the diagnosis and prognosis of ILD.

Efficacy of chitinase-3-like protein 1 as an in vivo bone formation predictable marker of maxillary/mandibular bone marrow stromal cells

Introduction

Maxillary/mandibular bone marrow stromal cells (MBMSCs) are a useful cell source for bone regeneration in the oral and maxillofacial region. To further ensure the clinical application of MBMSCs in bone regenerative therapy, it is important to determine the bone formation capacity of MBMSCs before transplantation. The aim of this study is to identify the molecular marker that determines the in vivo bone formation capacity of MBMSCs.

Methods

The cell growth, cell surface antigens, in vitro and in vivo bone formation capacity of MBMSCs were examined. The amount of chitinase-3-like protein 1 (CHI3L1) secreted into the conditioned medium was quantified. The effects of CHI3L1 on the cell growth and osteogenic differentiation potential of MBMSCs and on the cell growth and migration of vascular endothelial cells and fibroblasts were examined.

Results

The cell growth, and in vitro and in vivo bone formation capacity of the cells treated with different conditions were observed. MBMSCs that secreted a large amount of CHI3L1 into the conditioned medium tended to have low in vivo bone formation capacity, whereas MBMSCs that secreted a small amount of CHI3L1 had greater in vivo bone formation capacity. CHI3L1 promoted the migration of vascular endothelial cells, and the cell growth and migration of fibroblasts.

Conclusion

Our study indicates that the in vitro osteogenic differentiation capacity of MBMSCs and the in vivo bone formation capacities of MBMSCs were not necessarily correlated. The transplantation of high CHI3L1 secretory MBMSCs may suppress bone formation by inducing fibrosis at the site. These results suggest that the CHI3L1 secretion levels from MBMSCs may be used as a predictable marker of bone formation capacity in vivo.

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In vitro and in vivo bone formation capacities of MBMSCs were not correlated.

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MBMSCs with high CHI3L1 secretion tended to have low in vivo bone formation.

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MBMSCs with low CHI3L1 secretion tended to have high in vivo bone formation.

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CHI3L1 can be in vivo bone formation capacity predictable marker of MBMSCs.

CSF levels of HoxB3 and YKL-40 may predict conversion from clinically isolated syndrome to relapsing remitting multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) often initiates with an acute episode of neurological disturbance, known as clinically isolated syndrome (CIS). There is an unmet need for biomarkers that differentiate patients who will convert to MS and who will remain as CIS after the first attack.

METHODS

First attack serum and cerebrospinal fluid (CSF) samples of 33 CIS patients were collected and these patients were divided as those who converted to MS (CIS-MS, n=17) and those who continued as CIS (CIS-CIS, n=16) in a 3-year follow-up period. Levels of homeobox protein Hox-B3 (HoxB3) and YKL-40 were measured by ELISA in samples of CIS-CIS, CIS-MS, relapsing remitting MS (RRMS) patients (n=15) and healthy controls (n=20).

RESULTS

CIS-CIS patients showed significantly reduced CSF levels of YKL-40 and increased serum/CSF levels of HoxB3 compared with CIS-MS and RRMS patients. CIS-MS and RRMS patients had comparable YKL-40 and HoxB3 level profiles. Receiver operating characteristic (ROC) curve analysis showed the highest sensitivity for CSF HoxB3 measurements in prediction of CIS-MS conversion. Kaplan-Meier analysis demonstrated that CIS patients with lower CSF HoxB3 (<3.678 ng/ml) and higher CSF YKL-40 (>654.9 ng/ml) displayed a significantly shorter time to clinically definite MS.

CONCLUSION

CSF levels of HoxB3 and YKL-40 appear to predict CIS to MS conversion, especially when applied in combination. HoxB3, which is a transcription factor involved in immune cell activity, stands out as a potential candidate molecule with biomarker capacity for MS.

Chitinase 3-like 1 and neurofilament light chain in CSF and CNS atrophy in MS

Objective

To investigate cross-sectional associations of CSF levels of neurofilament light chain (NfL) and of the newly emerging marker chitinase 3–like protein 1 (CHI3L1) with brain and spinal cord atrophy, which are established MRI markers of disease activity in MS, to study CHI3L1 and NfL in relapsing (RMS) and progressive MS (PMS), and to assess the expression of CHI3L1 in different cell types.

Methods

In a single-center study, 131 patients with MS (42 RMS and 89 PMS) were assessed for NfL and CHI3L1 concentrations in CSF, MRI-based spinal cord and brain volumetry, MS subtype, age, disease duration, and disability. We included 42 matched healthy controls receiving MRI. CHI3L1 expression of human brain cell types was examined in 2 published single-cell RNA sequencing data sets.

Results

CHI3L1 was associated with spinal cord volume (B = −1.07, 95% CI −2.04 to −0.11, p = 0.029) but not with brain volumes. NfL was associated with brain gray matter (B = −7.3, 95% CI −12.0 to −2.7, p = 0.003) but not with spinal cord volume. CHI3L1 was suitable to differentiate between progressive or relapsing MS (p = 0.015, OR 1.0103, CI for OR 1.002–1.0187), and its gene expression was found in MS-associated microglia and macrophages and in astrocytes of MS brains.

Conclusions

NfL and CHI3L1 in CSF were differentially related to brain and spinal cord atrophy. CSF CHI3L1 was associated with spinal cord volume loss and was less affected than NfL by disease duration and age, whereas CSF NfL was associated with brain gray matter atrophy. CSF NfL and CHI3L1 measurement provides complementary information regarding brain and spinal cord volumes.

Classification of evidence

This study provides Class II evidence that CSF CHI3L1 is associated with spinal cord volume loss and that CSF NfL is associated with gray matter atrophy.

CHI3L1 in the pathophysiology and diagnosis of liver diseases

Chitinase 3-like protein 1(CHI3L1) participates in physiological and pathophysiological process, such as cell survival, cell proliferation, tissue remodeling, angiogenesis, etc. Some studies demonstrated that CHI3L1 is liver-enriched and has better application value in staging liver fibrosis than platelet ratio index(APRI) and fibrosis-4 index(FIB-4) and that CHI3L1 can be used in monitoring the prognosis of hepatocellular carcinoma (HCC). In this review, we summarized the pathophysiological role and the diagnostic value of CHI3L1 in liver fibrosis in different background and HCC.

Runx3 regulates chondrocyte phenotype by controlling multiple genes involved in chondrocyte proliferation and differentiation

Chondrocytes are the sole cell type present within cartilage, and play pivotal roles in controlling the formation and composition of health cartilage. Chondrocytes maintain cartilage homeostasis through proliferating, differentiating and synthesizing different types of extracellular matrices. Thus, the coordinated proliferation and differentiation of chondrocytes are essential for cartilage growth, repair and the conversion from cartilage to bone during the processes of bone formation and fracture healing. Runx3, a transcription factor that belongs to the Runx family, is significantly upregulated at the onset of cartilage mineralization and regulates both early and late markers of chondrocyte maturation. Therefore, Runx3 may serve as an accelerator of chondrocyte differentiation and maturation. However, the underlying molecular mechanism of Runx3 in regulating chondrocyte proliferation and differentiation remains largely to be elucidated. In the present study, we used state-of-the-art RNA-seq technology combined with validation methods to investigate the effect of Runx3 overexpression or silencing on primary chondrocyte proliferation and differentiation, and demonstrated that Runx3 overexpression possibly inhibited chondrocyte proliferation but accelerated differentiation, whereas Runx3 silencing possibly promoted chondrocyte proliferation but suppressed differentiation. Furthermore, Runx3 overexpression possibly decreased the expression levels of Sox9 and its downstream genes via Sox9 cartilage-specific enhancers, and vice versa for Runx3 silencing.

Characterization of the interleukin-17 effect on articular cartilage in a translational model: an explorative study

Background

Osteoarthritis (OA) is a progressive, chronic disease characterized by articular cartilage destruction. The pro-inflammatory cytokine IL-17 levels have been reported elevated in serum and synovial fluid of OA patients and correlated with increased cartilage defects and bone remodeling. The aim of this study was to characterize an IL-17-mediated articular cartilage degradation ex-vivo model and to investigate IL-17 effect on cartilage extracellular matrix protein turnover.

Methods

Full-depth bovine femoral condyle articular cartilage explants were cultured in serum-free medium for three weeks in the absence, or presence of cytokines: IL-17A (100 ng/ml or 25 ng/ml), or 10 ng OSM combined with 20 ng/ml TNFα (O + T). RNA isolation and PCR analysis were performed on tissue lysates to confirm IL-17 receptor expression. GAG and ECM-turnover biomarker release into conditioned media was assessed with dimethyl methylene blue and ELISA assays, respectively. Gelatin zymography was used for matrix metalloproteinase (MMP) 2 and MMP9 activity assessment in conditioned media, and shotgun LC-MS/MS for identification and label-free quantification of proteins and protein fragments in conditioned media. Western blotting was used to validate MS results.

Results

IL-17RA mRNA was expressed in bovine full-depth articular cartilage and the treatment with IL-17A did not interfere with metabolic activity of the model. IL-17A induced cartilage breakdown; conditioned media GAG levels were 3.6-fold-elevated compared to untreated. IL-17A [100 ng/ml] induced ADAMTS-mediated aggrecan degradation fragment release (14-fold increase compared to untreated) and MMP-mediated type II collagen fragment release (6-fold-change compared to untreated). MS data analysis revealed 16 differentially expressed proteins in IL-17A conditioned media compared to untreated, and CHI3L1 upregulation in conditioned media in response to IL-17 was confirmed by Western blotting.

Conclusions

We showed that IL-17A has cartilage modulating potential. It induces collagen and aggrecan degradation indicating an upregulation of MMPs. This was confirmed by zymography and mass spectrometry data. We also showed that the expression of other cytokines is induced by IL-17A, which provide further insight to the pathways that are active in response to IL-17A. This exploratory study confirms that IL-17A may play a role in cartilage pathology and that the applied model may be a good tool to further investigate it.

Coix lachryma-jobi extract ameliorates inflammation and oxidative stress in a complete Freund's adjuvant-induced rheumatoid arthritis model

Context: Adlay seed [Job's tears, Coix lachryma-jobi L. var. ma-yuen Stapf (Poaceae)] is a Traditional Chinese Medicine, which has been investigated to treat inflammatory diseases and rheumatism.Objective: This study evaluates the ameliorative effects of adlay seed extract (ASE) in a complete Freund's adjuvant (CFA)-induced rheumatoid arthritis (RA) rats.Materials and methods: The RA Sprague-Dawley rat model was induced and randomly divided into six groups with or without ASE treatment (50, 100 or 200 mg/kg). After 28 d administration, the symptoms, biochemical parameters and molecular mechanisms were investigated.Results: The values of paw oedema, PGE₂ and MMP-3 decreased from 1.46 ± 0.04 to 0.66 ± 0.07 cm³, from 126.2 ± 11.48 to 79.71 ± 6.8 pg/mL and from 142.7 ± 8.36 to 86.51 ± 5.95 ng/mL, respectively; the values of body weight increased from 177.25 ± 5.94 to 205 ± 6.52 g in HASE group. In addition, treatment of ASE reduced the levels of pro-inflammatory cytokines (IL-1β, TNF-α, IL-6, MCP-1), and increased the activities of antioxidant enzyme (GSH-Px, SOD, and CAT). Furthermore, ASE could suppress the mRNA expression of COX-2 and CHI3L1 and improve the mRNA expression of CAT and GPx-1 in ankle tissues of RA rats.Discussion and conclusions: For the first time, our results indicated ASE exerts anti-RA effects via inhibiting pro-inflammatory factors and alleviating oxidative stress. Our finding sheds light on the research and development of anti-RA functional foods from adlay seed.

Astrogliosis Releases Pro-Oncogenic Chitinase 3-Like 1 Causing MAPK Signaling in Glioblastoma

Although reactive astrocytes constitute a major component of the cellular environment in glioblastoma, their function and crosstalk to other components of the environment is still poorly understood. Gene expression analysis of purified astrocytes from both the tumor core and non-infiltrated cortex reveals a tumor-related up-regulation of Chitinase 3-like 1 (CHI3L1), a cytokine which is related to inflammation, extracellular tissue remodeling, and fibrosis. Further, we established and validated a co-culture model to investigate the impact of reactive astrocytes within the tumor microenvironment. Here we show that reactive astrocytes promote a subtype-shift of glioblastoma towards the mesenchymal phenotype, driving mitogen-activated protein kinases (MAPK) signaling as well as increased proliferation and migration. In addition, we demonstrate that MAPK signaling is directly caused by a CHI3L1-IL13RA2 co-binding, which leads to increased downstream MAPK and AKT signaling. This novel microenvironmental crosstalk highlights the crucial role of non-neoplastic cells in malignant brain tumors and opens up new perspectives for targeted therapies in glioblastoma.

Roles of chitinase 3-like 1 in the development of cancer, neurodegenerative diseases, and inflammatory diseases

Chitinase 3-like 1 (CHI3L1) is a secreted glycoprotein that mediates inflammation, macrophage polarization, apoptosis, and carcinogenesis. The expression of CHI3L1 is strongly increased by various inflammatory and immunological conditions, including rheumatoid arthritis, multiple sclerosis, Alzheimer's disease, and several cancers. However, its physiological and pathophysiological roles in the development of cancer and neurodegenerative and inflammatory diseases remain unclear. Several studies have reported that CHI3L1 promotes cancer proliferation, inflammatory cytokine production, and microglial activation, and that multiple receptors, such as advanced glycation end product, syndecan-1/αVβ3, and IL-13Rα2, are involved. In addition, the pro-inflammatory action of CHI3L1 may be mediated via the protein kinase B and phosphoinositide-3 signaling pathways and responses to various pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin-1β, interleukin-6, and interferon-γ. Therefore, CHI3L1 could contribute to a vast array of inflammatory diseases. In this article, we review recent findings regarding the roles of CHI3L1 and suggest therapeutic approaches targeting CHI3L1 in the development of cancers, neurodegenerative diseases, and inflammatory diseases.

Synovial fluid proteome changes in ACL injury-induced posttraumatic osteoarthritis: Proteomics analysis of porcine knee synovial fluid

Surgical transection of the anterior cruciate ligament (ACL) in the porcine model leads to posttraumatic osteoarthritis if left untreated. However, a recently developed surgical treatment, bridge-enhanced ACL repair, prevents further cartilage damage. Since the synovial fluid bathes all the intrinsic structures of knee, we reasoned that a comparative analysis of synovial fluid protein contents could help to better understand the observed chondroprotective effects of the bridge-enhanced ACL repair. We hypothesized that post-surgical changes in the synovial fluid proteome would be different in the untreated and repaired knees, and those changes would correlate with the degree of cartilage damage. Thirty adolescent Yucatan mini-pigs underwent unilateral ACL transection and were randomly assigned to either no further treatment (ACLT, n = 14) or bridge-enhanced ACL repair (BEAR, n = 16). We used an isotopically labeled high resolution LC MS/MS-based proteomics approach to analyze the protein profile of synovial fluid at 6 and 12 months after ACL transection in untreated and repaired porcine knees. A linear mixed effect model was used to compare the normalized protein abundance levels between the groups at each time point. Bivariate linear regression analyses were used to assess the correlations between the macroscopic cartilage damage (total lesion area) and normalized abundance levels of each of the identified secreted proteins. There were no significant differences in cartilage lesion area or quantitative abundance levels of the secreted proteins between the ACLT and BEAR groups at 6 months. However, by 12 months, greater cartilage damage was seen in the ACLT group compared to the BEAR group (p = 0.005). This damage was accompanied by differences in the abundance levels of secreted proteins, with higher levels of Vitamin K-dependent protein C (p = 0.001), and lower levels of Apolipoprotein A4 (p = 0.021) and Cartilage intermediate layer protein 1 (p = 0.049) in the ACLT group compared to the BEAR group. There were also group differences in the secreted proteins that significantly changed in abundance between 6 and 12 months in ACLT and BEAR knees. Increased concentration of Ig lambda-1 chain C regions and decreased concentration of Hemopexin, Clusterin, Coagulation factor 12 and Cartilage intermediate layer protein 1 were associated with greater cartilage lesion area. In general, ACLT knees had higher concentrations of pro-inflammatory proteins and lower concentrations of anti-inflammatory proteins than BEAR group. In addition, the ACLT group had a lower and declining synovial concentrations of CILP, in contrast to a consistently high abundance of CILP in repaired knees. These differences suggest that the knees treated with bridge-enhanced ACL repair may be maintaining an environment that is more protective of the extracellular matrix, a function which is not seen in the ACLT knees.

NF-κB, Mesenchymal Differentiation and Glioblastoma

Although glioblastoma (GBM) has always been recognized as a heterogeneous tumor, the advent of largescale molecular analysis has enabled robust categorization of this malignancy into several specific subgroups. Among the subtypes designated by expression profiling, mesenchymal tumors have been associated with an inflammatory microenvironment, increased angiogenesis, and resistance to therapy. Nuclear factor-κB (NF-κB) is a ubiquitous transcription factor that plays a prominent role in mediating many of the central features associated with mesenchymal differentiation. This review summarizes the mechanisms by which NF-κB proteins and their co-regulating partners induce the transcriptional network that underlies the mesenchymal phenotype. Moreover, both the intrinsic changes within mesenchymal GBM cells and the microenvironmental factors that modify the overall NF-κB response are detailed.

Chitinase 3-Like-1-Deficient Splenocytes Deteriorated the Pathogenesis of Acute Graft-Versus-Host Disease via Regulating Differentiation of Tfh Cells

Acute graft-versus-host disease (aGVHD) is an intractable complication in transplant patients, limiting the efficacy of this therapy. Chitinase 3-like-1 (CHI3L1), a member of the glycosyl hydrolase 18 family that lacks chitinase activity, plays a critical role in a variety of inflammatory diseases. Here, we investigated the in vitro and in vivo effects of CHI3L1 on the development of aGVHD. In this study, mixed lymphocyte reactions (MLR) in vitro showed that CHI3L1 deficiency in CD4⁺ T cell promoted the production of interferon (IFN)-γ and T follicular helper (Tfh)-related cytokines such as interleukin-6 (IL-6) and interleukin-21 (IL-21). Meanwhile, the inducible Tfh cell population increased remarkably in CHI3L1-KO CD4⁺ T cells' induction group, compared with WT group. Then, in the murine acute GVHD model, we found that CHI3L1 deficiency in donor splenocytes dramatically increased the severity of aGVHD through enhancing Tfh cell differentiation. Moreover, at mRNA and protein levels, we defined several molecules that may account for the enhanced ability of CHI3L1-KO splenocytes to migrate into target organs and produce IFN-γ and Tfh-related cytokines and chemokines, such as IL-6, IL-21, and CXCL13. Expression of inducible co-stimulator (ICOS) and B cell lymphoma 6 (Bcl6) increased in the skin, the intestine, the lung, and the liver from CHI3L1-KO splenocyte-treated aGVHD mice. Therefore, these results strongly imply that CHI3L1 levels in donor cells may be related to the risk of aGVHD and targeting CHI3L1 represents a novel therapeutic strategy for controlling aGVHD progression.

K284-6111 prevents the amyloid beta-induced neuroinflammation and impairment of recognition memory through inhibition of NF-κB-mediated CHI3L1 expression

BACKGROUND

Alzheimer's disease, which is pathologically characterized by an excessive accumulation of amyloid beta (Aβ) fibrils, is a degenerative brain disease and the most common cause of dementia. In a previous study, it was reported that an increased level of CHI3L1 in plasma was found in AD patients. We investigated the inhibitory effect of 2-({3-[2-(1-cyclohexen-1-yl)ethyl]-6,7-dimethoxy-4-oxo-3,4-dihydro-2-quinazolinyl}sulfanyl)-N-(4-ethylphenyl)butanamide (K284-6111), an inhibitor of chitinase 3 like 1 (CHI3L1), on memory impairment in Aβ1-42-infused mice, and microglial BV-2 cells and astrocytes.

METHODS

We examined whether K284-6111 (3 mg/kg given orally for 4 weeks) prevents amyloidogenesis and memory loss in Aβ1-42-induced AD mice model. After intracerebroventrical (ICV) infusion of Aβ1-42 for 14 days, the cognitive function was assessed by the Morris water maze test and passive avoidance test. K284-6111 treatment was found to reduce Aβ1-42-induced memory loss.

RESULTS

A memory recovery effect was found to be associated with the reduction of Aβ1-42-induced expression of inflammatory proteins (iNOS, COX-2, GFAP, and Iba-1) and the suppression of CHI3L1 expression in the brain. Additionally, K284-6111 reduced Aβ1-42-induced β-secretase activity and Aβ generation. Lipopolysaccharide (LPS)-induced (1 μg/mL) expression of inflammatory (COX-2, iNOS, GFAP, Iba-1) and amyloidogenic proteins (APP, BACE1) were decreased in microglial BV-2 cells and cultured astrocytes by the K284-6111 treatment (0.5, 1, and 2 μM). Moreover, K284-6111 treatment suppressed p50 and p65 translocation into the nucleus, and phosphorylation of IκB in vivo and in vitro.

CONCLUSION

These results suggest that CHI3L1 inhibitor could be an applicable intervention drug in amyloidogenesis and neuroinflammation, thereby preventing memory dysfunction via inhibition of NF-κB.

Chitinase 3-like-1 promotes intrahepatic activation of coagulation through induction of tissue factor in mice

Coagulation is a critical component in the progression of liver disease. Identification of key molecules involved in the intrahepatic activation of coagulation (IAOC) will be instrumental in the development of effective therapies against liver disease. Using a mouse model of concanavalin A (ConA)-induced hepatitis, in which IAOC plays an essential role in causing liver injury, we uncovered a procoagulant function of chitinase 3-like 1 (Chi3l1). Chi3l1 expression is dramatically elevated after ConA challenge, which is dependent on ConA-induced T cell activation and the resulting interferon γ and tumor necrosis factor α productions. Compared with wild-type mice, Chi3l1-/- mice show less IAOC, reduced tissue factor (TF) expression, and attenuated liver injury. Reconstituting Chi3l1-/- mice with recombinant TF triggers IAOC and augments liver injury.

CONCLUSION

Our data demonstrate that Chi3l1, through induction of TF via mitogen-activated protein kinase activation, promotes IAOC and tissue injury. (Hepatology 2018;67:2384-2396).

YKL-40 as a Potential Biomarker and a Possible Target in Therapeutic Strategies of Alzheimer's Disease

Background:

Growing body of evidence suggests that the pathogenesis of Alzheimer’s disease (AD), a progressing neurodegenerative condition, is not limited to the neuronal compartment, but also involves various immunological mechanisms. Insoluble Aβ aggregates in the brain can induce the activation of microglia, resulting in the synthesis of proinflammatory mediators, which further can stimulate astrocytic expression of YKL-40. Therefore, the aim of the current review is to present up-to-date data about the role of YKL-40 as a biomarker of AD as well as the possibility of therapeutic strategies targeting neuroinflammation.

Objective/Methods:

We searched PubMed articles for the terms “YKL-40”, “neurodegeneration”, “neuroinflammation” and “Alzheimer’s disease”, and included papers focusing on this review’s scope.

Results:

Recent studies indicate that CSF concentrations of YKL-40 were significantly higher in AD patients than in cognitively normal individuals and correlated with dementia biomarkers, such as tau proteins and amyloid beta. Determination of YKL-40 CSF concentration may be also helpful in differentiation between types of dementia and in the distinction of patients in the stable phase of MCI from those who progressed to dementia. Moreover, significantly increased levels of YKL-40 mRNA were found in AD brains in comparison with non-demented controls. Additionally, it was suggested that anti-inflammatory treatment might relief the symptoms of AD and slow its progression.

Conclusion:

Based on the recent knowledge, YKL-40 might be useful as a possible biomarker in the diagnosis and prognosis of AD. Modulation of risk factors and targeting of immune mechanisms, including systemic inflammation could lead to future preventive or therapeutic strategies for AD.

Chitinase-like proteins as regulators of innate immunity and tissue repair: helpful lessons for asthma?

Chitinases and chitinase-like proteins (CLPs) belong to the glycoside hydrolase family 18 of proteins. Chitinases are expressed in mammals and lower organisms, facilitate chitin degradation, and hence act as host-defence enzymes. Gene duplication and loss-of-function mutations of enzymatically active chitinases have resulted in the expression of a diverse range of CLPs across different species. CLPs are genes that are increasingly associated with inflammation and tissue remodelling not only in mammals but also across distant species. While the focus has remained on understanding the functions and expression patterns of CLPs during disease in humans, studies in mouse and lower organisms have revealed important and overlapping roles of the CLP family during physiology, host defence and pathology. This review will summarise recent insights into the regulatory functions of CLPs on innate immune pathways and discuss how these effects are not only important for host defence and tissue injury/repair after pathogen invasion, but also how they have extensive implications for pathological processes involved in diseases such as asthma.

Circulating tumor cell interactions with macrophages: implications for biology and treatment

Cancer and metastasis are closely associated with inflammation. Macrophages are important effector cells in enhancing tumor proliferation, invasion and providing protection against the immune system. Despite advanced knowledge of tumor-macrophage interactions, the role of macrophages in emergence and invasion of circulating tumor cells (CTCs) is not known. A series of six CTC cell lines have been derived from blood of patients with extensive disease small cell lung cancer (ED-SCLC) in our lab, most likely representing a homogenous cell population of the actual metastasis-initiating cells (MIC) of CTCs. SCLC has an unfavorable prognosis due to rapid dissemination and early chemoresistant relapses. SCLC CTCs recruit macrophages and elicit secretion of various cytokines and the six CTC lines express chitinase-3-like-1 (CHI3L1), vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP9) in abundance. CHI3L1 is cytokine/growth factor expressed in inflammation and cancer and found to be correlated to metastasis and a dismal prognosis. In conclusion, SCLC CTCs have acquired the essential means for aggressiveness and invasion in a tumor microenvironment specifically shaped by macrophages and inflammation.

Circulating Bone-related Markers and YKL-40 Versus HER2 and TOPO2a in Bone Metastatic and Nonmetastatic Breast Cancer: Diagnostic Implications

BACKGROUND

The bone represents one of the most common sites of metastases in breast cancer. The aim of the current study was to evaluate the diagnostic potential of several circulating markers to detect metastasis to bones in patients with breast cancer.

PATIENTS AND METHODS

Receptor activator of Nuclear Factor-kappa β (NF-Kβ) ligand (RANKL), osteoprotegrin (OPG), vitamin D (VIT D), Chitinase-3-like protein 1; also known as YKL-40, topoisomerase IIα (TOPO2a), and human epidermal growth factor receptor 2 (HER2) were measured in blood samples obtained from 122 patients with breast cancer and 25 healthy controls.

RESULTS

All biomarkers were significantly elevated in patients with breast cancer with bone metastasis compared with nonmetastatic patients except YKL-40. RANKL had the highest diagnostic performance for bone metastasis detection with an area under the curve of 97.3, a sensitivity of 85%, and a specificity of 98.6%. Furthermore, logistic regression analysis resulted in a model of RANKL combined with HER2 that had even higher discriminatory power of metastasis to bones than that of RANKL alone. Overall correct classification of the model was 98.9%.

CONCLUSION

We recommend that measuring RANKL together with HER2 can be routinely applied to allow early detection of bone metastases in patients with breast cancer.

Serum YKL-40 as a marker of liver fibrosis in patients with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a common cause of chronic non-viral liver disease. YKL-40, chitinase-like protein expressed in multiple tissues including liver, is involved in cell proliferation, inflammation and remodeling of the extracellular matrix. The aim of this study was to assess whether serum YKL-40 levels are associated with liver fibrosis in NAFLD patients. Serum YKL-40 levels were quantified in 111 NAFLD patients and 23 HCC patients with NAFLD. To identify the source of YKL-40, immunofluorescence staining of liver specimens from NAFLD patients was performed. Serum YKL-40 levels in NAFLD patients increased in accordance with the progression of liver fibrosis. Multivariate analysis revealed that YKL-40 was one of the independent factors significantly associated with severe fibrosis (F3-4). We established a new predictive model for fibrosis of NAFLD, using logistic regression analysis: YKL-40 based fibrosis score = −0.0545 + type IV collagen 7s * 0.3456 + YKL-40 * 0.0024. Serum YKL-40 levels of HCC patients with non-cirrhotic NAFLD were significantly higher than those without HCC. Immunofluorescence staining showed that YKL-40 was expressed by macrophages in liver tissue of NAFLD patients. In conclusion, macrophage-derived YKL-40 is a feasible biomarker of liver fibrosis in NAFLD patients.

Estimation of Serum YKL-40 by Real-Time Surface Plasmon Resonance Technology in North-Indian Asthma Patients

BACKGROUND

Many studies reported for estimating serum YKL-40 using ELISA or RIA methods. This study introduces the plausible utilization of real-time surface plasmon resonance (SPR) technology in investigating the expression of serum YKL-40 protein levels and ELISA method for serum IgE in bronchial asthma.

METHODS

A commercially available BIAcore 2000 instrument, based on SPR technology, was utilized for assessing serum YKL-40 levels in a control sample size of 45 and active sample size of 97. Antibody immobilization was optimized to obtain the best sensor performance and a sensitive analytic detection. A commercially available ELISA kit was utilized for detecting serum IgE to estimate allergic condition-associated asthma.

RESULTS

The results of SPR technology could distinctly classify with highly statistical significance, the asthma severities by estimating the elevated levels of YKL-40 in blood sera of minute quantities (up to 0.33 ng/ml), and thus differentiates superior utility in comparison with ELISA method. No statistically significant correlation of YKL-40 and IgE was observed.

CONCLUSIONS

Serum YKL-40 may be used as a protein marker in classifying asthma severity by applying SPR technology as a reliable, label-free, highly sensitive, and cost-effective tool.

Genome-wide transcriptome analysis of hypothalamus in rats with inherited stress-induced arterial hypertension

Background

The hypothalamus has an important role in the onset and maintenance of hypertension and stress responses. Rats with inherited stress-induced arterial hypertension (ISIAH), reproducing the human stress-sensitive hypertensive state with predominant involvement of the neuroendocrine hypothalamic-pituitary-adrenal and sympathoadrenal axes, were used for analysis of the hypothalamus transcriptome.

Results

RNA-seq analysis revealed 139 genes differentially expressed in the hypothalami of hypertensive ISIAH and normotensive Wistar Albino Glaxo (WAG) rats. According to the annotation in databases, 18 of the differentially expressed genes (DEGs) were associated with arterial hypertension. The Gene Ontology (GO) functional annotation showed that these genes were related to different biological processes that may contribute to the hypertension development in the ISIAH rats. The most significantly affected processes were the following: regulation of hormone levels, immune system process, regulation of response to stimulus, blood circulation, response to stress, response to hormone stimulus, transport, metabolic processes, and endocrine system development. The most significantly affected metabolic pathways were those associated with the function of the immune system and cell adhesion molecules and the metabolism of retinol and arachidonic acid. Of the top 40 DEGs making the greatest contribution to the interstrain differences, there were 3 genes (Ephx2, Cst3 and Ltbp2) associated with hypertension that were considered to be suitable for further studies as potential targets for the stress-sensitive hypertension therapy. Seven DEGs were found to be common between hypothalamic transcriptomes of ISIAH rats and Schlager mice with established neurogenic hypertension.

Conclusions

The results of this study revealed multiple DEGs and possible mechanisms specifying the hypothalamic function in the hypertensive ISIAH rats. These results provide a basis for further investigation of the signalling mechanisms that affect hypothalamic output related to stress-sensitive hypertension development.

Electronic supplementary material

The online version of this article (doi:10.1186/s12863-015-0307-8) contains supplementary material, which is available to authorized users.

Bortezomib modulates CHIT1 and YKL40 in monocyte-derived osteoclast and in myeloma cells

Osteolytic bone disease is a common manifestation of multiple myeloma (MM) that leads to progressive skeleton destruction and is the most severe cause of morbidity in MM patients. It results from increased osteolytic activity and decrease osteoblastic function. Activation of mammalian chitinases chitotriosidase (CHIT1) and YKL40 is associated with osteoclast (OCs) differentiation and bone digestion. In the current study, we investigated the effect of two Bortezomib’s concentration (2.5 and 5 nM) on osteoclastogenesis by analyzing regulation of chitinase expression. OCs exposition to bortezomib (BO) was able to inhibit the expression of different OCs markers such as RANK, CTSK, TRAP, and MMP9. In addition BO-treatment reduced CHIT1 enzymatic activity and both CHIT1 and YKL40 mRNA expression levels and cytoplasmatic and secreted protein. Moreover, immunofluorescence evaluation of mature OCs showed that BO was able to translocate YKL40 into the nucleus, while CHIT1 remained into the cytoplasm. Since MM cell lines such as U266, SKM-M1 and MM1 showed high levels of CHIT1 activity, we analyzed bone resorption ability of U266 using dentin disk assay resorption pits. Silencing chitinase proteins in U266 cell line with specific small interfering RNA, resulted in pits number reduction on dentine disks. In conclusion, we showed that BO decreases osteoclastogenesis and reduces bone resorption in OCs and U266 cell line by modulating the chitinases CHIT1 and YKL40. These results indicate that chitinases may be a therapeutic target for bone disease in MM patients.

Circulating and Tissue Expression Levels of YKL-40 in Renal Cell Cancer

PURPOSE

Blood levels of YKL-40 are elevated in various malignancies and other inflammatory diseases. Higher YKL-40 levels have consequently been shown to correlate with poor prognosis in several cancers. We investigated the prognostic value of circulating and tissue levels of YKL-40 in renal cell cancer.

MATERIALS AND METHODS

Preoperative YKL-40 serum/plasma levels were determined in 222 surgically treated patients with renal cell cancer and in 35 controls. Postoperative serum samples were analyzed in 19 of the 222 renal cell cancer cases. Gene expression levels were assessed in 101 renal cell cancer frozen tissue samples using quantitative real-time reverse transcriptase-polymerase chain reaction. Finally immunohistochemical analysis was done in 37 renal cell cancer cases to assess tissue localization of YKL-40. Results were correlated with clinicopathological and followup data.

RESULTS

YKL-40 serum but not tissue gene expression levels were higher in patients with renal cell cancer compared to controls (p = 0.050). Serum YKL-40 levels significantly increased following nephrectomy (p <0.001). High circulating YKL-40 concentrations were independently associated with shorter survival in the serum and plasma cohorts. YKL-40 gene expression did not correlate with patient prognosis.

CONCLUSIONS

Preoperatively elevated circulating levels of YKL-40 predict survival in patients treated with nephrectomy for renal cell cancer independently of levels determined in serum or plasma. Tumor cells do not seem to be the main source of increased serum/plasma YKL-40 levels in patients with renal cell cancer.

How to target small cell lung cancer

Small cell lung cancer (SCLC) is a highly malignant disease with dismal prognosis. Although great progress has been made in investigating genetic aberrations and putative drivers of this tumor entity, the mechanisms of rapid dissemination and acquisition of drug resistance are not clear. The majority of SCLC cases are characterized by inactivation of the tumor suppressors p53 and retinoblastoma (Rb) and, therefore, interchangeable drivers will be difficult to target successfully. Access to pure cultures of SCLC circulating tumor cells (CTCs) and study of their tumor biology has revealed a number of new potential targets. Most important, expression of chitinase-3-like-1/YKL-40 (CHI3L1) which controls expression of vascular epithelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP9) was newly described in these cells. The process switching CHI3L1-negative SCLC cells to CHI3L1-positive CTCs seems to be associated with cytokines released by inflammatory immune cells. Furthermore, these CTCs were found to promote monocyte-macrophage differentiation, most likely of the M2 tumor-promoting type, recently described to express PD-1 immune checkpoint antigen in SCLC. In conclusion, dissemination of SCLC seems to be linked to conversion of regular tumor cells to highly invasive CHI3L1-positive CTCs, which are protected by immune system suppression. Besides the classical targets VEGF, MMP-9 and PD-1, CHI3L1 constitutes a new possibly drugable molecule to retard down dissemination of SCLC cells, which may be similarly relevant for glioblastoma and other tumor entities.

CSF neuroinflammatory biomarkers in bipolar disorder are associated with cognitive impairment

Persistent cognitive impairment in the euthymic state of bipolar disorder is increasingly recognized. Mounting evidence also suggests an association between neuroinflammation and cognitive dysfunction. The purpose of this study was to test if cerebrospinal fluid (CSF) markers of neuroinflammation could account for cognitive impairment in bipolar disorder. Hierarchical linear regression models were applied to account for performance in five cognitive domains using CSF neuroinflammatory biomarkers as predictors in patients with bipolar disorder type I and II (N=78). The associations between these biomarkers and cognition were further tested in healthy age- and sex-matched controls (N=86). In patients with bipolar disorder, the CSF biomarkers accounted for a significant proportion of the variance in executive functions (42.8%, p=<.0005) independently of age, medication, disease status, and bipolar subtype. The microglial marker YKL-40 had a high impact (beta=-.99), and was the only biomarker that contributed individually. CSF biomarkers were not associated with cognitive performance in healthy controls. The CSF neuroinflammation biomarker YKL-40 is associated with executive performance in euthymic bipolar disorder, but not in healthy controls.

Identification and function analysis of contrary genes in Dupuytren's contracture

The present study aimed to analyze the expression of genes involved in Dupuytren's contracture (DC), using bioinformatic methods. The profile of GSE21221 was downloaded from the gene expression ominibus, which included six samples, derived from fibroblasts and six healthy control samples, derived from carpal-tunnel fibroblasts. A Distributed Intrusion Detection System was used in order to identify differentially expressed genes. The term contrary genes is proposed. Contrary genes were the genes that exhibited opposite expression patterns in the positive and negative groups, and likely exhibited opposite functions. These were identified using Coexpress software. Gene ontology (GO) function analysis was conducted for the contrary genes. A network of GO terms was constructed using the reduce and visualize gene ontology database. Significantly expressed genes (801) and contrary genes (98) were screened. A significant association was observed between Chitinase-3-like protein 1 and ten genes in the positive gene set. Positive regulation of transcription and the activation of nuclear factor-κB (NF-κB)-inducing kinase activity exhibited the highest degree values in the network of GO terms. In the present study, the expression of genes involved in the development of DC was analyzed, and the concept of contrary genes proposed. The genes identified in the present study are involved in the positive regulation of transcription and activation of NF-κB-inducing kinase activity. The contrary genes and GO terms identified in the present study may potentially be used for DC diagnosis and treatment.

RelB/p50 complexes regulate cytokine-induced YKL-40 expression

The secreted protein, YKL-40, has been proposed as a biomarker of a variety of human diseases characterized by ongoing inflammation, including chronic neurologic pathologies such as multiple sclerosis and Alzheimer's disease. However, inflammatory mediators and the molecular mechanism responsible for enhanced expression of YKL-40 remained elusive. Using several mouse models of inflammation, we now show that YKL-40 expression correlated with increased expression of both IL-1 and IL-6. Furthermore, IL-1 together with IL-6 or the IL-6 family cytokine, oncostatin M, synergistically upregulated YKL-40 expression in both primary human and mouse astrocytes in vitro. The robust cytokine-driven expression of YKL-40 in astrocytes required both STAT3 and NF-κB binding elements of the YKL-40 promoter. In addition, YKL-40 expression was enhanced by constitutively active STAT3 and inhibited by dominant-negative IκBα. Surprisingly, cytokine-driven expression of YKL-40 in astrocytes was independent of the p65 subunit of NF-κB and instead required subunits RelB and p50. Mechanistically, we show that IL-1-induced RelB/p50 complex formation was further promoted by oncostatin M and that these complexes directly bound to the YKL-40 promoter. Moreover, we found that expression of RelB was strongly upregulated during inflammation in vivo and by IL-1 in astrocytes in vitro. We propose that IL-1 and the IL-6 family of cytokines regulate YKL-40 expression during sterile inflammation via both STAT3 and RelB/p50 complexes. These results suggest that IL-1 may regulate the expression of specific anti-inflammatory genes in nonlymphoid tissues via the canonical activation of the RelB/p50 complexes.

Exacerbating factors induce different gene expression profiles in peripheral blood mononuclear cells from asthmatics, patients with chronic obstructive pulmonary disease and healthy subjects

BACKGROUND

Despite several common phenotypic features, chronic obstructive pulmonary disease (COPD) and severe asthma differ with regard to their causative factors and pathophysiology. Both diseases may be exacerbated by environmental factors, however, the molecular profiles of disease episodes have not been comprehensively studied. We identified differences in gene and protein expression profiles expressed by peripheral blood mononuclear cells (PBMC) of COPD patients, patients with atopic asthma and healthy subjects when challenged with exacerbating factors in vitro: lipopolysaccharide (LPS), house dust mite (HDM) and cat allergen.

METHODS

PBMC isolated from patients with severe atopic asthma and COPD, as well as healthy subjects were stimulated with rDer p 1 DG, rFel d 1 DG and LPS. The changes in the expression of 47 genes belonging to five groups (phospholipase A2, eicosanoids, transcription factors, cytokines and airway remodeling) were studied using TaqMan low density array cards. Immunoblotting was used to study relative protein expression.

RESULTS

rDer p 1 significantly up-regulated the expression of PLA2G4A, PLA2G6, PLA2G15, CYSLTR1, LB4R2, PTGS1, PTGS2, FOXP1, GATA3, HDAC2, IREB2, PPARG, STAT4, TSLP and CHI3L1 genes in asthmatics in comparison to healthy subjects. LPS induced significant expression of ANXA1 and LTA4H in asthmatics when compared to COPD patients and healthy subjects. SOX6,STAT4 and IL1RL1 were induced in COPD after LPS stimulation. Analysis of protein expression revealed a pattern similar to mRNA expression.

CONCLUSIONS

LPS-induced exacerbation of asthma and COPD is characterized by differential expression of selected genes in PBMC. HDM allergen changed the expression profile of inflammatory genes between patients with asthma of atopic origin and healthy controls.

Nerve growth factor promotes expression of novel genes in intervertebral disc cells that regulate tissue degradation

Object

Increased neurotrophin activity in degenerative intervertebral discs (IVDs) is one potential cause of chronic low-back pain (LBP). The aim of the study was to assess if nerve growth factor (NGF) might alter gene expression of IVD cells and contribute to disc degeneration by enhancing expression or activity of factors that cause breakdown of IVD matrix.

Methods

Rat-tail IVD cells were stimulated by NGF and subjected to microarray analysis. Real-time polymerase chain reaction, Western blotting, and immunocytochemistry of rat and human IVD cells and tissues treated with NGF in vitro in the absence or presence of the NGF inhibitor Ro 08-2750 were used to confirm findings of the microarray studies. Phosphorylation of mitogen-activated protein kinase (MAPK) was used to identify cell signaling pathways involved in NGF stimulation in the absence or presence of Ro 08-2750.

Results

Microarray analysis demonstrated increased expression of chitinase 3-like 1 (Chi3l1), lipocalin 2 (Lcn2), and matrix metalloproteinase–3 (Mmp3) following NGF stimulation of rat IVD cells in vitro. Increased gene expression was confirmed by real-time polymerase chain reaction with a relative increase in the Mmp/Timp ratio. Increased expression of Chi3l1, Lcn2, and Mmp3 following NGF stimulation was also demonstrated in rat cells and human tissue in vitro. Effects of NGF on protein expression were blocked by an NGF inhibitor and appear to function through the extracellular-regulation kinase 1/2 (ERK1/2) MAPK pathway.

Conclusions

Nerve growth factor has potential effects on matrix turnover activity and influences the catabolic/anabolic balance of IVD cells in an adverse way that may potentiate IVD degeneration. Anti-NGF treatment might be beneficial to ameliorate progressive tissue breakdown in IVD degeneration and may lead to pain relief.

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.

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.

Chitinase 3-like 1 synergistically activates IL6-mediated STAT3 phosphorylation in intestinal epithelial cells in murine models of infectious colitis

BACKGROUND

Chitinase 3-like 1 (CHI3L1) is an inducible molecule on intestinal epithelial cells during the development of inflammatory bowel disease.

METHODS

To investigate the role of CHI3L1 in bacterial infectious colitis, we orally inoculated pathogenic Salmonella typhimurium and potentially pathogenic adherent-invasive Escherichia coli (AIEC) LF82 virulent strain into C57Bl/6 wild-type mice or CHI3L1 knockout (KO) mice.

RESULTS

Both S. typhimurium and AIEC LF82 were found to efficiently induce severe intestinal inflammation in wild-type mice but not in CHI3L1 KO mice. These bacteria-infected CHI3L1 KO mice exhibit decreased cellular infiltration, bacterial translocation, and production of interleukin (IL)-6 and IL-22, as compared with those of wild-type mice. More importantly, CHI3L1 KO mice displayed aberrant STAT3 activation after bacterial infections. Co-stimulation of CHI3L1 and IL-6, but not IL-22, synergistically activates STAT3 signaling pathway in intestinal epithelial cells in an NF-κB/MAPK-dependent manner.

CONCLUSIONS

CHI3L1 promotes the onset of selected gram-negative bacterial infectious colitis through IL-6/STAT3 pathway.

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.

Brain barriers and a subpopulation of astroglial progenitors of developing human forebrain are immunostained for the glycoprotein YKL-40

YKL-40, a glycoprotein involved in cell differentiation, has been associated with neurodevelopmental disorders, angiogenesis, neuroinflammation and glioblastomas. We evaluated YKL-40 protein distribution in the early human forebrain using double-labeling immunofluorescence and immunohistochemistry. Immunoreactivity was detected in neuroepithelial cells, radial glial end feet, leptomeningeal cells and choroid plexus epithelial cells. The subpial marginal zone was YKL-40-positive, particularly in the hippocampus, from an early beginning stage in its development. Blood vessels in the intermediate and subventricular zones showed specific YKL-40 reactivity confined to pericytes. Furthermore, a population of YKL-40-positive, small, rounded cells was identified in the ventricular and subventricular zones. Real-time quantitative RT-PCR analysis showed strong YKL-40 mRNA expression in the leptomeninges and the choroid plexuses, and weaker expression in the telencephalic wall. Immunohistochemistry revealed a differential distribution of YKL-40 across the zones of the developing telencephalic wall. We show that YKL-40 is associated with sites of the brain barrier systems and propose that it is involved in controlling local angiogenesis and access of peripheral cells to the forebrain via secretion from leptomeningeal cells, choroid plexus epithelium and pericytes. Furthermore, we suggest that the small, rounded, YKL-40-positive cells represent a subpopulation of astroglial progenitors, and that YKL-40 could be involved in the differentiation of a particular astrocytic lineage.

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.