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Osteomyelitis is a debilitating infectious disease of the bone which is predominantly caused by Staphylococcus aureus (S. aureus). MicroRNAs (miRNAs) have been shown to play a regulatory role in osteogenesis. In the present study, the expression levels of miRNAs proposed to potentially play a regulatory role in bone formation or differentiation (miR-24, miR-29b, miR-200a, miR-208, miR-322) were analyzed in the whole blood of patients with bacterial osteomyelitis or healthy controls, and in MC3T3-E1 cells infected with S. aureus by qRT-PCR. The expression of miR-24 was significantly down-regulated in osteomyelitis patients and S. aureus-infected MC3T3-E1 cells compared with the healthy controls or untreated control cells. Moreover, our results showed that S. aureus inhibited MC3T3-E1 cell proliferation, induced osteoblast apoptosis and prohibited bone formation and mineralization. We found that overexpression of miR-24 could reduce the effects of S. aureus, while inhibition of miR-24 intensified the effects. We also demonstrated that miR-24 suppressed the expression of chitinase 3-like 1 (CHI3L1) mRNA, thought to mediate multiple signaling pathways, by directly binding to the 3'-untranslated region., (© 2015 Wiley Periodicals, Inc.)

Chitinase 3-like 1 (CHI3L1) has been proposed as a biomarker associated with the conversion to clinically definite multiple sclerosis in patients with clinically isolated syndromes, based on the finding of increased cerebrospinal fluid CHI3L1 levels in clinically isolated syndrome patients who later converted to multiple sclerosis compared to those who remained as clinically isolated syndrome. Here, we aimed to validate CHI3L1 as a prognostic biomarker in a large cohort of patients with clinically isolated syndrome. This is a longitudinal cohort study of clinically isolated syndrome patients with clinical, magnetic resonance imaging, and cerebrospinal fluid data prospectively acquired. A total of 813 cerebrospinal fluid samples from patients with clinically isolated syndrome were recruited from 15 European multiple sclerosis centres. Cerebrospinal fluid CHI3L1 levels were measured by enzyme-linked immunosorbent assay. Multivariable Cox regression models were used to investigate the association between cerebrospinal fluid CHI3L1 levels and time to conversion to multiple sclerosis and time to reach Expanded Disability Status Scale 3.0. CHI3L1 levels were higher in patients who converted to clinically definite multiple sclerosis compared to patients who continued as clinically isolated syndrome (P = 8.1 × 10(-11)). In the Cox regression analysis, CHI3L1 levels were a risk factor for conversion to multiple sclerosis (hazard ratio = 1.7; P = 1.1 × 10(-5) using Poser criteria; hazard ratio = 1.6; P = 3.7 × 10(-6) for McDonald criteria) independent of other covariates such as brain magnetic resonance imaging abnormalities and presence of cerebrospinal fluid oligoclonal bands, and were the only significant independent risk factor associated with the development of disability (hazard ratio = 3.8; P = 2.5 × 10(-8)). High CHI3L1 levels were associated with shorter time to multiple sclerosis (P = 3.2 × 10(-9) using Poser criteria; P = 5.6 × 10(-11) for McDonald criteria) and more rapid development of disability (P = 1.8 × 10(-10)). These findings validate cerebrospinal fluid CHI3L1 as a biomarker associated with the conversion to multiple sclerosis and development of disability and reinforce the prognostic role of CHI3L1 in patients with clinically isolated syndrome. We propose that determining cerebrospinal fluid chitinase 3-like 1 levels at the time of a clinically isolated syndrome event will help identify those patients with worse disease prognosis., (© The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Increasing evidence demonstrated that chitinase 3-like 1 (CHI3L1) was highly expressed and tightly associated with human tumor development and progression. However, its precise role in non-small cell lung cancer (NSCLC) remains to be delineated. The aim of this study was to examine CHI3L1 expression in patients with NSCLC and explore the relationship of CHI3L1 protein with clinicopathologic factors, tumor angiogenesis, and prognosis. CHI3L1 protein and intratumoral microvessels were examined by immunohistochemical staining in 95 NSCLC patients. Intratumoral microvessel density (MVD) was measured by counting CD34-positive immunostained endothelial cells. Quantitative real-time PCR (qRT-PCR) analyses were used to investigate the CHI3L1 expression status in tissues. Our result showed that CHI3L1 was significantly up-regulated in NSCLC tissues. In addition, univariate and multivariate analysis demonstrated that CHI3L1 protein overexpression and high MVD were significantly associated with tumor relapse. Although CHI3L1 overexpression and high MVD indicated poor overall survival (P < 0.05), multivariate analysis suggested that only CHI3L1 overexpression was an independent prognostic marker for unfavorable overall survival in patients with NSCLC (P < 0.05). The current results demonstrated that CHI3L1 may be a promising biomarker to identify individuals with poor prognostic potential and a possible target for anti-angiogenic therapy in patients with early stage NSCLC.

Glioblastoma multiforme (GBM), a highly aggressive brain cancer characterized by uncontrolled proliferation, resistance to cell death, angiogenesis, and vascular edema, remains one of the deadliest types of cancer. The subventricular zone (SVZ) harbors cells with great proliferative potential, and the microenvironment within the SVZ is permissive to growth and proliferation. This neurogenic niche is suspected to be a vulnerable site for the origin of subtypes of GBM. The aim of our study was to determine the immunohistochemical expression of mIDH1 and YKL40 in relationship to the SVZ of GBMs. YKL40, also known as chitinase-like protein 1, is included as a mesenchymal marker and associated with a poor prognosis. The protein is a secreted inflammatory molecule with no chitinolytic activity. However, the mutation of IDH1 (mIDH1) has been found in the cytoplasm and peroxisomes of 70-80% of secondary GBMs. In our study we found that YKL40-positive GBM is significantly linked to SVZ types IV and V (p < 0.0001). Our results show the diversity among GBMs related to the SVZ, which should be considered in the design of future targeted therapies. There was a significant impact of patient age, mIDH1 positivity, SVZ type III, and chemoradiotherapy on overall survival.

Background: Severe and fatal malaria are associated with dysregulated host inflammatory responses to infection. Chitinase 3-like 1 (CHI3L1) is a secreted glycoprotein implicated in regulating immune responses. Expression and function of CHI3L1 in malaria infection were investigated., Methods: Plasma levels of CHI3L1 were quantified in a case-control study of Ugandan children presenting with Plasmodium falciparum malaria. CHI3L1 levels were compared in children with uncomplicated malaria (UM; n = 53), severe malarial anaemia (SMA; n = 59) and cerebral malaria (CM; n = 44) using the Kruskall Wallis-test, and evaluated for utility in predicting fatal (n = 23) versus non-fatal (n = 80) outcomes in severe disease using the Mann Whitney U test, receiver operating characteristic curves, and combinatorial analysis. Co-culture of P. falciparum with human peripheral blood mononuclear cells and the Plasmodium berghei ANKA experimental model of cerebral malaria were used to examine the role of CHI3L1 in severe malaria., Results: In children presenting with falciparum malaria, CHI3L1 levels were increased in SMA and CM versus UM (p < 0.001). Among severe malaria cases, CHI3L1 levels at presentation predicted subsequent death (area under receiver operating characteristic curve 0.84 [95% CI 0.76-0.92]) and in combination with other host biomarkers, predicted mortality with high sensitivity (100% [85.7-100]) and specificity (81.3% [71.3-88.3]). Plasmodium falciparum stimulated CHI3L1 production by human peripheral blood mononuclear cells in vitro. CHI3L1 was increased in plasma and brain tissue in experimental cerebral malaria, but targeted Chi3l1 deletion did not alter cytokine production or survival in this model., Conclusions: These data suggest that plasma CHI3L1 measured at presentation correlates with malaria severity and predicts outcome in paediatric SMA and CM, but do not support a causal role for CHI3L1 in cerebral malaria pathobiology in the model tested.

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., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Malignant gliomas are the most common type of primary malignant brain tumours, characterized by extreme proliferation and aggressive invasion. There is evidence for over-expression of the YKL40 gene in high-grade gliomas. The high serum levels of the glycoprotein are associated with poor prognosis of various inflammatory and tumour processes. We investigated the YKL40 mRNA level and protein expression in the tumour site and in the serum of high-grade glioma patients. The YKL-40 expression in 36 patients with glial tumours (astrocytoma grade III, glioblastoma) and 33 age-matched healthy persons was measured by gene analysis, immunohistochemistry and ELISA. YKL-40 serum levels in high-grade glioma patients compared to healthy subjects were significantly increased (P ≤ 0.05). A wide range of variability in YKL40 mRNA expression was found. YKL-40 staining in situ was more abundant in glioblastoma tissue than in anaplastic astrocytoma, with the lowest level in normal brain tissue. Our gene analysis revealed that in general, YKL40 mRNA in glioma patients was over-expressed versus normal brain. A significant correlation between YKL40 transcript and protein levels was observed (P ≤ 0.05). It could be speculated that the YKL-40 protein might contribute to glioblastomas' specific biological characteristics that distinguish them from grade III gliomas. A complex investigation of YKL40 expression was performed at the molecular and cellular levels in human high-grade gliomas. Serum YKL-40 concentrations increased with tumour grade and correlated positively with transcript rate, being the highest in glioblastoma. We provide evidence for a relationship between YKL40 expression and the malignancy of glial tumours.

Chitinase 3-like protein 1 (CHI3L-1) and chitotriosidase (CHIT-1) are members of the chitinase family. CHI3L-1 is a newly recognized protein that is secreted by activated macrophages and neutrophils and expressed in a broad spectrum of inflammatory conditions and cancers. In human plasma, CHIT-1 activity has been proposed as a biochemical marker of macrophage activation. Although CHI3L-1 expression in inflammation is under examination, little is known regarding its regulation during macrophages' full maturation and polarization. In this study, we compared CHI3L-1 and CHIT-1 modulation during monocyte to macrophage transition and polarization. Gene expression analysis was investigated by real-time PCR. We found that during the maturation of monocytes into macrophages, the expression of both CHI3L-1 and CHIT-1 increased exponentially over time. Additionally, we observed a different regulation of CHI3L-1 and CHIT-1 in undifferentiated monocytes under stimulation with lipopolysaccharide, interferon-γ, and interleukin-4, at the same concentration used to polarize macrophages. Our finding suggests that in the immune response, the role of CHI3L-1 and CHIT-1 is not restricted to innate immunity, but they are also protagonists in acquired immunity.

Numerous inflammatory conditions are associated with elevated YKL-40 expression by infiltrating macrophages. Thus, we were surprised to observe minimal macrophage and abundant astrocyte expression of YKL-40 in neuroinflammatory conditions. The aims of the current study were to better delineate this discrepancy, characterize the factors that regulate YKL-40 expression in macrophages and astrocytes and study whether YKL-40 expression correlates with cell morphology and/or activation state. In vitro, macrophages expressed high levels of YKL-40 that was induced by classical activation and inhibited by alternative activation. Cytokines released from macrophages induced YKL-40 transcription in astrocytes that was accompanied by morphological changes and altered astrocytic motility. Because coculturing of astrocytes and macrophages did not reverse this in vitro expression pattern, additional components of the in vivo central nervous system (CNS) milieu must be required to suppress macrophage and induce astrocyte expression of YKL-40., (© 2011 The Authors; Brain Pathology © 2011 International Society of Neuropathology.)

The Ras signaling pathway, consisting of mitogen-activated protein kinase (MAPK) and PI3K/AKT signaling, is a prominent oncogenic pathways in adult diffuse gliomas, but few studies have evaluated such pathways in pediatric malignant gliomas. We investigated by immunohistochemistry MAPK and AKT signaling in a series of 28 pediatric high-grade gliomas (WHO grade III and IV). We sought a possible association of phospho-ERK (p-ERK) and phospho-AKT (p-AKT) with expression of other proteins involved in the Ras pathway, that is, YKL40, epidermal growth factor receptor (EGFR), EGFR vIII and c-Met. Moreover we correlated the expression of p-ERK and p-AKT with prognosis. No cases showed expression for c-Met and EGFR, and only one case was positive for EGFR vIII. YKL-40 protein was expressed in 43% of cases. We detected expression of p-ERK and p-AKT in 61% and 57%, respectively, of pediatric high grade gliomas. Statistical analysis comparing the two groups in term of high and low p-ERK and p-AKT expression showed a trend toward worse overall survival in patients with high expression of p-AKT. The activation of ERK and AKT suggest a possible role of this protein in inducing activation of the Ras signaling pathway in pediatric high-grade gliomas. Moreover high levels of p-AKT are associated with worse overall survival., (© 2011 Japanese Society of Neuropathology.)

Background: YKL-40 is a new biomarker with diagnostic value in many different cancers. Whether it may serve as a biomarker for hepatocellular carcinoma (HCC) is still unclear. This study aimed to examine the expression of YKL-40 in the serum and liver tissues of HCC patients and in HCC cell lines, in comparison with that in non-HCC liver disease patients and non-tumor hepatic cell lines, respectively., Methods: Immunohistochemical staining was used to detect YKL-40 protein expression in liver biopsy specimens from 8 HCC patients. ELISA was used to assess the serum YKL-40 level in 90 HCC patients, 90 inactive HBsAg carrier (IHC) patients with normal liver functions, and 90 liver cirrhosis patients. Real-time PCR was used to determine the YKL-40 mRNA expression in three HCC cell lines and two non-tumor hepatic cell lines., Results: Immunohistochemical staining of liver biopsy specimens from HCC patients showed that the YKL-40 protein expression in tumor tissue was higher than that in adjacent normal tissues. ELISA revealed that the YKL-40 serum level in the HCC group was significantly higher than that in the IHC group, but not significantly different from that in the cirrhosis group. Real-time PCR showed that YKL-40 mRNA levels in HCC cell lines were significantly higher than those in non-tumor hepatic cells., Conclusions: YKL-40 is highly expressed in HCC at the molecular, cellular and tissue levels. However, it may not serve as a serum biomarker for HCC because measurement of the serum YKL-40 level cannot distinguish HCC from cirrhosis.

Nuclear factor I-X3 (NFI-X3) is a newly identified splice variant of NFI-X that regulates expression of several astrocyte-specific markers, such as glial fibrillary acidic protein. Here, we identified a set of genes regulated by NFI-X3 that includes a gene encoding a secreted glycoprotein YKL-40. Although YKL-40 expression is up-regulated in glioblastoma multiforme, its regulation and functions in nontransformed cells of the central nervous system are widely unexplored. We find that expression of YKL-40 is activated during brain development and also differentiation of neural progenitors into astrocytes in vitro. Furthermore, YKL-40 is a migration factor for primary astrocytes, and its expression is controlled by both NFI-X3 and STAT3, which are known regulators of gliogenesis. Knockdown of NFI-X3 and STAT3 significantly reduced YKL-40 expression in astrocytes, whereas overexpression of NFI-X3 dramatically enhanced YKL-40 expression in glioma cells. Activation of STAT3 by oncostatin M induced YKL-40 expression in astrocytes, whereas expression of a dominant-negative STAT3 had a suppressive effect. Mechanistically, NFI-X3 and STAT3 form a complex that binds to weak regulatory elements in the YKL-40 promoter and activates transcription. We propose that NFI-X3 and STAT3 control the migration of differentiating astrocytes as well as migration and invasion of glioma cells via regulating YKL-40 expression.