YKL-40 Protein Research Articles

Blood DNA methylomic signatures associated with CSF biomarkers of Alzheimer's disease in the EMIF-AD study.

We investigated blood DNA methylation patterns associated with 15 well-established cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) pathophysiology, neuroinflammation, and neurodegeneration. We assessed DNA methylation in 885 blood samples from the European Medical Information Framework for Alzheimer's Disease (EMIF-AD) study using the EPIC array. We identified Bonferroni-significant differential methylation associated with CSF YKL-40 (five loci) and neurofilament light chain (NfL; seven loci) levels, with two of the loci associated with CSF YKL-40 levels correlating with plasma YKL-40 levels. A co-localization analysis showed shared genetic variants underlying YKL-40 DNA methylation and CSF protein levels, with evidence that DNA methylation mediates the association between genotype and protein levels. Weighted gene correlation network analysis identified two modules of co-methylated loci correlated with several amyloid measures and enriched in pathways associated with lipoproteins and development. We conducted the most comprehensive epigenome-wide association study (EWAS) of AD-relevant CSF biomarkers to date. Future work should explore the relationship between YKL-40 genotype, DNA methylation, and protein levels in the brain. Blood DNA methylation was assessed in the EMIF-AD MBD study. Epigenome-wide association studies (EWASs) were performed for 15 Alzheimer's disease (AD)-relevant cerebrospinal fluid (CSF) biomarker measures. Five Bonferroni-significant loci were associated with YKL-40 levels and seven with neurofilament light chain (NfL). DNA methylation in YKL-40 co-localized with previously reported genetic variation. DNA methylation potentially mediates the effect ofsingle-nucleotide polymorphisms (SNPs) in YKL-40 on CSF protein levels.

Prognostic and predictive role of YKL-40 in anal squamous cell carcinoma: a serological and tissue-based analysis in a multicentric cohort.

Anal squamous cell carcinoma (ASC) is a rare gastrointestinal malignancy showing an increased incidence over the past decades. YKL-40 is an immune modulator and pro-angiogenetic factor that showed a promising prognostic and predictive potential in several malignancies, but limited data are available for ASC. This study aims to provide an extensive evaluation of the prognostic and predictive role of YKL-40 in a multicenter cohort of ASC patients. We retrospectively retrieved 72 consecutive cases of ASC diagnosed between February 2011 and March 2021. Both serum and tissue protein expression of YKL-40 were assessed, the latter in ASC tumor cells and peritumor immune cells. Increased YKL-40 serum levels at the time of diagnosis were associated with older age (p = 0.035), presence of cardiovascular/metabolic comorbidities (p = 0.007), and death for any cause (p = 0.011). In addition, high serum levels of YKL-40 were associated with a poor prognosis (HR: 2.82, 95% CI: 1.01-7.84; p = 0.047). Protein expression of YKL-40 in ASC tumor cells was significantly associated with low tumor grade (p = 0.031), while the increased expression in peritumor immune cells was associated with a worse response of patients to chemoradiotherapy (p = 0.007). However, YKL-40 protein expression in ASC tumor cells or peritumor immune cells did not significantly impact patient overall survival. In conclusion, YKL-40 resulted a relevant prognostic (serum level) and predictive (tissue protein expression in peritumor immune cells) biomarker and can considerably improve ASC patient clinical management.

YKL-40 Knockdown Decreases Oxidative Stress Damage in Ovarian Granulosa Cells.

Background: Oxidative stress has been implicated in the pathogenesis of polycystic ovarian syndrome (PCOS). To develop novel antioxidant drugs, it is necessary to explore the key regulatory molecules involved in oxidative stress in PCOS. Plasma YKL-40 levels are elevated in patients with PCOS; however, its role remains unclear. Methods: The follicular fluids of 20 women with PCOS and 12 control subjects with normal ovarian function were collected, and YKL-40 in follicular fluids was measured by enzyme-linked immunosorbent assay. A letrozole-induced PCOS rat model was established and the expression level of YKL-40 in the ovaries was detected by immunohistochemistry. KGN cells were treated with H2O2 to generate an ovarian granulosa cell (OGC) model of oxidative stress. The siRNA was transfected into the cells for knockdown. The effect of YKL-40 knockdown on H2O2-treated KGN cells was evaluated by measuring proliferation, apoptosis, activities of T-SOD, GSH-Px, and CAT, levels of MDA, IL-1β, IL-6, IL-8, and TNF-α, and the PI3K/AKT/NF-κB signaling pathway. Results: YKL-40 levels were elevated in the follicular fluids of women with PCOS compared with control subjects with normal ovarian function. The expression level of YKL-40 in the ovaries of rats with PCOS is obviously higher than that in the ovaries of the control group rats. H2O2 treatment enhanced YKL-40 mRNA expression and protein secretion. YKL-40 knockdown enhanced cell proliferation and antioxidant capacity while decreasing apoptosis and inflammatory factor levels in KGN cells following H2O2 treatment. The knockdown activated the PI3K/AKT signaling pathway and suppressed NF-κB nuclear translocation from the cytoplasm. Conclusion: YKL-40 levels were elevated in the follicular fluids of women with PCOS and the ovaries of rats with PCOS. YKL-40 expression can be induced by oxidative stress, and YKL-40 knockdown can decrease oxidative stress damage in OGCs.

Intracellular Accumulation and Secretion of YKL-40 (CHI3L1) in the Course of DMSO-Induced HL-60 Cell Differentiation.

YKL-40 (CHI3L1) is a matrix glycoprotein stored in human neutrophil-specific granules and released upon activation. While it is implicated in inflammation, cancer progression, and cell differentiation, its exact physiological role remains unclear. This study investigated the intracellular expression and secretion of YKL-40 by untreated and DMSO-treated HL-60 cells in association with surface expression of CD11b and CD66b throughout the differentiation process (up to 120 h). Secreted YKL-40 protein and mRNA levels of YKL-40, CD66b, and CD11b were measured by ELISA and quantitative RT-PCR, respectively. The intracellular YKL-40 and surface CD11b and CD66b expression were assessed by flow cytometry. A significant increase in CD11b expression confirmed DMSO-induced differentiation of HL-60 cells. Upon DMSO stimulation, YKL-40 mRNA expression increased in a time-dependent manner, unlike CD66b. The lack of CD66b (a granulocyte maturation and activation marker) on the surface of HL-60 cells might suggest that DMSO treatment did not induce full maturation or activation. The intracellular YKL-40 protein expression was increasing up to 96 h of DMSO treatment and then declined. YKL-40 secretion into the culture medium was detectable only at later time points (96 and 120 h), which was correlated with a decreased proliferation of DMSO-treated HL-60 cells. These findings suggest sequential changes in YKL-40 production and secretion during DMSO-induced differentiation of HL-60 cells and might contribute to a better understanding of YKL-40's involvement in both physiological processes and disease development, including multiple sclerosis.

Abstract 7628: Pharmacodynamic biomarkers for Rac and Cdc42 inhibitor efficacy

Abstract Metastatic disease drastically reduces clinical prognosis, and remains the primary cause of mortality from solid cancers, such as breast and pancreatic cancer. Since targeted therapeutic options are limited, we developed small molecule compounds to block activation (GTP loading) of the Rho GTPases Rac and Cdc42. Rac and Cdc42 are ideal molecular targets due to their regulation of cell migration, proliferation, invasion, and signaling in cancer and immunosuppressive cells in the tumor microenvironment. Our lead compound MBQ-167 is a dual Rac and Cdc42 inhibitor with IC50 of ~100 nM for inhibition of Rac/Cdc42 activation and the phosphorylation of their common downstream effector p21-activated kinase (PAK). MBQ-167 is highly effective in mouse models of breast cancer metastasis and is currently undergoing a Phase I clinical trial in advanced breast cancer patients. The purpose of this study is to investigate potential target molecules that can be used as biomarkers predictive of Rac/Cdc42 inhibitor efficacy. We recently published that in addition to inhibiting the growth and migration of breast and pancreatic cancer cells, MBQ-167 inhibits macrophage cell migration, immunosuppressive myeloid cell activation and release of interleukin-6 (IL-6), a pro-inflammatory cytokine associated with cancer. Transcriptomic data of tumors from mice treated with vehicle or MBQ-167 identified a number of immunomodulatory pathways downregulated by MBQ-167, including IL-6 and S100A family signaling, and Chitinase 3-like (CHI3L1/CHI4L1) genes coding for the human YKL-40 protein. We tested for the activation status of PAK (phospho (p)-PAK) as a diagnostic marker for Rac/Cdc42 inhibitor efficacy using breast cancer patient tissue in ex vivo culture treated with vehicle or MBQ-167 and found decreased p-PAK staining following immunohistochemistry of MBQ-167-treated tissue. From flow cytometry, using Alexa-488-tagged anti p-PAK antibody, we found that p-PAK was reduced from peripheral blood mononuclear cells (PBMCs) following MBQ-167. ELISA assays for YKL-40/CHI3L1 proteins after treatment of pancreatic cancer cell lines and macrophage-like cells with Rac/Cdc42 inhibitors show that MBQ-167 and the derivative MBQ-168 reduced CHI3L1 levels from conditioned media. These results demonstrate the potential of p-PAK and YKL-40/CHI3L1 from blood as biomarkers for Rac/Cdc42 inhibitor efficacy. This study impacts pharmacodynamic biomarker design for the planned Phase 2 clinical trials for MBQ-167 in breast and pancreatic cancer. Citation Format: Anamaris Torres-Sanchez, Ailed M. Cruz-Collazo, Michael Rivera-Robles, Olga Katsara, Stephanie Dorta-Estremera, Viviana Negron, Victor P. Carlo, Robert J. Schneider, Suranganie Dharmawardhane. Pharmacodynamic biomarkers for Rac and Cdc42 inhibitor efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7628.

Increased Circulating Levels of YKL-40 Protein in Children and Adolescents with Hemophilia: Correlation with the Degree of Hemophilic Arthropathy

Introduction: Hemophilia A and B are rare X-linked inherited bleeding disorders caused by complete or partial deficiency of coagulation factors VIII and IX, respectively. Recurrent joint bleeding (hemarthrosis) is the most frequent clinical manifestation of severe hemophilia. Unless appropriately managed, even subclinical hemarthrosis can lead to hemophilic arthropathy, that severely affects the quality of life of patients. Chitinase-3-like protein 1 (CHI3L1), also known as YKL-40, is a 40-kDa heparin-human cartilage glycoprotein without enzymatic activity, that is encoded by the CHI3L1 gene in humans and its name derives from the one letter code for the three terminal amino acids - tyrosine (Y), lysine (K) and leucine (L). YKL-40 is secreted in vitro and in vivo in the arthritic joint by various cell types, such as activated macrophages, chondrocytes, synoviocytes and neutrophils. Actually, it is a major protein that has been identified in the chondrocytes from arthritic knee joints.In fact, synovial as well as serum YKL-40 levels are found increased in joint diseases like rheumatoid arthritis and osteoarthritis, indicating its potential role as a biomarker of inflammation and tissue remodeling or degradation, whereas it is absent in normal joints. In our knowledge, there are not any reports linking YKL-40 expression with hemophilic arthropathy, thus we aimed to investigate if this protein could be implicated in hemophilic arthropathy severity, by measuring its circulating levels and correlate them with hemophilic arthropathy features and laboratory parameters in children and adolescents with hemophilia A and B. Patients and Methods: Eighty children and adolescents (median age:14 years, range 10-18 years) with severe (n= 60), moderate (n= 8) and mild (n= 12) hemophilia A or B (n= 7), on prophylaxis or on demand treatment (n= 12) were included in the study, while 35 apparently healthy male individuals matched for age served as controls. No signs of hemophilic arthropathy (NHAP), i.e. Hemophilia Joint Health Score 2.1 ≤ 2 and Hemophilia Early Detection Arthropathy with Ultrasound Score ≤ 1, were detected in 34/80 patients with median age of 13.5 years. In 37/80 patients with median age of 14.25 years arthropathy (HAP) was confirmed, while 18/80 patients with median age of 15.75 years presented with acute bleeding (AB)-hemarthrosis or muscle bleed- at the time of the laboratory evaluation. In patients and controls YKL-40 concentrations were determined by means of an immunoenzymatic technique. Results: We found that: a) Circulating YKL-40 levels in patients with hemophilia were significantly higher compared to controls, 21.9±2.3 ng/mL (95% Confidence Intervals of the mean (CI): 19.6;24.2 ng/mL) vs 17.0±2.5 ng/mL (CI: 14.5;19.4 ng/mL), respectively, p=0.003. b) Patients with arthropathy (HAP) tend to express higher circulating YKL-40 levels (25.5±2.0 ng/mL) than patients without arthropathy (NHAP)(20.1±1.8 ng/mL) and patients with acute bleeding (AB) (19.7±2.4 ng/mL), respectively, p-trend=0.06. Conclusions: To the best of our knowledge, this is the first study to evaluate the potential clinical significance of circulating YKL-40 levels in patients with hemophilia and demonstrated that it could reflect hemophilic arthropathy activity in clinical or even in subclinical level. As YKL-40 in synovial fluid is derived from cells in the inflamed/damaged synovium, such as chondrocytes, we postulate that it may be involved in the pathophysiology of the hemophilic arthropathy processes and reflect local disease activity. Further studies are essential on the role of YKL-40 in the evolution of hemophilic arthropathy, in order to fully elucidate its clinical significance and prognostic utility.

YKL-40 and the Cellular Metabolic Profile in Parkinson's Disease.

Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide. A growing body of evidence suggests that mitochondrial dysfunction and inflammation play a crucial role as a pathogenetic mechanism in PD. The glycoprotein YKL-40 (CHI3L1) is a potential biomarker involved in inflammation and tumor processes. The aim of the present study was to investigate the metabolic profile of PBMCs from PD patients and to search for a possible relationship between cellular bioenergetics and YKL-40. The study included 18 naïve PD patients and an age-matched control group (HC, n = 7). Patients were diagnosed according to the MDS-PD, the UPDRS, and the Hoen-Yahr scales. Mitochondrial activity was measured by a metabolic analyzer on isolated PBMCs from PD patients. Gene (qPCR) and protein (ELISA) expression levels of YKL40 were investigated. New data are reported revealing changes in the mitochondrial activity and YKL-40 levels in PD patients. Bioenergetic parameters showed increased respiratory reserve capacity in PD compared to HC. The protein levels of YKL-40 were threefold higher in PD. We found a correlation between the YKL-40 protein levels and basal respiration and between YKL-40 and ATP production. These observations suggest an interplay between YKL-40 and mitochondrial function in PD. We assume that the YKL-40 gene and protein levels in combination with changes in mitochondrial function might serve as an additional tool to monitor the clinical course of PD.

Thrombocytopenia Associated with Myelofibrosis Is Characterized By a Reduced Proportion of Megakaryocyte (MK) Biased Hematopoietic Stem Cells, Defects in MK Maturation and Increased Levels of Pro-Inflammatory Cytokines

The clinical course of patients with advanced forms of myelofibrosis (MF) can frequently be punctuated by thrombocytopenia. Marrow biopsies from these MF patients uniformly reveal megakaryocytic (MK) hyperplasia and dysplasia irrespective of the patient's platelet count. We have performed studies to better understand the origins of MF associated thrombocytopenia. We first examined the expression of G6b-B (MK-lineage specific immunoreceptor tyrosine-based inhibition motif) which is essential in promoting MK maturation, normal platelet release, platelet size and function (Becker. Blood Adv 2022). Recent reports have indicated that genetic deletion in G6b-B and loss-of-function mutations in both murine models and man lead to severe macro-thrombocytopenia and increased bone marrow fibrosis (Becker. Blood Adv 2022; Hofmann. Blood 2018; Melhem. Eur J Hematol 2017), indicating a possible role for this receptor in the development of thrombocytopenia in MF patients. We generated populations of MKs from mononuclear cells or CD34 + from thrombocytopenic or non-thrombocytopenic MFs and healthy donors (HDs) using a two-step culture system as previously described (Mosoyan. Leukemia 2017). A progressive increase of MK maturation (CD41 +CD42 +) was observed in HDs (28.5%±7) and non-thrombocytopenic MFs (32%±13.6) with a concomitant increase of total G6B expression 27%±9 and 38%±14 respectively. By contrast, MKs generated from thrombocytopenic MFs patient cells had limited CD41 +CD42 + (7%±5) and G6B (8.7%±4.7) expression (p<0.05). In addition, morphological analysis revealed that MKs from thrombocytopenic MF patients were small with hypolobulated nuclei while the MKs generated from HDs and non-thrombocytopenic MFs were larger and contained greater numbers of lobes ( Figure 1A). Psaila and coworkers have previously reported that MF is characterized by MK biased hematopoietic stem cells (HSCs) identified by increased expression of G6B (Psaila. Mol Cell 2020). We, however, determined that a reduced proportion of CD34 +CD38 - HSCs from thrombocytopenic patients expressed G6B as compared to non-thrombocytopenic MF or HD CD34 +CD38 - cells (p<0.05) ( Figure 1B). These studies indicate a reduced proportion of MK biased HSCs in thrombocytopenic MFs which likely leads to impaired MKs maturation. We next explored if the MF associated pro-inflammatory milieu also contributes to the MF MK maturation block. Thrombocytopenic MF plasma contained higher levels of YKL-40 (chitinase-3-like-1 protein), TNFα and TPO than HD plasma. For instance, MF plasma was characterized by higher levels of YKL-40 (median141,321 pg/mL) in comparison to HDs (median 19,380 pg/mL). Furthermore, YKL-40 levels were significantly higher in thrombocytopenic (median 187,696 pg/mL; p<0.05) than non-thrombocytopenic (median 78,082 pg/mL) MFs. In addition, TNFα and TPO plasma levels were also significantly higher in plasma from thrombocytopenic than non-thrombocytopenic MFs (p<0.05). We also observed that addition of either rYKL40 or rTNFα to HD-MK cultures resulted in delayed MK maturation as assessed by a reduced proportion of cells expressing CD41 +CD42 + (from 30% to 16.5% and 6.5% respectively) and G6B (from 35.5% to 22.5% and 9.5% respectively). We have previously reported that the treatment of MFs with a protein trap for TGFβ1 led to increases in platelet numbers (Mascarenhas. Clin Cancer Res 2023). The plasma from these patients prior to treatment not only had elevated levels of TGFβ1 (median 6433,917 pg/mL) but also YKL40 (median 275,640 pg/mL). Treatment of the patients with the TGFβ protein trap reduced both TGFβ1 (median 608,087 pg/mL) and YKL-40 (median 160,733 pg/mL) plasma levels, suggesting a regulatory loop between YKL-40 and TGFβ. We further explored this loop by treating the JAK2V617F+ HEL cell line with rYKL-40 in combination with rTGFβ1, which resulted in greater expression of YKL-40 (1.6 FI) than treated cells with rYKL-40 alone. In addition, treatment of HEL cells with a pan TGFβ inhibitor reduced YKL-40 protein expression (1.55 to 0.38). These data suggest the existence of an interplay between YKL40 and TGFβ on MF-MK maturation. Overall, these experiments indicate that thrombocytopenia in MF patients is due to intrinsic abnormalities in G6B originating at the level of the HSC compartment resulting in impaired MK maturation which can be further enhanced by the actions of a number of pro-inflammatory cytokines.

YKL-40 Promotes the Expression of Inflammatory Factors in Type Ⅱ Alveolar Epithelial Cell Model of A549 Cell Line

YKL-40, also known as chitinase-3-like-1 (CHI3L1), is a human cartilage glycoprotein-39, with its N-terminus consisting of tyrosine (Y), lysine (K), and leucine (L), hence the name YKL-40. In this study, we explored whether YKL-40 could promote the expression of inflammatory factors in type Ⅱ alveolar epithelial cells. A549 cells were cultured in vitro with interleukin (IL)-1β (20 ng/mL), IL-6 (20 ng/mL), tumor necrosis factor-alpha (TNF-α) (20 ng/mL), and interferon-gamma (IFN-γ) (20 ng/mL). The expression of YKL-40 transcription was determined by RT-qPCR. A549 cells were cultured with IL-1β at 5, 10, and 20 ng/mL and the expression of YKL-40 protein was determined by Western blot. A549 cells were cultured with recombinant YKL-40 protein at 0, 100, 500, and 1 000 ng/mL and the expression levels of IL-6 and IL-8 were measured by RT-qPCR. Three pairs of small interfering RNAs targeting YKL-40 (si- YKL-40-1/2/3) and the negative control (NC) were designed and used to transfect A549 cells, respectively, and the expression of YKL-40 was determined by RT-qPCR and Western blot. si- YKL-40-3 was screened out for subsequent experiments. In A549 cells, si- YKL-40-3 and si-NC were transfected and, then, IL-1β (20 ng/mL) was added in for culturing. The expression of YKL-40, IL-6, and IL-8 was determined by RT-qPCR and the expression of multiple factors in the supernatant was measured with the QAH-INF-1 kit. RT-qPCR results showed that IL-1β could up-regulate YKL-40 protein transcription level compared with that of the control group and the difference was statistically significant ( P<0.01), but IL-6, TNF-α, and IFN-γ could not up-regulate YKL-40 protein transcription level. Western blot results showed that IL-1β (20 ng/mL) could significantly promote the expression of YKL-40 and, compared with that of the control group, the differences showed by groups treated with different concentrations of IL-1β were all statistical significant ( P<0.01). After adding human recombinant YKL-40 protein to A549 cells, the results showed that the expression of inflammatory factors IL-6 and IL-8 was significantly increased and the difference was statistically significant compared with that of the control group ( P<0.05). After the expression of YKL-40 was decreased by si- YKL-40-3 transfection, the expression of IL-6 ( P<0.05), IL-8 ( P<0.05), and other inflammatory factors was inhibited compared with that of the control group. YKL-40 can promote the expression and secretion of IL-6, IL-8, and other acute inflammatory factors in A549 cell line, a type Ⅱ alveolar epithelial cell model, thus aggravating the inflammatory response. Targeted inhibition of YKL-40 expression may effectively inhibit inflammatory response.

Vascular Immune Evasion of Mesenchymal Glioblastoma Is Mediated by Interaction and Regulation of VE-Cadherin on PD-L1.

The mesenchymal subtype of glioblastoma (mGBM), which is characterized by rigorous vasculature, resists anti-tumor immune therapy. Here, we investigated the mechanistic link between tumor vascularization and the evasion of immune surveillance. Clinical datasets with GBM transcripts showed that the expression of the mesenchymal markers YKL-40 (CHI3L1) and Vimentin is correlated with elevated expression of PD-L1 and poor disease survival. Interestingly, the expression of PD-L1 was predominantly found in vascular endothelial cells. Orthotopic transplantation of glioma cells GL261 over-expressing YKL-40 in mice showed increased angiogenesis and decreased CD8+ T cell infiltration, resulting in a reduction in mouse survival. The exposure of recombinant YKL-40 protein induced PD-L1 and VE-cadherin (VE-cad) expression in endothelial cells and drove VE-cad-mediated nuclear translocation of β-catenin/LEF, where LEF upregulated PD-L1 expression. YKL-40 stimulated the dissociation of VE-cad from PD-L1, rendering PD-L1 available to interact with PD-1 from CD8+-positive TALL-104 lymphocytes and inhibit TALL-104 cytotoxicity. YKL-40 promoted TALL-104 cell migration and adhesion to endothelial cells via CCR5-dependent chemotaxis but blocked its anti-vascular immunity. Knockdown of VE-cad or the PD-L1 gene ablated the effects of YKL-40 and reinvigorated TALL-104 cell immunity against vessels. In summary, our study demonstrates a novel vascular immune escape mechanism by which mGBM promotes tumor vascularization and malignant transformation.

Assessment of Serum Chitinase-3-Like Protein 1 (YKL-40) in Lichen Planus

Abstract Introduction Lichen planus (LP) is a papulosquamous inflammatory disease of unknown etiology. Chitinase-3-like protein 1 (YKL-40) is proinflammatory multifunctional protein with significant role in immunity, inflammation and regulation of proliferation, differentiation and apoptosis of cell. Aim of the Study To investigate whether YKL-40 protein has any role in the pathogenesis of LP and to estimate its level in different LP patients with different degrees of severity in an attempt to reach a novel role of it in the pathogenesis of this disease in an attempt for better understanding and treatment of LP. Patients and Methods 38 patients with LP and 32 controls were included. Full history recording and physical examination were performed. Assessment of LP severity was done by LPAASI score and VAS score. Measurement of YKL-40 was done using ELISA. Results Assessment of serum YKL-40 revealed higher serum YKL-40 level in LP cases compared to controls with excellent discriminative power and sensitivity and specificity of 100%. A significant positive correlation was demonstrated between the YKL-40 level and LPAASI and pruritis scores. Conclusion Serum YKL-40 revealed significant high levels in LP patients compared to control subjects.

Associations of CSF PDGFRβ With Aging, Blood-Brain Barrier Damage, Neuroinflammation, and Alzheimer Disease Pathologic Changes.

Injured pericytes in the neurovascular unit release platelet-derived growth factor β (PDGFRβ) into the CSF. However, it is not clear how pericyte injury contributes to Alzheimer disease (AD)-related changes and blood-brain barrier (BBB) damage. We aimed to test whether CSF PDGFRβ was associated with different AD-associated and age-associated pathologic changes leading to dementia. PDGFRβ was measured in the CSF of 771 participants with cognitively unimpaired (CU, n = 408), mild cognitive impairment (MCI, n = 175), and dementia (n = 188) from the Swedish BioFINDER-2 cohort. We then checked association with β-amyloid (Aβ)-PET and tau-PET standardized uptake value ratio, APOE ε4 genotype and MRI measurements of cortical thickness, white matter lesions (WMLs), and cerebral blood flow. We also analyzed the role of CSF PDGFRβ in the relationship between aging, BBB dysfunction (measured by CSF/plasma albumin ratio, QAlb), and neuroinflammation (i.e., CSF levels of YKL-40 and glial fibrillary acidic protein [GFAP], preferentially expressed in reactive astrocytes). The cohort had a mean age of 67 years (CU = 62.8, MCI = 69.9, dementia = 70.4), and 50.1% were male (CU = 46.6%, MCI = 53.7%, dementia = 54.3%). Higher CSF PDGFRβ concentrations were related to higher age (b = 19.1, β = 0.5, 95% CI 16-22.2, p < 0.001), increased CSF neuroinflammatory markers of glial activation YKL-40 (b = 3.4, β = 0.5, 95% CI 2.8-3.9, p < 0.001), GFAP (b = 27.4, β = 0.4, 95% CI 20.9-33.9, p < 0.001), and worse BBB integrity measured by QAlb (b = 37.4, β = 0.2, 95% CI 24.9-49.9, p < 0.001). Age was also associated with worse BBB integrity, and this was partly mediated by PDGFRβ and neuroinflammatory markers (16%-33% of total effect). However, PDGFRβ showed no associations with APOE ε4 genotype, PET imaging of Aβ and tau pathology, or MRI measures of brain atrophy and WMLs (p > 0.05). In summary, pericyte damage, reflected by CSF PDGFRβ, may be involved in age-related BBB disruption together with neuroinflammation, but is not related to Alzheimer-related pathologic changes.

YKL-40 promotes proliferation and invasion of HTR-8/SVneo cells by activating akt/MMP9 signalling in placenta accreta spectrum disorders

YKL-40 is a secreted glycoprotein that can promote invasion, angiogenesis and inhibit apoptosis, and was highly expressed in a variety of tumours. In this paper, we investigated the impacts of YKL-40 on proliferation and invasion in HTR-8/SVneo cells during placenta accreta spectrum disorders (PAS) development. The levels of YKL-40 protein in late-pregnant placental tissue were detected using immunohistochemistry and Western blotting, and gene expression using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The proliferation, migration, invasion and apoptosis abilities of HTR-8/SVneo cells were detected by cell counting kit-8 (CCK-8), Transwell, scratch assay, and flow cytometry, respectively. Our current results showed that YKL-40 was significantly increased in the PAS group compared to the normal control group (P < 0.01). Biological function experiments showed that YKL-40 significantly promoted the proliferation, migration and invasion of HTR-8/SVneo cells, and inhibited cell apoptosis. Knockdown of YKL-40 inhibited the activation of Akt/MMP9 signalling in trophoblast cells. These data suggested that YKL-40 might be involved in the progression of PAS, which may be attributed to the regulation of Akt/MMP9 signalling pathway. IMPACT STATEMENT What is already known on this subject? YKL-40 is a secretory glycoprotein that can promote invasion, angiogenesis, and inhibit apoptosis and was highly expressed in a variety of tumours. Trophoblast cells resemble tumour cells in their migration and invasion. What the results of this study add? YKL-40 expression was significantly up-regulated in PAS. CCK-8 assays showed that YKL-40 remarkably enhanced the viability of HTR-8/SVneo cells. Scratch and Transwell assays demonstrated that YKL-40 significantly promoted the migration and invasion of HTR-8/SVneo cells. Additionally, YKL-40 attenuated apoptosis in HTR-8/SVneo cells. What the implications are of these findings for clinical practice and/or further research? Akt/MMP9 was involved in the regulation of YKL-40 on trophoblast invasion, which may provide theoretical basis and new ideas for the drug blocking intervention of placenta accreta.

A meta-analysis of the diagnostic utility of biomarkers in cerebrospinal fluid in Parkinson’s disease

Biomarkers play important roles in the diagnosis and differential diagnosis of Parkinson’s disease (PD). Thus, we carried out a systematic review and meta-analysis evaluating the diagnostic utility of cerebrospinal fluid (CSF) biomarkers to distinguish PD from atypical parkinsonian syndromes (APSs) and controls. Data for PD and APS and controls were extracted from 123 studies that reported the concentration of CSF biomarkers. Comparisons were presented using pooled Hedges’ g. Sources of heterogeneity were evaluated using meta-regression, and subgroup and sensitivity analyses. We found that compared with controls, PD patients had lower levels of amyloid beta 1-42, phosphorylated tau, total tau, total α-synuclein, Zn, DJ-1, and YKL-40, and higher levels of oligomeric and phosphorylated α-synuclein. Moreover, lower CSF levels of neurofilament light chain, t-tau, YKL-40, and C-reactive protein were found in PD patients compared to those with multiple system atrophy. PD patients also had lower levels of NFL and higher levels of Aβ42 compared with patients with progressive supranuclear palsy. Reduced levels of p-tau and t-tau and higher Aβ42 levels were found in PD patients compared with patients with dementia with Lewy bodies. Finally, reduced NFL levels were found in patients with PD compared with patients with cortical basal degeneration. Therefore, we believe that the combinations of t-α-syn, Aβ42, and NFL could be promising biomarkers for the differential diagnosis of PD and APSs.

A novel biomarker in acute cholecystitis: YKL-40

BackgroundThe 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). MethodsThis 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. ResultsThe 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). ConclusionWhen 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.

Diagnostic validity of serum YKL-40 as a non-invasive diagnostic marker of oesophageal varices in cirrhotic hepatitis C virus patients

BackgroundLiver cirrhosis is the last phase of chronic hepatitis C virus infection. During the compensated phase, portal pressure is still below the point where varices start to form. On the contrary, decompensated individuals have clinically significant portal hypertension. YKL-40 protein is categorized as an inflammatory protein and is related to various different variables in expressing the severity of hepatic fibrosis, including hepatic venous pressure gradient. The objective of this research was to evaluate the diagnostic validity of serum YKL-40 in cirrhotic hepatitis C virus patients as a predictive non-invasive marker for the diagnosis of oesophageal varices and to compare it to other non-invasive clinical, laboratory, and ultrasonographic parameters, as well as endoscopy with and without treatment modalities.ResultsThe present research was done on 80 participants visiting the Tropical Medicine Department at the Main University Hospital in Alexandria; they were divided into four groups, group I (n = 20) cirrhotic patients with no oesophageal varices, group II (n = 20) with small varices, group IIIa (n = 20) with large varices, and group IIIb same patients of group IIIa but after disappearance of varices by band ligation and medical treatment with carvedilol and group IV as apparently healthy control. YKL-40 in serum was evaluated using ELISA. Serum YKL-40 was statistically significantly higher in all cirrhotic patients than healthy controls (p = <0.001). Furthermore, it was statistically significantly greater in patients with small varices compared to those without varices (p = <0.001) and in large varices rather than no varices or small varices (p < 0.001) and (p < 0.001) respectively. However, there was no statistically significant difference between IIIa and IIIb (p = 0.881). In all tested groups, there was no correlation between serum YKL-40 and FIB-4 or APRI. However, only participants in group I exhibited a significant negative correlation between serum YKL-40 and AST/ALT ratio, whereas subjects in groups II and IIIa exhibited no significant correlation.ConclusionSerum YKL-40 could be used as a sensitive non-invasive predictor for diagnosis and grading of oesophageal varices but not for follow up after treatment.

YKL-40 and KL-6 Levels in Serum and Sputum of Patients Diagnosed With Hypersensitivity Pneumonitis

YKL-40 (chitinase 3-like-1) and Krebs von den Lungen-6 (KL-6) are 2 promising biomarkers that may have an important role in the management of interstitial lung diseases (ILD). The aim of this study was to investigate the values of KL-6 and YKL-40 as biomarkers in the diagnosis and prognosis of patients with hypersensitivity pneumonitis (HP). A cross-sectional study conducted in 49 patients diagnosed with HP due to exposure to birds (n= 32) or fungi (n= 17), 48 patients with other ILD, and 67 healthy volunteers. Patients with HP were divided into fibrotic and nonfibrotic. Serum and sputum YKL-40 and KL-6 levels were determined using commercial enzyme-linked immunosorbent assay kits. Receiver operating characteristic (ROC) curves were used to determine the sensitivity and specificity of both biomarkers for the diagnosis of HP. Pulmonary function tests were performed in patients during follow-up. KL-6 and YKL-40 levels were significantly higher in serum of patients with HP exposed to birds with a fibrotic pattern than in controls (P < .0001 and .0055, respectively). Serum KL-6 levels were also significantly higher in patients with fibrotic HP exposed to fungi compared with the control group (P= .0001). In patients with HP exposed to fungi, sputum KL-6 and YKL-40 levels were higher in those with a fibrotic pattern (P= .0289 and .016, respectively). ROC analysis showed that the range between 55-121 ng/mL for serum YKL-40 levels and 346-1441 U/mL for serum KL-6 levels had the best sensitivity and specificity for discriminating between patients with HP, healthy controls, and patients with idiopathic pulmonary fibrosis (IPF). In patients with HP, serum KL-6 levels correlated negatively with total lung capacity (r=-0.485; P= .0103) and diffusing capacity of the lungs for carbon monoxide (r=-0.534; P= .0002) at 12 months. Both KL-6 and YKL-40 proteins seem to be capable of distinguishing patients with HP from healthy individuals and from patients with IPF. Their sensitivity and specificity confirm their potential role as biomarkers. KL-6 may also be a predictor of disease progression.

Serum chitotriosidase and YKL-40 in acute pancreatitis: Reliability as prognostic marker for disease severity and correlation with inflammatory markers

Chitotriosidase and YKL-40, also called chitinase 3-like protein 1, are homologs of family 18 glycosyl hydrolases, secreted by human macrophages and granulocytes under inflammatory conditions. Although increased levels of chitotriosidase and YKL-40 are linked with several inflammatory diseases, the physiological utility of these two enzymes is still not fully characterized. This study aims to analyse the serum YKL-40 and chitotriosidase levels of acute pancreatitis patients to assess whether their activity correlates with acute pancreatitis and its severity. Chitotriosidase and YKL-40 levels, along with routine laboratory parameters, were determined from the serum samples of 41 acute pancreatitis patients, at both onset and remission (male/female: 22/19), and 39 healthy subjects (male/female: 19/20). The Modified Glasgow Prognostic Score was used to predict the severity of the disease, and a correlation analysis was performed between study variables. A statistically significant increase in both chitotriosidase and YKL-40 levels was observed in acute pancreatitis patients compared to healthy controls (P < 0.001). Higher levels of YKL-40, chitotriosidase and C-reactive protein were found in patients with acute pancreatitis at onset than in remission. The correlation analysis showed a statistically significant association between YKL-40 and chitotriosidase (p = 0.039, r = 0.323). The cut-off point for YKL-40, for detecting acute pancreatitis, was 60.3 with a sensitivity and specificity of 84.9% and 84.6% (AUC: 0.890). The optimum cut-off points for chitotriosidase, for detecting acute pancreatitis, was 33.5 with a sensitivity and specificity of 79.5% and 78.4% (AUC: 0.899). Elevated YKL-40 and chitotriosidase levels in acute pancreatitis patients demonstrate the importance of possible macrophage involvement in the pancreatic microenvironment during acute pancreatitis progression.

Serum chitotriosidase and YKL-40 in acute pancreatitis: Reliability as prognostic marker for disease severity and correlation with inflammatory markers.

Chitotriosidase and YKL-40, also called chitinase 3-like protein 1, are homologs of family 18 glycosyl hydrolases, secreted by human macrophages and granulocytes under inflammatory conditions. Although increased levels of chitotriosidase and YKL-40 are linked with several inflammatory diseases, the physiological utility of these two enzymes is still not fully characterized. This study aims to analyse the serum YKL-40 and chitotriosidase levels of acute pancreatitis patients to assess whether their activity correlates with acute pancreatitis and its severity. Chitotriosidase and YKL-40 levels, along with routine laboratory parameters, were determined from the serum samples of 41 acute pancreatitis patients, at both onset and remission (male/female: 22/19), and 39 healthy subjects (male/female: 19/20). The Modified Glasgow Prognostic Score was used to predict the severity of the disease, and a correlation analysis was performed between study variables. A statistically significant increase in both chitotriosidase and YKL-40 levels was observed in acute pancreatitis patients compared to healthy controls (P < 0.001). Higher levels of YKL-40, chitotriosidase and C-reactive protein were found in patients with acute pancreatitis at onset than in remission. The correlation analysis showed a statistically significant association between YKL-40 and chitotriosidase (p = 0.039, r = 0.323). The cut-off point for YKL-40, for detecting acute pancreatitis, was 60.3 with a sensitivity and specificity of 84.9% and 84.6% (AUC: 0.890). The optimum cut-off points for chitotriosidase, for detecting acute pancreatitis, was 33.5 with a sensitivity and specificity of 79.5% and 78.4% (AUC: 0.899). Elevated YKL-40 and chitotriosidase levels in acute pancreatitis patients demonstrate the importance of possible macrophage involvement in the pancreatic microenvironment during acute pancreatitis progression.

Reciprocal induction of hepatitis C virus replication and stimulation of hepatic profibrogenic cytokine release and cellular viability by YKL-40.

BackgroundPrevious studies have suggested the YKL-40/chitinase 3-like protein 1 protein is upregulated in chronic hepatitis C virus (HCV) infection with fibrosis. We sought to determine whether HCV regulates YKL-40 expression and to elucidate the mechanisms by which YKL-40 mediates the liver fibrosis caused by HCV infection.MethodsWe used purified protein, small molecule inhibitors and short-interfering RNAs to over-express or knock down certain kinases to explore the mechanisms underlying the regulation by HCV of YKL-40 expression in the Japanese fulminant hepatitis 1 (JFH1) model.ResultsHCV induced YKL-40 production in hepatic parenchymal cells. Further, HCV-mediated upregulation of YKL-40 through cooperative induction of tumor necrosis factor-α (TNF-α) and reactive oxygen species (ROS)-mitogen-activated protein kinase MAPKs, which are nuclear factor-κB (NF-κB)-dependent pathways. YKL-40 protein also mildly increased HCV replication, triggering hepatic profibrogenic cytokine release and cellular viability as feedback. Additionally, hepatic parenchymal cells were the sole source of YKL-40 production in the infectious JFH1 model, whereas YKL-40 was under-detected in hepatic stellate cells (HSCs) in the presence or absence of the JFH1 supernatant, which was not investigated so far.ConclusionsHCV induced and maintained secretion of YKL-40 through sustained activation of NF-κB via cooperative induction of the TNF-α and ROS-MAPKs pathways. HCV interacted with YKL-40 to enhance the progression of hepatic fibrosis. These findings support a potential role for blockade of YKL-40 as an antifibrotic strategy.