Signal transducer and activator of transcription 3 (STAT3) and Chemokine CX3C ligand 1 (Fractalkine/CX3CL1) play important roles in vascular inflammation and injury. To study if STAT3 promotes vascular endothelial cell proliferation and migration through fractalkine, we overexpressed or knocked down STAT3 in vascular endothelial cells, and used quantitative real-time PCR and Western blotting to determine the effect of STAT3 on fractalkine expression. The wild type and STAT3 binding site mutant fractalkine promoter luciferase reporter plasmids were constructed, and luciferase activity assays were used to explore the effect of STAT3 on the transcriptional activity of the fractalkine promoter. MTT assays were used to detect the effect of overexpression or knockdown of STAT3 or fractalkine on the proliferation rate of vascular endothelial cells. Scratch assays were used to detect the effect of overexpression or knockdown of STAT3 or fractalkine on vascular endothelial cell migration. There results showed that overexpression of STAT3 could promote fractalkine expression, and knockdown of STAT3 could down-regulate fractalkine expression. STAT3 could directly bind to the promoter of fractalkine to promote its transcriptional activity via binding the GAS site of the fractalkine promoter. Knockdown of STAT3 could inhibit the migration of vascular endothelial cell, and overexpression of fractalkine antagonized this inhibition. Our data concluded that STAT3 promotes the proliferation and migration of vascular endothelial cell by binding the GAS site of the fractalkine promoter to promote fractalkine transcriptional activity and expression.
Cell Proliferation ; Chemokine CX3CL1 ; Endothelial Cells ; Promoter Regions, Genetic ; STAT3 Transcription Factor

OBJECTIVETo investigate the expression of fractalkine (FKN) in the blood and renal tissues of patients with lupus nephritis and explore its significance.

METHODSAccording to the pathological classification, 48 patients with lupus nephritis were divided into mild group (22 cases) and severe group (26 cases), with 26 healthy subjects as the control group. RT-PCR and enzyme-linked immunosorbent assay were employed to detect the expression of FKN mRNA and protein in the blood of the subjects, and FKN expression and localization in the renal tissue of the patients with lupus nephritis were detected using immunohistochemical staining.

RESULTSThe patients in both the mild and severe groups showed significantly increased expression of blood FKN mRNA and protein compared with the normal controls, and the increase was more obvious in severe cases (P<0.01). In the renal tissues of the patients, FKN was located mainly in the cytoplasm of the glomerular podocytes and renal tubular epithelial, and the number of positive glomerular cells number was significantly greater in severe cases than in the mild cases (P<0.01); FKN expression in the cortical interstitium did not show a significant difference between the 3 groups.

CONCLUSIONFKN expression in the blood and glomeruli of patients with lupus nephritis is related to the severity of renal pathologies.

Adult ; Case-Control Studies ; Chemokine CX3CL1 ; blood ; metabolism ; Female ; Humans ; Kidney ; metabolism ; Lupus Nephritis ; blood ; metabolism ; Middle Aged

BACKGROUND/AIMS: Abnormal immune regulation and increased intestinal permeability augmenting the passage of bacterial molecules that can activate immune cells, such as monocytes/macrophages, have been reported in irritable bowel syndrome (IBS). The aim was to compare the maturation phenotype of monocytes/macrophages (CD14+) from IBS patients and controls in the presence or absence of Escherichia coli lipopolysaccharides (LPS), in vitro. METHODS: Mononuclear cells were isolated from peripheral blood of 20 Rome II-IBS patients and 19 controls and cultured with or without LPS for 72 hours. The maturation phenotype was examined by flow cytometry as follows: M1-Early (CD11c⁺CD206⁻), M2-Advanced (CD11⁻CD206⁺CX3CR1⁺); expression of membrane markers was reported as mean fluorescence intensity (MFI). The Mann-Whitney test was used and significance was set at P < 0.05. RESULTS: In CD14+ cells, CD11c expression decreased with vs without LPS both in IBS (MFI: 8766.0 ± 730.2 vs 12 920.0 ± 949.2, P < 0.001) and controls (8233.0 ± 613.9 vs 13 750.0 ± 743.3, P < 0.001). M1-Early cells without LPS, showed lower CD11c expression in IBS than controls (MFI: 11 540.0 ± 537.5 vs 13 860.0 ± 893.7, P = 0.040), while both groups showed less CD11c in response to LPS (P < 0.01). Furthermore, the percentage of “Intermediate” (CD11c⁺CD206⁺CX3CR1⁺) cells without LPS, was higher in IBS than controls (IBS = 9.5 ± 1.5% vs C = 4.9 ± 1.4%, P < 0.001). Finally, fractalkine receptor (CX3CR1) expression on M2-Advanced cells was increased when treated with LPS in controls but not in IBS (P < 0.001). CONCLUSIONS: The initial phase of monocyte/macrophage maturation appears to be more advanced in IBS compared to controls. However, the decreased CX3CR1 in patients with IBS, compared to controls, when stimulated with LPS suggests a state of immune activation in IBS.
Chemokine CX3CL1 ; Escherichia coli ; Flow Cytometry ; Fluorescence ; Humans ; In Vitro Techniques ; Irritable Bowel Syndrome* ; Lipopolysaccharides* ; Membranes ; Monocytes ; Permeability ; Phenotype*

Chemokine (C-X3-C motif) ligand 1 (CX₃CL1, also known as fractalkine) and its receptor chemokine (C-X3-C motif) receptor 1 (CX₃CR1) are widely expressed in immune cells and non-immune cells throughout organisms. However, their expression is mostly cell type-specific in each tissue. CX₃CR1 expression can be found in monocytes, macrophages, dendritic cells, T cells, and natural killer (NK) cells. Interaction between CX3CL1 and CX₃CL1 can mediate chemotaxis of immune cells according to concentration gradient of ligands. CX₃CL1 expressing immune cells have a main role in either pro-inflammatory or anti-inflammatory response depending on environmental condition. In a given tissue such as bone marrow, brain, lung, liver, gut, and cancer, CX₃CL1 expressing cells can maintain tissue homeostasis. Under pathologic conditions, however, CX₃CL1 expressing cells can play a critical role in disease pathogenesis. Here, we discuss recent progresses of CX3CL1/CX₃CL1 in major tissues and their relationships with human diseases.
Bone Marrow ; Brain ; Chemokine CX3CL1 ; Chemotaxis ; Dendritic Cells ; Homeostasis ; Humans ; Ligands ; Liver ; Lung ; Macrophages ; Monocytes ; Organ Specificity ; T-Lymphocytes

OBJECTIVE: To explore the mechanism by which fractalkine (CX3CL1; FKN) inhibits lipopolysaccharide (LPS)-induced immunological response in RAW264.7 cells. METHODS: A RAW264.7 cell model overexpressing FKN was established by transfection with the lentiviral vector CX3CL1. The effects of LPS, ICG-001 (a Wnt/β-catenin signaling pathway inhibitor), either alone or in combination, on M1 polarization of na?ve and FKN-overexpressing RAW264.7 cells were evaluated by detecting of intereukin-6 (IL-6) and tumor necrosis factor-α (TNF- RESULTS: The RAW264.7 cell model of FKN overexpression was successfully established. In na?ve RAW264.7 cells, treatment with both ICG-001 and LPS, as compared with LPS alone, significant promoted TNF- CONCLUSIONS FKN overexpression suppresses LPS-induced M1 type polarization of RAW264.7 cells by activating Wnt/β-catenin signaling pathway.
Animals ; Chemokine CX3CL1 ; Lipopolysaccharides/pharmacology* ; Macrophages ; Mice ; RAW 264.7 Cells ; Tumor Necrosis Factor-alpha ; Wnt Signaling Pathway

A transient ischemic attack (TIA) can cause reversible and delayed impairment of cognition, but the specific mechanisms are still unclear. Annexin a1 (ANXA1) is a phospholipid-binding protein. Here, we confirmed that cognition and hippocampal synapses were impaired in TIA-treated mice, and this could be rescued by multiple mild stimulations (MMS). TIA promoted the interaction of ANXA1 and CX3CR1, increased the membrane distribution of CX3CR1 in microglia, and thus enhanced the CX3CR1 and CX3CL1 interaction. These phenomena induced by TIA could be reversed by MMS. Meanwhile, the CX3CR1 membrane distribution and CX3CR1-CX3CL1 interaction were upregulated in primary cultured microglia overexpressing ANXA1, and the spine density was significantly reduced in co-cultured microglia overexpressing ANXA1 and neurons. Moreover, ANXA1 overexpression in microglia abolished the protection of MMS after TIA. Collectively, our study provides a potential strategy for treating the delayed synaptic injury caused by TIA.
Animals ; Annexin A1/metabolism* ; CX3C Chemokine Receptor 1/metabolism* ; Chemokine CX3CL1 ; Cognition ; Dendritic Spines/metabolism* ; Ischemic Attack, Transient ; Mice ; Microglia/metabolism*

OBJECTIVE: To investigate the distribution of mast cells in nasal polyps. METHOD: Biopsy specimens from patients with nasal polyps (n = 20) and control patients (n = 8) were obtained and included in this study. The distribution of mast cells in nasal polyps and the expression of chemokines (CCL5, CCL11, CX3CL1, IL-8, IL-6) in the epithelial cells of normal nasal mucosa and nasal polyps was determined by immunohistochemistry. RESULT: Mast cells migrate to intraepithelial in nasal polyps and the expression of chemokines (CCL5, CCL11, CX3CL1, IL-8) was up regulated in the epithelial cells of nasal polyps compare to normal nasal mucosa. CONCLUSION Our findings showed that mast cells migrate to intraepithelial in nasal polyps and the over expression of chemotaxins (CCL5, CCL11, CX3CL1, IL-8) may be response for mast cells' migration in nasal polyps. Mast cells might be associated with the development of nasal polyps.
Chemokine CCL11 ; metabolism ; Chemokine CCL5 ; metabolism ; Chemokine CX3CL1 ; metabolism ; Epithelial Cells ; metabolism ; Humans ; Immunohistochemistry ; Interleukin-6 ; metabolism ; Interleukin-8 ; metabolism ; Mast Cells ; metabolism ; pathology ; Nasal Mucosa ; cytology ; metabolism ; Nasal Polyps ; metabolism ; pathology ; Up-Regulation

OBJECTIVETo explore the association of fractalkine (FKN) and CD11c expressions oncommon carotid artery atherosclerotic plaques from apoE(-/-) mice with the severity of atherosclerotic lesions.

METHODSTotally 24 apoE(-/-) mice were divided into two groups and fed on a high-fat diet or a normal diet for 12 weeks. Then the blood lipids as well as the plaque area and vascular stenosis rate of the common carotid artery were measured to evaluate the severity of atherosclerotic lesions of the animals. Moreover, immunohistochemical staining was performed to examine the levels of FKN and CD11c expression.

RESULTSThe plaque areas and vascular stenosis rates of the common carotid artery in the experimental group were remarkably larger than those in control group (about 4-fold and 2-fold, respectively). The level of FKN expression in the experimental group was 2 times of that in the control group (P<0.05), and the number of CD11c (+) cells in the plaques in the experimental group was about 4 times of than in the control group (P<0.05).

CONCLUSIONThe expressions of chemokine and FKN remarkably increase in apoE (-/-) atherosclerotic plaques, suggesting that chemokine and FKN may paly important roles in the development of atherosclerosis.

Animals ; Atherosclerosis ; metabolism ; pathology ; CD11 Antigens ; metabolism ; Chemokine CX3CL1 ; metabolism ; Diet, High-Fat ; Disease Models, Animal ; Mice ; Mice, Knockout ; Plaque, Atherosclerotic ; pathology

OBJECTIVETo study the expression of Fractalkine (FKN) in the kidney tissue of rats with renal fibrosis and the effect of IL-18BP on FKN.

METHODSMale Wister rats were randomly assigned to sham-operation (n=24), unilatral ureteral obstruction (UUO, n=22), and IL-18 binding protein (IL-18BP) treatment groups (n=23). The UUO model was prepared by unilateral ureteral ligation in the later two groups. The IL-18BP treatment group received an intraperitoneal injection of IL-18BP (0.1 mg/kg) every other day after UUO inducement, for 7 times, while normal saline was administered in the other two groups. Seven or eight rats of every group were sacrificed at 3, 7 or 14 days after IL-18BP or normal saline injections. FKN levels at various times were detected by immunohistochemistry and Western blot.

RESULTSCompared with the sham-operation group, FKN levels in the kidney tissue of the untreated UUO group increased significantly at all time points (P<0.01). IL-18BP treatment decreased significantly FKN levels in the kidney tissue at all time points compared with the untreated UUO group (P<0.01).

CONCLUSIONSIL-18BP treatment may down-regulate the increased FKN levels of the rat kidney tissue caused by UUO, possibly thus delays the occurrence and development of renal fibrosis.

Animals ; Blotting, Western ; Chemokine CX3CL1 ; genetics ; Fibrosis ; Intercellular Signaling Peptides and Proteins ; pharmacology ; Kidney ; immunology ; pathology ; Male ; Rats ; Rats, Wistar ; Ureteral Obstruction ; immunology

AIMTo investigate the effect of fractalkine on cell proliferation of cultured rat pulmonary artery smooth muscle cells (PASMCs) in vitro.

METHODSRat PASMCs were cultured in vitro, and treated with different concentrations (10(-10), 10(-9), 10(-8) mol/L) of fractalkine for 12 h, 24 h and 48 h. The cell proliferation was quantified by MTT assay. The cell cycle of PASMCs was measured by flow cytometric(FCM) analysis.

RESULTSMTT assay showed that fractalkine promoted significantly the proliferation of PASMCs, and the effect was concentration-dependent. FCM analysis indicated that fractalkine increased the percentage of S phase and proliferative index (PI). The percentage of S phase and PI of PASMCs were increased after treated with fractalkine for 12 hours, which reached a maximal level at 24 hours.

CONCLUSIONFractalkine promotes rat PASMCs proliferation in a concentration-dependent manner.

Animals ; Cell Proliferation ; drug effects ; Cells, Cultured ; Chemokine CX3CL1 ; pharmacology ; Male ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; cytology ; drug effects ; Pulmonary Artery ; cytology ; Rats ; Rats, Sprague-Dawley