Expression Of CXC Chemokine Ligand Research Articles

Lipopolysaccharide and lipoteichoic acid regulate the PI3K/AKT pathway through osteopontin/integrin β3 to promote malignant progression of non-small cell lung cancer.

Lung cancer (LC) is a malignancy with one of the highest mortality rates. Respiratory microbiota is considered to play a key role in the development of LC, but the molecular mechanisms are rarely studied. We used lipopolysaccharide (LPS) and lipoteichoic acid (LTA) to study human lung cancer cell lines PC9 and H1299. The gene expression of CXC chemokine ligand (CXCL)1/6, interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). The Cell-Counting Kit 8 (CCK-8) was used to analyze cell proliferation. Transwell assays were performed to analyze cell migration ability. Flow cytometry was used to observe cell apoptosis. Western blot and qRT-PCR were used to analyze the expression of secreted phosphoprotein 1 (SPP1), toll-like receptor (TLR)-2/4, and NLR family pyrin domain containing 3 (NLRP3) to determine the mechanism of LPS + LTA. We evaluated the effect of LPS + LTA on cisplatin sensibility by analyzing cell proliferation, apoptosis, and caspase-3/9 expression levels. We observed the proliferation activity, apoptosis, and migration ability of cells in which SPP1 had been transfected small interfering (si) negative control (NC) and integrin β3 siRNA. Then the mRNA expression level and protein expression of PI3K, AKT, and ERK were analyzed. Finally, the nude mouse tumor transplantation model was conducted to verify. We studied that in two cell lines, the expression level of inflammatory factors in LPS+LTA group was significantly higher than that in single treatment group (P<0.001). We explored LPS + LTA combined treatment group significantly increased the expression of NLRP3 and genes and proteins. LPS + LTA + Cisplatin group could significantly reduce the inhibitory effect of LPS on cell proliferation (P<0.001), reduce the apoptosis rate (P<0.001) and significantly reduce the expression levels of caspase-3/9 (P<0.001) compared with Cisplatin group. Finally, we verified that LPS and LTA could increase osteopontin (OPN)/integrin β3 expression and activate the PI3K/AKT pathway to promote malignant progression of LC in vitro studies. This study provides a theoretical basis for further exploration of the influence of lung microbiota on NSCLC and the optimization of LC treatment in the future.

Soluble triggering receptor expressed on myeloid cells 2 (sTREM2) positively regulates lipopolysaccharide-induced expression of CXC chemokine ligand 10 and 11 in mouse macrophages

TREM2 (Triggering receptor expressed on myeloid cells 2) is the causative gene for Nasu-Hakola disease, which is characterized by multiple bone cysts and leukoencephalopathy. In addition, mutations in this gene have been found to be correlated with the onset of Alzheimer's disease. TREM2 is an immunoreceptor expressed on dendritic cells, microglia, osteoclasts, and macrophages. TREM2 on the cell membrane is shed by some proteases and released as soluble TREM2 (sTREM2). Meanwhile, several TREM2 ligands have been reported, and lipopolysaccharide (LPS) is one of the candidates. Using RNA interference to examine TREM2-mediated LPS response in macrophages, we identified five chemokines whose expression was induced via TREM2. Furthermore, we showed that LPS-induced expression of CXC-motif chemokine ligand (Cxcl10) and Cxcl11 among the five chemokines was mediated in part through sTREM2. These results suggest that sTREM2 has cytokine-like functions in macrophages.

Opposing Effects of Granulocyte Colony-Stimulating Factor on the Initiation and Progression of Breast Cancer Bone Metastases.

Granulocyte colony stimulating factor (G-CSF), an essential cytokine regulating granulopoiesis, is expressed in a substantial proportion of breast cancers, and it has been implicated in cancer progression. Here, we examined effects of G-CSF on the development of bone metastases of breast cancer using immunocompetent mouse models. The expression of CXC chemokine ligand 12 (CXCL12) in bone marrow stromal cells, which plays a critical role in the maintenance of hematopoietic stem cells and also in cancer cell homing to bone, was markedly decreased in mice treated with G-CSF. Flow cytometric analysis revealed that pretreatment of mice with G-CSF reduced the number of bone-homing cancer cells. G-CSF also increased the population of myeloid-derived suppressor cells (MDSCs) in bone marrow. Depletion of MDSCs using anti-Gr-1 antibody treatment significantly decreased the metastatic tumor burden in bone. The overall effects of G-CSF on bone metastases were finally examined using two different treatment protocols. When mice were treated with G-CSF prior to the tumor cell inoculation, G-CSF did not change bone metastatic-tumor burden. In contrast, when G-CSF treatment was started after the tumor cells had homed to bone, G-CSF significantly accelerated bone metastases formation. These results suggest that G-CSF suppressed cancer cell homing to bone by downregulating CXCL12 expression in bone marrow stromal cells, whereas G-CSF stimulated the progression of bone metastases at least in part by MDSC-mediated mechanisms. IMPLICATIONS: G-CSF had opposing effects on the initiation and progression of bone metastases of breast cancer and the balance may regulate the metastatic tumor burden.

Expression and clinical significance of CXC chemokine ligand 10 in glioma

Objective: To analyze the expression of CXC chemokine ligand 10 (CXCL10) in glioma and its clinical significance through bioinformatics. Methods: The expression level of CXCL10 in glioma, and its prognostic significance, gene ontology (GO) function annotation, Kyoto Encyclopedia of Genes and Genome (KEGG) pathway enrichment and the correlation of tumor cell purity were analyzed in TCGA, CGGA, MetaScape, TIMER databases. In addition, 34 clinical glioma tissues were collected for Western Blot and immunohistochemistry to further verify the correlation between CXCL10 and glioma. Results: CGGA and TCGA database analysis showed that with the increase of WHO grade, the expression of CXCL10 in gliomas increased (P<0.01). The overall survival rate of patients with high CXCL10 expression was significantly lower than that of patients with low expression (χ2 =148.1,P<0.05). Among patients with grade Ⅳ glioblastoma who received radiotherapy or chemotherapy, the patients with low CXCL10 expression were associated with good survival (χ2 =6.714,P<0.05;χ2 =5.618,P<0.05). Moreover, GO and KEGG analysis showed that genes co-expressed with CXCL10 were mainly enriched in the biological processes such as cytokine-mediated signaling pathways, regulating adaptive immune responses and inflammatory responses. Furthermore, TIMER database analysis showed that CXCL10 was negatively correlated with the purity of glioma cells (LGG: r=-0.129;GBM: r=-0.165;P<0.05). Similarly, clinical sample analysis also showed that the expression level of CXCL10 increased in glioma, and it increased with the grade of glioma (all P<0.05). Conclusion: The expression of CXCL10 is up-regulated in glioma as well as it increased with the malignant degree of glioma. At the same time, the high expression of CXCL10 in glioma is closely related to the poor prognosis of patients.

Endothelial cells are a source of Nestin expression in Pulmonary Arterial Hypertension.

Uncontrolled proliferation of endothelial cells is essential to the pathogenesis of pulmonary arterial hypertension (PAH). Both proliferation and cytoskeleton reorganization are associated with upregulation of the intermediate filament protein Nestin. Recently, accumulation of Nestin-expressing cells was found in pulmonary vascular lesions of PAH patients. The goal of this study is to determine if Nestin expression contributes to endothelial proliferation in pulmonary arterial hypertension, using both lung tissues and endothelial cells. Here we found that endothelial cells from complex and plexiform lesions of PAH patients expressed Nestin. These Nestin+ cells further stained positive for the angiogenic factors CXC chemokine ligand 12 and Wnt1. Likewise, in the chronic hypoxia/SU5416 animal model of pulmonary hypertension, Nestin+ endothelial cells were found in occlusive pulmonary vascular lesions. In vitro, both growing rat and human lung endothelial cells expressed Nestin protein. When Nestin was overexpressed in endothelial cells (both rat and human), Nestin overexpression promoted proliferation and expression of CXC chemokine ligand 12. Nestin overexpression further increased angiogenic tube formation in vitro. Conclusions: We found increased Nestin expression from endothelial cells of occlusive lung vascular lesions in severe pulmonary hypertension. Elevated Nestin expression likely contributes to unchecked pulmonary vascular proliferation and angiogenesis, possibly via induction of CXC chemokine ligand 12. Additional studies are required to determine whether targeting Nestin would be beneficial to treat PAH.

Regulatory effect of immunosuppressive agents in mice with renal ischemia reperfusion injury

This study was designed to investigate the regulatory effect of rapamycin in mice with renal ischemia-reperfusion injury. A total of 100 mice were randomly divided into normal control, sham operation, model and experimental groups with 25 rats in each group. Mice in the experimental group were subjected to rapamycin gavage. Mice in each group were sacrificed 24 h after operation. Then, blood, spleen and left kidney were collected. PAS staining was used for semi-quantitative analysis of renal pathological injury. Serum creatinine (SCr) and blood urea nitrogen (BUN) levels were measured. TUNEL method was used to detect cell apoptosis. Flow cytometry was used to detect the percentage of NKT cells. The expression of CXC chemokine ligand 10 (CXCL10), hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) mRNA were detected by RT-qPCR. Semi-quantitative scoring of renal pathological injury showed that pathological injury score of the experimental group was significantly lower than that of the model group (p<0.05). Serum levels of SCr and BUN in the experimental group was compared to those in the model group (p<0.05). The number of apoptotic cells in the experimental group was compared to that of the model group (p<0.05). The percentage of NKT cells in the experimental group was compared to that of the model group (p<0.05). The percentage of NKT cells was significantly higher in the kidney and peripheral blood of the experimental group than that in the model group (p<0.05). The expression levels of HIF-1α and VEGF mRNA in the model and experimental groups were significantly lower in the experimental group than those in the model group (p<0.05). The expression levels of CXCL10 mRNA in the model and experimental groups were significantly higher in the experimental group than those in the model group (p<0.05). The results indicated that rapamycin can significantly upregulate the expression level of CXCL9 and promote the accumulation of NKT cells in kidney from spleen through peripheral blood. Rapamycin can also inhibit the HIF-1α expression level and protect renal ischemia-reperfusion injury.

Nitrosporeusine analogue ameliorates Chandipura virus induced inflammatory response in CNS via NFκb inactivation in microglia.

Chandipura Virus (CHPV), a negative-stranded RNA virus belonging to the Rhabdoviridae family, has been previously reported to bring neuronal apoptosis by activating several factors leading to neurodegeneration. Following virus infection of the central nervous system, microglia, the ontogenetic and functional equivalents of macrophages in somatic tissues gets activated and starts secreting chemokines, thereby recruiting peripheral leukocytes into the brain parenchyma. In the present study, we have systemically examined the effect of CHPV on microglia and the activation of cellular signalling pathways leading to chemokine expression upon CHPV infection. Protein and mRNA expression profiles of chemokine genes revealed that CHPV infection strongly induces the expression of CXC chemokine ligand 10 (CXCL10) and CC chemokine ligand 5 (CCL5) in microglia. CHPV infection triggered the activation of signalling pathways mediated by mitogen-activated protein kinases, including p38, JNK 1 and 2, and nuclear factor κB (NF-kappaB). CHPV-induced expression of CXCL10 and CCL5 was achieved by the activation of p38 and NF-kappaB pathways. Considering the important role of inflammation in neurodegeneration, we have targeted NF-kappaB using a newly synthesised natural product nitrosporeusine analogue and showed incapability of microglial supernatant of inducing apoptosis in neurons after treatment.

Expression of CXC chemokine ligand 12 and CXC chemokine receptor 4 in non-small cell lung cancer tissues and clinical implication

Objective By detecting the expression of CXC chemokine ligand 12 (CXCL12) and CXC chemokine receptor 4 (CXCR4) in non-small cell lung cancer (NSCLC) tissues and adjacent normal lung tissues, we try to investigate the correlation between the expression of CXCL12/CXCR4 and clinical parameters. Methods Immunohistochemical staining method was used to detect the expression of CXCL12 and CXCR4 in cancer tissues and matched normal lung tissues adjacent to carcinoma of 62 cases of NSCLC. Under the microscope at high magnification, positive staining (+ ) was recorded when the number of positive cells accounted for more than or equal to 10%, and negative staining (-) was recorded when the number of positive cells accounted for less than 10%. The positive expression rate and the relationship between the various clinical parameters were analyzed. Results The positive expression rate of CXCL12 in NSCLC tissues and normal lung tissue adjacent to carcinoma was 73.8% and 15.0% respectively (P=0.040). The positive expression of CXCR4 was detected in 33 cases and 2 cases of NSCLC tissues and normal lung tissue adjacent to carcinoma respectively (P=0.030). The positive expression rate of CXCL12 in stage Ⅲa-Ⅲb was 90.9%, and 55.5% in stage Ⅱa-Ⅱb. The positive expression rate of CXCR4 in Ⅲa-Ⅲb was 90.9%, and 55.5% in stage Ⅱa-Ⅱb (P=0.030). The positive expression rate of CXCL12 in mediastinal lymph node with metastasis was 94.7%, and that in the mediastinal lymph node without metastasis was 56.5%. The expression of CXCL12 and CXCR4 in NSCLC tissues was consistent. Conclusion CXCL12 and CXCR4 expression in NSCLC tissues has the effect to promote cancer. The positive expression of CXCL12 and CXCR4 is associated with TNM staging and mediastinal lymph node metastasis. The specific binding of CXCL12 and CXCR4 may promote lymph node metastasis. Key words: CXC chemokine ligand 12; CXC chemokine receptor 4; Non-small-cell lung carcinoma; Immunohistochemisty

Expression of CXC chemokine ligand 16/CXC chemokine receptor 6 in colon cancer and its effect on proliferation, invasion and metastasis of colon cancer

Objective To investigate the expression of CXC chemokine ligand 16 (CXCL16)/CXC chemokine receptor 6 (CXCR6) in colon cancer and its effect on the proliferation, invasion and metastasis of colon cancer. Methods Immunohistochemistry was used to detect the expression of CXCL16/CXCR6 in colorectal cancer tissues and para carcinoma tissues, and colon cancer cell lines: SW480, LoVo, HCT116. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect the expression of CXCL16 mRNA and CXCR6 mRNA. The methyl thiazol tetrazolium (MTT) and Transwell were used to analyze the effects of CXCL16/CXCR6 on the proliferation, invasion and metastasis of colon cancer cells by CXCR16-RNA lentiviral vector transfected SW480 cells. Results In 56 cases of colon cancer, there were 48 cases positive for CXCL12 expression, and 47 positive for CXCR6 expression, with the positive expression rate being 85.7% and 83.9% respectively, significantly higher than in the adjacent normal tissues (26.7%, 33.3%), the difference was statistically significant (χ2=18.542, P=0.005; χ2=19.464, P=0.005). CXCL16 and CXCR6 in colon cancer cell lines SW480, LoVo, HCT116 were all positively expressed. The RT-PCR revealed that the expression of CXCL16 and CXCR6 mRNA in cancerous tissues was statistically significantly higher than in the normal tissues adjacent to carcinoma (t=2.592, P=0.008; t=2.364, P=0.003). CXCL16 and CXCR6 mRNA was highly expressed in the cancer cell linves (P=0.232). After transfection with lentivirus vector, MTT experiment showed that the proliferation of CXCL16-short hairpin RNA (shRNA) group was significantly lower than the control group (P=0.002). Transwell experimental results demonstrated that the number of cells in the experimental group and the control group was (14.2±1.68)×105 and (28.7±2.02)×105 respectively, and the difference was statistically significant (t=3.022, P=0.001). Conclusion CXCL16/CXCR6 may be involved in the proliferation, invasion and metastasis of colon cancer. Key words: CXC chemokine ligand 16; CXC chemokine receptor 6; Colon cancer; Proliferation; Invasion

MicroRNA-449a suppresses liver cancer migration and invasion through targeting CXC chemokine ligand 5

Objective To explore the expression of microRNA (miRNA, miR)-449a in liver cancer, the effect on migration and invasion, and the possible regulatory mechanism. Methods Eighteen cases of liver cancer tissues and adjacent tissues were collected. The expression of miR-449a in liver cancer tissues and adjacent tissues, 4 kinds of human liver cancer cell lines, and human normal hepatocytes was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). The human liver cancer cell lines were transfected with miR-449a mimic and the negative control (NC) plasmid. The expression of miR-449a after transfection was detected by RT-PCR. The cell number of invasion and migration after transfection in the two groups was measured by Transwell assays. The expression of CXC chemokine ligand 5 (CXCL5) protein in the cells was detected by Western blotting. Results As compared with the adjacent tissues, the expression of miR-449a in liver cancer tissues was significantly reduced (0.957±0.165 vs. 0.462±0.221, t=4.137, P=0.021). As compared with the human normal hepatocytes, the expression of miR-449a in four kinds of human liver cancer cell lines was significantly reduced too (P=0.009, 0.008, 0.005, 0.020), the difference being statistically significant (BEL-7402: 6.873±1.293, HepG2: 7.246±1.320, NC: 1.000, P=0.012, 0.017). Two kinds of human liver cancer cell lines with the middle expression of miR-449a were chosen, and the expression of miR-449a after transfection was statistically increased, and the cell number of invasion (BEL-7402 vs. NC: 21.57±13.32 vs. 79.84±11.68; HepG2 vs. NC: 45.32±12.65 vs. 92.21±15.43, t=24.331, 21.109, P=0.011, 0.019) and migration (BEL-7402 vs. NC: 10.25±3.21 vs. 26.63±6.48; HepG2 vs. NC: 23.44±10.08 vs. 65.65±12.26, t=11.039, 12.224, P=0.010, 0.008) after transfection was significantly reduced. The expression of CXCL5 protein after transfection was statistically significantly reduced (BEL-7402 vs. NC: 0.367±0.083 vs. 0.965±0.110; HepG2 vs. NC: 0.163±0.043 vs. 0.949±0.141, t=20.176, 25.158) (P=0.021, 0.016). Conclusion The miR-449a in liver cancer is expressed weakly, and can serve as a tumor suppressor to influence the migration and invasion of liver cancer cells through targeting CXCL5. Key words: MicroRNA-449a; CXC chemokine ligand 5; Liver cancer; Migration; Invasion

The effects of glycyrrhizic acid and glabridin in the regulation of CXCL5 inflammation gene on acceleration of wound healing

ObjectiveTo evaluate the anti-inflammatory property of both glycyrrhizic acid (GA) and glabridin in reducing inflammation to accelerate wound regeneration on 3T3-L1 and NIH-3T3 fibroblast cell lines. MethodsCell proliferation and viability assay (MTT assay), scratch wound healing assays, and quantitative real-time PCR were conducted to investigate the effects on cell proliferation, cell migration, and expression of CXC chemokine ligand 5 inflammation gene respectively. ResultsResults showed that at a low concentration of 1 × 10−8 mol/L, glabridin down regulated cell proliferation in NIH-3T3 significantly, suggesting its involvement in ERK1/2 signaling pathway. GA and glabridin significantly accelerated cell migration through wound healing in both 3T3-L1 and NIH-3T3 and significantly down regulated the expression of CXC chemokine ligand 5 in 3T3-L1 at concentration 1 × 10−8 mol/L, indicating the possible involvement of nuclear factor-κB and cyclooxygenase 2 transcriptions modulation. ConclusionsBoth GA and glabridin can serve as potential treatment for chronic inflammatory disease, and glabridin as an oncogenic inhibitor due to its anti-proliferative property.

CXCR4 Inhibition Ameliorates Severe Obliterative Pulmonary Hypertension and Accumulation of C-Kit+ Cells in Rats

Successful curative treatment of severe pulmonary arterial hypertension with luminal obliteration will require a thorough understanding of the mechanism underlying the development and progression of pulmonary vascular lesions. But the cells that obliterate the pulmonary arterial lumen in severe pulmonary arterial hypertension are incompletely characterized. The goal of our study was to evaluate whether inhibition of CXC chemokine receptor 4 will prevent the accumulation of c-kit+ cells and severe pulmonary arterial hypertension. We detected c-kit+­ cells expressing endothelial (von Willebrand Factor) or smooth muscle cell/myofibroblast (α-smooth muscle actin) markers in pulmonary arterial lesions of SU5416/chronic hypoxia rats. We found increased expression of CXC chemokine ligand 12 in the lung tissue of SU5416/chronic hypoxia rats. In our prevention study, AMD3100, an inhibitor of the CXC chemokine ligand 12 receptor, CXC chemokine receptor 4, only moderately decreased pulmonary arterial obliteration and pulmonary hypertension in SU5416/chronic hypoxia animals. AMD3100 treatment reduced the number of proliferating c-kit+ α-smooth muscle actin+ cells and pulmonary arterial muscularization and did not affect c-kit+ von Willebrand Factor+ cell numbers. Both c-kit+ cell types expressed CXC chemokine receptor 4. In conclusion, our data demonstrate that in the SU5416/chronic hypoxia model of severe pulmonary hypertension, the CXC chemokine receptor 4-expressing c-kit+ α-smooth muscle actin+ cells contribute to pulmonary arterial muscularization. In contrast, vascular lumen obliteration by c-kit+ von Willebrand Factor+ cells is largely independent of CXC chemokine receptor 4.

Role and clinicopathologic significance of CXC chemokine ligand 16 and chemokine (C-X-C motif) receptor 6 expression in gastric carcinomas

The chemokine ligand CXC chemokine ligand 16 and its receptor chemokine (C-X-C motif) receptor 6 are up-regulated in many types of cancer and give rise to more aggressive behavior by regulating proliferation and angiogenesis. To clarify the role and clinicopathologic significance of CXC chemokine ligand 16 and chemokine (C-X-C motif) receptor 6 expression in gastric carcinoma, their expression was examined by immunohistochemistry of tissue microarrays containing gastric carcinoma and nonneoplastic mucosa, reverse transcription-polymerase chain reaction, and Western blotting and by enzyme-linked immunosorbent assay to determine the CXC chemokine ligand 16 concentration in serum. Expression was compared with the clinicopathologic features of the carcinomas. All carcinoma and epithelial cells showed CXC chemokine ligand 16 and chemokine (C-X-C motif) receptor 6 messenger RNA expression to various degrees. Among 28 pairs of gastric carcinoma and normal tissues, there was higher CXC chemokine ligand 16 expression in carcinoma than in adjacent mucosa (P < .05), whereas the converse was true for chemokine (C-X-C motif) receptor 6 (P < .05). Nuclear CXC chemokine ligand 16 expression correlated inversely with the depth of invasion, lymphatic invasion, Union Internationale Contre le Cancer stage, and favorable prognosis. The serum CXC chemokine ligand 16 concentration was lower in male patients or patients 55 years or older than in female or younger patients, respectively (P < .05). Patients with lymphatic invasion or mixed-type carcinoma showed lower CXC chemokine ligand 16 concentrations than those with no lymphatic invasion or with diffuse-type carcinoma (P < .05). Aberrant expression of CXC chemokine ligand 16 and chemokine (C-X-C motif) receptor 6 might be involved in gastric carcinogenesis. The expression and serum concentration of CXC chemokine ligand 16 could indicate the aggressiveness and prognosis of gastric carcinomas.

The role of melanoma tumor‐derived nitric oxide in the tumor inflammatory microenvironment: Its impact on the chemokine expression profile, including suppression of CXCL10

Melanoma appears to be heterogeneous in terms of its molecular biology, etiology and epidemiology. We previously reported that the expression of inducible nitric-oxide synthase (iNOS) in melanoma tumor cells is strongly correlated with poor patient survival. Therefore, we hypothesized that nitric oxide (NO) produced by iNOS promotes the melanoma inflammatory tumor microenvironment associated with poor outcome. To understand the role of NO and iNOS in the melanoma inflammatory tumor microenvironment, polymerase chain reaction arrays of inflammatory and autoimmunity genes were performed on a series of stage III melanoma lymph node metastasis samples to compare the gene expression profiles of iNOS-expressing and nonexpressing tumor samples. The results indicate that expression of CXC chemokine ligand 10 (CXCL10) was inversely correlated with iNOS expression, and the high CXCL10-expressing cases had more favorable prognoses than the low CXCL10-expressing cases. Functional studies revealed that treating iNOS-negative/CXCL10-positive melanoma cell lines with a NO donor suppressed the expression of CXCL10. Furthermore, scavenging NO from iNOS-expressing cell lines significantly affected the chemokine expression profile. Culture supernatants from NO scavenger-treated melanoma cells promoted the migration of plasmacytoid dendritic cells, which was diminished when the cells were treated with a CXCL10-neutralizing antibody. CXCL10 has been reported to be an antitumorigenic chemokine. Our study suggests that the production of NO by iNOS inhibits the expression of CXCL10 in melanoma cells and leads to a protumorigenic tumor microenvironment. Inhibiting NO induces an antitumorigenic environment, and thus, iNOS should be considered to be an important therapeutic target in melanoma.

Effects of aliskiren on stroke in rats expressing human renin and angiotensinogen genes.

ObjectivePre-treatment with angiotensin receptor blockers is known to improve neurological outcome after stroke. This study investigated for the first time, whether the renin inhibitor aliskiren has similar neuroprotective effects.MethodsSince aliskiren specifically blocks human renin, double transgenic rats expressing human renin and angiotensinogen genes were used. To achieve a systolic blood pressure of 150 or 130 mmHg animals were treated with aliskiren (7.5 or 12.5 mg/kg*d) or candesartan (1.5 or 10 mg/kg*d) via osmotic minipump starting five days before middle cerebral artery occlusion with reperfusion. Infarct size was determined by magnetic resonance imaging. mRNA of inflammatory marker genes was studied in different brain regions.ResultsThe mortality of 33.3% (7 of 21 animals) in the vehicle group was reduced to below 10% by treatment with candesartan or aliskiren (p<0.05). Aliskiren-treated animals had a better neurological outcome 7 days post-ischemia, compared to candesartan (Garcia scale: 9.9±0.7 vs. 7.3±0.7; p<0.05). The reduction of infarct size in the aliskiren group did not reach statistical significance compared to candesartan and vehicle (24 h post-ischemia: 314±81 vs. 377±70 and 403±70 mm3 respectively). Only aliskiren was able to significantly reduce stroke-induced gene expression of CXC chemokine ligand 1, interleukin-6 and tumor necrosis factor-alpha in the ischemic core.ConclusionsHead-to-head comparison suggests that treatment with aliskiren before and during cerebral ischemia is at least as effective as candesartan in double transgenic rats. The improved neurological outcome in the aliskiren group was blood pressure independent. Whether this effect is due to primary anti-inflammatory mechanisms has to be investigated further.

Contribution of bone microenvironment to leukemogenesis and leukemia progression

Tumor microenvironment has a major role in cancer progression and resistance to treatment. The bone marrow (BM) is a dynamic network of growth factors, cytokines and stromal cells, providing a permissive environment for leukemogenesis and progression. Both BM stroma and leukemic blasts promote angiogenesis, which is increased in acute lymphoblastic leukemia and acute myeloid leukemia. Growth factors like vascular endothelial growth factor (VEGF), basic fibroblast growth factor and angiopoietins are the main proangiogenic mediators in acute leukemia. Autocrine proleukemic loops have been described for VEGF and angiopoietin in hematopoietic cells. Interactions of stromal cells and extracellular matrix with leukemic blasts can also generate antiapoptotic signals that contribute to neoplastic progression and persistence of treatment-resistant minimal residual disease. High expression of CXC chemokine ligand 4 (CXCR4) by leukemic blasts and activation of the CXCR4-CXCL12 axis is involved in leukemia progression and disruption of normal hematopoiesis. Leukemia-associated bone microenvironment markers could be used as prognostic or predictive indicators of disease progression and/or treatment outcome. Studies related to bone microenvironment would likely provide a better understanding of the treatment resistance associated with leukemia therapy and design of new treatments.

CXCL10 and trafficking of virus-specific T cells during coronavirus-induced demyelination

Chronic expression of CXC chemokine ligand 10 (CXCL10) in the central nervous system (CNS) following infection with the neurotropic JHM strain of mouse hepatitis virus (JHMV) is associated with an immune-mediated demyelinating disease. Treatment of mice with anti-CXCL10 neutralizing antibody results in limited CD4+ T cell infiltration into the CNS accompanied by a reduction in white matter damage. The current study determines the antigen-specificity of the T lymphocytes present during chronic disease and evaluates how blocking CXCL10 signaling affects retention of virus-specific T cells within the CNS. CXCL10 neutralization selectively reduced accumulation and/or retention of virus-specific CD4+ T cells, yet exhibited limited effect on virus-specific CD8+ T cells. The response of CXCL10 neutralization on virus-specific T cell subsets is not due to differential expression of the CXCL10 receptor CXCR3 on T cells as there was no appreciable difference in receptor expression on virus-specific T cells during either acute or chronic disease. These findings emphasize the importance of virus-specific CD4+ T cells in amplifying demyelination in JHMV-infected mice. In addition, differential signals are required for trafficking and retention of virus-specific CD4+ and CD8+ T cells during chronic demyelination in JHMV-infected mice.

Upregulated monocytic expression of CXC chemokine ligand 10 (CXCL-10) and its relationship with serum interleukin-6 levels in the syndrome of frailty

Frailty is an important geriatric syndrome that predicts disability and mortality. Substantial evidence suggests inflammation marked by elevated IL-6 levels as a key pathophysiologic factor that contributes to frailty. CXCL-10, a potent pro-inflammatory chemokine, has increased levels with age and is implicated in several inflammatory conditions. To better understand molecular mechanisms of inflammation activation in frailty, we evaluated monocytic expression of CXCL-10 and other inflammatory pathway genes by pathway-specific gene array analysis and quantitative RT-PCR. Frailty status was determined by the validated criteria. Sixteen pairs of community-dwelling frail and age-, race-, and sex-matched non-frail participants (mean age 83 years, range 72–94) completed the study. Here we report that frail participants had higher CXCL-10 expression levels than matched non-frail controls (1.05 ± 0.88 versus 0.53 ± 0.39, p = 0.04). CXCL-10 expression correlated with IL-6 levels only in frail participants (Spearman correlation coefficient r = 0.52, p = 0.03). Furthermore, frailty-associated CXCL-10 upregulation was highly correlated with IL-6 elevation, both measured by frail-over-non-frail ratios ( r = 0.93, p < 0.0001). These findings suggest upregulated monocytic expression of CXCL-10 as an important molecular mechanism that contributes to inflammation activation in frail older adults. Therapeutic implications include potential development of CXCL-10-based interventional strategies for the prevention and treatment of frailty in older adults.

Altered expression of the receptor-ligand pair CXCR5/CXCL13 in B cells during chronic HIV-1 infection

AbstractHIV-1 infection is associated with B-cell abnormalities, such as hypergammaglobulinemia, poor immunization responses, and loss of serologic memory. To determine whether altered expression of chemokine receptors and their ligands may play a role in B-cell dysfunctions during HIV-1 infection, the expression of CXC chemokine receptor 4 (CXCR4), CXCR5, and CC chemokine receptor 7 (CCR7) and their respective ligands on CD19+ B cells were examined in HIV-1–infected patients and controls. We report a decreased CXCR5 expression on B cells from patients (P < .05), a phenomenon associated with a low CD4 T-cell count (< 350 cells/μL). Interestingly, an increased expression of CXC chemokine ligand 13 (CXCL13), the ligand for CXCR5, was found in peripheral B cells from HIV-1–infected patients. Moreover, on B-cell activation in vitro, CXCL13 was secreted in culture. CXCL13+ B cells were also found in the lymph nodes of HIV-1–infected patients, but not in control tissue. B-cell migration toward CXCL13, CXCL12, and CC chemokine ligand 21 (CCL21), ligands for CXCR5, CXCR4, and CCR7 was also evaluated. In patients with a low CD4 T-cell count, migration toward all ligands was increased. Our findings indicate that altered expression of the chemokine receptor-ligand pair, CXCR5/CXCL13, may participate in the establishment of B-cell dysfunctions during HIV-1 infection.

Expression of CXC Chemokine Ligand 10 from the Mouse Hepatitis Virus Genome Results in Protection from Viral-Induced Neurological and Liver Disease

Using the recombinant murine coronavirus mouse hepatitis virus (MHV) expressing the T cell-chemoattractant CXCL10 (MHV-CXCL10), we demonstrate a potent antiviral role for CXCL10 in host defense. Instillation of MHV-CXCL10 into the CNS of CXCL10-deficient (CXCL10(-/-)) mice resulted in viral infection and replication in both brain and liver. Expression of virally encoded CXCL10 within the brain protected mice from death and correlated with increased infiltration of T lymphocytes, enhanced IFN-gamma secretion, and accelerated viral clearance when compared with mice infected with an isogenic control virus, MHV. Similarly, viral clearance from the livers of MHV-CXCL10-infected mice was accelerated in comparison to MHV-infected mice, yet was independent of enhanced infiltration of T lymphocytes and NK cells. Moreover, CXCL10(-/-) mice infected with MHV-CXCL10 were protected from severe hepatitis as evidenced by reduced pathology and serum alanine aminotransferase levels compared with MHV-infected mice. CXCL10-mediated protection within the liver was not dependent on CXC-chemokine receptor 2 (CXCR2) signaling as anti-CXCR2 treatment of MHV-CXCL10-infected mice did not modulate viral clearance or liver pathology. In contrast, treatment of MHV-CXCL10-infected CXCL10(-/-) mice with anti-CXCL10 Ab resulted in increased clinical disease correlating with enhanced viral recovery from the brain and liver as well as increased serum alanine aminotransferase levels. These studies highlight that CXCL10 expression promotes protection from coronavirus-induced neurological and liver disease.