Key role of chemokines and chemokine receptors in inflammation, immunity, neoplasia, and infectious disease

Chemokine Ligands and Receptors Regulate Macrophage Polarization in Atherosclerosis: A Comprehensive Database Mining Study

Background

Atherosclerosis is a systemic disease involving multiple blood vessels and a major cause of cardiovascular disease. Current treatment methods (eg, statins) for atherosclerosis can reduce the risk of cardiovascular diseases effectively, but they are insufficient to completely reverse existing atherosclerosis. Macrophages play a central role in development of atherosclerosis. Chemokines, the main mediators of macrophage chemotaxis, are important in immune and inflammatory responses. The effects of chemokines on mechanisms involved in atherosclerosis are unknown. This study preliminarily investigated these effects and mechanisms via bioinformatics methods.

Methods

In this study, data on chemokine ligands and receptors were obtained by mining public databases (the National Center of Biotechnology Information-Gene Expression Omnibus [NCBI-GEO] database, ArrayExpress database, and single-cell RNA sequencing [scRNA-seq] database), and an extensive literature search was performed. The expression levels of chemokines in mouse tissues were analyzed via Metascape software for signalling pathway enrichment, scRNA-seq data for chemokine expression in atherosclerotic plaque progression and regression, and GEO2R data for chemokine expression during macrophage polarization. Ingenuity Pathway Analysis (IPA) software was used to analyze regulatory factors such as transcription factors and microRNAs that are significantly differentially expressed upstream of chemokines in macrophage polarization. Finally, a model of the chemokine regulation of atherosclerosis was established on the basis of these results.

Results

There are 5 main findings: (1) In atherosclerosis, chemokines are regulated by transcription factors and microRNAs. (2) The transcription factor STAT1 promotes the polarization of dormant (M0) macrophages into classically activated (M1) macrophages and alternative activated (M2) macrophages by regulating chemokines. The transcription factors STAT1, IRF7 and IRF1 regulate the polarization of M0 macrophages into M2a and M2b macrophages via different chemokines. For example, some transcription factors promote M1 polarization of M0 macrophages through CCL4, but M2 macrophage polarization is regulated via CCL19, CCL5 and CCR7. (3) Transcription factors can promote and inhibit, whereas miRNAs can only inhibit atherosclerosis. (4) CCL4 existed in all 5 different chemokine-regulated macrophage models, whereas CXCL3 only existed in the M2b macrophage transcriptional regulation model, indicating that CXCL3 may promote the M2b type macrophages polarization of M0 macrophages. (5) CCL5 and CCR7 can promote the M2a macrophages and M2b macrophages polarization of M0 macrophages.

Conclusions

Atherosclerosis can be treated by regulating chemokines and regulating the polarization of macrophages. The chemokines CCL4, CCL5, CCL8, CCL19, CXCL3, CXCL10, CXCL13, and CCR7 may play key roles in the progression and regression of atherosclerosis.

Lung Macrophage Functional Properties in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is caused by the chronic exposure of the lungs to toxic particles and gases. These exposures initiate a persistent innate and adaptive immune inflammatory response in the airways and lung tissues. Lung macrophages (LMs) are key innate immune effector cells that identify, engulf, and destroy pathogens and process inhaled particles, including cigarette smoke and particulate matter (PM), the main environmental triggers for COPD. The number of LMs in lung tissues and airspaces is increased in COPD, suggesting a potential key role for LMs in initiating and perpetuating the chronic inflammatory response that underpins the progressive nature of COPD. The purpose of this brief review is to discuss the origins of LMs, their functional properties (chemotaxis, recruitment, mediator production, phagocytosis and apoptosis) and changes in these properties due to exposure to cigarette smoke, ambient particulate and pathogens, as well as their persistent altered functional properties in subjects with established COPD. We also explore the potential to therapeutically modulate and restore LMs functional properties, to improve impaired immune system, prevent the progression of lung tissue destruction, and improve both morbidity and mortality related to COPD.

CCR4 Expression Is Associated With Poor Prognosis in Patients With Early Stage (pN0) Oral Tongue Cancer

PURPOSE

Chemokine receptors are involved in tumor metastasis and can predict poor prognosis; however, the expression and clinicopathologic relevance of chemokine receptors in early-stage cancer remain largely unknown. This study measured the association between chemokine (C-C motif) receptor-4 (CCR4) expression and prognosis in patients with histologically node-negative (pN0) oral tongue cancer.

MATERIALS AND METHODS

A retrospective analysis of CCR4 expression data from a consecutive case series of patients with pN0 oral cancer tongue was conducted. The expression of CCR4 by immunohistochemistry was investigated and the association between CCR4 expression and clinicopathologic variables and overall and disease-free survivals was evaluated using Kaplan-Meier analysis and a Cox regression model.

RESULTS

CCR4 expression was examined in 128 human tongue cancerous samples (109 tongue squamous cell carcinomas [TSCCs] and 19 other types) and 10 normal tongue samples and was found to be highly expressed in tumor tissues compared with normal tissues. CCR4 expression was observed in 64.2% of patients with TSCC and showed a significant association with tumor stage (P = .037). Patients with CCR4-positive expression exhibited poorer overall and disease-free survivals compared with those with CCR4-negative expression (P < .001 and P = .001), and CCR4-positive expression was an independent factor of unfavorable overall and disease-free survivals (P = .002 and P = .007).

CONCLUSIONS

This study identified CCR4 as a potential prognostic biomarker for recurrence and survival of patients with pN0 oral tongue cancer. Thus, CCR4 might be a possible therapeutic target for patients with early-stage cancer.

Bioinformatic identification of key genes and pathways that may be involved in the pathogenesis of HBV-associated acute liver failure

In order to explore the molecular mechanisms behind the pathogenesis of acute liver failure (ALF) associated with hepatitis B virus (HBV) infection, the present study aimed to identify potential key genes and pathways involved using samples from patients with HBV-associated ALF. The GSE38941 array dataset was downloaded from the Gene Expression Omnibus database, and differentially expressed genes (DEGs) between 10 liver samples from 10 healthy donors and 17 liver specimens from 4 patients with HBV-associated ALF were analyzed using the Linear Models for Microarray Data package. Gene Ontology and KEGG pathway enrichment analyses of the DEGs were performed, followed by functional annotation of the genes and construction of a protein–protein interaction (PPI) network. Subnetwork modules were subsequently identified and analyzed. In total, 3142 DEGs were identified, of which 1755 were upregulated and 1387 were downregulated. The extracellular exosome, immune response, and inflammatory response pathways may potentially be used as biomarkers of ALF pathogenesis. In total, 17 genes (including CCR5, CXCR4, ALB, C3, VGEFA, and IGF1) were identified as hub genes in the PPI network and may therefore be potential marker genes for HBV-associated ALF.

Potential impact of metal oxide nanoparticles on the immune system: The role of integrins, L-selectin and the chemokine receptor CXCR4

The impact of metal oxide nanoparticles (NPs) on the immune system has been studied in vitro using human peripheral blood lymphocytes (PBLs). Metal oxide NPs (ZnO, CeO2, TiO2 and Al2O3) induced changes in the expression levels of adhesion molecules and the C-X-C chemokine receptor type 4 (CXCR4) in these cells. Proliferation studies were carried out with CFSE in response to PHA, finding an increase in T-cell proliferation upon cell exposure to TiO2 and Al2O3 NPs. For ZnO NPs, a decrease in the chemotactic response to SDF-1α was observed. No changes were found in basophil activation and leukocyte oxidative burst after phagocytosis. Despite the absence of cytotoxicity, metal oxide NPs are not inert; they alter the expression levels of adhesion molecules and chemokine receptors, key actors in the immune response, and affect important cell functions such as T-cell proliferative response to mitogens and chemotaxis.

FROM THE CLINICAL EDITOR

This study demonstrates the immune-modulating effects of four different metal nanoparticles in a human peripheral blood lymphocyte model system. These effects were clearly present even though these nanoparticles did not display cytotocity in ex vivo experiments.

Differentiating Branch Duct and Mixed IPMN in Endoscopically Collected Pancreatic Cyst Fluid via Cytokine Analysis

Background. Differentiating branch duct from mixed intraductal papillary mucinous neoplasm (BD-IPMN) is problematic, but clinically important as mixed IPMNs are managed surgically, while some BD-IPMN may be followed. Inflammatory mediator proteins (IMPs) have been implicated in acute and chronic inflammatory and malignant pancreatic diseases. Aim. To compare IMP profile of pancreatic cyst fluid collected endoscopically from BD-IPMN and mixed IPMN. Methods. Pancreatic cyst fluid from ten patients (5 BD-IPMN and 5 mixed IPMN) was collected by endoscopic ultrasound-guided fine needle aspiration or endoscopic retrograde cholangiopancreatography. Concentrations of 89 IMPs in these samples were determined using a multiplexed bead-based microarray protein assay and compared between BD-IPMN and mixed IPMN. Results. Eighty-six of 89 IMPs were detected in at least one of the 10 samples. Fourteen IMPs were detected only in mixed IPMN, while none were only in BD-IPMN. Of these, TGF-β1 was most prevalent, present in 3 of 5 mixed IPMNs. Seventy-two IMPs were detected in both BD-IPMN and mixed IPMNs. Of these, only G-CSF (P < 0.05) was present in higher concentrations in mixed IPMNs. Conclusion. TGF-β1 and G-CSF detected in endoscopically collected pancreatic cyst fluid are potential diagnostic biomarkers capable of distinguishing mixed IPMN from BD-IPMN.

Common and specific signatures of gene expression and protein-protein interactions in autoimmune diseases

The aim of this study is to understand intracellular regulatory mechanisms in peripheral blood mononuclear cells (PBMCs), which are either common to many autoimmune diseases or specific to some of them. We incorporated large-scale data such as protein-protein interactions, gene expression and demographical information of hundreds of patients and healthy subjects, related to six autoimmune diseases with available large-scale gene expression measurements: multiple sclerosis (MS), systemic lupus erythematosus (SLE), juvenile rheumatoid arthritis (JRA), Crohn's disease (CD), ulcerative colitis (UC) and type 1 diabetes (T1D). These data were analyzed concurrently by statistical and systems biology approaches tailored for this purpose. We found that chemokines such as CXCL1-3, 5, 6 and the interleukin (IL) IL8 tend to be differentially expressed in PBMCs of patients with the analyzed autoimmune diseases. In addition, the anti-apoptotic gene BCL3, interferon-γ (IFNG), and the vitamin D receptor (VDR) gene physically interact with significantly many genes that tend to be differentially expressed in PBMCs of patients with the analyzed autoimmune diseases. In general, similar cellular processes tend to be differentially expressed in PBMC in the analyzed autoimmune diseases. Specifically, the cellular processes related to cell proliferation (for example, epidermal growth factor, platelet-derived growth factor, nuclear factor-κB, Wnt/β-catenin signaling, stress-activated protein kinase c-Jun NH2-terminal kinase), inflammatory response (for example, interleukins IL2 and IL6, the cytokine granulocyte-macrophage colony-stimulating factor and the B-cell receptor), general signaling cascades (for example, mitogen-activated protein kinase, extracellular signal-regulated kinase, p38 and TRK) and apoptosis are activated in most of the analyzed autoimmune diseases. However, our results suggest that in each of the analyzed diseases, apoptosis and chemotaxis are activated via different subsignaling pathways. Analyses of the expression levels of dozens of genes and the protein-protein interactions among them demonstrated that CD and UC have relatively similar gene expression signatures, whereas the gene expression signatures of T1D and JRA relatively differ from the signatures of the other autoimmune diseases. These diseases are the only ones activated via the Fcɛ pathway. The relevant genes and pathways reported in this study are discussed at length, and may be helpful in the diagnoses and understanding of autoimmunity and/or specific autoimmune diseases.

Inflammatory protein profiling of pancreatic cyst fluid using EUS-FNA in tandem with cytokine microarray differentiates between branch duct IPMN and inflammatory cysts

BACKGROUND

Diagnosis of pancreatic cystic neoplasms remains problematic. We hypothesize that inflammatory mediator proteins in pancreatic cyst fluid can differentiate branch duct intraductal papillary mucinous neoplasms (BD-IPMNs) and pancreatic inflammatory cysts. We aim to 1) detect inflammatory mediator proteins (IMPs) using a multiplexed IMP-targeted microarray in pancreatic cyst fluid obtained during endoscopic ultrasound fine needle aspiration (EUS-FNA) and 2) compare IMP profiles in pancreatic cyst fluid from BD-IPMNs and inflammatory cysts. Pancreatic cyst fluid from ten patients (5 BD-IPMN and 5 inflammatory cysts) was obtained by EUS-FNA and analyzed directly with a multiplexed microarray assay to determine concentrations of 89 IMPs. Statistical analysis was performed using non-parametric methods.

RESULTS

Eighty-three of the 89 assayed IMPs were detected in at least one of the 10 patient samples. Seven IMPs were detected in BD-IPMN but not inflammatory cysts, while eleven IMPs were identified in inflammatory cysts but not BD-IPMN. Notably, granulocyte-macrophage colony-stimulating factor (GM-CSF) expression was present in all five inflammatory cyst samples. Hepatocyte growth factor (HGF) was present in significantly higher concentrations in inflammatory cysts compared to BD-IPMN.

CONCLUSION

Our exploratory analysis reveals that GM-CSF and HGF in EUS-FNA-collected pancreatic cyst fluid can distinguish between BD-IPMN and inflammatory cyst. Coupling microarray molecular techniques to EUS-FNA may represent a major step forward to our understanding complex pancreatic disease.

Cytokine profiling of pancreatic fluid using the ePFT collection method in tandem with a multiplexed microarray assay

Cytokines are secreted immunomodulating proteins involved in pancreatic stellate cell activation and propagation of fibrosis in chronic pancreatitis. We aim to show that cytokines can be identified from pancreatic fluid by (1) collecting pancreatic fluid with the ePFT method, (2) processing the fluid for cytokine-targeted microarray analysis, and (3) comparing cytokine profiles in pancreatic fluid of chronic pancreatitis (CP) patients and of chronic abdominal pain (CAP) controls. We endoscopically collected pancreatic fluid from patients with CP and those with CAP using the ePFT method. This fluid was subjected directly to a multiplexed cytokine protein microarray assay. Six patients (3 CP, 3 CAP) underwent a secretin-stimulated ePFT. The mean peak bicarbonate concentrations [meq/L] of the CP and CAP patients were 43 and 97, respectively. Statistically significant decreases in the cytokine concentrations of EGF, IP-10, eotaxin, IL-3, MIP-1a, IL-15, PDGF-AB/BB, and IL-1a were observed in the CP specimens (p<0.05). We have successfully identified differences in the abundance of cytokines in ePFT-collected pancreatic fluid with a multiplexed microarray assay comparing CP and CAP controls. Further targeted investigation of cytokines in ePFT-collected fluid will broaden our knowledge of pancreatic immune response and pathogenesis in chronic pancreatitis.

Effects of orthopedic polymer particles on chemotaxis of macrophages and mesenchymal stem cells

Wear particles generated from total joint arthroplasty (TJA) stimulate macrophages to release chemokines. The role of chemokines released from wear particle-stimulated macrophages on the migration of macrophages and osteoprogenitor cells in vitro has not been elucidated. In this study, we challenged murine macrophages (RAW 264.7) with clinically relevant polymethyl methacrylate (PMMA, 1-10 microm) and ultra high molecular weight polyethylene (UHMWPE, 2-3 microm) particles. The chemotactic effects of the conditioned media (CM) were tested in vitro using human macrophages (THP-1) and human mesenchymal stem cells (MSCs) as the migrating cells. CM collected from both particle types had a chemotactic effect on human macrophages, which could be eliminated by monocyte chemotactic protein-1 (MCP-1) neutralizing antibody. Blocking the CCR1 receptor eliminated the chemotactic effect, while CCR2 antibody only partially decreased THP-1 cell migration. CM from PMMA but not UHMWPE-exposed macrophages led to chemotaxis of MSCs; this effect could be eliminated by macrophage inflammatory protein-1 alpha (MIP-1alpha) neutralizing antibody. Neither CCR1 nor CCR2 blocking antibodies showed an effect on the migration of MSCs. Chemokines released by macrophages stimulated by wear particles can have an effect on the migration of macrophages and MSCs. This effect seems to be dependent on the particle type, and may be modulated by MCP-1 and MIP-1alpha, however, more than one chemokine may be necessary for chemotaxis.

F-actin-binding protein drebrin regulates CXCR4 recruitment to the immune synapse

The adaptive immune response depends on the interaction of T cells and antigen-presenting cells at the immune synapse. Formation of the immune synapse and the subsequent T-cell activation are highly dependent on the actin cytoskeleton. In this work, we describe that T cells express drebrin, a neuronal actin-binding protein. Drebrin colocalizes with the chemokine receptor CXCR4 and F-actin at the peripheral supramolecular activation cluster in the immune synapse. Drebrin interacts with the cytoplasmic tail of CXCR4 and both proteins redistribute to the immune synapse with similar kinetics. Drebrin knockdown in T cells impairs the redistribution of CXCR4 and inhibits actin polymerization at the immune synapse as well as IL-2 production. Our data indicate that drebrin exerts an unexpected and relevant functional role in T cells during the generation of the immune response.

Immunogenetics of drug-induced skin blistering disorders. Part I: Perspective

The overall immunopathogenesis relevant to a large series of disorders caused by a drug or its associated hyperimmune condition is discussed based upon the examination of the genetics of severe drug-induced bullous skin problems (sporadic idiosyncratic adverse events, including Stevens-Johnson syndrome and toxic epidermal necrolysis). An overarching pharmacogenetic schema is proposed. Immune cognition and early-effector processes are focused upon and a challenging synthesis around systems evolution is explained by a variety of projective analogies. Etiology, human leukocyte antigen-B, immune stability, dysregulation, pharmacomimicry, viruses and an aggressive ethnically differentiated 'karmic' response are discussed.

Future innovations in anti-platelet therapies

Platelets have long been recognized to be of central importance in haemostasis, but their participation in pathological conditions such as thrombosis, atherosclerosis and inflammation is now also well established. The platelet has therefore become a key target in therapies to combat cardiovascular disease. Anti-platelet therapies are used widely, but current approaches lack efficacy in a proportion of patients, and are associated with side effects including problem bleeding. In the last decade, substantial progress has been made in understanding the regulation of platelet function, including the characterization of new ligands, platelet-specific receptors and cell signalling pathways. It is anticipated this progress will impact positively on the future innovations towards more effective and safer anti-platelet agents. In this review, the mechanisms of platelet regulation and current anti-platelet therapies are introduced, and strong, and some more speculative, potential candidate target molecules for future anti-platelet drug development are discussed.

Stromal-derived factor-1alpha (CXCL12) levels increase in periodontal disease

BACKGROUND

The CXC chemokine receptor 4 (CXCR4) and its ligand, stromal cell-derived factor-1 (SDF-1alpha or CXC chemokine ligand 12) are involved in the trafficking of leukocytes into and out of extravascular tissues. The purpose of this study was to determine whether SDF-1alpha secreted by host cells plays a role in recruiting inflammatory cells into the periodontia during local inflammation.

METHODS

SDF-1alpha levels were determined by enzyme-linked immunosorbent assay in gingival crevicular fluid (GCF) of 24 individuals with periodontitis versus healthy individuals in tissue biopsies and in a preclinical rat model of Porphyromonas gingivalis lipopolysaccharide-induced experimental bone loss. Neutrophil chemotaxis assays were also used to evaluate whether SDF-1alpha plays a role in the recruitment of host cells at periodontal lesions.

RESULTS

Subjects with periodontal disease had higher levels of SDF-1alpha in their GCF compared to healthy subjects. Subjects with periodontal disease who underwent mechanical therapy demonstrated decreased levels of SDF-1alpha. Immunohistologic staining showed that SDF-1alpha and CXCR4 levels were elevated in samples obtained from periodontally compromised individuals. Similar results were observed in the rodent model. Neutrophil migration was enhanced in the presence of SDF-1alpha, mimicking immune cell migration in periodontal lesions.

CONCLUSIONS

SDF-1alpha may be involved in the immune defense pathway activated during periodontal disease. Upon the development of diseased tissues, SDF-1alpha levels increase and may recruit host defensive cells into sites of inflammation. These studies suggest that SDF-1alpha may be a useful biomarker for the identification of periodontal disease progression.

Myosin IIA is involved in the endocytosis of CXCR4 induced by SDF-1alpha

Endocytosis of chemokine receptors regulates signal transduction initiated by chemokines, but the molecular mechanisms underlying this process are not fully defined. In this work, we assessed the involvement of the motor protein nonmuscle myosin heavy chain IIA (MIIA) in the endocytosis of CXCR4 induced by SDF-1alpha (also known as CXCL12) in T lymphocytes. Overexpression of the C-terminal half of MIIA inhibited the ligand-induced endocytosis of CXCR4, but not that of transferrin receptor. Targeting MIIA either by silencing its expression with small interfering RNA (siRNA) or by blebbistatin treatment also inhibited endocytosis of CXCR4. Inhibition of endocytosis of CXCR4 by targeting endogenous MIIA resulted in an increased migration of T cells induced by SDF-1alpha, and in the inhibition of the HIV-1-Env antifusogenic activity of this chemokine. Coimmunoprecipitation and protein-protein binding studies demonstrated that MIIA interacts with both the cytoplasmic tail of CXCR4 and beta-arrestin. Moreover, SDF-1alpha promotes a rapid MIIA-beta-arrestin dissociation. Our data reveal a novel role for MIIA in CXCR4 endocytosis, which involves its dynamic association with beta-arrestin and highlights the role of endogenous MIIA as a regulator of CXCR4 internalization and, therefore, the onset of SDF-1alpha signaling.

Sertoli cells initiate testicular innate immune responses through TLR activation

TLRs play a crucial role in early host defense against invading pathogens. In the seminiferous epithelium, Sertoli cells are the somatic nurse cells that mechanically segregate germ cell autoantigens by means of the blood-tubular barrier and create a microenvironment that protects germ cells from both interstitial and ascending invading pathogens. The objective of this study was to examine TLR expression and their functional responses to specific agonists in mouse Sertoli cells. We measured the expression of TLR2, TLR4, TLR5, and TLR6 mRNAs and confirmed by FACS analysis the presence of proteins TLR2 and TLR5 on which we focused our study. Stimulation of Sertoli cells with macrophage-activating lipopeptide-2, agonist of TLR2/TLR6, and with flagellin, agonist of TLR5, induces augmented secretion of the chemokine MCP-1. To assess the functional significance of MCP-1 production following TLR stimulation, conditioned medium from either macrophage-activating lipopeptide-2 or flagellin-treated Sertoli cells was tested for in vitro chemotaxis assay, and a significant increase of macrophage migration was observed in comparison with unstimulated conditioned medium. Moreover, we studied the role of NF-kappaB and of MAPKs in regulating TLR-mediated MCP-1 secretion by using inhibitors specific for each transduction pathway and we demonstrated a pivotal role of the IkappaB/NF-kappaB and JNK systems. In addition, TLR2/TLR6 and TLR5 stimulation induces increased ICAM-1 expression in Sertoli cells. Collectively, this study demonstrates the novel ability of Sertoli cells to potentially respond to a wide variety of bacteria through TLR stimulation.

Quantitation of ovine cytokine mRNA by real-time RT–PCR

In this study we describe for the first time the dynamics of the expression of the cytokines, IL-1beta, IL-12p40, TNFalpha in ovine dendritic cells and macrophages after LPS stimulation. Real time RT-PCR was used for the quantitation of these cytokines and IL-4 and IFNgamma as well as two potential housekeeping genes (HKG), ATPase and GAPDH, in mRNAs from ovine leucocyte populations. Both dual-labelled probes (TAMRA/FAM) and SYBR Green assays were utilised, using a Corbett Research RotorGene and ABI 7700 machine. In order to quantitate each cytokine in our assays all C(T) values were compared to a standard curve generated using plasmid DNA containing the cytokine of interest. To validate our assays, concanavalin A-stimulated peripheral blood mononuclear cells (PBMCs) and LPS-stimulated monocyte-derived dendritic cells (MoDC) and monocyte-derived macrophages (MDMØ) were examined. We found that peak cytokine mRNA expression was between 3 and 6 h for the cytokines examined except for IL-12p40 where peak cytokine release was around 12 h post-stimulation in MDMØ and PBMCs. However, in MoDCs, peak IL-12p40 mRNA expression was observed within 3-6 h. We have identified a sensitive and reliable method for the identification of ovine cytokine mRNAs.

Tumor-cell homing to lymph nodes and bone marrow and CXCR4 expression in esophageal cancer

BACKGROUND

The chemokine and bone marrow-homing receptor CXCR4 has been implicated in metastatic dissemination of various cancers. We investigated CXCR4 expression in esophageal cancer specimens and its association with survival, lymph node microinvolvement, and bone marrow micrometastasis.

METHODS

We analyzed frozen tumor specimens from 136 patients with completely resected esophageal cancer for CXCR4 expression by immunohistochemistry. Lymph node microinvolvement and bone marrow micrometastasis were assessed by immunohistochemistry with monoclonal antibodies Ber-EP4 (against epithelial cell adhesion molecule) and pancytokeratin A45-B/B3 (against several cytokeratins), respectively. Associations between CXCR4 expression and clinicopathologic features, including tumor stage, histologic grade, lymph node metastasis and microinvolvement, bone marrow micrometastasis, and survival, were investigated with Fisher's test, log-rank test, and Cox multivariable analysis. All statistical tests were two-sided.

RESULTS

CXCR4 protein was expressed in 75 (55%) of 136 esophageal tumors examined. CXCR4 expression was statistically significantly associated with reduced median overall and disease-specific survival, compared with CXCR4 nonexpression (P < .001; log-rank test). The median overall survival of patients with CXCR4-positive tumors was 20 months and with CXCR4-negative tumors, 76 months (difference = 56 months, 95% confidence interval [CI] = 4 to 108 months; P < .001). The median disease-specific survival of patients with CXCR4-positive tumors was 25 months and with CXCR4-negative tumors was 97 months (difference = 72 months, 95% CI = 34 to 110 months; P < .001). CXCR4 expression was statistically significantly associated with increased lymph node microinvolvement (P < .001) and with increased bone marrow micrometastasis (P < .001). In multivariable analysis, CXCR4 expression, compared with its nonexpression, was identified as the independent variable that was most strongly associated with reduced disease-specific survival (relative risk [RR] of death = 2.03, 95% CI = 1.20 to 3.41; P = .008) and overall survival (RR of death = 2.18, 95% CI = 1.33 to 3.59; P = .002).

CONCLUSION

CXCR4 expression was associated with poor clinical outcome in esophageal cancer patients. CXCR4 may have a role in early metastatic spread because its expression was associated with micrometastases to both the lymph nodes and bone marrow. Thus, CXCR4 should be explored further as a target for adjuvant therapy for micrometastatic disease.

Simian immunodeficiency virus disrupts extended lengths of the blood-brain barrier

It is known that there is disruption of the blood-brain barrier during terminal AIDS encephalitis in both human immunodeficiency virus (HIV)-infected humans and simian immunodeficiency virus (SIV)-infected rhesus macaques. Much, although by no means all, of the neuropathological findings of HIV and SIV infection involves accumulation of monocytes/macrophages that have likely crossed the blood-brain barrier (BBB). There is no convincing, rigorous, demonstration of HIV (or SIV) infecting endothelial cells in vivo. However, this is not to say that HIV infection would not have any effects on the physiology of microvascular brain endothelial cells. Because of the elaborate nature of cerebral microvessels, previous studies of cerebral endothelial cells have been constrained by sectioning artifacts. Examination of freshly isolated cerebral microvessels allows investigation of extended lengths of vessels (>150 mum) without sectioning artifacts. These studies determine the changes in the expression of the tight junction protein zo-1 protein on the endothelial cells of cerebral capillaries at terminal acquired immune deficiency syndrome, demonstrating that there is a decreased expression of zo-1 protein over extended lengths of microvessels.

Chemokines derived from soluble fusion proteins expressed in Escherichia coli are biologically active

Chemokines are a class of low molecular weight proteins that are involved in leukocytes trafficking. Due to their involvement in recruiting immune cells to sites of inflammation, chemokines, and chemokine receptors have become an attractive class of therapeutic targets. However, when expressed in Escherichia coli chemokines are poorly soluble and accumulate in inclusion bodies. Several purification methods have been described but involve time-consuming refolding, buffer exchange, and purification steps that complicate expression of these proteins. Here, we describe a simple and reliable method to express chemokines as fusions to the protein NusA. The fusion proteins were largely found in the soluble fraction and could be readily purified in a single step. Proteolytic cleavage was used to obtain soluble recombinant chemokines that were found to be very active in a novel in vitro chemotaxis assays. This method could be applied to several alpha and beta human chemokines, suggesting that it is generally applicable to this class of proteins.

Monocyte chemoattractant protein-1 (MCP-1/CCL2) in experimental autoimmune orchitis

Experimental autoimmune orchitis (EAO) is characterized by an interstitial mononuclear cell infiltrate and a severe lesion of seminiferous tubules with germ cells that undergo apoptosis and sloughing. The mechanism by which immune cells migrate and extravasate in the testicular interstitium is poorly understood. The aim of this study was to detect the variations in the expression of monocyte chemoattractant protein-1 (MCP-1/CCL2) and its receptor in the testis of rats undergoing autoimmune orchitis. EAO was induced in Sprague-Dawley adult rats by active immunization with an emulsion of testicular homogenate and complete Freund adjuvant using Bordetella pertussis as co-adjuvant. Control rats injected with saline and adjuvants and normal untreated rats were also studied. By ELISA we observed a significant increase of MCP-1 in the testicular fluid (TF) and in the conditioned medium obtained from cultures of testicular macrophages of rats with EAO compared with control groups. By immunohistochemistry, an increase in MCP-1 expression was observed in mononuclear, endothelial, Leydig and peritubular cells. MCP-1 immunoreactivity was also detected in Sertoli cell cytoplasm of rats with severe orchitis. A 2-fold increase in the number of mononuclear cells that express CCR2 was also found in rats with orchitis compared with controls. In conclusion, we demonstrated in vivo that MCP-1 is highly expressed in testicular interstitial cells suggesting that this chemokine has an important role in recruiting immune cells to the testis in rats undergoing autoimmune orchitis.

Expression of CXCR4 and CXCL12 (SDF-1) in human prostate cancers (PCa) in vivo

Human prostate cancers (PCa) express great variability in their ability to metastasize to bone. The identification of molecules associated with aggressive phenotypes will help to define PCa subsets and will ultimately lead to better treatment strategies. The chemokine stromal-derived factor-1 (SDF-1 or CXCL12) and its receptor CXCR4 are now known to modulate the migration and survival of an increasing array of normal and malignant cell types including breast, pancreatic cancers, glioblastomas, and others. The present investigation extends our previous investigations by determining the expression of CXCR4 and CXCL12 in humans using high-density tissue microarrays constructed from clinical samples obtained from a cohort of over 600 patients. These data demonstrate that CXCR4 protein expression is significantly elevated in localized and metastastic cancers. At the RNA level, human PCa tumors also express CXCR4 and message, but overall, they were not significantly different suggesting post-transcriptional regulation of the receptor plays a major role in regulating protein expression. Similar observations were made for CXCL12 message, but in this case more CXCL12 message was expressed by metastastic lesions as compared to normal tissues. PCa cell lines also express CXCL12 mRNA, and regulate mRNA expression in response to CXCL12 and secrete biologically active protein. Furthermore, neutralizing antibody to CXCL12 decreased the proliferation of bone homing LNCaP C4-2B and PC3 metastastic tumor cells. These investigations provide important new information pertaining to the molecular basis of how tumors may 'home' to bone, and the mechanisms that may account for their growth in selected end organs.

Cytokine and chemokine responses underlying acute and chronic Trichuris muris infection

Intestinal nematode parasites are some of the most prevalent infections of man. Infections tend to be chronic and, after drug treatment, have high reinfection rates. Control programs relying solely on drugs are thus at best short-term solutions; immunization programs are our long-term goal. A prerequisite to effective disease control by immunotherapy is the need to understand the immune responses that underlie resistance and susceptibility to infection. Most of our current understanding of immunity to Trichuris trichiura infection in man has come from the laboratory model, Trichuris muris in the mouse. Over the last decade we have learned that the type of T helper cell response (Th1 or Th2) mounted by the host is critical to the outcome of infection, and we have identified key Th2- and Th1-associated cytokines that contribute to resistance or susceptibility, respectively. Notably, the number of these key cytokines is still growing. Our model of immunity to Trichuris has developed from one resolving round IL-4 and IFN-gamma to one that also has to accommodate IL-9, IL-10, IL-13, TNF-alpha, IL-12, and IL-18. Importantly, resistance to infection is not just about making an appropriate type 2 response. Effector cells have to be recruited locally to the site of infection in order to culminate in worm expulsion, which brings new key players into our model, including chemokines.

Quantitation of simian cytokine and beta-chemokine mRNAs, using real-time reverse transcriptase-polymerase chain reaction: variations in expression during chronic primate lentivirus infection

Cytokines and beta-chemokines are important mediators of the immune system and are expressed in many infectious diseases. To study cytokine and beta-chemokine profiles during pathogenesis of lentiviral infection and progression to AIDS in rhesus macaques, we established new quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assays based on TaqMan chemistry. Using synthetic RNA standards, we quantified mRNAs of IL-2, IL-4, IL-6, IL-10, IL-12 p40, interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), RANTES, macrophage inflammatory protein 1 alpha (MIP-1 alpha), and MIP-1 beta in unstimulated peripheral blood mononuclear cells (PBMCs) and lymph nodes from macaques chronically infected with SIV or SHIV. Viremic monkeys with decreased CD4(+) T cell counts (<500 cells/microl) had significantly higher IL-10 mRNA expression than uninfected controls, which parallels the findings in HIV-1-infected humans. In addition, MIP-1 alpha, MIP-1 beta, and RANTES mRNA expression increased in viremic monkeys with decreased CD4(+) T cell counts; gene expression was inversely correlated with CD4(+) T cell counts, but not viral load. The newly established quantitative real-time RT-PCR assays will allow the determination of cytokine and beta-chemokine patterns in rhesus macaques in studies of microbial pathogenesis or vaccine development.

Receptors involved in microenvironment-driven molecular evolution of cancer cells

Cells, including cancer cells, communicate with their microenvironment via various types of membrane receptors. An important down-stream effect of such interactions is a change in the molecular phenotype of the cells. The microenvironment-driven molecular evolution of cancer cells may induce either growth arrest or death of the cells or alternatively, boost their malignancy phenotype. In this paper we summarize studies from our own laboratory on interactions of cancer cells with microenvironmental ligands via two types of receptors that are not commonly associated with tumour progression i.e. the receptor for the Fc portion of IgG, and Ly-6 proteins of mouse and human origin. We also review information on interactions of tumour-associated chemokines and chemokine receptors with the corresponding microenvironmental factors. We demonstrate how these interactions may drive the molecular evolution of tumour cells and discuss the possible impact of this evolution on tumour progression.

Up-regulation of the chemokine receptor CCR7 in classical but not in lymphocyte-predominant Hodgkin disease correlates with distinct dissemination of neoplastic cells in lymphoid organs

Chemokines and chemokine receptors are key mediators for regulating cell traffic and positioning in both homeostatic and inflammatory conditions. It is also presumed that chemokines and their receptors are likely to play a critical role in the localization of malignant hematopoietic cells in their target organs. This study analyzed chemokine and chemokine receptor expression in several Hodgkin disease (HD)-derived cell lines and in HD tumors. All HD-derived cell lines expressed functional CCR7 and CXCR4 receptors. CCR7 up-regulation was mediated by constitutive NF-kappaB activity. Lymphoid tissues in HD revealed differential expression levels of CCR7, CXCR4, and CXCR5, depending on the distinct subtypes of HD. HD of the classical subtypes, predominantly located in the interfollicular zone, showed strong CCR7 and CXCR4 expression and moderate CXCR5 expression. In contrast, the nodular lymphocyte-predominant HD (NLP) subtype, regularly associated with follicular structures, exhibited no CCR7 reactivity but abundant CXCR4 staining. Their respective chemokine ligands showed marked expression by reactive cells within the tumors of classical HD and outside of the tumor nodules in NLPHD. Functionally, such differential chemokine receptor expression might contribute to specific localization and confinement of neoplastic cells within the target organs in the distinct HD entities.

The macrophage inflammatory protein-1beta in the supernatants of Mycoplasma gallisepticum-infected chicken leukocytes attracts the migration of chicken heterophils and lymphocytes

Chicken monocytes, macrophages, heterophils and thrombocytes were infected with Mycoplasma gallisepticum, and their supernatants were collected and tested for the presence of chemotactic activities. The supernatants from MG-infected monocytes and macrophages were able to attract the migration of both heterophils and lymphocytes. The chemotactic activity in these supernatants could be abolished by antibodies prepared against the 10 amino acid peptides of the macrophage inflammatory protein (MIP)-1beta, indicating that the released chemoattractant was a MIP-1beta-like compound. The supernatant from MG-infected heterophils was also able to attract the migration of chicken lymphocytes, but its activity could not be neutralized by the antibody to MIP-1beta, indicating that the chemoattractant is not related to MIP-1beta. The supernatants from both control and MG-infected thrombocytes were able to attract the migration of lymphocytes. These results indicate that there is more than one chemotactic factor that is released by these cells; one of the chemoattractants has been identified as a MIP-1beta. These results also show that MIP-1beta may play a role in the recruitment and accumulation of heterophils and lymphocytes to the sites of mycoplasma infection.

Potential role of the chemokine receptors CXCR3, CCR4, and the integrin alphaEbeta7 in the pathogenesis of psoriasis vulgaris

Various adhesion molecules have been implicated in T lymphocyte binding to dermal vascular endothelium in psoriasis vulgaris, but the chemotactic signals that promote subsequent homing into the adjacent dermis and overlying epidermis are poorly defined. We studied chemokine receptor (CCR1-CCR5, CXCR1-CXCR3), chemokine (interferon-gamma inducible protein 10 [IP-10]), monokine induced by interferon-gamma (MIG), thymus and activation-regulated chemokine (TARC), macrophage-derived chemokine (MDC), and adhesion molecule (cutaneous lymphocyte antigen [CLA], E-selectin, lymphocyte function-associated antigen-1 [LFA-1], intercellular adhesion molecule-1 [ICAM-1], very late antigen 4 [VLA-4], vascular cell adhesion molecule-1 [VCAM-1], alphaEbeta7, and E-cadherin) expression in psoriasis by immunohistology, flow cytometry, and molecular techniques. CXCR3 and CCR4 were expressed by dermal CD3+ lymphocytes, and their chemokine ligands, IP-10, MIG, TARC, and MDC, were up-regulated in psoriatic lesions. Keratinocytes stimulated with tumor necrosis factor-alpha and interferon-gamma up-regulated expression of IP-10, MIG, and MDC mRNA, whereas dermal endothelial cells, similarly stimulated, up-regulated expression of IP-10, MDC, and TARC mRNA, suggesting that these cell types were sources of the chemokines detected in biopsies. There was enhanced expression of E-selectin, CLA, LFA-1, ICAM-1, VLA-4, VCAM-1, and alphaEbeta7 in psoriatic lesions versus nonlesional skin. Finally, intra-epidermal CLA+ and alphaEbeta7+ T lymphocytes selectively expressed the chemokine receptor CXCR3. Collectively, these data suggest that CXCR3 and CCR4 may be involved in T lymphocyte trafficking to the psoriatic dermis and that CXCR3 is selectively involved in subsequent T cell homing to the overlying epidermis.