Identification of CRG-2. An interferon-inducible mRNA predicted to encode a murine monokine

Differential Anti-Tumor Effects of IFN-Inducible Chemokines CXCL9, CXCL10, and CXCL11 on a Mouse Squamous Cell Carcinoma Cell Line

Chemokines are a group of cytokines involved in the mobilization of leukocytes, which play a role in host defense and a variety of pathological conditions, including cancer. Interferon (IFN)-inducible chemokines C-X-C motif ligand 9 (CXCL), CXCL10, and CXCL11 are anti-tumor chemokines; however, the differential anti-tumor effects of IFN-inducible chemokines are not completely understood. In this study, we investigated the anti-tumor effects of IFN-inducible chemokines by transferring chemokine expression vectors into a mouse squamous cell carcinoma cell line, SCCVII, to generate a cell line stably expressing chemokines and transplanted it into nude mice. The results showed that CXCL9- and CXCL11-expressing cells markedly inhibited tumor growth, whereas CXCL10-expressing cells did not inhibit growth. The NH₂-terminal amino acid sequence of mouse CXCL10 contains a cleavage sequence by dipeptidyl peptidase 4 (DPP4), an enzyme that cleaves the peptide chain of chemokines. IHC staining indicated DPP4 expression in the stromal tissue, suggesting CXCL10 inactivation. These results suggest that the anti-tumor effects of IFN-inducible chemokines are affected by the expression of chemokine-cleaving enzymes in tumor tissues.

Dynamics of Type I and Type II Interferon Signature Determines Responsiveness to Anti-TNF Therapy in Rheumatoid Arthritis

The factors influencing long-term responses to a tumor necrosis factor inhibitor (TNFi) in rheumatoid arthritis (RA) patients currently remain unknown. Therefore, we herein conducted a multi-omics analysis of TNFi responses in a Japanese RA cohort. Blood samples were collected from 27 biological disease-modifying antirheumatic drug (DMARD)-naive RA patients at the initiation of and after three months of treatment with TNFi. Treatment responses were evaluated at one year. Differences in gene expression levels in peripheral blood mononuclear cells (PBMCs), plasma protein levels, drug concentrations, and the presence/absence of anti-drug antibodies were investigated, and a cell phenotypic analysis of PBMCs was performed using flow cytometry. After one year of treatment, thirteen patients achieved clinical remission (responders), while the others did not or switched to other biologics (non-responders). Differentially expressed genes related to treatment responses were enriched for the interferon (IFN) pathway. The expression of type I IFN signaling-related genes was higher in non-responders than in responders before and after treatment (P = 0.03, 0.005, respectively). The expression of type II IFN signaling-related genes did not significantly differ before treatment; however, it increased in non-responders and decreased in responders, with a significant difference being observed after three months of treatment (P = 1.2×10^-3). The total number of lymphocytes and C-X-C Motif Chemokine Ligand 10 (CXCL10) protein levels were associated with the type I IFN signature (P = 6.7×10^-7, 6.4×10^-3, respectively). Hepatocyte growth factor (HGF) protein levels before treatment predicted fold increases in type II IFN (P = 0.03). These IFN signature-related indices (the number of lymphocytes, CXCL10, and HGF) significantly differed between responders and non-responders (P = 0.01, 0.01, and 0.04, respectively). A single-cell analysis revealed that the type I IFN signature was more highly enriched in monocytes than in other cell types. A deconvolution analysis of bulk-RNA sequence data identified CD4+ and CD8+ T cells as the main sources of the type II IFN signature in non-responders. Collectively, the present results demonstrated that the dynamics of the type I and II IFN pathways affected long-term responses to TNFi, providing information on its biological background and potential for clinical applications.

Cytokines, chemokines and growth factors profile in human aqueous humor in idiopathic uveitis

To investigate which cytokines, chemokines and growth factors are involved in the immunopathogenesis of idiopathic uveitis, and whether cytokine profiles are associated with. Serum and aqueous humor (AH) samples of 75 patients with idiopathic uveitis were analyzed by multiplex immunoassay. Infectious controls consisted of 16 patients with ocular toxoplasmosis all confirmed by intraocular fluid analyses. Noninfectious controls consisted of 7 patients with Behçet disease related uveitis and 15 patients with sarcoidosis related uveitis. The control group consisted of AH and serum samples from 47 noninflammatory control patients with age-related cataract. In each sample, 27 immune mediators ± IL-21 and IL-23 were measured. In idiopathic uveitis, 13 of the 29 mediators, including most proinflammatory and vascular mediators such as IL-6, IL-8, IL-12, G-CSF, GM-CSF, MCP-1, IP-10, TNF-α and VEGF, were significantly elevated in the aqueous humor when compared to all controls. Moreover, IL-17, IP-10, and IL-21, were significantly elevated in the serum when compared to all controls. We clustered 4 subgroups of idiopathic uveitis using a statistical analysis of hierarchical unsupervised classification, characterized by the order of magnitude of concentrations of intraocular cytokines. The pathogenesis of idiopathic uveitis is characterized by the presence of predominantly proinflammatory cytokines and chemokines and vascular endothelial growth factor with high expression levels as compared to other causes of uveitis. There are indications for obvious Th-1/ IL21-Th17 pathways but also IL9-Th9 and increased IFN-γ-inducing cytokine (IL12) and IFN-γ-inducible CXC chemokine (IP-10). The combined data suggest that immune mediator expression is different among idiopathic uveitis. This study suggests various clusters among the idiopathic uveitis group rather than one specific uveitis entity.

Plasmacytoid dendritic cells as a possible key player to initiate alopecia areata in the C3H/HeJ mouse

BACKGROUND

Alopecia areata (AA) is a tissue-specific autoimmune disease, and interferon (IFN)-γ has been regarded as the key cytokine in the pathogenesis of AA. The clinical observation that AA can occur after viral infection or IFN-α administration implies that IFN-α-producing plasmacytoid dendritic cells (pDCs) may be involved in the AA pathogenesis.

METHODS

We generated AA in C3H/HeJ mice by intradermal injection of T cells derived from lymph nodes of AA-bearing syngeneic mice and stimulated IL-2, IL-7, and IL-15. Distribution of IFN-γ producing pDCs were immunohistochemically analyzed. Realtime PCR were also demonstrated to detect the expression of IFN-γ mRNA. Hair follicles were cultured with IFN-α in order to calculate the hair elongation. Imiquimod was employed to induce catagen stage. PDCs were injected into C3H/HeJ mice to initiate AA.

RESULTS

In this mouse, IFN-α-producing pDCs densely infiltrated around HFs in not only AA lesional but also vicinity of AA lesion. Importantly, intradermal injection of pDCs induced AA lesions. Finally, IFN-α inhibited hair elongation of murine vibrissae and upregulated MHC class I and CXCL10 levels in vitro.

CONCLUSIONS

These findings suggest that IFN-α-producing pDCs initiate AA by inducing apoptosis and increasing Th1/Tc1 chemokine production such as CXCL10, that accumulates Th1/Tc1 cells and result in autoimmune reactions against hair follicles.

Key features and homing properties of NK cells in the liver are shaped by activated iNKT cells

The contribution of natural killer (NK) cells to the clearance of hepatic viral infections is well recognized. The recently discovered heterogeneity of NK cell populations renders them interesting targets for immune interventions. Invariant natural killer T (iNKT) cells represent a key interaction partner for hepatic NK cells. The present study addressed whether characteristics of NK cells in the liver can be shaped by targeting iNKT cells. For this, the CD1d-binding pegylated glycolipid αGalCerMPEG was assessed for its ability to modulate the features of NK cells permanently or transiently residing in the liver. In vivo administration resulted in enhanced functionality of educated and highly differentiated CD27⁺ Mac-1⁺ NK cells accompanied by an increased proliferation. Improved liver homing was supported by serum-derived and cellular factors. Reduced viral loads in a mCMV infection model confirmed the beneficial effect of NK cells located in the liver upon stimulation with αGalCerMPEG. Thus, targeting iNKT cell-mediated NK cell activation in the liver represents a promising approach for the establishment of liver-directed immune interventions.

Expression of a constitutively active human STING mutant in hematopoietic cells produces an Ifnar1-dependent vasculopathy in mice

Transgenic expression of a mutant hSTING cDNA under the control of the Vav1 gene promoter leads to a vasculopathy similar to that of the interferonopathy, STING-associated vasculopathy of infancy.

STING-associated vasculopathy with onset in infancy (SAVI) is an autoinflammatory disorder characterized by blood vessel occlusions, acral necrosis, myositis, rashes, and pulmonary inflammation that are the result of activating mutations in the STimulator of Interferon Genes (STING). We generated a transgenic line that recapitulates many of the phenotypic aspects of SAVI by targeting the expression of the human STING-N154S–mutant protein to the murine hematopoietic compartment. hSTING-N154S mice demonstrated failure to gain weight, lymphopenia, progressive paw swelling accompanied by inflammatory infiltrates, severe myositis, and ear and tail necrosis. However, no significant lung inflammation was observed. X-ray microscopy imaging revealed vasculopathy characterized by arteriole occlusions and venous thromboses. Type I interferons and proinflammatory mediators were elevated in hSTING-N154S sera. Importantly, the phenotype was prevented in hSTING-N154S mice lacking the type I interferon receptor gene (Ifnar1). This model, based on a mutant human STING protein, may shed light on the pathophysiological mechanisms operative in SAVI.

Innate Immune Responses and Viral-Induced Neurologic Disease

Multiple sclerosis (MS) is a disease of the central nervous system (CNS) characterized by chronic neuroinflammation, axonal damage, and demyelination. Cellular components of the adaptive immune response are viewed as important in initiating formation of demyelinating lesions in MS patients. This notion is supported by preclinical animal models, genome-wide association studies (GWAS), as well as approved disease modifying therapies (DMTs) that suppress clinical relapse and are designed to impede infiltration of activated lymphocytes into the CNS. Nonetheless, emerging evidence demonstrates that the innate immune response e.g., neutrophils can amplify white matter damage through a variety of different mechanisms. Indeed, using a model of coronavirus-induced neurologic disease, we have demonstrated that sustained neutrophil infiltration into the CNS of infected animals correlates with increased demyelination. This brief review highlights recent evidence arguing that targeting the innate immune response may offer new therapeutic avenues for treatment of demyelinating disease including MS.

Chemokine CXCL10 and Coronavirus-Induced Neurologic Disease

Chemokines (chemotactic cytokines) are involved in a wide variety of biological processes. Following microbial infection, there is often robust chemokine signaling elicited from infected cells, which contributes to both innate and adaptive immune responses that control growth of the invading pathogen. Infection of the central nervous system (CNS) by the neuroadapted John Howard Mueller (JHM) strain of mouse hepatitis virus (JHMV) provides an excellent example of how chemokines aid in host defense as well as contribute to disease. Intracranial inoculation of the CNS of susceptible mice with JHMV results in an acute encephalomyelitis characterized by widespread dissemination of virus throughout the parenchyma. Virus-specific T cells are recruited to the CNS, and control viral replication through release of antiviral cytokines and cytolytic activity. Sterile immunity is not acquired, and virus will persist primarily in white matter tracts leading to chronic neuroinflammation and demyelination. Chemokines are expressed and contribute to defense as well as chronic disease by attracting targeted populations of leukocytes to the CNS. The T cell chemoattractant chemokine CXCL10 (interferon-inducible protein 10 kDa, IP-10) is prominently expressed in both stages of disease, and serves to attract activated T and B lymphocytes expressing CXC chemokine receptor 3 (CXCR3), the receptor for CXCL10. Functional studies that have blocked expression of either CXCL10 or CXCR3 illuminate the important role of this signaling pathway in host defense and neurodegeneration in a model of viral-induced neurologic disease.

Structure and Composition Define Immunorecognition of Nucleic Acid Nanoparticles

Nucleic acid nanoparticles (NANPs) have evolved as a new class of therapeutics with the potential to detect and treat diseases. Despite tremendous advancements in NANP development, their immunotoxicity, one of the major impediments in clinical translation of traditional therapeutic nucleic acids (TNAs), has never been fully characterized. Here, we describe the first systematically studied immunological recognition of 25 representative RNA and DNA NANPs selected to have different design principles and physicochemical properties. We discover that, unlike traditional TNAs, NANPs used without a delivery carrier are immunoquiescent. We show that interferons (IFNs) are the key cytokines triggered by NANPs after their internalization by phagocytic cells, which agrees with predictions based on the experiences with TNAs. However, in addition to type I IFNs, type III IFNs also serve as reliable biomarkers of NANPs, which is usually not characteristic of TNAs. We show that overall immunostimulation relies on NANP shapes, connectivities, and compositions. We demonstrate that, like with traditional TNAs, plasmacytoid dendritic cells serve as the primary interferon producers among all peripheral blood mononuclear cells treated with NANPs, and scavenger receptor-mediated uptake and endosomal Toll-like receptor signaling are essential for NANP immunorecognition. The TLR involvement, however, is different from that expected for traditional TNA recognition. Based on these results, we suggest that NANP technology may serve as a prototype of auxiliary molecular language for communication with the immune system and the modulation of immune responses.

Obese donor mice splenocytes aggravated the pathogenesis of acute graft-versus-host disease via regulating differentiation of Tregs and CD4+ T cell induced-type I inflammation

Acute graft-versus-host disease (aGVHD) remains one of the most severe complications in organ and bone marrow transplantation, leading to much morbidity and mortality. Obesity has been associated with increased risk of development of various inflammatory diseases. Here, we investigated the in vitro and in vivo effects of obese donor splenocytes on the development of acute graft-versus-host disease (aGVHD). In this study, mixed lymphocyte reactions (MLR) in vitro showed that obese donor mouse CD4+ T cell promoted the production of interleukin-2 (IL-2), interferon (IFN)-γ and tumor necrosis factor (TNF)-α. Meanwhile, the inducible Tregs population decreased greatly in obese donor mouse CD4+ T cells' induction group, compared with normal group. Then in the murine aGVHD model, we found that obese donor splenocytes dramatically increased the severity of aGVHD through down-regulating immune tolerance while enhancing systemic and local immunity. Moreover, we showed that aGVHD induced by obese donors resulted in massive expansion of donor CD3+ T cells, release of Th1-related cytokines, interleukin-17 (IL-17) and chemokines, significant increase of Th17 cells and inhibition of CD4+CD25+Foxp3+ regulatory T cells (Tregs) and impaired suppressive ability of donor Tregs. Expression of sphingosine-1-phosphate receptor 1 (S1PR1), phosphorylated Akt, mammalian target of rapamycin (mTOR) and Raptor increased, while the phosphorylation level of SMAD3 was decreased in the skin, intestine, lung and liver from obese donor splenocytes-treated aGVHD mice. Furthermore, at mRNA and protein levels, we defined several molecules that may account for the enhanced ability of obese donor splenocytes to migrate into target organs, such as IL-2, IL-17, IFN-γ, TNF-α, CXCR3, CXCL9, CXCL10, CXCL11 and CCL3. Therefore, these results imply that obese donor cells may be related to the risk of aGVHD and helping obese donor individuals lose weight represent a compulsory clinical strategy before implementing transplantation to control aGVHD of recipients.

The chemokine CXCL9 exacerbates chemotherapy-induced acute intestinal damage through inhibition of mucosal restitution

PURPOSE

Acute intestinal damage induced by chemotherapeutic agent is often a dose-limiting factor in clinical cancer therapy. The aim of this study was to investigate the effect of chemokine CXCL9 on the intestinal damage after chemotherapy and explore the therapeutic potential of anti-CXCL9 agents.

METHODS

In vitro cell proliferation assay was performed with a non-tumorigenic human epithelial cell line MCF10A. Multiple pathway analysis was carried out to explore the pathway that mediated the effect of CXCL9, and the corresponding downstream effector was identified with enzyme-linked immunosorbent assays. Chemotherapy-induced mouse model of intestinal mucositis was prepared by a single injection of the chemotherapeutic agent 5-fluorouracil (5-FU). In vivo expression of cxcl9 and its receptor cxcr3 in intestinal mucosa after chemotherapy was determined by quantitative real-time PCR. Therapeutic treatment with anti-CXCL9 antibodies was investigated to confirm the hypothesis that CXCL9 can contribute to the intestinal epithelium damage induced by chemotherapy.

RESULTS

CXCL9 inhibited the proliferation of MCF10A cells by activating phosphorylation of p70 ribosomal S6 kinase (p70S6K), which further promotes the secretion of transforming growth factor beta (TGF-β) as the downstream effector. A blockade of phospho-p70S6K with inhibitor abolished the effect of CXCL9 on MCF10A cells and reduced the secretion of TGF-β. The expression levels of cxcl9 and cxcr3 were significantly up-regulated in intestinal mucosa after 5-FU injection. Neutralizing elevated CXCL9 with anti-CXCR9 antibodies successfully enhanced reconstitution of intestinal mucosa and improved the survival rate of mice that received high-dose chemotherapy.

CONCLUSIONS

CXCL9 inhibits the proliferation of epithelial cells via phosphorylation of p70S6K, resulting in the excretion of TGF-β as downstream mediator. CXCL9/CXCR3 interaction can exacerbate chemotherapeutic agent-induced intestinal damage, and anti-CXCL9 agents are potential novel therapeutic candidates for promoting mucosal restitution.

Overproduction of CXC chemokines CXCL1, CXCL9, CXCL10 and CXCL12 in β-thalassemia major or patients

BACKGROUNDS AND OBJECTIVES

B-thalassemia major is one of the most frequent hematological genetic disorders, worldwide. Chemokines are the main components of the immune system and play fundamental roles in pathogenesis of inflammatory disorders. Therefore, the present study aimed to examine whether serum CXC chemokines are altered in b-thalassemia major patients.

DESIGN AND SETTINGS

We enrolled 63 b-thalassemia patients and 80 controls in this cross-sectional study, which was performed during 2012-2013 in Kerman, Iran.

METHODS

We enrolled 63 b-thalassemia patients and 80 controls in the present study. Patients were selected from referrals to Samenolhojaj clinic for thalassemia, Kerman, Iran. The circulating levels of CXCL1, CXCL9, CXCL10, and CXCL12 were detected by enzyme-linked immunosorbent assay in thalassemia patients and healthy controls immediately after blood collection. Data were analyzed by c2, t-test, and analysis of variance statistical methods and using SPSS, version 13 (SPSS Inc., Chicago, IL).

RESULTS

The results of the study demonstrated a significant elevation of CXCL1, CXCL9, CXCL10, and CXCL12 in thalassemia patients than in control. These results also demonstrated that serum chemokine levels are related to transfusion duration and post-transfusion viral infections.

CONCLUSION

According to the results obtained, it can probably be concluded that chemokines are also involved in the pathogenesis of b-thalassemia major and its clinical complications in addition to several other parameters.

Divergent effects of T cell costimulation and inflammatory cytokine production on autoimmune peripheral neuropathy provoked by Aire deficiency

Chronic inflammatory demyelinating polyneuropathy results from autoimmune destruction of the peripheral nervous system and is a component of the multiorgan autoimmunity syndrome that results from Aire gene mutations in humans. In parallel, peripheral nervous system autoimmunity resembling chronic inflammatory demyelinating polyneuropathy develops spontaneously in NOD mice with a partial loss of Aire function (NOD.Aire(GW/+) mice) and is a T cell-mediated disease. In this study, we analyze how key aspects of T cell activation and function modulate disease development in Aire-deficient mice. We show that genetic ablation of the Th1 cytokine IFN-γ completely prevents clinical and electrophysiological evidence of neuropathy in NOD.Aire(GW/+) mice. IFN-γ deficiency is associated with absence of immune infiltration and decreased expression of the T cell chemoattractant IP-10 in sciatic nerves. Thus, IFN-γ is absolutely required for the development of autoimmune peripheral neuropathy in NOD.Aire(GW/+) mice. Because IFN-γ secretion is enhanced by B7-CD28 costimulation of T cells, we sought to determine the effects of these costimulatory molecules on neuropathy development. Surprisingly, B7-2 deficiency accelerated neuropathy development in NOD.Aire(GW/+) mice, and Ab blockade of both B7-1 and B7-2 resulted in fulminant, early-onset neuropathy. Thus, in contrast to IFN-γ, B7-2 alone and B7-1/B7-2 in combination function to ameliorate neuropathy development in NOD.Aire(GW/+) mice. Together, these findings reveal distinct and opposing effects of the T cell costimulatory pathway and IFN-γ production on the pathogenesis of autoimmune peripheral neuropathy.

Enterovirus 71 infection increases expression of interferon-gamma-inducible protein 10 which protects mice by reducing viral burden in multiple tissues

Enterovirus 71 (EV71) infection has induced fatal encephalitis in thousands of young children in the Asia-Pacific region over the last decade. EV71 infection continues to cause serious problems in areas with outbreaks, because vaccines and antiviral therapies are not available. Lymphocytes are present in the brains of infected patients and mice, and they protect mice from infection by decreasing the viral burden. The chemokines responsible for recruiting lymphocytes to infected organs are yet to be identified. Among the lymphocyte chemokines detected, high levels of interferon-gamma-inducible protein-10 (IP-10) are found in the plasma and cerebral spinal fluid of patients with brainstem encephalitis as compared with the levels of a monokine induced by gamma interferon (Mig). Using a murine model to investigate the induction of IP-10 by EV71 infection, we observed that EV71 infection significantly enhanced IP-10 protein expression in the serum and brain, with kinetics similar to viral titres in the blood and brain. Brain neurons of infected mice expressed IP-10. Using wild-type mice and IP-10 gene knockout mice to investigate the role of IP-10 in EV71 infection, we found that IP-10 deficiency significantly reduced levels of Mig in serum, and levels of gamma interferon and the number of CD8 T cells in the mouse brain. Absence of IP-10 significantly increased the mortality of infected mice by 45%, with slow virus clearance in several vital tissues. Our observations are consistent with a model where EV71 infection boosts IP-10 expression to increase gamma interferon and Mig levels, infiltration of CD8 T cells, virus clearance in tissues and the survival of mice.

Suppression of IP-10/CXCL10 gene expression in LPS- and/or IFN-γ-stimulated macrophages by parasite-secreted products

T helper (Th)2 polarized immune responses are characteristically dominant in helminth infections. The gene expression of interferon (IFN)-γ-inducible protein 10 (IP-10/CXCL10), which promotes Th1 responses, in mouse macrophages stimulated with lipopolysaccharide (LPS) and/or IFN-γ was suppressed by excretory/secretory (ES) products of Spirometra erinaceieuropaei plerocercoids. ES products suppressed LPS- and/or IFN-γ-induced transcriptional activities of a luciferase reporter gene under the control of a 243-bp fragment of the IP-10 gene promoter/enhancer, which contains an IFN-stimulated response element (ISRE) and two κB elements. Consistent with this result, ES products inhibited ISRE-dependent heterologous promoter activities and LPS- or IFN-γ-induced ISRE-binding activity. ES products also suppressed LPS-induced IFN-β gene expression. Furthermore, ES products suppressed nuclear factor (NF)-κB RelA (p65)-dependent transcriptional activity, whereas ES products had no effect on the κB-binding activity. These results suggest that ES products suppress the IP-10 gene expression by inhibiting the ISRE- and RelA-dependent transcriptional activities in mouse macrophages.

Immune markers in breast milk and fetal and maternal body fluids: a systematic review of perinatal concentrations

Breastfeeding represents the continued exposure of the infant to the maternal immune environment.Uterine, perinatal, and postnatal exposure to immune factors may contribute to an infant’s risk of developing immune-mediated disorders, including allergies. A PubMed search was conducted to review studies in humans and analyze concentrations of immune markers (TGF-beta, IFN-gamma, eotaxin, CCL5, CXCL10, TNF-alpha, MCP-1, IL-1beta, IL-4, IL-5, IL-6,IL-8, IL-10, IL-12, IL-13, sCD14, sIgA, IgG4, IgM) found in maternal serum, amniotic fluid, cord serum, colostrum, transition and mature milk. Concentrations of immune markers showed large variations across samples and studies. Reports documented conflicting results. Small sample sizes, differences in population characteristics, inconsistent sample collection times, and various sample collection and measurement methods may have led to wide variations in the concentrations of immune markers. Studies analyzing the associations between immune markers in maternal fluids and infant allergies remain inconclusive because of gaps in knowledge and a lack of standardized methods.

Expression of chemokine receptor CXCR3 on T cells affects the balance between effector and memory CD8 T-cell generation

Generation of a robust immunological memory response is essential for protection on subsequent encounters with the same pathogen. The magnitude and quality of the memory CD8 T-cell population are shaped and influenced by the strength and duration of the initial antigenic stimulus as well as by inflammatory cytokines. Although chemokine receptors have been established to play a role in recruitment of effector CD8 T cells to sites of inflammation, their contribution to determination of T-cell fate and shaping of the long-lived memory T-cell population is not fully understood. Here, we investigated whether reduced access to antigen and inflammation through alterations in expression of inflammatory and homeostatic chemokine receptors has an impact on generation of effector and memory CD8 T cells. We found that in mice infected with lymphocytic choriomeningitis virus, colocalization of virus-specific CD8 T cells with antigen in spleen is dependent on expression of the inflammatory chemokine receptor, CXCR3. In addition, absence of CXCR3 expression on CD8 T cells leads to formation of fewer short-lived effector cells and more memory precursor cells. Furthermore, the memory CD8 T-cell population derived from CXCR3-deficient cells has fewer cells of the effector memory phenotype and exhibits a recall response of greater magnitude than that of WT cells. These data demonstrate that CD8 T-cell positioning relative to antigen and inflammatory cytokines in secondary lymphoid organs affects the balance of effector and memory T-cell formation and has both a quantitative and qualitative impact on the long-lived memory CD8 T-cell population.

The cell-specific induction of CXC chemokine ligand 9 mediated by IFN-gamma in microglia of the central nervous system is determined by the myeloid transcription factor PU.1

The IFN-gamma-inducible chemokines CXCL9 and CXCL10 are implicated in the pathogenesis of T cell-mediated immunity in the CNS. However, in various CNS immune pathologies the cellular localization of these chemokines differs, with CXCL9 produced by macrophage/microglia whereas CXCL10 is produced by both macrophage/microglia and astrocytes. In this study, we determined the mechanism for the microglial cell-restricted expression of the Cxcl9 gene induced by IFN-gamma. In cultured glial cells, the induction of the CXCL9 (in microglia) and CXCL10 (in microglia and astrocytes) mRNAs by IFN-gamma was not inhibited by cycloheximide. Of various transcription factors involved with IFN-gamma-mediated gene regulation, PU.1 was identified as a constitutively expressed NF in microglia but not in astrocytes. STAT1 and PU.1 bound constitutively to the Cxcl9 gene promoter in microglia, and this increased significantly following IFN-gamma treatment with IFN regulatory factor-8 identified as an additional late binding factor. However, in astrocytes, STAT1 alone bound to the Cxcl9 gene promoter. STAT1 was critical for IFN-gamma induction of both the Cxcl9 and Cxcl10 genes in microglia and in microglia and astrocytes, respectively. The small interfering RNA-mediated knockdown of PU.1 in microglia markedly impaired IFN-gamma-induced CXCL9 but not STAT1 or IFN regulatory factor-8. Cells of the D1A astrocyte line showed partial reprogramming to a myeloid-like phenotype posttransduction with PU.1 and, in addition to the expression of CD11b, acquired the ability to produce CXCL9 in response to IFN-gamma. Thus, PU.1 not only is crucial for the induction of CXCL9 by IFN-gamma in microglia but also is a key determinant factor for the cell-specific expression of this chemokine by these myeloid cells.

Peli1 facilitates TRIF-dependent Toll-like receptor signaling and proinflammatory cytokine production

Toll-like receptors (TLRs) are pivotal in innate immunity and inflammation. Here we show that genetic deficiency in Peli1, an E3 ubiquitin ligase, attenuated the induction of proinflammatory cytokines by ligands of TLR3 and TLR4 and rendered mice resistant to septic shock. Peli1 was required for TLR3-induced activation of IkappaB kinase (IKK) and its 'downstream' target, transcription factor NF-kappaB, but was dispensable for IKK-NF-kappaB activation induced by several other TLRs and the interleukin 1 (IL-1) receptor. Notably, Peli1 bound to and ubiquitinated RIP1, a signaling molecule that mediates IKK activation induced by the TLR3 and TLR4 adaptor TRIF. Our findings suggest that Peli1 is a ubiquitin ligase needed for the transmission of TRIF-dependent TLR signals.

Elucidating the molecular physiopathology of acute respiratory distress syndrome in severe acute respiratory syndrome patients

Acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury. It is a response to various diseases of variable etiology, including SARS-CoV infection. To date, a comprehensive study of the genomic physiopathology of ARDS (and SARS) is lacking, primarily due to the difficulty of finding suitable materials to study the disease process at a tissue level (instead of blood, sputa or swaps). Hereby we attempt to provide such study by analyzing autopsy lung samples from patient who died of SARS and showed different degrees of severity of the pulmonary involvement. We performed real-time quantitative PCR analysis of 107 genes with functional roles in inflammation, coagulation, fibrosis and apoptosis; some key genes were confirmed at a protein expression level by immunohistochemistry and correlated to the degree of morphological severity present in the individual samples analyzed. Significant expression levels were identified for ANPEP (a receptor for CoV), as well as inhibition of the STAT1 pathway, IFNs production and CXCL10 (a T-cell recruiter). Other genes unassociated to date with ARDS/SARS include C1Qb, C5R1, CASP3, CASP9, CD14, CD68, FGF7, HLA-DRA, IGF1, IRF3, MALAT-1, MSR1, NFIL3, SLPI, USP33, CLC, GBP1 and TAC1. As a result, we proposed to therapeutically target some of these genes with compounds such as ANPEP inhibitors, SLPI and dexamethasone. Ultimately, this study may serve as a model for future, tissue-based analyses of fibroinflammatory conditions affecting the lung.

Essential involvement of cross-talk between IFN-gamma and TNF-alpha in CXCL10 production in human THP-1 monocytes

Interferon (IFN)-gamma-induced protein 10 (IP-10/CXCL10), a CXC chemokine, has been documented in several inflammatory and autoimmune disorders including atopic dermatitis and bronchial asthma. Although CXCL10 could be induced by IFN-gamma depending on cell type, the mechanisms regulating CXCL10 production following treatment with combination of IFN-gamma and TNF-alpha have not been adequately elucidated in human monocytes. In this study, we showed that TNF-alpha had more potential than IFN-gamma to induce CXCL10 production in THP-1 monocytes. Furthermore, IFN-gamma synergistically enhanced the production of CXCL10 in parallel with the activation of NF-kappaB in TNF-alpha-stimulated THP-1 cells. Blockage of STAT1 or NF-kappaB suppressed CXCL10 production. JAKs inhibitors suppressed IFN-gamma plus TNF-alpha-induced production of CXCL10 in parallel with activation of STAT1 and NF-kappaB, while ERK inhibitor suppressed production of CXCL10 as well as activation of NF-kappaB, but not that of STAT1. IFN-gamma-induced phosphorylation of JAK1 and JAK2, whereas TNF-alpha induced phosphorylation of ERK1/2. Interestingly, IFN-gamma alone had no effect on phosphorylation and degradation of IkappaB-alpha, whereas it significantly promoted TNF-alpha-induced phosphorylation and degradation of IkappaB-alpha. These results suggest that TNF-alpha induces CXCL10 production by activating NF-kappaB through ERK and that IFN-gamma induces CXCL10 production by increasing the activation of STAT1 through JAKs pathways. Of note, TNF-alpha-induced NF-kappaB may be the primary pathway contributing to CXCL10 production in THP-1 cells. IFN-gamma potentiates TNF-alpha-induced CXCL10 production in THP-1 cells by increasing the activation of STAT1 and NF-kappaB through JAK1 and JAK2.

Antitumor efficacy of combination of interferon-gamma-inducible protein 10 gene with gemcitabine, a study in murine model

Background

Interferon-γ-inducible protein 10 (IP-10) is a potent inhibitor of tumor angiogenesis. It has been reported that the antiangiogenic therapy combined with chemotherapy has synergistic effects.

Methods

To elucidate the mechanisms of IP-10 gene combined with a chemotherapy agent, we intramuscularly injected pBLAST-IP-10 expression plasmid combined with gemcitabine into tumor-bearing mice.

Results

The proliferation of endothelial cells was effectively inhibited by IP-10 combined with gemcitabine in vitro. Treatment with pBLAST-IP-10 twice a week for 4 weeks combined with gemcitabine 10 mg/kg (once a week) resulted in sustained high level of IP-10 protein in serum, inhibition of tumor growth and prolongation of the survival of tumor-bearing mice. Compared with administration of IP-10 plasmid or gemcitabine alone, the angiogenesis in tumors were apparently inhibited, and the numbers of apoptotic cells and lymphocytes in tumor increased in the combination therapy group.

Conclusion

Our data indicate that the gene therapy of antiangiogenesis by intramuscular delivery of plasmid DNA encoding IP-10 combined with gemcitabine has synergistic effects on tomor by inhibiting the proliferation of endothelail cells, inducing the apoptosis of tumor cells, and recruiting lymphocytes to tumor in murine models. The present findings provided evidence of antitumor effects of genetherapy combined with chemotherapy.

Intratumoral injection of inactivated Sendai virus particles elicits strong antitumor activity by enhancing local CXCL10 expression and systemic NK cell activation

We have already demonstrated that inactivated, replication-defective Sendai virus particles (HVJ-E) have a powerful antitumor effect by both the generation of tumor-specific cytotoxic T cells and inhibition of regulatory T cell activity. Here, we report that HVJ-E also has an antitumor effect through non-T cell immunity. Microarray analysis revealed that direct injection of HVJ-E induced the expression of CXCL10 in established Renca tumors. CXCL10 was secreted by dendritic cells in the tumors after HVJ-E injection. Quantitative real-time RT-PCR and immunohistochemistry revealed that CXCR3+ cells (predominantly NK cells) infiltrated the HVJ-E-injected tumors. Moreover, HVJ-E injection caused systemic activation of NK cells and enhanced their cytotoxity against tumor cells. In an in vivo experiment, approximately 50% of tumors were eradicated by HVJ-E injection, and this activity of HVJ-E against Renca tumors was largely abolished by NK cell depletion using anti-asialo GM1 antibody. Since HVJ-E injection induced systemic antitumor immunity by enhancing or correcting the chemokine-chemokine receptor axis, it might be a potential new therapy for cancer.

Induction of the genes for Cxcl9 and Cxcl10 is dependent on IFN-gamma but shows differential cellular expression in experimental autoimmune encephalomyelitis and by astrocytes and microglia in vitro

The chemokines CXCL9 and CXCL10 bind to the common receptor CXCR3 and are implicated in the pathogenesis of T-cell-mediated immunity in the central nervous system (CNS). Here we examined the temporal and spatial regulation of the Cxcl9 and Cxcl10 genes in the CNS of mice with myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) and by glial cells in vitro. During peak disease the levels of CXCL9 and CXCL10 mRNA and protein were increased significantly in the cerebellum and spinal cord but were reduced during the recovery phase. Expression of these genes in the CNS was abolished in IFN-gamma-receptor deficient mice with MOG-EAE. In wild-type mice, CXCL9 RNA was localized mainly to infiltrating mononuclear cells including lesion and perilesional microglia, while CXCL10 RNA was seen primarily in more distal astrocytes that surrounded the inflammatory lesions. Examination of cultured glia following treatment with IFN-gamma revealed that while both CXCL9 and CXCL10 mRNA transcripts were induced in microglia, only CXCL10 mRNA was induced in astrocytes. Thus, although IFN-gamma is the pivotal mediator of both Cxcl10 and Cxcl9 gene expression in EAE, this cytokine differentially regulates the expression of these genes by astrocytes and microglia. The differential glial localization of these chemokines in EAE suggests CXCL9 and CXCL10 have specialized functions.

Brucella requires a functional Type IV secretion system to elicit innate immune responses in mice

The virB operon, encoding a Type IV secretion system (T4SS), is essential for intracellular survival and persistent infection by Brucella spp. To better understand the role of the T4SS in evading host defence mechanisms and establishing chronic infection, we compared transcriptional profiles of the host response to infection with wild-type and virB mutant Brucella strains. Analysis of gene expression profiles in murine splenocytes 3 days after inoculation with wild-type Brucella strains revealed an inflammatory response, with a prominent upregulation of genes induced by both type I and type II interferons. Real-time RT-PCR showed that a group of genes from these pathways were induced by day 3 post infection and declined to baseline levels by day 7. In contrast, neither of the two virB mutant strains elicited a proinflammatory gene expression profile, demonstrating that the T4SS was required to trigger this response. Infection studies using type I interferon receptor knockout mice showed that a lack of type I interferon signalling did not affect Brucella replication during the first 4 weeks of infection. Thus, induction of type I interferons does not appear to be an essential mechanism by which the T4SS promotes persistent infection by Brucella.

CXCR3-dependent recruitment of antigen-specific T lymphocytes to the liver during murine cytomegalovirus infection

Innate inflammatory events promoting antiviral defense in the liver against murine cytomegalovirus (MCMV) infection have been characterized. However, the mechanisms that regulate the selective recruitment of inflammatory T lymphocytes to the liver during MCMV infection have not been defined. The studies presented here demonstrate the expression of monokine induced by gamma interferon (IFN-gamma; Mig/CXCL9) and IFN-gamma-inducible protein 10 (IP-10/CXCL10) in liver leukocytes and correlate their production with the infiltration of MCMV-specific CD8 T cells into the liver. Antibody-mediated neutralization of CXCL9 and CXCL10 and studies using mice deficient in CXCR3, the primary known receptor for these chemokines, revealed that CXCR3-dependent mechanisms promote the infiltration of virus-specific CD8 T cells into the liver during acute infection with MCMV. Furthermore, CXCR3 functions augmented the hepatic accumulation of CD8 T-cell IFN-gamma responses to MCMV. Evaluation of protective functions demonstrated enhanced pathology that overlapped with transient increases in virus titers in CXCR3-deficient mice. However, ultimate viral clearance and survival were not compromised. Thus, CXCR3-mediated signals support the accumulation of MCMV-specific CD8 T cells that contribute to, but are not exclusively required for, protective responses in a virus-infected tissue site.

Dengue virus induces expression of CXC chemokine ligand 10/IFN-gamma-inducible protein 10, which competitively inhibits viral binding to cell surface heparan sulfate

Dengue virus is an arthropod-borne flavivirus that causes a mild febrile illness, dengue fever, or a potentially fatal syndrome, dengue hemorrhagic fever/dengue shock syndrome. Chemokines primarily orchestrate leukocyte recruitment to the areas of viral infection, which makes them critical mediators of immune and inflammatory responses. In the present study, we investigated the induction and function of chemokines in mice early after infection with dengue virus in vivo. We found that CXCL10/IFN-gamma-inducible protein 10 (IP-10) expression was rapidly and transiently induced in liver following infection. The expressed CXCL10/IP-10 likely mediates the recruitment of activated NK cells, given that anti-CXCL10/IP-10-treated mice showed diminished NK cell infiltration and reduced hepatic expression of effector molecules in activated NK cells after dengue virus infection. Of particular interest, we found that CXCL10/IP-10 also was able to inhibit viral binding to target cells in vitro. Further investigation revealed that various CXCL10/IP-10 mutants, in which the residues that mediate the interaction between the chemokine and heparan sulfate were substituted, failed to exert the inhibitory effect on dengue binding, which suggests that CXCL10/IP-10 competes with dengue virus for binding to heparan sulfate on the cell surface. Moreover, subsequent plaque assays showed that this inhibition of dengue binding blocked viral uptake and replication. The inhibitory effect of CXCL10/IP-10 on the binding of dengue virus to cells may represent a novel contribution of this chemokine to the host defense against viral infection.

Both CXCR3 and CXCL10/IFN-inducible protein 10 are required for resistance to primary infection by dengue virus

We examined the extent to which CXCR3 mediates resistance to dengue infection. Following intracerebral infection with dengue virus, CXCR3-deficient (CXCR3(-/-)) mice showed significantly higher mortality rates than wild-type (WT) mice; moreover, surviving CXCR3(-/-) mice, but not WT mice, often developed severe hind-limb paralysis. The brains of CXCR3(-/-) mice showed higher viral loads than those of WT mice, and quantitative analysis using real-time PCR, flow cytometry, and immunohistochemistry revealed fewer T cells, CD8(+) T cells in particular, in the brains of CXCR3(-/-) mice. This suggests that recruitment of effector T cells to sites of dengue infection was diminished in CXCR3(-/-) mice, which impaired elimination of the virus from the brain and thus increased the likelihood of paralysis and/or death. These results indicate that CXCR3 plays a protective rather than an immunopathological role in dengue virus infection. In studies to identify critical CXCR3 ligands, CXCL10/IFN-inducible protein 10-deficient (CXCL10/IP-10(-/-)) mice infected with dengue virus showed a higher mortality rate than that of the CXCR3(-/-) mice. Although CXCL10/IP-10, CXCL9/monokine induced by IFN-gamma, and CXCL11/IFN-inducible T cell alpha chemoattractant share a single receptor and all three of these chemokines are induced by dengue virus infection, the latter two could not compensate for the absence of CXCL10/IP-10 in this in vivo model. Our results suggest that both CXCR3 and CXCL10/IP-10 contribute to resistance against primary dengue virus infection and that chemokines that are indistinguishable in in vitro assays differ in their activities in vivo.

Constitutive and regulated expression and secretion of interferon-gamma-inducible protein 10 (IP-10/CXCL10) in human adipocytes

OBJECTIVE

Chemokine secretion by adipocytes has been postulated to initiate leukocyte infiltration in adipose tissue and might mediate an important step in the establishment of obesity-related chronic immune activation. The chemokine interferon (IFN)gamma-inducible protein-10 (IP-10/CXCL10) is a chemoattractant for various leukocyte subsets and has been implicated in the pathogenesis of atherosclerosis. This study investigates whether IP-10 is expressed in human adipocytes and whether its release is regulated by body mass index (BMI) or immunological stimuli.

METHODS

In cultures of human mature adipocytes and in vitro differentiated adipocytes, IP-10 expression under basal conditions and in the presence of IFNgamma, lipopolysaccharide (LPS) or interleukin (IL)-4 was characterized by reverse transcriptase-polymerase chain reaction, Luminex technology and immunofluorescence.

RESULTS

IP-10 was expressed and secreted constitutively in most cultures of mature adipocytes from omental and subcutaneous (s.c.) depots. The association between IP-10 release and donor BMI was not significant. In in vitro differentiated adipocytes from s.c. and mammary depots and in mature s.c. adipocytes, IP-10 secretion was strongly upregulated by IFNgamma, whereas LPS or IL-4 did not affect IP-10 expression in s.c. mature adipocytes. Immunofluorescence confirmed IP-10 expression in adipocytes with abundant lipid droplets.

CONCLUSION

Mature human adipocytes express and secrete the chemokine IP-10 and are thus identified as a novel cellular source of this disease-related immune mediator. IP-10 expression could be significantly induced by IFNgamma, but not by LPS, which points to both similar reactivities and functional differences between adipocytes and innate immune cells.

Antagonist of interferon-inducible protein 10/CXCL10 ameliorates the progression of autoimmune sialadenitis in MRL/lpr mice

OBJECTIVE

Mononuclear cell infiltration of the salivary glands is a major feature of Sjögren's syndrome (SS) and its animal model. Local generation of chemokines and the presence of chemokine receptors on the infiltrating cells may be involved in this process. We undertook the present study to investigate the expression of chemokines during the development of autoimmune sialadenitis in MRL/lpr mice and the therapeutic effect of chemokine antagonists on sialadenitis.

METHODS

NH2-terminal-truncated interferon-inducible protein 10 (IP-10)/CXCL10 analogs were transfected into a nonmetastatic fibroblastoid cell line, MRL/N-1, and injected subcutaneously into MRL/lpr mice, and the effects on sialadenitis were monitored.

RESULTS

IP-10 analogs truncated by 5 or more amino acid residues from the N-terminal failed to induce chemotaxis and calcium influx by CXCR3-expressing cells. Of these, the most potent antagonist (AT) (IP-10-AT) was a molecule with methionine added after removal of the 5 N-terminal amino acid residues. Significantly increased expression of the Th1-associated chemokines IP-10, monokine induced by interferon-gamma/CXCL9, and interferon-inducible T cell chemoattractant/CXCL11 was induced in the ductal epithelium by interferon-gamma produced in the salivary glands, whereas expression of the Th2-associated chemokines thymus and activation-regulated chemokine (TARC)/CCL17 and monocyte-derived chemokine/CCL22 was almost undetectable during sialadenitis. Inoculation of IP-10-AT into MRL/lpr mice during the early stage of sialadenitis significantly reduced periductal mononuclear cell infiltration and parenchymal destruction compared with these features in control and TARC-AT-bearing mice. This was due to a significant reduction in infiltration of CXCR3+ T cells, predominantly Th1 cells, resulting in decreased interferon-gamma production.

CONCLUSION

We prepared a novel potent IP-10 antagonist and demonstrated its ability to ameliorate the progression of autoimmune sialadenitis. This agent may provide a new therapeutic approach to SS.

Expression of IP-10/CXCL10 Is Upregulated by Double-Stranded RNA in BEAS-2B Bronchial Epithelial Cells

BACKGROUND

Interferon (IFN)-gamma-inducible protein of 10 kDa (IP-10/CXCL10) is a potent chemoattractant for activated T and NK cells, and elevated levels of IP-10 are identified in bronchoalveolar lavage fluids from patients with pulmonary disorders related to Th-1-type immunity, which is a prerequisite for elimination of viral pathogens. Bronchial epithelial cells play an important role in respiratory infections as the initiator of airway inflammation by releasing chemokines and expressing cell surface membrane molecules involved in leukocyte adhesion. Polyinosinic-polycytidylic acid (poly IC) is a synthetic double-stranded RNA (dsRNA) and induces antiviral reactions in cells.

OBJECTIVES

We investigated the regulation of IP-10 in BEAS-2B bronchial epithelial cells in response to poly IC, and also addressed the possible role of retinoic-acid-inducible gene-I (RIG-I) and IFN-regulatory factor 3 (IRF-3), two genes involved in the signaling induced by viral infection.

METHODS

The expressions of IP-10 mRNA and protein were analyzed by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. The overexpression of RIG-I or IRF-3 was performed by transfection of BEAS-2B cells with each cDNA.

RESULTS

Poly IC enhanced the expression of IP-10 mRNA and protein in concentration- and time-dependent manners. Overexpression of RIG-I or IRF-3 potentiated the poly-IC-induced upregulation of IP-10.

CONCLUSIONS

IP-10 may contribute to antiviral activity through the activation of Th-1-type immunity, and RIG-I and IRF-3 may be involved in this reaction.

Effects of HeNe laser irradiation on experimental paracoccidioidomycotic lesions

Paracoccidioidomycosis (PCM) is the most prevalent human mycosis in Latin America. The infection is thought to take place firstly in the lungs and then may disseminate to other organs and tissues. Treatment by currently available antifungals is lengthy, the drugs may have undesirable side effects, and some are costly. Occasional resistant strains of Paracoccidioides brasiliensis, the causative agent of PCM, have been reported. So, the search for more efficient treatments or adjuvant therapies has to be continued. In this work, we evaluated the effects of HeNe laser irradiation on cutaneous inflammatory lesions caused by the inoculation of 5 x 10(6)/0.1ml yeasts cells into the back footpad of Balb/c mice. HeNe irradiation (lambda=632.8nm, 3mW, incident energy of 3J/cm(2)) was applied at days 7, 8 and 9 post-infection and histological and immunohistochemical analysis were done. Unirradiated animals were used as controls. The results showed that laser-treated mice presented reduction of footpad edema, faster cutaneous wound healing, confluent granuloma, diffuse- and more loosely distributed immunolabeling for TNF-alpha, enhanced labeling of IFN-gamma and any P. brasiliensis form detected, whereas multiple viable fungi were seen in diffuse widespread granulomas obtained from non-treated mice foot-pad. Fungi that were harvested from laser-treated animals presented no capability of growth in vitro as compared to those obtained from non-treated mice. We conclude that HeNe laser irradiation was able to inhibit the progress of inflammatory local reaction produced by P. brasiliensis infection and influence local cytokines production. We suggest that this treatment modality can be a useful coadjuvant tool to be combined with antifungal agents in the treatment of PCM ulcerations. The mechanisms involved in laser therapy of PCM lesions need further investigation.

Chemokine receptor deficiency is associated with increased chemokine expression in the peripheral and central nervous systems and increased resistance to herpetic encephalitis

Herpes simplex virus type 1 (HSV-1) infection of the eye leads to the retrograde spread of the virus from the eye to the trigeminal ganglion resulting in the infiltration of leukocytes and production of inflammatory cytokines and chemokines including CXCL9 and CXCL10. The present study investigated the role of the receptor for CXCL9 and CXCL10 in the host response to HSV-1 infection using mice deficient in CXCR3 expression (CXCR3-/-). Although wild type C57BL/6 and CXCR3-/- mice cleared the virus, HSV-1 titers remained elevated in the ganglion and brain stem of CXCR3-/- mice day 7 post infection. Coinciding with the increase in virus titer, CCL5, CXCL9, CXCL10 and IFN-gamma protein levels were enhanced in the trigeminal ganglion and/or brain stem of the CXCR3-/- mice associated with a 2-fold increase in the percentage of CD3+CD8+ T lymphocytes in the trigeminal ganglion. However, the survival rate of CXCR3-/- mice was significantly enhanced above the wild type controls associated with an increase in brain IL-6 content. Collectively, the results indicate the absence of CXCR3 is associated with a transient increase in virus burden in the nervous system and an elevated protective immune response.

Roles for CXC chemokine ligands 10 and 11 in recruiting CD4+ T cells to HIV-1-infected monocyte-derived macrophages, dendritic cells, and lymph nodes

We investigated roles for chemoattractants in dissemination of HIV-1 by examining the induction of T cell-active chemokines in HIV-1-infected human monocyte-derived macrophages and dendritic cells. Of the 12 chemokines analyzed, mRNAs for two, CXCL10 and CXCL11, ligands for the chemokine receptor CXCR3, were up-regulated in both cell types upon infection by HIV-1. Induction of these chemokine genes in infected cultures was dependent on both viral entry and reverse transcriptase activity, but not on the HIV-1 envelope glycoprotein. Conditioned medium from infected cells was chemotactic for freshly isolated human CD4+ T cells, and chemotaxis was abolished by pretreatment with an Ab against CXCR3. A lymph node from an HIV-1-infected individual expressed CXCL10 and CXCL11 mRNAs in the paracortex, including venules, as detected by in situ hybridization, whereas neither mRNA was detected after highly active antiretroviral therapy. Because CCR5 on CD4+ T cells is found predominantly on cells that also express CXCR3, these data implicate CXCL10 and CXCL11 in the recruitment of susceptible T cells to HIV-1-infected lymph nodes, macrophages, and dendritic cells. This recruitment might enhance the sequestration of T cells in infected lymphoid organs and the spread of infection between cells, contributing to the immunopathology of AIDS.

Noise overstimulation induces immediate early genes in the rat cochlea

In mammals, exposure to intense noise produces a permanent hearing loss called permanent threshold shift (PTS), whereas a moderate noise produces only a temporary threshold shift (TTS). Little is known about the molecular responses to such high intensity noise exposures. In this study we used gene arrays to examine the early response to acoustic overstimulation in the rat cochlea. We compared cochlear RNA from noise-exposed rats with RNA from unexposed controls. The intense PTS noise induced several immediate early genes encoding both transcription factors (c-FOS, EGR1, NUR77/TR3) and cytokines (PC3/BTG2, LIF and IP10). In contrast, the TTS noise down-regulated the gene for growth hormone. The response of these genes to different noise intensities was examined by quantitative RT-PCR 2.5 h after the 90-min noise exposure. For most genes, the extent of induction correlates with the intensity of the noise exposure. Three proteins (EGR1, NUR77/TR3, and IP10) were detected in many regions of the unexposed cochlea. After exposure to 120 dB noise, these proteins were present at higher levels or showed extended expression in additional regions of the cochlea. LIF was undetectable in the cochlea of unexposed rats, but could be seen in the organ of Corti and spiral ganglion neurons following noise. NUR77/TR3 was a nuclear protein before noise, but following noise translocated to the cytoplasm. These studies provide new insights into the molecular response to noise overstimulation in the mammalian cochlea.

Human immunodeficiency virus type 1 Nef protein mediates neural cell death: a neurotoxic role for IP-10

HIV-1 Nef is expressed in astrocytes, but a contribution to neuropathogenesis and the development of HIV-associated dementia (HAD) remains uncertain. To determine the neuropathogenic actions of the HIV-1 Nef protein, the brain-derived (YU-2) and blood-derived (NL4-3) Nef proteins were expressed in neural cells using an alphavirus vector, which resulted in astrocyte death (P < 0.001). Supernatants from Nef-expressing astrocytes also caused neuronal death, suggesting the release of neurotoxic molecules by astrocytes. Analysis of pro-inflammatory gene induction in astrocytes expressing Nef revealed increased IP-10 mRNA expression (4000-fold) that was Nef sequence dependent. Recombinant IP-10 caused selective cell death in neurons (P < 0.001) but not astrocytes, and the cytotoxicity of supernatant from astrocytes expressing Nef YU-2 was blocked by an antibody directed against the chemokine receptor CXCR3 (P < 0.001). SCID/NOD mice implanted with a Nef YU-2-expressing vector displayed abnormal motor behavior (P < 0.05), neuroinflammation, and neuronal loss relative to controls. Analysis of mRNA levels in brains from patients with HAD also revealed increased expression of IP-10 (P < 0.05), which was confirmed by immunoreactivity detected principally in astrocytes. Phylogenetic and protein structure analyses of Nef sequences derived from HIV/AIDS patients with and without HAD suggested viral evolution toward a neurotropic Nef protein. These results indicate that HIV-1 Nef contributes to neuropathogenesis by directly causing astrocyte death together with indirect neuronal death through the cytotoxic actions of IP-10 on neurons. Furthermore, Nef molecular diversity was evident in brain tissue among patients with neurological disease and which may influence IP-10 production by astrocytes.

TLR activation synergizes with Kilham rat virus infection to induce diabetes in BBDR rats

Virus infection is hypothesized to be an important environmental "trigger" of type 1 diabetes in humans. We used the BBDR rat model to investigate the relationship between viral infection and autoimmune diabetes. BBDR rats are diabetes-free in viral Ab-free housing, but the disease develops in approximately 30% of BBDR rats infected with Kilham rat virus (KRV) through a process that does not involve infection of pancreatic beta cells. Pretreatment with polyinosinic-polycytidylic (poly(I:C)), a ligand of TLR3, acts synergistically to induce diabetes in 100% of KRV-infected rats. The mechanisms by which KRV induces diabetes and TLR3 ligation facilitates this process are not clear. In this study, we demonstrate that activation of the innate immune system plays a crucial role in diabetes induction. We report that multiple TLR agonists synergize with KRV infection to induce diabetes in BBDR rats, as do heat-killed Escherichia coli or Staphylococcus aureus (natural TLR agonists). KRV infection increases serum IL-12 p40 in a strain-specific manner, and increases IL-12 p40, IFN-gamma-inducible protein-10, and IFN-gamma mRNA transcript levels, particularly in the pancreatic lymph nodes of BBDR rats. Infection with vaccinia virus or H-1 parvovirus induced less stimulation of the innate immune system and failed to induce diabetes in BBDR rats. Our results suggest that the degree to which the innate immune system is activated by TLRs is important for expression of virus-induced diabetes in genetically susceptible hosts.

A General Survey of Thymocyte Differentiation by Transcriptional Analysis of Knockout Mouse Models

The thymus is the primary site of T cell lymphopoiesis. To undergo proper differentiation, developing T cells follow a well-ordered genetic program that strictly depends on the heterogeneous and highly specialized thymic microenvironment. In this study, we used microarray technology to extensively describe transcriptional events regulating alphabeta T cell fate. To get an integrated view of these processes, both whole thymi from genetically engineered mice together with purified thymocytes were analyzed. Using mice exhibiting various transcriptional perturbations and developmental blockades, we performed a transcriptional microdissection of the organ. Multiple signatures covering both cortical and medullary stroma as well as various thymocyte maturation intermediates were clearly defined. Beyond the definition of histological and functional signatures (proliferation, rearrangement), we provide the first evidence that such an approach may also highlight the complex cross-talk events that occur between maturing T cells and stroma. Our data constitute a useful integrated resource describing the main gene networks set up during thymocyte development and a first step toward a more systematic transcriptional analysis of genetically modified mice.

A novel fusion protein of IP10-scFv retains antibody specificity and chemokine function

We combined the specificity of tumor-specific antibody with the chemokine function of interferon-gamma inducible protein 10 (IP-10) to recruit immune effector cells in the vicinity of tumor cells. A novel fusion protein of IP10-scFv was constructed by fusing mouse IP-10 to V(H) region of single-chain Fv fragment (scFv) against acidic isoferritin (AIF), and expressed in NS0 murine myeloma cells. The IP10-scFv fusion protein was shown to maintain the specificity of the antiAIF scFv with similar affinity constant, and bind to the human hepatocarcinoma SMMC 7721 cells secreting AIF as well as the activated mouse T lymphocytes expressing CXCR3 receptor. Furthermore, the IP10-scFv protein either in solution or bound on the surface of SMMC 7721 cells induced significant chemotaxis of mouse T cells in vitro. The results indicate that the IP10-scFv fusion protein possesses both bioactivities of the tumor-specific antibody and IP-10 chemokine, suggesting its possibility to induce an enhanced immune response against the residual tumor cells in vivo.

VIP/PACAP preferentially attract Th2 effectors through differential regulation of chemokine production by dendritic cells

The neuropeptides vasoactive intestinal peptide (VIP) and the structurally related pituitary adenylate cyclase-activating polypeptide (PACAP) are potent immunomodulatory agents, acting as general anti-inflammatory factors. VIP, produced and secreted by Th2 cells following antigen stimulation, participates in a Th2 autoregulatory loop, promoting Th2-type responses through several nonexcluding mechanisms. VIP and PACAP affect the differentiation of CD4+ T cells directly and indirectly through antigen-presenting cells and promote the proliferation and/or survival of the Th2 effectors. Th1 and Th2 effectors express different chemokine receptors that control migration in response to various chemokines. In this study, we investigated the effects of VIP/PACAP on the production of CXCL10 (a Th1 chemokine) and of CCL22 (a Th2 chemokine) by bone marrow-derived dendritic cells. We found that VIP and PACAP inhibit CXCL10, while promoting CCL22 production, and that the effects are mediated through the VPAC1 receptor and involve cAMP/PKA as intracellular messengers. The induction of CCL22 and the suppression of CXCL10 in VIP/PACAP-treated dendritic cells results in the preferential chemoattraction of Th2 effectors both in vivo and in vitro. This is in agreement with the general Th2 bias induced by the two neuropeptides and adds an important parameter to their immunomodulatory function. By promoting Th2 migration, and preventing or reducing Th1 infiltration in inflammatory foci and sites of antigen presentation, VIP and PACAP help in resolving acute inflammatory processes and contribute to the prevention of chronic inflammation.

Measles virus infection induces chemokine synthesis by neurons

The role that neurons play in the induction of the immune response following CNS viral infection is poorly understood, largely owing to the belief that these cells are immunologically quiescent. In this report, we show that virus infection of neurons results in the synthesis of proinflammatory chemokines, which are early and important mediators of leukocyte recruitment to sites of viral infection. For these studies, a transgenic mouse model of neuron-restricted measles virus (MV) infection was used. Inoculation of immunocompetent and immunodeficient transgenic adult mice resulted in CNS induction of the mRNAs encoding IFN-gamma inducible protein of 10 kD, monokine inducible by gamma and RANTES. Colocalization of chemokine proteins with MV-infected neurons was detected by immunofluorescence in infected brain sections. Both IFN-gamma inducible protein 10 kD and RANTES were also induced in MV-infected primary hippocampal neurons cultured from transgenic embryos, as shown by RNase protection assay, confocal microscopy, and ELISA. Interestingly, neuronal infection with another RNA virus (lymphocytic choriomeningitis virus) was not associated with induction of these chemokines. In immunocompetent mice, chemokine synthesis preceded the infiltration of T lymphocytes, and chemokine ablation by neutralizing Abs resulted in a 20-50% reduction in the number of infiltrating lymphocytes. Collectively, these data indicate that neurons play an important role in the recruitment of a protective antiviral response to the CNS following viral infection, although such a role may be virus type-dependent.

Regulation of the C-X-C chemokine, mob-1, gene expression in primary rat hepatocytes

The chemokine, mob-1, is involved in inflammatory and immune responses and may be an important mediator of the inflammatory response in the liver. Here, we investigated the upstream signal pathways that could be involved in the regulation of mob-1 expression. We have found that in primary rat hepatocytes the isolation and subsequent culture of these cells induced mob-1 expression. A similar induction of mob-1 mRNA was observed when the hepatocytes were stimulated with interferon-gamma (IFN-gamma). When hepatocytes were stimulated with IFN-gamma or cytokine mixture (IFN-gamma, interleukin-1beta and tumour necrosis factor-alpha), c-Jun N-terminal kinase (JNK), p38 and extracellular-regulated kinase (ERK) were phosphorylated, suggesting an involvement of the mitogen-activated protein kinases (MAPK) in the induction of mob-1 expression. The p38 kinase inhibitor, SB 203580, and the NF-kappaB inhibitor, MG-132, inhibited the induction of mob-1 mRNA and the effects were not additive. These results demonstrate that in primary rat hepatocytes the transient induction of mob-1 expression was regulated by p38 kinase and NF-kappaB through a common regulatory pathway.

Inhibition of interferon (IFN) gamma-induced Jak-STAT1 activation in microglia by vasoactive intestinal peptide: inhibitory effect on CD40, IFN-induced protein-10, and inducible nitric-oxide synthase expression

Interferon (IFN)-gamma is one of the most important microglia stimulators in vivo participating in inflammation and Th1 activation/differentiation. IFN-gamma-mediated signaling involves the activation of the Jak/STAT1 pathway. The neuropeptides vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase activating polypeptide (PACAP) are two potent microglia-deactivating factors that inhibit the production of proinflammatory mediators in vitro and in vivo. The present study investigated the molecular mechanisms involved in the VIP/PACAP regulation of several IFN-gamma-induced microglia-derived factors, including IFN-gamma-inducible protein-10 (IP-10), inducible nitric-oxide synthase (iNOS), and CD40. The results indicate that VIP/PACAP inhibit Jak1-2 and STAT1 phosphorylation, and the binding of activated STAT1 to the IFN-gamma activated site motif in the IFN regulatory factor-1 and CD40 promoter and to the IFN-stimulated response element motif of the IP-10 promoter. Through its effect in the IFN-gamma-induced Jak/STAT1 pathway, VIP and PACAP are able to control the gene expression of IP-10, CD40, and iNOS, three microglia-derived mediators that play an essential role in several pathologies, i.e. inflammation and autoimmune disorders. The effects of VIP/PACAP are mediated through the specific receptor VPAC1 and the cAMP/protein kinase A transduction pathway. Because IFN-gamma is a major stimulator of innate and adaptive immune responses in vivo, the down-regulation of IFN-gamma-induced gene expression by VIP and PACAP could represent a significant element in the regulation of the inflammatory response in the central nervous system by endogenous neuropeptides.

Transcriptional and posttranscriptional control of hepatitis B virus gene expression

Hepatitis B virus (HBV) infects humans and certain nonhuman primates. Viral clearance and acute disease are associated with a strong, polyclonal, multispecific cytotoxic T lymphocyte response. Infiltrating T cells, as well as other activated inflammatory cells, produce cytokines that can regulate hepatocellular gene expression. Using an HBV transgenic mouse model, our laboratory has previously demonstrated that adoptive transfer of HBV-specific cytotoxic T lymphocytes or injection of IL-2 can noncytopathically inhibit HBV gene expression by a posttranscriptional IFN-gamma- and/or tumor necrosis factor alpha-dependent mechanism. Here, we report that HBV gene expression can also be controlled at the posttranscriptional level during persistent lymphocytic choriomeningitis virus infection. In contrast, it is controlled at the transcriptional level during acute murine cytomegalovirus infection or after repetitive polyinosinic-polycytidylic acid injection. Finally, we show that transcriptional inhibition of HBV is associated with changes in liver-specific gene expression. These results elucidate pathways that regulate the viral life cycle and suggest additional approaches for the treatment of chronic HBV infection.

Beta cells are responsible for CXCR3-mediated T-cell infiltration in insulitis

T cell-mediated loss of insulin-secreting beta cells in the islets of Langerhans is the hallmark of type 1 diabetes. The molecular basis for the directed migration of autoreactive T cells leading to insulitis is presently unknown. Here we demonstrate that in response to inflammation, beta cells secrete the chemokines CXC ligand 10 and CXC ligand 9, which specifically attract T-effector cells via the CXC chemokine receptor 3. In mice deficient for this receptor, the onset of type 1 diabetes is substantially delayed. Thus, in the absence of known etiological agents, CXC receptor 3 represents a novel target for therapeutic interference early in type 1 diabetes.

VIP and PACAP down-regulate CXCL10 (IP-10) and up-regulate CCL22 (MDC) in spleen cells

The immunoregulatory neuropeptides VIP and PACAP favor Th2-type immune responses. Antigen-stimulated Th2 cells produce VIP, VIP/PACAP induce Th2 cytokine responses, and promote the preferential survival of Th2 effectors. In this study, we investigate the effects of VIP/PACAP on two chemokines, i.e. CXCL10 (IP-10) acting on CXCR3 expressed on activated Th1 cells, and CCL22 (MDC) acting on CCR4 and 8 expressed on activated Th2 cells. VIP and PACAP down-regulate CXCL10, and up-regulate CCL22 in vivo and in vitro. The effects on the two chemokines appear to be different in mechanistic terms. The fact that VIP/PACAP might promote the directed migration of Th2 cells adds a new dimension to their participation in the Th2 auto-regulatory loop.

NF-kappa B activation mediates the cross-talk between extracellular matrix and interferon-gamma (IFN-gamma) leading to enhanced monokine induced by IFN-gamma (MIG) expression in macrophages

In intact tissue, the extracellular matrix (ECM) provides support and helps maintain homeostasis but is considered biologically inert. In the setting of inflammation, not only is the ECM the target of inflammation, but its breakdown products modulate the magnitude and quality of an immune response. Fragments of the ECM component hyaluronan (HA) induce macrophage expression of chemokines, cytokines, and growth factors as well greatly enhance IFN-gamma-induced MIG expression. In this report, we demonstrate that the synergistic induction of MIG by HA and IFN-gamma occurs at the level of transcription via NF-kappaB. Using electrophoretic mobility shift assays and reporter assays, we have identified two NF-kappaB sites proximal to the IFN-gamma-responsive element-1 (gammaRE-1) that mediate this effect. Interestingly, our experiments also revealed a critical role for NF-kappaB in mediating IFN-gamma-induced MIG expression independent of HA. These data emphasize the ability of "degraded self" to activate/modify immune responses through the NF-kappaB pathway.