IFN-gamma-inducible Protein 10 Research Articles

IL-17 Imbalance Promotes the Pyroptosis in Immune-Mediated Liver Injury Through STAT3-IFI16 Axis.

Autoimmune hepatitis (AIH) affects all age group and occurs mainly in women. Pyroptosis is a novel programmed cell death featured with cell bursting and release of proinflammatory cytokines. A deeper understanding of AIH pathogenesis will contribute to novel therapy for AIH patients. Here, we aimed to investigate the role of IL-17 in immune-mediated liver injury. The levels of cytokines were measured by ELISA, and mRNA levels of STAT3 and IFN gamma-inducible protein 16 (IFI16) were detected by PCR. Expressions of STAT3, IFI16, gasdermin D and cleaved caspase-1 were measured by western-blotting. Immunohistochemical staining and transmission electron microscopy were applied to evaluate liver histopathological changes of the treated mice. Our results showed that the levels of IFI16 was increased in hepatocytes treated with IL-17 protein, and further elevated after STAT3-overexpressed (STAT3-OE) lentivirus treatment. The levels of IFI16 were reduced in hepatocytes treated with IL-17 neutralizing Ab (nAb), but were significantly increased after STAT3-OE treatment. Pyroptosis was observed in hepatocytes treated with IL-17 protein, and further cell damage was observed after STAT3-OE lentivirus treatment. Liver damage was alleviated in mice treated with IL-17 nAb, however sever damage was experienced after STAT3-OE lentivirus treatment. A binding interaction between IFI16 and STAT3 was detected in IL-17 treated hepatocytes. Glutathione transaminase activity was enhanced in concanavalin A-induced AIH mice compared to the control group (p<0.01). IL-17 plays an important role in activating STAT3 and up-regulating IFI16, which may promote the pyroptosis in AIH-related liver injury through STAT3-IFI16 axis.

Underlying Mechanism for Stimulated GMP Formation in a Unique Large GTPase hGBP1

Unlike other GTPases, IFN-gamma inducible large GTPase human guanylate binding protein 1 (hGBP1) has a unique property of hydrolyzing GTP to both GDP and GMP through successive cleavages of the two phosphates. This protein is involved in immunity against several viruses. In the absence of the full-length hGBP1 structure with substrate in dimeric state, the mechanism of GTP hydrolysis was elucidated using the dimeric structure of truncated hGBP11-317(contains only catalytic domain) with various analogs.

Metataxonomic and immunological analysis of milk from ewes with or without a history of mastitis

Mastitis is a highly prevalent condition that has a great impact on milk production and animal welfare, and often requires substantial management efforts. For this reason, it is generally considered an important threat to the dairy industry. Many microbial, host, and environmental factors can protect against, predispose to, or influence the development of mastitis. The objective of this work was to characterize the milk microbiota of Manchega ewes, and to compare samples from animals with and without a history of mastitis. We analyzed milk samples from 36 ewes belonging to 2 different farms (18 ewes from each farm) using culture-dependent and culture-independent techniques. We also analyzed several immune compounds to investigate associations of mastitis with 3 main variables: farm; history of mastitis or no mastitis; and parity number. Both culture-dependent and culture-independent techniques showed that ewe milk harbored a site-specific complex microbiota and microbiome. Staphylococcus epidermidis was the main species driving the difference between farm A (where it was the dominant species) and B (where it was not). In contrast, samples from farm B were characterized by the presence of a wide spectrum of other coagulase-negative staphylococci. Some of these species have already been associated with subclinical intramammary infections in ruminants. Of the 10 immune compounds assayed in this study, 3 were related to a history of mastitis [IL-8, IFN-γ, and IFN-gamma-induced protein 10 (IP-10)]. Increases in IL-8 concentrations in milk seemed to be a feature of subclinical mastitis in sheep, and in this study, this immune factor was detected only in samples from ewes with some episodes of mastitis and from the group with the highest somatic cell count. We also observed a positive correlation between the samples with the highest somatic cell count and IFN-γ and IP-10 levels. Our results suggest that these 3 compounds could be used as biomarkers for the negative selection of mastitis-prone animals, particularly when somatic cell count is very high.

CGAS enhances the HTLV-1 reverse transcription intermediate ssDNA90-induced innate immune responses

Objective To investigate the role of cyclic GMP-AMP synthase (cGAS), a cytosolic DNA sensor, in regulating innate immune responses induced by reverse transcription intermediate of human T cell leukemia virus type 1 (HTLV-1). Methods (1)ssDNA90, the reverse transcription intermediate of HTLV-1, was transfected into HeLa cells to observe changes in the expression pattern of cGAS in transfected-HeLa cells with immunoblot assay.(2)HeLa cells were firstly transfected with cGAS-encoding plasmid and then ssDNA90 24 hours later.Real-time PCR was used to measure the expression of interferon (IFN)-β, IFN-gamma-inducible protein 10 (IP-10), regulated on activation, normal T cell expressed and secreted (RANTES) and tumor necrosis factor (TNF)-α.Immunoblot assay was performed to measure phosphorylated interferon regulatory factor 3 (IRF3) and p65.(3)cGAS expression was silenced by siRNA in HeLa and phorbol-12-myristate-13-acetate (PMA)-treated THP1 (PMA-THP1) cells and then ssDNA90 was transfected into these cells 24 hours later.Real-time PCR was used to measure the expression of IFN-β, IP-10, RANTES and TNF-α.Immunoblot assay was performed to measure phosphorylated IRF3 and p65. Results Expression of cGAS was increased in HeLa cells after ssDNA90 transfection.Compared with control cells, cGAS-transfected HeLa cells showed increased expression of IFN-β, IP-10, RANTES and TNF-α and enhanced phosphorylation of IRF3 and p65 after ssDNA90 transfection.Compared with control cells, both HeLa and PMA-THP1 cells with silenced expression of cGAS showed impaired production of IFN-β, IP-10, RANTES and TNF-α after ssDNA90 transfection.Moreover, ssDNA90-induced phosphorylation of IRF3 and p65 were decreased after cGAS gene-knockdown. Conclusion cGAS might promote HTLV-1 RTI ssDNA90-induced innate immune responses. Key words: cGAS; HTLV-1; DNA sensor; Reverse transcription intermediate; Innate immune response

Identifying novel mechanisms regulating the expression of the inflammatory chemokine IP-10

Abstract In response to the innate immune signals, mammalian cells produce inflammatory cytokines and chemokines to activate the immune system, and their expression is tightly regulated. IFN-gamma Inducible Protein (IP-10), also known as C-X-C motif chemokine 10 (CXCL10), is an inflammatory chemokine belonging to the CXC chemokine family. IP-10 is chemotactic for neutrophils, and altered expression of IP-10 is associated with many inflammatory diseases. Fli-1 belongs to the ETS transcription factor family. We have demonstrated that the Fli-1 transcription factor is a novel regulator in modulating the expression of many inflammatory mediators, including monocyte chemotactic protein 1 (MCP-1), chemokine (C-C motif) ligand 5 (CCL5) and interleukin 6 (IL-6). In this report, we found that murine endothelial cells transfected with Fli-1 specific siRNA produced significantly lower IP-10 after stimulation with Toll-like receptor 4 ligand LPS compared to the cells transfected with control siRNA. The production of IP-10 in endothelial cells with LPS stimulation is dose-dependent. We demonstrated that Fli-1 binds to the IP-10 promoter by Chromatin immunoprecipitation (ChIP) assay. Mechanisms by which Fli-1 regulates expression of IP-10 are currently being investigated. Together, the results indicate that Fli-1 is a novel, critical transcription factor in regulating the expression of the pro-inflammatory chemokine IP-10

Deficiency of the c-JUN Inhibitor DACH1 in FA Macrophages Accounts for the Cytokine Overproduction Phenotype

▪The inflammatory cytokines TNFα and IL-1β contribute to the bone marrow failure phenotype in Fanconi anemia (FA) as well as to clonal evolution to MDS and AML. Mononuclear phagocytes deficient in FANCA or FANCC overproduce these cytokines in response to toll-like receptor agonists (TLRa), but the precise molecular mechanisms by which FA proteins suppress cytokine production remains enigmatic. We show here that pretreatment of control macrophages with interferon (IFN) α enhances (by 3-fold) TLRa-induced production of both TNFα and IL-1β. FANCC-deficient cells produce more of these proteins (by 3-fold) after exposure to TLRa alone and IFNα does not enhance production of these cytokines. We therefore hypothesized that TLR stimulation of FANCC-deficient cells activates an IFNα-like pathway, one constrained by FANCC in normal cells. To test this notion, we performed gene expression microarray analysis (Affymetrix HTA 2.0) using RNA from FANCC-deficient (T-shFC) and control (T-shNT) THP-1 human mononuclear phagocytes treated with IFNα, the TLR7/8 agonist R848, or a combination of IFNα plus R848. We found that treatment of T-shFC cells with R848 alone was sufficient to enhance expression of 49 genes that were activated by IFNα in control cells. Thirteen of these genes were not induced by R848 in control cells but were induced by R848 in T-shFC cells (one of which, IFNgamma-inducible protein 30 (IFI30), is known to be overexpressed in Fancd2 -/- progenitor cells). These results support our hypothesis that FANCC functions normally to constrain IFNα pathway activation in TLRa-activated macrophages. Of greater functional importance vis-à-vis cytokine production, DACH1 mRNA was suppressed by 11-fold and DACH1 protein was barely detectable in FANCC-deficient cells under all conditions when compared to control cells. DACH1 is known to bind to and suppress the activities of a variety of transcription factors, notably c-JUN in fibroblasts. We tested the hypothesis that DACH1 deficiency is sufficient to account for the TLRa hypersensitivity of FA macrophages using gain- and loss-of-function studies. Knockdown of DACH1 in control (T-shNT) macrophages resulted in a 7-fold enhancement of R848-induced TNFα production, increased c-JUN protein (1.6-fold) and c-JUN phosphorylation (2.6-fold). Reporter gene expression (secreted embryonic alkaline phosphatase [SEAP]) from constructs containing both AP-1 and NF-κB sites was activated by DACH1 knockdown but deletion of the AP-1 site completely abrogated activation. Results of gain-of-function experiments with wild-type and mutant DACH1 cDNA sequences now taking place will be reported. Taken together, these results suggest that FANCC directly or indirectly enhances ground-state expression of DACH1 and thereby suppresses the TLR pathway in normal cells specifically by inhibiting R848-dependent activation of c-JUN. Conversely, loss of DACH1 expression in FANCC-deficient cells leads to unconstrained c-JUN activity, resulting in overproduction inflammatory cytokines. In light of the contribution of such cytokines to both bone marrow failure and clonal evolution, activation of DACH1 gene expression is a rational therapeutic objective in the management of patients with Fanconi anemia and is worthy of investigating in preclinical (animal) models. DisclosuresNo relevant conflicts of interest to declare.

Tofacitinib regulates synovial inflammation in psoriatic arthritis, inhibiting STAT activation and induction of negative feedback inhibitors

BackgroundPsoriatic arthritis (PsA) is a chronic inflammatory disease, characterised by synovitis and destruction of articular cartilage/bone. Janus-kinase and signal transducer and activator of transcription (JAK-STAT) signalling pathway is implicated in...

Immunohistochemical profiling of the heat shock response in obese non-diabetic subjects revealed impaired expression of heat shock proteins in the adipose tissue.

BackgroundObesity is characterized by a chronic low-grade inflammation and altered stress responses in key metabolic tissues. Impairment of heat shock response (HSR) has been already linked to diabetes and insulin resistance as reflected by decrease in heat shock proteins (HSPs) expression. However, the status of HSR in non-diabetic human obese has not yet been elucidated. The aim of the current study was to investigate whether obesity triggers a change in the HSR pattern and the impact of physical exercise on this pattern at protein and mRNA levels.MethodsTwo groups of adult non-diabetic human subjects consisting of lean and obese (n = 47 for each group) were enrolled in this study. The expression pattern of HSP-27, DNAJB3/HSP-40, HSP-60, HSC-70, HSP72, HSP-90 and GRP-94 in the adipose tissue was primarily investigated by immunohistochemistry and then complemented by western blot and qRT-PCR in Peripheral blood mononuclear cells (PBMCs). HSPs expression levels were correlated with various physical, clinical and biochemical parameters. We have also explored the effect of a 3-month moderate physical exercise on the HSPs expression pattern in obese subjects.ResultsObese subjects displayed increased expression of HSP-60, HSC-70, HSP-72, HSP-90 and GRP-94 and lower expression of DNAJB3/HSP-40 (P < 0.05). No differential expression was observed for HSP-27 between the two groups. Higher levels of HSP-72 and GRP-94 proteins correlated positively with the indices of obesity (body mass index and percent body fat) and circulating levels of IFN-gamma-inducible protein 10 (IP-10) and RANTES chemokines. This expression pattern was concomitant with increased inflammatory response in the adipose tissue as monitored by increased levels of Interleukin-6 (IL-6), Tumor necrosis factor-α (TNF-α), and RANTES (P < 0.05). Physical exercise reduced the expression of various HSPs in obese to normal levels observed in lean subjects with a parallel decrease in the endogenous levels of IL-6, TNF-α, and RANTES.ConclusionTaken together, these data indicate that obesity triggers differential regulation of various components of the HSR in non-diabetic subjects and a 3-month physical moderate exercise was sufficient to restore the normal expression of HSPs in the adipose tissue with concomitant attenuation in the inflammatory response.

CXCR3 axis in patients with primary biliary cirrhosis: a possible novel mechanism of the effect of ursodeoxycholic acid

The CXC chemokines, monokine induced by interferon (IFN)-gamma (MIG) (CXCL9), IFN-gamma-induced protein 10 (IP-10) (CXCL10) and IFN-inducible T cell alpha chemoattractant (I-TAC) (CXCL11), are known to attract CXCR3- (CXCR3A and CXCR3B) T lymphocytes. We investigated MIG, IP-10 and I-TAC mRNAs expression by semi-quantitative multiplex reverse transcription-polymerase chain reaction (RT-PCR) in liver biopsies obtained from patients with a first diagnosis of primary biliary cirrhosis [(PBC) = 20] compared to patients with normal liver biopsy [normal controls (NCs) = 20]. Chemokine production was assessed by enzyme-linked immunosorbent assay (ELISA) in serum. Measurements were repeated 6 months after ursodeoxycholic acid (UDCA) treatment in PBC patients. CXCR3A and CXCR3B mRNAs expression was examined in immunomagnetically sorted CD3(+) peripheral blood lymphocytes (PBL) pre- and post-treatment by RT-PCR. Flow cytometry was used to evaluate the expression of CXCR3(+) PBLs of NCs and PBC patients. A marked mRNA expression of MIG and IP-10 was found in PBC patients. I-TAC mRNA was not detected. In serum of PBC patients there was a significant increase of MIG and IP-10 compared to NCs. Interestingly, there was a significant reduction of these proteins in patients' serum after UDCA treatment. I-TAC was not statistically different between groups. CXCR3A mRNA expression was found in PBLs from PBC patients as well as in NCs. CXCR3B mRNA was expressed in four of 20 (19%) NCs and 20 of 20 PBC patients. Flow cytometry revealed a significantly lower CXCR3 expression in NCs (13·5%) than in PBC (37·2%), which was reduced (28·1%, P < 0·01) after UDCA administration. These data suggest a possible role for CXCR3-binding chemokines and their receptor in the aetiopathogenetic recruitment of lymphocytes in PBC and a new mechanism of action for UDCA.

Abstract A15: IFN-gamma-inducible-protein-10 stimulates intratumoral infiltration of adoptively transferred human NK cells in a melanoma xenograft mouse model.

Abstract Aim: In the present study, we investigated whether adoptively transferred human NK cells would migrate towards IP-10 producing melanoma tumors in a xenograft mouse model. Moreover, we assessed the effect of the chemotherapeutic agent doxorubicin in increasing the sensitivity of IFNγ-treated tumors to NK cell lysis in vitro and in vivo. Background: Adoptive transfer of natural killer (NK) cells is being increasingly used in the treatment of cancer. However, clinical trials involving adoptive transfer of NK cells have to date been more successful against leukemia and other blood-borne cancers than against solid tumors. Several groups have reported that intratumoral infiltration of NK cells correlates with improved prognosis in patients with solid tumors. Recruitment and infiltration and of NK cells in the tumor is dependent on the production of IFN-gamma-inducible-protein-10 (IP-10) by tumor cells. Although tumor cells can be triggered to produce IP-10 by IFNγ stimulation, the expression of MHC class I is increased on tumor cells resulting in decreased sensitivity to NK cell lysis. Results: Following activation with IL-2, human NK cells upregulated the chemokine receptor CXCR3 resulting in significantly increased migration toward recombinant IP-10, MIG and I-TAC in a transwell migration assay (p=0.03). Expanded NK cells also migrated toward melanoma tumor cells that had been stimulated with IFNγ to induce secretion of IP-10 (p&amp;lt;0.01). In an in vivo xenograft model, an increased accumulation of adoptively infused human NK cells could be detected in subcutaneous melanoma tumors transfected with IP-10 while IP-10 negative tumors had little or no NK cell infiltration (p=0.02). Following infusion of expanded NK cells, significantly reduced tumor burden (p=0.02) and prolonged survival was observed in mice bearing IP-10 positive tumors than mice bearing IP-10 negative tumors (p=0.03). We found that in mice bearing subcutaneous melanoma tumors, intratumoral injections of IFNγ triggered IP-10 production, as confirmed by protein analysis of tumor lysates. Mice that received intravenous injections of doxorubicin prior to IFNγ-injections and adoptive transfer of NK cells had a slower tumor progression than mice that received IFNγ alone prior to NK cell transfer. Conclusion: Secretion of IP-10 from melanoma tumors stimulates intratumoral infiltration of adoptively transferred NK cells, demonstrating the importance of IP-10/CXCR3 signaling in recruitment of NK cells to solid tumors. Intratumoral IFNγ-treatment of tumors triggers an increased local production of IP-10. Pretreatment of tumor cells with doxorubicin can offset INFγ-induced resistance to NK cell lysis in vitro and in vivo. Citation Format: Erik Wennerberg, Veronika Kremer, Andreas Lundqvist. IFN-gamma-inducible-protein-10 stimulates intratumoral infiltration of adoptively transferred human NK cells in a melanoma xenograft mouse model. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology: Multidisciplinary Science Driving Basic and Clinical Advances; Dec 2-5, 2012; Miami, FL. Philadelphia (PA): AACR; Cancer Res 2013;73(1 Suppl):Abstract nr A15.

Correlationship between chemokines and oxidative stress in chronic hepatitis B

The aim of this study is to investigate the possible associations of chemokines IP-10, Rantes and oxidative stress in chronic hepatits B (CHB). 70 CHB patients and 10 healthy controls were enrolled in the study. Enzyme-linked immunosorbent assay (ELISA) was used to detect the serum levels of IFN-gamma-inducible protein-10 (IP-10) and regulated on activation normal T-cell-expressed and secreted (Rantes) and oxidative stress parameters (glutathione, GSH; glutathione disulfide, GSSG). Correlationship were analyzed by Spearman's rank correlation. The levels of IP-10 and Rantes were higher in CHB patients than healthy controls, and strong positive associations were found between IP-10/Rantes and alanine aminotransferase (ALT). The levels of GSH and GSH/GSSG were lower in CHB patients than healthy controls, and GSH and GSH/GSSG were negatively correlated with ALT. The levels of IP-10 and Rantes were negatively correlated with GSH and GSH/GSSG respectively. Strong associations were found between chemokines and oxidative stress which participated in the pathogenesis of CHB.

Changes in the levels of cytokines, chemokines and malaria-specific antibodies in response to Plasmodium falciparum infection in children living in sympatry in Mali

BackgroundThe Fulani are known to be less susceptible to Plasmodium falciparum malaria as reflected by lower parasitaemia and fewer clinical symptoms than other sympatric ethnic groups. So far most studies in these groups have been performed on adults, which is why little is known about these responses in children. This study was designed to provide more information on this gap.MethodsCirculating inflammatory factors and antibody levels in children from the Fulani and Dogon ethnic groups were measured. The inflammatory cytokines; interleukin (IL)-1beta, IL-6, IL-8, IL-10, IL-12p70, tumor necrosis factor (TNF) and the chemokines; regulated on activation normal T cell expressed and secreted (RANTES), monokine-induced by IFN-gamma (MIG), monocyte chemotactic protein (MCP)-1 and IFN-gamma-inducible protein (IP)-10 were measured by cytometric bead arrays. The levels of interferon (IFN)-alpha, IFN-gamma and malaria-specific antibodies; immunoglobulin (Ig) G, IgM and IgG subclasses (IgG1-IgG4) were measured by ELISA.ResultsThe results revealed that the Fulani children had higher levels of all tested cytokines compared to the Dogon, in particular IFN-gamma, a cytokine known to be involved in parasite clearance. Out of all the tested chemokines, only MCP-1 was increased in the Fulani compared to the Dogon. When dividing the children into infected and uninfected individuals, infected Dogon had significantly lower levels of RANTES compared to their uninfected peers, and significantly higher levels of MIG and IP-10 as well as MCP-1, although the latter did not reach statistical significance. In contrast, such patterns were not seen in the infected Fulani children and their chemokine levels remained unchanged upon infection compared to uninfected counterparts. Furthermore, the Fulani also had higher titres of malaria-specific IgG and IgM as well as IgG1-3 subclasses compared to the Dogon.ConclusionsTaken together, this study demonstrates, in accordance with previous work, that Fulani children mount a stronger inflammatory and antibody response against P. falciparum parasites compared to the Dogon and that these differences are evident already at an early age. The inflammatory responses in the Fulani were not influenced by an active infection which could explain why less clinical symptoms are seen in this group.

IL28B polymorphisms, IP-10 and viral load predict virological response to therapy in chronic hepatitis C

Hepatitis C virus (HCV) is a major cause of chronic liver disease, cirrhosis and hepatocellular carcinoma and the identification of the predictors of response to antiviral therapy is an important clinical issue. To determine the independent contribution of factors including IL28B polymorphisms, IFN-gamma inducible protein-10 (IP-10) levels and the homeostasis model assessment of insulin resistance (HOMA-IR) score in predicting response to therapy in chronic hepatitis C (CHC). Multivariate analysis of factors predicting rapid (RVR) and sustained (SVR) virological response in 280 consecutive, treatment-naive CHC patients treated with peginterferon alpha and ribavirin in a prospective multicentre study. Independent predictors of RVR were HCV RNA <400 000 IU/mL (OR 11.37; 95% CI 3.03-42.6), rs12980275 AA (OR 7.09; 1.97-25.56) and IP-10 (OR 0.04; 0.003-0.56) in HCV genotype 1 patients and lower baseline γ-glutamyl-transferase levels (OR=0.02; 0.0009-0.31) in HCV genotype 3 patients. Independent predictors of SVR were rs12980275 AA (OR 9.68; 3.44-27.18), age <40 years (OR=4.79; 1.50-15.34) and HCV RNA <400 000 IU/mL (OR 2.74; 1.03-7.27) in HCV genotype 1 patients and rs12980275 AA (OR=6.26; 1.98-19.74) and age <40 years (OR 5.37; 1.54-18.75) in the 88 HCV genotype 1 patients without a RVR. RVR was by itself predictive of SVR in HCV genotype 1 patients (OR 33.0; 4.06-268.32) and the only independent predictor of SVR in HCV genotype 2 (OR 9.0, 1.72-46.99) or genotype 3 patients (OR 7.8, 1.43-42.67). In HCV genotype 1 patients, IL28B polymorphisms, HCV RNA load and IP-10 independently predict RVR. The combination of IL28B polymorphisms, HCV RNA level and age may yield more accurate pre-treatment prediction of SVR. HOMA-IR score is not associated with viral response.

282 EFFECT OF THE HBV PRES2 MUTANT ON T CELL RECOGNITION OF HEPATOCYTE TUMOR CELL LINES

respectively). An increased production of IFN-gamma was typical of both Vdelta1 and Vdelta2 in non responders CHC. No differences were found in IL-17 and TGF-beta production. Conclusion: A selectively enriched and activated peripheral Vdelta1 population characterises HCV patients with advanced, more active and long-lasting infection; its enhanced IFN-gamma production may explain, possibly via the overxpression of IFN-gammainducible protein-10, non-response to antiviral therapy.

Potential role and mechanism of IFN-gamma inducible protein-10 on receptor activator of nuclear factor kappa-B ligand (RANKL) expression in rheumatoid arthritis

IntroductionIFN-gamma inducible protein-10 (CXCL10), a member of the CXC chemokine family, and its receptor CXCR3 contribute to the recruitment of T cells from the blood stream into the inflamed joints and have a crucial role in perpetuating inflammation in rheumatoid arthritis (RA) synovial joints. Recently we showed the role of CXCL10 on receptor activator of nuclear factor kappa-B ligand (RANKL) expression in an animal model of RA and suggested the contribution to osteoclastogenesis. We tested the effects of CXCL10 on the expression of RANKL in RA synoviocytes and T cells, and we investigated which subunit of CXCR3 contributes to RANKL expression by CXCL10.MethodsSynoviocytes derived from RA patients were kept in culture for 24 hours in the presence or absence of TNF-α. CXCL10 expression was measured by reverse transcriptase polymerase chain reaction (RT-PCR) of cultured synoviocytes. Expression of RANKL was measured by RT-PCR and western blot in cultured synoviocytes with or without CXCL10 and also measured in Jurkat/Hut 78 T cells and CD4+ T cells in the presence of CXCL10 or dexamethasone. CXCL10 induced RANKL expression in Jurkat T cells was tested upon the pertussis toxin (PTX), an inhibitor of Gi subunit of G protein coupled receptor (GPCR). The synthetic siRNA for Gαi2 was used to knock down gene expression of respective proteins.ResultsCXCL10 expression in RA synoviocytes was increased by TNF-α. CXCL10 slightly increased RANKL expression in RA synoviocytes, but markedly increased RANKL expression in Jurkat/Hut 78 T cell or CD4+ T cell. CXCL10 augmented the expression of RANKL by 62.6%, and PTX inhibited both basal level of RANKL (from 37.4 ± 16.0 to 18.9 ± 13.0%) and CXCL10-induced RANKL expression in Jurkat T cells (from 100% to 48.6 ± 27.3%). Knock down of Gαi2 by siRNA transfection, which suppressed the basal level of RANKL (from 61.8 ± 17.9% to 31.1 ± 15.9%) and CXCL10-induced RANKL expression (from 100% to 53.1 ± 27.1%) in Jurkat T cells, is consistent with PTX, which inhibited RANKL expression.ConclusionsCXCL10 increased RANKL expression in CD4+ T cells and it was mediated by Gαi subunits of CXCR3. These results indicate that CXCL10 may have a potential role in osteoclastogenesis of RA synovial tissue and subsequent joint erosion.

Type 1 T-cell responses in chlamydial lung infections are associated with local MIP-1α response

Chemokines and their receptors are important mediators of leukocyte trafficking and recruitment and sometimes work as modulators of T-cell responses during infections and inflammation. Modulating the biological activity of chemokines has been found to influence the course of diseases. However, little is known about the role of chemokine responses during chlamydial lung infections. We therefore analyzed the dynamics of multiple chemokines, which are frequently associated with type 1 (Th1) T cell immune responses, and their receptors for their expression in the lungs during Chlamydia muridarum (Cm) infections. We also examined the relationship between chemokine responses and the development of Th1 responses as well as the clearance of infection. Our results showed that in parallel with the high levels of gamma interferon (IFN-gamma) and IL-12 production in the lungs and draining lymph nodes, and the expansion of IFN-gamma-producing CD4 and CD8+ T cells, the production of the cell-related chemokines RANTES, IFN-gamma-inducible protein-10 (IP-10) and macrophage inflammatory protein-1alpha (MIP-1alpha) and their receptor CCR1 was elevated in the lung tissues after infection. Interestingly, in a later phase of infection, the expression of RANTES and IP-10 remained elevated but the expression of MIP-1alpha and CCR1 decreased to a low level, which suggests a closer association with the pattern of Th1 cytokine responses in the process of infection. These results suggest a close association between the MIP-1alpha response and the Th1-type T-cell responses in chlamydial lung infections.

Possible Recruitment of Peripheral Blood CXCR3+CD27+CD19+B Cells to the Liver of Chronic Hepatitis C Patients

It has been suggested that hepatitis C virus (HCV) infects not only hepatocytes but also immune cells, including B cells. HCV infection of B cells is the likely cause of B-cell dysregulation disorders such as mixed cryoglobulinemia, rheumatoid factor production, and B-cell lymphoproliferative disorders that may evolve into non-Hodgkin's lymphoma. To clarify the effects of chronic HCV infection on B-cell dynamics, peripheral B cells from chronic hepatitis C patients (CHC) were characterized. We found that the frequency of CD27(+) B cells, that is memory phenotype, was significantly reduced in the peripheral blood of CHC. At the same time, the amount of IFN-gamma-inducible protein-10 (IP-10), a CXCR3 ligand, was markedly elevated in the plasma of CHC. Furthermore, the CD27(+) B-cell population was found to highly express CXCR3 in CHC, thus suggesting that the CD27(+) B-cell population was recruited from peripheral blood to the inflammatory site of the liver of CHC, where IP-10 is produced. Immunohistochemical analyses of intrahepatic lymphocytes indicated that CXCR3(+) B cells were infiltrated in the liver of CHC. Our results thus offer new insight into the role of memory B cells in the HCV pathogenesis.

Comparison of interferon gamma and interferon gamma-inducible protein-10 secretion in HIV–tuberculosis patients

Interferon gamma (IFNgamma)-based in-vitro assays have suboptimal sensitivity, especially in immunocompromised individuals, which emphasizes the need for alternative markers for tuberculosis (TB) diagnosis. We compared TB antigens-specific IFNgamma and IFNgamma-inducible protein-10 levels in culture of whole blood samples from HIV-TB patients. We report that IFNgamma-inducible protein-10 detects a greater number of HIV-TB cases than IFNgamma and suggest that IFNgamma-inducible protein-10 may be a better alternative marker for latent TB infection diagnosis among immunocompromised individuals.

IL-12-STAT4-IFN-γ axis is a key downstream pathway in the development of IL-13-mediated asthma phenotypes in a Th2 type asthma model

IL-4 and IL-13 are closely related cytokines that are produced by Th2 cells. However, IL-4 and IL-13 have different effects on the development of asthma phenotypes. Here, we evaluated downstream molecular mechanisms involved in the development of Th2 type asthma phenotypes. A murine model of Th2 asthma was used that involved intraperitoneal sensitization with an allergen (ovalbumin) plus alum and then challenge with ovalbumin alone. Asthma phenotypes, including airway-hyperresponsiveness (AHR), lung inflammation, and immunologic parameters were evaluated after allergen challenge in mice deficient in candidate genes. The present study showed that methacholine AHR and lung inflammation developed in allergen-challenged IL-4-deficient mice but not in allergen-challenged IL-13-deficient mice. In addition, the production of OVA-specific IgG2a and IFN-gamma-inducible protein (IP)-10 was also impaired in the absence of IL-13, but not of IL-4. Lung-targeted IFN-gamma over-expression in the airways enhanced methacholine AHR and non-eosinophilic inflammation; in addition, these asthma phenotypes were impaired in allergen-challenged IFN-gamma-deficient mice. Moreover, AHR, non-eosinophilic inflammation, and IFN-gamma expression were impaired in allergen-challenged IL-12Rbeta2- and STAT4-deficient mice; however, AHR and non-eosinophilic inflammation were not impaired in allergen-challenged IL-4Ralpha-deficient mice, and these phenomena were accompanied by the enhanced expression of IL-12 and IFN-gamma. The present data suggest that IL-13-mediated asthma phenotypes, such as AHR and non-eosinophilic inflammation, in the Th2 type asthma are dependent on the IL-12-STAT4-IFN-gamma axis, and that these asthma phenotypes are independent of IL-4Ralpha-mediated signaling.

Activation of invariant NKT cells confers protection against Chlamydia trachomatis-induced arthritis

The role of invariant NKT (iNKT) cells in reactive arthritis is unknown. We explored the functional role of NKT cells in reactive arthritis using an established murine model of Chlamydia trachomatis-induced arthritis (CtIA). CtIA in wild-type and CD1d knockout (KO) mice was induced by intra-articular injection of C. trachomatis. The effect of alpha-galactosylceramide (alpha-GalCer) activation of iNKT cells was investigated by intra-peritoneal administration of alpha-GalCer. Histopathological and phenotypic changes, chlamydial clearance and cytokine and chemokine production in synovial tissue of the knee joint were investigated after onset of the arthritis. The severity of CtIA was significantly increased in CD1d KO mice, which was associated with decrease in bactericidal cytokine IFN-gamma, regulatory cytokines IL-4 and IL-10 and increase in pro-inflammatory chemokines macrophage inflammatory protein-2 (MIP-2) and IFN-gamma-inducible protein-10 (IP-10). Local clearance of the pathogen from the joint was also decreased. Prior treatment of mice with alpha-GalCer, a potent activator of iNKT cells, significantly reduced the severity of CtIA in mice. The amelioration of CtIA was associated with decrease in chlamydial load and induction of cytokines IFN-gamma, IL-4 and IL-10 and significant suppression of MIP-2 and IP-10. Treatment of established CtIA with alpha-GalCer also demonstrated modulation of CtIA and decrease in chlamydial load. These results suggest that iNKT cells are protective against CtIA and alpha-GalCer-activated iNKT cells have an immunoregulatory role not only in preventing the induction of reactive arthritis but also in modulating established disease.