Role Of IFN-γ Research Articles

IFN-γ in turtle: Conservation in sequence and signalling and role in inhibiting iridovirus replication in Chinese soft-shelled turtle Pelodiscus sinensis

The IFN-γ gene was identified in a turtle, the Chinese soft-shelled turtle, Pelodiscus sinensis, with its genome consisting of 4 exons and 3 introns. The deduced amino acid sequence of this gene contains a signal peptide, an IFN-γ family signature motif 130IQRKAVNELFPT, an NLS motif 155KRKR and three potential N-glycosylation sites. As revealed by real-time quantitative PCR, the gene was constitutively expressed in all tested organs/tissues, with higher level observed in blood, intestine and thymus. An induced expression of IFN-γ at mRNA level was observed in peripheral blood leucocytes (PBLs) in response to in vitro stimulation of LPS and PolyI:C. The overexpression of IFN-γ in the Chinese soft-shelled turtle artery (STA) cell line resulted in the increase in the expression of transcriptional regulators, such as IRF1, IRF7 and STAT1, and antiviral genes, such as Mx, PKR, implying possibly the existence of a conserved signalling network and role for IFN-γ in the turtle. Furthermore, the infection of soft-shelled turtle iridovirus (STIV) in the cell line transfected with IFN-γ may cause the cell death as demonstrated with the elevated lactate dehydrogenase (LDH) level and cell mortality. However, the mechanism involved in the antiviral activity may require further investigation.

IFN-γ signaling in astrocytes and microglia has opposite roles in CNS autoimmunity (P5170)

Abstract IFN-γ, the hallmark cytokine of Th1 cells, plays an important role in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Thus far, the role of IFN-γ in EAE has been largely studied through its effects on immune cells, while much less is known about its effects on central nervous system (CNS) cells, especially in vivo. In this study we for the first time dissected the in vivo effects and mechanisms of IFN-γ signaling in astrocytes and microglia and found that IFN-γ signaling in these cell types has opposite effects in EAE pathogenesis. Silencing IFN-γ signaling in astrocytes ameliorated EAE, while in microglia it increased disease severity. Silencing IFN-γ signaling in astrocytes resulted in diminished expression of chemokines and fewer inflammatory cells infiltrating into the CNS, while blocking IFN-γ signaling in microglia increased disease severity through augmented activation and proliferation of microglia. Further, blocking IFN-γ signaling in astrocytes ameliorated both Th1- and Th17-mediated adoptive EAE, indicating an important role for IFN-γ signaling in astrocytes in autoimmune CNS inflammation. Thus, our study defines novel mechanisms of action of IFN-γ in EAE pathogenesis, and also highlights an opportunity for development of MS therapies directed at CNS cells.

The crucial roles of IFN-γ in the development of M3 muscarinic acetylcholine receptor induced Sjögren’s syndrome-like sialadenitis

The crucial roles of IFN-γ in the development of M3 muscarinic acetylcholine receptor induced Sjögren’s syndrome-like sialadenitis

Mycobacterium tuberculosis Exploits Human Interferon γ to Stimulate Macrophage Extracellular Trap Formation and Necrosis

Human neutrophils form extracellular traps during M. tuberculosis infection, but a similar phenomenon has not been reported in human macrophages. Here we demonstrate that M. tuberculosis induces release of extracellular traps from human macrophages. This process is regulated by elastase activity, previously shown to regulate formation of extracellular traps by neutrophils. Interestingly, formation of extracellular traps by macrophages during M. tuberculosis infection is inducible by interferon γ (IFN-γ). These traps are mainly produced by heavily infected macrophages. Accordingly, IFN-γ is found to stimulate M. tuberculosis aggregation in macrophages. Both IFN-γ–inducible events, extracellular trap formation and mycobacterial aggregation, require the ESX-1 secretion system. In addition, IFN-γ is found to enhance ESX-1–mediated macrophage necrosis. In the absence of ESX-1, IFN-γ does not restore any extracellular trap formation, mycobacterial aggregation, or macrophage necrosis. Thus, initial characterization of macrophage extracellular trap formation due to M. tuberculosis infection led to the uncovering of a novel role for IFN-γ in amplifying multiple effects of the mycobacterial ESX-1.

Pre‐existing central nervous system lesions negate cytokine requirements for regional experimental autoimmune encephalomyelitis development

In region-specific forms of experimental autoimmune encephalomyelitis (EAE), lesion initiation is regulated by T-cell-produced interferon-γ (IFN-γ) resulting in spinal cord disease in the presence of IFN-γ and cerebellar disease in the absence of IFN-γ. Although this role for IFN-γ in regional disease initiation is well defined, little is known about the consequences of previous tissue inflammation on subsequent regional disease, information vital to the development of therapeutics in established disease states. This study addressed the hypothesis that previous establishment of regional EAE would determine subsequent tissue localization of new T-cell invasion and associated symptoms regardless of the presence or absence of IFN-γ production. Serial transfer of optimal or suboptimal doses of encephalitogenic IFN-γ-sufficient or -deficient T-cell lines was used to examine the development of new clinical responses associated with the spinal cord and cerebellum at various times after EAE initiation. Previous inflammation within either cerebellum or spinal cord allowed subsequent T-cell driven inflammation within that tissue regardless of IFN-γ presence. Further, T-cell IFN-γ production after initial lesion formation exacerbated disease within the cerebellum, suggesting that IFN-γ plays different roles at different stages of cerebellar disease. For the spinal cord, IFN-γ-deficient cells (that are ordinarily cerebellum disease initiators) were capable of driving new spinal-cord-associated clinical symptoms more than 60 days after the initial acute EAE resolution. These data suggest that previous inflammation modulates the molecular requirements for new neuroinflammation development.

Celiac Disease and Ischemic Heart Disease: What is the Link?

In a recent publication by De Marchi et al. [1], coeliac disease (CD) in young adults was linked to a potential increase in risk for early atherosclerosis [1]. Of note, it has been previously reported a positive association between CD and ischemic heart disease (IHD) [2,3]. Concordantly, it has been found that subclinical cardiac involvement and cardiovascular disease risk factors are quite frequent in celiac children when compared to healthy subjects [4,5]. Until today, it is not well-defined whether a cause-and-effect relationship can be inferred from the association between CD and IHD or if these conditions occur as consequences of a common underlying cause. CD patients may suffer primarily from gastrointestinal symptoms, even if the disease may be related to lots of extraintestinal disorders [6,7]. CD has been described as a chronic systemic immune-mediated condition triggered by dietary gluten in genetically susceptible individuals [4]. Gluten-sensitive enteropathy is characterized by villous atrophy, various degrees of crypt cell hyperplasia and increased numbers of intraepithelial lymphocytes of the proximal small intestine [6-9]. It has been assessed that the cytokine expression pattern in response to gluten is strongly dominated by Interferon-γ (IFN-γ) and that celiac patients show an increased expression of IFN-γ and a high number of TCD4+IFN-γ-producing cells [7]. IFN-γ has been illustrated as a key determinant in gut permeability as well as in inflammation in CD [8,9]. It has been found that IFN-γ secreted by gluten-activated celiac patient T cells, represents the primary effector of increased gluten peptide translocation during active disease [9]. Toxic gluten peptides have been reported to elicit an important immune response in the celiac intestine after regiospecific deamidation by an endogenous extracellular enzyme, transglutaminase 2 (TG2) [10]. It has been recognized that IFN-γ is the most potent inducer of TG2 [8]. It has been detected that IFN-γ mediated activation of TG2 requires phospatidylinositol-3-kinases (PI3Ks) activity [10]. It is now accepted that chronic inflammation is considered as a major pathogenic factor in atherosclerosis and cardiovascular accidents [11]. Atherosclerosis has been linked to heart attack and ischemic stroke representing its major clinical consequences [11-13]. The atherosclerotic vascular remodelling and pathophysiology involve multiple cell types and a wide range of mediators and cascades [12]. Inflammatory factors, such as cytokines and adhesion molecules, have been connected with the onset and propagation of the atherosclerotic lesion [11,12]. Among the cytokines, IFN-γ has been shown to be a critical player in atherogenesis and in the development and progression of cardiovascular disease [12,13]. IFN-γ has been found to be expressed at high levels in atherosclerotic lesions [12,13]. Interestingly, it has been provided evidence that IFN-γ regulates the function and properties of all the cell types in the vessel [12]. Moreover, it has been suggested that serum concentrations of IFN-γ correlate with severe left ventricular dysfunction in patients affected by acute myocardial infarction [14]. The basic pathophysiological mechanisms underlying cardiovascular events are mediated via a number of factors and signaling pathways including PI3Ks in a variety of a different cell types, such as endothelial cells, smooth muscle cells, platelets, monocytes and cardiomyocites [12]. It has been shown that PI3K-related signaling pathways are crucial in the pathogenesis of cardiovascular diseases [12]. PI3Ks have also been revealed to dominate the inflammatory aspects of atherosclerosis [12]. With respect to the above, we advance the hypothesis that patients suffering from CD may be at increased risk of IHD. We suppose that CD and IHD may share a common underlying link. The autoimmune etiology of CD and the potential role of inflammation in the development of atherosclerosis and IHD, point to inflammation and the immune system as target areas for research. We postulate that aberrant expression of IFN-γ may be responsible for susceptibility to IHD in CD patients through upregulation of PI3K-related signalling pathways. For that reason, celiac patients should be screened for other factors that also increase the chance that existing IHD will worsen such as high blood pressure, high cholesterol, obesity, diabetes, hyperhomocysteinemia, smoking and physical inactivity both at the time of diagnosis and during follow-up considering the possible coexistence of these conditions. Identification of the mechanisms that trigger early development of atherosclerosis in CD is important for development of interventions to prevent and treat CVD in this population given that that there is increasing incidence of CD in the world. Large prospective trials are needed to verify the possible role of IFN-γ in the positive association between latent CD and IHD. Strict adherence to a gluten free is currently the only effective management of CD. However, cardiovascular disease screening and a dietary counseling targeting cardiovascular disease prevention may contribute significantly to improve or go away cardiac complications. PI3K inhibitors may represent a potential attractive therapeutic option for immunomodulatory intervention strategy to halt or even prevent IHD in CD patients slowing down the adverse effects of IFN-γ.

Roles of IFN-γ and γδ T Cells in Protective Immunity Against Blood-Stage Malaria

Malaria is caused by infection with Plasmodium parasites. Various studies with knockout mice have indicated that IFN-γ plays essential roles in protective immunity against blood-stage Plasmodium infection. However, after Plasmodium infection, increased IFN-γ production by various types of cells is involved not only in protective immunity, but also in immunopathology. Recent reports have shown that IFN-γ acts as a pro-inflammatory cytokine to induce not only the activation of macrophages, but also the generation of uncommon myelolymphoid progenitor cells after Plasmodium infection. However, the effects of IFN-γ on hematopoietic stem cells and progenitor cells are unclear. Therefore, the regulation of hematopoiesis by IFN-γ during Plasmodium infection remains to be clarified. Although there are conflicting reports concerning the significance of γδ T cells in protective immunity against Plasmodium infection, γδ T cells may respond to infection and produce IFN-γ as innate immune cells in the early phase of blood-stage malaria. Our recent studies have shown that γδ T cells express CD40 ligand and produce IFN-γ after Plasmodium infection, resulting in the enhancement of dendritic cell activation as part of the immune response to eliminate Plasmodium parasites. These data suggest that the function of γδ T cells is similar to that of NK cells. Although several reports suggest that γδ T cells have the potential to act as memory cells for various infections, it remains to be determined whether memory γδ T cells are generated by Plasmodium infection and whether memory γδ T cells can contribute to the host defense against re-infection with Plasmodium. Here, we summarize and discuss the effects of IFN-γ and the various functions of γδ T cells in blood-stage Plasmodium infection.

Interferon-γ-induced activation of Signal Transducer and Activator of Transcription 1 (STAT1) up-regulates the tumor suppressing microRNA-29 family in melanoma cells

BackgroundThe type-II-cytokine IFN-γ is a pivotal player in innate immune responses but also assumes functions in controlling tumor cell growth by orchestrating cellular responses against neoplastic cells. The role of IFN-γ in melanoma is not fully understood: it is a well-known growth inhibitor of melanoma cells in vitro. On the other hand, IFN-γ may also facilitate melanoma progression. While interferon-regulated genes encoding proteins have been intensively studied since decades, the contribution of miRNAs to effects mediated by interferons is an emerging area of research.We recently described a distinct and dynamic regulation of a whole panel of microRNAs (miRNAs) after IFN-γ-stimulation. The aim of this study was to analyze the transcriptional regulation of miR-29 family members in detail, identify potential interesting target genes and thus further elucidate a potential signaling pathway IFN-γ → Jak→ P-STAT1 → miR-29 → miR-29 target genes and its implication for melanoma growth.ResultsHere we show that IFN-γ induces STAT1-dependently a profound up-regulation of the miR-29 primary cluster pri-29a~b-1 in melanoma cell lines. Furthermore, expression levels of pri-29a~b-1 and mature miR-29a and miR-29b were elevated while the pri-29b-2~c cluster was almost undetectable. We observed an inverse correlation between miR-29a/b expression and the proliferation rate of various melanoma cell lines. This finding could be corroborated in cells transfected with either miR-29 mimics or inhibitors. The IFN-γ-induced G1-arrest of melanoma cells involves down-regulation of CDK6, which we proved to be a direct target of miR-29 in these cells. Compared to nevi and normal skin, and metastatic melanoma samples, miR-29a and miR-29b levels were found strikingly elevated in certain patient samples derived from primary melanoma.ConclusionsOur findings reveal that the miR-29a/b1 cluster is to be included in the group of IFN- and STAT-regulated genes. The up-regulated miR-29 family members may act as effectors of cytokine signalling in melanoma and other cancer cells as well as in the immune system.

Role of IFN-γ and Metalloproteinases ADAM10 and ADAM17/TACE in Soluble CD30 Release During the Alloimmune Response

Role of IFN-γ and Metalloproteinases ADAM10 and ADAM17/TACE in Soluble CD30 Release During the Alloimmune Response

Differential Effects of IL-12 on Tregs and Non-Treg T Cells: Roles of IFN-γ, IL-2 and IL-2R

Complex interactions between effector T cells and Foxp3+ regulatory T cells (Treg) contribute to clinical outcomes in cancer, and autoimmune and infectious diseases. Previous work showed that IL-12 reversed Treg-mediated suppression of CD4+Foxp3− T cell (Tconv) proliferation. We and others have also shown that Tregs express T-bet and IFN-γ at sites of Th1 inflammation and that IL-12 induces IFN-γ production by Tregs in vitro. To investigate whether loss of immunosuppression occurs when IFN-γ is expressed by Tregs we treated mouse lymphocyte cultures with IL-12. IFN-γ expression did not decrease the ability of Tregs to suppress Tconv proliferation. Rather, IL-12 treatment decreased Treg frequency and Foxp3 levels in Tregs. We further showed that IL-12 increased IL-2R expression on Tconv and CD8 T cells, diminished its expression on Tregs and decreased IL-2 production by Tconv and CD8 T cells. Together, these IL-12 mediated changes favored the outgrowth of non-Tregs. Additionally, we showed that treatment with a second cytokine, IL-27, decreased IL-2 expression without augmenting Tconv and CD8 T cell proliferation. Notably, IL-27 only slightly modified levels of IL-2R on non-Treg T cells. Together, these results show that IL-12 has multiple effects that modify the balance between Tregs and non-Tregs and support an important role for relative levels of IL-2R but not for IFN-γ expression in IL-12-mediated reversal of Treg immunosuppression.

IFN-γ and TNF-α Synergize to Inhibit CTGF Expression in Human Lung Endothelial Cells

Connective tissue growth factor (CTGF/CCN2) is an angiogenetic and profibrotic factor, acting downstream of TGF-β, involved in both airway- and vascular remodeling. While the T-helper 1 (Th1) cytokine interferon-gamma (IFN-γ) is well characterized as immune-modulatory and anti-fibrotic cytokine, the role of IFN-γ in lung endothelial cells (LEC) is less defined. Tumour necrosis factor alpha (TNF-α) is another mediator that drives vascular remodeling in inflammation by influencing CTGF expression. In the present study we investigated the influence of IFN-γ and TNF-α on CTGF expression in human LEC (HPMEC-ST1.6R) and the effect of CTGF knock down on human LEC. IFN-γ and TNF-α down-regulated CTGF in human LEC at the promoter-, transcriptional- and translational-level in a dose- and time-dependent manner. The inhibitory effect of IFN-γ on CTGF-expression could be almost completely compensated by the Jak inhibitor AG-490, showing the involvement of the Jak-Stat signaling pathway. Besides the inhibitory effect of IFN-γ and TNF-α alone on CTGF expression and LEC proliferation, these cytokines had an additive inhibitory effect on proliferation as well as on CTGF expression when administered together. To study the functional role of CTGF in LEC, endogenous CTGF expression was down-regulated by a lentiviral system. CTGF silencing in LEC by transduction of CTGF shRNA reduced cell proliferation, but did not influence the anti-proliferative effect of IFN-γ and TNF-α. In conclusion, our data demonstrated that CTGF was negatively regulated by IFN-γ in LEC in a Jak/Stat signaling pathway-dependent manner. In addition, an additive effect of IFN-γ and TNF-α on inhibition of CTGF expression and cell proliferation could be found. The inverse correlation between IFN-γ and CTGF expression in LEC could mean that screwing the Th2 response to a Th1 response with an additional IFN-γ production might be beneficial to avoid airway remodeling in asthma.

PD-1, IL-10, IFN-γ and IL-12 form a network to regulate HIV-1-specific CD4 T Cell and antigen-presenting cell function

Background PD-1 and IL-10 blockade can restore antigen-specific T cell functions in chronic infections and cancer. However, not all subjects respond to inhibition of either pathway, the potential differences in functions restored by these interventions are unknown, and mechanistic interactions between these pathways are poorly understood. Methods We investigated 45 subjects with HIV-1 infection with different disease status. We used CFSE assays to measure proliferation of HIV-1-specific CD4 T cells and Luminex arrays to analyze IFN-g(Th1), IL-2(Th0), IL-13(Th2) and IL-12 secretion in supernatants of CD8-depleted PBMC stimulated for 48h with Gag peptide pools in the presence of isotype control antibody, anti-PD-L1 and/or anti-IL-10Ra, anti-IFN-g or anti-IL-12. We used flow cytometry to evaluate the role of IFN-g in regulating PD-L1, HLA-DR, HLA-ABC and CD86 expression by monocytes.

Is interferon-gamma the right marker for bacille Calmette–Guérin-induced immune protection? The missing link in our understanding of tuberculosis immunology

Bacille Calmette-Guérin (BCG), developed a century ago, is the only licensed tuberculosis (TB) vaccine in use to date. The protective efficacy of BCG against TB varies with no apparent protection in some population, and mechanisms of its immune protection is poorly known, and yet BCG is the most widely used vaccine, with more than 4 billion BCG-vaccinated children globally. BCG is probably the only licensed vaccine currently in use believed to mediate immune protection through the production of interferon (IFN)-γ by CD4 T cells, which in turn activates macrophages to kill Mycobacterium tuberculosis (Mtb). Currently, a number of new TB candidate vaccines are in different phases of clinical trial. The majority of these new vaccines are either recombinant forms of BCG or prime boosters of BCG (rBCG) and their immunogenicity is tested using BCG as a benchmark by measuring specific IFN-γ produced by CD4(+) T cells as a protective immune marker. However, some recent studies that examined mechanisms of immune protection of BCG in animals and humans have reported a lack of correlation between IFN-γ production by CD4 cells and BCG-induced immune protection. These studies point to the fact that there is a missing link in our understanding of TB immunology. Conversely, there is emerging evidence that other T cell subsets (gammadelta, γδ), CD8(+) T cells and natural killer (NK) cells may play a vital role in immune protection against Mtb infection and BCG-induced immune protection. γδ T cells and NK cells, which were considered to be part of the innate immunity in the past, have been shown to develop immunological memory upon re-encounter with the same pathogen. In this paper, the controversy over the role of IFN-γ as a marker for protective immunity against TB, and emerging data on the role of γδ T cells, CD8(+) and NK cells in TB immunology, will be presented.

Effect of interferon-γ on the fusion of mononuclear osteoclasts into bone-resorbing osteoclasts

Osteoclasts are multinucleated cells that are formed by the fusion of pre-fusion osteoclasts (pOCs). The fusion of pOCs is known to be important for osteoclastic bone resorption. Here, we examined the effect of IFN-γ on the fusion of pOCs. IFN-γ greatly increased the fusion of pOCs in a dose-dependent manner. Furthermore, IFN-γ induced pOC fusion even in hydroxyapatite-coated plates used as a substitute for bone. The resorption area of pOCs stimulated with IFN-γ was significantly higher than that of the control cells. IFN-γ induced the expression of dendritic cell-specific transmembrane protein (DC-STAMP), which is responsible for the fusion of pOCs. IFN-γ enhanced DC-STAMP expression in a dose-dependent manner. The mRNA expression of c-Fos and nuclear factor of activated T cells (NFAT) c1 was enhanced in the pOCs treated with IFN-γ. Taken together, these results provide a new insight into the novel role of IFN-γ on the fusion of pOCs.

IRF7-dependent IFNβ production in response to RANK facilitates medullary thymic epithelial cell development. (60.3)

Abstract The signal transducer and activator of transcription 1 (STAT1) is an essential part of signaling cascades induced by type I and II interferons. Deficiency of STAT1 results in heightened susceptibility to infections and autoimmunity in mouse and humans. While the role of IFNγ in T cell development is well known, the role of type I interferons in thymic development has largely remained unexplored. Here we show that STAT1 and IFNAR-deficient mice harbor a defect in medullary compartment characterized by a significant reduction in self-antigen presenting, AIRE expressing medullary thymic epithelial cells. Using a novel reporter mouse we demonstrate that constitutive IFNAR signaling is taking place in the thymic medulla in the absence of any infection or inflammatory signals. In addition, we found that RANK stimulation in thymic stromal cells results in the upregulation of IFNβ which in turn is inhibits RANK signaling thereby facilitating AIRE expression. Finally, we show that IRF7 is required for the induction of IFNβ by RANKL, and that IRF7-, but not IRF3-deficient mice display a defect in thymic architecture and medullary thymic epithelial cell differentiation similar to that observed in IFNAR- or STAT1-deficient animals. These results illustrate that a spatially and temporally coordinated crosstalk between the RANKL/RANK signaling pathway and the IRF7/IFNβ/IFNAR/STAT1 axis is essential for the differentiation of AIRE-expressing medullary thymic epithelial cells.

Crude Extracts of Caenorhabditis elegans Suppress Airway Inflammation in a Murine Model of Allergic Asthma

Epidemiological studies suggest an inverse relationship between helminth infections and allergic disease, and several helminth-derived products have been shown to suppress allergic responses in animals. This study was undertaken to evaluate the effect of a crude extract of Caenorhabditis elegans on allergic airway inflammation in a murine model of asthma. Allergic airway inflammation was induced in BALB/c mice by sensitization with ovalbumin. The effect of the C. elegans crude extract on the development of asthma and on established asthma was evaluated by analyzing airway hyperresponsiveness, serum antibody titers, lung histology and cell counts and cytokine levels in the bronchoalveolar lavage fluid. The role of IFN-γ in the suppression of asthma by the C. elegans crude extract was investigated in IFN-γ knockout and wild-type mice. When mice were sensitized with ovalbumin together with the crude extract of C. elegans, cellular infiltration into the lung was dramatically reduced in comparison with the ovalbumin-treated group. Treatment of mice with the C. elegans crude extract significantly decreased methacholine-induced airway hyperresponsiveness and the total cell counts and levels of IL-4, IL-5 and IL-13 in the bronchoalveolar lavage fluid but increased the levels of IFN-γ and IL-12. Sensitization with the C. elegans crude extract significantly diminished the IgE and IgG1 responses but provoked elevated IgG2a levels. However, the suppressive effect of the C. elegans crude extract was abolished in IFN-γ knockout mice, and the Th2 responses in these mice were as strong as those in wild-type mice sensitized with ovalbumin. The crude extract of C. elegans also suppressed the airway inflammation associated with established asthma. This study provides new insights into immune modulation by the C. elegans crude extract, which suppressed airway inflammation in mice not only during the development of asthma but also after its establishment by skewing allergen-induced Th2 responses to Th1 responses.

Expression of IFN-γ, IL-1α, NGF-β and TNF-α during the development of cerebellar cortex of Western Anhui white goose

The strep avidin-biotin-peroxidase complex (SABC) immunohistochemical methods were applied to investigate the localization and semi-quantitative distribution of IFN-γ, IL-1α, NGF-β and TNF-α-immunoreactive cells in the cerebellar cortex of Western Anhui white goose at embryonic day 13, 19, 24, 28 (E13, E19, E24, E28) and postnatal day 7, 15 (P7, P15). The possible roles of IFN-γ,IL-1α,NGF-β and TNF-α in the development of cerebellar cortex were discussed. The results indicated that in the external granular layer, there were IFN-γ and TNF-α positive cells at E13, E19, E24, E28, P7, IL-1α positive cells at E13, E19, E24, E28 and NGF-β positive cells at E13, E19 , E24. The expression levels of these four cytokines all reached peaks at E19 of the six tested periods in this study. In the Purkinje cell layer, there were IFN-γ, IL-1α and TNF-α positive cells at E13, E19, E24, E28, P7, P15 and NGF-β positive cells at E13, E19, E24, E28, P7. In the internal granular layer, there were IFN-γ positive cells at E13, E19, E24, E28, P7, P15, IL-1α and TNF-α positive cells at E13, E19, E24, E28, P7 and NGF-β positive cells at E13, E19, E24, E28. These results showed that E19 might be the "critical stage"in the cerebellar cortex development of Western Anhui white goose. IFN-γ, IL-1α and TNF-α might be synthesized by cerebellar cortex itself, and NGF-β could be transported from regions which project to Purkinje cells. IFN-γ may interfer the transfer of granular cells, and NGF-β may have neurotrophic functions that are beneficial to the growth and development of Purkinje cells.

Interferon gamma upregulates frataxin and corrects the functional deficits in a Friedreich ataxia model

Friedreich's ataxia (FRDA) is the most common hereditary ataxia, affecting ∼3 in 100 000 individuals in Caucasian populations. It is caused by intronic GAA repeat expansions that hinder the expression of the FXN gene, resulting in defective levels of the mitochondrial protein frataxin. Sensory neurons in dorsal root ganglia (DRG) are particularly damaged by frataxin deficiency. There is no specific therapy for FRDA. Here, we show that frataxin levels can be upregulated by interferon gamma (IFNγ) in a variety of cell types, including primary cells derived from FRDA patients. IFNγ appears to act largely through a transcriptional mechanism on the FXN gene. Importantly, in vivo treatment with IFNγ increases frataxin expression in DRG neurons, prevents their pathological changes and ameliorates the sensorimotor performance in FRDA mice. These results disclose new roles for IFNγ in cellular metabolism and have direct implications for the treatment of FRDA.

Effects of Gametophytes of Ecklonia Kurome on the Levels of Glucose and Triacylglycerol in db/db, Prediabetic C57BL/6J and IFN-γ KO Mice

We have studied edible algae that have the potential to down-regulate blood glucose. In Japan, Ecklonia species have been believed to improve the circulation of blood. In this study, we used leptin receptor deficient type 2 diabetes model mice (db/db) and prediabetic C57BL/6J mice. We also focused on the role of IFN-γ in the control of blood levels of triacylglycerol and glucose, because it is reportedly engaged in the regulation of energy consumption together with leptin. We report that gametophytes of Ecklonia kurome down-regulate the blood level of glucose and serum level of triacylglycerol in db/db. We also report that gametophytes of Ecklonia kurome down-regulate the level of glucose but not the level of triacylglycerol in prediabetic C57BL/6J mice induced by a high fat diet. They increased the level of triacylglycerol compared to that of control group in C57BL/6J, but not in IFN-γ KO mice. Gametophytes of Ecklonia kurome were administered orally to prediabetic C57BL/6J and IFN-γ KO mice and oral glucose tolerance tests were performed to evaluate the effects of algae. During the administration of the normal diet, we found a higher level of blood glucose in a glucose tolerance test of IFN-γ KO mice compared with that of C57BL/6J. Although a high fat diet induced a higher level of blood glucose compared with a normal diet group in a glucose tolerance test of C57BL/6J mice, this effect of high fat diet was not observed clearly at first but appeared three hours after glucose administration in IFN-γ KO mice. Gametophytes of Ecklonia kurome down-regulated the level of blood glucose in both C57BL/6J and IFN-γ KO mice, when administered a normal diet after making them prediabetic. These results suggest that Ecklonia kurome are effective to down-regulate the blood glucose and IFN-γ is involved in the regulation of blood glucose and triacylglycerol.

58 Long-term IFN-γ Treatment Alters Allergic Inflammation-Associated Gene Expression in Conjunctival Fibroblasts

BackgroundInterferon-γ (IFN-γ) is a T helper type 1 (Th1) cytokine which has antiviral, anti-proliferative, and immunomodulatory properties. Despite the presence of IFN-γ in the conjunctiva or tear fluid of patients with severe allergic conjunctivitis, the role of IFN-γ in allergic conjunctivitis is controversial and enigmatic. In this study, we assess the effect of long-term treatment of IFN-γ on human conjuctival fibroblasts.MethodsPrimary cultured fibroblasts derived from human conjunctiva specimens were established. Cultured fibroblasts were incubated with or without IFN-γ (10 ng/mL) for up to 14 days. After IFN-γ treatment, cells were washed out and were re-stimulated with combinations of IL-4 (10 ng/mL) and TNFα (10 ng/mL) for 6 hours. Then, total mRNAs were isolated and mRNA expression levels were measured using a microarray and real time-PCR.ResultsIn IFN-γ treated fibroblasts in short-term (6 hours), we confirmed the increased expression levels of well-known interferon induced genes, such as MHC class II, IRF1 and CXCL10. Increased expression of CCL11 stimulated by IL-4 + TNFα was suppressed by short-term IFN-γ treatment as described previously. In long-term (14 days) IFN-γ treated cells, the expression of CCL11 and several proinflammatory chemokines, which were associated with Th2 cell and eosinophil migration, was slightly but significantly increased without any other stimulations. Interestingly, IL-4 + TNFα stimulation greatly enhanced the expression levels of these chemokines, suggesting that long-term IFN-γ treatment alters the competency of gene expression potential on these gene loci in contrast to the situation for short term treatment. Time-course analysis of IFN-γ treatment revealed that the treatment of IFN-γ up to 24 hours suppressed the IL-4 + TNFα-induced CCL11 expression, whereas the CCL11 expression was enhanced 3 days after the treatment.ConclusionsThese results uncovered previously unsuspected contribution of IFN-γ to the fibroblasts in allergic inflammatory milieu in terms of the change in production of certain chemokines. In other words, the antagonistic function of IFN-γ to Th2 cells at the early phase may represent only a small part. The intracellular signaling and IFN-γ-dependent secondary events are needed to be explored to explain the long-term effect or the late phase phenomenon after IFN-γ administration.