It was widely known that retinoic acid inducible gene I (RIG-I) functions as a cytosolic pattern recognition receptor that initiates innate antiviral immunity by detecting exogenous viral RNAs. However, recent studies showed that RIG-I participates in other various cellular activities by sensing endogenous RNAs under different circumstances. For example, RIG-I facilitates the therapy resistance and expansion of breast cancer cells and promotes T cell-independent B cell activation through interferon signaling activation by recognizing non-coding RNAs and endogenous retroviruses in certain situations. While in hepatocellular carcinoma and acute myeloid leukemia, RIG-I acts as a tumor suppressor through either augmenting STAT1 activation by competitively binding STAT1 against its negative regulator SHP1 or inhibiting AKT-mTOR signaling pathway by directly interacting with Src respectively. These new findings suggest that RIG-I plays more diverse roles in various cellular life activities, such as cell proliferation and differentiation, than previously known. Taken together, the function of RIG-I exceeds far beyond that of a pattern recognition receptor.
Animals ; DEAD Box Protein 58 ; genetics ; metabolism ; Mice ; RNA, Viral ; genetics ; metabolism ; STAT1 Transcription Factor ; genetics ; metabolism ; Signal Transduction ; genetics ; physiology

Interferon response is the first line of host defense against virus infection. Recent years have witnessed tremendous progress in understanding of fish innate response to virus infection, especially in fish interferon antiviral response. A line of fish genes involved in interferon antiviral response have been identified and functional studies further reveal that fish possess an IFN antiviral system similar to mammals. However, fish virus-induced interferon genes contain introns similar to mammalian type III interferon genes although they encode proteins similar to type I interferons, which makes it hard to understand the evolution of vertebrate interferon genes directly resulting in a debate on nomenclature of fish interferon genes. Actually, fish display some unique mechanisms underlying interferon antiviral response. This review documents the recent progress on fish interferon response and its molecular mechanism.
Animals ; Fish Diseases ; immunology ; virology ; Fish Proteins ; genetics ; metabolism ; Fishes ; immunology ; virology ; Gene Expression Regulation ; Interferons ; genetics ; immunology ; STAT1 Transcription Factor ; metabolism ; Virus Diseases ; immunology ; veterinary

BACKGROUNDAlthough the onset of anemia during infectious disease is commonly correlated with production of inflammatory cytokines, the mechanisms by which cytokines induce anemia are poorly defined. This study focused on the mechanism research.

METHODSDifferent types of mice were infected perorally with Toxoplasma gondii strain ME49. At the indicated times, samples from each mouse were harvested, processed, and analyzed individually. Blood samples were analyzed using a Coulter Counter and red blood cell (RBC) survival was measured by biotinylation. Levels of tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), and inducible protein 10 (IP-10) mRNA in liver tissue were measured by real-time polymerase chain reaction.

RESULTST. gondii-infected mice exhibited anemia due to a decrease in both erythropoiesis and survival time of RBC in the circulation (P < 0.02). In addition, infection-stimulated anemia was associated with fecal occult, supporting previous literature that hemorrhage is a consequence of T. gondii infection in mice. Infection-induced anemia was abolished in interferon gamma (IFNγ) and IFNγ receptor deficient mice (P < 0.05) but was still evident in mice lacking TNF-α, iNOS, phagocyte NADPH oxidase or IP-10 (P < 0.02). Neither signal transducer and activator of transcription 1 (STAT1) deficient mice nor 129S6 controls exhibited decreased erythropoiesis, but rather suffered from an anemia resulting solely from increased loss of circulating RBC.

CONCLUSIONSInfection-stimulated decrease in erythropoiesis and losses of RBC have distinct mechanistic bases. These results show that during T. gondii infection, IFNγ is responsible for an anemia that results from both a decrease in erythropoiesis and a STAT1 independent loss of circulating RBC.

Anemia ; genetics ; metabolism ; Animals ; Erythrocytes ; pathology ; Interferon-gamma ; metabolism ; Male ; Mice ; Mice, Knockout ; Nitric Oxide Synthase Type II ; genetics ; metabolism ; Receptors, Interferon ; genetics ; metabolism ; STAT1 Transcription Factor ; genetics ; metabolism ; Toxoplasma ; pathogenicity ; Tumor Necrosis Factor-alpha ; genetics ; metabolism

To study the effect of HCV core protein on the interferon-induced antiviral genes expression and its mechanisms. Methods HepG2 cells were transiently transfected with HCV core protein expression plasmid and the blank plasmid respectively. RT-PCR was used to analyze the effect of HCV core protein on PKR and 2'-5'OAS expression. The effect of HCV core protein on ISRE-medicated gene expression was detected by luciferase activity assay. Western-blot assay was performed to observe the change of mRNA and protein levels of SOCS3, STAT1 and p-STAT1 following HCV core expression. In the presence of HCV core protein, the transcription of PKR and 2'-5' OAS are down-regulated. ISRE-medicated reporter gene expression and STAT1 phosphorylation were inhibited. The transcription and expression of SOCS3 were induced compared with blank plasmid-transfected group. In HepG2 cells, HCV core protein can down-regulate the expression of some interferon-induced antiviral genes, which involves the induction of SOCS3 and the inhibition of STAT1 phosphorylation.
2',5'-Oligoadenylate Synthetase ; genetics ; metabolism ; Carcinoma, Hepatocellular ; pathology ; Down-Regulation ; Hepacivirus ; genetics ; metabolism ; Humans ; Interferon-Stimulated Gene Factor 3 ; genetics ; metabolism ; Interferon-alpha ; genetics ; immunology ; Liver Neoplasms ; pathology ; Protein Kinases ; genetics ; metabolism ; STAT1 Transcription Factor ; genetics ; metabolism ; STAT2 Transcription Factor ; genetics ; metabolism ; Transcription, Genetic ; Transfection ; Tumor Cells, Cultured ; Viral Core Proteins ; genetics ; metabolism ; physiology

BACKGROUNDHow the transcriptional factors regulated the innate and adaptive immune system in pregnancy and pre-eclampsia are less understood. Nevertheless, what the plasma work in the development of this disease was not sure. The present study was design to evaluate what the transcriptional factors change in innate and adaptive immune system and what the plasma do in this filed.

METHODSPeripheral blood mononuclear cells (PBMC) from non-pregnant women (n = 18), women with clinically normal pregnancies (n = 23) and women with pre-eclampsia (n = 20) were separated from peripheral blood to isolate monocytes and T cells. The purity of monocytes and T cells were analysed by flow cytometry. Monocytes and T cells were stimulated in either lipopolysaccharides (LPS) or phorbol-myristate-acetate (PMA), respectively. Transcription Factor Arrays were used to screen the transcription factors of interest in comparing of different groups. PBMC were isolated from another 8 non-pregnant samples were co-incubated with different groups of plasma. Polymerase chain reaction (PCR) was performed using whole cell extractions of the samples.

RESULTSNuclear factor of activated T-cells-1 (NFAT-1), signal transducers and activators of transcription-1 (STAT-1) and activator protein-1 (AP-1) are up-regulated in monocytes in pregnancy and more so in pre-eclampsia. On the the contrary, NFAT-1, STAT-1 and AP-1 are down-regulated in T cells in pregnancy and more so in pre-eclampsia. A reduction was observed in interferon (IFN)-γ, interleukin (IL)-12 and IL-4 expression in T cells incubated with pre-eclamptic plasma. An elevation was observed in tumor necrosis factor (TNF)-α, IL-1 and IL-12 expression in monocytes incubated with pre-eclamptic plasma.

CONCLUSIONSInnate immunity is over activated and adaptive immunity is over suppressed in the development of pre-eclampsia. NFAT-1, STAT-1 and AP-1 might be the central transcription factors in the pathogenesis of pre-eclampsia. They induced some changes in plasma and "educate" the monocytes and T cells for relevant cytokine production. Successful completion of this study will enhance our understanding of pre-eclampsia and will discover new knowledge beyond pregnancy. The work will inform future therapies for the treatment of a wide range of condition such as transplantation immunology and a wide range of immune and inflammatory conditions.

Adult ; Female ; Humans ; Immunity, Innate ; physiology ; Interferon-gamma ; metabolism ; Interleukin-12 ; metabolism ; Interleukin-4 ; metabolism ; Leukocytes, Mononuclear ; metabolism ; Male ; NFATC Transcription Factors ; genetics ; metabolism ; Pre-Eclampsia ; immunology ; metabolism ; Pregnancy ; STAT1 Transcription Factor ; genetics ; metabolism ; Transcription Factor AP-1 ; genetics ; metabolism ; Transcription Factors ; genetics ; metabolism ; Young Adult

OBJECTIVETo explore the changes in the gene expression profiles in HepG2 cells transfected by human hepatocyte growth factor (hHGF) and analyze the signal transduction pathway in liver fibrosis regulated by hHGF.

METHODA 20,000 gene cDNA microarray (Affymetrix) was used to examine the gene expressions in the HepG2 cells transfected by hHGF. The differentially expressed genes were identified and some genes with possible contribution to hepatic fibrosis were subjected to real-time PCR analysis.

RESULTThe differentially expressed genes were mostly transcription regulatory molecules, cytokines, signal transduction, glucose metabolism, lipid metabolism. The results of real-time PCR showed up-regulated STAT1 and MAPK1 expression in the cells as were consistent with genechip analysis results.

CONCLUSIONhHGF gene transfection results in the gene expression profile changes in HepG2 cells. HGF may regulate liver fibrosis via the JAK/STAT and MAPK pathways.

Gene Expression Profiling ; Gene Expression Regulation ; Hep G2 Cells ; Hepatocyte Growth Factor ; genetics ; metabolism ; Humans ; Janus Kinases ; metabolism ; Liver Cirrhosis ; genetics ; metabolism ; Mitogen-Activated Protein Kinase 1 ; metabolism ; STAT1 Transcription Factor ; metabolism ; Signal Transduction ; physiology ; Transfection

The aim of the present study was to identify a new candidate anti-inflammatory compound for use in the active stage of thyroid-associated ophthalmopathy (TAO). Benzylideneacetophenone compound JC3 [(2E)-3-(4-hydroxy-3-methoxyphenyl)phenylpro-2-en-l-one] was synthesized based on a structural modification of yakuchinone B, a constituent of the seeds of Alpinia oxyphylla, which belongs to the ginger family (Zingiberaceae), has been widely used in folk medicine as an anti-inflammatory phytochemical. Orbital fibroblasts were primarily cultured from patients with TAO, and the potential of JC3 to suppress the interferon (IFN)-gamma-induced protein (IP)-10/CXCL10 production in these cells was determined. IFN-gamma strongly increased the level of IP-10/CXCL10 in orbital fibroblasts from patients with TAO. JC3 exerted a significant inhibitory effect on the IFN-gamma-induced increase in IP-10/CXCL10 in a dose-dependent manner; its potency was greater than that of an identical concentration of yakuchinone B with no toxicity to cells at the concentration range used. Moreover, the constructed dimer and trimer polystructures of JC3, showed greater potency than JC3 in suppressing the IFN-gamma-induced production of IP-10/CXCL10. JC3 significantly attenuated the IP-10/CXCL10 mRNA expression induced by IFN-gamma, and a gel-shift assay showed that JC3 suppressed IFN-gamma-induced DNA binding of signal transducer and activator of transcription-1 (STAT-1) in TAO orbital fibroblasts. Our results provide initial evidence that the JC3 compound reduces the levels of IP-10/CXCL10 protein and mRNA induced by IFN-gamma in orbital fibroblasts of TAO patients. Therefore, JC3 might be considered as a future candidate for therapeutic application in TAO that exerts its effects by modulating the pathogenic mechanisms in orbital fibroblasts.
Cells, Cultured ; Chalcone/chemical synthesis/*pharmacology ; Chemokine CXCL10/genetics/*metabolism ; Diarylheptanoids/chemistry/pharmacology ; Fibroblasts/*drug effects/metabolism ; Graves Ophthalmopathy/*metabolism ; Humans ; Interferon-gamma/*metabolism ; Orbit/cytology ; RNA, Messenger/genetics/metabolism ; STAT1 Transcription Factor/genetics/*metabolism

OBJECTIVETo investigate the molecular mechanisms by which IFN-alpha regulated retinoic acid-induced gene G (RIG-G) expression.

METHODSThe expression of STAT1, p-STAT1 and RIG-G in IFN-alpha-treated NB4 cells was detected by Western blot. The roles of STAT1, STAT2 and IRF-9 in IFN-alpha-induced RIG-G expression were analyzed in STAT1-null U3A cells by cell transfection, reporter gene assay, co-immunoprecipitation and chromatin immunoprecipitaion.

RESULTSIn U3A cells, only when STAT2 and IRF-9 were co-transfected, the luciferase activities of RIG-G promoter-containing reporter gene could be highly increased about 8-fold compared with that in the control group. Moreover, in the absence of IFN-alpha, similar effects were observed in either IRF-9 co-transfected with wild type or mutant form of STAT2, whereas IFN-alpha could increase the transactivation activity of wild type STAT2 and IRF-9 by 6-fold compared with that without IFN-alpha, but had no effect on mutant STAT2. In addition, STAT2 could interact with IRF-9 and bind to the RIG-G promoter.

CONCLUSIONSTAT2 may interact with IRF-9 in a STAT1-independent manner. The complex STAT2/IRF-9 is the key factor mediating the expression of RIG-G gene regulated by IFN-alpha. This is a novel signal transduction cascade for IFN which is different from the classical JAK-STAT pathway.

Cell Line, Tumor ; Fibrosarcoma ; metabolism ; pathology ; Gene Expression Regulation, Neoplastic ; Humans ; Immunoprecipitation ; Interferon-Stimulated Gene Factor 3, gamma Subunit ; genetics ; metabolism ; Interferon-alpha ; pharmacology ; Intracellular Signaling Peptides and Proteins ; genetics ; metabolism ; Leukemia, Promyelocytic, Acute ; metabolism ; pathology ; Phosphorylation ; Plasmids ; STAT1 Transcription Factor ; genetics ; metabolism ; STAT2 Transcription Factor ; genetics ; metabolism ; Signal Transduction ; Transfection

OBJECTIVETo investigate the effect of Lianggesan on the expression of signal transducer and activator of transcription 1 (STAT1) in rats with lipopolysaccharide (LPS)-induced acute lung injury and explore the possible mechanisms of the therapeutic effects.

METHODSEndotoxemia was induced in Wistar rats by intravenous injection of LPS (5 mg/kg). The rats were randomly divided into 6 groups, namely the control group, acute lung injury group (LPS group), 3 Lianggesan groups treated at different doses, and LPS+DEX treatment group. Each group, except for the control group, was further divided into 5 subgroups and examined at 1, 2, 4, 8 and 16 h after LPS injection. Western blotting was used to detect the protein expression of STAT1 and p-STAT1 in the lung tissue.

RESULTSIn LPS group, the expression of STAT1 began to increase at 1 h following LPS injection, reaching the peak level at 4 h; the peak expression of p-STAT1 occurred at 2 h after LPS administration (P<0.01). Compared with LPS group, the 3 Lianggesan groups and DEX group showed significantly decreased expressions of STAT1 and p-STAT1 at 2, 4 and 8 h after LPS injection (P<0.05 or 0.01).

CONCLUSIONAbnormal expression of STAT1 occurs in the lung tissue in the event of ALI. Lianggesan can relieve LPS-induced acute lung injury in rats by decreasing the expression of STAT1 and p-STAT1.

Acute Lung Injury ; chemically induced ; drug therapy ; metabolism ; Animals ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Female ; Lipopolysaccharides ; Lung ; metabolism ; Random Allocation ; Rats ; Rats, Wistar ; STAT1 Transcription Factor ; genetics ; metabolism

OBJECTIVETo study the mechanism of signal transduction in anti-HBV action of IFN-alpha.

METHODSThe HBV DNA in HepG 2.2.15 cell line supernatant with/without IFNalpha-2b were monitored by fluorescence real-time quantitive PCR. STAT1, STAT2, ISGF3-gamma, PKR, 2'5'-OAS mRNA levels from HepG 2 and HepG 2.2.15 cell lines that were treated with/without IFNalpha-2b at different times were detected by semi-quantitive RT-PCR. And the ISGF3-gamma protein was detected by Western blot. Then, these items were detected again after inhibiting the JAK-STAT pathway with genistein.

RESULTSThe HBV DNA in 2215 supernatant that were treated with IFNalpha-2b for 8 hours decreased 0.72 log 10 copies/ml. But the basal levels of DNA in cells pretreated with genistein? followed by IFNalpha-2b did not decrease. The STAT1, STAT2, ISGF3-gamma, 2'5'-OAS, PKR mRNA levels were upregulated by IFNalpha-2b. The same phenomena were observed with STAT1, STAT2, ISGF3-gamma mRNA when pretreated with genistein then treated with IFNalpha-2b, but the levels of 2'5'-OAS, PKR mRNA were decreased in this situation. The expression of the protein of ISGF3-gamma was also augmented by IFNalpha-2b, and was blocked by genistein.

CONCLUSIONThe JAK-STAT pathway seems to be a critical pathway in IFNalpha-2b action against HBV? and ISGF3 is most probably a key factor of the route.

Antiviral Agents ; pharmacology ; Blotting, Western ; Cell Line, Tumor ; DNA, Viral ; genetics ; isolation & purification ; Gene Expression Regulation, Neoplastic ; drug effects ; Hepatitis B virus ; drug effects ; genetics ; growth & development ; Humans ; Interferon-Stimulated Gene Factor 3 ; genetics ; metabolism ; Interferon-Stimulated Gene Factor 3, gamma Subunit ; genetics ; metabolism ; Interferon-alpha ; pharmacology ; Polymerase Chain Reaction ; RNA, Messenger ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; STAT1 Transcription Factor ; genetics ; metabolism ; STAT2 Transcription Factor ; genetics ; metabolism ; Signal Transduction