Cytosolic retinoic acid-inducible gene I（RIG-I） is an important innate immune RNA sensor and can induce antiviral cytokines, e.g., interferon-β（IFN-β）. Innate immune response to hepatitis B virus（HBV） plays a ...Cytosolic retinoic acid-inducible gene I（RIG-I） is an important innate immune RNA sensor and can induce antiviral cytokines, e.g., interferon-β（IFN-β）. Innate immune response to hepatitis B virus（HBV） plays a pivotal role in viral clearance and persistence. However, knowledge of the role that RIG-I plays in HBV infection is limited. The woodchuck is a valuable model for studying HBV infection. To characterize the molecular basis of woodchuck RIG-I（w RIG-I）, we analyzed the complete coding sequences（CDSs） of w RIG-I, containing 2778 base pairs that encode 925 amino acids. The deduced w RIG-I protein was 106.847 k D with a theoretical isoelectric point（p I） of 6.07, and contained three important functional structures [caspase activation and recruitment domains（CARDs）, DEx D/H-box helicases, and a repressor domain（RD）]. In woodchuck fibroblastoma cell line（WH12/6）, w RIG-I-targeted small interfering RNA（si RNA） down-regulated RIG-I and its downstrean effector–IFN-β transcripts under RIG-I＇ ligand, 5＇-ppp double stranded RNA（ds RNA） stimulation. We also measured m RNA levels of w RIG-I in different tissues from healthy woodchucks and in the livers from woodchuck hepatitis virus（WHV）-infected woodchucks. The basal expression levels of w RIG-I were abundant in the kidney and liver. Importantly, w RIG-I was significantly up-regulated in acutely infected woodchuck livers, suggesting that RIG-I might be involved in WHV infection. These results may characterize RIG-I in the woodchuck model, providing a strong basis for further study on RIG-I-mediated innate immunity in HBV infection.展开更多
Tazarotene-induced gene 1(TIG1)is induced by a derivative of vitamin A and is known to regulate many important biological processes and control the development of cancer.TIG1 is widely expressed in various tissues;yet...Tazarotene-induced gene 1(TIG1)is induced by a derivative of vitamin A and is known to regulate many important biological processes and control the development of cancer.TIG1 is widely expressed in various tissues;yet in many cancer tissues,it is not expressed because of the methylation of its promoter.Additionally,the expression of TIG1 in cancer cells inhibits their growth and invasion,suggesting that TIG1 acts as a tumor suppressor gene.However,in some cancers,poor prognosis is associated with TIG1 expression,indicating its protumor growth characteristics,especially in promoting the invasion of inflammatory breast cancer cells.This review comprehensively summarizes the roles of the TIG1 gene in cancer development and details the mechanisms through which TIG1 regulates cancer development,with the aim of understanding its various roles in cancer development.展开更多
Objective： To observe the anti-virus effects of andrographolide （AD） on the retinoic acid-inducible gene-I （RIG-I）-Iike receptors （RLRs） signaling pathway when immunological cells were infected with HIN1. Meth...Objective： To observe the anti-virus effects of andrographolide （AD） on the retinoic acid-inducible gene-I （RIG-I）-Iike receptors （RLRs） signaling pathway when immunological cells were infected with HIN1. Methods： Leukomonocyte was obtained from umbilical cord blood by Ficoll density gradient centrifugation, and immunological cells were harvested after cytokines stimulation. Virus infected cell model was established by H1N1 co-cultured with normal human bronchial epithelial cell line （16HBE）. The optimal concentration of AD was defined by methyl-thiazolyl-tetrazolium （MTT） assay. After the virus infected cell model was established, AD was added into the medium as a treatment intervention. After 24-h co-culture, cell supernatant was collected for interferon gamma （IFN- ~, ） and interleukin-4 （IL-4） enzyme-linked immunosorbent assay （ELISA） detection while immunological cells for real-time polymerase chain reaction （RT-PCR）. Results： The optimal concentration of AD for anti-virus effect was 250 μg/mL. IL-4 and IFN-γ in the supernatant and mRNA levels in RLRs pathway increased when cells was infected by virus, RIG-I, IFN-13 promoter stimulator-1 （IPS-1）, interferon regulatory factor （IRF）-7, IRF-3 and nuclear transcription factor K B （NF- K B） mRNA levels increased significantly （P〈0.05）. When AD was added into co-culture medium, the levels of IL-4 and IFN-γ were lower than those in the non-interference groups and the mRNA expression levels decreased, RIG-I, IPS-1, IRF-7, IRF-3 and NF- K B decreased significantly in each group with significant statistic differences （P〈0.05）. Conclusions： The RLRs mediated viral recognition provided a potential molecular target for acute viral infections and andrographolide could ameliorate H1N1 virus-induced cell mortality. And the antiviral effects might be related to its inhibition of viral-induced activation of the RLRs signaling pathway.展开更多
The HIV-1 LTR controls the expression of HIV-1 viral genes and thus is critical for viral propagation and pathology. Numerous host factors have been shown to participate in the regulation of the LTR promoter. Among th...The HIV-1 LTR controls the expression of HIV-1 viral genes and thus is critical for viral propagation and pathology. Numerous host factors have been shown to participate in the regulation of the LTR promoter. Among them is the thyroid hormone (T3) receptor (TR). TR has been shown to bind to the critical region of the promoter that contain the NFbB and Sp1 binding sites. Interestingly, earlier transient transfection studies in tissue culture cells have yielded contradicting conclusions on the role of TR in LTR regulation, likely due to the use of different cell types and/or lack of proper chromatin organization. Here, using the frog oocyte as a model system that allows replication-coupled chromatin assembly, mimicking that in somatic cells, we demonstrate that unliganded heterodimers of TR and RXR (9-cis retinoic acid receptor) repress LTR while the addition of T3 relieves the repression and further activates the promoter. More importantly, we show that chromatin and unliganded TR/RXR synergize to repress the promoter in a histone deacetylase-dependent manner.展开更多
Hepatitis C virus(HCV)frequently elicits only mild immune responses so that it can often establish chronic infection.In this case HCV antigens persist and continue to stimulate the immune system.Antigen persistence th...Hepatitis C virus(HCV)frequently elicits only mild immune responses so that it can often establish chronic infection.In this case HCV antigens persist and continue to stimulate the immune system.Antigen persistence then leads to profound changes in the infected host’s immune responsiveness,and eventually contributes to the pathology of chronic hepatitis.This topic highlight summarizes changes associated with chronic hepatitis C concerning innate immunity(interferons,natural killer cells),adaptive immune responses(immunoglobulins,T cells,and mechanisms of immune regulation(regulatory T cells).Our overview clarifies that a strong anti-HCV immune response is frequently associated with acute severe tissue damage.In chronic hepatitis C,however,the effector arms of the immune system either become refractory to activation or take over regulatory functions.Taken together these changes in immunity may lead to persistent liver damage and cirrhosis.Consequently,effector arms of the immune system will not only be considered with respect to antiviral defence but also as pivotal mechanisms of inflammation,necrosis and progression to cirrhosis.Thus,avoiding Scylla-a strong,sustained antiviral immune response with inital tissue damage-takes the infected host to virus-triggered immunopathology,which ultimately leads to cirrhosis and liver cancerthe realm of Charybdis.展开更多
非特异性固有免疫是预防病毒感染的第一道防线,Toll样受体(toll-like receptors,TLRs)和维甲酸诱导基因I样受体(RIG-I like receptors,RLRs)是感知病毒RNA的两个主要受体家族。RLRs为存在于胞浆中的RNA解旋酶家族,可识别在病毒感染或复...非特异性固有免疫是预防病毒感染的第一道防线,Toll样受体(toll-like receptors,TLRs)和维甲酸诱导基因I样受体(RIG-I like receptors,RLRs)是感知病毒RNA的两个主要受体家族。RLRs为存在于胞浆中的RNA解旋酶家族,可识别在病毒感染或复制期间进入到胞浆内的单链或双链RNA。目前研究RLRs家族比较多的成员有维甲酸诱导型基因I(retinoic acid-inducible gene I,RIG-I)、黑色素瘤分化相关基因5(melanoma differentiation associated gene-5,MDA-5)及遗传学和生理学实验室蛋白2(laboratory of genetics and physiology 2,LGP2)。本文分别就RLRs家族中RIG-I和MDA-5结构、生物学作用及其信号传导中关键分子的研究进展作一概述。展开更多
基金supported by grants from the National Science and Technology Major Project for Infectious Diseases of China(No.2012ZX10004503)the National Natural Science Foundation of China(No.81101248,No.81261120397 and No.81371828)the Deutsche Forschungs-gemeinschaft(Transregio TRR60)
文摘Cytosolic retinoic acid-inducible gene I（RIG-I） is an important innate immune RNA sensor and can induce antiviral cytokines, e.g., interferon-β（IFN-β）. Innate immune response to hepatitis B virus（HBV） plays a pivotal role in viral clearance and persistence. However, knowledge of the role that RIG-I plays in HBV infection is limited. The woodchuck is a valuable model for studying HBV infection. To characterize the molecular basis of woodchuck RIG-I（w RIG-I）, we analyzed the complete coding sequences（CDSs） of w RIG-I, containing 2778 base pairs that encode 925 amino acids. The deduced w RIG-I protein was 106.847 k D with a theoretical isoelectric point（p I） of 6.07, and contained three important functional structures [caspase activation and recruitment domains（CARDs）, DEx D/H-box helicases, and a repressor domain（RD）]. In woodchuck fibroblastoma cell line（WH12/6）, w RIG-I-targeted small interfering RNA（si RNA） down-regulated RIG-I and its downstrean effector–IFN-β transcripts under RIG-I＇ ligand, 5＇-ppp double stranded RNA（ds RNA） stimulation. We also measured m RNA levels of w RIG-I in different tissues from healthy woodchucks and in the livers from woodchuck hepatitis virus（WHV）-infected woodchucks. The basal expression levels of w RIG-I were abundant in the kidney and liver. Importantly, w RIG-I was significantly up-regulated in acutely infected woodchuck livers, suggesting that RIG-I might be involved in WHV infection. These results may characterize RIG-I in the woodchuck model, providing a strong basis for further study on RIG-I-mediated innate immunity in HBV infection.
基金supported by the Taipei Tzu Chi Hospital through grants from the Buddhist Tzu Chi Medical Foundation under the Numbers TCRD-TPE-111-23(2/3)and TCRD-TPE-113-20,Taipei,Taiwan.
文摘Tazarotene-induced gene 1(TIG1)is induced by a derivative of vitamin A and is known to regulate many important biological processes and control the development of cancer.TIG1 is widely expressed in various tissues;yet in many cancer tissues,it is not expressed because of the methylation of its promoter.Additionally,the expression of TIG1 in cancer cells inhibits their growth and invasion,suggesting that TIG1 acts as a tumor suppressor gene.However,in some cancers,poor prognosis is associated with TIG1 expression,indicating its protumor growth characteristics,especially in promoting the invasion of inflammatory breast cancer cells.This review comprehensively summarizes the roles of the TIG1 gene in cancer development and details the mechanisms through which TIG1 regulates cancer development,with the aim of understanding its various roles in cancer development.
基金Supported by the National Natural Science Foundation of China(No.81273616 and 30973693)the Doctoral Fund of the Ministryof Education 2010(No.20104401110003)the Natural Science Foundation of Guangdong Province(No.S2013010013434)
文摘Objective： To observe the anti-virus effects of andrographolide （AD） on the retinoic acid-inducible gene-I （RIG-I）-Iike receptors （RLRs） signaling pathway when immunological cells were infected with HIN1. Methods： Leukomonocyte was obtained from umbilical cord blood by Ficoll density gradient centrifugation, and immunological cells were harvested after cytokines stimulation. Virus infected cell model was established by H1N1 co-cultured with normal human bronchial epithelial cell line （16HBE）. The optimal concentration of AD was defined by methyl-thiazolyl-tetrazolium （MTT） assay. After the virus infected cell model was established, AD was added into the medium as a treatment intervention. After 24-h co-culture, cell supernatant was collected for interferon gamma （IFN- ~, ） and interleukin-4 （IL-4） enzyme-linked immunosorbent assay （ELISA） detection while immunological cells for real-time polymerase chain reaction （RT-PCR）. Results： The optimal concentration of AD for anti-virus effect was 250 μg/mL. IL-4 and IFN-γ in the supernatant and mRNA levels in RLRs pathway increased when cells was infected by virus, RIG-I, IFN-13 promoter stimulator-1 （IPS-1）, interferon regulatory factor （IRF）-7, IRF-3 and nuclear transcription factor K B （NF- K B） mRNA levels increased significantly （P〈0.05）. When AD was added into co-culture medium, the levels of IL-4 and IFN-γ were lower than those in the non-interference groups and the mRNA expression levels decreased, RIG-I, IPS-1, IRF-7, IRF-3 and NF- K B decreased significantly in each group with significant statistic differences （P〈0.05）. Conclusions： The RLRs mediated viral recognition provided a potential molecular target for acute viral infections and andrographolide could ameliorate H1N1 virus-induced cell mortality. And the antiviral effects might be related to its inhibition of viral-induced activation of the RLRs signaling pathway.
文摘The HIV-1 LTR controls the expression of HIV-1 viral genes and thus is critical for viral propagation and pathology. Numerous host factors have been shown to participate in the regulation of the LTR promoter. Among them is the thyroid hormone (T3) receptor (TR). TR has been shown to bind to the critical region of the promoter that contain the NFbB and Sp1 binding sites. Interestingly, earlier transient transfection studies in tissue culture cells have yielded contradicting conclusions on the role of TR in LTR regulation, likely due to the use of different cell types and/or lack of proper chromatin organization. Here, using the frog oocyte as a model system that allows replication-coupled chromatin assembly, mimicking that in somatic cells, we demonstrate that unliganded heterodimers of TR and RXR (9-cis retinoic acid receptor) repress LTR while the addition of T3 relieves the repression and further activates the promoter. More importantly, we show that chromatin and unliganded TR/RXR synergize to repress the promoter in a histone deacetylase-dependent manner.
文摘Hepatitis C virus(HCV)frequently elicits only mild immune responses so that it can often establish chronic infection.In this case HCV antigens persist and continue to stimulate the immune system.Antigen persistence then leads to profound changes in the infected host’s immune responsiveness,and eventually contributes to the pathology of chronic hepatitis.This topic highlight summarizes changes associated with chronic hepatitis C concerning innate immunity(interferons,natural killer cells),adaptive immune responses(immunoglobulins,T cells,and mechanisms of immune regulation(regulatory T cells).Our overview clarifies that a strong anti-HCV immune response is frequently associated with acute severe tissue damage.In chronic hepatitis C,however,the effector arms of the immune system either become refractory to activation or take over regulatory functions.Taken together these changes in immunity may lead to persistent liver damage and cirrhosis.Consequently,effector arms of the immune system will not only be considered with respect to antiviral defence but also as pivotal mechanisms of inflammation,necrosis and progression to cirrhosis.Thus,avoiding Scylla-a strong,sustained antiviral immune response with inital tissue damage-takes the infected host to virus-triggered immunopathology,which ultimately leads to cirrhosis and liver cancerthe realm of Charybdis.
文摘非特异性固有免疫是预防病毒感染的第一道防线,Toll样受体(toll-like receptors,TLRs)和维甲酸诱导基因I样受体(RIG-I like receptors,RLRs)是感知病毒RNA的两个主要受体家族。RLRs为存在于胞浆中的RNA解旋酶家族,可识别在病毒感染或复制期间进入到胞浆内的单链或双链RNA。目前研究RLRs家族比较多的成员有维甲酸诱导型基因I(retinoic acid-inducible gene I,RIG-I)、黑色素瘤分化相关基因5(melanoma differentiation associated gene-5,MDA-5)及遗传学和生理学实验室蛋白2(laboratory of genetics and physiology 2,LGP2)。本文分别就RLRs家族中RIG-I和MDA-5结构、生物学作用及其信号传导中关键分子的研究进展作一概述。
