Zika virus(ZIKV),a positive-sense single-stranded RNA virus,causes congenital ZIKV syndrome in children and Guillain-Barre Syndrome(GBS)in adults.ZIKV expresses nonstructural protein 5(NS5),a large protein that is ess...Zika virus(ZIKV),a positive-sense single-stranded RNA virus,causes congenital ZIKV syndrome in children and Guillain-Barre Syndrome(GBS)in adults.ZIKV expresses nonstructural protein 5(NS5),a large protein that is essential for viral replication.ZIKV NS5 confers the ability to evade interferon(IFN)signalling;however,the exact mechanism remains unclear.In this study,we employed affinity pull-down and liquid chromatography-tandem mass spectrometry(LC-MS/MS)analyses and found that splicing factor 3b subunit 3(SF3B3)is associated with the NS5-Flag pull-down complex through interaction with NS5.Functional assays showed that SF3B3 overexpression inhibited ZIKV replication by promoting IFN-stimulated gene(ISG)expression whereas silencing of SF3B3 inhibited expression of ISGs to promote ZIKV replication.GTP cyclohydrolase I(GCH1)is the first and ratelimiting enzyme in tetrahydrobiopterin(BH4)biosynthesis.NS5 upregulates the expression of GCH1 during ZIKV infection.And GCH1 marginally promoted ZIKV replication via the IFN pathway.Additionally,GCH1 expression is related to the regulation of SF3B3.Overexpression of the SF3B3 protein effectively reduced GCH1 protein levels,whereas SF3B3 knockdown increased its levels.These findings indicated that ZIKV NS5 binding protein SF3B3 contributed to the host immune response against ZIKV replication by modulating the expression of GCH1.展开更多
Chronic active hepatitis(CAH) is acknowledged as an imperative risk factor for the development of liver injury and hepatocellular carcinoma.The histological end points of CAH are chronic inflammation,fibrosis and cirr...Chronic active hepatitis(CAH) is acknowledged as an imperative risk factor for the development of liver injury and hepatocellular carcinoma.The histological end points of CAH are chronic inflammation,fibrosis and cirrhosis which are coupled with increased DNA synthesis in cirrhotic vs healthy normal livers.The potential mechanism involved in CAH includes a combination of processes leading to liver cell necrosis,inflammation and cytokine production and liver scaring(fibrosis).The severity of liver damage is regulated by Hepatitis B virus genotypes and viral components.The viral and cellular factors that contribute to liver injury are discussed in this article.Liver injury caused by the viral infection affects many cellular processes such as cell signaling,apoptosis,transcription,DNA repair which in turn induce radical effects on cell survival,growth,transformation and maintenance.The consequence of such perturbations is resulted in the alteration of bile secretion,gluconeogenesis,glycolysis,detoxification and metabolism of carbohydrates,proteins,fat and balance of nutrients.The identification and elucidation of the molecular pathways perturbed by the viral proteins are important in order to design effective strategy to minimize and/or restore the hepatocytes injury.展开更多
Objective: The aim of the study was to investigate the effect of lipopolysaccharide(LPS) on the expression of nuclear factor kappa B(NF-κB) in 4-(methylitrosamino)-1-(3-pyridyl)-1-butanone(NNK)-mediated primary mouse...Objective: The aim of the study was to investigate the effect of lipopolysaccharide(LPS) on the expression of nuclear factor kappa B(NF-κB) in 4-(methylitrosamino)-1-(3-pyridyl)-1-butanone(NNK)-mediated primary mouse peritoneal macrophages in vitro. Methods: The activity of peritoneal macrophages treated with different concentrations of LPS was detected by MTT assay in rider to find the optimal concentration. Peritoneal macrophages were also treated with NNK(100–500 μM), with or without LPS for 9 h. The expression of NF-κB was demonstrated via immunocytochemistry(ICC) and Westernblot, respectively. Results: The concentration of LPS at 25 μg/mL was found to be the optimal concentration to improve the activity of peritoneal macrophages(P < 0.01). Simultaneously, LPS(25 μg/mL) increased the expression of NF-κB in both the nucleus and cytoplasm and facilitated transfer of NF-κB to the nucleus. NNK treatment significantly inhibited the expression of NF-κB in a concentration-dependent manner, among the LPS-stimulated or unstimulated peritoneal macrophages, especially when cotreated with LPS(25 μg/mL, P < 0.01). Furthermore, NNK treatment(500 μM) with LPS yielded a significant decrease in NF-κB translocation to nucleus and inhibited the expression of NF-κB(P < 0.005). Conclusion: LPS enhances the suppression of NF-κB expression in NNK-mediated mouse peritoneal macrophages, which may provide a theoretical basis for the inhibition of cancer.展开更多
Zika virus(ZIKV)evolves non-structural proteins to evade immune response and ensure efficient replication in the host cells.Cholesterol metabolic enzyme 7-dehydrocholesterol reductase(DHCR7)was recently reported to im...Zika virus(ZIKV)evolves non-structural proteins to evade immune response and ensure efficient replication in the host cells.Cholesterol metabolic enzyme 7-dehydrocholesterol reductase(DHCR7)was recently reported to impact innate immune responses in ZIKV infection.However,the vital non-structural protein and mechanisms involved in DHCR7-mediated viral evasion are not well elucidated.In this study,we demonstrated that ZIKV infection facilitated DHCR7 expression.Notably,the upregulated DHCR7 in turn facilitated ZIKV infection and blocking DHCR7 suppressed ZIKV infection.Mechanically,ZIKV non-structural protein 4B(NS4B)interacted with DHCR7 to induce DHCR7 expression.Moreover,DHCR7 inhibited TANK-binding kinase 1(TBK1)and interferon regulatory factor 3(IRF3)phosphorylation,which resulted in the reduction of interferon-beta(IFN-β)and interferon-stimulated genes(ISGs)productions.Therefore,we propose that ZIKV NS4B binds to DHCR7 to repress TBK1 and IRF3 activation,which in turn inhibits IFN-βand ISGs,and thereby facilitating ZIKV evasion.This study broadens the insights on how viral non-structural proteins antagonize innate immunity to facilitate viral infection via cholesterol metabolic enzymes and intermediates.展开更多
基金supported by the National Key R&D Project of China(2021YFC230170402)CAMS Innovation Fund for Medical Sciences(2021-1-I2M-038).
文摘Zika virus(ZIKV),a positive-sense single-stranded RNA virus,causes congenital ZIKV syndrome in children and Guillain-Barre Syndrome(GBS)in adults.ZIKV expresses nonstructural protein 5(NS5),a large protein that is essential for viral replication.ZIKV NS5 confers the ability to evade interferon(IFN)signalling;however,the exact mechanism remains unclear.In this study,we employed affinity pull-down and liquid chromatography-tandem mass spectrometry(LC-MS/MS)analyses and found that splicing factor 3b subunit 3(SF3B3)is associated with the NS5-Flag pull-down complex through interaction with NS5.Functional assays showed that SF3B3 overexpression inhibited ZIKV replication by promoting IFN-stimulated gene(ISG)expression whereas silencing of SF3B3 inhibited expression of ISGs to promote ZIKV replication.GTP cyclohydrolase I(GCH1)is the first and ratelimiting enzyme in tetrahydrobiopterin(BH4)biosynthesis.NS5 upregulates the expression of GCH1 during ZIKV infection.And GCH1 marginally promoted ZIKV replication via the IFN pathway.Additionally,GCH1 expression is related to the regulation of SF3B3.Overexpression of the SF3B3 protein effectively reduced GCH1 protein levels,whereas SF3B3 knockdown increased its levels.These findings indicated that ZIKV NS5 binding protein SF3B3 contributed to the host immune response against ZIKV replication by modulating the expression of GCH1.
文摘Chronic active hepatitis(CAH) is acknowledged as an imperative risk factor for the development of liver injury and hepatocellular carcinoma.The histological end points of CAH are chronic inflammation,fibrosis and cirrhosis which are coupled with increased DNA synthesis in cirrhotic vs healthy normal livers.The potential mechanism involved in CAH includes a combination of processes leading to liver cell necrosis,inflammation and cytokine production and liver scaring(fibrosis).The severity of liver damage is regulated by Hepatitis B virus genotypes and viral components.The viral and cellular factors that contribute to liver injury are discussed in this article.Liver injury caused by the viral infection affects many cellular processes such as cell signaling,apoptosis,transcription,DNA repair which in turn induce radical effects on cell survival,growth,transformation and maintenance.The consequence of such perturbations is resulted in the alteration of bile secretion,gluconeogenesis,glycolysis,detoxification and metabolism of carbohydrates,proteins,fat and balance of nutrients.The identification and elucidation of the molecular pathways perturbed by the viral proteins are important in order to design effective strategy to minimize and/or restore the hepatocytes injury.
文摘Objective: The aim of the study was to investigate the effect of lipopolysaccharide(LPS) on the expression of nuclear factor kappa B(NF-κB) in 4-(methylitrosamino)-1-(3-pyridyl)-1-butanone(NNK)-mediated primary mouse peritoneal macrophages in vitro. Methods: The activity of peritoneal macrophages treated with different concentrations of LPS was detected by MTT assay in rider to find the optimal concentration. Peritoneal macrophages were also treated with NNK(100–500 μM), with or without LPS for 9 h. The expression of NF-κB was demonstrated via immunocytochemistry(ICC) and Westernblot, respectively. Results: The concentration of LPS at 25 μg/mL was found to be the optimal concentration to improve the activity of peritoneal macrophages(P < 0.01). Simultaneously, LPS(25 μg/mL) increased the expression of NF-κB in both the nucleus and cytoplasm and facilitated transfer of NF-κB to the nucleus. NNK treatment significantly inhibited the expression of NF-κB in a concentration-dependent manner, among the LPS-stimulated or unstimulated peritoneal macrophages, especially when cotreated with LPS(25 μg/mL, P < 0.01). Furthermore, NNK treatment(500 μM) with LPS yielded a significant decrease in NF-κB translocation to nucleus and inhibited the expression of NF-κB(P < 0.005). Conclusion: LPS enhances the suppression of NF-κB expression in NNK-mediated mouse peritoneal macrophages, which may provide a theoretical basis for the inhibition of cancer.
基金supported by the National Natural Science Foundation of China(81730061,81802008)the Guangdong Basic and Applied Basic Research Foundation(2021A1515011272).
文摘Zika virus(ZIKV)evolves non-structural proteins to evade immune response and ensure efficient replication in the host cells.Cholesterol metabolic enzyme 7-dehydrocholesterol reductase(DHCR7)was recently reported to impact innate immune responses in ZIKV infection.However,the vital non-structural protein and mechanisms involved in DHCR7-mediated viral evasion are not well elucidated.In this study,we demonstrated that ZIKV infection facilitated DHCR7 expression.Notably,the upregulated DHCR7 in turn facilitated ZIKV infection and blocking DHCR7 suppressed ZIKV infection.Mechanically,ZIKV non-structural protein 4B(NS4B)interacted with DHCR7 to induce DHCR7 expression.Moreover,DHCR7 inhibited TANK-binding kinase 1(TBK1)and interferon regulatory factor 3(IRF3)phosphorylation,which resulted in the reduction of interferon-beta(IFN-β)and interferon-stimulated genes(ISGs)productions.Therefore,we propose that ZIKV NS4B binds to DHCR7 to repress TBK1 and IRF3 activation,which in turn inhibits IFN-βand ISGs,and thereby facilitating ZIKV evasion.This study broadens the insights on how viral non-structural proteins antagonize innate immunity to facilitate viral infection via cholesterol metabolic enzymes and intermediates.
