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de Bruin ACM, Spronken MI, Bestebroer TM, Fouchier RAM, Richard M. Conserved Expression and Functionality of Furin between Chickens and Ducks as an Activating Protease of Highly Pathogenic Avian Influenza Virus Hemagglutinins. Microbiol Spectr 2023; 11:e0460222. [PMID: 36916982 PMCID: PMC10100678 DOI: 10.1128/spectrum.04602-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 02/23/2023] [Indexed: 03/15/2023] Open
Abstract
Highly pathogenic avian influenza viruses (HPAIVs) typically emerge from low-pathogenic avian influenza viruses (LPAIVs) of the H5 and H7 subtypes upon spillover from wild aquatic birds into poultry. The conversion from LPAIV to HPAIV is characterized by the acquisition of a multibasic cleavage site (MBCS) at the proteolytic cleavage site in the viral binding and fusion protein, hemagglutinin (HA), resulting in cleavage and activation of HA by ubiquitously expressed furin-like proteases. The ensuing HPAIVs disseminate systemically in gallinaceous poultry, are endotheliotropic, and cause hemorrhagic disease with high mortality. HPAIV infections in wild aquatic birds are generally milder, often asymptomatic, and generally not associated with systemic dissemination nor endotheliotropic. As MBCS cleavage by host proteases is the main virulence determinant of HPAIVs in poultry, we set out to determine whether cleavage of HPAIV HA by host proteases might influence the observed species-specific pathogenesis and tropism. Here, we sequenced, cloned, and characterized the expression and functionality of duck furin. The furin sequence was strongly conserved between chickens and ducks, and duck furin cleaved HPAIV and tetrabasic HA in an overexpression system, confirming its functionality. Furin was expressed ubiquitously and to similar extents in duck and chicken tissues, including in primary duck endothelial cells, which sustained multicycle replication of H5N1 HPAIV but not LPAIVs. In conclusion, differences in furin-like protease biology between wild aquatic birds and gallinaceous poultry are unlikely to largely determine the stark differences observed in species-specific pathogenesis of HPAIVs. IMPORTANCE HPAIV outbreaks are a global concern due to the health risks for poultry, wildlife, and humans and their major economic impact. The number of LPAIV-to-HPAIV conversions, which is associated with spillover from wild birds to poultry, has been increasing over recent decades. Furthermore, H5 HPAIVs from the A/goose/Guangdong/1/96 lineage have been circulating in migratory birds, causing increasingly frequent epizootics in poultry and wild birds. Milder symptoms in migratory birds allow for dispersion of HPAIVs over long distances, justifying the importance of understanding the pathogenesis of HPAIVs in wild birds. Here, we examined whether host proteases are a likely candidate to explain some differences in the degree of HPAIV systemic dissemination between avian species. This is the first report to show that furin function and expression is comparable between chickens and ducks, which renders the hypothesis unlikely that furin-like protease differences influence the HPAIV species-specific pathogenesis and tropism.
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Affiliation(s)
- Anja C. M. de Bruin
- Department of Viroscience, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Monique I. Spronken
- Department of Viroscience, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Theo M. Bestebroer
- Department of Viroscience, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Ron A. M. Fouchier
- Department of Viroscience, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Mathilde Richard
- Department of Viroscience, Erasmus Medical Center, Rotterdam, the Netherlands
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Li YY, Kuroki K, Shimakami T, Murai K, Kawaguchi K, Shirasaki T, Nio K, Sugimoto S, Nishikawa T, Okada H, Orita N, Takayama H, Wang Y, Thi Bich PD, Ishida A, Iwabuchi S, Hashimoto S, Shimaoka T, Tabata N, Watanabe-Takahashi M, Nishikawa K, Yanagawa H, Seiki M, Matsushima K, Yamashita T, Kaneko S, Honda M. Hepatitis B Virus Utilizes a Retrograde Trafficking Route via the Trans-Golgi Network to Avoid Lysosomal Degradation. Cell Mol Gastroenterol Hepatol 2023; 15:533-558. [PMID: 36270602 PMCID: PMC9868690 DOI: 10.1016/j.jcmgh.2022.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 10/11/2022] [Accepted: 10/12/2022] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Hepatitis B virus (HBV) infection is difficult to cure owing to the persistence of covalently closed circular viral DNA (cccDNA). We performed single-cell transcriptome analysis of newly established HBV-positive and HBV-negative hepatocellular carcinoma cell lines and found that dedicator of cytokinesis 11 (DOCK11) was crucially involved in HBV persistence. However, the roles of DOCK11 in the HBV lifecycle have not been clarified. METHODS The cccDNA levels were measured by Southern blotting and real-time detection polymerase chain reaction in various hepatocytes including PXB cells by using an HBV-infected model. The retrograde trafficking route of HBV capsid was investigated by super-resolution microscopy, proximity ligation assay, and time-lapse analysis. The downstream molecules of DOCK11 and underlying mechanism were examined by liquid chromatography-tandem mass spectrometry, immunoblotting, and enzyme-linked immunosorbent assay. RESULTS The cccDNA levels were strongly increased by DOCK11 overexpression and repressed by DOCK11 suppression. Interestingly, DOCK11 functionally associated with retrograde trafficking proteins in the trans-Golgi network (TGN), Arf-GAP with GTPase domain, ankyrin repeat, and pleckstrin homology domain-containing protein 2 (AGAP2), and ADP-ribosylation factor 1 (ARF1), together with HBV capsid, to open an alternative retrograde trafficking route for HBV from early endosomes (EEs) to the TGN and then to the endoplasmic reticulum (ER), thereby avoiding lysosomal degradation. Clinically, DOCK11 levels in liver biopsies from patients with chronic hepatitis B were significantly reduced by entecavir treatment, and this reduction correlated with HBV surface antigen levels. CONCLUSIONS HBV uses a retrograde trafficking route via EEs-TGN-ER for infection that is facilitated by DOCK11 and serves to maintain cccDNA. Therefore, DOCK11 is a potential therapeutic target to prevent persistent HBV infection.
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Affiliation(s)
- Ying-Yi Li
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Kazuyuki Kuroki
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Tetsuro Shimakami
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Kazuhisa Murai
- Department of Clinical Laboratory Medicine, Kanazawa University Graduate School of Health Medicine, Kanazawa, Japan
| | - Kazunori Kawaguchi
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Takayoshi Shirasaki
- Department of Clinical Laboratory Medicine, Kanazawa University Graduate School of Health Medicine, Kanazawa, Japan
| | - Kouki Nio
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Saiho Sugimoto
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Tomoki Nishikawa
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Hikari Okada
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Noriaki Orita
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Hideo Takayama
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Ying Wang
- Department of Clinical Laboratory Medicine, Kanazawa University Graduate School of Health Medicine, Kanazawa, Japan
| | - Phuong Doan Thi Bich
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Astuya Ishida
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Sadahiro Iwabuchi
- Department of Molecular Pathophysiology, Institute of Advanced Medicine, Wakayama Medical University, Wakayama, Japan
| | - Shinichi Hashimoto
- Department of Molecular Pathophysiology, Institute of Advanced Medicine, Wakayama Medical University, Wakayama, Japan
| | - Takeshi Shimaoka
- Division of Molecular Regulation of Inflammatory and Immune Diseases, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan
| | | | | | - Kiyotaka Nishikawa
- Department of Molecular Life Sciences, Doshisha University, Kyoto, Japan
| | | | - Motoharu Seiki
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Kouji Matsushima
- Division of Molecular Regulation of Inflammatory and Immune Diseases, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan
| | - Taro Yamashita
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Shuichi Kaneko
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan
| | - Masao Honda
- Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan; Department of Clinical Laboratory Medicine, Kanazawa University Graduate School of Health Medicine, Kanazawa, Japan.
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Khattab ESAEH, Ragab A, Abol-Ftouh MA, Elhenawy AA. Therapeutic strategies for Covid-19 based on molecular docking and dynamic studies to the ACE-2 receptors, Furin, and viral spike proteins. J Biomol Struct Dyn 2022; 40:13291-13309. [PMID: 34647855 PMCID: PMC8544674 DOI: 10.1080/07391102.2021.1989036] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
SARS-CoV-2 is a pandemic virus that caused infections and deaths in many world countries, including the Middle East. The virus-infected human cells by binding via ACE-2 receptor through the Spike protein of the virus with Furin's help causing cell membrane fusion leading to Covid-19-cell entry. No registered drugs or vaccines are triggering this pandemic viral disease yet. Our present work is based on molecular docking and dynamics simulation that performed to spike protein-ACE-2 interface complex, ACE-2 receptor, Spike protein (RBD), and Furin as targets for new small molecules. These drugs target new potential therapies to show their probabilities toward the active sites of mentioned proteins, strongly causing inhibition and/or potential therapy for covid-19. All target proteins were estimated against new target compounds under clinical trials and repurposing drugs currently present. Possibilities of those molecules and potential therapeutics acting on a certain target were predicted. MD simulations over 200 ns with molecular mechanics-generalized Born surface area (MMGBSA) binding energy calculations were performed. The structural and energetic analyses demonstrated the stability of the ligands-MPros complex. Our present work will introduce new visions of some biologically active molecules for further studies in-vitro and in-vivo for Covid-19, repurposing of these molecules should be taking place under clinical works and offering different strategies for drugs repurposing against Covid-19 diseases.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
| | - Ahmed Ragab
- Department of Chemistry, Faculty of Science (Boys), Al-Azhar University, Nasr City, Cairo, Egypt,CONTACT Ahmed Ragab ; Department of Chemistry, Faculty of Science (Boys), Al-Azhar University, Nasr City, Cairo11884, Egypt
| | - Mahmoud A. Abol-Ftouh
- Department of Chemistry, Faculty of Science (Boys), Al-Azhar University, Nasr City, Cairo, Egypt,Mahmoud A. Abol-Ftouh Department of Chemistry, Faculty of Science (Boys), Al-Azhar University, Nasr City, Cairo11884, Egypt
| | - Ahmed A. Elhenawy
- Department of Chemistry, Faculty of Science (Boys), Al-Azhar University, Nasr City, Cairo, Egypt
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Decanoyl-Arg-Val-Lys-Arg-Chloromethylketone: An Antiviral Compound That Acts against Flaviviruses through the Inhibition of Furin-Mediated prM Cleavage. Viruses 2019; 11:v11111011. [PMID: 31683742 PMCID: PMC6893617 DOI: 10.3390/v11111011] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 10/24/2019] [Accepted: 10/30/2019] [Indexed: 01/04/2023] Open
Abstract
Flaviviruses, such as Zika virus (ZIKV), Japanese encephalitis virus (JEV), Dengue virus (DENV), and West Nile virus (WNV), are important arthropod-borne pathogens that present an immense global health problem. Their unpredictable disease severity, unusual clinical features, and severe neurological manifestations underscore an urgent need for antiviral interventions. Furin, a host proprotein convertase, is a key contender in processing flavivirus prM protein to M protein, turning the inert virus to an infectious particle. For this reason, the current study was planned to evaluate the antiviral activity of decanoyl-Arg-Val-Lys-Arg-chloromethylketone, a specific furin inhibitor, against flaviviruses, including ZIKV and JEV. Analysis of viral proteins revealed a significant increase in the prM/E index of ZIKV or JEV in dec-RVKR-cmk-treated Vero cells compared to DMSO-treated control cells, indicating dec-RVKR-cmk inhibits prM cleavage. Plaque assay, qRT-PCR, and immunofluorescence assay revealed a strong antiviral activity of dec-RVKR-cmk against ZIKV and JEV in terms of the reduction in virus progeny titer and in viral RNA and protein production in both mammalian cells and mosquito cells. Time-of-drug addition assay revealed that the maximum reduction of virus titer was observed in post-infection treatment. Furthermore, our results showed that dec-RVKR-cmk exerts its inhibitory action on the virus release and next round infectivity but not on viral RNA replication. Taken together, our study highlights an interesting antiviral activity of dec-RVKR-cmk against flaviviruses.
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5
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Izaguirre G. The Proteolytic Regulation of Virus Cell Entry by Furin and Other Proprotein Convertases. Viruses 2019; 11:v11090837. [PMID: 31505793 PMCID: PMC6784293 DOI: 10.3390/v11090837] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/03/2019] [Accepted: 09/06/2019] [Indexed: 12/11/2022] Open
Abstract
A wide variety of viruses exploit furin and other proprotein convertases (PCs) of the constitutive protein secretion pathway in order to regulate their cell entry mechanism and infectivity. Surface proteins of enveloped, as well as non-enveloped, viruses become processed by these proteases intracellularly during morphogenesis or extracellularly after egress and during entry in order to produce mature virions activated for infection. Although viruses also take advantage of other proteases, it is when some viruses become reactive with PCs that they may develop high pathogenicity. Besides reacting with furin, some viruses may also react with the PCs of the other specificity group constituted by PC4/PC5/PACE4/PC7. The targeting of PCs for inhibition may result in a useful strategy to treat infections with some highly pathogenic viruses. A wide variety of PC inhibitors have been developed and tested for their antiviral activity in cell-based assays.
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Affiliation(s)
- Gonzalo Izaguirre
- College of Dentistry, University of Illinois at Chicago, Chicago, IL 60612, USA.
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Yan L, Qu S, Liu G, Liu L, Yu Y, Ding G, Zhao Y, Li Y, Xie Y, Zhang J, Qu D. Comparative Transcriptomic Analysis of Primary Duck Hepatocytes Provides Insight into Differential Susceptibility to DHBV Infection. PLoS One 2016; 11:e0149702. [PMID: 26900848 PMCID: PMC4763071 DOI: 10.1371/journal.pone.0149702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 02/02/2016] [Indexed: 02/06/2023] Open
Abstract
Primary duck hepatocytes (PDH) displays differential susceptibility to duck hepatitis B virus when maintained in the media supplemented with fetal bovine serum or dimethyl sulfoxide (DMSO) which has been widely used for the maintenance of hepatocytes, and prolonging susceptibility to hepadnavirus. However the mechanism underlying maintenance of susceptibility to hepadnavirus by DMSO treatment remains unclear. In this study, a global transcriptome analysis of PDHs under different culture conditions was conducted for investigating the effects of DMSO on maintenance of susceptibility of PDH to DHBV in vitro. The 384 differential expressed genes (DEGs) were identified by comparisons between each library pair (PDHs cultured with or without DMSO or fresh isolated PDH). We analyzed canonical pathways in which the DEGs were enriched in Hepatic Fibrosis / Hepatic Stellate Cell Activation, Bile Acid Biosynthesis and Tight Junction signaling. After re-annotation against human genome data, the 384 DEGs were pooled together with proteins belonging to hepatitis B pathway to construct a protein-protein interaction network. The combination of decreased expression of liver-specific genes (CYP3A4, CYP1E1, CFI, RELN and GSTA1 et al) with increased expression of hepatocyte-dedifferentiation-associated genes (PLA2G4A and PLCG1) suggested that in vitro culture conditions results in the fading of hepatocyte phenotype in PDHs. The expression of seven DEGs associated with tight junction formation (JAM3, PPP2R2B, PRKAR1B, PPP2R2C, MAGI2, ACTA2 and ACTG2) was up-regulated after short-term culture in vitro, which was attenuated in the presence of DMSO. Those results could shed light on DHBV infection associated molecular events affected by DMSO.
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Affiliation(s)
- Liang Yan
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Su Qu
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, China
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Gang Liu
- Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lei Liu
- Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yao Yu
- Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Guohui Ding
- Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yanfeng Zhao
- Department of Laboratory Medicine, the Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yixue Li
- Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Youhua Xie
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, China
- * E-mail: (DQ); (JZ); (YX)
| | - Junqi Zhang
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, China
- * E-mail: (DQ); (JZ); (YX)
| | - Di Qu
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, China
- * E-mail: (DQ); (JZ); (YX)
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Li J, Tong S. From DCPD to NTCP: the long journey towards identifying a functional hepatitis B virus receptor. Clin Mol Hepatol 2015; 21:193-9. [PMID: 26523264 PMCID: PMC4612279 DOI: 10.3350/cmh.2015.21.3.193] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 08/15/2015] [Indexed: 12/13/2022] Open
Abstract
Hepatitis B virus (HBV) is the prototype of hepatotropic DNA viruses (hepadnaviruses) infecting a wide range of human and non-human hosts. Previous studies with duck hepatitis B virus (DHBV) identified duck carboxypeptidase D (dCPD) as a host specific binding partner for full-length large envelope protein, and p120 as a binding partner for several truncated versions of the large envelope protein. p120 is the P protein of duck glycine decarboxylase (dGLDC) with restricted expression in DHBV infectible tissues. Several lines of evidence suggest the importance of dCPD, and especially p120, in productive DHBV infection, although neither dCPD nor p120 cDNA could confer susceptibility to DHBV infection in any cell line. Recently, sodium taurocholate cotransporting polypeptide (NTCP) has been identified as a binding partner for the N-terminus of HBV large envelope protein. Importantly, knock down and reconstitution experiments unequivocally demonstrated that NTCP is both necessary and sufficient for in vitro infection by HBV and hepatitis delta virus (HDV), an RNA virus using HBV envelope proteins for its transmission. What remains unclear is whether NTCP is the major HBV receptor in vivo. The fact that some HBV patients are homozygous with an NTCP mutation known to abolish its receptor function suggests the existence of NTCP-independent pathways of HBV entry. Also, NTCP very likely mediates just one step of the HBV entry process, with additional co-factors for productive HBV infection still to be discovered. NTCP offers a novel therapeutic target for the control of chronic HBV infection.
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Affiliation(s)
- Jisu Li
- Liver Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, USA
| | - Shuping Tong
- Liver Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, USA. ; Key lab of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
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Nucleic acid polymers inhibit duck hepatitis B virus infection in vitro. Antimicrob Agents Chemother 2013; 57:5291-8. [PMID: 23939902 DOI: 10.1128/aac.01003-13] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Nucleic acid polymers (NAPs) utilize the sequence-independent properties of phosphorothioate oligonucleotides (PS-ONs) to target protein interactions involved in viral replication. NAPs are broadly active against a diverse range of enveloped viruses that use type I entry mechanisms. The antiviral activity of NAPs against hepatitis B virus (HBV) infection was assessed in vitro in duck hepatitis B virus (DHBV)-infected primary duck hepatocytes (PDH). NAPs efficiently entered PDH in the absence of any transfection agent and displayed antiviral activity at concentrations of 0.01 to 10 μM, measured by their ability to prevent the intracellular accumulation of DHBV surface antigen, which was independent of their nucleotide sequence and was specifically dependent on phosphorothioation. Higher levels of antiviral activity were observed with NAPs 40 nucleotides in length or longer. The fully degenerate NAP (REP 2006) was active during DHBV infection or when added 12 h after infection. In contrast, an acidic-pH-sensitive NAP (REP 2031) that was broadly active against other viruses displayed antiviral activity when present during DHBV infection but no activity when added 12 h after infection, suggesting that NAPs exert their postentry effect in an acidic environment unique to DHBV infection. Both REP 2006 and REP 2031 displayed negligible cytotoxicity in PDH at concentrations of up to 10 μM, as assessed using an XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] cytotoxicity assay. The antiviral activity of NAPs against DHBV in vitro was strictly dependent on their amphipathic character, suggesting that NAPs interact with amphipathic target(s) that are important for DHBV entry and postentry mechanisms required for infection.
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Zhang L, Katselis GS, Moore RE, Lekpor K, Goto RM, Lee TD, Miller MM. Proteomic Analysis of Surface and Endosomal Membrane Proteins from the Avian LMH Epithelial Cell Line. J Proteome Res 2011; 10:3973-82. [DOI: 10.1021/pr200179r] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lei Zhang
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
| | - George S. Katselis
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
| | - Roger E. Moore
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
| | - Kossi Lekpor
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
| | - Ronald M. Goto
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
| | - Terry D. Lee
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
| | - Marcia M. Miller
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
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Solution structure of a repeated unit of the ABA-1 nematode polyprotein allergen of Ascaris reveals a novel fold and two discrete lipid-binding sites. PLoS Negl Trop Dis 2011; 5:e1040. [PMID: 21526216 PMCID: PMC3079579 DOI: 10.1371/journal.pntd.0001040] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 03/18/2011] [Indexed: 01/12/2023] Open
Abstract
Background Nematode polyprotein allergens (NPAs) are an unusual class of lipid-binding proteins found only in nematodes. They are synthesized as large, tandemly repetitive polyproteins that are post-translationally cleaved into multiple copies of small lipid binding proteins with virtually identical fatty acid and retinol (Vitamin A)-binding characteristics. They are probably central to transport and distribution of small hydrophobic compounds between the tissues of nematodes, and may play key roles in nutrient scavenging, immunomodulation, and IgE antibody-based responses in infection. In some species the repeating units are diverse in amino acid sequence, but, in ascarid and filarial nematodes, many of the units are identical or near-identical. ABA-1A is the most common repeating unit of the NPA of Ascaris suum, and is closely similar to that of Ascaris lumbricoides, the large intestinal roundworm of humans. Immune responses to NPAs have been associated with naturally-acquired resistance to infection in humans, and the immune repertoire to them is under strict genetic control. Methodology/Principal Findings The solution structure of ABA-1A was determined by protein nuclear magnetic resonance spectroscopy. The protein adopts a novel seven-helical fold comprising a long central helix that participates in two hollow four-helical bundles on either side. Discrete hydrophobic ligand-binding pockets are found in the N-terminal and C-terminal bundles, and the amino acid sidechains affected by ligand (fatty acid) binding were identified. Recombinant ABA-1A contains tightly-bound ligand(s) of bacterial culture origin in one of its binding sites. Conclusions/Significance This is the first mature, post-translationally processed, unit of a naturally-occurring tandemly-repetitive polyprotein to be structurally characterized from any source, and it belongs to a new structural class. NPAs have no counterparts in vertebrates, so represent potential targets for drug or immunological intervention. The nature of the (as yet) unidentified bacterial ligand(s) may be pertinent to this, as will our characterization of the unusual binding sites. Parasitic nematode worms cause serious health problems in humans and other animals. They can induce allergic-type immune responses, which can be harmful but may at the same time protect against the infections. Allergens are proteins that trigger allergic reactions and these parasites produce a type that is confined to nematodes, the nematode polyprotein allergens (NPAs). These are synthesized as large precursor proteins comprising repeating units of similar amino acid sequence that are subsequently cleaved into multiple copies of the allergen protein. NPAs bind small lipids such as fatty acids and retinol (Vitamin A) and probably transport these sensitive and insoluble compounds between the tissues of the worms. Nematodes cannot synthesize these lipids, so NPAs may also be crucial for extracting nutrients from their hosts. They may also be involved in altering immune responses by controlling the lipids by which the immune and inflammatory cells communicate. We describe the molecular structure of one unit of an NPA, the well-known ABA-1 allergen of Ascaris, and find its structure to be of a type not previously found for lipid-binding proteins, and we describe the unusual sites where lipids bind within this structure.
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