The Experts below are selected from a list of 525207 Experts worldwide ranked by ideXlab platform
Ting Ye - One of the best experts on this subject based on the ideXlab platform.
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tachypleus tridentatus lectin enhances oncolytic vaccinia virus replication to suppress in vivo hepatocellular carcinoma growth
Marine Drugs, 2018Co-Authors: Gongchu Li, Jianhong Cheng, Tao Wu, Ting YeAbstract:Lectins play diverse roles in physiological processes as biological recognition molecules. In this report, a gene encoding Tachypleus tridentatus Lectin (TTL) was inserted into an oncolytic vaccinia virus (oncoVV) vector to form oncoVV-TTL, which showed significant antitumor activity in a hepatocellular carcinoma mouse model. Furthermore, TTL enhanced oncoVV replication through suppressing antiviral factors expression such as interferon-inducible Protein 16 (IFI16), mitochondrial antiviral Signaling Protein (MAVS) and interferon-beta (IFN-β). Further investigations revealed that oncoVV-TTL replication was highly dependent on ERK activity. This study might provide insights into a novel way of the utilization of TTL in oncolytic viral therapies.
Thorsten Wohland - One of the best experts on this subject based on the ideXlab platform.
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The Secreted Signaling Protein Wnt3 Is Associated with Membrane Domains In Vivo: A SPIM-FCS Study
Biophysical journal, 2016Co-Authors: Cathleen Teh, Vladimir Korzh, Thorsten WohlandAbstract:Wnt3 is a morphogen that activates the Wnt Signaling pathway and regulates a multitude of biological processes ranging from cell proliferation and cell fate specification to differentiation over embryonic induction to neural patterning. Recent studies have shown that the palmitoylation of Wnt3 by Porcupine, a membrane-bound O-acyltransferase, plays a significant role in the intracellular membrane trafficking of Wnt3 and subsequently, its secretion in live zebrafish embryos, where chemical inhibition of Porcupine reduced the membrane-bound and secreted fractions of Wnt3 and eventually led to defective brain development. However, the membrane distribution of Wnt3 in cells remains not fully understood. Here, we determine the membrane organization of functionally active Wnt3-EGFP in cerebellar cells of live transgenic zebrafish embryos and the role of palmitoylation in its organization using single plane illumination microscopy-fluorescence correlation spectroscopy (SPIM-FCS), a multiplexed modality of FCS, which generates maps of molecular dynamics, concentration, and interaction of biomolecules. The FCS diffusion law was applied to SPIM-FCS data to study the subresolution membrane organization of Wnt3. We find that at the plasma membrane in vivo, Wnt3 is associated with cholesterol-dependent domains. This association reduces with increasing concentrations of Porcupine inhibitor (C59), confirming the importance of palmitoylation of Wnt3 for its association with cholesterol-dependent domains. Reduction of membrane cholesterol also results in a decrease of Wnt3 association with cholesterol-dependent domains in live zebrafish. This demonstrates for the first time, to our knowledge, in live vertebrate embryos that Wnt3 is associated with cholesterol-dependent domains.
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The Secreted Signaling Protein Wnt3 Resides in Plasma Membrane Lipid Domains in Vivo: A SPIM-FCS Study
Biophysical Journal, 2016Co-Authors: Thorsten Wohland, Cathleen Teh, Vladimir KorzhAbstract:Wnt3 is a Signaling Protein involved in development and disease (oncogenesis and tetraamelia syndrome). Recently, we have shown that Wnt3 regulates cerebellum development using zebrafish Wnt3 transgenics with either tissue-specific expression of an EGFP reporter or a functionally active fusion Protein, Wnt3EGFP (Teh et al., Development 2015). We identified several fractions of Wnt3: i) an intracellular and ii) a secreted fraction, which comprises of monomeric Wnt3 as well as its complexes, and, iii) a membrane-bound fraction. The membrane-bound O-acyltransferase Porcupine is required for Wnt palmitoylation, secretion and biological activity. It was shown in vitro that for membrane localization in Wnt3-expressing cells Wnt3 undergoes two lipid modifications by palmitoylation at C77 and S209. Such posttranslational modifications have been linked with Protein association with cholesterol-dependent lipid domains. This raises the question whether Wnt3 is targeted to these domains in live zebrafish. We therefore used SPIM-FCS and the FCS diffusion laws, which characterize the dependence of the diffusion coefficient on the observed area to deduce deviations from free diffusion, to characterize Wnt3 distribution on plasma membranes in zebrafish embryos.First, we demonstrate that the diffusion laws can be applied in a 3D environment of SPIM-FCS by characterizing lipid distributions in giant unilamellar vesicles (GUVs) of various compositions. Second, we applied this methodology to analyze Wnt3 distribution on plasma membranes in live Wnt3 transgenic embryos. This demonstrated that in vivo the Wnt3 membrane-bound fraction also shows consistent raft partitioning. Third, upon reduction of Wnt3 secretion by a specific inhibitor of Porcupine, Wnt3 partitioning into lipid domains is also reduced. Taken together this demonstrates that in developing zebrafish embryos the plasma membrane fraction of Wnt3 to be secreted needs to be compartmentalized into specialized lipid domains.
Vladimir Korzh - One of the best experts on this subject based on the ideXlab platform.
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The Secreted Signaling Protein Wnt3 Is Associated with Membrane Domains In Vivo: A SPIM-FCS Study
Biophysical journal, 2016Co-Authors: Cathleen Teh, Vladimir Korzh, Thorsten WohlandAbstract:Wnt3 is a morphogen that activates the Wnt Signaling pathway and regulates a multitude of biological processes ranging from cell proliferation and cell fate specification to differentiation over embryonic induction to neural patterning. Recent studies have shown that the palmitoylation of Wnt3 by Porcupine, a membrane-bound O-acyltransferase, plays a significant role in the intracellular membrane trafficking of Wnt3 and subsequently, its secretion in live zebrafish embryos, where chemical inhibition of Porcupine reduced the membrane-bound and secreted fractions of Wnt3 and eventually led to defective brain development. However, the membrane distribution of Wnt3 in cells remains not fully understood. Here, we determine the membrane organization of functionally active Wnt3-EGFP in cerebellar cells of live transgenic zebrafish embryos and the role of palmitoylation in its organization using single plane illumination microscopy-fluorescence correlation spectroscopy (SPIM-FCS), a multiplexed modality of FCS, which generates maps of molecular dynamics, concentration, and interaction of biomolecules. The FCS diffusion law was applied to SPIM-FCS data to study the subresolution membrane organization of Wnt3. We find that at the plasma membrane in vivo, Wnt3 is associated with cholesterol-dependent domains. This association reduces with increasing concentrations of Porcupine inhibitor (C59), confirming the importance of palmitoylation of Wnt3 for its association with cholesterol-dependent domains. Reduction of membrane cholesterol also results in a decrease of Wnt3 association with cholesterol-dependent domains in live zebrafish. This demonstrates for the first time, to our knowledge, in live vertebrate embryos that Wnt3 is associated with cholesterol-dependent domains.
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The Secreted Signaling Protein Wnt3 Resides in Plasma Membrane Lipid Domains in Vivo: A SPIM-FCS Study
Biophysical Journal, 2016Co-Authors: Thorsten Wohland, Cathleen Teh, Vladimir KorzhAbstract:Wnt3 is a Signaling Protein involved in development and disease (oncogenesis and tetraamelia syndrome). Recently, we have shown that Wnt3 regulates cerebellum development using zebrafish Wnt3 transgenics with either tissue-specific expression of an EGFP reporter or a functionally active fusion Protein, Wnt3EGFP (Teh et al., Development 2015). We identified several fractions of Wnt3: i) an intracellular and ii) a secreted fraction, which comprises of monomeric Wnt3 as well as its complexes, and, iii) a membrane-bound fraction. The membrane-bound O-acyltransferase Porcupine is required for Wnt palmitoylation, secretion and biological activity. It was shown in vitro that for membrane localization in Wnt3-expressing cells Wnt3 undergoes two lipid modifications by palmitoylation at C77 and S209. Such posttranslational modifications have been linked with Protein association with cholesterol-dependent lipid domains. This raises the question whether Wnt3 is targeted to these domains in live zebrafish. We therefore used SPIM-FCS and the FCS diffusion laws, which characterize the dependence of the diffusion coefficient on the observed area to deduce deviations from free diffusion, to characterize Wnt3 distribution on plasma membranes in zebrafish embryos.First, we demonstrate that the diffusion laws can be applied in a 3D environment of SPIM-FCS by characterizing lipid distributions in giant unilamellar vesicles (GUVs) of various compositions. Second, we applied this methodology to analyze Wnt3 distribution on plasma membranes in live Wnt3 transgenic embryos. This demonstrated that in vivo the Wnt3 membrane-bound fraction also shows consistent raft partitioning. Third, upon reduction of Wnt3 secretion by a specific inhibitor of Porcupine, Wnt3 partitioning into lipid domains is also reduced. Taken together this demonstrates that in developing zebrafish embryos the plasma membrane fraction of Wnt3 to be secreted needs to be compartmentalized into specialized lipid domains.
Zhijian J Chen - One of the best experts on this subject based on the ideXlab platform.
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cyclic di gmp sensing via the innate immune Signaling Protein sting
Molecular Cell, 2012Co-Authors: Qian Yin, Yuan Tian, Venkataraman Kabaleeswaran, Xiaomo Jiang, Michael J Eck, Zhijian J ChenAbstract:Detection of foreign materials is the first step of successful immune responses. Stimulator of interferon genes (STING) was shown to directly bind cyclic diguanylate monophosphate (c-di-GMP), a bacterial second messenger, and to elicit strong interferon responses. Here we elucidate the structural features of the cytosolic c-di-GMP binding domain (CBD) of STING and its complex with c-di-GMP. The CBD exhibits an α + β fold and is a dimer in the crystal and in solution. Surprisingly, one c-di-GMP molecule binds to the central crevice of a STING dimer, using a series of stacking and hydrogen bonding interactions. We show that STING is autoinhibited by an intramolecular interaction between the CBD and the C-terminal tail (CTT) and that c-di-GMP releases STING from this autoinhibition by displacing the CTT. The structures provide a remarkable example of pathogen-host interactions in which a unique microbial molecule directly engages the innate immune system.
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mitochondrial antiviral Signaling Protein mavs monitors commensal bacteria and induces an immune response that prevents experimental colitis
Proceedings of the National Academy of Sciences of the United States of America, 2011Co-Authors: Xiao Dong Li, Yu Hsin Chiu, Anisa S Ismail, Cassie L Behrendt, Mary Wightcarter, Lora V Hooper, Zhijian J ChenAbstract:RIG-I–like receptors (RLRs) activate host innate immune responses against virus infection through recruiting the mitochondrial adaptor Protein MAVS (also known as IPS1, VISA, or CARDIF). Here we show that MAVS also plays a pivotal role in maintaining intestinal homeostasis. We found that MAVS knockout mice developed more severe mortality and morbidity than WT animals in an experimental model of colitis. Bone marrow transplantation experiments revealed that MAVS in cells of nonhematopoietic origin plays a dominant role in the protection against colitis. Importantly, RNA species derived from intestinal commensal bacteria activate the RIG-I–MAVS pathway to induce the production of multiple cytokines and antimicrobial peptides, including IFN-β and RegIIIγ. These results unveil a previously unexplored role of MAVS in monitoring intestinal commensal bacteria and maintaining tissue homeostasis.
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vaccinia virus subverts a mitochondrial antiviral Signaling Protein dependent innate immune response in keratinocytes through its double stranded rna binding Protein e3
Journal of Virology, 2008Co-Authors: Liang Deng, Zhijian J Chen, Tanvi Parikh, Vijay G Bhoj, Taha Merghoub, Alan N Houghton, Stewart ShumanAbstract:Skin keratinocytes provide a first line of defense against invading microorganisms in two ways: (i) by acting as a physical barrier to pathogen entry and (ii) by initiating a vigorous innate immune response upon sensing danger signals. How keratinocytes detect virus infections and generate antiviral immune responses is not well understood. Orthopoxviruses are dermatotropic DNA viruses that cause lethal disease in humans. Virulence in animal models depends on the virus-encoded bifunctional Z-DNA/double-stranded RNA (dsRNA)-binding Protein E3. Here, we report that infection of mouse primary keratinocytes with a vaccinia ΔE3L mutant virus triggers the production of beta interferon (IFN-β), interleukin-6 (IL-6), CCL4, and CCL5. None of these immune mediators is produced by keratinocytes infected with wild-type vaccinia virus. The dsRNA-binding domain of E3 suffices to prevent activation of the innate immune response. ΔE3L induction of IFN-β, IL-6, CCL4, and CCL5 secretion requires mitochondrial antiviral Signaling Protein (MAVS; an adaptor for the cytoplasmic viral RNA sensors RIG-I and MDA5) and the transcription factor IRF3. IRF3 phosphorylation is induced in keratinocytes infected with ΔE3L, an event that depends on MAVS. The response of keratinocytes to ΔE3L is unaffected by genetic ablation of Toll-like receptor 3 (TLR3), TRIF, TLR9, and MyD88.
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type i interferon production during herpes simplex virus infection is controlled by cell type specific viral recognition through toll like receptor 9 the mitochondrial antiviral Signaling Protein pathway and novel recognition systems
Journal of Virology, 2007Co-Authors: Simon B Rasmussen, Zhijian J Chen, Louise N Sorensen, Lene Malmgaard, Joel D Baines, Soren R PaludanAbstract:Recognition of viruses by germ line-encoded pattern recognition receptors of the innate immune system is essential for rapid production of type I interferon (IFN) and early antiviral defense. We investigated the mechanisms of viral recognition governing production of type I IFN during herpes simplex virus (HSV) infection. We show that early production of IFN in vivo is mediated through Toll-like receptor 9 (TLR9) and plasmacytoid dendritic cells, whereas the subsequent alpha/beta IFN (IFN-α/β) response is derived from several cell types and induced independently of TLR9. In conventional DCs, the IFN response occurred independently of viral replication but was dependent on viral entry. Moreover, using a HSV-1 UL15 mutant, which fails to package viral DNA into the virion, we found that entry-dependent IFN induction also required the presence of viral genomic DNA. In macrophages and fibroblasts, where the virus was able to replicate, HSV-induced IFN-α/β production was dependent on both viral entry and replication, and ablated in cells unable to signal through the mitochondrial antiviral Signaling Protein pathway. Thus, during an HSV infection in vivo, multiple mechanisms of pathogen recognition are active, which operate in cell-type- and time-dependent manners to trigger expression of type I IFN and coordinate the antiviral response.
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hepatitis c virus protease ns3 4a cleaves mitochondrial antiviral Signaling Protein off the mitochondria to evade innate immunity
Proceedings of the National Academy of Sciences of the United States of America, 2005Co-Authors: Xiao Dong Li, Rashu B Seth, Gabriel Pineda, Zhijian J ChenAbstract:Hepatitis C virus (HCV) is a global epidemic manifested mainly by chronic infection. One strategy that HCV employs to establish chronic infection is to use the viral Ser protease NS3/4A to cleave some unknown cellular targets involved in innate immunity. Here we show that the target of NS3/4A is the mitochondrial antiviral Signaling Protein, MAVS, that activates NF-κB and IFN regulatory factor 3 to induce type-I interferons. NS3/4A cleaves MAVS at Cys-508, resulting in the dislocation of the N-terminal fragment of MAVS from the mitochondria. Remarkably, a point mutation of MAVS at Cys-508 renders MAVS resistant to cleavage by NS3/4A, thus maintaining the ability of MAVS to induce interferons in HCV replicon cells. NS3/4A binds to and colocalizes with MAVS in the mitochondrial membrane, and it can cleave MAVS directly in vitro. These results provide an example of host–pathogen interaction in which the virus evades innate immunity by dislodging a pivotal antiviral Protein from the mitochondria and suggest that blocking the cleavage of MAVS by NS3/4A may be applied to the prevention and treatment of HCV.
Gongchu Li - One of the best experts on this subject based on the ideXlab platform.
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tachypleus tridentatus lectin enhances oncolytic vaccinia virus replication to suppress in vivo hepatocellular carcinoma growth
Marine Drugs, 2018Co-Authors: Gongchu Li, Jianhong Cheng, Tao Wu, Ting YeAbstract:Lectins play diverse roles in physiological processes as biological recognition molecules. In this report, a gene encoding Tachypleus tridentatus Lectin (TTL) was inserted into an oncolytic vaccinia virus (oncoVV) vector to form oncoVV-TTL, which showed significant antitumor activity in a hepatocellular carcinoma mouse model. Furthermore, TTL enhanced oncoVV replication through suppressing antiviral factors expression such as interferon-inducible Protein 16 (IFI16), mitochondrial antiviral Signaling Protein (MAVS) and interferon-beta (IFN-β). Further investigations revealed that oncoVV-TTL replication was highly dependent on ERK activity. This study might provide insights into a novel way of the utilization of TTL in oncolytic viral therapies.
