13 results on '"Dong, A-liang"'
Search Results
2. ShDcR3 sensitizes TRAIL-resistant HCC cells by inducing caspase-dependent apoptosis while suppressing NF-κB dependent cFLIPL expression.
- Author
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Dong-Yu Liang, Wei Huang, Qing Chang, and Yan-Qiang Hou
- Subjects
Medicine ,Science - Abstract
Evidence has shown that most hepatocellular carcinoma (HCC) cells are resistant to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. However, the molecular mechanisms underlying TRAIL-mediated apoptosis resistance are not well understood. In this study, we reported that downregulation of Decoy receptor 3 (DcR3) expression by lentiviral vectors carrying shRNA against DcR3 (LV-ShDcR3, shDcR3) in Huh7 both greatly enhanced TRAIL-mediated apoptosis and reduced cell proliferation capability. In addition, silencing DcR3 resulted in upregulation of the cell apoptotic regulators including Bid, caspase-3, and caspase-8. Caspase inhibitors inhibited shDcR3-mediated cell death, which indicated that downregulation of DcR3 expression in Huh7 cells increased TRAIL-induced caspase-dependent apoptotic cell death. Furthermore, although the knockdown of DcR3 altered the expression of some Bcl-2- and IAP-family proteins, this change was inhibited by pretreatment with a pancaspase inhibitor, which indicated the cytotoxic effect of shDcR3 was not due to the expression of these proteins. In contrast, shDcR3 significantly inhibited TRAIL-induced transcription factor nuclear κB (NF-κB) activation through the IκB kinase (IKK) pathway, as well as inhibited TRAIL-induced increases in FLICE-inhibitory protein long form (cFLIPL) expression at the transcriptional level. Silencing cFLIPL expression mimicked the cytotoxic effect of shDcR3 on TRAIL-mediated cell apoptosis. Moreover, overexpression of cFLIPL effectively prevented the increase in cell apoptosis in Huh7 cells co-treated with TRAIL and shDcR3. Taken together, our findings indicated that silencing DcR3 sensitizes TRAIL-mediated apoptosis in HCC cells by inhibiting NF-κB.
- Published
- 2018
- Full Text
- View/download PDF
3. The UII/UT system mediates upregulation of proinflammatory cytokines through p38 MAPK and NF-κB pathways in LPS-stimulated Kupffer cells.
- Author
-
Liang Ming Liu, Dong Yu Liang, Chang Gen Ye, Wen Juan Tu, and Tong Zhu
- Subjects
Medicine ,Science - Abstract
The urotensin II (UII)/UII receptor (UT) system is closely related to immune inflammation. In acute liver failure (ALF), the UII/UT system can promote the production and release of proinflammatory cytokines, inducing an inflammatory injury response in liver tissue. However, the mechanism by which the hepatic UII/UT system promotes proinflammatory cytokine production and release is not clear. To solve this problem, we used primary Kupffer cells (KCs) as the model system in the current study. The results showed that after lipopolysaccharide (LPS) stimulation, KCs showed significantly increased expression and release of UII/UT and proinflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β). Pretreatment with urantide, which is a UT receptor antagonist, significantly inhibited the LPS-stimulated expression and release of UII/UT, TNF-α, and IL-1β by KCs. In addition, LPS stimulation induced nuclear p38 mitogen-activated protein kinase (MAPK) protein phosphorylation and expression of the nuclear nuclear factor κB (NF-κB) p65 subunit in KCs and enhanced the binding activity of NF-κB to DNA molecules, whereas urantide pretreatment significantly inhibited the LPS-stimulated nuclear expression and activity of these molecules in KCs. Therefore, our conclusion is that the UII/UT system mediates LPS-stimulated production and release of proinflammatory cytokine by KCs, and this mediating effect at least partially relies on the inflammatory signaling pathway molecules p38 MAPK and NF-κB.
- Published
- 2015
- Full Text
- View/download PDF
4. Inhibition of UII/UTR system relieves acute inflammation of liver through preventing activation of NF-κB pathway in ALF mice.
- Author
-
Dong-yu Liang, Liang-ming Liu, Chang-gen Ye, Liang Zhao, Fang-ping Yu, De-yong Gao, Ying-ying Wang, Zhi-wen Yang, and Yan-yan Wang
- Subjects
Medicine ,Science - Abstract
Urotensin II (UII) is implicated in immune inflammatory diseases through its specific high-affinity UT receptor (UTR). Enhanced expression of UII/UTR was recently demonstrated in the liver with acute liver failure (ALF). Here, we analysed the relationship between UII/UTR expression and ALF in lipopolysaccharide (LPS)/D-galactosamine (GalN)-challenged mice. Thereafter, we investigated the effects produced by the inhibition of UII/UTR system using urantide, a special antagonist of UTR, and the potential molecular mechanisms involved in ALF. Urantide was administered to mice treated with LPS/GalN. Expression of UII/UTR, releases of proinflammatory cytokines including tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and interferon-γ (IFN-γ), and activation of nuclear factor κB (NF-κB) signaling pathway were assessed in the lethal ALF with or without urantide pretreatment. We found that LPS/GalN-challenged mice showed high mortality and marked hepatic inflammatory infiltration and cell apoptosis as well as a significant increase of UII/UTR expression. Urantide pretreatment protected against the injury in liver following downregulation of UII/UTR expression. A close relationship between the acutely flamed hepatic injury and UII/UTR expression was observed. In addition, urantide prevented the increases of proinflammatory cytokines such as TNF-α, IL-1β and IFN-γ, and activation of NF-κB signaling pathway induced by LPS/GalN in mice. Thus, we conclude that UII/UTR system plays a role in LPS/GalN-induced ALF. Urantide has a protective effect on the acutely inflamed injury of liver in part through preventing releases of proinflammatory cytokines and activation of NF-κB pathway.
- Published
- 2014
- Full Text
- View/download PDF
5. GSP-2, a polysaccharide extracted from Ganoderma sinense, is a novel toll-like receptor 4 agonist
- Author
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Liu, Kai-Sheng, primary, Zhang, Cheng, additional, Dong, Hong-Liang, additional, Li, Kai-Kai, additional, Han, Quan-Bin, additional, Wan, Yong, additional, Chen, Rui, additional, Yang, Fang, additional, Li, Hai-Li, additional, Ko, Chun-Hay, additional, and Han, Xiao-Qiang, additional
- Published
- 2019
- Full Text
- View/download PDF
6. ShDcR3 sensitizes TRAIL-resistant HCC cells by inducing caspase-dependent apoptosis while suppressing NF-κB dependent cFLIPL expression
- Author
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Qing Chang, Wei Huang, Dong-Yu Liang, and Yanqiang Hou
- Subjects
0301 basic medicine ,Transcription, Genetic ,Protein Expression ,CASP8 and FADD-Like Apoptosis Regulating Protein ,lcsh:Medicine ,Apoptosis ,IκB kinase ,Biochemistry ,TNF-Related Apoptosis-Inducing Ligand ,0302 clinical medicine ,Cell Signaling ,Medicine and Health Sciences ,Cytotoxic T cell ,Small interfering RNAs ,Post-Translational Modification ,Phosphorylation ,lcsh:Science ,Apoptotic Signaling Cascade ,Multidisciplinary ,Cell Death ,Protein Kinase Signaling Cascade ,Chemistry ,Liver Diseases ,Liver Neoplasms ,NF-kappa B ,Signaling Cascades ,Nucleic acids ,Oncology ,Cell Processes ,Caspases ,030220 oncology & carcinogenesis ,Hyperexpression Techniques ,Research Article ,Signal Transduction ,Programmed cell death ,Carcinoma, Hepatocellular ,Down-Regulation ,Gastroenterology and Hepatology ,Research and Analysis Methods ,Carcinomas ,Caspase-Dependent Apoptosis ,03 medical and health sciences ,Downregulation and upregulation ,Cell Line, Tumor ,Gastrointestinal Tumors ,Gene Expression and Vector Techniques ,Genetics ,Humans ,Molecular Biology Techniques ,Non-coding RNA ,Molecular Biology ,Molecular Biology Assays and Analysis Techniques ,Cell growth ,Receptors, Tumor Necrosis Factor, Member 6b ,lcsh:R ,Biology and Life Sciences ,Cancers and Neoplasms ,Proteins ,Cell Biology ,Hepatocellular Carcinoma ,Gene regulation ,030104 developmental biology ,Cancer research ,RNA ,lcsh:Q ,Gene expression ,Decoy receptor 3 - Abstract
Evidence has shown that most hepatocellular carcinoma (HCC) cells are resistant to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. However, the molecular mechanisms underlying TRAIL-mediated apoptosis resistance are not well understood. In this study, we reported that downregulation of Decoy receptor 3 (DcR3) expression by lentiviral vectors carrying shRNA against DcR3 (LV-ShDcR3, shDcR3) in Huh7 both greatly enhanced TRAIL-mediated apoptosis and reduced cell proliferation capability. In addition, silencing DcR3 resulted in upregulation of the cell apoptotic regulators including Bid, caspase-3, and caspase-8. Caspase inhibitors inhibited shDcR3-mediated cell death, which indicated that downregulation of DcR3 expression in Huh7 cells increased TRAIL-induced caspase-dependent apoptotic cell death. Furthermore, although the knockdown of DcR3 altered the expression of some Bcl-2- and IAP-family proteins, this change was inhibited by pretreatment with a pancaspase inhibitor, which indicated the cytotoxic effect of shDcR3 was not due to the expression of these proteins. In contrast, shDcR3 significantly inhibited TRAIL-induced transcription factor nuclear κB (NF-κB) activation through the IκB kinase (IKK) pathway, as well as inhibited TRAIL-induced increases in FLICE-inhibitory protein long form (cFLIPL) expression at the transcriptional level. Silencing cFLIPL expression mimicked the cytotoxic effect of shDcR3 on TRAIL-mediated cell apoptosis. Moreover, overexpression of cFLIPL effectively prevented the increase in cell apoptosis in Huh7 cells co-treated with TRAIL and shDcR3. Taken together, our findings indicated that silencing DcR3 sensitizes TRAIL-mediated apoptosis in HCC cells by inhibiting NF-κB.
- Published
- 2018
7. Decoy Receptor 3 Improves Survival in Experimental Sepsis by Suppressing the Inflammatory Response and Lymphocyte Apoptosis
- Author
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Xiaoli Lou, Yanqiang Hou, Dong-Yu Liang, and Hongwei Chen
- Subjects
Fas Ligand Protein ,medicine.medical_treatment ,lcsh:Medicine ,Spleen ,Apoptosis ,Thymus Gland ,Biology ,Sepsis ,Mice ,medicine ,Animals ,Lymphocytes ,lcsh:Science ,Lung ,Multidisciplinary ,Receptors, Tumor Necrosis Factor, Member 6b ,lcsh:R ,medicine.disease ,In vitro ,Disease Models, Animal ,Cytokine ,medicine.anatomical_structure ,Liver ,Decreased lymphocyte apoptosis ,Immunology ,Cytokines ,lcsh:Q ,Decoy receptor 3 ,Research Article - Abstract
Purpose Unbalanced inflammatory response and lymphocyte apoptosis is associated with high mortality in septic patients. Decoy receptor 3 (DcR3), a member of the tumor necrosis factor receptor superfamily, is an anti-inflammatory and anti-apoptotic factor. Recently, DcR3 expression was found to be increased in septic patients. This study evaluated the therapeutic effect and mechanisms of DcR3 on cecal ligation and puncture (CLP)-induced sepsis in mice. Methods C57BL/6 mice were subjected to CLP-induced polymicrobial sepsis. DcR3 Fc was intravenously injected 30 min before and 6 h after CLP. Bacterial clearance, cytokine production, histology, lymphocyte apoptosis and survival were evaluated. Furthermore, we investigated the systemic effects of DcR3 in in vitro lymphocyte apoptosis regulation. Results Our results demonstrated that DcR3 protein treatments significantly improved survival in septic mice (p
- Published
- 2015
8. Deoxyhypusine Hydroxylase from Plasmodium vivax, the Neglected Human Malaria Parasite: Molecular Cloning, Expression and Specific Inhibition by the 5-LOX Inhibitor Zileuton
- Author
-
Atemnkeng, Veronika Anyigoh, Pink, Mario, Schmitz-Spanke, Simone, Wu, Xian-Jun, Dong, Liang-Liang, Zhao, Kai-Hong, May, Caroline, Laufer, Stefan, Langer, Barbara, and Kaiser, Annette
- Subjects
Drugs and Devices ,Drug Research and Development ,Transcription, Genetic ,Molecular Sequence Data ,Medizin ,lcsh:Medicine ,Gene Expression ,Pathogenesis ,Biochemistry ,Microbiology ,Mixed Function Oxygenases ,parasitic diseases ,Drug Discovery ,Parasitic Diseases ,Malaria, Vivax ,Animals ,Cluster Analysis ,Humans ,Hydroxyurea ,Plasmodium Vivax ,ddc:610 ,Amino Acid Sequence ,Lipoxygenase Inhibitors ,Parasite Evolution ,Cloning, Molecular ,lcsh:Science ,Biology ,ddc:615 ,Arachidonate 5-Lipoxygenase ,lcsh:R ,Phycocyanin ,Malaria ,Enzyme Activation ,Infectious Diseases ,Medizinische Fakultät » Universitätsklinikum Essen » Institut für Pharmakogenetik ,Medical Microbiology ,Medicine ,lcsh:Q ,Parasitology ,Sequence Alignment ,Research Article ,Biotechnology - Abstract
Primaquine, an 8-aminoquinoline, is the only drug which cures the dormant hypnozoites of persistent liver stages from P. vivax. Increasing resistance needs the discovery of alternative pathways as drug targets to develop novel drug entities. Deoxyhypusine hydroxylase (DOHH) completes hypusine biosynthesis in eukaryotic initiation factor (eIF-5A) which is the only cellular protein known to contain the unusual amino acid hypusine. Modified EIF-5A is important for proliferation of the malaria parasite. Here, we present the first successful cloning and expression of DOHH from P. vivax causing tertiary malaria. The nucleic acid sequence of 1041 bp encodes an open reading frame of 346 amino acids. Histidine tagged expression of P. vivax DOHH detected a protein of 39.01 kDa in E. coli. The DOHH protein from P. vivax shares significant amino acid identity to the simian orthologues from P. knowlesi and P. yoelii strain H. In contrast to P. falciparum only four E-Z-type HEAT-like repeats are present in P. vivax DOHH with different homology to phycocyanin lyase subunits from cyanobacteria and in proteins participating in energy metabolism of Archaea and Halobacteria. However, phycocyanin lyase activity is absent in P. vivax DOHH. The dohh gene is present as a single copy gene and transcribed throughout the whole erythrocytic cycle. Specific inhibition of recombinant P. vivax DOHH is possible by complexing the ferrous iron with zileuton, an inhibitor of mammalian 5-lipoxygenase (5-LOX). Ferrous iron in the active site of 5-LOX is coordinated by three conserved histidines and the carboxylate of isoleucine673. Zileuton inhibited the P. vivax DOHH protein with an IC50 of 12,5 nmol determined by a relative quantification by GC/MS. By contrast, the human orthologue is only less affected with an IC50 of 90 nmol suggesting a selective iron-complexing strategy for the parasitic enzyme. OA Förderung 2013
- Published
- 2013
9. Structure of HsdS Subunit from Thermoanaerobacter tengcongensis Sheds Lights on Mechanism of Dynamic Opening and Closing of Type I Methyltransferase
- Author
-
Xiao-Min An, Xiao-Xue Yan, Qun Tang, Pu Gao, and Dong-Cai Liang
- Subjects
Macromolecular Assemblies ,DNA, Bacterial ,Models, Molecular ,Methyltransferase ,Stereochemistry ,Protein Conformation ,Protein subunit ,Biophysics ,lcsh:Medicine ,Thermoanaerobacter ,Biology ,Crystallography, X-Ray ,DNA Restriction-Modification Enzymes ,Biochemistry ,chemistry.chemical_compound ,Protein structure ,Bacterial Proteins ,Transferases ,DNA-binding proteins ,Electrophoretic mobility shift assay ,lcsh:Science ,Protein chemistry ,Multidisciplinary ,Enzyme Classes ,lcsh:R ,Proteins ,DNA ,Genomics ,Methyltransferases ,biology.organism_classification ,Enzyme structure ,Enzymes ,body regions ,Nucleic acids ,Protein Subunits ,chemistry ,Enzyme Structure ,Mutation ,lcsh:Q ,Structural Genomics ,DNA modification ,Research Article ,Protein Binding - Abstract
Type I DNA methyltransferases contain one specificity subunit (HsdS) and two modification subunits (HsdM). The electron microscopy model of M.EcoKI-M2S1 methyltransferase shows a reasonable closed state of this clamp-like enzyme, but the structure of the open state is still unclear. The 1.95 A crystal structure of the specificity subunit from Thermoanaerobacter tengcongensis (TTE-HsdS) shows an unreported open form inter-domain orientation of this subunit. Based on the crystal structure of TTE-HsdS and the closed state model of M.EcoKI-M2S1, we constructed a potential open state model of type I methyltransferase. Mutational studies indicated that two α-helices (aa30-59 and aa466-495) of the TTE-HsdM subunit are important inter-subunit interaction sites in the TTE-M2S1 complex. DNA binding assays also highlighted the importance of the C-terminal region of TTE-HsdM for DNA binding by the TTE-M2S1 complex. On the basis of structural analysis, biochemical experiments and previous studies, we propose a dynamic opening and closing mechanism for type I methyltransferase.
- Published
- 2011
10. The UII/UT System Mediates Upregulation of Proinflammatory Cytokines through p38 MAPK and NF-κB Pathways in LPS-Stimulated Kupffer Cells
- Author
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Chang Gen Ye, Liang Ming Liu, Tong Zhu, Wen Juan Tu, and Dong Yu Liang
- Subjects
Lipopolysaccharides ,Male ,MAPK/ERK pathway ,Kupffer Cells ,MAP Kinase Signaling System ,Urotensins ,p38 mitogen-activated protein kinases ,Blotting, Western ,Interleukin-1beta ,lcsh:Medicine ,Electrophoretic Mobility Shift Assay ,Inflammation ,Biology ,Real-Time Polymerase Chain Reaction ,Receptors, G-Protein-Coupled ,Proinflammatory cytokine ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,medicine ,Animals ,Phosphorylation ,lcsh:Science ,DNA Primers ,Analysis of Variance ,Multidisciplinary ,Reverse Transcriptase Polymerase Chain Reaction ,Tumor Necrosis Factor-alpha ,lcsh:R ,NF-kappa B ,NF-κB ,NFKB1 ,Molecular biology ,Peptide Fragments ,Rats ,chemistry ,Cytokines ,lcsh:Q ,Tumor necrosis factor alpha ,medicine.symptom ,Urotensin-II ,Research Article - Abstract
The urotensin II (UII)/UII receptor (UT) system is closely related to immune inflammation. In acute liver failure (ALF), the UII/UT system can promote the production and release of proinflammatory cytokines, inducing an inflammatory injury response in liver tissue. However, the mechanism by which the hepatic UII/UT system promotes proinflammatory cytokine production and release is not clear. To solve this problem, we used primary Kupffer cells (KCs) as the model system in the current study. The results showed that after lipopolysaccharide (LPS) stimulation, KCs showed significantly increased expression and release of UII/UT and proinflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β). Pretreatment with urantide, which is a UT receptor antagonist, significantly inhibited the LPS-stimulated expression and release of UII/UT, TNF-α, and IL-1β by KCs. In addition, LPS stimulation induced nuclear p38 mitogen-activated protein kinase (MAPK) protein phosphorylation and expression of the nuclear nuclear factor κB (NF-κB) p65 subunit in KCs and enhanced the binding activity of NF-κB to DNA molecules, whereas urantide pretreatment significantly inhibited the LPS-stimulated nuclear expression and activity of these molecules in KCs. Therefore, our conclusion is that the UII/UT system mediates LPS-stimulated production and release of proinflammatory cytokine by KCs, and this mediating effect at least partially relies on the inflammatory signaling pathway molecules p38 MAPK and NF-κB.
- Published
- 2015
11. Mosquitoes of Western Yunnan Province, China: Seasonal Abundance, Diversity, and Arbovirus Associations
- Author
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Zhang, Hai-Lin, primary, Zhang, Yu-Zhen, additional, Yang, Wei-Hong, additional, Feng, Yun, additional, Nasci, Roger S., additional, Yang, Jie, additional, Liu, Yong-Hua, additional, Dong, Chao-Liang, additional, Li, Shi, additional, Zhang, Bao-Sen, additional, Yin, Zheng-Liu, additional, Wang, Pi-Yu, additional, Fu, Shi-Hong, additional, Li, Ming-Hua, additional, Liu, Fen, additional, Zhang, Juan, additional, Sun, Jie, additional, Li, Can-Wei, additional, Gao, Xiao-Yan, additional, Liu, Hong, additional, Wang, Huan-Yu, additional, Petersen, Lyle R., additional, and Liang, Guo-Dong, additional
- Published
- 2013
- Full Text
- View/download PDF
12. Inhibition of UII/UTR System Relieves Acute Inflammation of Liver through Preventing Activation of NF-κB Pathway in ALF Mice
- Author
-
Yan-yan Wang, Yingying Wang, De-Yong Gao, Liang Zhao, Fang-ping Yu, Dong-yu Liang, Chang-gen Ye, Liang-ming Liu, and Zhi‐wen Yang
- Subjects
Lipopolysaccharides ,Male ,Untranslated region ,Anatomy and Physiology ,Mouse ,Gene Expression ,Galactosamine ,Pharmacology ,Receptors, G-Protein-Coupled ,chemistry.chemical_compound ,Immune Physiology ,Molecular Cell Biology ,Mice, Inbred BALB C ,Multidisciplinary ,Cell Death ,Chemistry ,Liver Diseases ,NF-kappa B ,Animal Models ,Signaling in Selected Disciplines ,Liver ,Cytokines ,Medicine ,Tumor necrosis factor alpha ,Inflammation Mediators ,medicine.symptom ,Research Article ,Signal Transduction ,Science ,Urotensins ,Immunology ,Acute Liver Failure ,Inflammation ,Gastroenterology and Hepatology ,Immunological Signaling ,Proinflammatory cytokine ,Model Organisms ,Downregulation and upregulation ,Genetics ,medicine ,Animals ,Biology ,NF-κB ,Liver Failure, Acute ,NFKB1 ,Molecular biology ,Peptide Fragments ,Immune System ,Urotensin-II - Abstract
Urotensin II (UII) is implicated in immune inflammatory diseases through its specific high-affinity UT receptor (UTR). Enhanced expression of UII/UTR was recently demonstrated in the liver with acute liver failure (ALF). Here, we analysed the relationship between UII/UTR expression and ALF in lipopolysaccharide (LPS)/D-galactosamine (GalN)-challenged mice. Thereafter, we investigated the effects produced by the inhibition of UII/UTR system using urantide, a special antagonist of UTR, and the potential molecular mechanisms involved in ALF. Urantide was administered to mice treated with LPS/GalN. Expression of UII/UTR, releases of proinflammatory cytokines including tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and interferon-γ (IFN-γ), and activation of nuclear factor κB (NF-κB) signaling pathway were assessed in the lethal ALF with or without urantide pretreatment. We found that LPS/GalN-challenged mice showed high mortality and marked hepatic inflammatory infiltration and cell apoptosis as well as a significant increase of UII/UTR expression. Urantide pretreatment protected against the injury in liver following downregulation of UII/UTR expression. A close relationship between the acutely flamed hepatic injury and UII/UTR expression was observed. In addition, urantide prevented the increases of proinflammatory cytokines such as TNF-α, IL-1β and IFN-γ, and activation of NF-κB signaling pathway induced by LPS/GalN in mice. Thus, we conclude that UII/UTR system plays a role in LPS/GalN-induced ALF. Urantide has a protective effect on the acutely inflamed injury of liver in part through preventing releases of proinflammatory cytokines and activation of NF-κB pathway.
- Published
- 2013
13. Deoxyhypusine Hydroxylase from Plasmodium vivax, the Neglected Human Malaria Parasite: Molecular Cloning, Expression and Specific Inhibition by the 5-LOX Inhibitor Zileuton.
- Author
-
Atemnkeng, Veronika Anyigoh, Pink, Mario, Schmitz-Spanke, Simone, Wu, Xian-Jun, Dong, Liang-Liang, Zhao, Kai-Hong, May, Caroline, Laufer, Stefan, Langer, Barbara, and Kaiser, Annette
- Subjects
HYDROXYLASES ,PLASMODIUM vivax ,PLASMODIUM ,MOLECULAR cloning ,GENE expression ,LIPOXYGENASES ,PRIMAQUINE ,TARGETED drug delivery ,BIOTECHNOLOGY ,MICROBIOLOGY - Abstract
Primaquine, an 8-aminoquinoline, is the only drug which cures the dormant hypnozoites of persistent liver stages from P. vivax. Increasing resistance needs the discovery of alternative pathways as drug targets to develop novel drug entities. Deoxyhypusine hydroxylase (DOHH) completes hypusine biosynthesis in eukaryotic initiation factor (eIF-5A) which is the only cellular protein known to contain the unusual amino acid hypusine. Modified EIF-5A is important for proliferation of the malaria parasite. Here, we present the first successful cloning and expression of DOHH from P. vivax causing tertiary malaria. The nucleic acid sequence of 1041 bp encodes an open reading frame of 346 amino acids. Histidine tagged expression of P. vivax DOHH detected a protein of 39.01 kDa in E. coli. The DOHH protein from P. vivax shares significant amino acid identity to the simian orthologues from P. knowlesi and P. yoelii strain H. In contrast to P. falciparum only four E-Z-type HEAT-like repeats are present in P. vivax DOHH with different homology to phycocyanin lyase subunits from cyanobacteria and in proteins participating in energy metabolism of Archaea and Halobacteria. However, phycocyanin lyase activity is absent in P. vivax DOHH. The dohh gene is present as a single copy gene and transcribed throughout the whole erythrocytic cycle. Specific inhibition of recombinant P. vivax DOHH is possible by complexing the ferrous iron with zileuton, an inhibitor of mammalian 5-lipoxygenase (5-LOX). Ferrous iron in the active site of 5-LOX is coordinated by three conserved histidines and the carboxylate of isoleucine
673 . Zileuton inhibited the P. vivax DOHH protein with an IC50 of 12,5 nmol determined by a relative quantification by GC/MS. By contrast, the human orthologue is only less affected with an IC50 of 90 nmol suggesting a selective iron-complexing strategy for the parasitic enzyme. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
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