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Cook JD, Khondker A, Lee JE. Conformational plasticity of the HIV-1 gp41 immunodominant region is recognized by multiple non-neutralizing antibodies. Commun Biol 2022; 5:291. [PMID: 35361878 PMCID: PMC8971491 DOI: 10.1038/s42003-022-03235-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 03/08/2022] [Indexed: 12/17/2022] Open
Abstract
The early humoral immune response to acute HIV-1 infection is largely non-neutralizing. The principal target of these antibodies is the primary immunodominant region (PID) on the gp41 fusion protein. The PID is a highly conserved 15-residue region displayed on the surface of HIV-1 virions. In this study, we analyzed the humoral determinants of HIV-1 gp41 PID binding using biophysical, structural, and computational methods. In complex with a patient-derived near-germline antibody fragment, the PID motif adopts an elongated random coil, whereas the PID bound to affinity-matured Fab adopts a strand-turn-helix conformation. Molecular dynamics simulations showed that the PID is structurally plastic suggesting that the PID can form an ensemble of structural states recognized by various non-neutralizing antibodies, facilitating HIV-1 immunodominance observed in acute and chronic HIV-1 infections. An improved understanding of how the HIV-1 gp41 PID misdirects the early humoral response should guide the development of an effective HIV-1 vaccine. The 15-amino-acid primary immunodominant (PID) region on HIV-1 gp41 adopts an ensemble of conformational states. This conformational plasticity is suggested to misdirect the early humoral immune response.
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Affiliation(s)
- Jonathan D Cook
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Adree Khondker
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Jeffrey E Lee
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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2
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Chen H, Chen Z, Bai N, Yan R, Xu M, Wu W, Liang W, Li H, Mao Y. Construction of a eukaryotic expression system with stable and secretory expression of mycobacterium tuberculosis 38 kDa protein. World J Microbiol Biotechnol 2021; 37:175. [PMID: 34519879 DOI: 10.1007/s11274-021-03143-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 08/24/2021] [Indexed: 11/26/2022]
Abstract
The 38 kDa protein is a major antigen of mycobacterium tuberculosis and has been widely used in TB serodiagnosis, due to its highly sensitivity and specificity. Here we attempt to establish a production platform of recombinant 38 kDa protein in mammalian cells and to evaluate the potential value of 38 kDa protein in TB serodiagnosis. The 38 kDa gene is synthesized and cloned into a lentiviral expressing vector. Recombinant lentiviral vector LV-CMV-38 kDa-eGFP was packaged, titered, and then transduced into HEK 293 T cells. Recombinant cell lines were selected by limiting dilution. Supernatants were collected and purified by HisTrapTM HP column. Western blot showed a molecular weight of approximate 38 kDa in cell supernatants as expected. ELISA assay confirmed the immunological specificity of the obtained protein in the presence of MTB-infected human serum samples. In all, we have obtained a stable cell line with long-term and robust expression of secretory MTB 38 kDa protein, which may provide a promising candidate antigen for the development of TB serological diagnosis.
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Affiliation(s)
- Huiying Chen
- School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, 510515, China
- Sun Yat-Sen Memorial Hospital, Sun Yat-Sen Univsity, Guangzhou, 510000, China
| | - Zedian Chen
- School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, 510515, China
| | - Na Bai
- Department of Nuclear Medicine, Yuxi People's Hospital of Yunnan Province, Yuxi, 653100, China
| | - Renhe Yan
- Guangzhou Bioneeds Biotechnology CO., LTD, Guangzhou, 510000, China
| | - Mingyu Xu
- School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, 510515, China
| | - Wangsheng Wu
- School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, 510515, China
- Animal Science and Technology College, Jilin Agricultural University, Changchun, 130118, China
| | - Wenhan Liang
- School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, 510515, China
| | - Hongwei Li
- School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, 510515, China.
| | - Yingying Mao
- School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, 510515, China.
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Falkenhagen A, Asad S, Read SE, Joshi S. Lentiviral expression system for the purification of secreted proteins from human cell cultures. BMC Biotechnol 2016; 16:66. [PMID: 27590008 PMCID: PMC5009704 DOI: 10.1186/s12896-016-0288-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 07/29/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Recombinant proteins of therapeutic use are ideally produced in human cells to ensure appropriate co- and post-translational modifications. However, purification of secreted proteins from the culture media is impeded by low expression from transfected cell lines and the presence of serum proteins. Here we describe a simple and cost-effective approach based on lentiviral vector-mediated gene delivery and expression of a secreted His-tagged protein from human embryonic kidney 293 T cells and direct affinity chromatography purification from the cell culture media. RESULTS Using a protein-based HIV entry inhibitor, soluble CD4 (sCD4), we demonstrated that 293 T cells transduced with a lentiviral vector mediated over 10-fold higher secretion of sCD4 in comparison to 293 T cells transfected with the corresponding plasmid. Secretion of sCD4 increased with the dose of the lentiviral vector up to a multiplicity of infection of 50. Exchanging the native signal peptide of sCD4 with the signal peptide of human alpha-1 antitrypsin increased expression by 50 %. There was no difference in expression from a monocistronic or bicistronic lentiviral vector. Reduction of the serum concentration in the culture media had no significant effect on the secretion of sCD4. Small-scale purification from 50 ml of culture media with reduced serum content yielded up to 1 mg of pure sCD4. Purified sCD4 bound to recombinant HIV envelope glycoprotein 120 (Env gp120) and inhibited HIV entry at concentrations comparable to published results. CONCLUSION The procedure outlined in this study can be performed without the need for specialized reagents or equipment and could easily be adapted by any laboratory. Furthermore, the method could be used to produce sCD4 fusion proteins or other His-tagged proteins.
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Affiliation(s)
- Alexander Falkenhagen
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Canada
| | - Sabah Asad
- Department of Pediatrics, The Hospital for Sick Children, Toronto, Canada
| | - Stanley E Read
- Department of Pediatrics, The Hospital for Sick Children, Toronto, Canada
| | - Sadhna Joshi
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Canada. .,Department of Molecular Genetics, University of Toronto, Toronto, Canada.
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Vercellotti GM, Zhang P, Nguyen J, Abdulla F, Chen C, Nguyen P, Nowotny C, Steer CJ, Smith A, Belcher JD. Hepatic Overexpression of Hemopexin Inhibits Inflammation and Vascular Stasis in Murine Models of Sickle Cell Disease. Mol Med 2016; 22:437-451. [PMID: 27451971 DOI: 10.2119/molmed.2016.00063] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 07/11/2016] [Indexed: 02/02/2023] Open
Abstract
Sickle cell disease (SCD) patients have low serum hemopexin (Hpx) levels due to chronic hemolysis. We hypothesize that in SCD mice, hepatic overexpression of hemopexin will scavenge the proximal mediator of vascular activation, heme, and will inhibit inflammation and microvascular stasis. To examine the protective role of Hpx in SCD, we transplanted bone marrow from NY1DD SCD mice into Hpx™/™ or Hpx+/+ C57BL/6 mice. Dorsal skin fold chambers were implanted in week 13 post-transplant and microvascular stasis (% non-flowing venules) evaluated in response to heme infusion. Hpx™/™ sickle mice had significantly greater microvascular stasis in response to heme infusion than Hpx+/+ sickle mice (p<0.05), demonstrating the protective effect of Hpx in SCD. We utilized Sleeping Beauty (SB) transposon-mediated gene transfer to overexpress wild-type rat Hpx (wt-Hpx) in NY1DD and Townes-SS SCD mice. Control SCD mice were treated with lactated Ringer's solution (LRS) or a luciferase (Luc) plasmid. Plasma and hepatic Hpx were significantly increased compared to LRS and Luc controls. Microvascular stasis in response to heme infusion in NY1DD and Townes-SS mice overexpressing wt-Hpx had significantly less stasis than controls (p<0.05). Wt-Hpx overexpression markedly increased hepatic nuclear Nrf2 expression, HO-1 activity and protein, the heme-Hpx binding protein and scavenger receptor, CD91/LRP1 and decreased NF-κB activation. Two missense (ms)-Hpx SB-constructs that bound neither heme nor the Hpx receptor, CD91/LRP1, did not prevent heme-induced stasis. In conclusion, increasing Hpx levels in transgenic sickle mice via gene transfer activates the Nrf2/HO-1 anti-oxidant axis and ameliorates inflammation and vaso-occlusion.
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Affiliation(s)
- Gregory M Vercellotti
- Division of Hematology, Oncology and Transplantation, Department of Medicine, 420 Delaware St SE, MMC 480, University of Minnesota, Minneapolis, Minnesota, USA.,Vascular Biology Center, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ping Zhang
- Division of Hematology, Oncology and Transplantation, Department of Medicine, 420 Delaware St SE, MMC 480, University of Minnesota, Minneapolis, Minnesota, USA.,Vascular Biology Center, University of Minnesota, Minneapolis, Minnesota, USA
| | - Julia Nguyen
- Division of Hematology, Oncology and Transplantation, Department of Medicine, 420 Delaware St SE, MMC 480, University of Minnesota, Minneapolis, Minnesota, USA.,Vascular Biology Center, University of Minnesota, Minneapolis, Minnesota, USA
| | - Fuad Abdulla
- Division of Hematology, Oncology and Transplantation, Department of Medicine, 420 Delaware St SE, MMC 480, University of Minnesota, Minneapolis, Minnesota, USA.,Vascular Biology Center, University of Minnesota, Minneapolis, Minnesota, USA
| | - Chunsheng Chen
- Division of Hematology, Oncology and Transplantation, Department of Medicine, 420 Delaware St SE, MMC 480, University of Minnesota, Minneapolis, Minnesota, USA.,Vascular Biology Center, University of Minnesota, Minneapolis, Minnesota, USA
| | - Phong Nguyen
- Division of Hematology, Oncology and Transplantation, Department of Medicine, 420 Delaware St SE, MMC 480, University of Minnesota, Minneapolis, Minnesota, USA.,Vascular Biology Center, University of Minnesota, Minneapolis, Minnesota, USA
| | - Carlos Nowotny
- Division of Hematology, Oncology and Transplantation, Department of Medicine, 420 Delaware St SE, MMC 480, University of Minnesota, Minneapolis, Minnesota, USA.,Vascular Biology Center, University of Minnesota, Minneapolis, Minnesota, USA
| | - Clifford J Steer
- Division of Gastroenterology, Department of Medicine, and Department of Genetics, Cell Biology and Development, 420 Delaware St SE, MMC 36, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ann Smith
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - John D Belcher
- Division of Hematology, Oncology and Transplantation, Department of Medicine, 420 Delaware St SE, MMC 480, University of Minnesota, Minneapolis, Minnesota, USA.,Vascular Biology Center, University of Minnesota, Minneapolis, Minnesota, USA
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5
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Olde Loohuis NFM, Kole K, Glennon JC, Karel P, Van der Borg G, Van Gemert Y, Van den Bosch D, Meinhardt J, Kos A, Shahabipour F, Tiesinga P, van Bokhoven H, Martens GJM, Kaplan BB, Homberg JR, Aschrafi A. Elevated microRNA-181c and microRNA-30d levels in the enlarged amygdala of the valproic acid rat model of autism. Neurobiol Dis 2015; 80:42-53. [PMID: 25986729 DOI: 10.1016/j.nbd.2015.05.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 04/14/2015] [Accepted: 05/10/2015] [Indexed: 11/17/2022] Open
Abstract
Autism spectrum disorders are severe neurodevelopmental disorders, marked by impairments in reciprocal social interaction, delays in early language and communication, and the presence of restrictive, repetitive and stereotyped behaviors. Accumulating evidence suggests that dysfunction of the amygdala may be partially responsible for the impairment of social behavior that is a hallmark feature of ASD. Our studies suggest that a valproic acid (VPA) rat model of ASD exhibits an enlargement of the amygdala as compared to controls rats, similar to that observed in adolescent ASD individuals. Since recent research suggests that altered neuronal development and morphology, as seen in ASD, may result from a common post-transcriptional process that is under tight regulation by microRNAs (miRs), we examined genome-wide transcriptomics expression in the amygdala of rats prenatally exposed to VPA, and detected elevated miR-181c and miR-30d expression levels as well as dysregulated expression of their cognate mRNA targets encoding proteins involved in neuronal system development. Furthermore, selective suppression of miR-181c function attenuates neurite outgrowth and branching, and results in reduced synaptic density in primary amygdalar neurons in vitro. Collectively, these results implicate the small non-coding miR-181c in neuronal morphology, and provide a framework of understanding how dysregulation of a neurodevelopmentally relevant miR in the amygdala may contribute to the pathophysiology of ASD.
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Affiliation(s)
- N F M Olde Loohuis
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - K Kole
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - J C Glennon
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - P Karel
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - G Van der Borg
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Y Van Gemert
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - D Van den Bosch
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - J Meinhardt
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - A Kos
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - F Shahabipour
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - P Tiesinga
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - H van Bokhoven
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands; Department of Human Genetics, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - G J M Martens
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behavior, Nijmegen Centre for Molecular Life Sciences (NCMLS), Radboud University Nijmegen, Nijmegen, The Netherlands
| | - B B Kaplan
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - J R Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - A Aschrafi
- Department of Neuroinformatics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands.
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Efficient production and purification of recombinant human interleukin-12 (IL-12) overexpressed in mammalian cells without affinity tag. Protein Expr Purif 2014; 102:76-84. [PMID: 25123642 DOI: 10.1016/j.pep.2014.07.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 07/04/2014] [Accepted: 07/08/2014] [Indexed: 11/20/2022]
Abstract
Interleukin-12 is a heterodimeric, pro-inflammatory cytokine that is a key driver of cell-mediated immunity. Clinical interest in IL-12 is significant due to its potent anti-tumor activity and efficacy in controlling certain infectious diseases such as Leishmaniasis and Listeria infection. For clinical applications, the ease of production and purification of IL-12 and the associated cost continues to be a consideration. In this context, we report a simple and effective heparin-affinity based purification of recombinant human IL-12 (hIL-12) from the serum-free supernatants of stable IL-12-transduced HEK293 cells. Fractionation of culture supernatants on heparin Sepharose columns revealed that hIL-12 elutes as a single peak in 500 mM NaCl. Coomassie staining and Western blot analysis showed that hIL-12 eluted in 500 mM NaCl is homogeneous. Purity of hIL-12 was ascertained by RP-HPLC and ESI-MS analysis, and found to be ∼98%. Western blot analysis, using monoclonal antibodies, demonstrated that the crucial inter-subunit disulfide bond linking the p35 and p40 subunits is intact in the purified hIL-12. Results of far UV circular dichroism, steady-state tryptophan fluorescence, and differential scanning calorimetry experiments suggest that purified hIL-12 is in its stable native conformation. Enzyme linked immunosorbent assays (ELISAs) and bioactivity studies demonstrate that hIL-12 is obtained in high yields (0.31±0.05 mg/mL of the culture medium) and is also fully bioactive. Isothermal titration calorimetry data show that IL-12 exhibits a moderate binding affinity (Kd(app)=69±1 μM) to heparin. The purification method described in this study is expected to provide greater impetus for research on the role of heparin in the regulation of the function of IL-12. In addition, the results of this study provide an avenue to obtain high amounts of IL-12 required for structural studies which are aimed at the development of novel IL-12-based therapeutics.
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