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Mavhandu LG, Cheng H, Bor YC, Tebit DM, Hammarskjold ML, Rekosh D, Bessong PO. Development of a pseudovirus assay and evaluation to screen natural products for inhibition of HIV-1 subtype C reverse transcriptase. J Ethnopharmacol 2020; 258:112931. [PMID: 32360797 DOI: 10.1016/j.jep.2020.112931] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/20/2020] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Medicinal plants are used in the management of Human Immunodeficiency Virus and Acquired Immunodeficiency Syndrome (HIV/AIDS) in many developing country settings where HIV-1 subtype C drives the epidemic. Efforts to identify plant derived molecules with anti-HIV properties require reproducible assay systems for routine screening of selected plant compounds. Although a number of standardized HIV-1 pseudoviruses have been generated to assess infectivity, replicability or reproducibility, HIV-1 subtype C (HIV-1-C) pseudoviruses have not been comprehensively characterized to identify inhibitory plant substances. AIM OF THE STUDY The current study aimed at developing an HIV-1-C pseudovirus assay, and evaluate plant substances targeting reverse transcriptase (RT) activity. MATERIALS AND METHODS HIV-1 subtype C pseudoviruses containing a luciferase reporter gene were generated by transfection of human 293T cells. HIV-1 subtype B (HIV-1-B) wild type pseudoviruses and mutants resistant to nucleoside and non-nucleoside RT inhibitors were also generated and used as controls. Selected plant substances and the RT inhibitors Zidovudine (AZT) and Nevirapine (NVP), were used to evaluate inhibition. Pseudovirus infectivity was determined by luciferase measurement in CF2/CD4+/CCR5 cells, and cytotoxicity was determined using the MTT assay. AZT and NVP inhibited wild type pseudoviruses in a dose dependent manner, with IC50 values in the nanomolar range. RESULTS Pseudoviruses harbouring RT drug resistance mutations were poorly suppressed by AZT and NVP. Catechin, obtained from Peltophorum africanum inhibited HIV-1-C and HIV-1-B pseudoviruses with selective indices of 6304 μM (IC50: 0.49 μM, CC50: 3089 μM) and 1343 μM (IC50: 2.3 μM, CC50: 3089 μM), respectively; while the methanol root crude extract of Elaeodendron transvaalense gave IC50 values of 11.11 μg/ml and 16.86 μg/ml, respectively. CONCLUSION The developed HIV-1-C pseudovirus assay can be used to screen plant substances for RT inhibition, and may have utility in settings with limited access to high level biosafety facilities.
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Affiliation(s)
- Lufuno Grace Mavhandu
- HIV/AIDS & Global Health Research Programme, University of Venda, PMB X5050, Thohoyandou, 0950, South Africa.
| | - Hua Cheng
- Myles H. Thaler Center for AIDS and Human Retrovirus Research, Department of Microbiology, Immunology and Cancer Biology, University of Virginia, P.O. Box 800734, Charlottesville, VA, 22908, USA; Shanghai Municipal Center for Disease Control and Prevention, Department of HIV, STD and Leprosy, 1380 Zhongshan Road, Shanghai, 200336, China.
| | - Yeou-Cheng Bor
- Myles H. Thaler Center for AIDS and Human Retrovirus Research, Department of Microbiology, Immunology and Cancer Biology, University of Virginia, P.O. Box 800734, Charlottesville, VA, 22908, USA; Ambassadors for Christ, 21 Ambassador Drive, Paradise, PA, 17562, USA.
| | - Denis Manga Tebit
- HIV/AIDS & Global Health Research Programme, University of Venda, PMB X5050, Thohoyandou, 0950, South Africa; Myles H. Thaler Center for AIDS and Human Retrovirus Research, Department of Microbiology, Immunology and Cancer Biology, University of Virginia, P.O. Box 800734, Charlottesville, VA, 22908, USA; Global Biomed Scientific LLC, PO Box 2368, Forest, VA, 24551, USA.
| | - Marie-Louise Hammarskjold
- HIV/AIDS & Global Health Research Programme, University of Venda, PMB X5050, Thohoyandou, 0950, South Africa; Myles H. Thaler Center for AIDS and Human Retrovirus Research, Department of Microbiology, Immunology and Cancer Biology, University of Virginia, P.O. Box 800734, Charlottesville, VA, 22908, USA.
| | - David Rekosh
- HIV/AIDS & Global Health Research Programme, University of Venda, PMB X5050, Thohoyandou, 0950, South Africa; Myles H. Thaler Center for AIDS and Human Retrovirus Research, Department of Microbiology, Immunology and Cancer Biology, University of Virginia, P.O. Box 800734, Charlottesville, VA, 22908, USA.
| | - Pascal Obong Bessong
- HIV/AIDS & Global Health Research Programme, University of Venda, PMB X5050, Thohoyandou, 0950, South Africa.
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Pérez-Ruiz E, Decrop D, Ven K, Tripodi L, Leirs K, Rosseels J, van de Wouwer M, Geukens N, De Vos A, Vanmechelen E, Winderickx J, Lammertyn J, Spasic D. Digital ELISA for the quantification of attomolar concentrations of Alzheimer's disease biomarker protein Tau in biological samples. Anal Chim Acta 2018. [PMID: 29530254 DOI: 10.1016/j.aca.2018.02.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The close correlation between Tau pathology and Alzheimer's disease (AD) progression makes this protein a suitable biomarker for diagnosis and monitoring of the disorder evolution. However, the use of Tau in diagnostics has been hampered, as it currently requires collection of cerebrospinal fluid (CSF), which is an invasive clinical procedure. Although measuring Tau-levels in blood plasma would be favorable, the concentrations are below the detection limit of a conventional ELISA. In this work, we developed a digital ELISA for the quantification of attomolar protein Tau concentrations in both buffer and biological samples. Individual Tau molecules were first captured on the surface of magnetic particles using in-house developed antibodies and subsequently isolated into the femtoliter-sized wells of a 2 × 2 mm2 microwell array. Combination of high-affinity antibodies, optimal assay conditions and a digital quantification approach resulted in a 24 ± 7 aM limit of detection (LOD) in buffer samples. Additionally, a dynamic range of 6 orders of magnitude was achieved by combining the digital readout with an analogue approach, allowing quantification from attomolar to picomolar levels of Tau using the same platform. This proves the compatibility of the presented assay with the wide range of Tau concentrations encountered in different biological samples. Next, the developed digital assay was applied to detect total Tau levels in spiked blood plasma. A similar LOD (55 ± 29 aM) was obtained compared to the buffer samples, which was 5000-fold more sensitive than commercially available ELISAs and even outperformed previously reported digital assays with 10-fold increase in sensitivity. Finally, the performance of the developed digital ELISA was assessed by quantifying protein Tau in three clinical CSF samples. Here, a high correlation (i.e. Pearson coefficient of 0.99) was found between the measured percentage of active particles and the reference protein Tau values. The presented digital ELISA technology has great capacity in unlocking the potential of Tau as biomarker for early AD diagnosis.
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Affiliation(s)
- Elena Pérez-Ruiz
- Department of Biosystems, MeBioS-Biosensors Group, KU Leuven, 3001 Leuven, Belgium
| | - Deborah Decrop
- Department of Biosystems, MeBioS-Biosensors Group, KU Leuven, 3001 Leuven, Belgium
| | - Karen Ven
- Department of Biosystems, MeBioS-Biosensors Group, KU Leuven, 3001 Leuven, Belgium
| | - Lisa Tripodi
- Department of Biosystems, MeBioS-Biosensors Group, KU Leuven, 3001 Leuven, Belgium
| | - Karen Leirs
- Department of Biosystems, MeBioS-Biosensors Group, KU Leuven, 3001 Leuven, Belgium
| | - Joelle Rosseels
- Department of Biology, Laboratory of Functional Biology, KU Leuven, 3001 Leuven, Belgium
| | | | - Nick Geukens
- PharmAbs, The KU Leuven Antibody Center, KU Leuven, Belgium
| | - Ann De Vos
- ADx NeuroSciences, Gent-Zwijnaarde, Belgium
| | | | - Joris Winderickx
- Department of Biology, Laboratory of Functional Biology, KU Leuven, 3001 Leuven, Belgium
| | - Jeroen Lammertyn
- Department of Biosystems, MeBioS-Biosensors Group, KU Leuven, 3001 Leuven, Belgium.
| | - Dragana Spasic
- Department of Biosystems, MeBioS-Biosensors Group, KU Leuven, 3001 Leuven, Belgium
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