1
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Promsote W, Xu L, Hataye J, Fabozzi G, March K, Almasri CG, DeMouth ME, Lovelace SE, Talana CA, Doria-Rose NA, McKee K, Hait SH, Casazza JP, Ambrozak D, Beninga J, Rao E, Furtmann N, Birkenfeld J, McCarthy E, Todd JP, Petrovas C, Connors M, Hebert AT, Beck J, Shen J, Zhang B, Levit M, Wei RR, Yang ZY, Pegu A, Mascola JR, Nabel GJ, Koup RA. Trispecific antibody targeting HIV-1 and T cells activates and eliminates latently-infected cells in HIV/SHIV infections. Nat Commun 2023; 14:3719. [PMID: 37349337 PMCID: PMC10287722 DOI: 10.1038/s41467-023-39265-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 05/30/2023] [Indexed: 06/24/2023] Open
Abstract
Agents that can simultaneously activate latent HIV, increase immune activation and enhance the killing of latently-infected cells represent promising approaches for HIV cure. Here, we develop and evaluate a trispecific antibody (Ab), N6/αCD3-αCD28, that targets three independent proteins: (1) the HIV envelope via the broadly reactive CD4-binding site Ab, N6; (2) the T cell antigen CD3; and (3) the co-stimulatory molecule CD28. We find that the trispecific significantly increases antigen-specific T-cell activation and cytokine release in both CD4+ and CD8+ T cells. Co-culturing CD4+ with autologous CD8+ T cells from ART-suppressed HIV+ donors with N6/αCD3-αCD28, results in activation of latently-infected cells and their elimination by activated CD8+ T cells. This trispecific antibody mediates CD4+ and CD8+ T-cell activation in non-human primates and is well tolerated in vivo. This HIV-directed antibody therefore merits further development as a potential intervention for the eradication of latent HIV infection.
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Affiliation(s)
- Wanwisa Promsote
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ling Xu
- Sanofi, 640 Memorial Dr., Cambridge, MA, 02139, USA
- ModeX Therapeutics Inc., 22 Strathmore Road, Natick, MA, 01760, USA
| | - Jason Hataye
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Giulia Fabozzi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kylie March
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Cassandra G Almasri
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Megan E DeMouth
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sarah E Lovelace
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Chloe Adrienna Talana
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Nicole A Doria-Rose
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Krisha McKee
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sabrina Helmold Hait
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Joseph P Casazza
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - David Ambrozak
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | | | - Ercole Rao
- Sanofi, 640 Memorial Dr., Cambridge, MA, 02139, USA
| | | | - Joerg Birkenfeld
- Sanofi, 640 Memorial Dr., Cambridge, MA, 02139, USA
- Perspix Biotech GmbH, FiZ Frankfurt Innovation Center Biotechnology, Altenhoeferallee 3, 60438, Frankfurt, Germany
| | - Elizabeth McCarthy
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - John-Paul Todd
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Constantinos Petrovas
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- Department of Laboratory Medicine and Pathology, Institute of Pathology, Lausanne University Hospital (chuv) and University of Lausanne, Lausanne, Switzerland
| | | | | | - Jeremy Beck
- Sanofi, 640 Memorial Dr., Cambridge, MA, 02139, USA
| | - Junqing Shen
- Sanofi, 640 Memorial Dr., Cambridge, MA, 02139, USA
| | - Bailin Zhang
- Sanofi, 640 Memorial Dr., Cambridge, MA, 02139, USA
| | | | - Ronnie R Wei
- Sanofi, 640 Memorial Dr., Cambridge, MA, 02139, USA
- ModeX Therapeutics Inc., 22 Strathmore Road, Natick, MA, 01760, USA
| | - Zhi-Yong Yang
- Sanofi, 640 Memorial Dr., Cambridge, MA, 02139, USA
- ModeX Therapeutics Inc., 22 Strathmore Road, Natick, MA, 01760, USA
| | - Amarendra Pegu
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - John R Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
- ModeX Therapeutics Inc., 22 Strathmore Road, Natick, MA, 01760, USA
| | - Gary J Nabel
- Sanofi, 640 Memorial Dr., Cambridge, MA, 02139, USA.
- ModeX Therapeutics Inc., 22 Strathmore Road, Natick, MA, 01760, USA.
| | - Richard A Koup
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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2
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Misasi J, Wei RR, Wang L, Pegu A, Wei CJ, Oloniniyi OK, Zhou T, Moliva JI, Zhao B, Choe M, Yang ES, Zhang Y, Boruszczak M, Chen M, Leung K, Li J, Yang ZY, Andersen H, Carlton K, Godbole S, Harris DR, Henry AR, Ivleva VB, Lei P, Liu C, Longobardi L, Merriam JS, Nase D, Olia AS, Pessaint L, Porto M, Shi W, Wolff JJ, Douek DC, Suthar MS, Gall J, Koup RA, Kwong PD, Mascola JR, Nabel GJ, Sullivan NJ. A multispecific antibody prevents immune escape and confers pan-SARS-CoV-2 neutralization. bioRxiv 2022:2022.07.29.502029. [PMID: 35982683 PMCID: PMC9387125 DOI: 10.1101/2022.07.29.502029] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Despite effective countermeasures, SARS-CoV-2 persists worldwide due to its ability to diversify and evade human immunity1. This evasion stems from amino-acid substitutions, particularly in the receptor-binding domain of the spike, that confer resistance to vaccines and antibodies 2-16. To constrain viral escape through resistance mutations, we combined antibody variable regions that recognize different receptor binding domain (RBD) sites17,18 into multispecific antibodies. Here, we describe multispecific antibodies, including a trispecific that prevented virus escape >3000-fold more potently than the most effective clinical antibody or mixtures of the parental antibodies. Despite being generated before the evolution of Omicron, this trispecific antibody potently neutralized all previous variants of concern and major Omicron variants, including the most recent BA.4/BA.5 strains at nanomolar concentrations. Negative stain electron microscopy revealed that synergistic neutralization was achieved by engaging different epitopes in specific orientations that facilitated inter-spike binding. An optimized trispecific antibody also protected Syrian hamsters against Omicron variants BA.1, BA.2 and BA.5, each of which uses different amino acid substitutions to mediate escape from therapeutic antibodies. Such multispecific antibodies decrease the likelihood of SARS-CoV-2 escape, simplify treatment, and maximize coverage, providing a strategy for universal antibody therapies that could help eliminate pandemic spread for this and other pathogens.
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Affiliation(s)
- John Misasi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ronnie R. Wei
- Modex Therapeutics Inc., an OPKO Health Company, Natick, MA 01760, USA
| | - Lingshu Wang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Chih-Jen Wei
- Modex Therapeutics Inc., an OPKO Health Company, Natick, MA 01760, USA
| | - Olamide K. Oloniniyi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tongqing Zhou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Juan I. Moliva
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bingchun Zhao
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Misook Choe
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Eun Sung Yang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yi Zhang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Marika Boruszczak
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Man Chen
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kwan Leung
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Juan Li
- Modex Therapeutics Inc., an OPKO Health Company, Natick, MA 01760, USA
| | - Zhi-Yong Yang
- Modex Therapeutics Inc., an OPKO Health Company, Natick, MA 01760, USA
| | | | - Kevin Carlton
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sucheta Godbole
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Darcy R. Harris
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Amy R. Henry
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Vera B. Ivleva
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Paula Lei
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Cuiping Liu
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lindsay Longobardi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jonah S. Merriam
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Adam S. Olia
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | | - Wei Shi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jeremy J. Wolff
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Daniel C. Douek
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mehul S. Suthar
- Department of Pediatrics, Emory Vaccine Center, Emory National Primate Research Center, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jason Gall
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Richard A. Koup
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Peter D. Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - John R. Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gary J. Nabel
- Modex Therapeutics Inc., an OPKO Health Company, Natick, MA 01760, USA
| | - Nancy J. Sullivan
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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3
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Pegu A, Xu L, DeMouth ME, Fabozzi G, March K, Almasri CG, Cully MD, Wang K, Yang ES, Dias J, Fennessey CM, Hataye J, Wei RR, Rao E, Casazza JP, Promsote W, Asokan M, McKee K, Schmidt SD, Chen X, Liu C, Shi W, Geng H, Foulds KE, Kao SF, Noe A, Li H, Shaw GM, Zhou T, Petrovas C, Todd JP, Keele BF, Lifson JD, Doria-Rose N, Koup RA, Yang ZY, Nabel GJ, Mascola JR. Potent anti-viral activity of a trispecific HIV neutralizing antibody in SHIV-infected monkeys. Cell Rep 2022; 38:110199. [PMID: 34986348 PMCID: PMC8767641 DOI: 10.1016/j.celrep.2021.110199] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/20/2021] [Accepted: 12/10/2021] [Indexed: 01/07/2023] Open
Abstract
Broadly neutralizing antibodies (bNAbs) represent an alternative to drug therapy for the treatment of HIV-1 infection. Immunotherapy with single bNAbs often leads to emergence of escape variants, suggesting a potential benefit of combination bNAb therapy. Here, a trispecific bNAb reduces viremia 100- to 1000-fold in viremic SHIV-infected macaques. After treatment discontinuation, viremia rebounds transiently and returns to low levels, through CD8-mediated immune control. These viruses remain sensitive to the trispecific antibody, despite loss of sensitivity to one of the parental bNAbs. Similarly, the trispecific bNAb suppresses the emergence of resistance in viruses derived from HIV-1-infected subjects, in contrast to parental bNAbs. Trispecific HIV-1 neutralizing antibodies, therefore, mediate potent antiviral activity in vivo and may minimize the potential for immune escape.
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Affiliation(s)
- Amarendra Pegu
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Ling Xu
- Sanofi, 640 Memorial Dr., Cambridge MA, USA
| | - Megan E. DeMouth
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Giulia Fabozzi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Kylie March
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Cassandra G. Almasri
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Michelle D. Cully
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Keyun Wang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Eun Sung Yang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Joana Dias
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Christine M. Fennessey
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Jason Hataye
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | | | - Ercole Rao
- Sanofi, 640 Memorial Dr., Cambridge MA, USA
| | - Joseph P. Casazza
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Wanwisa Promsote
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Mangaiarkarasi Asokan
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Krisha McKee
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Stephen D. Schmidt
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Xuejun Chen
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Cuiping Liu
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Wei Shi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Hui Geng
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Kathryn E. Foulds
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Shing-Fen Kao
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Amy Noe
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Hui Li
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - George M. Shaw
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Tongqing Zhou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Constantinos Petrovas
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - John-Paul Todd
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Brandon F. Keele
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Jeffrey D. Lifson
- AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Nicole Doria-Rose
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Richard A. Koup
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | | | - Gary J. Nabel
- Sanofi, 640 Memorial Dr., Cambridge MA, USA,To whom correspondence should be addressed: G.J.N: , phone: 857-233-9936; J.R.M. ; 301-496-1852
| | - John R. Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA,Lead contact,To whom correspondence should be addressed: G.J.N: , phone: 857-233-9936; J.R.M. ; 301-496-1852
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4
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Pan LP, Gao MQ, Jia HY, Huang ML, Wei RR, Sun Q, Xing AY, Du BP, Zhang ZD. [Diagnostic performance of a novel Mycobacterium Tuberculosis specific T-Cell based assay for tuberculosis]. Zhonghua Jie He He Hu Xi Za Zhi 2021; 44:443-449. [PMID: 34865364 DOI: 10.3760/cma.j.cn112147-20200821-00916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Objective: To evaluate the diagnosic performance of a novel Mycobacterium tuberculosis (MTB) specific T-cell based assay for tuberculosis, which targets the mRNA detection of interferon gamma-induced protein 10 (IP-10). Methods: Suspected tuberculosis patients were prospectively and consecutively recruited in Beijing Chest Hospital between March 2018 and November 2019, and individuals with lower risk of MTB infection were also recruited. IP-10.TB and T-SPOT.TB assays were simulataneously performed on peripheral blood samples. The diagnostic performance of IP-10.TB and T-SPOT.TB were analyzed using the receiver operating characteristic curve. Accordance of IP-10.TB and T-SPOT.TB was analyzed by Cohen's kappa test, while the correlation between the expression level of IP-10 mRNA in IP-10.TB test and the number of SFCs in T-SPOT.TB test were analyzed by Pearson correlation test. Results: A total of 235 patients with tuberculosis, 110 patients with other diseases and 153 individuals with lower risk of MTB infection were included in the final analysis. No significant difference was detected in the rate of indeterminate results between IP-10.TB assay (3/498, 0.60%) and T-SPOT.TB assay (6/498, 1.21%). The total sensitivity and specificity of IP-10.TB assay were 91.3% (95%CI 86.8%-94.6%) and 81.1% (95%CI 75.8%-85.7%). The specificity of IP-10.TB in individuals with lower risk of MTB infection was 98.0% (95%CI 94.4%-99.6%). The total sensitivity and specificity of T-SPOT.TB assay were 93.0% (95%CI 88.9%-96.0%) and 83.8% (95%CI 78.7%-88.1%). The specificity of T-SPOT.TB in individuals with lower risk of MTB infection was 100% (95%CI 97.6%-100.0%). No significant differences were detected in sensitivity and specificity between IP-10.TB and T-SPOT.TB assays (P>0.05). The positive coincidence rate of these 2 methods was 91.0% (95%CI 87.5%-94.5%), and the negative coincidence rate was 88.9% (95%CI 84.9%-92.9%) and the total coincidence rate was 90.0% (95%CI 87.3%-92.6%). The Cohen's kappa value was 0.80 (95%CI 0.75-0.85, P<0.001) between IP-10.TB and T-SPOT.TB assays. Conclusion: These results showed that the diagnostic performance of IP-10.TB was consistent with that in T-SPOT.TB, and this test could be a novel adjunctive tool for the diagnosis of tuberculosis.
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Affiliation(s)
- L P Pan
- Department of Tuberculosis, Beijing Chest Hospital Affiliated to Capital Medical University, Beijing 110149, China
| | - M Q Gao
- Department of Tuberculosis, Beijing Chest Hospital Affiliated to Capital Medical University, Beijing 110149, China
| | - H Y Jia
- Department of Tuberculosis, Beijing Chest Hospital Affiliated to Capital Medical University, Beijing 110149, China
| | - M L Huang
- Department of Tuberculosis, Beijing Chest Hospital Affiliated to Capital Medical University, Beijing 110149, China
| | - R R Wei
- Department of Tuberculosis, Beijing Chest Hospital Affiliated to Capital Medical University, Beijing 110149, China
| | - Q Sun
- Department of Tuberculosis, Beijing Chest Hospital Affiliated to Capital Medical University, Beijing 110149, China
| | - A Y Xing
- Department of Tuberculosis, Beijing Chest Hospital Affiliated to Capital Medical University, Beijing 110149, China
| | - B P Du
- Department of Tuberculosis, Beijing Chest Hospital Affiliated to Capital Medical University, Beijing 110149, China
| | - Z D Zhang
- Department of Tuberculosis, Beijing Chest Hospital Affiliated to Capital Medical University, Beijing 110149, China
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5
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Kamp HD, Swanson KA, Wei RR, Dhal PK, Dharanipragada R, Kern A, Sharma B, Sima R, Hajdusek O, Hu LT, Wei CJ, Nabel GJ. Design of a broadly reactive Lyme disease vaccine. NPJ Vaccines 2020; 5:33. [PMID: 32377398 PMCID: PMC7195412 DOI: 10.1038/s41541-020-0183-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 03/31/2020] [Indexed: 02/02/2023] Open
Abstract
A growing global health concern, Lyme disease has become the most common tick-borne disease in the United States and Europe. Caused by the bacterial spirochete Borrelia burgdorferi sensu lato (sl), this disease can be debilitating if not treated promptly. Because diagnosis is challenging, prevention remains a priority; however, a previously licensed vaccine is no longer available to the public. Here, we designed a six component vaccine that elicits antibody (Ab) responses against all Borrelia strains that commonly cause Lyme disease in humans. The outer surface protein A (OspA) of Borrelia was fused to a bacterial ferritin to generate self-assembling nanoparticles. OspA-ferritin nanoparticles elicited durable high titer Ab responses to the seven major serotypes in mice and non-human primates at titers higher than a previously licensed vaccine. This response was durable in rhesus macaques for more than 6 months. Vaccination with adjuvanted OspA-ferritin nanoparticles stimulated protective immunity from both B. burgdorferi and B. afzelii infection in a tick-fed murine challenge model. This multivalent Lyme vaccine offers the potential to limit the spread of Lyme disease.
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Affiliation(s)
| | | | | | | | | | - Aurelie Kern
- Department of Molecular Biology and Microbiology, Tufts University, 136 Harrison Ave, Boston, MA 02111 USA
| | - Bijaya Sharma
- Department of Molecular Biology and Microbiology, Tufts University, 136 Harrison Ave, Boston, MA 02111 USA
| | - Radek Sima
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Ondrej Hajdusek
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Linden T. Hu
- Department of Molecular Biology and Microbiology, Tufts University, 136 Harrison Ave, Boston, MA 02111 USA
| | - Chih-Jen Wei
- Sanofi, 640 Memorial Dr, Cambridge, MA 01239 USA
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6
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Wu L, Seung E, Xu L, Rao E, Lord DM, Wei RR, Cortez-Retamozo V, Ospina B, Posternak V, Ulinski G, Piepenhagen P, Francesconi E, El-Murr N, Beil C, Kirby P, Li A, Fretland J, Vicente R, Deng G, Dabdoubi T, Cameron B, Bertrand T, Ferrari P, Pouzieux S, Lemoine C, Prades C, Park A, Qiu H, Song Z, Zhang B, Sun F, Chiron M, Rao S, Radošević K, Yang ZY, Nabel GJ. Trispecific antibodies enhance the therapeutic efficacy of tumor-directed T cells through T cell receptor co-stimulation. ACTA ACUST UNITED AC 2019; 1:86-98. [DOI: 10.1038/s43018-019-0004-z] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 10/23/2019] [Indexed: 12/26/2022]
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7
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Abstract
Metelimumab (CAT192) is a human IgG4 monoclonal antibody developed as a TGFβ1-specific antagonist. It was tested in clinical trials for the treatment of scleroderma but later terminated due to lack of efficacy. Subsequent characterization of CAT192 indicated that its TGFβ1 binding affinity was reduced by ∼50-fold upon conversion from the parental single-chain variable fragment (scFv) to IgG4. We hypothesized this result was due to decreased conformational flexibility of the IgG that could be altered via engineering. Therefore, we designed insertion mutants in the elbow region and screened for binding and potency. Our results indicated that increasing the elbow region linker length in each chain successfully restored the isoform-specific and high affinity binding of CAT192 to TGFβ1. The crystal structure of the high binding affinity mutant displays large conformational rearrangements of the variable domains compared to the wild-type antigen-binding fragment (Fab) and the low binding affinity mutants. Insertion of two glycines in both the heavy and light chain elbow regions provided sufficient flexibility for the variable domains to extend further apart than the wild-type Fab, and allow the CDR3s to make additional interactions not seen in the wild-type Fab structure. These interactions coupled with the dramatic conformational changes provide a possible explanation of how the scFv and elbow-engineered Fabs bind TGFβ1 with high affinity. This study demonstrates the benefits of re-examining both structure and function when converting scFv to IgG molecules, and highlights the potential of structure-based engineering to produce fully functional antibodies.
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Affiliation(s)
- Dana M Lord
- a Biologics Research, Sanofi , Framingham , MA , USA
| | - Julie J Bird
- a Biologics Research, Sanofi , Framingham , MA , USA
| | | | - Annie Best
- b Biopharmaceutics Development, Sanofi , Framingham , MA , USA
| | - Anna Park
- a Biologics Research, Sanofi , Framingham , MA , USA
| | - Ronnie R Wei
- a Biologics Research, Sanofi , Framingham , MA , USA
| | - Huawei Qiu
- a Biologics Research, Sanofi , Framingham , MA , USA
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8
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Xu L, Pegu A, Rao E, Doria-Rose N, Beninga J, McKee K, Lord DM, Wei RR, Deng G, Louder M, Schmidt SD, Mankoff Z, Wu L, Asokan M, Beil C, Lange C, Leuschner WD, Kruip J, Sendak R, Kwon YD, Zhou T, Chen X, Bailer RT, Wang K, Choe M, Tartaglia LJ, Barouch DH, O'Dell S, Todd JP, Burton DR, Roederer M, Connors M, Koup RA, Kwong PD, Yang ZY, Mascola JR, Nabel GJ. Trispecific broadly neutralizing HIV antibodies mediate potent SHIV protection in macaques. Science 2017; 358:85-90. [PMID: 28931639 DOI: 10.1126/science.aan8630] [Citation(s) in RCA: 210] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 08/28/2017] [Indexed: 12/25/2022]
Abstract
The development of an effective AIDS vaccine has been challenging because of viral genetic diversity and the difficulty of generating broadly neutralizing antibodies (bnAbs). We engineered trispecific antibodies (Abs) that allow a single molecule to interact with three independent HIV-1 envelope determinants: the CD4 binding site, the membrane-proximal external region (MPER), and the V1V2 glycan site. Trispecific Abs exhibited higher potency and breadth than any previously described single bnAb, showed pharmacokinetics similar to those of human bnAbs, and conferred complete immunity against a mixture of simian-human immunodeficiency viruses (SHIVs) in nonhuman primates, in contrast to single bnAbs. Trispecific Abs thus constitute a platform to engage multiple therapeutic targets through a single protein, and they may be applicable for treatment of diverse diseases, including infections, cancer, and autoimmunity.
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Affiliation(s)
- Ling Xu
- Sanofi, 640 Memorial Drive, Cambridge, MA 02139, USA
| | - Amarendra Pegu
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Ercole Rao
- Sanofi, 640 Memorial Drive, Cambridge, MA 02139, USA
| | - Nicole Doria-Rose
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | | | - Krisha McKee
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Dana M Lord
- Sanofi, 640 Memorial Drive, Cambridge, MA 02139, USA
| | - Ronnie R Wei
- Sanofi, 640 Memorial Drive, Cambridge, MA 02139, USA
| | - Gejing Deng
- Sanofi, 640 Memorial Drive, Cambridge, MA 02139, USA
| | - Mark Louder
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Stephen D Schmidt
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Zachary Mankoff
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Lan Wu
- Sanofi, 640 Memorial Drive, Cambridge, MA 02139, USA
| | - Mangaiarkarasi Asokan
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | | | | | | | - Jochen Kruip
- Sanofi, 640 Memorial Drive, Cambridge, MA 02139, USA
| | | | - Young Do Kwon
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Tongqing Zhou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Xuejun Chen
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Robert T Bailer
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Keyun Wang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Misook Choe
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Lawrence J Tartaglia
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.,Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA
| | - Dan H Barouch
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.,Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA
| | - Sijy O'Dell
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - John-Paul Todd
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Dennis R Burton
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA.,Department of Immunology and Microbiology, International AIDS Vaccine Initiative (IAVI) Neutralizing Antibody Center, Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Mario Roederer
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Mark Connors
- National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Richard A Koup
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Zhi-Yong Yang
- Sanofi, 640 Memorial Drive, Cambridge, MA 02139, USA
| | - John R Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA.
| | - Gary J Nabel
- Sanofi, 640 Memorial Drive, Cambridge, MA 02139, USA.
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9
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Qiu H, Honey DM, Kingsbury JS, Park A, Boudanova E, Wei RR, Pan CQ, Edmunds T. Impact of cysteine variants on the structure, activity, and stability of recombinant human α-galactosidase A. Protein Sci 2015; 24:1401-11. [PMID: 26044846 DOI: 10.1002/pro.2719] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 05/26/2015] [Accepted: 05/28/2015] [Indexed: 11/07/2022]
Abstract
Recombinant human α-galactosidase A (rhαGal) is a homodimeric glycoprotein deficient in Fabry disease, a lysosomal storage disorder. In this study, each cysteine residue in rhαGal was replaced with serine to understand the role each cysteine plays in the enzyme structure, function, and stability. Conditioned media from transfected HEK293 cells were assayed for rhαGal expression and enzymatic activity. Activity was only detected in the wild type control and in mutants substituting the free cysteine residues (C90S, C174S, and the C90S/C174S). Cysteine-to-serine substitutions at the other sites lead to the loss of expression and/or activity, consistent with their involvement in the disulfide bonds found in the crystal structure. Purification and further characterization confirmed that the C90S, C174S, and the C90S/C174S mutants are enzymatically active, structurally intact and thermodynamically stable as measured by circular dichroism and thermal denaturation. The purified inactive C142S mutant appeared to have lost part of its alpha-helix secondary structure and had a lower apparent melting temperature. Saturation mutagenesis study on Cys90 and Cys174 resulted in partial loss of activity for Cys174 mutants but multiple mutants at Cys90 with up to 87% higher enzymatic activity (C90T) compared to wild type, suggesting that the two free cysteines play differential roles and that the activity of the enzyme can be modulated by side chain interactions of the free Cys residues. These results enhanced our understanding of rhαGal structure and function, particularly the critical roles that cysteines play in structure, stability, and enzymatic activity.
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Affiliation(s)
- Huawei Qiu
- Sanofi Biotherapeutics, Framingham, Massachusetts, 01701
| | - Denise M Honey
- Sanofi Biotherapeutics, Framingham, Massachusetts, 01701
| | | | - Anna Park
- Sanofi Biotherapeutics, Framingham, Massachusetts, 01701
| | | | - Ronnie R Wei
- Sanofi Biotherapeutics, Framingham, Massachusetts, 01701
| | - Clark Q Pan
- Sanofi Biotherapeutics, Framingham, Massachusetts, 01701
| | - Tim Edmunds
- Sanofi Biotherapeutics, Framingham, Massachusetts, 01701
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10
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Moulin A, Mathieu M, Lawrence C, Bigelow R, Levine M, Hamel C, Marquette JP, Le Parc J, Loux C, Ferrari P, Capdevila C, Dumas J, Dumas B, Rak A, Bird J, Qiu H, Pan CQ, Edmunds T, Wei RR. Structures of a pan-specific antagonist antibody complexed to different isoforms of TGFβ reveal structural plasticity of antibody-antigen interactions. Protein Sci 2014; 23:1698-707. [PMID: 25209176 DOI: 10.1002/pro.2548] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 09/04/2014] [Indexed: 11/08/2022]
Abstract
Various important biological pathways are modulated by TGFβ isoforms; as such they are potential targets for therapeutic intervention. Fresolimumab, also known as GC1008, is a pan-TGFβ neutralizing antibody that has been tested clinically for several indications including an ongoing trial for focal segmental glomerulosclerosis. The structure of the antigen-binding fragment of fresolimumab (GC1008 Fab) in complex with TGFβ3 has been reported previously, but the structural capacity of fresolimumab to accommodate tight interactions with TGFβ1 and TGFβ2 was insufficiently understood. We report the crystal structure of the single-chain variable fragment of fresolimumab (GC1008 scFv) in complex with target TGFβ1 to a resolution of 3.00 Å and the crystal structure of GC1008 Fab in complex with TGFβ2 to 2.83 Å. The structures provide further insight into the details of TGFβ recognition by fresolimumab, give a clear indication of the determinants of fresolimumab pan-specificity and provide potential starting points for the development of isoform-specific antibodies using a fresolimumab scaffold.
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Affiliation(s)
- Aaron Moulin
- Sanofi Biotherapeutics, Framingham, Massachusetts, USA
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11
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Good AC, Liu J, Hirth B, Asmussen G, Xiang Y, Biemann HP, Bishop KA, Fremgen T, Fitzgerald M, Gladysheva T, Jain A, Jancsics K, Metz M, Papoulis A, Skerlj R, Stepp JD, Wei RR. Implications of Promiscuous Pim-1 Kinase Fragment Inhibitor Hydrophobic Interactions for Fragment-Based Drug Design. J Med Chem 2012; 55:2641-8. [DOI: 10.1021/jm2014698] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | | | | | | | - Kimberly A. Bishop
- Department of Therapeutic Protein Discovery, Genzyme Corp., 49 New York Ave., Framingham, Massachusetts
01701, United States
| | | | | | | | - Annuradha Jain
- Department of Therapeutic Protein Discovery, Genzyme Corp., 49 New York Ave., Framingham, Massachusetts
01701, United States
| | | | | | | | | | | | - Ronnie R. Wei
- Department of Therapeutic Protein
Research, Genzyme Corp., 1 Mountain Road,
Framingham, Massachusetts 01701, United States
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12
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Xiang Y, Hirth B, Asmussen G, Biemann HP, Bishop KA, Good A, Fitzgerald M, Gladysheva T, Jain A, Jancsics K, Liu J, Metz M, Papoulis A, Skerlj R, Stepp JD, Wei RR. The discovery of novel benzofuran-2-carboxylic acids as potent Pim-1 inhibitors. Bioorg Med Chem Lett 2011; 21:3050-6. [DOI: 10.1016/j.bmcl.2011.03.030] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 03/07/2011] [Accepted: 03/09/2011] [Indexed: 11/27/2022]
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13
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Cho US, Corbett KD, Al-Bassam J, Bellizzi JJ, De Wulf P, Espelin CW, Miranda JJ, Simons K, Wei RR, Sorger PK, Harrison SC. Molecular structures and interactions in the yeast kinetochore. Cold Spring Harb Symp Quant Biol 2011; 75:395-401. [PMID: 21467141 DOI: 10.1101/sqb.2010.75.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Kinetochores are the elaborate protein assemblies that attach chromosomes to spindle microtubules in mitosis and meiosis. The kinetochores of point-centromere yeast appear to represent an elementary module, which repeats a number of times in kinetochores assembled on regional centromeres. Structural analyses of the discrete protein subcomplexes that make up the budding-yeast kinetochore have begun to reveal principles of kinetochore architecture and to uncover molecular mechanisms underlying functions such as transmission of tension and establishment and maintenance of bipolar attachment. The centromeric DNA is probably wrapped into a compact organization, not only by a conserved, centromeric nucleosome, but also by interactions among various other DNA-bound kinetochore components. The rod-like, heterotetrameric Ndc80 complex, roughly 600 Å long, appears to extend from the DNA-proximal assembly to the plus end of a microtubule, to which one end of the complex is known to bind. Ongoing structural studies will clarify the roles of a number of other well-defined complexes.
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Affiliation(s)
- U-S Cho
- Jack and Eileen Connors Structural Biology Laboratory, Harvard Medical School, Boston, Massachusetts 02115, USA
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14
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Wei RR, Hughes H, Boucher S, Bird JJ, Guziewicz N, Van Patten SM, Qiu H, Pan CQ, Edmunds T. X-ray and biochemical analysis of N370S mutant human acid β-glucosidase. J Biol Chem 2010; 286:299-308. [PMID: 20980263 DOI: 10.1074/jbc.m110.150433] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Gaucher disease is caused by mutations in the enzyme acid β-glucosidase (GCase), the most common of which is the substitution of serine for asparagine at residue 370 (N370S). To characterize the nature of this mutation, we expressed human N370S GCase in insect cells and compared the x-ray structure and biochemical properties of the purified protein with that of the recombinant human GCase (imiglucerase, Cerezyme®). The x-ray structure of N370S mutant acid β-glucosidase at acidic and neutral pH values indicates that the overall folding of the N370S mutant is identical to that of recombinant GCase. Subtle differences were observed in the conformation of a flexible loop at the active site and in the hydrogen bonding ability of aromatic residues on this loop with residue 370 and the catalytic residues Glu-235 and Glu-340. Circular dichroism spectroscopy showed a pH-dependent change in the environment of tryptophan residues in imiglucerase that is absent in N370S GCase. The mutant protein was catalytically deficient with reduced V(max) and increased K(m) values for the substrate p-nitrophenyl-β-D-glucopyranoside and reduced sensitivity to competitive inhibitors. N370S GCase was more stable to thermal denaturation and had an increased lysosomal half-life compared with imiglucerase following uptake into macrophages. The competitive inhibitor N-(n-nonyl)deoxynojirimycin increased lysosomal levels of both N370S and imiglucerase 2-3-fold by reducing lysosomal degradation. Overall, these data indicate that the N370S mutation results in a normally folded but less flexible protein with reduced catalytic activity compared with imiglucerase.
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Affiliation(s)
- Ronnie R Wei
- Genzyme Corp., Framingham, Massachusetts 01701, USA.
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15
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Powers AF, Franck AD, Gestaut DR, Cooper J, Gracyzk B, Wei RR, Wordeman L, Davis TN, Asbury CL. The Ndc80 kinetochore complex forms load-bearing attachments to dynamic microtubule tips via biased diffusion. Cell 2009; 136:865-75. [PMID: 19269365 DOI: 10.1016/j.cell.2008.12.045] [Citation(s) in RCA: 220] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 10/29/2008] [Accepted: 12/30/2008] [Indexed: 11/30/2022]
Abstract
Kinetochores couple chromosomes to the assembling and disassembling tips of microtubules, a dynamic behavior that is fundamental to mitosis in all eukaryotes but poorly understood. Genetic, biochemical, and structural studies implicate the Ndc80 complex as a direct point of contact between kinetochores and microtubules, but these approaches provide only a static view. Here, using techniques for manipulating and tracking individual molecules in vitro, we demonstrate that the Ndc80 complex is capable of forming the dynamic, load-bearing attachments to assembling and disassembling tips required for coupling in vivo. We also establish that Ndc80-based coupling likely occurs through a biased diffusion mechanism and that this activity is conserved from yeast to humans. Our findings demonstrate how an ensemble of Ndc80 complexes may provide the combination of plasticity and strength that allows kinetochores to maintain load-bearing tip attachments during both microtubule assembly and disassembly.
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Affiliation(s)
- Andrew F Powers
- Department of Physiology and Biophysics, University of Washington, Seattle, 98195, USA
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16
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Franck AD, Powers AF, Gestaut DR, Cooper J, Gracyzk B, Wei RR, Wordeman L, Davis TN, Asbury CL. Reconstitution Of Microtubule-driven Movement and Force Production by the Ndc80 Kinetochore Complex. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.3744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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17
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Larsen NA, Al-Bassam J, Wei RR, Harrison SC. Structural analysis of Bub3 interactions in the mitotic spindle checkpoint. Proc Natl Acad Sci U S A 2007; 104:1201-6. [PMID: 17227844 PMCID: PMC1770893 DOI: 10.1073/pnas.0610358104] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Indexed: 11/18/2022] Open
Abstract
The Mad3/BubR1, Mad2, Bub1, and Bub3 proteins are gatekeepers for the transition from metaphase to anaphase. Mad3 from Saccharomyces cerevisiae has homology to Bub1 but lacks a corresponding C-terminal kinase domain. Mad3 forms a stable heterodimer with Bub3. Negative-stain electron microscopy shows that Mad3 is an extended molecule (approximately 200 A long), whereas Bub3 is globular. The Gle2-binding-sequence (GLEBS) motifs found in Mad3 and Bub1 are necessary and sufficient for interaction with Bub3. The calorimetrically determined dissociation constants for GLEBS-motif peptides and Bub3 are approximately 5 microM. Crystal structures of these peptides with Bub3 show that the interactions for Mad3 and Bub1 are similar and mutually exclusive. In both structures, the GLEBS peptide snakes along the top surface of the beta-propeller, forming an extensive interface. Mutations in either protein that disrupt the interface cause checkpoint deficiency and chromosome instability. We propose that the structure imposed on the GLEBS segment by its association with Bub3 enables recruitment to unattached kinetochores.
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Affiliation(s)
| | | | - Ronnie R. Wei
- *Jack Eileen Connors Structural Biology Laboratory, and
- Howard Hughes Medical Institute, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115
| | - Stephen C. Harrison
- *Jack Eileen Connors Structural Biology Laboratory, and
- Howard Hughes Medical Institute, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115
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18
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Wei RR, Al-Bassam J, Harrison SC. The Ndc80/HEC1 complex is a contact point for kinetochore-microtubule attachment. Nat Struct Mol Biol 2006; 14:54-9. [PMID: 17195848 DOI: 10.1038/nsmb1186] [Citation(s) in RCA: 254] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2006] [Accepted: 12/01/2006] [Indexed: 11/08/2022]
Abstract
Kinetochores are multicomponent assemblies that connect chromosomal centromeres to mitotic-spindle microtubules. The Ndc80 complex is an essential core element of kinetochores, conserved from yeast to humans. It is a rod-like assembly of four proteins- Ndc80p (HEC1 in humans), Nuf2p, Spc24p and Spc25p. We describe here the crystal structure of the most conserved region of HEC1, which lies at one end of the rod and near the N terminus of the polypeptide chain. It folds into a calponin-homology domain, resembling the microtubule-binding domain of the plus-end-associated protein EB1. We show that an Ndc80p-Nuf2p heterodimer binds microtubules in vitro. The less conserved, N-terminal segment of Ndc80p contributes to the interaction and may be a crucial regulatory element. We propose that the Ndc80 complex forms a direct link between kinetochore core components and spindle microtubules.
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Affiliation(s)
- Ronnie R Wei
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, Massachusetts 02115, USA
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19
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Wei RR, Schnell JR, Larsen NA, Sorger PK, Chou JJ, Harrison SC. Structure of a central component of the yeast kinetochore: the Spc24p/Spc25p globular domain. Structure 2006; 14:1003-9. [PMID: 16765893 DOI: 10.1016/j.str.2006.04.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 04/28/2006] [Accepted: 04/28/2006] [Indexed: 11/16/2022]
Abstract
The Ndc80 complex, a kinetochore component conserved from yeast to humans, is essential for proper chromosome alignment and segregation during mitosis. It is an approximately 570 A long, rod-shaped assembly of four proteins--Ndc80p (Hec1), Nuf2p, Spc24p, and Spc25p--with globular regions at either end of a central shaft. The complex bridges from the centromere-proximal inner kinetochore layer at its Spc24/Spc25 globular end to the microtubule binding outer kinetochore layer at its Ndc80/Nuf2 globular end. We report the atomic structures of the Spc24/Spc25 globular domain, determined both by X-ray crystallography at 1.9 A resolution and by NMR. Spc24 and Spc25 fold tightly together into a single globular entity with pseudo-2-fold symmetry. Conserved residues line a common hydrophobic core and the bottom of a cleft, indicating that the functional orthologs from other eukaryotes will have the same structure and suggesting a docking site for components of the inner kinetochore.
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Affiliation(s)
- Ronnie R Wei
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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20
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Abstract
The four-protein Ndc80 complex, an essential kinetochore component conserved from yeast to humans, plays an indispensable role in proper chromosome alignment and segregation during mitosis. In higher eukaryotes, the homologous complex probably resides in the middle domain of the trilaminar kinetochore, linking centromeric heterochromatin with microtubule-associated structures. We have prepared recombinant Ndc80 complex by pairwise coexpression of its components (Ndc80p and Nuf2p; Spc24p and Spc25p) and shown that they form independently stable subcomplexes. Rotary shadowing electron microscopy, combined with limited proteolysis and antibody labeling, demonstrates that the heterotetrameric Ndc80 complex is an approximately 570-A-long rod, with globular regions at either end. The shaft contains alpha-helical coiled-coil segments from each of the two subcomplexes, linked end-to-end. When integrated with published observations derived from inactivating the components of Ndc80, the molecular organization we deduce suggests that the Spc24p/Spc25p end of the rod faces the centromere and the Ndc80p/Nuf2p end faces a spindle microtubule.
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Affiliation(s)
- Ronnie R Wei
- Department of Biological Chemistry and Molecular Pharmacology, and Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
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21
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Wei RR, Richardson JP. Mutational changes of conserved residues in the Q-loop region of transcription factor Rho greatly reduce secondary site RNA-binding. J Mol Biol 2001; 314:1007-15. [PMID: 11743718 DOI: 10.1006/jmbi.2000.5207] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Transcription factor Rho of Eschericia coli is a ring-shaped homohexameric protein that terminates transcripts by its action on nascent RNAs. To test the functional importance of the phylogenetically highly conserved residues of the Q-loop region, four mutant Rho proteins, S281A, K283A, T286A and D290A, were isolated and analyzed for their biochemical properties. All four proteins were very defective in terminating transcripts in vitro at the bacteriophage lambda tR1 terminator and had corresponding defects in ATP hydrolysis activated by lambda cro RNA. Although the four proteins were normal or near normal in their sensitivity to cleavage with H(2)O(2) in the presence of Fe-EDTA and in their ability to bind to lambda cro RNA and ATP, they were defective in RNA-specific, secondary site interactions. This was indicated by the lack of protection from cleavage at their Q-loops by oligo(C) in the presence of poly(dC), and their defects in ATP hydrolysis activated by oligo(C) in the presence of poly(dC). This evidence, together with the observations that cleavage of the Q-loop residues is protected specifically by RNA, suggests that the Q-loop makes interactions with RNA that are essential for activation of ATP hydrolysis and the termination of transcription.
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Affiliation(s)
- R R Wei
- Departments of Biology, Indiana University, Bloomington, 47405, USA
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22
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Wei RR, Richardson JP. Identification of an RNA-binding Site in the ATP binding domain of Escherichia coli Rho by H2O2/Fe-EDTA cleavage protection studies. J Biol Chem 2001; 276:28380-7. [PMID: 11369775 DOI: 10.1074/jbc.m102444200] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transcription factor Rho is a ring-shaped, homohexameric protein that causes transcript termination through actions on nascent RNAs that are coupled to ATP hydrolysis. The Rho polypeptide has a distinct RNA binding domain of known structure as well as an ATP binding domain for which a structure has been proposed based on homology modeling. Treatment of Rho with H2O2 in the presence of Fe-EDTA caused single-cut cleavage at a number of points that coincide with solvent-exposed loops in both the known and predicted structures, thereby providing support for the validity of the tertiary and quaternary structural models of Rho. The binding of ATP caused one distinct change in the cleavage pattern, a strong protection at a cleavage point in the P-loop of the ATP binding domain. Binding of RNA and single-stranded DNA (poly(dC)) caused strong protection at several accessible parts of the oligosaccharide/oligonucleotide binding (OB) fold in the RNA binding domain. RNA molecules but not DNA molecules also caused a strong, ATP-dependent protection at a cleavage site in the predicted Q-loop of the ATP binding domain. These results suggest that Rho has two distinct binding sites for RNA. Besides the site composed of multiples of the RNA binding domain, to which single-stranded DNA as well as RNA can bind, it has a separate, RNA-specific site on the Q-loop in the ATP binding domain. In the proposed quaternary structure of Rho, the Q-loops from the six subunits form the upper entrance to the hole in the ring-shaped hexamer through which the nascent transcript is translocated by actions coupled to ATP hydrolyses.
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Affiliation(s)
- R R Wei
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
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23
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Abstract
The purpose of the present study was to determine beta-carotene uptake and resultant effects on intracellular levels of retinol in cell lines of varied origin. Human skin fibroblasts, mouse embryonic fibroblasts, rabbit corneal epithelial cells, and rat liver cells were studied. Cells were cultured in medium supplemented with beta-carotene in a water-dispersible beadlet formulation. At selected intervals, cells and media were sampled and analyzed by high-performance liquid chromatography for beta-carotene and retinol content. beta-Carotene was taken up by all four cell lines. An increase in the intracellular levels of retinol was concomitant with beta-carotene uptake in all cell lines. The uptake of beta-carotene and the increase in intracellular retinol were highest in the two fibroblast cell lines. Incubation with media supplemented with crystalline beta-carotene, dissolved in tetrahydrofuran, resulted in significantly lower beta-carotene uptake and intracellular retinol levels. We view these results as a demonstration that a wide variety of cells, cultured in vitro, are able to convert beta-carotene to retinol. Therefore, beta-carotene's provitamin A activity should be carefully considered when the protective effects of beta-carotene in vitro are interpreted.
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Affiliation(s)
- R R Wei
- Center for Food Safety and Applied Nutrition, US Food and Drug Administration, Washington, DC 20204, USA
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24
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Turujman SA, Wamer WG, Wei RR, Albert RH. Rapid liquid chromatographic method to distinguish wild salmon from aquacultured salmon fed synthetic astaxanthin. J AOAC Int 1997; 80:622-32. [PMID: 9170658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Analytical methods are needed to determine the presence of color additives in fish. We report a liquid chromatographic (LC) method developed to identify the synthetic form of the color additive astaxanthin in salmon, based on differences in the relative ratios of the configurational isomers of astaxanthin. The distributions of configurational isomers of astaxanthin in the flesh of wild Atlantic and wild Pacific salmon are similar, but significantly different from that in aquacultured salmon. Astaxanthin is extracted from the flesh of salmon, passed through a silica gel Sep-Pak cartridge, and analyzed directly by LC on a Pirkle covalent L-leucine column. No derivatization of the astaxanthin is required-an important advantage of our approach, which is a modification of our previously described method. This method can be used to distinguish between aquacultured and wild salmon. The method has general applicability and can also be used to identify astaxanthins derived from other sources such as Phaffia yeast and Haematococcus pluvialis algae.
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Affiliation(s)
- S A Turujman
- U.S. Food and Drug Administration, Office of Cosmetics and Colors, Washington, DC 20204, USA
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25
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Abstract
Although ultraviolet A radiation (UVA, 315-400 nm) has been shown to induce oxidative stress in mammalian cells and skin, the critical chromophore(s) and molecular target(s) involved have not been identified. We examined the role of oxidative damage to nucleic acids induced by UVA. To assess photooxidation of cellular DNA and RNA by UVA, we irradiated human skin fibroblasts with up to 765 kJ/m2 UVA. Cellular DNA and RNA were isolated immediately and enzymatically hydrolyzed to nucleosides. 8-Oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), a primary oxidation product in DNA, and 8-oxo-7,8-dihydroguanosine (8-oxoG), resulting from hydroxylation of guanine in RNA, were measured by HPLC with electrochemical detection. We determined that irradiation of skin fibroblasts with levels of UVA that produced moderate toxicity also resulted in significant levels of guanine hydroxylation in RNA. Lower levels of photooxidation were observed in DNA. These results suggest that measurement of guanine hydroxylation in nucleic acids, particularly in cellular RNA, may be a powerful tool for investigating the photobiological activity of UVA.
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Affiliation(s)
- W G Wamer
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Washington, DC, USA
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26
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Abstract
The semiconductor TiO2 is known to have photobiological activity in prokaryotic and eukaryotic cells. Applications of this photobiological activity have been suggested including sterilization of waste water and phototherapy of malignant cells. Here, several model and cellular systems were used to study the mechanism of photocatalysis by TiO2. Treatment of TiO2 (anatase, 0.45 microns), suspended in water containing a spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), with UV radiation (320 nm) resulted in an electron spin resonance (ESR) signal characteristic of the hydroxyl radical. Irradiation of solutions containing calf thymus DNA and TiO2 with UVA (320-400 nm) radiation resulted in hydroxylation of guanine bases. The degree of hydroxylation was dependent on both UVA fluence and amount of TiO2 in suspension. Human skin fibroblasts, preincubated 18 h with 10 micrograms/cm2 TiO2 and then UVA-irradiated (0-58 KJ/m2), showed dose dependent photocytoxicity. RNA, isolated from similarly treated fibroblasts, contained significant levels of photooxidation, measured as hydroxylation of guanine bases. However, no oxidative damage was detectable in cellular DNA. These results suggest that nucleic acids are a potential target for photooxidative damage sensitized by TiO2, and support the view that TiO2 photocatalyzes free radical formation.
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Affiliation(s)
- W G Wamer
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Washington, DC 20204, USA.
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27
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Abstract
Guanosine hydroxylation was used as a marker for assessing photooxidation of DNA and RNA sensitized by monofunctional and bifunctional furocoumarins. DNA or RNA, treated with sensitizer and UVA light, was enzymatically hydrolyzed, dephosphorylated and then analyzed by reversed-phase HPLC with electrochemical detection. Hydroxylated guanosine, i.e. 8-hydroxy-2'-deoxyguanosine (8-OHdG) or 8-hydroxyguanosine (8-OHG), was quantitated. 3-Carbethoxypsoralen (3-CP) was found to be an efficient photosensitizer for oxidation of guanosine in DNA, resulting in conversion of up to 0.4% of guanosine residues to 8-OHdG. In contrast, dramatically lower levels of guanosine hydroxylation were observed in 3-CP-photosensitized RNA. Psoralen was found to be a more efficient photosensitizer than angelicin in both DNA and RNA. Additional studies of oxidation of 3-CP-photosensitized DNA indicated that double-stranded DNA is 10 times more susceptible to photooxidation than single-stranded DNA, implicating 3-CP binding to DNA as an important mechanistic step in photooxidation of guanosine. The effects of D2O and degassing with argon on photooxidation of guanosine in DNA sensitized by 3-CP were inconsistent with a mechanism involving 1O2. In addition, chelation of adventitious metal ions present in preparations of DNA photosensitized by 3-CP had no effect on hydroxylation of guanosine.
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Affiliation(s)
- W G Wamer
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Washington, DC 20204, USA
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28
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Abstract
In the past several years there has been a great deal of interest in the antioxidant beta-carotene and other micronutrients for their protective potential against various toxic insults. Two studies concerning the protective effects of beta-carotene, which were conducted in our laboratory, are reported here. The first involved the role of beta-carotene in modifying two-stage skin tumorigenesis initiated by 7,12-dimethylbenz[a]anthracene (DMBA) and promoted by phorbol 12-myristate 13-acetate (PMA, TPA). In this study, the protective effects of two types of dietary beta-carotene, a beadlet formulation and crystalline beta-carotene, were compared in two strains of mice (Skh:HR-1 and CR:ORL Sencar). Mice were maintained on food fortified with 3% beta-carotene or on control diets. Mice receiving the beta-carotene-supplemented diets had fewer tumours than mice in the control groups. However, only in the Skh strain of mice was this difference statistically significant. In the second study, an in vitro experiment, BALBc 3T3 mouse fibroblasts were used to determine beta-carotene's accumulation in cells and the ability of these cells to metabolize beta-carotene to vitamin A. This in vitro model was also used to show a beta-carotene protective effect towards 8-MOP phototoxicity. These studies contributed to the increasing evidence of in vivo and in vitro protection by beta-carotene against chemically induced toxicity.
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Affiliation(s)
- A Kornhauser
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, Washington, DC 20204
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Lambert LA, Wamer WG, Wei RR, Lavu S, Chirtel SJ, Kornhauser A. The protective but nonsynergistic effect of dietary beta-carotene and vitamin E on skin tumorigenesis in Skh mice. Nutr Cancer 1994; 21:1-12. [PMID: 8183718 DOI: 10.1080/01635589409514299] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Various epidemiological and experimental studies have indicated that beta-carotene and vitamin E protect against a variety of cancers. This investigation determined whether a synergistic protective effect could be observed against chemically induced skin tumorigenesis in Skh mice by combining these two antioxidants in the diet. Forty-five mice were used in each of four diet groups. Control animals were fed standard mouse chow. Three other groups received the chow supplemented with one of the following: 0.5% beta-carotene, 0.12% vitamin E (added as d-alpha-tocopheryl succinate), or 0.5% beta-carotene + 0.12% vitamin E. Mice were topically treated with a single application of the initiator 7,12-dimethylbenz[a]anthracene and promoted with multiple applications of phorbol 12-myristate 13-acetate. Mice were observed for tumors each week for 27 weeks after initiation. The protective effect of each diet was determined by the decrease in the number of skin tumors in supplemented diet groups compared with that of the control diet group. Decreases in the number of cumulative tumors at Week 27 were 32% for beta-carotene-, 25% for vitamin E-, and 21% for beta-carotene+vitamin E-supplemented diet groups. However, differences in the number of tumors among the three groups supplemented with beta-carotene and/or vitamin E were not statistically significant. Thus, although protection was provided by the individual supplements, there was no synergistic effect for a decrease in the number of chemically induced skin tumors by the simultaneous dietary administration of beta-carotene and vitamin E.
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Affiliation(s)
- L A Lambert
- Cosmetics Toxicology Branch, U.S. Food and Drug Administration, Washington, DC 20204
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30
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Affiliation(s)
- W G Wamer
- Food and Drug Administration, Center for Food Safety and Applied Nutrition, Washington, DC 20204
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31
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Lambert LA, Wamer WG, Wei RR, Lavu S, Kornhauser A. The absence of a synergistic protective effect of beta-carotene and vitamin E on skin tumorigenesis in mice. Ann N Y Acad Sci 1993; 691:259-61. [PMID: 8129306 DOI: 10.1111/j.1749-6632.1993.tb26188.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- L A Lambert
- US Food and Drug Administration, Center for Food Safety and Applied Nutrition, Washington, DC 20204
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32
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Abstract
Although a growing number of epidemiological studies indicate that dietary beta-carotene has anticarcinogenic activity, the mechanism(s) of beta-carotene protection remains to be definitively established. In this context, in vitro studies of beta-carotene have been, and continue to be, valuable. We examined the following critical features in designing an in vitro system for studying the protection action of beta-carotene: 1) form of beta-carotene used for cellular uptake, 2) cellular metabolism of beta-carotene, and 3) subcellular distribution of beta-carotene. It was determined that beta-carotene added to medium in a water-dispersible formulation is readily taken up by BALB/c 3T3 cells and is located predominantly in cellular membranes. Cellular uptake of beta-carotene added to medium in an organic solvent is greatly reduced. It was also found that intracellular retinol increased significantly after a three-day exposure of BALB/c 3T3 cells to media containing beta-carotene. This result suggests that the ability to metabolize beta-carotene to retinoids is not limited to cells of intestinal origin. The results and methodology described here will be useful in the rational design of in vitro assays for elucidating the mechanism(s) of beta-carotene protective effects at the cellular level.
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Affiliation(s)
- W G Wamer
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Washington, DC 20204
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