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Caccuri F, Iaria ML, Campilongo F, Varney K, Rossi A, Mitola S, Schiarea S, Bugatti A, Mazzuca P, Giagulli C, Fiorentini S, Lu W, Salmona M, Caruso A. Cellular aspartyl proteases promote the unconventional secretion of biologically active HIV-1 matrix protein p17. Sci Rep 2016; 6:38027. [PMID: 27905556 PMCID: PMC5131311 DOI: 10.1038/srep38027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 11/03/2016] [Indexed: 11/24/2022] Open
Abstract
The human immune deficiency virus type 1 (HIV-1) matrix protein p17 (p17), although devoid of a signal sequence, is released by infected cells and detected in blood and in different organs and tissues even in HIV-1-infected patients undergoing successful combined antiretroviral therapy (cART). Extracellularly, p17 deregulates the function of different cells involved in AIDS pathogenesis. The mechanism of p17 secretion, particularly during HIV-1 latency, still remains to be elucidated. A recent study showed that HIV-1-infected cells can produce Gag without spreading infection in a model of viral latency. Here we show that in Gag-expressing cells, secretion of biologically active p17 takes place at the plasma membrane and occurs following its interaction with phosphatidylinositol-(4,5)-bisphosphate and its subsequent cleavage from the precursor Gag (Pr55Gag) operated by cellular aspartyl proteases. These enzymes operate a more complex Gag polypeptide proteolysis than the HIV-1 protease, thus hypothetically generating slightly truncated or elongated p17s in their C-terminus. A 17 C-terminal residues excised p17 was found to be structurally and functionally identical to the full-length p17 demonstrating that the final C-terminal region of p17 is irrelevant for the protein’s biological activity. These findings offer new opportunities to identify treatment strategies for inhibiting p17 release in the extracellular microenvironment.
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Affiliation(s)
- Francesca Caccuri
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Maria Luisa Iaria
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Federica Campilongo
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Kristen Varney
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Alessandro Rossi
- IRCCS Istituto di Ricerche Farmacologiche "Mario Negri" Milan, Italy
| | - Stefania Mitola
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Silvia Schiarea
- IRCCS Istituto di Ricerche Farmacologiche "Mario Negri" Milan, Italy
| | - Antonella Bugatti
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Pietro Mazzuca
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Cinzia Giagulli
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Simona Fiorentini
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
| | - Wuyuan Lu
- Institute of Human Virology, University of Maryland, Baltimore, Maryland, USA
| | - Mario Salmona
- IRCCS Istituto di Ricerche Farmacologiche "Mario Negri" Milan, Italy
| | - Arnaldo Caruso
- Department of Molecular and Translational Medicine, University of Brescia Medical School, Brescia, Italy
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Golynskiy MV, Rurup WF, Merkx M. Antibody detection by using a FRET-based protein conformational switch. Chembiochem 2011; 11:2264-7. [PMID: 20928879 DOI: 10.1002/cbic.201000143] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Misha V Golynskiy
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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Correlating low-similarity peptide sequences and HIV B-cell epitopes. Autoimmun Rev 2008; 7:291-6. [DOI: 10.1016/j.autrev.2007.11.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Accepted: 11/06/2007] [Indexed: 11/20/2022]
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Ota A, Tanaka-Taya K, Ueda S. Cross-reactivity of anti-HIV-1-p17-derivative peptide (P30-52) antibody to Env V3 peptide. Hybridoma (Larchmt) 1999; 18:149-57. [PMID: 10380014 DOI: 10.1089/hyb.1999.18.149] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Strong antibody responses are often seen in human immunodeficiency virus type 1 (HIV-1) carriers, but it is not known whether these antibodies are effective in the inhibition of disease progression. In this study, we examined antigenic epitopes for anti-HIV-1 p17 antibody (p17 Ab) in an HIV-1 carrier's serum, and found that the residues of amino acid numbers 1 to 12 (P1-12), 12 to 29 (P12-29) and 30 to 52 (P30-52) of p17 were highly recognized in the serum. Our examination of purified antibodies from the patient using the p17-derivative-peptide-immunoaffinity columns showed that the reactivity of anti-p30-52 Ab (p30-52Ab) was high for p30-52 and the naive protein, p17. In addition, this P30-52Ab cross-reacted with the third variable region of the envelope glycoprotein (Env V3). To confirm this cross-reactivity, we immunized mice with P30-52, and established a monoclonal antibody (MAb), 8H10. We found that 8H10 was also reactive to Env V3. It is unclear whether this cross-reactivity of P30-52 Ab can function as the inhibitor of HIV-1, but these results will be of help in clarifying the interaction of Env protein with HIV-1 gag polyprotein and the relationship of the decline of the p17 antibody titer with the disease progression in HIV-1 carriers.
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Affiliation(s)
- A Ota
- Department of Neurovirology, Research Institute for Microbial Diseases, Osaka University, Suita City, Japan
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Ota A, Bautista AN, Yadav ML, Ueda S. Anti-P30-52 monoclonal antibody cross-reacted to Env V3 and inhibited the viral multiplication of HIV-1-infected MT-4 cells. Hybridoma (Larchmt) 1999; 18:139-47. [PMID: 10380013 DOI: 10.1089/hyb.1999.18.139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
It is well known that the anti-p17 antibody titer decreases with the disease progression among human immunodeficiency virus type 1 (HIV-1) carriers. We previously established several murine anti-p17 monoclonal antibodies (MAbs) to investigate the immunological role of p17, and to further characterize these MAbs, we examined the anti-p17 antibody titer in serum of a patient who was a long-term nonprogressor with hemophilia, and found that the antibody for the p17-derivative peptide from amino acid residues 30 to 52 (P30-52) cross-reacted to the third variable region of the envelope glycoprotein of HIV-1, Env V3. In the present study, we primed mice with P30-52 to establish anti-P30-52 MAbs (P30-52 MAbs), and examined their affinity and whether they suppressed the viral multiplication of HIV-1-infected MT-4 (HTLV-1-transformed CD4+ T-cell line) cells, in a TCID50 assay. At the same time, an anti-Env V3 MAb (Env V3 MAb) was also established and examined as above. The IgM-type P30-52 MAb and Env V3 MAb showed heteroclitic binding, and the IgM-type P30-52 MAb inhibited the viral multiplication. We also found that an increase of fragmented DNA of HIV-1-infected MT-4 cells co-cultured with P30-52 MAbs. Because DNA fragmentation is one of the features of programmed cell death, the viral multiplication may be suppressed by the apoptosis of HIV-1-infected MT-4 cells co-cultured with P30-52 MAbs. Though the relationship between cross-reactivity and the inhibition mechanism of multiplication of HIV-1 is unclear, P30-52 of p17 may well be a useful region of viral proteins for the development of therapeutic and vaccination strategies.
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Affiliation(s)
- A Ota
- Department of Neurovirology, Research Institute for Microbial Diseases, Osaka University, Suita City, Japan
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HyHIV1-6: A recombinant pl7 protein of HIV-1. Hybridoma (Larchmt) 1998. [DOI: 10.1089/hyb.1998.17.489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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HyHIV21: A recombinant p17 protein. Hybridoma (Larchmt) 1998. [DOI: 10.1089/hyb.1998.17.222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ota A, Liu X, Fujio H, Sakato N, Ueda S. Random expression of human immunodeficiency virus-1 (HIV-1) p17 (epitopes) on the surface of the HIV-1-infected cell. Hybridoma (Larchmt) 1998; 17:73-5. [PMID: 9523241 DOI: 10.1089/hyb.1998.17.73] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Twenty monoclonal antibodies (MAbs) were obtained by immunizing Balb/c mice with recombinant p17 (rp17) of HIV-1. Epitope specificity of each MAb was determined using six peptides that cover the entire region of p17. We found that each MAb reacts with only one of the peptides, residues 12-29, 30-52, 53-87, and 87-115 (P12-29, P30-52, P53-87, P87-115) of p17 with the exception of one MAb. Three kinds of MAbs that recognize P30-52, P87-115, and a conformational epitope, suppressed the infectivity of HIV-1 (JMH-1) when they added in the culture of MT-4 cells infected by HIV-1 within 24 h of the infection.
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Affiliation(s)
- A Ota
- Department of Neurovirology, Osaka University, Suita, Japan
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Buratti E, Tisminetzky SG, D'Agaro P, Baralle FE. A neutralizing monoclonal antibody previously mapped exclusively on human immunodeficiency virus type 1 gp41 recognizes an epitope in p17 sharing the core sequence IEEE. J Virol 1997; 71:2457-62. [PMID: 9032383 PMCID: PMC191356 DOI: 10.1128/jvi.71.3.2457-2462.1997] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We report here that a human immunodeficiency virus type 1 (HIV-1)-specific neutralizing monoclonal antibody (MAb 1575) mapped to the conserved putative intracellular region from amino acid residues 735 to 752 (735-752 region) of gp41 also recognizes a region in an extracellular portion of p17. Both epitopes have a core recognition sequence (IEEE) in a nonhomologous context. The IEEE motif found in HIV-1 p17 is located in a region known as HGP-30 (residues 86 to 115) which has been previously associated with virus neutralization, cytotoxic T lymphocyte activity, and mother-to-child transmission. An analysis of available gp41 and p17 sequences demonstrates that in these regions both IEEE sequences are highly conserved in different HIV-1 clades. The presence of the IEEE epitope in p17 allows us to explain some unexpected neutralizing characteristics of MAb 1575. In addition, the gp41 735-752 region has been previously reported both in intra- and extracellular locations. Our results suggest that the extracellular location was the result of cross-reactivity with p17.
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Affiliation(s)
- E Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
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