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Wang Y, Xu J, Huang F, Yan J, Fan X, Zou Y, Wang C, Ding F, Sun Y. SEVI Inhibits Aβ Amyloid Aggregation by Capping the β-Sheet Elongation Edges. J Chem Inf Model 2023; 63:3567-3578. [PMID: 37246935 PMCID: PMC10363411 DOI: 10.1021/acs.jcim.3c00414] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Inhibiting the aggregation of amyloid peptides with endogenous peptides has broad interest due to their intrinsically high biocompatibility and low immunogenicity. Here, we investigated the inhibition mechanism of the prostatic acidic phosphatase fragment SEVI (semen-derived enhancer of viral infection) against Aβ42 fibrillization using atomistic discrete molecular dynamic simulations. Our result revealed that SEVI was intrinsically disordered with dynamic formation of residual helices. With a high positive net charge, the self-aggregation tendency of SEVI was weak. Aβ42 had a strong aggregation propensity by readily self-assembling into β-sheet-rich aggregates. SEVI preferred to interact with Aβ42, rather than SEVI themselves. In the heteroaggregates, Aβ42 mainly adopted β-sheets buried inside and capped by SEVI in the outer layer. SEVI could bind to various Aβ aggregation species─including monomers, dimers, and proto-fibrils─by capping the exposed β-sheet elongation edges. The aggregation processes Aβ42 from the formation of oligomers to conformational nucleation into fibrils and fibril growth should be inhibited as their β-sheet elongation edges are being occupied by the highly charged SEVI. Overall, our computational study uncovered the molecular mechanism of experimentally observed inhibition of SEVI against Aβ42 aggregation, providing novel insights into the development of therapeutic strategies against Alzheimer's disease.
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Affiliation(s)
- Ying Wang
- School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
- Ningbo Institute of Innovation for Combined Medicine and Engineering (NIIME), Ningbo Medical Center Lihuili Hospital, Ningbo 315211, China
| | - Jia Xu
- School of Medicine, Ningbo University, Ningbo 315211, China
| | - Fengjuan Huang
- Ningbo Institute of Innovation for Combined Medicine and Engineering (NIIME), Ningbo Medical Center Lihuili Hospital, Ningbo 315211, China
| | - Jiajia Yan
- School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
| | - Xinjie Fan
- School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
| | - Yu Zou
- Department of Sport and Exercise Science, Zhejiang University, Hangzhou 310058, China
| | - Chuang Wang
- School of Medicine, Ningbo University, Ningbo 315211, China
| | - Feng Ding
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States
| | - Yunxiang Sun
- School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
- Ningbo Institute of Innovation for Combined Medicine and Engineering (NIIME), Ningbo Medical Center Lihuili Hospital, Ningbo 315211, China
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States
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Kusova A, Abramova M, Skvortsova P, Yulmetov A, Mukhametzyanov T, Klochkov V, Blokhin D. Structure of amyloidogenic PAP(85-120) peptide by high-resolution NMR spectroscopy. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.132294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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3
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Ivanova MI, Lin Y, Lee YH, Zheng J, Ramamoorthy A. Biophysical processes underlying cross-seeding in amyloid aggregation and implications in amyloid pathology. Biophys Chem 2020; 269:106507. [PMID: 33254009 DOI: 10.1016/j.bpc.2020.106507] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/13/2020] [Accepted: 11/13/2020] [Indexed: 12/18/2022]
Abstract
Abnormal aggregation of proteins into filamentous aggregates commonly associates with many diseases, such as Alzheimer's disease, Parkinson's disease and type-2 diabetes. These filamentous aggregates, also known as amyloids, can propagate their abnormal structures to either the same precursor molecules (seeding) or other protein monomers (cross-seeding). Cross-seeding has been implicated in the abnormal protein aggregation and has been found to facilitate the formation of physiological amyloids. It has risen to be an exciting area of research with a high volume of published reports. In this review article, we focus on the biophysical processes underlying the cross-seeding for some of the most commonly studied amyloid proteins. Here we will discuss the relevant literature related to cross-seeded polymerization of amyloid-beta, human islet amyloid polypeptide (hIAPP, or also known as amylin) and alpha-synuclein. SEVI (semen-derived enhancer of viral infection) amyloid formation by the cross-seeding between the bacterial curli protein and PAP248-286 is also briefly discussed.
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Affiliation(s)
- Magdalena I Ivanova
- Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Biophysics, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Yuxi Lin
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, Ochang, Chungbuk 28119, South Korea
| | - Young-Ho Lee
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, Ochang, Chungbuk 28119, South Korea; Bio-Analytical Science, University of Science and Technology, Daejeon 34113, South Korea; Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon 34134, South Korea; Research headquarters, Korea Brain Research Institute, Daegu 41068, South Korea
| | - Jie Zheng
- Department of Chemical and Biomolecular Engineering, The University of Akron, Ohio, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics, University of Michigan, Ann Arbor, MI 48109, USA; Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA; Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
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Kumar V, Kumar PG, Yadav JK. Impact of semen-derived amyloid (SEVI) on sperm viability and motility: its implication in male reproductive fitness. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2019; 48:659-671. [PMID: 31392382 DOI: 10.1007/s00249-019-01391-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 09/13/2018] [Accepted: 07/29/2019] [Indexed: 01/09/2023]
Abstract
Human semen contains a large number of macromolecules, including proteins/enzymes and carbohydrates, regulating and protecting sperm cells. Proteomic analysis of human seminal fluid led to the discovery of semen amyloids derived from short peptide fragments of the proteins prostatic acid phosphatase (PAP) and semenogelin (SG) which are known to play a crucial role in enhancing HIV infection. However, the relevance of their existence in human semen and role in maintaining sperm behavior remains unclear. Distinct physiological, biochemical, and biophysical attributes might cause these amyloids to influence sperm behavior positively or negatively, affecting fertilization or other reproductive processes. We assessed the direct effect of amyloids derived from a PAP248-286 fragment, on sperm motility and viability, which are crucial parameters for assessment of sperm quality in semen. Co-incubation of human sperm with PAP248-286 amyloids at normal physiological concentrations formed in buffer led to significant reduction in sperm viability, though approximately a 10× higher concentration was needed to show a similar effect with amyloid formed in seminal fluid. Both forms of PAP248-286 amyloid also had a significant impact on sperm motility at physiological levels, in agreement with a previous report. Our study suggests that PAP248-286 amyloids can directly influence sperm motility and viability in a concentration-dependent manner. We hypothesise that the direct toxic effect of PAP248-286 amyloid is normally mitigated by other seminal fluid ingredients, but that in pathological conditions, where PAP248-286 concentrations are elevated and it plays a role in determining sperm health and viability, with relevance for male fertility as well as sterility.
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Affiliation(s)
- Vijay Kumar
- Department of Biotechnology, Central University of Rajasthan, NH-8 Jaipur-Ajmer Highway, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India
| | - Pradeep G Kumar
- Molecular Reproduction Division, Rajiv Gandhi Centre for Biotechnology, Thycaud PO, Poojappura, Thiruvananthapuram, Kerala, 695014, India
| | - Jay Kant Yadav
- Department of Biotechnology, Central University of Rajasthan, NH-8 Jaipur-Ajmer Highway, Bandarsindri, Kishangarh, Ajmer, Rajasthan, 305817, India.
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Kordy K, Tobin NH, Aldrovandi GM. HIV and SIV in Body Fluids: From Breast Milk to the Genitourinary Tract. ACTA ACUST UNITED AC 2019; 15:139-152. [PMID: 33312088 DOI: 10.2174/1573395514666180605085313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
HIV-1 is present in many secretions including oral, intestinal, genital, and breast milk. However, most people exposed to HIV-1 within these mucosal compartments do not become infected despite often frequent and repetitive exposure over prolonged periods of time. In this review, we discuss what is known about the levels of cell-free HIV RNA, cell-associated HIV DNA and cell-associated HIV RNA in external secretions. Levels of virus are usually lower than contemporaneously obtained blood, increased in settings of inflammation and infection, and decreased in response to antiretroviral therapy. Additionally, each mucosal compartment has unique innate and adaptive immune responses that affect the composition and presence of HIV-1 within each external secretion. We discuss the current state of knowledge about the types and amounts of virus present in the various excretions, touch on innate and adaptive immune responses as they affect viral levels, and highlight important areas for further study.
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Affiliation(s)
- Kattayoun Kordy
- Department of Pediatrics, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
| | - Nicole H Tobin
- Department of Pediatrics, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
| | - Grace M Aldrovandi
- Department of Pediatrics, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
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Kordy K, Elliott J, Tanner K, Johnson EJ, McGowan IM, Anton PA. Human Semen or Seminal Plasma Does Not Enhance HIV-1 BaL Ex Vivo Infection of Human Colonic Explants. AIDS Res Hum Retroviruses 2018; 34:459-466. [PMID: 29343073 PMCID: PMC5934974 DOI: 10.1089/aid.2017.0118] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
To determine whether human whole semen (WS) and seminal plasma (SP) either previously frozen or freshly acquired altered ex vivo infectibility of human colonic explants or was associated with histology or toxicity changes, which may influence mucosal HIV-1 transmission in vivo. Pooled human semen samples were freshly obtained from study volunteers (never frozen) and from commercial sources (frozen/thawed). Endoscopically acquired rectal biopsies were evaluated for toxicity following titered ex vivo WS/SP exposure by histological grading and by MTT assay. The ex vivo HIV-1 biopsy challenge model was used to evaluate effects of exposure to either previously frozen or freshly acquired WS/SP on HIVBaL infectibility at a range of viral inocula (104-100 TCID50). To evaluate the effects at lower viral inocula of HIV-1 (10-2-102), experiments in the presence or absence of WS/SP were also performed utilizing TZM-bl cells. MTT assays and histological scoring demonstrated no tissue degradation of biopsies when exposed for 2 h to concentrations of 10% or 100% of either fresh or previously frozen WS/SP. Ex vivo biopsy HIV-1 challenge experiments showed no differences in the presence of freshly acquired or previously frozen/thawed WS/SP compared with control; no differences were seen with lower infectious titers on TZM-bl cells. Within the limits of assay sensitivity and variability, these data show no toxicity or significant enhancement of HIV-1 infectibility of human rectal mucosa using the colorectal explant model with either pooled fresh or frozen/thawed nonautologous human semen.
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Affiliation(s)
| | - Julie Elliott
- Department of Medicine, Center for HIV Prevention Research, UCLA AIDS Institute, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Karen Tanner
- Department of Medicine, Center for HIV Prevention Research, UCLA AIDS Institute, David Geffen School of Medicine at UCLA, Los Angeles, California
| | | | - Ian M. McGowan
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Peter A. Anton
- Department of Medicine, Center for HIV Prevention Research, UCLA AIDS Institute, David Geffen School of Medicine at UCLA, Los Angeles, California
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Lee YH, Ramamoorthy A. Semen-derived amyloidogenic peptides-Key players of HIV infection. Protein Sci 2018; 27:1151-1165. [PMID: 29493036 DOI: 10.1002/pro.3395] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 02/23/2018] [Accepted: 02/26/2018] [Indexed: 12/26/2022]
Abstract
Misfolding and amyloid aggregation of intrinsically disordered proteins (IDPs) are implicated in a variety of diseases. Studies have shown that membrane plays important roles on the formation of intermediate structures of IDPs that can initiate (and/or speed-up) amyloid aggregation to form fibers. The process of amyloid aggregation also disrupts membrane to cause cell death in amyloid diseases like Alzheimer's disease and type-2 diabetes. On the other hand, recent studies reported the membrane fusion properties of amyloid fibers. Remarkably, amyloid-fibril formation by short peptide fragments of highly abundant prostatic acidic-phosphatase (PAP) in human semen and are capable of boosting the rate of HIV infection up to 400,000-fold during sexual contact. Unlike the least toxic fully matured fibers of most amyloid proteins, the semen-derived enhancer of virus infection (SEVI) amyloid-fibrils of PAP peptide fragments are highly potent in rendering the maximum rate of HIV infection. This unusual property of amyloid fibers has witnessed increasing number of studies on the biophysical aspects of fiber formation and fiber-membrane interactions. NMR studies have reported a highly disordered partial helical structure in a membrane environment for the intrinsically disordered PAP peptide that promotes the fusion of the viral membrane with that of host cells. The purpose of this review article is to unify and integrate biophysical and immunological research reported in the previous studies on SEVI. Specifically, amyloid aggregation, dramatic HIV infection enhancing properties, membrane fusion properties, high resolution NMR structure, and approaches to eliminate the enhancement of HIV infection of SEVI peptides are discussed.
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Affiliation(s)
- Young-Ho Lee
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka, 565-0871, Japan
| | - Ayyalusamy Ramamoorthy
- Biophysics Program and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan, 48109-1055
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8
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Chen J, Ren R, Yu F, Wang C, Zhang X, Li W, Tan S, Jiang S, Liu S, Li L. A Degraded Fragment of HIV-1 Gp120 in Rat Hepatocytes Forms Fibrils and Enhances HIV-1 Infection. Biophys J 2017; 113:1425-1439. [PMID: 28978437 DOI: 10.1016/j.bpj.2017.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/03/2017] [Accepted: 08/04/2017] [Indexed: 12/26/2022] Open
Abstract
Identification of the host or viral factors that enhance HIV infection is critical for preventing sexual transmission of HIV. Amyloid fibrils derived from human semen, including semen-derived enhancer of virus infection and semenogelins, enhance HIV-1 infection dramatically in vitro. In this study, we reported that a short-degraded peptide fragment 1 (DPF1) derived from native HIV-1 envelope protein gp120-loaded rat hepatocytes, formed fibrils by self-assembly and thus enhanced HIV-1 infection by promoting the binding of HIV-1 to target cells. Furthermore, DPF1-formed fibrils might be used as a crossing seed to accelerate the formation of semen-derived enhancer of virus infection and semenogelin fibrils. It will be helpful to clarify the viral factors that affect HIV-1 infection. DPF1 as an analog of gp120 containing the critical residues for CD4 binding might be useful for designing of HIV vaccines and developing HIV entry inhibitors.
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Affiliation(s)
- Jinquan Chen
- Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key Laboratory of Drug Research for Emerging Virus Prevention and Treatment, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China; Jiangsu Protein Drug Engineering Laboratory, Jiangsu Food and Pharmaceutical Science College, Huai'an, China
| | - Ruxia Ren
- Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key Laboratory of Drug Research for Emerging Virus Prevention and Treatment, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Fei Yu
- College of Life Sciences, Agricultural University of Hebei, Baoding, China; Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Chunyan Wang
- Center for Clinical Laboratory, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xuanxuan Zhang
- Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key Laboratory of Drug Research for Emerging Virus Prevention and Treatment, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Wenjuan Li
- Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key Laboratory of Drug Research for Emerging Virus Prevention and Treatment, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Suiyi Tan
- Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key Laboratory of Drug Research for Emerging Virus Prevention and Treatment, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology of MOE/MOH, School of Basic Medical Sciences, Fudan University, Shanghai, China; Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York
| | - Shuwen Liu
- Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key Laboratory of Drug Research for Emerging Virus Prevention and Treatment, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China.
| | - Lin Li
- Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key Laboratory of Drug Research for Emerging Virus Prevention and Treatment, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China.
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9
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HIV-Enhancing and HIV-Inhibiting Properties of Cationic Peptides and Proteins. Viruses 2017; 9:v9050108. [PMID: 28505117 PMCID: PMC5454421 DOI: 10.3390/v9050108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/05/2017] [Accepted: 05/10/2017] [Indexed: 12/26/2022] Open
Abstract
Cationic antimicrobial peptides and proteins have historically been ascribed roles in innate immunity that infer killing of microbial and viral pathogens and protection of the host. In the context of sexually transmitted HIV-1, we take an unconventional approach that questions this paradigm. It is becoming increasingly apparent that many of the cationic polypeptides present in the human genital or anorectal mucosa, or human semen, are capable of enhancing HIV-1 infection, often in addition to other reported roles as viral inhibitors. We explore how the in vivo environment may select for or against the HIV-enhancing aspects of these cationic polypeptides by focusing on biological relevance. We stress that the distinction between enhancing and inhibiting HIV-1 infection is not mutually exclusive to specific classes of cationic polypeptides. Understanding how virally enhancing peptides and proteins act to promote sexual transmission of HIV-1 would be important for the design of topical microbicides, mucosal vaccines, and other preventative measures.
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10
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Qiao X, Jeon J, Cole AL, Matos JO, Bautista S, Castillo J, Hung I, Gan Z, Tatulian SA, Cole AM, Chen B. Morphology-Dependent HIV-Enhancing Effect of Semen-Derived Enhancer of Viral Infection. Biophys J 2016; 108:2028-37. [PMID: 25902442 DOI: 10.1016/j.bpj.2015.03.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 02/20/2015] [Accepted: 03/20/2015] [Indexed: 02/06/2023] Open
Abstract
PAP248-286 is a 39-residue fragment (residues 248 to 286) derived from protease cleavage of prostatic acidic phosphatase in semen. The amyloid fibrils formed in vitro by PAP248-286 can dramatically enhance human immunodeficiency virus (HIV) infection. To our knowledge, we present the first report that the HIV-enhancing potency of fibrils formed by PAP248-286 is morphology dependent. We identified pleomorphic fibrils by transmission electron microscopy in two buffer conditions. Our solid-state NMR data showed that these fibrils consist of molecules in distinct conformations. In agreement with NMR, fluorescence measurements confirmed that they are assembled along different pathways, with distinct molecular structures. Furthermore, our cell-based infectivity tests detected distinct HIV-enhancing potencies for fibrils in distinct morphologies. In addition, our transmission electron microscopy and NMR results showed that semen-derived enhancer of viral infection fibrils formed in sodium bicarbonate buffer remain stable over time, but semen-derived enhancer of viral infection fibrils formed in phosphate buffered saline keep evolving after the initial 7 days incubation period. Given time, most of the assemblies in phosphate buffered saline will turn into elongated thin fibrils. They have similar secondary structure but different packing than thin fibrils formed initially after 7 days incubation.
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Affiliation(s)
- Xin Qiao
- Department of Physics, University of Central Florida, Orlando, Florida
| | - Jaekyun Jeon
- Department of Physics, University of Central Florida, Orlando, Florida
| | - Amy L Cole
- Department of Molecular Biology and Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida
| | - Jason O Matos
- Department of Physics, University of Central Florida, Orlando, Florida
| | - Stephany Bautista
- Department of Physics, University of Central Florida, Orlando, Florida
| | - Justin Castillo
- Department of Physics, University of Central Florida, Orlando, Florida
| | - Ivan Hung
- National High Magnetic Field Laboratory, Tallahassee, Florida
| | - Zhehong Gan
- National High Magnetic Field Laboratory, Tallahassee, Florida
| | - Suren A Tatulian
- Department of Physics, University of Central Florida, Orlando, Florida
| | - Alexander M Cole
- Department of Molecular Biology and Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida
| | - Bo Chen
- Department of Physics, University of Central Florida, Orlando, Florida.
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11
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Van Dis ES, Moore TC, Lavender KJ, Messer RJ, Keppler OT, Verheyen J, Dittmer U, Hasenkrug KJ. No SEVI-mediated enhancement of rectal HIV-1 transmission of HIV-1 in two humanized mouse cohorts. Virology 2015; 488:88-95. [PMID: 26609939 DOI: 10.1016/j.virol.2015.11.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 10/14/2015] [Accepted: 11/06/2015] [Indexed: 11/28/2022]
Abstract
Amyloid fibrils from semen-derived peptide (SEVI) enhance HIV-1 infectivity in vitro but the ability of SEVI to mediate enhancement of HIV infection in vivo has not been tested. In this study we used immunodeficient mice reconstituted with human immune systems to test for in vivo enhancement of HIV-1 transmission. This mouse model supports mucosal transmission of HIV-1 via the intrarectal route leading to productive infection. In separate experiments with humanized mouse cohorts reconstituted with two different donor immune systems, high dose HIV-1JR-CSF that had been incubated with SEVI amyloid fibrils at physiologically relevant concentrations did not show an increased incidence of infection compared to controls. In addition, SEVI failed to enhance rectal transmission with a reduced concentration of HIV-1. Although we confirmed potent SEVI-mediated enhancement of HIV infectivity in vitro, this model showed no evidence that it plays a role in the much more complex situation of in vivo transmission.
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Affiliation(s)
- Erik S Van Dis
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, MT 59840, USA
| | - Tyler C Moore
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, MT 59840, USA
| | - Kerry J Lavender
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, MT 59840, USA
| | - Ronald J Messer
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, MT 59840, USA
| | - Oliver T Keppler
- Institute of Medical Virology, National Reference Center for Retroviruses, University of Frankfurt, Frankfurt, Germany
| | - Jens Verheyen
- Institute for Virology, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany
| | - Ulf Dittmer
- Institute for Virology, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany
| | - Kim J Hasenkrug
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, MT 59840, USA.
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12
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Madison MN, Roller RJ, Okeoma CM. Human semen contains exosomes with potent anti-HIV-1 activity. Retrovirology 2014; 11:102. [PMID: 25407601 PMCID: PMC4245725 DOI: 10.1186/s12977-014-0102-z] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 10/31/2014] [Indexed: 11/16/2022] Open
Abstract
Background Exosomes are membranous nanovesicles secreted into the extracellular milieu by diverse cell types. Exosomes facilitate intercellular communication, modulate cellular pheno/genotype, and regulate microbial pathogenesis. Although human semen contains exosomes, their role in regulating infection with viruses that are sexually transmitted remains unknown. In this study, we used semen exosomes purified from healthy human donors to evaluate the role of exosomes on the infectivity of different strains of HIV-1 in a variety of cell lines. Results We show that human semen contains a heterologous population of exosomes, enriched in mRNA encoding tetraspanin exosomal markers and various antiviral factors. Semen exosomes are internalized by recipient cells and upon internalization, inhibit replication of a broad array of HIV-1 strains. Remarkably, the anti-HIV-1 activity of semen exosomes is specific to retroviruses because semen exosomes blocked replication of the murine AIDS (mAIDS) virus complex (LP-BM5). However, exosomes from blood had no effect on HIV-1 or LP-BM5 replication. Additionally, semen and blood exosomes had no effect on replication of herpes simplex virus; types 1 and 2 (HSV1 and HSV2). Mechanistic studies indicate that semen exosomes exert a post-entry block on HIV-1 replication by orchestrating deleterious effects on particle-associated reverse transcriptase activity and infectivity. Conclusions These illuminating findings i) improve our knowledge of the cargo of semen exosomes, ii) reveal that semen exosomes possess anti-retroviral activity, and iii) suggest that semen exosome-mediated inhibition of HIV-1 replication may provide novel opportunities for the development of new therapeutics for HIV-1.
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Affiliation(s)
- Marisa N Madison
- Department of Microbiology, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, IA 52242-1109, USA.
| | - Richard J Roller
- Department of Microbiology, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, IA 52242-1109, USA.
| | - Chioma M Okeoma
- Department of Microbiology, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, IA 52242-1109, USA. .,Interdisciplinary Program in Molecular and Cellular Biology, University of Iowa, Iowa City, IA 52242, USA.
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13
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Wood MP, Cole AL, Eade CR, Chen LM, Chai KX, Cole AM. The HIV-1 gp41 ectodomain is cleaved by matriptase to produce a chemotactic peptide that acts through FPR2. Immunology 2014; 142:474-83. [PMID: 24617769 PMCID: PMC4080963 DOI: 10.1111/imm.12278] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 03/05/2014] [Accepted: 03/06/2014] [Indexed: 12/21/2022] Open
Abstract
Several aspects of HIV-1 virulence and pathogenesis are mediated by the envelope protein gp41. Additionally, peptides derived from the gp41 ectodomain have been shown to induce chemotaxis in monocytes and neutrophils. Whereas this chemotactic activity has been reported, it is not known how these peptides could be produced under biological conditions. The heptad repeat 1 (HR1) region of gp41 is exposed to the extracellular environment and could therefore be susceptible to proteolytic processing into smaller peptides. Matriptase is a serine protease expressed at the surface of most epithelia, including the prostate and mucosal surfaces. Here, we present evidence that matriptase efficiently cleaves the HR1 portion of gp41 into a 22-residue chemotactic peptide MAT-1, the sequence of which is highly conserved across HIV-1 clades. We found that MAT-1 induced migration of primary neutrophils and monocytes, the latter of which act as a cellular reservoir of HIV during early stage infection. We then used formyl peptide receptor 1 (FPR1) and FPR2 inhibitors, along with HEK 293 cells, to demonstrate that MAT-1 can induce chemotaxis specifically using FPR2, a receptor found on the surface of monocytes, macrophages and neutrophils. These findings are the first to identify a proteolytic cleavage product of gp41 with chemotactic activity and highlight a potential role for matriptase in HIV-1 transmission and infection at epithelial surfaces and within tissue reservoirs of HIV-1.
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Affiliation(s)
- Matthew P Wood
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, FL, USA
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Elias AK, Scanlon D, Musgrave IF, Carver JA. SEVI, the semen enhancer of HIV infection along with fragments from its central region, form amyloid fibrils that are toxic to neuronal cells. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:1591-8. [PMID: 24948476 DOI: 10.1016/j.bbapap.2014.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 06/04/2014] [Accepted: 06/09/2014] [Indexed: 12/17/2022]
Abstract
Semen-derived enhancer of viral infection (SEVI) is the term given to the amyloid fibrils formed by a 39-amino acid fragment (PAP248-286) of prostatic acidic phosphatase (PAP) found in human semen. SEVI enhances human immunodeficiency virus (HIV) infectivity by four to five orders of magnitude (Münch et al., 2007). Here, we show by various biophysical techniques including Thioflavin T fluorescence, circular dichroism spectroscopy and transmission electron microscopy that fragments encompassing the central region of SEVI, i.e. PAP248-271 and PAP257-267, form fibrils of similar morphology to SEVI. Our results show that the central region, residues PAP267-271, is crucially important in promoting SEVI fibril formation. Furthermore, SEVI and fibrillar forms of these peptide fragments are toxic to neuronal pheochromocytoma 12 cells but not to epithelial colon carcinoma cells. These findings imply that although SEVI assists in the attachment of HIV-1 to immune cells, it may not facilitate HIV entry by damaging the epithelial cell layer that presents a barrier to the HIV.
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Affiliation(s)
- Abigail K Elias
- School of Chemistry and Physics, The University of Adelaide, South Australia 5005, Australia
| | - Denis Scanlon
- School of Chemistry and Physics, The University of Adelaide, South Australia 5005, Australia
| | - Ian F Musgrave
- Discipline of Pharmacology, School of Medical Sciences, The University of Adelaide, South Australia 5005, Australia.
| | - John A Carver
- Research School of Chemistry, The Australian National University, Australian Capital Territory 0200, Australia.
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15
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Mycoplasma genitalium promotes epithelial crossing and peripheral blood mononuclear cell infection by HIV-1. Int J Infect Dis 2014; 23:31-8. [PMID: 24661929 DOI: 10.1016/j.ijid.2013.11.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 10/18/2013] [Accepted: 11/30/2013] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Mycoplasma genitalium co-infection in HIV-infected individuals has been reported to increase the shedding of HIV in the urogenital region of females. To better understand this relationship, we investigated the influence of M. genitalium on the transmission and replication of HIV using an in vitro model. METHODS The Transwell co-culture system was employed to assess the crossing of an endocervical cell barrier by HIV-1. Immunocytochemistry and confocal microscopy were used to assess the distribution of the nectin-1 molecule on M. genitalium-infected epithelial cells of the End1/E6E7 endocervical cell line, grown as monolayers in the insert wells. Peripheral blood mononuclear cells (PBMC) were cultured in the bottom wells to assess the effects of M. genitalium, passing through the semipermeable culturing membrane, on subsequent HIV infection of susceptible target cells. RESULTS Infection of the endocervical cells with the adhesion-positive M. genitalium G37 strain (wild-type) significantly elevated the passage of HIV across the epithelial cell barrier relative to HIV transfer across endocervical cells infected with the adhesion-negative M. genitalium JB1 strain. Immunostaining of the M. genitalium-G37-infected epithelial cells disclosed capping and internalization of the junctional regulatory protein nectin-1, in association with reduced transepithelial resistance (TER) in the cell monolayer. When PBMC were cultured beneath insert wells containing M. genitalium-G37-infected epithelial cell monolayers, we observed significantly enhanced infectivity and replication of HIV added afterward to the cultures. CONCLUSIONS M. genitalium influences events on both sides of a cultured mucosal epithelial monolayer: (1) by infecting the epithelial cells and reducing the integrity of the barrier itself, and (2) by activating HIV target cells below it, thereby promoting HIV infection and progeny virus production.
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16
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Tan S, Lu L, Li L, Liu J, Oksov Y, Lu H, Jiang S, Liu S. Polyanionic candidate microbicides accelerate the formation of semen-derived amyloid fibrils to enhance HIV-1 infection. PLoS One 2013; 8:e59777. [PMID: 23544097 PMCID: PMC3609764 DOI: 10.1371/journal.pone.0059777] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 02/18/2013] [Indexed: 12/21/2022] Open
Abstract
Polyanionic candidate microbicides, including cellulose sulfate, carrageenan, PRO 2000, were proven ineffective in preventing HIV-1 transmission and even cellulose sulfate showed increased risk of HIV acquisition in the Phase III efficacy trials. Semen plays critical roles in HIV-1 sexual transmission. Specifically, amyloid fibrils formed by fragments of prostatic acidic phosphatase (PAP) in semen termed semen-derived enhancer of virus infection (SEVI) could drastically enhance HIV-1 infection. Here we investigated the interaction between polyanions and PAP248-286, a prototype peptide of SEVI, to understand the possible cause of polyanionic candidate microbicides to fail in clinical trials. We found anionic polymers could efficiently promote SEVI fibril formation, most likely mediated by the natural electrostatic interaction between polyanions and PAP248-286, as revealed by acid native PAGE and Western blot. The overall anti-HIV-1 activity of polyanions in the presence or absence of PAP248-286 or semen was evaluated. In the viral infection assay, the supernatants of polyanions/PAP248-286 or polyanions/semen mixtures containing the free, unbound polyanionic molecules showed a general reduction in antiviral efficacy, while the pellets containing amyloid fibrils formed by the polyanion-bound PAP248-286 showed aggravated enhancement of viral infection. Collectively, from the point of drug-host protein interaction, our study revealed that polyanions facilitate SEVI fibril formation to promote HIV-1 infection, thus highlighting a molecular mechanism underlying the failure of polyanions in clinical trials and the importance of drug-semen interaction in evaluating the anti-HIV-1 efficacy of candidate microbicides.
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Affiliation(s)
- Suiyi Tan
- School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
- Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America
| | - Lu Lu
- Key Laboratory of Medical Molecular Virology of Ministries of Education & Health, Shanghai Medical College and Institute of Medical Microbiology, Fudan University, Shanghai, China
- Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America
| | - Lin Li
- School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Jixiang Liu
- Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America
| | - Yelena Oksov
- Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America
| | - Hong Lu
- Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America
| | - Shibo Jiang
- School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
- Key Laboratory of Medical Molecular Virology of Ministries of Education & Health, Shanghai Medical College and Institute of Medical Microbiology, Fudan University, Shanghai, China
- Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America
- * E-mail: (SJ); (SL)
| | - Shuwen Liu
- School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
- * E-mail: (SJ); (SL)
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17
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Hartman K, Brender JR, Monde K, Ono A, Evans M, Popovych N, Chapman MR, Ramamoorthy A. Bacterial curli protein promotes the conversion of PAP248-286 into the amyloid SEVI: cross-seeding of dissimilar amyloid sequences. PeerJ 2013; 1:e5. [PMID: 23638387 PMCID: PMC3629062 DOI: 10.7717/peerj.5] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 12/05/2012] [Indexed: 01/02/2023] Open
Abstract
Fragments of prostatic acid phosphatase (PAP248-286) in human semen dramatically increase HIV infection efficiency by increasing virus adhesion to target cells. PAP248-286 only enhances HIV infection in the form of amyloid aggregates termed SEVI (Semen Enhancer of Viral Infection), however monomeric PAP248-286 aggregates very slowly in isolation. It has therefore been suggested that SEVI fiber formation in vivo may be promoted by exogenous factors. We show here that a bacterially-produced extracellular amyloid (curli or Csg) acts as a catalytic agent for SEVI formation from PAP248-286 at low concentrations in vitro, producing fibers that retain the ability to enhance HIV (Human Immunodeficiency Virus) infection. Kinetic analysis of the cross-seeding effect shows an unusual pattern. Cross-seeding PAP248-286 with curli only moderately affects the nucleation rate while significantly enhancing the growth of fibers from existing nuclei. This pattern is in contrast to most previous observations of cross-seeding, which show cross-seeding partially bypasses the nucleation step but has little effect on fiber elongation. Seeding other amyloidogenic proteins (IAPP (islet amyloid polypeptide) and Aβ1-40) with curli showed varied results. Curli cross-seeding decreased the lag-time of IAPP amyloid formation but strongly inhibited IAPP elongation. Curli cross-seeding exerted a complicated concentration dependent effect on Aβ1-40 fibrillogenesis kinetics. Combined, these results suggest that the interaction of amyloidogenic proteins with preformed fibers of a different type can take a variety of forms and is not limited to epitaxial nucleation between proteins of similar sequence. The ability of curli fibers to interact with proteins of dissimilar sequences suggests cross-seeding may be a more general phenomenon than previously supposed.
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Affiliation(s)
- Kevin Hartman
- Department of Chemistry, University of Michigan, USA
- Department of Biophysics, University of Michigan, USA
| | - Jeffrey R. Brender
- Department of Chemistry, University of Michigan, USA
- Department of Biophysics, University of Michigan, USA
| | - Kazuaki Monde
- Department of Microbiology and Immunology, University of Michigan Medical School, USA
| | - Akira Ono
- Department of Microbiology and Immunology, University of Michigan Medical School, USA
| | - Margery L. Evans
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, USA
| | - Nataliya Popovych
- Department of Chemistry, University of Michigan, USA
- Department of Biophysics, University of Michigan, USA
| | - Matthew R. Chapman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, USA
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry, University of Michigan, USA
- Department of Biophysics, University of Michigan, USA
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Inhibition of semen-derived enhancer of virus infection (SEVI) fibrillogenesis by zinc and copper. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 41:695-704. [PMID: 22907203 DOI: 10.1007/s00249-012-0846-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 07/15/2012] [Accepted: 07/27/2012] [Indexed: 01/27/2023]
Abstract
Semen-derived enhancer of virus infection (SEVI), a naturally occurring peptide fragment of prostatic acid phosphatase, enhances HIV infectivity by forming cationic amyloid fibrils that aid the fusion of negatively charged virion and target cell membranes. Cu(II) and Zn(II) inhibit fibrillization of SEVI in a kinetic assay using the fibril-specific dye ThT. TEM suggests that the metals do not affect fibril morphology. NMR shows that the metals bind to histidines 3 and 23 in the SEVI sequence. ITC experiments indicate that SEVI forms oligomeric complexes with the metals. Dissociation constants are micromolar for Cu(II) and millimolar for Zn(II). Because the Cu(II) and Zn(II) concentrations that inhibit fibrillization are comparable with those found in seminal fluid the metals may modulate SEVI fibrillization under physiological conditions.
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Castellano LM, Shorter J. The Surprising Role of Amyloid Fibrils in HIV Infection. BIOLOGY 2012; 1:58-80. [PMID: 24832047 PMCID: PMC4011035 DOI: 10.3390/biology1010058] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Revised: 05/19/2012] [Accepted: 05/23/2012] [Indexed: 01/18/2023]
Abstract
Despite its discovery over 30 years ago, human immunodeficiency virus (HIV) continues to threaten public health worldwide. Semen is the principal vehicle for the transmission of this retrovirus and several endogenous peptides in semen, including fragments of prostatic acid phosphatase (PAP248-286 and PAP85-120) and semenogelins (SEM1 and SEM2), assemble into amyloid fibrils that promote HIV infection. For example, PAP248-286 fibrils, termed SEVI (Semen derived Enhancer of Viral Infection), potentiate HIV infection by up to 105-fold. Fibrils enhance infectivity by facilitating virion attachment and fusion to target cells, whereas soluble peptides have no effect. Importantly, the stimulatory effect is greatest at low viral titers, which mimics mucosal transmission of HIV, where relatively few virions traverse the mucosal barrier. Devising a method to rapidly reverse fibril formation (rather than simply inhibit it) would provide an innovative and urgently needed preventative strategy for reducing HIV infection via the sexual route. Targeting a host-encoded protein conformer represents a departure from traditional microbicidal approaches that target the viral machinery, and could synergize with direct antiviral approaches. Here, we review the identification of these amyloidogenic peptides, their mechanism of action, and various strategies for inhibiting their HIV-enhancing effects.
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Affiliation(s)
- Laura M Castellano
- Pharmacology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - James Shorter
- Pharmacology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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Olsen JS, DiMaio JTM, Doran TM, Brown C, Nilsson BL, Dewhurst S. Seminal plasma accelerates semen-derived enhancer of viral infection (SEVI) fibril formation by the prostatic acid phosphatase (PAP248-286) peptide. J Biol Chem 2012; 287:11842-9. [PMID: 22354963 PMCID: PMC3320932 DOI: 10.1074/jbc.m111.314336] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Amyloid fibrils contained in semen, known as SEVI, or semen-derived enhancer of viral infection, have been shown to increase the infectivity of HIV dramatically. However, previous work with these fibrils has suggested that extensive time and nonphysiologic levels of agitation are necessary to induce amyloid formation from the precursor peptide (a proteolytic cleavage product of prostatic acid phosphatase, PAP248–286). Here, we show that fibril formation by PAP248–286 is accelerated dramatically in the presence of seminal plasma (SP) and that agitation is not required for fibrillization in this setting. Analysis of the effects of specific SP components on fibril formation by PAP248–286 revealed that this effect is primarily due to the anionic buffer components of SP (notably inorganic phosphate and sodium bicarbonate). Divalent cations present in SP had little effect on the kinetics of fibril formation, but physiologic levels of Zn2+ strongly protected SEVI fibrils from degradation by seminal proteases. Taken together, these data suggest that in the in vivo environment, PAP248–286 is likely to form fibrils efficiently, thus providing an explanation for the presence of SEVI in human semen.
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Affiliation(s)
- Joanna S Olsen
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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Assessment of the range of the HIV-1 infectivity enhancing effect of individual human semen specimen and the range of inhibition by EGCG. AIDS Res Ther 2012; 9:2. [PMID: 22260499 PMCID: PMC3308922 DOI: 10.1186/1742-6405-9-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 01/19/2012] [Indexed: 11/11/2022] Open
Abstract
Recently, it has been shown that human ejaculate enhances human immunodeficiency virus 1 (HIV-1) infectivity. Enhancement of infectivity is conceived to be mediated by amyloid filaments from peptides that are proteolytically released from prostatic acid phosphatase (PAP), termed Semen-derived Enhancer of Virus Infection (SEVI). The aim of this study was to test the range of HIV-1 infectivity enhancing properties of a large number of individual semen samples (n = 47) in a TZM-bl reporter cell HIV infection system. We find that semen overall increased infectivity to 156% of the control experiment without semen, albeit with great inter- and intraindividual variability (range -53%-363%). Using transmission electron microscopy, we provide evidence for SEVI fibrils in fresh human semen for the first time. Moreover, we confirm that the infectivity enhancing property can be inhibited by the major green tea ingredient epigallocatechin-3-gallate (EGCG) at non-toxic concentrations. The median inhibition of infection by treatment with 0.4 mM EGCG was 70.6% (p < 0.0001) in our cohort. Yet, there were substantial variations of inhibition and in a minority of samples, infectivity enhancement was not inhibited by EGCG treatment at all. Thus, topical application of EGCG may be a feasible additional measure to prevent the sexual transmission of HIV. However, the reasons for the variability in the efficacy of the abrogation of semen-mediated enhancement of HIV-1 infectivity and EGCG efficacy have to be elucidated before therapeutic trials can be conducted.
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