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Christian Wächter, Lee E Eiden, Nedye Naumann, Candan Depboylu, Eberhard Weihe
BACKGROUND: The majority of investigations on HIV-associated neurocognitive disorders (HAND) neglect the cerebellum in spite of emerging evidence for its role in higher cognitive functions and dysfunctions in common neurodegenerative diseases. METHODS: We systematically investigated the molecular and cellular responses of the cerebellum as contributors to lentiviral infection-induced neurodegeneration, in the simian immunodeficiency virus (SIV)-infected rhesus macaque model for HIV infection and HAND...
October 14, 2016: Journal of Neuroinflammation
Maarten Danial, Angela Stauffer, Frederik R Wurm, Michael J Root, Harm-Anton Klok
A popular strategy to overcome the limited plasma half-life of peptide heptad repeat 2 (HR2) fusion inhibitors against HIV-1 is through conjugation with biocompatible polymers such as poly(ethylene glycol) (PEG). However, despite improved resistance to proteolysis and reduced renal elimination, covalent attachment of polymers often causes a loss in therapeutic potency. In this study, we investigated the molecular origins of the loss in potency upon conjugation of linear, mid-functional and hyperbranched PEG-like polymers to peptides that inhibit HIV-1 - host cell membrane fusion...
October 13, 2016: Bioconjugate Chemistry
Bibek Parajuli, Kriti Acharya, Reina Yu, Brendon Ngo, Adel A Rashad, Cameron F Abrams, Irwin M Chaiken
We recently reported discovery of a recombinant chimera, denoted DAVEI (Dual Acting Virucidal Entry Inhibitor), which is able to selectively cause specific and potent lytic inactivation of both pseudotyped and fully infectious HIV-1 virions. The chimera is composed of the lectin cyanovirin-N (CVN) fused to the 20-residue membrane-proximal external region (MPER) of HIV-1 gp41. Since the Env gp120-binding CVN domain on its own is not lytic, we sought here to determine how the MPER(DAVEI) domain is able to endow the chimera with virolytic activity...
October 12, 2016: Biochemistry
Saghi Sepehri, Lotfollah Saghaie, Afshin Fassihi
The fusion of viral and host cell membranes is mediated using gp41 subunit of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein. As the HIV-1 enters the host cells, the two helical regions (HR1 and HR2) in the ectodomain of gp41 form a six-helix bundle, which carries the target and viral cell membranes to close proximity. Steps of this process serve as attractive targets for developing HIV-1 fusion inhibitors. Identification of some novel HIV fusion inhibitors with the goal of blocking the formation of the six-helix bundle was accomplished by computer-aided drug design techniques...
October 12, 2016: Molecular Informatics
Dina Tsukrov, Alicia McFarren, Alfred Morgenstern, Frank Bruchertseifer, Eugene Dolce, Miroslaw K Gorny, Susan Zolla-Pazner, Joan W Berman, Ellie Schoenbaum, Barry S Zingman, Arturo Casadevall, Ekaterina Dadachova
Eliminating virally infected cells is an essential component of any HIV eradication strategy. Radioimmunotherapy (RIT), a clinically established method for killing cells using radiolabeled antibodies, was recently applied to target HIV-1 gp41 antigen expressed on the surface of infected cells. Since gp41 expression by infected cells is likely downregulated in patients on antiretroviral therapy (ART), we evaluated the ability of RIT to kill ART-treated infected cells using both in vitro models and lymphocytes isolated from HIV-infected subjects...
2016: Frontiers in Medicine
Mohammed Asmal, Sophie Lane, Meijuan Tian, Gabrielle Nickel, Colin Venner, Brennan Dirk, Jimmy Dikeakos, Corinne Luedemann, Linh Mach, Harikrishnan Balachandran, Adam Buzby, Srinivas Rao, Norman Letvin, Yong Gao, Eric J Arts
For studies on vaccines and therapies for HIV disease, SIV-HIV chimeric viruses harboring the HIV-1 env gene (SHIVenv) remain the best virus in non-human primate models. However, there are still very few SHIVenv viruses that can cause AIDS in non-CD8-depleted animals. In the present study, a recently created CCR5-using SHIVenv_B3 virus with env gene derived from acute/early HIV-1 infections (AHI) successfully established pathogenic infection in macaques. Through a series of investigations on the evolution, mutational profile, and phenotype of the virus and the resultant humoral immune response in infected rhesus macaques, we found that the E32K mutation in the Env C1 domain was associated with macaque pathogenesis, and that the electrostatic interactions in Env may favor E32K at the gp120 N terminus and "lock" the binding to heptad repeat 1 of gp41 in the trimer and produce a SHIVenv with increased fitness and pathogenesis during macaque infections...
October 6, 2016: Virology
Xiaowei Zhang, Fei Zhang, Xiaohe Ma, Xing Zhao, Wei Li, Zhiping Zhang, Jibin Zhang, Xian-En Zhang, Zongqiang Cui
Human immunodeficiency virus-1 (HIV-1) encodes 15 viral proteins. Protein-protein interactions play a large role in the function of these proteins. In this study, we attempted to identify novel interactions between the HIV-1 proteins to better understand the role played by viral protein-protein interactions in the life cycle of HIV-1. Genes encoding the 15 viral proteins from the HIV-1 strain AD8 were inserted into the plasmids of a yeast two-hybrid system. By screening 120 pairs of proteins, interactions between seven pairs were found...
September 26, 2016: Virologica Sinica
Muntasir Alam, Takeo Kuwata, Kazuya Shimura, Masaru Yokoyama, Kristel Paola Ramirez Valdez, Kazuki Tanaka, Yasuhiro Maruta, Shinya Oishi, Nobutaka Fujii, Hironori Sato, Masao Matsuoka, Shuzo Matsushita
BACKGROUND: HIV-1 typically develops resistance to any single antiretroviral agent. Combined anti-retroviral therapy to reduce drug-resistance development is necessary to control HIV-1 infection. Here, to assess the utility of a combination of antibody and fusion inhibitor treatments, we investigated the potency of monoclonal antibodies at neutralizing HIV-1 variants that are resistant to fusion inhibitors. RESULTS: Mutations that confer resistance to four fusion inhibitors, enfuvirtide, C34, SC34, and SC34EK, were introduced into the envelope of HIV-1JR-FL, a CCR5-tropic tier 2 strain...
September 27, 2016: Retrovirology
Yun Zhu, Shan Su, Lili Qin, Qian Wang, Lei Shi, Zhenxuan Ma, Jianchao Tang, Shibo Jiang, Lu Lu, Sheng Ye, Rongguang Zhang
Peptides derived from the C-terminal heptad repeat (CHR) of HIV gp41 have been developed as effective fusion inhibitors against HIV-1, but facing the challenges of enhancing potency and stability. Here, we report a rationally designed novel HIV-1 fusion inhibitor derived from CHR-derived peptide (Trp628~Gln653, named CP), but with an innovative Ile-Asp-Leu tail (IDL) that dramatically increased the inhibitory activity by up to 100 folds. We also determined the crystal structures of artificial fusion peptides N36- and N43-L6-CP-IDL...
September 26, 2016: Scientific Reports
Xiaozhou Luo, Tsung-Shing Andrew Wang, Yong Zhang, Feng Wang, Peter G Schultz
The N-peptide of HIV gp41 forms a trimeric coiled-coil intermediate during host cell-viral fusion. Stable mimics of this coiled coil could potentially serve as HIV vaccine candidates or inhibitors of viral entry. Therefore, a variety of approaches have been investigated to maintain the N-peptide in its trimeric helical conformation. Here, we utilize a genetic method to incorporate the metal chelating noncanonical amino acid (2,2'-bipyridin-5-yl)alanine (BpyAla) into IZN17, an established trimeric coiled-coil gp41 model...
September 22, 2016: Cell Chemical Biology
Anne-Marie C Andersson, Emeline Ragonnaud, Kelly E Seaton, Sheetal Sawant, Antonella Folgori, Stefano Colloca, Celia Labranche, David C Montefiori, Georgia D Tomaras, Peter J Holst
The low number of envelope (Env) spikes presented on native HIV-1 particles is a major impediment for HIV-1 prophylactic vaccine development. We designed virus-like particle encoding adenoviral vectors utilizing SIVmac239 Gag as an anchor for full length and truncated HIV-1 M consensus Env. Truncated Env overexpressed VRC01 and 17b binding antigen on the surface of transduced cells while the full length Env vaccine presented more and similar amounts of antigen binding to the trimer conformation sensitive antibodies PGT151 and PGT145, respectively...
October 17, 2016: Vaccine
Xifeng Jiang, Qiyan Jia, Lu Lu, Fei Yu, Jishen Zheng, Weiguo Shi, Lifeng Cai, Shibo Jiang, Keliang Liu
HIV-1 fusion with the target cell is initiated by the insertion of the gp41 fusion peptide (FP) into the target cell membrane and the interaction between the gp41 N- and C-terminal heptad repeats (NHR and CHR), followed by the formation of the six-helix bundle (6-HB) fusion core. Therefore, both FP and NHR are important targets for HIV-1 fusion inhibitors. Here, we designed and synthesized a dual-target peptidic HIV-1 fusion inhibitor, 4HR-LBD-VIRIP, in which 4HR-LBD is able to bind to the gp41 NHR domain, while VIRIP is able to interact with gp41 FP...
September 8, 2016: Amino Acids
Todd Bradley, Ashley Trama, Nancy Tumba, Elin Gray, Xiaozhi Lu, Navid Madani, Fatemeh Jahanbakhsh, Amanda Eaton, Shi-Mao Xia, Robert Parks, Krissey E Lloyd, Laura L Sutherland, Richard M Scearce, Cindy M Bowman, Susan Barnett, Salim S Abdool-Karim, Scott D Boyd, Bruno Melillo, Amos B Smith, Joseph Sodroski, Thomas B Kepler, S Munir Alam, Feng Gao, Mattia Bonsignori, Hua-Xin Liao, M Anthony Moody, David Montefiori, Sampa Santra, Lynn Morris, Barton F Haynes
Most HIV-1 vaccines elicit neutralizing antibodies that are active against highly sensitive (tier-1) viruses or rare cases of vaccine-matched neutralization-resistant (tier-2) viruses, but no vaccine has induced antibodies that can broadly neutralize heterologous tier-2 viruses. In this study, we isolated antibodies from an HIV-1-infected individual that targeted the gp41 membrane-proximal external region (MPER) that may have selected single-residue changes in viral variants in the MPER that resulted in neutralization sensitivity to antibodies targeting distal epitopes on the HIV-1 Env...
August 31, 2016: EBioMedicine
Matthew Zirui Tay, Pinghuang Liu, LaTonya D Williams, Michael D McRaven, Sheetal Sawant, Thaddeus C Gurley, Thomas T Xu, S Moses Dennison, Hua-Xin Liao, Agnès-Laurence Chenine, S Munir Alam, M Anthony Moody, Thomas J Hope, Barton F Haynes, Georgia D Tomaras
Emerging data support a role for antibody Fc-mediated antiviral activity in vaccine efficacy and in the control of HIV-1 replication by broadly neutralizing antibodies. Antibody-mediated virus internalization is an Fc-mediated function that may act at the portal of entry whereby effector cells may be triggered by pre-existing antibodies to prevent HIV-1 acquisition. Understanding the capacity of HIV-1 antibodies in mediating internalization of HIV-1 virions by primary monocytes is critical to understanding their full antiviral potency...
August 2016: PLoS Pathogens
María José Gómara, Ignacio Pérez-Pomeda, José María Gatell, Victor Sánchez-Merino, Eloisa Yuste, Isabel Haro
The work reports the design and synthesis of a chimeric peptide that is comprised of the peptide sequences of two entry inhibitors which target different sites of HIV-1 gp41. The chimeric peptide offers the advantage of targeting two gp41 regions simultaneously: the fusion peptide and the loop both of which are membrane active and participate in the membrane fusion process. We therefore use lipid raft-like liposomes as a tool to specifically direct the chimeric inhibitor peptide to the membrane domains where the HIV-1 envelope protein is located...
August 23, 2016: Nanomedicine: Nanotechnology, Biology, and Medicine
Chao Wang, Xue Li, Fei Yu, Lu Lu, Xifeng Jiang, Xiaoyu Xu, Huixin Wang, Wenqing Lai, Tianhong Zhang, Zhenqing Zhang, Ling Ye, Shibo Jiang, Keliang Liu
Peptides derived from the N-terminal heptad repeat (NHR) of HIV-1 gp41 can be potent inhibitors against viral entry when presented in a nonaggregating trimeric coiled-coil conformation via the introduction of exogenous trimerization motifs and intermolecular disulfide bonds. We recently discovered that crosslinking isopeptide bridges within the de novo helical trimers added exceptional resistance to unfolding. Herein, we attempted to optimize (CCIZN17)3, a representative disulfide bond-stabilized chimeric NHR-trimer, by incorporating site-specific interhelical isopeptide bonds as the redox-sensitive disulfide surrogate...
2016: Scientific Reports
Fadia Manssour-Triedo, Sara Crespillo, Bertrand Morel, Salvador Casares, Pedro L Mateo, Frank Notka, Marie G Roger, Nicolas Mouz, Raphaelle El-Habib, Francisco Conejero-Lara
The HIV gp41 ectodomain (e-gp41) is an attractive target for the development of vaccines and drugs against HIV because of its crucial role in viral fusion to the host cell. However, because of the high insolubility of e-gp41, most biophysical and structural analyses have relied on the production of truncated versions removing the loop region of gp41 or the utilization of nonphysiological solubilizing conditions. The loop region of gp41 is also known as principal immunodominant domain (PID) because of its high immunogenicity, and it is essential for gp41-mediated HIV fusion...
August 23, 2016: Biophysical Journal
Deeksha Pandey, Avijit Podder, Mansi Pandit, Narayanan Latha
The major causative agent for Acquired Immune Deficiency Syndrome (AIDS) is Human Immunodeficiency Virus-1 (HIV-1). HIV-1 is a predominant subtype of Human Immunodeficiency Virus which counts on human cellular mechanism virtually in every aspect of its life cycle. Binding of viral envelope glycoprotein-gp120 with human cell surface CD4 receptor triggers the early infection stage of HIV-1. This study focuses on the interaction interface between these two proteins that play a crucial role for viral infectivity...
August 21, 2016: Journal of Biomolecular Structure & Dynamics
Shilei Ding, Halima Medjahed, Jérémie Prévost, Mathieu Coutu, Shi-Hua Xiang, Andrés Finzi
: Binding of HIV-1 and SIV gp120 exterior envelope glycoprotein to CD4 triggers conformational changes in gp120 that promote its interaction with one of the chemokine receptors, usually CCR5, ultimately leading to gp41-mediated virus-cell membrane fusion and entry. We previously described that topological Layers (Layer 1, Layer 2 and Layer 3) in the gp120 inner domain contribute to gp120-trimer association in the unliganded state but also help secure CD4 binding. Relative to Layer 1 of HIV-1 gp120, the SIVmac239 gp120 Layer 1 plays a more prominent role in maintaining gp120-trimer association but is minimally involved in promoting CD4 binding, which could be explained by the existence of a well-conserved Tryptophan 375 (Trp 375) in HIV-2/SIVsmm...
August 17, 2016: Journal of Virology
John M Louis, James L Baber, Rodolfo Ghirlando, Annie Aniana, Ad Bax, Julien Roche
The transitioning of the ectodomain of gp41 from a pre-hairpin to a six-helix bundle conformation is a crucial aspect of virus-cell fusion. To gain insight into the intermediary steps of the fusion process we have studied the pH and dodecyl phosphocholine (DPC) micelle dependent trimer association of gp41 by systematic deletion analysis of an optimized construct termed 17-172 (residues 528 to 683 of Env) that spans the fusion peptide proximal region (FPPR) to the membrane proximal external region (MPER) of gp41, by sedimentation velocity and double electron-electron resonance (DEER) EPR spectroscopy...
2016: PloS One
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