title: Impact of HIV-1 Membrane Cholesterol on Cell-Independent Lytic Inactivation and Cellular Infectivity.
abstract: Peptide triazole thiols (PTTs) have been found previously to bind to HIV-1 Env spike gp120 and cause irreversible virus inactivation by shedding gp120 and lytically releasing luminal capsid protein p24. Since the virions remain visually intact, lysis appears to occur via limited membrane destabilization. To better understand the PTT-triggered membrane transformation involved, we investigated the role of envelope cholesterol on p24 release by measuring the effect of cholesterol depletion using methyl beta-cyclodextrin (MβCD). An unexpected bell-shaped response of PTT-induced lysis to [MβCD] was observed, involving lysis enhancement at low [MβCD] vs loss of function at high [MβCD]. The impact of cholesterol depletion on PTT-induced lysis was reversed by adding exogenous cholesterol and other sterols that support membrane rafts, while sterols that do not support rafts induced only limited reversal. Cholesterol depletion appears to cause a reduced energy barrier to lysis as judged by decreased temperature dependence with MβCD. Enhancement/replenishment responses to [MβCD] also were observed for HIV-1 infectivity, consistent with a similar energy barrier effect in the membrane transformation of virus cell fusion. Overall, the results argue that cholesterol in the HIV-1 envelope is important for balancing virus stability and membrane transformation, and that partial depletion, while increasing infectivity, also makes the virus more fragile. The results also reinforce the argument that the lytic inactivation and infectivity processes are mechanistically related and that membrane transformations occurring during lysis can provide an experimental window to investigate membrane and protein factors important for HIV-1 cell entry.
authors.affiliation: Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, Pennsylvania 19102, United States.|School of Biomedical Engineering, Science and Health Systems, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Ramalingam Venkat
authors.initials: RV
authors.lastname: Kalyana Sundaram
authors.affiliation: Shared Research Facilities, West Virginia University , Morgantown, West Virginia 26506, United States.
authors.forename: Huiyuan
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, Pennsylvania 19102, United States.
authors.forename: Lauren
authors.initials: L
authors.lastname: Bailey
authors.affiliation: Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, Pennsylvania 19102, United States.
authors.forename: Adel A
authors.initials: AA
authors.lastname: Rashad
authors.affiliation: Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, Pennsylvania 19102, United States.
authors.forename: Rachna
authors.initials: R
authors.lastname: Aneja
authors.affiliation: Department of Chemical and Biological Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Karl
authors.initials: K
authors.lastname: Weiss
authors.affiliation: Department of Biological Sciences, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: James
authors.initials: J
authors.lastname: Huynh
authors.affiliation: Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, Pennsylvania 19102, United States.|School of Biomedical Engineering, Science and Health Systems, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Arangaserry Rosemary
authors.initials: AR
authors.lastname: Bastian
authors.affiliation: School of Biomedical Engineering, Science and Health Systems, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Papazoglou
authors.affiliation: Department of Chemical and Biological Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Cameron
authors.initials: C
authors.lastname: Abrams
authors.affiliation: Department of Chemical and Biological Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Steven
authors.initials: S
authors.lastname: Wrenn
authors.affiliation: Department of Biochemistry and Molecular Biology, Drexel University College of Medicine , Philadelphia, Pennsylvania 19102, United States.
authors.forename: Irwin
authors.initials: I
authors.lastname: Chaiken
mesh_terms: D045744:Cell Line, Tumor; D002784:Cholesterol / Q000378:metabolism*; D016655:HIV Core Protein p24 / Q000378:metabolism; D015699:HIV Envelope Protein gp120 / Q000378:metabolism; D015497:HIV-1 / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology*; D006801:Humans; D008560:Membrane Fluidity; D008563:Membrane Lipids / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000494:pharmacology; D013844:Thiazoles / Q000737:chemistry / Q000494:pharmacology; D014230:Triazoles / Q000737:chemistry / Q000494:pharmacology; D047392:beta-Cyclodextrins / Q000494:pharmacology
chemical_list: D016655:HIV Core Protein p24; D015699:HIV Envelope Protein gp120; C000608271:KR-13 peptide; D008563:Membrane Lipids; D010455:Peptides; D013438:Sulfhydryl Compounds; D013844:Thiazoles; D014230:Triazoles; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; C514799:p24 protein, Human Immunodeficiency Virus Type 1; D002784:Cholesterol