scholarly journals Apoptosis Induced by Infection of Primary Brain Cultures with Diverse Human Immunodeficiency Virus Type 1 Isolates: Evidence for a Role of the Envelope

1999 ◽  
Vol 73 (2) ◽  
pp. 897-906 ◽  
Author(s):  
Asa Ohagen ◽  
Sajal Ghosh ◽  
Jianglin He ◽  
Karen Huang ◽  
Youzhi Chen ◽  
...  
Keyword(s):  
Replication Capacity ◽  
Immunodeficiency Virus ◽  
The Central Nervous System ◽  
Late Stages ◽  
The Brain ◽  
V3 Region ◽  
Hiv 1

ABSTRACT Apoptosis of neurons and astrocytes is induced by human immunodeficiency type 1 (HIV-1) infection in vitro and has been demonstrated in brain tissue from patients with AIDS. We analyzed a panel of diverse HIV-1 primary isolates for the ability to replicate and induce neuronal and astrocyte apoptosis in primary human brain cultures. Apoptosis was induced three- to eightfold by infection with the blood-derived HIV-1 isolates 89.6, SG3, and ADA. In contrast, the brain-derived HIV-1 isolates YU2, JRFL, DS-br, RC-br, and KJ-br did not induce significant levels of apoptosis. The ability of HIV-1 isolates to induce apoptosis was independent of their replication capacity. Studies of recombinant chimeras between the SG3 and YU2 viruses showed that replacement of the YU2 Env with the SG3 Env was sufficient to confer the ability to induce apoptosis to the YU2 virus. Replacement of the Env V3 regions alone largely conferred the phenotypes of the parental clones. The SG3 Env used CXCR4 and CCR3 as coreceptors for virus entry, whereas YU2 used CCR5 and CCR3. The V3 regions of SG3 and YU2 conferred the ability to use CXCR4 and CCR5, respectively. In contrast, the 3′ region of Env, particularly the C3V4 region, was required in conjunction with the V3 region for efficient use of CCR3. These results provide evidence that Env is a major determinant of neurodegenerative mechanisms associated with HIV-1 infection in vitro and raise the possibility that blood-derived viruses which emerge during the late stages of disease may affect disease progression in the central nervous system.

scholarly journals Relationship between In Vitro Human Immunodeficiency Virus Type 1 Replication Rate and Virus Load in Plasma

2003 ◽  
Vol 77 (22) ◽  
pp. 12105-12112 ◽  
Author(s):  
Thomas B. Campbell ◽  
Kristina Schneider ◽  
Terri Wrin ◽  
Christos J. Petropoulos ◽  
Elizabeth Connick
Keyword(s):  
Replication Capacity ◽  
Replication Rate ◽  
Plasma Virus ◽  
Virus Load ◽  
Immunodeficiency Virus ◽  
Plasma Virus Load ◽  
Hiv 1 ◽  
Rna Concentration

ABSTRACT Although plasma human immunodeficiency virus type 1 (HIV-1) RNA concentration is a major determinant of the rate of HIV-1 disease progression, the reasons for variability in plasma virus loads among infected individuals are not fully understood. We conducted investigations with 15 HIV-1-infected individuals who were not receiving antiretroviral therapy to evaluate the hypothesis that HIV-1 replication rate in vitro is a significant determinant of plasma virus load. Virus could not be isolated from one subject. Two subjects were excluded because they had features previously associated with distinct plasma virus loads and altered rates of disease progression; one harbored a syncytium-inducing virus and the second was heterozygous for a 32-bp deletion from the CCR5 gene. HIV-1 replication rates were determined by culturing autologous virus isolates in phytohemagglutinin-treated peripheral blood mononuclear cells (PBMC) and determining the rate of p24 antigen production during the logarithmic phase of viral replication. The contribution of HIV-1 reverse transcriptase (RT) and protease (PR) alleles to replication capacity was assessed using recombinant viruses in a single-cycle infection assay. HIV-1 replication rates ranged from 0.15 to 0.76 log10 pg/ml/day and were reproducible within the same donor PBMC (coefficient of variation ± 4%). RT-PR replication capacity ranged from 14 to 95% of that of control virus and was linearly related to replication rate (r 2 = 0.53; P = 0.007). Plasma HIV-1 RNA concentration was linearly related to replication rate (r 2 = 0.71; P < 0.001) and RT-PR replication capacity (r 2 = 0.44; P = 0.019). These data suggest that different RT-PR alleles are important determinants of HIV-1 replication rates and that HIV-1 replication rate explains much of the variability in plasma virus load in chronic HIV-1 infection.

Dementia and the Neurovirulence of HIV-1

CNS Spectrums ◽  
2000 ◽  
Vol 5 (4) ◽  
pp. 31-42 ◽  
Author(s):  
Paul Shapshak ◽  
Robert K. Fujimura ◽  
Ashok Srivastava ◽  
Karl Goodkin
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiretroviral Therapy ◽  
Human Immunodeficiency Virus Type ◽  
Neuropsychological Impairment ◽  
Motor Disorder ◽  
Immunodeficiency Virus ◽  
The Brain ◽  
Hiv 1

AbstractInfection with human immunodeficiency virus type 1 (HIV-1 ) leads rapidly to infection of the brain and subsequent neuropsychological impairment, including subclinical impairment, minor cognitive-motor disorder, and HIV-1–associated dementia (HAD). This article reviews HAD and the factors involved in its pathogenesis; the effectiveness of antiretroviral therapy; the prevalence of HIV-1 and subtypes; and the role of chemokines and cytokines as the capstones associated with neuropathology due to inflammation.

scholarly journals Cholesterol-Depleting Statin Drugs Protect Postmitotically Differentiated Human Neurons against Ethanol- and Human Immunodeficiency Virus Type 1-Induced Oxidative Stress In Vitro

2006 ◽  
Vol 81 (3) ◽  
pp. 1492-1501 ◽  
Author(s):  
Edward Acheampong ◽  
Zahida Parveen ◽  
Aschalew Mengistu ◽  
Noel Ngoubilly ◽  
Brian Wigdahl ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Human Immunodeficiency Virus Type ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
The Brain ◽  
Hiv 1

ABSTRACT The majority of human immunodeficiency virus type 1 (HIV-1)-infected individuals are either alcoholics or prone to alcoholism. Upon ingestion, alcohol is easily distributed into the various compartments of the body, particularly the brain, by crossing through the blood-brain barrier. Both HIV-1 and alcohol induce oxidative stress, which is considered a precursor for cytotoxic responses. Several reports have suggested that statins exert antioxidant as well as anti-inflammatory pleiotropic effects, besides their inherent cholesterol-depleting potentials. In our studies, postmitotically differentiated neurons were cocultured with HIV-1-infected monocytes, T cells, or their cellular supernatants in the presence of physiological concentrations of alcohol for 72 h. Parallel cultures were pretreated with statins (atorvastatin and simvastatin) with the appropriate controls, i.e., postmitotically differentiated neurons cocultured with uninfected cells and similar cultures treated with alcohol. The oxidative stress responses in the presence/absence of alcohol in these cultures were determined by the production of the well-characterized oxidative stress markers, 8-isoprostane-F2-α, total nitrates as an indicator for various isoforms of nitric oxide synthase activity, and heat shock protein 70 (Hsp70). An in vitro culture of postmitotically differentiated neurons with HIV-1-infected monocytes or T cells as well as supernatants from these cells enhanced the release of 8-isoprostane-F2-α in the conditioned medium six- to sevenfold (monocytes) and four- to fivefold (T cells). It was also observed that coculturing of HIV-1-infected primary monocytes over a time period of 72 h significantly elevated the release of Hsp70 compared with that of uninfected controls. Cellular supernatants of HIV-1-infected monocytes or T cells slightly increased Hsp70 levels compared to neurons cultured with uninfected monocytes or T-cell supernatants (controls). Ethanol (EtOH) presence further elevated Hsp70 in both infected and uninfected cultures. The amount of total nitrates was significantly elevated in the coculture system when both infected cells and EtOH were present. Surprisingly, pretreatment of postmitotic neurons with clinically available inhibitors of HMG-coenzyme A reductase (statins) inhibited HIV-1-induced release of stress/toxicity-associated parameters, i.e., Hsp70, isoprostanes, and total nitrates from HIV-1-infected cells. The results of this study provide new insights into HIV-1 neuropathogenesis aimed at the development of future HIV-1 therapeutics to eradicate viral reservoirs from the brain.

scholarly journals Transport of Human Immunodeficiency Virus Type 1 Pseudoviruses across the Blood-Brain Barrier: Role of Envelope Proteins and Adsorptive Endocytosis

2001 ◽  
Vol 75 (10) ◽  
pp. 4681-4691 ◽  
Author(s):  
William A. Banks ◽  
Eric O. Freed ◽  
Kathleen M. Wolf ◽  
Sandra M. Robinson ◽  
Mark Franko ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Envelope Proteins ◽  
Free Virus ◽  
Immunodeficiency Virus ◽  
The Brain ◽  
Adsorptive Endocytosis ◽  
Hiv 1

ABSTRACT Blood-borne human immunodeficiency virus type 1 (HIV-1) crosses the blood-brain barrier (BBB) to induce brain dysfunction. How HIV-1 crosses the BBB is unclear. Most work has focused on the ability of infected immune cells to cross the BBB, with less attention devoted to the study of free virus. Since the HIV-1 coat glycoprotein gp120 can cross the BBB, we postulated that gp120 might be key in determining whether free virus can cross the BBB. We used radioactive virions which do (Env+) or do not (Env−) bear the envelope proteins to characterize the ability of HIV-1 to be taken up by the murine BBB. In vivo and in vitro studies showed that the envelope proteins are key to the uptake of free virus and that uptake was enhanced by wheat germ agglutinin, strongly suggesting that the envelope proteins induce viral adsorptive endocytosis and transcytosis in brain endothelia. Capillary depletion showed that Env+virus completely crossed the vascular BBB to enter the parenchyma of the brain. Virus also entered the cerebrospinal fluid, suggesting passage across the choroid plexus as well. About 0.22% of the intravenously injected dose was taken up per g of brain. In vitro studies showed that postinternalization membrane cohesion (membrane binding not reversed with acid wash or cell lysis) was a regulated event. Intact virus was recovered from the brain endothelial cytosol and was effluxed from the endothelial cells. These results show that free HIV-1 can cross the BBB by an event related to adsorptive endocytosis and mediated by the envelope proteins.

scholarly journals Tissue-Specific Sequence Alterations in the Human Immunodeficiency Virus Type 1 Envelope Favoring CCR5 Usage Contribute to Persistence of Dual-Tropic Virus in the Brain

2009 ◽  
Vol 83 (11) ◽  
pp. 5430-5441 ◽  
Author(s):  
Lachlan Gray ◽  
Michael Roche ◽  
Melissa J. Churchill ◽  
Jasminka Sterjovski ◽  
Anne Ellett ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Immunodeficiency Virus ◽  
N Terminus ◽  
The Brain ◽  
Ccr5 Usage ◽  
V3 Region ◽  
Hiv 1

ABSTRACT Most human immunodeficiency virus type 1 (HIV-1) strains isolated from the brain use CCR5 for entry into macrophages and microglia. Strains that use both CCR5 and CXCR4 for entry (R5X4 strains) have been identified in the brains of some individuals, but mechanisms underlying the persistence of R5X4 viruses compartmentalized between the brain and other tissue reservoirs are unknown. Here, we characterized changes in the HIV-1 envelope (Env) that enhance the tropism of R5X4 variants for brain or lymphoid tissue. R5X4 Envs derived from the brains of two individuals had enhanced CCR5 usage in fusion assays compared to R5X4 Envs derived from matched spleen or blood, which was associated with reduced dependence on specific residues in the CCR5 N terminus and extracellular loop 1 (ECL1) and ECL3 regions. In contrast, spleen/blood-derived Envs had enhanced CXCR4 usage compared to brain-derived Envs, which was associated with reduced dependence on residues in the CXCR4 N terminus and ECL2 region. Consequently, brain-derived Envs had preferential CCR5 usage for HIV-1 entry into the JC53 cell line, could use either CCR5 or CXCR4 for entry into monocyte-derived macrophages (MDM), and could use CCR5 (albeit inefficiently) for entry into peripheral blood mononuclear cells (PBMC), whereas the entry of spleen-derived Envs was CXCR4 dependent in all three cell types. Mutagenesis studies of Env amino acid variants influencing coreceptor usage showed that S306 in the gp120 V3 region of brain-derived Envs reduces dependence on the CCR5 N terminus and enhances CCR5 usage for HIV-1 entry into PBMC and MDM, whereas R306 in spleen-derived Envs reduces dependence on the CXCR4 N terminus and confers the CXCR4 restricted phenotype. These results identify mechanisms underlying R5X4 HIV-1 persistence in different tissue reservoirs. Tissue-specific changes in the gp120 V3 region that increase the efficiency of CCR5 or CXCR4 usage, and thereby influence coreceptor preference, may enhance the tropism of R5X4 strains for CCR5-expressing macrophage lineage cells in the brain and CXCR4-expressing T cells in lymphoid tissues, respectively.

scholarly journals Lentivirus Nef Specifically Activates Pak2

2000 ◽  
Vol 74 (23) ◽  
pp. 11081-11087 ◽  
Author(s):  
Vivek K. Arora ◽  
Rene P. Molina ◽  
John L. Foster ◽  
John L. Blakemore ◽  
Jonathan Chernoff ◽  
...  
Keyword(s):  
Caspase 3 ◽  
Cell Types ◽  
Serine Threonine Kinase ◽  
Immunodeficiency Virus ◽  
Multiple Cell ◽  
Different Cell Types ◽  
Hiv 1

ABSTRACT Nef proteins from human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV) have been found to associate with an active cellular serine/threonine kinase designated Nef-associated kinase (Nak). The exact identity of Nak remains controversial, with two recent studies indicating that Nak may be either Pak1 or Pak2. In this study, we investigated the hypothesis that such discrepancies arise from the use of different Nef alleles or different cell types by individual investigators. We first confirm that Pak2 but not Pak1 is cleaved by caspase 3 in vitro and then demonstrate that Nak is caspase 3 sensitive, regardless of Nef allele or cell type used. We testednef alleles from three lentiviruses (HIV-1 SF2, HIV-1 NL4-3, and SIVmac239) and used multiple cell lines of myeloid, lymphoid, and nonhematopoietic origin to evaluate the identity of Nak. We demonstrate that ectopically expressed Pak2 can substitute for Nak, while ectopically expressed Pak1 cannot. We then show that Nef specifically mediates the robust activation of ectopically expressed Pak2, directly demonstrating that Nef regulates Pak2 activity and does not merely associate with activated Pak2. We report that most of the active Pak2 is found bound to Nef, although a fraction is not. In contrast, only a small amount of Nef is found associated with Pak2. We conclude that Nak is Pak2 and that Nef specifically mediates Pak2 activation in a low-abundance complex. These results will facilitate both the elucidation of the role of Nef in pathogenesis and the development of specific inhibitors of this highly conserved function of Nef.

scholarly journals HIV-1 Gag-Pol Sequences from Ugandan Early Infections Reveal Sequence Variants Associated with Elevated Replication Capacity

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 171
Author(s):  
Anne Kapaata ◽  
Sheila N. Balinda ◽  
Rui Xu ◽  
Maria G. Salazar ◽  
Kimberly Herard ◽  
...  
Keyword(s):  
Protein Domain ◽  
Replication Capacity ◽  
Functional Protein ◽  
New Host ◽  
Single Genome ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Novel Protein

The ability to efficiently establish a new infection is a critical property for human immunodeficiency virus type 1 (HIV-1). Although the envelope protein of the virus plays an essential role in receptor binding and internalization of the infecting virus, the structural proteins, the polymerase and the assembly of new virions may also play a role in establishing and spreading viral infection in a new host. We examined Ugandan viruses from newly infected patients and focused on the contribution of the Gag-Pol genes to replication capacity. A panel of Gag-Pol sequences generated using single genome amplification from incident HIV-1 infections were cloned into a common HIV-1 NL4.3 pol/env backbone and the influence of Gag-Pol changes on replication capacity was monitored. Using a novel protein domain approach, we then documented diversity in the functional protein domains across the Gag-Pol region and identified differences in the Gag-p6 domain that were frequently associated with higher in vitro replication.

scholarly journals Structure, Function, and Interactions of the HIV-1 Capsid Protein

Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 100
Author(s):  
Eric Rossi ◽  
Megan E. Meuser ◽  
Camille J. Cunanan ◽  
Simon Cocklin
Keyword(s):  
Life Cycle ◽  
Capsid Protein ◽  
Adaptor Proteins ◽  
Restriction Factors ◽  
Gag Polyprotein ◽  
Immunodeficiency Virus ◽  
Host Cell Factors ◽  
Hiv 1

The capsid (CA) protein of the human immunodeficiency virus type 1 (HIV-1) is an essential structural component of a virion and facilitates many crucial life cycle steps through interactions with host cell factors. Capsid shields the reverse transcription complex from restriction factors while it enables trafficking to the nucleus by hijacking various adaptor proteins, such as FEZ1 and BICD2. In addition, the capsid facilitates the import and localization of the viral complex in the nucleus through interaction with NUP153, NUP358, TNPO3, and CPSF-6. In the later stages of the HIV-1 life cycle, CA plays an essential role in the maturation step as a constituent of the Gag polyprotein. In the final phase of maturation, Gag is cleaved, and CA is released, allowing for the assembly of CA into a fullerene cone, known as the capsid core. The fullerene cone consists of ~250 CA hexamers and 12 CA pentamers and encloses the viral genome and other essential viral proteins for the next round of infection. As research continues to elucidate the role of CA in the HIV-1 life cycle and the importance of the capsid protein becomes more apparent, CA displays potential as a therapeutic target for the development of HIV-1 inhibitors.

scholarly journals The Late-Domain-Containing Protein p6 Is the Predominant Phosphoprotein of Human Immunodeficiency Virus Type 1 Particles

2002 ◽  
Vol 76 (3) ◽  
pp. 1015-1024 ◽  
Author(s):  
Barbara Müller ◽  
Tilo Patschinsky ◽  
Hans-Georg Kräusslich
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Metabolic Labeling ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
A Minor ◽  
Hiv 1

ABSTRACT The Gag-derived protein p6 of human immunodeficiency virus type 1 (HIV-1) plays a crucial role in the release of virions from the membranes of infected cells. It is presumed that p6 and functionally related proteins from other viruses act as adapters, recruiting cellular factors to the budding site. This interaction is mediated by so-called late domains within the viral proteins. Previous studies had suggested that virus release from the plasma membrane shares elements with the cellular endocytosis machinery. Since protein phosphorylation is known to be a regulatory mechanism in these processes, we have investigated the phosphorylation of HIV-1 structural proteins. Here we show that p6 is the major phosphoprotein of HIV-1 particles. After metabolic labeling of infected cells with [ortho- 32P]phosphate, we found that phosphorylated p6 from infected cells and from virus particles consisted of several forms, suggesting differential phosphorylation at multiple sites. Apparently, phosphorylation occurred shortly before or after the release of p6 from Gag and involved only a minor fraction of the total virion-associated p6 molecules. Phosphoamino acid analysis indicated phosphorylation at Ser and Thr, as well as a trace of Tyr phosphorylation, supporting the conclusion that multiple phosphorylation events do occur. In vitro experiments using purified virus revealed that endogenous or exogenously added p6 was efficiently phosphorylated by virion-associated cellular kinase(s). Inhibition experiments suggested that a cyclin-dependent kinase or a related kinase, most likely ERK2, was involved in p6 phosphorylation by virion-associated enzymes.

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