scholarly journals Synergistic Impairment of the Neurovascular Unit by HIV-1 Infection and Methamphetamine Use: Implications for HIV-1-Associated Neurocognitive Disorders

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1883
Author(s):  
Nikolai Fattakhov ◽  
Silvia Torices ◽  
Michael Stangis ◽  
Minseon Park ◽  
Michal Toborek
Keyword(s):  
Molecular Mechanisms ◽  
Inflammatory Responses ◽  
Neurovascular Unit ◽  
Neuronal Injury ◽  
Peripheral Circulation ◽  
Neurocognitive Disorders ◽  
Methamphetamine Use ◽  
Neurocognitive Impairments ◽  
Immunodeficiency Virus ◽  
Hiv 1

The neurovascular units (NVU) are the minimal functional units of the blood­–brain barrier (BBB), composed of endothelial cells, pericytes, astrocytes, microglia, neurons, and the basement membrane. The BBB serves as an important interface for immune communication between the brain and peripheral circulation. Disruption of the NVU by the human immunodeficiency virus-1 (HIV-1) induces dysfunction of the BBB and triggers inflammatory responses, which can lead to the development of neurocognitive impairments collectively known as HIV-1-associated neurocognitive disorders (HAND). Methamphetamine (METH) use disorder is a frequent comorbidity among individuals infected with HIV-1. METH use may be associated not only with rapid HIV-1 disease progression but also with accelerated onset and increased severity of HAND. However, the molecular mechanisms of METH-induced neuronal injury and cognitive impairment in the context of HIV-1 infection are poorly understood. In this review, we summarize recent progress in the signaling pathways mediating synergistic impairment of the BBB and neuronal injury induced by METH and HIV-1, potentially accelerating the onset or severity of HAND in HIV-1-positive METH abusers. We also discuss potential therapies to limit neuroinflammation and NVU damage in HIV-1-infected METH abusers.

scholarly journals Interaction between the Human Immunodeficiency Virus Type 1 Gag Matrix Domain and Phosphatidylinositol-(4,5)-Bisphosphate Is Essential for Efficient Gag Membrane Binding

2007 ◽  
Vol 82 (5) ◽  
pp. 2405-2417 ◽  
Author(s):  
Vineela Chukkapalli ◽  
Ian B. Hogue ◽  
Vitaly Boyko ◽  
Wei-Shau Hu ◽  
Akira Ono
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Molecular Mechanisms ◽  
Membrane Binding ◽  
Particle Assembly ◽  
Immunodeficiency Virus ◽  
The Impact ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) particle assembly mediated by the viral structural protein Gag occurs predominantly on the plasma membrane (PM). Although it is known that the matrix (MA) domain of Gag plays a major role in PM localization, molecular mechanisms that determine the location of assembly remain to be elucidated. We observed previously that overexpression of polyphosphoinositide 5-phosphatase IV (5ptaseIV) that depletes PM phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2] impairs virus particle production and redirects processed Gag to intracellular compartments. In this study, we examined the impact of PI(4,5)P2 depletion on the subcellular localization of the entire Gag population using Gag-fluorescent protein chimeras. Upon 5ptaseIV overexpression, in addition to perinuclear localization, Gag also showed a hazy cytosolic signal, suggesting that PI(4,5)P2 depletion impairs Gag membrane binding. Indeed, Gag was less membrane bound in PI(4,5)P2-depleted cells, as assessed by biochemical analysis. These observations are consistent with the hypothesis that Gag interacts with PI(4,5)P2. To examine a putative Gag interaction with PI(4,5)P2, we developed an in vitro binding assay using full-length myristoylated Gag and liposome-associated PI(4,5)P2. Using this assay, we observed that PI(4,5)P2 significantly enhances liposome binding of wild-type Gag. In contrast, a Gag derivative lacking MA did not require PI(4,5)P2 for efficient liposome binding. To analyze the involvement of MA in PI(4,5)P2 binding further, we examined MA basic amino acid substitution mutants. These mutants, previously shown to localize in perinuclear compartments, bound PI(4,5)P2-containing liposomes weakly. Altogether, these results indicate that HIV-1 Gag binds PI(4,5)P2 on the membrane and that the MA basic domain mediates this interaction.

scholarly journals c-Myc and Sp1 Contribute to Proviral Latency by Recruiting Histone Deacetylase 1 to the Human Immunodeficiency Virus Type 1 Promoter

2007 ◽  
Vol 81 (20) ◽  
pp. 10914-10923 ◽  
Author(s):  
Guochun Jiang ◽  
Amy Espeseth ◽  
Daria J. Hazuda ◽  
David M. Margolis
Keyword(s):  
Human Immunodeficiency Virus ◽  
Rna Polymerase Ii ◽  
Histone Deacetylase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Molecular Mechanisms ◽  
Histone Deacetylase 1 ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Histone deacetylase (HDAC) inhibitors such as valproic acid (VPA) induce the expression of quiescent proviral human immunodeficiency virus type 1 (HIV-1) and may deplete proviral infection in vivo. To uncover novel molecular mechanisms that maintain HIV latency, we sought cellular mRNAs whose expression was diminished in resting CD4+ T cells of HIV-1-infected patients exposed to VPA. c-Myc was prominent among genes markedly downregulated upon exposure to VPA. c-Myc expression repressed HIV-1 expression in chronically infected cell lines. Chromatin immunoprecipitation (ChIP) assays revealed that c-Myc and HDAC1 are coordinately resident at the HIV-1 long terminal repeat (LTR) promoter and absent from the promoter after VPA treatment in concert with histone acetylation, RNA polymerase II recruitment, and LTR expression. Sequential ChIP assays demonstrated that c-Myc, Sp1, and HDAC1 coexist in the same DNA-protein complex at the HIV promoter. Short hairpin RNA inhibition of c-Myc reduces both c-Myc and HDAC1 occupancy, blocks c-Myc repression of Tat activation, and increases LTR expression. These results expand the understanding of mechanisms that recruit HDAC and maintain the latency of HIV-1, suggesting novel therapeutic approaches against latent proviral HIV infection.

scholarly journals Expression of Exogenous Sam68, the 68-Kilodalton Src-Associated Protein in Mitosis, Is Able To Alleviate Impaired Rev Function in Astrocytes

2002 ◽  
Vol 76 (9) ◽  
pp. 4526-4535 ◽  
Author(s):  
Jinliang Li ◽  
Ying Liu ◽  
In-Woo Park ◽  
Johnny J. He
Keyword(s):  
Gene Expression ◽  
Nuclear Export ◽  
Molecular Mechanisms ◽  
Subcellular Fractionation ◽  
Dominant Negative ◽  
Double Mutation ◽  
Gene Assay ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) gene expression in astrocytes is restricted, resulting in a brief and limited synthesis of HIV-1 viral structural proteins. Impaired Rev function has been documented in these cells. However, the molecular mechanisms underlying the impaired Rev function are not fully understood. Using the astroglial cell line U87.MG as a model, we report here that HIV-1 gene expression down-regulated expression of Sam68, the 68-kDa Src-associated protein in mitosis, which was constitutively expressed at a lower level in astrocytes. Elevating the endogenous level of Sam68 expression considerably restored HIV-1 Rev function in astrocytes, as determined by a Rev-dependent reporter gene assay. However, elevation of Sam68 expression achieved only a modest increase in HIV-1 production, further supporting the notion that there are multiple cellular restrictions of HIV-1 gene expression in astrocytes. Mutagenesis analysis identified the region between amino acids 321 and 410 of Sam68 as being directly involved in the binding of Sam68 to Rev, while a double mutation in Rev, L78D and E79L, like those in the dominant-negative Rev mutant M10, eliminated Rev binding to Sam68. Moreover, subcellular fractionation and digital fluorescence microscopic imaging revealed that Sam68 expression promoted Rev nuclear export. Taken together, our studies demonstrate that a lower level of constitutive Sam68 expression, followed by further down-regulation by HIV-1 infection, contributes to impaired Rev function in astrocytes, and they suggest that Sam68 may play an important role in Rev nuclear export.

scholarly journals Microglia: The Real Foe in HIV-1-Associated Neurocognitive Disorders?

Biomedicines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 925
Author(s):  
Ana Borrajo López ◽  
Maria Aránzazu Penedo ◽  
Tania Rivera-Baltanas ◽  
Daniel Pérez-Rodríguez ◽  
David Alonso-Crespo ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Target Cells ◽  
Current State ◽  
Immunodeficiency Virus ◽  
Combined Antiretroviral Therapy ◽  
The Central Nervous System ◽  
Infected Cells ◽  
Hiv 1 ◽  
New Strategies

The current use of combined antiretroviral therapy (cART) is leading to a significant decrease in deaths and comorbidities associated with human immunodeficiency virus type 1 (HIV-1) infection. Nonetheless, none of these therapies can extinguish the virus from the long-lived cellular reservoir, including microglia, thereby representing an important obstacle to curing HIV. Microglia are the foremost cells infected by HIV-1 in the central nervous system (CNS) and are believed to be involved in the development of HIV-1-associated neurocognitive disorder (HAND). At present, the pathological mechanisms contributing to HAND remain unclear, but evidence suggests that removing these infected cells from the brain, as well as obtaining a better understanding of the specific molecular mechanisms of HIV-1 latency in these cells, should help in the design of new strategies to prevent HAND and achieve a cure for these diseases. The goal of this review was to study the current state of knowledge of the neuropathology and research models of HAND containing virus susceptible target cells (microglial cells) and potential pharmacological treatment approaches under investigation.

scholarly journals TRIM28 promotes HIV-1 latency by SUMOylating CDK9 and inhibiting P-TEFb

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Xiancai Ma ◽  
Tao Yang ◽  
Yuewen Luo ◽  
Liyang Wu ◽  
Yawen Jiang ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Kinase Activity ◽  
Latent Reservoir ◽  
Functional Cure ◽  
Site Specific ◽  
Cyclin T1 ◽  
Immunodeficiency Virus ◽  
Cdk9 Kinase Activity ◽  
Hiv 1

Comprehensively elucidating the molecular mechanisms of human immunodeficiency virus type 1 (HIV-1) latency is a priority to achieve a functional cure. As current 'shock' agents failed to efficiently reactivate the latent reservoir, it is important to discover new targets for developing more efficient latency-reversing agents (LRAs). Here, we found that TRIM28 potently suppresses HIV-1 expression by utilizing both SUMO E3 ligase activity and epigenetic adaptor function. Through global site-specific SUMO-MS study and serial SUMOylation assays, we identified that P-TEFb catalytic subunit CDK9 is significantly SUMOylated by TRIM28 with SUMO4. The Lys44, Lys56 and Lys68 residues on CDK9 are SUMOylated by TRIM28, which inhibits CDK9 kinase activity or prevents P-TEFb assembly by directly blocking the interaction between CDK9 and Cyclin T1, subsequently inhibits viral transcription and contributes to HIV-1 latency. The manipulation of TRIM28 and its consequent SUMOylation pathway could be the target for developing LRAs.

scholarly journals Platelets in HIV: A Guardian of Host Defence or Transient Reservoir of the Virus?

2021 ◽  
Vol 12 ◽  
Author(s):  
Etheresia Pretorius
Keyword(s):  
Complex Formation ◽  
Inflammatory Responses ◽  
Envelope Proteins ◽  
Host Defence ◽  
Thrombotic Risk ◽  
Short Lifespan ◽  
Immunodeficiency Virus ◽  
Host Defence System ◽  
Inflammatory Molecules ◽  
Hiv 1

The immune and inflammatory responses of platelets to human immunodeficiency virus 1 (HIV-1) and its envelope proteins are of great significance to both the treatment of the infection, and to the comorbidities related to systemic inflammation. Platelets can interact with the HIV-1 virus itself, or with viral membrane proteins, or with dysregulated inflammatory molecules in circulation, ensuing from HIV-1 infection. Platelets can facilitate the inhibition of HIV-1 infection via endogenously-produced inhibitors of HIV-1 replication, or the virus can temporarily hide from the immune system inside platelets, whereby platelets act as HIV-1 reservoirs. Platelets are therefore both guardians of the host defence system, and transient reservoirs of the virus. Such reservoirs may be of particular significance during combination antiretroviral therapy (cART) interruption, as it may drive viral persistence, and result in significant implications for treatment. Both HIV-1 envelope proteins and circulating inflammatory molecules can also initiate platelet complex formation with immune cells and erythrocytes. Complex formation cause platelet hypercoagulation and may lead to an increased thrombotic risk. Ultimately, HIV-1 infection can initiate platelet depletion and thrombocytopenia. Because of their relatively short lifespan, platelets are important signalling entities, and could be targeted more directly during HIV-1 infection and cART.

The role of viral coreceptors and enhanced macrophage tropism in human immunodeficiency virus type 1 disease progression

Sexual Health ◽  
2004 ◽  
Vol 1 (1) ◽  
pp. 23 ◽  
Author(s):  
Paul R. Gorry ◽  
Jasminka Sterjovski ◽  
Melissa Churchill ◽  
Kristie Witlox ◽  
Lachlan Gray ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Disease Progression ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Molecular Mechanisms ◽  
Coreceptor Usage ◽  
Immunodeficiency Virus ◽  
The Impact ◽  
Hiv 1

Despite numerous studies on the impact of viral diversity, human immunodeficiency virus type 1 (HIV-1)-specific immune responses and host factors on disease progression, we still do not have a firm understanding of the long-term pathogenesis of HIV-1 infection. Rapid depletion of CD4+ T-lymphocytes has been associated with a switch in viral coreceptor usage from CCR5 to CXCR4 in ~40 to 50% of infected individuals. However, the majority of infected individuals who progress to AIDS harbour only CCR5-dependent (R5) viral strains. The progression HIV-1 disease is associated with an enhanced tropism of R5 viral strains for monocyte/macrophage lineage cells (enhanced M-tropism). However, the underlying molecular mechanisms contributing to enhanced M-tropism by R5 HIV-1 strains, and how HIV-1 variants with enhanced M-tropism cause CD4+ T-cell depletion in vivo are unknown. This review examines the relationship between viral coreceptor usage, M-tropism, and pathogenicity of HIV-1. We highlight evidence supporting the hypothesis that enhanced M-tropism of R5 HIV-1 results from adaptive viral evolution, resulting in HIV-1 variants that have increased ability to utilise relatively low levels of CCR5 expressed on macrophages, by way of increased CCR5 affinity. The evidence also suggests that these late-emerging, R5 viral strains have reduced sensitivity to entry inhibitors, and increased ability to cause CD4+ T-lymphocyte loss. These variants are likely to impact HIV-1 disease progression, especially in patients who persistently harbour only R5 viral strains.

scholarly journals Vpu Directs the Degradation of the Human Immunodeficiency Virus Restriction Factor BST-2/Tetherin via a βTrCP-Dependent Mechanism

2009 ◽  
Vol 83 (16) ◽  
pp. 7931-7947 ◽  
Author(s):  
Janet L. Douglas ◽  
Kasinath Viswanathan ◽  
Matthew N. McCarroll ◽  
Jean K. Gustin ◽  
Klaus Früh ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Molecular Mechanisms ◽  
Cellular Protein ◽  
Dependent Manner ◽  
Wild Type ◽  
Concanamycin A ◽  
Virion Release ◽  
Early Endosomes ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The primary roles attributed to the human immunodeficiency virus type 1 (HIV-1) Vpu protein are the degradation of the viral receptor CD4 and the enhancement of virion release. With regard to CD4 downregulation, Vpu has been shown to act as an adapter linking CD4 with the ubiquitin-proteasome machinery via interaction with the F-box protein βTrCP. To identify additional cellular βTrCP-dependent Vpu targets, we performed quantitative proteomics analyses using the plasma membrane fraction of HeLa cells expressing either wild-type Vpu or a Vpu mutant (S52N/S56N) that does not bind βTrCP. One cellular protein, BST-2 (CD317), was consistently underrepresented in the membrane proteome of cells expressing wild-type Vpu compared to the proteome of cells expressing the Vpu mutant. To verify the biological relevance of this phenotype for HIV pathogenesis, we showed that in T cells infected with HIV-1, BST-2 downregulation occurred in a Vpu-dependent manner. Recently, BST-2 has been identified as the interferon-inducible cellular factor Tetherin, which restricts HIV virion release in the absence of Vpu. We address here the unresolved mechanism of Vpu-mediated BST-2 downregulation. Our data show that the presence of wild-type Vpu reduced cell surface and total steady-state BST-2 levels, whereas that of the mutant Vpu had no effect. In addition, treatment of cells with the lysosome acidification inhibitor concanamycin A, but not treatment with the proteasome inhibitor MG132, reduced BST-2 downregulation by wild-type Vpu, thereby suggesting that the presence of Vpu leads to the degradation of BST-2 via an endosome-lysosome degradation pathway. The importance of βTrCP in this process was confirmed by demonstrating that in the absence of βTrCP, BST-2 levels were restored despite the presence of Vpu. Taken together, these data support the hypothesis that, in similarity to its role in CD4 degradation, Vpu acts as an adapter molecule linking BST-2 to the cellular ubiquitination machinery via βTrCP. However, in contrast to the proteasome-dependent degradation of CD4, which occurs in the endoplasmic reticulum, Vpu appears to interact with BST-2 in the trans-Golgi network or in early endosomes, leading to lysosomal degradation of BST-2. Via this action, Vpu could counter the tethering function of BST-2, resulting in enhanced HIV-1 virion release. Interestingly, although HIV-2 does not express Vpu, an isolate known to exhibit enhanced viral egress can downregulate surface BST-2 by an as-yet-unknown mechanism that does not appear to involve degradation. Understanding the molecular mechanisms of both Vpu-dependent and -independent mediated antagonism of BST-2 will be critical for therapeutic strategies that exploit this novel viral function.

scholarly journals Benzodiazepines Drive Alteration of Chromatin at the Integrated HIV-1 LTR

Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 191
Author(s):  
Weam Elbezanti ◽  
Angel Lin ◽  
Alexis Schirling ◽  
Alexandria Jackson ◽  
Matthew Marshall ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Chromatin Immunoprecipitation ◽  
Molecular Mechanisms ◽  
Transcriptional Silencing ◽  
Latent Reservoir ◽  
Prior Work ◽  
Immunodeficiency Virus ◽  
Runx Proteins ◽  
Hiv 1

Antiretroviral therapy (ART) lowers human immunodeficiency virus type 1 (HIV-1) viral load to undetectable levels, but does not eliminate the latent reservoir. One of the factors controlling the latent reservoir is transcriptional silencing of the integrated HIV-1 long terminal repeat (LTR). The molecular mechanisms that control HIV-1 transcription are not completely understood. We have previously shown that RUNX1, a host transcription factor, may play a role in the establishment and maintenance of HIV-1 latency. Prior work has demonstrated that inhibition of RUNX1 by the benzodiazepine (BDZ) Ro5-3335 synergizes with suberanilohydroxamic acid (SAHA) to activate HIV-1 transcription. In this current work, we examine the effect of RUNX1 inhibition on the chromatin state of the integrated HIV-1 LTR. Using chromatin immunoprecipitation (ChIP), we found that Ro5-3335 significantly increased the occupancy of STAT5 at the HIV-1 LTR. We also screened other BDZs for their ability to regulate HIV-1 transcription and demonstrate their ability to increase transcription and alter chromatin at the LTR without negatively affecting Tat activity. These findings shed further light on the mechanism by which RUNX proteins control HIV-1 transcription and suggest that BDZ compounds might be useful in activating HIV-1 transcription through STAT5 recruitment to the HIV-1 LTR.

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