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Yuan NY, Medders KE, Sanchez AB, Shah R, de Rozieres CM, Ojeda-Juárez D, Maung R, Williams R, Gelman BB, Baaten BJ, Roberts AJ, Kaul M. A critical role for Macrophage-derived Cysteinyl-Leukotrienes in HIV-1 induced neuronal injury. Brain Behav Immun 2024; 118:149-166. [PMID: 38423397 PMCID: PMC11173376 DOI: 10.1016/j.bbi.2024.02.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 01/26/2024] [Accepted: 02/21/2024] [Indexed: 03/02/2024] Open
Abstract
Macrophages (MΦ) infected with human immunodeficiency virus (HIV)-1 or activated by its envelope protein gp120 exert neurotoxicity. We found previously that signaling via p38 mitogen-activated protein kinase (p38 MAPK) is essential to the neurotoxicity of HIVgp120-stimulated MΦ. However, the associated downstream pathways remained elusive. Here we show that cysteinyl-leukotrienes (CysLT) released by HIV-infected or HIVgp120 stimulated MΦ downstream of p38 MAPK critically contribute to neurotoxicity. SiRNA-mediated or pharmacological inhibition of p38 MAPK deprives MΦ of CysLT synthase (LTC4S) and, pharmacological inhibition of the cysteinyl-leukotriene receptor 1 (CYSLTR1) protects cerebrocortical neurons against toxicity of both gp120-stimulated and HIV-infected MΦ. Components of the CysLT pathway are differentially regulated in brains of HIV-infected individuals and a transgenic mouse model of NeuroHIV (HIVgp120tg). Moreover, genetic ablation of LTC4S or CysLTR1 prevents neuronal damage and impairment of spatial memory in HIVgp120tg mice. Altogether, our findings suggest a novel critical role for cysteinyl-leukotrienes in HIV-associated brain injury.
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Affiliation(s)
- Nina Y Yuan
- University of California Riverside, School of Medicine, Division of Biomedical Sciences, 900 University Ave, Riverside, CA 92521, USA.
| | - Kathryn E Medders
- Sanford Burnham Prebys Medical Discovery Institute, Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Ana B Sanchez
- Sanford Burnham Prebys Medical Discovery Institute, Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Rohan Shah
- University of California Riverside, School of Medicine, Division of Biomedical Sciences, 900 University Ave, Riverside, CA 92521, USA.
| | - Cyrus M de Rozieres
- Sanford Burnham Prebys Medical Discovery Institute, Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Daniel Ojeda-Juárez
- University of California Riverside, School of Medicine, Division of Biomedical Sciences, 900 University Ave, Riverside, CA 92521, USA; Sanford Burnham Prebys Medical Discovery Institute, Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Ricky Maung
- University of California Riverside, School of Medicine, Division of Biomedical Sciences, 900 University Ave, Riverside, CA 92521, USA; Sanford Burnham Prebys Medical Discovery Institute, Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Roy Williams
- Sanford Burnham Prebys Medical Discovery Institute, Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Benjamin B Gelman
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555-0419 USA; Department of Neurobiology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555-0419 USA.
| | - Bas J Baaten
- Sanford Burnham Prebys Medical Discovery Institute, Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Amanda J Roberts
- Animal Models Core, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Marcus Kaul
- University of California Riverside, School of Medicine, Division of Biomedical Sciences, 900 University Ave, Riverside, CA 92521, USA; Sanford Burnham Prebys Medical Discovery Institute, Infectious and Inflammatory Disease Center, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
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2
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Nickoloff-Bybel EA, Festa L, Meucci O, Gaskill PJ. Co-receptor signaling in the pathogenesis of neuroHIV. Retrovirology 2021; 18:24. [PMID: 34429135 PMCID: PMC8385912 DOI: 10.1186/s12977-021-00569-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 08/11/2021] [Indexed: 12/13/2022] Open
Abstract
The HIV co-receptors, CCR5 and CXCR4, are necessary for HIV entry into target cells, interacting with the HIV envelope protein, gp120, to initiate several signaling cascades thought to be important to the entry process. Co-receptor signaling may also promote the development of neuroHIV by contributing to both persistent neuroinflammation and indirect neurotoxicity. But despite the critical importance of CXCR4 and CCR5 signaling to HIV pathogenesis, there is only one therapeutic (the CCR5 inhibitor Maraviroc) that targets these receptors. Moreover, our understanding of co-receptor signaling in the specific context of neuroHIV is relatively poor. Research into co-receptor signaling has largely stalled in the past decade, possibly owing to the complexity of the signaling cascades and functions mediated by these receptors. Examining the many signaling pathways triggered by co-receptor activation has been challenging due to the lack of specific molecular tools targeting many of the proteins involved in these pathways and the wide array of model systems used across these experiments. Studies examining the impact of co-receptor signaling on HIV neuropathogenesis often show activation of multiple overlapping pathways by similar stimuli, leading to contradictory data on the effects of co-receptor activation. To address this, we will broadly review HIV infection and neuropathogenesis, examine different co-receptor mediated signaling pathways and functions, then discuss the HIV mediated signaling and the differences between activation induced by HIV and cognate ligands. We will assess the specific effects of co-receptor activation on neuropathogenesis, focusing on neuroinflammation. We will also explore how the use of substances of abuse, which are highly prevalent in people living with HIV, can exacerbate the neuropathogenic effects of co-receptor signaling. Finally, we will discuss the current state of therapeutics targeting co-receptors, highlighting challenges the field has faced and areas in which research into co-receptor signaling would yield the most therapeutic benefit in the context of HIV infection. This discussion will provide a comprehensive overview of what is known and what remains to be explored in regard to co-receptor signaling and HIV infection, and will emphasize the potential value of HIV co-receptors as a target for future therapeutic development. ![]()
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Affiliation(s)
- E A Nickoloff-Bybel
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - L Festa
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, 240 S. 40th Street, Philadelphia, PA, 19104, USA
| | - O Meucci
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.,Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, 19102, USA
| | - P J Gaskill
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.
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Kruize Z, Kootstra NA. The Role of Macrophages in HIV-1 Persistence and Pathogenesis. Front Microbiol 2019; 10:2828. [PMID: 31866988 PMCID: PMC6906147 DOI: 10.3389/fmicb.2019.02828] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/21/2019] [Indexed: 12/12/2022] Open
Abstract
Current antiretroviral therapy (ART) effectively suppresses Human Immunodeficiency Virus type 1 (HIV-1) in infected individuals. However, even long term ART does not eradicate HIV-1 infected cells and the virus persists in cellular reservoirs. Beside memory CD4+ T cells, cells of the myeloid lineage, especially macrophages, are believed to be an important sanctuary for HIV-1. Monocytes and macrophages are key players in the innate immune response to pathogens and are recruited to sites of infection and inflammation. Due to their long life span and ability to reside in virtually every tissue, macrophages have been proposed to play a critical role in the establishment and persistence of the HIV-1 reservoir. Current HIV-1 cure strategies mainly focus on the concept of “shock and kill” to purge the viral reservoir. This approach aims to reactivate viral protein production in latently infected cells, which subsequently are eliminated as a consequence of viral replication, or recognized and killed by the immune system. Macrophage susceptibility to HIV-1 infection is dependent on the local microenvironment, suggesting that molecular pathways directing differentiation and polarization are involved. Current latency reversing agents (LRA) are mainly designed to reactivate the HIV-1 provirus in CD4+ T cells, while their ability to abolish viral latency in macrophages is largely unknown. Moreover, the resistance of macrophages to HIV-1 mediated kill and the presence of infected macrophages in immune privileged regions including the central nervous system (CNS), may pose a barrier to elimination of infected cells by current “shock and kill” strategies. This review focusses on the role of monocytes/macrophages in HIV-1 persistence. We will discuss mechanisms of viral latency and persistence in monocytes/macrophages. Furthermore, the role of these cells in HIV-1 tissue distribution and pathogenesis will be discussed.
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Affiliation(s)
- Zita Kruize
- Laboratory for Viral Immune Pathogenesis, Department of Experimental Immunology, Amsterdam UMC, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, Netherlands
| | - Neeltje A Kootstra
- Laboratory for Viral Immune Pathogenesis, Department of Experimental Immunology, Amsterdam UMC, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, Netherlands
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4
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Abstract
Current antiretroviral therapy (ART) effectively suppresses Human Immunodeficiency Virus type 1 (HIV-1) in infected individuals. However, even long term ART does not eradicate HIV-1 infected cells and the virus persists in cellular reservoirs. Beside memory CD4+ T cells, cells of the myeloid lineage, especially macrophages, are believed to be an important sanctuary for HIV-1. Monocytes and macrophages are key players in the innate immune response to pathogens and are recruited to sites of infection and inflammation. Due to their long life span and ability to reside in virtually every tissue, macrophages have been proposed to play a critical role in the establishment and persistence of the HIV-1 reservoir. Current HIV-1 cure strategies mainly focus on the concept of "shock and kill" to purge the viral reservoir. This approach aims to reactivate viral protein production in latently infected cells, which subsequently are eliminated as a consequence of viral replication, or recognized and killed by the immune system. Macrophage susceptibility to HIV-1 infection is dependent on the local microenvironment, suggesting that molecular pathways directing differentiation and polarization are involved. Current latency reversing agents (LRA) are mainly designed to reactivate the HIV-1 provirus in CD4+ T cells, while their ability to abolish viral latency in macrophages is largely unknown. Moreover, the resistance of macrophages to HIV-1 mediated kill and the presence of infected macrophages in immune privileged regions including the central nervous system (CNS), may pose a barrier to elimination of infected cells by current "shock and kill" strategies. This review focusses on the role of monocytes/macrophages in HIV-1 persistence. We will discuss mechanisms of viral latency and persistence in monocytes/macrophages. Furthermore, the role of these cells in HIV-1 tissue distribution and pathogenesis will be discussed.
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Affiliation(s)
- Zita Kruize
- Laboratory for Viral Immune Pathogenesis, Department of Experimental Immunology, Amsterdam UMC, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, Netherlands
| | - Neeltje A Kootstra
- Laboratory for Viral Immune Pathogenesis, Department of Experimental Immunology, Amsterdam UMC, Amsterdam Infection & Immunity Institute, University of Amsterdam, Amsterdam, Netherlands
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Abstract
Infection with Human Immunodeficiency Virus (HIV)-1 continues to cause HIV-associated neurocognitive disorders despite combined antiretroviral therapy. Interferons (IFNs) are important for any antiviral immune response, but the lasting production of IFNα causes exhaustive activation leading eventually to progression to AIDS. Expression of IFNα in the HIV-exposed central nervous system has been linked to cognitive impairment and inflammatory neuropathology. In contrast, IFNβ exerts anti-inflammatory effects, appears to control, at least temporarily, lentiviral infection in the brain and provides neuroprotection. The dichotomy of type I IFN effects on HIV-1 infection and the associated brain injury will be discussed in this review, because the underlying mechanisms require further investigation to allow harnessing these innate immune factors for therapeutic purposes.
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Affiliation(s)
- Victoria E Thaney
- 1 Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute , La Jolla, California
| | - Marcus Kaul
- 1 Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute , La Jolla, California.,2 Division of Biomedical Sciences, School of Medicine, University of California , Riverside, Riverside, California
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6
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Thaney VE, O'Neill AM, Hoefer MM, Maung R, Sanchez AB, Kaul M. IFNβ Protects Neurons from Damage in a Murine Model of HIV-1 Associated Brain Injury. Sci Rep 2017; 7:46514. [PMID: 28425451 PMCID: PMC5397848 DOI: 10.1038/srep46514] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 03/17/2017] [Indexed: 12/17/2022] Open
Abstract
Infection with human immunodeficiency virus-1 (HIV-1) causes brain injury. Type I interferons (IFNα/β) are critical mediators of any anti-viral immune response and IFNβ has been implicated in the temporary control of lentiviral infection in the brain. Here we show that transgenic mice expressing HIV-1 envelope glycoprotein 120 in their central nervous system (HIVgp120tg) mount a transient IFNβ response and provide evidence that IFNβ confers neuronal protection against HIVgp120 toxicity. In cerebrocortical cell cultures, neuroprotection by IFNβ against gp120 toxicity is dependent on IFNα receptor 1 (IFNAR1) and the β-chemokine CCL4, as IFNAR1 deficiency and neutralizing antibodies against CCL4, respectively, abolish the neuroprotective effects. We find in vivo that IFNβ mRNA is significantly increased in HIVgp120tg brains at 1.5, but not 3 or 6 months of age. However, a four-week intranasal IFNβ treatment of HIVgp120tg mice starting at 3.5 months of age increases expression of CCL4 and concomitantly protects neuronal dendrites and pre-synaptic terminals in cortex and hippocampus from gp120-induced damage. Moreover, in vivo and in vitro data suggests astrocytes are a major source of IFNβ-induced CCL4. Altogether, our results suggest exogenous IFNβ as a neuroprotective factor that has potential to ameliorate in vivo HIVgp120-induced brain injury.
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Affiliation(s)
- Victoria E Thaney
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.,Graduate School of Biomedical Sciences, Sanford-Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Alan M O'Neill
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Melanie M Hoefer
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Ricky Maung
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Ana B Sanchez
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Marcus Kaul
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.,Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, San Diego, CA 92093, USA
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7
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Sanchez AB, Kaul M. Neuronal Stress and Injury Caused by HIV-1, cART and Drug Abuse: Converging Contributions to HAND. Brain Sci 2017; 7:brainsci7030025. [PMID: 28241493 PMCID: PMC5366824 DOI: 10.3390/brainsci7030025] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 02/15/2017] [Accepted: 02/20/2017] [Indexed: 12/21/2022] Open
Abstract
Multiple mechanisms appear to contribute to neuronal stress and injury underlying HIV-associated neurocognitive disorders (HAND), which occur despite the successful introduction of combination antiretroviral therapy (cART). Evidence is accumulating that components of cART can itself be neurotoxic upon long-term exposure. In addition, abuse of psychostimulants, such as methamphetamine (METH), seems to compromise antiretroviral therapy and aggravate HAND. However, the combined effect of virus and recreational and therapeutic drugs on the brain is still incompletely understood. However, several lines of evidence suggest a shared critical role of oxidative stress, compromised neuronal energy homeostasis and autophagy in promotion and prevention of neuronal dysfunction associated with HIV-1 infection, cART and psychostimulant use. In this review, we present a synopsis of recent work related to neuronal stress and injury induced by HIV infection, antiretrovirals (ARVs) and the highly addictive psychostimulant METH.
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Affiliation(s)
- Ana B Sanchez
- Immunity and Pathogenesis Program, Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.
| | - Marcus Kaul
- Immunity and Pathogenesis Program, Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.
- Department of Psychiatry, University of California San Diego, San Diego, CA 92093, USA.
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Monocyte-lymphocyte fusion induced by the HIV-1 envelope generates functional heterokaryons with an activated monocyte-like phenotype. Exp Cell Res 2017; 352:9-19. [PMID: 28132881 DOI: 10.1016/j.yexcr.2017.01.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 01/23/2017] [Accepted: 01/25/2017] [Indexed: 02/08/2023]
Abstract
Enveloped viruses induce cell-cell fusion when infected cells expressing viral envelope proteins interact with target cells, or through the contact of cell-free viral particles with adjoining target cells. CD4+ T lymphocytes and cells from the monocyte-macrophage lineage express receptors for HIV envelope protein. We have previously reported that lymphoid Jurkat T cells expressing the HIV-1 envelope protein (Env) can fuse with THP-1 monocytic cells, forming heterokaryons with a predominantly myeloid phenotype. This study shows that the expression of monocytic markers in heterokaryons is stable, whereas the expression of lymphoid markers is mostly lost. Like THP-1 cells, heterokaryons exhibited FcγR-dependent phagocytic activity and showed an enhanced expression of the activation marker ICAM-1 upon stimulation with PMA. In addition, heterokaryons showed morphological changes compatible with maturation, and high expression of the differentiation marker CD11b in the absence of differentiation-inducing agents. No morphological change nor increase in CD11b expression were observed when an HIV-fusion inhibitor blocked fusion, or when THP-1 cells were cocultured with Jurkat cells expressing a non-fusogenic Env protein, showing that differentiation was not induced merely by cell-cell interaction but required cell-cell fusion. Inhibition of TLR2/TLR4 signaling by a TIRAP inhibitor greatly reduced the expression of CD11b in heterokaryons. Thus, lymphocyte-monocyte heterokaryons induced by HIV-1 Env are stable and functional, and fusion prompts a phenotype characteristic of activated monocytes via intracellular TLR2/TLR4 signaling.
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Chauhan PS, Misra UK, Kalita J. A study of glutamate levels, NR1, NR2A, NR2B receptors and oxidative stress in rat model of Japanese encephalitis. Physiol Behav 2017; 171:256-267. [PMID: 28108334 DOI: 10.1016/j.physbeh.2017.01.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 01/16/2017] [Accepted: 01/16/2017] [Indexed: 11/15/2022]
Abstract
There is paucity of studies on the role of glutamate excitotoxicity in cell damage in Japanese encephalitis. In this study the glutamate levels and its NMDA receptors, and oxidative stress markers in different brain regions have been evaluated and correlated with neurobehavioral changes at different time points. Twelve day old Wistar rats were inoculated with 3×106pfu/ml intracerebrally. The neurobehavioral effects were evaluated by spontaneous locomotor activity (SLA), grip strength and rota rod test on 10, 33 and 48days post inoculation (dpi). Glutamate level was evaluated by enzyme linked immunosorbent assay, mRNA gene expression of ionotropic glutamate receptors N-methyl d-aspartate (NMDA) receptor 1, 2A and 2B (NR1, NR2A and NR2B) were evaluated by real time PCR. Malondialdehyde (MDA), glutathione (GSH) and glutathione peroxidase (GPx) levels were measured by spectrophotometer in different brain regions of JEV infected rats on 10, 33 and 48dpi. There was significant increase in motor deficit, grip strength and decreased locomotor activity on 10 and 33dpi. Glutamate levels were increased in thalamus, midbrain, frontal cortex, striatum and cerebellum on 10 and 33dpi and were followed by a recovery on 48dpi. Glutamate NMDR receptors NR1, NR2A and NR2B were reduced in thalamus, midbrain, frontal cortex, striatum and cerebellum on 10dpi which was followed by recovery after 33dpi. A significant increase in MDA level in thalamus, midbrain, frontal cortex, striatum and cerebellum was noted on 10 and 33dpi. The antioxidant GSH and GPx were significantly reduced in these brain regions on 10 and 33dpi. Glutamate, MDA, GSH and GPx correlated in different brain regions as the disease progress. Increased Glutamate level may be related to oxidative stress and may be responsible for behavioral alterations in rat model of Japanese encephalitis.
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Affiliation(s)
- Prashant Singh Chauhan
- Department of Neurology, Sanjay Gandhi Postgraduate Institute of Medical Science, Raebareily Road, Lucknow, India
| | - Usha Kant Misra
- Department of Neurology, Sanjay Gandhi Postgraduate Institute of Medical Science, Raebareily Road, Lucknow, India.
| | - Jayantee Kalita
- Department of Neurology, Sanjay Gandhi Postgraduate Institute of Medical Science, Raebareily Road, Lucknow, India
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10
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Spranger M, Fontana A. REVIEW ■ : Activation of Microglia: A Dangerous Interlude in Immune Function in the Brain. Neuroscientist 2016. [DOI: 10.1177/107385849600200515] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Microglial cells are representatives of the immune system in the CNS parenchyma. Their most characteristic property is their ability to modify their behavior in response to diverse signals from other cells in a variety of experimental conditions and human diseases, both acute and chronic. The transformation from a quiescent state into phagocytic brain macrophages is under strict control and accompanied by the production of several secretory products. These include cytokines, excitatory amino acids, and reactive oxygen metabolites by which the activated microglial cells correspond with other cells of the brain and immune system. Thus, they represent an essential host defense and repair system, and may be responsible for tissue destruction and neuronal death, depending on the balance of activating and inhibitory signals. NEUROSCIENTIST 2:293-299, 1996
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Antiretrovirals, Methamphetamine, and HIV-1 Envelope Protein gp120 Compromise Neuronal Energy Homeostasis in Association with Various Degrees of Synaptic and Neuritic Damage. Antimicrob Agents Chemother 2015; 60:168-79. [PMID: 26482305 DOI: 10.1128/aac.01632-15] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 10/12/2015] [Indexed: 01/06/2023] Open
Abstract
HIV-1 infection frequently causes HIV-associated neurocognitive disorders (HAND) despite combination antiretroviral therapy (cART). Evidence is accumulating that components of cART can themselves be neurotoxic upon long-term exposure. In addition, abuse of psychostimulants, such as methamphetamine, seems to aggravate HAND and compromise antiretroviral therapy. However, the combined effect of virus and recreational and therapeutic drugs on the brain is poorly understood. Therefore, we exposed mixed neuronal-glial cerebrocortical cells to antiretrovirals (ARVs) (zidovudine [AZT], nevirapine [NVP], saquinavir [SQV], and 118-D-24) of four different pharmacological categories and to methamphetamine and, in some experiments, the HIV-1 gp120 protein for 24 h and 7 days. Subsequently, we assessed neuronal injury by fluorescence microscopy, using specific markers for neuronal dendrites and presynaptic terminals. We also analyzed the disturbance of neuronal ATP levels and assessed the involvement of autophagy by using immunofluorescence and Western blotting. ARVs caused alterations of neurites and presynaptic terminals primarily during the 7-day incubation and depending on the specific compounds and their combinations with and without methamphetamine. Similarly, the loss of neuronal ATP was context specific for each of the drugs or combinations thereof, with and without methamphetamine or viral gp120. Loss of ATP was associated with activation of AMP-activated protein kinase (AMPK) and autophagy, which, however, failed to restore normal levels of neuronal ATP. In contrast, boosting autophagy with rapamycin prevented the long-term drop of ATP during exposure to cART in combination with methamphetamine or gp120. Our findings indicate that the overall positive effect of cART on HIV infection is accompanied by detectable neurotoxicity, which in turn may be aggravated by methamphetamine.
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12
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Monocytes as regulators of inflammation and HIV-related comorbidities during cART. J Immunol Res 2014; 2014:569819. [PMID: 25025081 PMCID: PMC4082935 DOI: 10.1155/2014/569819] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 05/15/2014] [Indexed: 12/17/2022] Open
Abstract
Combined antiretroviral therapy (cART) extends the lifespan and the quality of life for HIV-infected persons but does not completely eliminate chronic immune activation and inflammation. The low level of chronic immune activation persisting during cART-treated HIV infection is associated with the development of diseases which usually occur in the elderly. Although T-cell activation has been extensively examined in the context of cART-treated HIV infection, monocyte activation is only beginning to be recognized as an important source of inflammation in this context. Here we examine markers and sources of monocyte activation during cART-treated HIV infection and discuss the role of monocytes during cardiovascular disease, HIV-associated neurocognitive disorder, and innate immune aging.
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Abstract
Central nervous system (CNS) infections—i.e., infections involving the brain (cerebrum and cerebellum), spinal cord, optic nerves, and their covering membranes—are medical emergencies that are associated with substantial morbidity, mortality, or long-term sequelae that may have catastrophic implications for the quality of life of affected individuals. Acute CNS infections that warrant neurointensive care (ICU) admission fall broadly into three categories—meningitis, encephalitis, and abscesses—and generally result from blood-borne spread of the respective microorganisms. Other causes of CNS infections include head trauma resulting in fractures at the base of the skull or the cribriform plate that can lead to an opening between the CNS and the sinuses, mastoid, the middle ear, or the nasopharynx. Extrinsic contamination of the CNS can occur intraoperatively during neurosurgical procedures. Also, implanted medical devices or adjunct hardware (e.g., shunts, ventriculostomies, or external drainage tubes) and congenital malformations (e.g., spina bifida or sinus tracts) can become colonized and serve as sources or foci of infection. Viruses, such as rabies, herpes simplex virus, or polioviruses, can spread to the CNS via intraneural pathways resulting in encephalitis. If infection occurs at sites (e.g., middle ear or mastoid) contiguous with the CNS, infection may spread directly into the CNS causing brain abscesses; alternatively, the organism may reach the CNS indirectly via venous drainage or the sheaths of cranial and spinal nerves. Abscesses also may become localized in the subdural or epidural spaces. Meningitis results if bacteria spread directly from an abscess to the subarachnoid space. CNS abscesses may be a result of pyogenic meningitis or from septic emboli associated with endocarditis, lung abscess, or other serious purulent infections. Breaches of the blood–brain barrier (BBB) can result in CNS infections. Causes of such breaches include damage (e.g., microhemorrhage or necrosis of surrounding tissue) to the BBB; mechanical obstruction of microvessels by parasitized red blood cells, leukocytes, or platelets; overproduction of cytokines that degrade tight junction proteins; or microbe-specific interactions with the BBB that facilitate transcellular passage of the microorganism. The microorganisms that cause CNS infections include a wide range of bacteria, mycobacteria, yeasts, fungi, viruses, spirochaetes (e.g., neurosyphilis), and parasites (e.g., cerebral malaria and strongyloidiasis). The clinical picture of the various infections can be nonspecific or characterized by distinct, recognizable clinical syndromes. At some juncture, individuals with severe acute CNS infections require critical care management that warrants neuro-ICU admission. The implications for CNS infections are serious and complex and include the increased human and material resources necessary to manage very sick patients, the difficulties in triaging patients with vague or mild symptoms, and ascertaining the precise cause and degree of CNS involvement at the time of admission to the neuro-ICU. This chapter addresses a wide range of severe CNS infections that are better managed in the neuro-ICU. Topics covered include the medical epidemiology of the respective CNS infection; discussions of the relevant neuroanatomy and blood supply (essential for understanding the pathogenesis of CNS infections) and pathophysiology; symptoms and signs; diagnostic procedures, including essential neuroimaging studies; therapeutic options, including empirical therapy where indicated; and the perennial issue of the utility and effectiveness of steroid therapy for certain CNS infections. Finally, therapeutic options and alternatives are discussed, including the choices of antimicrobial agents best able to cross the BBB, supportive therapy, and prognosis.
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Affiliation(s)
- A Joseph Layon
- Pulmonary and Critical Care Medicine, Geisinger Health System, Danville, Pennsylvania USA
| | - Andrea Gabrielli
- Departments of Anesthesiology & Surgery, University of Florida College of Medicine, Gainesville, Florida USA
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Cisneros IE, Ghorpade A. HIV-1, methamphetamine and astrocyte glutamate regulation: combined excitotoxic implications for neuro-AIDS. Curr HIV Res 2012; 10:392-406. [PMID: 22591363 PMCID: PMC3580828 DOI: 10.2174/157016212802138832] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 04/18/2012] [Accepted: 04/18/2012] [Indexed: 02/08/2023]
Abstract
Glutamate, the most abundant excitatory transmitter in the brain can lead to neurotoxicity when not properly regulated. Excitotoxicity is a direct result of abnormal regulation of glutamate concentrations in the synapse, and is a common neurotoxic mediator associated with neurodegenerative disorders. It is well accepted that methamphetamine (METH), a potent central nervous stimulant with high abuse potential, and human immunodeficiency virus (HIV)-1 are implicated in the progression of neurocognitive malfunction. Both have been shown to induce common neurodegenerative effects such as astrogliosis, compromised blood brain barrier integrity, and excitotoxicity in the brain. Reduced glutamate uptake from neuronal synapses likely leads to the accumulation of glutamate in the extracellular spaces. Astrocytes express the glutamate transporters responsible for majority of the glutamate uptake from the synapse, as well as for vesicular glutamate release. However, the cellular and molecular mechanisms of astrocyte-mediated excitotoxicity in the context of METH and HIV-1 are undefined. Topics reviewed include dysregulation of the glutamate transporters, specifically excitatory amino acid transporter-2, metabotropic glutamate receptor(s) expression and the release of glutamate by vesicular exocytosis. We also discuss glutamate concentration dysregulation through astrocytic expression of enzymes for glutamate synthesis and metabolism. Lastly, we discuss recent evidence of various astrocyte and neuron crosstalk mechanisms implicated in glutamate regulation. Astrocytes play an essential role in the neuropathologies associated with METH/HIV-1-induced excitotoxicity. We hope to shed light on common cellular and molecular pathways astrocytes share in glutamate regulation during drug abuse and HIV-1 infection.
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Affiliation(s)
| | - Anuja Ghorpade
- University of North Texas Health Science Center, Fort Worth, TX, USA
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15
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Ferrucci A, Nonnemacher MR, Wigdahl B. Human immunodeficiency virus viral protein R as an extracellular protein in neuropathogenesis. Adv Virus Res 2012; 81:165-99. [PMID: 22094081 DOI: 10.1016/b978-0-12-385885-6.00010-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Numerous studies published in the past two decades have identified the viral protein R (Vpr) as one of the most versatile proteins in the life cycle of human immunodeficiency virus type 1 (HIV-1). In this regard, more than a thousand Vpr molecules are present in extracellular viral particles. Subsequent to viral entry, Vpr participates in early replicative events by assisting in viral genome nuclear import and, during the viral life cycle, by shuttling between the nucleus and the cytoplasm to accomplish its functions within the context of other replicative functions. Additionally, several studies have implicated Vpr as a proapoptotic protein because it promotes formation of permeability transition pores in mitochondria, which in turn affects transmembrane potential and adenosine triphosphate synthesis. Recent studies have identified Vpr as a virion-free protein in the serum and cerebrospinal fluid of patients infected with HIV-1 whose plasma viremia directly correlates with the extracellular concentration of Vpr. These observations pointed to a new role for Vpr as an additional weapon in the HIV-1 arsenal, involving the use of an extracellular protein to target and possibly inhibit HIV-1-uninfected bystander cells to enable them to escape immune surveillance. In addition, extracellular Vpr decreases adenosine triphosphate levels and affects the intracellular redox balance in neurons, ultimately causing their apoptosis. Herein, we review the role of Vpr as an extracellular protein and its downstream effects on cellular metabolism, functionality, and survival, with particular emphasis on how extracellular Vpr-induced oxidative stress might aggravate HIV-1-induced symptoms, thus affecting pathogenesis and disease progression.
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Affiliation(s)
- Adriano Ferrucci
- School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, Pennsylvania, USA
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16
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Glutaminase dysregulation in HIV-1-infected human microglia mediates neurotoxicity: relevant to HIV-1-associated neurocognitive disorders. J Neurosci 2011; 31:15195-204. [PMID: 22016553 DOI: 10.1523/jneurosci.2051-11.2011] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Microglia represent the main cellular targets of HIV-1 in the brain. Infected and/or activated microglia play a pathogenic role in HIV-associated neurocognitive disorders (HAND) by instigating primary dysfunction and subsequent death of neurons. Although microglia are known to secrete neurotoxins when infected with HIV-1, the detailed mechanism of neurotoxicity remains unclear. Using a human microglia primary culture system and macrophage-tropic HIV-1 strains, we have now demonstrated that HIV-1 infection of microglia resulted in a significant increase in extracellular glutamate concentrations and elevated levels of neurotoxicity. RNA and protein analysis revealed upregulation of the glutamate-generating enzyme glutaminase isoform glutaminase C in HIV-1-infected microglia. The clinical relevance of these findings was further corroborated with investigation of postmortem brain tissues. The glutaminase C levels in the brain tissues of HIV dementia individuals were significantly higher than HIV serum-negative control and correlated with elevated concentrations of glutamate. When glutaminase was subsequently inhibited by siRNA or by a small molecular inhibitor, the HIV-induced glutamate production and the neuronal loss was diminished. In conclusion, these findings support glutaminase as a potential component of the HAND pathogenic process as well as a novel therapeutic target in their treatment.
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17
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Genetic knockouts suggest a critical role for HIV co-receptors in models of HIV gp120-induced brain injury. J Neuroimmune Pharmacol 2011; 7:306-18. [PMID: 22124968 DOI: 10.1007/s11481-011-9328-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 11/16/2011] [Indexed: 02/06/2023]
Abstract
Infection with HIV-1 frequently affects the brain and causes NeuroAIDS prior to the development of overt AIDS. The HIV-1 envelope protein gp120 interacts with host CD4 and chemokine co-receptors to initiate infection of macrophages and lymphocytes. In addition, the virus or fragments of it, such as gp120, cause macrophages to produce neurotoxins and trigger neuronal injury and apoptosis. Moreover, the two major HIV co-receptors, the chemokine receptors CCR5 and CXCR4, serve numerous physiological functions and are widely expressed beyond immune cells, including cells in the brain. Therefore, HIV co-receptors are poised to play a direct and indirect part in the development of NeuroAIDS. Although rodents are not permissive to infection with wild type HIV-1, viral co-receptors - more than CD4 - are highly conserved between species, suggesting the animals can be suitable models for mechanistic studies addressing effects of receptor-ligand interaction other than infection. Of note, transgenic mice expressing HIV gp120 in the brain share several pathological hallmarks with NeuroAIDS brains. Against this background, we will discuss recently completed or initiated, ongoing studies that utilize HIV co-receptor knockout and viral gp120-transgenic mice as models for in vitro and in vivo experimentation in order to address the potential roles of HIV gp120 and its co-receptors in the development of NeuroAIDS.
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18
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Mitogen-activated protein kinase p38 in HIV infection and associated brain injury. J Neuroimmune Pharmacol 2011; 6:202-15. [PMID: 21286833 DOI: 10.1007/s11481-011-9260-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Accepted: 01/23/2011] [Indexed: 02/05/2023]
Abstract
Infection with human immunodeficiency virus-1 (HIV-1) often leads to HIV-associated neurocognitive disorders (HAND) prior to the progression to acquired immunodeficiency syndrome (AIDS). At the cellular level, mitogen-activated protein kinases (MAPK) provide a family of signal transducers that regulate many processes in response to extracellular stimuli and environmental stress, such as viral infection. Recently, evidence has accumulated suggesting that p38 MAPK plays crucial roles in various pathological processes associated with HIV infection, ranging from macrophage activation to neurotoxicity and impairment of neurogenesis to lymphocyte apoptosis. Thus, p38 MAPK, which has generally been linked to stress-related signal transduction, may be an important mediator in the development of AIDS and HAND.
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19
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Medders KE, Sejbuk NE, Maung R, Desai MK, Kaul M. Activation of p38 MAPK is required in monocytic and neuronal cells for HIV glycoprotein 120-induced neurotoxicity. THE JOURNAL OF IMMUNOLOGY 2010; 185:4883-95. [PMID: 20855878 DOI: 10.4049/jimmunol.0902535] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
HIV-1 envelope protein gp120 has been implicated in neurotoxin production by monocytic cells (i.e., macrophages and microglia), as well as in the pathogenesis of HIV-1-associated neurocognitive disorders. We previously showed in cerebrocortical cell cultures from rodents containing microglia, astrocytes, and neurons that overall inhibition of p38 MAPK signaling abrogated the neurotoxic effect of HIV-1 gp120. However, the time course of p38 MAPK activation and the contribution of this kinase in the various cell types remained unknown. In this study, we found that active p38 MAPK is required in monocytic lineage cells (i.e., macrophages and microglia) and neuronal cells for HIV gp120-induced neurotoxicity to occur. In cerebrocortical cell cultures, HIV-1 gp120 stimulated a time-dependent overall increase in active p38 MAPK, and the activated kinase was primarily detected in microglia and neurons. Interestingly, increased activation of p38 MAPK and neuronal death in response to gp120 were prevented by prior depletion of microglia or the presence of CCR5 ligand CCL4 or p38 MAPK inhibitors. In human monocytic THP-1 cells and primary monocyte-derived macrophages, HIV gp120-stimulated production of neurotoxins was abrogated by prior introduction into the cells of a dominant-negative p38 MAPK mutant or p38 MAPK small interfering RNA. In addition, the neurotoxic effects of cell-free supernatants from gp120-stimulated monocytic THP-1 cells were prevented in microglia-depleted cerebrocortical cells pretreated with a pharmacological inhibitor of p38 MAPK. Thus, p38 MAPK signaling was critical, upon exposure to HIV gp120, for the neurotoxic phenotype of monocytic cells and subsequent toxin-initiated neuronal apoptosis.
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Affiliation(s)
- Kathryn E Medders
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
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20
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Davies NW, Guillemin G, Brew BJ. Tryptophan, Neurodegeneration and HIV-Associated Neurocognitive Disorder. Int J Tryptophan Res 2010; 3:121-40. [PMID: 22084594 PMCID: PMC3195234 DOI: 10.4137/ijtr.s4321] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
This review presents an up-to-date assessment of the role of the tryptophan metabolic and catabolic pathways in neurodegenerative disease and HIV-associated neurocognitive disorder. The kynurenine pathway and the effects of each of its enzymes and products are reviewed. The differential expression of the kynurenine pathway in cells within the brain, including inflammatory cells, is explored given the increasing recognition of the importance of inflammation in neurodegenerative disease. An overview of common mechanisms of neurodegeneration is presented before a review and discussion of the evidence for a pathogenetic role of the kynurenine pathway in Alzheimer's disease, HIV-associated neurocognitive disorder, Huntington's disease, motor neurone disease, and Parkinson's disease.
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Affiliation(s)
- Nicholas W.S. Davies
- Department of Neurology, and
- St Vincent’s Centre for Applied Medical Research, St Vincent’s Hospital, Darlinghurst, Sydney, Australia
| | - Gilles Guillemin
- St Vincent’s Centre for Applied Medical Research, St Vincent’s Hospital, Darlinghurst, Sydney, Australia
| | - Bruce J. Brew
- Department of Neurology, and
- St Vincent’s Centre for Applied Medical Research, St Vincent’s Hospital, Darlinghurst, Sydney, Australia
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21
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Kilareski EM, Shah S, Nonnemacher MR, Wigdahl B. Regulation of HIV-1 transcription in cells of the monocyte-macrophage lineage. Retrovirology 2009; 6:118. [PMID: 20030845 PMCID: PMC2805609 DOI: 10.1186/1742-4690-6-118] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Accepted: 12/23/2009] [Indexed: 12/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) has been shown to replicate productively in cells of the monocyte-macrophage lineage, although replication occurs to a lesser extent than in infected T cells. As cells of the monocyte-macrophage lineage become differentiated and activated and subsequently travel to a variety of end organs, they become a source of infectious virus and secreted viral proteins and cellular products that likely initiate pathological consequences in a number of organ systems. During this process, alterations in a number of signaling pathways, including the level and functional properties of many cellular transcription factors, alter the course of HIV-1 long terminal repeat (LTR)-directed gene expression. This process ultimately results in events that contribute to the pathogenesis of HIV-1 infection. First, increased transcription leads to the upregulation of infectious virus production, and the increased production of viral proteins (gp120, Tat, Nef, and Vpr), which have additional activities as extracellular proteins. Increased viral production and the presence of toxic proteins lead to enhanced deregulation of cellular functions increasing the production of toxic cellular proteins and metabolites and the resulting organ-specific pathologic consequences such as neuroAIDS. This article reviews the structural and functional features of the cis-acting elements upstream and downstream of the transcriptional start site in the retroviral LTR. It also includes a discussion of the regulation of the retroviral LTR in the monocyte-macrophage lineage during virus infection of the bone marrow, the peripheral blood, the lymphoid tissues, and end organs such as the brain. The impact of genetic variation on LTR-directed transcription during the course of retrovirus disease is also reviewed.
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Affiliation(s)
- Evelyn M Kilareski
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Center for Molecular Therapeutics and Resistance, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
| | - Sonia Shah
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Center for Molecular Therapeutics and Resistance, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
| | - Michael R Nonnemacher
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Center for Molecular Therapeutics and Resistance, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
| | - Brian Wigdahl
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Center for Molecular Therapeutics and Resistance, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N 15th St, Philadelphia, Pennsylvania 19102, USA
- Department of Microbiology and Immunology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA
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22
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Reiner BC, Keblesh JP, Xiong H. Methamphetamine abuse, HIV infection, and neurotoxicity. INTERNATIONAL JOURNAL OF PHYSIOLOGY, PATHOPHYSIOLOGY AND PHARMACOLOGY 2009; 1:162-179. [PMID: 20411028 PMCID: PMC2856939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Accepted: 09/21/2009] [Indexed: 05/29/2023]
Abstract
Methamphetamine (Meth) use and human immunodeficiency virus (HIV) infection are major public health problems in the world today. Ample evidence indicates that HIV transfection risk is greatly enhanced with Meth use. Studies have shown that both HIV infection and Meth abuse can cause neuronal injury leading to neurodegeneration. While many studies have focused on the individual effects of Meth and HIV on the brain, few investigations have been carried out on their co-morbid effect in the nervous system. In this review, we try to summarize recent progress on individual effects of Meth and HIV on neurodegeneration and their potential underlying mechanisms, in addition to exploring their co-morbid effect on the brain.
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Affiliation(s)
- Benjamin C Reiner
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
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23
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Erdmann N, Tian C, Huang Y, Zhao J, Herek S, Curthoys N, Zheng J. In vitro glutaminase regulation and mechanisms of glutamate generation in HIV-1-infected macrophage. J Neurochem 2009; 109:551-61. [PMID: 19222703 DOI: 10.1111/j.1471-4159.2009.05989.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mononuclear phagocyte (MP, macrophages and microglia) dysfunction plays a significant role in the pathogenesis of HIV-1-associated dementia (HAD) through the production and release of soluble neurotoxic factors including glutamate. Glutamate production is greatly increased following HIV-1 infection of cultured MP, a process dependent upon the glutamate-generating enzyme glutaminase. Glutaminase inhibition was previously found to significantly decrease macrophage-mediated neurotoxicity. Potential mechanisms of glutaminase-mediated excitotoxicity including enzyme up-regulation, increased enzyme activity and glutaminase localization were investigated in this report. RNA and protein analysis of HIV-infected human primary macrophage revealed up-regulation of the glutaminase isoform GAC, yet identified no changes in the kidney-type glutaminase isoform over the course of infection. Glutaminase is a mitochondrial protein, but was found to be released into the cytosol and extracellular space following infection. This released enzyme is capable of rapidly converting the abundant extracellular amino acid glutamine into excitotoxic levels of glutamate in an energetically favorable process. These findings support glutaminase as a potential component of the HAD pathogenic process and identify a possible therapeutic avenue for the treatment of neuroinflammatory states such as HAD.
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Affiliation(s)
- Nathan Erdmann
- Laboratory of Neurotoxicology at the Center for Neurovirology and Neurodegenerative Disorders, Omaha, Nebraska 68198-5880, USA
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24
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Xing HQ, Hayakawa H, Izumo K, Kubota R, Gelpi E, Budka H, Izumo S. In vivo expression of proinflammatory cytokines in HIV encephalitis: an analysis of 11 autopsy cases. Neuropathology 2009; 29:433-42. [PMID: 19170891 DOI: 10.1111/j.1440-1789.2008.00996.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
As the pathogenesis of AIDS dementia complex (ADC), cytokines such as TNF-alpha and IL-1beta have been thought to have toxic effects on CNS cells and induce neuronal cell death. However, many of the discussions have been based on the studies done by in vitro experiments. There are only a few reports which demonstrate proinflammatory cytokines directly in vivo in HIV encephalitis (HIVE) brains, and roles of these cytokines with relation to HIV-1 infection are not yet clarified. In the present study, we examined 11 autopsy cases of HIVE using immunohistochemistry, and explored which cell types expressed these cytokines and whether expression of cytokines was related to viral infection. IL-1beta was detected in the frontal white matter of all 11 cases where microglial nodules were observed to varying degrees, whereas TNF-alpha was detected in seven cases. IL-1beta- or TNF-alpha-positive cells were almost restricted to CD68-positive macrophages/microglia and mild expression of these cytokines by astrocytes was observed in two cases with severe HIVE. IL-1beta was detected in some HIVp24-positive multinucleated giant cells. However, we could not detect TNF-alpha expression in the HIVp24-positive cells, which indicates that IL-1beta is induced by HIV-1 infection. In conclusion, a macrophage/microglia lineage is the main cell type to release cytokines in HIVE, and IL-1beta expression by HIV-1-infected cells may be one of the important factors for induction of HIVE. In addition, many non-infected macrophages/microglia as well as some astrocytes express IL-1beta and TNF-alpha, which might contribute to pathogenesis of ADC.
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Affiliation(s)
- Hui Qin Xing
- Division of Molecular Pathology, Center for Chronic Viral Diseases, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, Kagoshima, Japan.
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25
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Ronaldson PT, Persidsky Y, Bendayan R. Regulation of ABC membrane transporters in glial cells: Relevance to the pharmacotherapy of brain HIV-1 infection. Glia 2008; 56:1711-35. [DOI: 10.1002/glia.20725] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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26
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Cadet JL, Krasnova IN. Interactions of HIV and methamphetamine: cellular and molecular mechanisms of toxicity potentiation. Neurotox Res 2008; 12:181-204. [PMID: 17967742 DOI: 10.1007/bf03033915] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Methamphetamine (METH) is a highly addictive psychostimulant drug, whose abuse has reached epidemic proportions worldwide. METH use is disproportionally represented among populations at high risks for developing HIV infection or who are already infected with the virus. Psychostimulant abuse has been reported to exacerbate the cognitive deficits and neurodegenerative abnormalities observed in HIV-positive patients. Thus, the purpose of the present paper is to review the clinical and basic observations that METH potentiates the adverse effects of HIV infection. An additional purpose is to provide a synthesis of the cellular and molecular mechanisms that might be responsible for the increased toxicity observed in co-morbid patients. The reviewed data indicate that METH and HIV proteins, including gp120, gp41, Tat, Vpr and Nef, converge on various caspase-dependent death pathways to cause neuronal apoptosis. The role of reactive microgliosis in METH- and in HIV-induced toxicity is also discussed.
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Affiliation(s)
- J L Cadet
- Molecular Neuropsychiatry Branch, NIH/NIDA Intramural Research Program, Baltimore, MD 21224, USA.
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27
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Kazmierczak K, Potash MJ. Host and virus strain dependence in activation of human macrophages by human immunodeficiency virus type 1. J Neurovirol 2008; 13:452-61. [PMID: 17994430 DOI: 10.1080/13550280701510104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1)-associated neuropathogenesis occurs in a large minority of infected people. Presently, there are neither viral nor cellular markers that predict the development of brain disease during HIV-1 infection. This study was conducted to determine whether there exist systematic differences among human cell donors and virus strains for the activation of macrophage gene expression by HIV-1 that may contribute to neuropathogenesis. Four HIV-1, ADA and B-aL, which were isolated from peripheral tissues of acquired immunodeficiency syndrome (AIDS) patients, and DJV and YU-2, which were isolated from brains of patients with HIV-1-associated dementia, were compared for induction of expression of cellular genes associated with antiviral activity or inflammation in monocyte-derived macrophages from several donors. Virus replication and cytokine production were scored by enzyme-linked immunosorbent assay (ELISA) and cellular transcripts were measured by real-time polymerase chain reaction (PCR). ADA and B-aL productively infected cells from all donors tested and induced all cellular transcripts tested, illustrating a common response of macrophages to HIV-1 replication. In sharp contrast, the viruses associated with neuropathogenesis, DJV and YU-2, induced intense gene expression early after infection in cells from a subset of donors but DJV did not productively infect these cells. No such heterogeneity was observed in the responses of macrophages during high-level replication of any HIV-1 tested. The susceptibility to early activation by HIV-1 may reflect susceptibility to neuropathogenesis in AIDS.
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Affiliation(s)
- Katarzyna Kazmierczak
- Molecular Virology Division, St. Luke's-Roosevelt Hospital Center, Columbia University Medical Center, 432 West 58th Street, New York, NY 10019, USA
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28
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Kaul M. HIV's double strike at the brain: neuronal toxicity and compromised neurogenesis. FRONT BIOSCI-LANDMRK 2008; 13:2484-94. [PMID: 17981728 DOI: 10.2741/2860] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Infection with the human immunodeficiency virus-1 (HIV-1) and acquired immunodeficiency syndrome (AIDS) are often associated with severe and debilitating neurological problems that include behavioral abnormalities, motor dysfunction and frank dementia. HIV-1-infected peripheral immune cells, in particular macrophages, appear to infiltrate the CNS, release neurotoxins and provoke a neuropathological response involving all cell types in the brain. In the CNS, HIV-1 and its components initiate activation of chemokine receptors, inflammatory mediators and glutamate receptor-mediated excitotoxicity, all of which can activate numerous downstream signaling pathways and disturb neuronal and glial function. Recent experimental evidence suggests that disturbance by HIV-1 results not only in neuronal injury and death but also in impairment of neurogenesis. This article will review recently identified pathological mechanisms which potentially contribute to the development of neurocognitive impairment and dementia in association with HIV-1 infection.
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Affiliation(s)
- Marcus Kaul
- Infectious and Inflammatory Disease Center, Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
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29
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Mechanisms of neuroimmunity and neurodegeneration associated with HIV-1 infection and AIDS. J Neuroimmune Pharmacol 2007; 1:138-51. [PMID: 18040780 DOI: 10.1007/s11481-006-9011-9] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Infection with the human immunodeficiency virus-1 (HIV-1) and acquired immunodeficiency syndrome (AIDS) are a persistent health problem worldwide. HIV-1 seems to enter the brain very soon after peripheral infection and can induce severe and debilitating neurological problems that include behavioral abnormalities, motor dysfunction, and frank dementia. Infected peripheral immune-competent cells, in particular macrophages, appear to infiltrate the CNS and provoke a neuropathological response involving all cell types in the brain. The course of HIV-1 disease is strongly influenced by viral and host factors, such as the viral strain and the response of the host's immune system. In addition, HIV-1-dependent disease processes in the periphery have a substantial effect on the pathological changes in the central nervous system (CNS), although the brain eventually harbors a distinctive viral population of its own. In the CNS, HIV-1 also incites activation of chemokine receptors, inflammatory mediators, extracellular matrix-degrading enzymes, and glutamate receptor-mediated excitotoxicity, all of which can initiate numerous downstream signaling pathways and disturb neuronal and glial function. Although there have been many major improvements in the control of viral infection in the periphery, an effective therapy for HIV-1-associated dementia (HAD) is still not available. This article addresses recently uncovered pathologic neuroimmune and degenerative mechanisms contributing to neuronal damage induced by HIV-1 and discusses experimental and potentially future therapeutic approaches.
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30
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Stone TW, Forrest CM, Mackay GM, Stoy N, Darlington LG. Tryptophan, adenosine, neurodegeneration and neuroprotection. Metab Brain Dis 2007; 22:337-52. [PMID: 17712616 DOI: 10.1007/s11011-007-9064-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This review summarises the potential contributions of two groups of compounds to cerebral dysfunction and damage in metabolic disease. The kynurenines are oxidised metabolites of tryptophan, the kynurenine pathway being the major route for tryptophan catabolism in most tissues. The pathway includes quinolinic acid -- an agonist at N-methyl-D-aspartate (NMDA) receptors, kynurenic acid -- an antagonist at glutamate and nicotinic receptors, and other redox active compounds that are able to generate free radicals under many physiological and pathological conditions. The pathway is activated in immune-competent cells, including glia in the central nervous system, and may contribute substantially to delayed neuronal damage following an infarct or metabolic insult. Adenosine is an ubiquitous purine that can protect neurons by suppressing excitatory neurotransmitter release, reducing calcium fluxes and inhibiting NMDA receptors. The extent of brain injury is critically dependent on the balance between the two opposing forces of kynurenines and purines.
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Affiliation(s)
- T W Stone
- Institute of Biomedical & Life Sciences, West Medical Building, University of Glasgow, Glasgow, Scotland, UK.
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31
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32
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Jayadev S, Yun B, Nguyen H, Yokoo H, Morrison RS, Garden GA. The glial response to CNS HIV infection includes p53 activation and increased expression of p53 target genes. J Neuroimmune Pharmacol 2007; 2:359-70. [PMID: 18040854 DOI: 10.1007/s11481-007-9095-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Accepted: 09/26/2007] [Indexed: 01/02/2023]
Abstract
HIV-associated dementia (HAD) is a chronic neuroinflammatory disease that remains an important clinical problem without available rational treatment. As HIV does not infect neurons, the pathogenesis of HAD is thought to be secondary to the impact of infected leukocytes, including parenchymal microglia, which can secrete inflammatory mediators and viral products that alter the function of surrounding uninfected cells. We previously reported that the transcription factor p53 accumulates in neurons, microglia, and astrocytes of HAD patients. We have also shown that microglia from p53-deficient mice fail to induce neurotoxicity in response to the HIV coat protein gp120 in a coculture system, supporting the hypothesis that p53 plays a pathogenic role in the chronic neuroinflammatory component of HIV-associated neurodegeneration. We analyzed the extent and cell type specificity of p53 accumulation in subcortical white matter of ten AIDS patients that had previously been shown to demonstrate white matter p53 accumulation. To determine if p53 activation functioned to alter gene expression in HAD, cortical tissue sections were also immunolabeled for the p53 target genes Bax and p21(WAF1). These studies reveal that microglia, astrocytes, and oligodendrocytes all demonstrate p53 activation in response to HIV infection. We observed immunoreactivity for both Bax and p21(WAF1) in neurons and glia from patients demonstrating elevated p53 immunoreactivity. Our findings demonstrate that widespread increased p53 expression is present in HAD. Activation of p53 mediated pathways in the glia of HAD patients may contribute to the neuroinflammatory processes that promote neurodegeneration by inhibiting glial proliferation and/or promoting glial cell dysfunction.
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Affiliation(s)
- Suman Jayadev
- Department of Neurology, University of Washington, Seattle, WA, USA
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Erdmann N, Zhao J, Lopez AL, Herek S, Curthoys N, Hexum TD, Tsukamoto T, Ferraris D, Zheng J. Glutamate production by HIV-1 infected human macrophage is blocked by the inhibition of glutaminase. J Neurochem 2007; 102:539-49. [PMID: 17596215 PMCID: PMC1976281 DOI: 10.1111/j.1471-4159.2007.04594.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mononuclear phagocyte (macrophages and microglia) dysfunction plays a significant role in the pathogenesis of human immunodeficiency virus (HIV) associated dementia (HAD) through the production and release of soluble neurotoxic factors including glutamate. The mechanism of glutamate regulation by HIV-1 infection remains unclear. In this report, we investigated whether the enzyme glutaminase is responsible for glutamate generation by HIV-1 infected monocyte-derived macrophages. We tested the functionality of novel small molecule inhibitors designed to specifically block the activity of glutaminase. Glutaminase inhibitors were first characterized in a kinetic assay with crude glutaminase from rat brain revealing an uncompetitive mechanism of inhibition. The inhibitors were then tested in vitro for their ability to prevent glutamate generation by HIV-infected macrophages, their effect upon macrophage viability, and HIV infection. To validate these findings, glutaminase specific siRNA was tested for its ability to prevent glutamate increase during infection. Our results show that both glutaminase specific small molecule inhibitors and glutaminase specific siRNA were effective at preventing increases in glutamate by HIV-1 infected macrophage. These findings support glutaminase as a potential component of the HAD pathogenic process and identify a possible therapeutic avenue for the treatment of neuroinflammatory states such as HAD.
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Affiliation(s)
- Nathan Erdmann
- Laboratory of Neurotoxicology at the Center for Neurovirology and Neurodegenerative Disorders, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Pharmacology/Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Jianxing Zhao
- Laboratory of Neurotoxicology at the Center for Neurovirology and Neurodegenerative Disorders, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Pharmacology/Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Alicia L. Lopez
- Laboratory of Neurotoxicology at the Center for Neurovirology and Neurodegenerative Disorders, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Pharmacology/Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Shelley Herek
- Laboratory of Neurotoxicology at the Center for Neurovirology and Neurodegenerative Disorders, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Pharmacology/Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Norman Curthoys
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Terry D. Hexum
- Department of Pharmacology/Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | | | | | - Jialin Zheng
- Laboratory of Neurotoxicology at the Center for Neurovirology and Neurodegenerative Disorders, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Pharmacology/Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Pathology/Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Yano M, Nakamuta S, Shiota M, Endo H, Kido H. Gatekeeper role of 14-3-3tau protein in HIV-1 gp120-mediated apoptosis of human endothelial cells by inactivation of Bad. AIDS 2007; 21:911-20. [PMID: 17457084 DOI: 10.1097/qad.0b013e32810539f3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE HIV-1-associated dementia (HAD) is a major neurological complication often observed in the advanced stages of AIDS. We have reported that 14-3-3 proteins in cerebrospinal fluid, reflecting neuronal cell destruction, is a real-time marker of HAD progression. This study was designed to examine the role of 14-3-3 proteins in HAD. DESIGN An in-vitro human umbilical vein endothelial cells (HUVEC) model of gp120 protein-induced apoptosis to study the protective role of 14-3-3 in HIV-1 gp120/CXCR4-mediated cell death. METHODS The alpha-chemokine receptor-mediated cell death by HIV-1 envelope protein, gp120, the critical event that causes neuron loss and endothelial cell injury, was evaluated in HUVEC undergoing gp120-induced apoptosis through the CXCR4 receptor. We studied the effects of siRNA for each 14-3-3 isoform on the death of HUVEC treated with CXCR4-preferring gp120 (IIIB). RESULTS Gp120 increased the expression of 14-3-3tau in HUVEC. The binding of Gp120 to CXCR4 induced apoptosis of HUVEC through decreased binding of 14-3-3tau to the pro-apoptotic molecule, Bad. Treatment of the cells with dsRNA against 14-3-3tau enhanced the gp120-mediated dephosphorylation of Bad and its association with Bcl-XL in mitochondria, accelerating the gp120-induced apoptosis, whereas suppression of Bad by RNAi rescued the cells from apoptosis triggered by gp120. CONCLUSIONS The specific up-regulation of 14-3-3tau in HUVEC negatively regulated gp120/CXCR4-mediated cell death by protecting Bad dephosphorylation.
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Affiliation(s)
- Mihiro Yano
- Division of Enzyme Chemistry, Institute for Enzyme Research, The University of Tokushima, Tokushima 770-8503, Japan
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Erdmann NB, Whitney NP, Zheng J. Potentiation of Excitotoxicity in HIV-1 Associated Dementia and the Significance of Glutaminase. ACTA ACUST UNITED AC 2006; 6:315-328. [PMID: 18059978 DOI: 10.1016/j.cnr.2006.09.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
HIV-1 Associated Dementia (HAD) is a significant consequence of HIV infection. Although multiple inflammatory factors contribute to this chronic, progressive dementia, excitotoxic damage appears to be an underlying mechanism in the neurodegenerative process. Excitotoxicity is a cumulative effect of multiple processes occurring in the CNS during HAD. The overstimulation of glutamate receptors, an increased vulnerability of neurons, and disrupted astrocyte support each potentiate excitotoxic damage to neurons. Recent evidence suggests that poorly controlled generation of glutamate by phosphate-activated glutaminase may contribute to the neurotoxic state typical of HAD as well as other neurodegenerative disorders. Glutaminase converts glutamine, a widely available substrate throughout the CNS to glutamate. Inflammatory conditions may precipitate unregulated activity of glutaminase, a potentially important mechanism in HAD pathogenesis.
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Affiliation(s)
- Nathan B Erdmann
- The laboratory of Neurotoxicology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5880
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Saavedra-Lozano J, Ramos JT, Sanz F, Navarro ML, de José MI, Martín-Fontelos P, Mellado MJ, Leal JAL, Rodriguez C, Luque I, Madison SJ, Irlbeck D, Lanier ER, Ramilo O. Salvage therapy with abacavir and other reverse transcriptase inhibitors for human immunodeficiency-associated encephalopathy. Pediatr Infect Dis J 2006; 25:1142-52. [PMID: 17133160 DOI: 10.1097/01.inf.0000246976.40494.af] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND HIV-associated encephalopathy (HIV-AE) is a severe neurologic condition that affects HIV-infected children. The potential benefit of antiretroviral (ARV) agents with good cerebrospinal fluid (CSF) penetration remains to be defined. Abacavir (ABC) achieves good CSF concentrations and studies of high-dose ABC showed benefit in adults with HIV dementia. The present study evaluated the safety and virologic, immunologic and neuropsychological responses of an ARV regimen including high-dose ABC in children with HIV-AE. METHODS Children between 3 months and 18 years old and abacavir-naive with HIV-AE and virologic failure were eligible. RESULTS : Seventeen children (16 ARV-experienced) were enrolled and 14 children completed 48 weeks of therapy. The overall tolerability was good; 2 children had a possible hypersensitivity reaction. At week 48, 53% and 59% of the children achieved HIV RNA levels below the limit of quantitation in plasma and CSF, respectively. The median (25%-75% range) change of HIV RNA from baseline to week 48 was -2.29 (-0.81 to -2.47) log10 copies/mL in plasma and -0.94 (0 to -1.13) log10 copies/mL in CSF. The mean increases in CD4 (+/-standard error of mean) cell count and CD4% were 427 (+/-169) cells/mm and 8% (+/-2), respectively. Concentrations of soluble tumor necrosis factor receptor II were reduced in plasma and CSF. Children less than 6 years of age demonstrated significant neuropsychological improvement at week 48. CONCLUSIONS In the present study with a limited number of children, highly active ARV therapy including high-dose ABC showed a safety profile similar to standard dose ABC and provided clinical, immunologic and virologic response in children with HIV-AE at week 48. Children less than 6 years of age also demonstrated significant neuropsychological improvement.
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Viviani B, Gardoni F, Bartesaghi S, Corsini E, Facchi A, Galli CL, Di Luca M, Marinovich M. Interleukin-1β Released by gp120 Drives Neural Death through Tyrosine Phosphorylation and Trafficking of NMDA Receptors. J Biol Chem 2006; 281:30212-22. [PMID: 16887807 DOI: 10.1074/jbc.m602156200] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Interleukin-1beta is a proinflammatory cytokine implicated under pathological conditions involving NMDA receptor activation, including the AIDS dementia complex (HAD). No information is available on the molecular mechanisms recruited by native interleukin-1beta produced under this type of condition. Using a sandwich co-culture of primary hippocampal neurons and glia, we investigated whether native interleukin-1beta released by HIV-gp120-activated glia (i) affects NMDAR functions and (ii) the relevance on neuronal spine density and survival, two specific traits of HAD. Increased phosphorylation of NR2B Tyr-1472 was observed after 24 h of exposure of neurons to 600 pm gp120. This effect occurred only when neurons were treated in the presence of glial cells and was abolished by the interleukin-1 receptor antagonist (IL-1ra). Gp120-induced phosphorylation of NR2B resulted in a sustained elevation of intracellular Ca(2+) in neurons and in a significant increase of NR2B binding to PSD95. Increased intracellular Ca(2+) was prevented by 10 mum ifenprodil, that selectively inhibits receptors containing the NR2B, by interleukin-1ra and by Ca-pYEEIE, a Src family SH2 inhibitor peptide. These last two inhibitors, prevented also NR2B binding to PSD95. Finally, gp120 reduced by 35% of the total PSD95 positive spine density after 48 h of treatment and induced by 30% of the neuronal death. Again, both of these effects were blocked by Ca-pYEEIE. Altogether, our data show that gp120 releasing interleukin-1beta from glia increases tyrosine phosphorylation of NMDAR. Thus, tyrosine phosphorylation may contribute to the sensitization of the receptor increasing its function and synaptic localization. Both of these effects are relevant for neurodegeneration.
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Affiliation(s)
- Barbara Viviani
- Laboratory of Toxicology and Center of Excellence on Neurodegenerative Diseases, Department of Pharmacological Sciences, University of Milan, 20133 Milan, Italy
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Berman NE, Sheffield LG, Purcell J, Joag SV, Narayan O, Cheney P. Gradient of microglial activation in the brain of SIV infected macaques. ACTA ACUST UNITED AC 2006; 2:43-54. [PMID: 16873184 DOI: 10.1300/j128v02n01_03] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Brains of macaques inoculated with macrophage-tropic, neurovirulent virus 7F, with lymphocyte-tropic SIV mac239, or with dual-tropic SIVmac239/1yE, were examined for microglial activation, astrocyte activation, apoptosis and neuron loss. The brain one animal inoculated with neurovirulent virus 7f showed massive microglial activation as assessed by expression of the major histo-compatibility complex class II (MHC-II). In this animal very numerous, large microglial nodules expressing MHC-II were concentrated in the basal pons and internal capsule. These microglial nodules contained cells undergoing apoptosis detected by in situ end labeling of fragmented DNA. In this animal, neuron loss was apparent near the microglial nodules. In the animals inoculated with SIVmac239 or SIVmac239/17E, pathologic changes such as perivascular cuffing and formation of microglial nodules were absent. However, increased expression of MHC-11 by microglial cells was also concentrated in white matter of the basal pons, midbrain and internal capsule. These results indicate the microglial activation in SIV-infected macaques follows a ventral to dorsal gradient regardless of viral tropism. These results also show that the type and severity of neuropathological changes in SIV-infected macaques is highly dependent on the tropism of the inoculated virus.
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Affiliation(s)
- N E Berman
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Room 2000 WHE, Kansas City, KS 66160-7400, USA.
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Everall IP, Barnes H. Reduction in phosphorylated heavy neurofilament in the cerebellum in HIV disease. ACTA ACUST UNITED AC 2006; 2:43-55. [PMID: 16873193 DOI: 10.1300/j128v02n02_05] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In the absence of significant neuronal infection HIV induces neuronal damage and death. The pathogenesis of this process is not clear and can only be assessed in the HIV infected brain by examining surviving neuronal populations. Cerebellar Purkinje cells are a model population. We have already demonstrated glutamate receptor alterations in these neurons in AIDS, and in the current study we have investigated the phosphorylation status of heavy neurofilament (NF-H), which is under the control of various intracellular kinases. While the number of Purkinje cells expressing non-phosphorylated NF-H was unchanged, the number of Purkinje cells expressing phosphorylated NF-H was decreased by 36% in the HIV group. This may be a marker of neuronal damage, and possibly indicate alteration in the activity of various intracellular signalling kinase pathways in the HIV infected brain.
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Affiliation(s)
- I P Everall
- Department of Neuropathology, Institute of Psychiatry, London, United Kingdom
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Kaul M, Ma Q, Medders KE, Desai MK, Lipton SA. HIV-1 coreceptors CCR5 and CXCR4 both mediate neuronal cell death but CCR5 paradoxically can also contribute to protection. Cell Death Differ 2006; 14:296-305. [PMID: 16841089 DOI: 10.1038/sj.cdd.4402006] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The chemokine receptors CCR5 and CXCR4 serve, in addition to CD4, as coreceptors for human immunodeficiency virus-1 (HIV-1), and infection with HIV-1 can cause dementia. In brain-derived cells, HIV-1 envelope glycoprotein gp120 initiates a signaling cascade that involves p38 mitogen-activated protein kinase and leads to neuronal cell death. Using mixed neuronal/glial cultures from rats and mice genetically deficient in one or both HIV coreceptors, we show here that CCR5, CXCR4 or both can mediate HIV/gp120 neurotoxicity depending on the viral strain. Paradoxically, we also found evidence for a CCR5-mediated neuroprotective pathway. We identify protein kinase Akt/PKB as an essential component of this pathway, which can be triggered by the CCR5 agonists macrophage inflammatory protein-1beta and regulated-and-normal-T-cell-expressed-and-secreted. Moreover, these CCR5 ligands prevent neuronal cell death induced by stromal cell-derived factor-1, a CXCR4 agonist. Both neurons and glia coexpress CXCR4 and CCR5. Ca2+ imaging experiments demonstrate that engagement of CCR5 prevents CXCR4-triggered increases in intracellular free Ca2+. This finding suggests that CCR5 ligands can protect neurons at least, in part, by modulating CXCR4-mediated toxicity through heterologous desensitization.
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Affiliation(s)
- M Kaul
- Center for Neuroscience and Aging, Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Kaul M, Zheng J, Okamoto S, Gendelman HE, Lipton SA. HIV-1 infection and AIDS: consequences for the central nervous system. Cell Death Differ 2006; 12 Suppl 1:878-92. [PMID: 15832177 DOI: 10.1038/sj.cdd.4401623] [Citation(s) in RCA: 265] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Infection with the human immunodeficiency virus-1 (HIV-1) can induce severe and debilitating neurological problems that include behavioral abnormalities, motor dysfunction and frank dementia. After infiltrating peripheral immune competent cells, in particular macrophages, HIV-1 provokes a neuropathological response involving all cell types in the brain. HIV-1 also incites activation of chemokine receptors, inflammatory mediators, extracellular matrix-degrading enzymes and glutamate receptor-mediated excitotoxicity, all of which can trigger numerous downstream signaling pathways and disrupt neuronal and glial function. This review will discuss recently uncovered pathologic neuroimmune and degenerative mechanisms contributing to neuronal damage induced by HIV-1 and potential approaches for development of future therapeutic intervention.
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Affiliation(s)
- M Kaul
- Center for Neuroscience and Aging Research, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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42
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McCrossan M, Marsden M, Carnie FW, Minnis S, Hansoti B, Anthony IC, Brettle RP, Bell JE, Simmonds P. An immune control model for viral replication in the CNS during presymptomatic HIV infection. ACTA ACUST UNITED AC 2005; 129:503-16. [PMID: 16317019 DOI: 10.1093/brain/awh695] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The brain is targeted by human immunodeficiency virus type 1 (HIV-1) during the course of untreated infection, leading to cognitive impairment, neurological damage and HIV encephalitis (HIVE). To study early dynamics of HIV entry into the brain, we examined a unique autopsy series of samples obtained from 15 untreated individuals who died in the presymptomatic stages of infection from non-HIV causes. HIV was detected and quantified by limiting dilution PCR and genetically characterized in the V3 region of env. Limiting dilution was shown to be essential for correct estimation of genetic partitioning between brain- and lymphoid-associated HIV populations. While no actively expressing HIV-infected cells were detected by immunohistochemistry, variable and generally extremely low levels of proviral DNA were detected in presymptomatic brain samples. V3 region sequences were frequently genetically distinct from lymphoid-associated HIV variants, with association index (AI) values similar to those observed in cases of HIVE. Infiltration of CD8 lymphocytes in the brain was strongly associated with expression of activation markers (MHCII; R = 0.619; P < 0.05), the presence of HIV-infected cells (proviral load; R = 0.608; P < 0.05) and genetic segregation of brain variants from populations in lymphoid tissue (AI value, R = -0.528; P approximately 0.05). CD8 lymphocytes may thus limit replication of HIV seeded into the brain in early stages of infection. Neurological complications in AIDS occur when this control breaks down, due to systemic immunosuppression from HIV that destroys CD8 lymphocyte function and/or through the evolution of more aggressive neuropathogenic variants.
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Affiliation(s)
- M McCrossan
- Centre for Infectious Diseases, Western General Hospital, Edinburgh, UK
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43
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Abstract
Since identification of the human immunodeficiency virus-1 (HIV-1), numerous studies suggest a link between neurological impairments, in particular dementia, with acquired immunodeficiency syndrome (AIDS) with alarming occurrence worldwide. Approximately, 60% of HIV-infected people show some form of neurological impairment, and neuropathological changes are found in 90% of autopsied cases. Approximately 30% of untreated HIV-infected persons may develop dementia. The mechanisms behind these pathological changes are still not understood. Mounting data obtained by in vivo and in vitro experiments suggest that neuronal apoptosis is a major feature of HIV associated dementia (HAD), which can occur in the absence of direct infection of neurons. The major pathway of neuronal apoptosis occurs indirectly through release of neurotoxins by activated cells in the central nervous system (CNS) involving the induction of excitotoxicity and oxidative stress. In addition a direct mechanism induced by viral proteins in the pathogenesis of HAD may also play a role. This review focuses on the molecular mechanisms of HIV-associated dementia and possible therapeutic strategies.
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Affiliation(s)
- Hakan Ozdener
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA.
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Abstract
In the past decade we have seen a milder phenotype and decreased incidence of HIV-1 associated dementia (HAD), largely due to the widespread use of combination chemotherapy to reduce viral burden. However, the prevalence of neurologic disease in people living with HIV-1 has actually increased, raising significant concerns that new therapeutic strategies, directed at restoring neuronal and glial homeostasis and signaling in the central nervous system (CNS), as opposed to directly interfering with the life cycle of HIV-1, must be developed. In this review, we focus briefly on previous Phase 1 clinical trials for adjunctive (i.e., chemotherapeutic agents that do not have a primary antiretroviral mechanism of action) therapy in patients with HAD, followed by an overview of key molecular events in the neuropathogenesis of HAD, and then discuss in more detail our rationale for investigating the effects of therapeutic agents that restore impaired mitochondrial bioenergetics in the CNS. Specifically, we focus on agents that either work in part through K-ATP channels, present in both mitochondria and plasma membranes, and agents that work to weakly uncouple the respiratory capacity of the electron transport chain in mitochondria from ATP production. We propose these agents may be complementary to currently available antiretroviral agents and may significantly improve the capacity of CNS infected with HIV-1 to meet increased bioenergetic demands involved in normal synaptic communication.
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Affiliation(s)
- S W Perry
- Center for Aging and Developmental Biology, Kornberg Medical Research Institute, Rochester, NY 14642, USA
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Kaul M, Lipton SA. Experimental and potential future therapeutic approaches for HIV-1 associated dementia targeting receptors for chemokines, glutamate and erythropoietin. Neurotox Res 2005; 8:167-86. [PMID: 16260394 DOI: 10.1007/bf03033828] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Severe and debilitating neurological problems that include behavioral abnormalities, motor dysfunction and frank dementia can occur after infection with the human immunodeficiency virus-1 (HIV-1). Infected peripheral immune-competent cells, in particular macrophages, infiltrate the central nervous system (CNS) and provoke a neuropathological response involving all cell types in the brain. HIV-1 infection results in activation of chemokine receptors, inflammatory mediators, extracellular matrix-degrading enzymes and glutamate receptor-mediated excitotoxicity, all of which can trigger numerous downstream signaling pathways that result in disruption of neuronal and glial function. Despite many major improvements in the control of viral infection in the periphery, a truly effective therapy for HIV-1 associated dementia is currently not available. This review will discuss experimental and potentially future therapeutic strategies based on recently uncovered pathologic mechanisms contributing to neuronal damage induced by HIV-1.
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Affiliation(s)
- M Kaul
- Center for Neuroscience and Aging Research, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
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46
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Chen W, Tang Z, Fortina P, Patel P, Addya S, Surrey S, Acheampong EA, Mukhtar M, Pomerantz RJ. Ethanol potentiates HIV-1 gp120-induced apoptosis in human neurons via both the death receptor and NMDA receptor pathways. Virology 2005; 334:59-73. [PMID: 15749123 DOI: 10.1016/j.virol.2005.01.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2004] [Revised: 01/05/2005] [Accepted: 01/10/2005] [Indexed: 01/13/2023]
Abstract
Neuronal loss is a hallmark of AIDS dementia syndromes. Human immunodeficiency virus type I (HIV-1)-specific proteins may induce neuronal apoptosis, but the signal transduction of HIV-1 gp120-induced, direct neuronal apoptosis remains unclear. Ethanol (EtOH) is considered to be an environmental co-factor in AIDS development. However, whether EtOH abuse in patients with AIDS increases neuronal dysfunction is still uncertain. Using pure, differentiated, and post-mitotic NT2.N-derived human neurons, we investigated the mechanisms of HIV-1 and/or EtOH-related direct neuronal injury and the molecular interactions between HIV-1-specific proteins and EtOH. It was demonstrated that NT2.N neurons were susceptible to HIV-1 Bal (R5-tropic strain) gp120-induced direct cell death. Of importance, EtOH induced cell death in human neurons in a clinically-relevant dose range and EtOH strongly potentiated HIV-1 gp120-induced neuronal injury at low and moderate concentrations. Furthermore, this potentiation of neurotoxicity could be blocked by N-methyl-D-aspartate (NMDA) receptor subunit 2B (NR2B) antagonists. We analyzed human genomic profiles in these human neurons, using Affymetrix genomics technology, to elucidate the apoptotic pathways involved in HIV-1- and EtOH-related neurodegeneration. Our findings indicated significant over-expression of selected apoptosis functional genes. Significant up-regulation of TRAF5 gene expression may play an essential role in triggering potentiation by EtOH of HIV-1 gp120-induced neuronal apoptosis at early stages of interaction. These studies suggested that two primary apoptotic pathways, death receptor (extrinsic) and NMDA receptor (intrinsic)-related programmed cell-death pathways, are both involved in the potentiation by EtOH of HIV-1 gp120-induced direct human neuronal death. Thus, these data suggest rationally-designed, molecular targets for potential anti-HIV-1 neuroprotection.
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Affiliation(s)
- Wei Chen
- Center for Human Virology and Biodefense, Division of Infectious Diseases and Environmental Medicine, Thomas Jefferson University, 1020 Locust Street, Suite 329, Philadelphia, PA 19107, USA
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Abstract
Human immunodeficiency virus (HIV) infection is often complicated by the development of acquired immunodeficiency syndrome (AIDS) dementia complex (ADC). Quinolinic acid (QUIN) is an end product of tryptophan, metabolized through the kynurenine pathway (KP) that can act as an endogenous brain excitotoxin when produced and released by activated macrophages/microglia, the very cells that are prominent in the pathogenesis of ADC. This review examines QUIN's involvement in the features of ADC and its role in pathogenesis. We then synthesize these findings into a hypothetical model for the role played by QUIN in ADC, and discuss the implications of this model for ADC and other inflammatory brain diseases.
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Affiliation(s)
- Gilles J Guillemin
- Centre for Immunology, Department of Neurology, St Vincent's Hospital, Sydney, Australia
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Walsh KA, Megyesi JF, Wilson JX, Crukley J, Laubach VE, Hammond RR. Antioxidant protection from HIV-1 gp120-induced neuroglial toxicity. J Neuroinflammation 2004; 1:8. [PMID: 15285794 PMCID: PMC483061 DOI: 10.1186/1742-2094-1-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2004] [Accepted: 05/27/2004] [Indexed: 11/17/2022] Open
Abstract
Background The pathogenesis of HIV-1 glycoprotein 120 (gp120) associated neuroglial toxicity remains unresolved, but oxidative injury has been widely implicated as a contributing factor. In previous studies, exposure of primary human central nervous system tissue cultures to gp120 led to a simplification of neuronal dendritic elements as well as astrocytic hypertrophy and hyperplasia; neuropathological features of HIV-1-associated dementia. Gp120 and proinflammatory cytokines upregulate inducible nitric oxide synthase (iNOS), an important source of nitric oxide (NO) and nitrosative stress. Because ascorbate scavenges reactive nitrogen and oxygen species, we studied the effect of ascorbate supplementation on iNOS expression as well as the neuronal and glial structural changes associated with gp120 exposure. Methods Human CNS cultures were derived from 16–18 week gestation post-mortem fetal brain. Cultures were incubated with 400 μM ascorbate-2-O-phosphate (Asc-p) or vehicle for 18 hours then exposed to 1 nM gp120 for 24 hours. The expression of iNOS and neuronal (MAP2) and astrocytic (GFAP) structural proteins was examined by immunohistochemistry and immunofluorescence using confocal scanning laser microscopy (CSLM). Results Following gp120 exposure iNOS was markedly upregulated from undetectable levels at baseline. Double label CSLM studies revealed astrocytes to be the prime source of iNOS with rare neurons expressing iNOS. This upregulation was attenuated by the preincubation with Asc-p, which raised the intracellular concentration of ascorbate. Astrocytic hypertrophy and neuronal injury caused by gp120 were also prevented by preincubation with ascorbate. Conclusions Ascorbate supplementation prevents the deleterious upregulation of iNOS and associated neuronal and astrocytic protein expression and structural changes caused by gp120 in human brain cell cultures.
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Affiliation(s)
- Kimberley A Walsh
- Department of Pathology, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
| | - Joseph F Megyesi
- Department of Pathology, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
- Department Clinical Neurological Sciences, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
| | - John X Wilson
- Department Physiology, University of Western Ontario, London, ON, Canada
| | - Jeff Crukley
- Department of Pathology, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
| | - Victor E Laubach
- Department of Surgery, University of Virginia Health System, Charlottesville, VA, USA
| | - Robert R Hammond
- Department of Pathology, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
- Department Clinical Neurological Sciences, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
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Iskander S, Walsh KA, Hammond RR. Human CNS cultures exposed to HIV-1 gp120 reproduce dendritic injuries of HIV-1-associated dementia. J Neuroinflammation 2004; 1:7. [PMID: 15285795 PMCID: PMC483060 DOI: 10.1186/1742-2094-1-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2004] [Accepted: 05/27/2004] [Indexed: 11/16/2022] Open
Abstract
HIV-1-associated dementia remains a common subacute to chronic central nervous system degeneration in adult and pediatric HIV-1 infected populations. A number of viral and host factors have been implicated including the HIV-1 120 kDa envelope glycoprotein (gp120). In human post-mortem studies using confocal scanning laser microscopy for microtubule-associated protein 2 and synaptophysin, neuronal dendritic pathology correlated with dementia. In the present study, primary human CNS cultures exposed to HIV-1 gp120 at 4 weeks in vitro suffered gliosis and dendritic damage analogous to that described in association with HIV-1-associated dementia.
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Affiliation(s)
- Sam Iskander
- Department of Pathology, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
| | - Kimberley A Walsh
- Department of Pathology, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
| | - Robert R Hammond
- Department of Pathology, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
- Department of Clinical Neurological Sciences, London Health Sciences Centre, University of Western Ontario, London, ON, Canada
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Nargi-Aizenman JL, Havert MB, Zhang M, Irani DN, Rothstein JD, Griffin DE. Glutamate receptor antagonists protect from virus-induced neural degeneration. Ann Neurol 2004; 55:541-9. [PMID: 15048893 DOI: 10.1002/ana.20033] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Neuronal damage during acute viral encephalomyelitis can result directly from virus infection or indirectly from the host immune response to infection. In neurodegenerative diseases and stroke, neuronal death also can result from excess release of excitatory amino acid neurotransmitters, such as glutamate. To determine the role of glutamate excitotoxicity in fatal alphavirus-induced paralytic encephalomyelitis, we treated mice infected with neuroadapted Sindbis virus (NSV) with antagonists of N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) subtypes of glutamate receptors. Both apoptotic and necrotic neurons in the hippocampus were decreased in animals treated with MK-801, an NMDA receptor antagonist, or GYKI-52466, an AMPA receptor antagonist. However, only AMPA receptor blockade prevented damage to spinal cord motor neurons and protected mice from paralysis and death due to NSV infection. Protection was not caused by altered virus replication because treatment did not affect virus distribution and actually delayed virus clearance. These results provide evidence that NSV infection activates neurotoxic pathways that result in aberrant glutamate receptor stimulation and neuronal damage. Furthermore, AMPA receptor-mediated motor neuron death is an important contributor to paralysis and mortality in acute alphavirus-induced encephalomyelitis.
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Affiliation(s)
- Jennifer L Nargi-Aizenman
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
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