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Williams ME, Naudé PJW. The relationship between HIV-1 neuroinflammation, neurocognitive impairment and encephalitis pathology: A systematic review of studies investigating post-mortem brain tissue. Rev Med Virol 2024; 34:e2519. [PMID: 38282400 PMCID: PMC10909494 DOI: 10.1002/rmv.2519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 01/12/2024] [Accepted: 01/17/2024] [Indexed: 01/30/2024]
Abstract
The activities of HIV-1 in the central nervous system (CNS) are responsible for a dysregulated neuroinflammatory response and the subsequent development of HIV-associated neurocognitive disorders (HAND). The use of post-mortem human brain tissue is pivotal for studying the neuroimmune mechanisms of CNS HIV infection. To date, numerous studies have investigated HIV-1-induced neuroinflammation in post-mortem brain tissue. However, from the commonly investigated studies in this line of research, it is not clear which neuroinflammatory markers are consistently associated with HIV neurocognitive impairment (NCI) and neuropathology (i.e., HIV-encephalitis, HIVE). Therefore, we conducted a systematic review of the association between neuroinflammation and NCI/HIVE from studies investigating post-mortem brain tissue. Our aim was to synthesise the published data to date to provide commentary on the most noteworthy markers that are associated with NCI/HIVE. PubMed, Scopus, and Web of Science databases were searched using a search protocol designed specifically for this study. Sixty-one studies were included that investigated the levels of inflammatory markers based on their gene and protein expression in association with NCI/HIVE. The findings revealed that the (1) transcript expressions of IL-1β and TNF-α were consistently associated with NCI/HIVE, whereas CCL2 and IL-6 were commonly not associated with NCI/HIVE, (2) protein expressions of CD14, CD16, CD68, Iba-1, IL-1β and TNF-α were consistently associated with NCI/HIVE, while CD45, GFAP, HLA-DR, IL-1 and IL-6 were commonly not associated with NCI/HIVE, and (3) gene and protein expressions of CNS IL-1β and TNF-α were consistently associated with NCI/HIVE, while IL-6 was consistently not associated with NCI/HIVE. These markers highlight the commonly investigated markers in this line of research and elucidates the neuroinflammatory mechanisms in the HIV-1 brain that are involved in the pathophysiology of NCI/HIVE. These markers and related pathways should be investigated for the development of improved diagnostics, prognostics, and therapeutics of HAND.
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Affiliation(s)
| | - Petrus J. W. Naudé
- Department of Psychiatry and Mental HealthUniversity of Cape TownCape TownSouth Africa
- Neuroscience InstituteUniversity of Cape TownCape TownSouth Africa
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Pandey HS, Seth P. Friends Turn Foe-Astrocytes Contribute to Neuronal Damage in NeuroAIDS. J Mol Neurosci 2019; 69:286-297. [PMID: 31236774 DOI: 10.1007/s12031-019-01357-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 06/12/2019] [Indexed: 02/07/2023]
Abstract
Astrocytes play a wide variety of roles in the central nervous system (CNS). Various facets of astrocyte-neuron interplay, investigated for the past few decades, have placed these most abundant and important glial cell types to be of supreme importance for the maintenance of the healthy CNS. Interestingly, glial dysfunctions have proven to be the major contributor to neuronal loss in several CNS disorders and pathologies. Specifically, in the field of neuroAIDS, glial dysfunction-mediated neuronal stress is a major factor contributing to the HIV-1 neuropathogenesis. As there is increasing evidence that astrocytes harbor HIV-1 and serve as "safe haven" for the dormant virus in the brain, the indirect pathway of neuronal damage has taken over the direct neuronal damage in its contribution to HIV-1 neuropathogenesis. In this review, we provide a brief insight into the astrocyte functions and dysfunctions in different CNS conditions with an elaborated insight into neuroAIDS. Detailed understanding of the role of astrocytes in neuroAIDS will help in the better therapeutic management of the neurological problems associated with HIV-1 patients.
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Affiliation(s)
- Hriday Shanker Pandey
- Department of Cellular and Molecular Neuroscience, Neurovirology Section, National Brain Research Centre (NBRC), Nainwal Road, NH-8, Manesar, Gurgaon, Haryana, 122052, India
| | - Pankaj Seth
- Department of Cellular and Molecular Neuroscience, Neurovirology Section, National Brain Research Centre (NBRC), Nainwal Road, NH-8, Manesar, Gurgaon, Haryana, 122052, India.
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Zhou F, Liu X, Zuo D, Xue M, Gao L, Yang Y, Wang J, Niu L, Cao Q, Li X, Hua H, Zhang B, Hu M, Gao D, Zheng K, Izumiya Y, Tang R. HIV-1 Nef-induced lncRNA AK006025 regulates CXCL9/10/11 cluster gene expression in astrocytes through interaction with CBP/P300. J Neuroinflammation 2018; 15:303. [PMID: 30382871 PMCID: PMC6208068 DOI: 10.1186/s12974-018-1343-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 10/23/2018] [Indexed: 01/04/2023] Open
Abstract
Background HIV-associated neurocognitive disorder (HAND) is a neurodegenerative disease associated with persistent neuroinflammation and subsequent neuron damage. Pro-inflammatory factors and neurotoxins from activated astrocytes by HIV-1 itself and its encoded proteins, including the negative factor (Nef), are involved in the pathogenesis of HAND. This study was designed to find potential lncRNAs that regulate astrocyte functions and inflammation process. Methods We performed microarray analysis of lncRNAs from primary mouse astrocytes treated with Nef protein. Top ten lncRNAs were validated through real-time PCR analysis. Gene ontology (GO) and KEGG pathway analysis were applied to explore the potential functions of lncRNAs. RIP and ChIP assays were performed to demonstrate the mechanism of lncRNA regulating gene expression. Results There were 638 co-upregulated lncRNAs and 372 co-downregulated lncRNAs in primary astrocytes treated with Nef protein for both 6 h and 12 h. GO and KEGG pathway analysis showed that the biological functions of top differential-expressed mRNAs were associated with inflammatory cytokines and chemokine. Knockdown of lncRNA AK006025, not AK138360, inhibited significantly CXCL9, CXCL10 (IP-10), and CXCL11 expression in astrocytes treated with Nef protein. Mechanism study showed that AK006025 associated with CBP/P300 was enriched in the promoter of CXCL9, CXCL10, and CXCL11 genes. Conclusions Our findings uncovered the expression profiles of lncRNAs and mRNAs in vitro, which might help to understand the pathways that regulate astrocyte activation during the process of HAND. Electronic supplementary material The online version of this article (10.1186/s12974-018-1343-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Feng Zhou
- Jiangsu Key Laboratory of Brain Disease Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China. .,Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China.
| | - Xiaomei Liu
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Dongjiao Zuo
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Min Xue
- Department of Physiology, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Lin Gao
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Ying Yang
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Jing Wang
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Liping Niu
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Qianwen Cao
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Xiangyang Li
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Hui Hua
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Bo Zhang
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Minmin Hu
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Dianshuai Gao
- Department of Neurobiology and Anatomy, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Kuiyang Zheng
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China
| | - Yoshihiro Izumiya
- Department of Dermatology, University of California Davis (UC Davis) School of Medicine, Sacramento, CA, USA
| | - Renxian Tang
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogen Biology and Immunology and Laboratory of Infection and Immunity, Xuzhou Medical University, Xuzhou, 221004, Jiangsu, People's Republic of China.
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Thaney VE, Sanchez AB, Fields JA, Minassian A, Young JW, Maung R, Kaul M. Transgenic mice expressing HIV-1 envelope protein gp120 in the brain as an animal model in neuroAIDS research. J Neurovirol 2017; 24:156-167. [PMID: 29075998 DOI: 10.1007/s13365-017-0584-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 09/03/2017] [Accepted: 09/27/2017] [Indexed: 01/08/2023]
Abstract
HIV-1 infection causes injury to the central nervous system (CNS) and is often associated with neurocognitive disorders. One model for brain damage seen in AIDS patients is the transgenic (tg) mouse expressing a soluble envelope protein gp120 of HIV-1 LAV in the brain in astrocytes under the control of the promoter of glial fibrillary acidic protein. These GFAP-gp120tg mice manifest several key neuropathological features observed in AIDS brains, such as decreased synaptic and dendritic density, increased numbers of activated microglia, and pronounced astrocytosis. Several recent studies show that brains of GFAP-gp120tg mice and neurocognitively impaired HIV patients share also a significant number of differentially regulated genes, activation of innate immunity and other cellular signaling pathways, disturbed neurogenesis, and learning deficits. These findings support the continued relevance of the GFAP-gp120tg mouse as a useful model to investigate neurodegenerative mechanisms and develop therapeutic strategies to mitigate the consequences associated with HIV infection of the CNS, neuroAIDS, and HAND.
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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
| | - Ana B Sanchez
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Jerel A Fields
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Arpi Minassian
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Jared W Young
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Ricky Maung
- 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, La Jolla, CA, 92093, USA. .,Division of Biomedical Sciences, School of Medicine, University of California, Riverside, 900 University Ave, Riverside, CA, 92521, USA.
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Avraham HK, Jiang S, Fu Y, Rockenstein E, Makriyannis A, Zvonok A, Masliah E, Avraham S. The cannabinoid CB₂ receptor agonist AM1241 enhances neurogenesis in GFAP/Gp120 transgenic mice displaying deficits in neurogenesis. Br J Pharmacol 2014; 171:468-79. [PMID: 24148086 DOI: 10.1111/bph.12478] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 09/12/2013] [Accepted: 10/03/2013] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE HIV-1 glycoprotein Gp120 induces apoptosis in rodent and human neurons in vitro and in vivo. HIV-1/Gp120 is involved in the pathogenesis of HIV-associated dementia (HAD) and inhibits proliferation of adult neural progenitor cells (NPCs) in glial fibrillary acidic protein (GFAP)/Gp120 transgenic (Tg) mice. As cannabinoids exert neuroprotective effects in several model systems, we examined the protective effects of the CB₂ receptor agonist AM1241 on Gp120-mediated insults on neurogenesis. EXPERIMENTAL APPROACH We assessed the effects of AM1241 on survival and apoptosis in cultures of human and murine NPCs with immunohistochemical and TUNEL techniques. Neurogenesis in the hippocampus of GFAP/Gp120 transgenic mice in vivo was also assessed by immunohistochemistry. KEY RESULTS AM1241 inhibited in vitro Gp120-mediated neurotoxicity and apoptosis of primary human and murine NPCs and increased their survival. AM1241 also promoted differentiation of NPCs to neuronal cells. While GFAP/Gp120 Tg mice exhibited impaired neurogenesis, as indicated by reduction in BrdU⁺ cells and doublecortin⁺ (DCX⁺) cells, and a decrease in cells with proliferating cell nuclear antigen (PCNA), administration of AM1241 to GFAP/Gp120 Tg mice resulted in enhanced in vivo neurogenesis in the hippocampus as indicated by increase in neuroblasts, neuronal cells, BrdU⁺ cells and PCNA⁺ cells. Astrogliosis and gliogenesis were decreased in GFAP/Gp120 Tg mice treated with AM1241, compared with those treated with vehicle. CONCLUSIONS AND IMPLICATIONS The CB₂ receptor agonist rescued impaired neurogenesis caused by HIV-1/Gp120 insult. Thus, CB₂ receptor agonists may act as neuroprotective agents, restoring impaired neurogenesis in patients with HAD.
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Affiliation(s)
- Hava Karsenty Avraham
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
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Glutamate metabolism and HIV-associated neurocognitive disorders. J Neurovirol 2014; 20:315-31. [PMID: 24867611 DOI: 10.1007/s13365-014-0258-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 03/14/2014] [Accepted: 05/09/2014] [Indexed: 12/21/2022]
Abstract
HIV-1 infection can lead to neurocognitive impairment collectively known as HIV-associated neurocognitive disorders (HAND). Although combined antiretroviral treatment (cART) has significantly ameliorated HIV's morbidity and mortality, persistent neuroinflammation and neurocognitive dysfunction continue. This review focuses on the current clinical and molecular evidence of the viral and host factors that influence glutamate-mediated neurotoxicity and neuropathogenesis as an important underlying mechanism during the course of HAND development. In addition, discusses potential pharmacological strategies targeting the glutamatergic system that may help prevent and improve neurological outcomes in HIV-1-infected subjects.
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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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Kang YJ, Digicaylioglu M, Russo R, Kaul M, Achim CL, Fletcher L, Masliah E, Lipton SA. Erythropoietin plus insulin-like growth factor-I protects against neuronal damage in a murine model of human immunodeficiency virus-associated neurocognitive disorders. Ann Neurol 2010; 68:342-52. [PMID: 20818790 DOI: 10.1002/ana.22070] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Prolonged human immunodeficiency virus-1 (HIV-1) infection leads to neurological debilitation, including motor dysfunction and frank dementia. Although pharmacological control of HIV infection is now possible, HIV-associated neurocognitive disorders (HAND) remain intractable. Here, we report that chronic treatment with erythropoietin (EPO) and insulin-like growth factor-I (IGF-I) protects against HIV/gp120-mediated neuronal damage in culture and in vivo. METHODS Initially, we tested the neuroprotective effects of various concentrations of EPO, IGF-I, or EPO+IGF-I from gp120-induced damage in vitro. To assess the chronic effects of EPO+IGF-I administration in vivo, we treated HIV/gp120-transgenic or wild-type mice transnasally once a week for 4 months and subsequently conducted immunohistochemical analyses. RESULTS Low concentrations of EPO+IGF-I provided neuroprotection from gp120 in vitro in a synergistic fashion. In vivo, EPO+IGF-I treatment prevented gp120-mediated neuronal loss, but did not alter microgliosis or astrocytosis. Strikingly, in the brains of both humans with HAND and gp120-transgenic mice, we found evidence for hyperphosphorylated tau protein (paired helical filament-I tau), which has been associated with neuronal damage and loss. In the mouse brain following transnasal treatment with EPO+IGF-I, in addition to neuroprotection we observed increased phosphorylation/activation of Akt (protein kinase B) and increased phosphorylation/inhibition of glycogen synthase kinase (GSK)-3beta, dramatically decreasing downstream hyperphosphorylation of tau. These results indicate that the peptides affected their cognate signaling pathways within the brain parenchyma. INTERPRETATION Our findings suggest that chronic combination therapy with EPO+IGF-I provides neuroprotection in a mouse model of HAND, in part, through cooperative activation of phosphatidylinositol 3-kinase/Akt/GSK-3beta signaling. This combination peptide therapy should therefore be tested in humans with HAND.
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Affiliation(s)
- Yeon-Joo Kang
- Del E Webb Center for Neuroscience, Aging, and Stem Cell Research, Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
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Perdan K, Lipnik‐Štangelj M, Kržan M. Chapter 8 The Impact of Astrocytes in the Clearance of Neurotransmitters by Uptake and Inactivation. ADVANCES IN PLANAR LIPID BILAYERS AND LIPOSOMES 2009. [DOI: 10.1016/s1554-4516(09)09008-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Kasyanov A, Tamamura H, Fujii N, Xiong H. HIV-1 gp120 enhances giant depolarizing potentials via chemokine receptor CXCR4 in neonatal rat hippocampus. Eur J Neurosci 2006; 23:1120-8. [PMID: 16553776 DOI: 10.1111/j.1460-9568.2006.04646.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In the immature hippocampus, the giant depolarizing potentials (GDPs) are recurrent network-driven synaptic events generated by gamma-aminobutyric acid (GABA), which in neonatal life is depolarizing and excitatory. The GDPs enable a high degree of synchrony in immature neurons and participate in activity-dependent growth and synapse formation. To understand how human immunodeficiency virus type one (HIV-1) infection in the immature brain impairs brain growth and development, we studied the effects of HIV-1 envelope glycoprotein, gp120, a viral toxin shed in abundance by infected cells, on spontaneous occurring GDPs recorded in the CA3 pyramidal cells in neonatal (P2-P6) Sprague-Dawley rat hippocampal slices using whole-cell patch technique. Bath application of gp120 produced a sustained enhancement of GDP frequency in a concentration-dependent manner without affecting passive membrane properties, suggesting that the site of action is most likely on neural network, other than on the recorded neurons. The gp120-induced enhancement of GDPs was blocked by T140, a highly specific antagonist for the chemokine receptor, CXCR4, indicating the involvement of CXCR4 in the gp120-induced increase of GDPs. Bath application of stromal cell-derived factor-1alpha (SDF-1alpha), the only CXCR4 ligand, mimicked the effects of gp120 on GDPs, supporting the engagement of CXCR4 receptors in the gp120-induced increase of GDP occurrence. Further studies revealed the involvement of protein kinase A/C in the gp120-induced enhancement of GDPs. These results demonstrate that gp120 enhances GDPs in the neonatal rat hippocampus. This enhancement may cause an excessive increase in intracellular calcium and resultant neuronal injury, leading to retardation of the brain and behavioural development as seen in paediatric AIDS patients.
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Affiliation(s)
- Alexander Kasyanov
- Neurophysiology Laboratory, Center for Neurovirology and Neurodegenerative Disorders, University of Nebraska Medical Center, Omaha, USA
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Holguin A, O'Connor KA, Biedenkapp J, Campisi J, Wieseler-Frank J, Milligan ED, Hansen MK, Spataro L, Maksimova E, Bravmann C, Martin D, Fleshner M, Maier SF, Watkins LR. HIV-1 gp120 stimulates proinflammatory cytokine-mediated pain facilitation via activation of nitric oxide synthase-I (nNOS). Pain 2004; 110:517-530. [PMID: 15288392 DOI: 10.1016/j.pain.2004.02.018] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2003] [Revised: 12/31/2003] [Accepted: 02/17/2004] [Indexed: 10/26/2022]
Abstract
It has become clear that spinal cord glia (microglia and astrocytes) importantly contribute to the creation of exaggerated pain responses. One model used to study this is peri-spinal (intrathecal, i.t.) administration of gp120, an envelope protein of HIV-1 known to activate glia. Previous studies demonstrated that i.t. gp120 produces pain facilitation via the release of glial proinflammatory cytokines. The present series of studies tested whether spinal nitric oxide (NO) contributes to i.t. gp120-induced mechanical allodynia and, if so, what effect NO has on spinal proinflammatory cytokines. gp120 stimulation of acutely isolated lumbar dorsal spinal cords released NO as well as proinflammatory cytokines (tumor necrosis factor-alpha, interleukin-1beta (IL1), interleukin-6 (IL6)), thus identifying NO as a candidate mediator of gp120-induced behavioral effects. Behaviorally, identical effects were observed when gp120-induced mechanical allodynia was challenged by i.t. pre-treatment with either a broad-spectrum nitric oxide synthase (NOS) inhibitor (L-NAME) or 7-NINA, a selective inhibitor of NOS type-I (nNOS). Both abolished gp120-induced mechanical allodynia. While the literature pre-dominantly documents that proinflammatory cytokines stimulate the production of NO rather than the reverse, here we show that gp120-induced NO increases proinflammatory cytokine mRNA levels (RT-PCR) and both protein expression and protein release (serial ELISA). Furthermore, gp120 increases mRNA for IL1 converting enzyme and matrix metalloproteinase-9, enzymes responsible for activation and release of proinflammatory cytokines.
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Affiliation(s)
- Adelina Holguin
- Department of Psychology and the Center for Neuroscience, University of Colorado at Boulder, Boulder, CO 80309, USA Department of Kinesiology and Applied Physiology, and the Center for Neuroscience, University of Colorado at Boulder, Boulder, CO 80309, USA Department of Pharmacology, Amgen, Thousand Oaks, CA 91320, USA
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Navarra M, Baltrons MA, Sardón T, Pedraza CE, García A. HIV-1 coat protein gp120 decreases NO-dependent cyclic GMP accumulation in rat brain astroglia by increasing cyclic GMP phosphodiesterase activity. Neurochem Int 2004; 45:937-46. [PMID: 15312988 DOI: 10.1016/j.neuint.2004.03.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The human immunodeficiency virus type-1 (HIV-1) coat glycoprotein gp120 has been proposed as a likely etiologic agent of HIV-associated dementia (HAD). The pathogenic mechanisms underlying HAD have not yet been fully elucidated, but different evidences indicate that glial cells play an essential role in the development and amplification of the disease. The NO/cyclic GMP (cGMP) system is a widespread signal transduction pathway in the CNS involved in numerous physiological and pathological functions. Increased expression of NO synthase has been reported in the brain of AIDS patients and in cultured rodent glial cells exposed to gp120. The aim of this study was to investigate if gp120 could cause alterations in the metabolism of the NO physiological messenger cGMP that could contribute to the pathogenesis of HAD. Here, we show that long-term treatment (more than 24 h) of rat cerebellar astrocyte-enriched cultures with gp120 (10 nM) induces changes in the cultured cells--astrocyte stellation and proliferation of ameboid microglia--compatible with the acquisition of a reactive phenotype and reduces the capacity of the astrocytes to accumulate cGMP in response to NO in a time-dependent manner (maximal after 72 h). Measurements in cell extracts show that gp120 enhances Ca2+-independent cGMP phosphodiesterase activity by 80-100% without significantly affecting soluble guanylyl cyclase (sGC). Experiments in whole cells using specific phosphodiesterase inhibitors indicate that the viral protein increases the activity of cGMP specific phosphodiesterase 5.
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Affiliation(s)
- Michele Navarra
- Instituto de Biotecnología y Biomedicina V. Villar Palasí and Departamento de Bioquímica y Biología Molecular, Universidad Autónoma de Barcelona, 08193 Bellaterra, Spain
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Abstract
Human immunodeficiency virus type I (HIV-1) infection leads to penetration of the central nervous system (CNS) in virtually all infected individuals and HIV-1-induced encephalopathy in a significant number of untreated patients. The molecular mechanisms by which HIV-1 enters the CNS and yields CNS dysfunction are still unclear. Our laboratories and others have begun to explore the direct effects of prioritized HIV-1-specific proteins on diverse human CNS cell types. One of these proteins, the accessory HIV-1 protein Vpr, is a critical moiety in these studies, and will be discussed in this article.
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Affiliation(s)
- Roger J Pomerantz
- Biochemistry and Molecular Pharmacology, Division of Infectious Disease and Environmental Medicine, Center for Human Virology and Biodefense, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
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Fatemi SH, Emamian ES, Sidwell RW, Kist DA, Stary JM, Earle JA, Thuras P. Human influenza viral infection in utero alters glial fibrillary acidic protein immunoreactivity in the developing brains of neonatal mice. Mol Psychiatry 2003; 7:633-40. [PMID: 12140787 DOI: 10.1038/sj.mp.4001046] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2000] [Revised: 08/15/2001] [Accepted: 09/24/2001] [Indexed: 11/08/2022]
Abstract
Epidemiological reports describe a strong association between prenatal human influenza viral infection and later development of schizophrenia. Postmodern human brain studies, however, indicate a lack of gliosis in schizophrenic brains presumably secondary to absence of glial cells during the second trimester viral infection in utero. We hypothesized that human influenza infection in day 9 pregnant mice would alter the expression of glial fibrillary acidic protein (GFAP, an important marker of gliosis, neuron migration, and reactive injury) in developing brains of postnatal days 0, 14 and 35 mice. Determination of cellular GFAP immunoreactivity (IR) expressed as cell density in cortex and hippocampus of control and experimental brains showed increases in GFAP-positive density in exposed cortical (P = 0.03 day 14 vs control) and hippocampal cells (P = 0.035 day 14, P = 0.034 day 35). Similarly, ependymal cell layer GFAP-IR cell counts showed increases with increasing brain age from day 0, to days 14 and 35 in infected groups (P = 0.037, day 14) vs controls. The GFAP-positive cells in prenatally exposed brains showed 'hypertrophy' and more stellate morphology. These results implicate a significant role of prenatal human influenza viral infection on subsequent gliosis, which persists throughout brain development in mice from birth to adolescence.
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Affiliation(s)
- S H Fatemi
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, Minneapolis, MN, USA.
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16
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Neurotoxic Activity of the HIV-1 Envelope Glycoprotein: Activation of Protein Kinase C in Rat Astrocytes. Int J Mol Sci 2002. [DOI: 10.3390/i3111105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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17
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Minagar A, Shapshak P, Fujimura R, Ownby R, Heyes M, Eisdorfer C. The role of macrophage/microglia and astrocytes in the pathogenesis of three neurologic disorders: HIV-associated dementia, Alzheimer disease, and multiple sclerosis. J Neurol Sci 2002; 202:13-23. [PMID: 12220687 DOI: 10.1016/s0022-510x(02)00207-1] [Citation(s) in RCA: 405] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Macrophage/microglia (M phi) are the principal immune cells in the central nervous system (CNS) concomitant with inflammatory brain disease and play a significant role in the host defense against invading microorganisms. Astrocytes, as a significant component of the blood-brain barrier, behave as one of the immune effector cells in the CNS as well. However, both cell types may play a dual role, amplifying the effects of inflammation and mediating cellular damage as well as protecting the CNS. Interactions of the immune system, M phi, and astrocytes result in altered production of neurotoxins and neurotrophins by these cells. These effects alter the neuronal structure and function during pathogenesis of HIV-1-associated dementia (HAD), Alzheimer disease (AD), and multiple sclerosis (MS). HAD primarily involves subcortical gray matter, and both HAD and MS affect sub-cortical white matter. AD is a cortical disease. The process of M phi and astrocytes activation leading to neurotoxicity share similarities among the three diseases. Human Immunodeficiency Virus (HIV)-1-infected M phi are involved in the pathogenesis of HAD and produce toxic molecules including cytokines, chemokines, and nitric oxide (NO). In AD, M phis produce these molecules and are activated by beta-amyloid proteins and related oligopeptides. Demyelination in MS involves M phi that become lipid laden, spurred by several possible antigens. In these three diseases, cytokine/chemokine communications between M phi and astrocytes occur and are involved in the balance of protective and destructive actions by these cells. This review describes the role of M phi and astrocytes in the pathogenesis of these three progressive neurological diseases, examining both beneficent and deleterious effects in each disease.
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Affiliation(s)
- Alireza Minagar
- Department of Neurology, Louisiana State University School of Medicine, Shreveport, LA 71130, USA.
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18
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Li H, Haviv YS, Derdeyn CA, Lam J, Coolidge C, Hunter E, Curiel DT, Blackwell JL. Human immunodeficiency virus type 1-mediated syncytium formation is compatible with adenovirus replication and facilitates efficient dispersion of viral gene products and de novo-synthesized virus particles. Hum Gene Ther 2001; 12:2155-65. [PMID: 11779400 DOI: 10.1089/10430340152710504] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Conditionally replicative adenovirus (CRAd) vectors are designed for specific oncolytic replication in tumor tissues with concomitant sparing of normal cells. As such, CRAds offer an unprecedented level of anticancer potential for malignancies that have been refractory to previous cancer gene therapy interventions. CRAd efficacy may, however, be compromised by inefficient dispersion of the replicating vector within the tumor tissue. To address this issue, we evaluated the utility of a fusogenic membrane glycoprotein (FMG), which induces the fusion of neighboring cellular membranes to form multinucleated syncytia. We hypothesized that the FMG-mediated syncytia would facilitate dispersion of the adenovirus (Ad) gene products and viral progeny. To test this, human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins, which induce syncytia in the presence of CD4+ target cells, were expressed by an Ad (Ad5HIVenv) in permissive (CD4-positive) and nonpermissive (CD4-negative) cell lines. After validating this Ad-FMG model, the efficiency of Ad replication in the presence or absence of syncytia was evaluated. The results demonstrated that syncytium formation was compatible with Ad replication and dramatically increased the dispersion of virus gene products within the cytoplasm of the syncytia as well as viral particles in the nuclei of the syncytial mass. Moreover, progeny virions were released more efficiently from syncytia compared with nonsyncytial cells. These data demonstrate the utility of FMGs as a dispersion agent and suggest that FMGs can improve the efficacy of CRAd gene therapy.
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Affiliation(s)
- H Li
- Division of Human Gene Therapy, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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19
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Milligan ED, O'Connor KA, Armstrong CB, Hansen MK, Martin D, Tracey KJ, Maier SF, Watkins LR. Systemic administration of CNI-1493, a p38 mitogen-activated protein kinase inhibitor, blocks intrathecal human immunodeficiency virus-1 gp120-induced enhanced pain states in rats. THE JOURNAL OF PAIN 2001; 2:326-33. [PMID: 14622812 DOI: 10.1054/jpai.2001.26174] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Intrathecal administration of the human immunodeficiency virus-1 envelope glycoprotein, gp120, activates astrocytes and microglia to release products that induce thermal hyperalgesia and mechanical allodynia. Both pain states are disrupted by intrathecal CNI-1493, a p38 mitogen-activated protein (MAP) kinase inhibitor. Whether CNI-1493, or any other p38 MAP kinase inhibitor, can cross the blood-brain barrier to affect spinal cord function is unknown. Given that several such drugs are in clinical trials, it is of interest to determine whether they may be potentially useful in treating centrally mediated pain. The aim of the present studies was to determine whether systemic CNI-1493 could block intrathecal gp120-induced thermal hyperalgesia and/or mechanical allodynia. Because p38 MAP kinase inhibition would be expected to prevent proinflammatory cytokine release and/or signal transduction, we sought to determine from the same animals the likely mechanism by which CNI-1493 blocks gp120-induced pain states. These studies show that systemic CNI-1493 blocks intrathecal gp120-induced thermal hyperalgesia and mechanical allodynia. Because CNI-1493 did not block proinflammatory cytokine release, this may suggest disruption at the level of signal transduction. These studies provide the first evidence that systemic p38 MAP kinase inhibitors can prevent centrally mediated exaggerated pain states. Thus, CNI-1493 may provide a novel therapeutic approach for the treatment of pain.
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Affiliation(s)
- E D Milligan
- Department of Psychology and Center for Neurosciences, University of Colorado at Boulder, 80309, USA
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20
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Asensio VC, Maier J, Milner R, Boztug K, Kincaid C, Moulard M, Phillipson C, Lindsley K, Krucker T, Fox HS, Campbell IL. Interferon-independent, human immunodeficiency virus type 1 gp120-mediated induction of CXCL10/IP-10 gene expression by astrocytes in vivo and in vitro. J Virol 2001; 75:7067-77. [PMID: 11435587 PMCID: PMC114435 DOI: 10.1128/jvi.75.15.7067-7077.2001] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The CXC chemokine gamma interferon (IFN-gamma)-inducible protein CXCL10/IP-10 is markedly elevated in cerebrospinal fluid and brain of individuals infected with human immunodeficiency virus type 1 (HIV-1) and is implicated in the pathogenesis of HIV-associated dementia (HAD). To explore the possible role of CXCL10/IP-10 in HAD, we examined the expression of this and other chemokines in the central nervous system (CNS) of transgenic mice with astrocyte-targeted expression of HIV gp120 under the control of the glial fibrillary acidic protein (GFAP) promoter, a murine model for HIV-1 encephalopathy. Compared with wild-type controls, CNS expression of the CC chemokine gene CCL2/MCP-1 and the CXC chemokine genes CXCL10/IP-10 and CXCL9/Mig was induced in the GFAP-HIV gp120 mice. CXCL10/IP-10 RNA expression was increased most and overlapped the expression of the transgene-encoded HIV gp120 gene. Astrocytes and to a lesser extent microglia were identified as the major cellular sites for CXCL10/IP-10 gene expression. There was no detectable expression of any class of IFN or their responsive genes. In astrocyte cultures, soluble recombinant HIV gp120 protein was capable of directly inducing CXCL10/IP-10 gene expression a process that was independent of STAT1. These findings highlight a novel IFN- and STAT1-independent mechanism for the regulation of CXCL10/IP-10 expression and directly link expression of HIV gp120 to the induction of CXCL10/IP-10 that is found in HIV infection of the CNS. Finally, one function of IP-10 expression may be the recruitment of leukocytes to the CNS, since the brain of GFAP-HIV gp120 mice had increased numbers of CD3(+) T cells that were found in close proximity to sites of CXCL10/IP-10 RNA expression.
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Affiliation(s)
- V C Asensio
- Department of Neuropharmacology, The Scripps Research Institute, La Jolla, California 92037, USA
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21
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Kaul M, Garden GA, Lipton SA. Pathways to neuronal injury and apoptosis in HIV-associated dementia. Nature 2001; 410:988-94. [PMID: 11309629 DOI: 10.1038/35073667] [Citation(s) in RCA: 906] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Human immunodeficiency virus-1 (HIV-1) can induce dementia with alarming occurrence worldwide. The mechanism remains poorly understood, but discovery in brain of HIV-1-binding sites (chemokine receptors) provides new insights. HIV-1 infects macrophages and microglia, but not neurons, although neurons are injured and die by apoptosis. The predominant pathway to neuronal injury is indirect through release of macrophage, microglial and astrocyte toxins, although direct injury by viral proteins might also contribute. These toxins overstimulate neurons, resulting in the formation of free radicals and excitotoxicity, similar to other neurodegenerative diseases. Recent advances in understanding the signalling pathways mediating these events offer hope for 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, California 92037, USA
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22
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Pittaluga A, Pattarini R, Feligioni M, Raiteri M. N-methyl-D-aspartate receptors mediating hippocampal noradrenaline and striatal dopamine release display differential sensitivity to quinolinic acid, the HIV-1 envelope protein gp120, external pH and protein kinase C inhibition. J Neurochem 2001; 76:139-48. [PMID: 11145986 DOI: 10.1046/j.1471-4159.2001.00057.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
NMDA receptors regulating hippocampal noradrenaline (NA) and striatal dopamine (DA) release have been compared using superfused synaptosomes prelabelled with the [(3)H]catecholamines. Both receptors mediated release augmentation when exposed to NMDA plus glycine. Quinolinic acid (100 microM or 1 mM) plus glycine (1 microM)-elicited [(3)H]NA, but not [(3)H]DA release. The NMDA (100 microM)-evoked release of [(3)H]NA and [(3)H]DA was similar and concentration-dependently enhanced by glycine or D-serine (0.1-1 microM); in contrast, the HIV-1 envelope protein gp120 potently (30-100 pM) enhanced the NMDA-evoked release of [(3)H]NA, but not that of [(3)H]DA. Gp120 also potentiated quinolinate-evoked [(3)H]NA release. Ifenprodil (0.1-0.5 microM) or CP-101,606 (0.1-10 microM) inhibited the NMDA plus glycine-evoked release of both [(3)H]catecholamines. Zinc (0.1-1 microM) was ineffective. Lowering external pH from 7.4 to 6.6 strongly inhibited the release of [(3)H]NA elicited by NMDA plus glycine, whereas the release of [(3)H]DA was unaffected. The protein kinase C inhibitors GF 109203X (0.1 microM) or H7 (10 microM) selectively prevented the effect of NMDA plus glycine on the release of [(3)H]NA. GF 109203X also blocked the release of [(3)H]NA induced by NMDA or quinolinate plus gp120. It is concluded that the hippocampal NMDA receptor and the striatal NMDA receptor are pharmacologically distinct native subtypes, possibly containing NR2B subunits but different splice variants of the NR1 subunit.
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Affiliation(s)
- A Pittaluga
- Dipartimento di Medicina Sperimentale, Sezione di Farmacologia e Tossicologia, Università di Genova, Italy.
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23
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Huang MB, Bond VC. Involvement of protein kinase C in HIV-1 gp120-induced apoptosis in primary endothelium. J Acquir Immune Defic Syndr 2000; 25:375-89. [PMID: 11141237 DOI: 10.1097/00042560-200012150-00001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We previously showed that HIV-1 gp120-induced apoptosis in primary human umbilical vein endothelial cell cultures (HUVEC), through CCR5 and CXCR4. Here, we have found that agonists of protein kinase C (PKC), basic fibroblast growth factor (bFGF), and short exposure to low concentrations of phorbol esters were found to block gp120-induced apoptosis in HUVEC cultures. PKC antagonists, sphingosine, H7, and extended exposure of cultures to high concentrations of phorbol esters were also found to block gp120-induced apoptosis in HUVEC cultures. A significant increase in the total amount of cellular PKC enzymatic activity was observed on exposure of HUVEC to gp120. No increase in total PKC activity was observed on exposure of HUVECs to the natural ligands SDF-1alpha, or regulated-on-activation normal T-expressed and secreted (RANTES) cells, and gp120-induced PKC induction was found to be totally blocked by CXCR4 antibodies and partially blocked by the caspase 3 inhibitor, DEVD-CHO. Alternatively, CXCR4 antibodies and DEVD-CHO totally blocked apoptosis. Finally, gp120-induced effects were found to be insensitive to pertussis toxin. Accumulated evidence suggests PKC involvement at multiple points in the gp120-induced apoptotic pathway; also suggests involvement of the CXCR4 receptor internalization pathway, and potentially suggests different downstream effects of gp120-receptor interactions and natural ligand-receptor interactions.
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Affiliation(s)
- M B Huang
- Department of Biochemistry, Morehouse School of Medicine, Atlanta, Georgia 30310-1495, USA
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24
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Involvement of Protein Kinase C in HIV-1 gp120-Induced Apoptosis in Primary Endothelium. J Acquir Immune Defic Syndr 2000. [DOI: 10.1097/00126334-200012150-00001] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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25
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Abstract
This review examines the interaction of steroid hormones, glucocorticoids and estrogen, and gp120, a possible causal agent of acquired immune deficiency syndrome-related dementia complex. The first part of the review examines the data and mechanisms by which gp120 may cause neurotoxicity and by which these steroid hormones effect cell death in general. The second part of the review summarizes recent experiments that show how these steroid hormones can modulate the toxic effects of gp120 and glucocorticoids exacerbating toxicity, and estrogen decreasing it. We then examine the limited in vivo and clinical data relating acquired immune deficiency syndrome-related dementia complex and steroid hormones and speculate on the possible clinical significance of these findings with respect to acquired immune deficiency syndrome-related dementia complex.
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Affiliation(s)
- S M Brooke
- Department of Biological Sciences, Stanford University, Stanford, California 94305, USA
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26
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Smits HA, Boven LA, Pereira CF, Verhoef J, Nottet HS. Role of macrophage activation in the pathogenesis of Alzheimer's disease and human immunodeficiency virus type 1-associated dementia. Eur J Clin Invest 2000; 30:526-35. [PMID: 10849022 DOI: 10.1046/j.1365-2362.2000.00661.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The structure and function of neurons are changed not only during development of the central nervous system but also in certain neurological disorders, such as Alzheimer's disease and human immunodeficiency virus type 1 (HIV-1) -associated dementia. Immunological activation and altered production of neurotoxins and neurotrophins by brain macrophages are thought to play an important role in neuronal structure and function. This review describes the clinical and pathological features of both Alzheimer's disease and HIV-1-associated dementia and tries to interpret the role of the macrophage and astrocytes therein. The consequences of activation of macrophages by amyloid-beta in Alzheimer's disease and HIV infection of macrophages in HIV-1-associated dementia and the similarities between these diseases will be discussed. Although the neuropathology of Alzheimer's disease and HIV-1-associated dementia differs, Alzheimer's disease is a cortical dementia and HIV-1-associated dementia is a subcortical dementia, the process of macrophage activation and the resulting pathways leading to neurotoxicity seem very similar. In both Alzheimer's disease and HIV-1-associated dementia, interaction of macrophages and astrocytes appear to play an important role.
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Affiliation(s)
- H A Smits
- University Medical Cluster Utrecht, The Netherlands
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27
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Frigg R, Klein MA, Hegyi I, Zinkernagel RM, Aguzzi A. Scrapie pathogenesis in subclinically infected B-cell-deficient mice. J Virol 1999; 73:9584-8. [PMID: 10516067 PMCID: PMC112993 DOI: 10.1128/jvi.73.11.9584-9588.1999] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/1999] [Accepted: 07/26/1999] [Indexed: 11/20/2022] Open
Abstract
Prion infections can present without clinical manifestations. B-cell deficiency may be a model for subclinical transmissible spongiform encephalopathy, since it protects mice from disease upon intraperitoneal administration of scrapie prions; however, a proportion of B-cell-deficient mice accumulate protease-resistant prion protein in their brains. Here, we have characterized this subclinical disease. In addition, we have studied the possibility that a neurotoxic factor secreted by B cells may contribute to pathogenesis.
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Affiliation(s)
- R Frigg
- Institutes of Neuropathology, Department of Pathology, CH-8091 Zurich, Switzerland
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28
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Xu X, Yang D, Wyss-Coray T, Yan J, Gan L, Sun Y, Mucke L. Wild-type but not Alzheimer-mutant amyloid precursor protein confers resistance against p53-mediated apoptosis. Proc Natl Acad Sci U S A 1999; 96:7547-52. [PMID: 10377452 PMCID: PMC22123 DOI: 10.1073/pnas.96.13.7547] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Amyloid precursor proteins (APPs) are expressed in multiple organs and cell types in diverse species. Their conservation across species and high abundance in brain and the association of various APP missense mutations with autosomal dominant forms of familial Alzheimer's disease (FAD) suggest important roles for APP in the central nervous system. However, the basic functions of APP in the central nervous system remain largely unknown. To assess potential effects of APP on neuronal death and survival, we transfected APP-deficient rat neuroblastoma cells (B103) with DNA constructs encoding wild-type or FAD-mutant human APP. Wild-type, but not FAD-mutant, APP effectively protected cells against apoptosis induced by ultraviolet irradiation, staurosporine, or p53. Wild-type APP also strongly inhibited p53 DNA-binding activity and p53-mediated gene transactivation, whereas FAD-mutant APP did not. We conclude that APP protects neuronal cells against apoptosis by controlling p53 activation at the post-translational level. Disruption of this function by mutations or alterations in APP processing could enhance neuronal vulnerability to secondary insults and contribute to neuronal degeneration.
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Affiliation(s)
- X Xu
- Gladstone Institute of Neurological Disease, University of California, San Francisco, CA 94141-9100, USA
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29
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Goekjian PG, Wu GZ, Chen S, Zhou L, Jirousek MR, Gillig JR, Ballas LM, Dixon JT. Synthesis of Fluorinated Macrocyclic Bis(indolyl)maleimides as Potential 19F NMR Probes for Protein Kinase C. J Org Chem 1999. [DOI: 10.1021/jo9808876] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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30
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Sauder C, de la Torre JC. Cytokine expression in the rat central nervous system following perinatal Borna disease virus infection. J Neuroimmunol 1999; 96:29-45. [PMID: 10227422 DOI: 10.1016/s0165-5728(98)00272-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Borna disease virus (BDV) causes central nervous system (CNS) disease in several vertebrate species, which is frequently accompanied by behavioral abnormalities. In the adult rat, intracerebral (i.c.) BDV infection leads to immunomediated meningoencephalitis. In contrast, i.c. infection of neonates causes a persistent infection in the absence of overt signs of brain inflammation. These rats (designated PTI-NB) display distinct behavioral and neurodevelopmental abnormalities. However, the molecular mechanisms for these virally induced CNS disturbances are unknown. Cytokines play an important role in CNS function, both under normal physiological and pathological conditions. Astrocytes and microglia are the primary resident cells of the central nervous system with the capacity to produce cytokines. Strong reactive astrocytosis is observed in the PTI-NB rat brain. We have used a ribonuclease protection assay to investigate the mRNA expression levels of proinflammatory cytokines in different brain regions of PTI-NB and control rats. We show here evidence of a chronic upregulation of proinflammatory cytokines interleukin-6, tumor necrosis factor alpha, interleukins-1alpha, and -1beta in the hippocampus and cerebellum of the PTI-NB rat brain. These brain regions exhibited only a very mild and transient immune infiltration. In contrast, in addition to reactive astrocytes, a strong and sustained microgliosis was observed in the PTI-NB rat brains. Our data suggest that CNS resident cells, namely astrocytes and microglia, are the major source of cytokine expression in the PTI-NB rat brain. The possible implications of these findings are discussed.
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Affiliation(s)
- C Sauder
- Department of Neuropharmacology, The Scripps Research Institute, La Jolla, CA 92037, USA
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31
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Marshall DC, Wyss-Coray T, Abraham CR. Induction of matrix metalloproteinase-2 in human immunodeficiency virus-1 glycoprotein 120 transgenic mouse brains. Neurosci Lett 1998; 254:97-100. [PMID: 9779929 DOI: 10.1016/s0304-3940(98)00674-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Human immunodeficiency virus (HIV)-1 can invade the brain and cause degeneration of the central nervous system, resulting in a host of cognitive and motor impairments. HIV-1 glycoprotein 120 (gp120), has been implicated in the neurodegenerative effects of HIV infection. Here, gp120's neurotoxic potential is demonstrated in both transgenic mice and cultured cells. We observed that gp120 causes an induction of matrix metalloproteinase (MMP)-2 activity and protein in transgenic mouse brains and in transfected C6 cells. We propose that induced MMP-2 may contribute to a neurodegenerative environment by degrading extracellular matrix (ECM) fibronectin and type IV collagen.
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Affiliation(s)
- D C Marshall
- Department of Biochemistry, The Arthritis Center, Boston University School of Medicine, MA 02118-2394, USA
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32
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Sawaya BE, Thatikunta P, Denisova L, Brady J, Khalili K, Amini S. Regulation of TNFalpha and TGFbeta-1 gene transcription by HIV-1 Tat in CNS cells. J Neuroimmunol 1998; 87:33-42. [PMID: 9670843 DOI: 10.1016/s0165-5728(98)00044-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Tat is a transcription transactivator produced by the human immunodeficiency virus type 1 (HIV-1) at the early phase of infection and plays a critical role in the expression and replication of the viral genome. This 86 amino acid protein, which can be secreted from the infected cells, has the ability to enter uninfected cells and exert its activity upon the responsive genes. Earlier results indicated that in addition to the HIV-1 promoter, Tat has the capacity to induce transcription of a variety of cellular genes. In this study, we demonstrate that exposure of cells from the central nervous system (U-87MG and SK-N-MC) and the lymphoid T cells (Jurkat) to highly purified Tat increases transcriptional activity of the reporter constructs containing the promoters from the transforming growth factor beta-1 (TGFbeta-1), the tumor necrosis factor alpha (TNFalpha), and the HIV-1 LTR. In addition, Tat treatment results in increased levels of TGFbeta-1 and TNFalpha mRNAs in these cells. Activation of the TGFbeta-1 and TNFalpha promoter constructs by Tat in U-87MG and SK-N-MC cells required amino acid residues 2 to 36 which spans the acidic and the cysteine-rich domains of Tat. In both CNS and lymphoid cells, the level of endogenous TGFbeta-1 mRNA was increased by mutant Tat protein containing amino acids 1 to 48 but not with a mutant Tat protein with a deletion between residues 2 to 36. TNFalpha mRNA level was increased by mutant Tat spanning residues 1 to 48 in U-87MG cells, but not in SK-N-MC and Jurkat cells. These observations suggest that activation of cellular and viral genes by Tat in various cells may be mediated by different pathways as evidenced by the requirements of the different regions of Tat. Activation of the TGFbeta-1 and TNFalpha promoters by wild-type Tat was severely affected by the mutant peptides spanning residues 2 to 36 and 1 to 48 suggesting that both truncated Tat peptides may function as dominant negative mutants over TNFalpha and TGFbeta-1 gene transcription. The importance of these findings in Tat-induced regulation of viral and cellular genes in various cell types is discussed.
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Affiliation(s)
- B E Sawaya
- Center for NeuroVirology and NeuroOncology, Department of Neurology, Allegheny University of Health Sciences, Philadelphia, PA 19102, USA
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33
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Rabbi MF, al-Harthi L, Saifuddin M, Roebuck KA. The cAMP-dependent protein kinase A and protein kinase C-beta pathways synergistically interact to activate HIV-1 transcription in latently infected cells of monocyte/macrophage lineage. Virology 1998; 245:257-69. [PMID: 9636365 DOI: 10.1006/viro.1998.9158] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The HIV-1 long terminal repeat (LTR) responds to a variety of cellular signal transduction pathways. We demonstrate that the cAMP-dependent protein kinase A (PKA) and protein kinase C (PKC) signaling pathways synergize to increase HIV-1 LTR-mediated transcription and viral replication in a latently infected promonocytic cell line (U1). The LTR-mediated synergy induced by cholera toxin (Ctx), a potent activator of the cAMP-dependent PKA pathway, and the PKC activator phorbol 12-myristate 13-acetate (PMA) was abrogated by a PKC-beta-specific inhibitor (LY333531). In contrast, the LTR-mediated synergy induced by Ctx and TNF alpha was not affected by LY333531. The synergy induced by Ctx and TNF alpha was also abrogated by mutation of the cAMP-responsive downstream sequence elements (DSE) in the 5' untranslated leader region, whereas the DSE mutations did not affect the synergy induced by Ctx and PMA. These distinctions indicate that Ctx cooperates differently with TNF alpha and PMA to activate the HIV-1 LTR. Ctx and PMA synergistically activated AP-1- and NF-kappa B-dependent transcription, even though no cooperative binding of AP-1 or NF-kappa B was observed in gel shift assays. An extensive mutational analysis of the HIV-1 LTR that included the NF-kappa B and AP-1 binding sites revealed no distinct cis-acting element or region within the HIV-1 LTR that was required for the transcriptional synergy. Ctx and PMA also synergistically interact to activate the HTLV-1 LTR. These results indicate that the transcriptional synergy elicited by Ctx and PMA targets multiple functional elements and promoters, requires a cooperative interaction between the PKA and PKC-beta pathways, and differs mechanistically from the transcriptional synergy induced by Ctx and TNF alpha.
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Affiliation(s)
- M F Rabbi
- Department of Immunology/Microbiology, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA
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Masliah E, Raber J, Alford M, Mallory M, Mattson MP, Yang D, Wong D, Mucke L. Amyloid protein precursor stimulates excitatory amino acid transport. Implications for roles in neuroprotection and pathogenesis. J Biol Chem 1998; 273:12548-54. [PMID: 9575214 DOI: 10.1074/jbc.273.20.12548] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Excitatory neurotransmitters such as glutamate are required for the normal functioning of the central nervous system but can trigger excitotoxic neuronal injury if allowed to accumulate to abnormally high levels. Their extracellular levels are controlled primarily by transmitter uptake into astrocytes. Here, we demonstrate that the amyloid protein precursor may participate in the regulation of this important process. The amyloid protein precursor has been well conserved through evolution, and a number of studies indicate that it may function as an endogenous excitoprotectant. However, the mechanisms underlying this neuroprotective capacity remain largely unknown. At moderate levels of expression, human amyloid protein precursors increased glutamate/aspartate uptake in brains of transgenic mice, with the 751-amino acid isoform showing greater potency than the 695-amino acid isoform. Cerebral glutamate/aspartate transporter protein levels were higher in transgenic mice than in non-transgenic controls, whereas transporter mRNA levels were unchanged. Amyloid protein precursor-dependent stimulation of aspartate uptake by cultured primary astrocytes was associated with increases in protein kinase A and C activity and could be blocked by inhibitors of these kinases. The stimulation of astroglial excitatory amino acid transport by amyloid protein precursors could protect the brain against excitotoxicity and may play an important role in neurotransmission.
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Affiliation(s)
- E Masliah
- Departments of Neurosciences and Pathology, University of California San Diego, La Jolla, California 92093-0624, USA
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35
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Avgeropoulos N, Kelley B, Middaugh L, Arrigo S, Persidsky Y, Gendelman HE, Tyor WR. SCID mice with HIV encephalitis develop behavioral abnormalities. JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES AND HUMAN RETROVIROLOGY : OFFICIAL PUBLICATION OF THE INTERNATIONAL RETROVIROLOGY ASSOCIATION 1998; 18:13-20. [PMID: 9593453 DOI: 10.1097/00042560-199805010-00003] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Severe combined immunodeficient (SCID) mice inoculated intracerebrally (i.c.) with HIV-infected human monocytes develop brain pathology similar to that in humans with HIV encephalitis. This includes HIV-positive macrophages and multinucleated giant cells, astrogliosis, microglial nodules, and neuronal dropout. These xenografts survive about 1 month. To develop a model of chronic HIV encephalitis and to assay the resulting behavioral abnormalities, we reinoculated SCID mice i.c. every 4 weeks for 3 months with either HIV-infected human monocytes (n = 5) or uninfected human macrophages (n = 4) or administered no inoculation (n = 6); these three groups were monitored for behavioral abnormalities. Tests of cognitive function in a Morris water maze 3.5 months after the first inoculation suggested that HIV-infected mice performed poorly compared with controls. Following testing in the water maze on days 4 and 5 of acquisition, motor activity of infected mice was reduced in comparison with that of controls. Retention of goal location when tested 1 week later was impaired in HIV-infected mice compared with controls. Histopathologic analysis of brains revealed significant astrogliosis and strongly suggested higher numbers of major histocompatibility complex (MHC) class II-positive multinucleated macrophages in HIV-infected compared with control mice. Thus, our preliminary studies indicate that SCID mice with HIV encephalitis develop behavioral abnormalities reminiscent of human disease. These behavioral abnormalities are associated with significantly increased astrogliosis, the presence of HIV, and probably multinucleated giant cells. These studies further support the use of this SCID animal model system for studies of the pathogenesis of HIV encephalitis and for drug interventions.
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Affiliation(s)
- N Avgeropoulos
- Department of Neurology, Medical University of South Carolina, Charleston 29425, USA
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36
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Zhang S, Racaniello VR. Persistent echovirus infection of mouse cells expressing the viral receptor VLA-2. Virology 1997; 235:293-301. [PMID: 9281509 DOI: 10.1006/viro.1997.8692] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mouse cells are not susceptible to infection with echovirus 1 (EV-1) because they lack the viral receptor, human VLA-2. Two mouse fibroblast cell lines, L cells and 3T3 cells, were made susceptible to EV-1 infection after transformation with cDNAs of human VLA-2. After EV-1 infection, L cell transformants of human VLA-2 (alpha2beta1 L cells) develop cytopathic effect (CPE) as expected, while 3T3 cell transformants of human VLA-2 (alpha2beta1 3T3 cells) or the alpha2 subunit of human VLA-2 (alpha2 3T3 cells) become persistently infected. The distinct outcome is not a result of differential virus growth on these transformants because one-step growth curve analysis reveals little difference in EV-1 replication in both cell lines. In addition, 3T3 cell transformants expressing the poliovirus receptor (Pvr 3T3 cells) are lysed during poliovirus infection, suggesting that 3T3 cells are not intrinsically resistant to CPE caused by enterovirus infection. The results of limit dilution assays indicate that all EV-1-infected alpha2 3T3 cells produce infectious virus. All EV-1-infected alpha2 3T3 cells remain viable after EV-1 infection, and the kinetics of cell growth were not altered. FACS analysis reveals that receptor down-regulation is not involved in the establishment of persistent infection. Furthermore, inhibition of host protein synthesis was not observed in EV-1-infected alpha2 3T3 or alpha2beta1 L cells. Since alpha2beta1 L cells are lysed by EV-1 infection, these findings suggest that virus-induced translation inhibition is not a determinant of cell killing.
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Affiliation(s)
- S Zhang
- Department of Microbiology, Columbia University College of Physicians and Surgeons, 701 West 168th Street, New York, New York, 10032, USA
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Vesce S, Bezzi P, Rossi D, Meldolesi J, Volterra A. HIV-1 gp120 glycoprotein affects the astrocyte control of extracellular glutamate by both inhibiting the uptake and stimulating the release of the amino acid. FEBS Lett 1997; 411:107-9. [PMID: 9247152 DOI: 10.1016/s0014-5793(97)00674-1] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The mechanisms of HIV-1 neurotoxicity remain still undefined although the induction of signalling events and a modest inhibition of glutamate uptake induced by the envelope glycoprotein, gp120, have called attention to astrocytes. Here we demonstrate that the levels at which the viral glycoprotein affects glutamate homeostasis of astrocyte cultures are at least two: not only the inhibition of uptake, due to an effect at site(s) away from the transporters of the amino acid but also a slow stimulation of release. The combination of these two events accounts for a considerable steady increase of the extracellular concentration of the excitatory amino acid which could play an important role in the neurotoxicity often observed in AIDS patients.
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Affiliation(s)
- S Vesce
- Institute of Pharmacological Sciences, University of Milan, Italy
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Masliah E, Westland CE, Rockenstein EM, Abraham CR, Mallory M, Veinberg I, Sheldon E, Mucke L. Amyloid precursor proteins protect neurons of transgenic mice against acute and chronic excitotoxic injuries in vivo. Neuroscience 1997; 78:135-46. [PMID: 9135095 DOI: 10.1016/s0306-4522(96)00553-2] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The beta-amyloid protein precursor (APP) is well conserved across different species and may fulfill important physiological functions within the CNS. While high-level neuronal expression of amyloidogenic forms of human APP results in beta-amyloid production and neurodegeneration, lower levels of neuronal human APP expression in neurons of transgenic mice may primarily accentuate physiological functions of this molecule. To assess the neuroprotective potential of human APP in vivo, mice from seven distinct transgenic lines expressing different human APP isoforms from the neuron-specific enolase promoter were challenged with systemic kainate injections (n=30) or transgene-mediated glial expression of gp120 (n=32), an HIV-1 protein capable of inducing excitotoxic neuronal damage. To quantitate human APP-mediated neuroprotection. the area of neuropil occupied by presynaptic terminals and neuronal dendrites in the neocortex and hippocampus of each mouse was determined using laser scanning confocal microscopy of double-immunolabelled brain sections and computer-aided image analysis. Compared with gp120 singly transgenic controls, mice from three of three human APP751gp120 bigenic lines expressing the 751 amino acid form of human APP at low levels showed significant protection against degeneration of presynaptic terminals; two of these lines also showed significantly less damage to neuronal dendrites. Two of three human APP695/gp120 bigenic lines expressing human APP695 at low levels were protected against presynaptic and dendritic damage, whereas one low expressor line and a human APP695/gp120 bigenic line expressing human APP695 at higher levels showed no significant protection. In the corresponding human APP singly transgenic lines, overexpressing only specific human APP isoforms, significant protection against kainate-induced degeneration of presynaptic terminals and neuronal dendrites was found in two of three human APP751 lines and not in any of the four human APP695 lines tested. These results indicate that human APP can protect neurons against chronic and acute excitotoxic insults in vivo and that human APP isoforms differ in their neuroprotective potential, at least with respect to specific forms of neural injury. It is therefore possible that impairments of neuroprotective human APP functions or aberrant shifts in human APP isoform ratios could contribute to neurodegeneration.
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Affiliation(s)
- E Masliah
- Department of Neurosciences, University of California at San Diego, La Jolla 92093-0624, U.S.A
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