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Abstract
Neurodegenerative and infectious disorders including Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis, and stroke are rapidly increasing as population's age. Alzheimer's disease alone currently affects 4.5 million Americans, and more than $100 billion is spent per year on medical and institutional care for affected people. Such numbers will double in the ensuing decades. Currently disease diagnosis for all disorders is made, in large measure, on clinical grounds as laboratory and neuroimaging tests confirm what is seen by more routine examination. Achieving early diagnosis would enable improved disease outcomes. Drugs, vaccines or regenerative proteins present "real" possibilities for positively affecting disease outcomes, but are limited in that their entry into the brain is commonly restricted across the blood-brain barrier. This review highlights how these obstacles can be overcome by polymer science and nanotechnology. Such approaches may improve diagnostic and therapeutic outcomes. New developments in polymer science coupled with cell-based delivery strategies support the notion that diseases that now have limited therapeutic options can show improved outcomes by advances in nanomedicine.
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152
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Davis RL, Buck DJ, Saffarian N, Stevens CW. The opioid antagonist, beta-funaltrexamine, inhibits chemokine expression in human astroglial cells. J Neuroimmunol 2007; 186:141-9. [PMID: 17475341 PMCID: PMC1948894 DOI: 10.1016/j.jneuroim.2007.03.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 03/22/2007] [Accepted: 03/28/2007] [Indexed: 11/19/2022]
Abstract
Emerging evidence indicates that neuroinflammatory responses in astroglia, including chemokine expression, are altered by opioids. Astroglial chemokines, such as CXCL10, are instrumental in response to many neuropathological insults. Opioid mediated disruption of astroglial CXCL10 expression may be detrimental in opioid abusers or patients receiving acute opioid therapy. We have characterized the in vitro effects of opioids on CXCL10 protein expression in human astroglial (A172) cells. The proinflammatory cytokine, tumor necrosis factor (TNF)alpha induced CXCL10 expression in A172 cells. Using MG-132, helenalin and SN50 [inhibitors of the transcription factor, nuclear factor (NF)-kappaB], we determined that NF-kappaB activation is instrumental in TNFalpha-induced CXCL10 expression in A172 astroglia. Morphine exposure during the 24 h TNFalpha stimulation period did not alter CXCL10 expression. However, fentanyl, a more potent mu-opioid receptor (MOR) agonist, inhibited TNFalpha-induced CXCL10 expression. Interestingly, neither the non-selective opioid receptor antagonist, naltrexone nor beta-funaltrexamine (beta-FNA), a highly selective MOR antagonist, blocked fentanyl mediated inhibition of TNFalpha-induced CXCL10 expression. Rather, beta-FNA dose-dependently inhibited TNFalpha-induced CXCL10 expression with a greater potency than that observed for fentanyl. Immunoblot analysis indicated that morphine, fentanyl and beta-FNA each reduced TNFalpha-induced nuclear translocation of NF-kappaB p65. These data show that beta-FNA and fentanyl inhibit TNFalpha-induced CXCL10 expression via a MOR-independent mechanism. Data also suggest that inhibition of TNFalpha-induced CXCL10 expression by fentanyl and beta-FNA is not directly related to a reduction in NF-kappaB p65 nuclear translocation. Further investigation is necessary in order to fully elucidate the mechanism through which these two opioid compounds inhibit CXCL10 expression. Understanding the mechanism by which chemokine expression is suppressed, particularly by the opioid antagonist, beta-FNA, may provide insights into the development of safe and effective treatments for neuroinflammation.
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Affiliation(s)
- Randall L Davis
- Department of Pharmacology/Physiology, Oklahoma State University Center for Health Sciences, 1111 W. 17th Street, Tulsa, Oklahoma 74107, USA.
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153
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Ricardo-Dukelow M, Kadiu I, Rozek W, Schlautman J, Persidsky Y, Ciborowski P, Kanmogne GD, Gendelman HE. HIV-1 infected monocyte-derived macrophages affect the human brain microvascular endothelial cell proteome: new insights into blood-brain barrier dysfunction for HIV-1-associated dementia. J Neuroimmunol 2007; 185:37-46. [PMID: 17321604 PMCID: PMC2212599 DOI: 10.1016/j.jneuroim.2007.01.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Revised: 12/26/2006] [Accepted: 01/03/2007] [Indexed: 11/17/2022]
Abstract
Blood-brain barrier (BBB) compromise and transendothelial migration of HIV-infected leukocytes into the central nervous system (CNS) underlies the neuropathogenesis of HIV-1 infection. How this occurs is incompletely understood. We used a proteomic platform integrating difference gel electrophoresis and tandem mass spectrometry peptide sequencing to determine the effects that HIV-1-infected macrophages have on human brain microvascular endothelial cell (HBMEC) protein profiles. HIV-1 infected monocyte-derived macrophages (MDM) induced the upregulation of over 200 HBMEC proteins. These included metabolic, voltage-gated ion channels, heat shock, transport, cytoskeletal, regulatory, and calcium binding proteins. Results were validated by Western blot analysis. We conclude that HIV-1-infected MDM affect the HBMEC proteome and, in this way, affect BBB dysfunction and the development of HIV-1 CNS disease.
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Affiliation(s)
- Mary Ricardo-Dukelow
- Center for Neurovirology and Neurodegenerative Disorders, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5215, USA
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154
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Mu H, Chai H, Lin PH, Yao Q, Chen C. Current Update on HIV-associated Vascular Disease and Endothelial Dysfunction. World J Surg 2007; 31:632-43. [PMID: 17372667 DOI: 10.1007/s00268-006-0730-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Highly active antiretroviral therapy (HAART) has greatly reduced the risk of early death from opportunistic infections and extended the lifespan of people infected with the human immunodeficiency virus (HIV). Thus, many complications and organic damage in the HIV-infected population emerge. Cardiovascular disease as coronary artery disease has become a matter of particular concern. Its incidence is greatly increased in the HIV-infected population over that of people of the same age in the absence of general cardiovascular risk factors. Despite several clinical and laboratory studies in the association between HIV infection and cardiovascular disease, the pathogenic mechanisms of this significant clinical problem are largely unknown and are now under active investigation. Endothelial dysfunction is possibly the most plausible link between HIV infection and atherosclerosis. Increased expression of adhesion molecules such as intercellular adhesion molecule (ICAM)-1 and endothelial adhesion molecule (E-selectin) and inflammatory cytokines such as tumor necrosis factor (TNF)-alpha and interleukin (IL-6 has been reported in HIV-positive patients. The effect of HAART on endothelial function in HIV-positive patients is also demonstrated. In this review, we focus on the recent research update of HIV-associated vascular disease and vascular injury. We analyze and discuss the recent clinical and laboratory investigations on the effect of HIV, viral protein, and HAART therapy on endothelial injury and vascular disease; identify the areas of controversy and clinical relevance; and suggest some directions for future research.
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Affiliation(s)
- Hong Mu
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, One Baylor Plaza, Mail stop: NAB-2010, Houston, Texas 77030, USA
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155
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Calabria AR, Shusta EV. Blood-brain barrier genomics and proteomics: elucidating phenotype, identifying disease targets and enabling brain drug delivery. Drug Discov Today 2007; 11:792-9. [PMID: 16935746 DOI: 10.1016/j.drudis.2006.07.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Revised: 06/15/2006] [Accepted: 07/10/2006] [Indexed: 10/24/2022]
Abstract
The blood-brain barrier (BBB) regulates the passage of material between the bloodstream and the brain. Recent genomic and proteomic studies of the BBB have identified some of the unique molecular characteristics of this vascular bed, and have reinforced the concept that the BBB is heavily involved in brain function. Genomic and proteomic techniques have also been used to analyze the molecular events underlying diseases that have BBB involvement, such as multiple sclerosis, Alzheimer's disease, stroke and HIV-1 infection. It is expected that a better understanding of the complex mechanisms that link the BBB to neurological disease will ultimately lead to the development of innovative treatments.
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Affiliation(s)
- Anthony R Calabria
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706, USA
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156
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Kanmogne GD, Schall K, Leibhart J, Knipe B, Gendelman HE, Persidsky Y. HIV-1 gp120 compromises blood-brain barrier integrity and enhances monocyte migration across blood-brain barrier: implication for viral neuropathogenesis. J Cereb Blood Flow Metab 2007; 27:123-34. [PMID: 16685256 PMCID: PMC2232899 DOI: 10.1038/sj.jcbfm.9600330] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Human immunodeficiency virus-1 (HIV-1) encephalitis is characterized by brain infiltration of virus-infected monocytes and macrophages. Cellular products and viral proteins secreted by infected cells likely play an important role in blood-brain barrier (BBB) impairment and the development of HIV-1-associated dementia (HAD). We previously demonstrated that HIV-1 envelope glycoprotein gp120 induces toxicity and alters expression of tight junction proteins in human brain microvascular endothelial cells (HBMECs). Here, we delineate the mechanisms of gp120-induced BBB dysfunction. Human brain microvascular endothelial cells expressed HIV-1 co-receptors (CCR5 and CXCR4). Exposure of HBMECs to gp120 derived from macrophage (CCR5) or lymphocyte (CXCR4)-tropic viruses decreased BBB tightness, increased permeability, and enhanced monocyte migration across in vitro BBB models. Blood-brain barrier integrity was restored after gp120 removal. CCR5 antibodies and inhibitors of myosin light chain kinase or protein kinase C (PKC) blocked gp120-enhanced monocyte migration and permeability of BBB in vitro. Exposure of HBMECs to gp120 induced release of intracellular calcium ([Ca(2+)](i)) that was prevented by CCR5 antibody and partially blocked by CXCR4 antagonist. Human immunodeficiency virus-1 gp120 activated three PKC isoforms in HBMECs [PKC-alpha/betaII, PKC(pan)-betaII and PKC-zeta/lambda]. Furthermore, specific PKC inhibitors (acting at the ATP-binding and calcium release site) blocked gp120-induced PKC activation and prevented increase in BBB permeability, supporting the biologic significance of these results. Thus, gp120 can cause dysfunction of BBB via PKC pathways and receptor mediated [Ca(2+)](i) release leading to cytoskeletal alterations and increased monocyte migration.
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Affiliation(s)
- Georgette D Kanmogne
- Center for Neurovirology and Neurodegenerative Disorders, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA.
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157
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Acheampong E, Parveen Z, Mengistu A, Ngoubilly N, Wigdahl B, Lossinsky AS, Pomerantz RJ, Mukhtar M. Cholesterol-depleting statin drugs protect postmitotically differentiated human neurons against ethanol- and human immunodeficiency virus type 1-induced oxidative stress in vitro. J Virol 2006; 81:1492-501. [PMID: 17108035 PMCID: PMC1797499 DOI: 10.1128/jvi.01843-06] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The majority of human immunodeficiency virus type 1 (HIV-1)-infected individuals are either alcoholics or prone to alcoholism. Upon ingestion, alcohol is easily distributed into the various compartments of the body, particularly the brain, by crossing through the blood-brain barrier. Both HIV-1 and alcohol induce oxidative stress, which is considered a precursor for cytotoxic responses. Several reports have suggested that statins exert antioxidant as well as anti-inflammatory pleiotropic effects, besides their inherent cholesterol-depleting potentials. In our studies, postmitotically differentiated neurons were cocultured with HIV-1-infected monocytes, T cells, or their cellular supernatants in the presence of physiological concentrations of alcohol for 72 h. Parallel cultures were pretreated with statins (atorvastatin and simvastatin) with the appropriate controls, i.e., postmitotically differentiated neurons cocultured with uninfected cells and similar cultures treated with alcohol. The oxidative stress responses in the presence/absence of alcohol in these cultures were determined by the production of the well-characterized oxidative stress markers, 8-isoprostane-F2-alpha, total nitrates as an indicator for various isoforms of nitric oxide synthase activity, and heat shock protein 70 (Hsp70). An in vitro culture of postmitotically differentiated neurons with HIV-1-infected monocytes or T cells as well as supernatants from these cells enhanced the release of 8-isoprostane-F2-alpha in the conditioned medium six- to sevenfold (monocytes) and four- to fivefold (T cells). It was also observed that coculturing of HIV-1-infected primary monocytes over a time period of 72 h significantly elevated the release of Hsp70 compared with that of uninfected controls. Cellular supernatants of HIV-1-infected monocytes or T cells slightly increased Hsp70 levels compared to neurons cultured with uninfected monocytes or T-cell supernatants (controls). Ethanol (EtOH) presence further elevated Hsp70 in both infected and uninfected cultures. The amount of total nitrates was significantly elevated in the coculture system when both infected cells and EtOH were present. Surprisingly, pretreatment of postmitotic neurons with clinically available inhibitors of HMG-coenzyme A reductase (statins) inhibited HIV-1-induced release of stress/toxicity-associated parameters, i.e., Hsp70, isoprostanes, and total nitrates from HIV-1-infected cells. The results of this study provide new insights into HIV-1 neuropathogenesis aimed at the development of future HIV-1 therapeutics to eradicate viral reservoirs from the brain.
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Affiliation(s)
- Edward Acheampong
- Dorrance H. Hamilton Laboratories, Division of Infectious Diseases, Department of Medicine, Thomas Jefferson University, 1020 Locust Street, Suite 329, Philadelphia, Pennsylvania 19107, USA
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158
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Peters PJ, Dueñas-Decamp MJ, Sullivan WM, Clapham PR. Variation of macrophage tropism among HIV-1 R5 envelopes in brain and other tissues. J Neuroimmune Pharmacol 2006; 2:32-41. [PMID: 18040824 DOI: 10.1007/s11481-006-9042-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Accepted: 08/15/2006] [Indexed: 11/30/2022]
Abstract
Human immunodeficiency virus (HIV)-positive individuals frequently suffer from progressive encephelopathy, which is characterized by sensory neuropathy, sensory myelopathy, and dementia. Our group and others have reported the presence of highly macrophage-tropic R5 variants of HIV-1 in brain tissue of patients with neurological complications. These variants are able to exploit low amounts of CD4 and/or CCR5 for infection and potentially confer an expanded tropism for any cell types that express low CD4 and/or CCR5. In contrast to the brain-derived envelopes, we found that envelopes from lymph node tissue, blood, or semen were predominantly non-macrophage-tropic and required high amounts of CD4 for infection. Nevertheless, where tested, the non-macrophage-tropic envelopes conferred efficient replication in primary CD4(+) T-cell cultures. Determinants of R5 macrophage tropism appear to involve changes in the CD4 binding site, although further unknown determinants are also involved. The variation of R5 envelopes also affects their sensitivity to inhibition by ligands and entry inhibitors that target CD4 and CCR5. In summary, HIV-1 R5 viruses vary extensively in macrophage tropism. In the brain, highly macrophage-tropic variants may represent neurotropic or neurovirulent viruses. In addition, variation in R5 macrophage tropism may also have implications (1) for transmission, depending on what role macrophages or cells that express low CD4 and/or CCR5 play in the establishment of infection in a new host, and (2) for pathogenesis and depletion of CD4(+) T cells (i.e., do highly macrophage-tropic variants confer a broader tropism among CD4(+) T-cell populations late in disease and contribute to their depletion?).
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Affiliation(s)
- Paul J Peters
- Center for AIDS Research, Program in Molecular Medicine and Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, 373 Plantation Street Biotech II Suite 315, Worcester, MA 01605, USA
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159
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Abstract
Human immunodeficiency virus-1 (HIV-1) neuroinvasion occurs early (during period of initial viremia), leading to infection of a limited amount of susceptible cells with low CD4 expression. Protective cellular and humoral immunity eliminate and suppress viral replication relatively quickly due to peripheral immune responses and the low level of initial central nervous system (CNS) infection. Upregulation of the brain protective mechanisms against lymphocyte entry and survival (related to immune privilege) helps reduce viral load in the brain. The local immune compartment dictates local viral evolution as well as selection of cytotoxic lymphocytes and immunoglobulin G specificity. Such status can be sustained until peripheral immune anti-viral responses fail. Activation of microglia and astrocytes, due to local or peripheral triggers, increases chemokine production, enhances traffic of infected cells into the CNS, upregulates viral replication in resident brain macrophages, and significantly augments the spread of viral species. The combination of these factors leads to the development of HIV-1 encephalitis-associated neurocognitive decline and patient death. Understanding the immune-privileged state created by virus, the brain microenvironment, and the ability to enhance anti-viral immunity offer new therapeutic strategies for treatment of HIV-1 CNS infection.
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Affiliation(s)
- Yuri Persidsky
- Center for Neurovirology and Neurodegenerative Disorders, University of Nebraska Medical Center, Omaha, NE 68198-5215, USA.
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160
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Abstract
The pathogenesis of the human immunodeficiency virus (HIV) infection of the central nervous system and the imaging presentation of patients with neurological complications from HIV/AIDS are discussed. Imaging findings are often nonspecific; however, correlations with patient's clinical signs and CD4 count allow a working diagnosis to be made.
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Affiliation(s)
- Peter Corr
- Department of Radiology, Faculty of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, United Arab Emirates.
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161
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Santaguida S, Janigro D, Hossain M, Oby E, Rapp E, Cucullo L. Side by side comparison between dynamic versus static models of blood–brain barrier in vitro: A permeability study. Brain Res 2006; 1109:1-13. [PMID: 16857178 DOI: 10.1016/j.brainres.2006.06.027] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 04/12/2006] [Accepted: 06/11/2006] [Indexed: 11/15/2022]
Abstract
Endothelial cells in vivo are continuously exposed to shear stress, a tangential force generated by the flow of blood across their apical surfaces that affects endothelial cell structure and function. By contrast, the Transwell apparatus cannot reproduce the presence of intraluminal blood flow that is essential for the formation and differentiation of the BBB. In contrast, the dynamic in vitro model of the BBB (DIV-BBB) mimics both functionally and anatomically the brain microvasculature, creating quasi-physiological conditions for co-culturing human and non-human endothelial cells and astrocytes in a capillary-like structure. We used intraluminal bovine aortic endothelial cells (BAEC) co-cultured with extraluminal glial cells (C6) to obtain elevated trans-endothelial electrical resistance (TEER) and selective permeability to sucrose and phenytoin. The experiments were performed in parallel using Transwell systems DIV-BBB models and data were then cross compared. By contrast with Transwell, C6 and BAEC co-cultured in the DIV-BBB demonstrated predominantly aerobic metabolism evidenced by a robust increase in glucose consumption that was paralleled by a similar change in lactate production. BAEC exposed to glia under dynamic conditions grow in a monolayer fashion and developed a more stringent barrier as demonstrated by high TEER values and a selective permeability to [14C] phenytoin and the well-known paracellular marker [3H] sucrose. In conclusion, these data demonstrate that the exposure to intraluminal flow plays an essential role in promoting endothelial cell differentiation and increasing BBB tightness, thus making the use of the DIV-BBB well suited for pharmacological studies.
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Affiliation(s)
- Stefano Santaguida
- Division of Cerebrovascular Research, Cleveland Clinic Lerner College of Medicine, Cleveland, OH 44106, USA
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162
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Hayashi K, Pu H, Andras IE, Eum SY, Yamauchi A, Hennig B, Toborek M. HIV-TAT protein upregulates expression of multidrug resistance protein 1 in the blood-brain barrier. J Cereb Blood Flow Metab 2006; 26:1052-65. [PMID: 16395283 DOI: 10.1038/sj.jcbfm.9600254] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Central nervous system (CNS) complications of human immunodeficiency virus (HIV) infection remain a serious health risk in HIV/acquired immunodeficiency syndrome despite significant advances in highly active antiretroviral therapy (HAART). Specific drugs used for HAART are substrates for the efflux transport systems, such as the multidrug resistance-associated proteins (MRPs), which are present on brain microvascular endothelial cells (BMEC) and astrocytes, that is, the main cell types that form the blood-brain barrier (BBB). Thus, drugs employed in HAART are actively removed from the CNS and do not efficiently inhibit HIV replication in the brain. To study the potential mechanisms of this process, the aim of the present research was to address the hypothesis that HIV Tat protein can contribute to upregulation of MRP expression at the BBB level. Tat is a protein produced and released by HIV-infected cells, which may play an important role in brain vascular pathology in the course of HIV infection. Among the family of MRPs, exposure to Tat specifically induced MRP1 messenger ribonucleic acid and protein expression both in BMEC and astrocytes. These alterations were accompanied by enhanced MRP1-mediated efflux functions. Furthermore, activation of the mitogen-activated protein kinase signaling cascade was identified as the mechanism involved in Tat-mediated overexpression of MRP1. These results indicate that Tat exposure can lead to alterations of the BBB functions and decrease HAART efficacy in the CNS through overexpression of drug efflux transporters.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/biosynthesis
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- Acquired Immunodeficiency Syndrome/complications
- Acquired Immunodeficiency Syndrome/drug therapy
- Acquired Immunodeficiency Syndrome/genetics
- Acquired Immunodeficiency Syndrome/metabolism
- Animals
- Antiretroviral Therapy, Highly Active
- Astrocytes/cytology
- Astrocytes/metabolism
- Astrocytes/virology
- Blood-Brain Barrier/metabolism
- Blood-Brain Barrier/virology
- Cells, Cultured
- Central Nervous System Viral Diseases/drug therapy
- Central Nervous System Viral Diseases/etiology
- Central Nervous System Viral Diseases/genetics
- Central Nervous System Viral Diseases/metabolism
- Endothelial Cells/metabolism
- Endothelial Cells/virology
- Gene Products, tat/genetics
- Gene Products, tat/metabolism
- HIV-1/genetics
- HIV-1/metabolism
- Humans
- Male
- Mice
- Protein Biosynthesis/drug effects
- Protein Biosynthesis/genetics
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Up-Regulation/drug effects
- Up-Regulation/genetics
- tat Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- Kentaro Hayashi
- Department of Surgery, University of Kentucky, Lexington, Kentucky 40536, USA
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163
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Eldeen MB, Deshmane SL, Simbiri K, Khalili K, Amini S, Sawaya BE. MH2 domain of Smad3 reduces HIV-1 Tat-induction of cytokine secretion. J Neuroimmunol 2006; 176:174-80. [PMID: 16750572 DOI: 10.1016/j.jneuroim.2006.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Revised: 04/03/2006] [Accepted: 04/05/2006] [Indexed: 11/20/2022]
Abstract
HIV-1 infection of the central nervous system (CNS) is associated with dysregulation of several important cytokines and chemokines, which are involved in inflammatory process. Earlier studies ascribed a critical role for Tat, a potent viral transcription activator, in this process by enhancing the expression of several immunomodulators including TGFbeta and MCP-1. Investigation of signaling pathways which are controlled by these cytokines led to identification of MH2 domain of Smad3, the downstream activator of TGFbeta pathway, as a modulator of MCP-1 promoter activity. The level of MCP-1 is increased in AIDS patients with neurologic problems, through recruitment of inflammatory cells, which can contribute to neuropathogenesis of AIDS. Therefore, we attempted to investigate the effect of MH2 on expression of MCP-1 and other immunolmodulators in CNS cells. By employing an adenovirus expression vector, we demonstrated that MH2 can decrease the levels of Tat-induced activation of MCP-1 and several other cytokines and chemokines in astrocytic cells. In addition, we showed that MH2 significantly reduced the activity of cytokines produced by cultures of adenovirus-MH2 transduced cells as measured by the transmigration of human PBMC cells. Thus, MH2 domain of Smad3 is a potential agent that may be developed as an inhibitor for the cytokine-mediated inflammatory responses in the brain and may have the potential to prevent transmigration of HIV-1-infected monocytes across the blood brain barrier in AIDS patients.
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Affiliation(s)
- Mazen B Eldeen
- Department of Neuroscience and Center for Neurovirology, Temple University School of Medicine, 1900 North 12th Street, Philadelphia, PA 19122, United States
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164
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Ghafouri M, Amini S, Khalili K, Sawaya BE. HIV-1 associated dementia: symptoms and causes. Retrovirology 2006; 3:28. [PMID: 16712719 PMCID: PMC1513597 DOI: 10.1186/1742-4690-3-28] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2006] [Accepted: 05/19/2006] [Indexed: 11/18/2022] Open
Abstract
Despite the use of highly active antiretroviral therapy (HAART), neuronal cell death remains a problem that is frequently found in the brains of HIV-1-infected patients. HAART has successfully prevented many of the former end-stage complications of AIDS, however, with increased survival times, the prevalence of minor HIV-1 associated cognitive impairment appears to be rising among AIDS patients. Further, HIV-1 associated dementia (HAD) is still prevalent in treated patients as well as attenuated forms of HAD and CNS opportunistic disorders. HIV-associated cognitive impairment correlates with the increased presence in the CNS of activated, though not necessarily HIV-1-infected, microglia and CNS macrophages. This suggests that indirect mechanisms of neuronal injury and loss/death occur in HIV/AIDS as a basis for dementia since neurons are not themselves productively infected by HIV-1. In this review, we discussed the symptoms and causes leading to HAD. Outcome from this review will provide new information regarding mechanisms of neuronal loss in AIDS patients.
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Affiliation(s)
- Mohammad Ghafouri
- Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Pennsylvania 19122, USA
| | - Shohreh Amini
- Department of Biology, College of Science and Technology, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - Kamel Khalili
- Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Pennsylvania 19122, USA
| | - Bassel E Sawaya
- Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Pennsylvania 19122, USA
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165
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King JE, Eugenin EA, Buckner CM, Berman JW. HIV tat and neurotoxicity. Microbes Infect 2006; 8:1347-57. [PMID: 16697675 DOI: 10.1016/j.micinf.2005.11.014] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2005] [Accepted: 11/29/2005] [Indexed: 01/13/2023]
Abstract
HIV tat is the transactivator of HIV-1, supporting efficient viral replication by stabilizing the transcription of viral genes. Tat can be released from HIV-infected cells and alter several functions in uninfected cells. In the brain, tat induces neuronal dysfunction/toxicity, even though neurons cannot be directly infected with HIV, resulting in CNS pathology, such as the dementia and encephalitis associated with NeuroAIDS. This review discusses the most recent data addressing tat-induced neurotoxicity and integrates these new findings in the context of NeuroAIDS.
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Affiliation(s)
- J E King
- Department of Pathology, F727, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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