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DeMarino C, Cowen M, Williams A, Khatkar P, Abulwerdi FA, Henderson L, Denniss J, Pleet ML, Luttrell DR, Vaisman I, Liotta LA, Steiner J, Le Grice SFJ, Nath A, Kashanchi F. Autophagy Deregulation in HIV-1-Infected Cells Increases Extracellular Vesicle Release and Contributes to TLR3 Activation. Viruses 2024; 16:643. [PMID: 38675983 PMCID: PMC11054313 DOI: 10.3390/v16040643] [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: 10/31/2023] [Revised: 04/12/2024] [Accepted: 04/17/2024] [Indexed: 04/28/2024] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) infection can result in HIV-associated neurocognitive disorder (HAND), a spectrum of disorders characterized by neurological impairment and chronic inflammation. Combined antiretroviral therapy (cART) has elicited a marked reduction in the number of individuals diagnosed with HAND. However, there is continual, low-level viral transcription due to the lack of a transcription inhibitor in cART regimens, which results in the accumulation of viral products within infected cells. To alleviate stress, infected cells can release accumulated products, such as TAR RNA, in extracellular vesicles (EVs), which can contribute to pathogenesis in neighboring cells. Here, we demonstrate that cART can contribute to autophagy deregulation in infected cells and increased EV release. The impact of EVs released from HIV-1 infected myeloid cells was found to contribute to CNS pathogenesis, potentially through EV-mediated TLR3 (Toll-like receptor 3) activation, suggesting the need for therapeutics to target this mechanism. Three HIV-1 TAR-binding compounds, 103FA, 111FA, and Ral HCl, were identified that recognize TAR RNA and reduce TLR activation. These data indicate that packaging of viral products into EVs, potentially exacerbated by antiretroviral therapeutics, may induce chronic inflammation of the CNS observed in cART-treated patients, and novel therapeutic strategies may be exploited to mitigate morbidity.
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Affiliation(s)
- Catherine DeMarino
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Discovery Hall Room 182, 10900 University Blvd., Manassas, VA 20110, USA; (C.D.); (M.C.); (A.W.); (P.K.); (M.L.P.)
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA; (L.H.); (J.D.); (D.R.L.); (A.N.)
| | - Maria Cowen
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Discovery Hall Room 182, 10900 University Blvd., Manassas, VA 20110, USA; (C.D.); (M.C.); (A.W.); (P.K.); (M.L.P.)
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA; (L.H.); (J.D.); (D.R.L.); (A.N.)
| | - Anastasia Williams
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Discovery Hall Room 182, 10900 University Blvd., Manassas, VA 20110, USA; (C.D.); (M.C.); (A.W.); (P.K.); (M.L.P.)
| | - Pooja Khatkar
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Discovery Hall Room 182, 10900 University Blvd., Manassas, VA 20110, USA; (C.D.); (M.C.); (A.W.); (P.K.); (M.L.P.)
| | - Fardokht A. Abulwerdi
- Basic Research Laboratory, National Cancer Institute, Frederick, MD 21702, USA; (F.A.A.); (S.F.J.L.G.)
| | - Lisa Henderson
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA; (L.H.); (J.D.); (D.R.L.); (A.N.)
| | - Julia Denniss
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA; (L.H.); (J.D.); (D.R.L.); (A.N.)
| | - Michelle L. Pleet
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Discovery Hall Room 182, 10900 University Blvd., Manassas, VA 20110, USA; (C.D.); (M.C.); (A.W.); (P.K.); (M.L.P.)
| | - Delores R. Luttrell
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA; (L.H.); (J.D.); (D.R.L.); (A.N.)
| | - Iosif Vaisman
- Laboratory for Structural Bioinformatics, School of Systems Biology, George Mason University, Manassas, VA 20110, USA;
| | - Lance A. Liotta
- Center for Applied Proteomics and Molecular Medicine, George Mason University, Manassas, VA 20110, USA;
| | - Joseph Steiner
- Translational Neuroscience Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA;
| | - Stuart F. J. Le Grice
- Basic Research Laboratory, National Cancer Institute, Frederick, MD 21702, USA; (F.A.A.); (S.F.J.L.G.)
| | - Avindra Nath
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA; (L.H.); (J.D.); (D.R.L.); (A.N.)
| | - Fatah Kashanchi
- Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Discovery Hall Room 182, 10900 University Blvd., Manassas, VA 20110, USA; (C.D.); (M.C.); (A.W.); (P.K.); (M.L.P.)
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Kozsurek M, Király K, Gyimesi K, Lukácsi E, Fekete C, Gereben B, Mohácsik P, Helyes Z, Bölcskei K, Tékus V, Pap K, Szűcs E, Benyhe S, Imre T, Szabó P, Gajtkó A, Holló K, Puskár Z. Unique, Specific CART Receptor-Independent Regulatory Mechanism of CART(55-102) Peptide in Spinal Nociceptive Transmission and Its Relation to Dipeptidyl-Peptidase 4 (DDP4). Int J Mol Sci 2023; 24:ijms24020918. [PMID: 36674439 PMCID: PMC9865214 DOI: 10.3390/ijms24020918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 12/09/2022] [Accepted: 12/14/2022] [Indexed: 01/06/2023] Open
Abstract
Cocaine- and amphetamine-regulated transcript (CART) peptides are involved in several physiological and pathological processes, but their mechanism of action is unrevealed due to the lack of identified receptor(s). We provided evidence for the antihyperalgesic effect of CART(55-102) by inhibiting dipeptidyl-peptidase 4 (DPP4) in astrocytes and consequently reducing neuroinflammation in the rat spinal dorsal horn in a carrageenan-evoked inflammation model. Both naturally occurring CART(55-102) and CART(62-102) peptides are present in the spinal cord. CART(55-102) is not involved in acute nociception but regulates spinal pain transmission during peripheral inflammation. While the full-length peptide with a globular motif contributes to hyperalgesia, its N-terminal inhibits this process. Although the anti-hyperalgesic effects of CART(55-102), CART(55-76), and CART(62-76) are blocked by opioid receptor antagonists in our inflammatory models, but not in neuropathic Seltzer model, none of them bind to any opioid or G-protein coupled receptors. DPP4 interacts with Toll-like receptor 4 (TLR4) signalling in spinal astrocytes and enhances the TLR4-induced expression of interleukin-6 and tumour necrosis factor alpha contributing to inflammatory pain. Depending on the state of inflammation, CART(55-102) is processed in the spinal cord, resulting in the generation of biologically active isoleucine-proline-isoleucine (IPI) tripeptide, which inhibits DPP4, leading to significantly decreased glia-derived cytokine production and hyperalgesia.
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Affiliation(s)
- Márk Kozsurek
- Department of Anatomy, Histology and Embryology, Semmelweis University, H-1094 Budapest, Hungary
| | - Kornél Király
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary
| | - Klára Gyimesi
- Department of Anatomy, Histology and Embryology, Semmelweis University, H-1094 Budapest, Hungary
- Department of Anaesthesiology, Uzsoki Hospital, H-1145 Budapest, Hungary
| | - Erika Lukácsi
- Department of Anatomy, Histology and Embryology, Semmelweis University, H-1094 Budapest, Hungary
| | - Csaba Fekete
- Laboratory of Integrative Neuroendocrinology, Institute of Experimental Medicine, Eötvös Loránd Research Network, H-1083 Budapest, Hungary
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, MA 02111, USA
| | - Balázs Gereben
- Laboratory of Integrative Neuroendocrinology, Institute of Experimental Medicine, Eötvös Loránd Research Network, H-1083 Budapest, Hungary
| | - Petra Mohácsik
- Laboratory of Integrative Neuroendocrinology, Institute of Experimental Medicine, Eötvös Loránd Research Network, H-1083 Budapest, Hungary
| | - Zsuzsanna Helyes
- Department of Pharmacology and Pharmacotherapy, University of Pécs, H-7624 Pécs, Hungary
- National Laboratory for Drug Research and Development, H-1117 Budapest, Hungary
- Chronic Pain Research Group, Eötvös Loránd Research Network, H-7624 Pécs, Hungary
| | - Kata Bölcskei
- Department of Pharmacology and Pharmacotherapy, University of Pécs, H-7624 Pécs, Hungary
| | - Valéria Tékus
- Department of Pharmacology and Pharmacotherapy, University of Pécs, H-7624 Pécs, Hungary
- National Laboratory for Drug Research and Development, H-1117 Budapest, Hungary
| | - Károly Pap
- Department of Orthopaedics and Traumatology, Uzsoki Hospital, H-1145 Budapest, Hungary
| | - Edina Szűcs
- Institute of Biochemistry, Biological Research Centre, Eötvös Loránd Research Network, H-6726 Szeged, Hungary
| | - Sándor Benyhe
- Institute of Biochemistry, Biological Research Centre, Eötvös Loránd Research Network, H-6726 Szeged, Hungary
| | - Tímea Imre
- MS Metabolomics Laboratory, Instrumentation Centre, Research Centre for Natural Sciences, Eötvös Loránd Research Network, H-1117 Budapest, Hungary
| | - Pál Szabó
- MS Metabolomics Laboratory, Instrumentation Centre, Research Centre for Natural Sciences, Eötvös Loránd Research Network, H-1117 Budapest, Hungary
| | - Andrea Gajtkó
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - Krisztina Holló
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - Zita Puskár
- Department of Anatomy, Histology and Embryology, Semmelweis University, H-1094 Budapest, Hungary
- Correspondence:
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Chavarría C, Ivagnes R, Souza JM. Extracellular Alpha-Synuclein: Mechanisms for Glial Cell Internalization and Activation. Biomolecules 2022; 12:biom12050655. [PMID: 35625583 PMCID: PMC9138387 DOI: 10.3390/biom12050655] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/22/2022] [Accepted: 04/27/2022] [Indexed: 11/16/2022] Open
Abstract
Alpha-synuclein (α-syn) is a small protein composed of 140 amino acids and belongs to the group of intrinsically disordered proteins. It is a soluble protein that is highly expressed in neurons and expressed at low levels in glial cells. The monomeric protein aggregation process induces the formation of oligomeric intermediates and proceeds towards fibrillar species. These α-syn conformational species have been detected in the extracellular space and mediate consequences on surrounding neurons and glial cells. In particular, higher-ordered α-syn aggregates are involved in microglial and oligodendrocyte activation, as well as in the induction of astrogliosis. These phenomena lead to mitochondrial dysfunction, reactive oxygen and nitrogen species formation, and the induction of an inflammatory response, associated with neuronal cell death. Several receptors participate in cell activation and/or in the uptake of α-syn, which can vary depending on the α-syn aggregated state and cell types. The receptors involved in this process are of outstanding relevance because they may constitute potential therapeutic targets for the treatment of PD and related synucleinopathies. This review article focuses on the mechanism associated with extracellular α-syn uptake in glial cells and the consequent glial cell activation that contributes to the neuronal death associated with synucleinopathies.
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Extracellular Cardiolipin Modulates Select Immune Functions of Astrocytes in Toll-Like Receptor (TLR) 4-Dependent Manner. Mediators Inflamm 2022; 2022:9946439. [PMID: 35369030 PMCID: PMC8975658 DOI: 10.1155/2022/9946439] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 01/11/2022] [Accepted: 02/16/2022] [Indexed: 12/23/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by chronic neuroinflammation, which is partially mediated by dysregulated functions of glial cells. Cardiolipin (CL) is a phospholipid normally confined to the inner mitochondrial membrane; however, it has been detected in human sera, indicating that it can exist in the extracellular space where it may interact with nearby cells. Although CL has been shown to modulate several functions of microglia in a toll-like receptor (TLR) 4-dependent manner, the effects of extracellular CL on astrocytes are unknown. In addition to their homeostatic functions, astrocytes participate in neuroimmune responses of the brain and express TLR 4. Therefore, we hypothesized that extracellular CL (1) modulates the secretion of cytokines and cytotoxins by astrocytes, as well as their phagocytic activity, and (2) acts by interacting with astrocyte TLR 4. We demonstrate that CL inhibits the lipopolysaccharide- (LPS-) induced secretion of cytotoxins and expression of glial fibrillary acidic protein (GFAP) by human U118 MG astrocytic cells. CL alone upregulates the phagocytic activity of human astrocytic cells and primary murine astrocytes. CL in combination with LPS upregulates secretion of interleukin (IL)-1β by astrocytic cells. Furthermore, CL alone increases the secretion of monocyte chemoattractant protein (MCP)-1 by astrocytic cells, which is blocked by the TLR 4-specific antagonist TAK-242. We demonstrate that CL upregulates MCP-1 secretion in the absence of its natural carrier protein, β2-glycoprotein 1, indicating that CL may be bioactive in the brain where this protein is not present. Lastly, we show that CL downregulates the expression of astrocytic TLR 4, implying that CL engages this receptor, as its activation has been shown to lead to its degradation. Overall, our study extends the list of cell type functions of which CL modulates and provides evidence that CL, or liposomes containing this phospholipid can be used to modulate specific neuroimmune functions of astrocytes.
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Converging purinergic and immune signaling pathways drive IL-6 secretion by Fragile X cortical astrocytes via STAT3. J Neuroimmunol 2021; 361:577745. [PMID: 34695768 DOI: 10.1016/j.jneuroim.2021.577745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 09/10/2021] [Accepted: 10/06/2021] [Indexed: 11/21/2022]
Abstract
The symptoms of Fragile X syndrome (FXS) are driven in part by abnormal glial-mediated function. FXS astrocytes release elevated levels of immune-related factors interleukin-6 (IL-6) and tenascin C (TNC), and also demonstrate increased purinergic signaling, a pathway linked to signaling factor release. Here, in cortical astrocytes from the Fmr1 knockout (KO) FXS mouse model, purinergic agonism enhanced TNC secretion and STAT3 phosphorylation, two processes linked to elevated IL-6 secretion in FXS, while STAT3 knockdown and TLR4 antagonism normalized Fmr1 KO IL-6 release. We therefore suggest that purinergic signaling and immune regulatory pathways converge to drive FXS cortical pro-inflammatory responses.
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6
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Islam B, Stephenson J, Young B, Manca M, Buckley DA, Radford H, Zis P, Johnson MI, Finn DP, McHugh PC. The Identification of Blood Biomarkers of Chronic Neuropathic Pain by Comparative Transcriptomics. Neuromolecular Med 2021; 24:320-338. [PMID: 34741226 PMCID: PMC9402512 DOI: 10.1007/s12017-021-08694-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 10/14/2021] [Indexed: 12/16/2022]
Abstract
In this study, we recruited 50 chronic pain (neuropathic and nociceptive) and 43 pain-free controls to identify specific blood biomarkers of chronic neuropathic pain (CNP). Affymetrix microarray was carried out on a subset of samples selected 10 CNP and 10 pain-free control participants. The most significant genes were cross-validated using the entire dataset by quantitative real-time PCR (qRT-PCR). In comparative analysis of controls and CNP patients, WLS (P = 4.80 × 10–7), CHPT1 (P = 7.74 × 10–7) and CASP5 (P = 2.30 × 10–5) were highly significant, whilst FGFBP2 (P = 0.00162), STAT1 (P = 0.00223), FCRL6 (P = 0.00335), MYC (P = 0.00335), XCL2 (P = 0.0144) and GZMA (P = 0.0168) were significant in all CNP patients. A three-arm comparative analysis was also carried out with control as the reference group and CNP samples differentiated into two groups of high and low S-LANSS score using a cut-off of 12. STAT1, XCL2 and GZMA were not significant but KIR3DL2 (P = 0.00838), SH2D1B (P = 0.00295) and CXCR31 (P = 0.0136) were significant in CNP high S-LANSS group (S-LANSS score > 12), along with WLS (P = 8.40 × 10–5), CHPT1 (P = 7.89 × 10–4), CASP5 (P = 0.00393), FGFBP2 (P = 8.70 × 10–4) and FCRL6 (P = 0.00199), suggesting involvement of immune pathways in CNP mechanisms. None of the genes was significant in CNP samples with low (< 12) S-LANSS score. The area under the receiver operating characteristic (AUROC) analysis showed that combination of MYC, STAT1, TLR4, CASP5 and WLS gene expression could be potentially used as a biomarker signature of CNP (AUROC − 0.852, (0.773, 0.931 95% CI)).
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Affiliation(s)
- Barira Islam
- Centre for Biomarker Research, University of Huddersfield, Huddersfield, HD1 3DH, UK.,School of Applied Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK
| | - John Stephenson
- Centre for Biomarker Research, University of Huddersfield, Huddersfield, HD1 3DH, UK.,School of Human and Health Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK
| | - Bethan Young
- Centre for Biomarker Research, University of Huddersfield, Huddersfield, HD1 3DH, UK.,School of Applied Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK
| | - Maurizio Manca
- Centre for Biomarker Research, University of Huddersfield, Huddersfield, HD1 3DH, UK.,School of Applied Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK
| | - David A Buckley
- Centre for Biomarker Research, University of Huddersfield, Huddersfield, HD1 3DH, UK.,School of Applied Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK
| | | | | | - Mark I Johnson
- Centre for Pain Research, School of Clinical and Applied Sciences, Leeds Beckett University, Leeds, LS1 3HE, UK
| | - David P Finn
- Pharmacology & Therapeutics, School of Medicine, Galway, Neuroscience Centre and Centre for Pain Research, National University of Ireland Galway, University Road, Galway, Ireland
| | - Patrick C McHugh
- Centre for Biomarker Research, University of Huddersfield, Huddersfield, HD1 3DH, UK. .,School of Applied Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK.
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7
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HIV-Proteins-Associated CNS Neurotoxicity, Their Mediators, and Alternative Treatments. Cell Mol Neurobiol 2021; 42:2553-2569. [PMID: 34562223 DOI: 10.1007/s10571-021-01151-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 09/19/2021] [Indexed: 02/08/2023]
Abstract
Human immunodeficiency virus (HIV)-infected people's livelihoods are gradually being prolonged with the use of combined antiretroviral therapy (ART). Conversely, despite viral suppression by ART, the symptoms of HIV-associated neurocognitive disorder (HAND) endure. HAND persists because ART cannot really permanently confiscate the virus from the body. HAND encompasses a variety of conditions based on clinical presentation and severity level, comprising asymptomatic neurocognitive impairment, moderate neurocognitive disorder, and HIV-associated dementia. During the early stages of HIV infection, inflammation compromises the blood-brain barrier, allowing toxic virus, infected monocytes, macrophages, T-lymphocytes, and cellular products from the bloodstream to enter the brain and eventually the entire central nervous system. Since there are no resident T-lymphocytes in the brain, the virus will live for decades in macrophages and astrocytes, establishing a reservoir of infection. The HIV proteins then inflame neurons both directly and indirectly. The purpose of this review is to provide a synopsis of the effects of these proteins on the central nervous system and conceptualize avenues to be considered in mitigating HAND. We used bioinformatics repositories extensively to simulate the transcription factors that bind to the promoter of the HIV-1 protein and possibly could be used as a target to circumvent HIV-associated neurocognitive disorders. In the same vein, a protein-protein interaction complex was also deduced from a Search Tool for the Retrieval of Interacting Genes. In conclusion, this provides an alternative strategy that could be used to avert HAND.
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League AF, Gorman BL, Hermes DJ, Johnson CT, Jacobs IR, Yadav-Samudrala BJ, Poklis JL, Niphakis MJ, Cravatt BF, Lichtman AH, Ignatowska-Jankowska BM, Fitting S. Monoacylglycerol Lipase Inhibitor MJN110 Reduces Neuronal Hyperexcitability, Restores Dendritic Arborization Complexity, and Regulates Reward-Related Behavior in Presence of HIV-1 Tat. Front Neurol 2021; 12:651272. [PMID: 34484091 PMCID: PMC8415271 DOI: 10.3389/fneur.2021.651272] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 07/12/2021] [Indexed: 12/01/2022] Open
Abstract
While current therapeutic strategies for people living with human immunodeficiency virus type 1 (HIV-1) suppress virus replication peripherally, viral proteins such as transactivator of transcription (Tat) enter the central nervous system early upon infection and contribute to chronic inflammatory conditions even alongside antiretroviral treatment. As demand grows for supplemental strategies to combat virus-associated pathology presenting frequently as HIV-associated neurocognitive disorders (HAND), the present study aimed to characterize the potential utility of inhibiting monoacylglycerol lipase (MAGL) activity to increase inhibitory activity at cannabinoid receptor-type 1 receptors through upregulation of 2-arachidonoylglycerol (2-AG) and downregulation of its degradation into proinflammatory metabolite arachidonic acid (AA). The MAGL inhibitor MJN110 significantly reduced intracellular calcium and increased dendritic branching complexity in Tat-treated primary frontal cortex neuron cultures. Chronic MJN110 administration in vivo increased 2-AG levels in the prefrontal cortex (PFC) and striatum across Tat(+) and Tat(–) groups and restored PFC N-arachidonoylethanolamine (AEA) levels in Tat(+) subjects. While Tat expression significantly increased rate of reward-related behavioral task acquisition in a novel discriminative stimulus learning and cognitive flexibility assay, MJN110 altered reversal acquisition specifically in Tat(+) mice to rates indistinguishable from Tat(–) controls. Collectively, our results suggest a neuroprotective role of MAGL inhibition in reducing neuronal hyperexcitability, restoring dendritic arborization complexity, and mitigating neurocognitive alterations driven by viral proteins associated with latent HIV-1 infection.
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Affiliation(s)
- Alexis F League
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
| | - Benjamin L Gorman
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
| | - Douglas J Hermes
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
| | - Clare T Johnson
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
| | - Ian R Jacobs
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
| | - Barkha J Yadav-Samudrala
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
| | - Justin L Poklis
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | - Micah J Niphakis
- Department of Chemistry, Scripps Research Institute, La Jolla, CA, United States
| | - Benjamin F Cravatt
- Department of Chemistry, Scripps Research Institute, La Jolla, CA, United States
| | - Aron H Lichtman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | | | - Sylvia Fitting
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
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9
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Nickoloff-Bybel EA, Festa L, Meucci O, Gaskill PJ. Co-receptor signaling in the pathogenesis of neuroHIV. Retrovirology 2021; 18:24. [PMID: 34429135 PMCID: PMC8385912 DOI: 10.1186/s12977-021-00569-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 08/11/2021] [Indexed: 12/13/2022] Open
Abstract
The HIV co-receptors, CCR5 and CXCR4, are necessary for HIV entry into target cells, interacting with the HIV envelope protein, gp120, to initiate several signaling cascades thought to be important to the entry process. Co-receptor signaling may also promote the development of neuroHIV by contributing to both persistent neuroinflammation and indirect neurotoxicity. But despite the critical importance of CXCR4 and CCR5 signaling to HIV pathogenesis, there is only one therapeutic (the CCR5 inhibitor Maraviroc) that targets these receptors. Moreover, our understanding of co-receptor signaling in the specific context of neuroHIV is relatively poor. Research into co-receptor signaling has largely stalled in the past decade, possibly owing to the complexity of the signaling cascades and functions mediated by these receptors. Examining the many signaling pathways triggered by co-receptor activation has been challenging due to the lack of specific molecular tools targeting many of the proteins involved in these pathways and the wide array of model systems used across these experiments. Studies examining the impact of co-receptor signaling on HIV neuropathogenesis often show activation of multiple overlapping pathways by similar stimuli, leading to contradictory data on the effects of co-receptor activation. To address this, we will broadly review HIV infection and neuropathogenesis, examine different co-receptor mediated signaling pathways and functions, then discuss the HIV mediated signaling and the differences between activation induced by HIV and cognate ligands. We will assess the specific effects of co-receptor activation on neuropathogenesis, focusing on neuroinflammation. We will also explore how the use of substances of abuse, which are highly prevalent in people living with HIV, can exacerbate the neuropathogenic effects of co-receptor signaling. Finally, we will discuss the current state of therapeutics targeting co-receptors, highlighting challenges the field has faced and areas in which research into co-receptor signaling would yield the most therapeutic benefit in the context of HIV infection. This discussion will provide a comprehensive overview of what is known and what remains to be explored in regard to co-receptor signaling and HIV infection, and will emphasize the potential value of HIV co-receptors as a target for future therapeutic development. ![]()
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Affiliation(s)
- E A Nickoloff-Bybel
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - L Festa
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, 240 S. 40th Street, Philadelphia, PA, 19104, USA
| | - O Meucci
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.,Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, 19102, USA
| | - P J Gaskill
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.
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Assis MA, Carranza PG, Ambrosio E. A "Drug-Dependent" Immune System Can Compromise Protection against Infection: The Relationships between Psychostimulants and HIV. Viruses 2021; 13:v13050722. [PMID: 33919273 PMCID: PMC8143316 DOI: 10.3390/v13050722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/14/2021] [Accepted: 04/19/2021] [Indexed: 01/31/2023] Open
Abstract
Psychostimulant use is a major comorbidity in people living with HIV, which was initially explained by them adopting risky behaviors that facilitate HIV transmission. However, the effects of drug use on the immune system might also influence this phenomenon. Psychostimulants act on peripheral immune cells even before they reach the central nervous system (CNS) and their effects on immunity are likely to influence HIV infection. Beyond their canonical activities, classic neurotransmitters and neuromodulators are expressed by peripheral immune cells (e.g., dopamine and enkephalins), which display immunomodulatory properties and could be influenced by psychostimulants. Immune receptors, like Toll-like receptors (TLRs) on microglia, are modulated by cocaine and amphetamine exposure. Since peripheral immunocytes also express TLRs, they may be similarly affected by psychostimulants. In this review, we will summarize how psychostimulants are currently thought to influence peripheral immunity, mainly focusing on catecholamines, enkephalins and TLR4, and shed light on how these drugs might affect HIV infection. We will try to shift from the classic CNS perspective and adopt a more holistic view, addressing the potential impact of psychostimulants on the peripheral immune system and how their systemic effects could influence HIV infection.
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Affiliation(s)
- María Amparo Assis
- Facultad de Ciencias Médicas, Universidad Nacional de Santiago del Estero (UNSE), Santiago del Estero G4200, Argentina;
- Laboratorio de Biología Molecular, Inmunología y Microbiología, Instituto Multidisciplinario de Salud, Tecnología y Desarrollo (IMSaTeD), CONICET-UNSE, Santiago del Estero G4206, Argentina
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain;
- Correspondence:
| | - Pedro Gabriel Carranza
- Facultad de Ciencias Médicas, Universidad Nacional de Santiago del Estero (UNSE), Santiago del Estero G4200, Argentina;
- Laboratorio de Biología Molecular, Inmunología y Microbiología, Instituto Multidisciplinario de Salud, Tecnología y Desarrollo (IMSaTeD), CONICET-UNSE, Santiago del Estero G4206, Argentina
- Facultad de Agronomía y Agroindustrias, Universidad Nacional de Santiago del Estero, Santiago del Estero G4206, Argentina
| | - Emilio Ambrosio
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), 28040 Madrid, Spain;
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11
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Wang S, Guan Y, Li T. The Potential Therapeutic Role of the HMGB1-TLR Pathway in Epilepsy. Curr Drug Targets 2021; 22:171-182. [PMID: 32729417 DOI: 10.2174/1389450121999200729150443] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 02/08/2023]
Abstract
Epilepsy is one of the most common serious neurological disorders, affecting over 70 million people worldwide. For the treatment of epilepsy, antiepileptic drugs (AEDs) and surgeries are widely used. However, drug resistance and adverse effects indicate the need to develop targeted AEDs based on further exploration of the epileptogenic mechanism. Currently, many efforts have been made to elucidate the neuroinflammation theory in epileptogenesis, which may show potential in the treatment of epilepsy. In this respect, an important target protein, high mobility group box 1 (HMGB1), has received increased attention and has been developed rapidly. HMGB1 is expressed in various eukaryotic cells and localized in the cell nucleus. When HMGB1 is released by injuries or diseases, it participates in inflammation. Recent studies suggest that HMGB1 via Toll-like receptor (TLR) pathways can trigger inflammatory responses and play an important role in epilepsy. In addition, studies of HMGB1 have shown its potential in the treatment of epilepsy. Herein, the authors analyzed the experimental and clinical evidence of the HMGB1-TLR pathway in epilepsy to summarize the theory of epileptogenesis and provide insights into antiepileptic therapy in this novel field.
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Affiliation(s)
- Shu Wang
- Department of Neurosurgery, SanBo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Yuguang Guan
- Department of Neurosurgery, SanBo Brain Hospital, Capital Medical University, Beijing 100093, China
| | - Tianfu Li
- Department of Neurology, SanBo Brain Hospital, Capital Medical University, Beijing 100093, China
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12
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Li L, Acioglu C, Heary RF, Elkabes S. Role of astroglial toll-like receptors (TLRs) in central nervous system infections, injury and neurodegenerative diseases. Brain Behav Immun 2021; 91:740-755. [PMID: 33039660 PMCID: PMC7543714 DOI: 10.1016/j.bbi.2020.10.007] [Citation(s) in RCA: 132] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/22/2020] [Accepted: 10/06/2020] [Indexed: 02/07/2023] Open
Abstract
Central nervous system (CNS) innate immunity plays essential roles in infections, neurodegenerative diseases, and brain or spinal cord injuries. Astrocytes and microglia are the principal cells that mediate innate immunity in the CNS. Pattern recognition receptors (PRRs), expressed by astrocytes and microglia, sense pathogen-derived or endogenous ligands released by damaged cells and initiate the innate immune response. Toll-like receptors (TLRs) are a well-characterized family of PRRs. The contribution of microglial TLR signaling to CNS pathology has been extensively investigated. Even though astrocytes assume a wide variety of key functions, information about the role of astroglial TLRs in CNS disease and injuries is limited. Because astrocytes display heterogeneity and exhibit phenotypic plasticity depending on the effectors present in the local milieu, they can exert both detrimental and beneficial effects. TLRs are modulators of these paradoxical astroglial properties. The goal of the current review is to highlight the essential roles played by astroglial TLRs in CNS infections, injuries and diseases. We discuss the contribution of astroglial TLRs to host defense as well as the dissemination of viral and bacterial infections in the CNS. We examine the link between astroglial TLRs and the pathogenesis of neurodegenerative diseases and present evidence showing the pivotal influence of astroglial TLR signaling on sterile inflammation in CNS injury. Finally, we define the research questions and areas that warrant further investigations in the context of astrocytes, TLRs, and CNS dysfunction.
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Affiliation(s)
- Lun Li
- The Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States
| | - Cigdem Acioglu
- The Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States
| | - Robert F. Heary
- Department of Neurological Surgery, Hackensack Meridian School of Medicine, Nutley, NJ 07110, United States
| | - Stella Elkabes
- The Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States.
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13
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Jha NK, Sharma A, Jha SK, Ojha S, Chellappan DK, Gupta G, Kesari KK, Bhardwaj S, Shukla SD, Tambuwala MM, Ruokolainen J, Dua K, Singh SK. Alzheimer's disease-like perturbations in HIV-mediated neuronal dysfunctions: understanding mechanisms and developing therapeutic strategies. Open Biol 2020; 10:200286. [PMID: 33352062 PMCID: PMC7776571 DOI: 10.1098/rsob.200286] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 11/27/2020] [Indexed: 01/10/2023] Open
Abstract
Excessive exposure to toxic substances or chemicals in the environment and various pathogens, including viruses and bacteria, is associated with the onset of numerous brain abnormalities. Among them, pathogens, specifically viruses, elicit persistent inflammation that plays a major role in Alzheimer's disease (AD) as well as dementia. AD is the most common brain disorder that affects thought, speech, memory and ability to execute daily routines. It is also manifested by progressive synaptic impairment and neurodegeneration, which eventually leads to dementia following the accumulation of Aβ and hyperphosphorylated Tau. Numerous factors contribute to the pathogenesis of AD, including neuroinflammation associated with pathogens, and specifically viruses. The human immunodeficiency virus (HIV) is often linked with HIV-associated neurocognitive disorders (HAND) following permeation through the blood-brain barrier (BBB) and induction of persistent neuroinflammation. Further, HIV infections also exhibited the ability to modulate numerous AD-associated factors such as BBB regulators, members of stress-related pathways as well as the amyloid and Tau pathways that lead to the formation of amyloid plaques or neurofibrillary tangles accumulation. Studies regarding the role of HIV in HAND and AD are still in infancy, and potential link or mechanism between both is not yet established. Thus, in the present article, we attempt to discuss various molecular mechanisms that contribute to the basic understanding of the role of HIV-associated neuroinflammation in AD and HAND. Further, using numerous growth factors and drugs, we also present possible therapeutic strategies to curb the neuroinflammatory changes and its associated sequels.
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Affiliation(s)
- Niraj Kumar Jha
- Department of Biotechnology, School of Engineering and Technology (SET), Sharda University, Greater Noida, UP 201310, India
| | - Ankur Sharma
- Department of Life Science, School of Basic Science and Research (SBSR), Sharda University, Greater Noida, UP 201310, India
| | - Saurabh Kumar Jha
- Department of Biotechnology, School of Engineering and Technology (SET), Sharda University, Greater Noida, UP 201310, India
| | - Shreesh Ojha
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, PO Box 17666, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Dinesh Kumar Chellappan
- Department of Life Sciences, School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur 57000, Malaysia
| | - Gaurav Gupta
- School of Phamacy, Suresh Gyan Vihar University, Jagatpura, Mahal Road, Jaipur, India
| | - Kavindra Kumar Kesari
- Department of Applied Physics, School of Science, Aalto University, Espoo 00076, Finland
| | - Shanu Bhardwaj
- Department of Biotechnology, HIMT, Greater Noida, CCS University, UP, India
| | - Shakti D. Shukla
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute (HMRI) and School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Murtaza M. Tambuwala
- School of Pharmacy and Pharmaceutical Sciences, Ulster University, Coleraine, County Londonderry, BT52 1SA, UK
| | - Janne Ruokolainen
- Department of Applied Physics, School of Science, Aalto University, Espoo 00076, Finland
| | - Kamal Dua
- Priority Research Centre for Healthy Lungs, Hunter Medical Research Institute (HMRI) and School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW 2308, Australia
- Discipline of Pharmacy, Graduate School of Health, University of Technology Sydney, Sydney, New South Wales 2007, Australia
- School of Pharmaceutical Sciences, Shoolini University of Biotechnology and Management Sciences, PO Box 9, Solan, Himachal Pradesh 173229, India
| | - Sandeep Kumar Singh
- Department of Biomedical Research, Centre of Biomedical Research, SGPGI Campus, Lucknow 226014, UP, India
- Biological Science, Indian Scientific Education and Technology Foundation, Lucknow 226002, UP, India
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14
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Marino J, Maubert ME, Mele AR, Spector C, Wigdahl B, Nonnemacher MR. Functional impact of HIV-1 Tat on cells of the CNS and its role in HAND. Cell Mol Life Sci 2020; 77:5079-5099. [PMID: 32577796 PMCID: PMC7674201 DOI: 10.1007/s00018-020-03561-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/08/2020] [Accepted: 05/25/2020] [Indexed: 02/07/2023]
Abstract
Human immunodeficiency virus type 1 (HIV-1) transactivator of transcription (Tat) is a potent mediator involved in the development of HIV-1-associated neurocognitive disorders (HAND). Tat is expressed even in the presence of antiretroviral therapy (ART) and is able to enter the central nervous system (CNS) through a variety of ways, where Tat can interact with microglia, astrocytes, brain microvascular endothelial cells, and neurons. The presence of low concentrations of extracellular Tat alone has been shown to lead to dysregulated gene expression, chronic cell activation, inflammation, neurotoxicity, and structural damage in the brain. The reported effects of Tat are dependent in part on the specific HIV-1 subtype and amino acid length of Tat used. HIV-1 subtype B Tat is the most common subtype in North American and therefore, most studies have been focused on subtype B Tat; however, studies have shown many genetic, biologic, and pathologic differences between HIV subtype B and subtype C Tat. This review will focus primarily on subtype B Tat where the full-length protein is 101 amino acids, but will also consider variants of Tat, such as Tat 72 and Tat 86, that have been reported to exhibit a number of distinctive activities with respect to mediating CNS damage and neurotoxicity.
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Affiliation(s)
- Jamie Marino
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th St, Philadelphia, PA, 19102, USA
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Monique E Maubert
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th St, Philadelphia, PA, 19102, USA
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Anthony R Mele
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th St, Philadelphia, PA, 19102, USA
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Cassandra Spector
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th St, Philadelphia, PA, 19102, USA
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th St, Philadelphia, PA, 19102, USA
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
- Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Michael R Nonnemacher
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th St, Philadelphia, PA, 19102, USA.
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA.
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15
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Opioid and neuroHIV Comorbidity - Current and Future Perspectives. J Neuroimmune Pharmacol 2020; 15:584-627. [PMID: 32876803 PMCID: PMC7463108 DOI: 10.1007/s11481-020-09941-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 07/02/2020] [Indexed: 12/14/2022]
Abstract
With the current national opioid crisis, it is critical to examine the mechanisms underlying pathophysiologic interactions between human immunodeficiency virus (HIV) and opioids in the central nervous system (CNS). Recent advances in experimental models, methodology, and our understanding of disease processes at the molecular and cellular levels reveal opioid-HIV interactions with increasing clarity. However, despite the substantial new insight, the unique impact of opioids on the severity, progression, and prognosis of neuroHIV and HIV-associated neurocognitive disorders (HAND) are not fully understood. In this review, we explore, in detail, what is currently known about mechanisms underlying opioid interactions with HIV, with emphasis on individual HIV-1-expressed gene products at the molecular, cellular and systems levels. Furthermore, we review preclinical and clinical studies with a focus on key considerations when addressing questions of whether opioid-HIV interactive pathogenesis results in unique structural or functional deficits not seen with either disease alone. These considerations include, understanding the combined consequences of HIV-1 genetic variants, host variants, and μ-opioid receptor (MOR) and HIV chemokine co-receptor interactions on the comorbidity. Lastly, we present topics that need to be considered in the future to better understand the unique contributions of opioids to the pathophysiology of neuroHIV. Blood-brain barrier and the neurovascular unit. With HIV and opiate co-exposure (represented below the dotted line), there is breakdown of tight junction proteins and increased leakage of paracellular compounds into the brain. Despite this, opiate exposure selectively increases the expression of some efflux transporters, thereby restricting brain penetration of specific drugs. ![]()
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16
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Halder A, Yadav K, Aggarwal A, Singhal N, Sandhir R. Activation of TNFR1 and TLR4 following oxygen glucose deprivation promotes mitochondrial fission in C6 astroglial cells. Cell Signal 2020; 75:109714. [PMID: 32693013 DOI: 10.1016/j.cellsig.2020.109714] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 06/30/2020] [Accepted: 07/12/2020] [Indexed: 12/14/2022]
Abstract
Astrocytes have emerged as active players in the innate immune response triggered by various types of insults. Recent literature suggests that mitochondria are key participants in innate immunity. The present study investigates the role of ischemia-induced innate immune response on p65/PGC-1α mediated mitochondrial dynamics in C6 astroglial cells. OGD conditions induced astroglial differentiation in C6 cells and increased the expression of hypoxia markers; HIF-1α, HO-1 and Cox4i2. OGD conditions resulted in induction of innate immune response in terms of expression of TNFR1 and TLR4 along with increase in IL-6 and TNF-α levels. OGD conditions resulted in decreased expression of I-κB with a concomitant increase in phos-p65 levels. The expression of PGC-1α, a key regulator of mitochondrial biogenesis, was also increased. Immunochemical staining suggested that phos-p65 and PGC-1α was co-localized. Studies on mitochondrial fusion (Mfn-1) and fission (DRP1) markers revealed shift toward fission. In addition, mitochondrial membrane potential decreased with increased DNA degradation and apoptosis confirming mitochondrial fission under OGD conditions. However, inhibition of phos-p65 by MG132 reduced the co-localization of phos-p65/ PGC-1α and significantly increased the Mfn-1 expression. The findings demonstrate the involvement of TNFR1 and TLR4 mediated immune response followed by interaction between phos-p65 and PGC-1α in promoting fission in C6 cells under hypoxic condition.
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Affiliation(s)
- Avishek Halder
- Department of Biochemistry, Basic Medical Science Block II, Panjab University, Chandigarh, India
| | - Kamalendra Yadav
- National Agri-Food Biotechnology Institute, Sector 81, Mohali, Punjab, India
| | - Aanchal Aggarwal
- National Agri-Food Biotechnology Institute, Sector 81, Mohali, Punjab, India
| | - Nitin Singhal
- National Agri-Food Biotechnology Institute, Sector 81, Mohali, Punjab, India
| | - Rajat Sandhir
- Department of Biochemistry, Basic Medical Science Block II, Panjab University, Chandigarh, India.
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17
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Shi Y, Yuan S, Tang SJ. Morphine and HIV-1 gp120 cooperatively promote pathogenesis in the spinal pain neural circuit. Mol Pain 2020; 15:1744806919868380. [PMID: 31368399 PMCID: PMC6676262 DOI: 10.1177/1744806919868380] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Opioids are common analgesics for pain relief in HIV patients. Ironically, emerging clinical data indicate that repeated use of opioid analgesics in fact leads to a heightened chronic pain state. To understand the underlying pathogenic mechanism, we generated a mouse model to study the interactive effect of morphine and HIV-1 gp120 on pain pathogenesis. We simulated chronic pain in the model by showing that repeated morphine administrations potentiated HIV-1 intrathecal gp120-induced pain. Several spinal cellular and molecular pathologies that are implicated in the development of HIV-associated pain are exacerbated by morphine, including astroglial activation, pro-inflammatory cytokine expression and Wnt5a signaling. We further demonstrated that inhibition of Wnt5a not only reversed the glial activation and cytokine upregulation but also the exacerbation of gp120-induced pain. These studies establish a mouse model for the opioid exacerbation of HIV-associated pain and reveal potential cellular and molecular mechanisms by which morphine enhances the pain.
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Affiliation(s)
- Yuqiang Shi
- 1 Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Subo Yuan
- 1 Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Shao-Jun Tang
- 1 Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX, USA
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18
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Immunomodulatory role of the extracellular matrix protein tenascin-C in neuroinflammation. Biochem Soc Trans 2020; 47:1651-1660. [PMID: 31845742 DOI: 10.1042/bst20190081] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 11/14/2019] [Accepted: 11/25/2019] [Indexed: 02/06/2023]
Abstract
The extracellular matrix (ECM) consists of a dynamic network of various macromolecules that are synthesized and released by surrounding cells into the intercellular space. Glycoproteins, proteoglycans and fibrillar proteins are main components of the ECM. In addition to general functions such as structure and stability, the ECM controls several cellular signaling pathways. In this context, ECM molecules have a profound influence on intracellular signaling as receptor-, adhesion- and adaptor-proteins. Due to its various functions, the ECM is essential in the healthy organism, but also under pathological conditions. ECM constituents are part of the glial scar, which is formed in several neurodegenerative diseases that are accompanied by the activation and infiltration of glia as well as immune cells. Remodeling of the ECM modulates the release of pro- and anti-inflammatory cytokines affecting the fate of immune, glial and neuronal cells. Tenascin-C is an ECM glycoprotein that is expressed during embryonic central nervous system (CNS) development. In adults it is present at lower levels but reappears under pathological conditions such as in brain tumors, following injury and in neurodegenerative disorders and is highly associated with glial reactivity as well as scar formation. As a key modulator of the immune response during neurodegeneration in the CNS, tenascin-C is highlighted in this mini-review.
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Hodges SL, Nolan SO, Tomac LA, Muhammad IDA, Binder MS, Taube JH, Lugo JN. Lipopolysaccharide-induced inflammation leads to acute elevations in pro-inflammatory cytokine expression in a mouse model of Fragile X syndrome. Physiol Behav 2019; 215:112776. [PMID: 31838149 DOI: 10.1016/j.physbeh.2019.112776] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/11/2019] [Accepted: 12/11/2019] [Indexed: 02/07/2023]
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder caused by a single genetic mutation in the Fmr1 gene, serving as the largest genetic cause of intellectual disability. Trinucleotide expansion mutations in Fmr1 result in silencing and hypermethylation of the gene, preventing synthesis of the RNA binding protein Fragile X mental retardation protein which functions as a translational repressor. Abnormal immune responses have been demonstrated to play a role in FXS pathophysiology, however, whether these alterations impact how those with FXS respond to an immune insult behaviorally is not entirely known. In the current study, we examine how Fmr1 knockout (KO) and wild type (WT) mice respond to the innate immune stimulus lipopolysaccharide (LPS), both on a molecular and behavioral level, to determine if Fmr1 mutations impact the normal physiological response to an immune insult. In response to LPS, Fmr1 KO mice had elevated hippocampal IL-1β and IL-6 mRNA levels 4 h post-treatment compared to WT mice, with no differences detected in any cytokines at baseline or between genotypes 24 h post-LPS administration. Fmr1 KO mice also had upregulated hippocampal BDNF gene expression 4 h post-treatment compared to WT mice, which was not dependent on LPS administration. There were no differences in hippocampal protein expression between genotypes in microglia (Iba1) or astrocyte (GFAP) reactivity. Further, both genotypes displayed the typical sickness response following LPS stimulation, demonstrated by a significant reduction in food burrowed by LPS-treated mice in a burrowing task. Additional investigation is critical to determine if the transient increases in cytokine expression could lead to long-term changes in downstream molecular signaling in FXS.
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Affiliation(s)
- Samantha L Hodges
- Institute of Biomedical Studies, Baylor University, Waco, TX 76798, USA
| | - Suzanne O Nolan
- Department of Psychology and Neuroscience, Baylor University, One Bear Place # 97334, Waco, TX 76798, USA
| | - Lindsay A Tomac
- Department of Psychology and Neuroscience, Baylor University, One Bear Place # 97334, Waco, TX 76798, USA
| | - Ilyasah D A Muhammad
- Department of Psychology and Neuroscience, Baylor University, One Bear Place # 97334, Waco, TX 76798, USA
| | - Matthew S Binder
- Department of Psychology and Neuroscience, Baylor University, One Bear Place # 97334, Waco, TX 76798, USA
| | - Joseph H Taube
- Institute of Biomedical Studies, Baylor University, Waco, TX 76798, USA; Department of Biology, Baylor University, Waco, TX 76798, USA
| | - Joaquin N Lugo
- Institute of Biomedical Studies, Baylor University, Waco, TX 76798, USA; Department of Psychology and Neuroscience, Baylor University, One Bear Place # 97334, Waco, TX 76798, USA; Department of Biology, Baylor University, Waco, TX 76798, USA.
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20
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Alvarez-Carbonell D, Ye F, Ramanath N, Garcia-Mesa Y, Knapp PE, Hauser KF, Karn J. Cross-talk between microglia and neurons regulates HIV latency. PLoS Pathog 2019; 15:e1008249. [PMID: 31887215 PMCID: PMC6953890 DOI: 10.1371/journal.ppat.1008249] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 01/10/2020] [Accepted: 12/01/2019] [Indexed: 12/30/2022] Open
Abstract
Despite effective antiretroviral therapy (ART), HIV-associated neurocognitive disorders (HAND) are found in nearly one-third of patients. Using a cellular co-culture system including neurons and human microglia infected with HIV (hμglia/HIV), we investigated the hypothesis that HIV-dependent neurological degeneration results from the periodic emergence of HIV from latency within microglial cells in response to neuronal damage or inflammatory signals. When a clonal hμglia/HIV population (HC69) expressing HIV, or HIV infected human primary and iPSC-derived microglial cells, were cultured for a short-term (24 h) with healthy neurons, HIV was silenced. The neuron-dependent induction of latency in HC69 cells was recapitulated using induced pluripotent stem cell (iPSC)-derived GABAergic cortical (iCort) and dopaminergic (iDopaNer), but not motor (iMotorNer), neurons. By contrast, damaged neurons induce HIV expression in latently infected microglial cells. After 48-72 h co-culture, low levels of HIV expression appear to damage neurons, which further enhances HIV expression. There was a marked reduction in intact dendrites staining for microtubule associated protein 2 (MAP2) in the neurons exposed to HIV-expressing microglial cells, indicating extensive dendritic pruning. To model neurotoxicity induced by methamphetamine (METH), we treated cells with nM levels of METH and suboptimal levels of poly (I:C), a TLR3 agonist that mimics the effects of the circulating bacterial rRNA found in HIV infected patients. This combination of agents potently induced HIV expression, with the METH effect mediated by the σ1 receptor (σ1R). In co-cultures of HC69 cells with iCort neurons, the combination of METH and poly(I:C) induced HIV expression and dendritic damage beyond levels seen using either agent alone, Thus, our results demonstrate that the cross-talk between healthy neurons and microglia modulates HIV expression, while HIV expression impairs this intrinsic molecular mechanism resulting in the excessive and uncontrolled stimulation of microglia-mediated neurotoxicity.
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Affiliation(s)
- David Alvarez-Carbonell
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Fengchun Ye
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Nirmala Ramanath
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Yoelvis Garcia-Mesa
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Pamela E. Knapp
- Departments of Pharmacology and Toxicology and Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
| | - Kurt F. Hauser
- Departments of Pharmacology and Toxicology and Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, United States of America
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Velasco-Estevez M, Rolle SO, Mampay M, Dev KK, Sheridan GK. Piezo1 regulates calcium oscillations and cytokine release from astrocytes. Glia 2019; 68:145-160. [PMID: 31433095 DOI: 10.1002/glia.23709] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 07/16/2019] [Accepted: 08/07/2019] [Indexed: 12/11/2022]
Abstract
Astrocytes are important for information processing in the brain and they achieve this by fine-tuning neuronal communication via continuous uptake and release of biochemical modulators of neurotransmission and synaptic plasticity. Often overlooked are their important functions in mechanosensation. Indeed, astrocytes can detect pathophysiological changes in the mechanical properties of injured, ageing, or degenerating brain tissue. We have recently shown that astrocytes surrounding mechanically-stiff amyloid plaques upregulate the mechanosensitive ion channel, Piezo1. Moreover, ageing transgenic Alzheimer's rats harboring a chronic peripheral bacterial infection displayed enhanced Piezo1 expression in amyloid plaque-reactive astrocytes of the hippocampus and cerebral cortex. Here, we have shown that the bacterial endotoxin, lipopolysaccharide (LPS), also upregulates Piezo1 in primary mouse cortical astrocyte cultures in vitro. Activation of Piezo1, via the small molecule agonist Yoda1, enhanced Ca2+ influx in both control and LPS-stimulated astrocytes. Moreover, Yoda1 augmented intracellular Ca2+ oscillations but decreased subsequent Ca2+ influx in response to adenosine triphosphate (ATP) stimulation. Neither blocking nor activating Piezo1 affected cell viability. However, LPS-stimulated astrocyte cultures exposed to the Piezo1 activator, Yoda1, migrated significantly slower than reactive astrocytes treated with the mechanosensitive channel-blocking peptide, GsMTx4. Furthermore, our data show that activating Piezo1 channels inhibits the release of cytokines and chemokines, such as IL-1β, TNFα, and fractalkine (CX3 CL1), from LPS-stimulated astrocyte cultures. Taken together, our results suggest that astrocytic Piezo1 upregulation may act to dampen neuroinflammation and could be a useful drug target for neuroinflammatory disorders of the brain.
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Affiliation(s)
- María Velasco-Estevez
- Drug Development, Department of Physiology, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Sara O Rolle
- Department of Bioengineering, Imperial College London, London, UK.,Francis Crick Institute, London, UK
| | - Myrthe Mampay
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK
| | - Kumlesh K Dev
- Drug Development, Department of Physiology, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Graham K Sheridan
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK.,School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
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22
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Wenzel TJ, Bajwa E, Klegeris A. Cytochrome c can be released into extracellular space and modulate functions of human astrocytes in a toll-like receptor 4-dependent manner. Biochim Biophys Acta Gen Subj 2019; 1863:129400. [PMID: 31344401 DOI: 10.1016/j.bbagen.2019.07.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 06/23/2019] [Accepted: 07/18/2019] [Indexed: 11/16/2022]
Abstract
BACKGROUND Chronic activation of glial cells contributes to neurodegenerative diseases. Cytochrome c (CytC) is a soluble mitochondrial protein that can act as a damage-associated molecular pattern (DAMP) when released into the extracellular space from damaged cells. CytC causes immune activation of microglia in a toll-like receptor (TLR) 4-dependent manner. The effects of extracellular CytC on astrocytes are unknown. Astrocytes, which are the most abundant glial cell type in the brain, express TLR 4 and secrete inflammatory mediators; therefore, we hypothesized that extracellular CytC can interact with the TLR 4 of astrocytes inducing their release of inflammatory molecules and cytotoxins. METHOD Experiments were conducted using primary human astrocytes, U118 MG human astrocytic cells, BV-2 murine microglia, and SH-SY5Y human neuronal cells. RESULTS Extracellularly applied CytC increased the secretion of interleukin (IL)-1β, granulocyte-macrophage colony stimulating factor (GM-CSF) and IL-12 p70 by cultured primary human astrocytes. Anti-TLR 4 antibodies blocked the CytC-induced secretion of IL-1β and GM-CSF by astrocytes. Supernatants from CytC-activated astrocytes were toxic to human SH-SY5Y neuronal cells. We also demonstrated CytC release from damaged glial cells by measuring CytC in the supernatants of BV-2 microglia after their exposure to cytotoxic concentrations of staurosporine, amyloid-β peptides (Aβ42) and tumor necrosis factor-α. CONCLUSION CytC can be released into the extracellular space from damaged glial cells causing immune activation of astrocytes in a TLR 4-dependent manner. GENERAL SIGNIFICANCE Astrocyte activation by CytC may contribute to neuroinflammation and neuronal death in neurodegenerative diseases. Astrocyte TLR 4 could be a potential therapeutic target in these diseases.
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Affiliation(s)
- Tyler J Wenzel
- Department of Biology, University of British Columbia Okanagan Campus, Kelowna, British Columbia V1V 1V7, Canada
| | - Ekta Bajwa
- Department of Biology, University of British Columbia Okanagan Campus, Kelowna, British Columbia V1V 1V7, Canada
| | - Andis Klegeris
- Department of Biology, University of British Columbia Okanagan Campus, Kelowna, British Columbia V1V 1V7, Canada.
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Camacho-Hernández NP, Lorea-Hernández JJ, Peña-Ortega F. Microglial modulators reduce respiratory rhythm long-term facilitation in vitro. Respir Physiol Neurobiol 2019; 265:9-18. [DOI: 10.1016/j.resp.2018.07.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 06/08/2018] [Accepted: 07/30/2018] [Indexed: 12/28/2022]
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Tremblay ME, Cookson MR, Civiero L. Glial phagocytic clearance in Parkinson's disease. Mol Neurodegener 2019; 14:16. [PMID: 30953527 PMCID: PMC6451240 DOI: 10.1186/s13024-019-0314-8] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 03/15/2019] [Indexed: 12/21/2022] Open
Abstract
An emerging picture suggests that glial cells' loss of beneficial roles or gain of toxic functions can contribute to neurodegenerative conditions. Among glial cells, microglia and astrocytes have been shown to play phagocytic roles by engulfing synapses, apoptotic cells, cell debris, and released toxic proteins. As pathogenic protein accumulation is a key feature in Parkinson's disease (PD), compromised phagocytic clearance might participate in PD pathogenesis. In contrast, enhanced, uncontrolled and potentially toxic glial clearance capacity could contribute to synaptic degeneration. Here, we summarize the current knowledge of the molecular mechanisms underlying microglial and astrocytic phagocytosis, focusing on the possible implication of phagocytic dysfunction in neuronal degeneration. Several endo-lysosomal proteins displaying genetic variants in PD are highly expressed by microglia and astrocytes. We also present the evidence that lysosomal defects can affect phagocytic clearance and discuss the therapeutic relevance of restoring or enhancing lysosomal function in PD.
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Affiliation(s)
- Marie-Eve Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Quebec, QC Canada
- Département de Médecine Moléculaire, Faculté de Médecine, Université Laval, Quebec, QC Canada
| | - Mark R. Cookson
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD USA
| | - Laura Civiero
- Department of Biology, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy
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25
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Kumar V. Toll-like receptors in the pathogenesis of neuroinflammation. J Neuroimmunol 2019; 332:16-30. [PMID: 30928868 DOI: 10.1016/j.jneuroim.2019.03.012] [Citation(s) in RCA: 210] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/19/2019] [Accepted: 03/19/2019] [Indexed: 12/17/2022]
Abstract
Toll-like receptors (TLRs) are discovered as crucial pattern recognition receptors (PRRs) involved in the recognition of pathogen-associated molecular patterns (PAMPs). Later studies showed their involvement in the recognition of various damage/danger-associated molecular patterns (DAMPs) generated by host itself. Thus, TLRs are capable of recognizing wide-array of patterns/molecules derived from pathogens and host as well and initiating a proinflammatory immune response through the activation of NF-κB and other transcription factors causing synthesis of proinflammatory molecules. The process of neuroinflammation is seen under both sterile and infectious inflammatory diseases of the central nervous system (CNS) and may lead to the development of neurodegeneration. The present article is designed to highlight the importance of TLRs in the pathogenesis of neuroinflammation under diverse conditions. TLRs are expressed by various immune cells present in CNS along with neurons. However out of thirteen TLRs described in mammals, some are present and active in these cells, while some are absent and are described in detail in main text. The role of various immune cells present in the brain and their role in the pathogenesis of neuroinflammation depending on the type of TLR expressed is described. Thereafter the role of TLRs in bacterial meningitis, viral encephalitis, stroke, Alzheimer's disease (AD), Parkinson's disease (PD), and autoimmune disease including multiple sclerosis (MS) is described. The article is designed for both neuroscientists needing information regarding TLRs in neuroinflammation and TLR biologists or immunologists interested in neuroinflammation.
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Affiliation(s)
- V Kumar
- Children Health Clinical Unit, School of Clinical Medicine, Faculty of Medicine, Mater Research, University of Queensland, ST Lucia, Brisbane, Queensland 4078, Australia; School of Biomedical Sciences, Faculty of Medicine, University of Queensland, ST Lucia, Brisbane, Queensland 4078, Australia.
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26
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Astroglia in Sepsis Associated Encephalopathy. Neurochem Res 2019; 45:83-99. [PMID: 30778837 PMCID: PMC7089215 DOI: 10.1007/s11064-019-02743-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 01/25/2019] [Accepted: 01/28/2019] [Indexed: 01/07/2023]
Abstract
Cellular pathophysiology of sepsis associated encephalopathy (SAE) remains poorly characterised. Brain pathology in SAE, which is manifested by impaired perception, consciousness and cognition, results from multifactorial events, including high levels of systemic cytokines, microbial components and endotoxins, which all damage the brain barriers, instigate neuroinflammation and cause homeostatic failure. Astrocytes, being the principal homeostatic cells of the central nervous system contribute to the brain defence against infection. Forming multifunctional anatomical barriers, astroglial cells maintain brain-systemic interfaces and restrict the damage to the nervous tissue. Astrocytes detect, produce and integrate inflammatory signals between immune cells and cells of brain parenchyma, thus regulating brain immune response. In SAE astrocytes are present in both reactive and astrogliopathic states; balance between these states define evolution of pathology and neurological outcomes. In humans pathophysiology of SAE is complicated by frequent presence of comorbidities, as well as age-related remodelling of the brain tissue with senescence of astroglia; these confounding factors further impact upon SAE progression and neurological deficits.
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Verkhratsky A, Ho MS, Vardjan N, Zorec R, Parpura V. General Pathophysiology of Astroglia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1175:149-179. [PMID: 31583588 PMCID: PMC7188602 DOI: 10.1007/978-981-13-9913-8_7] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Astroglial cells are involved in most if not in all pathologies of the brain. These cells can change the morpho-functional properties in response to pathology or innate changes of these cells can lead to pathologies. Overall pathological changes in astroglia are complex and diverse and often vary with different disease stages. We classify astrogliopathologies into reactive astrogliosis, astrodegeneration with astroglial atrophy and loss of function, and pathological remodelling of astrocytes. Such changes can occur in neurological, neurodevelopmental, metabolic and psychiatric disorders as well as in infection and toxic insults. Mutation in astrocyte-specific genes leads to specific pathologies, such as Alexander disease, which is a leukodystrophy. We discuss changes in astroglia in the pathological context and identify some molecular entities underlying pathology. These entities within astroglia may repent targets for novel therapeutic intervention in the management of brain pathologies.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
- Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Margaret S Ho
- School of Life Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Nina Vardjan
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
- Celica BIOMEDICAL, Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
- Celica BIOMEDICAL, Ljubljana, Slovenia
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
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Abstract
Viral infection in the brain can be acute or chronic, with the responses often producing foci of increasingly cytotoxic inflammation. This can lead to effects beyond the central nervous system (CNS). To stimulate discussion, this commentary addresses four questions: What drives the development of human immunodeficiency virus (HIV)-associated neurocognitive disorders, does the phenotype of macrophages in the CNS spur development of HIV encephalitis (HIVE), does continual activation of astrocytes drive the development of HIV-associated neurocognitive disorders/subclinical disease, and neuroinflammation: friend or foe? A unifying theory that connects each question is the issue of continued activation of glial cells, even in the apparent absence of simian immunodeficiency virus/HIV in the CNS. As the CNS innate immune system is distinct from the rest of the body, it is likely there could be a number of activation profiles not observed elsewhere.
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Affiliation(s)
- Elizabeth C. Delery
- Tulane National Primate Research Center, Covington, Louisiana
- Tulane Program in Biomedical Sciences, Tulane Medical School, New Orleans, Louisiana
- Department of Microbiology and Immunology, Tulane Medical School, New Orleans, Louisiana
| | - Andrew G. MacLean
- Tulane National Primate Research Center, Covington, Louisiana
- Tulane Program in Biomedical Sciences, Tulane Medical School, New Orleans, Louisiana
- Department of Microbiology and Immunology, Tulane Medical School, New Orleans, Louisiana
- Tulane Brain Institute, Tulane University, New Orleans, Louisiana
- Center for Aging, School of Medicine, Tulane University, New Orleans, Louisiana
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29
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Krasovska V, Doering LC. Regulation of IL-6 Secretion by Astrocytes via TLR4 in the Fragile X Mouse Model. Front Mol Neurosci 2018; 11:272. [PMID: 30123107 PMCID: PMC6085486 DOI: 10.3389/fnmol.2018.00272] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 07/17/2018] [Indexed: 01/15/2023] Open
Abstract
Fragile X syndrome (FXS) is identified by abnormal dendrite morphology and altered synaptic protein expression. Astrocyte secreted factors such as Tenascin C (TNC), may contribute to the synaptic changes, including maturation of the synapse. TNC is a known endogenous ligand of toll-like receptor 4 (TLR4) that has been shown to induce the expression of pro-inflammatory cytokines such as interleukin-6 (IL-6). At the molecular level, elevated IL-6 promotes excitatory synapse formation and increases dendrite spine length. With these molecular changes linked to the phenotype of FXS, we examined the expression and the mechanism of the endogenous TLR4 activator TNC, and its downstream target IL-6 in astrocytes from the Fragile X Mental Retardation 1 (FMR1) knockout (KO) mouse model. Secreted TNC and IL-6 were significantly increased in FMR1 KO astrocytes. Addition of TNC and lipopolysaccharide (LPS) induced IL-6 secretion, whereas the antagonist of TLR4 (LPS-RS) had an opposing effect. Cortical protein expression of TNC and IL-6 were also significantly elevated in the postnatal FMR1 KO mouse. In addition, there was an increase in the number of vesicular glutamate transporter 1 (VGLUT1)/post synaptic density protein 95 (PSD95) positive synaptic puncta of both wild-type (WT) and FMR1 KO neurons when plated with astrocyte conditioned media (ACM) from FMR1 KO astrocytes, compared to those plated with media from wild type astrocytes. By assessing the cellular mechanisms involved, a novel therapeutic option could be made available to target abnormalities of synaptic function seen in FXS.
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Affiliation(s)
| | - Laurie C. Doering
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
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30
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Yang L, Niu F, Yao H, Liao K, Chen X, Kook Y, Ma R, Hu G, Buch S. Exosomal miR-9 Released from HIV Tat Stimulated Astrocytes Mediates Microglial Migration. J Neuroimmune Pharmacol 2018; 13:330-344. [PMID: 29497921 DOI: 10.1007/s11481-018-9779-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 02/19/2018] [Indexed: 12/22/2022]
Abstract
Chronic neuroinflammation still remains a common underlying feature of HIV-infected patients on combined anti-retroviral therapy (cART). Previous studies have reported that despite near complete suppression of virus replication by cART, cytotoxic viral proteins such as HIV trans-activating regulatory protein (Tat) continue to persist in tissues such as the brain and the lymph nodes, thereby contributing, in part, to chronic glial activation observed in HIV-associated neurological disorders (HAND). Understanding how the glial cells cross talk to mediate neuropathology is thus of paramount importance. MicroRNAs (miR) also known as regulators of gene expression, have emerged as key paracrine signaling mediators that regulate disease pathogenesis and cellular crosstalk, through their transfer via the extracellular vesicles (EV). In the current study we have identified a novel function of miR-9, that of mediating microglial migration. We demonstrate that miR-9 released from Tat-stimulated astrocytes can be taken up by microglia resulting in their migratory phenotype. Exposure of human astrocytoma (A172) cells to HIV Tat resulted in induction and release of miR-9 in the EVs, which, was taken up by microglia, leading in turn, increased migration of the latter cells, a process that could be blocked by both an exosome inhibitor GW4869 or a specific target protector of miR-9. Furthermore, it was also demonstrated that EV miR-9 mediated inhibition of the expression of target PTEN, via its binding to the 3'UTR seed sequence of the PTEN mRNA, was critical for microglial migration. To validate the role of miR-9 in this process, microglial cells were treated with EVs loaded with miR-9, which resulted in significant downregulation of PTEN expression with a concomitant increase in microglial migration. These findings were corroborated by transfecting microglia with a specific target protector of PTEN, that blocked miR-9-mediated downregulation of PTEN as well as microglial migration. In vivo studies wherein the miR-9 precursor-transduced microglia were transplanted into the striatum of mice, followed by assessing their migration in response to a stimulus administered distally, further validated the role of miR-9 in mediating microglial migration. Collectively, our findings provide evidence that glial crosstalk via miRs released from EVs play a vital role in mediating disease pathogenesis and could provide new avenues for development of novel therapeutic strategies aimed at dampening neuropathogenesis.
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Affiliation(s)
- Lu Yang
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Fang Niu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Honghong Yao
- Department of Pharmacology, Medical School of Southeast University, Southeast University, Nanjing, China.,Key Laboratory of Developmental Genes and Human Disease, Southeast University, Institute of Life Sciences, Nanjing, China
| | - Ke Liao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Xufeng Chen
- The first Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Yeonhee Kook
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Rong Ma
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Guoku Hu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA.
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Llewellyn GN, Alvarez-Carbonell D, Chateau M, Karn J, Cannon PM. HIV-1 infection of microglial cells in a reconstituted humanized mouse model and identification of compounds that selectively reverse HIV latency. J Neurovirol 2017; 24:192-203. [PMID: 29256041 PMCID: PMC5910454 DOI: 10.1007/s13365-017-0604-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 11/03/2017] [Accepted: 11/09/2017] [Indexed: 11/24/2022]
Abstract
Most studies of HIV latency focus on the peripheral population of resting memory T cells, but the brain also contains a distinct reservoir of HIV-infected cells in microglia, perivascular macrophages, and astrocytes. Studying HIV in the brain has been challenging, since live cells are difficult to recover from autopsy samples and primate models of SIV infection utilize viruses that are more myeloid-tropic than HIV due to the expression of Vpx. Development of a realistic small animal model would greatly advance studies of this important reservoir and permit definitive studies of HIV latency. When radiation or busulfan-conditioned, immune-deficient NSG mice are transplanted with human hematopoietic stem cells, human cells from the bone marrow enter the brain and differentiate to express microglia-specific markers. After infection with replication competent HIV, virus was detected in these bone marrow-derived human microglia. Studies of HIV latency in this model would be greatly enhanced by the development of compounds that can selectively reverse HIV latency in microglial cells. Our studies have identified members of the CoREST repression complex as key regulators of HIV latency in microglia in both rat and human microglial cell lines. The monoamine oxidase (MAO) and potential CoREST inhibitor, phenelzine, which is brain penetrant, was able to stimulate HIV production in human microglial cell lines and human glial cells recovered from the brains of HIV-infected humanized mice. The humanized mice we have developed therefore show great promise as a model system for the development of strategies aimed at defining and reducing the CNS reservoir.
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Affiliation(s)
- George N Llewellyn
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - David Alvarez-Carbonell
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Morgan Chateau
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
| | - Paula M Cannon
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
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Rocha Sobrinho HMD, Silva DJD, Gomides LF, Dorta ML, Oliveira MAPD, Ribeiro-Dias F. TLR4 and TLR2 activation is differentially associated with age during Parkinson’s disease. Immunol Invest 2017; 47:71-88. [DOI: 10.1080/08820139.2017.1379024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
| | - Delson José da Silva
- Hospital das Clínicas, Universidade Federal de Goiás and Instituto Integrado de Neurociências, Goiânia, Goiás, Brazil
| | - Larissa Fonseca Gomides
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Miriam Leandro Dorta
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | | | - Fátima Ribeiro-Dias
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
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Liao Y, Jiang J, Liang B, Wei F, Huang J, Pan P, Su J, Zhou B, Zang N, Ye L, Liang H. Opiate use inhibits TLR9 signaling pathway in vivo: possible role in pathogenesis of HIV-1 infection. Sci Rep 2017; 7:13071. [PMID: 29026137 PMCID: PMC5638828 DOI: 10.1038/s41598-017-12066-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 07/28/2017] [Indexed: 01/06/2023] Open
Abstract
The molecular mechanism of opiate use promoting HIV-1 infection is not fully understood. TLR9 is expressed in many immune cells, including monocytes, macrophages, which can recognize viruses and viral products and consequently induce the production of antiviral factors and initiate immune responses. Previous studies have shown that chronic viral infections can overcome and impair TLR9 pathway. We aimed to explore whether opiate use enhances HIV infection through inhibition of TLR9 pathway via a population-based study. A total of 200 subjects were enrolled and divided into four groups as follows: Opiate+ HIV+ (50), Opiate- HIV+ (50), Opiate+ HIV- (50), and healthy control (Opiate- HIV-, 50). All HIV-infected subjects did not receive antiretroviral therapy while they were enrolled in the study. The results showed that opiate use was associated with higher viral load and lower CD4+ T cell count. Opiate use alone led to lower expression of TLR9, IRF7, and IFN-α at the protein level in PBMCs. Combined with HIV-1 infection, opiate use resulted in lower expression of MyD88, ISG56, and MxA. In addition, morphine treatment promoted HIV-1 replication in macrophages via inhibition of TLR9 pathway. Our data reveal that opiate use plays a cofactor role in pathogenesis of HIV-1 infection through inhibition of TLR9 pathway.
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Affiliation(s)
- Yanyan Liao
- Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Universities Key Laboratory of Prevention and Control of Highly Prevalent Disease, School of Public Health, Guangxi Medical University, Nanning, China
- Guangxi Collaborative Innovation Center for Biomedicine, Life Science Institute, Guangxi Medical University, Nanning, China
| | - Junjun Jiang
- Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Universities Key Laboratory of Prevention and Control of Highly Prevalent Disease, School of Public Health, Guangxi Medical University, Nanning, China
- Guangxi Collaborative Innovation Center for Biomedicine, Life Science Institute, Guangxi Medical University, Nanning, China
| | - Bingyu Liang
- Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Universities Key Laboratory of Prevention and Control of Highly Prevalent Disease, School of Public Health, Guangxi Medical University, Nanning, China
| | - Fumei Wei
- Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Universities Key Laboratory of Prevention and Control of Highly Prevalent Disease, School of Public Health, Guangxi Medical University, Nanning, China
| | - Jiegang Huang
- Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Universities Key Laboratory of Prevention and Control of Highly Prevalent Disease, School of Public Health, Guangxi Medical University, Nanning, China
| | - Peijiang Pan
- Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Universities Key Laboratory of Prevention and Control of Highly Prevalent Disease, School of Public Health, Guangxi Medical University, Nanning, China
| | - Jinming Su
- Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Universities Key Laboratory of Prevention and Control of Highly Prevalent Disease, School of Public Health, Guangxi Medical University, Nanning, China
| | - Bo Zhou
- Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Universities Key Laboratory of Prevention and Control of Highly Prevalent Disease, School of Public Health, Guangxi Medical University, Nanning, China
- Guangxi Collaborative Innovation Center for Biomedicine, Life Science Institute, Guangxi Medical University, Nanning, China
| | - Ning Zang
- Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Universities Key Laboratory of Prevention and Control of Highly Prevalent Disease, School of Public Health, Guangxi Medical University, Nanning, China
- Guangxi Collaborative Innovation Center for Biomedicine, Life Science Institute, Guangxi Medical University, Nanning, China
| | - Li Ye
- Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Universities Key Laboratory of Prevention and Control of Highly Prevalent Disease, School of Public Health, Guangxi Medical University, Nanning, China.
- Guangxi Collaborative Innovation Center for Biomedicine, Life Science Institute, Guangxi Medical University, Nanning, China.
| | - Hao Liang
- Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Universities Key Laboratory of Prevention and Control of Highly Prevalent Disease, School of Public Health, Guangxi Medical University, Nanning, China.
- Guangxi Collaborative Innovation Center for Biomedicine, Life Science Institute, Guangxi Medical University, Nanning, China.
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Scutari R, Alteri C, Perno CF, Svicher V, Aquaro S. The Role of HIV Infection in Neurologic Injury. Brain Sci 2017; 7:E38. [PMID: 28383502 PMCID: PMC5406695 DOI: 10.3390/brainsci7040038] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/27/2017] [Accepted: 03/30/2017] [Indexed: 12/20/2022] Open
Abstract
The central nervous system (CNS) is a very challenging HIV-1 sanctuary, in which HIV-1 replication is established early on during acute infection and can persist despite potent antiretroviral treatments. HIV-1 infected macrophages play a pivotal role acting as vehicles for HIV-1 to spread into the brain, and can be the major contributor of an early compartmentalization. HIV-1 infection in CNS may lead to a broad spectrum of neurological syndromes, such as dementia, mild neurocognitive disorders, and asymptomatic impairment. These clinical manifestations are caused by the release of neurotoxins from infected cells (mainly macrophages), and also by several HIV-1 proteins, able to activate cell-signaling involved in the control of cellular survival and apoptosis. This review is aimed at highlighting the virological aspects associated with the onset of neurocognitive disorders and at addressing the novel therapeutic approaches to stop HIV-1 replication in this critical sanctuary.
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Affiliation(s)
- Rossana Scutari
- Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Rome 00133, Italy.
| | - Claudia Alteri
- Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Rome 00133, Italy.
| | - Carlo Federico Perno
- Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Rome 00133, Italy.
| | - Valentina Svicher
- Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Rome 00133, Italy.
| | - Stefano Aquaro
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Arcavacata di Rende (CS) 87036, Italy.
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Alvarez-Carbonell D, Garcia-Mesa Y, Milne S, Das B, Dobrowolski C, Rojas R, Karn J. Toll-like receptor 3 activation selectively reverses HIV latency in microglial cells. Retrovirology 2017; 14:9. [PMID: 28166799 PMCID: PMC5294768 DOI: 10.1186/s12977-017-0335-8] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 01/19/2017] [Indexed: 01/27/2023] Open
Abstract
Background Multiple toll-like receptors (TLRs) are expressed in cells of the monocytic lineage, including microglia, which constitute the major reservoir for human immunodeficiency virus (HIV) infection in the brain. We hypothesized that TLR receptor mediated responses to inflammatory conditions by microglial cells in the central nervous system (CNS) are able to induce latent HIV proviruses, and contribute to the etiology of HIV-associated neurocognitive disorders. Results Newly developed human microglial cell lines (hµglia), obtained by immortalizing human primary microglia with simian virus-40 (SV40) large T antigen and the human telomerase reverse transcriptase, were used to generate latently infected cells using a single-round HIV virus carrying a green fluorescence protein reporter (hµglia/HIV, clones HC01 and HC69). Treatment of these cells with a panel of TLR ligands showed surprisingly that two potent TLR3 agonists, poly (I:C) and bacterial ribosomal RNA potently reactivated HIV in hμglia/HIV cells. LPS (TLR4 agonist), flagellin (TLR5 agonist), and FSL-1 (TLR6 agonist) reactivated HIV to a lesser extent, while Pam3CSK4 (TLR2/1 agonist) and HKLM (TLR2 agonist) only weakly reversed HIV latency in these cells. While agonists for TLR2/1, 4, 5 and 6 reactivated HIV through transient NF-κB induction, poly (I:C), the TLR3 agonist, did not activate NF-κB, and instead induced the virus by a previously unreported mechanism mediated by IRF3. The selective induction of IRF3 by poly (I:C) was confirmed by chromatin immunoprecipitation (ChIP) analysis. In comparison, in latently infected rat-derived microglial cells (hT-CHME-5/HIV, clone HC14), poly (I:C), LPS and flagellin were only partially active. The TLR response profile in human microglial cells is also distinct from that shown by latently infected monocyte cell lines (THP-1/HIV, clone HA3, U937/HIV, clone HUC5, and SC/HIV, clone HSCC4), where TLR2/1, 4, 5, 6 or 8, but not for TLR3, 7 or 9, reactivated HIV. Conclusions TLR signaling, in particular TLR3 activation, can efficiently reactivate HIV transcription in infected microglia, but not in monocytes or T cells. The unique response profile of microglial cells to TLR3 is fundamental to understanding how the virus responds to continuous microbial exposure, especially during inflammatory episodes, that characterizes HIV infection in the CNS. Electronic supplementary material The online version of this article (doi:10.1186/s12977-017-0335-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- David Alvarez-Carbonell
- Department of Molecular Biology and Microbiology, Case Western Reserve University, 10900 Euclid Ave., SOM WRT 200, Cleveland, OH, 44106, USA
| | - Yoelvis Garcia-Mesa
- Department of Molecular Biology and Microbiology, Case Western Reserve University, 10900 Euclid Ave., SOM WRT 200, Cleveland, OH, 44106, USA
| | - Stephanie Milne
- Department of Molecular Biology and Microbiology, Case Western Reserve University, 10900 Euclid Ave., SOM WRT 200, Cleveland, OH, 44106, USA
| | - Biswajit Das
- Department of Molecular Biology and Microbiology, Case Western Reserve University, 10900 Euclid Ave., SOM WRT 200, Cleveland, OH, 44106, USA
| | - Curtis Dobrowolski
- Department of Molecular Biology and Microbiology, Case Western Reserve University, 10900 Euclid Ave., SOM WRT 200, Cleveland, OH, 44106, USA
| | - Roxana Rojas
- Department of Molecular Biology and Microbiology, Case Western Reserve University, 10900 Euclid Ave., SOM WRT 200, Cleveland, OH, 44106, USA
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, Case Western Reserve University, 10900 Euclid Ave., SOM WRT 200, Cleveland, OH, 44106, USA.
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Peña-Ortega F. Pharmacological Tools to Activate Microglia and their Possible use to Study Neural Network Patho-physiology. Curr Neuropharmacol 2017; 15:595-619. [PMID: 27697040 PMCID: PMC5543677 DOI: 10.2174/1570159x14666160928151546] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/05/2016] [Accepted: 09/26/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Microglia are the resident immunocompetent cells of the CNS and also constitute a unique cell type that contributes to neural network homeostasis and function. Understanding microglia cell-signaling not only will reveal their diverse functions but also will help to identify pharmacological and non-pharmacological tools to modulate the activity of these cells. METHODS We undertook a search of bibliographic databases for peer-reviewed research literature to identify microglial activators and their cell-specificity. We also looked for their effects on neural network function and dysfunction. RESULTS We identified several pharmacological targets to modulate microglial function, which are more or less specific (with the proper control experiments). We also identified pharmacological targets that would require the development of new potent and specific modulators. We identified a wealth of evidence about the participation of microglia in neural network function and their alterations in pathological conditions. CONCLUSION The identification of specific microglia-activating signals provides experimental tools to modulate the activity of this heterogeneous cell type in order to evaluate its impact on other components of the nervous system, and it also helps to identify therapeutic approaches to ease some pathological conditions related to microglial dysfunction.
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Affiliation(s)
- Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
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Thakur KK, Saini J, Mahajan K, Singh D, Jayswal DP, Mishra S, Bishayee A, Sethi G, Kunnumakkara AB. Therapeutic implications of toll-like receptors in peripheral neuropathic pain. Pharmacol Res 2017; 115:224-232. [DOI: 10.1016/j.phrs.2016.11.019] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 10/28/2016] [Accepted: 11/20/2016] [Indexed: 12/13/2022]
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Fatima M, Prajapati B, Saleem K, Kumari R, Mohindar Singh Singal C, Seth P. Novel insights into role of miR-320a-VDAC1 axis in astrocyte-mediated neuronal damage in neuroAIDS. Glia 2016; 65:250-263. [PMID: 27761954 DOI: 10.1002/glia.23089] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 09/10/2016] [Accepted: 09/30/2016] [Indexed: 12/31/2022]
Abstract
Astroglia are indispensable component of the tripartite synapse ensheathing innumerous soma and synapses. Its proximity to neurons aids the regulation of neuronal functions, health and survival through dynamic neuroglia crosstalk. Susceptibility of astrocyte to HIV-1 infection and subsequent latency culminates in compromised neuronal health. The viral protein HIV-1 transactivator of transcription (Tat) is neurotoxic. HIV-1 Tat is detected in brain of AIDS patients even in cases where viral load is non-detectable due to successful HAART therapy. Recently, we demonstrated that HIV-1 Tat triggers excess ATP release from astrocytes that causes neuronal death by activating purinergic receptor system. Using well-characterized model system of human primary astrocytes and neurons, we probed into the molecular mechanism for enhanced ATP release in HIV-1 Tat affected astrocytes. HIV-1 Tat modulated the miRNA machinery in astrocytes and perturbed the levels of voltage dependent anion channel 1 (VDAC1), a channel present in the outer mitochondrial membrane and plasma membrane that regulates extracellular ATP release. Our studies with autopsy tissue sections also showed concordantly dysregulated VDAC1 and miR-320a levels in HIV-1 patients suffering from mild cognitive impairment (MCI). We report a novel molecular cascade of miRNA-mediated ATP release through regulation of VDAC1. Downregulation of VDAC1 either with miR-320a mimic or VDAC1 siRNA in HIV-1 Tat-affected astroglia could rescue the neurons from glia-mediated indirect death. Our findings reveal a novel upstream therapeutic target that could be employed to thwart the astroglia-mediated neurotoxicity in HIV-1 neuropathogenesis. GLIA 2017;65:250-263.
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Affiliation(s)
- Mahar Fatima
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Gurgaon, Haryana, India
| | - Bharat Prajapati
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Gurgaon, Haryana, India
| | - Kanza Saleem
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Gurgaon, Haryana, India
| | - Rina Kumari
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Gurgaon, Haryana, India
| | - Chitra Mohindar Singh Singal
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Gurgaon, Haryana, India
| | - Pankaj Seth
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Gurgaon, Haryana, India
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Aalinkeel R, Mahajan SD. Neuroprotective role of galectin-1 in central nervous system pathophysiology. Neural Regen Res 2016; 11:896-7. [PMID: 27482206 PMCID: PMC4962575 DOI: 10.4103/1673-5374.184455] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
- Ravikumar Aalinkeel
- Department of Medicine, Division of Allergy, Immunology, and Rheumatology, State University of New York at Buffalo, Clinical Translational Research Center, Buffalo, NY, USA
| | - Supriya D Mahajan
- Department of Medicine, Division of Allergy, Immunology, and Rheumatology, State University of New York at Buffalo, Clinical Translational Research Center, Buffalo, NY, USA
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Kato J, Agalave NM, Svensson CI. Pattern recognition receptors in chronic pain: Mechanisms and therapeutic implications. Eur J Pharmacol 2016; 788:261-273. [PMID: 27343378 DOI: 10.1016/j.ejphar.2016.06.039] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 06/22/2016] [Accepted: 06/22/2016] [Indexed: 12/13/2022]
Abstract
For the individual, it is vital to promptly detect and recognize a danger that threatens the integrity of the body. Pattern recognition receptors (PRRs) are several classes of protein families originally classified as receptors detecting exogenous pathogens. PRRs are also capable of recognizing molecules released from damaged tissues (damage-associated molecular pattern molecules; DAMPs) and thereby contribute to danger recognition. Importantly, it is now evident that PRRs, such as toll-like receptors (TLRs) and receptors for advanced glycation end products (RAGE), are not only expressed in peripheral immune cells but also present in neurons and glial cells in the nervous system. These PRR-expressing cells work in concert, enabling highly sensitive danger recognition. However, this sensitiveness can act as a double-edged sword. Accumulated evidence has led to the hypothesis that aberrant activation of PRRs may play a crucial role in the pathogenesis of pathological pain. Indeed, numerous studies employing gene deletion or pharmacological inhibition of PRRs successfully reversed or prevented pathological pain in experimental animal models. Furthermore, a number of preclinical studies have shown the therapeutic potential of targeting PRRs for chronic pain. Here, we review the current knowledge regarding the role of PRRs in chronic pain and discuss the promise and challenges of targeting PRRs as a novel therapeutic approach for chronic pain.
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Affiliation(s)
- Jungo Kato
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
| | - Nilesh M Agalave
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Camilla I Svensson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Shahin RMH, El Khateeb E, Khalifa RH, El Refai RM. Contribution of Toll-Like Receptor 9 Gene Single-Nucleotide Polymorphism to Systemic Lupus Erythematosus in Egyptian Patients. Immunol Invest 2016; 45:235-42. [DOI: 10.3109/08820139.2015.1137934] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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42
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Reid WC, Ibrahim WG, Kim SJ, Denaro F, Casas R, Lee DE, Maric D, Hammoud DA. Characterization of neuropathology in the HIV-1 transgenic rat at different ages. J Neuroimmunol 2016; 292:116-25. [PMID: 26943969 DOI: 10.1016/j.jneuroim.2016.01.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/27/2016] [Accepted: 01/31/2016] [Indexed: 02/08/2023]
Abstract
The transgenic HIV-1 rat (Tg) is a commonly used neuroHIV model with documented neurologic/behavioral deficits. Using immunofluorescent staining of the Tg brain, we found astrocytic dysfunction/damage, as well as dopaminergic neuronal loss/dysfunction, both of which worsening significantly in the striatum with age. We saw mild microglial activation in young Tg brains, but this decreased with age. There were no differences in neurogenesis potential suggesting a neurodegenerative rather than a neurodevelopmental process. Gp120 CSF levels exceeded serum gp120 levels in some animals, suggesting local viral protein production in the brain. Further probing of the pathophysiology underlying astrocytic injury in this model is warranted.
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Affiliation(s)
- William C Reid
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Wael G Ibrahim
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Saejeong J Kim
- Frank Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Frank Denaro
- Department of Biology, Morgan State University, Baltimore, MD, USA
| | - Rafael Casas
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Dianne E Lee
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Dragan Maric
- Division of Intermural Research (DIR), National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, MD, USA
| | - Dima A Hammoud
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA.
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Reiss CS. Innate Immunity in Viral Encephalitis. NEUROTROPIC VIRAL INFECTIONS 2016. [PMCID: PMC7153449 DOI: 10.1007/978-3-319-33189-8_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Carol Shoshkes Reiss
- Departments of Biology and Neural Science, New York University, New York, New York USA
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Marinelli C, Di Liddo R, Facci L, Bertalot T, Conconi MT, Zusso M, Skaper SD, Giusti P. Ligand engagement of Toll-like receptors regulates their expression in cortical microglia and astrocytes. J Neuroinflammation 2015; 12:244. [PMID: 26714634 PMCID: PMC4696218 DOI: 10.1186/s12974-015-0458-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 12/15/2015] [Indexed: 12/13/2022] Open
Abstract
Background Toll-like receptor (TLR) activation on microglia and astrocytes are key elements in neuroinflammation which accompanies a number of neurological disorders. While TLR activation on glia is well-established to up-regulate pro-inflammatory mediator expression, much less is known about how ligand engagement of one TLR may affect expression of other TLRs on microglia and astrocytes. Methods In the present study, we evaluated the effects of agonists for TLR2 (zymosan), TLR3 (polyinosinic-polycytidylic acid (poly(I:C)), a synthetic analogue of double-stranded RNA) and TLR4 (lipopolysaccaride (LPS)) in influencing expression of their cognate receptor as well as that of the other TLRs in cultures of rat cortical purified microglia (>99.5 %) and nominally microglia-free astrocytes. Elimination of residual microglia (a common contaminant of astrocyte cultures) was achieved by incubation with the lysosomotropic agent l-leucyl-l-leucine methyl ester (L-LME). Results Flow cytometric analysis confirmed the purity (essentially 100 %) of the obtained microglia, and up to 5 % microglia contamination of astrocytes. L-LME treatment effectively removed microglia from the latter (real-time polymerase chain reaction). The three TLR ligands robustly up-regulated gene expression for pro-inflammatory markers (interleukin-1 and interleukin-6, tumor necrosis factor) in microglia and enriched, but not purified, astrocytes, confirming cellular functionality. LPS, zymosan and poly(I:C) all down-regulated TLR4 messenger RNA (mRNA) and up-regulated TLR2 mRNA at 6 and 24 h. In spite of their inability to elaborate pro-inflammatory mediator output, the nominally microglia-free astrocytes (>99 % purity) also showed similar behaviours to those of microglia, as well as changes in TLR3 gene expression. LPS interaction with TLR4 activates downstream mitogen-activated protein kinase and nuclear factor-κB signalling pathways and subsequently causes inflammatory mediator production. The effects of LPS on TLR2 mRNA in both cell populations were antagonized by a nuclear factor-κB inhibitor. Conclusions TLR2 and TLR4 activation in particular, in concert with microglia and astrocytes, comprise key elements in the initiation and maintenance of neuropathic pain. The finding that both homologous (zymosan) and heterologous (LPS, poly(I:C)) TLR ligands are capable of regulating TLR2 gene expression, in particular, may have important implications in understanding the relative contributions of different TLRs in neurological disorders associated with neuroinflammation. Electronic supplementary material The online version of this article (doi:10.1186/s12974-015-0458-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Carla Marinelli
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo "E. Meneghetti" 2, 35131, Padua, Italy.
| | - Rosa Di Liddo
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo "E. Meneghetti" 2, 35131, Padua, Italy.
| | - Laura Facci
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo "E. Meneghetti" 2, 35131, Padua, Italy.
| | - Thomas Bertalot
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo "E. Meneghetti" 2, 35131, Padua, Italy.
| | - Maria Teresa Conconi
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo "E. Meneghetti" 2, 35131, Padua, Italy.
| | - Morena Zusso
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo "E. Meneghetti" 2, 35131, Padua, Italy.
| | - Stephen D Skaper
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo "E. Meneghetti" 2, 35131, Padua, Italy.
| | - Pietro Giusti
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo "E. Meneghetti" 2, 35131, Padua, Italy.
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Lorea-Hernández JJ, Morales T, Rivera-Angulo AJ, Alcantara-Gonzalez D, Peña-Ortega F. Microglia modulate respiratory rhythm generation and autoresuscitation. Glia 2015; 64:603-19. [DOI: 10.1002/glia.22951] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Revised: 11/18/2015] [Accepted: 11/18/2015] [Indexed: 12/21/2022]
Affiliation(s)
- Jonathan-Julio Lorea-Hernández
- Departamento de Neurobiología del Desarrollo y Neurofisiología; Instituto De Neurobiología, UNAM Campus Juriquilla; Querétaro México
| | - Teresa Morales
- Departamento de Neurobiología del Desarrollo y Neurofisiología; Instituto De Neurobiología, UNAM Campus Juriquilla; Querétaro México
| | - Ana-Julia Rivera-Angulo
- Departamento de Neurobiología del Desarrollo y Neurofisiología; Instituto De Neurobiología, UNAM Campus Juriquilla; Querétaro México
| | - David Alcantara-Gonzalez
- Departamento de Neurobiología del Desarrollo y Neurofisiología; Instituto De Neurobiología, UNAM Campus Juriquilla; Querétaro México
| | - Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología; Instituto De Neurobiología, UNAM Campus Juriquilla; Querétaro México
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Borgmann K, Ghorpade A. HIV-1, methamphetamine and astrocytes at neuroinflammatory Crossroads. Front Microbiol 2015; 6:1143. [PMID: 26579077 PMCID: PMC4621459 DOI: 10.3389/fmicb.2015.01143] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 10/05/2015] [Indexed: 12/30/2022] Open
Abstract
As a popular psychostimulant, methamphetamine (METH) use leads to long-lasting, strong euphoric effects. While METH abuse is common in the general population, between 10 and 15% of human immunodeficiency virus-1 (HIV-1) patients report having abused METH. METH exacerbates the severity and onset of HIV-1-associated neurocognitive disorders (HAND) through direct and indirect mechanisms. Repetitive METH use impedes adherence to antiretroviral drug regimens, increasing the likelihood of HIV-1 disease progression toward AIDS. METH exposure also directly affects both innate and adaptive immunity, altering lymphocyte numbers and activity, cytokine signaling, phagocytic function and infiltration through the blood brain barrier. Further, METH triggers the dopamine reward pathway and leads to impaired neuronal activity and direct toxicity. Concurrently, METH and HIV-1 alter the neuroimmune balance and induce neuroinflammation, which modulates a wide range of brain functions including neuronal signaling and activity, glial activation, viral infection, oxidative stress, and excitotoxicity. Pathologically, reactive gliosis is a hallmark of both HIV-1- and METH-associated neuroinflammation. Significant commonality exists in the neurotoxic mechanisms for both METH and HAND; however, the pathways dysregulated in astroglia during METH exposure are less clear. Thus, this review highlights alterations in astrocyte intracellular signaling pathways, gene expression and function during METH and HIV-1 comorbidity, with special emphasis on HAND-associated neuroinflammation. Importantly, this review carefully evaluates interventions targeting astrocytes in HAND and METH as potential novel therapeutic approaches. This comprehensive overview indicates, without a doubt, that during HIV-1 infection and METH abuse, a complex dialog between all neural cells is orchestrated through astrocyte regulated neuroinflammation.
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Affiliation(s)
- Kathleen Borgmann
- Department of Cell Biology and Immunology, University of North Texas Health Science Center Fort Worth, TX, USA
| | - Anuja Ghorpade
- Department of Cell Biology and Immunology, University of North Texas Health Science Center Fort Worth, TX, USA
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Vigorito M, Connaghan KP, Chang SL. The HIV-1 transgenic rat model of neuroHIV. Brain Behav Immun 2015; 48:336-49. [PMID: 25733103 PMCID: PMC4753047 DOI: 10.1016/j.bbi.2015.02.020] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 02/16/2015] [Accepted: 02/20/2015] [Indexed: 01/28/2023] Open
Abstract
Despite the ability of current combination anti-retroviral therapy (cART) to limit the progression of HIV-1 to AIDS, HIV-positive individuals continue to experience neuroHIV in the form of HIV-associated neurological disorders (HAND), which can range from subtle to substantial neurocognitive impairment. NeuroHIV may also influence substance use, abuse, and dependence in HIV-positive individuals. Because of the nature of the virus, variables such as mental health co-morbidities make it difficult to study the interaction between HIV and substance abuse in human populations. Several rodent models have been developed in an attempt to study the transmission and pathogenesis of the HIV-1 virus. The HIV-1 transgenic (HIV-1Tg) rat is a reliable model of neuroHIV because it mimics the condition of HIV-infected patients on cART. Research using this model supports the hypothesis that the presence of HIV-1 viral proteins in the central nervous system increases the sensitivity and susceptibility of HIV-positive individuals to substance abuse.
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Affiliation(s)
- Michael Vigorito
- Institute of NeuroImmune Pharmacology and Department of Biological Sciences, Seton Hall University, South Orange, NJ, USA
| | - Kaitlyn P Connaghan
- Institute of NeuroImmune Pharmacology and Department of Biological Sciences, Seton Hall University, South Orange, NJ, USA
| | - Sulie L Chang
- Institute of NeuroImmune Pharmacology and Department of Biological Sciences, Seton Hall University, South Orange, NJ, USA.
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Lee KM, MacLean AG. New advances on glial activation in health and disease. World J Virol 2015; 4:42-55. [PMID: 25964871 PMCID: PMC4419121 DOI: 10.5501/wjv.v4.i2.42] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 01/23/2015] [Accepted: 02/11/2015] [Indexed: 02/05/2023] Open
Abstract
In addition to being the support cells of the central nervous system (CNS), astrocytes are now recognized as active players in the regulation of synaptic function, neural repair, and CNS immunity. Astrocytes are among the most structurally complex cells in the brain, and activation of these cells has been shown in a wide spectrum of CNS injuries and diseases. Over the past decade, research has begun to elucidate the role of astrocyte activation and changes in astrocyte morphology in the progression of neural pathologies, which has led to glial-specific interventions for drug development. Future therapies for CNS infection, injury, and neurodegenerative disease are now aimed at targeting astrocyte responses to such insults including astrocyte activation, astrogliosis and other morphological changes, and innate and adaptive immune responses.
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Long noncoding RNA SPRY4-IT1 predicts poor patient prognosis and promotes tumorigenesis in gastric cancer. Tumour Biol 2015; 53:2016-2028. [PMID: 25835973 DOI: 10.1007/s12035-015-9142-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Accepted: 03/12/2015] [Indexed: 12/16/2022] Open
Abstract
Gastric cancer (GC) is the second common cause of cancer-related death worldwide. Long noncoding RNAs (lncRNAs) are emerging as novel regulators in the cancer paradigm. However, investigation of lncRNAs on GC is still in its infancy. In this study, we focused on lncRNA SPRY4 intronic transcript 1 (SPRY4-IT1) and investigated its expression pattern, clinical significance, biological function, and molecular mechanism in GC. SPRY4-IT1 expression was examined, and its correlation with clinicopathological characteristics and patient prognosis was analyzed. A series of assays were performed to understand the role of SPRY4-IT1 in GC. SPRY4-IT1 expression was elevated in GC tissues and cell lines, and SPRY4-IT1 levels were highly positively correlated with tumor size, invasion depth, distant metastasis, TNM stage, and reduced overall survival (OS) and disease-free survival (DFS). A multivariate analysis showed that SPRY4-IT1 expression is an independent prognostic factor of OS and DFS in patients with GC. Additionally, the results of in vitro assays showed that the suppression of SPRY4-IT1 expression in GC cell line MKN-45 significantly reduced cell proliferation, colony formation, and cell migration/invasion. Moreover, the tumorigenic effects of SPRY4-IT1 were partially mediated by the regulation of certain cyclins and matrix metalloproteinases (MMPs)-related genes. Our data suggest that SPRY4-IT1 plays a critical role in GC tumorigenesis and may represent a novel prognostic marker and potential therapeutic target in patients with GC.
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Nookala AR, Kumar A. Molecular mechanisms involved in HIV-1 Tat-mediated induction of IL-6 and IL-8 in astrocytes. J Neuroinflammation 2014; 11:214. [PMID: 25539898 PMCID: PMC4302610 DOI: 10.1186/s12974-014-0214-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 12/03/2014] [Indexed: 01/25/2023] Open
Abstract
Background HIV-associated neurocognitive disorders (HAND) exist in approximately 50% of infected individuals even after the introduction of highly active antiretroviral therapy. HIV-1 Tat has been implicated in HIV-associated neurotoxicity mediated through production of pro-inflammatory cytokines like IL-6 and IL-8 by astrocytes among others as well as oxidative stress. However, the underlying mechanism(s) in the up-regulation of IL-6 and IL-8 are not clearly understood. The present study was designed to determine the mechanism(s) responsible for IL-6 and IL-8 up-regulation by HIV-1 Tat. Methods SVG astrocytes were transiently transfected with a plasmid encoding HIV-1 Tat. The HIV-1 Tat-mediated mRNA and protein expression levels of both IL-6 and IL-8 in SVG astrocytes were quantified using real time RT-PCR and multiplex cytokine assay respectively. We also employed immunocytochemistry for staining of IL-6 and IL-8. The underlying signaling mechanism(s) were identified using pharmacological inhibitors and siRNA for different intermediate steps involved in PI3K/Akt, p38 MAPK and JNK MAPK pathways. Appropriate controls were used in the experiments and the effect of pharmacological antagonists and siRNA were observed on both mRNA expression and protein levels. Results Both IL-6/IL-8 mRNA and protein showed peak expressions at 6 hours and 96 hours post-transfection, respectively. Elevated levels of IL-6/IL-8 were also confirmed by immunocytochemistry. Our studies indicated that both NF-kB and AP-1 transcription factors were involved in IL-6 and IL-8 expression mediated by HIV-1 Tat; however, AP-1 was differentially activated for either cytokine. In the case of IL-6, p38δ activated AP-1 whereas JNK but not p38 MAPK was involved in AP-1 activation for IL-8 production. On the other hand both PI3K/Akt and p38 MAPK (β subunit) were found to be involved in activation of NF-κB that led to IL-6 and IL-8 production. Conclusion Our results demonstrate HIV-1 Tat-mediated induction of both IL-6 and IL-8 in a time-dependent manner in SVG astrocytes. Furthermore, we also showed the involvement of NF-κB and AP-1 transcription factors regulated by PI3/Akt, p38 MAPK and JNK MAPK upstream signaling molecules. These results present new therapeutic targets that could be used in management of HAND. Electronic supplementary material The online version of this article (doi:10.1186/s12974-014-0214-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anantha Ram Nookala
- Division of Pharmacology and Toxicology, UMKC-School of Pharmacy, 2464 Charlotte Street, Kansas City, MO, 64108, USA.
| | - Anil Kumar
- Division of Pharmacology and Toxicology, UMKC-School of Pharmacy, 2464 Charlotte Street, Kansas City, MO, 64108, USA.
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