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Yadav-Samudrala BJ, Dodson H, Ramineni S, Kim E, Poklis JL, Lu D, Ignatowska-Jankowska BM, Lichtman AH, Fitting S. Cannabinoid receptor 1 positive allosteric modulator ZCZ011 shows differential effects on behavior and the endocannabinoid system in HIV-1 Tat transgenic female and male mice. PLoS One 2024; 19:e0305868. [PMID: 38913661 PMCID: PMC11195999 DOI: 10.1371/journal.pone.0305868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 06/05/2024] [Indexed: 06/26/2024] Open
Abstract
The cannabinoid receptor type 1 (CB1R) is a promising therapeutic target for various neurodegenerative diseases, including HIV-1-associated neurocognitive disorder (HAND). However, the therapeutic potential of CB1R by direct activation is limited due to its psychoactive side effects. Therefore, research has focused on indirectly activating the CB1R by utilizing positive allosteric modulators (PAMs). Studies have shown that CB1R PAMs (ZCZ011 and GAT211) are effective in mouse models of Huntington's disease and neuropathic pain, and hence, we assess the therapeutic potential of ZCZ011 in a well-established mouse model of neuroHIV. The current study investigates the effect of chronic ZCZ011 treatment (14 days) on various behavioral paradigms and the endocannabinoid system in HIV-1 Tat transgenic female and male mice. Chronic ZCZ011 treatment (10 mg/kg) did not alter body mass, locomotor activity, or anxiety-like behavior regardless of sex or genotype. However, differential effects were noted in hot plate latency, motor coordination, and recognition memory in female mice only, with ZCZ011 treatment increasing hot plate latency and improving motor coordination and recognition memory. Only minor effects or no alterations were seen in the endocannabinoid system and related lipids except in the cerebellum, where the effect of ZCZ011 was more pronounced in female mice. Moreover, AEA and PEA levels in the cerebellum were positively correlated with improved motor coordination in female mice. In summary, these findings indicate that chronic ZCZ011 treatment has differential effects on antinociception, motor coordination, and memory, based on sex and HIV-1 Tat expression, making CB1R PAMs potential treatment options for HAND without the psychoactive side effects.
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Affiliation(s)
- Barkha J. Yadav-Samudrala
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Hailey Dodson
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Shreya Ramineni
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Elizabeth Kim
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Justin L. Poklis
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Dai Lu
- Department of Pharmaceutical Sciences, Texas A&M, College Station, Texas, United States of America
| | | | - Aron H. Lichtman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Sylvia Fitting
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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2
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Xu C, Yadav-Samudrala BJ, Xu C, Nath B, Mistry T, Jiang W, Niphakis MJ, Cravatt BF, Mukhopadhyay S, Lichtman AH, Ignatowska-Jankowska BM, Fitting S. Inhibitory Neurotransmission Is Sex-Dependently Affected by Tat Expression in Transgenic Mice and Suppressed by the Fatty Acid Amide Hydrolase Enzyme Inhibitor PF3845 via Cannabinoid Type-1 Receptor Mechanisms. Cells 2022; 11:857. [PMID: 35269478 PMCID: PMC8909692 DOI: 10.3390/cells11050857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/14/2022] [Accepted: 02/23/2022] [Indexed: 11/21/2022] Open
Abstract
(1) Background. The endocannabinoid (eCB) system, which regulates physiological and cognitive processes, presents a promising therapeutic target for treating HIV-associated neurocognitive disorders (HAND). Here we examine whether upregulating eCB tone has potential protective effects against HIV-1 Tat (a key HIV transactivator of transcription) protein-induced alterations in synaptic activity. (2) Methods. Whole-cell patch-clamp recordings were performed to assess inhibitory GABAergic neurotransmission in prefrontal cortex slices of Tat transgenic male and female mice, in the presence and absence of the fatty acid amide hydrolase (FAAH) enzyme inhibitor PF3845. Western blot and mass spectrometry analyses assessed alterations of cannabinoid receptor and enzyme protein expression as well as endogenous ligands, respectively, to determine the impact of Tat exposure on the eCB system. (3) Results. GABAergic activity was significantly altered upon Tat exposure based on sex, whereas the effectiveness of PF3845 to suppress GABAergic activity in Tat transgenic mice was not altered by Tat or sex and involved CB1R-related mechanisms that depended on calcium signaling. Additionally, our data indicated sex-dependent changes for AEA and related non-eCB lipids based on Tat induction. (4) Conclusion. Results highlight sex- and/or Tat-dependent alterations of GABAergic activity and eCB signaling in the prefrontal cortex of Tat transgenic mice and further increase our understanding about the role of FAAH inhibition in neuroHIV.
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Affiliation(s)
- Changqing Xu
- Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (C.X.); (B.J.Y.-S.); (C.X.)
| | - Barkha J. Yadav-Samudrala
- Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (C.X.); (B.J.Y.-S.); (C.X.)
| | - Callie Xu
- Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (C.X.); (B.J.Y.-S.); (C.X.)
| | - Bhupendra Nath
- Department of Chemistry & Biochemistry, North Carolina Central University, Durham, NC 27707, USA; (B.N.); (T.M.); (S.M.)
| | - Twisha Mistry
- Department of Chemistry & Biochemistry, North Carolina Central University, Durham, NC 27707, USA; (B.N.); (T.M.); (S.M.)
| | - Wei Jiang
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 29425, USA;
- Division of Infectious Diseases, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Micah J. Niphakis
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037, USA; (M.J.N.); (B.F.C.)
| | - Benjamin F. Cravatt
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037, USA; (M.J.N.); (B.F.C.)
| | - Somnath Mukhopadhyay
- Department of Chemistry & Biochemistry, North Carolina Central University, Durham, NC 27707, USA; (B.N.); (T.M.); (S.M.)
| | - Aron H. Lichtman
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA;
| | | | - Sylvia Fitting
- Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (C.X.); (B.J.Y.-S.); (C.X.)
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3
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Sokolova IV, Szucs A, Sanna PP. Reduced intrinsic excitability of CA1 pyramidal neurons in human immunodeficiency virus (HIV) transgenic rats. Brain Res 2019; 1724:146431. [PMID: 31491420 PMCID: PMC6939992 DOI: 10.1016/j.brainres.2019.146431] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/24/2019] [Accepted: 08/30/2019] [Indexed: 10/26/2022]
Abstract
The hippocampus is involved in key neuronal circuits that underlie cognition, memory, and anxiety, and it is increasingly recognized as a vulnerable structure that contributes to the pathogenesis of HIV-associated neurocognitive disorder (HAND). However, the mechanisms responsible for hippocampal dysfunction in neuroHIV remain unknown. The present study used HIV transgenic (Tg) rats and patch-clamp electrophysiological techniques to study the effects of the chronic low-level expression of HIV proteins on hippocampal CA1 pyramidal neurons. The dorsal and ventral areas of the hippocampus are involved in different neurocircuits and thus were evaluated separately. We found a significant decrease in the intrinsic excitability of CA1 neurons in the dorsal hippocampus in HIV Tg rats by comparing neuronal spiking induced by current step injections and by dynamic clamp to simulate neuronal spiking activity. The decrease in excitability in the dorsal hippocampus was accompanied by a higher rate of excitatory postsynaptic currents (EPSCs), whereas CA1 pyramidal neurons in the ventral hippocampus in HIV Tg rats had higher EPSC amplitudes. We also observed a reduction of hyperpolarization-activated nonspecific cationic current (Ih) in both the dorsal and ventral hippocampus. Neurotoxic HIV proteins have been shown to increase neuronal excitation. The lower excitability of CA1 pyramidal neurons that was observed herein may represent maladaptive homeostatic plasticity that seeks to stabilize baseline neuronal firing activity but may disrupt neural network function and contribute to HIV-associated neuropsychological disorders, such as HAND and depression.
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Affiliation(s)
- Irina V Sokolova
- The Scripps Research Institute, Department of Immunology and Microbiology, 10550 North Torrey Pines Road, La Jolla, CA 92037-1000, United States
| | - Attila Szucs
- The Scripps Research Institute, Department of Immunology and Microbiology, 10550 North Torrey Pines Road, La Jolla, CA 92037-1000, United States; University of California, San Diego, BioCircuits Institute, 9500 Gilman Drive, La Jolla, CA 92039-0328, United States; MTA-ELTE-NAP B Neuronal Cell Biology Research Group, Eötvös Lóránd University, Budapest, Hungary
| | - Pietro Paolo Sanna
- The Scripps Research Institute, Department of Immunology and Microbiology, 10550 North Torrey Pines Road, La Jolla, CA 92037-1000, United States.
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4
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Wenzel ED, Avdoshina V, Mocchetti I. HIV-associated neurodegeneration: exploitation of the neuronal cytoskeleton. J Neurovirol 2019; 25:301-312. [PMID: 30850975 DOI: 10.1007/s13365-019-00737-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/16/2019] [Accepted: 02/18/2019] [Indexed: 01/23/2023]
Abstract
Human immunodeficiency virus-1 (HIV) infection of the central nervous system damages synapses and promotes axonal injury, ultimately resulting in HIV-associated neurocognitive disorders (HAND). The mechanisms through which HIV causes damage to neurons are still under investigation. The cytoskeleton and associated proteins are fundamental for axonal and dendritic integrity. In this article, we review evidence that HIV proteins, such as the envelope protein gp120 and transactivator of transcription (Tat), impair the structure and function of the neuronal cytoskeleton. Investigation into the effects of viral proteins on the neuronal cytoskeleton may provide a better understanding of HIV neurotoxicity and suggest new avenues for additional therapies.
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Affiliation(s)
- Erin D Wenzel
- Department of Pharmacology & Physiology, Georgetown University Medical Center, 3970 Reservoir Rd NW, Washington, DC, 20057, USA
| | - Valeria Avdoshina
- Department of Neuroscience, Georgetown University Medical Center, 3970 Reservoir Rd NW, Washington, DC, 20057, USA
| | - Italo Mocchetti
- Department of Pharmacology & Physiology, Georgetown University Medical Center, 3970 Reservoir Rd NW, Washington, DC, 20057, USA. .,Department of Neuroscience, Georgetown University Medical Center, 3970 Reservoir Rd NW, Washington, DC, 20057, USA.
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5
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Hermes DJ, Xu C, Poklis JL, Niphakis MJ, Cravatt BF, Mackie K, Lichtman AH, Ignatowska-Jankowska BM, Fitting S. Neuroprotective effects of fatty acid amide hydrolase catabolic enzyme inhibition in a HIV-1 Tat model of neuroAIDS. Neuropharmacology 2018; 141:55-65. [PMID: 30114402 DOI: 10.1016/j.neuropharm.2018.08.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 07/20/2018] [Accepted: 08/12/2018] [Indexed: 12/16/2022]
Abstract
The HIV-1 transactivator of transcription (Tat) is a neurotoxin involved in the pathogenesis of HIV-1 associated neurocognitive disorders (HAND). The neurotoxic effects of Tat are mediated directly via AMPA/NMDA receptor activity and indirectly through neuroinflammatory signaling in glia. Emerging strategies in the development of neuroprotective agents involve the modulation of the endocannabinoid system. A major endocannabinoid, anandamide (N-arachidonoylethanolamine, AEA), is metabolized by fatty acid amide hydrolase (FAAH). Here we demonstrate using a murine prefrontal cortex primary culture model that the inhibition of FAAH, using PF3845, attenuates Tat-mediated increases in intracellular calcium, neuronal death, and dendritic degeneration via cannabinoid receptors (CB1R and CB2R). Live cell imaging was used to assess Tat-mediated increases in [Ca2+]i, which was significantly reduced by PF3845. A time-lapse assay revealed that Tat potentiates cell death while PF3845 blocks this effect. Additionally PF3845 blocked the Tat-mediated increase in activated caspase-3 (apoptotic marker) positive neurons. Dendritic degeneration was characterized by analyzing stained dendritic processes using Imaris and Tat was found to significantly decrease the size of processes while PF3845 inhibited this effect. Incubation with CB1R and CB2R antagonists (SR141716A and AM630) revealed that PF3845-mediated calcium effects were dependent on CB1R, while reduced neuronal death and degeneration was CB2R-mediated. PF3845 application led to increased levels of AEA, suggesting the observed effects are likely a result of increased endocannabinoid signaling at CB1R/CB2R. Our findings suggest that modulation of the endogenous cannabinoid system through inhibition of FAAH may be beneficial in treatment of HAND.
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Affiliation(s)
- Douglas J Hermes
- Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Changqing Xu
- Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Justin L Poklis
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Micah J Niphakis
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037, USA
| | - Benjamin F Cravatt
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ken Mackie
- Department of Psychological & Brain Science, Indiana University Bloomington, Bloomington, IN 47405, USA
| | - Aron H Lichtman
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | | | - Sylvia Fitting
- Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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6
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Nookala AR, Schwartz DC, Chaudhari NS, Glazyrin A, Stephens EB, Berman NEJ, Kumar A. Methamphetamine augment HIV-1 Tat mediated memory deficits by altering the expression of synaptic proteins and neurotrophic factors. Brain Behav Immun 2018; 71:37-51. [PMID: 29729322 PMCID: PMC6003882 DOI: 10.1016/j.bbi.2018.04.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Revised: 04/29/2018] [Accepted: 04/30/2018] [Indexed: 01/06/2023] Open
Abstract
Methamphetamine (METH) abuse is common among individuals infected with HIV-1 and has been shown to affect HIV replication and pathogenesis. These HIV-1 infected individuals also exhibit greater neuronal injury and higher cognitive decline. HIV-1 proteins, specifically gp120 and HIV-1 Tat, have been earlier shown to affect neurocognition. HIV-1 Tat, a viral protein released early during HIV-1 replication, contributes to HIV-associated neurotoxicity through various mechanisms including production of pro-inflammatory cytokines, reactive oxygen species and dysregulation of neuroplasticity. However, the combined effect of METH and HIV-1 Tat on neurocognition and its potential effect on neuroplasticity mechanisms remains largely unknown. Therefore, the present study was undertaken to investigate the combined effect of METH and HIV-1 Tat on behavior and on the expression of neuroplasticity markers by utilizing Doxycycline (DOX)-inducible HIV-1 Tat (1-86) transgenic mice. Expression of Tat in various brain regions of these mice was confirmed by RT-PCR. The mice were administered with an escalating dose of METH (0.1 mg/kg to 6 mg/kg, i.p) over a 7-day period, followed by 6 mg/kg, i.p METH twice a day for four weeks. After three weeks of METH administration, Y maze and Morris water maze assays were performed to determine the effect of Tat and METH on working and spatial memory, respectively. Compared with controls, working memory was significantly decreased in Tat mice that were administered METH. Moreover, significant deficits in spatial memory were also observed in Tat-Tg mice that were administered METH. A significant reduction in the protein expressions of synapsin 1, synaptophysin, Arg3.1, PSD-95, and BDNF in different brain regions were also observed. Expression levels of Calmodulin kinase II (CaMKII), a marker of synaptodendritic integrity, were also significantly decreased in HIV-1 Tat mice that were treated with METH. Together, this data suggests that METH enhances HIV-1 Tat-induced memory deficits by reducing the expression of pre- and postsynaptic proteins and neuroplasticity markers, thus providing novel insights into the molecular mechanisms behind neurocognitive impairments in HIV-infected amphetamine users.
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Affiliation(s)
- Anantha Ram Nookala
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO, 64108, USA
| | - Daniel C. Schwartz
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO, 64108, USA
| | - Nitish S. Chaudhari
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO, 64108, USA
| | - Alexy Glazyrin
- Department of Pathology, School of Medicine, School of Medicine, University of Missouri-Kansas City, Kansas City, MO, 64108, USA
| | - Edward B. Stephens
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Nancy E. J. Berman
- Department of Anatomy and Cell biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Anil Kumar
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO, 64108, USA.
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7
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Francesconi W, Berton F, Marcondes MCG. HIV-1 Tat alters neuronal intrinsic excitability. BMC Res Notes 2018; 11:275. [PMID: 29728138 PMCID: PMC5935945 DOI: 10.1186/s13104-018-3376-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 04/21/2018] [Indexed: 12/20/2022] Open
Abstract
Objective In HIV+ individuals, the virus enters the central nervous system and invades innate immune cells, producing important changes that result in neurological deficits. We aimed to determine whether HIV plays a direct role in neuronal excitability. Of the HIV peptides, Tat is secreted and acts in other cells. In order to examine whether the HIV Tat can modify neuronal excitability, we exposed primary murine hippocampal neurons to that peptide, and tested its effects on the intrinsic membrane properties, 4 and 24 h after exposure. Results The exposure of hippocampal pyramidal neurons to Tat for 4 h did not alter intrinsic membrane properties. However, we found a strong increase in intrinsic excitability, characterized by increase of the slope (Gain) of the input–output function, in cells treated with Tat for 24 h. Nevertheless, Tat treatment for 24 h did not alter the resting membrane potential, input resistance, rheobase and action potential threshold. Thus, neuronal adaptability to Tat exposure for 24 h is not applicable to basic neuronal properties. A restricted but significant effect on coupling the inputs to the outputs may have implications to our knowledge of Tat biophysical firing capability, and its involvement in neuronal hyperexcitability in neuroHIV.
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Affiliation(s)
- Walter Francesconi
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, 6068 COMRB MC 512, Chicago, IL, 60612, USA. .,The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA, 92037, USA.
| | - Fulvia Berton
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, 6068 COMRB MC 512, Chicago, IL, 60612, USA.,The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA, 92037, USA
| | - Maria Cecilia G Marcondes
- San Diego Biomedical Research Institute, 10865 Road to the Cure, San Diego, CA, 92121, USA. .,The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA, 92037, USA.
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8
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Gaskill PJ, Miller DR, Gamble-George J, Yano H, Khoshbouei H. HIV, Tat and dopamine transmission. Neurobiol Dis 2017; 105:51-73. [PMID: 28457951 PMCID: PMC5541386 DOI: 10.1016/j.nbd.2017.04.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 04/04/2017] [Accepted: 04/16/2017] [Indexed: 01/02/2023] Open
Abstract
Human Immunodeficiency Virus (HIV) is a progressive infection that targets the immune system, affecting more than 37 million people around the world. While combinatorial antiretroviral therapy (cART) has lowered mortality rates and improved quality of life in infected individuals, the prevalence of HIV associated neurocognitive disorders is increasing and HIV associated cognitive decline remains prevalent. Recent research has suggested that HIV accessory proteins may be involved in this decline, and several studies have indicated that the HIV protein transactivator of transcription (Tat) can disrupt normal neuronal and glial function. Specifically, data indicate that Tat may directly impact dopaminergic neurotransmission, by modulating the function of the dopamine transporter and specifically damaging dopamine-rich regions of the CNS. HIV infection of the CNS has long been associated with dopaminergic dysfunction, but the mechanisms remain undefined. The specific effect(s) of Tat on dopaminergic neurotransmission may be, at least partially, a mechanism by which HIV infection directly or indirectly induces dopaminergic dysfunction. Therefore, precisely defining the specific effects of Tat on the dopaminergic system will help to elucidate the mechanisms by which HIV infection of the CNS induces neuropsychiatric, neurocognitive and neurological disorders that involve dopaminergic neurotransmission. Further, this will provide a discussion of the experiments needed to further these investigations, and may help to identify or develop new therapeutic approaches for the prevention or treatment of these disorders in HIV-infected individuals.
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Affiliation(s)
- Peter J Gaskill
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, United States.
| | - Douglas R Miller
- Department of Neuroscience, University of Florida, Gainesville, FL 32611, United States
| | - Joyonna Gamble-George
- Department of Neuroscience, University of Florida, Gainesville, FL 32611, United States
| | - Hideaki Yano
- National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, United States
| | - Habibeh Khoshbouei
- Department of Neuroscience, University of Florida, Gainesville, FL 32611, United States.
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9
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Nedelcovych MT, Tenora L, Kim BH, Kelschenbach J, Chao W, Hadas E, Jančařík A, Prchalová E, Zimmermann SC, Dash RP, Gadiano AJ, Garrett C, Furtmüller G, Oh B, Brandacher G, Alt J, Majer P, Volsky DJ, Rais R, Slusher BS. N-(Pivaloyloxy)alkoxy-carbonyl Prodrugs of the Glutamine Antagonist 6-Diazo-5-oxo-l-norleucine (DON) as a Potential Treatment for HIV Associated Neurocognitive Disorders. J Med Chem 2017; 60:7186-7198. [PMID: 28759224 DOI: 10.1021/acs.jmedchem.7b00966] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Aberrant excitatory neurotransmission associated with overproduction of glutamate has been implicated in the development of HIV-associated neurocognitive disorders (HAND). The glutamine antagonist 6-diazo-5-oxo-l-norleucine (DON, 14) attenuates glutamate synthesis in HIV-infected microglia/macrophages, offering therapeutic potential for HAND. We show that 14 prevents manifestation of spatial memory deficits in chimeric EcoHIV-infected mice, a model of HAND. 14 is not clinically available, however, because its development was hampered by peripheral toxicities. We describe the synthesis of several substituted N-(pivaloyloxy)alkoxy-carbonyl prodrugs of 14 designed to circulate inert in plasma and be taken up and biotransformed to 14 in the brain. The lead prodrug, isopropyl 6-diazo-5-oxo-2-(((phenyl(pivaloyloxy)methoxy)carbonyl)amino)hexanoate (13d), was stable in swine and human plasma but liberated 14 in swine brain homogenate. When dosed systemically in swine, 13d provided a 15-fold enhanced CSF-to-plasma ratio and a 9-fold enhanced brain-to-plasma ratio relative to 14, opening a possible clinical path for the treatment of HAND.
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Affiliation(s)
| | - Lukáš Tenora
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic vvi , 166 10 Prague, Czech Republic
| | - Boe-Hyun Kim
- Department of Medicine, Icahn School of Medicine at Mount Sinai , New York, New York 10029, United States
| | - Jennifer Kelschenbach
- Department of Medicine, Icahn School of Medicine at Mount Sinai , New York, New York 10029, United States
| | - Wei Chao
- Department of Medicine, Icahn School of Medicine at Mount Sinai , New York, New York 10029, United States
| | - Eran Hadas
- Department of Medicine, Icahn School of Medicine at Mount Sinai , New York, New York 10029, United States
| | - Andrej Jančařík
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic vvi , 166 10 Prague, Czech Republic
| | - Eva Prchalová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic vvi , 166 10 Prague, Czech Republic
| | | | | | | | | | | | | | | | | | - Pavel Majer
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic vvi , 166 10 Prague, Czech Republic
| | - David J Volsky
- Department of Medicine, Icahn School of Medicine at Mount Sinai , New York, New York 10029, United States
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10
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Marks WD, Paris JJ, Schier CJ, Denton MD, Fitting S, McQuiston AR, Knapp PE, Hauser KF. HIV-1 Tat causes cognitive deficits and selective loss of parvalbumin, somatostatin, and neuronal nitric oxide synthase expressing hippocampal CA1 interneuron subpopulations. J Neurovirol 2016; 22:747-762. [PMID: 27178324 PMCID: PMC5107352 DOI: 10.1007/s13365-016-0447-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 04/02/2016] [Accepted: 04/10/2016] [Indexed: 02/08/2023]
Abstract
Memory deficits are characteristic of HIV-associated neurocognitive disorders (HAND) and co-occur with hippocampal pathology. The HIV-1 transactivator of transcription (Tat), a regulatory protein, plays a significant role in these events, but the cellular mechanisms involved are poorly understood. Within the hippocampus, diverse populations of interneurons form complex networks; even subtle disruptions can drastically alter synaptic output, resulting in behavioral dysfunction. We hypothesized that HIV-1 Tat would impair cognitive behavior and injure specific hippocampal interneuron subtypes. Male transgenic mice that inducibly expressed HIV-1 Tat (or non-expressing controls) were assessed for cognitive behavior or had hippocampal CA1 subregions evaluated via interneuron subpopulation markers. Tat exposure decreased spatial memory in a Barnes maze and mnemonic performance in a novel object recognition test. Tat reduced the percentage of neurons expressing neuronal nitric oxide synthase (nNOS) without neuropeptide Y immunoreactivity in the stratum pyramidale and the stratum radiatum, parvalbumin in the stratum pyramidale, and somatostatin in the stratum oriens, which are consistent with reductions in interneuron-specific interneuron type 3 (IS3), bistratified, and oriens-lacunosum-moleculare interneurons, respectively. The findings reveal that an interconnected ensemble of CA1 nNOS-expressing interneurons, the IS3 cells, as well as subpopulations of parvalbumin- and somatostatin-expressing interneurons are preferentially vulnerable to HIV-1 Tat. Importantly, the susceptible interneurons form a microcircuit thought to be involved in feedback inhibition of CA1 pyramidal cells and gating of CA1 pyramidal cell inputs. The identification of vulnerable CA1 hippocampal interneurons may provide novel insight into the basic mechanisms underlying key functional and neurobehavioral deficits associated with HAND.
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Affiliation(s)
- William D Marks
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298-0613, USA
| | - Jason J Paris
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298-0613, USA
| | - Christina J Schier
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298-0613, USA
| | - Melissa D Denton
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298-0613, USA
| | - Sylvia Fitting
- Department of Psychology & Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3270, USA
| | - A Rory McQuiston
- Department of Anatomy & Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0709, USA
| | - Pamela E Knapp
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298-0613, USA
- Department of Anatomy & Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0709, USA
- Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, 23298-0059, USA
| | - Kurt F Hauser
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Kontos Medical Sciences Building, 1217 East Marshall Street, Richmond, VA, 23298-0613, USA.
- Department of Anatomy & Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298-0709, USA.
- Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, 23298-0059, USA.
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11
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Xu C, Fitting S. Inhibition of GABAergic Neurotransmission by HIV-1 Tat and Opioid Treatment in the Striatum Involves μ-Opioid Receptors. Front Neurosci 2016; 10:497. [PMID: 27877102 PMCID: PMC5099255 DOI: 10.3389/fnins.2016.00497] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 10/17/2016] [Indexed: 01/07/2023] Open
Abstract
Due to combined antiretroviral therapy (cART), human immunodeficiency virus type 1 (HIV-1) is considered a chronic disease with high prevalence of mild forms of neurocognitive impairments, also referred to as HIV-associated neurocognitive disorders (HAND). Although opiate drug use can exacerbate HIV-1 Tat-induced neuronal damage, it remains unknown how and to what extent opioids interact with Tat on the GABAergic system. We conducted whole-cell recordings in mouse striatal slices and examined the effects of HIV-1 Tat in the presence and absence of morphine (1 μM) and damgo (1 μM) on GABAergic neurotransmission. Results indicated a decrease in the frequency and amplitude of spontaneous inhibitory postsynaptic currents (sIPSCs) and miniature IPSCs (mIPSCs) by Tat (5–50 nM) in a concentration-dependent manner. The significant Tat-induced decrease in IPSCs was abolished when removing extracellular and/or intracellular calcium. Treatment with morphine or damgo alone significantly decreased the frequency, but not amplitude of IPSCs. Interestingly, morphine but not damgo indicated an additional downregulation of the mean frequency of mIPSCs in combination with Tat. Pretreatment with naloxone (1 μM) and CTAP (1 μM) prevented the Tat-induced decrease in sIPSCs frequency but only naloxone prevented the combined Tat and morphine effect on mIPSCs frequency. Results indicate a Tat- or opioid-induced decrease in GABAergic neurotransmission via μ-opioid receptors with combined Tat and morphine effects involving additional opioid receptor-related mechanisms. Exploring the interactions between Tat and opioids on the GABAergic system may help to guide future research on HAND in the context of opiate drug use.
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Affiliation(s)
- Changqing Xu
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill Chapel Hill, NC, USA
| | - Sylvia Fitting
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill Chapel Hill, NC, USA
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12
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Ambegaokar SS, Kolson DL. Heme oxygenase-1 dysregulation in the brain: implications for HIV-associated neurocognitive disorders. Curr HIV Res 2015; 12:174-88. [PMID: 24862327 PMCID: PMC4155834 DOI: 10.2174/1570162x12666140526122709] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 01/20/2014] [Accepted: 01/27/2014] [Indexed: 12/17/2022]
Abstract
Heme oxygenase-1 (HO-1) is a highly inducible and ubiquitous cellular enzyme that subserves cytoprotective responses to toxic insults, including inflammation and oxidative stress. In neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease and multiple sclerosis, HO-1 expression is increased, presumably reflecting an endogenous neuroprotective response against ongoing cellular injury. In contrast, we have found that in human immunodeficiency virus (HIV) infection of the brain, which is also associated with inflammation, oxidative stress and neurodegeneration, HO-1 expression is decreased, likely reflecting a unique role for HO-1 deficiency in neurodegeneration pathways activated by HIV infection. We have also shown that HO-1 expression is significantly suppressed by HIV replication in cultured macrophages which represent the primary cellular reservoir for HIV in the brain. HO-1 deficiency is associated with release of neurotoxic levels of glutamate from both HIV-infected and immune-activated macrophages; this glutamate-mediated neurotoxicity is suppressed by pharmacological induction of HO-1 expression in the macrophages. Thus, HO-1 induction could be a therapeutic strategy for neuroprotection against HIV infection and other neuroinflammatory brain diseases. Here, we review various stimuli and signaling pathways regulating HO-1 expression in macrophages, which could promote neuronal survival through HO-1-modulation of endogenous antioxidant and immune modulatory pathways, thus limiting the oxidative stress that can promote HIV disease progression in the CNS. The use of pharmacological inducers of endogenous HO-1 expression as potential adjunctive neuroprotective therapeutics in HIV infection is also discussed.
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Affiliation(s)
| | - Dennis L Kolson
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, 280 Clinical Research Building, 415 Curie Blvd., Philadelphia, PA 19104, USA.
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13
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Increased excitability in tat-transgenic mice: Role of tat in HIV-related neurological disorders. Neurobiol Dis 2013; 55:110-9. [DOI: 10.1016/j.nbd.2013.02.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 02/03/2013] [Accepted: 02/19/2013] [Indexed: 11/20/2022] Open
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14
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Carey AN, Liu X, Mintzopoulos D, Paris JJ, Muschamp JW, McLaughlin JP, Kaufman MJ. Conditional Tat protein expression in the GT-tg bigenic mouse brain induces gray matter density reductions. Prog Neuropsychopharmacol Biol Psychiatry 2013; 43:49-54. [PMID: 23269344 PMCID: PMC3612135 DOI: 10.1016/j.pnpbp.2012.12.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 12/04/2012] [Accepted: 12/19/2012] [Indexed: 12/14/2022]
Abstract
Tat (Trans-activator of transcription) is implicated in the neuropathogenesis of HIV-1 infection and known to contribute to neuronal damage and learning and memory impairments. However, direct neuroanatomical demonstration of Tat pathobiology is limited. GT-tg bigenic mice with a doxycycline (Dox)-inducible and brain-selective tat gene were used to test the hypothesis that conditional induction of Tat activity in brain can induce gray matter density abnormalities. Ultra high spatial resolution ex vivo magnetic resonance imaging (MRI) combined with a voxel based morphometry (VBM) analysis revealed gray matter density reductions in the sublenticular extended amygdala, the amygdala, the amygdala-hippocampal area, piriform and peri-/entorhinal cortices, and hypothalamus, in Tat-expressing GT-tg mice compared to Dox-treated C57Bl/6J mice. These neuroanatomical abnormalities are consistent with regions expected to be abnormal based on behavioral deficits exhibited by Tat-expressing mice (Carey et al., 2012). These experiments provide the first neuroimaging evidence that conditional Tat protein expression in the GT-tg bigenic mouse model alters brain structure. The findings warrant future studies to further characterize effects of conditional Tat expression on brain structure. Such studies may improve our understanding of the neurological underpinnings of neuroAIDS and the neurodegeneration associated with HIV-1 infection, potentially leading to new treatments.
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Affiliation(s)
- Amanda N. Carey
- Northeastern University, Department of Psychology, Boston, Massachusetts 02115, USA,Simmons College, Department of Psychology, Boston, MA 02115, USA
| | - Xiaoxu Liu
- McLean Imaging Center, McLean Hospital, Belmont, Massachusetts 02478, USA
| | | | - Jason J. Paris
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida 34987, USA
| | - John W. Muschamp
- McLean Imaging Center, McLean Hospital, Belmont, Massachusetts 02478, USA
| | - Jay P. McLaughlin
- Northeastern University, Department of Psychology, Boston, Massachusetts 02115, USA,Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida 34987, USA
| | - Marc J. Kaufman
- McLean Imaging Center, McLean Hospital, Belmont, Massachusetts 02478, USA,Corresponding author: Dr. Marc J. Kaufman, McLean Imaging Center, McLean Hospital, 115 Mill St., Belmont, MA 02478 USA, Phone: (617)-855-3469, Fax: (617) 855-2770,
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15
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Fitting S, Ignatowska-Jankowska BM, Bull C, Skoff RP, Lichtman AH, Wise LE, Fox MA, Su J, Medina AE, Krahe TE, Knapp PE, Guido W, Hauser KF. Synaptic dysfunction in the hippocampus accompanies learning and memory deficits in human immunodeficiency virus type-1 Tat transgenic mice. Biol Psychiatry 2013; 73:443-53. [PMID: 23218253 PMCID: PMC3570635 DOI: 10.1016/j.biopsych.2012.09.026] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 09/24/2012] [Accepted: 09/25/2012] [Indexed: 12/17/2022]
Abstract
BACKGROUND Human immunodeficiency virus (HIV) associated neurocognitive disorders (HAND), including memory dysfunction, continue to be a major clinical manifestation of HIV type-1 infection. Viral proteins released by infected glia are thought to be the principal triggers of inflammation and bystander neuronal injury and death, thereby driving key symptomatology of HAND. METHODS We used a glial fibrillary acidic protein-driven, doxycycline-inducible HIV type-1 transactivator of transcription (Tat) transgenic mouse model and examined structure-function relationships in hippocampal pyramidal cornu ammonis 1 (CA1) neurons using morphologic, electrophysiological (long-term potentiation [LTP]), and behavioral (Morris water maze, fear-conditioning) approaches. RESULTS Tat induction caused a variety of different inclusions in astrocytes characteristic of lysosomes, autophagic vacuoles, and lamellar bodies, which were typically present within distal cytoplasmic processes. In pyramidal CA1 neurons, Tat induction reduced the number of apical dendritic spines, while disrupting the distribution of synaptic proteins (synaptotagmin 2 and gephyrin) associated with inhibitory transmission but with minimal dendritic pathology and no evidence of pyramidal neuron death. Electrophysiological assessment of excitatory postsynaptic field potential at Schaffer collateral/commissural fiber-CA1 synapses showed near total suppression of LTP in mice expressing Tat. The loss in LTP coincided with disruptions in learning and memory. CONCLUSIONS Tat expression in the brain results in profound functional changes in synaptic physiology and in behavior that are accompanied by only modest structural changes and minimal pathology. Tat likely contributes to HAND by causing molecular changes that disrupt synaptic organization, with inhibitory presynaptic terminals containing synaptotagmin 2 appearing especially vulnerable.
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Affiliation(s)
- Sylvia Fitting
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, Virginia 23298, USA.
| | - Bogna M. Ignatowska-Jankowska
- Departments of Pharmacology & Toxicology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
| | - Cecilia Bull
- Anatomy & Neurobiology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
| | - Robert P. Skoff
- Department of Anatomy & Cell Biology, Wayne State University, School of Medicine, Detroit, MI 48202
| | - Aron H. Lichtman
- Departments of Pharmacology & Toxicology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
,Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
| | - Laura E. Wise
- Departments of Pharmacology & Toxicology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
| | - Michael A. Fox
- Anatomy & Neurobiology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
| | - Jianmin Su
- Anatomy & Neurobiology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
| | - Alexandre E. Medina
- Anatomy & Neurobiology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
| | - Thomas E. Krahe
- Anatomy & Neurobiology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
| | - Pamela E. Knapp
- Departments of Pharmacology & Toxicology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
,Anatomy & Neurobiology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
,Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
| | - William Guido
- Anatomy & Neurobiology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
| | - Kurt F. Hauser
- Departments of Pharmacology & Toxicology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
,Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23289
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16
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Carey AN, Sypek EI, Singh HD, Kaufman MJ, McLaughlin JP. Expression of HIV-Tat protein is associated with learning and memory deficits in the mouse. Behav Brain Res 2011; 229:48-56. [PMID: 22197678 DOI: 10.1016/j.bbr.2011.12.019] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 12/05/2011] [Accepted: 12/11/2011] [Indexed: 01/10/2023]
Abstract
HIV-Tat protein has been implicated in the pathogenesis of HIV-1 neurological complications (i.e., neuroAIDS), but direct demonstrations of the effects of Tat on behavior are limited. GT-tg mice with a doxycycline (Dox)-inducible and brain-selective tat gene coding for Tat protein were used to test the hypothesis that the activity of Tat in brain is sufficient to impair learning and memory processes. Western blot analysis of GT-tg mouse brains demonstrated an increase in Tat antibody labeling that seemed to be dependent on the dose and duration of Dox pretreatment. Dox-treated GT-tg mice tested in the Barnes maze demonstrated longer latencies to find an escape hole and displayed deficits in probe trial performance versus uninduced GT-tg littermates, suggesting Tat-induced impairments of spatial learning and memory. Reversal learning was also impaired in Tat-induced mice. Tat-induced mice additionally demonstrated long-lasting (up to one month) deficiencies in novel object recognition learning and memory performance. Furthermore, novel object recognition impairment was dependent on the dose and duration of Dox exposure, suggesting that Tat exposure progressively mediated deficits. These experiments provide evidence that Tat protein expression is sufficient to mediate cognitive abnormalities seen in HIV-infected individuals. Moreover, the genetically engineered GT-tg mouse may be useful for improving our understanding of the neurological underpinnings of neuroAIDS-related behaviors.
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Affiliation(s)
- Amanda N Carey
- Northeastern University, Department of Psychology, 360 Huntington Ave., Boston, MA 02115, USA
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17
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Grovit-Ferbas K, Harris-White ME. Thinking about HIV: the intersection of virus, neuroinflammation and cognitive dysfunction. Immunol Res 2010; 48:40-58. [DOI: 10.1007/s12026-010-8166-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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18
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Cho S, Wood A, Bowlby MR. Brain slices as models for neurodegenerative disease and screening platforms to identify novel therapeutics. Curr Neuropharmacol 2010; 5:19-33. [PMID: 18615151 DOI: 10.2174/157015907780077105] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 12/07/2006] [Accepted: 01/01/2007] [Indexed: 11/22/2022] Open
Abstract
Recent improvements in brain slice technology have made this biological preparation increasingly useful for examining pathophysiology of brain diseases in a tissue context. Brain slices maintain many aspects of in vivo biology, including functional local synaptic circuitry with preserved brain architecture, while allowing good experimental access and precise control of the extracellular environment, making them ideal platforms for dissection of molecular pathways underlying neuronal dysfunction. Importantly, these ex vivo systems permit direct treatment with pharmacological agents modulating these responses and thus provide surrogate therapeutic screening systems without recourse to whole animal studies. Virus or particle mediated transgenic expression can also be accomplished relatively easily to study the function of novel genes in a normal or injured brain tissue context.In this review we will discuss acute brain injury models in organotypic hippocampal and co-culture systems and the effects of pharmacological modulation on neurodegeneration. The review will also cover the evidence of developmental plasticity in these ex vivo models, demonstrating emergence of injury-stimulated neuronal progenitor cells, and neurite sprouting and axonal regeneration following pathway lesioning. Neuro-and axo-genesis are emerging as significant factors contributing to brain repair following many acute and chronic neurodegenerative disorders. Therefore brain slice models may provide a critical contextual experimental system to explore regenerative mechanisms in vitro.
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Affiliation(s)
- Seongeun Cho
- Discovery Neuroscience, Wyeth Research, CN8000, Princeton, NJ 08543, USA.
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19
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Aksenov MY, Aksenova MV, Mactutus CF, Booze RM. HIV-1 protein-mediated amyloidogenesis in rat hippocampal cell cultures. Neurosci Lett 2010; 475:174-8. [PMID: 20363291 DOI: 10.1016/j.neulet.2010.03.073] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 03/24/2010] [Accepted: 03/26/2010] [Indexed: 10/25/2022]
Abstract
Since the beginning of the highly active antiretroviral therapy (HAART) era, epidemiological evidence indicates an increasing incidence of Alzheimer's (AD)-like brain pathology in aging HIV patients. Emerging evidence warns of potential convergent mechanisms underlying HIV- and Abeta-mediated neurodegeneration. We found that HIV-1 Tat B and gp120 promote the secretion of Abeta 1-42 in primary rat fetal hippocampal cell cultures. Our results demonstrate that the variant of Tat expressed by the neurotropic subtype of HIV-1 virus (HIV-1 clade B) specifically induces both the release of amyloidogenic Abeta 1-42 and the accumulation of cell-bound amyloid aggregates. The results of the research rationalize testing of the ability of beta-amyloid aggregation inhibitors to attenuate HIV protein-mediated cognitive deficits in animal models of NeuroAIDS. The long-term goal of the study is to evaluate the potential benefits of anti-amyloidogenic therapies for management of cognitive dysfunction in aging HIV-1 patients.
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Affiliation(s)
- M Y Aksenov
- Program in Behavioral Neuroscience, University of South Carolina, United States.
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20
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Self RL, Smith KJ, Butler TR, Pauly JR, Prendergast MA. Intra-cornu ammonis 1 administration of the human immunodeficiency virus-1 protein trans-activator of transcription exacerbates the ethanol withdrawal syndrome in rodents and activates N-methyl-D-aspartate glutamate receptors to produce persisting spatial learning deficits. Neuroscience 2009; 163:868-76. [PMID: 19619615 PMCID: PMC2773563 DOI: 10.1016/j.neuroscience.2009.07.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 07/11/2009] [Accepted: 07/14/2009] [Indexed: 11/22/2022]
Abstract
Human immunodeficiency virus-1 (HIV-1) infection may produce neurological deficits, such as cognitive decline, that may be worsened by concurrent ethanol (EtOH) abuse. Among the many biochemical cascades likely mediating HIV-1-associated neuronal injury is enhancement of N-methyl-d-aspartate (NMDA) receptor function and progression to excitotoxicity, an effect that may be directly or indirectly related to accumulation in brain of the HIV-1 trans-activator of transcription (Tat) factor. The present studies were designed to examine the hypothesis that binge-like EtOH pre-exposure would enhance effects of Tat on NMDA receptor function. These studies employed a modified in vivo binge EtOH exposure regimen designed to produce peak blood EtOH levels (BEL) of <200 mg/dl in adult male rats and were designed to examine effects of intra-hippocampal injection of Tat (0.5 microl/500 pM/2 min) on EtOH withdrawal-related behavior, spatial learning, and histological measures. Unilateral cannulae were implanted into the cornu ammonis 1 (CA1) pyramidal cell layer of animals prior to beginning a 4-day binge EtOH regimen. EtOH was administered via intragastric intubation ( approximately 3.0-5.0 g/kg) with dose determined by behavioral ratings of intoxication daily for 4 days (at 08:00, 16:00, and 24:00 h). EtOH withdrawal behaviors were monitored 12 h after the last administration of EtOH. Morris water maze learning was assessed during the following 4 days, at which times brains were harvested for autoradiographic measurement of NMDA receptor density and neuroinflammation. Maximal BELs of 187.69 mg/dl were observed 60 min after EtOH administration on day 2 of the regimen. In contrast, peak BELs of approximately 100 mg/dl were observed 60 min after EtOH administration on day 4 of the regimen, suggesting development of metabolic tolerance. Significant behavioral abnormalities were observed in EtOH withdrawn animals, including tremor and seizures. Intra-CA1 region injection of Tat significantly potentiated EtOH withdrawal behavioral abnormalities, an effect that was reduced by MK-801 pre-exposure. While EtOH withdrawn animals showed learning similar to control animals, EtOH withdrawn animals that received intra-CA1 Tat injection demonstrated persisting deficits in spatial learning on days 3 and 4 of training, effects that were markedly reduced by administration of the competitive NMDA receptor antagonist MK-801 30 min prior to Tat injection. No changes in [(3)H]MK-801 binding were observed. Binding density of [(3)H]PK11195, a ligand for peripheral benzodiazepine receptors expressed on activated microglia, was elevated proximal to cannula tracks in all animals, but was not altered by EtOH or Tat exposure. These findings suggest that EtOH abuse and/or dependence in HIV-positive individuals may promote HIV-1-associated cognitive deficits by altering NMDA receptor function in the absence of microglial activation or neuroinflammation.
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Affiliation(s)
- Rachel L. Self
- University of Kentucky, Department of Psychology, 741 South Limestone St., Lexington, KY 40536-0509
- University of Kentucky, Spinal Cord and Brain Injury Research Center, 741 South Limestone St., Lexington, KY 40536-0509
| | - Katherine J. Smith
- University of Kentucky, Department of Psychology, 741 South Limestone St., Lexington, KY 40536-0509
- University of Kentucky, Spinal Cord and Brain Injury Research Center, 741 South Limestone St., Lexington, KY 40536-0509
| | - Tracy R. Butler
- University of Kentucky, Department of Psychology, 741 South Limestone St., Lexington, KY 40536-0509
- University of Kentucky, Spinal Cord and Brain Injury Research Center, 741 South Limestone St., Lexington, KY 40536-0509
| | - James R. Pauly
- University of Kentucky, Department of Pharmaceutical Sciences, 741 South Limestone St., Lexington, KY 40536-0509
- University of Kentucky, Spinal Cord and Brain Injury Research Center, 741 South Limestone St., Lexington, KY 40536-0509
| | - Mark A. Prendergast
- University of Kentucky, Department of Psychology, 741 South Limestone St., Lexington, KY 40536-0509
- University of Kentucky, Spinal Cord and Brain Injury Research Center, 741 South Limestone St., Lexington, KY 40536-0509
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21
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Neuropsychological assessment of HIV-infected populations in international settings. Neuropsychol Rev 2009; 19:232-49. [PMID: 19455425 PMCID: PMC2690834 DOI: 10.1007/s11065-009-9096-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Accepted: 04/30/2009] [Indexed: 12/03/2022]
Abstract
Resource-limited regions of the world represent the areas most affected by the global HIV epidemic. Currently, there are insufficient data on the neurocognitive effects of HIV in these areas and neuropsychological studies that have been carried out thus far are marked by inconsistent methods, test batteries, and rating systems for levels of cognitive impairment. These differences in methods, along with genetic variability of both virus and host, differences in co-infections and other co-morbidities, differences in language and culture, and infrastructural deficiencies in many international settings create challenges to the assessment of neurocognitive functioning and interpretation of neuropsychological data. Identifying neurocognitive impairment directly attributable to HIV, exploring relationships between HIV-associated neurocognitive impairment, disease variables, and everyday functioning, evaluating differences in HIV-1 subtype associated neuropathology, and determining implications for treatment remain complicated and challenging goals. Endeavors to establish a more standardized approach to neurocognitive assessments across international studies in addition to accumulating appropriate normative data that will allow more accurate rating of neuropsychological test performance will be crucial to future efforts attempting to achieve these goals.
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Neonatal intrahippocampal injection of the HIV-1 proteins gp120 and Tat: differential effects on behavior and the relationship to stereological hippocampal measures. Brain Res 2008; 1232:139-54. [PMID: 18674522 DOI: 10.1016/j.brainres.2008.07.032] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 04/29/2008] [Accepted: 07/09/2008] [Indexed: 11/21/2022]
Abstract
HIV-1 proteins, such as Tat and gp120, are believed to play a crucial role in the central nervous system (CNS) pathology of acquired immune deficiency syndrome (AIDS). The present study sought to determine the potential role of Tat and/or gp120 on behavioral development and the relationship to the long-term effects of the HIV-1 proteins on the rat hippocampus. Male pups of 13 Sprague-Dawley litters were bilaterally injected on postnatal day (P)1. Every litter contributed an animal to each of four treatment condition: VEH (0.5 microl sterile buffer), gp120 (100 ng), Tat (25 microg) or combined gp120+Tat (100 ng+25 microg). Body weight was not affected by either protein treatment. Tat revealed a transient effect on many of the behavioral assessments early in development as well as on preattentive processes and spatial memory in adulthood. Gp120 had more selective effects on negative geotaxis (P8-P10) and on locomotor activity (P94-P96). Combined gp120+Tat effects were noted for eye opening with potential interactive effects of gp120 and Tat on negative geotaxis. Anatomical assessment at approximately 7 1/2 months of age was conducted by using design-based stereology to quantify the total cell number in five hippocampal subregions [granule layer (GL), hilus of the dentate gyrus (DGH), cornu ammonis fields (CA)2/3, CA1, and subiculum (SUB)] [Fitting, S., Booze, R.M., Hasselrot, U., Mactutus, C.F., 2007a. Differential long-term neurotoxicity of HIV-1 proteins in the rat hippocampal formation: a design-based stereological study. Hippocampus 18(2), 135-147]. A relationship between early reflex development and estimated cell number in the adult hippocampus was indicated by simple regression analyses. In addition, estimated number of neurons and astrocytes in the DGH explained 81% of the variance of the distribution of searching behavior in the probe test. Collectively, these data indicate that the DGH may participate in the spatial memory alterations observed in adulthood consequent to neonatal exposure to HIV-1 proteins.
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Blanco A, Alvarez S, Fresno M, Muñoz-Fernández MA. Extracellular HIV-Tat induces cyclooxygenase-2 in glial cells through activation of nuclear factor of activated T cells. THE JOURNAL OF IMMUNOLOGY 2008; 180:530-40. [PMID: 18097055 DOI: 10.4049/jimmunol.180.1.530] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Both the HIV-1 protein Tat and cyclooxygenase-2 (COX-2) have been involved in the neuropathogenesis associated with HIV-1 infection. However, the relationship among them has not been addressed. Here, we found that extracellular Tat was able to induce COX-2 mRNA and protein expression and PGE2 synthesis in astrocytoma cell lines and primary human astrocytes. Moreover, Tat induced COX-2 promoter transcription. Deletion of NF-kappaB sites of the promoter did not diminish Tat-dependent transcription. Interestingly, Tat did not induce NF-kappaB activity, suggesting that NF-kappaB was not necessary to control COX-2 transcription induced by Tat. In contrast, deletion or mutation of the NFAT and/or AP-1 site abrogated COX-2 induction by Tat. Moreover, Tat induced transcription of NFAT- and AP-1-dependent reporter genes. Transfection of a dominant negative c-Jun mutant protein, TAM-67, or of a dominant negative version of NFAT, efficiently blocked the induction of COX-2 promoter by Tat, confirming the requirement of both transcription factors. Moreover, Tat induced NFAT translocation to the nucleus and binding to the distal site of the COX-2 promoter. The importance of NFAT and AP-1 in COX-2 induction and PGE2 synthesis by Tat was corroborated by using pharmacological inhibitors of the NFAlphaTau, ERK, and JNK pathways. In summary, our results indicate that HIV-1 Tat was able to induce COX-2 and PGE2 synthesis in astrocytic cells through an NFAT/AP-1-dependent mechanism.
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Affiliation(s)
- Almudena Blanco
- Laboratorio Inmuno-Biología Molecular, Hospital General Universitario Gregorio Marañón, Madrid, Spain
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Fitting S, Booze RM, Hasselrot U, Mactutus CF. Differential long-term neurotoxicity of HIV-1 proteins in the rat hippocampal formation: a design-based stereological study. Hippocampus 2008; 18:135-47. [PMID: 17924522 DOI: 10.1002/hipo.20376] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The human immunodeficiency virus type 1 (HIV-1) proteins, gp120 and Tat, are believed to play a role in mediating central nervous system (CNS) pathology in HIV-1 infected patients. Using design-based stereology, we examined the role of neonatal intrahippocampal injections of gp120 and Tat on the adult hippocampus ( approximately 7(1/2) month). Postnatal day (P)1-treated Sprague-Dawley rats were bilaterally injected with vehicle (VEH, 0.5 microl sterile buffer), gp120 (100 ng), Tat (25 microg) or combined gp120 + Tat (100 ng + 25 microg). Using Nissl-stained tissue sections, we quantified total neurons in five subregions of the rat hippocampus [granual layer (GL), hilus of the dentate gyrus (DGH), cornu ammonis fields (CA)2/3, CA1, and subiculum (SUB)], and total glial cells (astrocytes and oligodendrocytes) in two subregions (DGH and SUB). Estimates of cell area and cell volume were taken in the DGH. There was a significant reduction of neuron number in the CA2/3 subfield by Tat and gp120, and a significant reduction in the DGH by Tat only. For glial cells, numbers of astrocytes in the DGH and SUB were increased by the Tat protein, whereas no effects were noted for gp120. Finally, for oligodendrocytes Tat increased cell number in the DGH but not in any other region; gp120 had no detectable effect in any brain region. Estimates of cell area and cell volume of the three different cell types revealed no significant differences between treatments. Collectively, these results suggest differential effects of gp120 and Tat on the estimated total number of neurons, as well as on the number of glial cells.
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Affiliation(s)
- Sylvia Fitting
- Department of Psychology, University of South Carolina, Columbia, South Carolina SC 29208, USA.
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Brailoiu GC, Brailoiu E, Chang JK, Dun NJ. Excitatory effects of human immunodeficiency virus 1 Tat on cultured rat cerebral cortical neurons. Neuroscience 2007; 151:701-10. [PMID: 18164555 DOI: 10.1016/j.neuroscience.2007.11.031] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Revised: 11/20/2007] [Accepted: 11/29/2007] [Indexed: 01/26/2023]
Abstract
Human immunodeficiency virus 1 (HIV-1) Tat protein is one of the neurotoxins involved in the pathogenesis of HIV-1-associated neuronal disorders. Combined electrophysiological and optical imaging experiments were undertaken to investigate whether HIV-1 Tat30-86, herein referred to as Tat30-86, acted directly or indirectly via the release of glutamate or both and to test its effect on the properties of spontaneous quantal events in cultured cortical neurons. Whole-cell patch recordings were made from cultured rat cortical neurons in either current- or voltage-clamp mode. Tat30-86 (50-1000 nM) induced in a population of cortical neurons a long-lasting depolarization, which was accompanied by a decrease of membrane resistance and persisted in a Krebs solution containing tetrodotoxin (TTX, 0.5 microM). Depolarizations were slightly reduced by pretreatment with glutamate receptor antagonists 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) (10 microM) and d-2-amino-5-phosphonovaleric acid (AP-5) (50 microM), and were markedly reduced in a Ca(2+)-free Krebs solution; the differences were statistically significant. Tat30-86-induced inward currents had a reversal potential between -30 and 0 mV. While not causing a noticeable depolarization, lower concentrations of Tat30-86 (10 nM) increased membrane excitability, as indicated by increased numbers of neuronal discharge in response to a step depolarizing pulse. Tat30-86 (10 nM) increased the frequency of spontaneous miniature excitatory postsynaptic currents (mEPSCs), while not significantly affecting their amplitude. Tat30-86 (10 nM) moderately increased the frequency as well as the amplitude of spontaneous miniature inhibitory postsynaptic currents (mIPSCs). Ratiometric Ca(2+) imaging studies showed that Tat30-86 produced three types of Ca(2+) responses: 1) a fast and transitory increase, 2) Ca(2+) oscillations, and 3) a fast increase followed by a plateau; the glutamate receptor antagonists eliminated the late component of Ca(2+) response. The result suggests that Tat30-86 is an active fragment and that it excites cortical neurons directly and indirectly via releasing glutamate from adjacent neurons.
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Affiliation(s)
- G C Brailoiu
- Department of Pharmacology, Temple University School of Medicine, 3420 North Broad Street, Philadelphia, PA 19140, USA.
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Liner KJ, Hall CD, Robertson KR. Impact of human immunodeficiency virus (HIV) subtypes on HIV-associated neurological disease. J Neurovirol 2007; 13:291-304. [PMID: 17849313 DOI: 10.1080/13550280701422383] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Among the many variables affecting transmission and pathogenesis of the human immunodeficiency virus type 1(HIV-1), the effects of HIV subtypes, or clades, on disease progression remain unclear. Although debated, some studies have found that the variable env and pol sequences of different subtypes of HIV-1 may endow some subtypes with greater degrees of cell tropism, virulence, and drug resistance, which may lead to differences in overall disease progression. HIV-associated dementia (HAD) appears to be associated with viral diversity and markers of immune activation. Africa has the highest prevalence of HIV, largest viral diversity, and is where clade recombination occurs most frequently. All of these factors would suggest that HAD would pose the largest threat in this region of the world. Although investigations into the effects of different subtypes on overall disease progression are well documented, few have looked into the effects of subtypes on neurological disease progression. This review highlights the need for more international research involving the neurological effects and especially the clinical presentation of dementia for the entire range of the group M HIV-1 subtypes.
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Affiliation(s)
- Kevin J Liner
- Department of Neurology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Spatial learning and memory in HIV-1 transgenic rats. J Neuroimmune Pharmacol 2007; 2:319-28. [PMID: 18040850 DOI: 10.1007/s11481-007-9078-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Accepted: 05/29/2007] [Indexed: 10/23/2022]
Abstract
HIV-1 infection of the central nervous system impairs neural, cognitive, and behavioral functioning in patients despite antiretroviral therapy. However, studying mechanisms underlying HIV-1-related neurological and cognitive dysfunction has been limited without an adequate animal model. A novel, noninfectious HIV-1 transgenic (HIV-1Tg) rat model was recently created that expresses an HIV-1 provirus with a deletion of functional gag and pol genes. This HIV-1Tg rat reportedly develops clinical manifestations of human HIV disease and thus appears to mimic the persistent infection that results from the presence of HIV viral proteins in the host. We evaluated the HIV-1Tg rat model using the Morris water maze, a popular paradigm for testing learning and memory deficits in rodents. Because of congenital cataracts in HIV-1Tg rats, however, the traditional use of visual navigational cues in this paradigm were precluded. We first designed a modified Morris water maze and demonstrated that neurologically intact rats can effectively learn the water maze in the absence of visual cues and in the presence of non-visual navigation cues. We then tested HIV-1Tg rats in this modified Morris water maze. These HIV-1Tg rats showed a deficit in learning how to swim to the location of the hidden platform but did not show a deficit in their memory of the general location of the hidden platform. These results suggest that the noninfectious HIV-1Tg rat can be a valid model for the behavioral studies of HIV-related neurological dysfunction.
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Fitting S, Booze RM, Hasselrot U, Mactutus CF. Intrahippocampal injections of Tat: Effects on prepulse inhibition of the auditory startle response in adult male rats. Pharmacol Biochem Behav 2006; 84:189-96. [PMID: 16790267 DOI: 10.1016/j.pbb.2006.04.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2005] [Revised: 03/27/2006] [Accepted: 04/11/2006] [Indexed: 12/26/2022]
Abstract
The presence of human immunodeficiency virus (HIV-1) in the brain mediates the pathogenesis of HIV-associated dementia complex (HAD), partially through the viral toxins gp120 and Tat. This study characterized potential deficits in sensorimotor gating, as measured by prepulse inhibition (PPI), following hippocampal administration of Tat. Adult, male Sprague-Dawley rats were bilaterally injected with 50 microg Tat or saline (1 microl volume), into the hippocampus. Following 7 weeks of recovery, all animals were tested using the auditory startle response (ASR) with habituation, control, and PPI trials. Assessment of ASR habituation [100dB(A) white noise stimulus, 70dB(A) background, 5-min acclimation period, 36 habituation trials with fixed interstimulus interval (ISI) of 10 s] demonstrated a significant approximately 50% reduction in the overall peak ASR amplitude, but no change in peak ASR latency, nor an effect on the rate of habituation. PPI measures demonstrated robust alterations in sensorimotor gating. The PPI test (ISI of 0, 8, 40, 80, 120, or 4000 ms, 6-trial blocks, Latin-square) showed an attenuated response on peak ASR amplitude during the control trials (0 and 4000 ms ISI), but not on the PPI trials (8-120 ms ISI). Most striking was the rightward shift in ISI for maximal inhibition of the response (chi2(1)=4.7, p<or=0.03). There was no significant peak ASR latency effect during the control trials (<1 ms) of the PPI test, although there was the suggestion of a slowing of the response (4 ms, approximately 15%) across PPI trials. Collectively, the present data suggest that intrahippocampal injections of Tat have adverse effects on cognitive processing, as indexed by sensorimotor gating.
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Affiliation(s)
- Sylvia Fitting
- Department of Psychology, University of South Carolina, 1512 Pendleton Street, Columbia, South Carolina 29208, USA.
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Fitting S, Booze RM, Mactutus CF. Neonatal hippocampal Tat injections: developmental effects on prepulse inhibition (PPI) of the auditory startle response. Int J Dev Neurosci 2006; 24:275-83. [PMID: 16530999 PMCID: PMC4042027 DOI: 10.1016/j.ijdevneu.2006.02.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Revised: 02/02/2006] [Accepted: 02/02/2006] [Indexed: 01/22/2023] Open
Abstract
The current estimate of children (<15 years) living with HIV and AIDS is 2.2 million. The major source of infection occurs through vertical transmission of the virus from mother to child during delivery [UNAIDS/WHO, 2005. AIDS Epidemic Update. UNAIDS, Geneva]. Recent studies have shown that timing of HIV-1 infection might be related to the onset and rate of progression of CNS disease. The effects of HIV on the brain are thought to be mediated indirectly through the viral toxins Tat and gp120. This study characterized developmental effects on PPI following intrahippocampal administration of Tat. On postnatal day (P)1, one male and one female pup from each of eight Sprague-Dawley litters were bilaterally injected with 50 microg Tat or saline (1 microl volume). Animals were tested for PPI of the auditory startle response (ASR) (ISIs of 0, 8, 40, 80, 120, and 4000 ms, six trial blocks, Latin-square design) on days 30, 60 and 90. Tat altered PPI and the pattern of alterations was different for males and females. For males, a leftward shift was evident in the ISI for maximal inhibition of the response on day 30 and on day 60 (chi(2)(1)=4.7, p< or =.03, and chi(2)(1)=5.3, p< or =.02, respectively), but not on day 90. For females, Tat altered peak ASR latency across PPI trials (8-120 ms) at all days of testing (30, 60, and 90 days of age), as indexed by orthogonal component analyses, indicating less modulation of PPI by ISI. Data collected from a second group that were tested only once at 90 days of age, suggested that the observed adverse Tat effects for males and females early in development were maintained with age. Thus, the diminishing TAT effect on PPI at day 90 in a longitudinal study design was attributed to repeated testing, rather than 'recovery of function'. Collectively, the data suggested that hippocampal Tat injections in neonatal rats produced alterations in the pre-attentive process of sensorimotor gating, as indexed by PPI.
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Affiliation(s)
- Sylvia Fitting
- Corresponding author at: Department of Psychology, University of South Carolina, 1512 Pendleton Street, Columbia, SC 29208, USA., Tel.: +1 803 348 7179; fax: +1 803 777 9558
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Longordo F, Feligioni M, Chiaramonte G, Sbaffi PF, Raiteri M, Pittaluga A. The human immunodeficiency virus-1 protein transactivator of transcription up-regulates N-methyl-D-aspartate receptor function by acting at metabotropic glutamate receptor 1 receptors coexisting on human and rat brain noradrenergic neurones. J Pharmacol Exp Ther 2006; 317:1097-105. [PMID: 16489129 DOI: 10.1124/jpet.105.099630] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the effects of the human immunodeficiency virus-1 transactivator of transcription (Tat) on the release of norepinephrine (NE) from human and rat brain synaptosomes. Tat could not evoke directly release of [3H]NE. In the presence of Tat (1 nM), N-methyl-D-aspartate (NMDA) concentrations unable to release (human synaptosomes) or slightly releasing (rat synaptosomes) [3H]NE became very effective. The NMDA/Tat-evoked release depends on NMDA receptors (NMDARs) since it was abolished by MK-801 (dizocilpine). Tat binding at NMDARs was excluded. The NMDA-induced release of [3H]NE in the presence of glycine was further potentiated by Tat. The release evoked by NMDA/glycine/Tat depends on metabotropic glutamate receptor 1 (mGluR1) activation, since it was halved by mGluR1 antagonists. Tat seems to act at the glutamate recognition site of mGluR1. Recently, Tat was shown to release [3H]acetylcholine from human cholinergic terminals; here, we demonstrate that this effect is also mediated by presynaptic mGluR1. The peptide sequence Tat41-60, but not Tat61-80, mimicked Tat. Phospholipase C, protein kinase C, and cytosolic tyrosine kinase are involved in the NMDA/glycine/Tat-evoked [3H]NE release. To conclude, Tat can represent a potent pathological agonist at mGlu1 receptors able to release acetylcholine from human cholinergic terminals and up-regulate NMDARs mediating NE release from human and rat noradrenergic terminals.
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Affiliation(s)
- Fabio Longordo
- Pharmacology and Toxicology Section, Department of Experimental Medicine, University of Genova, Genova, Italy
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Rose H, Woolley I, Hoy J, Dart A, Bryant B, Mijch A, Sviridov D. HIV infection and high-density lipoprotein: the effect of the disease vs the effect of treatment. Metabolism 2006; 55:90-5. [PMID: 16324925 DOI: 10.1016/j.metabol.2005.07.012] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2005] [Accepted: 07/11/2005] [Indexed: 12/13/2022]
Abstract
HIV infection is commonly associated with hypoalphalipoproteinemia. It is not clear how much the HIV infection and/or treatment contribute to the changes in high-density lipoprotein (HDL) levels. Blood lipids of HIV-positive males were assessed in a retrospective study. The following groups of patients were studied: (1) untreated for at least 6 months; (2) treatment with highly active antiretroviral therapy (HAART) without protease inhibitor (PI); (3) treatment with a HAART regimen that includes a PI (HAART/PI); (4) treatment with HAART that includes low-dose ritonavir and a PI (HAART/PI/boost). Lipoprotein levels were compared with those of age-matched HIV-negative healthy subjects. Compared with the control group, HDL-cholesterol (HDL-C) levels were 22%, 11%, 14%, and 11% lower for currently untreated HIV, HAART, HAART/PI, and HAART/PI/boost groups, respectively. Negative correlations were found among HDL-C level, peak and current viral load, and duration of the disease and the treatment. A positive correlation was found between HDL-C and current and nadir CD4 cell count and CD4 percentage. When patients were divided into subgroups based on duration of antiretroviral therapy, patients treated with HAART and HAART/PI for 3 to 6 years were significantly less likely to have high HDL-C levels compared with the control group and patients treated for 1 to 3 years. A 5-fold decrease in the proportion of subjects with high HDL-C and a 3-fold increase in those with low HDL-C were found in the group treated with HAART/PI/boost. These data suggest that hypoalphalipoproteinemia in patients with HIV is likely to be secondary to HIV infection itself.
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Affiliation(s)
- Honor Rose
- Baker Heart Research Institute, Melbourne 3004, Australia.
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Kramer-Hämmerle S, Rothenaigner I, Wolff H, Bell JE, Brack-Werner R. Cells of the central nervous system as targets and reservoirs of the human immunodeficiency virus. Virus Res 2005; 111:194-213. [PMID: 15885841 DOI: 10.1016/j.virusres.2005.04.009] [Citation(s) in RCA: 234] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The availability of highly active antiretroviral therapies (HAART) has not eliminated HIV-1 infection of the central nervous system (CNS) or the occurrence of HIV-associated neurological problems. Thus, the neurobiology of HIV-1 is still an important issue. Here, we review key features of HIV-1-cell interactions in the CNS and their contributions to persistence and pathogenicity of HIV-1 in the CNS. HIV-1 invades the brain very soon after systemic infection. Various mechanisms have been proposed for HIV-1 entry into the CNS. The most favored hypothesis is the migration of infected cells across the blood-brain barrier ("Trojan horse" hypothesis). Virus production in the CNS is not apparent before the onset of AIDS, indicating that HIV-1 replication in the CNS is successfully controlled in pre-AIDS. Brain macrophages and microglia cells are the chief producers of HIV-1 in brains of individuals with AIDS. HIV-1 enters these cells by the CD4 receptor and mainly the CCR5 coreceptor. Various in vivo and cell culture studies indicate that cells of neuroectodermal origin, particularly astrocytes, may also be infected by HIV-1. These cells restrict virus production and serve as reservoirs for HIV-1. A limited number of studies suggest restricted infection of oligodendrocytes and neurons, although infection of these cells is still controversial. Entry of HIV-1 into neuroectodermal cells is independent of the CD4 receptor, and a number of different cell-surface molecules have been implicated as alternate receptors of HIV-1. HIV-1-associated injury of the CNS is believed to be caused by numerous soluble factors released by glial cells as a consequence of HIV-1 infection. These include both viral and cellular factors. Some of these factors can directly induce neuronal injury and death by interacting with receptors on neuronal membranes (neurotoxic factors). Others can activate uninfected cells to produce inflammatory and neurotoxic factors and/or promote infiltration of monocytes and T-lymphocytes, thus amplifying the deleterious effects of HIV-1 infection. CNS responses to HIV-1 infection also include mechanisms that enhance neuronal survival and strengthen crucial neuronal support functions. Future challenges will be to develop strategies to prevent HIV-1 spread in the brain, bolster intrinsic defense mechanisms of the brain and to elucidate the impact of long-term persistence of HIV-1 on CNS functions in individuals without AIDS.
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Affiliation(s)
- Susanne Kramer-Hämmerle
- Institute of Molecular Virology, GSF-National Research Center for Environment and Health, Ingolstädter Landstrasse 1, D-85764 Neuherberg, Germany
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