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Davis SE, Cirincione AB, Jimenez-Torres AC, Zhu J. The Impact of Neurotransmitters on the Neurobiology of Neurodegenerative Diseases. Int J Mol Sci 2023; 24:15340. [PMID: 37895020 PMCID: PMC10607327 DOI: 10.3390/ijms242015340] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/16/2023] [Accepted: 10/17/2023] [Indexed: 10/29/2023] Open
Abstract
Neurodegenerative diseases affect millions of people worldwide. Neurodegenerative diseases result from progressive damage to nerve cells in the brain or peripheral nervous system connections that are essential for cognition, coordination, strength, sensation, and mobility. Dysfunction of these brain and nerve functions is associated with Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis, and motor neuron disease. In addition to these, 50% of people living with HIV develop a spectrum of cognitive, motor, and/or mood problems collectively referred to as HIV-Associated Neurocognitive Disorders (HAND) despite the widespread use of a combination of antiretroviral therapies. Neuroinflammation and neurotransmitter systems have a pathological correlation and play a critical role in developing neurodegenerative diseases. Each of these diseases has a unique pattern of dysregulation of the neurotransmitter system, which has been attributed to different forms of cell-specific neuronal loss. In this review, we will focus on a discussion of the regulation of dopaminergic and cholinergic systems, which are more commonly disturbed in neurodegenerative disorders. Additionally, we will provide evidence for the hypothesis that disturbances in neurotransmission contribute to the neuronal loss observed in neurodegenerative disorders. Further, we will highlight the critical role of dopamine as a mediator of neuronal injury and loss in the context of NeuroHIV. This review will highlight the need to further investigate neurotransmission systems for their role in the etiology of neurodegenerative disorders.
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Affiliation(s)
| | | | | | - Jun Zhu
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, 715 Sumter Street, Columbia, SC 29208, USA; (S.E.D.); (A.B.C.); (A.C.J.-T.)
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2
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Ajasin D, Eugenin EA. HIV-1 Tat: Role in Bystander Toxicity. Front Cell Infect Microbiol 2020; 10:61. [PMID: 32158701 PMCID: PMC7052126 DOI: 10.3389/fcimb.2020.00061] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 02/06/2020] [Indexed: 12/21/2022] Open
Abstract
HIV Tat protein is a critical protein that plays multiple roles in HIV pathogenesis. While its role as the transactivator of HIV transcription is well-established, other non-viral replication-associated functions have been described in several HIV-comorbidities even in the current antiretroviral therapy (ART) era. HIV Tat protein is produced and released into the extracellular space from cells with active HIV replication or from latently HIV-infected cells into neighboring uninfected cells even in the absence of active HIV replication and viral production due to effective ART. Neighboring uninfected and HIV-infected cells can take up the released Tat resulting in the upregulation of inflammatory genes and activation of pathways that leads to cytotoxicity observed in several comorbidities such as HIV associated neurocognitive disorder (HAND), HIV associated cardiovascular impairment, and accelerated aging. Thus, understanding how Tat modulates host and viral response is important in designing novel therapeutic approaches to target the chronic inflammatory effects of soluble viral proteins in HIV infection.
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Affiliation(s)
- David Ajasin
- Department of Neuroscience, Cell Biology, and Anatomy, University of Texas Medical Branch, Galveston, TX, United States
| | - Eliseo A Eugenin
- Department of Neuroscience, Cell Biology, and Anatomy, University of Texas Medical Branch, Galveston, TX, United States
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3
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Vergassola M, Olivero G, Cisani F, Usai C, Bossi S, Puliti A, Pittaluga A. Presynaptic mGlu1 Receptors Control GABA B Receptors in an Antagonist-Like Manner in Mouse Cortical GABAergic and Glutamatergic Nerve Endings. Front Mol Neurosci 2018; 11:324. [PMID: 30279647 PMCID: PMC6153310 DOI: 10.3389/fnmol.2018.00324] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 08/22/2018] [Indexed: 01/03/2023] Open
Abstract
Mouse cortical GABAergic synaptosomes possess presynaptic inhibitory GABAB autoreceptors. Accordingly, (±)baclofen (3 μM) inhibits in a CGP53423-sensitive manner the 12 mM KCl-evoked release of preloaded [3H]GABA. Differently, the existence of presynaptic release-regulating metabotropic glutamate type 1 (mGlu1) heteroreceptors in these terminals is still matter of discussion, although confocal microscopy unveiled the existence of mGlu1α with GABAB1 or GABAB2 proteins in cortical VGAT-positive synaptosomes. The group I mGlu agonist 3,5-DHPG failed to modify on its own the 12 mM KCl-evoked [3H]GABA exocytosis from cortical nerve endings, but, when added concomitantly to the GABAB agonist, it significantly reduced the 3 μM (±)baclofen-induced inhibition of [3H]GABA exocytosis. Conversely, the mGlu1 antagonist LY367385 (0.03–1 μM), inactive on its own on GABA exocytosis, amplified the 3 μM (±)baclofen-induced inhibition of [3H]GABA overflow. The ( ± )baclofen-induced inhibition of [3H]GABA exocytosis was more pronounced in cortical synaptosomes from Grm1crv4/crv4 mice, which bear a spontaneous mutation of the Grm1 gene leading to the functional inactivation of the mGlu1 receptor. Inasmuch, the expression of GABAB2 receptor protein in cortical synaptosomal lysates from Grm1crv4/crv4 mice was increased when compared to controls. Altogether, these observations seem best interpreted by assuming that mGlu1 coexist with GABAB receptors in GABAergic cortical synaptosomes, where they control GABA receptors in an antagonist-like manner. We then asked whether the mGlu1-mediated control of GABAB receptors is restricted to GABAergic terminals, or if it occurs also in other subpopulations of nerve endings. Release-regulating GABAB receptors also exist in glutamatergic nerve endings. (±)baclofen (1 μM) diminished the 12 mM KCl-evoked [3H]D-aspartate overflow. Also in these terminals, the concomitant presence of 1 μM LY367385, inactive on its own, significantly amplified the inhibitory effect exerted by (±)baclofen on [3H]D-aspartate exocytosis. Confocal microscopy confirmed the colocalization of mGlu1 with GABAB1 and GABAB2 labeling in vesicular glutamate type1 transporter-positive particles. Our results support the conclusion that mGlu1 receptors modulate in an antagonist-like manner presynaptic release-regulating GABAB receptors. This receptor–receptor interaction could be neuroprotective in central disease typified by hyperglutamatergicity.
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Affiliation(s)
| | | | | | - Cesare Usai
- Institute of Biophysics, National Research Council, Genoa, Italy
| | - Simone Bossi
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Aldamaria Puliti
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.,IRCCS Istituto Giannina Gaslini, Genoa, Italy.,Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| | - Anna Pittaluga
- Department of Pharmacy, University of Genoa, Genoa, Italy.,Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
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4
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Rubin LH, Radtke KK, Eum S, Tamraz B, Kumanan KN, Springer G, Maki PM, Anastos K, Merenstein D, Karim R, Weber KM, Gustafson D, Greenblatt RM, Bishop JR. Cognitive Burden of Common Non-antiretroviral Medications in HIV-Infected Women. J Acquir Immune Defic Syndr 2018; 79:83-91. [PMID: 29781879 PMCID: PMC6092212 DOI: 10.1097/qai.0000000000001755] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
OBJECTIVE The aging HIV population has increased comorbidity burden and consequently non-antiretroviral medication utilization. Many non-antiretroviral medications have known neurocognitive-adverse effects ("NC-AE medications"). We assessed the cognitive effects of NC-AE medications in HIV+ and HIV- women. METHODS One thousand five hundred fifty-eight participants (1037 HIV+; mean age 46) from the Women's Interagency HIV Study completed a neuropsychological test battery between 2009 and 2011. The total number of NC-AE medications and subgroups (eg, anticholinergics) were calculated based on self-report. Generalized linear models for non-normal data were used to examine the cognitive burden of medications and factors that exacerbate these effects. RESULTS HIV+ women reported taking more NC-AE medications vs. HIV- women (P < 0.05). NC-AE medication use altogether was not associated with cognitive performance. However, among NC-AE medication subgroups, anticholinergic-acting medications, but not opioids or anxiolytics/anticonvulsants, were negatively associated with performance. HIV status moderated the association between these NC-AE medication subgroups and performance (P's < 0.05). HIV-serostatus differences (HIV- < HIV+) in global, learning, fluency, and motor function were greatest among women taking >1 anticholinergic medications. HIV-serostatus differences in performance on learning and psychomotor speed were also greatest among women taking 1 or more anxiolytics/anticonvulsants and 1 or more opioids, respectively. CONCLUSIONS HIV+ women have increased cognitive vulnerabilities to anticholinergic, anxiolytic/anticonvulsant, and opioid medications. Potential synergy between these medications and HIV may explain some HIV-related cognitive impairments. It may be important clinically to consider these specific types of medications as a contributor to impaired cognitive performance in HIV+ women and assess the cost/benefit of treatment dosage for underlying conditions.
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Affiliation(s)
- Leah H. Rubin
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Kendra K. Radtke
- Department of Clinical Pharmacy, University of California San Francisco School of Pharmacy, San Francisco, CA
| | - Seenae Eum
- Deparments of Experimental and Clinical Pharmacology and Psychiatry, University of Minnesota, Minneapolis, MN
| | - Bani Tamraz
- Deparments of Experimental and Clinical Pharmacology and Psychiatry, University of Minnesota, Minneapolis, MN
| | - Krithika N. Kumanan
- Department of Epidemiology and Biostatistics, School of Public Health, Univeristy of Illinois at Chicago, Chicago, IL
| | - Gayle Springer
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Pauline M. Maki
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL
- Department of Psychology, University of Illinois at Chicago, Chicago, IL
| | - Kathryn Anastos
- Department of Epidemiology & Population Health, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY
| | - Daniel Merenstein
- Department of Family Medicine, Georgetown University Medical Center, Washington, DC
| | - Roksana Karim
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Kathleen M. Weber
- Cook County Health & Hospital System/Hektoen Institute of Medicine, Chicago, IL
| | - Deborah Gustafson
- Department of Neurology, SUNY-Downstate Medical Center, Brooklyn, NY
| | - Ruth M. Greenblatt
- Department of Clinical Pharmacy, University of California San Francisco School of Pharmacy, San Francisco, CA
| | - Jeffrey R. Bishop
- Deparments of Experimental and Clinical Pharmacology and Psychiatry, University of Minnesota, Minneapolis, MN
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5
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Delgado-Vélez M, Lasalde-Dominicci JA. The Cholinergic Anti-Inflammatory Response and the Role of Macrophages in HIV-Induced Inflammation. Int J Mol Sci 2018; 19:ijms19051473. [PMID: 29772664 PMCID: PMC5983673 DOI: 10.3390/ijms19051473] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/11/2018] [Accepted: 04/29/2018] [Indexed: 12/20/2022] Open
Abstract
Macrophages are phagocytic immune cells that protect the body from foreign invaders and actively support the immune response by releasing anti- and proinflammatory cytokines. A seminal finding revolutionized the way macrophages are seen. The expression of the neuronal alpha7 nicotinic acetylcholine receptor (α7-nAChR) in macrophages led to the establishment of the cholinergic anti-inflammatory response (CAR) in which the activation of this receptor inactivates macrophage production of proinflammatory cytokines. This novel neuroimmune response soon began to emerge as a potential target to counteract inflammation during illness and infection states. Human immunodeficiency virus (HIV)-infected individuals suffer from chronic inflammation that persists even under antiretroviral therapy. Despite the CAR’s importance, few studies involving macrophages have been performed in the HIV field. Evidence demonstrates that monocyte-derived macrophages (MDMs) recovered from HIV-infected individuals are upregulated for α7-nAChR. Moreover, in vitro studies demonstrate that addition of an HIV viral constituent, gp120IIIB, to uninfected MDMs also upregulates the α7-nAChR. Importantly, contrary to what was expected, activation of upregulated α7-nAChRs in macrophages does not reduce inflammation, suggesting a CAR disruption. Although it is reasonable to consider this receptor as a pharmacological target, additional studies are necessary since its activity seems to differ from that observed in neurons.
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Affiliation(s)
- Manuel Delgado-Vélez
- Molecular Sciences Research Center, University of Puerto Rico, San Juan 00926, Puerto Rico.
| | - José A Lasalde-Dominicci
- Molecular Sciences Research Center, University of Puerto Rico, San Juan 00926, Puerto Rico.
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan 00931, Puerto Rico.
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan 00931, Puerto Rico.
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6
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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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7
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Muramatsu I, Uwada J, Masuoka T, Yoshiki H, Sada K, Lee KS, Nishio M, Ishibashi T, Taniguchi T. Regulation of synaptic acetylcholine concentrations by acetylcholine transport in rat striatal cholinergic transmission. J Neurochem 2017; 143:76-86. [PMID: 28700094 DOI: 10.1111/jnc.14127] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 06/17/2017] [Accepted: 06/29/2017] [Indexed: 11/29/2022]
Abstract
In addition to hydrolysis by acetylcholine esterase (AChE), acetylcholine (ACh) is also directly taken up into brain tissues. In this study, we examined whether the uptake of ACh is involved in the regulation of synaptic ACh concentrations. Superfusion experiments with rat striatal segments pre-incubated with [3 H]choline were performed using an ultra-mini superfusion vessel, which was developed to minimize superfusate retention within the vessel. Hemicholinium-3 (HC-3) at concentrations less than 1 μM, selectively inhibited the uptake of [3 H]choline by the high affinity-choline transporter 1 and had no effect on basal and electrically evoked [3 H]efflux in superfusion experiments. In contrast, HC-3 at higher concentrations, as well as tetraethylammonium (>10 μM), which inhibited the uptake of both [3 H]choline and [3 H]ACh, increased basal [3 H]overflow and potentiated electrically evoked [3 H]efflux. These effects of HC-3 and tetraethylammonium were also observed under conditions where tissue AChE was irreversibly inactivated by diisopropylfluorophosphate. Specifically, the potentiation of evoked [3 H]efflux was significantly higher in AChE-inactivated preparations and was attenuated by atropine. On the other hand, striatal segments pre-incubated with [3 H]ACh failed to increase [3 H]overflow in response to electrical stimulation. These results show that synaptic ACh concentrations are significantly regulated by the postsynaptic uptake of ACh, as well as by AChE hydrolysis and modulation of ACh release mediated through presynaptic muscarinic ACh receptors. In addition, these data suggest that the recycling of ACh-derived choline may be minor in cholinergic terminals. This study reveals a new mechanism of cholinergic transmission in the central nervous system.
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Affiliation(s)
- Ikunobu Muramatsu
- Department of Pharmacology, School of Medicine, Kanazawa Medical University, Uchinada, Ishikawa, Japan.,Division of Genomic Science and Microbiology, School of Medicine, University of Fukui, Eiheiji, Fukui, Japan.,Kimura Hospital, Awara, Fukui, Japan
| | - Junsuke Uwada
- Division of Cellular Signal Transduction, Department of Biochemistry, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | - Takayoshi Masuoka
- Department of Pharmacology, School of Medicine, Kanazawa Medical University, Uchinada, Ishikawa, Japan
| | - Hatsumi Yoshiki
- Division of Genomic Science and Microbiology, School of Medicine, University of Fukui, Eiheiji, Fukui, Japan
| | - Kiyonao Sada
- Division of Genomic Science and Microbiology, School of Medicine, University of Fukui, Eiheiji, Fukui, Japan
| | - Kung-Shing Lee
- Division of Genomic Science and Microbiology, School of Medicine, University of Fukui, Eiheiji, Fukui, Japan.,Department of Surgery, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Matomo Nishio
- Department of Pharmacology, School of Medicine, Kanazawa Medical University, Uchinada, Ishikawa, Japan
| | - Takaharu Ishibashi
- Department of Pharmacology, School of Medicine, Kanazawa Medical University, Uchinada, Ishikawa, Japan
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8
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Nookala AR, Mitra J, Chaudhari NS, Hegde ML, Kumar A. An Overview of Human Immunodeficiency Virus Type 1-Associated Common Neurological Complications: Does Aging Pose a Challenge? J Alzheimers Dis 2017; 60:S169-S193. [PMID: 28800335 PMCID: PMC6152920 DOI: 10.3233/jad-170473] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
With increasing survival of patients infected with human immunodeficiency virus type 1 (HIV-1), the manifestation of heterogeneous neurological complications is also increasing alarmingly in these patients. Currently, more than 30% of about 40 million HIV-1 infected people worldwide develop central nervous system (CNS)-associated dysfunction, including dementia, sensory, and motor neuropathy. Furthermore, the highly effective antiretroviral therapy has been shown to increase the prevalence of mild cognitive functions while reducing other HIV-1-associated neurological complications. On the contrary, the presence of neurological disorder frequently affects the outcome of conventional HIV-1 therapy. Although, both the children and adults suffer from the post-HIV treatment-associated cognitive impairment, adults, especially depending on the age of disease onset, are more prone to CNS dysfunction. Thus, addressing neurological complications in an HIV-1-infected patient is a delicate balance of several factors and requires characterization of the molecular signature of associated CNS disorders involving intricate cross-talk with HIV-1-derived neurotoxins and other cellular factors. In this review, we summarize some of the current data supporting both the direct and indirect mechanisms, including neuro-inflammation and genome instability in association with aging, leading to CNS dysfunction after HIV-1 infection, and discuss the potential strategies addressing the treatment or prevention of HIV-1-mediated neurotoxicity.
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Affiliation(s)
- Anantha Ram Nookala
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Joy Mitra
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA
| | - Nitish S. Chaudhari
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Muralidhar L. Hegde
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA
- Weill Cornell Medical College of Cornell University, NY, USA
| | - Anil Kumar
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO, USA
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9
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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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10
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Pittaluga A. Presynaptic Release-Regulating mGlu1 Receptors in Central Nervous System. Front Pharmacol 2016; 7:295. [PMID: 27630571 PMCID: PMC5006178 DOI: 10.3389/fphar.2016.00295] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 08/22/2016] [Indexed: 01/14/2023] Open
Abstract
Group I metabotropic glutamate (mGlu) receptors consists of mGlu1 and mGlu5 receptor subtypes. These receptors are widely distributed in the central nervous system (CNS), where they preferentially mediate facilitatory signaling in neurones and glial cells, mainly by favoring phospholipase (PLC) translocation. Based on the literature so far available, group I Metabotropic glutamate receptors (mGluRs) are preferentially expressed at the postsynaptic side of chemical synapsis, where they participate in the progression of the chemical stimulus. Studies, however, have shown the presence of these receptors also at the presynaptic level, where they exert several functions, including the modulation of transmitter exocytosis. Presynaptic Group I mGluRs can be both autoreceptors regulating release of glutamate and heteroreceptors regulating the release of various transmitters, including GABA, dopamine, noradrenaline, and acetylcholine. While the existence of presynaptic release-regulating mGlu5 receptors is largely recognized, the possibility that mGlu1 receptors also are present at this level has been a matter of discussion for a long time. A large body of evidence published in the last decade, however, supports this notion. This review aims at revisiting the data from in vitro studies concerning the existence and the role of release-regulating mGlu1 receptors presynaptically located in nerve terminals isolated from selected regions of the CNS. The functional interaction linking mGlu5 and mGlu1 receptor subtypes at nerve terminals and their relative contributions as modulators of central transmission will also be discussed. We apologize in advance for omission in our coverage of the existing literature.
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Affiliation(s)
- Anna Pittaluga
- Department of Pharmacy, Pharmacology and Toxicology Section, School of Medical and Pharmaceutical Sciences, University of GenoaGenoa, Italy
- Center of Excellence for Biomedical Research, University of GenoaGenoa, Italy
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11
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Nisticò R, Florenzano F, Mango D, Ferraina C, Grilli M, Di Prisco S, Nobili A, Saccucci S, D'Amelio M, Morbin M, Marchi M, Mercuri NB, Davis RJ, Pittaluga A, Feligioni M. Presynaptic c-Jun N-terminal Kinase 2 regulates NMDA receptor-dependent glutamate release. Sci Rep 2015; 5:9035. [PMID: 25762148 PMCID: PMC4357012 DOI: 10.1038/srep09035] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 02/13/2015] [Indexed: 12/17/2022] Open
Abstract
Activation of c-Jun N-terminal kinase (JNK) signaling pathway is a critical step for neuronal death occurring in several neurological conditions. JNKs can be activated via receptor tyrosine kinases, cytokine receptors, G-protein coupled receptors and ligand-gated ion channels, including the NMDA glutamate receptors. While JNK has been generally associated with postsynaptic NMDA receptors, its presynaptic role remains largely unexplored. Here, by means of biochemical, morphological and functional approaches, we demonstrate that JNK and its scaffold protein JIP1 are also expressed at the presynaptic level and that the NMDA-evoked glutamate release is controlled by presynaptic JNK-JIP1 interaction. Moreover, using knockout mice for single JNK isoforms, we proved that JNK2 is the essential isoform in mediating this presynaptic event. Overall the present findings unveil a novel JNK2 localization and function, which is likely to play a role in different physiological and pathological conditions.
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Affiliation(s)
- Robert Nisticò
- 1] Laboratory of Pharmacology of Synaptic Plasticity, EBRI "Rita Levi-Montalcini" Foundation, Rome, 00143, Italy [2] Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, 00185, Italy
| | - Fulvio Florenzano
- Laboratory of Pharmacology of Synaptic Plasticity, EBRI "Rita Levi-Montalcini" Foundation, Rome, 00143, Italy
| | - Dalila Mango
- 1] Laboratory of Pharmacology of Synaptic Plasticity, EBRI "Rita Levi-Montalcini" Foundation, Rome, 00143, Italy [2] Laboratory of Experimental Neurology, IRCCS Fondazione Santa Lucia, Rome, 00143, Italy
| | - Caterina Ferraina
- Laboratory of Pharmacology of Synaptic Plasticity, EBRI "Rita Levi-Montalcini" Foundation, Rome, 00143, Italy
| | - Massimo Grilli
- Department of Pharmacy, Pharmacology and Toxicology Section, University of Genoa, Genoa, 16148, Italy
| | - Silvia Di Prisco
- Department of Pharmacy, Pharmacology and Toxicology Section, University of Genoa, Genoa, 16148, Italy
| | - Annalisa Nobili
- 1] Laboratory of Experimental Neurology, IRCCS Fondazione Santa Lucia, Rome, 00143, Italy [2] University Campus Biomedico, 00100 Rome
| | - Stefania Saccucci
- Neuropathology &Neurology V - IRCCS Foundation C. Besta Milan, 20133, Italy
| | - Marcello D'Amelio
- 1] Laboratory of Experimental Neurology, IRCCS Fondazione Santa Lucia, Rome, 00143, Italy [2] University Campus Biomedico, 00100 Rome
| | - Michela Morbin
- Neuropathology &Neurology V - IRCCS Foundation C. Besta Milan, 20133, Italy
| | - Mario Marchi
- 1] Department of Pharmacy, Pharmacology and Toxicology Section, University of Genoa, Genoa, 16148, Italy [2] Center of Excellence for Biomedical Research, University of Genoa, Genoa, 16132, Italy
| | - Nicola B Mercuri
- Laboratory of Experimental Neurology, IRCCS Fondazione Santa Lucia, Rome, 00143, Italy
| | - Roger J Davis
- Department of Biochemistry and Molecular Biology, Howard Hughes Medical Institute and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, 01605, USA
| | - Anna Pittaluga
- 1] Department of Pharmacy, Pharmacology and Toxicology Section, University of Genoa, Genoa, 16148, Italy [2] Center of Excellence for Biomedical Research, University of Genoa, Genoa, 16132, Italy
| | - Marco Feligioni
- Laboratory of Pharmacology of Synaptic Plasticity, EBRI "Rita Levi-Montalcini" Foundation, Rome, 00143, Italy
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Brailoiu E, Deliu E, Sporici RA, Benamar K, Brailoiu GC. HIV-1-Tat excites cardiac parasympathetic neurons of nucleus ambiguus and triggers prolonged bradycardia in conscious rats. Am J Physiol Regul Integr Comp Physiol 2014; 306:R814-22. [PMID: 24694382 DOI: 10.1152/ajpregu.00529.2013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The mechanisms of autonomic imbalance and subsequent cardiovascular manifestations in HIV-1-infected patients are poorly understood. We report here that HIV-1 transactivator of transcription (Tat, fragment 1-86) produced a concentration-dependent increase in cytosolic Ca(2+) in cardiac-projecting parasympathetic neurons of nucleus ambiguus retrogradely labeled with rhodamine. Using store-specific pharmacological agents, we identified several mechanisms of the Tat-induced Ca(2+) elevation: 1) lysosomal Ca(2+) mobilization, 2) Ca(2+) release via inositol 1,4,5-trisphosphate-sensitive endoplasmic reticulum pools, and 3) Ca(2+) influx via transient receptor potential vanilloid type 2 (TRPV2) channels. Activation of TRPV2, nonselective cation channels, induced a robust and prolonged neuronal membrane depolarization, thus triggering an additional P/Q-mediated Ca(2+) entry. In vivo microinjection studies indicate a dose-dependent, prolonged bradycardic effect of Tat administration into the nucleus ambiguus of conscious rats, in which neuronal TRPV2 played a major role. Our results support previous studies, indicating that Tat promotes bradycardia and, consequently, may be involved in the QT interval prolongation reported in HIV-infected patients. In the context of an overall HIV-dependent autonomic dysfunction, these Tat-mediated mechanisms may account for the higher prevalence of sudden cardiac death in HIV-1-infected patients compared with general population with similar risk factors. Our results may be particularly relevant in view of the recent findings that significant Tat levels can still be identified in the cerebrospinal fluid of HIV-infected patients with viral load suppression due to efficient antiretroviral therapy.
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Affiliation(s)
- Eugen Brailoiu
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania; Center for Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Elena Deliu
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Romeo A Sporici
- Department of Internal Medicine, Brandywine Hospital, Coatesville, Pennsylvania
| | - Khalid Benamar
- Center for Substance Abuse, Temple University School of Medicine, Philadelphia, Pennsylvania; and
| | - G Cristina Brailoiu
- Department of Pharmaceutical Sciences, Thomas Jefferson University, Jefferson School of Pharmacy, Philadelphia, Pennsylvania
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13
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Bagashev A, Sawaya BE. Roles and functions of HIV-1 Tat protein in the CNS: an overview. Virol J 2013; 10:358. [PMID: 24359561 PMCID: PMC3879180 DOI: 10.1186/1743-422x-10-358] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/06/2013] [Indexed: 01/01/2023] Open
Abstract
Nearly 50% of HIV-infected individuals suffer from some form of HIV-associated neurocognitive disorders (HAND). HIV-1 Tat (a key HIV transactivator of transcription) protein is one of the first HIV proteins to be expressed after infection occurs and is absolutely required for the initiation of the HIV genome transcription. In addition to its canonical functions, various studies have shown the deleterious role of HIV-1 Tat in the development and progression of HAND. Within the CNS, only specific cell types can support productive viral replication (astrocytes and microglia), however Tat protein can be released form infected cells to affects HIV non-permissive cells such as neurons. Therefore, in this review, we will summarize the functions of HIV-1 Tat proteins in neural cells and its ability to promote HAND.
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Affiliation(s)
| | - Bassel E Sawaya
- Molecular Studies of Neurodegenerative Diseases Lab, The Fels Institute for Cancer Research & Molecular Biology, Philadelphia, PA 19140, USA.
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14
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Cao J, Wang S, Wang J, Cui W, Nesil T, Vigorito M, Chang SL, Li MD. RNA deep sequencing analysis reveals that nicotine restores impaired gene expression by viral proteins in the brains of HIV-1 transgenic rats. PLoS One 2013; 8:e68517. [PMID: 23874651 PMCID: PMC3712985 DOI: 10.1371/journal.pone.0068517] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Accepted: 05/06/2013] [Indexed: 01/06/2023] Open
Abstract
Persons infected with HIV-1 often develop neurologic disorders despite receiving highly active anti-retroviral therapy. Although the underlying mechanism is largely undetermined, our previous RNA-seq-based study showed that the expression of many genes was altered in the central nervous system (CNS) of HIV-1 transgenic (HIV-1Tg) rats. Because nicotine, a natural agonist of nicotinic acetylcholine receptors, exhibits a neuroprotective effect, we presently tested the hypothesis that nicotine restores the expression of altered genes in the CNS of HIV-1Tg rats. Adult male HIV-1Tg and F344 control strain rats were injected with either nicotine (0.25 mg/kg) or saline subcutaneously twice a day for 17 days. Gene expression in the prefrontal cortex (PFC), dorsal hippocampus (HIP), and dorsal striatum (STR) was evaluated using the RNA deep sequencing technique. We found that about 20% of the altered genes in the HIV-1Tg rat were affected by nicotine in each brain region, with the expression of most restored. Analysis of the restored genes showed distinct pathways corrected by nicotine in different brain regions of HIV-1Tg rats. Specifically, the two most significantly restored pathways were Wnt/β-catenin signaling and ephrin B signaling in the PFC, cAMP-responsive element-binding protein (CREB) signaling and glutathione metabolism pathway in the HIP, and tricarboxylic acid (TCA) cycle and calcium signaling in the STR. Together, our findings indicate that cholinergic modulators such as nicotine have beneficial effects on HIV-1-induced neurologic deficits.
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Affiliation(s)
- Junran Cao
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, Virginia, United States of America
| | - Shaolin Wang
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, Virginia, United States of America
| | - Ju Wang
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, Virginia, United States of America
- School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Wenyan Cui
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, Virginia, United States of America
- The First Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Tanseli Nesil
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, Virginia, United States of America
| | - Michael Vigorito
- Institute of NeuroImmune Pharmacology, Seton Hall University, South Orange, New Jersey, United States of America
- Department of Psychology, Seton Hall University, South Orange, New Jersey, United States of America
| | - Sulie L. Chang
- Institute of NeuroImmune Pharmacology, Seton Hall University, South Orange, New Jersey, United States of America
- Department of Biological Sciences, Seton Hall University, South Orange, New Jersey, United States of America
| | - Ming D. Li
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, Virginia, United States of America
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15
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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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16
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Giribaldi F, Milanese M, Bonifacino T, Anna Rossi PI, Di Prisco S, Pittaluga A, Tacchetti C, Puliti A, Usai C, Bonanno G. Group I metabotropic glutamate autoreceptors induce abnormal glutamate exocytosis in a mouse model of amyotrophic lateral sclerosis. Neuropharmacology 2012; 66:253-63. [PMID: 22634363 DOI: 10.1016/j.neuropharm.2012.05.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 04/26/2012] [Accepted: 05/13/2012] [Indexed: 10/28/2022]
Abstract
Glutamate-mediated excitotoxicity plays a major role in ALS and reduced astrocytic glutamate transport was suggested as a cause. Based on previous work we have proposed that abnormal release may represent another source of excessive glutamate. In this line, here we studied the modulation of glutamate release in ALS by Group I metabotropic glutamate (mGlu) receptors, that comprise mGlu1 and mGlu5 members. Synaptosomes from the lumbar spinal cord of SOD1/G93A mice, a widely used murine model for human ALS, and controls were used in release, confocal or electron microscopy and Western blot experiments. Concentrations of the mGlu1/5 receptor agonist 3,5-DHPG >0.3 μM stimulated the release of [(3)H]d- aspartate, used to label the releasing pools of glutamate, both in control and SOD1/G93A mice. At variance, ≤0.3 μM 3,5-DHPG increased [(3)H]d-aspartate release in SOD1/G93A mice only. Experiments with selective antagonists indicated the involvement of both mGlu1 and mGlu5 receptors, mGlu5 being preferentially involved in the high potency effects of 3,5-DHPG. High 3,5-DHPG concentrations increased IP3 formation in both mouse strains, whereas low 3,5-DHPG did it in SOD1/G93A mice only. Release experiments confirmed that 3,5-DHPG elicited [(3)H]d-aspartate exocytosis involving intra-terminal Ca(2+) release through IP3-sensitive channels. Confocal microscopy indicated the co-existence of both receptors presynaptically in the same glutamatergic nerve terminal in SOD1/G93A mice. To conclude, activation of mGlu1/5 receptors produced abnormal glutamate release in SOD1/G93A mice, suggesting that these receptors are implicated in ALS and that selective antagonists may be predicted for new therapeutic approaches. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Francesco Giribaldi
- Department of Experimental Medicine Pharmacology and Toxicology Unit, University of Genoa, Genoa, Italy
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17
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Musante V, Summa M, Neri E, Puliti A, Godowicz TT, Severi P, Battaglia G, Raiteri M, Pittaluga A. The HIV-1 Viral Protein Tat Increases Glutamate and Decreases GABA Exocytosis from Human and Mouse Neocortical Nerve Endings. Cereb Cortex 2009; 20:1974-84. [DOI: 10.1093/cercor/bhp274] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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18
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Influence of Integrin-blocking Peptide on Gadolinium- and Hypertonic Shrinking-induced Neurotransmitter Release in Rat Brain Synaptosomes. Neurochem Res 2008; 33:1316-24. [DOI: 10.1007/s11064-007-9585-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Accepted: 12/27/2007] [Indexed: 11/26/2022]
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19
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Abstract
Glutamate and GABA, the two most abundant neurotransmitters in the mammalian central nervous system, can act on metabotropic receptors that are structurally quite dissimilar from those targeted by most other neurotransmitters/modulators. Accordingly, metabotropic glutamate receptors (mGluRs) and GABA(B) receptors (GABA(B)Rs) are classified as members of family 3 (or family C) of G protein-coupled receptors. On the other hand, mGluRs and GABA(B)Rs exhibit pronounced and partly unresolved differences between each other. The most intriguing difference is that mGluRs exist as multiple pharmacologically as well as structurally distinct subtypes, whereas, in the case of GABA(B)Rs, molecular biologists have so far identified only one structurally distinct heterodimeric complex whose few variants seem unable to explain the pharmacological heterogeneity of GABA(B)Rs observed in many functional studies. Both mGluRs and GABA(B)Rs can be localized on axon terminals of different neuronal systems as presynaptic autoreceptors and heteroreceptors modulating the exocytosis of various transmitters.
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Affiliation(s)
- M Raiteri
- Department of Experimental Medicine, Pharmacology and Toxicology Section, University of Genoa, 16148 Genoa, Italy.
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20
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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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21
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Luccini E, Musante V, Neri E, Brambilla Bas M, Severi P, Raiteri M, Pittaluga A. Functional interactions between presynaptic NMDA receptors and metabotropic glutamate receptors co-expressed on rat and human noradrenergic terminals. Br J Pharmacol 2007; 151:1087-94. [PMID: 17592518 PMCID: PMC2042940 DOI: 10.1038/sj.bjp.0707280] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND AND PURPOSE Electrophysiological studies described potentiation of NMDA receptor function by metabotropic glutamate receptors (mGluRs) of group I occurring postsynaptically. Since release-enhancing NMDA receptors exist on noradrenergic terminals and group I mGluRs have recently been identified on these nerve endings, we have investigated if NMDA receptor-mGluR interactions also can occur at the presynaptic level. EXPERIMENTAL APPROACH Rat hippocampus and human neocortex synaptosomes were labelled with [(3)H]noradrenaline and superfused with mGluR agonists and antagonists. NMDA-evoked [(3)H]noradrenaline release was produced by removal of external Mg(2+) or by simultaneous application of NMDA and AMPA in Mg(2+)-containing solutions. KEY RESULTS The mGluR1/5 agonist 3,5-DHPG, inactive on its own, potentiated both the release of [(3)H]noradrenaline elicited by AMPA/NMDA/glycine and that evoked by NMDA/glycine following Mg(2+) removal. The effect of 3,5-DHPG on the AMPA/NMDA/glycine-induced release was insensitive to the mGluR1 antagonist CPCCOEt, but it was abolished by the mGluR5 antagonist MPEP; moreover, it was potentiated by the mGluR5 positive allosteric modulator DFB. When NMDA receptors were activated by Mg(2+) removal, both mGluR5 and mGluR1 contributed to the evoked release, the mGluR-mediated release being blocked only by CPCCOEt and MPEP in combination. Experiments with human neocortex synaptosomes show NMDA receptor-mGluR interactions qualitatively similar to those observed in rodents. CONCLUSIONS AND IMPLICATIONS Group I mGluRs, both of the mGluR1 and mGluR5 subtypes, co-localize with NMDA receptors on noradrenergic terminals of rat hippocampus and human neocortex. Depending on the mode of activation, NMDA receptors exert differential permissive roles on the activation of presynaptic mGluR1 and mGluR5.
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MESH Headings
- Animals
- Cerebral Cortex/drug effects
- Cerebral Cortex/metabolism
- Cerebral Cortex/physiology
- Chromones/pharmacology
- Female
- Glycine/analogs & derivatives
- Glycine/pharmacology
- Hippocampus/drug effects
- Hippocampus/metabolism
- Hippocampus/physiology
- Humans
- Male
- N-Methylaspartate/pharmacology
- Norepinephrine/metabolism
- Norepinephrine/pharmacology
- Presynaptic Terminals/drug effects
- Presynaptic Terminals/metabolism
- Presynaptic Terminals/physiology
- Protein Binding/drug effects
- Rats
- Rats, Sprague-Dawley
- Receptor Cross-Talk/drug effects
- Receptor Cross-Talk/physiology
- Receptor, Metabotropic Glutamate 5
- Receptors, AMPA/metabolism
- Receptors, AMPA/physiology
- Receptors, Metabotropic Glutamate/metabolism
- Receptors, Metabotropic Glutamate/physiology
- Receptors, N-Methyl-D-Aspartate/metabolism
- Receptors, N-Methyl-D-Aspartate/physiology
- Receptors, Presynaptic/metabolism
- Receptors, Presynaptic/physiology
- Resorcinols/pharmacology
- Synaptosomes/drug effects
- Synaptosomes/metabolism
- Synaptosomes/physiology
- Tritium
- alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/pharmacology
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Affiliation(s)
- E Luccini
- Pharmacology and Toxicology Section, Department of Experimental Medicine, University of Genoa Genoa, Italy
| | - V Musante
- Pharmacology and Toxicology Section, Department of Experimental Medicine, University of Genoa Genoa, Italy
| | - E Neri
- Pharmacology and Toxicology Section, Department of Experimental Medicine, University of Genoa Genoa, Italy
| | | | - P Severi
- Division of Neurosurgery, Galliera Hospital Genoa, Italy
| | - M Raiteri
- Pharmacology and Toxicology Section, Department of Experimental Medicine, University of Genoa Genoa, Italy
- Center of Excellence for Biomedical Research, University of Genoa Genoa, Italy
| | - A Pittaluga
- Pharmacology and Toxicology Section, Department of Experimental Medicine, University of Genoa Genoa, Italy
- Center of Excellence for Biomedical Research, University of Genoa Genoa, Italy
- Author for correspondence:
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22
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Neri E, Musante V, Pittaluga A. Effects of the HIV-1 viral protein TAT on central neurotransmission: role of group I metabotropic glutamate receptors. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2007; 82:339-56. [PMID: 17678970 DOI: 10.1016/s0074-7742(07)82018-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Human immunodeficiency virus 1 (HIV-1)-associated dementia (HAD) represents a common complication of HIV-1 infection. Antiretroviral therapy has diminished its incidence, but it is insufficient to eradicate the problem. HAD depends on the presence of the virus in central nervous system (CNS), but the molecular mechanisms involved are not completely understood. It is widely accepted that proteins shed by the virus, such as the envelope glycoprotein gp120 and the nonstructural viral protein Tat, may themselves cause alterations to CNS. By one side, viral proteins are toxic to neurons because of their ability (1) to act as excitotoxins and (2) to evoke the release of endogenous neurotoxins and/or proinflammatory cytokines. By the other side, evidences are emerging that viral components can alter neuronal functions either by modifying the release of neurotransmitters or by influencing the functions of classical receptors controlling central neurotransmission. We here review some results concerning the effects of Tat on cholinergic and noradrenergic neurotransmission in human and rat cortex. The protein can induce the release of acetylcholine from both human and rat cortical cholinergic nerve terminals in a specie-specific manner. In human cholinergic terminals, Tat-mediated releasing effect depends on activation of receptors belonging to I group of metabotropic glutamate receptors (mGluRs), while in rat terminals Tat-induced effect involves the activation of a so far unknown receptor. The protein, unable on its own to release noradrenaline from human and rat cortical noradrenergic nerve endings, potentiates the release of amine induced by presynaptic NMDA receptors. Also in this case, Tat effect involves activation of a receptor belonging to the group I mGluRs, in particular of the mGluR1 subtype. The finding that group I mGluRs may represent a preferential target of the protein in CNS may be relevant to the proposal of new therapeutic approaches for the cure of HAD.
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Affiliation(s)
- Elisa Neri
- Department of Experimental Medicine, Pharmacology and Toxicology Section, University of Genova, Genova, Italy
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23
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Abstract
Most neurological and psychiatric disorders involve selective or preferential impairments of neurotransmitter systems. Therefore, studies of functional transmitter pathophysiology in human brain are of unique importance in view of the development of effective, mechanism-based, therapeutic modalities. It is well known that central nervous system functional proteins, including receptors, transporters, ion channels, and enzymes, can exhibit high heterogeneity in terms of structure, function, and pharmacological profile. If the existence of types and subtypes of functional proteins amplifies the possibility of developing selective drugs, such heterogeneity certainly increases the likelihood of interspecies differences. It is therefore essential, before choosing animal models to be used in preclinical pharmacology experimentation, to establish whether functionally corresponding proteins in men and animals also display identical pharmacological profiles. Because of evidence that scaffolding proteins, trafficking between plasma membrane and intracellular pools, phosphorylation and allosteric modulators can affect the function of receptors and transporters, experiments with human clones expressed in host cells where the environment of native receptors is rarely reproduced should be interpreted with caution. Thus, the use of neurosurgically removed fresh human brain tissue samples in which receptors, transporters, ion channels, and enzymes essentially retain their natural environment represents a unique experimental approach to enlarge our understanding of human brain processes and to help in the choice of appropriate animal models. Using this experimental approach, many human brain functional proteins, in particular transmitter receptors, have been characterized in terms of localization, function, and pharmacological properties.
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Affiliation(s)
- Maurizio Raiteri
- Dipartimento di Medicina Sperimentale, Sezione di Farmacologia e Tossicologia, Viale Cembrano 4, 16148 Genova, Italy.
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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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Dietz GPH, Bähr M. Delivery of bioactive molecules into the cell: the Trojan horse approach. Mol Cell Neurosci 2005; 27:85-131. [PMID: 15485768 DOI: 10.1016/j.mcn.2004.03.005] [Citation(s) in RCA: 358] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2003] [Revised: 02/17/2004] [Accepted: 03/16/2004] [Indexed: 01/12/2023] Open
Abstract
In recent years, vast amounts of data on the mechanisms of neural de- and regeneration have accumulated. However, only in disproportionally few cases has this led to efficient therapies for human patients. Part of the problem is to deliver cell death-averting genes or gene products across the blood-brain barrier (BBB) and cellular membranes. The discovery of Antennapedia (Antp)-mediated transduction of heterologous proteins into cells in 1992 and other "Trojan horse peptides" raised hopes that often-frustrating attempts to deliver proteins would now be history. The demonstration that proteins fused to the Tat protein transduction domain (PTD) are capable of crossing the BBB may revolutionize molecular research and neurobiological therapy. However, it was only recently that PTD-mediated delivery of proteins with therapeutic potential has been achieved in models of neural degeneration in nerve trauma and ischemia. Several groups have published the first positive results using protein transduction domains for the delivery of therapeutic proteins in relevant animal models of human neurological disorders. Here, we give an extensive review of peptide-mediated protein transduction from its early beginnings to new advances, discuss their application, with particular focus on a critical evaluation of the limitations of the method, as well as alternative approaches. Besides applications in neurobiology, a large number of reports using PTD in other systems are included as well. Because each protein requires an individual purification scheme that yields sufficient quantities of soluble, transducible material, the neurobiologist will benefit from the experiences of other researchers in the growing field of protein transduction.
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Behnisch T, Francesconi W, Sanna PP. HIV secreted protein Tat prevents long-term potentiation in the hippocampal CA1 region. Brain Res 2004; 1012:187-9. [PMID: 15158177 DOI: 10.1016/j.brainres.2004.03.037] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2004] [Indexed: 10/26/2022]
Abstract
HIV-associated dementia (HAD) is a complication of advanced HIV disease. Both viral products and host cytokines are believed to be involved in the pathogenesis of HIV-associated neurological manifestations. Among the viral products released by HIV-infected cells is the soluble protein Tat. We investigated the effect of exposure of organotypic hippocampal slices to 100 nM recombinant Tat 1-86 on long-term potentiation (LTP) of field excitatory postsynaptic potential (fEPSP) at Schaffer collateral/commissural fiber-CA1 synapses. Exposure to Tat 1-86 prevented the induction of LTP without affecting post-tetanic potentiation. Tat 1-72delta31-61, which lacks the neurotoxic domain of Tat, had no significant effect on LTP. Tat's ability to disrupt synaptic plasticity may be relevant to the pathogenesis of the cognitive impairments seen in patients with HIV disease.
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Affiliation(s)
- Thomas Behnisch
- Department of Neurophysiology, Leibniz Institute for Neurobiology, Brennecke Str. 6, 39118 Magdeburg, Germany.
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