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Jiménez-Torres AC, Porter KD, Hastie JA, Adeniran C, Moukha-Chafiq O, Nguyen TH, Ananthan S, Augelli-Szafran CE, Zhan CG, Zhu J. Effects of SRI-32743, a Novel Quinazoline Structure-Based Compound, on HIV-1 Tat and Cocaine Interaction with Norepinephrine Transporter. Int J Mol Sci 2024; 25:7881. [PMID: 39063123 PMCID: PMC11277056 DOI: 10.3390/ijms25147881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2024] [Revised: 07/12/2024] [Accepted: 07/15/2024] [Indexed: 07/28/2024] Open
Abstract
Prolonged exposure to HIV-1 transactivator of transcription (Tat) protein dysregulates monoamine transmission, a physiological change implicated as a key factor in promoting neurocognitive disorders among people living with HIV. We have demonstrated that in vivo expression of Tat in Tat transgenic mice decreases dopamine uptake through both dopamine transporter (DAT) and norepinephrine transporter (NET) in the prefrontal cortex. Further, our novel allosteric inhibitor of monoamine transporters, SRI-32743, has been shown to attenuate Tat-inhibited dopamine transport through DAT and alleviates Tat-potentiated cognitive impairments. The current study reports the pharmacological profiles of SRI-32743 in basal and Tat-induced inhibition of human NET (hNET) function. SRI-32743 exhibited less affinity for hNET binding than desipramine, a classical NET inhibitor, but displayed similar potency for inhibiting hDAT and hNET activity. SRI-32743 concentration-dependently increased hNET affinity for [3H]DA uptake but preserved the Vmax of dopamine transport. SRI-32743 slowed the cocaine-mediated dissociation of [3H]Nisoxetine binding and reduced both [3H]DA and [3H]MPP+ efflux but did not affect d-amphetamine-mediated [3H]DA release through hNET. Finally, we determined that SRI-32743 attenuated a recombinant Tat1-86-induced decrease in [3H]DA uptake via hNET. Our findings demonstrated that SRI-32743 allosterically disrupts the recombinant Tat1-86-hNET interaction, suggesting a potential treatment for HIV-infected individuals with concurrent cocaine abuse.
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Affiliation(s)
- Ana Catya Jiménez-Torres
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, 715 Sumter Street, Columbia, SC 29208, USA; (A.C.J.-T.); (K.D.P.); (J.A.H.)
| | - Katherine D. Porter
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, 715 Sumter Street, Columbia, SC 29208, USA; (A.C.J.-T.); (K.D.P.); (J.A.H.)
| | - Jamison A. Hastie
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, 715 Sumter Street, Columbia, SC 29208, USA; (A.C.J.-T.); (K.D.P.); (J.A.H.)
| | - Charles Adeniran
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA; (C.A.); (C.-G.Z.)
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
| | - Omar Moukha-Chafiq
- Department of Chemistry, Scientific Platforms Division, Southern Research, Birmingham, AL 35205, USA; (O.M.-C.); (T.H.N.); (S.A.); (C.E.A.-S.)
| | - Theresa H. Nguyen
- Department of Chemistry, Scientific Platforms Division, Southern Research, Birmingham, AL 35205, USA; (O.M.-C.); (T.H.N.); (S.A.); (C.E.A.-S.)
| | - Subramaniam Ananthan
- Department of Chemistry, Scientific Platforms Division, Southern Research, Birmingham, AL 35205, USA; (O.M.-C.); (T.H.N.); (S.A.); (C.E.A.-S.)
| | - Corinne E. Augelli-Szafran
- Department of Chemistry, Scientific Platforms Division, Southern Research, Birmingham, AL 35205, USA; (O.M.-C.); (T.H.N.); (S.A.); (C.E.A.-S.)
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA; (C.A.); (C.-G.Z.)
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
| | - Jun Zhu
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, 715 Sumter Street, Columbia, SC 29208, USA; (A.C.J.-T.); (K.D.P.); (J.A.H.)
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Lark AR, Nass SR, Hahn YK, Gao B, Milne GL, Knapp PE, Hauser KF. HIV-1 Tat and morphine interactions dynamically shift striatal monoamine levels and exploratory behaviors over time. J Neurochem 2024; 168:185-204. [PMID: 38308495 PMCID: PMC10922901 DOI: 10.1111/jnc.16057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 12/28/2023] [Accepted: 01/10/2024] [Indexed: 02/04/2024]
Abstract
Despite the advent of combination anti-retroviral therapy (cART), nearly half of people infected with HIV treated with cART still exhibit HIV-associated neurocognitive disorders (HAND). HAND can be worsened by co-morbid opioid use disorder. The basal ganglia are particularly vulnerable to HIV-1 and exhibit higher viral loads and more severe pathology, which can be exacerbated by co-exposure to opioids. Evidence suggests that dopaminergic neurotransmission is disrupted by HIV exposure, however, little is known about whether co-exposure to opioids may alter neurotransmitter levels in the striatum and if this in turn influences behavior. Therefore, we assayed motor, anxiety-like, novelty-seeking, exploratory, and social behaviors, and levels of monoamines and their metabolites following 2 weeks and 2 months of Tat and/or morphine exposure in transgenic mice. Morphine decreased dopamine levels, but significantly elevated norepinephrine, the dopamine metabolites dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and the serotonin metabolite 5-hydroxyindoleacetic acid, which typically correlated with increased locomotor behavior. The combination of Tat and morphine altered dopamine, DOPAC, and HVA concentrations differently depending on the neurotransmitter/metabolite and duration of exposure but did not affect the numbers of tyrosine hydroxylase-positive neurons in the mesencephalon. Tat exposure increased the latency to interact with novel conspecifics, but not other novel objects, suggesting the viral protein inhibits exploratory behavior initiation in a context-dependent manner. By contrast, and consistent with prior findings that opioid misuse can increase novelty-seeking behavior, morphine exposure increased the time spent exploring a novel environment. Finally, Tat and morphine interacted to affect locomotor activity in a time-dependent manner, while grip strength and rotarod performance were unaffected. Together, our results provide novel insight into the unique effects of HIV-1 Tat and morphine on monoamine neurochemistry that may underlie their divergent effects on motor and exploratory behavior.
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Affiliation(s)
| | | | | | - Benlian Gao
- Neurochemistry Core, Vanderbilt Brain Institute, Vanderbilt University
| | - Ginger L. Milne
- Neurochemistry Core, Vanderbilt Brain Institute, Vanderbilt University
| | - Pamela E. Knapp
- Department of Pharmacology & Toxicology
- Department of Anatomy and Neurobiology
- Institute for Drug and Alcohol Studies, Virginia Commonwealth University
| | - Kurt F. Hauser
- Department of Pharmacology & Toxicology
- Department of Anatomy and Neurobiology
- Institute for Drug and Alcohol Studies, Virginia Commonwealth University
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Nepal B, Das S, Reith ME, Kortagere S. Overview of the structure and function of the dopamine transporter and its protein interactions. Front Physiol 2023; 14:1150355. [PMID: 36935752 PMCID: PMC10020207 DOI: 10.3389/fphys.2023.1150355] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 02/21/2023] [Indexed: 03/06/2023] Open
Abstract
The dopamine transporter (DAT) plays an integral role in dopamine neurotransmission through the clearance of dopamine from the extracellular space. Dysregulation of DAT is central to the pathophysiology of numerous neuropsychiatric disorders and as such is an attractive therapeutic target. DAT belongs to the solute carrier family 6 (SLC6) class of Na+/Cl- dependent transporters that move various cargo into neurons against their concentration gradient. This review focuses on DAT (SCL6A3 protein) while extending the narrative to the closely related transporters for serotonin and norepinephrine where needed for comparison or functional relevance. Cloning and site-directed mutagenesis experiments provided early structural knowledge of DAT but our contemporary understanding was achieved through a combination of crystallization of the related bacterial transporter LeuT, homology modeling, and subsequently the crystallization of drosophila DAT. These seminal findings enabled a better understanding of the conformational states involved in the transport of substrate, subsequently aiding state-specific drug design. Post-translational modifications to DAT such as phosphorylation, palmitoylation, ubiquitination also influence the plasma membrane localization and kinetics. Substrates and drugs can interact with multiple sites within DAT including the primary S1 and S2 sites involved in dopamine binding and novel allosteric sites. Major research has centered around the question what determines the substrate and inhibitor selectivity of DAT in comparison to serotonin and norepinephrine transporters. DAT has been implicated in many neurological disorders and may play a role in the pathology of HIV and Parkinson's disease via direct physical interaction with HIV-1 Tat and α-synuclein proteins respectively.
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Affiliation(s)
- Binod Nepal
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Sanjay Das
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Maarten E. Reith
- Department of Psychiatry, New York University School of Medicine, New York City, NY, United States
| | - Sandhya Kortagere
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- *Correspondence: Sandhya Kortagere,
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League AF, Gorman BL, Hermes DJ, Johnson CT, Jacobs IR, Yadav-Samudrala BJ, Poklis JL, Niphakis MJ, Cravatt BF, Lichtman AH, Ignatowska-Jankowska BM, Fitting S. Monoacylglycerol Lipase Inhibitor MJN110 Reduces Neuronal Hyperexcitability, Restores Dendritic Arborization Complexity, and Regulates Reward-Related Behavior in Presence of HIV-1 Tat. Front Neurol 2021; 12:651272. [PMID: 34484091 PMCID: PMC8415271 DOI: 10.3389/fneur.2021.651272] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 07/12/2021] [Indexed: 12/01/2022] Open
Abstract
While current therapeutic strategies for people living with human immunodeficiency virus type 1 (HIV-1) suppress virus replication peripherally, viral proteins such as transactivator of transcription (Tat) enter the central nervous system early upon infection and contribute to chronic inflammatory conditions even alongside antiretroviral treatment. As demand grows for supplemental strategies to combat virus-associated pathology presenting frequently as HIV-associated neurocognitive disorders (HAND), the present study aimed to characterize the potential utility of inhibiting monoacylglycerol lipase (MAGL) activity to increase inhibitory activity at cannabinoid receptor-type 1 receptors through upregulation of 2-arachidonoylglycerol (2-AG) and downregulation of its degradation into proinflammatory metabolite arachidonic acid (AA). The MAGL inhibitor MJN110 significantly reduced intracellular calcium and increased dendritic branching complexity in Tat-treated primary frontal cortex neuron cultures. Chronic MJN110 administration in vivo increased 2-AG levels in the prefrontal cortex (PFC) and striatum across Tat(+) and Tat(–) groups and restored PFC N-arachidonoylethanolamine (AEA) levels in Tat(+) subjects. While Tat expression significantly increased rate of reward-related behavioral task acquisition in a novel discriminative stimulus learning and cognitive flexibility assay, MJN110 altered reversal acquisition specifically in Tat(+) mice to rates indistinguishable from Tat(–) controls. Collectively, our results suggest a neuroprotective role of MAGL inhibition in reducing neuronal hyperexcitability, restoring dendritic arborization complexity, and mitigating neurocognitive alterations driven by viral proteins associated with latent HIV-1 infection.
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Affiliation(s)
- Alexis F League
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
| | - Benjamin L Gorman
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
| | - Douglas J Hermes
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
| | - Clare T Johnson
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
| | - Ian R Jacobs
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
| | - Barkha J Yadav-Samudrala
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
| | - Justin L Poklis
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | - Micah J Niphakis
- Department of Chemistry, Scripps Research Institute, La Jolla, CA, United States
| | - Benjamin F Cravatt
- Department of Chemistry, Scripps Research Institute, La Jolla, CA, United States
| | - Aron H Lichtman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | | | - Sylvia Fitting
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, Chapel Hill, NC, United States
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Umezu T. Identification of novel target molecules of l-menthol. Heliyon 2021; 7:e07329. [PMID: 34195432 PMCID: PMC8237303 DOI: 10.1016/j.heliyon.2021.e07329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 05/03/2021] [Accepted: 06/11/2021] [Indexed: 12/11/2022] Open
Abstract
The present study used a binding assay to identify novel target biomolecules of l-menthol ([−]-menthol) that promote mouse ambulation. Among 88 different ligands to specific biomolecules examined, 0.1 mM l-menthol inhibited the binding of 13 ligands with relatively high inhibition rates. The assays showed that l-menthol acts on calcium channels, sodium channels, γ-aminobutyric acid type A (GABAA) receptor, GABA transporter, dopamine transporter, dopamine D4 receptor, adenosine A2a receptor, α2A-adrenergic receptor, histamine H2 receptor, bombesin receptor, angiotensin AT1 receptor, vasopressin V2 receptor, and leukotriene B4 receptor over a similar concentration range. The inhibition constant (Ki) for l-menthol inhibition of binding of [3H]-WIN35,428 to the human recombinant dopamine transporter was 6.15 × 10−4 mol/L. The Ki for l-menthol inhibition of binding of [3H]-ethynylbicycloorthobenzoate (EBOB), a ligand of GABAA receptor picrotoxin site, was 2.88 × 10−4 mol/L. These results should aid future research by providing clues for investigating the mechanisms underlying l-menthol activities, including the ambulation-promoting effect. The present results suggest that the dopamine transporter, adenosine A2a receptor, dopamine D4 receptor, α2A-adrenergic receptor, and GABAA receptor are promising candidate molecules that are involved in the mechanisms underlying the psychostimulant-like effect of l-menthol.
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Affiliation(s)
- Toyoshi Umezu
- Health and Environmental Risk Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
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6
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Adeniran C, Yuan Y, Davis SE, Lin C, Xu J, Zhu J, Zhan CG. Binding Mode of Human Norepinephrine Transporter Interacting with HIV-1 Tat. ACS Chem Neurosci 2021; 12:1519-1527. [PMID: 33886267 PMCID: PMC8562539 DOI: 10.1021/acschemneuro.0c00792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The increase of HIV infection in macrophages results in HIV proteins being released, like HIV Tat which impairs the function of monoamine transporters. HIV-infected patients have displayed increased synaptic levels of dopamine (DA) due to reduced binding and function of monoamine transporters such as the norepinephrine transporter (NET) and the dopamine transporter (DAT). Development of a three-dimensional model of the HIV-1 Tat-human NET (hNET) binding complex would help reveal how HIV-1 Tat causes toxicity in the neuron by affecting DA uptake. Here we use computational techniques such as molecular modeling to study microscopic properties and molecular dynamics of the HIV-1 Tat-hNET binding. These modeling techniques allow us to analyze noncovalent interactions and observe residue-residue contacts to verify a model structure. The modeling results studied here show that HIV-1 Tat-hNET binding is highly dynamic and that HIV-1 Tat preferentially binds to hNET in its outward-open state. In particular, HIV-1 Tat forms hydrogen bond interactions with side chains of hNET residues Y84, K88, and T544. The favorable hydrogen bonding interactions of HIV-1 Tat with the hNET side chain residues Y84 and T544 have been validated by our subsequently performed DA uptake activity assays and site-directed mutagenesis, suggesting that the modeled HIV-1 Tat-hNET binding mode is reasonable. These mechanistic and structural insights gained through homology models discussed in this study are expected to encourage the pursuit of pharmacological and biochemical studies on HIV-1 Tat interacting with hNET mechanisms and detailed structures.
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Affiliation(s)
- Charles Adeniran
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536
- Department of Chemistry, University of Kentucky, 505 Rose Street, Lexington, KY 40506
| | - Yaxia Yuan
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536
| | - Sarah E. Davis
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - Ciai Lin
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - Jiahui Xu
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - Jun Zhu
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208
| | - Chang-Guo Zhan
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536
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Mutations of Human DopamineTransporter at Tyrosine88, Aspartic Acid206, and Histidine547 Influence Basal and HIV-1 Tat-inhibited Dopamine Transport. J Neuroimmune Pharmacol 2021; 16:854-869. [PMID: 33537927 PMCID: PMC8329121 DOI: 10.1007/s11481-021-09984-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/13/2021] [Indexed: 12/14/2022]
Abstract
HIV-1 transactivator of transcription (Tat) has a great impact on the development of HIV-1 associated neurocognitive disorders through disrupting dopamine transmission. This study determined the mutational effects of human dopamine transporter (hDAT) on basal and Tat-induced inhibition of dopamine transport. Compared to wild-type hDAT, the maximal velocity (Vmax) of [3H]dopamine uptake was decreased in D381L and Y88F/D206L/H547A, increased in D206L/H547A, and unaltered in D206L. Recombinant TatR1 − 86 inhibited dopamine uptake in wild-type hDAT, which was attenuated in either DAT mutants (D206L, D206L/H547A, and Y88F/D206L/H547A) or mutated TatR1 − 86 (K19A and C22G), demonstrating perturbed Tat-DAT interaction. Mutational effects of hDAT on the transporter conformation were evidenced by attenuation of zinc-induced increased [3H]WIN35,428 binding in D206L/H547A and Y88F/D206A/H547A and enhanced basal MPP+ efflux in D206L/H547A. H547A-induced outward-open transport conformational state was further validated by enhanced accessibility to MTSET ([2-(trimethylammonium)ethyl]-methanethiosulfonate) of an inserted cysteine (I159C) on a hDAT background.. Furthermore, H547A displayed an increase in palmitoylation inhibitor-induced inhibition of dopamine uptake relative to wide-type hDAT, indicating a change in basal palmitoylation in H547A. These results demonstrate that Y88F, D206L, and H547A attenuate Tat inhibition while preserving DA uptake, providing insights into identifying targets for improving DAT-mediated dopaminergic dysregulation.
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Hermes DJ, Jacobs IR, Key MC, League AF, Yadav-Samudrala BJ, Xu C, McLane VD, Nass SR, Jiang W, Meeker RB, Ignatowska-Jankowska BM, Lichtman AH, Li Z, Wu Z, Yuan H, Knapp PE, Hauser KF, Fitting S. Escalating morphine dosing in HIV-1 Tat transgenic mice with sustained Tat exposure reveals an allostatic shift in neuroinflammatory regulation accompanied by increased neuroprotective non-endocannabinoid lipid signaling molecules and amino acids. J Neuroinflammation 2020; 17:345. [PMID: 33208151 PMCID: PMC7672881 DOI: 10.1186/s12974-020-01971-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 09/29/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Human immunodeficiency virus type-1 (HIV-1) and opiates cause long-term inflammatory insult to the central nervous system (CNS) and worsen disease progression and HIV-1-related neuropathology. The combination of these proinflammatory factors reflects a devastating problem as opioids have high abuse liability and continue to be prescribed for certain patients experiencing HIV-1-related pain. METHODS Here, we examined the impact of chronic (3-month) HIV-1 transactivator of transcription (Tat) exposure to short-term (8-day), escalating morphine in HIV-1 Tat transgenic mice that express the HIV-1 Tat protein in a GFAP promoter-regulated, doxycycline (DOX)-inducible manner. In addition to assessing morphine-induced tolerance in nociceptive responses organized at spinal (i.e., tail-flick) and supraspinal (i.e., hot-plate) levels, we evaluated neuroinflammation via positron emission tomography (PET) imaging using the [18F]-PBR111 ligand, immunohistochemistry, and cytokine analyses. Further, we examined endocannabinoid (eCB) levels, related non-eCB lipids, and amino acids via mass spectrometry. RESULTS: Tat-expressing [Tat(+)] transgenic mice displayed antinociceptive tolerance in the tail withdrawal and hot-plate assays compared to control mice lacking Tat [Tat(-)]. This tolerance was accompanied by morphine-dependent increases in Iba-1 ± 3-nitrotryosine immunoreactive microglia, and alterations in pro- and anti-inflammatory cytokines, and chemokines in the spinal cord and striatum, while increases in neuroinflammation were absent by PET imaging of [18F]-PBR111 uptake. Tat and morphine exposure differentially affected eCB levels, non-eCB lipids, and specific amino acids in a region-dependent manner. In the striatum, non-eCB lipids were significantly increased by short-term, escalating morphine exposure, including peroxisome proliferator activator receptor alpha (PPAR-α) ligands N-oleoyl ethanolamide (OEA) and N-palmitoyl ethanolamide (PEA), as well as the amino acids phenylalanine and proline. In the spinal cord, Tat exposure increased amino acids leucine and valine, while morphine decreased levels of tyrosine and valine but did not affect eCBs or non-eCB lipids. CONCLUSION Overall results demonstrate that 3 months of Tat exposure increased morphine tolerance and potentially innate immune tolerance evidenced by reductions in specific cytokines (e.g., IL-1α, IL-12p40) and microglial reactivity. In contrast, short-term, escalating morphine exposure acted as a secondary stressor revealing an allostatic shift in CNS baseline inflammatory responsiveness from sustained Tat exposure.
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Affiliation(s)
- Douglas J Hermes
- Department of Psychology & Neuroscience, University of North Carolina, Chapel Hill, NC, USA
| | - Ian R Jacobs
- Department of Psychology & Neuroscience, University of North Carolina, Chapel Hill, NC, USA
| | - Megan C Key
- Department of Psychology & Neuroscience, University of North Carolina, Chapel Hill, NC, USA
| | - Alexis F League
- Department of Psychology & Neuroscience, University of North Carolina, Chapel Hill, NC, USA
| | | | - Changqing Xu
- Department of Psychology & Neuroscience, University of North Carolina, Chapel Hill, NC, USA
| | - Virginia D McLane
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - Sara R Nass
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - Wei Jiang
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
- Division of Infectious Diseases, Department of Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Rick B Meeker
- Department of Neurology, University of North Carolina, Chapel Hill, NC, USA
| | | | - Aron H Lichtman
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - Zibo Li
- Department of Radiology, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Zhanhong Wu
- Department of Radiology, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Hong Yuan
- Department of Radiology, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Pamela E Knapp
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, USA
- Department of Anatomy & Neurobiology, Virginia Commonwealth University, Richmond, VA, USA
| | - Kurt F Hauser
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, USA
- Department of Anatomy & Neurobiology, Virginia Commonwealth University, Richmond, VA, USA
| | - Sylvia Fitting
- Department of Psychology & Neuroscience, University of North Carolina, Chapel Hill, NC, USA.
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