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Dion-Albert L, Bandeira Binder L, Daigle B, Hong-Minh A, Lebel M, Menard C. Sex differences in the blood-brain barrier: Implications for mental health. Front Neuroendocrinol 2022; 65:100989. [PMID: 35271863 DOI: 10.1016/j.yfrne.2022.100989] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/07/2022] [Accepted: 02/19/2022] [Indexed: 12/13/2022]
Abstract
Prevalence of mental disorders, including major depressive disorder (MDD), bipolar disorder (BD) and schizophrenia (SZ) are increasing at alarming rates in our societies. Growing evidence points toward major sex differences in these conditions, and high rates of treatment resistance support the need to consider novel biological mechanisms outside of neuronal function to gain mechanistic insights that could lead to innovative therapies. Blood-brain barrier alterations have been reported in MDD, BD and SZ. Here, we provide an overview of sex-specific immune, endocrine, vascular and transcriptional-mediated changes that could affect neurovascular integrity and possibly contribute to the pathogenesis of mental disorders. We also identify pitfalls in current literature and highlight promising vascular biomarkers. Better understanding of how these adaptations can contribute to mental health status is essential not only in the context of MDD, BD and SZ but also cardiovascular diseases and stroke which are associated with higher prevalence of these conditions.
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Affiliation(s)
- Laurence Dion-Albert
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada
| | - Luisa Bandeira Binder
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada
| | - Beatrice Daigle
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada
| | - Amandine Hong-Minh
- Smurfit Institute of Genetics, Trinity College Dublin, Lincoln Place Gate, Dublin 2, Ireland
| | - Manon Lebel
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada
| | - Caroline Menard
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada.
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Kitanaka N, Hall FS, Uhl GR, Kitanaka J. Lithium Pharmacology and a Potential Role of Lithium on Methamphetamine Abuse and Dependence. Curr Drug Res Rev 2020; 11:85-91. [PMID: 31875781 DOI: 10.2174/2589977511666190620141824] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/18/2019] [Accepted: 05/10/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND The effectiveness of lithium salts in neuropsychiatric disorders such as bipolar disorder, Alzheimer's disease, and treatment-resistant depression has been documented in an extensive scientific literature. Lithium inhibits inositol monophosphatase, inositol polyphosphate 1- phosphatase, and glycogen synthase kinase-3 and decreases expression level of tryptophan hydroxylase 2, conceivably underlying the mood stabilizing effects of lithium, as well as procognitive and neuroprotective effects. However, the exact molecular mechanisms of action of lithium on mood stabilizing and pro-cognitive effects in humans are still largely unknown. OBJECTIVE On the basis of the known aspects of lithium pharmacology, this review will discuss the possible mechanisms underlying the therapeutic effects of lithium on positive symptoms of methamphetamine abuse and dependence. CONCLUSION It is possible that lithium treatment reduces the amount of newly synthesized phosphatidylinositol, potentially preventing or reversing neuroadaptations contributing to behavioral sensitization induced by methamphetamine. In addition, it is suggested that exposure to repeated doses of methamphetamine induces hyperactivation of glycogen synthase kinase-3β in the nucleus accumbens and in dorsal hippocampus, resulting in a long-term alterations in synaptic plasticity underlying behavioral sensitization as well as other behavioral deficits in memory-related behavior. Therefore it is clear that glycogen synthase kinase-3β inhibitors can be considered as a potential candidate for the treatment of methamphetamine abuse and dependence.
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Affiliation(s)
- Nobue Kitanaka
- Department of Pharmacology, Hyogo College of Medicine, Hyogo 663-8501, Japan
| | - Frank Scott Hall
- Department of Pharmacology and Experimental Therapeutics, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, Ohio 43614, United States
| | - George Richard Uhl
- Neurology and Research Services, New Mexico VA Healthcare System, Albuquerque, New Mexico 87108, United States.,Departments of Neurology, Neuroscience, Molecular Genetics and Microbiology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Junichi Kitanaka
- Department of Pharmacology, Hyogo College of Medicine, Hyogo 663-8501, Japan
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m6A RNA Methylation Controls Neural Development and Is Involved in Human Diseases. Mol Neurobiol 2018; 56:1596-1606. [DOI: 10.1007/s12035-018-1138-1] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/18/2018] [Indexed: 12/31/2022]
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McCoy MT, Jayanthi S, Wulu JA, Beauvais G, Ladenheim B, Martin TA, Krasnova IN, Hodges AB, Cadet JL. Chronic methamphetamine exposure suppresses the striatal expression of members of multiple families of immediate early genes (IEGs) in the rat: normalization by an acute methamphetamine injection. Psychopharmacology (Berl) 2011; 215:353-65. [PMID: 21229349 PMCID: PMC3803141 DOI: 10.1007/s00213-010-2146-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 12/09/2010] [Indexed: 11/28/2022]
Abstract
RATIONALE Repeated injections of cocaine cause blunted responses to acute cocaine challenge-induced increases in the expression of immediate early genes (IEGs). OBJECTIVES The aim of this study was to test if chronic methamphetamine (METH) exposure might cause similar blunting of acute METH-induced increases in IEG expression. RESULTS Repeated saline or METH injections were given to rats over 14 days. After 1 day of withdrawal, they received a single injection of saline or METH (5 mg/kg). Acute injection of METH increased c-fos, fosB, fra2, junB, Egr1-3, Nr4a1 (Nur77), and Nr4a3 (Nor-1) mRNA levels in the striatum of saline-pretreated rats. Chronic METH treatment alone reduced the expression of AP1, Erg1-3, and Nr4a1 transcription factors below control levels. Acute METH challenge normalized these values in METH-pretreated rats. Unexpectedly, acute METH challenge to METH-pretreated animals caused further decreases in Nr4a2 (Nurr1) mRNA levels. In contrast, the METH challenge caused significant but blunted increases in Nr4a3 and Arc expression in METH-pretreated rats. There were also chronic METH-associated decreases in the expression of cAMP responsive element binding protein (CREB) which modulates IEG expression via activation of the cAMP/PKA/CREB signal transduction pathway. Chronic METH exposure also caused significant decreases in preprotachykinin, but not in prodynorphin, mRNA levels. CONCLUSIONS These results support the accumulated evidence that chronic administration of psychostimulants is associated with blunting of their acute stimulatory effects on IEG expression. The METH-induced renormalization of the expression of several IEGs in rats chronically exposed to METH hints to a potential molecular explanation for the recurrent self-administration of the drug by human addicts.
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Affiliation(s)
- Michael T. McCoy
- Molecular Neuropsychiatry Research Branch, DHHS/NIH/NIDA Intramural Research Program, Morgan State University, Baltimore, MD, USA
| | - Subramaniam Jayanthi
- Molecular Neuropsychiatry Research Branch, DHHS/NIH/NIDA Intramural Research Program, Morgan State University, Baltimore, MD, USA
| | - Jacqueline A. Wulu
- Molecular Neuropsychiatry Research Branch, DHHS/NIH/NIDA Intramural Research Program, Morgan State University, Baltimore, MD, USA
| | - Genevieve Beauvais
- Molecular Neuropsychiatry Research Branch, DHHS/NIH/NIDA Intramural Research Program, Morgan State University, Baltimore, MD, USA
| | - Bruce Ladenheim
- Molecular Neuropsychiatry Research Branch, DHHS/NIH/NIDA Intramural Research Program, Morgan State University, Baltimore, MD, USA
| | - Tracey A. Martin
- Molecular Neuropsychiatry Research Branch, DHHS/NIH/NIDA Intramural Research Program, Morgan State University, Baltimore, MD, USA
| | - Irina N. Krasnova
- Molecular Neuropsychiatry Research Branch, DHHS/NIH/NIDA Intramural Research Program, Morgan State University, Baltimore, MD, USA
| | - Amber B. Hodges
- Molecular Neuropsychiatry Research Branch, DHHS/NIH/NIDA Intramural Research Program, Morgan State University, Baltimore, MD, USA,Department of Psychology, Morgan State University, Baltimore, MD, USA
| | - Jean Lud Cadet
- Molecular Neuropsychiatry Research Branch, DHHS/NIH/NIDA Intramural Research Program, Morgan State University, Baltimore, MD, USA
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Lithium and genetic inhibition of GSK3beta enhance the effect of methamphetamine on circadian rhythms in the mouse. Behav Pharmacol 2009; 20:174-83. [PMID: 19339873 DOI: 10.1097/fbp.0b013e32832a8f43] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Lithium, a drug commonly used to treat mood disorders, and the psychostimulant methamphetamine are both capable of altering circadian rhythmicity. Although the actions of lithium on the circadian system are thought to occur through inhibition of glycogen synthase kinase-3beta (GSK3beta), the mechanism by which methamphetamine alters circadian rhythms is unknown. We tested the effects of concurrent methamphetamine and lithium treatment on the circadian wheel-running behavior of mice. Methamphetamine alone lengthened both the active duration and the free-running period of locomotor activity in animals housed in constant conditions. Administering lithium enhanced the period-lengthening effects of methamphetamine in animals housed in constant darkness. This effect was even more pronounced when animals were housed in constant light. Lithium increased both methamphetamine intake and serum levels of methamphetamine, possibly contributing to the effects on circadian behavior. We also tested the effect of methamphetamine in mutant mice possessing only one allele for Gsk3beta. These animals, when treated with methamphetamine, responded like wild-type mice treated with a combination of methamphetamine and lithium, displaying long, free-running rhythms. These data, together with many others in the literature, point to a complicated interaction between the circadian system and the development and possible treatment of psychopathologies such as bipolar disorder and drug addiction.
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Moutsimilli L, Farley S, El Khoury MA, Chamot C, Sibarita JB, Racine V, El Mestikawy S, Mathieu F, Dumas S, Giros B, Tzavara ET. Antipsychotics increase vesicular glutamate transporter 2 (VGLUT2) expression in thalamolimbic pathways. Neuropharmacology 2008; 54:497-508. [DOI: 10.1016/j.neuropharm.2007.10.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Revised: 10/13/2007] [Accepted: 10/25/2007] [Indexed: 10/22/2022]
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Gould TD, Einat H, O'Donnell KC, Picchini AM, Schloesser RJ, Manji HK. Beta-catenin overexpression in the mouse brain phenocopies lithium-sensitive behaviors. Neuropsychopharmacology 2007; 32:2173-83. [PMID: 17299510 DOI: 10.1038/sj.npp.1301338] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Lithium inhibits glycogen synthase kinase-3 (GSK-3) at therapeutic concentrations; however, it is unclear if this inhibition and its downstream effects on specific signaling pathways are relevant to the treatment of bipolar disorder and depression. One of the targets of GSK-3 is the transcription factor beta-catenin. Normally active GSK-3 phosphorylates beta-catenin, leading to its degradation. Inhibition of GSK-3 therefore increases beta-catenin. We have utilized transgenic mice to investigate the behavioral consequences of CNS beta-catenin overexpression. Transgenic mice overexpressing beta-catenin demonstrated behavioral changes similar to those observed following the administration of lithium, including decreased immobility time in the forced swim test (FST). Further, we show that although acute administration of lithium and overexpression of the beta-catenin transgene inhibits d-amphetamine-induced hyperlocomotion, neither lithium nor the beta-catenin transgene prevents d-amphetamine-induced sensitization, as measured by locomotor activity. Both lithium-treated and beta-catenin mice had an elevated response to d-amphetamine following multiple administrations of the stimulant, though the difference in absolute locomotion was maintained throughout the sensitization time-course. Neither acute lithium nor beta-catenin overexpression had an effect on d-amphetamine-induced stereotyped behavior. The results of this study, in which beta-catenin transgenic mice exhibited behaviors identical to those observed in lithium-treated mice, are consistent with the hypothesis that the behavioral effects of lithium in these models are mediated through its direct inhibition of GSK-3 and the consequent increase in beta-catenin. By associating the behavioral effects of lithium with beta-catenin levels, these data suggest that increasing beta-catenin might be a novel therapeutic strategy for mood disorders.
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Affiliation(s)
- Todd D Gould
- Laboratory of Molecular Pathophysiology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-3711, USA
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O'Donnell KC, Gould TD. The behavioral actions of lithium in rodent models: leads to develop novel therapeutics. Neurosci Biobehav Rev 2007; 31:932-62. [PMID: 17532044 PMCID: PMC2150568 DOI: 10.1016/j.neubiorev.2007.04.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Revised: 03/27/2007] [Indexed: 12/13/2022]
Abstract
For nearly as long as lithium has been in clinical use for the treatment of bipolar disorder, depression, and other conditions, investigators have attempted to characterize its effects on behaviors in rodents. Lithium consistently decreases exploratory activity, rearing, aggression, and amphetamine-induced hyperlocomotion; and it increases the sensitivity to pilocarpine-induced seizures, decreases immobility time in the forced swim test, and attenuates reserpine-induced hypolocomotion. Lithium also predictably induces conditioned taste aversion and alterations in circadian rhythms. The modulation of stereotypy, sensitization, and reward behavior are less consistent actions of the drug. These behavioral models may be relevant to human symptoms and to clinical endophenotypes. It is likely that the actions of lithium in a subset of these animal models are related to the therapeutic efficacy, as well the side effects, of the drug. We conclude with a brief discussion of various molecular mechanisms by which these lithium-sensitive behaviors may be mediated, and comment on the ways in which rat and mouse models can be used more effectively in the future to address persistent questions about the therapeutically relevant molecular actions of lithium.
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Affiliation(s)
- Kelley C O'Donnell
- The Laboratory of Molecular Pathophysiology, Mood and Anxiety Disorders Program, National Institute of Mental Health, NIH, HHS, Bldg 35, Rm 1C-912, 35 Convent Drive, Bethesda, MD 20892 3711, USA
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Kato T, Kubota M, Kasahara T. Animal models of bipolar disorder. Neurosci Biobehav Rev 2007; 31:832-42. [PMID: 17466374 DOI: 10.1016/j.neubiorev.2007.03.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Revised: 03/06/2007] [Accepted: 03/13/2007] [Indexed: 12/31/2022]
Abstract
Animal models of human diseases should meet three sets of criteria: construct validity, face validity, and predictive validity. To date, several putative animal models of bipolar disorder have been reported. They are classified into various categories: pharmacological models, nutritional models, environmental models, and genetic models. None of them, however, totally fulfills the three validity criteria, and thus may not be useful for drug development. Mounting evidence suggests that mitochondrial dysfunction has a role in bipolar disorder. To test whether accumulation of mtDNA deletions in the brain can cause bipolar disorder, we generated transgenic mice with neuron-specific expression of mutant Polg (D181A). These mice showed altered diurnal activity rhythm and periodic activity change associated with the estrous cycle. These phenotypes were worsened by administration of a tricyclic antidepressant, but improved after lithium treatment. This mouse model of bipolar disorder potentially fulfills the three validity criteria, and therefore might be used for future drug development studies.
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Affiliation(s)
- Tadafumi Kato
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Hirosawa 2-1, Wako, Saitama 351-0198, Japan.
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Moutsimilli L, Farley S, Dumas S, El Mestikawy S, Giros B, Tzavara ET. Selective cortical VGLUT1 increase as a marker for antidepressant activity. Neuropharmacology 2005; 49:890-900. [PMID: 16111724 DOI: 10.1016/j.neuropharm.2005.06.017] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Revised: 06/22/2005] [Accepted: 06/27/2005] [Indexed: 11/16/2022]
Abstract
The two recently characterized vesicular glutamate transporters (VGLUT) presynaptically mark and differentiate two distinct excitatory neuronal populations and thus define a cortical and a subcortical glutamatergic system (VGLUT1 and VGLUT2 positive, respectively). These two systems might be differentially implicated in brain neuropathology. Still, little is known on the modalities of VGLUT1 and VGLUT2 regulations in response to pharmacological or physiological stimuli. Given the importance of cortical neuronal activity in psychosis we investigated VGLUT1 mRNA and protein expression in response to chronic treatment with commonly prescribed psychotropic medications. We show that agents with antidepressant activity, namely the antidepressants fluoxetine and desipramine, the atypical antipsychotic clozapine, and the mood stabilizer lithium increased VGLUT1 mRNA expression in neurons of the cerebral cortex and the hippocampus and in concert enhanced VGLUT1 protein expression in their projection fields. In contrast the typical antipsychotic haloperidol, the cognitive enhancers memantine and tacrine, and the anxiolytic diazepam were without effect. We suggest that VGLUT1 could be a useful marker for antidepressant activity. Furthermore, adaptive changes in VGLUT1 positive neurons could constitute a common functional endpoint for structurally unrelated antidepressants, representing promising antidepressant targets in tracking specificity, mechanism, and onset at action.
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Affiliation(s)
- Larissa Moutsimilli
- INSERM U513, Neurobiologie et Psychiatrie, 8, rue du Général Sarrail, Créteil 94010 cedex, France
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Okabe C, Murphy NP. Short-term effects of the nociceptin receptor antagonist Compound B on the development of methamphetamine sensitization in mice: a behavioral and c-fos expression mapping study. Brain Res 2004; 1017:1-12. [PMID: 15261093 DOI: 10.1016/j.brainres.2004.04.076] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2004] [Indexed: 11/19/2022]
Abstract
The nociceptin antagonist Compound B (CompB) stimulates mesolimbic dopamine release and induces a conditioned place preference but has little effect on locomotion. As behavioral sensitization often occurs as an epiphenomenon to mesolimbic activation and reward, we studied the effect of CompB on behavioral sensitization to methamphetamine. Locomotor responses of C57BL6 mice to repeated methamphetamine (2 mg/kg s.c.) administration alone or immediately following CompB (10 mg/kg s.c.) were recorded for 3 alternating days. Six days later, methamphetamine (1 mg/kg s.c.) was administered and locomotor activity monitored again before determining neural activity by analysis of c-fos expression. Methamphetamine treatment induced a progressive locomotor (behavioral) sensitization, with CompB pretreatment enhancing the locomotor response to methamphetamine during the early stages only. Previous CompB administration little affected methamphetamine-sensitized or acute methamphetamine-induced locomotion on the challenge day. Analysis of c-fos expression supported these results as of the 36 neuroanatomical regions quantified; very few showed CompB-dependent responses. However, numerous regions differentially responsive to either acute (e.g. ventromedial, ventrolateral and central caudate putamen), chronic (e.g. central amygdala, lateral habenula, dorsomedial caudate putamen) or sensitized (e.g. medial nucleus accumbens core, central amygdala, lateral habenula) methamphetamine treatment were identified, thereby providing a comprehensive map of the short and long-term effects of methamphetamine on mouse brain activity per se. Thus, despite its mesolimbic activating and rewarding properties, CompB has little long-term influence on neural activity, suggesting CompB is able to induce short-term increases in hedonic state in the absence of locomotion or major long-term effects.
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Affiliation(s)
- Chinami Okabe
- Neuronal Circuit Mechanisms Research Group, RIKEN Brain Science Institute, 2-1 Hirosawa, Wakoshi, Saitama, 351-0198, Japan
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Chen G, Masana MI, Manji HK. Lithium regulates PKC-mediated intracellular cross-talk and gene expression in the CNS in vivo. Bipolar Disord 2000; 2:217-36. [PMID: 11249800 DOI: 10.1034/j.1399-5618.2000.20303.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
It has become increasingly appreciated that the long-term treatment of complex neuropsychiatric disorders like bipolar disorder (BD) involves the strategic regulation of signaling pathways and gene expression in critical neuronal circuits. Accumulating evidence from our laboratories and others has identified the family of protein kinase C (PKC) isozymes as a shared target in the brain for the long-term action of both lithium and valproate (VPA) in the treatment of BD. In rats chronically treated with lithium at therapeutic levels, there is a reduction in the levels of frontal cortical and hippocampal membrane-associated PKC alpha and PKC epsilon. Using in vivO microdialysis, we have investigated the effects of chronic lithium on the intracellular cross-talk between PKC and the cyclic AMP (cAMP) generating system in vivo. We have found that activation of PKC produces an increase in dialysate cAMP levels in both prefrontal cortex and hippocampus, effects which are attenuated by chronic lithium administration. Lithium also regulates the activity of another major signaling pathway the c-Jun N-terminal kinase pathway--in a PKC-dependent manner. Both Li and VPA, at therapeutically relevant concentrations, increase the DNA binding of activator protein 1 (AP-1) family of transcription factors in cultured cells in vitro, and in rat brain ex vivo. Furthermore, both agents increase the expression of an AP-1 driven reporter gene, as well as the expression of several endogenous genes known to be regulated by AP-1. Together, these results suggest that the PKC signaling pathway and PKC-mediated gene expression may be important mediators of lithium's long-term therapeutic effects in a disorder as complex as BD.
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Affiliation(s)
- G Chen
- Department of Psychiatry and Behavioral Neurosciences, WSU School of Medicine, Detroit, MI 48201, USA.
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Abstract
The therapeutic efficacy of lithium in the treatment of mood disorders is delayed and only observed after chronic administration, a temporal profile that suggests alterations at the genomic level. Lithium has been demonstrated to modulate AP-1 DNA binding activity as well as the expression of genes regulated by AP-1, but the mechanisms underlying these effects have not been fully elucidated. In the present study, we found that the lithium-induced increases in AP-1 DNA binding activity were accompanied by increases in p-cJun and cJun levels in SH-SY5Y cells. Lithium also increased cJun-mediated reporter gene expression in a dose-dependent manner, with significant effects observed at therapeutically relevant concentrations. Lithium's effects on cJun-mediated reporter gene expression in SH-SY5Y cells were more pronounced in the absence of myo-inositol and were blocked by protein kinase C (PKC) inhibitors and by cotransfection with a PKCalpha dominant-negative mutant. Chronic in vivo lithium administration increased AP-1 DNA binding activity in frontal cortex and hippocampus and also increased the levels of the phosphorylated, active forms of c-Jun NH2-terminal kinases (JNKs) in both brain regions. These results demonstrate that lithium activates the JNK signaling pathway in rat brain during chronic in vivo administration and in human cells of neuronal origin in vitro; in view of the role of JNKs in regulating various aspects of neuronal function and their well-documented role in regulating gene expression, these effects may play a major role in lithium's long-term therapeutic effects.
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Affiliation(s)
- P Yuan
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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