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Wang J, Long R, Han Y. The role of exosomes in the tumour microenvironment on macrophage polarisation. Biochim Biophys Acta Rev Cancer 2022; 1877:188811. [DOI: 10.1016/j.bbcan.2022.188811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/15/2022] [Accepted: 09/28/2022] [Indexed: 12/14/2022]
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Albert PR, Vahid-Ansari F. The 5-HT1A receptor: Signaling to behavior. Biochimie 2019; 161:34-45. [DOI: 10.1016/j.biochi.2018.10.015] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 10/23/2018] [Indexed: 02/06/2023]
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Wang XL, Gao J, Wang XY, Mu XF, Wei S, Xue L, Qiao MQ. Treatment with Shuyu capsule increases 5-HT1AR level and activation of cAMP-PKA-CREB pathway in hippocampal neurons treated with serum from a rat model of depression. Mol Med Rep 2017; 17:3575-3582. [PMID: 29286104 PMCID: PMC5802157 DOI: 10.3892/mmr.2017.8339] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 11/10/2017] [Indexed: 11/13/2022] Open
Abstract
Depressive disorder (DD) is one of the typical affective disorders with a high morbidity, high suicide rate and high recurrence rate. Dysfunction of the 5-hydroxytryptamine 1A receptor (5-HT1AR) in the brain may serve an important role in the pathogenesis of DD. Currently, selective serotonin reuptake inhibitors are the first line antidepressants with 60–70% efficacy and severe adverse effects. Previous studies have demonstrated that Chinese herbal medicines, including the Shuyu capsule (SYC), are effective antidepressants with few side effects. However, the mechanism remains unclear. In the present study, the effects of the SYC on the 5-HT1AR level and the activation of adenylyl cyclase-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA)-cAMP response element-binding (CREB) signaling pathway that 5-HT1AR mediates in the cells of hippocampal neurons were investigated in vitro. The SYC demonstrated an antidepressant effect similar to that of fluoxetine in a rat depression model. Treatment of hippocampal neurons with the serum of depressive rats resulted in a decrease in the 5-HT1AR protein level and the activation of the cAMP-PKA-CREB signaling pathway in hippocampal neurons. Exposure to the serum of rats that received chronic mild stress plus SYC treatment led to no alterations in the 5-HT1AR level or the activation of the cAMP-PKA-CREB signaling pathway compared with those of cells exposed to normal rat serum. This effect is similar to the effects of 5-HT1AR antagonist WAY-100635. In addition, the 5-HT1A agonist 8-hydroxy-(dipropylamino) tetralin did not antagonize the effects of the SYC. Furthermore, the SYC exhibited an increased effect compared with fluoxetine on 5-HT1AR levels and CREB activation. The present study suggested that the SYC functions by increasing 5-HT1AR protein levels and the activation of the 5-HT1AR-mediated cAMP-PKA-CREB signaling pathway in hippocampal neurons.
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Affiliation(s)
- Xiao-Long Wang
- School of Pharmacy, School of Basic Medical Sciences, Shandong University of Traditional Chinese Medicine, Jinan, Shangdong 250355, P.R. China
| | - Jie Gao
- Institute of Traditional Chinese Medicine Basic Theory, School of Basic Medical Sciences, Shandong University of Traditional Chinese Medicine, Jinan, Shangdong 250355, P.R. China
| | - Xiao-Yu Wang
- Institute of Traditional Chinese Medicine Basic Theory, School of Basic Medical Sciences, Shandong University of Traditional Chinese Medicine, Jinan, Shangdong 250355, P.R. China
| | - Xiao-Fei Mu
- School of Pharmacy, School of Basic Medical Sciences, Shandong University of Traditional Chinese Medicine, Jinan, Shangdong 250355, P.R. China
| | - Sheng Wei
- Laboratory Animal Center, Shandong University of Traditional Chinese Medicine, Jinan, Shangdong 250355, P.R. China
| | - Ling Xue
- School of Pharmacy, School of Basic Medical Sciences, Shandong University of Traditional Chinese Medicine, Jinan, Shangdong 250355, P.R. China
| | - Ming-Qi Qiao
- Institute of Traditional Chinese Medicine Basic Theory, School of Basic Medical Sciences, Shandong University of Traditional Chinese Medicine, Jinan, Shangdong 250355, P.R. China
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Meunier CNJ, Chameau P, Fossier PM. Modulation of Synaptic Plasticity in the Cortex Needs to Understand All the Players. Front Synaptic Neurosci 2017; 9:2. [PMID: 28203201 PMCID: PMC5285384 DOI: 10.3389/fnsyn.2017.00002] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/13/2017] [Indexed: 12/19/2022] Open
Abstract
The prefrontal cortex (PFC) is involved in cognitive tasks such as working memory, decision making, risk assessment and regulation of attention. These functions performed by the PFC are supposed to rely on rhythmic electrical activity generated by neuronal network oscillations determined by a precise balance between excitation and inhibition balance (E/I balance) resulting from the coordinated activities of recurrent excitation and feedback and feedforward inhibition. Functional alterations in PFC functions have been associated with cognitive deficits in several pathologies such as major depression, anxiety and schizophrenia. These pathological situations are correlated with alterations of different neurotransmitter systems (i.e., serotonin (5-HT), dopamine (DA), acetylcholine…) that result in alterations of the E/I balance. The aim of this review article is to cover the basic aspects of the regulation of the E/I balance as well as to highlight the importance of the complementarity role of several neurotransmitters in the modulation of the plasticity of excitatory and inhibitory synapses. We illustrate our purpose by recent findings that demonstrate that 5-HT and DA cooperate to regulate the plasticity of excitatory and inhibitory synapses targeting layer 5 pyramidal neurons (L5PyNs) of the PFC and to fine tune the E/I balance. Using a method based on the decomposition of the synaptic conductance into its excitatory and inhibitory components, we show that concomitant activation of D1-like receptors (D1Rs) and 5-HT1ARs, through a modulation of NMDA receptors, favors long term potentiation (LTP) of both excitation and inhibition and consequently does not modify the E/I balance. We also demonstrate that activation of D2-receptors requires functional 5-HT1ARs to shift the E-I balance towards more inhibition and to favor long term depression (LTD) of excitatory synapses through the activation of glycogen synthase kinase 3β (GSK3β). This cooperation between different neurotransmitters is particularly relevant in view of pathological situations in which alterations of one neurotransmitter system will also have consequences on the regulation of synaptic efficacy by other neurotransmitters. This opens up new perspectives in the development of therapeutic strategies for the pharmacological treatment of neuronal disorders.
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Affiliation(s)
- Claire N J Meunier
- Institut de Neurosciences Paris-Saclay (NeuroPSI), UMR 91197 CNRS-Université Paris-Saclay Paris, France
| | - Pascal Chameau
- Swammerdam Institute for Life Sciences, Center for NeuroScience, University of Amsterdam Amsterdam, Netherlands
| | - Philippe M Fossier
- Institut de Neurosciences Paris-Saclay (NeuroPSI), UMR 91197 CNRS-Université Paris-Saclay Paris, France
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Lack of GSK3β activation and modulation of synaptic plasticity by dopamine in 5-HT1A-receptor KO mice. Neuropharmacology 2016; 113:124-136. [PMID: 27678414 DOI: 10.1016/j.neuropharm.2016.09.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 09/13/2016] [Accepted: 09/23/2016] [Indexed: 12/31/2022]
Abstract
Psychiatric disorders are associated with excitation-inhibition (E-I) balance impairment in the prefrontal cortex. However, how the E-I balance is regulated is poorly known. The E-I balance of neuronal networks is linked to the action of numerous neuromodulators such as dopamine and 5-HT. We investigated the role of D2-receptors in tuning the E-I balance in a mouse model of anxiety, the 5-HT1A-receptor KO mice. We focused on synaptic plasticity of excitation and inhibition on layer 5 pyramidal neurons. We show that D2-receptor activation decreases the excitation and favors HFS-induced LTD of excitatory synapses via the activation of GSK3β. This effect is absent in 5-HT1A-receptor KO mice. Our data show that the fine control of excitatory transmission by GSK3β requires recruitment of D2-receptors and depends on the presence of 5-HT1A-receptors. In psychiatric disorders in which the number of 5-HT1A-receptors decreased, therapies should reconsider how serotonin and dopamine receptors interact and control neuronal network activity.
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Piromelatine ameliorates memory deficits associated with chronic mild stress-induced anhedonia in rats. Psychopharmacology (Berl) 2016; 233:2229-39. [PMID: 27007604 DOI: 10.1007/s00213-016-4272-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 03/08/2016] [Indexed: 12/15/2022]
Abstract
RATIONALE Previous studies have demonstrated that piromelatine (a melatonin and serotonin 5-HT1A and 5-HT1D agonist) exerts an antidepressant activity in rodent models of acute stress and improves cognitive impairments in a rat model of Alzheimer's disease (AD). However, the role of piromelatine in chronic stress-induced memory dysfunction remains unclear. OBJECTIVE The aim of this study was to determine whether piromelatine ameliorates chronic mild stress (CMS)-induced memory deficits and explore the underlying mechanisms. METHODS Rats were exposed randomly to chronic mild stressors for 7 weeks to induce anhedonia (reflected by a significant decrease in sucrose intake), which was used to select rats vulnerable (CMS-anhedonic, CMSA) or resistant (CMS-resistant, CMSR) to stress. Piromelatine (50 mg/kg) was administered daily during the last 2 weeks of CMS. The tail suspension and forced swimming tests were adopted to further characterize vulnerable and resilient rats. The Y-maze and novel object recognition (NOR) tests were used to evaluate memory performance. Brain-derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), phosphorylated CREB (pCREB), and cytogenesis were measured in the hippocampus. RESULTS We found that only CMSA rats displayed significant increases in immobility time in the tail suspension and forced swimming tests; memory deficits in the Y-maze and NOR tests; significant decreases in hippocampal BDNF, CREB, and pCREB expression; and cytogenesis. All these anhedonia-associated effects were reversed by piromelatine. CONCLUSIONS Piromelatine ameliorates memory deficits associated with CMS-induced anhedonia in rats and this effect may be mediated by restoring hippocampal BDNF, CREB, and cytogenesis deficits.
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Daniele S, Zappelli E, Martini C. Trazodone regulates neurotrophic/growth factors, mitogen-activated protein kinases and lactate release in human primary astrocytes. J Neuroinflammation 2015; 12:225. [PMID: 26627476 PMCID: PMC4666178 DOI: 10.1186/s12974-015-0446-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 11/25/2015] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND In the central nervous system, glial cells provide metabolic and trophic support to neurons and respond to protracted stress and insults by up-regulating inflammatory processes. Reactive astrocytes and microglia are associated with the pathophysiology of neuronal injury, neurodegenerative diseases and major depression, in both animal models and human brains. Several studies have reported clear anti-inflammatory effects of anti-depressant treatment on astrocytes, especially in models of neurological disorders. Trazodone (TDZ) is a triazolopyridine derivative that is structurally unrelated to other major classes of antidepressants. Although the molecular mechanisms of TDZ in neurons have been investigated, it is unclear whether astrocytes are also a TDZ target. METHODS The effects of TDZ on human astrocytes were investigated in physiological conditions and following inflammatory insult with lipopolysaccharide (LPS) and tumour necrosis factor-α (TNF-α). Astrocytes were assessed for their responses to pro-inflammatory mediators and cytokines, and the receptors and signalling pathways involved in TDZ-mediated effects were evaluated. RESULTS TDZ had no effect on cell proliferation, but it decreased pro-inflammatory mediator release and modulated trophic and transcription factor mRNA expression. Following TDZ treatment, the AKT pathway was activated, whereas extracellular signal-regulated kinase and c-Jun NH2-terminal kinase were inhibited. Most importantly, a 72-h TDZ pre-treatment before inflammatory insult completely reversed the anti-proliferative effects induced by LPS-TNF-α. The expression or the activity of inflammatory mediators, including interleukin-6, c-Jun NH2-terminal kinase and nuclear factor κB, were also reduced. Furthermore, TDZ affected astrocyte metabolic support to neurons by counteracting the inflammation-mediated lactate decrease. Finally, TDZ protected neuronal-like cells against neurotoxicity mediated by activated astrocytes. These effects mainly involved an activation of 5-HT1A and an antagonism at 5-HT2A/C serotonin receptors. Fluoxetine, used in parallel, showed similar final effects nevertheless it activates different receptors/intracellular pathways. CONCLUSIONS Altogether, our results demonstrated that TDZ directly acts on astrocytes by regulating intracellular signalling pathways and increasing specific astrocyte-derived neurotrophic factor expression and lactate release. TDZ may contribute to neuronal support by normalizing trophic and metabolic support during neuroinflammation, which is associated with neurological diseases, including major depression.
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Affiliation(s)
- Simona Daniele
- Department of Pharmacy, University of Pisa, Via Bonanno Pisano, 6, Pisa, 56126, PI, Italy.
| | - Elisa Zappelli
- Department of Pharmacy, University of Pisa, Via Bonanno Pisano, 6, Pisa, 56126, PI, Italy.
| | - Claudia Martini
- Department of Pharmacy, University of Pisa, Via Bonanno Pisano, 6, Pisa, 56126, PI, Italy.
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Mao Z, Song Z, Li G, Lv W, Zhao X, Li B, Feng X, Chen Y. 8-hydroxy-2-(di-n-propylamino)tetralin intervenes with neural cell apoptosis following diffuse axonal injury. Neural Regen Res 2014; 8:133-42. [PMID: 25206483 PMCID: PMC4107509 DOI: 10.3969/j.issn.1673-5374.2013.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 12/16/2012] [Indexed: 11/30/2022] Open
Abstract
Previous studies have reported a neuroprotective effect of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) against traumatic brain injury. In accordance with the Marmarou method, rat models of diffuse axonal injury were established. 8-OH-DPAT was intraperitoneally injected into model rats. 8-OH-DPAT treated rats maintained at constant temperature served as normal temperature controls. TUNEL results revealed that neural cell swelling, brain tissue necrosis and cell apoptosis occurred around the injured tissue. Moreover, the number of Bax-, Bcl-2- and caspase-3-positive cells increased at 6 hours after diffuse axonal injury, and peaked at 24 hours. However, brain injury was attenuated, the number of apoptotic cells reduced, Bax and caspase-3 expression decreased, and Bcl-2 expression increased at 6, 12, 24, 72 and 168 hours after diffuse axonal injury in normal temperature control and in 8-OH-DPAT-intervention rats. The difference was most significant at 24 hours. All indices in 8-OH-DPAT-intervention rats were better than those in the constant temperature group. These results suggest that 8-OH-DPAT inhibits Bax and caspase-3 expression, increases Bcl-2 expression, and reduces neural cell apoptosis, resulting in neuroprotection against diffuse axonal injury. This effect is associated with a decrease in brain temperature.
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Affiliation(s)
- Zhenli Mao
- Department of Neurosurgery, General Hospital of Shenyang Military Region, Shenyang 110016, Liaoning Province, China ; Postgraduate School, Liaoning Medical University, Jinzhou 121001, Liaoning Province, China
| | - Zhenquan Song
- Department of Neurosurgery, General Hospital of Shenyang Military Region, Shenyang 110016, Liaoning Province, China
| | - Gang Li
- Jilin Brain Hospital, Siping 136000, Jilin Province, China
| | - Wei Lv
- Department of Neurosurgery, General Hospital of Shenyang Military Region, Shenyang 110016, Liaoning Province, China ; Postgraduate School, Liaoning Medical University, Jinzhou 121001, Liaoning Province, China
| | - Xu Zhao
- Department of Neurosurgery, General Hospital of Shenyang Military Region, Shenyang 110016, Liaoning Province, China ; Postgraduate School, Liaoning Medical University, Jinzhou 121001, Liaoning Province, China
| | - Bin Li
- Department of Neurosurgery, General Hospital of Shenyang Military Region, Shenyang 110016, Liaoning Province, China ; Postgraduate School, Liaoning Medical University, Jinzhou 121001, Liaoning Province, China
| | - Xinli Feng
- Department of Neurosurgery, General Hospital of Shenyang Military Region, Shenyang 110016, Liaoning Province, China
| | - Youli Chen
- Department of Neurosurgery, General Hospital of Shenyang Military Region, Shenyang 110016, Liaoning Province, China
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Cornide-Petronio ME, Fernández-López B, Barreiro-Iglesias A, Rodicio MC. Traumatic injury induces changes in the expression of the serotonin 1A receptor in the spinal cord of lampreys. Neuropharmacology 2014; 77:369-78. [PMID: 24490228 DOI: 10.1016/j.neuropharm.2013.10.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
After spinal cord injury (SCI) in mammals, the loss of serotonin coming from the brainstem reduces the excitability of motor neurons and leads to a compensatory overexpression of serotonin receptors. Despite the key role of the serotonin receptor 1a in the control of locomotion, little attention has been put in the study of this receptor after SCI. In contrast to mammals, lampreys recover locomotion after a complete SCI, so, studies in this specie could help to understand events that lead to recovery of function. Here, we showed that in lampreys there is an acute increase in the expression of the serotonin 1A receptor transcript (5-ht1a) after SCI and a few weeks later expression levels go back to normal rostrally and caudally to the lesion. Overexpression of the 5-ht1a in rostral levels after SCI has not been reported in mammals, suggesting that this could be part of the plastic events that lead to the recovery of function in lampreys. The analysis of changes in 5-ht1a expression by zones (periventricular region and horizontally extended grey matter) showed that they followed the same pattern of changes detected in the spinal cord as a whole, with the exception of the caudal periventricular layer, where no significant differences were observed between control and experimental animals at any time post lesion. This suggests that different molecular signals act on the periventricular cells of the rostral and caudal regions to injury site and thus affecting their response to the injury in terms of expression of the 5-ht1a.
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Altieri SC, Garcia-Garcia AL, Leonardo ED, Andrews AM. Rethinking 5-HT1A receptors: emerging modes of inhibitory feedback of relevance to emotion-related behavior. ACS Chem Neurosci 2013; 4:72-83. [PMID: 23336046 DOI: 10.1021/cn3002174] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 12/20/2012] [Indexed: 11/27/2022] Open
Abstract
The complexities of the involvement of the serotonin transmitter system in numerous biological processes and psychiatric disorders is, to a substantial degree, attributable to the large number of serotonin receptor families and subtypes that have been identified and characterized for over four decades. Of these, the 5-HT(1A) receptor subtype, which was the first to be cloned and characterized, has received considerable attention based on its purported role in the etiology and treatment of mood and anxiety disorders. 5-HT(1A) receptors function both at presynaptic (autoreceptor) and postsynaptic (heteroreceptor) sites. Recent research has implicated distinct roles for these two populations of receptors in mediating emotion-related behavior. New concepts as to how 5-HT(1A) receptors function to control serotonergic tone throughout life were highlights of the proceedings of the 2012 Serotonin Club Meeting in Montpellier, France. Here, we review recent findings and current perspectives on functional aspects of 5-HT(1A) auto- and heteroreceptors with particular regard to their involvement in altered anxiety and mood states.
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Affiliation(s)
| | - Alvaro L. Garcia-Garcia
- Department of Psychiatry, Division of Integrative Neuroscience, Columbia University and New York State Psychiatric Institute, New York, New York 10032, United States
| | - E. David Leonardo
- Department of Psychiatry, Division of Integrative Neuroscience, Columbia University and New York State Psychiatric Institute, New York, New York 10032, United States
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Gerlo S, Kooijman R, Beck IM, Kolmus K, Spooren A, Haegeman G. Cyclic AMP: a selective modulator of NF-κB action. Cell Mol Life Sci 2011; 68:3823-41. [PMID: 21744067 PMCID: PMC11114830 DOI: 10.1007/s00018-011-0757-8] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 06/10/2011] [Accepted: 06/16/2011] [Indexed: 10/18/2022]
Abstract
It has been known for several decades that cyclic AMP (cAMP), a prototypical second messenger, transducing the action of a variety of G-protein-coupled receptor ligands, has potent immunosuppressive and anti-inflammatory actions. These actions have been attributed in part to the ability of cAMP-induced signals to interfere with the function of the proinflammatory transcription factor Nuclear Factor-kappaB (NF-κB). NF-κB plays a crucial role in switching on the gene expression of a plethora of inflammatory and immune mediators, and as such is one of the master regulators of the immune response and a key target for anti-inflammatory drug design. A number of fundamental molecular mechanisms, contributing to the overall inhibitory actions of cAMP on NF-κB function, are well established. Paradoxically, recent reports indicate that cAMP, via its main effector, the protein kinase A (PKA), also promotes NF-κB activity. Indeed, cAMP actions appear to be highly cell type- and context-dependent. Importantly, several novel players in the cAMP/NF-κB connection, which selectively direct cAMP action, have been recently identified. These findings not only open up exciting new research avenues but also reveal novel opportunities for the design of more selective, NF-κB-targeting, anti-inflammatory drugs.
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Affiliation(s)
- Sarah Gerlo
- VIB Department of Medical Protein Research, Ghent University (UGent), Albert Baertsoenkaai, Belgium.
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Polter AM, Li X. Glycogen Synthase Kinase-3 is an Intermediate Modulator of Serotonin Neurotransmission. Front Mol Neurosci 2011; 4:31. [PMID: 22028682 PMCID: PMC3199786 DOI: 10.3389/fnmol.2011.00031] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 09/28/2011] [Indexed: 01/22/2023] Open
Abstract
Serotonin is a neurotransmitter with broad functions in brain development, neuronal activity, and behaviors; and serotonin is the prominent drug target in several major neuropsychiatric diseases. The multiple actions of serotonin are mediated by diverse serotonin receptor subtypes and associated signaling pathways. However, the key signaling components that mediate specific function of serotonin neurotransmission have not been fully identified. This review will provide evidence from biochemical, pharmacological, and animal behavioral studies showing that serotonin regulates the activation states of brain glycogen synthase kinase-3 (GSK3) via type 1 and type 2 serotonin receptors. In return, GSK3 directly interacts with serotonin receptors in a highly selective manner, with a prominent effect on modulating serotonin 1B receptor activity. Therefore, GSK3 acts as an intermediate modulator in the serotonin neurotransmission system, and balanced GSK3 activity is essential for serotonin-regulated brain function and behaviors. Particularly important, several classes of serotonin-modulating drugs, such as antidepressants and atypical antipsychotics, regulate GSK3 by inhibiting its activity in brain, which reinforces the importance of GSK3 as a potential therapeutic target in neuropsychiatric diseases associated with abnormal serotonin function.
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Affiliation(s)
- Abigail M Polter
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham Birmingham, AL, USA
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Polter AM, Yang S, Jope RS, Li X. Functional significance of glycogen synthase kinase-3 regulation by serotonin. Cell Signal 2011; 24:265-71. [PMID: 21946431 DOI: 10.1016/j.cellsig.2011.09.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 09/09/2011] [Indexed: 12/21/2022]
Abstract
Serotonin modulates brain physiology and behavior and has major roles in brain diseases involving abnormal mood and cognition. Enhancing brain serotonin has been found to regulate glycogen synthase Kinase-3 (GSK3), but the signaling mechanism and functional significance of this regulation remain to be determined. In this study, we tested the signaling mechanism mediating 5-HT1A receptor-regulated GSK3 in the hippocampus. Using mutant GSK3 knock-in mice, we also tested the role of GSK3 in the behavioral effects of 5-HT1A receptors and the serotonin reuptake inhibitor fluoxetine. The results showed that activation of 5-HT1A receptors by 8-hydroxy-N,N-dipropyl-2-aminotetralin (8-OH-DPAT) increased phosphorylation of the N-terminal serine of both GSK3α and GSK3β in several areas of the hippocampus. The effect of 8-OH-DPAT was accompanied by an increase in the active phosphorylation of Akt, and was blocked by LY294002, an inhibitor of phosphoinositide 3-kinases (PI3K). Phosphorylation of GSK3β, but not GSK3α, was necessary for 5-HT1A receptors to suppress the hippocampus-associated contextual fear learning. Furthermore, acute fluoxetine treatment up-regulated both phospho-Ser21-GSK3α and phospho-Ser9-GSK3β in the hippocampus. Blocking phosphorylation of GSK3α and GSK3β diminished the anti-immobility effect of fluoxetine treatment in the forced swim test, wherein the effect of GSK3β was more prominent. These results together suggest that PI3K/Akt is a signaling mechanism mediating the GSK3-regulating effect of 5-HT1A receptors in the hippocampus, and regulation of GSK3 is an important intermediate signaling process in the behavioral functions of 5-HT1A receptors and fluoxetine.
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Affiliation(s)
- Abigail M Polter
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
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Ganguly S, Saxena R, Chattopadhyay A. Reorganization of the actin cytoskeleton upon G-protein coupled receptor signaling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1921-9. [PMID: 21501584 DOI: 10.1016/j.bbamem.2011.04.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Revised: 03/29/2011] [Accepted: 04/01/2011] [Indexed: 12/28/2022]
Abstract
The actin cytoskeleton is involved in a multitude of cellular responses besides providing structural support. While the role of the actin cytoskeleton in cellular processes such as trafficking and motility has been extensively studied, reorganization of the actin cytoskeleton upon signaling by G-protein coupled receptors (GPCRs) represents a relatively unexplored area. The G-protein coupled receptor superfamily is an important protein family in mammals, involved in signal transduction across membranes. G-protein coupled receptors act as major signaling hubs and drug targets. The serotonin(1A) receptor is a representative member of the G-protein coupled receptor superfamily and plays a crucial role in the generation and modulation of various cognitive, developmental and behavioral functions. In order to monitor the changes in the actin cytoskeleton upon serotonin(1A) receptor signaling in a quantitative manner, we developed an approach based on high magnification imaging of F-actin in cells, followed by image reconstruction. Our results suggest that the actin cytoskeleton is reorganized in response to serotonin(1A) receptor signaling. In addition, we show that reorganization of the actin cytoskeleton is strongly dependent on adenosine 3',5'-cyclic monophosphate level, and is mediated by the activation of protein kinase A. Our results are consistent with the possibility of a feedback mechanism involving the actin cytoskeleton, adenosine 3',5'-cyclic monophosphate level and the serotonin(1A) receptor.
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Affiliation(s)
- Sourav Ganguly
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, India
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15
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Schipke CG, Heuser I, Peters O. Antidepressants act on glial cells: SSRIs and serotonin elicit astrocyte calcium signaling in the mouse prefrontal cortex. J Psychiatr Res 2011; 45:242-8. [PMID: 20619420 DOI: 10.1016/j.jpsychires.2010.06.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 06/02/2010] [Accepted: 06/08/2010] [Indexed: 11/24/2022]
Abstract
One important target in the treatment of major depressive disorder (MDD) is the serotonin (5-hydroxytryptamine, 5-HT) system. Selective serotonin reuptake inhibitors (SSRI) are used to treat MDD. Yet, the mode of action of these drugs is not completely understood. There is evolving evidence for a role of glutamate in mood disorder and its signaling. Astrocytes are involved in glutamate metabolism and play an active role in memory processing but their role in mood disorders is still largely unknown. A modulation of astrocytic signaling by SSRIs or 5-HT has not been investigated up to now. We investigated astrocytic calcium signaling with the calcium indicator dye Fluo-4. Using a confocal microscope, we imaged astrocytes in the medial prefrontal cortex of acute mouse brain slices after the application of the SSRIs citalopram and fluoxetine. In the same way, we studied the effects of serotonin and the modulation of this signaling by glutamate in astrocytes. We found that astrocyte calcium signaling can be elicited by 5-HT. Also, the SSRIs citalopram and fluoxetine induce calcium signals in about 1/3 of all astrocytes, even when neuronal signal propagation is inhibited. Astrocytic responses to 5-HT have a unique pattern and they could mostly not be evoked twice. We determined that glutamate is a substance that can interfere with 5-HT-induced calcium signals in astrocytes since after stimulation by glutamate, astrocytes did not show a response to 5-HT. Astrocytic calcium signaling is elicited by SSRIs and 5-HT. They may serve as integrators, linking the serotonergic and glutamatergic signaling pathways.
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Affiliation(s)
- Carola G Schipke
- Department of Psychiatry, Charité Universitätsmedizin Berlin, Campus Benjamin Franklin, Germany.
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Polter AM, Li X. 5-HT1A receptor-regulated signal transduction pathways in brain. Cell Signal 2010; 22:1406-12. [PMID: 20363322 PMCID: PMC2903656 DOI: 10.1016/j.cellsig.2010.03.019] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Accepted: 03/25/2010] [Indexed: 10/19/2022]
Abstract
Serotonin is an influential monoamine neurotransmitter that signals through a number of receptors to modulate brain function. Among different serotonin receptors, the serotonin 1A (5-HT1A) receptors have been tied to a variety of physiological and pathological processes, notably in anxiety, mood, and cognition. 5-HT1A receptors couple not only to the classical inhibitory G protein-regulated signaling pathway, but also to signaling pathways traditionally regulated by growth factors. Despite the importance of 5-HT1A receptors in brain function, little is known about how these signaling mechanisms link 5-HT1A receptors to regulation of brain physiology and behavior. Following a brief summary of the known physiological and behavioral effects of 5-HT1A receptors, this article will review the signaling pathways regulated by 5-HT1A receptors, and discuss the potential implication of these signaling pathways in 5-HT1A receptor-regulated physiological processes and behaviors.
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Affiliation(s)
- Abigail M. Polter
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Xiaohua Li
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294
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Calvo N, de Boland AR, Gentili C. PTH inactivates the AKT survival pathway in the colonic cell line Caco-2. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1803:343-51. [PMID: 20005908 DOI: 10.1016/j.bbamcr.2009.11.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 11/25/2009] [Accepted: 11/30/2009] [Indexed: 12/28/2022]
Abstract
In previous works, we found that PTH promotes the apoptosis of human Caco-2 intestinal cells, through the mitochondrial pathway. This study was conducted to investigate the modulation of different players implicated in the AKT survival pathway in PTH-induced intestinal cell apoptosis. We demonstrate, for the first time, that PTH modulates AKT phosphorylation in response to apoptosis via the serine/threonine phosphatase PP2A. PTH treatment induces an association of AKT with the catalytic subunit of PP2A and increases its phosphatase activity. PTH also promotes the translocation of PP2Ac from the cytosol to the mitochondria. Furthermore, our results suggest that PP2A plays a role in hormone-dependent Caco-2 cells viability and in the cleavage of caspase-3 and its substrate PARP. The cAMP pathway also contributes to PTH-mediated AKT dephosphorylation while PKC and p38 MAPK do not participate in this event. Finally, we show that PTH induces the dissociation between 14-3-3 and AKT, but the significance of this response remains unknown. In correlation with PTH-induced Bad dephosphorylation, the hormone also decreases the basal association of 14-3-3 and Bad. Overall, our data suggest that in Caco-2 cells, PP2A and the cAMP pathway act in concert to inactivate the AKT survival pathway in PTH-induced intestinal cell apoptosis.
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Affiliation(s)
- Natalia Calvo
- Department Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, (8000) Bahía Blanca, Argentina
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18
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Simpkins JW, Yi KD, Yang SH, Dykens JA. Mitochondrial mechanisms of estrogen neuroprotection. Biochim Biophys Acta Gen Subj 2009; 1800:1113-20. [PMID: 19931595 DOI: 10.1016/j.bbagen.2009.11.013] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 11/11/2009] [Accepted: 11/12/2009] [Indexed: 01/11/2023]
Abstract
Mitochondria have become a primary focus in our search not only for the mechanism(s) of neuronal death but also for neuroprotective drugs and therapies that can delay or prevent Alzheimer's disease and other chronic neurodegenerative conditions. This is because mitochrondria play a central role in regulating viability and death of neurons, and mitochondrial dysfunction has been shown to contribute to neuronal death seen in neurodegenerative diseases. In this article, we review the evidence for the role of mitochondria in cell death and neurodegeneration and provide evidence that estrogens have multiple effects on mitochondria that enhance or preserve mitochondrial function during pathologic circumstances such as excitotoxicity, oxidative stress, and others. As such, estrogens and novel non-hormonal analogs have come to figure prominently in our efforts to protect neurons against both acute brain injury and chronic neurodegeneration.
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Affiliation(s)
- James W Simpkins
- Department of Pharmacology & Neuroscience, Institute for Aging and Alzheimer's Disease Research, University of North Texas Health Science Center, Fort Worth, TX, USA.
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Role of protein phosphatases and mitochondria in the neuroprotective effects of estrogens. Front Neuroendocrinol 2009; 30:93-105. [PMID: 19410596 PMCID: PMC2835549 DOI: 10.1016/j.yfrne.2009.04.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 04/20/2009] [Accepted: 04/21/2009] [Indexed: 12/15/2022]
Abstract
In the present treatise, we provide evidence that the neuroprotective and mito-protective effects of estrogens are inexorably linked and involve the ability of estrogens to maintain mitochondrial function during neurotoxic stress. This is achieved by the induction of nuclear and mitochondrial gene expression, the maintenance of protein phosphatases levels in a manner that likely involves modulation of the phosphorylation state of signaling kinases and mitochondrial pro- and anti-apoptotic proteins, and the potent redox/antioxidant activity of estrogens. These estrogen actions are mediated through a combination of estrogens receptor (ER)-mediated effects on nuclear and mitochondrial transcription of protein vital to mitochondrial function, ER-mediated, non-genomic signaling and non-ER-mediated effects of estrogens on signaling and oxidative stress. Collectively, these multifaceted, coordinated action of estrogens leads to their potency in protecting neurons from a wide variety of acute insults as well as chronic neurodegenerative processes.
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Abstract
The Akt serine/threonine kinase (also called protein kinase B) has emerged as a critical signaling molecule within eukaryotic cells. Significant progress has been made in clarifying its regulation by upstream kinases and identifying downstream mechanisms that mediate its effects in cells and contribute to signaling specificity. Here, we provide an overview of present advances in the field regarding the function of Akt in physiological and pathological cell function within a more generalized framework of Akt signal transduction. An emphasis is placed on the involvement of Akt in human diseases ranging from cancer to metabolic dysfunction and mental disease.
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Affiliation(s)
- T F Franke
- Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA.
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