351
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In vivo positron emission tomographic imaging of glial responses to amyloid-beta and tau pathologies in mouse models of Alzheimer's disease and related disorders. J Neurosci 2011; 31:4720-30. [PMID: 21430171 DOI: 10.1523/jneurosci.3076-10.2011] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Core pathologies of Alzheimer's disease (AD) are aggregated amyloid-β peptides (Aβ) and tau, and the latter is also characteristic of diverse neurodegenerative tauopathies. These amyloid lesions provoke microglial activation, and recent neuroimaging technologies have enabled visualization of this response in living brains using radioligands for the peripheral benzodiazepine receptor also known as the 18 kDa translocator protein (TSPO). Here, we elucidated contributions of Aβ and tau deposits to in vivo TSPO signals in pursuit of mechanistic and diagnostic significance of TSPO imaging in AD and other tauopathies. A new antibody to human TSPO revealed induction of TSPO-positive microgliosis by tau fibrils in tauopathy brains. Emergence of TSPO signals before occurrence of brain atrophy and thioflavin-S-positive tau amyloidosis was also demonstrated in living mice transgenic for mutant tau by positron emission tomography (PET) with two classes of TSPO radioligands, [(11)C]AC-5216 and [(18)F]fluoroethoxy-DAA1106. Meanwhile, only modest TSPO elevation was observed in aged mice modeling Aβ plaque deposition, despite the notably enhanced in vivo binding of amyloid radiotracer, [(11)C]Pittsburgh Compound-B, to plaques. In these animals, [(11)C]AC-5216 yielded better TSPO contrasts than [(18)F]fluoroethoxy-DAA1106, supporting the possibility of capturing early neurotoxicity with high-performance TSPO probes. Furthermore, an additional line of mice modeling intraneuronal Aβ accumulation displayed elevated TSPO signals following noticeable neuronal loss, unlike TSPO upregulation heralding massive neuronal death in tauopathy model mice. Our data corroborate the utility of TSPO-PET imaging as a biomarker for tau-triggered toxicity, and as a complement to amyloid scans for diagnostic assessment of tauopathies with and without Aβ pathologies.
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352
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Tano JY, Vazquez G. Requirement for non-regulated, constitutive calcium influx in macrophage survival signaling. Biochem Biophys Res Commun 2011; 407:432-7. [PMID: 21414290 DOI: 10.1016/j.bbrc.2011.03.048] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Accepted: 03/10/2011] [Indexed: 10/18/2022]
Abstract
The phosphatidylinositol-3-kinase (PI3K)/AKT axis and the Nuclear Factor kappa B (NFκB) pathway play critical roles in macrophage survival. In cells other than macrophages proper operation of those two pathways requires Ca²(+) influx into the cell, but if that is the case in macrophages remains unexplored. In the present work we used THP-1-derived macrophages and a pharmacological approach to examine for the first time the role of constitutive, non-regulated Ca²(+) influx in PI3K/AKT and NFκB signaling. Blocking constitutive function of Ca²(+)-permeable channels with the organic channel blocker SKF96365 completely prevented phosphorylation of IκBα, AKT and its downstream target BAD in TNFα-treated macrophages. A similar effect was observed upon treating macrophages with the calmodulin (CAM) inhibitor W-7 or the calmodulin-dependent kinase II (CAMKII) inhibitor KN-62. In addition, pre-treating macrophages with SKF96365 significantly enhanced TNFα-induced apoptosis. Our findings suggest that in THP-1-derived macrophages survival signaling depends, to a significant extent, on constitutive Ca²(+) influx presumably through a mechanism that involves the CAM/CAMKII axis as a coupling component between constitutive Ca²(+) influx and activation of survival signaling.
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Affiliation(s)
- Jean-Yves Tano
- Department of Physiology and Pharmacology, University of Toledo College of Medicine, Health Science Campus, Toledo, OH 43614, USA
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353
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Gutierrez H, Davies AM. Regulation of neural process growth, elaboration and structural plasticity by NF-κB. Trends Neurosci 2011; 34:316-25. [PMID: 21459462 PMCID: PMC3115056 DOI: 10.1016/j.tins.2011.03.001] [Citation(s) in RCA: 170] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 02/23/2011] [Accepted: 03/01/2011] [Indexed: 11/12/2022]
Abstract
The nuclear factor-kappa B (NF-κB) family of transcription factors has recently emerged as a major regulator of the growth and elaboration of neural processes. NF-κB signaling has been implicated in controlling axon initiation, elongation, guidance and branching and in regulating dendrite arbor size and complexity during development and dendritic spine density in the adult. NF-κB is activated by a variety of extracellular signals, and either promotes or inhibits growth depending on the phosphorylation status of the p65 NF-κB subunit. These novel roles for NF-κB, together with recent evidence implicating NF-κB in the regulation of neurogenesis in the embryo and adult, have important implications for neural development and for learning and memory in the mature nervous system.
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Affiliation(s)
- Humberto Gutierrez
- Cardiff School of Biosciences, University of Cardiff, Biomedical Sciences Building 3, Cardiff CF10 3AT, UK
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354
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Abstract
Recent advances in chromatin biology have identified a role for epigenetic mechanisms in the regulation of neuronal gene expression changes, a necessary process for proper synaptic plasticity and memory formation. Experimental evidence for dynamic chromatin remodeling influencing gene transcription in postmitotic neurons grew from initial reports describing posttranslational modifications of histones, including phosphorylation and acetylation occurring in various brain regions during memory consolidation. An accumulation of recent studies, however, has also highlighted the importance of other epigenetic modifications, such as DNA methylation and histone methylation, as playing a role in memory formation. This present review examines learning-induced gene transcription by chromatin remodeling underlying long-lasting changes in neurons, with direct implications for the study of epigenetic mechanisms in long-term memory formation and behavior. Furthermore, the study of epigenetic gene regulation, in conjunction with transcription factor activation, can provide complementary lines of evidence to further understanding transcriptional mechanisms subserving memory storage.
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Affiliation(s)
- Farah D. Lubin
- Evelyn F. McKnight Brain Institute, Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Swati Gupta
- Evelyn F. McKnight Brain Institute, Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - R. Ryley Parrish
- Evelyn F. McKnight Brain Institute, Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nicola M. Grissom
- Evelyn F. McKnight Brain Institute, Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Robin L. Davis
- Evelyn F. McKnight Brain Institute, Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
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355
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Riquelme D, Alvarez A, Leal N, Adasme T, Espinoza I, Valdés JA, Troncoso N, Hartel S, Hidalgo J, Hidalgo C, Carrasco MA. High-frequency field stimulation of primary neurons enhances ryanodine receptor-mediated Ca2+ release and generates hydrogen peroxide, which jointly stimulate NF-κB activity. Antioxid Redox Signal 2011; 14:1245-59. [PMID: 20836702 DOI: 10.1089/ars.2010.3238] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Neuronal electrical activity increases intracellular Ca(2+) concentration and generates reactive oxygen species. Here, we show that high frequency field stimulation of primary hippocampal neurons generated Ca(2+) signals with an early and a late component, and promoted hydrogen peroxide generation via a neuronal NADPH oxidase. Hydrogen peroxide generation required both Ca(2+) entry through N-methyl-D-aspartate receptors and Ca(2+) release mediated by ryanodine receptors (RyR). Field stimulation also enhanced nuclear translocation of the NF-κB p65 protein and NF-κB -dependent transcription, and increased c-fos mRNA and type-2 RyR protein content. Preincubation with inhibitory ryanodine or with the antioxidant N-acetyl L-cysteine abolished the increase in hydrogen peroxide generation and the late Ca(2+) signal component induced by electrical stimulation. Primary cortical cells behaved similarly as primary hippocampal cells. Exogenous hydrogen peroxide also activated NF-κB-dependent transcription in hippocampal neurons; inhibitory ryanodine prevented this effect. Selective inhibition of the NADPH oxidase or N-acetyl L-cysteine also prevented the enhanced translocation of p65 in hippocampal cells, while N-acetyl L-cysteine abolished the increase in RyR2 protein content induced by high frequency stimulation. In conclusion, the present results show that electrical stimulation induced reciprocal activation of ryanodine receptor-mediated Ca(2+) signals and hydrogen peroxide generation, which stimulated jointly NF-κB activity.
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Affiliation(s)
- Denise Riquelme
- Center of Molecular Studies of the Cell, Institute of Biomedical Sciences Programs, Universidad de Chile, Santiago, Chile
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356
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Napolitano M, Costa L, Palermo R, Giovenco A, Vacca A, Gulino A. Protective effect of pioglitazone, a PPARγ ligand, in a 3 nitropropionic acid model of Huntington's disease. Brain Res Bull 2011; 85:231-7. [PMID: 21440606 DOI: 10.1016/j.brainresbull.2011.03.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 03/15/2011] [Accepted: 03/18/2011] [Indexed: 11/17/2022]
Abstract
The peroxisome proliferator-activated receptor γ (PPARγ) is a member of the PPAR family. PPARγ is the target of insulin-sensitising thiazolidinediones (TZDs), drugs used for the treatment of non-insulin-dependent diabetes. Recently, several studies have shown that PPARγ activators can also prevent or attenuate neurodegeneration. The PPARγ agonist pioglitazone provides neuroprotection to dopaminergic neurons in lipopolysaccharide (LPS) and MPTP-induced Parkinson's disease experimental models. Here, we investigated whether PPARγ activation by pioglitazone protected striatal cells from mitochondrial dysfunction and oxidative stress in a 3 nitropropionic acid (3NP)-induced experimental model of Huntington's disease (HD). Our results suggested that pioglitazone has beneficial effects on mitochondrial dysfunction by interfering with the NF-κB signalling pathway, which has been implicated in the pathogenesis of HD. Additionally, we demonstrated that the nuclear translocation of HDAC3 is regulated by 3NP via IκBα and that treatment with pioglitazone prevented these effects. These results suggested that IκBα-dependent nuclear translocation is responsible for PPARγ inhibition by 3NP and pointed to histone modifications as a novel approach for treating HD.
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Affiliation(s)
- Maddalena Napolitano
- University La Sapienza ROME, Department of Molecular Medicine, Viale Regina Elena, 324, 00161 Rome, Italy.
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357
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Epigenetic gene regulation in the adult mammalian brain: multiple roles in memory formation. Neurobiol Learn Mem 2011; 96:68-78. [PMID: 21419233 DOI: 10.1016/j.nlm.2011.03.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 02/25/2011] [Accepted: 03/04/2011] [Indexed: 12/24/2022]
Abstract
Brain-derived neurotrophic factor (bdnf) is one of numerous gene products necessary for long-term memory formation and dysregulation of bdnf has been implicated in the pathogenesis of cognitive and mental disorders. Recent work indicates that epigenetic-regulatory mechanisms including the markings of histone proteins and associated DNA remain labile throughout the life-span and represent an attractive molecular process contributing to gene regulation in the brain. In this review, important information will be discussed on epigenetics as a set of newly identified dynamic transcriptional mechanisms serving to regulate gene expression changes in the adult brain with particular emphasis on bdnf transcriptional readout in learning and memory formation. This review will also highlight evidence for the role of epigenetics in aberrant bdnf gene regulation in the pathogenesis of cognitive dysfunction associated with seizure disorders, Rett syndrome, Schizophrenia, and Alzheimer's disease. Such research offers novel concepts for understanding epigenetic transcriptional mechanisms subserving adult cognition and mental health, and furthermore promises novel avenues for therapeutic approach in the clinic.
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358
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Ch'ng TH, Martin KC. Synapse-to-nucleus signaling. Curr Opin Neurobiol 2011; 21:345-52. [PMID: 21349698 DOI: 10.1016/j.conb.2011.01.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2011] [Revised: 01/31/2011] [Accepted: 01/31/2011] [Indexed: 12/21/2022]
Abstract
Signals generated in distal subcellular compartments of neurons must often travel long distances to the nucleus to trigger changes in gene expression. This retrograde signaling is critical to the development, function, and survival of neural circuits, and neurons have evolved multiple mechanisms to transmit signals over long distances. In this review, we briefly summarize the range of mechanisms whereby distally generated signals are transported to neuronal nuclei. We then focus on the transport of soluble signals from the synapse to the nucleus during neuronal plasticity.
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Affiliation(s)
- Toh Hean Ch'ng
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095-1737, United States
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359
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Behnisch T, Yuanxiang P, Bethge P, Parvez S, Chen Y, Yu J, Karpova A, Frey JU, Mikhaylova M, Kreutz MR. Nuclear translocation of jacob in hippocampal neurons after stimuli inducing long-term potentiation but not long-term depression. PLoS One 2011; 6:e17276. [PMID: 21364755 PMCID: PMC3041791 DOI: 10.1371/journal.pone.0017276] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 01/28/2011] [Indexed: 12/22/2022] Open
Abstract
Background In recent years a number of potential synapto-nuclear protein messengers have been characterized that are thought to be involved in plasticity-related gene expression, and that have the capacity of importin- mediated and activity-dependent nuclear import. However, there is a surprising paucity of data showing the nuclear import of such proteins in cellular models of learning and memory. Only recently it was found that the transcription factor cyclic AMP response element binding protein 2 (CREB2) transits to the nucleus during long-term depression (LTD), but not during long-term potentiation (LTP) of synaptic transmission in hippocampal primary neurons. Jacob is another messenger that couples NMDA-receptor-activity to nuclear gene expression. We therefore aimed to study whether Jacob accumulates in the nucleus in physiological relevant models of activity-dependent synaptic plasticity. Methodology/Principal Findings We have analyzed the dynamics of Jacob's nuclear import following induction of NMDA-receptor dependent LTP or LTD at Schaffer collateral-CA1 synapses in rat hippocampal slices. Using time-lapse imaging of neurons expressing a Jacob-Green-Fluorescent-Protein we found that Jacob rapidly translocates from dendrites to the nucleus already during the tetanization period of LTP, but not after induction of LTD. Immunocytochemical stainings confirmed the nuclear accumulation of endogenous Jacob in comparison to apical dendrites after induction of LTP but not LTD. Complementary findings were obtained after induction of NMDA-receptor dependent chemical LTP and LTD in hippocampal primary neurons. However, in accordance with previous studies, high concentrations of NMDA and glycine as well as specific activation of extrasynaptic NMDA-receptors resembling pathological conditions induce an even more profound increase of nuclear Jacob levels. Conclusions/Significance Taken together, these findings suggest that the two major forms of NMDA-receptor dependent synaptic plasticity, LTP and LTD, elicit the transition of different synapto-nuclear messengers albeit in both cases importin-mediated retrograde transport and NMDA-receptor activation is required.
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Affiliation(s)
- Thomas Behnisch
- Institutes of Brain Science, Fudan University, Shanghai, China.
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360
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Johnson AW, Crombag HS, Smith DR, Ramanan N. Effects of serum response factor (SRF) deletion on conditioned reinforcement. Behav Brain Res 2011; 220:312-8. [PMID: 21329726 DOI: 10.1016/j.bbr.2011.02.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 02/08/2011] [Accepted: 02/08/2011] [Indexed: 01/06/2023]
Abstract
Serum response factor (SRF) is a ubiquitously expressed stimulus-dependent transcription factor that regulates gene expression by binding to serum response element in the promoter region of target genes. Recent studies in mice have shown that SRF is important for activity-dependent gene expression and synaptic plasticity in the adult brain but is dispensable for neuronal survival. Given these important functions of SRF in the CNS, it is expected to play a critical role in several aspects of learning and memory. Here we evaluated the role of SRF in conditioned reinforcement using two lines of conditional SRF mutant mice. These SRF mutant mice exhibited different spatial patterns of SRF deletion in the post-natal forebrain and notably within the hippocampus. SRF deletion was more widespread in SRF-CKCre mutants than in SRF-SynCre mutants, particularly in areas of the cortex and striatum. Mutant and wild-type mice were trained to associate one auditory cue (CS+) with reward, whereas a second cue remained relatively neutral (CS-). All mice readily acquired this discrimination, entering the food cup during CS+ but not during CS-. In a subsequent test of conditioned reinforcement, in the absence of food, wild-type control mice and SRF-SynCre mice learned to selectively perform an instrumental response that yielded CS+ presentation rather than another response that produced CS-. SRF-CKCre mutants failed to show this preferential responding for CS+. These results suggest a role for SRF in conditioned reinforcement, a manifestation of incentive learning that has been implicated in many aspects of adaptive and maladaptive behavior, such as substance abuse and eating disorders.
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Affiliation(s)
- A W Johnson
- Neurogenetics and Behavior Center, Department of Psychological & Brain Sciences, The Johns Hopkins University, Baltimore, MD, USA.
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361
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Nazarian J, Berry DL, Sanjari S, Razvi M, Brown K, Hathout Y, Vertes A, Dadgar S, Hoffman EP. Evolution and comparative genomics of subcellular specializations: EST sequencing of Torpedo electric organ. Mar Genomics 2011; 4:33-40. [PMID: 21429463 DOI: 10.1016/j.margen.2010.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 12/09/2010] [Accepted: 12/13/2010] [Indexed: 02/04/2023]
Abstract
Uncharacterized open reading frames (ORFs) in human genomic sequence often show a high degree of evolutionary conservation, yet have little or no tissue EST or protein data suggestive of protein product function. The encoded proteins may have highly restricted expression in specialized cells, subcellular specializations, and/or narrow windows during development. One such highly specialized and minute subcellular compartment is the neuromuscular junction (NMJ), where motorneurons contact muscle fibers. The electric Torpedo ray has evolved to expand the NMJ structure to the size of a large organ (electroplax organ), and we hypothesized that Torpedo electroplax proteins would be candidates for human ESTs expressed at the human NMJ. A total of 9719 primary electroplax cDNA clones were sequenced. We identified 44 human ORFs showing high (>63%) amino acid identity to Torpedo electroplax transcripts with enrichment for mRNA splicing motifs (SH2 and pre-mRNA splicing domains), an observation potentially important for the strict nuclear domains maintained by myonuclei underlying the NMJ. We generated antibodies against two uncharacterized human genes (C19orf29 [Drosophila cactin] and C15orf24) and showed that these were indeed expressed at the murine NMJ. Cactin, a member of the Rel transcription factor family in Drosophila, localized to the postsynaptic cytosol of the NMJ and nuclear membrane. C15orf24 protein localized to the murine postsynaptic sarcolemma. We show a novel approach towards identifying proteins expressed at a subcellular specialization using evolutionary diversity of organ function and cross-species mapping.
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Affiliation(s)
- Javad Nazarian
- Research Center for Genetic Medicine, Children's National Medical Center, Department of Integrative Systems Biology, The George Washington University School of Medicine & Health Sciences, Washington, DC 20010, United States
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362
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IκB kinase regulates social defeat stress-induced synaptic and behavioral plasticity. J Neurosci 2011; 31:314-21. [PMID: 21209217 DOI: 10.1523/jneurosci.4763-10.2011] [Citation(s) in RCA: 225] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The neurobiological underpinnings of mood and anxiety disorders have been linked to the nucleus accumbens (NAc), a region important in processing the rewarding and emotional salience of stimuli. Using chronic social defeat stress, an animal model of mood and anxiety disorders, we investigated whether alterations in synaptic plasticity are responsible for the long-lasting behavioral symptoms induced by this form of stress. We hypothesized that chronic social defeat stress alters synaptic strength or connectivity of medium spiny neurons (MSNs) in the NAc to induce social avoidance. To test this, we analyzed the synaptic profile of MSNs via confocal imaging of Lucifer-yellow-filled cells, ultrastructural analysis of the postsynaptic density, and electrophysiological recordings of miniature EPSCs (mEPSCs) in mice after social defeat. We found that NAc MSNs have more stubby spine structures with smaller postsynaptic densities and an increase in the frequency of mEPSCs after social defeat. In parallel to these structural changes, we observed significant increases in IκB kinase (IKK) in the NAc after social defeat, a molecular pathway that has been shown to regulate neuronal morphology. Indeed, we find using viral-mediated gene transfer of dominant-negative and constitutively active IKK mutants that activation of IKK signaling pathways during social defeat is both necessary and sufficient to induce synaptic alterations and behavioral effects of the stress. These studies establish a causal role for IKK in regulating stress-induced adaptive plasticity and may present a novel target for drug development in the treatment of mood and anxiety disorders in humans.
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363
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Singh MV, Anderson ME. Is CaMKII a link between inflammation and hypertrophy in heart? J Mol Med (Berl) 2011; 89:537-43. [PMID: 21279501 DOI: 10.1007/s00109-011-0727-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2010] [Revised: 12/09/2010] [Accepted: 01/13/2011] [Indexed: 10/18/2022]
Abstract
Myocardial infarction is a major cause of morbidity and mortality in the developing and developed world. Although current interventions have been successful in prolonging life, they are inadequate because mortality is still high among MI patients. The multifunctional Ca(2+)/calmodulin-dependent protein kinase (CaMKII) plays a key role in the structure and contractility of the myocardium. CaMKII activity is increased in MI hearts and CaMKII promotes cardiac hypertrophy and inflammation, processes consistently activated by myocardial injury. Hypertrophy and inflammation are also related to neurohumoral and redox signaling which uncouple CaMKII activation from Ca(2+)/calmodulin dependence. Thus, CaMKII may act as a nodal point for integrating hypertrophic and inflammatory signaling in myocardium.
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Affiliation(s)
- Madhu V Singh
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, 52242, USA.
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364
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Azoulay-Alfaguter I, Yaffe Y, Licht-Murava A, Urbanska M, Jaworski J, Pietrokovski S, Hirschberg K, Eldar-Finkelman H. Distinct molecular regulation of glycogen synthase kinase-3alpha isozyme controlled by its N-terminal region: functional role in calcium/calpain signaling. J Biol Chem 2011; 286:13470-80. [PMID: 21266584 DOI: 10.1074/jbc.m110.127969] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Glycogen synthase kinase-3 (GSK-3) is expressed as two isozymes α and β. They share high similarity in their catalytic domains but differ in their N- and C-terminal regions, with GSK-3α having an extended glycine-rich N terminus. Here, we undertook live cell imaging combined with molecular and bioinformatic studies to understand the distinct functions of the GSK-3 isozymes focusing on GSK-3α N-terminal region. We found that unlike GSK-3β, which shuttles between the nucleus and cytoplasm, GSK-3α was excluded from the nucleus. Deletion of the N-terminal region of GSK-3α resulted in nuclear localization, and treatment with leptomycin B resulted in GSK-3α accumulation in the nucleus. GSK-3α rapidly accumulated in the nucleus in response to calcium or serum deprivation, and accumulation was strongly inhibited by the calpain inhibitor calpeptin. This nuclear accumulation was not mediated by cleavage of the N-terminal region or phosphorylation of GSK-3α. Rather, we show that calcium-induced GSK-3α nuclear accumulation was governed by GSK-3α binding with as yet unknown calpain-sensitive protein or proteins; this binding was mediated by the N-terminal region. Bioinformatic and experimental analyses indicated that nuclear exclusion of GSK-3α was likely an exclusive characteristic of mammalian GSK-3α. Finally, we show that nuclear localization of GSK-3α reduced the nuclear pool of β-catenin and its target cyclin D1. Taken together, these data suggest that the N-terminal region of GSK-3α is responsible for its nuclear exclusion and that binding with a calcium/calpain-sensitive product enables GSK-3α nuclear retention. We further uncovered a novel link between calcium and nuclear GSK-3α-mediated inhibition of the canonical Wnt/β-catenin pathway.
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Affiliation(s)
- Inbar Azoulay-Alfaguter
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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365
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Chou CW, Wong GTC, Lim G, McCabe MF, Wang S, Irwin MG, Mao J. Peripheral nerve injury alters the expression of NF-κB in the rat's hippocampus. Brain Res 2011; 1378:66-71. [PMID: 21223950 DOI: 10.1016/j.brainres.2011.01.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 01/04/2011] [Accepted: 01/04/2011] [Indexed: 02/02/2023]
Abstract
The hippocampus plays an important role in learning and memory and possibly contributes to the formation of pain-related memory and emotional responses. However, there is currently little data linking the hippocampus to neuropathic pain. It has been reported that NF-κB is an important regulatory factor in memory consolidation within the hippocampus. This study aims to examine a possible relationship between the hippocampal NF-κB expression and nerve injury-induced thermal hyperalgesia using a rat model of constriction sciatic nerve injury (CCI). Immunofluorescence and Western blot analysis were performed to detect and quantify the hippocampal NF-κB expression. Thermal hyperalgesia was examined on day 0 and postoperative days 1, 7 and 14. The nuclear portion of the p65 NF-κB expression was significantly increased on the contralateral side on days 7 and 14 as well as significantly increased on the ipsilateral side on day 14 as compared to the sham control group. Intraperitoneal administration of MK-801, an N-methyl-d-aspartate (NMDA) receptor antagonist, reduced hyperalgesia and modulated the NF-κB expression in the contralateral side of hippocampus. These results suggest an association between the hippocampal NF-κB expression and the behavioral manifestation of thermal hyperalgesia, which is likely to be mediated through activation of the NMDA receptor.
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Affiliation(s)
- Chiu-Wen Chou
- MGH Center for Translational Pain Research, Department of Anesthesia and Critical Care, WACC 324, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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366
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Emmanouil M, Taoufik E, Tseveleki V, Vamvakas SS, Probert L. A role for neuronal NF-κB in suppressing neuroinflammation and promoting neuroprotection in the CNS. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 691:575-81. [PMID: 21153363 DOI: 10.1007/978-1-4419-6612-4_60] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Mary Emmanouil
- Laboratory of Molecular Genetics, Hellenic Pasteur Institute, Athens, 11521, Greece
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367
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Chou CW, Wong GT, Lim G, Wang S, Irwin MG, Mao J. Spatiotemporal pattern of concurrent spinal and supraspinal NF-κB expression after peripheral nerve injury. THE JOURNAL OF PAIN 2011; 12:13-21. [PMID: 20537956 PMCID: PMC2978259 DOI: 10.1016/j.jpain.2010.03.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 03/02/2010] [Accepted: 03/24/2010] [Indexed: 01/09/2023]
Abstract
UNLABELLED The expression of NF-κB in the spinal cord is associated with neuropathic pain. However, little is known about its expression beyond the spinal cord. Here we examined a spatial and temporal pattern of the NF-κB expression in both spinal and supraspinal regions. After chronic constriction injury (CCI) of the sciatic nerve, NF-κB (p65) expression was significantly increased in the ipsilateral spinal cord. In contrast, the NF-κB expression in the contralateral primary somatosensory cortex was decreased with no significant differences seen in the thalamus. In the contralateral anterior cingulate cortex, the NF-κB expression was increased significantly on day 14 as compared with the sham group. In the contralateral amygdala, the NF-κB expression showed a time-dependent downregulation after CCI, which became significant on day 14. MK-801 reduced nociceptive behaviors and reversed the direction of NF-κB expression. These results indicate that the CCI-induced expression of p65 NF-κB is both time-dependent and region-specific, in areas that process both sensory-discriminative and motivational-affective dimensions of pain. PERSPECTIVE This article presents a spatiotemporal mapping of the NF-κB expression in spinal and supraspinal regions after peripheral nerve injury. These findings point to an involvement of NF-κB beyond the spinal cord in both the sensory discriminative and emotional affective aspects of neuropathic pain processing.
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Affiliation(s)
- Chiu-Wen Chou
- MGH Center for Translational Pain Research, Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114
- Department of Anaesthesiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Gordon T.C. Wong
- Department of Anaesthesiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Grewo Lim
- MGH Center for Translational Pain Research, Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114
| | - Shuxing Wang
- MGH Center for Translational Pain Research, Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114
| | - Michael G. Irwin
- Department of Anaesthesiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Jianren Mao
- MGH Center for Translational Pain Research, Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114
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368
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Activity-dependent calcium signaling and ERK-MAP kinases in neurons: a link to structural plasticity of the nucleus and gene transcription regulation. Cell Calcium 2010; 49:296-305. [PMID: 21163523 DOI: 10.1016/j.ceca.2010.11.009] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 11/15/2010] [Accepted: 11/16/2010] [Indexed: 12/11/2022]
Abstract
Activity-dependent gene expression is important for the formation and maturation of neuronal networks, neuronal survival and for plastic modifications within mature networks. At the level of individual neurons, expression of new protein is required for dendritic branching, synapse formation and elimination. Experience-driven synaptic activity induces membrane depolarization, which in turn evokes intracellular calcium transients that are decoded according to their source and strength by intracellular calcium sensing proteins. In order to activate the gene transcription machinery of the cell, calcium signals have to be conveyed from the site of their generation in the cytoplasm to the cell nucleus. This can occur via a variety of mechanisms and with different kinetics depending on the source and amplitude of calcium influx. One mechanism involves the propagation of calcium itself, leading to nuclear calcium transients that subsequently activate transcription. The mitogen-activated protein kinase (MAPK) cascade represents a second central signaling module that transduces information from the site of calcium signal generation at the plasma membrane to the nucleus. Nuclear signaling of the MAPK cascades catalyzes the phosphorylation of transcription factors but also regulates gene transcription more globally at the level of chromatin remodeling as well as through its recently identified role in the modulation of nuclear shape. Here we discuss the possible mechanisms by which the MAPKs ERK1 and ERK2, activated by synaptically evoked calcium influx, can signal to the nucleus and regulate gene transcription. Moreover, we describe how MAPK-dependent structural plasticity of the nuclear envelope enhances nuclear calcium signaling and suggest possible implications for the regulation of gene transcription in the context of nuclear geometry.
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369
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Abstract
The nuclear factor kappa B (NF-kappaB) transcription factor system plays multiple roles in the function of the nervous system during development and postnatal physiology. In the developing nervous system, neurite outgrowth could be regulated by both canonical and alternative NF-kappaB signaling pathways. The degree and site of NF-kappaB activation could promote or inhibit neuronal survival in a complex, signal and subunit-dependent manner. The significance and mechanistic basis of some of NF-kappaB activity in neurons have remained controversial. We discuss our current understanding and recent findings with regard to the roles of NF-kappaB in the neurite outgrowth and neuronal survival, and how NF-kappaB activation is associated with the pathophysiology of ischemic/ traumatic injuries and neurodegenerative diseases.
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Affiliation(s)
- Felicia Yu Hsuan Teng
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University Health System, National University ofSingapore, 8 Medical Drive, Singapore 117597
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370
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Iron overload triggers redox-sensitive signals in human IMR-32 neuroblastoma cells. Neurotoxicology 2010; 32:75-82. [PMID: 21130806 DOI: 10.1016/j.neuro.2010.11.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 11/25/2010] [Accepted: 11/25/2010] [Indexed: 12/28/2022]
Abstract
Excessive neuronal iron has been proposed to contribute to the pathology of several neurodegenerative diseases including Alzheimer's and Parkinson's diseases. This work characterized human neuroblastoma IMR-32 cells exposure to ferric ammonium citrate (FAC) as a model of neuronal iron overload and neurodegeneration. The consequences of FAC treatment on neuronal oxidative stress and on the modulation of the oxidant-sensitive transcription factors AP-1 and NF-κB were investigated. Incubation with FAC (150μM) resulted in a time (3-72h)-dependent increase in cellular iron content, and was associated with cell oxidant increase. FAC caused a time-dependent (3-48h) increase in nuclear AP-1- and NF-κB-DNA binding. This was associated with the upstream activation of the mitogen activated kinases ERK1/2, p38 and JNK and of IκBα phosphorylation and degradation. After 72h incubation with FAC, cell viability was 40% lower than in controls. Iron overload caused apoptotic cell death. After 48-72h of incubation with FAC, caspase 3 activity was increased, and chromatin condensation and nuclear fragmentation were observed. In summary, the exposure of IMR-32 cells to FAC is associated with increased oxidant cell levels, activation of redox-sensitive signals, and apoptosis.
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371
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Lanzillotta A, Sarnico I, Ingrassia R, Boroni F, Branca C, Benarese M, Faraco G, Blasi F, Chiarugi A, Spano P, Pizzi M. The acetylation of RelA in Lys310 dictates the NF-κB-dependent response in post-ischemic injury. Cell Death Dis 2010; 1:e96. [PMID: 21368872 PMCID: PMC3032326 DOI: 10.1038/cddis.2010.76] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The activation of nuclear factor kappa B (NF-κB) p50/RelA is a key event in ischemic neuronal injury, as well as in brain ischemic tolerance. We tested whether epigenetic mechanisms affecting the acetylation state of RelA might discriminate between neuroprotective and neurotoxic activation of NF-κB during ischemia. NF-κB activation and RelA acetylation were investigated in cortices of mice subjected to preconditioning brain ischemia or lethal middle cerebral artery occlusion (MCAO) and primary cortical neurons exposed to preconditioning or lethal oxygen-glucose deprivation (OGD). In mice subjected to MCAO and in cortical neurons exposed to lethal OGD, activated RelA displayed a high level of Lys310 acetylation in spite of reduced total acetylation. Also, acetylated RelA on Lys310 interacted strongly with the CREB-binding protein (CBP). Conversely, RelA activated during preconditioning ischemia appeared deacetylated on Lys310. Overexpressing RelA increased Bim promoter activity and neuronal cell death both induced by lethal OGD, whereas overexpressing the acetylation-resistant RelA-K310R, carrying a mutation from Lys310 to arginine, prevented both responses. Pharmacological manipulation of Lys310 acetylation by the sirtuin 1 activator resveratrol repressed the activity of the Bim promoter and reduced the neuronal cell loss. We conclude that the acetylation of RelA in Lys310 dictates NF-κB-dependent pro-apoptotic responses and represents a suitable target to dissect pathological from neuroprotective NF-κB activation in brain ischemia.
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Affiliation(s)
- A Lanzillotta
- Division of Pharmacology and Experimental Therapeutics, Department of Biomedical Sciences & Biotechnologies, School of Medicine, University of Brescia, Istituto Nazionale di Neuroscienze Brescia, Italy
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372
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Li J, Gu X, Ma Y, Calicchio ML, Kong D, Teng YD, Yu L, Crain AM, Vartanian TK, Pasqualini R, Arap W, Libermann TA, Snyder EY, Sidman RL. Nna1 mediates Purkinje cell dendritic development via lysyl oxidase propeptide and NF-κB signaling. Neuron 2010; 68:45-60. [PMID: 20920790 DOI: 10.1016/j.neuron.2010.08.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2010] [Indexed: 01/19/2023]
Abstract
The molecular pathways controlling cerebellar Purkinje cell dendrite formation and maturation are poorly understood. The Purkinje cell degeneration (pcd) mutant mouse is characterized by mutations in Nna1, a gene discovered in an axonal regenerative context, but whose actual function in development and disease is unknown. We found abnormal development of Purkinje cell dendrites in postnatal pcd(Sid) mice and linked this deficit to a deletion mutation in exon 7 of Nna1. With single cell gene profiling and virus-based gene transfer, we analyzed a molecular pathway downstream to Nna1 underlying abnormal Purkinje cell dendritogenesis in pcd(Sid) mice. We discovered that mutant Nna1 dramatically increases intranuclear localization of lysyl oxidase propeptide, which interferes with NF-κB RelA signaling and microtubule-associated protein regulation of microtubule stability, leading to underdevelopment of Purkinje cell dendrites. These findings provide insight into Nna1's role in neuronal development and why its absence renders Purkinje cells more vulnerable.
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Affiliation(s)
- Jianxue Li
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.
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373
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Sen N, Snyder SH. Protein modifications involved in neurotransmitter and gasotransmitter signaling. Trends Neurosci 2010; 33:493-502. [PMID: 20843563 DOI: 10.1016/j.tins.2010.07.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 07/20/2010] [Accepted: 07/27/2010] [Indexed: 02/07/2023]
Abstract
Covalent modifications of intracellular proteins, such as phosphorylation, are generally thought to occur as secondary or tertiary responses to neurotransmitters, following the intermediation of membrane receptors and second messengers such as cyclic AMP. By contrast, the gasotransmitter nitric oxide directly S-nitrosylates cysteine residues in diverse intracellular proteins. Recently, hydrogen sulfide has been acknowledged as a gasotransmitter, which analogously sulfhydrates cysteine residues in proteins. Cysteine residues are also modified by palmitoylation in response to neurotransmitter signaling, possibly in reciprocity with S-nitrosylation. Neurotransmission also elicits sumoylation and acetylation of lysine residues within diverse proteins. This review addresses how these recently appreciated protein modifications impact our thinking about ways in which neurotransmission regulates intracellular protein disposition.
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Affiliation(s)
- Nilkantha Sen
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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374
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Marcora E, Kennedy MB. The Huntington's disease mutation impairs Huntingtin's role in the transport of NF-κB from the synapse to the nucleus. Hum Mol Genet 2010; 19:4373-84. [PMID: 20739295 DOI: 10.1093/hmg/ddq358] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Expansion of a polyglutamine (polyQ) tract in the Huntingtin (Htt) protein causes Huntington's disease (HD), a fatal inherited neurodegenerative disorder. Loss of the normal function of Htt is thought to be an important pathogenetic component of HD. However, the function of wild-type Htt is not well defined. Htt is thought to be a multifunctional protein that plays distinct roles in several biological processes, including synaptic transmission, intracellular transport and neuronal transcription. Here, we show with biochemical and live cell imaging studies that wild-type Htt stimulates the transport of nuclear factor κ light-chain-enhancer of activated B cells (NF-κB) out of dendritic spines (where NF-κB is activated by excitatory synaptic input) and supports a high level of active NF-κB in neuronal nuclei (where NF-κB stimulates the transcription of target genes). We show that this novel function of Htt is impaired by the polyQ expansion and thus may contribute to the etiology of HD.
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Affiliation(s)
- Edoardo Marcora
- Division of Biology, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA
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375
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Wang J, Fu XQ, Lei WL, Wang T, Sheng AL, Luo ZG. Nuclear factor kappaB controls acetylcholine receptor clustering at the neuromuscular junction. J Neurosci 2010; 30:11104-13. [PMID: 20720118 PMCID: PMC6633475 DOI: 10.1523/jneurosci.2118-10.2010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 06/29/2010] [Accepted: 07/02/2010] [Indexed: 11/21/2022] Open
Abstract
At the vertebrate neuromuscular junction (NMJ), acetylcholine receptor (AChR) clustering is stimulated by motor neuron-derived glycoprotein Agrin and requires a number of intracellular signal or structural proteins, including AChR-associated scaffold protein Rapsyn. Here, we report a role of nuclear factor kappaB (NF-kappaB), a well known transcription factor involved in a variety of immune responses, in regulating AChR clustering at the NMJ. We found that downregulating the expression of RelA/p65 subunit of NF-kappaB or inhibiting NF-kappaB activity by overexpression of mutated form of IkappaB (inhibitor kappaB), which is resistant to proteolytic degradation and thus constitutively keeps NF-kappaB inactive in the cytoplasma, impeded the formation of AChR clusters in cultured C2C12 muscle cells stimulated by Agrin. In contrast, overexpression of RelA/p65 promoted AChR clustering. Furthermore, we investigated the mechanism by which NF-kappaB regulates AChR clustering. Interestingly, we found that downregulating the expression of RelA/p65 caused a marked reduction in the protein and mRNA level of Rapsyn and upregulation of RelA/p65 enhanced Rapsyn promoter activity. Mutation of NF-kappaB binding site on Rapsyn promoter prevented responsiveness to RelA/p65 regulation. Moreover, forced expression of Rapsyn in RelA/p65 downregulated muscle cells partially rescued AChR clusters, suggesting that NF-kappaB regulates AChR clustering, at least partially through the transcriptional regulation of Rapsyn. In line with this notion, genetic ablation of RelA/p65 selectively in the skeletal muscle caused a reduction of AChR density at the NMJ and a decrease in the level of Rapsyn. Thus, NF-kappaB signaling controls AChR clustering through transcriptional regulation of synaptic protein Rapsyn.
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Affiliation(s)
- Jia Wang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiu-Qing Fu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Wen-Liang Lei
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Tong Wang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Ai-Li Sheng
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhen-Ge Luo
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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376
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Abstract
Conservation of normal cognitive functions relies on the proper performance of the nervous system at the cellular and molecular level. The mammalian nicotinamide-adenine dinucleotide-dependent deacetylase SIRT1 impacts different processes potentially involved in the maintenance of brain integrity, such as chromatin remodeling, DNA repair, cell survival, and neurogenesis. Here we show that SIRT1 is expressed in neurons of the hippocampus, a key structure in learning and memory. Using a combination of behavioral and electrophysiological paradigms, we analyzed the effects of SIRT1 deficiency and overexpression on mouse learning and memory as well as on synaptic plasticity. We demonstrated that the absence of SIRT1 impaired cognitive abilities, including immediate memory, classical conditioning, and spatial learning. In addition, we found that the cognitive deficits in SIRT1 knock-out (KO) mice were associated with defects in synaptic plasticity without alterations in basal synaptic transmission or NMDA receptor function. Brains of SIRT1-KO mice exhibited normal morphology and dendritic spine structure but displayed a decrease in dendritic branching, branch length, and complexity of neuronal dendritic arbors. Also, a decrease in extracellular signal-regulated kinase 1/2 phosphorylation and altered expression of hippocampal genes involved in synaptic function, lipid metabolism, and myelination were detected in SIRT1-KO mice. In contrast, mice with high levels of SIRT1 expression in brain exhibited regular synaptic plasticity and memory. We conclude that SIRT1 is indispensable for normal learning, memory, and synaptic plasticity in mice.
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377
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Lehmann ML, Brachman RA, Listwak SJ, Herkenham M. NF-kappaB activity affects learning in aversive tasks: possible actions via modulation of the stress axis. Brain Behav Immun 2010; 24:1008-17. [PMID: 20399847 PMCID: PMC2897969 DOI: 10.1016/j.bbi.2010.04.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 04/13/2010] [Accepted: 04/13/2010] [Indexed: 12/13/2022] Open
Abstract
The role of altered activity of nuclear factor kappaB (NF-kappaB) in specific aspects of motivated behavior and learning and memory was examined in mice lacking the p50 subunit of the NF-kappaB/rel transcription factor family. Nfkb1-deficient mice are unable to produce p50 and show specific susceptibilities to infections and inflammatory challenges, but the behavioral phenotype of such mice has been largely unexamined, owing in large part to the lack of understanding of the role of NF-kappaB in nervous system function. Here we show that Nfkb1 (p50) knockout mice more rapidly learned to find the hidden platform in the Morris water maze than did wildtype mice. The rise in plasma corticosterone levels after the maze test was greater in p50 knockout than in wildtype mice. In the less stressful Barnes maze, which tests similar kinds of spatial learning, the p50 knockout mice performed similarly to control mice. Adrenalectomy with corticosterone replacement eliminated the differences between p50 knockout and wildtype mice in the water maze. Knockout mice showed increased levels of basal anxiety in the open-field and light/dark box tests, suggesting that their enhanced escape latency in the water maze was due to activation of the stress (hypothalamic-pituitary-adrenal) axis leading to elevated corticosterone production by strongly but not mildly anxiogenic stimuli. The results suggest that, as in the immune system, p50 in the nervous system normally serves to dampen NF-kappaB-mediated intracellular activities, which are manifested physiologically through elevated stress responses to aversive stimuli and behaviorally in the facilitated escape performance in learning tasks.
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Affiliation(s)
- Michael L. Lehmann
- Correspondence: Michael Lehmann, PhD., National Institute of Mental Health, 35 Convent Dr, Bldg 35, Rm 1C911, Bethesda, MD, 20892, Phone: (301) 402-3243, Fax: (301) 402-2200,
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378
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Kaufman L, Ayub M, Vincent JB. The genetic basis of non-syndromic intellectual disability: a review. J Neurodev Disord 2010; 2:182-209. [PMID: 21124998 PMCID: PMC2974911 DOI: 10.1007/s11689-010-9055-2] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Accepted: 06/25/2010] [Indexed: 11/06/2022] Open
Abstract
Intellectual disability (ID), also referred to as mental retardation (MR), is frequently the result of genetic mutation. Where ID is present together with additional clinical symptoms or physical anomalies, there is often sufficient information available for the diagnosing physician to identify a known syndrome, which may then educe the identification of the causative defect. However, where co-morbid features are absent, narrowing down a specific gene can only be done by ‘brute force’ using the latest molecular genetic techniques. Here we attempt to provide a systematic review of genetic causes of cases of ID where no other symptoms or co-morbid features are present, or non-syndromic ID. We attempt to summarize commonalities between the genes and the molecular pathways of their encoded proteins. Since ID is a common feature of autism, and conversely autistic features are frequently present in individuals with ID, we also look at possible overlaps in genetic etiology with non-syndromic ID.
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379
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Xu L, Lai D, Cheng J, Lim HJ, Keskanokwong T, Backs J, Olson EN, Wang Y. Alterations of L-type calcium current and cardiac function in CaMKII{delta} knockout mice. Circ Res 2010; 107:398-407. [PMID: 20538682 DOI: 10.1161/circresaha.110.222562] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Recent studies have highlighted important roles of CaMKII in regulating Ca(2+) handling and excitation-contraction coupling. However, the cardiac effect of chronic CaMKII inhibition has not been well understood. OBJECTIVE We have tested the alterations of L-type calcium current (I(Ca)) and cardiac function in CaMKIIdelta knockout (KO) mouse left ventricle (LV). METHODS AND RESULTS We used the patch-clamp method to record I(Ca) in ventricular myocytes and found that in KO LV, basal I(Ca) was significantly increased without changing the transmural gradient of I(Ca) distribution. Substitution of Ba(2+) for Ca(2+) showed similar increase in I(Ba). There was no change in the voltage dependence of I(Ca) activation and inactivation. I(Ca) recovery from inactivation, however, was significantly slowed. In KO LV, the Ca(2+)-dependent I(Ca) facilitation (CDF) and I(Ca) response to isoproterenol (ISO) were significantly reduced. However, ISO response was reversed by beta2-adrenergic receptor (AR) inhibition. Western blots showed a decrease in beta1-AR and an increase in Ca(v)1.2, beta2-AR, and Galphai3 protein levels. Ca(2+) transient and sarcomere shortening in KO myocytes were unchanged at 1-Hz but reduced at 3-Hz stimulation. Echocardiography in conscious mice revealed an increased basal contractility in KO mice. However, cardiac reserve to work load and beta-adrenergic stimulation was reduced. Surprisingly, KO mice showed a reduced heart rate in response to work load or beta-adrenergic stimulation. CONCLUSIONS Our results implicate physiological CaMKII activity in maintaining normal I(Ca), Ca(2+) handling, excitation-contraction coupling, and the in vivo heart function in response to cardiac stress.
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Affiliation(s)
- Lin Xu
- Department of Pediatrics and Children's Healthcare of Atlanta, Emory University, GA, USA
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380
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Smedlund K, Tano JY, Vazquez G. The Constitutive Function of Native TRPC3 Channels Modulates Vascular Cell Adhesion Molecule-1 Expression in Coronary Endothelial Cells Through Nuclear Factor κB Signaling. Circ Res 2010; 106:1479-88. [DOI: 10.1161/circresaha.109.213314] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rationale
:
Upregulation of endothelial vascular cell adhesion molecule (VCAM)-1 and the subsequent increase in monocyte recruitment constitute critical events in atherogenesis. We have recently shown that in human coronary artery endothelial cells (HCAECs) regulated expression of VCAM-1 depends, to a significant extent, on expression and function of the Ca
2+
-permeable channel transient receptor potential canonical (TRPC)3, regardless of the ability of the stimulatory signal to induce regulated Ca
2+
influx, leading to the hypothesis that TRPC3 constitutive, rather than regulated function, contributes to the underlying signaling mechanism.
Objective
:
The present studies addressed this important question and gathered mechanistic insight on the signaling coupling constitutive TRPC3 function to VCAM-1 expression.
Methods and Results
:
In HCAECs, maneuvers that prevent Ca
2+
influx or knockdown of TRPC3 markedly reduced tumor necrosis factor (TNF)α-induced VCAM-1 and monocyte adhesion. TNFα also induced TRPC3 expression and TRPC3-mediated constitutive cation influx and currents. Stable (HEK293 cells) or transient (HCAECs) overexpression of TRPC3 enhanced TNFα-induced VCAM-1 compared to wild-type cells. IκBα phosphorylation/degradation was reduced by TRPC3 knockdown and increased by channel overexpression. Inhibition of calmodulin completely prevented nuclear factor κB activation, whereas blocking calmodulin-dependent kinases or NADPH oxidases rendered partial inhibition.
Conclusions
:
Our findings indicate that in HCAECs expression of VCAM-1 and monocyte adhesion depend, to a significant extent, on TRPC3 constitutive function through a signaling mechanism that requires constitutive TRPC3-mediated Ca
2+
influx for proper activation of nuclear factor κB, presumably through Ca
2+
-dependent activation of the calmodulin/calmodulin-dependent kinase axis.
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Affiliation(s)
- Kathryn Smedlund
- From the Department of Physiology and Pharmacology (K.S., J.-Y.T., G.V.) and Center for Diabetes and Endocrine Research (G.V.), University of Toledo College of Medicine, Ohio
| | - Jean-Yves Tano
- From the Department of Physiology and Pharmacology (K.S., J.-Y.T., G.V.) and Center for Diabetes and Endocrine Research (G.V.), University of Toledo College of Medicine, Ohio
| | - Guillermo Vazquez
- From the Department of Physiology and Pharmacology (K.S., J.-Y.T., G.V.) and Center for Diabetes and Endocrine Research (G.V.), University of Toledo College of Medicine, Ohio
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381
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Muriach M, López-Pedrajas R, Barcia JM, Sanchez-Villarejo MV, Almansa I, Romero FJ. Cocaine causes memory and learning impairments in rats: involvement of nuclear factor kappa B and oxidative stress, and prevention by topiramate. J Neurochem 2010; 114:675-84. [PMID: 20477932 DOI: 10.1111/j.1471-4159.2010.06794.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Different mechanisms have been suggested for cocaine toxicity including an increase in oxidative stress but the association between oxidative status in the brain and cocaine induced-behaviour is poorly understood. Nuclear factor kappa B (NFkappaB) is a sensor of oxidative stress and participates in memory formation that could be involved in drug toxicity and addiction mechanisms. Therefore NFkappaB activity, oxidative stress, neuronal nitric oxide synthase (nNOS) activity, spatial learning and memory as well as the effect of topiramate, a previously proposed therapy for cocaine addiction, were evaluated in an experimental model of cocaine administration in rats. NFkappaB activity was decreased in the frontal cortex of cocaine treated rats, as well as GSH concentration and glutathione peroxidase activity in the hippocampus, whereas nNOS activity in the hippocampus was increased. Memory retrieval of experiences acquired prior to cocaine administration was impaired and negatively correlated with NFkappaB activity in the frontal cortex. In contrast, learning of new tasks was enhanced and correlated with the increase of nNOS activity and the decrease of glutathione peroxidase. These results provide evidence for a possible mechanistic role of oxidative and nitrosative stress and NFkappaB in the alterations induced by cocaine. Topiramate prevented all the alterations observed, showing novel neuroprotective properties.
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Affiliation(s)
- María Muriach
- Department of Physiology, Pharmacology and Toxicology, Instituto sobre Drogas y Conductas Adictivas (IDYCA), University CEU Cardenal Herrera, Valencia, Spain
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382
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De Viti S, Martino A, Musilli M, Fiorentini C, Diana G. The Rho GTPase activating CNF1 improves associative working memory for object-in-place. Behav Brain Res 2010; 212:78-83. [PMID: 20362628 DOI: 10.1016/j.bbr.2010.03.049] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 03/23/2010] [Accepted: 03/26/2010] [Indexed: 10/19/2022]
Abstract
Cerebral Rho GTPases are crucially involved in cognitive abilities. This activity is thought to be related to the regulation of actin polymerization and, thereby, of the shape of the dendritic tree. Here we report that Cytotoxic Necrotizing Factor 1 (CNF1, 1fmol/kgicv), a bacterial protein endowed with Rho GTPase activating properties, enhances working memory for object location/discrimination in C57BL/6 mice. CNF1 selectively increased the exploration of a specific familiar object moved to a position that had been previously occupied by another familiar object. Conversely, the treatment left unaffected (i) exploration of a familiar object moved to a location that was previously unoccupied and (ii) exploration of a novel object. The effects were associated with changes in Rho GTPase status, since CNF1 C866S, a recombinant CNF1 in which the enzymatic activity was abolished through substitution of serine to cysteine at position 866, was ineffective in all the experiments. The study suggests that working memory for specific object-location associations critically depends on neural connectivity. It also confirms the therapeutic potential of the manipulation of Rho GTPase signaling in the modulation of memory processes.
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Affiliation(s)
- Silvia De Viti
- Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Roma, Italy
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383
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Emmanouil M, Taoufik E, Tseveleki V, Vamvakas SS, Tselios T, Karin M, Lassmann H, Probert L. Neuronal I kappa B kinase beta protects mice from autoimmune encephalomyelitis by mediating neuroprotective and immunosuppressive effects in the central nervous system. THE JOURNAL OF IMMUNOLOGY 2010; 183:7877-89. [PMID: 20007573 DOI: 10.4049/jimmunol.0900834] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Some aspects of CNS-directed autoimmunity in multiple sclerosis are modeled in mice by immunization with myelin Ags where tissue damage is driven by myelin-reactive Th1 and Th17 effector lymphocytes. Whether the CNS plays an active role in controlling such autoimmune diseases is unknown. We used mice in which IkappaB kinase beta was deleted from Ca(2+)/calmodulin-dependent kinase IIalpha-expressing neurons (nIKKbetaKO) to investigate the contribution of neuronal NF-kappaB to the development of myelin oligodendrocyte glycoprotein 35-55-induced experimental autoimmune encephalomyelitis. We show that nIKKbetaKO mice developed a severe, nonresolving disease with increased axon loss compared with controls and this was associated with significantly reduced CNS production of neuroprotective factors (vascular endothelial growth factor, CSF1-R, and FLIP) and increased production of proinflammatory cytokines (IL-6, TNF, IL-12, IL-17, and CD30L) and chemokines. The isolation of CNS-infiltrating monocytes revealed greater numbers of CD4(+) T cells, reduced numbers of NK1.1(+) cells, and a selective accumulation of Th1 cells in nIKKbetaKO CNS from early in the disease. Our results show that neurons play an important role in determining the quality and outcome of CNS immune responses, specifically that neuronal IkappaB kinase beta is required for neuroprotection, suppression of inflammation, limitation of Th1 lymphocyte accumulation, and enhancement of NK cell recruitment in experimental autoimmune encephalomyelitis-affected CNS and stress the importance of neuroprotective strategies for the treatment of multiple sclerosis.
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Affiliation(s)
- Mary Emmanouil
- Laboratory of Molecular Genetics, Hellenic Pasteur Institute, Athens, Greece
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384
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Jang PG, Namkoong C, Kang GM, Hur MW, Kim SW, Kim GH, Kang Y, Jeon MJ, Kim EH, Lee MS, Karin M, Baik JH, Park JY, Lee KU, Kim YB, Kim MS. NF-kappaB activation in hypothalamic pro-opiomelanocortin neurons is essential in illness- and leptin-induced anorexia. J Biol Chem 2010; 285:9706-9715. [PMID: 20097762 DOI: 10.1074/jbc.m109.070706] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Anorexia and weight loss are prevalent in infectious diseases. To investigate the molecular mechanisms underlying these phenomena, we established animal models of infection-associated anorexia by administrating bacterial and viral products, lipopolysaccharide (LPS) and human immunodeficiency virus-1 transactivator protein (Tat). In these models, we found that the nuclear factor-kappaB (NF-kappaB), a pivotal transcription factor for inflammation-related proteins, was activated in the hypothalamus. In parallel, administration of LPS and Tat increased hypothalamic pro-inflammatory cytokine production, which was abrogated by inhibition of hypothalamic NF-kappaB. In vitro, NF-kappaB activation directly stimulated the transcriptional activity of pro-opiomelanocortin (POMC), a precursor of anorexigenic melanocortin, and mediated the stimulatory effects of LPS, Tat, and pro-inflammatory cytokines on POMC transcription, implying the involvement of NF-kappaB in controlling feeding behavior. Consistently, hypothalamic injection of LPS and Tat caused a significant reduction in food intake and body weight, which was prevented by blockade of NF-kappaB and melanocortin. Furthermore, disruption of I kappaB kinase-beta, an upstream kinase of NF-kappaB, in POMC neurons attenuated LPS- and Tat-induced anorexia. These findings suggest that infection-associated anorexia and weight loss are mediated via NF-kappaB activation in hypothalamic POMC neurons. In addition, hypothalamic NF-kappaB was activated by leptin, an important anorexigenic hormone, and mediates leptin-stimulated POMC transcription, indicating that hypothalamic NF-kappaB also serves as a downstream signaling pathway of leptin.
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Affiliation(s)
- Pil-Geum Jang
- Asan Institute for Life Sciences, Seoul 138-736, Korea
| | | | | | - Man-Wook Hur
- Department of Biochemistry and Molecular Biology, Yonsei University School of Medicine, Seoul 120-752, Korea
| | - Seung-Whan Kim
- Department of Pharmacology, University of Ulsan College of Medicine, Seoul 138-736, Korea
| | - Geun Hyang Kim
- Department of Pharmacology, University of Ulsan College of Medicine, Seoul 138-736, Korea
| | | | - Min-Jae Jeon
- Asan Institute for Life Sciences, Seoul 138-736, Korea
| | - Eun Hee Kim
- Department of Internal Medicine, Seoul 138-736, Korea
| | - Myung-Shik Lee
- Department of Medicine, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea
| | - Michael Karin
- Department of Pharmacology, School of Medicine, University of California San Diego, La Jolla, California 92093
| | - Ja-Hyun Baik
- School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea
| | | | - Ki-Up Lee
- Department of Internal Medicine, Seoul 138-736, Korea
| | - Young-Bum Kim
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215
| | - Min-Seon Kim
- Department of Internal Medicine, Seoul 138-736, Korea.
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385
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Abstract
Consolidation of synaptic plasticity seems to require transcription, but how the nucleus is informed in this context remains unknown. As NMDA receptor antagonists have been shown to interfere with action potential generation, the issue of whether or not a synaptically generated signal is required for nuclear signaling is currently unresolved. Here, we show that pharmacological maintenance of action potentials during NMDA receptor blockade allows for NMDA receptor-independent transcription factor binding and arc gene expression, both of which were previously thought to be NMDA receptor dependent. These data suggest that types of signaling in the nucleus previously attributed to NMDA-receptor-dependent synapse-to-nucleus signals can be initiated in the absence of NMDA receptor-dependent synaptic plasticity.
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386
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387
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Ito HT, Schuman EM. Distance-dependent homeostatic synaptic scaling mediated by a-type potassium channels. Front Cell Neurosci 2009; 3:15. [PMID: 20076774 PMCID: PMC2806179 DOI: 10.3389/neuro.03.015.2009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 11/09/2009] [Indexed: 11/13/2022] Open
Abstract
Many lines of evidence suggest that the efficacy of synapses on CA1 pyramidal neuron dendrites increases as a function of distance from the cell body. The strength of an individual synapse is also dynamically modulated by activity-dependent synaptic plasticity, which raises the question as to how a neuron can reconcile individual synaptic changes with the maintenance of the proximal-to-distal gradient of synaptic strength along the dendrites. As the density of A-type potassium channels exhibits a similar gradient from proximal (low)-to-distal (high) dendrites, the A-current may play a role in coordinating local synaptic changes with the global synaptic strength gradient. Here we describe a form of homeostatic plasticity elicited by conventional activity blockade (with tetrodotoxin) coupled with a block of the A-type potassium channel. Following A-type potassium channel inhibition for 12 h, recordings from CA1 somata revealed a significantly higher miniature excitatory postsynaptic current (mEPSC) frequency, whereas in dendritic recordings, there was no change in mEPSC frequency. Consistent with mEPSC recordings, we observed a significant increase in AMPA receptor density in stratum pyramidale but not stratum radiatum. Based on these data, we propose that the differential distribution of A-type potassium channels along the apical dendrites may create a proximal-to-distal membrane potential gradient. This gradient may regulate AMPA receptor distribution along the same axis. Taken together, our results indicate that A-type potassium channels play an important role in controlling synaptic strength along the dendrites, which may help to maintain the computational capacity of the neuron.
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Affiliation(s)
- Hiroshi T Ito
- Division of Biology, California Institute of Technology Pasadena, CA, USA
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388
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Gladding CM, Fitzjohn SM, Molnár E. Metabotropic glutamate receptor-mediated long-term depression: molecular mechanisms. Pharmacol Rev 2009; 61:395-412. [PMID: 19926678 DOI: 10.1124/pr.109.001735] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ability to modify synaptic transmission between neurons is a fundamental process of the nervous system that is involved in development, learning, and disease. Thus, synaptic plasticity is the ability to bidirectionally modify transmission, where long-term potentiation and long-term depression (LTD) represent the best characterized forms of plasticity. In the hippocampus, two main forms of LTD coexist that are mediated by activation of either N-methyl-d-aspartic acid receptors (NMDARs) or metabotropic glutamate receptors (mGluRs). Compared with NMDAR-LTD, mGluR-LTD is less well understood, but recent advances have started to delineate the underlying mechanisms. mGluR-LTD at CA3:CA1 synapses in the hippocampus can be induced either by synaptic stimulation or by bath application of the group I selective agonist (R,S)-3,5-dihydroxyphenylglycine. Multiple signaling mechanisms have been implicated in mGluR-LTD, illustrating the complexity of this form of plasticity. This review provides an overview of recent studies investigating the molecular mechanisms underlying hippocampal mGluR-LTD. It highlights the role of key molecular components and signaling pathways that are involved in the induction and expression of mGluR-LTD and considers how the different signaling pathways may work together to elicit a persistent reduction in synaptic transmission.
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Affiliation(s)
- Clare M Gladding
- MRC Centre for Synaptic Plasticity, Department of Anatomy, University of Bristol, School of Medical Sciences, University Walk, Bristol, BS8 1TD, UK
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389
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Abstract
The transcription factor NF-kappaB has diverse functions in the nervous system, depending on the cellular context. NF-kappaB is constitutively activated in glutamatergic neurons. Knockout of p65 or inhibition of neuronal NF-kappaB by super-repressor IkappaB resulted in the loss of neuroprotection and defects in learning and memory. Similarly, p50-/- mice have a lower learning ability and are sensitive to neurotoxins. Activated NF-kappaB can be transported retrogradely from activated synapses to the nucleus to translate short-term processes to long-term changes such as axon growth, which is important for long-term memory. In glia, NF-kappaB is inducible and regulates inflammatory processes that exacerbate diseases such as autoimmune encephalomyelitis, ischemia, and Alzheimer's disease. In summary, inhibition of NF-kappaB in glia might ameliorate disease, whereas activation in neurons might enhance memory. This review focuses on results produced by the analysis of genetic models.
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Affiliation(s)
- Barbara Kaltschmidt
- Molecular Neurobiology, University of Bielefeld, Universitätsstr. 25, D-33501 Bielefeld.
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390
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Corredor RG, Goldberg JL. Electrical activity enhances neuronal survival and regeneration. J Neural Eng 2009; 6:055001. [DOI: 10.1088/1741-2560/6/5/055001] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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391
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Lai KO, Ip NY. Recent advances in understanding the roles of Cdk5 in synaptic plasticity. Biochim Biophys Acta Mol Basis Dis 2009; 1792:741-5. [DOI: 10.1016/j.bbadis.2009.05.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2008] [Revised: 05/03/2009] [Accepted: 05/05/2009] [Indexed: 01/05/2023]
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392
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Wall EA, Zavzavadjian JR, Chang MS, Randhawa B, Zhu X, Hsueh RC, Liu J, Driver A, Bao XR, Sternweis PC, Simon MI, Fraser IDC. Suppression of LPS-induced TNF-alpha production in macrophages by cAMP is mediated by PKA-AKAP95-p105. Sci Signal 2009; 2:ra28. [PMID: 19531803 DOI: 10.1126/scisignal.2000202] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The activation of macrophages through Toll-like receptor (TLR) pathways leads to the production of a broad array of cytokines and mediators that coordinate the immune response. The inflammatory potential of this response can be reduced by compounds, such as prostaglandin E(2), that induce the production of cyclic adenosine monophosphate (cAMP). Through experiments with cAMP analogs and multigene RNA interference (RNAi), we showed that key anti-inflammatory effects of cAMP were mediated specifically by cAMP-dependent protein kinase (PKA). Selective inhibitors of PKA anchoring, time-lapse microscopy, and RNAi screening suggested that differential mechanisms of PKA action existed. We showed a specific role for A kinase-anchoring protein 95 in suppressing the expression of the gene encoding tumor necrosis factor-alpha, which involved phosphorylation of p105 (also known as Nfkb1) by PKA at a site adjacent to the region targeted by inhibitor of nuclear factor kappaB kinases. These data suggest that crosstalk between the TLR4 and cAMP pathways in macrophages can be coordinated through PKA-dependent scaffolds that localize specific pools of the kinase to distinct substrates.
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Affiliation(s)
- Estelle A Wall
- Alliance for Cellular Signaling, Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
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393
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Jordan BA, Kreutz MR. Nucleocytoplasmic protein shuttling: the direct route in synapse-to-nucleus signaling. Trends Neurosci 2009; 32:392-401. [PMID: 19524307 DOI: 10.1016/j.tins.2009.04.001] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2008] [Revised: 04/16/2009] [Accepted: 04/24/2009] [Indexed: 02/06/2023]
Abstract
In neurons multiple signaling pathways converge in the nucleus to regulate the expression of genes associated with long-term structural changes of synapto-dendritic input. Of pivotal importance for this type of transcriptional regulation is synapse-to-nucleus communication. Several studies suggest that the nuclear transport of proteins from synapses is involved in this signaling process, including evidence that synapses contain proteins with nuclear localization sequences and components of the nuclear import machinery. Here, we review the evidence for synapse-to-nucleus signaling by means of retrograde transport of proteins from distal processes. We discuss the mechanisms involved in their translocation and their role in the control of nuclear gene expression. Finally, we summarize the current thinking regarding the functional implications of nuclear signaling and address open questions in this evolving area of neuroscience.
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Affiliation(s)
- Bryen A Jordan
- Albert Einstein College of Medicine, Dominick P. Purpura Department of Neuroscience, Bronx, NY 10461, USA
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394
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Liebau S, Proepper C, Schmidt T, Schoen M, Bockmann J, Boeckers TM. ProSAPiP2, a novel postsynaptic density protein that interacts with ProSAP2/Shank3. Biochem Biophys Res Commun 2009; 385:460-5. [PMID: 19481056 DOI: 10.1016/j.bbrc.2009.05.098] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Accepted: 05/20/2009] [Indexed: 11/26/2022]
Abstract
The postsynaptic density (PSD) is a highly specialized structure that is located juxtaposed to the presynaptic active zone of excitatory synapses. It is composed of a variety of proteins that include receptors, signaling molecules, cytoskeletal components and scaffolding proteins. ProSAP/Shank proteins are large multidomain proteins that facilitate multiple functions within the PSD. They build large scaffolds that are the structural basis for the direct and/or indirect connection between receptor proteins and the actin based cytoskeleton. Here, we characterize a novel interaction partner of ProSAP2/Shank3, named ProSAP interacting protein 2 (ProSAPiP2) that does not show any close homology to other known proteins. It binds to the PDZ domain of ProSAP2/Shank3 and is highly expressed in the neuronal system. ProSAPiP2 is located in dendrites and spines, is enriched in the PSD and interacts with actin. Therefore ProSAPiP2 could be involved in the linkage between molecules of the PSD and the cytoskeleton.
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Affiliation(s)
- Stefan Liebau
- Institute of Anatomy and Cell Biology, Albert Einstein Allee 11, 89081 Ulm, Germany
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395
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Mao XR, Moerman-Herzog AM, Chen Y, Barger SW. Unique aspects of transcriptional regulation in neurons--nuances in NFkappaB and Sp1-related factors. J Neuroinflammation 2009; 6:16. [PMID: 19450264 PMCID: PMC2693111 DOI: 10.1186/1742-2094-6-16] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Accepted: 05/18/2009] [Indexed: 12/11/2022] Open
Abstract
The unique physiology and function of neurons create differences in their cellular physiology, including their regulation of gene expression. We began several years ago exploring the relationships between the NFκB transcription factor, neuronal survival, and glutamate receptor activation in telencephalic neurons. These studies led us to conclude that this population of cells is nearly incapable of activating the NFκB that is nonetheless expressed at reasonable levels. A subset of the κB cis elements are instead bound by members of the Sp1 family in neurons. Also surprising was our discovery that Sp1 itself, typically described as ubiquitous, is severely restricted in expression within forebrain neurons; Sp4 seems to be substituted during neuronal differentiation. These findings and their implications for neuronal differentiation – as well as potential dedifferentiation during degenerative processes – are discussed here.
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Affiliation(s)
- Xianrong R Mao
- Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA.
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396
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Abstract
Although chronic cocaine-induced changes in dendritic spines on nucleus accumbens (NAc) neurons have been correlated with behavioral sensitization, the molecular pathways governing these structural changes, and their resulting behavioral effects, are poorly understood. The transcription factor, nuclear factor kappa B (NFkappaB), is rapidly activated by diverse stimuli and regulates expression of many genes known to maintain cell structure. Therefore, we evaluated the role of NFkappaB in regulating cocaine-induced dendritic spine changes on medium spiny neurons of the NAc and the rewarding effects of cocaine. We show that chronic cocaine induces NFkappaB-dependent transcription in the NAc of NFkappaB-Lac transgenic mice. This induction of NFkappaB activity is accompanied by increased expression of several NFkappaB genes, the promoters of which show chromatin modifications after chronic cocaine exposure consistent with their transcriptional activation. To study the functional significance of this induction, we used viral-mediated gene transfer to express either a constitutively active or dominant-negative mutant of Inhibitor of kappa B kinase (IKKca or IKKdn), which normally activates NFkappaB signaling, in the NAc. We found that activation of NFkappaB by IKKca increases the number of dendritic spines on NAc neurons, whereas inhibition of NFkappaB by IKKdn decreases basal dendritic spine number and blocks the increase in dendritic spines after chronic cocaine. Moreover, inhibition of NFkappaB blocks the rewarding effects of cocaine and the ability of previous cocaine exposure to increase an animal's preference for cocaine. Together, these studies establish a direct role for NFkappaB pathways in the NAc to regulate structural and behavioral plasticity to cocaine.
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397
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The Parkinson disease protein leucine-rich repeat kinase 2 transduces death signals via Fas-associated protein with death domain and caspase-8 in a cellular model of neurodegeneration. J Neurosci 2009; 29:1011-6. [PMID: 19176810 DOI: 10.1523/jneurosci.5175-08.2009] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neurodegenerative illnesses such as Parkinson and Alzheimer disease are an increasingly prevalent problem in aging societies, yet no therapies exist that retard or prevent neurodegeneration. Dominant missense mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common genetic cause of Parkinson disease (PD), but the mechanisms by which mutant forms of LRRK2 disrupt neuronal function and cause cell death remain poorly understood. We report that LRRK2 interacts with the death adaptor Fas-associated protein with death domain (FADD), and that in primary neuronal culture LRRK2-mediated neurodegeneration is prevented by the functional inhibition of FADD or depletion of caspase-8, two key elements of the extrinsic cell death pathway. This pathway is activated by disease-triggering mutations, which enhance the LRRK2-FADD association and the consequent recruitment and activation of caspase-8. These results establish a direct molecular link between a mutant PD gene and the activation of programmed cell death signaling, and suggest that FADD/caspase-8 signaling contributes to LRRK2-induced neuronal death.
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398
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Sarnico I, Lanzillotta A, Boroni F, Benarese M, Alghisi M, Schwaninger M, Inta I, Battistin L, Spano P, Pizzi M. NF-kappaB p50/RelA and c-Rel-containing dimers: opposite regulators of neuron vulnerability to ischaemia. J Neurochem 2009; 108:475-85. [PMID: 19094066 DOI: 10.1111/j.1471-4159.2008.05783.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Diverse nuclear factor-kappaB subunits mediate opposite effects of extracellular signals on neuron survival. While RelA is activated by neurotoxic agents, c-Rel drives neuroprotective effects. In brain ischaemia RelA and p50 factors rapidly activate, but how they associate with c-Rel to form active dimers and contribute to the changes in diverse dimer activation for neuron susceptibility is unknown. We show that in both cortical neurons exposed to oxygen glucose deprivation (OGD) and mice subjected to brain ischaemia, activation of p50/RelA was associated with inhibition of c-Rel/RelA dimer and no change p50/c-Rel. Targeting c-Rel and RelA expression revealed that c-Rel dimers reduced while p50/RelA enhanced neuronal susceptibility to anoxia. Activation of p50/RelA complex is known to induce the pro-apoptotic Bim and Noxa genes. We now show that c-Rel-containing dimers, p50/c-Rel and RelA/c-Rel, but not p50/RelA, promoted Bcl-xL transcription. Accordingly, the OGD exposure induced Bim, but reduced Bcl-xL promoter activity and decreased the content of endogenous Bcl-xL protein. These findings demonstrate that within the same neuronal cell, the balance between activation of p50/RelA and c-Rel-containing complexes fine tunes the threshold of neuron vulnerability to the ischaemic insult. Selective targeting of different dimers will unravel new approaches to limit ischaemia-associated apoptosis.
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Affiliation(s)
- Ilenia Sarnico
- Division of Pharmacology and Experimental Therapeutics, Department of Biomedical Sciences & Biotechnologies, School of Medicine, University of Brescia, Viale Europa 11, Brescia, Italy
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399
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Osorio-Fuentealba C, Valdés JA, Riquelme D, Hidalgo J, Hidalgo C, Carrasco MA. Hypoxia stimulates via separate pathways ERK phosphorylation and NF-κB activation in skeletal muscle cells in primary culture. J Appl Physiol (1985) 2009; 106:1301-10. [DOI: 10.1152/japplphysiol.91224.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mammalian cells sense oxygen levels and respond to hypoxic conditions through the regulation of multiple signaling pathways and transcription factors. Here, we investigated the effects of hypoxia on the activity of two transcriptional regulators, ERK1/2 and NF-κB, in skeletal muscle cells in primary culture. We found that hypoxia significantly enhanced ERK1/2 phosphorylation and that it stimulated NF-κB-dependent gene transcription as well as nuclear translocation of a green fluorescent protein-labeled p65 NF-κB isoform. Phosphorylation of ERK1/2- and NF-κB-dependent transcription by hypoxia required calcium entry through L-type calcium channels. Calcium release from ryanodine-sensitive stores was also necessary for ERK1/2 activation but not for NF-κB-dependent-transcription. N-acetylcysteine, a general scavenger of reactive oxygen species, blocked hypoxia-induced ROS generation but did not affect the stimulation of ERK1/2 phosphorylation induced by hypoxia. In contrast, NF-κB activation was significantly inhibited by N-acetylcysteine and did not depend on ERK1/2 stimulation, as shown by the lack of effect of the upstream ERK inhibitor U-0126. These separate pathways of activation of ERK1/2 and NF-κB by hypoxia may contribute to muscle adaptation in response to hypoxic conditions.
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400
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Singh MV, Kapoun A, Higgins L, Kutschke W, Thurman JM, Zhang R, Singh M, Yang J, Guan X, Lowe JS, Weiss RM, Zimmermann K, Yull FE, Blackwell TS, Mohler PJ, Anderson ME. Ca2+/calmodulin-dependent kinase II triggers cell membrane injury by inducing complement factor B gene expression in the mouse heart. J Clin Invest 2009; 119:986-96. [PMID: 19273909 DOI: 10.1172/jci35814] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 01/21/2009] [Indexed: 01/04/2023] Open
Abstract
Myocardial Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibition improves cardiac function following myocardial infarction (MI), but the CaMKII-dependent pathways that participate in myocardial stress responses are incompletely understood. To address this issue, we sought to determine the transcriptional consequences of myocardial CaMKII inhibition after MI. We performed gene expression profiling in mouse hearts with cardiomyocyte-delimited transgenic expression of either a CaMKII inhibitory peptide (AC3-I) or a scrambled control peptide (AC3-C) following MI. Of the 8,600 mRNAs examined, 156 were substantially modulated by MI, and nearly half of these showed markedly altered responses to MI with CaMKII inhibition. CaMKII inhibition substantially reduced the MI-triggered upregulation of a constellation of proinflammatory genes. We studied 1 of these proinflammatory genes, complement factor B (Cfb), in detail, because complement proteins secreted by cells other than cardiomyocytes can induce sarcolemmal injury during MI. CFB protein expression in cardiomyocytes was triggered by CaMKII activation of the NF-kappaB pathway during both MI and exposure to bacterial endotoxin. CaMKII inhibition suppressed NF-kappaB activity in vitro and in vivo and reduced Cfb expression and sarcolemmal injury. The Cfb-/- mice were partially protected from the adverse consequences of MI. Our findings demonstrate what we believe is a novel target for CaMKII in myocardial injury and suggest that CaMKII is broadly important for the genetic effects of MI in cardiomyocytes.
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Affiliation(s)
- Madhu V Singh
- Division of Cardiovascular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA.
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