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Simmons DA, Belichenko NP, Longo FM. Pharmacological Co-Activation of TrkB and TrkC Receptor Signaling Ameliorates Striatal Neuropathology and Motor Deficits in Mouse Models of Huntington's Disease. J Huntingtons Dis 2023; 12:215-239. [PMID: 37638447 DOI: 10.3233/jhd-230589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2023]
Abstract
BACKGROUND Loss of neurotrophic support in the striatum, particularly reduced brain-derived neurotrophic factor (BDNF) levels, contributes importantly to Huntington's disease (HD) pathogenesis. Another neurotrophin (NT), NT-3, is reduced in the cortex of HD patients; however, its role in HD is unknown. BDNF and NT-3 bind with high affinity to the tropomyosin receptor-kinases (Trk) B and TrkC, respectively. Targeting TrkB/TrkC may be an effective HD therapeutic strategy, as multiple links exist between their signaling pathways and HD degenerative mechanisms. We developed a small molecule ligand, LM22B-10, that activates TrkB and TrkC to promote cell survival. OBJECTIVE This study aimed to determine if upregulating TrkB/TrkC signaling with LM22B-10 would alleviate the HD phenotype in R6/2 and Q140 mice. METHODS LM22B-10 was delivered by concomitant intranasal-intraperitoneal routes to R6/2 and Q140 mice and then motor performance and striatal pathology were evaluated. RESULTS NT-3 levels, TrkB/TrkC phosphorylation, and AKT signaling were reduced in the R6/2 striatum; LM22B-10 counteracted these deficits. LM22B-10 also reduced intranuclear huntingtin aggregates, dendritic spine loss, microglial activation, and degeneration of dopamine- and cyclic AMP-regulated phosphoprotein with a molecular weight of 32 kDa (DARPP-32) and parvalbumin-containing neurons in the R6/2 and/or Q140 striatum. Moreover, both HD mouse models showed improved motor performance after LM22B-10 treatment. CONCLUSIONS These results reveal an NT-3/TrkC signaling deficiency in the striatum of R6/2 mice, support the idea that targeting TrkB/TrkC alleviates HD-related neurodegeneration and motor dysfunction, and suggest a novel, disease-modifying, multi-target strategy for treating HD.
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Affiliation(s)
- Danielle A Simmons
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Nadia P Belichenko
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Frank M Longo
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
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Brain REST/NRSF Is Not Only a Silent Repressor but Also an Active Protector. Mol Neurobiol 2016; 54:541-550. [DOI: 10.1007/s12035-015-9658-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 12/17/2015] [Indexed: 01/04/2023]
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The Transcription Repressor REST in Adult Neurons: Physiology, Pathology, and Diseases. eNeuro 2015; 2:eN-REV-0010-15. [PMID: 26465007 PMCID: PMC4596026 DOI: 10.1523/eneuro.0010-15.2015] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 06/11/2015] [Accepted: 06/18/2015] [Indexed: 12/21/2022] Open
Abstract
REST [RE1-silencing transcription factor (also called neuron-restrictive silencer factor)] is known to repress thousands of possible target genes, many of which are neuron specific. To date, REST repression has been investigated mostly in stem cells and differentiating neurons. Current evidence demonstrates its importance in adult neurons as well. Low levels of REST, which are acquired during differentiation, govern the expression of specific neuronal phenotypes. REST-dependent genes encode important targets, including transcription factors, transmitter release proteins, voltage-dependent and receptor channels, and signaling proteins. Additional neuronal properties depend on miRNAs expressed reciprocally to REST and on specific splicing factors. In adult neurons, REST levels are not always low. Increases occur during aging in healthy humans. Moreover, extensive evidence demonstrates that prolonged stimulation with various agents induces REST increases, which are associated with the repression of neuron-specific genes with appropriate, intermediate REST binding affinity. Whether neuronal increases in REST are protective or detrimental remains a subject of debate. Examples of CA1 hippocampal neuron protection upon depolarization, and of neurodegeneration upon glutamate treatment and hypoxia have been reported. REST participation in psychiatric and neurological diseases has been shown, especially in Alzheimer’s disease and Huntington’s disease, as well as epilepsy. Distinct, complex roles of the repressor in these different diseases have emerged. In conclusion, REST is certainly very important in a large number of conditions. We suggest that the conflicting results reported for the role of REST in physiology, pathology, and disease depend on its complex, direct, and indirect actions on many gene targets and on the diverse approaches used during the investigations.
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Hougland MT, Harrison BJ, Magnuson DSK, Rouchka EC, Petruska JC. The Transcriptional Response of Neurotrophins and Their Tyrosine Kinase Receptors in Lumbar Sensorimotor Circuits to Spinal Cord Contusion is Affected by Injury Severity and Survival Time. Front Physiol 2013; 3:478. [PMID: 23316162 PMCID: PMC3540763 DOI: 10.3389/fphys.2012.00478] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 12/07/2012] [Indexed: 01/19/2023] Open
Abstract
Traumatic spinal cord injury (SCI) results in changes to the anatomical, neurochemical, and physiological properties of cells in the central and peripheral nervous system. Neurotrophins, acting by binding to their cognate Trk receptors on target cell membranes, contribute to modulation of anatomical, neurochemical, and physiological properties of neurons in sensorimotor circuits in both the intact and injured spinal cord. Neurotrophin signaling is associated with many post-SCI changes including maladaptive plasticity leading to pain and autonomic dysreflexia, but also therapeutic approaches such as training-induced locomotor improvement. Here we characterize expression of mRNA for neurotrophins and Trk receptors in lumbar dorsal root ganglia (DRG) and spinal cord after two different severities of mid-thoracic injury and at 6 and 12 weeks post-SCI. There was complex regulation that differed with tissue, injury severity, and survival time, including reversals of regulation between 6 and 12 weeks, and the data suggest that natural regulation of neurotrophins in the spinal cord may continue for months after birth. Our assessments determined that a coordination of gene expression emerged at the 12-week post-SCI time point and bioinformatic analyses address possible mechanisms. These data can inform studies meant to determine the role of the neurotrophin signaling system in post-SCI function and plasticity, and studies using this signaling system as a therapeutic approach.
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Affiliation(s)
- M Tyler Hougland
- Department of Anatomical Sciences and Neurobiology, University of Louisville Louisville, KY, USA ; Laboratory of Neural Physiology and Plasticity, Kentucky Spinal Cord Injury Research Center, Department of Neurological Surgery Louisville, KY, USA
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Kim B, Kang S, Kim SJ. Differential promoter methylation and histone modification contribute to the brain specific expression of the mouse Mbu-1 gene. Mol Cells 2012; 34:433-7. [PMID: 23076708 PMCID: PMC3887793 DOI: 10.1007/s10059-012-0182-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 09/04/2012] [Accepted: 09/12/2012] [Indexed: 12/23/2022] Open
Abstract
Mbu-1 (Csrnp-3) is a mouse gene that was identified in our previous study as showing highly restricted expression to the central nervous system. In this study, to elucidate the regulatory mechanism for tissue specificity of the gene, epigenetic approaches that identify the profiles of CpG methylation, as well as histone modifications at the promoter region were conducted. Methylation-specific PCR revealed that the CpG sites in brain tissues from embryo to adult stages showed virtually no methylation (0.052-0.67%). Lung (9.0%) and pancreas (3.0%) also showed lower levels. Other tissues such as liver, kidney, and heart showed much higher methylation levels ranging from approximately 39-93%. Treatment of 5-aza-2'-deoxycytidine (5-Aza-dC) significantly decreased promoter methylation, reactivating Mbu-1 expression in NG108-15 and Neuro-2a neuronal cells. Chromatin immunoprecipitation assay revealed that 5-Aza-dC decreased levels of acetylated H3K9 and methylated H3K4, and increased methylated H3K9. This result indicates that CpG methylation converses with histone modifications in an opposing sense of regulating Mbu-1 expression.
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Affiliation(s)
- Byungtak Kim
- Department of Life Science, Dongguk University-Seoul, Seoul 100-715,
Korea
| | - Seongeun Kang
- Department of Life Science, Dongguk University-Seoul, Seoul 100-715,
Korea
| | - Sun Jung Kim
- Department of Life Science, Dongguk University-Seoul, Seoul 100-715,
Korea
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Sone K, Tsuda M, Mori N. Position-dependent effect of a neural-restrictive silencer-like element present in the promoter downstream of the SCG10-like protein gene. J Biochem 2011; 150:451-60. [DOI: 10.1093/jb/mvr077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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Ramos B, Valín A, Sun X, Gill G. Sp4-dependent repression of neurotrophin-3 limits dendritic branching. Mol Cell Neurosci 2009; 42:152-9. [PMID: 19555762 DOI: 10.1016/j.mcn.2009.06.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Revised: 06/10/2009] [Accepted: 06/12/2009] [Indexed: 01/16/2023] Open
Abstract
Regulation of neuronal gene expression is critical to establish functional connections in the mammalian nervous system. The transcription factor Sp4 regulates dendritic patterning during cerebellar granule neuron development by limiting branching and promoting activity-dependent pruning. Here, we investigate neurotrophin-3 (NT3) as a target gene important for Sp4-dependent dendritic morphogenesis. We found that Sp4 overexpression reduced NT3 promoter activity whereas knockdown of Sp4 increased NT3 promoter activity and mRNA. Moreover, Sp4 bound to the NT3 promoter in vivo, supporting a direct role for Sp4 as a repressor of NT3 expression. Addition of exogenous NT3 promoted dendritic branching in cerebellar granule neurons. Furthermore, sequestering NT3 blocked the continued addition of dendritic branches observed upon Sp4 knockdown, but had no effect on dendrite pruning. These findings demonstrate that, during cerebellar granule neuron development, Sp4-dependent repression of neurotrophin-3 is required to limit dendritic branching and thereby promote acquisition of the mature dendritic pattern.
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Affiliation(s)
- Belén Ramos
- Department of Anatomy and Cellular Biology, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111, USA
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NRSF downregulation induces neuronal differentiation in mouse embryonic stem cells. Differentiation 2009; 77:19-28. [DOI: 10.1016/j.diff.2008.09.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 08/12/2008] [Accepted: 09/04/2008] [Indexed: 11/17/2022]
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Berninger B, Costa MR, Koch U, Schroeder T, Sutor B, Grothe B, Götz M. Functional properties of neurons derived from in vitro reprogrammed postnatal astroglia. J Neurosci 2007; 27:8654-64. [PMID: 17687043 PMCID: PMC6672931 DOI: 10.1523/jneurosci.1615-07.2007] [Citation(s) in RCA: 289] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
With the exception of astroglia-like cells in the neurogenic niches of the telencephalic subependymal or hippocampal subgranular zone, astroglia in all other regions of the adult mouse brain do not normally generate neurons. Previous studies have shown, however, that early postnatal cortical astroglia in culture can be reprogrammed to adopt a neuronal fate after forced expression of Pax6, a transcription factor (TF) required for proper neuronal specification during embryonic corticogenesis. Here we show that also the proneural genes neurogenin-2 and Mash1 (mammalian achaete schute homolog 1) possess the ability to reprogram astroglial cells from early postnatal cerebral cortex. By means of time-lapse imaging of green fluorescent astroglia, we provide direct evidence that it is indeed cells with astroglial characteristics that give rise to neurons. Using patch-clamp recordings in culture, we show that astroglia-derived neurons acquire active conductances and are capable of firing action potentials, thus displaying hallmarks of true neurons. However, independent of the TF used for reprogramming, astroglia-derived neurons appear to mature more slowly compared with embryonic-born neurons and fail to generate a functional presynaptic output within the culturing period. However, when cocultured with embryonic cortical neurons, astroglia-derived neurons receive synaptic input, demonstrating that they are competent of establishing a functional postsynaptic compartment. Our data demonstrate that single TFs are capable of inducing a remarkable functional reprogramming of astroglia toward a truly neuronal identity.
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Affiliation(s)
- Benedikt Berninger
- Department of Physiological Genomics, Institute of Physiology, Ludwig-Maximilians University Munich, D-80336 Munich, Germany
- Institute for Stem Cell Research, National Research Center for Environment and Health, D-85764 Neuherberg, Germany, and
| | - Marcos R. Costa
- Institute for Stem Cell Research, National Research Center for Environment and Health, D-85764 Neuherberg, Germany, and
| | - Ursula Koch
- Department Biologie II, Division of Neurobiology, Ludwig-Maximilians University Munich, D-82152 Planegg-Martinsried, Germany
| | - Timm Schroeder
- Institute for Stem Cell Research, National Research Center for Environment and Health, D-85764 Neuherberg, Germany, and
| | - Bernd Sutor
- Department of Physiological Genomics, Institute of Physiology, Ludwig-Maximilians University Munich, D-80336 Munich, Germany
| | - Benedikt Grothe
- Department Biologie II, Division of Neurobiology, Ludwig-Maximilians University Munich, D-82152 Planegg-Martinsried, Germany
| | - Magdalena Götz
- Department of Physiological Genomics, Institute of Physiology, Ludwig-Maximilians University Munich, D-80336 Munich, Germany
- Institute for Stem Cell Research, National Research Center for Environment and Health, D-85764 Neuherberg, Germany, and
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Zhang C, Xuan Z, Otto S, Hover JR, McCorkle SR, Mandel G, Zhang MQ. A clustering property of highly-degenerate transcription factor binding sites in the mammalian genome. Nucleic Acids Res 2006; 34:2238-46. [PMID: 16670430 PMCID: PMC1456330 DOI: 10.1093/nar/gkl248] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Transcription factor binding sites (TFBSs) are short DNA sequences interacting with transcription factors (TFs), which regulate gene expression. Due to the relatively short length of such binding sites, it is largely unclear how the specificity of protein–DNA interaction is achieved. Here, we have performed a genome-wide analysis of TFBS-like sequences for the transcriptional repressor, RE1 Silencing Transcription Factor (REST), as well as for several other representative mammalian TFs (c-myc, p53, HNF-1 and CREB). We find a nonrandom distribution of inexact sites for these TFs, referred to as highly-degenerate TFBSs, that are enriched around the cognate binding sites. Comparisons among human, mouse and rat orthologous promoters reveal that these highly-degenerate sites are conserved significantly more than expected by random chance, suggesting their positive selection during evolution. We propose that this arrangement provides a favorable genomic landscape for functional target site selection.
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Affiliation(s)
- Chaolin Zhang
- Cold Spring Harbor Laboratory1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
- Department of Biomedical Engineering, State University of New York at Stony BrookNY 11794, USA
| | - Zhenyu Xuan
- Cold Spring Harbor Laboratory1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - Stefanie Otto
- Howard Hughes Medical Institute, Department of Neurobiology and Behavior, State University of New York at Stony BrookNY 11794, USA
| | - John R. Hover
- Howard Hughes Medical Institute, Department of Neurobiology and Behavior, State University of New York at Stony BrookNY 11794, USA
| | - Sean R. McCorkle
- Biology Department, Brookhaven National LaboratoryUpton, NY 11973, USA
| | - Gail Mandel
- Howard Hughes Medical Institute, Department of Neurobiology and Behavior, State University of New York at Stony BrookNY 11794, USA
| | - Michael Q. Zhang
- Cold Spring Harbor Laboratory1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
- To whom correspondence should be addressed. Tel: +1 516 367 8393; Fax: +1 516 367 8461;
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