Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
1.
Neurobiol Learn Mem ; 210: 107903, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38403011

RESUMEN

Formation of long-term memories requires learning-induced changes in both transcription and translation. Epitranscriptomic modifications of RNA recently emerged as critical regulators of RNA dynamics, whereby adenosine methylation (m6A) regulates translation, mRNA stability, mRNA localization, and memory formation. Prior work demonstrated a pro-memory phenotype of m6A, as loss of m6A impairs and loss of the m6A/m demethylase FTO improves memory formation. Critically, these experiments focused exclusively on aversive memory tasks and were only performed in male mice. Here we show that the task type and sex of the animal alter effects of m6A on memory, whereby FTO-depletion impaired object location memory in male mice, in contrast to the previously reported beneficial effects of FTO depletion on aversive memory. Additionally, we show that female mice have no change in performance after FTO depletion, demonstrating that sex of the mouse is a critical variable for understanding how m6A contributes to memory formation. Our study provides the first evidence for FTO regulation of non-aversive spatial memory and sexspecific effects of m6A, suggesting that identification of differentially methylated targets in each sex and task will be critical for understanding how epitranscriptomic modifications regulate memory.


Asunto(s)
Adenosina , ARN , Masculino , Femenino , Animales , Ratones , ARN Mensajero/metabolismo , Metilación , Adenosina/metabolismo , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/genética , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/metabolismo
2.
Int J Mol Sci ; 21(20)2020 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-33050279

RESUMEN

Investigation into the role of methylation of the adenosine base (m6A) of RNA has only recently begun, but it quickly became apparent that m6A is able to control and fine-tune many aspects of mRNA, from splicing to translation. The ability of m6A to regulate translation distally, away from traditional sites near the nucleus, quickly caught the eye of neuroscientists because of implications for selective protein translation at synapses. Work in the brain has demonstrated how m6A is functionally required for many neuronal functions, but two in particular are covered at length here: The role of m6A in 1) neuron development; and 2) memory formation. The purpose of this review is not to cover all data about m6A in the brain. Instead, this review will focus on connecting mechanisms of m6A function in neuron development, with m6A's known function in memory formation. We will introduce the concept of "translational priming" and discuss how current data fit into this model, then speculate how m6A-mediated translational priming during memory consolidation can regulate learning and memory locally at the synapse.


Asunto(s)
Adenosina/metabolismo , Regulación de la Expresión Génica , Memoria , ARN/metabolismo , Animales , Encéfalo/metabolismo , Epigénesis Genética , Humanos , Mamíferos , Metilación , Iniciación de la Cadena Peptídica Traduccional , ARN Mensajero/genética , ARN Mensajero/metabolismo
3.
Bioessays ; 37(6): 596-601, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25880368

RESUMEN

Histone variant exchange is a novel epigenetic regulator of cognition. We speculate that H2A.Z, a variant of canonical histone H2A, exerts unique effects on transcription during distinct stages of memory formation, ultimately acting to maintain memory of previous transcriptional states and poise genes for re-activation. Hippocampus-dependent memory formation is initiated by transient expression of memory-related genes, which support the storage of recently acquired memories. Soon after, memories undergo systems consolidation, which transfers memories from the hippocampus to the cortex for long-term storage, and requires ongoing re-activation of memory-related genes. We speculate that learning-induced H2A.Z eviction from nucleosomes initially contributes to stimulus-induced transcriptional induction needed for the initial process of memory consolidation. During systems consolidation, we speculate that delayed incorporation of H2A.Z into nucleosomes of memory-related genes in the cortex is needed to poise genes for rapid re-activation, thus supporting the long-term process of memory stabilization.


Asunto(s)
Epigénesis Genética , Histonas/fisiología , Animales , Humanos , Nucleosomas/genética , Nucleosomas/metabolismo
5.
J Physiol ; 592(4): 571-86, 2014 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-24218545

RESUMEN

The ubiquitin proteasome system is required for the rapid and precise control of protein abundance that is essential for synaptic function. USP14 is a proteasome-bound deubiquitinating enzyme that recycles ubiquitin and regulates synaptic short-term synaptic plasticity. We previously reported that loss of USP14 in ax(J) mice causes a deficit in paired pulse facilitation (PPF) at hippocampal synapses. Here we report that USP14 regulates synaptic function through a novel, deubiquitination-independent mechanism. Although PPF is usually inversely related to release probability, USP14 deficiency impairs PPF without altering basal release probability. Instead, the loss of USP14 causes a large reduction in the number of synaptic vesicles. Over-expression of a catalytically inactive form of USP14 rescues the PPF deficit and restores synaptic vesicle number, indicating that USP14 regulates presynaptic structure and function independently of its role in deubiquitination. Finally, the PPF deficit caused by loss of USP14 can be rescued by pharmacological inhibition of proteasome activity, suggesting that inappropriate protein degradation underlies the PPF impairment. Overall, we demonstrate a novel, deubiquitination-independent function for USP14 in influencing synaptic architecture and plasticity.


Asunto(s)
Región CA1 Hipocampal/metabolismo , Plasticidad Neuronal , Vesículas Sinápticas/metabolismo , Ubiquitina Tiolesterasa/metabolismo , Ubiquitinación , Animales , Región CA1 Hipocampal/citología , Región CA1 Hipocampal/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Mutación , Sinapsis/metabolismo , Sinapsis/fisiología , Transmisión Sináptica , Ubiquitina Tiolesterasa/genética
6.
Neuropsychopharmacology ; 49(8): 1285-1295, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38366138

RESUMEN

Creating long-lasting memories requires learning-induced changes in gene expression, which are impacted by epigenetic modifications of DNA and associated histone proteins. Post-translational modifications (PTMs) of histones are key regulators of transcription, with different PTMs producing unique effects on gene activity and behavior. Although recent studies implicate histone variants as novel regulators of memory, effects of PTMs on the function of histone variants are rarely considered. We previously showed that the histone variant H2A.Z suppresses memory, but it is unclear if this role is impacted by H2A.Z acetylation, a PTM that is typically associated with positive effects on transcription and memory. To answer this question, we used a mutation approach to manipulate acetylation on H2A.Z without impacting acetylation of other histone types. Specifically, we used adeno-associated virus (AAV) constructs to overexpress mutated H2A.Z.1 isoforms that either mimic acetylation (acetyl-mimic) by replacing lysines 4, 7 and 11 with glutamine (KQ), or H2A.Z.1 with impaired acetylation (acetyl-defective) by replacing the same lysines with alanine (KA). Expressing the H2A.Z.1 acetyl-mimic (H2A.Z.1KQ) improved memory under weak learning conditions, whereas expressing the acetyl-defective H2A.Z.1KA generally impaired memory, indicating that the effect of H2A.Z.1 on memory depends on its acetylation status. RNA sequencing showed that H2A.Z.1KQ and H2A.Z.1KA uniquely impact the expression of different classes of genes in both females and males. Specifically, H2A.Z.1KA preferentially impacts genes involved in synaptic function, suggesting that acetyl-defective H2A.Z.1 impairs memory by altering synaptic regulation. Finally, we describe, for the first time, that H2A.Z is also involved in alternative splicing of neuronal genes, whereby H2A.Z depletion, as well as expression of H2A.Z.1 lysine mutants influence transcription and splicing of different gene targets, suggesting that H2A.Z.1 can impact behavior through effects on both splicing and gene expression. This is the first study to demonstrate that direct manipulation of H2A.Z post-translational modifications regulates memory, whereby acetylation adds another regulatory layer by which histone variants can fine tune higher brain functions through effects on gene expression and splicing.


Asunto(s)
Empalme Alternativo , Histonas , Lisina , Memoria , Procesamiento Proteico-Postraduccional , Transcripción Genética , Histonas/metabolismo , Animales , Acetilación , Lisina/metabolismo , Memoria/fisiología , Transcripción Genética/fisiología , Masculino , Ratones , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Ratones Endogámicos C57BL , Femenino
7.
J Neurosci ; 32(19): 6600-10, 2012 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-22573682

RESUMEN

Unlike nonmammalian vertebrates, mammals cannot convert inner ear cochlear supporting cells (SCs) into sensory hair cells (HCs) after damage, thus causing permanent deafness. Here, we achieved in vivo conversion of two SC subtypes, pillar cells (PCs) and Deiters' cells (DCs), into HCs by inducing targeted expression of Atoh1 at neonatal and juvenile ages using novel mouse models. The conversion only occurred in ∼10% of PCs and DCs with ectopic Atoh1 expression and started with reactivation of endogenous Atoh1 followed by expression of 11 HC and synaptic markers, a process that took approximately 3 weeks in vivo. These new HCs resided in the outer HC region, formed stereocilia, contained mechanoelectrical transduction channels, and survived for >2 months in vivo; however, they surprisingly lacked prestin and oncomodulin expression and mature HC morphology. In contrast, adult PCs and DCs no longer responded to ectopic Atoh1 expression, even after outer HC damage. Finally, permanent Atoh1 expression in endogenous HCs did not affect prestin expression but caused cell loss of mature HCs. Together, our results demonstrate that in vivo conversion of PCs and DCs into immature HCs by Atoh1 is age dependent and resembles normal HC development. Therefore, combined expression of Atoh1 with additional factors holds therapeutic promise to convert PCs and DCs into functional HCs in vivo for regenerative purposes.


Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/biosíntesis , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Coristoma/metabolismo , Regulación del Desarrollo de la Expresión Génica , Células Ciliadas Auditivas/metabolismo , Núcleo Vestibular Lateral/metabolismo , Factores de Edad , Animales , Animales Recién Nacidos , Cóclea/citología , Cóclea/crecimiento & desarrollo , Cóclea/metabolismo , Femenino , Masculino , Ratones , Ratones Transgénicos , Núcleo Vestibular Lateral/citología , Núcleo Vestibular Lateral/crecimiento & desarrollo
8.
J Neurosci ; 32(31): 10530-40, 2012 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-22855803

RESUMEN

Sox2 plays critical roles in cell fate specification during development and in stem cell formation; however, its role in postmitotic cells is largely unknown. Sox2 is highly expressed in supporting cells (SCs) of the postnatal mammalian auditory sensory epithelium, which unlike non-mammalian vertebrates remains quiescent even after sensory hair cell damage. Here, we induced the ablation of Sox2, specifically in SCs at three different postnatal ages (neonatal, juvenile and adult) in mice. In neonatal mice, Sox2-null inner pillar cells (IPCs, a subtype of SCs) proliferated and generated daughter cells, while other SC subtypes remained quiescent. Furthermore, p27(Kip1), a cell cycle inhibitor, was absent in Sox2-null IPCs. Similarly, upon direct deletion of p27(Kip1), p27(Kip1)-null IPCs also proliferated but retained Sox2 expression. Interestingly, cell cycle control of IPCs by Sox2-mediated expression of p27(Kip1) gradually declined with age. In addition, deletion of Sox2 or p27(Kip1) did not cause a cell fate change. Finally, chromatin immunoprecipitation with Sox2 antibodies and luciferase reporter assays with the p27(Kip1) promoter support that Sox2 directly activates p27(Kip1) transcription in postmitotic IPCs. Hence, in contrast to the well known activity of Sox2 in promoting proliferation and cell fate determination, our data demonstrate that Sox2 plays a novel role as a key upstream regulator of p27(Kip1) to maintain the quiescent state of postmitotic IPCs. Our studies suggest that manipulating Sox2 or p27(Kip1) expression is an effective approach to inducing proliferation of neonatal auditory IPCs, an initial but necessary step toward restoring hearing in mammals.


Asunto(s)
Cóclea/citología , Inhibidor p27 de las Quinasas Dependientes de la Ciclina/metabolismo , Células Ciliadas Auditivas/metabolismo , Células Laberínticas de Soporte/fisiología , Factores de Transcripción SOXB1/metabolismo , Factores de Edad , Animales , Animales Recién Nacidos , Bromodesoxiuridina/metabolismo , Ciclo Celular/efectos de los fármacos , Ciclo Celular/genética , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/genética , Línea Celular Transformada , Proliferación Celular/efectos de los fármacos , Inmunoprecipitación de Cromatina , Inhibidor p27 de las Quinasas Dependientes de la Ciclina/genética , Desoxiuridina/análogos & derivados , Desoxiuridina/metabolismo , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Regulación del Desarrollo de la Expresión Génica/genética , Proteínas de Homeodominio/genética , Humanos , Etiquetado Corte-Fin in Situ , Proteínas Luminiscentes/genética , Ratones , Ratones Transgénicos , Cadenas Pesadas de Miosina/metabolismo , Receptor Tipo 3 de Factor de Crecimiento de Fibroblastos/genética , Receptor Tipo 3 de Factor de Crecimiento de Fibroblastos/metabolismo , Factores de Transcripción SOXB1/genética , Tamoxifeno/farmacología , Transfección , Proteínas Supresoras de Tumor/genética
9.
PLoS Negl Trop Dis ; 16(7): e0010600, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35857765

RESUMEN

During chronic infection, the single celled parasite, Toxoplasma gondii, can migrate to the brain where it has been associated with altered dopamine function and the capacity to modulate host behavior, increasing risk of neurocognitive disorders. Here we explore alterations in dopamine-related behavior in a new mouse model based on stimulant (cocaine)-induced hyperactivity. In combination with cocaine, infection resulted in heightened sensorimotor deficits and impairment in prepulse inhibition response, which are commonly disrupted in neuropsychiatric conditions. To identify molecular pathways in the brain affected by chronic T. gondii infection, we investigated patterns of gene expression. As expected, infection was associated with an enrichment of genes associated with general immune response pathways, that otherwise limits statistical power to identify more informative pathways. To overcome this limitation and focus on pathways of neurological relevance, we developed a novel context enrichment approach that relies on a customized ontology. Applying this approach, we identified genes that exhibited unexpected patterns of expression arising from the combination of cocaine exposure and infection. These include sets of genes which exhibited dampened response to cocaine in infected mice, suggesting a possible mechanism for some observed behaviors and a neuroprotective effect that may be advantageous to parasite persistence. This model offers a powerful new approach to dissect the molecular pathways by which T. gondii infection contributes to neurocognitive disorders.


Asunto(s)
Cocaína , Toxoplasma , Animales , Encéfalo/parasitología , Cocaína/metabolismo , Dopamina , Expresión Génica , Masculino , Ratones
10.
Commun Biol ; 5(1): 482, 2022 05 19.
Artículo en Inglés | MEDLINE | ID: mdl-35590030

RESUMEN

Histone variants H2A.Z and H3.3 are epigenetic regulators of memory, but roles of other variants are not well characterized. macroH2A (mH2A) is a structurally unique histone that contains a globular macrodomain connected to the histone region by an unstructured linker. Here we assessed if mH2A regulates memory and if this role varies for the two mH2A-encoding genes, H2afy (mH2A1) and H2afy2 (mH2A2). We show that fear memory is impaired in mH2A1, but not in mH2A2-deficient mice, whereas both groups were impaired in a non-aversive spatial memory task. However, impairment was larger for mH2A1- deficient mice, indicating a preferential role for mH2A1 over mH2A2 in memory. Accordingly, mH2A1 depletion in the mouse hippocampus resulted in more extensive transcriptional de-repression compared to mH2A2 depletion. mH2A1-depleted mice failed to induce a normal transcriptional response to fear conditioning, suggesting that mH2A1 depletion impairs memory by altering transcription. Using chromatin immunoprecipitation (ChIP) sequencing, we found that both mH2A proteins are enriched on transcriptionally repressed genes, but only mH2A1 occupancy was dynamically modified during learning, displaying reduced occupancy on upregulated genes after training. These data identify mH2A as a regulator of memory and suggest that mH2A1 supports memory by repressing spurious transcription and promoting learning-induced transcriptional activation.


Asunto(s)
Hipocampo , Histonas , Animales , Hipocampo/metabolismo , Histonas/genética , Histonas/metabolismo , Ratones
11.
eNeuro ; 8(6)2021.
Artículo en Inglés | MEDLINE | ID: mdl-34785571

RESUMEN

Adeno-associated viruses (AAVs) are a commonly used tool in neuroscience to efficiently label, trace, and/or manipulate neuronal populations. Highly specific targeting can be achieved through recombinase-dependent AAVs in combination with transgenic rodent lines that express Cre-recombinase in specific cell types. Visualization of viral expression is typically achieved through fluorescent reporter proteins (e.g., GFP or mCherry) packaged within the AAV genome. Although nonamplified fluorescence is usually sufficient to observe viral expression, immunohistochemical amplification of the fluorescent reporter is routinely used to improve viral visualization. In the present study, Cre-dependent AAVs were injected into the neocortex of wild-type C57BL/6J mice. While we observed weak but consistent nonamplified off-target double inverted open reading frame (DIO) expression in C57BL/6J mice, antibody amplification of the GFP or mCherry reporter revealed notable Cre-independent viral expression. Off-target expression of DIO constructs in wild-type C57BL/6J mice occurred independent of vendor, AAV serotype, or promoter. We also evaluated whether Cre-independent expression had functional effects via designer receptors exclusively activated by designer drugs (DREADDs). The DREADD agonist C21 (compound 21) had no effect on contextual fear conditioning or c-Fos expression in DIO-hM3Dq-mCherry+ cells of C57BL/6J mice. Together, our results indicate that DIO constructs have off-target expression in wild-type subjects. Our findings are particularly important for the design of experiments featuring sensitive systems and/or quantitative measurements that could be negatively impacted by off-target expression.


Asunto(s)
Dependovirus , Integrasas , Animales , Dependovirus/genética , Imidazoles , Integrasas/genética , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Sulfonamidas , Tiofenos
12.
Cell Rep ; 36(7): 109551, 2021 08 17.
Artículo en Inglés | MEDLINE | ID: mdl-34407406

RESUMEN

Rapid removal of histone H2A.Z from neuronal chromatin is a key step in learning-induced gene expression and memory formation, but mechanisms underlying learning-induced H2A.Z removal are unclear. Anp32e was recently identified as an H2A.Z-specific histone chaperone that removes H2A.Z from nucleosomes in dividing cells, but its role in non-dividing neurons is unclear. Moreover, prior studies investigated Anp32e function under steady-state rather than stimulus-induced conditions. Here, we show that Anp32e regulates H2A.Z binding in neurons under steady-state conditions, with lesser impact on stimulus-induced H2A.Z removal. Functionally, Anp32e depletion leads to H2A.Z-dependent impairment in transcription and dendritic arborization in cultured hippocampal neurons, as well as impaired recall of contextual fear memory and transcriptional regulation. Together, these data indicate that Anp32e regulates behavioral and morphological outcomes by preventing H2A.Z accumulation in chromatin rather than by regulating activity-mediated H2A.Z dynamics.


Asunto(s)
Dendritas/metabolismo , Chaperonas de Histonas/metabolismo , Histonas/metabolismo , Memoria , Chaperonas Moleculares/metabolismo , Neuronas/metabolismo , Transcripción Genética , Animales , Cromatina/metabolismo , Regulación de la Expresión Génica , Hipocampo/metabolismo , Masculino , Ratones Endogámicos C57BL , Unión Proteica , ARN Mensajero/genética , ARN Mensajero/metabolismo
13.
J Neurosci ; 29(35): 10909-19, 2009 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-19726649

RESUMEN

Dysfunction of the ubiquitin proteasome system (UPS) has been implicated in the pathogenesis of many neurological diseases, including Alzheimer's, spinocerebellar ataxia, and several motor neuron diseases. Recent research indicates that changes in synaptic transmission may play a critical role in the progression of neurological disease; however, the mechanisms by which the UPS regulates synaptic structure and function have not been well characterized. In this report, we show that Usp14 is indispensable for synaptic development and function at neuromuscular junctions (NMJs). Usp14-deficient axJ mice display a resting tremor, a reduction in muscle mass, and notable hindlimb rigidity without any detectable loss of motor neurons. Instead, loss of Usp14 causes developmental defects at motor neuron endplates. Presynaptic defects include phosphorylated neurofilament accumulations, nerve terminal sprouting, and poor arborization of the motor nerve terminals, whereas postsynaptic acetylcholine receptors display immature plaque-like morphology. These structural changes in the NMJ correlated with ubiquitin loss in the spinal cord and sciatic nerve. Further studies demonstrated that the greatest loss of ubiquitin was found in synaptosomal fractions, suggesting that the endplate swellings may be caused by decreased protein turnover at the synapse. Transgenic restoration of Usp14 in the nervous system corrected the levels of monomeric ubiquitin in the motor neuron circuit and the defects that were observed in the motor endplates and muscles of the axJ mice. These data define a critical role for Usp14 at mammalian synapses and suggest a requirement for local ubiquitin recycling by the proteasome to control the development and function of NMJs.


Asunto(s)
Unión Neuromuscular/enzimología , Unión Neuromuscular/crecimiento & desarrollo , Complejo de la Endopetidasa Proteasomal/metabolismo , Sinapsis/enzimología , Ubiquitina Tiolesterasa/fisiología , Ubiquitina/metabolismo , Animales , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Unión Neuromuscular/metabolismo , Ubiquitina Tiolesterasa/deficiencia
14.
Neuropsychopharmacology ; 45(6): 916-924, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-31837649

RESUMEN

The internal representation of an experience is thought to be encoded by long-lasting physical changes to the brain ("engrams") . Previously, we and others showed within the lateral amygdala (LA), a region critical for auditory conditioned fear, eligible neurons compete against one other for allocation to an engram. Neurons with relatively higher function of the transcription factor CREB were more likely to be allocated to the engram. In these studies, though, CREB function was artificially increased for several days before training. Precisely when increased CREB function is important for allocation remains an unanswered question. Here, we took advantage of a novel optogenetic tool (opto-DN-CREB) to gain spatial and temporal control of CREB function in freely behaving mice. We found increasing CREB function in a small, random population of LA principal neurons in the minutes, but not 24 h, before training was sufficient to enhance memory, likely because these neurons were preferentially allocated to the underlying engram. However, similarly increasing CREB activity in a small population of random LA neurons immediately after training disrupted subsequent memory retrieval, likely by disrupting the precise spatial and temporal patterns of offline post-training neuronal activity and/or function required for consolidation. These findings reveal the importance of the timing of CREB activity in regulating allocation and subsequent memory retrieval, and further, highlight the potential of optogenetic approaches to control protein function with temporal specificity in behaving animals.


Asunto(s)
Complejo Nuclear Basolateral , Optogenética , Animales , Miedo , Memoria , Ratones , Neuronas
15.
Sci Rep ; 10(1): 14331, 2020 08 31.
Artículo en Inglés | MEDLINE | ID: mdl-32868857

RESUMEN

Emerging evidence suggests that histone variants are novel epigenetic regulators of memory, whereby histone H2A.Z suppresses fear memory. However, it is not clear if altered fear memory can also modify risk for PTSD, and whether these effects differ in males and females. Using conditional-inducible H2A.Z knockout (cKO) mice, we showed that H2A.Z binding is higher in females and that H2A.Z cKO enhanced fear memory only in males. However, H2A.Z cKO improved memory on the non-aversive object-in-place task in both sexes, suggesting that H2A.Z suppresses non-stressful memory irrespective of sex. Given that risk for fear-related disorders, such as PTSD, is biased toward females, we examined whether H2A.Z cKO also has sex-specific effects on fear sensitization in the stress-enhanced fear learning (SEFL) model of PTSD, as well as associated changes in pain sensitivity. We found that H2A.Z cKO reduced stress-induced sensitization of fear learning and pain responses preferentially in female mice, indicating that the effects of H2A.Z depend on sex and the type of task, and are influenced by history of stress. These data suggest that H2A.Z may be a sex-specific epigenetic risk factor for PTSD susceptibility, with implications for developing sex-specific therapeutic interventions.


Asunto(s)
Miedo/fisiología , Histonas/fisiología , Memoria/fisiología , Caracteres Sexuales , Trastornos por Estrés Postraumático/fisiopatología , Animales , Aprendizaje por Asociación/fisiología , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina , Femenino , Hiperalgesia/genética , Masculino , Aprendizaje por Laberinto , Ratones Noqueados , Plasticidad Neuronal/genética
16.
eNeuro ; 5(5)2018.
Artículo en Inglés | MEDLINE | ID: mdl-30417078

RESUMEN

Memory formation is a protracted process that initially involves the hippocampus and becomes increasingly dependent on the cortex over time, but the mechanisms of this transfer are unclear. We recently showed that hippocampal depletion of the histone variant H2A.Z enhances both recent and remote memories, but the use of virally mediated depletion reduced H2A.Z levels throughout testing, making its temporally specific function unclear. Given the lack of drugs that target histone variants, we tested existing drugs for efficacy against H2A.Z based on their targeting of known H2A.Z regulators. The Tip60 (part of H2A.Z deposition complex) inhibitor Nu9056 reduced H2A.Z binding, whereas the histone deacetylase (HDAC) inhibitor Trichostatin-A increased H2A.Z acetylation without influencing total H2A.Z in cultured hippocampal neurons. Tip60 (but not HDAC) inhibition 23 h after learning enhanced remote (tested at 7 d) and not recent (tested at 24 h) contextual fear memory in mice. In contrast, Tip60 inhibition 30 d after learning impaired recall of remote memory after 1 h, but protected the memory from further decline 24 h later. These data provide the first evidence of a delayed postlearning role for histone variants in supporting memory transfer during systems consolidation.


Asunto(s)
Miedo/efectos de los fármacos , Histonas/metabolismo , Lisina Acetiltransferasa 5/metabolismo , Memoria/efectos de los fármacos , Tiazoles/farmacología , Transactivadores/metabolismo , Animales , Cognición/efectos de los fármacos , Cognición/fisiología , Miedo/fisiología , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Histona Desacetilasas/metabolismo , Histonas/genética , Masculino , Memoria/fisiología , Ratones Endogámicos C57BL , Nucleosomas/metabolismo
17.
Cell Rep ; 22(5): 1124-1131, 2018 01 30.
Artículo en Inglés | MEDLINE | ID: mdl-29386101

RESUMEN

Histone variants were recently discovered to regulate neural plasticity, with H2A.Z emerging as a memory suppressor. Using whole-genome sequencing of the mouse hippocampus, we show that basal H2A.Z occupancy is positively associated with steady-state transcription, whereas learning-induced H2A.Z removal is associated with learning-induced gene expression. AAV-mediated H2A.Z depletion enhanced fear memory and resulted in gene-specific alterations of learning-induced transcription, reinforcing the role of H2A.Z as a memory suppressor. H2A.Z accumulated with age, although it remained sensitive to learning-induced eviction. Learning-related H2A.Z removal occurred at largely distinct genes in young versus aged mice, suggesting that H2A.Z is subject to regulatory shifts in the aged brain despite similar memory performance. When combined with prior evidence of H3.3 accumulation in neurons, our data suggest that nucleosome composition in the brain is reorganized with age.


Asunto(s)
Envejecimiento/metabolismo , Hipocampo/metabolismo , Histonas/metabolismo , Aprendizaje/fisiología , Animales , Regulación de la Expresión Génica , Masculino , Ratones , Ratones Endogámicos C57BL , Nucleosomas/metabolismo
18.
Neuropsychopharmacology ; 42(7): 1502-1510, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28205605

RESUMEN

The formation of long-lasting memories requires coordinated changes in gene expression and protein synthesis. Although many studies implicate DNA modifications (DNA methylation, histone modifications) in memory formation, the contributions of RNA modifications remain largely unexplored. Here we investigated the role of mRNA methylation in hippocampal-dependent memory formation in mice. RNA modifications are highly dynamic and readily reversible. Methyltransferases add a methyl group to mRNA while demethylases remove methyl groups. Here we focused on examining the role of the best characterized RNA demethylase, FTO (fat mass and obesity-associated) in memory. We observed that FTO is expressed in the nuclei, dendrites and near dendritic spines of mouse dorsal hippocampal CA1 neurons. Next, we found that contextual fear conditioning transiently (0.5 h) decreased Fto levels in these neurons, with the largest decrease in FTO observed near synapses. The decrease in FTO observed shortly after contextual fear conditioning suggests that FTO normally constrains memory formation. To directly test this, we artificially decreased FTO levels in dorsal hippocampus of otherwise normal (wild-type) mice by microinjecting before training a single herpes simplex virus (HSV) vector expressing either CRISPR/Cas9 or shRNA targeted against Fto. Decreasing FTO using either method specifically enhanced contextual fear memory. Together, these results show the importance of FTO during memory formation and, furthermore, implicate mRNA modification and epi-transcriptomics as novel regulators of memory formation.


Asunto(s)
Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/fisiología , Región CA1 Hipocampal/metabolismo , Condicionamiento Psicológico/fisiología , Miedo/fisiología , Memoria/fisiología , ARN Mensajero/metabolismo , Animales , Miedo/psicología , Masculino , Metilación , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos C57BL
20.
Front Genet ; 6: 362, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26793235

RESUMEN

Gene editing tools are essential for uncovering how genes mediate normal brain-behavior relationships and contribute to neurodegenerative and neuropsychiatric disorders. Recent progress in gene editing technology now allows neuroscientists unprecedented access to edit the genome efficiently. Although many important tools have been developed, here we focus on approaches that allow for rapid gene editing in the adult nervous system, particularly CRISPR/Cas9 and anti-sense nucleotide-based techniques. CRISPR/Cas9 is a flexible gene editing tool, allowing the genome to be manipulated in diverse ways. For instance, CRISPR/Cas9 has been successfully used to knockout genes, knock-in mutations, overexpress or inhibit gene activity, and provide scaffolding for recruiting specific epigenetic regulators to individual genes and gene regions. Moreover, the CRISPR/Cas9 system may be modified to target multiple genes at one time, affording simultaneous inhibition and overexpression of distinct genetic targets. Although many of the more advanced applications of CRISPR/Cas9 have not been applied to the nervous system, the toolbox is widely accessible, such that it is poised to help advance neuroscience. Anti-sense nucleotide-based technologies can be used to rapidly knockdown genes in the brain. The main advantage of anti-sense based tools is their simplicity, allowing for rapid gene delivery with minimal technical expertise. Here, we describe the main applications and functions of each of these systems with an emphasis on their many potential applications in neuroscience laboratories.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA