Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 42
Filtrar
1.
Cell ; 154(3): 637-50, 2013 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-23911326

RESUMO

Synaptic plasticity induced by cocaine and other drugs underlies addiction. Here we elucidate molecular events at synapses that cause this plasticity and the resulting behavioral response to cocaine in mice. In response to D1-dopamine-receptor signaling that is induced by drug administration, the glutamate-receptor protein metabotropic glutamate receptor 5 (mGluR5) is phosphorylated by microtubule-associated protein kinase (MAPK), which we show potentiates Pin1-mediated prolyl-isomerization of mGluR5 in instances where the product of an activity-dependent gene, Homer1a, is present to enable Pin1-mGluR5 interaction. These biochemical events potentiate N-methyl-D-aspartate receptor (NMDAR)-mediated currents that underlie synaptic plasticity and cocaine-evoked motor sensitization as tested in mice with relevant mutations. The findings elucidate how a coincidence of signals from the nucleus and the synapse can render mGluR5 accessible to activation with consequences for drug-induced dopamine responses and point to depotentiation at corticostriatal synapses as a possible therapeutic target for treating addiction.


Assuntos
Transtornos Relacionados ao Uso de Cocaína/fisiopatologia , Cocaína/metabolismo , Dopamina/metabolismo , Peptidilprolil Isomerase/metabolismo , Sequência de Aminoácidos , Animais , Encéfalo/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Embrião de Mamíferos/metabolismo , Proteínas de Arcabouço Homer , Potenciação de Longa Duração , Camundongos , Dados de Sequência Molecular , Peptidilprolil Isomerase de Interação com NIMA , Fosforilação , Receptores de AMPA/metabolismo , Receptores de Dopamina D1/metabolismo , Receptores de Ácido Caínico/química , Receptores de Ácido Caínico/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Sinapses/metabolismo
2.
Cell ; 145(5): 758-72, 2011 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-21565394

RESUMO

We have created a mouse genetic model that mimics a human mutation of Shank3 that deletes the C terminus and is associated with autism. Expressed as a single copy [Shank3(+/ΔC) mice], Shank3ΔC protein interacts with the wild-type (WT) gene product and results in >90% reduction of Shank3 at synapses. This "gain-of-function" phenotype is linked to increased polyubiquitination of WT Shank3 and its redistribution into proteasomes. Similarly, the NR1 subunit of the NMDA receptor is reduced at synapses with increased polyubiquitination. Assays of postsynaptic density proteins, spine morphology, and synapse number are unchanged in Shank3(+/ΔC) mice, but the amplitude of NMDAR responses is reduced together with reduced NMDAR-dependent LTP and LTD. Reciprocally, mGluR-dependent LTD is markedly enhanced. Shank3(+/ΔC) mice show behavioral deficits suggestive of autism and reduced NMDA receptor function. These studies reveal a mechanism distinct from haploinsufficiency by which mutations of Shank3 can evoke an autism-like disorder.


Assuntos
Transtorno Autístico/genética , Proteínas de Transporte/metabolismo , Modelos Animais de Doenças , Receptores de N-Metil-D-Aspartato/metabolismo , Animais , Transtorno Autístico/metabolismo , Transtorno Autístico/fisiopatologia , Proteínas de Transporte/genética , Hipocampo/metabolismo , Humanos , Relações Interpessoais , Potenciação de Longa Duração , Depressão Sináptica de Longo Prazo , Camundongos , Proteínas dos Microfilamentos , Proteínas do Tecido Nervoso , Receptores de Glutamato Metabotrópico/metabolismo , Sinapses/metabolismo , Ubiquitinação
3.
Angew Chem Int Ed Engl ; 63(13): e202318030, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38308534

RESUMO

The specific states of aggregation of metal atoms in sub-nanometer-sized gold clusters are related to the different quantum confinement volumes of electrons, leading to novel optical and electronic properties. These volumes can be tuned by changing the relative positions of the gold atoms to generate isomers. Studying the isomeric gold core and the electron coupling between the basic units is fundamentally important for nanoelectronic devices and luminescence; however, appropriate cases are lacking. In this study, the structure of the first staggered di-superatomic Au25 -S was solved using single-crystal X-ray diffraction. The optical properties of Au25 -S were studied by comparing with eclipsed Au25 -E. From Au25 -E to Au25 -S, changes in the electronic structures occurred, resulting in significantly different optical absorptions originating from the coupling between the two Au13 modules. Au25 -S shows a longer electron decay lifetime of 307.7 ps before populating the lowest triplet emissive state, compared to 1.29 ps for Au25 -E. The experimental and theoretical results show that variations in the geometric isomerism lead to distinct photophysical processes owing to isomerism-dependent electronic coupling. This study offers new insights into the connection between the geometric isomerism of nanosized building blocks and the optical properties of their assemblies, opening new possibilities for constructing function-specific nanomaterials.

4.
J Am Chem Soc ; 145(11): 6166-6176, 2023 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-36912642

RESUMO

Superstructures made from nanoscale clusters with new collective properties are promising in high-tech applications; however, chiral superstructures remain elusive, and the limited intercluster coupling effect at room temperature hampers the tailoring of collective properties. Here, we show that from chiral monomeric copper clusters to two enantiomeric pairs of supercrystals with distinct phases, the absorption band edge red-shifts by over 1.3 eV, with photoluminescence and circularly polarized phosphorescence from visible (572 nm) to near-infrared (NIR, 858 nm). These supercrystals with high NIR quantum yields of up to 45% at room temperature are prototyped for night-vision imaging. In response to solvent and temperature stimuli, chiral supercrystal-to-supercrystal transformations occurred, concomitant with high-contrast optical/chiroptical switching. In situ single-crystal X-ray diffraction (SCXRD), steady-state and time-resolved optical spectroscopy, and response experiments combined with theoretical calculations demonstrate that distance-sensitive intercluster orbital interactions contribute to the exceptional collective optical responses. Such chiral supercrystals built from subnanoscale metal clusters with novel collective chiroptical responses would be useful in the fields of information storage and NIR optical devices.

5.
J Am Chem Soc ; 145(47): 25874-25886, 2023 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-37963217

RESUMO

Circularly polarized luminescence (CPL) materials have attracted considerable attention for their promising applications in encryption, chiral sensing, and three-dimensional (3D) displays. However, the preparation of high-efficiency, pure blue CPL materials remains challenging. In this study, we reported an enantiomeric pair of triangle copper(I) clusters (R/S-Cu3) rigidified by employing chiral N-heterocyclic carbene (NHC) ligands with two pyridine-functionalized wingtips. These chiral clusters emitted pure blue phosphorescence that overlapped with that of the commercial blue phosphor having Commission Internationale de l'Eclairage (CIE) chromaticity coordinates of (0.14, 0.10), and the films exhibited an unprecedented photoluminescence quantum yield (PLQY) of ∼70.0%. Additionally, the solutions showed very bright circularly polarized phosphorescence (CPP) with a dissymmetry factor of ±2.1 × 10-3. The excellent solubility and photostability endowed these pure-blue-emitting chiral clusters with promising applications as pure blue CPP inks for 3D printing white objects, such as precise-atomic-enlarged models of metal clusters and a lovely white stereoscopic "rabbit". The intricate mechanism underlying blue phosphorescence in this small cluster and across various states is elucidated through a comprehensive approach that integrates thorough analysis of luminescence properties, controlled experiments, and theoretical calculations. For the first time, we propose that the dominant high-energy emission center is constituted by delocalized hybrid orbitals over multiple atomic centers, encompassing both the metal and the coordinated atoms. This challenges stereotypical assumptions that the cluster center solely supports low-energy emissions. This work expands the currently limited range of CPP functional materials and provides a new direction for CPP applications involving NHC-stabilized metal clusters.

6.
J Am Chem Soc ; 144(43): 19739-19747, 2022 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-36278926

RESUMO

Understanding how the chiral or achiral section in chiral nanostructures contributes to circularly polarized light emission (CPLE) at the atomic level is of fundamental importance. Here, we report two pairs of atomically precise enantiomers of homosilver (R/S-Ag12Ag32) and heterometal (R/S-Au12Ag32) clusters. The geometrical chirality of R/S-Ag12Ag32 arises from the chiral ligand and interface consisting of positive moieties of Ag32(R/S-PS)24. The circular dichroism of R/S-Ag12Ag32 is active, but CPLE-silent. A complete metal change from Ag12 to Au12 in the achiral core section of S2-@M12@S8 engenders isomorphous heterometal R/S-Au12Ag32, which activates CPLE. We further quantify the contributions of achiral and chiral sections and for the first time unveil that heterometal bonding (Au12-Ag32) at the linkage varies the delocalization of orbitals and proportion of achiral and chiral section in electron transition-involved orbitals, thus activating CPLE. Based on these unique atomically precise homochiral metal clusters, our work provides a new insight into the contributions of achiral and chiral sections to the origin of chiroptical response of chiral metal clusters, paving the way to advance the development of CPLE nanoparticles.


Assuntos
Nanopartículas , Nanoestruturas , Estereoisomerismo , Dicroísmo Circular , Nanopartículas/química , Metais
7.
Angew Chem Int Ed Engl ; 61(32): e202207130, 2022 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-35672265

RESUMO

Covalent organic frameworks (COFs) are appealing photocatalysts for toxic chemical degradation. Great efforts have been devoted to regulate the photocatalytic performance of COFs by tuning their organic building blocks, but the relationship between COF linkage and photochemical properties has rarely been explored. Herein, we report the synthesis and characterisation of a novel aminal-linked porphyrinic COF, namely Por-Aminal-COF. Por-Aminal-COF (0.25 mol %) showed excellent photocatalytic activity toward the detoxification of the sulfur mustard simulant with a half-life (t1/2 ) of 5 min, which is far lower than that of traditional imine-linked Por-COF (t1/2 =16 min). Transient absorption spectroscopy indicated that the aminal linkages of Por-Aminal-COF facilitated the intersystem crossing process. Thus, Por-Aminal-COF showed higher triplet-state generation efficiency compared with Por-COF, consequently promoting the activation of oxygen molecular to singlet oxygen.

8.
Hum Mol Genet ; 27(4): 589-600, 2018 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-29267967

RESUMO

FRMPD4 (FERM and PDZ Domain Containing 4) is a neural scaffolding protein that interacts with PSD-95 to positively regulate dendritic spine morphogenesis, and with mGluR1/5 and Homer to regulate mGluR1/5 signaling. We report the genetic and functional characterization of 4 FRMPD4 deleterious mutations that cause a new X-linked intellectual disability (ID) syndrome. These mutations were found to be associated with ID in ten affected male patients from four unrelated families, following an apparent X-linked mode of inheritance. Mutations include deletion of an entire coding exon, a nonsense mutation, a frame-shift mutation resulting in premature termination of translation, and a missense mutation involving a highly conserved amino acid residue neighboring FRMPD4-FERM domain. Clinical features of these patients consisted of moderate to severe ID, language delay and seizures alongside with behavioral and/or psychiatric disturbances. In-depth functional studies showed that a frame-shift mutation, FRMPD4p.Cys618ValfsX8, results in a disruption of FRMPD4 binding with PSD-95 and HOMER1, and a failure to increase spine density in transfected hippocampal neurons. Behavioral studies of frmpd4-KO mice identified hippocampus-dependent spatial learning and memory deficits in Morris Water Maze test. These findings point to an important role of FRMPD4 in normal cognitive development and function in humans and mice, and support the hypothesis that FRMPD4 mutations cause ID by disrupting dendritic spine morphogenesis in glutamatergic neurons.


Assuntos
Espinhas Dendríticas/metabolismo , Deficiência Intelectual/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Adolescente , Adulto , Idoso , Éxons/genética , Feminino , Mutação da Fase de Leitura/genética , Humanos , Masculino , Pessoa de Meia-Idade , Morfogênese/genética , Morfogênese/fisiologia , Mutação/genética , Neurogênese/genética , Neurogênese/fisiologia , Linhagem , Adulto Jovem
9.
Mol Cell Neurosci ; 98: 121-130, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31212013

RESUMO

Kv4.2 voltage-gated K+ channel subunits, the primary source of the somatodendritic A-type K+ current in CA1 pyramidal neurons of the hippocampus, play important roles in regulating dendritic excitability and plasticity. To better study the trafficking and subcellular distribution of Kv4.2, we created and characterized a novel Kv4.2 construct encoding a bungarotoxin binding site in the extracellular S3-S4 linker region of the α-subunit. When expressed, this construct can be visualized in living cells after staining with rhodamine-conjugated bungarotoxin. We validated the utility of this construct by visualizing the spontaneous internalization and insertion of Kv4.2 in HEK 293T cells. We further report that Kv4.2 colocalized with several endosome markers in HEK 293T cells. In addition, Kv4.2 internalization is significantly impaired by mitogen-activated protein kinase (MAPK) inhibitors in transfected primary hippocampal neurons. Therefore, this newly developed BBS-Kv4.2 construct provides a novel and powerful tool for studying surface Kv4.2 channel localization and trafficking.


Assuntos
Bungarotoxinas/farmacologia , Canais de Potássio Shal/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Sítios de Ligação , Células Cultivadas , Dipeptidil Peptidases e Tripeptidil Peptidases/metabolismo , Células HEK293 , Hipocampo/citologia , Humanos , Proteínas Interatuantes com Canais de Kv/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Ligação Proteica , Inibidores de Proteínas Quinases/farmacologia , Transporte Proteico , Ratos , Canais de Potássio Shal/química , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores
10.
Int J Mol Sci ; 21(16)2020 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-32824677

RESUMO

The subthreshold, transient A-type K+ current is a vital regulator of the excitability of neurons throughout the brain. In mammalian hippocampal pyramidal neurons, this current is carried primarily by ion channels comprising Kv4.2 α-subunits. These channels occupy the somatodendritic domains of these principle excitatory neurons and thus regulate membrane voltage relevant to the input-output efficacy of these cells. Owing to their robust control of membrane excitability and ubiquitous expression in the hippocampus, their dysfunction can alter network stability in a manner that manifests in recurrent seizures. Indeed, growing evidence implicates these channels in intractable epilepsies of the temporal lobe, which underscores the importance of determining the molecular mechanisms underlying their regulation and contribution to pathologies. Here, we describe the role of p38 kinase phosphorylation of a C-terminal motif in Kv4.2 in modulating hippocampal neuronal excitability and behavioral seizure strength. Using a combination of biochemical, single-cell electrophysiology, and in vivo seizure techniques, we show that kainic acid-induced seizure induces p38-mediated phosphorylation of Thr607 in Kv4.2 in a time-dependent manner. The pharmacological and genetic disruption of this process reduces neuronal excitability and dampens seizure intensity, illuminating a cellular cascade that may be targeted for therapeutic intervention to mitigate seizure intensity and progression.


Assuntos
Convulsões/metabolismo , Canais de Potássio Shal/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Potenciais de Ação , Motivos de Aminoácidos , Animais , Ondas Encefálicas , Feminino , Células HEK293 , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/fisiopatologia , Humanos , Ácido Caínico/toxicidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , Neurônios/fisiologia , Fosforilação , Convulsões/etiologia , Convulsões/fisiopatologia , Canais de Potássio Shal/química
11.
J Pharmacol Exp Ther ; 361(1): 122-129, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28179473

RESUMO

In rat sympathetic neurons from the superior cervical ganglia (SCG) expressing metabotropic glutamate receptor mGluR1 or mGluR5, overexpression of scaffolding Homer proteins, which bind to a Homer ligand in their C termini, cause receptor clustering and uncoupling from ion channel modulation. In the absence of recombinant Homer protein overexpression, uncoupling of mGluRs from voltage-dependent channels can be induced by expression of Preso1, an adaptor of proline-directed kinases that phosphorylates the Homer ligand and recruits binding of endogenous Homer proteins. Here we show that in SCG neurons expressing mGluR1 and the tyrosine receptor kinase B, treatment with brain-derived neurotrophic factor (BDNF) produces a similar uncoupling of the receptors from calcium channels. We investigated the pathways that mediate this uncoupling and compared it with uncoupling observed with Preso1 expression. Both BDNF- and Preso1-induced uncoupling require residues T1151 and S1154 in the mGluR1 Homer ligand (TPPSPF). Uncoupling via Preso1 but not BDNF was prevented by expression of a dominant negative Cdk5, suggesting that endogenous Cdk5 mediates Preso1-dependent phosphorylation of mGluR1. Dominant negative Cdk5 did not block the BDNF effect but this was sensitive to inhibitors of the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase cascade. Interestingly, the BDNF pathway appeared to require native Preso1 binding to mGluR, because overexpression of the Preso1 FERM domain, which mediates the Preso1-mGluR interaction, prevented BDNF-induced uncoupling. These data suggest that the BDNF/tyrosine receptor kinase B and Cdk5 pathways converge at the level of mGluR to similarly induce Homer ligand phosphorylation, recruit Homer binding, and uncouple mGluRs from channel regulation.


Assuntos
Proteínas de Arcabouço Homer/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Proteínas do Tecido Nervoso/biossíntese , Receptores de Glutamato Metabotrópico/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/fisiologia , Ratos , Ratos Wistar
12.
Natl Sci Rev ; 11(7): nwae174, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38887544

RESUMO

Chemically modified superatoms have emerged as promising candidates in the new periodic table, in which Au13 and its doped M n Au13- n have been widely studied. However, their important counterpart, Ag13 artificial element, has not yet been synthesized. In this work, we report the synthesis of Ag13 nanoclusters using strong chelating ability and rigid ligands, that fills the gaps in the icosahedral superatomic metal clusters. After further doping Ag13 template with different degrees of Au atoms, we gained insight into the evolution of their optical properties. Theoretical calculations show that the kernel metal doping can modulate the transition of the excited-state electronic structure, and the electron transfer process changes from local excitation (LE) to charge transfer (CT) to LE. This study not only enriches the families of artificial superatoms, but also contributes to the understanding of the electronic states of superatomic clusters.

13.
Chem Commun (Camb) ; 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38922126

RESUMO

Detailed photophysical processes of two AuCu14 clusters with different substituents (-F or -C(CH3)3) of the thiol ligand were studied in this work. The electronic effect of the substituents led to structural shrinkage, thus enhancing the luminous intensity. The internal conversion (IC) and intersystem crossing (ISC) rates in the AuCu14-C(CH3)3 crystal were slower compared with the AuCu14-F crystal, which was caused by the steric effect.

14.
J Neurosci ; 32(13): 4651-9, 2012 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-22457511

RESUMO

The consolidation of conditioned fear involves upregulation of genes necessary for long-term memory formation. An important question remains as to whether this results in part from epigenetic regulation and chromatin modulation. We examined whether Homer1a, which is required for memory formation, is necessary for Pavlovian cued fear conditioning, whether it is downstream of BDNF-TrkB activation, and whether this pathway utilizes histone modifications for activity-dependent transcriptional regulation. We initially found that Homer1a knock-out mice exhibited deficits in cued fear conditioning (5 tone-shock presentations with 70 dB, 6 kHz tones and 0.5 s, 0.6 mA footshocks). We then demonstrated that: (1) Homer1a mRNA increases after fear conditioning in vivo within both amygdala and hippocampus of wild-type mice; (2) it increases after BDNF application to primary hippocampal and amygdala cultures in vitro; and (3) these increases are dependent on transcription and MAPK signaling. Furthermore, using chromatin immunoprecipitation we found that both in vitro and in vivo manipulations result in decreases in Homer1 promoter H3K9 methylation in amygdala cells but increases in Homer1 promoter H3 acetylation in hippocampal cells. However, no changes were observed in H4 acetylation or H3K27 dimethylation. Inhibition of histone deacetylation by sodium butyrate enhanced contextual but not cued fear conditioning and enhanced Homer1 H3 acetylation in the hippocampus. These data provide evidence for dynamic epigenetic regulation of Homer1a following BDNF-induced plasticity and during a BDNF-dependent learning process. Furthermore, upregulation of this gene may be regulated through distinct epigenetic modifications in the hippocampus and amygdala.


Assuntos
Tonsila do Cerebelo/metabolismo , Proteínas de Transporte/biossíntese , Condicionamento Clássico/fisiologia , Epigênese Genética/fisiologia , Medo/fisiologia , Regulação da Expressão Gênica/fisiologia , Hipocampo/metabolismo , Tonsila do Cerebelo/efeitos dos fármacos , Tonsila do Cerebelo/fisiologia , Animais , Fator Neurotrófico Derivado do Encéfalo/farmacologia , Proteínas de Transporte/genética , Condicionamento Clássico/efeitos dos fármacos , Medo/efeitos dos fármacos , Medo/psicologia , Regulação da Expressão Gênica/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Hipocampo/fisiologia , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/metabolismo , Proteínas de Arcabouço Homer , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Quinases Ativadas por Mitógeno/fisiologia , Cultura Primária de Células , Regiões Promotoras Genéticas/fisiologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Transcrição Gênica/fisiologia
15.
Nat Commun ; 14(1): 4121, 2023 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-37433775

RESUMO

Bright and efficient chiral coinage metal clusters show promise for use in emerging circularly polarized light-emitting materials and diodes. To date, highly efficient circularly polarized organic light-emitting diodes (CP-OLEDs) with enantiopure metal clusters have not been reported. Herein, through rational design of a multidentate chiral N-heterocyclic carbene (NHC) ligand and a modular building strategy, we synthesize a series of enantiopure Au(I)-Cu(I) clusters with exceptional stability. Modulation of the ligands stabilize the chiral excited states of clusters to allow thermally activated delayed fluorescence, resulting in the highest orange-red photoluminescence quantum yields over 93.0% in the solid state, which is accompanied by circularly polarized luminescence. Based on the solution process, a prototypical orange-red CP-OLED with a considerably high external quantum efficiency of 20.8% is prepared. These results demonstrate the extensive designability of chiral NHC ligands to stabilize polymetallic clusters for high performance in chiroptical applications.

16.
Alcohol Clin Exp Res ; 36(9): 1623-33, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22432643

RESUMO

BACKGROUND: Alcohol increases the expression of Group 1 metabotropic glutamate receptors (mGluRs) and their associated scaffolding protein Homer2 and stimulates phosphatidylinositol 3-kinase (PI3K) within the nucleus accumbens (NAC). Moreover, functional studies suggest that NAC Group 1 mGluR/Homer2/PI3K signaling may be a potential target for pharmacotherapeutic intervention in alcoholism. METHODS: Immunoblotting was conducted to examine the effects of alcohol consumption under drinking-in-the-dark (DID) procedures on Group 1 mGluR-associated proteins in C57BL/6J (B6) mice. Follow-up behavioral studies examined the importance of Group 1 mGluR/Homer2/PI3K signaling within the NAC shell for limited-access alcohol drinking. Finally, immunoblotting examined whether the NAC expression of Group 1 mGluR-associated proteins is a genetic correlate of high alcohol drinking using a selectively bred high DID (HDID-1) mouse line. RESULTS: Limited-access alcohol drinking under DID procedures up-regulated NAC shell Homer2 levels, concomitant with increases in mGluR5 and NR2B. Intra-NAC shell blockade of mGluR5, Homer2, or PI3K signaling, as well as transgenic disruption of the Homer binding site on mGluR5, decreased alcohol consumption in B6 mice. Moreover, transgenic disruption of the Homer binding site on mGluR5 and Homer2 deletion both prevented the attenuating effect of mGluR5 and PI3K blockade upon intake. Finally, the basal NAC shell protein expression of mGluR1 and Homer2 was increased in offspring of HDID-1 animals. CONCLUSIONS: Taken together, these data further implicate Group 1 mGluR signaling through Homer2 within the NAC in excessive alcohol consumption.


Assuntos
Alcoolismo/genética , Alcoolismo/fisiopatologia , Núcleo Accumbens/fisiologia , Receptores de Ácido Caínico/genética , Receptores de Ácido Caínico/fisiologia , Alcoolismo/psicologia , Animais , Western Blotting , Proteínas de Transporte/genética , Depressores do Sistema Nervoso Central/sangue , Etanol/sangue , Proteínas de Arcabouço Homer , Masculino , Camundongos , Camundongos Knockout , Fosfatidilinositol 3-Quinases/fisiologia , Receptores de N-Metil-D-Aspartato/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
17.
Front Cell Neurosci ; 16: 1070305, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36568885

RESUMO

Proteins usually form complexes to fulfill variable physiological functions. In neurons, communication relies on synapses where receptors, channels, and anchoring proteins form complexes to precisely control signal transduction, synaptic integration, and action potential firing. Although there are many published protocols to isolate protein complexes in cell lines, isolation in neurons has not been well established. Here we introduce a method that combines lentiviral protein expression with tandem affinity purification followed by mass-spectrometry (TAP-MS) to identify protein complexes in neurons. This protocol can also be used to identify post-translational modifications (PTMs) of synaptic proteins. We used the A-type voltage-gated K+ channel subunit Kv4.2 as the target protein. Kv4.2 is highly expressed in the hippocampus where it contributes to learning and memory through its regulation of neuronal excitability and synaptic plasticity. We tagged Kv4.2 with the calmodulin-binding-peptide (CBP) and streptavidin-binding-peptide (SBP) at its C-terminus and expressed it in neurons via lentivirus. Kv4.2 was purified by two-step TAP and samples were analyzed by MS. MS identified two prominently known Kv4.2 interacting proteins [dipeptidyl peptidase like (DPPs) and Kv channel-interacting proteins (KChIPs)] in addition to novel synaptic proteins including glutamate receptors, a calcium channel, and anchoring proteins. Co-immunoprecipitation and colocalization experiments validated the association of Kv4.2 with glutamate receptors. In addition to protein complex identification, we used TAP-MS to identify Kv4.2 phosphorylation sites. Several known and unknown phosphorylation sites were identified. These findings provide a novel path to identify protein-protein interactions and PTMs in neurons and shed light on mechanisms of neuronal signaling potentially involved in the pathology of neurological diseases.

18.
Adv Sci (Weinh) ; 9(2): e2103721, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34761563

RESUMO

Superbugs are bacteria that have grown resistant to most antibiotics, seriously threating the health of people. Silver (Ag) nanoparticles are known to exert a wide-spectrum antimicrobial property, yet remains challenging against superbugs. Here, Ag clusters are assembled using porphyrin-based linkers and a novel framework structure (Ag9 -AgTPyP) is produced, in which nine-nuclearity Ag9 clusters are uniformly separated by Ag-centered porphyrin units (AgTPyP) in two dimensions, demonstrating open permeant porosity. Ag9 -AgTPyP eliminates over 99.99999% and 99.999% methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (P. aeruginosa) within 2 h upon visible-light irradiation, which are superior to a majority of bacteria inactivation photocatalysts. The novel-established long-term charge-transfer states from AgTPyP to adjacent Ag9 cluster that has preferential affinity to O2 greatly promote reactive oxygen species (ROS) production efficiency; and its unique framework accelerates the ROS transportation. Personal protective equipment (masks and protective suits) incorporating Ag9 -AgTPyP film also shows excellent performances against superbugs. This superbugs-killing efficiency is unprecedented among silver complexes and porphyrin derivatives. Utilizing efficient photogenerated electrons and holes between metal cluster and linkers can open up new interests of research in photocatalytic areas.


Assuntos
Antibacterianos/química , Antibacterianos/uso terapêutico , Nanopartículas Metálicas/química , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Porfirinas/química , Pseudomonas aeruginosa/efeitos dos fármacos , Prata/química
19.
J Neurosci ; 29(27): 8655-68, 2009 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-19587272

RESUMO

The glutamate receptor-associated protein Homer2 regulates alcohol-induced neuroplasticity within the nucleus accumbens (NAC), but the precise intracellular signaling cascades involved are not known. This study examined the role for NAC metabotropic glutamate receptor (mGluR)-Homer2-phosphatidylinositol 3-kinase (PI3K) signaling in regulating excessive alcohol consumption within the context of the scheduled high alcohol consumption (SHAC) model of binge alcohol drinking. Repeated bouts of binge drinking ( approximately 1.5 g/kg per 30 min) elevated NAC Homer2a/b expression and increased PI3K activity in this region. Virus-mediated knockdown of NAC Homer2b expression attenuated alcohol intake, as did an intra-NAC infusion of the mGluR5 antagonist MPEP [2-methyl-6-(phenylethynyl)pyridine hydrochloride] (0.1-1 microg/side) and the PI3K antagonist wortmannin (50 ng/side), supporting necessary roles for mGluR5/Homer2/PI3K in binge alcohol drinking. Moreover, when compared with wild-type littermates, transgenic mice with an F1128R point mutation in mGluR5 that markedly reduces Homer binding exhibited a 50% reduction in binge alcohol drinking, which was related to reduced NAC basal PI3K activity. Consistent with the hypothesis that mGluR5-Homer-PI3K signaling may be a mechanism governing excessive alcohol intake, the "anti-binge" effects of MPEP and wortmannin were not additive, nor were they observed in the mGluR5(F1128R) transgenic mice. Finally, mice genetically selected for a high versus low SHAC phenotype differed in NAC mGluR, Homer2, and PI3K activity, consistent with the hypothesis that augmented NAC mGluR5-Homer2-PI3K signaling predisposes a high binge alcohol-drinking phenotype. Together, these data point to an important role for NAC mGluR5-Homer2-PI3K signaling in regulating binge-like alcohol consumption that has relevance for our understanding of the neurobiology of alcoholism and its pharmacotherapy.


Assuntos
Alcoolismo/metabolismo , Proteínas de Transporte/fisiologia , Etanol/toxicidade , Núcleo Accumbens/metabolismo , Fosfatidilinositol 3-Quinases/fisiologia , Receptores de Glutamato Metabotrópico/fisiologia , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima/fisiologia , Alcoolismo/enzimologia , Alcoolismo/genética , Animais , Proteínas de Transporte/biossíntese , Proteínas de Transporte/genética , Proteínas de Arcabouço Homer , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/enzimologia , Fenótipo , Fosfatidilinositol 3-Quinases/biossíntese , Fosfatidilinositol 3-Quinases/genética , Receptor de Glutamato Metabotrópico 5 , Receptores de Glutamato Metabotrópico/biossíntese , Receptores de Glutamato Metabotrópico/genética , Transdução de Sinais/fisiologia , Regulação para Cima/efeitos dos fármacos
20.
Nat Commun ; 11(1): 1567, 2020 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-32218435

RESUMO

Voltage-gated K+ channels function in macromolecular complexes with accessory subunits to regulate brain function. Here, we describe a peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1)-dependent mechanism that regulates the association of the A-type K+ channel subunit Kv4.2 with its auxiliary subunit dipeptidyl peptidase 6 (DPP6), and thereby modulates neuronal excitability and cognitive flexibility. We show that activity-induced Kv4.2 phosphorylation triggers Pin1 binding to, and isomerization of, Kv4.2 at the pThr607-Pro motif, leading to the dissociation of the Kv4.2-DPP6 complex. We generated a novel mouse line harboring a knock-in Thr607 to Ala (Kv4.2TA) mutation that abolished dynamic Pin1 binding to Kv4.2. CA1 pyramidal neurons of the hippocampus from these mice exhibited altered Kv4.2-DPP6 interaction, increased A-type K+ current, and reduced neuronal excitability. Behaviorally, Kv4.2TA mice displayed normal initial learning but improved reversal learning in both Morris water maze and lever press paradigms. These findings reveal a Pin1-mediated mechanism regulating reversal learning and provide potential targets for the treatment of neuropsychiatric disorders characterized by cognitive inflexibility.


Assuntos
Cognição , Peptidilprolil Isomerase de Interação com NIMA/metabolismo , Canais de Potássio Shal/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Dipeptidil Peptidases e Tripeptidil Peptidases/metabolismo , Células HEK293 , Humanos , Imidazóis/farmacologia , Ativação do Canal Iônico/efeitos dos fármacos , Isomerismo , Aprendizagem , Camundongos , Modelos Biológicos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Fosforilação/efeitos dos fármacos , Fosfotreonina/metabolismo , Ligação Proteica , Células Piramidais/efeitos dos fármacos , Células Piramidais/metabolismo , Piridinas/farmacologia , Convulsões/metabolismo , Convulsões/patologia , Canais de Potássio Shal/química , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA