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1.
J Neuropathol Exp Neurol ; 79(2): 123-143, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31913484

RESUMO

The proposed molecular mechanisms underlying neurodegenerative pathogenesis are varied, precluding the development of effective therapies for these increasingly prevalent disorders. One of the most consistent observations across neurodegenerative diseases is the phosphorylation of eukaryotic initiation factor 2α (eIF2α). eIF2α is a translation initiation factor, involved in cap-dependent protein translation, which when phosphorylated causes global translation attenuation. eIF2α phosphorylation is mediated by 4 kinases, which, together with their downstream signaling cascades, constitute the integrated stress response (ISR). While the ISR is activated by stresses commonly observed in neurodegeneration, such as oxidative stress, endoplasmic reticulum stress, and inflammation, it is a canonically adaptive signaling cascade. However, chronic activation of the ISR can contribute to neurodegenerative phenotypes such as neuronal death, memory impairments, and protein aggregation via apoptotic induction and other maladaptive outcomes downstream of phospho-eIF2α-mediated translation inhibition, including neuroinflammation and altered amyloidogenic processing, plausibly in a feed-forward manner. This review examines evidence that dysregulated eIF2a phosphorylation acts as a driver of neurodegeneration, including a survey of observations of ISR signaling in human disease, inspection of the overlap between ISR signaling and neurodegenerative phenomenon, and assessment of recent encouraging findings ameliorating neurodegeneration using developing pharmacological agents which target the ISR. In doing so, gaps in the field, including crosstalk of the ISR kinases and consideration of ISR signaling in nonneuronal central nervous system cell types, are highlighted.


Assuntos
Fator de Iniciação 2 em Eucariotos/metabolismo , Doenças Neurodegenerativas/metabolismo , Estresse Fisiológico , Animais , Regulação da Expressão Gênica , Humanos , Fosforilação , Transdução de Sinais
2.
Med Probl Perform Art ; 34(2): 118-119, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31152656

RESUMO

Is it anxiety or arousal that can facilitate musical performance? This is a complicated question that begs for clarification. This letter is an attempt to dig into the issue by framing some of the core questions that will hopefully lead to a greater understanding.


Assuntos
Ansiedade , Nível de Alerta , Música , Drama , Humanos
3.
J Neurosci ; 38(18): 4288-4300, 2018 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-29632166

RESUMO

HIV-associated neurocognitive disorders (HANDs) share common symptoms with Alzheimer's disease (AD), which is characterized by amyloid-ß (Aß) plaques. Plaques are formed by aggregation of Aß oligomers, which may be the toxic species in AD pathogenesis, and oligomers are generated by cleavage of amyloid precursor protein (APP) by ß-site amyloid precursor protein cleaving enzyme 1 (BACE1). BACE1 inhibitors reverse neuronal loss and cognitive decline in animal models of AD. Although studies have also found evidence of altered APP processing in HIV+ patients, it is unknown whether increased BACE1 expression or Aß oligomer production is a common neuropathological feature of HAND. Moreover, it is unknown whether BACE1 or APP is involved in the excitotoxic, NMDAR-dependent component of HIV-associated neurotoxicity in vitro Herein, we hypothesize that HIV-associated neurotoxicity is mediated by NMDAR-dependent elevation of BACE1 and subsequent altered processing of APP. Supporting this, we observed elevated levels of BACE1 and Aß oligomers in CNS of male and female HIV+ patients. In a model of HIV-associated neurotoxicity in which rat neurons are treated with supernatants from HIV-infected human monocyte-derived macrophages, we observed NMDAR-dependent elevation of BACE1 protein. NMDA treatment also increased BACE1 and both pharmacological BACE1 inhibition and genetic loss of APP were partially neuroprotective. Moreover, in APP knock-out (APP-/-) mouse neurons, NMDA-induced toxicity was BACE1 independent, indicating that cytotoxicity of BACE1 is dependent upon APP cleavage. Our findings suggest that increased BACE1 and the resultant Aß oligomer production may contribute to HIV-associated neuropathogenesis and inhibition of BACE1 could have therapeutic potential in HANDs.SIGNIFICANCE STATEMENT HIV-associated neurocognitive disorders (HANDs) represent a range of cognitive impairments affecting ∼50% of HIV+ individuals. The specific causes of HAND are unknown, but evidence suggests that HIV-infected macrophage infiltration into the brain may cause neuronal damage. Herein, we show that neurons treated with conditioned media from HIV-infected macrophages have increased expression of ß-site amyloid precursor protein cleaving enzyme 1 (BACE1), a protein implicated in Alzheimer's disease pathogenesis. Moreover, inhibition of BACE1 prevented neuronal loss after conditioned media exposure, but had no effect on HIV-associated neurotoxicity in neurons lacking its cleavage target amyloid precursor protein. We also observed increased BACE1 expression in HIV+ patient brain tissue, confirming the potential relevance of BACE1 as a therapeutic target in HANDs.


Assuntos
Complexo AIDS Demência/genética , Complexo AIDS Demência/patologia , Secretases da Proteína Precursora do Amiloide/genética , Precursor de Proteína beta-Amiloide/genética , Ácido Aspártico Endopeptidases/genética , Infecções por HIV/patologia , Neurônios/patologia , Adulto , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Animais , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Agonistas de Aminoácidos Excitatórios/toxicidade , Feminino , Hipocampo/metabolismo , Humanos , Macrófagos/química , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , N-Metilaspartato/toxicidade , Ratos , Ratos Sprague-Dawley , Receptores de N-Metil-D-Aspartato/genética
4.
Am J Pathol ; 187(1): 91-109, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27993242

RESUMO

Mounting evidence implicates antiretroviral (ARV) drugs as potential contributors to the persistence and evolution of clinical and pathological presentation of HIV-associated neurocognitive disorders in the post-ARV era. Based on their ability to induce endoplasmic reticulum (ER) stress in various cell types, we hypothesized that ARV-mediated ER stress in the central nervous system resulted in chronic dysregulation of the unfolded protein response and altered amyloid precursor protein (APP) processing. We used in vitro and in vivo models to show that HIV protease inhibitor (PI) class ARVs induced neuronal damage and ER stress, leading to PKR-like ER kinase-dependent phosphorylation of the eukaryotic translation initiation factor 2α and enhanced translation of ß-site APP cleaving enzyme-1 (BACE1). In addition, PIs induced ß-amyloid production, indicative of increased BACE1-mediated APP processing, in rodent neuroglial cultures and human APP-expressing Chinese hamster ovary cells. Inhibition of BACE1 activity protected against neuronal damage. Finally, ARVs administered to mice and SIV-infected macaques resulted in neuronal damage and BACE1 up-regulation in the central nervous system. These findings implicate a subset of PIs as potential mediators of neurodegeneration in HIV-associated neurocognitive disorders.


Assuntos
Secretases da Proteína Precursora do Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Inibidores da Protease de HIV/farmacologia , Biossíntese de Proteínas/efeitos dos fármacos , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Animais , Axônios/efeitos dos fármacos , Axônios/metabolismo , Axônios/patologia , Células Cultivadas , Macaca , Masculino , Camundongos Endogâmicos C57BL , Proteínas Associadas aos Microtúbulos/metabolismo , Neuroglia/efeitos dos fármacos , Neuroglia/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Estabilidade Proteica/efeitos dos fármacos , Ratos , Ritonavir/farmacologia , Resposta a Proteínas não Dobradas/efeitos dos fármacos , eIF-2 Quinase/metabolismo
5.
J Neuropathol Exp Neurol ; 74(11): 1093-118, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26469251

RESUMO

Despite effective viral suppression through combined antiretroviral therapy (cART), approximately half of HIV-positive individuals have HIV-associated neurocognitive disorders (HAND). Studies of antiretroviral-treated patients have revealed persistent white matter abnormalities including diffuse myelin pallor, diminished white matter tracts, and decreased myelin protein mRNAs. Loss of myelin can contribute to neurocognitive dysfunction because the myelin membrane generated by oligodendrocytes is essential for rapid signal transduction and axonal maintenance. We hypothesized that myelin changes in HAND are partly due to effects of antiretroviral drugs on oligodendrocyte survival and/or maturation. We showed that primary mouse oligodendrocyte precursor cell cultures treated with therapeutic concentrations of HIV protease inhibitors ritonavir or lopinavir displayed dose-dependent decreases in oligodendrocyte maturation; however, this effect was rapidly reversed after drug removal. Conversely, nucleoside reverse transcriptase inhibitor zidovudine had no effect. Furthermore, in vivo ritonavir administration to adult mice reduced frontal cortex myelin protein levels. Finally, prefrontal cortex tissue from HIV-positive individuals with HAND on cART showed a significant decrease in myelin basic protein compared with untreated HIV-positive individuals with HAND or HIV-negative controls. These findings demonstrate that antiretrovirals can impact myelin integrity and have implications for myelination in juvenile HIV patients and myelin maintenance in adults on lifelong therapy.


Assuntos
Antirreumáticos/uso terapêutico , Regulação Viral da Expressão Gênica/efeitos dos fármacos , Infecções por HIV , Bainha de Mielina/efeitos dos fármacos , Oligodendroglia/efeitos dos fármacos , Adulto , Animais , Animais Recém-Nascidos , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Transtornos Cognitivos/etiologia , Estudos de Coortes , Modelos Animais de Doenças , Gangliosídeos/metabolismo , Regulação Viral da Expressão Gênica/fisiologia , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Infecções por HIV/patologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Proteína Básica da Mielina/metabolismo , Proteína Proteolipídica de Mielina/metabolismo , Bainha de Mielina/virologia , Oligodendroglia/virologia , Espécies Reativas de Oxigênio/metabolismo
6.
Plant Cell ; 27(5): 1547-62, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25966763

RESUMO

Nod-like receptors (NLRs) serve as immune receptors in plants and animals. The stability of NLRs is tightly regulated, though its mechanism is not well understood. Here, we show the crucial impact of N-terminal acetylation on the turnover of one plant NLR, Suppressor of NPR1, Constitutive 1 (SNC1), in Arabidopsis thaliana. Genetic and biochemical analyses of SNC1 uncovered its multilayered regulation by different N-terminal acetyltransferase (Nat) complexes. SNC1 exhibits a few distinct N-terminal isoforms generated through alternative initiation and N-terminal acetylation. Its first Met is acetylated by N-terminal acetyltransferase complex A (NatA), while the second Met is acetylated by N-terminal acetyltransferase complex B (NatB). Unexpectedly, the NatA-mediated acetylation serves as a degradation signal, while NatB-mediated acetylation stabilizes the NLR protein, thus revealing antagonistic N-terminal acetylation of a single protein substrate. Moreover, NatA also contributes to the turnover of another NLR, RESISTANCE TO P. syringae pv maculicola 1. The intricate regulation of protein stability by Nats is speculated to provide flexibility for the target protein in maintaining its homeostasis.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Acetiltransferases N-Terminal/metabolismo , Acetilação , Sequência de Aminoácidos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Mapeamento Cromossômico , Clonagem Molecular , Modelos Biológicos , Dados de Sequência Molecular , Mutação , Acetiltransferases N-Terminal/genética , Estabilidade Proteica , Plântula/enzimologia , Plântula/genética , Alinhamento de Sequência , Nicotiana/enzimologia , Nicotiana/genética
7.
Vis Neurosci ; 31(1): 1-10, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24801619

RESUMO

Retinal pigment epithelial cells of teleosts contain numerous melanosomes (pigment granules) that exhibit light-dependent motility. In light, melanosomes disperse out of the retinal pigment epithelium (RPE) cell body (CB) into long apical projections that interdigitate with rod photoreceptors, thus shielding the photoreceptors from bleaching. In darkness, melanosomes aggregate through the apical projections back into the CB. Previous research has demonstrated that melanosome motility in the RPE CB requires microtubules, but in the RPE apical projections, actin filaments are necessary and sufficient for motility. We used myosin S1 labeling and platinum replica shadowing of dissociated RPE cells to determine actin filament polarity in apical projections. Actin filament bundles within RPE apical projections are uniformly oriented with barbed ends toward the distal tips. Treatment of RPE cells with the tetravalent lectin, Concanavalin A, which has been shown to suppress cortical actin flow by crosslinking of cell-surface proteins, inhibited melanosome aggregation and stimulated ectopic filopodia formation but did not block melanosome dispersion. The polarity orientation of F-actin in apical projections suggests that a barbed-end directed myosin motor could effect dispersion of melanosomes from the CB into apical projections. Inhibition of aggregation, but not dispersion, by ConA confirms that different actin-dependent mechanisms control these two processes and suggests that melanosome aggregation is sensitive to treatments previously shown to disrupt actin cortical flow.


Assuntos
Citoesqueleto de Actina/ultraestrutura , Concanavalina A/metabolismo , Melanossomas/fisiologia , Epitélio Pigmentado Ocular/citologia , Epitélio Pigmentado Ocular/metabolismo , Animais , Agregação Celular/fisiologia , Corrente Citoplasmática/fisiologia , Perciformes
8.
J Neurovirol ; 20(1): 39-53, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24420448

RESUMO

HIV-associated neurocognitive disorder (HAND), characterized by a wide spectrum of behavioral, cognitive, and motor dysfunctions, continues to affect approximately 50 % of HIV(+) patients despite the success of combination antiretroviral drug therapy (cART) in the periphery. Of note, potential toxicity of antiretroviral drugs in the central nervous system (CNS) remains remarkably underexplored and may contribute to the persistence of HAND in the cART era. Previous studies have shown antiretrovirals (ARVs) to be neurotoxic in the peripheral nervous system in vivo and in peripheral neurons in vitro. Alterations in lipid and protein metabolism, mitochondrial damage, and oxidative stress all play a role in peripheral ARV neurotoxicity. We hypothesized that ARVs also induce cellular stresses in the CNS, ultimately leading to neuronal damage and contributing to the changing clinical and pathological picture seen in HIV-positive patients in the cART era. In this report, we show that ARVs are neurotoxic in the CNS in both pigtail macaques and rats in vivo. Furthermore, in vitro, ARVs lead to accumulation of reactive oxygen species (ROS), and ultimately induction of neuronal damage and death. Whereas ARVs alone caused some activation of the endogenous antioxidant response in vitro, augmentation of this response by a fumaric acid ester, monomethyl fumarate (MMF), blocked ARV-induced ROS generation, and neuronal damage/death. These findings implicate oxidative stress as a contributor to the underlying mechanisms of ARV-induced neurotoxicity and will provide an access point for adjunctive therapies to complement ARV therapy and reduce neurotoxicity in this patient population.


Assuntos
Complexo AIDS Demência/patologia , Antirretrovirais/toxicidade , Encéfalo/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Animais , Western Blotting , Encéfalo/patologia , Encéfalo/virologia , Morte Celular/efeitos dos fármacos , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Feminino , Imunofluorescência , Macaca , Masculino , Neurônios/patologia , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
9.
PLoS Genet ; 7(6): e1002159, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21738492

RESUMO

Transportin-SR (TRN-SR) is a member of the importin-ß super-family that functions as the nuclear import receptor for serine-arginine rich (SR) proteins, which play diverse roles in RNA metabolism. Here we report the identification and cloning of mos14 (modifier of snc1-1, 14), a mutation that suppresses the immune responses conditioned by the auto-activated Resistance (R) protein snc1 (suppressor of npr1-1, constitutive 1). MOS14 encodes a nuclear protein with high similarity to previously characterized TRN-SR proteins in animals. Yeast two-hybrid assays showed that MOS14 interacts with AtRAN1 via its N-terminus and SR proteins via its C-terminus. In mos14-1, localization of several SR proteins to the nucleus was impaired, confirming that MOS14 functions as a TRN-SR. The mos14-1 mutation results in altered splicing patterns of SNC1 and another R gene RPS4 and compromised resistance mediated by snc1 and RPS4, suggesting that nuclear import of SR proteins by MOS14 is required for proper splicing of these two R genes and is important for their functions in plant immunity.


Assuntos
Arabidopsis/genética , Arabidopsis/imunologia , Genes de Plantas/genética , Imunidade Vegetal/genética , Splicing de RNA/genética , beta Carioferinas/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/imunologia , Proteínas de Arabidopsis/metabolismo , Núcleo Celular/metabolismo , Regulação da Expressão Gênica de Plantas , Ordem dos Genes , Mutação/genética , Ligação Proteica/fisiologia , Transporte Proteico/genética , beta Carioferinas/genética , beta Carioferinas/imunologia
10.
Curr Opin Neurol ; 24(3): 275-83, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21467932

RESUMO

PURPOSE OF REVIEW: The present review discusses current concepts of HIV-associated neurocognitive disorders (HAND) in the era of antiretroviral therapy (ART). As the HIV epidemic enters its fourth decade (the second decade of ART), research must address evolving factors in HAND pathogenesis. These include persistent systemic and central nervous system (CNS) inflammation, aging in the HIV-infected brain, HIV subtype (clade) distribution, concomitant use of drugs of abuse, and potential neurotoxicity of ART drugs. RECENT FINDINGS: Although the severest form of HAND, HIV-associated dementia (HAD), is now rare due to ART, the persistence of milder, functionally important HAND forms persist in up to half of HIV-infected individuals. HAND prevalence may be higher in areas of Africa where different HIV subtypes predominate, and ART regimens that are more effective in suppressing CNS HIV replication can improve neurological outcomes. HAND are correlated with persistent systemic and CNS inflammation, and enhanced neuronal injury due to stimulant abuse (cocaine and methamphetamine), aging, and possibly ART drugs themselves. SUMMARY: Prevention and treatment of HAND requires strategies aimed at suppressing CNS HIV replication and effects of systemic and CNS inflammation in aging and substance-abusing HIV populations. Use of improved CNS-penetrating ART must be accompanied by evaluation of potential ART neurotoxicity.


Assuntos
Complexo AIDS Demência/fisiopatologia , Infecções por HIV/fisiopatologia , Complexo AIDS Demência/tratamento farmacológico , Complexo AIDS Demência/etiologia , Complexo AIDS Demência/patologia , Fármacos Anti-HIV/efeitos adversos , Fármacos Anti-HIV/uso terapêutico , Sistema Nervoso Central/patologia , Sistema Nervoso Central/virologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/patologia , HIV-1/imunologia , HIV-1/fisiologia , Humanos , Inflamação/complicações , Transtornos Relacionados ao Uso de Substâncias/complicações , Replicação Viral
11.
Int Arch Occup Environ Health ; 84(2): 131-7, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20589388

RESUMO

UNLABELLED: Following the World Trade Center (WTC) collapse on September 11, 2001, more than 40,000 people were exposed to a complex mixture of inhalable nanoparticles and toxic chemicals. While many developed chronic respiratory symptoms, to what degree olfaction was compromised is unclear. A previous WTC Medical Monitoring and Treatment Program study found that olfactory and nasal trigeminal thresholds were altered by the toxic exposure, but not scores on a 20-odor smell identification test. OBJECTIVES: To employ a well-validated 40-item smell identification test to definitively establish whether the ability to identify odors is compromised in a cohort of WTC-exposed individuals and, if so, whether the degree of compromise is associated with self-reported severity of rhinitic symptoms. METHODS: The University of Pennsylvania Smell Identification Test (UPSIT) was administered to 99 WTC-exposed persons and 99 matched normal controls. The Sino-Nasal Outcomes Test (SNOT-20) was administered to the 99 WTC-exposed persons and compared to the UPSIT scores. RESULTS: The mean (SD) UPSIT scores were lower in the WTC-exposed group than in age-, sex-, and smoking history-matched controls [respective scores: 30.05 (5.08) vs 35.94 (3.76); p = 0.003], an effect present in a subgroup of 19 subjects additionally matched on occupation (p < 0.001). Fifteen percent of the exposed subjects had severe microsmia, but only 3% anosmia. SNOT-20 scores were unrelated to UPSIT scores (r = 0.20; p = 0.11). CONCLUSION: Exposure to WTC air pollution was associated with a decrement in the ability to identify odors, implying that such exposure had a greater influence on smell function than previously realized.


Assuntos
Poluentes Atmosféricos/toxicidade , Exposição por Inalação , Exposição Ocupacional , Transtornos do Olfato/induzido quimicamente , Doenças Respiratórias/induzido quimicamente , Ataques Terroristas de 11 de Setembro , Adulto , Fatores Etários , Análise de Variância , Estudos de Casos e Controles , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Cidade de Nova Iorque/epidemiologia , Odorantes , Doenças Respiratórias/epidemiologia , Estudos Retrospectivos , Olfato
12.
Plant Cell ; 22(9): 3153-63, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20841424

RESUMO

Plant immune receptors belonging to the receptor-like protein (RLP) family contain extracellular leucine-rich repeats (LRRs) and a short cytoplasmic tail linked by a single transmembrane motif. Here, we report the identification of snc2-1D (for suppressor of npr1-1, constitutive 2), a semidominant Arabidopsis thaliana mutant with constitutively activated defense responses. Map-based cloning of snc2-1D showed that it encodes an RLP. The point mutation in snc2-1D leads to substitution of the second Gly for Arg in the conserved GXXXG motif of the transmembrane helix, suggesting that this residue is important for negative regulation of the protein. Epistasis analysis revealed that the snc2-1D mutant phenotype is not affected by mutations in genes known to be required for the nucleotide binding (NB)-LRR Resistance (R) protein signaling. A suppressor screen of snc2-1D was performed, and map-based cloning of one suppressor revealed that mutations in WRKY70 suppress the constitutive defense responses in snc2-1D, suggesting that WRKY70 functions downstream of snc2-1D. The identification of snc2-1D provides us with a unique system for genetic analysis of resistance pathways downstream of RLPs, which may be distinct from those downstream of NB-LRR type R proteins.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Fatores de Transcrição/metabolismo , Arabidopsis/imunologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Clonagem Molecular , Análise Mutacional de DNA , Epistasia Genética , Regulação da Expressão Gênica de Plantas , Imunidade Inata , Mutação Puntual , Fatores de Transcrição/genética
13.
J Neurosci ; 30(9): 3409-18, 2010 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-20203200

RESUMO

Aggregation of alpha-synuclein (alpha-syn), a process that generates oligomeric intermediates, is a common pathological feature of several neurodegenerative disorders. Despite the potential importance of the oligomeric alpha-syn intermediates in neuron function, their biochemical properties and pathobiological functions in vivo remain vastly unknown. Here we used two-dimensional analytical separation and an array of biochemical and cell-based assays to characterize alpha-syn oligomers that are present in the nervous system of A53T alpha-syn transgenic mice. The most prominent species identified were 53 A detergent-soluble oligomers, which preceded neurological symptom onset, and were found at equivalent amounts in regions containing alpha-syn inclusions as well as histologically unaffected regions. These oligomers were resistant to SDS, heat, and urea but were sensitive to proteinase-K digestion. Although the oligomers shared similar basic biochemical properties, those obtained from inclusion-bearing regions were prominently reactive to antibodies that recognize oxidized alpha-syn oligomers, significantly accelerated aggregation of alpha-syn in vitro, and caused primary cortical neuron degeneration. In contrast, oligomers obtained from non-inclusion-bearing regions were not toxic and delayed the in vitro formation of alpha-syn fibrils. These data indicate that specific conformations of alpha-syn oligomers are present in distinct brain regions of A53T alpha-syn transgenic mice. The contribution of these oligomers to the development of neuron dysfunction appears to be independent of their absolute quantities and basic biochemical properties but is dictated by the composition and conformation of the intermediates as well as unrecognized brain-region-specific intrinsic factors.


Assuntos
Encéfalo/metabolismo , Corpos de Lewy/metabolismo , Doenças Neurodegenerativas/metabolismo , Fragmentos de Peptídeos/metabolismo , alfa-Sinucleína/metabolismo , Amiloide/genética , Amiloide/metabolismo , Animais , Anticorpos/farmacologia , Especificidade de Anticorpos/fisiologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Células Cultivadas , Feminino , Humanos , Corpos de Lewy/patologia , Doença por Corpos de Lewy/genética , Doença por Corpos de Lewy/metabolismo , Doença por Corpos de Lewy/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Peso Molecular , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/fisiopatologia , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Doença de Parkinson/fisiopatologia , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/toxicidade , Polímeros/metabolismo , Proteínas PrPC/genética , Regiões Promotoras Genéticas/genética , Conformação Proteica , Solubilidade , alfa-Sinucleína/genética , alfa-Sinucleína/toxicidade
15.
Neuroimage ; 49(1): 994-1005, 2010 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-19679192

RESUMO

Deaf signers have extensive experience using their hands to communicate. Using fMRI, we examined the neural systems engaged during the perception of manual communication in 14 deaf signers and 14 hearing non-signers. Participants passively viewed blocked video clips of pantomimes (e.g., peeling an imaginary banana) and action verbs in American Sign Language (ASL) that were rated as meaningless by non-signers (e.g., TO-DANCE). In contrast to visual fixation, pantomimes strongly activated fronto-parietal regions (the mirror neuron system, MNS) in hearing non-signers, but only bilateral middle temporal regions in deaf signers. When contrasted with ASL verbs, pantomimes selectively engaged inferior and superior parietal regions in hearing non-signers, but right superior temporal cortex in deaf signers. The perception of ASL verbs recruited similar regions as pantomimes for deaf signers, with some evidence of greater involvement of left inferior frontal gyrus for ASL verbs. Functional connectivity analyses with left hemisphere seed voxels (ventral premotor, inferior parietal lobule, fusiform gyrus) revealed robust connectivity with the MNS for the hearing non-signers. Deaf signers exhibited functional connectivity with the right hemisphere that was not observed for the hearing group for the fusiform gyrus seed voxel. We suggest that life-long experience with manual communication, and/or auditory deprivation, may alter regional connectivity and brain activation when viewing pantomimes. We conclude that the lack of activation within the MNS for deaf signers does not support an account of human communication that depends upon automatic sensorimotor resonance between perception and action.


Assuntos
Sistema Nervoso Central/fisiologia , Surdez/fisiopatologia , Vias Neurais/fisiologia , Neurônios/fisiologia , Língua de Sinais , Percepção Visual/fisiologia , Adulto , Feminino , Fixação Ocular/fisiologia , Lateralidade Funcional/fisiologia , Gestos , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Córtex Motor/fisiologia , Lobo Parietal/fisiologia , Adulto Jovem
16.
PLoS Genet ; 6(12): e1001250, 2010 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-21203492

RESUMO

Nucleocytoplasmic trafficking is emerging as an important aspect of plant immunity. The three related pathways affecting plant immunity include Nuclear Localization Signal (NLS)-mediated nuclear protein import, Nuclear Export Signal (NES)-dependent nuclear protein export, and mRNA export relying on MOS3, a nucleoporin belonging to the Nup107-160 complex. Here we report the characterization, identification, and detailed analysis of Arabidopsis modifier of snc1, 11 (mos11). Mutations in MOS11 can partially suppress the dwarfism and enhanced disease resistance phenotypes of snc1, which carries a gain-of-function mutation in a TIR-NB-LRR type Resistance gene. MOS11 encodes a conserved eukaryotic protein with homology to the human RNA binding protein CIP29. Further functional analysis shows that MOS11 localizes to the nucleus and that the mos11 mutants accumulate more poly(A) mRNAs in the nucleus, likely resulting from reduced mRNA export activity. Epistasis analysis between mos3-1 and mos11-1 revealed that MOS11 probably functions in the same mRNA export pathway as MOS3, in a partially overlapping fashion, before the mRNA molecules pass through the nuclear pores. Taken together, MOS11 is identified as a new protein contributing to the transfer of mature mRNA from the nucleus to the cytosol.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Núcleo Celular/metabolismo , RNA Mensageiro/metabolismo , RNA de Plantas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Transporte Ativo do Núcleo Celular , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Transporte Biológico , Núcleo Celular/genética , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , RNA Mensageiro/genética , RNA de Plantas/genética , Proteínas de Ligação a RNA/genética
17.
Proc Natl Acad Sci U S A ; 106(49): 20664-9, 2009 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-19923436

RESUMO

Symbolic gestures, such as pantomimes that signify actions (e.g., threading a needle) or emblems that facilitate social transactions (e.g., finger to lips indicating "be quiet"), play an important role in human communication. They are autonomous, can fully take the place of words, and function as complete utterances in their own right. The relationship between these gestures and spoken language remains unclear. We used functional MRI to investigate whether these two forms of communication are processed by the same system in the human brain. Responses to symbolic gestures, to their spoken glosses (expressing the gestures' meaning in English), and to visually and acoustically matched control stimuli were compared in a randomized block design. General Linear Models (GLM) contrasts identified shared and unique activations and functional connectivity analyses delineated regional interactions associated with each condition. Results support a model in which bilateral modality-specific areas in superior and inferior temporal cortices extract salient features from vocal-auditory and gestural-visual stimuli respectively. However, both classes of stimuli activate a common, left-lateralized network of inferior frontal and posterior temporal regions in which symbolic gestures and spoken words may be mapped onto common, corresponding conceptual representations. We suggest that these anterior and posterior perisylvian areas, identified since the mid-19th century as the core of the brain's language system, are not in fact committed to language processing, but may function as a modality-independent semiotic system that plays a broader role in human communication, linking meaning with symbols whether these are words, gestures, images, sounds, or objects.


Assuntos
Gestos , Idioma , Processos Mentais , Rede Nervosa/fisiologia , Simbolismo , Mapeamento Encefálico , Feminino , Humanos
18.
Brain Res ; 1199: 62-73, 2008 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-18262172

RESUMO

The most marked leftward interhemispheric asymmetry of the human and great ape brain is present in a multisensory association area of the superior temporal gyrus. This cortical region, the planum temporale (part of Brodmann's area 22), has a cytoarchitectural homolog, area Tpt, in Old World monkeys. Reports in non-human primates vary widely in descriptions of area Tpt-associated indices of asymmetry at the gross anatomic level, but such asymmetry has not yet been considered at the cellular level. Here we assessed a mixed sex sample of perfusion-fixed adult macaque monkey brains to determine whether purported interhemispheric asymmetry of Tpt is manifested at the gross anatomic level by consideration of the length of the lateral sulcus. A separate sample was used to consider interhemispheric asymmetry by volumetric assessment of the cytoarchitectural profile of area Tpt. There was no significant hemispheric asymmetry of lateral sulcus length at the gross anatomic level. Previous studies that used endocasts may not have factored in opercularization of the sylvian point, shown here as being pronounced. Conversely, there was a significant leftward volumetric asymmetry of area Tpt at the cytoarchitectural level. Furthermore, the intrahemispheric profile of area Tpt topography was more varied than expected. These results indicate that leftward hemispheric asymmetry of these critical human language areas may have been based on a functional substrate with a long evolutionary history. The leftward cytoarchitectural asymmetry and highly varied topography of Tpt should be factored into investigative approaches that consider this region of the cerebral cortex.


Assuntos
Mapeamento Encefálico , Lateralidade Funcional/fisiologia , Macaca fascicularis/anatomia & histologia , Lobo Temporal/ultraestrutura , Análise de Variância , Animais , Processamento de Imagem Assistida por Computador , Modelos Lineares
19.
Anat Rec A Discov Mol Cell Evol Biol ; 287(1): 1128-41, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16215971

RESUMO

We have previously demonstrated that leftward asymmetry of the planum temporale (PT), a brain language area, was not unique to humans since a similar condition is present in great apes. Here we report on a related area in great apes, the planum parietale (PP). PP in humans has a rightward asymmetry with no correlation to the L>R PT, which indicates functional independence. The roles of the PT in human language are well known while PP is implicated in dyslexia and communication disorders. Since posterior bifurcation of the sylvian fissure (SF) is unique to humans and great apes, we used it to determine characteristics of its posterior ascending ramus, an indicator of the PP, in chimpanzee and orangutan brains. Results showed a human-like pattern of R>L PP (P = 0.04) in chimpanzees with a nonsignificant negative correlation of L>R PT vs. R>L PP (CC = -0.3; P = 0.39). In orangutans, SF anatomy is more variable, although PP was nonsignificantly R>L in three of four brains (P = 0.17). We have now demonstrated human-like hemispheric asymmetry of a second language-related brain area in great apes. Our findings persuasively support an argument for addition of a new component to the comparative neuroanatomic complex that defines brain language or polymodal communication areas. PP strengthens the evolutionary links that living great apes may offer to better understand the origins of these progressive parts of the brain. Evidence mounts for the stable expression of a neural foundation for language in species that we recently shared a common ancestor with.


Assuntos
Mapeamento Encefálico , Imageamento por Ressonância Magnética , Pan troglodytes/anatomia & histologia , Lobo Parietal/anatomia & histologia , Pongo pygmaeus/anatomia & histologia , Lobo Temporal/anatomia & histologia , Animais , Hominidae/fisiologia , Interpretação de Imagem Assistida por Computador/métodos , Masculino , Lobo Parietal/fisiologia , Lobo Temporal/fisiologia
20.
Acta Astronaut ; 56(9-12): 773-82, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15834996

RESUMO

The National Space Biomedical Research Institute (NSBRI) is supporting the National Aeronautics and Space Administration's (NASA) education mission through a comprehensive Education and Public Outreach Program (EPOP) that communicates the excitement and significance of space biology to schools, families, and lay audiences. The EPOP is comprised of eight academic institutions: Baylor College of Medicine, Massachusetts Institute of Technology, Morehouse School of Medicine, Mount Sinai School of Medicine, Texas A&M University, University of Texas Medical Branch Galveston, Rice University, and the University of Washington. This paper describes the programs and products created by the EPOP to promote space life science education in schools and among the general public. To date, these activities have reached thousands of teachers and students around the US and have been rated very highly.


Assuntos
Disciplinas das Ciências Biológicas/educação , Relações Comunidade-Instituição , Relações Públicas , Voo Espacial/educação , United States National Aeronautics and Space Administration , Currículo , Educação Continuada , Capacitação em Serviço , Pesquisa/educação , Estados Unidos , Universidades
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