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The burst firing of midbrain dopamine neurons releases a phasic dopamine signal that mediates reinforcement learning. At many synapses, however, high firing rates deplete synaptic vesicles (SVs), resulting in synaptic depression that limits release. What accounts for the increased release of dopamine by stimulation at high frequency? We find that adaptor protein-3 (AP-3) and its coat protein VPS41 promote axonal dopamine release by targeting vesicular monoamine transporter VMAT2 to the axon rather than dendrites. AP-3 and VPS41 also produce SVs that respond preferentially to high-frequency stimulation, independent of their role in axonal polarity. In addition, conditional inactivation of VPS41 in dopamine neurons impairs reinforcement learning, and this involves a defect in the frequency dependence of release rather than the amount of dopamine released. Thus, AP-3 and VPS41 promote the axonal polarity of dopamine release but enable learning by producing a distinct population of SVs tuned specifically to high firing frequency that confers the phasic release of dopamine.
Assuntos
Dopamina , Vesículas Sinápticas , Dopamina/metabolismo , Vesículas Sinápticas/metabolismo , Proteínas Vesiculares de Transporte de Monoamina/genética , Proteínas Vesiculares de Transporte de Monoamina/metabolismo , Axônios/metabolismo , Mesencéfalo/metabolismoRESUMO
BACKGROUND: The efficacy of insecticide-treated nets (ITNs) containing the insect growth regulator pyriproxyfen (PPF) and pyrethroid insecticides (PPF-ITNs) is being assessed in clinical trials to determine whether they provide greater protection from malaria than standard pyrethroid-treated ITNs in areas where mosquitoes are resistant to pyrethroids. Understanding the entomological mode of action of this new ITN class will aide interpretation of the results from these trials. METHODS: Anopheles gambiae sensu lato (s.l.) mosquitoes from a susceptible laboratory strain were exposed to PPF-treated netting 24 h, 6 h, and immediately prior to, or 24 h post blood feeding, and the impact on fecundity, fertility and longevity recorded. Pyrethroid-resistant populations were exposed to nets containing permethrin and PPF (PPF-ITNs) in cone bioassays and daily mortality recorded. Mosquitoes were also collected from inside houses pre- and post-distribution of PPF-ITNs in a clinical trial conduced in Burkina Faso; female An. gambiae s.l. were then assessed for fecundity and fertility. RESULTS: PPF exposure reduced the median adult lifespan of insecticide-susceptible mosquitoes by 4 to 5 days in all exposure times (p < 0.05) other than 6 h pre-blood meal and resulted in almost complete lifelong sterilization. The longevity of pyrethroid-resistant mosquitoes was also reduced by at least 5 days after exposure to PPF-ITNs compared to untreated nets, but was unaffected by exposure to standard pyrethroid only ITNs. A total of 386 blood-fed or gravid An. gambiae s.l. females were collected from five villages between 1 and 12 months before distribution of PPF-ITNs. Of these mosquitoes, 75% laid eggs and the remaining 25% appeared to have normal ovaries upon dissection. In contrast, only 8.6% of the 631 blood-fed or gravid An. gambiae s.l. collected post PPF-ITN distribution successfully oviposited; 276 (43.7%) did not oviposit but had apparently normal ovaries upon dissection, and 301 (47.7%) did not oviposit and had abnormal eggs upon dissection. Egg numbers were also significantly lower (average of 138/female prior distribution vs 85 post distribution, p < 0.05). CONCLUSION: Exposure to a mixture of PPF and pyrethroids on netting shortens the lifespan of mosquitoes and reduces reproductive output. Sterilization of vectors lasted at least one year under operational conditions. These findings suggest a longer effective lifespan of PPF-pyrethroid nets than reported previously.
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Anopheles , Aptidão Genética/efeitos dos fármacos , Resistência a Inseticidas , Mosquiteiros Tratados com Inseticida , Inseticidas , Controle de Mosquitos , Piridinas , Animais , Burkina Faso , Feminino , Longevidade/efeitos dos fármacos , Piretrinas/farmacologia , Reprodução/efeitos dos fármacosRESUMO
An amendment to this paper has been published and can be accessed via the original article.
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BACKGROUND: With over 800 million cases globally, campylobacteriosis is a major cause of food borne disease. In temperate climates incidence is highly seasonal but the underlying mechanisms are poorly understood, making human disease control difficult. We hypothesised that observed disease patterns reflect complex interactions between weather, patterns of human risk behaviour, immune status and level of food contamination. Only by understanding these can we find effective interventions. METHODS: We analysed trends in human Campylobacter cases in NE England from 2004 to 2009, investigating the associations between different risk factors and disease using time-series models. We then developed an individual-based (IB) model of risk behaviour, human immunological responses to infection and environmental contamination driven by weather and land use. We parameterised the IB model for NE England and compared outputs to observed numbers of reported cases each month in the population in 2004-2009. Finally, we used it to investigate different community level disease reduction strategies. RESULTS: Risk behaviours like countryside visits (t = 3.665, P < 0.001 and t = - 2.187, P = 0.029 for temperature and rainfall respectively), and consumption of barbecued food were strongly associated with weather, (t = 3.219, P = 0.002 and t = 2.015, P = 0.045 for weekly average temperature and average maximum temperature respectively) and also rain (t = 2.254, P = 0.02527). This suggests that the effect of weather was indirect, acting through changes in risk behaviour. The seasonal pattern of cases predicted by the IB model was significantly related to observed patterns (r = 0.72, P < 0.001) indicating that simulating risk behaviour could produce the observed seasonal patterns of cases. A vaccination strategy providing short-term immunity was more effective than educational interventions to modify human risk behaviour. Extending immunity to 1 year from 20 days reduced disease burden by an order of magnitude (from 2412-2414 to 203-309 cases per 50,000 person-years). CONCLUSIONS: This is the first interdisciplinary study to integrate environment, risk behaviour, socio-demographics and immunology to model Campylobacter infection, including pathways to mitigation. We conclude that vaccination is likely to be the best route for intervening against campylobacteriosis despite the technical problems associated with understanding both the underlying human immunology and genetic variation in the pathogen, and the likely cost of vaccine development.
Assuntos
Comportamento , Infecções por Campylobacter/epidemiologia , Clima , Efeitos Psicossociais da Doença , Meio Ambiente , Modelos Biológicos , Estações do Ano , Animais , Galinhas , Inglaterra/epidemiologia , Humanos , Chuva , TemperaturaRESUMO
BACKGROUND: Long-lasting insecticidal nets (LLINs) treated with pyrethroids are the foundation of malaria control in sub-Saharan Africa. Rising pyrethroid resistance in vectors, however, has driven the development of alternative net formulations. Here the durability of polyethylene nets with a novel combination of a pyrethroid, permethrin, and the insect juvenile hormone mimic, pyriproxyfen (PPF), compared to a standard permethrin LLIN, was assessed in rural Burkina Faso. METHODS: A compound-randomized controlled trial was completed in two villages. In one village 326 of the PPF-permethrin nets (Olyset Duo) and 327 standard LLINs (Olyset) were distributed to assess bioefficacy. In a second village, 170 PPF-permethrin nets and 376 LLINs were distributed to assess survivorship. Nets were followed at 6-monthly intervals for 3 years. Bioefficacy was assessed by exposing permethrin-susceptible and resistant Anopheles gambiae sensu lato mosquito strains to standard World Health Organization (WHO) cone and tunnel tests with impacts on fertility measured in the resistant strain. Insecticide content was measured using high-performance liquid chromatography. LLIN survivorship was recorded with a questionnaire and assessed by comparing the physical integrity using the proportionate hole index (pHI). RESULTS: The PPF-permethrin net met WHO bioefficacy criteria (≥ 80% mortality or ≥ 95% knockdown) for the first 18 months, compared to 6 months for the standard LLIN. Mean mosquito mortality for PPF-permethrin nets, across all time points, was 8.6% (CI 2.6-14.6%) higher than the standard LLIN. Fertility rates were reduced after PPF-permethrin net exposure at 1-month post distribution, but not later. Permethrin content of both types of nets remained within the target range of 20 g/kg ± 25% for 242/248 nets tested. The pyriproxyfen content of PPF-permethrin nets declined by 54%, from 10.4 g/kg (CI 10.2-10.6) to 4.7 g/kg (CI 3.5-6.0, p < 0.001) over 36 months. Net survivorship was poor, with only 13% of PPF-permethrin nets and 12% of LLINs still present in the original household after 36 months. There was no difference in the fabric integrity or survivorship between the two net types. CONCLUSION: The PPF-permethrin net, Olyset Duo, met or exceeded the performance of the WHO-recommended standard LLIN (Olyset) in the current study but both net types failed the 3-year WHO bioefficacy criteria.
Assuntos
Anopheles , Mosquiteiros Tratados com Inseticida/estatística & dados numéricos , Inseticidas , Controle de Mosquitos , Mosquitos Vetores , Permetrina , Piridinas , Animais , Burkina Faso , Malária/prevenção & controleRESUMO
The burst firing of midbrain dopamine neurons releases a phasic dopamine signal that mediates reinforcement learning. At many synapses, however, high firing rates deplete synaptic vesicles (SVs), resulting in synaptic depression that limits release. What accounts for the increased release of dopamine by stimulation at high frequency? We find that adaptor protein-3 (AP-3) and its coat protein VPS41 promote axonal dopamine release by targeting vesicular monoamine transporter VMAT2 to the axon rather than dendrites. AP-3 and VPS41 also produce SVs that respond preferentially to high frequency stimulation, independent of their role in axonal polarity. In addition, conditional inactivation of VPS41 in dopamine neurons impairs reinforcement learning, and this involves a defect in the frequency dependence of release rather than the amount of dopamine released. Thus, AP-3 and VPS41 promote the axonal polarity of dopamine release but enable learning by producing a novel population of SVs tuned specifically to high firing frequency that confers the phasic release of dopamine.
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Inherited myelopathies are a small, but important subset of diseases that cause dysfunction of the spinal cord. Manifestations can include various combinations of signs and symptoms, including disturbance of gait, spasticity, paraplegia, amyotrophy, sensory loss, and urinary sphincter dysfunction. These diseases can be divided into classes that include (1) distal axonopathies-exemplified by hereditary spastic paraplegia, (2) motor neuron diseases including familial amyotrophic lateral sclerosis and spinal muscular atrophy, (3) inborn errors of metabolism such as adrenomyeloneuropathy, and (4) other inherited diseases with myelopathy as part of their spectrum of manifestations. Although the inherited myelopathies are relatively rare diseases, knowledge of them and their manifestations is important for the physician faced with a patient with myelopathy, particularly if there are similarly affected individuals in the patient's family. In addition, understanding the pathophysiologic underpinnings of these diseases provides insight into the molecular biology of the nervous system and provides a gateway toward developing treatments for these diseases.
Assuntos
Doenças da Medula Espinal/congênito , Doenças da Medula Espinal/fisiopatologia , Esclerose Lateral Amiotrófica/diagnóstico , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/fisiopatologia , Predisposição Genética para Doença/genética , Humanos , Erros Inatos do Metabolismo/diagnóstico , Erros Inatos do Metabolismo/genética , Erros Inatos do Metabolismo/fisiopatologia , Atrofia Muscular Espinal/diagnóstico , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/fisiopatologia , Paraplegia Espástica Hereditária/diagnóstico , Paraplegia Espástica Hereditária/fisiopatologia , Doenças da Medula Espinal/diagnósticoRESUMO
Indoor residual spraying (IRS) of insecticides is a major vector control strategy for malaria prevention. We evaluated the impact of a single round of IRS with the organophosphate, pirimiphos-methyl (Actellic 300CS), on entomological and parasitological parameters of malaria in Migori County, western Kenya in 2017, in an area where primary vectors are resistant to pyrethroids but susceptible to the IRS compound. Entomological monitoring was conducted by indoor CDC light trap, pyrethrum spray catches (PSC) and human landing collection (HLC) before and after IRS. The residual effect of the insecticide was assessed monthly by exposing susceptible An. gambiae s.s. Kisumu strain to sprayed surfaces in cone assays and measuring mortality at 24 hours. Malaria case burden data were extracted from laboratory records of four health facilities within the sprayed area and two adjacent unsprayed areas. IRS was associated with reductions in An. funestus numbers in the intervention areas compared to non-intervention areas by 88% with light traps (risk ratio [RR] 0.12, 95% CI 0.07-0.21, p < 0.001) and 93% with PSC collections (RR = 0.07, 0.03-0.17, p < 0.001). The corresponding reductions in the numbers of An. arabiensis collected by PSC were 69% in the intervention compared to the non-intervention areas (RR = 0.31, 0.14-0.68, p = 0.006), but there was no significant difference with light traps (RR = 0.45, 0.21-0.96, p = 0.05). Before IRS, An. funestus accounted for over 80% of Anopheles mosquitoes collected by light trap and PSC in all sites. After IRS, An. arabiensis accounted for 86% of Anopheles collected by PSC and 66% by CDC light trap in the sprayed sites while the proportion in non-intervention sites remained unchanged. No sporozoite infections were detected in intervention areas after IRS and biting rates by An. funestus were reduced to near zero. Anopheles funestus and An. arabiensis were fully susceptible to pirimiphos-methyl and resistant to pyrethroids. The residual effect of Actellic 300CS lasted ten months on mud and concrete walls. Malaria case counts among febrile patients within IRS areas was lower post- compared to pre-IRS by 44%, 65% and 47% in Rongo, Uriri and Nyatike health facilities respectively. A single application of IRS with Actellic 300CS in Migori County provided ten months protection and resulted in the near elimination of the primary malaria vector An. funestus and a corresponding reduction of malaria case count among out-patients. The impact was less on An. arabiensis, most likely due to their exophilic nature.
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Controle de Insetos , Inseticidas/administração & dosagem , Malária/prevenção & controle , Malária/parasitologia , Compostos Organotiofosforados/administração & dosagem , Animais , Vetores de Doenças , Entomologia , Geografia Médica , Humanos , Controle de Insetos/métodos , Quênia/epidemiologia , Malária/epidemiologia , Malária/transmissão , Estações do AnoRESUMO
The United Kingdom, as in most countries using intensive dairy management programmes, is facing serious challenges in terms of dairy cow fertility, as highlighted by a rapidly increasing calving interval (CI). A mechanistic, mathematical model is described that predicts the size of the future national dairy herd required to supply domestic requirements and its inherent sustainability in terms of production of replacement female numbers. The results from the model suggest that continuing use of current management strategies may result in the national dairy herd being unsustainable due to increasing CI and reduced fertility in as few as 10years. Adoption of nutritional, endocrine and genetic techniques that increase fertility can effectively and rapidly reverse this trend and reduce the required size of the national herd, thereby reducing methane emissions from dairy production.
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Fertilidade/genética , Fertilidade/fisiologia , Modelos Biológicos , Fenômenos Fisiológicos da Nutrição Animal , Animais , Cruzamento , Bovinos , Doenças dos Bovinos/diagnóstico , Indústria de Laticínios/economia , Indústria de Laticínios/tendências , Dieta/veterinária , Feminino , Masculino , Gravidez , Sensibilidade e Especificidade , Fatores de Tempo , Reino UnidoRESUMO
Adenylyl cyclase types 1 (AC1) and 8 (AC8), the two major calmodulin-stimulated adenylyl cyclases in the brain, couple NMDA receptor activation to cAMP signaling pathways. Cyclic AMP signaling pathways are important for many brain functions, such as learning and memory, drug addiction, and development. Here we show that wild-type, AC1, AC8, or AC1&8 double knockout (DKO) mice were indistinguishable in tests of acute pain, whereas behavioral responses to peripheral injection of two inflammatory stimuli, formalin and complete Freund's adjuvant, were reduced or abolished in AC1&8 DKO mice. AC1 and AC8 are highly expressed in the anterior cingulate cortex (ACC), and contribute to inflammation-induced activation of CREB. Intra-ACC administration of forskolin rescued behavioral allodynia defective in the AC1&8 DKO mice. Our studies suggest that AC1 and AC8 in the ACC selectively contribute to behavioral allodynia.
Assuntos
Adenilil Ciclases/deficiência , Encéfalo/enzimologia , Calmodulina/metabolismo , AMP Cíclico/metabolismo , Hiperalgesia/genética , Vias Neurais/enzimologia , Dor/genética , Adenilil Ciclases/genética , Animais , Comportamento Animal/fisiologia , Encéfalo/fisiopatologia , AMP Cíclico/análogos & derivados , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Inibidores Enzimáticos/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Adjuvante de Freund , Hiperalgesia/enzimologia , Hiperalgesia/fisiopatologia , Masculino , Camundongos , Camundongos Knockout , Vias Neurais/fisiopatologia , Dor/enzimologia , Dor/fisiopatologia , Medição da Dor , RNA Mensageiro/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismoRESUMO
Background: Campylobacteriosis is a major cause of gastroenteritis in the UK, and although 70% of cases are associated with food sources, the remainder are probably associated with wider environmental exposure. Methods: In order to investigate wider environmental transmission, we conducted a spatio-temporal analysis of the association of human cases of Campylobacter in the Tyne catchment with weather, climate, hydrology and land use. A hydrological model was used to predict surface-water flow in the Tyne catchment over 5 years. We analysed associations between population-adjusted Campylobacter case rate and environmental factors hypothesized to be important in disease using a two-stage modelling framework. First, we investigated associations between temporal variation in case rate in relation to surface-water flow, temperature, evapotranspiration and rainfall, using linear mixed-effects models. Second, we used the random effects for the first model to quantify how spatial variation in static landscape features of soil and land use impacted on the likely differences between subcatchment associations of case rate with the temporal variables. Results: Population-adjusted Campylobacter case rates were associated with periods of high predicted surface-water flow, and during above average temperatures. Subcatchments with cattle on stagnogley soils, and to a lesser extent sheep plus cattle grazing, had higher Campylobacter case rates. Conclusions: Areas of stagnogley soils with mixed livestock grazing may be more vulnerable to both Campylobacter spread and exposure during periods of high rainfall, with resultant increased risk of human cases of the disease.
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Infecções por Campylobacter/epidemiologia , Infecções por Campylobacter/transmissão , Exposição Ambiental , Animais , Campylobacter/isolamento & purificação , Humanos , Gado/microbiologia , Chuva , Microbiologia do Solo , Análise Espaço-Temporal , Temperatura , Reino Unido/epidemiologia , Tempo (Meteorologia)RESUMO
Dominant mutations in leucine-rich repeat kinase 2 (LRRK2) produce the most common inherited form of Parkinson's disease (PD) but the function of LRRK2 remains poorly understood. The presynaptic role of multiple genes linked to PD including α-synuclein (α-syn) has suggested that LRRK2 may also influence neurotransmitter release, a possibility supported by recent work. However, the use of disease-associated mutants that cause toxicity complicates the analysis. To determine whether LRRK2 normally influences the synaptic vesicle, we have now used a combination of imaging and electrophysiology to study LRRK2 knockout (KO) mice. Surprisingly, we find that in hippocampal (generally excitatory) neurons, the loss of LRRK2 does not affect synaptic vesicle exocytosis, endocytosis or the mobility of α-syn. Double KO (DKO) mice lacking LRRK1 as well as LRRK2 also show no defect in transmitter release by hippocampal neurons. However, in striatal neurons, which express LRRK2 at higher levels, the loss of LRRK2 leads to modest acceleration of synaptic vesicle endocytosis. Thus, endogenous LRRK2 normally slows synaptic vesicle recycling at striatal terminals.
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The importance of the cAMP signaling pathway in the modulation of ethanol sensitivity has been suggested by studies in organisms from Drosophila melanogaster to man. However, the involvement of specific isoforms of adenylyl cyclase (AC), the molecule that converts ATP to cAMP, has not been systemically determined in vivo. Because AC1 and AC8 are the only AC isoforms stimulated by calcium, and ethanol modulates calcium flux by the NMDA receptor, we hypothesized that these ACs would be important in the neural response to ethanol. AC1 knock-out (KO) mice and double knock-out (DKO) mice with genetic deletion of both AC1 and AC8 display substantially increased sensitivity to ethanol-induced sedation compared with wild-type (WT) mice, whereas AC8 KO mice are only minimally more sensitive. In contrast, AC8 KO and DKO mice, but not AC1 KO mice, demonstrate decreased voluntary ethanol consumption compared with WT mice. DKO mice do not display increased sleep time compared with WT mice after administration of ketamine or pentobarbital, indicating that the mechanism of enhanced ethanol sensitivity in these mice is likely distinct from the antagonism of ethanol of the NMDA receptor and potentiation of the GABA(A) receptor. Ethanol does not enhance calcium-stimulated AC activity, but the ethanol-induced phosphorylation of a discrete subset of protein kinase A (PKA) substrates is compromised in the brains of DKO mice. These results indicate that the unique activation of PKA signaling mediated by the calcium-stimulated ACs is an important component of the neuronal response to ethanol.
Assuntos
Adenilil Ciclases/metabolismo , Cálcio/farmacologia , Depressores do Sistema Nervoso Central/farmacologia , Etanol/farmacologia , Neurônios/efeitos dos fármacos , Adenilil Ciclases/deficiência , Análise de Variância , Animais , Ataxia/fisiopatologia , Comportamento Animal , Western Blotting/métodos , Depressores do Sistema Nervoso Central/sangue , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Maleato de Dizocilpina/farmacologia , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Etanol/sangue , Antagonistas de Aminoácidos Excitatórios/farmacologia , Preferências Alimentares/efeitos dos fármacos , Agonistas GABAérgicos/farmacologia , Isoxazóis/farmacologia , Ketamina/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/fisiologia , Pentobarbital/farmacologia , Fosforilação/efeitos dos fármacos , Desempenho Psicomotor/efeitos dos fármacos , Desempenho Psicomotor/fisiologia , Quinina/farmacologia , Tempo de Reação/efeitos dos fármacos , Reflexo/efeitos dos fármacos , Sacarina/farmacologia , Sono/efeitos dos fármacos , Sono/genéticaRESUMO
Fetal alcohol exposure results in cognitive and neurobehavioral deficits, but the effects of modifying genetic loci on the severity of these sequelas have not been well characterized. Although the cAMP signaling pathway has been shown to be an important modulator of ethanol sensitivity in adult mice, its potential role in modulating ethanol-induced neurodegeneration has not been examined. Adenylyl cyclases (ACs) 1 and 8 produce cAMP in response to intracellular calcium elevation and modulate several aspects of neuronal function, including ethanol sensitivity. AC1 and AC8 are expressed widely throughout the brain of neonatal mice, and genetic deletion of both AC1 and AC8 in double-knock-out (DKO) mice enhances ethanol-induced neurodegeneration in the brains of neonatal mice. In addition, ethanol treatment induces significantly greater levels of caspase-3 activation in the brains of DKO mice compared with wild-type (WT) mice, reflecting higher numbers of apoptotic neurons. Administration of the NMDA receptor antagonist MK801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine hydrogen maleate] or the GABA(A) receptor potentiator phenobarbital, which mimics components of the effects of ethanol on neurons, results in significantly greater neurodegeneration in the brains of neonatal DKO mice than WT mice. Furthermore, loss of a single calcium-stimulated AC isoform potentiates neurodegeneration after administration of ethanol, MK801, or phenobarbital. In contrast, the levels of physiological cell death, death after hypoxia/ischemia, and excitotoxic cell death are not increased in the brains of DKO mice. Thus, AC1 and AC8 are critical modulators of neurodegeneration induced by activity blockade in the neonatal brain and represent genetic loci that may potentially modify the severity of fetal alcohol syndrome.
Assuntos
Adenilil Ciclases/metabolismo , Encéfalo/efeitos dos fármacos , Cálcio/farmacologia , Etanol , Doenças Neurodegenerativas/induzido quimicamente , Anilidas/metabolismo , Animais , Animais Recém-Nascidos , Comportamento Animal , Western Blotting/métodos , Encéfalo/crescimento & desenvolvimento , Encéfalo/patologia , Caspase 3 , Caspases/metabolismo , Maleato de Dizocilpina/farmacologia , Relação Dose-Resposta a Droga , Interações Medicamentosas , Etanol/sangue , Moduladores GABAérgicos/farmacologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/patologia , Hipocampo/fisiopatologia , Hipóxia/metabolismo , Hipóxia/patologia , Hibridização In Situ/métodos , Técnicas In Vitro , Camundongos , Camundongos Endogâmicos C57BL , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Neurônios/metabolismo , Neurônios/fisiologia , Fármacos Neuroprotetores/farmacologia , Oligopeptídeos/metabolismo , Fenobarbital/farmacologia , Coloração pela Prata/métodos , Fatores de TempoRESUMO
The regulated release of polypeptides has a central role in physiology, behavior, and development, but the mechanisms responsible for production of the large dense core vesicles (LDCVs) capable of regulated release have remained poorly understood. Recent work has implicated cytosolic adaptor protein AP-3 in the recruitment of LDCV membrane proteins that confer regulated release. However, AP-3 in mammals has been considered to function in the endolysosomal pathway and in the biosynthetic pathway only in yeast. We now find that the mammalian homolog of yeast VPS41, a member of the homotypic fusion and vacuole protein sorting (HOPS) complex that delivers biosynthetic cargo to the endocytic pathway in yeast, promotes LDCV formation through a common mechanism with AP-3, indicating a conserved role for these proteins in the biosynthetic pathway. VPS41 also self-assembles into a lattice, suggesting that it acts as a coat protein for AP-3 in formation of the regulated secretory pathway.
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Proteínas de Ligação a DNA/metabolismo , Drosophila melanogaster/metabolismo , Exocitose/fisiologia , Biogênese de Organelas , Via Secretória/fisiologia , Fatores de Transcrição/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Animais , Células COS , Chlorocebus aethiops , DNA Liase (Sítios Apurínicos ou Apirimidínicos) , Proteínas de Ligação a DNA/genética , Proteínas de Drosophila , Drosophila melanogaster/genética , Endossomos/metabolismo , Humanos , Fusão de Membrana , Proteínas de Membrana/metabolismo , Células PC12 , Transporte Proteico , Ratos , Vesículas Secretórias/metabolismo , Fatores de Transcrição/genética , Proteínas Vesiculares de Transporte de Monoamina/metabolismo , Proteínas de Transporte Vesicular/genéticaRESUMO
Paroxysmal kinesigenic dyskinesia with infantile convulsions (PKD/IC) is an episodic movement disorder with autosomal-dominant inheritance and high penetrance, but the causative genetic mutation is unknown. We have now identified four truncating mutations involving the gene PRRT2 in the vast majority (24/25) of well-characterized families with PKD/IC. PRRT2 truncating mutations were also detected in 28 of 78 additional families. PRRT2 encodes a proline-rich transmembrane protein of unknown function that has been reported to interact with the t-SNARE, SNAP25. PRRT2 localizes to axons but not to dendritic processes in primary neuronal culture, and mutants associated with PKD/IC lead to dramatically reduced PRRT2 levels, leading ultimately to neuronal hyperexcitability that manifests in vivo as PKD/IC.
Assuntos
Distonia/complicações , Distonia/genética , Proteínas de Membrana/genética , Mutação/genética , Proteínas do Tecido Nervoso/genética , Convulsões/complicações , Convulsões/genética , Alelos , Sequência de Aminoácidos , Animais , Sistema Nervoso Central/metabolismo , Segregação de Cromossomos/genética , Variações do Número de Cópias de DNA/genética , Feminino , Genoma Humano/genética , Células HEK293 , Humanos , Masculino , Proteínas de Membrana/química , Camundongos , Dados de Sequência Molecular , Proteínas Mutantes/metabolismo , Proteínas do Tecido Nervoso/química , Linhagem , Fenótipo , Ligação Proteica/genética , Ratos , Alinhamento de Sequência , Análise de Sequência de DNA , Especificidade da Espécie , Proteína 25 Associada a Sinaptossoma/metabolismoRESUMO
BACKGROUND: The Ca2+-stimulated adenylyl cyclases (ACs), AC1 and AC8, are key components of long-term memory processing. AC1 and AC8 double knockout mice (Adcy1(-/-)Adcy8(-/-); DKO) display impaired fear memory processing; the mechanism of this impairment is largely unknown. METHODOLOGY/PRINCIPAL FINDINGS: We hypothesize that the Ca2+-stimulated ACs modulate long-lasting transcriptional changes essential for fear memory consolidation and maintenance. Here, we report a genome-wide study of gene expression changes associated with conditioned fear (CF) memory in wild-type and DKO mice to identify AC-dependent gene regulatory changes that occur in the amygdala and hippocampus at baseline and different time points after CF learning. We observed an overall decrease in transcriptional changes in DKO mice across all time points, but most strikingly, at periods when memory consolidation and retention should be occurring. Further, we identified a shared set of transcription factor binding sites in genes upregulated in wild-type mice that were associated with downregulated genes in DKO mice. To prove the temporal and regional importance of AC activity on different stages of memory processing, the tetracycline-off system was used to produce mice with forebrain-specific inducible expression of AC8 on a DKO background. CF behavioral results reveal that adult restoration of AC8 activity in the forebrain is sufficient for intact learning, while cessation of this expression at any time point across learning causes memory deficits. CONCLUSIONS/SIGNIFICANCE: Overall, these studies demonstrate that the Ca2+-stimulated ACs contribute to the formation and maintenance of fear memory by a network of long-term transcriptional changes.
Assuntos
Adenilil Ciclases/metabolismo , Cálcio/metabolismo , Medo , Regulação da Expressão Gênica , Memória , Animais , Western Blotting , Imuno-Histoquímica , Camundongos , Família Multigênica , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
BACKGROUND: Although ethanol exerts widespread action in the brain, only recently has progress been made in understanding the specific events occurring at the synapse during ethanol exposure. Mice deficient in the calcium-stimulated adenylyl cyclases, AC1 and AC8 (DKO), demonstrate increased sedation duration and impaired phosphorylation by protein kinase A (PKA) following acute ethanol treatment. While not direct targets for ethanol, we hypothesize that these cyclases initiate a homeostatic presynaptic response by PKA to reactivate neurons from ethanol-mediated inhibition. METHODOLOGY/PRINCIPAL FINDINGS: Here, we have used phosphoproteomic techniques and identified several presynaptic proteins that are phosphorylated in the brains of wild type mice (WT) after ethanol exposure, including synapsin, a known PKA target. Phosphorylation of synapsins I and II, as well as phosphorylation of non-PKA targets, such as, eukaryotic elongation factor-2 (eEF-2) and dynamin is significantly impaired in the brains of DKO mice. This deficit is primarily driven by AC1, as AC1-deficient, but not AC8-deficient mice also demonstrate significant reductions in phosphorylation of synapsin and eEF-2 in cortical and hippocampal tissues. DKO mice have a reduced pool of functional recycling vesicles and fewer active terminals as measured by FM1-43 uptake compared to WT controls, which may be a contributing factor to the impaired presynaptic response to ethanol treatment. CONCLUSIONS/SIGNIFICANCE: These data demonstrate that calcium-stimulated AC-dependent PKA activation in the presynaptic terminal, primarily driven by AC1, is a critical event in the reactivation of neurons following ethanol-induced activity blockade.