RESUMO
In multiple neurodevelopmental and neurodegenerative disorders, endosomal changes correlate with changes in exosomes. We examined this linkage in the brain of mice that received cocaine injections for two weeks starting at 2.5 months of age. Cocaine caused a decrease in the number of both neuronal early and late endosomes and exosomes in the brains of male but not female mice. The response to cocaine in ovariectomized females mirrored male, demonstrating that these sex-differences in response to cocaine are driven by hormonal differences. Moreover, cocaine increased the amount of α-synuclein per exosome in the brain of females but did not affect exosomal α-synuclein content in the brain of males, a sex-difference eliminated by ovariectomy. Enhanced packaging of α-synuclein into female brain exosomes with the potential for propagation of pathology throughout the brain suggests a mechanism for the different response of females to chronic cocaine exposure as compared to males.
Assuntos
Cocaína , Exossomos , Animais , Cocaína/farmacologia , Endossomos , Feminino , Masculino , Camundongos , Neurônios/patologia , alfa-SinucleínaRESUMO
Cocaine is a highly addictive stimulant with diverse effects on physiology. Recent studies indicate the involvement of extracellular vesicles (EVs) secreted by neural cells in the cocaine addiction process. It is hypothesized that cocaine affects secretion levels of EVs and their cargos, resulting in modulation of synaptic transmission and plasticity related to addiction physiology and pathology. Lipids present in EVs are important for EV formation and for intercellular lipid exchange that may trigger physiological and pathological responses, including neuroplasticity, neurotoxicity, and neuroinflammation. Specific lipids are highly enriched in EVs compared to parent cells, and recent studies suggest the involvement of various lipids in drug-induced synaptic plasticity during the development and maintenance of addiction processes. Therefore, we examined interstitial small EVs isolated from the brain of mice treated with either saline or cocaine, focusing on the effects of cocaine on the lipid composition of EVs. We demonstrate that 12 days of noncontingent repeated cocaine (10 mg/kg) injections to mice, which induce locomotor sensitization, cause lipid composition changes in brain EVs of male mice as compared with saline-injected controls. The most prominent change is the elevation of GD1a ganglioside in brain EVs of males. However, cocaine does not affect the EV lipid profiles of the brain in female mice. Understanding the relationship between lipid composition in EVs and vulnerability to cocaine addiction may provide insight into novel targets for therapies for addiction.
Assuntos
Encéfalo/efeitos dos fármacos , Cocaína/toxicidade , Inibidores da Captação de Dopamina/toxicidade , Vesículas Extracelulares/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Caracteres Sexuais , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Cocaína/administração & dosagem , Inibidores da Captação de Dopamina/administração & dosagem , Vesículas Extracelulares/metabolismo , Vesículas Extracelulares/patologia , Feminino , Injeções Intraperitoneais , Metabolismo dos Lipídeos/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Mitochondrial dysfunction is an established hallmark of aging and neurodegenerative disorders such as Down syndrome (DS) and Alzheimer's disease (AD). Using a high-resolution density gradient separation of extracellular vesicles (EVs) isolated from murine and human DS and diploid control brains, we identify and characterize a previously unknown population of double-membraned EVs containing multiple mitochondrial proteins distinct from previously described EV subtypes, including microvesicles and exosomes. We term these newly identified mitochondria-derived EVs "mitovesicles." We demonstrate that brain-derived mitovesicles contain a specific subset of mitochondrial constituents and that their levels and cargo are altered during pathophysiological processes where mitochondrial dysfunction occurs, including in DS. The development of a method for the selective isolation of mitovesicles paves the way for the characterization in vivo of biological processes connecting EV biology and mitochondria dynamics and for innovative therapeutic and diagnostic strategies.
Assuntos
Doença de Alzheimer , Síndrome de Down , Exossomos , Vesículas Extracelulares , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Animais , Síndrome de Down/genética , Síndrome de Down/metabolismo , Exossomos/metabolismo , Vesículas Extracelulares/metabolismo , Humanos , CamundongosRESUMO
The mixed random processes of the first order autoregressive process (AR(1)) and white noise have been proved to provide a good approximation of baseline noise in a variety of analytical instruments, and may therefore be useful for estimating precision profiles. This study aims to examine a recently proposed autocorrelation method for estimating three noise parameters involved in the mixed processes (two for AR(1) and one for white noise) of HPLC, which can then be used to calculate the precision profile. This chemometric method was applied to repeatability evaluations of estriol determination using HPLC with UV detection (HPLC-UV). The relative standard deviations (RSDs) of peak area measurements for 5.0 mg/L estriol were observed to be 1.42% for the autocorrelation method and 1.63% for actual repeated measurements of real samples (n = 6). The theoretical RSDs of the autocorrelation method fell within the 95% confidence intervals of the repeated measurements. It is found that the noise parameters are obtained from real chromatographic baseline via the autocorrelation method. Moreover, the instrumental detection limit of estriol based on ISO 11843 was obtained from the precision profile (plot of RSD of measurements against concentration). This is the first paper to describe the autocorrelation method is a practically useful technique for evaluating the precision profile of HPLC-UV analyses without recourse to the repeated measurements of real samples.
Assuntos
Estriol/análise , Flavonoides/análise , Cromatografia Líquida de Alta Pressão , Espectrofotometria UltravioletaRESUMO
Microglial activation followed by neuroinflammation is a defense mechanism of the brain to eliminate harmful endogenous and exogenous materials including pathogens and damaged tissues, while excessive or chronic neuroinflammation may cause or exacerbate neurodegeneration observed in brain injuries and neurodegenerative diseases. Depending on conditions/environments during activation, microglia acquire distinct phenotypes, such as pro-inflammatory, anti-inflammatory, and disease-associated phenotypes, and show their ability to phagocytose various objects and produce pro-and anti-inflammatory mediators. Prevention of excessive inflammation by regulating the microglia's pro/anti-inflammatory balance is important for alleviating progression of brain injuries and diseases. Among many factors involved in the regulation of microglial phenotypes, cellular energy status plays an important role. Adenosine monophosphate-activated protein kinase (AMPK), which serves as a master sensor and regulator of energy balance, is considered a candidate molecule. Accumulating evidence from adult rodent studies indicates that AMPK activation promotes anti-inflammatory responses in microglia exposed to danger signals or various stressors mainly through inhibition of the nuclear factor κB (NF-κB) signaling and activation of the nuclear factor erythroid-2-related factor-2 (Nrf2) pathway. However, AMPK activation in neurons exposed to stressors/insults may exacerbate neuronal damage if AMPK activation is excessive or prolonged. While AMPK affects microglial activation states and neuronal cell survival rates in both the adult and the developing brain, studies in the developing brain are still scarce, even though activated AMPK is highly expressed especially in the neonatal brain. More in depth studies in the developing brain are important, because neuroinflammation/neurodegeneration occurred during development can result in long-lasting brain damage.
Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Encéfalo/metabolismo , Inflamação/metabolismo , Microglia/metabolismo , Doenças Neurodegenerativas/metabolismo , Animais , Encéfalo/patologia , Humanos , Inflamação/patologia , Microglia/patologia , Doenças Neurodegenerativas/patologia , Transdução de Sinais/fisiologiaRESUMO
Reduction in parvalbumin-positive (PV+) interneurons is observed in adult mice exposed to ethanol at postnatal day 7 (P7), a late gestation fetal alcohol spectrum disorder model. To evaluate whether PV+ cells are lost, or PV expression is reduced, we quantified PV+ and associated perineuronal net (PNN)+ cell densities in barrel cortex. While PNN+ cell density was not reduced by P7 ethanol, PV cell density decreased by 25% at P90 with no decrease at P14. PNN+ cells in controls were virtually all PV+, whereas more than 20% lacked PV in ethanol-treated adult animals. P7 ethanol caused immediate apoptosis in 10% of GFP+ cells in G42 mice, which express GFP in a subset of PV+ cells, and GFP+ cell density decreased by 60% at P90 without reduction at P14. The ethanol effect on PV+ cell density was attenuated by lithium treatment at P7 or at P14-28. Thus, reduced PV+ cell density may be caused by disrupted cell maturation, in addition to acute apoptosis. This effect may be regionally specific: in the dentate gyrus, P7 ethanol reduced PV+ cell density by 70% at P14 and both PV+ and PNN+ cell densities by 50% at P90, and delayed lithium did not alleviate ethanol's effect.
Assuntos
Giro Denteado/efeitos dos fármacos , Giro Denteado/crescimento & desenvolvimento , Etanol/administração & dosagem , Matriz Extracelular/efeitos dos fármacos , Interneurônios/efeitos dos fármacos , Córtex Somatossensorial/efeitos dos fármacos , Córtex Somatossensorial/crescimento & desenvolvimento , Animais , Apoptose/efeitos dos fármacos , Contagem de Células , Matriz Extracelular/patologia , Feminino , Interneurônios/química , Interneurônios/patologia , Lítio/administração & dosagem , Masculino , Camundongos Endogâmicos C57BL , Parvalbuminas/análiseRESUMO
In addition to being the greatest genetic risk factor for Alzheimer's disease, expression of the É4 allele of apolipoprotein E can lead to cognitive decline during ageing that is independent of Alzheimer's amyloid-ß and tau pathology. In human post-mortem tissue and mouse models humanized for apolipoprotein E, we examined the impact of apolipoprotein E4 expression on brain exosomes, vesicles that are produced within and secreted from late-endocytic multivesicular bodies. Compared to humans or mice homozygous for the risk-neutral É3 allele we show that the É4 allele, whether homozygous or heterozygous with an É3 allele, drives lower exosome levels in the brain extracellular space. In mice, we show that the apolipoprotein E4-driven change in brain exosome levels is age-dependent: while not present at age 6 months, it is detectable at 12 months of age. Expression levels of the exosome pathway regulators tumor susceptibility gene 101 (TSG101) and Ras-related protein Rab35 (RAB35) were found to be reduced in the brain at the protein and mRNA levels, arguing that apolipoprotein E4 genotype leads to a downregulation of exosome biosynthesis and release. Compromised exosome production is likely to have adverse effects, including diminishing a cell's ability to eliminate materials from the endosomal-lysosomal system. This reduction in brain exosome levels in 12-month-old apolipoprotein E4 mice occurs earlier than our previously reported brain endosomal pathway changes, arguing that an apolipoprotein E4-driven failure in exosome production plays a primary role in endosomal and lysosomal deficits that occur in apolipoprotein E4 mouse and human brains. Disruption of these interdependent endosomal-exosomal-lysosomal systems in apolipoprotein E4-expressing individuals may contribute to amyloidogenic amyloid-ß precursor protein processing, compromise trophic signalling and synaptic function, and interfere with a neuron's ability to degrade material, all of which are events that lead to neuronal vulnerability and higher risk of Alzheimer's disease development. Together, these data suggest that exosome pathway dysfunction is a previously unappreciated component of the brain pathologies that occur as a result of apolipoprotein E4 expression.
Assuntos
Apolipoproteína E4/biossíntese , Encéfalo/metabolismo , Exossomos/metabolismo , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/metabolismo , Alelos , Animais , Apolipoproteína E3/genética , Apolipoproteína E4/genética , Proteínas de Ligação a DNA/biossíntese , Regulação para Baixo , Complexos Endossomais de Distribuição Requeridos para Transporte/biossíntese , Exossomos/ultraestrutura , Espaço Extracelular/metabolismo , Feminino , Genótipo , Humanos , Metabolismo dos Lipídeos , Masculino , Camundongos , Camundongos Transgênicos , Pessoa de Meia-Idade , Fatores de Transcrição/biossíntese , Proteínas rab de Ligação ao GTP/biossínteseRESUMO
BACKGROUND: This study aimed to examine the level of perception of the technical terms related to the effect of radiation on the human body among residents of the six prefectures of Miyagi, Fukushima, Tokyo, Aichi, Hiroshima, and Nagasaki in Japan. Miyagi and Fukushima were selected as devastated area by Great East Japan Earthquake. Tokyo and Aichi were selected as control. Hiroshima and Nagasaki were selected as the A-bombed area. METHODS: A total of 1030 respondents, 172, 173, 171, 173, 171, and 170, respectively, were surveyed. Differences in the recognition level of technical terms related to the effect of radiation on the human body among residents of the six prefectures were assessed. RESULTS: The highest recognition levels were reported by the respondents from Fukushima (17 items). Those from Miyagi scored the second highest recognition levels (10 out of the 17 terms); the second highest recognition levels for the remaining seven terms were marked by the respondents of Tokyo. Respondents in the Tohoku region had a better recognition for the technical terminology relevant to the effect of radiation on the human body. CONCLUSIONS: Our findings indicate a need for continued, comprehensive risk communication pertaining to health hazards of radiation exposure in Tohoku region. Concerted efforts by central/local governments and other stakeholders are required to allay the anxiety/stress related to radiation exposure among the residents.
Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Efeitos da Radiação , Exposição à Radiação , Humanos , Japão , Exposição à Radiação/efeitos adversos , Terminologia como AssuntoRESUMO
2-hydroxypropyl-ß-cyclodextrin (CYCLO), a modifier of cholesterol efflux from cellular membrane and endo-lysosomal compartments, reduces lysosomal lipid accumulations and has therapeutic effects in animal models of Niemann-Pick disease type C and several other neurodegenerative states. Here, we investigated CYCLO effects on autophagy in wild-type mice and TgCRND8 mice-an Alzheimer's Disease (AD) model exhibiting ß-amyloidosis, neuronal autophagy deficits leading to protein and lipid accumulation within greatly enlarged autolysosomes. A 14-day intracerebroventricular administration of CYCLO to 8-month-old TgCRND8 mice that exhibit moderately advanced neuropathology markedly diminished the sizes of enlarged autolysosomes and lowered their content of GM2 ganglioside and Aß-immunoreactivity without detectably altering amyloid precursor protein processing or extracellular Aß/ß-amyloid burden. We identified two major actions of CYCLO on autophagy underlying amelioration of lysosomal pathology. First, CYCLO stimulated lysosomal proteolytic activity by increasing cathepsin D activity, levels of cathepsins B and D and two proteins known to interact with cathepsin D, NPC1 and ABCA1. Second, CYCLO impeded autophagosome-lysosome fusion as evidenced by the accumulation of LC3, SQSTM1/p62, and ubiquitinated substrates in an expanded population of autophagosomes in the absence of greater autophagy induction. By slowing substrate delivery to lysosomes, autophagosome maturational delay, as further confirmed by our in vitro studies, may relieve lysosomal stress due to accumulated substrates. These findings provide in vivo evidence for lysosomal enhancing properties of CYCLO, but caution that prolonged interference with cellular membrane fusion/autophagosome maturation could have unfavorable consequences, which might require careful optimization of dosage and dosing schedules.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Amiloidose/tratamento farmacológico , Ciclodextrinas/administração & dosagem , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides , Amiloidose/metabolismo , Animais , Autofagia/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Lisossomos/metabolismo , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologiaRESUMO
Extracellular vesicles (EV), including exosomes, secreted vesicles of endocytic origin, and microvesicles derived from the plasma membrane, have been widely isolated and characterized from conditioned culture media and bodily fluids. The difficulty in isolating EV from tissues, however, has hindered their study in vivo. Here, we describe a novel method designed to isolate EV and characterize exosomes from the extracellular space of brain tissues. The purification of EV is achieved by gentle dissociation of the tissue to free the brain extracellular space, followed by sequential low-speed centrifugations, filtration, and ultracentrifugations. To further purify EV from other extracellular components, they are separated on a sucrose step gradient. Characterization of the sucrose step gradient fractions by electron microscopy demonstrates that this method yields pure EV preparations free of large vesicles, subcellular organelles, or debris. The level of EV secretion and content are determined by assays for acetylcholinesterase activity and total protein estimation, and exosomal identification and protein content are analyzed by Western blot and immuno-electron microscopy. Additionally, we present here a method to delipidate EV in order to improve the resolution of downstream electrophoretic analysis of EV proteins.
Assuntos
Encéfalo/metabolismo , Fracionamento Celular/métodos , Exossomos/metabolismo , Vesículas Extracelulares/metabolismo , Animais , Biomarcadores , Centrifugação com Gradiente de Concentração , Meios de Cultivo Condicionados , Exossomos/química , Exossomos/ultraestrutura , Espaço Extracelular , Vesículas Extracelulares/química , Vesículas Extracelulares/ultraestrutura , Camundongos , Microscopia Eletrônica , UltracentrifugaçãoRESUMO
Ethanol induces neurodegeneration in the developing brain, which may partially explain the long-lasting adverse effects of prenatal ethanol exposure in fetal alcohol spectrum disorders (FASD). While animal models of FASD show that ethanol-induced neurodegeneration is associated with glial activation, the relationship between glial activation and neurodegeneration has not been clarified. This review focuses on the roles of activated microglia and astrocytes in neurodegeneration triggered by ethanol in rodents during the early postnatal period (equivalent to the third trimester of human pregnancy). Previous literature indicates that acute binge-like ethanol exposure in postnatal day 7 (P7) mice induces apoptotic neurodegeneration, transient activation of microglia resulting in phagocytosis of degenerating neurons, and a prolonged increase in glial fibrillary acidic protein-positive astrocytes. In our present study, systemic administration of a moderate dose of lipopolysaccharides, which causes glial activation, attenuates ethanol-induced neurodegeneration. These studies suggest that activation of microglia and astrocytes by acute ethanol in the neonatal brain may provide neuroprotection. However, repeated or chronic ethanol can induce significant proinflammatory glial reaction and neurotoxicity. Further studies are necessary to elucidate whether acute or sustained glial activation caused by ethanol exposure in the developing brain can affect long-lasting cellular and behavioral abnormalities observed in the adult brain.
RESUMO
A 60-year-old man was diagnosed with adenocarcinoma of the esophagogastric junction with lymph node metastasis along the left gastric artery. The clinical stage was determined to be T4b, N1, M0, Stage IIIB, and a neoadjuvant chemotherapy (NAC)regimen of capecitabine/CDDP plus trastuzumab was selected for treatment. Before 3 courses of chemotherapy, the patient developed perforated gastric cancer. With conservative therapy, we were able to obtain closure of the perforation without affecting the curability of the cancer. We changed the chemotherapy regimen to S-1/CDDP plus trastuzumab, and the patient underwent curative resection.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Junção Esofagogástrica/patologia , Terapia Neoadjuvante , Gastropatias/cirurgia , Neoplasias Gástricas/tratamento farmacológico , Cisplatino/administração & dosagem , Combinação de Medicamentos , Humanos , Masculino , Ácido Oxônico/administração & dosagem , Receptor ErbB-2/análise , Gastropatias/etiologia , Neoplasias Gástricas/complicações , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgia , Tegafur/administração & dosagem , Trastuzumab/administração & dosagem , Resultado do TratamentoRESUMO
According to the "Japan Revitalization Strategy" established in June 2013, "the government will promote better contributions of local pharmacies and pharmacists in encouraging self-medication of citizens by making pharmacies the community-based hub for providing information, giving advice on the proper use of non-prescription drugs, etc. and offering consultation and information service concerning health". In addition, the "Demanded Function and Ideal Form of Pharmacy," published in January 2014, requested a change, from pharmacies that specialized in dispensing medicines to pharmacies that serve as whole healthcare stations, providing pharmaceutical care based on patients' medical history, including the intake of dietary supplements. The medication fee was revised in April 2014 to enhance family pharmacy services and the management of pharmaceutical care. At that time, blood testing at a registered pharmacy was officially allowed under strict regulation. Revision of the "Pharmacist Law" in June 2014 included a request to pharmacists to provide pharmaceutical advice in addition to information. For the mitigation of drug-induced tragedies, the "Pharmaceutical Affairs Law" was amended to the "Pharmaceutical and Medical Device Act (PMD Act)" in November 2014, and proper use of medicines was imposed on healthcare professionals and other stakeholders. Patients were also requested to learn and understand the safety and harmful effects of medicines, and were requested to use medicines appropriately. As mentioned above, the status of pharmacies and pharmacists has dramatically changed in the past 2 years, and such changes over time are required.
Assuntos
Serviços Comunitários de Farmácia/tendências , Serviços de Informação sobre Medicamentos , Equipamentos e Provisões , Farmácias , Papel Profissional , Serviços Comunitários de Farmácia/legislação & jurisprudência , Humanos , Farmacêuticos/legislação & jurisprudênciaRESUMO
The purpose of this study was to propose a method for visualizing the patterns of the geographical propagation of influenza infection, and to elaborate parameters for the characterization of these patterns. First, a motion picture was prepared for the quotidian propagation of influenza infection in the Greater Tokyo Metropolitan area, which is considered a typical epidemic area for the 2012/2013 flu season. Second, hebdomadal recordings of patients with influenza infection in the 47 prefectures of Japan were grouped into 3 categories (1-peak, 2-peak, or multi-peak). The prefectures were arranged according to the weeks with the maximum number of patients, to examine variations in the temporal infection order of the districts among the flu seasons. These characteristics were analyzed using Cramer's coefficient of association and Spearman's rank correlation coefficient. Finally, the propagation of influenza infection was compared between urban and remote areas: the Greater Tokyo Metropolitan area and Tochigi prefecture. Regarding influenza virus infection, differences in population density, public transportation systems, and lifestyles between the urban and rural areas were found to lead to distinct endemic patterns of infection. Emphasis was placed on the so-called big data hubris.
Assuntos
Bases de Dados Factuais , Nível de Saúde , Influenza Humana/epidemiologia , Influenza Humana/transmissão , Farmácias , Geografia , Humanos , Influenza Humana/prevenção & controle , Japão/epidemiologia , Densidade Demográfica , Meios de Transporte , População UrbanaRESUMO
Kampo medicines must be used according to an individual's physical characteristics and symptoms to avoid lack of efficacy, adverse reactions or interactions with other drugs. As category-2 over-the-counter drugs (OTCs), Kampo OTCs are not targets of active explanations by pharmacists, and consumers usually decide to use OTCs by themselves on the basis of drug label information. However, information on the label is occasionally brief. To promote the proper use of Kampo OTCs, we herein propose an informative tool based on the Australian Shelf-Talker (information on the proper use of OTCs with a self-check questionnaire for consumers), the Self-Check Card (SCC). We also prepared the informative material, Information to the Pharmacist (IP), directed at pharmacists regarding these Kampo OTCs. We created SCCs and IPs for 16 prescriptions in the 5 most demanded categories (cold, cough/sore throat, urination problems, women's diseases, and shoulder stiffness or joint/nerve pain). The SCC with questions in a simplified language specifies individuals who should avoid the drug, or those who should consult a pharmacist before purchase, according to the safety information on the respective drug labels. The IP provides information to pharmacists on safety issues and those concerning recognition of the consumer's symptoms and physical characteristics needed for the selection of appropriate Kampo OTCs. Such SCCs and IPs are now in use in 2 pharmacies to know pharmacists' suggestions about improvements and consumer's opinions and degree of satisfaction. We believe these risk-benefit communication tools, SCC and IP, will contribute to improve the proper use of Kampo OTCs.
Assuntos
Serviços Comunitários de Farmácia , Qualidade de Produtos para o Consumidor , Serviços de Informação sobre Medicamentos , Medicamentos de Ervas Chinesas , Medicina Kampo , Medicamentos sem Prescrição , Farmacêuticos , Rotulagem de Medicamentos , HumanosRESUMO
Our previous studies have shown accumulation of GM2 ganglioside during ethanol-induced neurodegeneration in the developing brain, and GM2 elevation has also been reported in other brain injuries and neurodegenerative diseases. Using GM2/GD2 synthase KO mice lacking GM2/GD2 and downstream gangliosides, the current study explored the significance of GM2 elevation in WT mice. Immunohistochemical studies indicated that ethanol-induced acute neurodegeneration in postnatal day 7 (P7) WT mice was associated with GM2 accumulation in the late endosomes/lysosomes of both phagocytic microglia and increased glial fibrillary acidic protein (GFAP)-positive astrocytes. However, in KO mice, although ethanol induced robust neurodegeneration and accumulation of GD3 and GM3 in the late endosomes/lysosomes of phagocytic microglia, it did not increase the number of GFAP-positive astrocytes, and the accumulation of GD3/GM3 in astrocytes was minimal. Not only ethanol, but also DMSO, induced GM2 elevation in activated microglia and astrocytes along with neurodegeneration in P7 WT mice, while lipopolysaccharide, which did not induce significant neurodegeneration, caused GM2 accumulation mainly in lysosomes of activated astrocytes. Thus, GM2 elevation is associated with activation of microglia and astrocytes in the injured developing brain, and GM2, GD2, or other downstream gangliosides may regulate astroglial responses in ethanol-induced neurodegeneration.
Assuntos
Encéfalo/citologia , Encéfalo/crescimento & desenvolvimento , Gangliosídeos/metabolismo , Técnicas de Inativação de Genes , N-Acetilgalactosaminiltransferases/deficiência , N-Acetilgalactosaminiltransferases/genética , Neuroglia/citologia , Animais , Astrócitos/citologia , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Dimetil Sulfóxido/farmacologia , Endossomos/efeitos dos fármacos , Endossomos/metabolismo , Etanol/farmacologia , Proteína Glial Fibrilar Ácida , Lipopolissacarídeos/farmacologia , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Microglia/citologia , Microglia/efeitos dos fármacos , Microglia/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neuroglia/efeitos dos fármacos , Neuroglia/metabolismo , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Polipeptídeo N-AcetilgalactosaminiltransferaseRESUMO
Autophagy, the major lysosomal pathway for the turnover of intracellular organelles is markedly impaired in neurons in Alzheimer's disease and Alzheimer mouse models. We have previously reported that severe lysosomal and amyloid neuropathology and associated cognitive deficits in the TgCRND8 Alzheimer mouse model can be ameliorated by restoring lysosomal proteolytic capacity and autophagy flux via genetic deletion of the lysosomal protease inhibitor, cystatin B. Here we present evidence that macroautophagy is a significant pathway for lipid turnover, which is defective in TgCRND8 brain where lipids accumulate as membranous structures and lipid droplets within giant neuronal autolysosomes. Levels of multiple lipid species including several sphingolipids (ceramide, ganglioside GM3, GM2, GM1, GD3 and GD1a), cardiolipin, cholesterol and cholesteryl esters are elevated in autophagic vacuole fractions and lysosomes isolated from TgCRND8 brain. Lipids are localized in autophagosomes and autolysosomes by double immunofluorescence analyses in wild-type mice and colocalization is increased in TgCRND8 mice where abnormally abundant GM2 ganglioside-positive granules are detected in neuronal lysosomes. Cystatin B deletion in TgCRND8 significantly reduces the number of GM2-positive granules and lowers the levels of GM2 and GM3 in lysosomes, decreases lipofuscin-related autofluorescence, and eliminates giant lipid-containing autolysosomes while increasing numbers of normal-sized autolysosomes/lysosomes with reduced content of undigested components. These findings have identified macroautophagy as a previously unappreciated route for delivering membrane lipids to lysosomes for turnover, a function that has so far been considered to be mediated exclusively through the endocytic pathway, and revealed that autophagic-lysosomal dysfunction in TgCRND8 brain impedes lysosomal turnover of lipids as well as proteins. The amelioration of lipid accumulation in TgCRND8 by removing cystatin B inhibition on lysosomal proteases suggests that enhancing lysosomal proteolysis improves the overall environment of the lysosome and its clearance functions, which may be possibly relevant to a broader range of lysosomal disorders beyond Alzheimer's disease.