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1.
Int J Mol Sci ; 22(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34360989

RESUMO

Increasing evidence suggests that elderly people with dementia are vulnerable to the development of severe coronavirus disease 2019 (COVID-19). In Alzheimer's disease (AD), the major form of dementia, ß-amyloid (Aß) levels in the blood are increased; however, the impact of elevated Aß levels on the progression of COVID-19 remains largely unknown. Here, our findings demonstrate that Aß1-42, but not Aß1-40, bound to various viral proteins with a preferentially high affinity for the spike protein S1 subunit (S1) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the viral receptor, angiotensin-converting enzyme 2 (ACE2). These bindings were mainly through the C-terminal residues of Aß1-42. Furthermore, Aß1-42 strengthened the binding of the S1 of SARS-CoV-2 to ACE2 and increased the viral entry and production of IL-6 in a SARS-CoV-2 pseudovirus infection model. Intriguingly, data from a surrogate mouse model with intravenous inoculation of Aß1-42 show that the clearance of Aß1-42 in the blood was dampened in the presence of the extracellular domain of the spike protein trimers of SARS-CoV-2, whose effects can be prevented by a novel anti-Aß antibody. In conclusion, these findings suggest that the binding of Aß1-42 to the S1 of SARS-CoV-2 and ACE2 may have a negative impact on the course and severity of SARS-CoV-2 infection. Further investigations are warranted to elucidate the underlying mechanisms and examine whether reducing the level of Aß1-42 in the blood is beneficial to the fight against COVID-19 and AD.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Enzima de Conversão de Angiotensina 2/metabolismo , Fragmentos de Peptídeos/metabolismo , SARS-CoV-2/enzimologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Células A549 , Doença de Alzheimer/complicações , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/química , Animais , COVID-19/complicações , COVID-19/metabolismo , Chlorocebus aethiops , Humanos , Interleucina-6/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fragmentos de Peptídeos/química , Subunidades Proteicas/química , Subunidades Proteicas/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Células Vero , Internalização do Vírus
2.
Behav Neurol ; 2021: 6301458, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34336001

RESUMO

Prenatal exposure to buprenorphine renders offspring vulnerable to cerebral impairments. In this study, our data demonstrate, for the first time, that prenatal exposure to buprenorphine escalates astrocyte activation concurrent with indications of endoplasmic reticulum (ER) stress in the hippocampi of neonates, and this can be prevented by the coadministration of dextromethorphan with buprenorphine. Furthermore, dextromethorphan can inhibit the accumulation of GPR37 in the hippocampus of newborns caused by buprenorphine and is accompanied by the proapoptotic ER stress response that involves the procaspase-3/CHOP pathway. Primary astrocyte cultures derived from the neonates of the buprenorphine group also displayed aberrant ER calcium mobilization and elevated basal levels of cyclooxygenase-2 (COX-2) at 14 days in vitro while showing sensitivity to lipopolysaccharide-activated expression of COX-2. Similarly, these long-lasting defects in the hippocampus and astrocytes were abolished by dextromethorphan. Our findings suggest that prenatal exposure to buprenorphine might instigate long-lasting effects on hippocampal and astrocytic functions. The beneficial effects of prenatal coadministration of dextromethorphan might be, at least in part, attributed to its properties in attenuating astrocyte activation and hippocampal ER stress in neonates.


Assuntos
Buprenorfina , Efeitos Tardios da Exposição Pré-Natal , Apoptose , Astrócitos , Dextrometorfano/toxicidade , Estresse do Retículo Endoplasmático , Feminino , Humanos , Recém-Nascido , Gravidez , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente
3.
Neurobiol Aging ; 90: 60-74, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31879131

RESUMO

High-fat and high-sugar diets contribute to the prevalence of type 2 diabetes and Alzheimer's disease (AD). Although the impact of high-fat diets on AD pathogenesis has been established, the effect of high-sucrose diets (HSDs) on AD pathogenesis remains unclear. This study sought to determine the impact of HSDs on AD-related pathologies. Male APPswe/PS1dE9 (APP/PS1) transgenic and wild-type mice were provided with HSD and their cognitive and hypothalamus-related noncognitive parameters, including feeding behaviors and glycemic regulation, were compared. HSD-fed APP/PS1 mice showed increased neuroinflammation, as well as increased cortical and serum levels of amyloid-ß. HSD-fed APP/PS1 mice showed aggravated obesity, hyperinsulinemia, insulin resistance, and leptin resistance, but there was no induction of hyperphagia or hyperleptinemia. Leptin-induced phosphorylation of signal transducer and activator of transcription 3 in the dorsomedial and ventromedial hypothalamus was reduced in HSD-fed APP/PS1 mice, which might be associated with attenuated food-anticipatory activity, glycemic dysregulation, and AD-related noncognitive symptoms. Our study demonstrates that HSD aggravates metabolic stresses, increases AD-related pathologies, and attenuates hypothalamic leptin signaling in APP/PS1 mice.


Assuntos
Doença de Alzheimer/etiologia , Doença de Alzheimer/metabolismo , Antecipação Psicológica/efeitos dos fármacos , Dieta da Carga de Carboidratos/efeitos adversos , Ingestão de Alimentos/psicologia , Hipotálamo/metabolismo , Leptina/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sacarose/efeitos adversos , Doença de Alzheimer/patologia , Doença de Alzheimer/psicologia , Peptídeos beta-Amiloides/metabolismo , Animais , Inflamação , Camundongos Transgênicos , Fator de Transcrição STAT3/metabolismo
4.
Mol Neurobiol ; 56(12): 8451-8474, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31257558

RESUMO

Astrocytes play pivotal roles in regulating glutamate homeostasis at tripartite synapses. Inhibition of soluble epoxide hydrolase (sEHi) provides neuroprotection by blocking the degradation of 14,15-epoxyeicosatrienoic acid (14,15-EET), a lipid mediator whose synthesis can be activated downstream from group 1 metabotropic glutamate receptor (mGluR) signaling in astrocytes. However, it is unclear how sEHi regulates glutamate excitotoxicity. Here, we used three primary rat cortical culture systems, neuron-enriched (NE), astrocyte-enriched glia-neuron mix (GN), and purified astrocytes, to delineate the underlying mechanism by which sEHi and 14,15-EET attenuate excitotoxicity. We found that sEH inhibitor 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA) and 14,15-EET both attenuated N-methyl-D-aspartate (NMDA)-induced neurite damage and cell death in GN, not NE, cortical cultures. The anti-excitotoxic effects of 14,15-EET and AUDA were both blocked by the group 1 mGluR5 antagonist 2-methyl-6-(phenylethynyl)pyridine (MPEP), as were their protective effects against NMDA-disrupted perineuronal astrocyte processes expressing glutamate transporter-1 (GLT-1) and subsequent glutamate uptake. Knockdown of sEH expression also attenuated NMDA neurotoxicity in mGluR5- and GLT-1-dependent manners. The 14,15-EET/AUDA-preserved astroglial integrity was confirmed in glutamate-stimulated primary astrocytes along with the reduction of the c-Jun N-terminal kinase 1 phosphorylation, in which the 14,15-EET effect is mGluR5-dependent. In vivo studies validated that sEHi and genetic deletion of sEH (Ephx2-KO) ameliorated excitotoxic kainic acid-induced seizure, memory impairment, and neuronal loss while preserving GLT-1-expressing perineuronal astrocytes in hippocampal CA3 subregions. These results suggest that 14,15-EET mediates mGluR5-dependent anti-excitotoxicity by protecting astrocytes to maintain glutamate homeostasis, which may account for the beneficial effect of sEH inhibition in excitotoxic brain injury and diseases.


Assuntos
Ácido 8,11,14-Eicosatrienoico/análogos & derivados , Astrócitos/patologia , Inibidores Enzimáticos/farmacologia , Epóxido Hidrolases/antagonistas & inibidores , Ácido Glutâmico/metabolismo , Homeostase , Plasticidade Neuronal/efeitos dos fármacos , Neurotoxinas/toxicidade , Ácido 8,11,14-Eicosatrienoico/farmacologia , Adamantano/análogos & derivados , Adamantano/farmacologia , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Epóxido Hidrolases/metabolismo , Transportador 2 de Aminoácido Excitatório/metabolismo , Hipocampo/metabolismo , Ácido Caínico , Ácidos Láuricos/farmacologia , Camundongos Endogâmicos C57BL , Proteína Quinase 8 Ativada por Mitógeno/metabolismo , Modelos Biológicos , N-Metilaspartato , Neuroglia/efeitos dos fármacos , Neuroglia/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Ratos Sprague-Dawley , Receptor de Glutamato Metabotrópico 5/antagonistas & inibidores , Receptor de Glutamato Metabotrópico 5/metabolismo , Solubilidade
5.
Mol Neurobiol ; 56(12): 8475-8476, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31317492

RESUMO

The original version of this article unfortunately contained a mistake. The authors observed inadvertent error in Fig. 7d, in which the image of the GFAP/DAPI in the WT saline treated mice was rotated left 90-degree by mistake. The corrected representative image is given below.

6.
J Neuroinflammation ; 16(1): 123, 2019 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-31176371

RESUMO

BACKGROUND: Astrocyte activation is a common pathological feature in many brain diseases with neuroinflammation, and revealing the underlying mechanisms might shed light on the regulatory processes of the diseases. Recently, soluble epoxide hydrolase (sEH) has been proposed to affect neuroinflammation in brain injuries. However, the roles of astrocytic sEH in brains with neurodegeneration remain unclear. METHODS: The expression of astrocytic sEH in the brains of APPswe/PSEN1dE9 (APP/PS1) mice developing Alzheimer's disease (AD)-like pathology was evaluated by confocal imaging. LPS-activated primary astrocytes with mRNA silencing or overexpression of sEH were used to investigate its regulatory roles in astrocyte activation and the induction of pro-inflammatory markers. Primary astrocytes isolated from a sEH knockout (sEH-/-) background were also applied. RESULTS: The immunoreactivity of sEH was increased in activated astrocytes in parallel with the progression of AD in APP/PS1 mice. Our data from primary astrocyte cultures further demonstrate that the overexpression of sEH ameliorated, while the silencing of sEH mRNA enhanced, the lipopolysaccharides (LPS)-induced expression of pro-inflammatory markers, such as inducible nitric oxide, cyclooxygenase 2 (COX-2), and pro-inflammatory cytokines. These findings suggest that sEH negatively regulates astrocyte immune responses. Enhanced immune responses found in LPS-activated sEH-/- astrocytes also support the notion that the expression of sEH could suppress the immune responses during astrocyte activation. Similarly, sEH-/- mice that received intraperitoneal injection of LPS showed exacerbated astrocyte activation in the brain, as observed by the elevated expression of glial fibrillary acidic protein (GFAP) and pro-inflammatory markers. Moreover, our data show that the phosphorylation of the signal transducer and activator of transcription 3 (STAT3) was upregulated in activated astrocytes from sEH mouse brains, and the pharmacological blockade of STAT3 activity alleviated the pro-inflammatory effects of sEH deletion in LPS-activated primary astrocytes. CONCLUSIONS: Our results provide evidence, for the first time, showing that sEH negatively regulates astrocytic immune responses and GFAP expression, while the underlying mechanism at least partly involves the downregulation of STAT3 phosphorylation. The discovery of a novel function for sEH in the negative control of astrocytic immune responses involving STAT3 activation confers further insights into the regulatory machinery of astrocyte activation during the development of neurodegeneration.


Assuntos
Astrócitos/imunologia , Epóxido Hidrolases/imunologia , Fator de Transcrição STAT3/imunologia , Doença de Alzheimer/imunologia , Doença de Alzheimer/metabolismo , Animais , Astrócitos/metabolismo , Epóxido Hidrolases/metabolismo , Humanos , Inflamação/imunologia , Inflamação/metabolismo , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Fator de Transcrição STAT3/metabolismo
7.
Int J Mol Sci ; 19(8)2018 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-30096853

RESUMO

Alzheimer's disease (AD), a progressive neurodegenerative disease is highly associated with metabolic syndromes. We previously demonstrated that glycemic dysregulation and obesity are augmented in high fat diet (HFD)-treated APPswe/PS1dE9 (APP/PS1) transgenic mice. In the current study, the underlying mechanism mediating exacerbated metabolic stresses in HFD APP/PS1 transgenic mice was further examined. APP/PS1 mice developed insulin resistance and, consequently, impaired glucose homeostasis after 10 weeks on HFD. [18F]-2-fluoro-2-deoxy-d-glucose ([18F]-FDG) positron emission tomography showed that interscapular brown adipose tissue is vulnerable to HFD and AD-related pathology. Chronic HFD induced hyperphagia, with limited effects on basal metabolic rates in APP/PS1 transgenic mice. Excessive food intake may be caused by impairment of leptin signaling in the hypothalamus because leptin failed to suppress the food intake of HFD APP/PS1 transgenic mice. Leptin-induced pSTAT3 signaling in the arcuate nucleus was attenuated. Dysregulated energy homeostasis including hyperphagia and exacerbated obesity was elicited prior to the presence of the amyloid pathology in the hypothalamus of HFD APP/PS1 transgenic mice; nevertheless, cortical neuroinflammation and the level of serum Aß and IL-6 were significantly elevated. Our study demonstrates the pivotal role of AD-related pathology in augmenting HFD-induced insulin and leptin resistance and impairing hypothalamic regulation of energy homeostasis.


Assuntos
Doença de Alzheimer/genética , Hiperfagia/tratamento farmacológico , Resistência à Insulina/genética , Obesidade/genética , Tecido Adiposo Marrom/efeitos dos fármacos , Doença de Alzheimer/complicações , Doença de Alzheimer/patologia , Animais , Glicemia , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Ingestão de Alimentos/genética , Homeostase , Humanos , Hiperfagia/genética , Hiperfagia/patologia , Insulina/metabolismo , Insulina/uso terapêutico , Leptina/metabolismo , Leptina/uso terapêutico , Síndrome Metabólica/tratamento farmacológico , Síndrome Metabólica/genética , Síndrome Metabólica/patologia , Camundongos , Camundongos Transgênicos , Obesidade/complicações , Obesidade/patologia
8.
J Ethnopharmacol ; 209: 50-61, 2017 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-28743670

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Metabolic syndrome and vascular dysfunction was suggested to be the risk factors for Alzheimer's disease (AD). Xuefu Zhuyu decoction (XZD) is a traditional Chinese medicine used to treat metabolic syndrome and cardiac-cerebral vascular disease. The effects of XZD on ameliorating metabolic syndrome, amyloid-related pathologies and cognitive impairment in an animal model of AD with metabolic stress was investigated. MATERIALS AND METHOD: The animal model of AD with metabolic stress was created by administrating high-fat diet and a low-dose injection of streptozotocin prior to the appearance of senile plaques in APP/PS1 transgenic mice. The diabesity-associated metabolic changes and AD-related pathological alterations were examined. RESULTS: We found that XZD reduced body weight, insulin and leptin level, HOMA-IR, hepatic triglyceride, serum Aß42 in the metabolic stressed AD animal. XZD also ameliorated oral glucose tolerant, Aß deposition, astrocyte and microglia activation in the vicinity of plaques, and nesting behavior in the metabolic stressed AD animal. CONCLUSION: The results of this study suggest that XZD is able to reduce the peripheral metabolic stress-mediated vascular hypoperfusion, neuroinflammation and AD-related pathology in APP/PS1 mice.


Assuntos
Amiloide/metabolismo , Disfunção Cognitiva/prevenção & controle , Medicamentos de Ervas Chinesas/farmacologia , Fígado Gorduroso/tratamento farmacológico , Inflamação/tratamento farmacológico , Obesidade/tratamento farmacológico , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Glicemia/efeitos dos fármacos , Homeostase , Insulina/sangue , Resistência à Insulina , Leptina/sangue , Masculino , Camundongos , Camundongos Transgênicos , Estresse Fisiológico , Triglicerídeos/metabolismo
9.
J Cell Physiol ; 232(12): 3409-3421, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28075010

RESUMO

In this study, we examine whether an anti-inflammatory thiourea derivative, compound #326, actions on ion channels. The effects of compound #326 on Ca2+ -activated K+ channels were evaluated by patch-clamp recordings obtained in cell-attached, inside-out or whole-cell configuration. In pituitary GH3 cells, compound #326 increased the amplitude of Ca2+ -activated K+ currents (IK(Ca) ) with an EC50 value of 11.6 µM, which was reversed by verruculogen, but not tolbutamide or TRAM-34. Under inside-out configuration, a bath application of compound #326 raised the probability of large-conductance Ca2+ -activated K+ (BKCa ) channels. The activation curve of BKCa channels was shifted to less depolarised potential with no modification of the gating charge of the curve; consequently, the difference of free energy was reduced in the presence of this compound. Compound #326-stimulated activity of BKCa channels is explained by a shortening of mean closed time, despite its inability to alter single-channel conductance. Neither delayed-rectifier nor erg-mediated K+ currents was modified. Compound #326 decreased the peak amplitude of voltage-gated Na+ current with no clear change in the overall current-voltage relationship of this current. In HEK293T cells expressing α-hSlo, compound #326 enhanced BKCa channels effectively. Intriguingly, the inhibitory actions of compound #326 on interleukin 1ß in lipopolysaccharide-activated microglia were significantly reversed by verruculogen, whereas BKCa channel inhibitors suppressed the expressions of inducible nitric oxide synthase. The BKCa channels could be an important target for compound #326 if similar in vivo results occur, and the multi-functionality of BKCa channels in modulating microglial immunity merit further investigation.


Assuntos
Anti-Inflamatórios/farmacologia , Agonistas dos Canais de Cálcio/farmacologia , Sinalização do Cálcio/efeitos dos fármacos , Cálcio/metabolismo , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/agonistas , Tioureia/farmacologia , Animais , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Células HEK293 , Humanos , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Ativação do Canal Iônico/efeitos dos fármacos , Cinética , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/genética , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/metabolismo , Lipopolissacarídeos/farmacologia , Potenciais da Membrana , Camundongos Endogâmicos BALB C , Microglia/efeitos dos fármacos , Microglia/metabolismo , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Neoplasias Hipofisárias/metabolismo , Ratos , Tioureia/análogos & derivados , Transfecção
10.
J Neurosci ; 36(6): 2027-43, 2016 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-26865625

RESUMO

UNLABELLED: Growth-associated protein 43 (GAP43), a protein kinase C (PKC)-activated phosphoprotein, is often implicated in axonal plasticity and regeneration. In this study, we found that GAP43 can be induced by the endotoxin lipopolysaccharide (LPS) in rat brain astrocytes both in vivo and in vitro. The LPS-induced astrocytic GAP43 expression was mediated by Toll-like receptor 4 and nuclear factor-κB (NF-κB)- and interleukin-6/signal transducer and activator of transcription 3 (STAT3)-dependent transcriptional activation. The overexpression of the PKC phosphorylation-mimicking GAP43(S41D) (constitutive active GAP43) in astrocytes mimicked LPS-induced process arborization and elongation, while application of a NF-κB inhibitory peptide TAT-NBD or GAP43(S41A) (dominant-negative GAP43) or knockdown of GAP43 all inhibited astrogliosis responses. Moreover, GAP43 knockdown aggravated astrogliosis-induced microglial activation and expression of proinflammatory cytokines. We also show that astrogliosis-conditioned medium from GAP43 knock-down astrocytes inhibited GAP43 phosphorylation and axonal growth, and increased neuronal damage in cultured rat cortical neurons. These proneurotoxic effects of astrocytic GAP43 knockdown were accompanied by attenuated glutamate uptake and expression of the glutamate transporter excitatory amino acid transporter 2 (EAAT2) in LPS-treated astrocytes. The regulation of EAAT2 expression involves actin polymerization-dependent activation of the transcriptional coactivator megakaryoblastic leukemia 1 (MKL1), which targets the serum response elements in the promoter of rat Slc1a2 gene encoding EAAT2. In sum, the present study suggests that astrocytic GAP43 mediates glial plasticity during astrogliosis, and provides beneficial effects for neuronal plasticity and survival and attenuation of microglial activation. SIGNIFICANCE STATEMENT: Astrogliosis is a complex state in which injury-stimulated astrocytes exert both protective and harmful effects on neuronal survival and plasticity. In this study, we demonstrated for the first time that growth-associated protein 43 (GAP43), a well known growth cone protein that promotes axonal regeneration, can be induced in rat brain astrocytes by the proinflammatory endotoxin lipopolysaccharide via both nuclear factor-κB and signal transducer and activator of transcription 3-mediated transcriptional activation. Importantly, LPS-induced GAP43 mediates plastic changes of astrocytes while attenuating astrogliosis-induced microglial activation and neurotoxicity. Hence, astrocytic GAP43 upregulation may serve to indicate beneficial astrogliosis after CNS injury.


Assuntos
Astrócitos/efeitos dos fármacos , Proteína GAP-43/biossíntese , Proteína GAP-43/genética , Gliose/genética , Microglia/efeitos dos fármacos , NF-kappa B/genética , Síndromes Neurotóxicas/genética , Síndromes Neurotóxicas/patologia , Fator de Transcrição STAT3/genética , Receptor 4 Toll-Like/genética , Animais , Citocinas/biossíntese , Transportador 2 de Aminoácido Excitatório/biossíntese , Transportador 2 de Aminoácido Excitatório/genética , Ativação de Macrófagos/efeitos dos fármacos , Neurônios , Fosforilação , Ratos , Ratos Sprague-Dawley , Transativadores/biossíntese , Transativadores/genética
11.
J Biomed Sci ; 23: 27, 2016 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-26892079

RESUMO

BACKGROUND: The accumulation of soluble oligomeric amyloid-ß peptide (oAß) proceeding the formation of senile plaques contributes to synaptic and memory deficits in Alzheimer's disease. Our previous studies have indentified scavenger receptor A (SR-A), especially SR-A type I (SR-AI), as prominent scavenger receptors on mediating oAß clearance by microglia while glycan moiety and scavenger receptor cysteine-rich (SRCR) domain may play the critical role. Macrophage receptor with collagenous structure (MARCO), another member of class A superfamily with a highly conserved SRCR domain, may also play the similar role on oAß internalization. However, the role of N-glycosylation and SRCR domain of SR-AI and MARCO on oAß internalization remains unclear. RESULT: We found that oAß internalization was diminished in the cells expressing SR-AI harboring mutations of dual N-glycosylation sites (i.e. N120Q-N143Q and N143Q-N184Q) while they were normally surface targeted. Normal oAß internalization was observed in 10 SR-AI-SRCR and 4 MARCO-SRCR surface targeted mutants. Alternatively, the SRCR mutants at ß-sheet and α-helix and on disulfide bone formation obstructed receptor's N-glycosylation and surface targeting. CONCLUSION: Our study reveals that N-glycan moiety is more critical than SRCR domain for SR-A-mediated oAß internalization.


Assuntos
Proteínas de Transporte/metabolismo , Receptores Imunológicos/metabolismo , Substituição de Aminoácidos , Peptídeos beta-Amiloides , Animais , Células COS , Proteínas de Transporte/genética , Chlorocebus aethiops , Glicosilação , Células HEK293 , Humanos , Mutação de Sentido Incorreto , Estrutura Terciária de Proteína , Transporte Proteico/genética , Receptores Imunológicos/genética , Fatores de Processamento de Serina-Arginina
12.
PLoS One ; 10(8): e0134531, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26244977

RESUMO

Diabesity-associated metabolic stresses modulate the development of Alzheimer's disease (AD). For further insights into the underlying mechanisms, we examine whether the genetic background of APPswe/PS1dE9 at the prodromal stage of AD affects peripheral metabolism in the context of diabesity. We characterized APPswe/PS1dE9 transgenic mice treated with a combination of high-fat diet with streptozotocin (HFSTZ) in the early stage of AD. HFSTZ-treated APPswe/PS1dE9 transgenic mice exhibited worse metabolic stresses related to diabesity, while serum ß-amyloid levels were elevated and hepatic steatosis became apparent. Importantly, two-way analysis of variance shows a significant interaction between HFSTZ and genetic background of AD, indicating that APPswe/PS1dE9 transgenic mice are more vulnerable to HFSTZ treatment. In addition, body weight gain, high hepatic triglyceride, and hyperglycemia were positively associated with serum ß-amyloid, as validated by Pearson's correlation analysis. Our data suggests that the interplay between genetic background of AD and HFSTZ-induced metabolic stresses contributes to the development of obesity and hepatic steatosis. Alleviating metabolic stresses including dysglycemia, obesity, and hepatic steatosis could be critical to prevent peripheral ß-amyloid accumulation at the early stage of AD.


Assuntos
Peptídeos beta-Amiloides/sangue , Diabetes Mellitus Experimental/sangue , Fígado Gorduroso/sangue , Obesidade/sangue , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Análise de Variância , Animais , Glicemia/metabolismo , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Modelos Animais de Doenças , Ácidos Graxos não Esterificados/sangue , Humanos , Leptina/sangue , Lipídeos/sangue , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fragmentos de Peptídeos/sangue , Presenilina-1/genética , Presenilina-1/metabolismo , Estresse Fisiológico/genética , Triglicerídeos/metabolismo , Ganho de Peso
13.
Neurobiol Aging ; 36(11): 2984-2994, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26264859

RESUMO

Although metabolic syndrome was suggested to be a risk factor for Alzheimer's disease (AD), the role of metabolic stress in the initiation of AD pathology remains unclear. In this study, metabolic stress was induced by a high-fat diet and low-dose injection of streptozotocin (HFSTZ) before the appearance of senile plaques in APP/PS1 transgenic mice. We found that, HFSTZ treatment exacerbated amyloid beta burden and astrocyte activation in the vicinity of plaques. Moreover, we observed an upregulation of astrocytic S100B expression in the brain parenchyma of HFSTZ-treated APP/PS1 mice concurrent with increased interleukin-6 expression in cerebral microvascular cells. To determine the impact of HFSTZ treatment on brain function, we performed [(18)F]fludeoxyglucose-positron emission tomography and analyzed nesting behavior. HFSTZ treatment impaired nest construction and cerebral glucose metabolism in several brain regions of APP/PS1 mice during the early stage of AD. These results suggest that HFSTZ-induced peripheral metabolic stress may contribute to vascular inflammation and astrocyte reactivity in the parenchyma and may impair activity of daily living skill and cerebral glucose metabolism in APP/PS1 mice.


Assuntos
Astrócitos/metabolismo , Astrócitos/patologia , Encéfalo/metabolismo , Transtornos Cognitivos/etiologia , Glucose/metabolismo , Estresse Fisiológico/fisiologia , Doença de Alzheimer/etiologia , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/irrigação sanguínea , Proteína Glial Fibrilar Ácida/metabolismo , Interleucina-6/metabolismo , Masculino , Síndrome Metabólica/etiologia , Camundongos Transgênicos , Microvasos/metabolismo , Obesidade/etiologia , Placa Amiloide/metabolismo , Placa Amiloide/patologia , Subunidade beta da Proteína Ligante de Cálcio S100/metabolismo , Estreptozocina
14.
Glia ; 63(7): 1138-54, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25690886

RESUMO

The aryl hydrocarbon receptor (AhR) regulates peripheral immunity; but its role in microglia-mediated neuroinflammation in the brain remains unknown. Here, we demonstrate that AhR mediates both anti-inflammatory and proinflammatory effects in lipopolysaccharide (LPS)-activated microglia. Activation of AhR by its ligands, formylindolo[3,2-b]carbazole (FICZ) or 3-methylcholanthrene (3MC), attenuated LPS-induced microglial immune responses. AhR also showed proinflammatory effects, as evidenced by the findings that genetic silence of AhR ameliorated the LPS-induced microglial immune responses and LPS-activated microglia-mediated neurotoxicity. Similarly, LPS-induced expressions of tumor necrosis factor α (TNFα) and inducible nitric oxide synthase (iNOS) were reduced in the cerebral cortex of AhR-deficient mice. Intriguingly, LPS upregulated and activated AhR in the absence of AhR ligands via the MEK1/2 signaling pathway, which effects were associated with a transient inhibition of cytochrome P450 1A1 (CYP1A1). Although AhR ligands synergistically enhance LPS-induced AhR activation, leading to suppression of LPS-induced microglial immune responses, they cannot do so on their own in microglia. Chromatin immunoprecipitation results further revealed that LPS-FICZ co-treatment, but not LPS alone, not only resulted in co-recruitment of both AhR and NFκB onto the κB site of TNFα gene promoter but also reduced LPS-induced AhR binding to the DRE site of iNOS gene promoter. Together, we provide evidence showing that microglial AhR, which can be activated by LPS, exerts bi-directional effects on the regulation of LPS-induced neuroinflammation, depending on the availability of external AhR ligands. These findings confer further insights into the potential link between environmental factors and the inflammatory brain disorders.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Microglia/fisiologia , Receptores de Hidrocarboneto Arílico/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Morte Celular/fisiologia , Linhagem Celular , Células Cultivadas , Córtex Cerebral/imunologia , Cromatina/metabolismo , Citocromo P-450 CYP1A1/metabolismo , Técnicas de Silenciamento de Genes , Lipopolissacarídeos , MAP Quinase Quinase 1/metabolismo , MAP Quinase Quinase 2/metabolismo , Camundongos Endogâmicos BALB C , Camundongos Knockout , Neurônios/fisiologia , Óxido Nítrico Sintase Tipo II/metabolismo , Receptores de Hidrocarboneto Arílico/genética , Transdução de Sinais , Fator de Necrose Tumoral alfa/metabolismo
15.
J Neurosci ; 34(49): 16467-81, 2014 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-25471584

RESUMO

Intrauterine infection (chorioamnionitis) aggravates neonatal hypoxic-ischemic (HI) brain injury, but the mechanisms linking systemic inflammation to the CNS damage remain uncertain. Here we report evidence for brain influx of T-helper 17 (TH17)-like lymphocytes to coordinate neuroinflammatory responses in lipopolysaccharide (LPS)-sensitized HI injury in neonates. We found that both infants with histological chorioamnionitis and rat pups challenged by LPS/HI have elevated expression of the interleukin-23 (IL-23) receptor, a marker of early TH17 lymphocytes, in the peripheral blood mononuclear cells. Post-LPS/HI administration of FTY720 (fingolimod), a sphingosine-1-phosphate receptor agonist that blocks lymphocyte trafficking, mitigated the influx of leukocytes through the choroid plexus and acute induction of nuclear factor-κB signaling in the brain. Subsequently, the FTY720 treatment led to attenuated blood-brain barrier damage, fewer cluster of differentiation 4-positive, IL-17A-positive T-cells in the brain, less proinflammatory cytokine, and better preservation of growth and white matter functions. The FTY720 treatment also provided dose-dependent reduction of brain atrophy, rescuing >90% of LPS/HI-induced brain tissue loss. Interestingly, FTY720 neither opposed pure-HI brain injury nor directly inhibited microglia in both in vivo and in vitro models, highlighting its unique mechanism against inflammation-sensitized HI injury. Together, these results suggest that the dual hit of systemic inflammation and neonatal HI injury triggers early onset of the TH17/IL-17-mediated immunity, which causes severe brain destruction but responds remarkably to the therapeutic blockade of lymphocyte trafficking.


Assuntos
Movimento Celular/efeitos dos fármacos , Hipóxia-Isquemia Encefálica/patologia , Hipóxia-Isquemia Encefálica/prevenção & controle , Inflamação/prevenção & controle , Ativação Linfocitária/efeitos dos fármacos , Linfócitos/efeitos dos fármacos , Propilenoglicóis/farmacologia , Esfingosina/análogos & derivados , Animais , Animais Recém-Nascidos , Atrofia/tratamento farmacológico , Barreira Hematoencefálica/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Corioamnionite/tratamento farmacológico , Corioamnionite/metabolismo , Citocinas/metabolismo , Relação Dose-Resposta a Droga , Feminino , Cloridrato de Fingolimode , Humanos , Hipóxia-Isquemia Encefálica/tratamento farmacológico , Imunossupressores/farmacologia , Imunossupressores/uso terapêutico , Recém-Nascido , Lipopolissacarídeos , Linfócitos/citologia , NF-kappa B/metabolismo , Gravidez , Propilenoglicóis/uso terapêutico , Ratos , Receptores de Interleucina/metabolismo , Esfingosina/farmacologia , Esfingosina/uso terapêutico , Linfócitos T/citologia , Linfócitos T/efeitos dos fármacos , Substância Branca/efeitos dos fármacos
16.
J Biomed Sci ; 20: 54, 2013 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-23915271

RESUMO

BACKGROUND: Insufficient clearance of soluble oligomeric amyloid-ß peptide (oAß) in the central nervous system leads to the synaptic and memory deficits in Alzheimer's disease (AD). Previously we have identified scavenger receptor class A (SR-A) of microglia mediates oligomeric amyloid-ß peptide (oAß) internalization by siRNA approach. SR-A is a member of cysteine-rich domain (SRCR) superfamily which contains proteins actively modulating the innate immunity and host defense, however the functions of the SRCR domain remain unclear. Whether the SRCR domain of SR-AI modulates the receptor surface targeting and ligand internalization was investigated by expressing truncated SR-A variants in COS-7 cells. Surface targeting of SR-A variants was examined by live immunostaining and surface biotinylation assays. Transfected COS-7 cells were incubated with fluorescent oAß and acetylated LDL (AcLDL) to assess their ligand-internalization capabilities. RESULT: Genetic ablation of SR-A attenuated the internalization of oAß and AcLDL by microglia. Half of oAß-containing endocytic vesicles was SR-A positive in both microglia and macrophages. Clathrin and dynamin in SR-AI-mediated oAß internalization were involved. The SRCR domain of SR-AI is encoded by exons 10 and 11. SR-A variants with truncated exon 11 were intracellularly retained, whereas SR-A variants with further truncations into exon 10 were surface-targeted. The fusion of exon 11 to the surface-targeted SR-A variant lacking the SRCR domain resulted in the intracellular retention and the co-immunoprecipitation of Bip chaperon of the endoplasmic reticulum. Surface-targeted variants were N-glycosylated, whereas intracellularly-retained variants retained in high-mannose states. In addition to the collagenous domain, the SRCR domain is a functional binding domain for oAß and AcLDL. Our data suggest that inefficient folding of SR-AI variants with truncated SRCR domain was recognized by the endoplasmic reticulum associated degradation which leads to the immature N- glycosylation and intracellular retention. CONCLUSION: The novel functions of the SRCR domain on regulating the efficacy of receptor trafficking and ligand binding may lead to possible approaches on modulating the innate immunity in Alzheimer's disease and atherosclerosis.


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Estrutura Terciária de Proteína , Receptores Depuradores Classe A/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/genética , Animais , Células COS , Chlorocebus aethiops , Cisteína/genética , Citoplasma/metabolismo , Retículo Endoplasmático/química , Retículo Endoplasmático/genética , Retículo Endoplasmático/metabolismo , Humanos , Lipoproteínas LDL/genética , Lipoproteínas LDL/metabolismo , Dobramento de Proteína , Proteólise , Receptores Depuradores Classe A/química , Receptores Depuradores Classe A/genética , Propriedades de Superfície
17.
J Neurotrauma ; 28(7): 1259-69, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21529317

RESUMO

Curcumin has been proposed for treatment of various neuroinflammatory and neurodegenerative conditions, including post-traumatic inflammation during acute spinal cord injury (SCI). In this study, we examined whether curcumin anti-inflammation involves regulation of astrocyte reactivation, with special focus on the injury-induced RANTES (regulated on expression normal T-cell expressed and secreted) from astrocytes in acute SCI. Male Sprague-Dawley (SD) rats were subjected to impact injury of the spinal cord followed by treatment with curcumin (40 mg/kg i.p.). RANTES and inducible nitric oxide synthase expression as well as RANTES-positive astrocytes were all induced by injury accompanied by the elevation of lipid peroxidation, and attenuated by the curcumin treatment. In primary cultured rat astrocytes challenged with lipopolysaccharide (LPS) to mimic astrocyte reactivation following SCI, LPS induces robust increase of RANTES expression and the effect was also reduced by 1 µM curcumin treatment. Furthermore, cortical neurons cultured with astrocyte conditioned medium (ACM) conditioned with both LPS and curcumin (LPS-curcumin/ACM), which characteristically exhibited decreased RANTES expression when compared with ACM from astrocytes treated with LPS alone (LPS/ACM), showed higher level of cell viability and lower level of cell death as assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction activity assay and lactate dehydrogenase release assay, respectively. Knockdown of RANTES expression by siRNA (siRANTES) shows reduced RANTES expression and release from LPS-reactivated astrocytes, and ACM obtained from this condition (LPS-siRANTES/ACM) becomes less cytotoxic as compared with the LPS-ACM. Therefore, curcumin reduction of robust RANTES production in reactivated astrocytes both in vitro and in vivo may contribute to its neuroprotection and potential application in SCI.


Assuntos
Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Quimiocina CCL5/biossíntese , Quimiocina CCL5/metabolismo , Curcumina/farmacologia , Fármacos Neuroprotetores/farmacologia , Traumatismos da Medula Espinal/tratamento farmacológico , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Anti-Inflamatórios não Esteroides/uso terapêutico , Astrócitos/patologia , Células Cultivadas , Quimiocina CCL5/antagonistas & inibidores , Técnicas de Cocultura , Curcumina/uso terapêutico , Modelos Animais de Doenças , Gliose/tratamento farmacológico , Gliose/etiologia , Gliose/patologia , Lipopolissacarídeos/farmacologia , Masculino , Fármacos Neuroprotetores/uso terapêutico , Ratos , Ratos Sprague-Dawley , Traumatismos da Medula Espinal/metabolismo , Traumatismos da Medula Espinal/patologia
18.
Neurobiol Dis ; 42(3): 221-30, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21220023

RESUMO

The accumulation of soluble oligomeric amyloid-ß peptide (oAß) proceeds the formation of senile plaques and contributes to synaptic and memory deficits in Alzheimer's disease (AD). The mechanism of mediating microglial oAß clearance remains unclear and thought to occur via scavenger receptors (SRs) in microglia. SRs respond to their ligands in a subtype-specific manner. Therefore, we sought to identify the specific subtypes of SRs that mediate oAß internalization and proteases that degrade oAß species in naïve primary microglia. The component of oAß species were characterized by western blot analysis, analytical ultracentrifugation analysis, and atomic force microscopy. The oAß species remained soluble in the medium and microglial lysates during incubation at 37 °C. SR-A, but not CD36, mediated oAß internalization in microglia as suggested by the use of subtype-specific neutralizing antibodies and small interfering RNAs (siRNAs). Immunoprecipitation analysis showed that oAß interacted with SR-A on the plasma membrane. After internalization, over 40% of oAß vesicles were trafficked toward lysosomes and degraded by cysteine proteases, including cathepsin B. The inhibitors of proteasome, neprilysin, matrix metalloproteinases, and insulin degrading enzyme failed to protect internalized oAß from degradation. Our study suggests that SR-A and lysosomal cathepsin B are critical in microglial oAß clearance, providing insight into how microglia are involved in the clearance of oAß and their roles in the early stages of AD.


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Microglia/metabolismo , Receptores Depuradores/metabolismo , Análise de Variância , Animais , Western Blotting , Células Cultivadas , Imuno-Histoquímica , Insulisina/metabolismo , Lisossomos/metabolismo , Camundongos , Neprilisina/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Interferência de RNA , RNA Interferente Pequeno
19.
J Neuroimmune Pharmacol ; 6(1): 28-40, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20820930

RESUMO

Neuroimmune pharmacology is a newly emerging field that intersects with neuroscience, immunology, and pharmacology and that is seeking avenues for translational research and better understanding of disease mechanisms. It focuses on the immunity of the central nervous system (CNS) which is greatly influenced by endogenous effectors, such as cytokines and neurotransmitters, and by exogenous substances, including therapeutic compounds, infectious pathogens, and drugs of abuse. In this article, we attempt to raise awareness of the pivotal discovery of how those mediators affect the immunity of the CNS in both physiological conditions and processes of certain mental illnesses, including psychiatric disorders, neurodegenerative diseases, and cerebral dysfunctions due to drugs of abuse. The abnormality in cytokine networks, neurotransmitter homeostasis, and other immune responses may be involved in the neuropathology associated with those mental illnesses, and the therapeutic effects of the potential treatments can be attributed, at least partially, to their immunomodulatory activities. However, the resulting inflammatory cytokines from certain treatments frequently cause psychiatric complications. In addition, the poor neuropathological outcomes frequently found among drug abusers with HIV-1 infection appear to be related to the neurotoxic and immunomodulatory effects of the drugs used. Importantly, glial cells, especially microglia and astrocytes, are key players in the immunomodulatory activities in the CNS, and the functioning CNS is largely dependent upon the reciprocal interactions between neurons and glial cells. Therefore, glia-neuron interactions have become a critical issue for further understanding the disease mechanism. From this review, readers will gain insights into the new field of neuroimmune pharmacology, with a focus on the impacts of CNS immunity on the mental illnesses.


Assuntos
Encéfalo/imunologia , Citocinas/imunologia , Transtornos Mentais/imunologia , Doenças Neurodegenerativas/imunologia , Neuroimunomodulação/fisiologia , Humanos
20.
Chem Biol Interact ; 188(1): 228-36, 2010 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-20637185

RESUMO

Increasing evidence indicates that microglial activation plays an important role in the pathogenesis of Alzheimer's disease (AD). In AD, activated microglia may facilitate the clearance of beta-amyloid (Abeta), a neurotoxic component in AD pathogenesis. However, microglial activation comes at the cost of triggering neuro-inflammation, which contributes to cerebral dysfunction. Thus, pharmacological approaches that can achieve a favorable combination of a reduced microglia-mediated neuro-inflammation, and an enhanced Abeta clearance may be beneficial for preventing the progression of the disease. Here, we show that some newly synthesized compounds may exert such a combination of functions. Using mouse primary microglia and RAW264.7 cells, we found that some thiourea derivatives significantly enhanced microglial Abeta phagocytosis and suppressed microglial immune responses, as evidenced by the reduced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2). Of note, some commercially available inhibitors for iNOS and/or COX-2, such as ibuprofen, dextromethorphan, and N(G)-methyl-l-arginine (l-NMA), show negligible effects on microglial Abeta phagocytosis. Among the thiourea derivatives, our data show that a lead compound, designated as compound #326, (1-Naphthalen-1-yl-3-[5-(3-thioureido-phenoxy)-pentyl]-thiourea) appears to be the most potent in promoting Abeta phagocytosis and in inhibiting the LPS-induced expression of iNOS and COX-2 (when used at concentrations in the low muM range). The potency of compound #326 may have beneficial effects on modulating microglial activation in AD. The structure-activity relationship indicates that the thiourea group, alkyl linker, and the hydrophobic aryl group largely influence the dual functions of the compounds. These findings may indicate a structural basis for the improved design of future drug therapies for AD.


Assuntos
Microglia/efeitos dos fármacos , Tioureia/farmacologia , Animais , Western Blotting , Linhagem Celular , Ensaio de Imunoadsorção Enzimática , Camundongos , Camundongos Endogâmicos BALB C , Microglia/imunologia
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