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1.
Nat Commun ; 11(1): 319, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31949159

RESUMO

Optimal functioning of neuronal networks is critical to the complex cognitive processes of memory and executive function that deteriorate in Alzheimer's disease (AD). Here we use cellular and animal models as well as human biospecimens to show that AD-related stressors mediate global disturbances in dynamic intra- and inter-neuronal networks through pathologic rewiring of the chaperome system into epichaperomes. These structures provide the backbone upon which proteome-wide connectivity, and in turn, protein networks become disturbed and ultimately dysfunctional. We introduce the term protein connectivity-based dysfunction (PCBD) to define this mechanism. Among most sensitive to PCBD are pathways with key roles in synaptic plasticity. We show at cellular and target organ levels that network connectivity and functional imbalances revert to normal levels upon epichaperome inhibition. In conclusion, we provide proof-of-principle to propose AD is a PCBDopathy, a disease of proteome-wide connectivity defects mediated by maladaptive epichaperomes.

2.
Hortic Res ; 6: 89, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31666958

RESUMO

Prunus mume Sieb. et Zucc., P. armeniaca L., and P. salicina L. are economically important fruit trees in temperate regions. These species are taxonomically perplexing because of shared interspecific morphological traits and variation, which are mainly attributed to hybridization. The chloroplast is cytoplasmically inherited and often used for evolutionary studies. We sequenced the complete chloroplast genomes of P. mume, P. armeniaca, and P. salicina using Illumina sequencing followed by de novo assembly. The three chloroplast genomes exhibit a typical quadripartite structure with conserved genome arrangement, structure, and moderate divergence. The lengths of the genomes are 157,815, 157,797, and 157,916 bp, respectively. The length of the large single-copy region (LSC) region is 86,113, 86,283, and 86,122 bp, and the length of the SSC region is 18,916, 18,734, and 19,028 bp; the IR region is 26,393, 26,390, and 26,383 bp, respectively. Each of the three chloroplast genomes encodes 133 genes, including 94 protein-coding, 31 tRNA, and eight rRNA genes. Differential gene analysis for the three species revealed that trnY-ATA is a unique gene in P. armeniaca; in contrast, the gene trnI-TAT is only present in P. mume and P. salicina, though the position of the gene in these chloroplast genomes differs. Further comparative analysis of the complete chloroplast genome sequences revealed that the ORF genes and the sequences of linked regions rps16 and atpA, atpH and atpI, trnc-GCA and psbD, ycf3 and atpB, and rpL32 and ndhD are significantly different and may be used as molecular markers in taxonomic studies. Phylogenetic evolution analysis of the three species suggests that P. mume has a closer genetic relationship to P. armeniaca than to P. salicina.

3.
Plant Mol Biol ; 101(6): 575-584, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31722090

RESUMO

KEY MESSAGE: We developed a machine learning-based model to identify the hidden labels of m6A candidates from noisy m6A-seq data. Peak-calling approaches, such as MeRIP-seq or m6A-seq, are commonly used to map m6A modifications. However, these technologies can only map m6A sites with 100-200 nt resolution and cannot reveal the precise location or the number of modified residues in a transcript. To address this challenge, we developed a novel machine learning-based approach, named HLMethy, to assign labels to m6A candidates from noisy m6A-seq data. The multiple instance learning framework was adopted and two different training strategies were used to generate the classification model. To test the performance of our model, the m6A sites with single-base resolution were used and our model achieved comparable performance against existing instance-level predictors, which suggest that our model has the potential to improve the data quality of m6A-seq at reduced costs. What's more, our generic framework can be extended to other newly found modifications that are found by peak-calling approaches. The source code of HLMethy is available at https://github.com/liuze-nwafu/HLMethy.


Assuntos
Aprendizado de Máquina , Modelos Teóricos
4.
Medicine (Baltimore) ; 98(40): e17419, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31577756

RESUMO

Prospective cohort studies have been conducted to estimate HIV incidence among men who have sex with men (MSM) in first-line megacities cities (>10 million residents) in China, but few in the second-line large- or middle-size cities. This study was to investigate HIV incidence and cohort retention among MSM in a second-line city Hangzhou in eastern China.A total of 523 HIV-seronegative MSM were recruited during September 2014 to September 2015, and were followed up prospectively at 3, 6, 9, and 12 months. Questionnaire interviews were conducted, and laboratory tests were performed to evaluate baseline syphilis infection and HIV seroconversions. Chi-square test and logistic regression model were used to identify factors associated with cohort retention rate and syphilis prevalence.Of 523 participants, 137 (26.2%) completed 6-month follow-up, and use of Internet for recruiting study participants (vs other recruitments: adjusted odds ratio [AOR] = 0.5; 95% confidence interval [CI]: 0.3-0.8) and being homosexual (vs heterosexual or bisexual: AOR = 0.6; 95% CI: 0.4-0.9) were associated with lower cohort retention. The overall HIV incidence during 12 months of follow-up was 6.6 per 100 person-years (95% CI: 3.4-9.8/100 PY). The prevalence of syphilis at baseline was 6.5% (95% CI: 4.4%-8.6%), and disclosing sexual orientation (AOR = 0.4, 95% CI: 0.2-0.9) was associated with lower risk of syphilis infection.HIV is spreading rapidly among MSM in the second-line Chinese city. Effective interventions are needed to target this population in both first-line megacities and second-line large and middle-size cities.


Assuntos
Infecções por HIV/epidemiologia , Homossexualidade Masculina/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , China , Cidades/epidemiologia , Estudos de Coortes , Infecções por HIV/diagnóstico , Infecções por HIV/psicologia , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Prevalência , Retenção nos Cuidados , Sífilis/epidemiologia , Adulto Jovem
5.
PLoS One ; 14(9): e0222191, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31498816

RESUMO

Potential environmental risks of genetically modified (GM) crops have raised concerns. To better understand the effect of transgenic rice on the bacterial community in paddy soil, a field experiment was carried out using pairs of rice varieties from two subspecies (indica and japonica) containing bar transgene with herbicide resistance and their parental conventional rice. The 16S rRNA gene of soil genomic DNA from different soil layers at the maturity stage was sequenced using high-throughput sequencing on the Illumina MiSeq platform to explore the microbial community diversity among different rice soils. There were no significant differences in diversity indices between transgenic japonica rice and its sister conventional rice (japonica pair) among different soil layers, but, significant differences was observed between transgenic indica rice and its conventional rice (indica pair) in the topsoil layer around concentrated rice roots according to the ace diversity index. Though the japonica rice soil and indica rice soil were shared several key genera, including Rivibacter, Anaeromyxobacter, Roseomonas, Geobacter, Thiobacillus, Clostridium, and Desulfobulbus, the primary bacterial genera in indica rice soil were different from those in japonica rice. Synechococcus and Dechloromonas were present in japonica rice samples, while Chloronema, Flexibacter, and Blastocatella were observed in indica rice soil. Moreover, the abundance of genera between GM and non-GM varieties in japonica rice was significantly different from indica rice, and several bacterial communities influenced these differences. Anaerovorax was more abundant in transgenic japonica rice soil than conventional rice soil, while it was deficient in transgenic indica rice soil compared to conventional rice soil, and opposite responses to Deferrisoma were in that of indica rice. Thus, we concluded that transgenic indica and japonica rice had different effects on soil bacteria compared with their corresponding sister conventional rice. However, these composition and abundance difference only occurred for a few genera but had no effect on the primary genera and soil characteristics were mainly contributed to these differences. Thus, differences in bacterial community structure can be ignored when evaluating the impacts of transgenic rice in the complex soil microenvironment.

6.
ACS Omega ; 4(1): 528-534, 2019 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-31459347

RESUMO

Amorphous photonic structures (APSs) with short-range ordered arrangement have attracted great interest because of their wide view angles. However, the presented methods for the APSs color printing and 3D coating on different substrates and curvatures are lack of control. Here, APSs with angle-independent structural colors were fabricated by the self-assembly of SiO2@Fe3O4 core-shell nanostructures, which were prepared by the hydrolysis of Fe(acac)3 on the silica surfaces. The size of SiO2@Fe3O4 core-shell colloids can be controlled well through the tuning of SiO2 particle size, whereas the coverage of Fe3O4 on silica surfaces can be precisely tailored through altering the mass ratio between Fe3O4 precursor and SiO2. APSs with only short-range ordered structures, uniform noniridescent structural colors, and high color visibility can be obtained through the self-assembly of SiO2@Fe3O4 colloids of different particle sizes in a few minutes. They are mainly attributed to the weak electrostatic repulsion interactions between SiO2@Fe3O4 colloids because of the partial coverage of Fe3O4 on silica surfaces and absorption of the incoherent multiple scattering of visible light from Fe3O4. Moreover, SiO2@Fe3O4 colloids show good adhesion to various substrates, such as paper, glass, plastics, resins, ceramics, and wood, which facilitates the formation of uniform APSs on different substrates. Multicolor prints and 3D coating of APSs on substrates with different curves and roughness can be realized on the basis of the fast assembly of SiO2@Fe3O4 colloids.

7.
Artigo em Inglês | MEDLINE | ID: mdl-31176866

RESUMO

Cysteine oxygenase (CDO) is a mononuclear nonhemoglobin enzyme that catalyzes the production of taurine through the cysteine (Cys) pathway and plays a key role in the biosynthesis of taurine in mammals. However, the function of CDOs in bony fish remains poorly understood. In this study, we cloned CDO genes (CaCDO1 and CaCDO2) from Carassius auratus. The cDNA sequences of both CaCDO1 and CaCDO2 encoded putative proteins with 201 amino acids, which included structural features typical of the CDO protein family. Multiple sequence alignment and phylogenetic analysis showed that CaCDO1 and CaCDO2 shared high sequence identities and similarities with C. carpio homologs. Quantitative real-time polymerase chain reaction (qRT-PCR) results revealed that CaCDO1 and CaCDO2 were both broadly expressed in all selected tissues and developmental stages in C. auratus but had differing mRNA levels. In addition, compared to those of the taurine-free group, the in vivo mRNA expression levels of both CaCDO1 and CaCDO2 significantly decreased with increasing dietary taurine levels from 1.0 to 9.0 g/kg. Furthermore, in vitro taurine treatments showed similar inhibitory effects on the expression of CaCDO1 and CaCDO2 in the intestines of C. auratus. Our results also showed that the mRNA expression of CaCDO2 in the intestines was higher than that of CaCDO1 in response to in vivo and in vitro taurine supplementation. Overall, these data may provide new insights into the regulation of fish CDO expression and provide valuable knowledge for improving dietary formulas in aquaculture.


Assuntos
Cisteína Dioxigenase/genética , Cisteína Dioxigenase/metabolismo , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Carpa Dourada/genética , Carpa Dourada/metabolismo , Taurina/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , DNA Complementar/genética , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Carpa Dourada/crescimento & desenvolvimento , Isoenzimas/genética , Isoenzimas/metabolismo , Filogenia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Taurina/farmacologia , Distribuição Tecidual
8.
Neurosci Lett ; 705: 183-194, 2019 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-31028844

RESUMO

Alzheimer's disease (AD) is characterized by two major pathological lesions in the brain, amyloid plaques and neurofibrillary tangles (NFTs) composed mainly of amyloid-ß (Aß) peptides and hyperphosphorylated tau, respectively. Although accumulation of toxic Aß species in the brain has been proposed as one of the important early events in AD, continued lack of success of clinical trials based on Aß-targeting drugs has triggered the field to seek out alternative disease mechanisms and related therapeutic strategies. One of the new approaches is to uncover novel roles of pathological tau during disease progression. This review will primarily focus on recent advances in understanding the contributions of tau to AD.


Assuntos
Doença de Alzheimer/metabolismo , Doença de Alzheimer/fisiopatologia , Proteínas tau/metabolismo , Proteínas tau/fisiologia , Doença de Alzheimer/complicações , Humanos , Inflamação/complicações , Inflamação/fisiopatologia , Transmissão Sináptica/fisiologia
9.
Fish Shellfish Immunol ; 84: 795-801, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30393177

RESUMO

Mitogen-activated protein kinase kinase 6 (MKK6) is an essential component of the p38MAPK signaling pathway, which is involved in the modulation of inflammation, cell apoptosis and survival responses in mammals. However, the function of MKK6s in teleosts is still unclear. In this study, a fish MKK6 homolog (CiMKK6) was first identified from the grass carp (Ctenopharyngodon idella), a freshwater fish. CiMKK6 cDNA encodes a putative protein of 357 amino acids that contains conserved structural characteristics of the MKK6 family, including the S_TKc domain, SVAKT motif and DVD site. The deduced CiMKK6 protein exhibits high sequence homology with other reported fish MKK6s and shares the closest relationship with MKK6 from Danio rerio. Quantitative real-time PCR (qRT-PCR) analysis revealed that CiMKK6 mRNA was widely expressed in all tested tissues and stages of embryonic development. Additionally, the transcript levels of CiMKK6 in the intestine were significantly upregulated in response to bacterial muramyl dipeptide (MDP) and L-Ala-γ-D-Glu-meso-diaminopimelic acid (Tri-DAP) stimulation. Moreover, subcellular localization analysis indicated that CiMKK6 was distributed in both the cytoplasm and the nucleus of HEK293T cells. Finally, overexpression of CiMKK6 significantly enhanced the transcriptional activity of the AP-1 reporter gene in HEK293T cells. Overall, these findings may help better clarify the immune function of teleost MKK6s and provide new insight into the immune defense mechanisms of grass carp.


Assuntos
Proteínas de Bactérias/imunologia , Carpas/genética , Carpas/imunologia , Imunidade Inata/genética , MAP Quinase Quinase 6/genética , Animais , Proteínas de Bactérias/administração & dosagem , Dipeptídeos/administração & dosagem , Dipeptídeos/imunologia , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Células HEK293 , Humanos , MAP Quinase Quinase 6/metabolismo , Oligopeptídeos/administração & dosagem , Oligopeptídeos/imunologia , Distribuição Aleatória
10.
Nat Biotechnol ; 2018 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-30320766

RESUMO

Full-length RNA sequencing (RNA-Seq) has been applied to bulk tissue, cell lines and sorted cells to characterize transcriptomes, but applying this technology to single cells has proven to be difficult, with less than ten single-cell transcriptomes having been analyzed thus far. Although single splicing events have been described for ≤200 single cells with statistical confidence, full-length mRNA analyses for hundreds of cells have not been reported. Single-cell short-read 3' sequencing enables the identification of cellular subtypes, but full-length mRNA isoforms for these cell types cannot be profiled. We developed a method that starts with bulk tissue and identifies single-cell types and their full-length RNA isoforms without fluorescence-activated cell sorting. Using single-cell isoform RNA-Seq (ScISOr-Seq), we identified RNA isoforms in neurons, astrocytes, microglia, and cell subtypes such as Purkinje and Granule cells, and cell-type-specific combination patterns of distant splice sites. We used ScISOr-Seq to improve genome annotation in mouse Gencode version 10 by determining the cell-type-specific expression of 18,173 known and 16,872 novel isoforms.

11.
Am J Bot ; 105(4): 803-811, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29710426

RESUMO

PREMISE OF THE STUDY: Understanding resource allocation to reproduction, a key factor in life history tradeoffs, has long intrigued plant ecologists. Despite the recognized importance of understanding the movement of resources among flowers following variable pollination, the patterns of resource reallocation to plant reproductive organs have not been thoroughly addressed. In this study, we aimed to empirically explore how resources redistribute within inflorescences in response to differential pollination intensities. METHODS: Using a common herb, Sagittaria trifolia, we conducted supplemental and controlled pollination for single, some, or all flowers in simple and complex inflorescences, and compared their resulting fruiting probabilities, seed production, and average seed masses. KEY RESULTS: Pollen supplementation of a single flower significantly increased its fruiting probability; however, the same manipulation of an inflorescence did not increase its overall reproduction. Single pollen-supplemented flowers had a higher percentage fruit set than inflorescences receiving supplemental pollination. In complex inflorescences, supplemental pollination had no effect on the reproductive success of flowers on the lateral or main branches. CONCLUSIONS: We provided evidence of resource reallocation from controlled to pollen-supplemented flowers in simple inflorescences; however, resources were unlikely to be reallocated between the main and lateral branches in the complex inflorescences, suggesting that flowering branches represent integrated physiological units in S. trifolia. The results also demonstrated that single-flower supplemental pollination would exaggerate pollen limitation and lead to a biased understanding of a plant's reproductive status.


Assuntos
Flores/fisiologia , Polinização/fisiologia , Sagittaria/fisiologia , Flores/metabolismo , Frutas/crescimento & desenvolvimento , Reprodução , Sagittaria/crescimento & desenvolvimento , Sagittaria/metabolismo , Sementes/crescimento & desenvolvimento
12.
Sci Rep ; 7(1): 14125, 2017 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-29074878

RESUMO

Alzheimer's disease (AD) is a degenerative brain disease that destroys memory and other important mental functions but lacks efficient therapeutic agents. Blocking toxic amyloid ß (Aß) could be beneficial for AD and represents a promising therapeutic strategy for AD treatment. scyllo-Inositol (SI) is a potential therapeutic for AD by directly interacting with the Aß peptide to inhibit Aß42 fiber formation. Clinical studies of SI showed promising benefits on mild to moderate AD, however, with limitations on dosage regime. A new strategy to enhance the brain delivery of SI is needed to achieve the efficacy with minimum adverse effects. Herein, we report that a novel guanidine-appended SI derivative AAD-66 resulted in more effective reductions of brain Aß and plaque deposits, gliosis, and behavioral memory deficits in the disease-established 5xFAD mice. Overall, our present study reveals the potential of AAD-66 as a promising therapeutic agent for AD.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Encéfalo/metabolismo , Guanidina/química , Inositol/química , Inositol/farmacologia , Fenótipo , Doença de Alzheimer/complicações , Doença de Alzheimer/fisiopatologia , Peptídeos beta-Amiloides/metabolismo , Animais , Barreira Hematoencefálica/metabolismo , Cognição , Gliose/complicações , Inositol/metabolismo , Inositol/uso terapêutico , Camundongos , Camundongos Transgênicos
13.
Sci Rep ; 7(1): 11372, 2017 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-28900205

RESUMO

The apolipoprotein E4 (ApoE4) genotype combines with traumatic brain injury (TBI) to increase the risk of developing Alzheimer's Disease (AD). However, the underlying mechanism(s) is not well-understood. We found that after exposure to repetitive blast-induced TBI, phosphoinositol biphosphate (PIP2) levels in hippocampal regions of young ApoE3 mice were elevated and associated with reduction in expression of a PIP2 degrading enzyme, synaptojanin 1 (synj1). In contrast, hippocampal PIP2 levels in ApoE4 mice did not increase after blast TBI. Following blast TBI, phospho-Tau (pTau) levels were unchanged in ApoE3 mice, whereas in ApoE4 mice, levels of pTau were significantly increased. To determine the causal relationship between changes in pTau and PIP2/synj1 levels after TBI, we tested if down-regulation of synj1 prevented blast-induced Tau hyper-phosphorylation. Knockdown of synj1 decreased pTau levels in vitro, and abolished blast-induced elevation of pTau in vivo. Blast TBI increased glycogen synthase kinase (GSK)-3ß activities in ApoE4 mice, and synj1 knockdown inhibited GSK3ß phosphorylation of Tau. Together, these data suggest that ApoE proteins regulate brain phospholipid homeostasis in response to TBI and that the ApoE4 isoform is dysfunctional in this process. Down-regulation of synj1 rescues blast-induced phospholipid dysregulation and prevents development of Tau hyper-phosphorylation in ApoE4 carriers.


Assuntos
Apolipoproteína E4/genética , Lesões Encefálicas Traumáticas/metabolismo , Fosfolipídeos/metabolismo , Proteínas tau/metabolismo , Animais , Apolipoproteína E3/genética , Apolipoproteína E3/metabolismo , Apolipoproteína E4/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Lesões Encefálicas Traumáticas/etiologia , Lesões Encefálicas Traumáticas/patologia , Linhagem Celular , Hipocampo/metabolismo , Camundongos , Camundongos Transgênicos , Monoéster Fosfórico Hidrolases/metabolismo , Fosforilação
14.
Nature ; 549(7673): 523-527, 2017 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-28959956

RESUMO

APOE4 is the strongest genetic risk factor for late-onset Alzheimer disease. ApoE4 increases brain amyloid-ß pathology relative to other ApoE isoforms. However, whether APOE independently influences tau pathology, the other major proteinopathy of Alzheimer disease and other tauopathies, or tau-mediated neurodegeneration, is not clear. By generating P301S tau transgenic mice on either a human ApoE knock-in (KI) or ApoE knockout (KO) background, here we show that P301S/E4 mice have significantly higher tau levels in the brain and a greater extent of somatodendritic tau redistribution by three months of age compared with P301S/E2, P301S/E3, and P301S/EKO mice. By nine months of age, P301S mice with different ApoE genotypes display distinct phosphorylated tau protein (p-tau) staining patterns. P301S/E4 mice develop markedly more brain atrophy and neuroinflammation than P301S/E2 and P301S/E3 mice, whereas P301S/EKO mice are largely protected from these changes. In vitro, E4-expressing microglia exhibit higher innate immune reactivity after lipopolysaccharide treatment. Co-culturing P301S tau-expressing neurons with E4-expressing mixed glia results in a significantly higher level of tumour-necrosis factor-α (TNF-α) secretion and markedly reduced neuronal viability compared with neuron/E2 and neuron/E3 co-cultures. Neurons co-cultured with EKO glia showed the greatest viability with the lowest level of secreted TNF-α. Treatment of P301S neurons with recombinant ApoE (E2, E3, E4) also leads to some neuronal damage and death compared with the absence of ApoE, with ApoE4 exacerbating the effect. In individuals with a sporadic primary tauopathy, the presence of an ε4 allele is associated with more severe regional neurodegeneration. In individuals who are positive for amyloid-ß pathology with symptomatic Alzheimer disease who usually have tau pathology, ε4-carriers demonstrate greater rates of disease progression. Our results demonstrate that ApoE affects tau pathogenesis, neuroinflammation, and tau-mediated neurodegeneration independently of amyloid-ß pathology. ApoE4 exerts a 'toxic' gain of function whereas the absence of ApoE is protective.


Assuntos
Apolipoproteína E4/metabolismo , Apolipoproteína E4/toxicidade , Tauopatias/metabolismo , Tauopatias/patologia , Proteínas tau/metabolismo , Alelos , Animais , Apolipoproteína E4/deficiência , Apolipoproteína E4/genética , Sobrevivência Celular/efeitos dos fármacos , Técnicas de Cocultura , Modelos Animais de Doenças , Progressão da Doença , Técnicas de Introdução de Genes , Genótipo , Humanos , Imunidade Inata , Inflamação/genética , Inflamação/metabolismo , Inflamação/patologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Microglia/imunologia , Microglia/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Fosfoproteínas/análise , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Fosforilação , Tauopatias/genética , Fator de Necrose Tumoral alfa/metabolismo , Proteínas tau/genética
15.
Acta Biochim Biophys Sin (Shanghai) ; 49(5): 450-457, 2017 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-28338958

RESUMO

The cDNAs encoding antimicrobial peptides (AMPs) in the skin of Hylarana guentheri were identified, namely temporin (five peptides, termed temporin-GHa-GHd and temporin-GUa), brevinin-1 (one peptide, brevinin-1GUb), and brevinin-2 (eight peptides, brevinin-2GHd-2GHj, and brevinin-2GHb). Eleven of the 14 peptides have novel primary structures. Synthesized temporin GHa-GHd have broad-spectrum antimicrobial activities against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), Gram-negative bacteria (Escherichia coli, Vibrio alginolyticus, and Pseudomonas aeruginosa), as well as fungus (Candida albicans). Among these tested strains, S. aureus was the most sensitive to temporin-GHa-GHd with minimum inhibitory concentration (MIC) values between 6.8 and 12.9 µM. They also exhibited antimicrobial activities against Methicillin-resistant S. aureus with the MIC ranging from 12.7 to 51.7 µM. Interestingly, secondary structure prediction shows that there is no α-helix in temporin-GHb, which illustrates that α-helix is not required for the antimicrobial activity of temporin-GHb. NaCl (at final concentrations of 0.15-2 M) decreased the antimicrobial activity of temporin-GHa-GHd slightly, while human serum and S. aureus V8 proteinase had no effect on the antimicrobial activity. Scanning electron microscopy images of E. coli and S. aureus showed that the surface of microbial cells was considerably rough and shrived after 1 h of treatment with temporin-GHa-GHd at 37°C. The stabilities of temporin-GHa-GHd in human serum or in S. aureus V8 proteinase make them to be promising candidates of novel antimicrobial agents or models for the development of novel AMPs.


Assuntos
Peptídeos Catiônicos Antimicrobianos/administração & dosagem , Peptídeos Catiônicos Antimicrobianos/química , Fenômenos Fisiológicos Bacterianos/efeitos dos fármacos , Ranidae/metabolismo , Pele/metabolismo , Sequência de Aminoácidos , Animais , Antibacterianos/administração & dosagem , Peptídeos Catiônicos Antimicrobianos/metabolismo , Apoptose/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Clonagem Molecular , Dados de Sequência Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo
17.
Neuron ; 90(4): 724-39, 2016 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-27196974

RESUMO

Haplodeficiency of the microglia gene TREM2 increases risk for late-onset Alzheimer's disease (AD) but the mechanisms remain uncertain. To investigate this, we used high-resolution confocal and super-resolution (STORM) microscopy in AD-like mice and human AD tissue. We found that microglia processes, rich in TREM2, tightly surround early amyloid fibrils and plaques promoting their compaction and insulation. In Trem2- or DAP12-haplodeficient mice and in humans with R47H TREM2 mutations, microglia had a markedly reduced ability to envelop amyloid deposits. This led to an increase in less compact plaques with longer and branched amyloid fibrils resulting in greater surface exposure to adjacent neurites. This was associated with more severe neuritic tau hyperphosphorylation and axonal dystrophy around amyloid deposits. Thus, TREM2 deficiency may disrupt the formation of a neuroprotective microglia barrier that regulates amyloid compaction and insulation. Pharmacological modulation of this barrier could be a novel therapeutic strategy for AD.


Assuntos
Axônios/patologia , Glicoproteínas de Membrana/metabolismo , Microglia/metabolismo , Placa Amiloide/metabolismo , Receptores Imunológicos/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Amiloide/genética , Peptídeos beta-Amiloides/genética , Animais , Modelos Animais de Doenças , Humanos , Glicoproteínas de Membrana/deficiência , Camundongos , Mutação/genética , Neuritos/patologia , Placa Amiloide/genética , Receptores Imunológicos/deficiência
18.
Proc Natl Acad Sci U S A ; 113(19): 5412-7, 2016 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-27114525

RESUMO

The components involved in cellular trafficking and protein recycling machinery that have been associated with increased Alzheimer's disease (AD) risk belong to the late secretory compartments for the most part. Here, we hypothesize that these late unavoidable events might be the consequence of earlier complications occurring while amyloid precursor protein (APP) is trafficking through the early secretory pathway. We investigated the relevance to AD of coat protein complex I (COPI)-dependent trafficking, an early step in Golgi-to-endoplasmic reticulum (ER) retrograde transport and one of the very first trafficking steps. Using a complex set of imaging technologies, including inverse fluorescence recovery after photobleaching (iFRAP) and photoactivatable probes, coupled to biochemical experiments, we show that COPI subunit δ (δ-COP) affects the biology of APP, including its subcellular localization and cell surface expression, its trafficking, and its metabolism. These findings demonstrate the crucial role of δ-COP in APP metabolism and, consequently, the generation of amyloid-ß (Aß) peptide, providing previously nondescribed mechanistic explanations of the underlying events.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Membrana Celular/metabolismo , Proteína Coatomer/metabolismo , Neurônios/metabolismo , Frações Subcelulares/metabolismo , Animais , Linhagem Celular , Humanos , Camundongos , Transporte Proteico/fisiologia
19.
J Cereb Blood Flow Metab ; 36(1): 241-52, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25920959

RESUMO

Hypertension (HTN) doubles the risk of Alzheimer's disease (AD), but the mechanisms remain unclear. Amyloid-ß (Aß), a key pathogenic factor in AD, induces cerebrovascular dysfunction. We hypothesized that HTN acts in concert with Aß to amplify its deleterious cerebrovascular effects and to increase Aß production. Infusion of angiotensin II (ANGII; intravenously) elevated blood pressure and attenuated the cerebral blood flow (CBF) response to whisker stimulation or the endothelium-dependent vasodilator acetylcholine (ACh) (P < 0.05). Neocortical application of Aß in mice receiving ANGII worsened the responses to ACh (P < 0.05). The cerebrovascular dysfunction observed in Tg2576 mice, in which Aß is elevated both in blood and in brain due to expression of mutated amyloid precursor protein (APP), was not aggravated by neocortical application of ANGII or by a 2-week administration of 'slow pressor' of ANGII (600 ng/kg per minute; subcutaneously). In contrast, ANGII aggravated the dysfunction in TgSwDI mice, in which Aß is increased only in brain. Slow-pressor ANGII induced microvascular amyloid deposition in Tg2576 mice and enhanced ß-secretase APP cleavage. In Chinese hamster ovary (CHO) cells producing Aß, ANGII increased ß-secretase activity, Aß1-42, and the Aß42/40 ratio. We conclude that HTN enhances amyloidogenic APP processing, effects that may contribute to the pathogenic interaction between HTN and AD.


Assuntos
Doença de Alzheimer/patologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Angiopatia Amiloide Cerebral/patologia , Hipertensão/patologia , Doença de Alzheimer/etiologia , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/sangue , Peptídeos beta-Amiloides/farmacologia , Precursor de Proteína beta-Amiloide/sangue , Precursor de Proteína beta-Amiloide/metabolismo , Angiotensina II/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Células CHO , Angiopatia Amiloide Cerebral/etiologia , Angiopatia Amiloide Cerebral/metabolismo , Circulação Cerebrovascular/efeitos dos fármacos , Cricetulus , Modelos Animais de Doenças , Hipertensão/complicações , Hipertensão/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos
20.
Sci Rep ; 5: 11161, 2015 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-26057852

RESUMO

Microglia have been shown to contribute to the clearance of brain amyloid ß peptides (Aß), the major component of amyloid plaques, in Alzheimer's disease (AD). However, it is not known whether microglia play a similar role in the clearance of tau, the major component of neurofibrillary tangles (NFTs). We now report that murine microglia rapidly internalize and degrade hyperphosphorylated pathological tau isolated from AD brain tissue in a time-dependent manner in vitro. We further demonstrate that microglia readily degrade human tau species released from AD brain sections and eliminate NFTs from brain sections of P301S tauopathy mice. The anti-tau monoclonal antibody MC1 enhances microglia-mediated tau degradation in an Fc-dependent manner. Our data identify a potential role for microglia in the degradation and clearance of pathological tau species in brain and provide a mechanism explaining the potential therapeutic actions of passively administered anti-tau monoclonal antibodies.


Assuntos
Anticorpos Monoclonais/imunologia , Microglia/metabolismo , Proteínas tau/metabolismo , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Animais , Camundongos , Microglia/patologia , Proteólise , Proteínas tau/imunologia
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