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1.
Curr Protoc ; 1(10): e253, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34661993

RESUMO

The amyloid-ß (Aß) peptides of 40 and 42 amino acids that are implicated in Alzheimer's disease may potentially aggregate into toxic oligomers and form neuritic plaques. The enzyme-linked immunosorbent assay (ELISA) is a facile method used for the determination of Aß concentrations in biological matrices, namely plasma, cerebrospinal fluid, and brain. The method is mostly used for the measurement of Aß concentrations in transgenic mice, but it is unknown whether the ELISA method is suitable for measuring low, endogenous levels of Aß in the brains of wild-type mice. The Aß ELISA kit manufacturer recommends use of 5 M guanidine hydrochloride (GuHCl), a protein-denaturing agent, for homogenization of the brain tissue, followed by dilution back down to 0.1 M to avoid quenching by GuHCl. Components of brain matrices and GuHCl that could interfere with the quantitation have not been investigated. In this article, we describe an improved method involving homogenization of mouse brain with 1 M instead of 5 M GuHCl, reducing the dilution factor by 5× to provide a higher sensitivity. The modified ELISA assay is improved for the quantitation of brain Aß peptides in wild-type mice, where Aß peptide levels are much lower than those in transgenic mouse models. © 2021 Wiley Periodicals LLC.


Assuntos
Peptídeos beta-Amiloides , Placa Amiloide , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/metabolismo , Ensaio de Imunoadsorção Enzimática , Camundongos , Camundongos Transgênicos
2.
Ann Palliat Med ; 10(9): 10062-10074, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34551578

RESUMO

OBJECTIVE: In this review, we aim to provide an overview of the imaging techniques most commonly used to study Alzheimer's disease (AD). BACKGROUND: Neuroimaging biomarkers can be used to evaluate these abnormalities, improve the ability of early diagnosis and help predict disease progression. These signs mainly include local brain atrophy on structural MRI, hypometabolic foci, and amyloid plaque deposition in the brain detected by specific imaging. These techniques not only have their unique advantages, but can complement each other in multimodal imaging evaluation of patients with cognitive impairment and dementia. METHODS: A literature search was performed on PubMed using the search term combinations "Alzheimer's disease", "Amyloid-beta plaques", and "MRI". We discuss various magnetic resonance imaging (MRI) based techniques, including direct imaging, indirect imaging, amyloid-beta (Aß) plaque and radiomics, Hybrid PET/MRI and MRI imaging technology in the future, placing a special emphasis on multimodal imaging, and focus our review on the MRI features of Aß plaques (AD biomarkers). CONCLUSIONS: After a lot of research and reasonable selection, multimodal imaging composed of MRI and PET can significantly improve the diagnosis and treatment of AD patients, and the complementary information can be obtained by the new PET/MR instrument at the same time. The findings of this review emphasize that multimodal imaging is likely to be the preferred method for future AD research and clinical practice.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Doença de Alzheimer/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Neuroimagem , Placa Amiloide/diagnóstico por imagem
3.
Medicine (Baltimore) ; 100(35): e27055, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34477136

RESUMO

ABSTRACT: This study aimed to assess the longitudinal changes in amyloid beta (Aß) deposition in cortical regions with [11C]-PIB PET in initially amyloid-negative non-demented subjects and evaluate whether amyloid-negative subjects convert to amyloid-positive.Sixteen cognitively normal (CN) and 7 mild cognitive impairment (MCI) subjects (aged 60-75 years), who were amyloid-negative at baseline, underwent 60-minute dynamic [11C]-PIB PET and cognitive assessment over 5.0 to 9.4 years of a long follow-up, and the apolipoprotein-E (APOE) genotype was assessed. Regions of interest were defined in the bilateral cortex on coregistered MRI. Quantitative analysis of [11C]-PIB was performed using the distribution value ratio (DVR). Longitudinal changes in global and regional PIB DVRs were evaluated in the same regions, and the annual rate of change in the PIB DVR was calculated.Seven (30.4%) of 23 initially amyloid-negative non-demented subjects converted to globally amyloid-positive (global PIB DVR ≥1.40) over a follow-up of 6.5 ±â€Š1.4 years (converter). The global PIB DVR in converters increased from 1.22 ±â€Š0.07 at baseline to 1.63 ±â€Š0.15 (n = 7, P < .01) at last follow-up, and an annual increase of global PIB DVR was 0.057 ±â€Š0.019/year (n = 7, P < .01). In contrast, the global PIB DVR in the remaining 16 subjects was 1.15 ±â€Š0.07 at baseline and did not change over a follow-up period (stable). The APOE ε4 allele was present in 4 (57.1%) of the 7 converters, differing from 2 (12.5%) of 16 stable subjects (Fisher's exact test, P < .05). Three amyloid-negative MCI subjects had an annual increase in global PIB DVR above 0.061/year and became positive at 2.8 ±â€Š0.5 years of follow-up, which was faster than 5.0 ±â€Š2.0 years in 4 CN subjects. The regional PIB DVR that increased early above the regional positivity threshold was most frequently found in the right lateral temporal cortex (71.4%), followed by the left frontal cortex (41.8%).Our results suggest that the initially amyloid-negative CN and MCI subjects, especially with APOE ε4, can become globally amyloid-positive over a longer time, based on early regional Aß deposition in the lateral temporal cortex and/or frontal cortex.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Peptídeos beta-Amiloides/análise , Placa Amiloide/complicações , Idoso , Doença de Alzheimer/fisiopatologia , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Placa Amiloide/fisiopatologia , Tomografia por Emissão de Pósitrons/métodos , Tomografia por Emissão de Pósitrons/estatística & dados numéricos
4.
Analyst ; 146(19): 6014-6025, 2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34505596

RESUMO

The deposition of amyloid plaques is considered one of the main microscopic features of Alzheimer's disease (AD). Since plaque formation can precede extensive neurodegeneration and it is the main clinical manifestation of AD, it constitutes a relevant target for new treatment and diagnostic approaches. Micro-Raman spectroscopy, a label-free technique, is an accurate method for amyloid plaque identification and characterization. Here, we present a high spatial resolution micro-Raman hyperspectral study in transgenic APPswePS1ΔE9 mouse brains, showing details of AD tissue biochemical and histological changes without staining. First we used stimulated micro-Raman scattering to identify the lipid-rich halo surrounding the amyloid plaque, and then proceeded with spontaneous (conventional) micro-Raman spectral mapping, which shows a cholesterol and sphingomyelin lipid-rich halo structure around dense-core amyloid plaques. The detailed images of this lipid halo relate morphologically well with dystrophic neurites surrounding plaques. Principal Component Analysis (PCA) of the micro-Raman hyperspectral data indicates the feasibility of the optical biomarkers of AD progression with the potential for discriminating transgenic groups of young adult mice (6-month-old) from older ones (12-month-old). Frequency-specific PCA suggests that plaque-related neurodegeneration is the predominant change captured by Raman spectroscopy, and the main differences are highlighted by vibrational modes associated with cholesterol located majorly in the lipid halo.


Assuntos
Doença de Alzheimer , Placa Amiloide , Envelhecimento , Doença de Alzheimer/diagnóstico , Peptídeos beta-Amiloides , Animais , Encéfalo , Lipídeos , Camundongos , Camundongos Transgênicos , Análise Espectral Raman
5.
Zhen Ci Yan Jiu ; 46(9): 763-8, 2021 Sep 25.
Artigo em Chinês | MEDLINE | ID: mdl-34558242

RESUMO

OBJECTIVE: To compare the effect of electroacupuncture (EA), metformin and EA plus metformin on the cognitive ability and senile plaques (SPs) in cerebral cortex and hippocampus of Alzheimer's disease (AD) mice, so as to explore a better treatment method for AD. METHODS: Twenty-four male APP/PS1 mice were randomly divided into model, metformin (medication), EA and EA+medication groups, with 6 mice in each group. Other 6 male wild C57 mice were used as the control group. EA (2 Hz, 1.0 mA) was applied to "Baihui" (GV20) and "Shenshu" (BL23) for 15 min, once a day, for 4 weeks, with 1 day's off every week. The mice of the medication group received gavage of metformin (300 mg·kg-1·d-1) once a day for 4 weeks. Morris water maze tests were used to assess the cognitive function of mice. H.E. staining was used to observe the histopathological changes of neurons in the cortex and hippocampus. Immunohistochemical method was used to observe the cerebral cortex and hippocampal SPs. The expression levels of SPs formation-related proteins: ß-site amyloid precursor protein cleaving enzyme 1(ßACE1) and insulin-degrading enzyme (IDE) in the cortex and hippocampus were detected by Western blot. RESULTS: Compared with the control group, the escape latency, number of SPs and the expression of ßACE1 in the cortex and hippocampus were ob-viously increased (P<0.01), and the times of platform quadrant crossing and the expression of IDE protein were markedly decreased in the model group (P<0.01). In comparison with the model group, the escape latency, and the number of SPs and expression of ßACE1 proteins in the cortex and hippocampus in the 3 treatment groups were significantly down-regulated (P<0.01), while the times of platform quadrant crossing, and the expression of IDE protein in both cortex and hippocampus of the three treatment groups were considerably up-regulated (P<0.01). Comparison among the three treatment groups showed that the therapeutic effect of EA+medication was significantly superior to that of medication and simple EA in down-regulating the escape latency, the number of SPs and expression of ßACE1 in the cortex and hippocampus (P<0.01), and in up-regulating the times of the platform quadrant crossing, and expression of IDE protein in both cortex and hippocampus (P<0.01). No significant differences were found between the simple medication and simple EA in all the indexes mentioned above (P>0.05). CONCLUSION: EA, metformin and EA plus metformin can improve cognitive ability and relieve SP formation in cerebral cortex and hippocampus in AD mice, which may be associated with their functions in down-regulating the expression of ßACE1 and up-regulating the expression of IDE. The therapeutic effects of EA plus metformin are apparently better than those of simple EA and simple metformin.


Assuntos
Eletroacupuntura , Metformina , Animais , Córtex Cerebral , Cognição , Hipocampo , Masculino , Camundongos , Placa Amiloide
7.
Nat Commun ; 12(1): 5220, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34471104

RESUMO

Advancement in human induced pluripotent stem cell (iPSC) neuron and microglial differentiation protocols allow for disease modeling using physiologically relevant cells. However, iPSC differentiation and culturing protocols have posed challenges to maintaining consistency. Here, we generated an automated, consistent, and long-term culturing platform of human iPSC neurons, astrocytes, and microglia. Using this platform we generated a iPSC AD model using human derived cells, which showed signs of Aß plaques, dystrophic neurites around plaques, synapse loss, dendrite retraction, axon fragmentation, phospho-Tau induction, and neuronal cell death in one model. We showed that the human iPSC microglia internalized and compacted Aß to generate and surround the plaques, thereby conferring some neuroprotection. We investigated the mechanism of action of anti-Aß antibodies protection and found that they protected neurons from these pathologies and were most effective before pTau induction. Taken together, these results suggest that this model can facilitate target discovery and drug development efforts.


Assuntos
Doença de Alzheimer/metabolismo , Astrócitos/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Microglia/metabolismo , Neurônios/metabolismo , Diferenciação Celular , Humanos , Cinética , Placa Amiloide , Sinapses/metabolismo
8.
ACS Chem Neurosci ; 12(19): 3708-3718, 2021 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-34505762

RESUMO

Alzheimer's disease is associated with the deposition of extracellular senile plaques, made primarily of amyloid-ß (Aß), particularly peptides Aß1-42 and Aß1-40. Neprilysin, or neutral endopeptidase (NEP), catalyzes proteolysis of the amyloid peptides (Aß) and is recognized as one of the major regulators of the levels of these peptides in the brain, preventing Aß accumulation and plaque formation. Here, we used a combination of techniques to elucidate the mechanism of Aß binding and cleavage by NEP. Our findings indicate that the Aß31-X cleavage products remain bound to the neprilysin active site, reducing proteolytic activity. Interestingly, it was already shown that this Aß31-35 sequence is also critical for recognition of Aß peptides by other targets, such as the serpin-enzyme complex receptor in neuronal cells.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Amiloide , Humanos , Neprilisina , Placa Amiloide
9.
ACS Chem Neurosci ; 12(19): 3719-3732, 2021 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-34519476

RESUMO

Protein citrullination (deimination of arginine residue) is a well-known biomarker of inflammation. Elevated protein citrullination has been shown to colocalize with extracellular amyloid plaques in postmortem AD patient brains. Amyloid-ß (Aß) peptides which aggregate and accumulate in the plaques of Alzheimer's disease (AD) have sequential N-terminal truncations and multiple post-translational modifications (PTM) such as isomerization, pyroglutamate formation, phosphorylation, nitration, and dityrosine cross-linking. However, no conclusive biochemical evidence exists whether citrullinated Aß is present in AD brains. In this study, using high-resolution mass spectrometry, we have identified citrullination of Aß in sporadic and familial AD brains by characterizing the tandem mass spectra of endogenous N-truncated citrullinated Aß peptides. Our quantitative estimations demonstrate that ∼ 35% of pyroglutamate3-Aß pool was citrullinated in plaques in the sporadic AD temporal cortex and ∼ 22% in the detergent-insoluble frontal cortex fractions. Similarly, hypercitrullinated pyroglutamate3-Aß (∼ 30%) was observed in both the detergent-soluble as well as insoluble Aß pool in familial AD cases. Our results indicate that a common mechanism for citrullination of Aß exists in both the sporadic and familial AD. We establish that citrullination of Aß is a remarkably common PTM, closely associated with pyroglutamate3-Aß formation and its accumulation in AD. This may have implications for Aß toxicity, autoantigenicity of Aß, and may be relevant for the design of diagnostic assays and therapeutic targeting.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Peptídeos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Citrulinação , Humanos , Placa Amiloide
10.
ACS Chem Neurosci ; 12(19): 3625-3637, 2021 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-34524791

RESUMO

The pathological amyloid plaques in Alzheimer's disease (AD) patients contain not only the wild-type ß-amyloid (wt-Aß) peptide sequences but also a variety of post-translationally modified variants. The pyroglutamate-3 Aß (pyroE3-Aß), which is generated from its truncated precursors ΔE3-Aß, shows the highest abundance among all modified Aß variants. Previous works have shown that pyroE3-Aß and/or ΔE3-Aß, compared with the wild-type sequences, led to a more rapid fibrillation process and final fibrils with higher neuronal cytotoxicity levels. However, much less is known about how the formation of pyroE3/ΔE3-Aß fibrils would affect the amyloid deposition of wt-Aß peptides, which are the main pathological events in AD. We show in the present work that the pyroE3/ΔE3-Aß40 fibrils differ significantly from the wt-Aß40 fibrils in terms of their molecular structures. When added into monomeric wt-Aß40 peptides, these variant fibrils can cross-seed the formation of wt-Aß40 fibrils with fibrillation kinetics that are greater than the self-seeded fibrillation of wt-Aß40. Furthermore, the cross-seeding process modulates the molecular structures of the yielded wt-Aß40 fibrils, which show similar features as their variant seeds. The cross-seeded fibrillation process also induces higher cytotoxicity levels compared with the self-seeded fibrillation of wt-Aß40. Overall, our results support the hypothesis that pyroE3 and ΔE3-Aß40 variants may serve as triggering factors of the pathological amyloid aggregation of wt-Aß40 and may underlie the pathological significance of pyroE3/ΔE3-Aß40 variants on the structural polymorphism of Aß deposits.


Assuntos
Doença de Alzheimer , Ácido Pirrolidonocarboxílico , Doença de Alzheimer/genética , Amiloide , Peptídeos beta-Amiloides , Humanos , Placa Amiloide
11.
Int J Mol Sci ; 22(17)2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34502467

RESUMO

Alzheimer's disease (AD) is a chronic neurodegenerative disorder. This study was designed to investigate the effects of cyclopentanone derivative i.e., 2-(hydroxyl-(3-nitrophenyl)methyl)cyclopentanone (3NCP) on behavior, amyloid ß (Aß) plaque deposition, and ßAPP cleaving enzyme-1 (BACE-1) expression in the 5xFAD mouse brain. In this study, computational studies were conducted to predict the binding mode of the 3NCP with target sites of the ß-secretase. In vivo studies were performed on the 5xFAD mice model of AD using different behavioral test models like light/dark box, elevated plus maze (EPM), and the Barnes maze tests for the assessment of anxiety, spatial learning and memory. The thioflavin-S staining, immunohistochemistry (IHC), and RT-PCR studies were carried out to find the effect of the 3NCP on the ß-amyloid plaques formation and BACE-1 expression. The results of the computational studies showed that the 3NCP has excellent binding affinities for beta-secretase. The light/dark box study depicted that the 3NCP does not cause anxiety. The 3NCP treatment effects in the EPM and Barnes maze tests showed a significant effect on learning and memory. Furthermore, the results of the thioflavin staining and IHC revealed that the 3NCP significantly reduced the formation of the beta-amyloid plaques in brain tissues. Moreover, the RT-PCR study showed that 3NCP significantly reduced the BACE-1 expression in the brain. Conclusively, the results of the current study demonstrate that the 3NCP may be a potential candidate for AD treatment in the future.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Ciclopentanos/farmacologia , Transtornos da Memória/tratamento farmacológico , Placa Amiloide/tratamento farmacológico , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Animais , Modelos Animais de Doenças , Transtornos da Memória/genética , Transtornos da Memória/metabolismo , Transtornos da Memória/patologia , Camundongos , Camundongos Transgênicos , Placa Amiloide/genética , Placa Amiloide/metabolismo , Placa Amiloide/patologia
14.
ACS Chem Neurosci ; 12(18): 3418-3432, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34464082

RESUMO

Characterization of amyloid ß (Aß) oligomers, the transition species present prior to the formation of Aß fibrils and that have cytotoxicity, has become one of the major topics in the investigations of Alzheimer's disease (AD) pathogenesis. However, studying pathophysiological properties of Aß oligomers is challenging due to the instability of these protein complexes in vitro. Here, we report that conformation-restricted Aß42 with an intramolecular disulfide bond at positions 17 and 28 (SS-Aß42) formed stable Aß oligomers in vitro. Thioflavin T binding assays, nondenaturing gel electrophoresis, and morphological analyses revealed that SS-Aß42 maintained oligomeric structure, whereas wild-type Aß42 and the highly aggregative Aß42 mutant with E22P substitution (E22P-Aß42) formed Aß fibrils. In agreement with these observations, SS-Aß42 was more cytotoxic compared to the wild-type and E22P-Aß42 in cell cultures. Furthermore, we developed a monoclonal antibody, designated TxCo-1, using the toxic conformation of SS-Aß42 as immunogen. X-ray crystallography of the TxCo-1/SS-Aß42 complex, enzyme immunoassay, and immunohistochemical studies confirmed the recognition site and specificity of TxCo-1 to SS-Aß42. Immunohistochemistry with TxCo-1 antibody identified structures resembling senile plaques and vascular Aß in brain samples of AD subjects. However, TxCo-1 immunoreactivity did not colocalize extensively with Aß plaques identified with conventional Aß antibodies. Together, these findings indicate that Aß with a turn at positions 22 and 23, which is prone to form Aß oligomers, could show strong cytotoxicity and accumulated in brains of AD subjects. The SS-Aß42 and TxCo-1 antibody should facilitate understanding of the pathological role of Aß with toxic conformation in AD.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Amiloide , Peptídeos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Humanos , Fragmentos de Peptídeos , Placa Amiloide
15.
Exp Gerontol ; 153: 111502, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34339821

RESUMO

The excessive deposition of ß-amyloid proteins (Aß) is directly correlated with the establishment and development of Alzheimer's Disease (AD). Current treatments for AD only reduce symptoms instead of acting on Aß, the primary etiological agent. Hence, the anti-amyloid effect of regular exercise has been widely investigated as an alternative therapy. This systematic review and meta-analysis examined the anti-amyloid effect of regular physical exercise in animal models of AD. The search was conducted on the electronic databases Pubmed, Embase, Scopus and Web of Science without data limitation and using the following describers: "amyloid beta" (OR senile plaque OR amyloid plaque) and "exercise" (OR physical activity OR training). The risk of bias was evaluated using the SYRCLE's tool. Meta-analyses were conducted using models of random continuous effects. A total of 36 studies were selected and most used: transgenic mice (n = 29), treadmill training, duration of 12 weeks (interval of 4 to 28 weeks), rate of 60 min/day (interval of 30 min and up until free access) and speed of 12 m/min (interval of 3.2 to 32 m/min). The hippocampus and cortex were the most frequently investigated regions. Meta-analysis demonstrated a decrease in Aß with greater effect in unspecified isoforms Meta-analysis demonstrated a decrease in Aß with greater effect in unspecified isoforms (N = 4; SMD = -2.71, IC 95%: -3.59, -1.84, p < 0.00001, Q2 = 3.38, I2 = 11%) and Aß1-42 (N = 21; SMD = -1.94, IC 95%: -2.37, -1.51, p < 0.00001, Q2 = 33,37, I2 = 40%). Concerning training, greater effect was found with: 1) swimming (N = 4; SMD = -1.98, IC 95%: -3,28 - -0,68, p = 0.003, Q2 = 9.74, I2 = 69%), 2) moderate intensity (N = 4; SMD = -2.03, IC 95%: -3.31 - -0.75, p < 0.005, Q2 = 12.68, I2 = 76%); 3) duration up to six weeks (N = 6; N = 6; SMD = -2.35, IC 95%: -3.15 - -1.55, p < 0.00001, Q2 = 8.38, I2 = 40%); 4) young animals (SMD = -2.00, IC 95%: -2.59 - -1.42, p < 0.00001, Q2 = 24.90, I2 = 52%); 5) in the amygdala region (N = 1; SMD = -8.56, IC 95%: -12.88 - -4.23, p = 0.0001) and females (N = 4; SMD = -2.14, IC 95%: -3.48 - -0.79, p = 0.002, Q2 = 10.31, I2 = 71%). However, the reduction of Aß was associated with decrease of amyloidogenic pathway and increase of non-amyloidogenic. Hence, regular physical exercise demonstrated anti-amyloid effect in experimental models of AD through positive alterations in APP processing through different signaling pathways.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Doença de Alzheimer/terapia , Precursor de Proteína beta-Amiloide , Animais , Modelos Animais de Doenças , Exercício Físico , Feminino , Camundongos , Camundongos Transgênicos , Modelos Teóricos , Placa Amiloide
17.
Int J Mol Sci ; 22(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34360951

RESUMO

Epidemiological studies have implied that the nonsteroidal anti-inflammatory drug (NSAID) indomethacin slows the development and progression of Alzheimer's disease (AD). However, the underlying mechanisms are notably understudied. Using a chimeric mouse/human amyloid precursor protein (Mo/HuAPP695swe) and a mutant human presenilin 1 (PS1-dE9) (APP/PS1) expressing transgenic (Tg) mice and neuroblastoma (N) 2a cells as in vivo and in vitro models, we revealed the mechanisms of indomethacin in ameliorating the cognitive decline of AD. By screening AD-associated genes, we observed that a marked increase in the expression of α2-macroglobulin (A2M) was markedly induced after treatment with indomethacin. Mechanistically, upregulation of A2M was caused by the inhibition of cyclooxygenase-2 (COX-2) and lipocalin-type prostaglandin D synthase (L-PGDS), which are responsible for the synthesis of prostaglandin (PG)H2 and PGD2, respectively. The reduction in PGD2 levels induced by indomethacin alleviated the suppression of A2M expression through a PGD2 receptor 2 (CRTH2)-dependent mechanism. Highly activated A2M not only disrupted the production and aggregation of ß-amyloid protein (Aß) but also induced Aß efflux from the brain. More interestingly, indomethacin decreased the degradation of the A2M receptor, low-density lipoprotein receptor-related protein 1 (LRP1), which facilitated the brain efflux of Aß. Through the aforementioned mechanisms, indomethacin ameliorated cognitive decline in APP/PS1 Tg mice by decreasing Aß production and clearing Aß from the brains of AD mice.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Anti-Inflamatórios não Esteroides/farmacologia , Indometacina/farmacologia , Placa Amiloide/tratamento farmacológico , alfa-Macroglobulinas/metabolismo , Animais , Anti-Inflamatórios não Esteroides/uso terapêutico , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Linhagem Celular Tumoral , Ciclo-Oxigenase 2/metabolismo , Humanos , Indometacina/uso terapêutico , Oxirredutases Intramoleculares/metabolismo , Lipocalinas/metabolismo , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Placa Amiloide/metabolismo , Receptores Imunológicos/metabolismo , Receptores de Prostaglandina/metabolismo , Regulação para Cima , alfa-Macroglobulinas/genética
18.
Nutrients ; 13(7)2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34371921

RESUMO

The study of different natural products can provide a wealth of bioactive compounds, and more interestingly, their combination can exert a new strategy for several neurodegenerative diseases with major public health importance, such as Alzheimer's disease (AD). Here, we investigated the synergistic neuroprotective effects of a mixed extract composed of docosahexaenoic acid, Ginkgo biloba, D-pinitol, and ursolic acid in several transgenic Caenorhabditis elegans (C. elegans) and a senescence-accelerated prone mice 8 (SAMP8) model. First, we found a significantly higher survival percentage in the C. elegans group treated with the natural product mixture compared to the single extract-treated groups. Likewise, we found a significantly increased lifespan in group of C. elegans treated with the natural product mixture compared to the other groups, suggesting synergistic effects. Remarkably, we determined a significant reduction in Aß plaque accumulation in the group of C. elegans treated with the natural product mixture compared to the other groups, confirming synergy. Finally, we demonstrated better cognitive performance in the group treated with the natural product mixture in both AD models (neuronal Aß C. elegans strain CL2355 and the SAMP8 mice model), confirming the molecular results and unraveling the synergist effects of this combination. Therefore, our results proved the potential of this new natural product mixture for AD therapeutic strategies.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Comportamento Animal/efeitos dos fármacos , Produtos Biológicos/farmacologia , Encéfalo/efeitos dos fármacos , Cognição/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Doença de Alzheimer/psicologia , Peptídeos beta-Amiloides/metabolismo , Animais , Animais Geneticamente Modificados , Encéfalo/metabolismo , Encéfalo/patologia , Caenorhabditis elegans/genética , Modelos Animais de Doenças , Longevidade , Camundongos , Neurônios/metabolismo , Neurônios/patologia , Estresse Oxidativo/efeitos dos fármacos , Placa Amiloide
20.
Exp Brain Res ; 239(9): 2821-2839, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34283253

RESUMO

Insulin deficiency or resistance can promote dementia and hallmarks of Alzheimer's disease (AD). The formation of neurofibrillary tangles of p-TAU protein, extracellular Aß plaques, and neuronal loss is related to the switching off insulin signaling in cognition brain areas. Metformin is a biguanide antihyperglycemic drug used worldwide for the treatment of type 2 diabetes. Some studies have demonstrated that metformin exerts neuroprotective, anti-inflammatory, anti-oxidant, and nootropic effects. This study aimed to evaluate metformin's effects on long-term memory and p-Tau and amyloid ß modulation, which are hallmarks of AD in diabetic mice. Swiss Webster mice were distributed in the following experimental groups: control; treated with streptozotocin (STZ) that is an agent toxic to the insulin-producing beta cells; STZ + metformin 200 mg/kg (M200). STZ mice showed significant augmentation of time spent to reach the target box in the Barnes maze, while M200 mice showed a significant time reduction. Moreover, the M200 group showed reduced GFAP immunoreactivity in hippocampal dentate gyrus and CA1 compared with the STZ group. STZ mice showed high p-Tau levels, reduced p-CREB, and accumulation of ß-amyloid (Aß) plaque in hippocampal areas and corpus callosum. In contrast, all these changes were reversed in the M200 group. Protein expressions of p-Tau, p-ERK, pGSK3, iNOS, nNOS, PARP, Cytochrome c, caspase 3, and GluN2A were increased in the parietal cortex of STZ mice and significantly counteracted in M200 mice. Moreover, M200 mice also showed significantly high levels of eNOS, AMPK, and p-AKT expression. In conclusion, metformin improved spatial memory in diabetic mice, which can be associated with reducing p-Tau and ß-amyloid (Aß) plaque load and inhibition of neuronal death.


Assuntos
Doença de Alzheimer , Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Metformina , Doença de Alzheimer/complicações , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides , Animais , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/tratamento farmacológico , Modelos Animais de Doenças , Metformina/farmacologia , Camundongos , Camundongos Transgênicos , Placa Amiloide , Proteínas tau
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