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1.
Rev Neurosci ; 26(4): 371-83, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25879319

RESUMO

A growing body of evidence has linked two of the most common aged-related diseases: type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD). It has led to the notion that drugs developed for the treatment of T2DM may be beneficial in modifying the pathophysiology of AD. As a receptor agonist of glucagon-like peptide-1 (GLP-1R), which is a newer drug class to treat T2DM, geniposide shows clear effects in inhibiting pathological processes underlying AD, such as promoting neurite outgrowth. In the present article, we review the possible molecular mechanisms of geniposide to protect the brain from pathologic damages underlying AD: reducing amyloid plaques, inhibiting τ phosphorylation, preventing memory impairment and loss of synapses, reducing oxidative stress and the chronic inflammatory response, and promoting neurite outgrowth via the GLP-1R signaling pathway. In summary, the Chinese herb geniposide shows great promise as a novel treatment for AD.


Assuntos
Doença de Alzheimer/prevenção & controle , Iridoides/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Doença de Alzheimer/complicações , Doença de Alzheimer/patologia , Animais , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/patologia , Humanos , Iridoides/farmacologia , Fármacos Neuroprotetores/farmacologia
2.
Phys Rev Lett ; 115(19): 198103, 2015 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-26588419

RESUMO

A Caulobacter crescentus swarmer cell is propelled by a helical flagellum, which is rotated by a motor at its base. The motor alternates between rotating in clockwise and counterclockwise directions and spends variable intervals of time in each state. We measure the distributions of these intervals for cells either free swimming or tethered to a glass slide. A peak time of around one second is observed in the distributions for both motor directions with counterclockwise intervals more sharply peaked and clockwise intervals displaying a larger tail at long times. We show that distributions of rotation intervals fit first passage time statistics for a biased random walker and the dynamic binding of CheY-P to FliM motor subunits accounts for this behavior. Our results also suggest that the presence of multiple CheY proteins in C. crescentus may be responsible for differences between its switching behavior and that of the extensively studied E. coli.


Assuntos
Caulobacter crescentus/fisiologia , Flagelos/fisiologia , Modelos Biológicos , Proteínas de Bactérias/fisiologia , Proteínas de Escherichia coli , Proteínas de Membrana/fisiologia , Proteínas Quimiotáticas Aceptoras de Metil , Modelos Estatísticos , Proteínas Motores Moleculares/fisiologia
3.
BMC Microbiol ; 14: 322, 2014 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-25539737

RESUMO

BACKGROUND: Motility of flagellated bacteria depends crucially on their organelles such as flagella and pili, as well as physical properties of the external medium, such as viscosity and matrix elasticity. We studied the motility of wild-type and two mutant strains of Caulobacter crescentus swarmer cells in two different types of media: a viscous and hyperosmotic glycerol-growth medium mixture and a viscoelastic growth medium, containing polyethylene glycol or polyethylene oxide of different defined sizes. RESULTS: For all three strains in the medium containing glycerol, we found linear drops in percentage of motile cells and decreases in speed of those that remained motile to be inversely proportional to viscosity. The majority of immobilized cells lost viability, evidenced by their membrane leakage. In the viscoelastic media, we found less loss of motility and attenuated decrease of swimming speed at shear viscosity values comparable to the viscous medium. In both types of media, we found more severe loss in percentage of motile cells of wild-type than the mutants without pili, indicating that the interference of pili with flagellated motility is aggravated by increased viscosity. However, we found no difference in swimming speed among all three strains under all test conditions for the cells that remained motile. Finally, the viscoelastic medium caused no significant change in intervals between flagellar motor switches unless the motor stalled. CONCLUSION: Hyperosmotic effect causes loss of motility and cell death. Addition of polymers into the cell medium also causes loss of motility due to increased shear viscosity, but the majority of immobilized bacteria remain viable. Both viscous and viscoelastic media alter the motility of flagellated bacteria without affecting the internal regulation of their motor switching behavior.


Assuntos
Caulobacter crescentus/fisiologia , Meios de Cultura/química , Elasticidade , Locomoção , Viscosidade , Viabilidade Microbiana , Pressão Osmótica
4.
Biophys J ; 105(1): 21-8, 2013 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-23823220

RESUMO

Microbes inhabiting Earth have adapted to diverse environments of water, air, soil, and often at the interfaces of multiple media. In this study, we focus on the behavior of Caulobacter crescentus, a singly flagellated bacterium, at the air/water interface. Forward swimming C. crescentus swarmer cells tend to get physically trapped at the surface when swimming in nutrient-rich growth medium but not in minimal salt motility medium. Trapped cells move in tight, clockwise circles when viewed from the air with slightly reduced speed. Trace amounts of Triton X100, a nonionic surfactant, release the trapped cells from these circular trajectories. We show, by tracing the motion of positively charged colloidal beads near the interface that organic molecules in the growth medium adsorb at the interface, creating a high viscosity film. Consequently, the air/water interface no longer acts as a free surface and forward swimming cells become hydrodynamically trapped. Added surfactants efficiently partition to the surface, replacing the viscous layer of molecules and reestablishing free surface behavior. These findings help explain recent similar studies on Escherichia coli, showing trajectories of variable handedness depending on media chemistry. The consistent behavior of these two distinct microbial species provides insights on how microbes have evolved to cope with challenging interfacial environments.


Assuntos
Ar , Caulobacter crescentus/citologia , Movimento , Água , Adsorção , Microscopia , Propriedades de Superfície
5.
Mol Microbiol ; 83(1): 41-51, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22053824

RESUMO

The attachment of bacteria to surfaces provides advantages such as increasing nutrient access and resistance to environmental stress. Attachment begins with a reversible phase, often mediated by surface structures such as flagella and pili, followed by a transition to irreversible attachment, typically mediated by polysaccharides. Here we show that the interplay between pili and flagellum rotation stimulates the rapid transition between reversible and polysaccharide-mediated irreversible attachment. We found that reversible attachment of Caulobacter crescentus cells is mediated by motile cells bearing pili and that their contact with a surface results in the rapid pili-dependent arrest of flagellum rotation and concurrent stimulation of polar holdfast adhesive polysaccharide. Similar stimulation of polar adhesin production by surface contact occurs in Asticcacaulis biprosthecum and Agrobacterium tumefaciens. Therefore, single bacterial cells respond to their initial contact with surfaces by triggering just-in-time adhesin production. This mechanism restricts stable attachment to intimate surface interactions, thereby maximizing surface attachment, discouraging non-productive self-adherence, and preventing curing of the adhesive.


Assuntos
Adesinas Bacterianas/metabolismo , Caulobacter crescentus/fisiologia , Adesinas Bacterianas/genética , Aderência Bacteriana , Caulobacter crescentus/genética , Fímbrias Bacterianas/genética , Fímbrias Bacterianas/metabolismo , Flagelos/genética , Flagelos/metabolismo , Regulação Bacteriana da Expressão Gênica
6.
BMC Microbiol ; 13: 139, 2013 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-23777390

RESUMO

BACKGROUND: Adhesion to surfaces facilitates many crucial functions of microbes in their natural habitats. Thus understanding the mechanism of microbial adhesion is of broad interest to the microbiology research community. RESULTS: We report a study by fluorescence imaging and atomic force microscopy on the growth in size and thickness of the holdfast of synchronized Caulobacter crescentus cells as they attach to a glass surface. We found that the holdfast undergoes a two-stage process of spreading and thickening during its morphogenesis. The holdfast first forms a thin plate on the surface. The diameter of the holdfast plate reaches its final average value of 360 nm by the cell age of ~ 30 min, while its thickness further increases until the age of ~ 60 min. Our AFM analysis indicates that the holdfast is typically thicker in the middle, with gradual falloff in thickness towards the outer edge. CONCLUSIONS: We propose that the newly secreted holdfast substance is fluid-like. It has strong affinity to the surface and cures to form a plate-like holdfast capable of supporting strong and permanent adhesion.


Assuntos
Aderência Bacteriana , Caulobacter crescentus/fisiologia , Caulobacter crescentus/crescimento & desenvolvimento , Processamento de Imagem Assistida por Computador , Microscopia de Força Atômica , Microscopia de Fluorescência
7.
J Am Chem Soc ; 134(32): 13410-4, 2012 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-22816386

RESUMO

Monodisperse 11 nm indium tin oxide (ITO) nanocrystals (NCs) were synthesized by thermal decomposition of indium acetylacetonate, In(acac)(3), and tin bis(acetylacetonate)dichloride, Sn(acac)(2)Cl(2), at 270 °C in 1-octadecene with oleylamine and oleic acid as surfactants. Dispersed in hexane, these ITO NCs were spin-cast on centimeter-wide glass substrates, forming uniform ITO NC assemblies with root-mean-square roughness of 2.9 nm. The assembly thickness was controlled by ITO NC concentrations in hexane and rotation speeds of the spin coater. Via controlled thermal annealing at 300 °C for 6 h under Ar and 5% H(2), the ITO NC assemblies became conductive and transparent with the 146 nm-thick assembly showing 5.2 × 10(-3) Ω·cm (R(s) = 356 Ω/sq) resistivity and 93% transparency in the visible spectral range--the best values ever reported for ITO NC assemblies prepared from solution phase processes. The stable hexane dispersion of ITO NCs was also readily spin-cast on polyimide (T(g) ~360 °C), and the resultant ITO assembly exhibited a comparable conductivity and transparency to the assembly on a glass substrate. The reported synthesis and assembly provide a promising solution to the fabrication of transparent and conducting ITO NCs on flexible substrates for optoelectronic applications.

8.
Environ Sci Technol ; 46(6): 3220-7, 2012 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-22352378

RESUMO

Most nanomaterials enter the natural environment as nanoenabled products, which are typically composites with primary nanoparticles bound on substrates or embedded in liquid or solid matrices. The environmental risks associated with these products are expected to differ from those associated with the as-produced particles. This article presents a case study on the end-of-life emission of a commercial prototype polymer/quantum-dot (QD) composite used in solid-state lighting for homes. We report the extent of cadmium release upon exposure to a series of environmental and biological simulant fluids, and track the loss of QD-characteristic fluorescence as a marker for chemical damage to the CdSe/ZnS nanoparticles. Measured cadmium releases after 30-day exposure range from 0.007 to 1.2 mg/g of polymer, and the higher values arise for low-pH simulants containing nitric or gastric acid. Centrifugal ultrafiltration and ICP was used to distinguish soluble cadmium from particulate forms. The leachate is found to contain soluble metals with no evidence of free QDs or QD-containing polymeric debris. The absence of free nanoparticles suggests that this product does not raise nanotechnology-specific environmental issues associated with degradation and leaching, but is more usefully regarded as a conventional chemical product that is a potential source of small amounts of soluble cadmium.


Assuntos
Compostos de Cádmio/química , Cádmio/análise , Iluminação , Nanocompostos/química , Pontos Quânticos , Compostos de Selênio/química , Sulfetos/química , Compostos de Zinco/química , Benzopiranos/química , Qualidade de Produtos para o Consumidor , Ácido Gástrico/química , Substâncias Húmicas , Peróxido de Hidrogênio/química , Microscopia de Fluorescência , Ácido Nítrico/química , Oxidantes/química , Cloreto de Sódio/química , Água/química
9.
Zhong Yao Cai ; 35(7): 1022-5, 2012 Jul.
Artigo em Zh | MEDLINE | ID: mdl-23252260

RESUMO

OBJECTIVE: To explore the influence of the storage conditions on the seed development of Corydalis yanhusuo. METHODS: The embryo formation process of the wild Corydalis yanhusuo was observed,and the germination rate of wild Corydalis yanhusuo seeds stored under different conditions was measured. RESULTS: The seed development of the wild Corydalis yanhusuo depended on the storage conditions. The seeds subjected to stratification had the highest germination percentage. Those stored in dry conditions would lose the vitality completely. The seeds in isothermal storage had very low germination rates. As revealed by slices, only the seeds after stratification treatment had the ability to form a complete embryo. CONCLUSION: The Corydalis yanhusuo seed is a kind of seed without fully developed embryo, and needs further after-ripening for its development. Its vitality has a great seasonal and annual dependence.


Assuntos
Corydalis/embriologia , Corydalis/crescimento & desenvolvimento , Germinação/fisiologia , Sementes/crescimento & desenvolvimento , Corydalis/fisiologia , Plantas Medicinais/crescimento & desenvolvimento , Plantas Medicinais/fisiologia , Plântula/crescimento & desenvolvimento , Sementes/fisiologia , Temperatura , Fatores de Tempo
10.
J Bacteriol ; 193(11): 2695-707, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21441504

RESUMO

Bacterial flagella play key roles in surface attachment and host-bacterial interactions as well as driving motility. Here, we have investigated the ability of Caulobacter crescentus to assemble its flagellar filament from six flagellins: FljJ, FljK, FljL, FljM, FljN, and FljO. Flagellin gene deletion combinations exhibited a range of phenotypes from no motility or impaired motility to full motility. Characterization of the mutant collection showed the following: (i) that there is no strict requirement for any one of the six flagellins to assemble a filament; (ii) that there is a correlation between slower swimming speeds and shorter filament lengths in ΔfljK ΔfljM mutants; (iii) that the flagellins FljM to FljO are less stable than FljJ to FljL; and (iv) that the flagellins FljK, FljL, FljM, FljN, and FljO alone are able to assemble a filament.


Assuntos
Caulobacter crescentus/fisiologia , Flagelos/metabolismo , Flagelina/genética , Flagelina/metabolismo , Substâncias Macromoleculares/metabolismo , Caulobacter crescentus/genética , Flagelos/ultraestrutura , Deleção de Genes , Genes Bacterianos , Locomoção , Substâncias Macromoleculares/ultraestrutura , Microscopia Eletrônica
11.
Proc Natl Acad Sci U S A ; 105(47): 18355-9, 2008 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-19015518

RESUMO

Brownian motion influences bacterial swimming by randomizing displacement and direction. Here, we report that the influence of Brownian motion is amplified when it is coupled to hydrodynamic interaction. We examine swimming trajectories of the singly flagellated bacterium Caulobacter crescentus near a glass surface with total internal reflection fluorescence microscopy and observe large fluctuations over time in the distance of the cell from the solid surface caused by Brownian motion. The observation is compared with computer simulation based on analysis of relevant physical factors, including electrostatics, van der Waals force, hydrodynamics, and Brownian motion. The simulation reproduces the experimental findings and reveals contribution from fluctuations of the cell orientation beyond the resolution of present observation. Coupled with hydrodynamic interaction between the bacterium and the boundary surface, the fluctuations in distance and orientation subsequently lead to variation of the swimming speed and local radius of curvature of swimming trajectory. These results shed light on the fundamental roles of Brownian motion in microbial motility, nutrient uptake, and adhesion.


Assuntos
Caulobacter crescentus/fisiologia , Aderência Bacteriana , Microscopia de Fluorescência , Modelos Biológicos
12.
Acta Neurochir (Wien) ; 153(2): 319-25, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20686796

RESUMO

BACKGROUND: Heme oxygenase-1 (HO-1), the rate-limiting enzyme for heme catabolism and iron production, its role in intracerebral hemorrhage (ICH) is controversial. The study was to investigate correlations between brain oxidative injury and HO-1 after experimental ICH. METHOD: Sprague-Dawley rats received intra-striatal infusions of 100 µl autologous whole blood as ICH models. HO-1 were examined by immunohistochemical and reverse transcription polymerase chain reaction (RT-PCR) analysis. Brain oxidative stress was quantitated by malondialdehyde (MDA); antioxidation were measured by copper-zinc superoxide dismutase (Cu/Zn-SOD) activity using RT-PCR assay. RESULTS: The expression of the HO-1 upregulated and reached its peak at days 3 and 7 after ICH (P < 0.01). There was a significant increase of MDA and a top at 3-day post-ICH (P < 0.01); Cu/Zn-SOD was upregulated post-ICH and reached the top at day 7 (P < 0.001); HO-1 was correlated significantly with brain MDA content at days 7 and 14 following ICH (r = 0.435-0.501, P < 0.001) but there is no definite correlation between them on 1 to 3 days (P > 0.05); conversely, HO-1 was correlated significantly with Cu/Zn-SOD on 1 to 3 days after ICH (r = 0.433-0.621, P < 0.001) but there is no definite correlation between them at days 7 and 14 (P > 0.05). CONCLUSIONS: HO-1 has both antioxidant and prooxidant properties in ICH. The early upregulation of HO-1 possibly fit with the events and be protective against oxidative stress, whereas its overexpression in the late stages may result in its dysfunction and be toxic. So it should be prudent to intervene ICH with the inhibitor/activator of HO-1.


Assuntos
Hemorragia Cerebral/enzimologia , Heme Oxigenase (Desciclizante)/fisiologia , Degeneração Neural/enzimologia , Estresse Oxidativo/fisiologia , Animais , Hemorragia Cerebral/complicações , Hemorragia Cerebral/patologia , Modelos Animais de Doenças , Feminino , Heme Oxigenase (Desciclizante)/genética , Masculino , Degeneração Neural/etiologia , Degeneração Neural/patologia , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
13.
Neuropharmacology ; 158: 107748, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31465784

RESUMO

Stroke is a condition with few medical treatments available. Semaglutide, a novel Glucagon-like peptide-1 (GLP-1) analogue, has been brought to the market as a treatment for diabetes. We tested the protective effects of semaglutide against middle cerebral artery occlusion injury in rats. Animals were treated with 10 nmol/kg bw ip. starting 2 h after surgery and every second day for either 1, 7, 14 or 21 days. Semaglutide-treated animals showed significantly reduced scores of neurological impairments in several motor and grip strength tasks. The cerebral infarction size was also reduced, and the loss of neurons in the hippocampal areas CA1, CA3 and the dentate gyrus was much reduced. Chronic inflammation as seen in levels of activated microglia and in the activity of the p38 MAPK - MKK - c-Jun- NF-κB p65 inflammation signaling pathway was reduced. In addition, improved growth factor signaling as shown in levels of activated ERK1 and IRS-1, and a reduction in the apoptosis signaling pathway C-raf, ERK2, Bcl-2/BAX and Caspase-3 was observed. Neurogenesis had also been normalized by the drug treatment as seen in increased neurogenesis (DCX-positive cells) in the dentate gyrus and a normalization of biomarkers for neurogenesis. In conclusion, semaglutide is a promising candidate for re-purposing as a stroke treatment.


Assuntos
Apoptose/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Peptídeos Semelhantes ao Glucagon/farmacologia , Hipocampo/efeitos dos fármacos , Hipoglicemiantes/farmacologia , Infarto da Artéria Cerebral Média/patologia , Neurogênese/efeitos dos fármacos , Animais , Encéfalo/imunologia , Encéfalo/patologia , Modelos Animais de Doenças , Proteína Duplacortina , Peptídeo 1 Semelhante ao Glucagon/análogos & derivados , Hipocampo/citologia , Infarto da Artéria Cerebral Média/imunologia , Infarto da Artéria Cerebral Média/fisiopatologia , Inflamação/imunologia , Proteínas Substratos do Receptor de Insulina/efeitos dos fármacos , Proteínas Substratos do Receptor de Insulina/metabolismo , Microglia/efeitos dos fármacos , Microglia/imunologia , Proteína Quinase 3 Ativada por Mitógeno/efeitos dos fármacos , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/efeitos dos fármacos , Quinases de Proteína Quinase Ativadas por Mitógeno/imunologia , Atividade Motora/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-jun/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-jun/imunologia , Ratos , Acidente Vascular Cerebral/imunologia , Acidente Vascular Cerebral/patologia , Acidente Vascular Cerebral/fisiopatologia , Fator de Transcrição RelA/efeitos dos fármacos , Fator de Transcrição RelA/imunologia , Proteínas Quinases p38 Ativadas por Mitógeno/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/imunologia
14.
Neuropharmacology ; 133: 385-394, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29462693

RESUMO

Type 2 diabetes mellitus (T2DM) is a risk factors for developing Parkinson's disease (PD). Insulin desensitization is observed in the brains of PD patients, which may be an underlying mechanism that promotes neurodegeneration. Incretin hormones are growth factors that can re-sensitize insulin signalling. We have previously shown that analogues of the incretins GLP-1 or GIP have neuroprotective effects in the MPTP mouse model of PD. Novel dual GLP-1/GIP receptor agonists have been developed as treatments for T2DM. We have tested 3 novel dual receptor agonists DA-JC1, DA-JC4 and DA-CH5 in comparison with the GLP-1 analogue liraglutide (all drugs at 25 nmol/kg ip once-daily for 6 days) in the MPTP mouse model of PD (4 × 25 mg/kg ip). In the Rotarod and grip strength assessment, DA-CH5 performed best in reversing the MPTP-induced motor impairment. Dopamine synthesis as indicated by levels of tyrosine hydroxylase was much reduced by MPTP in the substantia nigra and striatum, and DA-CH5 was the best drug to reverse this. Pro-inflammatory cytokines were best reduced by DA-CH5, while expression levels of the neuroprotective growth factor Glial-Derived Neurotrophic Factor (GDNF) was most increased by DA-JC4. Synapses were protected best by DA-JC4 and DA-CH5. Both DA-JC1 and liraglutide showed inferior effects. These results show that a combination of GLP-1 and GIP receptor activation is more efficient compared to single GLP-1 receptor activation. We conclude that dual agonists are a promising novel treatment for PD. The GLP-1 mimetic exendin-4 has previously shown disease modifying effects in two clinical trials in Parkinson patients.


Assuntos
Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Intoxicação por MPTP/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Peptídeos/uso terapêutico , Receptores dos Hormônios Gastrointestinais/agonistas , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/farmacologia , Animais , Glicemia/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Citocinas/metabolismo , Modelos Animais de Doenças , Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 1/química , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Hipoglicemiantes/uso terapêutico , Liraglutida/uso terapêutico , Camundongos , Camundongos Endogâmicos C57BL , Atividade Motora/efeitos dos fármacos , Neurotoxinas/toxicidade , Receptores dos Hormônios Gastrointestinais/química , Receptores dos Hormônios Gastrointestinais/metabolismo
15.
Eur J Pharmacol ; 812: 82-90, 2017 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-28666800

RESUMO

Type 2 diabetes mellitus (T2DM) is one of the risk factors for Parkinson's disease (PD). Insulin desensitisation has been observed in the brains of patients, which may promote neurodegeneration. Incretins are a family of growth factors that can re-sensitise insulin signalling. We have previously shown that mimetics of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) have neuroprotective effects in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropypridine (MPTP) mouse model of PD. Recently, dual GLP-1/GIP receptor agonists have been developed. We therefore tested the novel dual agonist DA3-CH in comparison with the best GLP-1 analogue currently on the market, liraglutide (both drugs 25nmol/kg ip once-daily for 7 days) in the MPTP mouse model of PD (25mg/kg ip once-daily for 7 days). In the Rotarod and grip strength assessment, DA3-CH was superior to liraglutide in reversing the MPTP-induced motor impairment. Dopamine synthesis as indicated by levels of tyrosine hydroxylase was much reduced by MPTP in the substantia nigra and striatum, and DA3-CH reversed this while liragutide only partially reversed this. The chronic inflammation response as shown in increased levels of activated microglia and astrocytes was reduced by both drugs. Importantly, expression levels of the neuroprotective growth factor Glial Derived Neurotrophic Factor (GDNF) was much enhanced by both DA3-CH and liragutide. The results demonstrate that the combination of GLP-1 and GIP receptor activation is superior to single GLP-1 receptor activation alone. Therefore, new dual agonists may be a promising treatment for PD. The GLP-1 receptor agonist exendin-4 has already shown disease modifying effects in clinical trials in PD patients.


Assuntos
1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/farmacologia , Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Liraglutida/farmacologia , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/metabolismo , Receptores dos Hormônios Gastrointestinais/agonistas , Animais , Glicemia/metabolismo , Peso Corporal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Dopamina/biossíntese , Força da Mão , Inflamação/tratamento farmacológico , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas dos Microfilamentos/metabolismo , Atividade Motora/efeitos dos fármacos , Doença de Parkinson/etiologia , Doença de Parkinson/fisiopatologia , Teste de Desempenho do Rota-Rod
16.
Neurosci Lett ; 618: 72-76, 2016 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-26940239

RESUMO

This study aimed to determine the effects of different concentrations of soluble beta-amyloid 25-35 (Aß25-35) on cell viability, calcium overload, and PI3K-p85 expression in cultured cortical rat neurons. Primary cultured cerebral cortical neurons of newborn rats were divided randomly into six groups. Five groups were treated with soluble Aß25-35 at concentrations of 10nmol/L, 100nmol/L, 1µmol/L, 10µmol/L, or 30µmol/L. Cell Counting Kit-8 staining was used to measure cell viability, laser-scanning confocal imaging was used to detect changes in intracellular free calcium concentration, and western blot assay was used to measure neuronal PI3K-p85 expression. Soluble Aß25-35 was found to reduce cell viability and induce calcium overload in primary cultured rat cerebral cortical neurons, in a concentration-dependent manner. At certain concentrations, soluble Aß25-35 also increased neuronal PI3K-p85 expression. These findings reveal that soluble Aß25-35 reduces the viability of cultured cerebral cortical rat neurons. The neurotoxicity mechanism may involve calcium overload and disruption of insulin signal transduction pathways.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Córtex Cerebral/metabolismo , Neurônios/metabolismo , Fragmentos de Peptídeos/metabolismo , Peptídeos beta-Amiloides/toxicidade , Animais , Animais Recém-Nascidos , Cálcio/metabolismo , Sobrevivência Celular , Córtex Cerebral/citologia , Córtex Cerebral/efeitos dos fármacos , Classe Ia de Fosfatidilinositol 3-Quinase/metabolismo , Insulina/fisiologia , Neurônios/citologia , Neurônios/efeitos dos fármacos , Fragmentos de Peptídeos/toxicidade , Cultura Primária de Células , Ratos Wistar , Transdução de Sinais , Solubilidade
17.
Neuroreport ; 27(1): 23-32, 2016 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-26555034

RESUMO

Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptor agonists have been shown to be neuroprotective in previous studies in animal models of Alzheimer's or Parkinson's disease. Recently, novel dual-GLP-1/GIP receptor agonists that activate both receptors (DA) were developed to treat diabetes. We tested the protective effects of a novel potent DA against middle cerebral artery occlusion injury in rats and compared it with a potent GLP-1 analog, Val(8)-GLP-1(glu-PAL). Animals were evaluated for neurologic deficit score, infarct volume, and immunohistochemical analyses of the brain at several time points after ischemia. The Val(8)-GLP-1(glu-PAL)-treated and DA-treated groups showed significantly reduced scores of neurological dysfunction, cerebral infarction size, and percentage of TUNEL-positive apoptotic neurons. Furthermore, the expression of the apoptosis marker Bax, the inflammation marker iNOS, and the survival marker Bcl-2 was significantly increased. The DA-treated group was better protected against neurodegeneration than the Val(8)-GLP-1(glu-PAL) group, and the scores of neurological dysfunction, cerebral infarction size, and expression of Bcl-2 were higher, whereas the percentage of TUNEL-positive neurons and the levels of Bax and iNOS were lower in the DA group. DA treatment reduced the infarct volume and improved the functional deficit. It also suppressed the inflammatory response and cell apoptosis after reperfusion. In conclusion, the novel GIP and GLP-1 dual-receptor agonist is more neuroprotective than a GLP-1 receptor agonist in key biomarkers of neuronal degeneration.


Assuntos
Encéfalo/efeitos dos fármacos , Peptídeo 1 Semelhante ao Glucagon/análogos & derivados , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Ataque Isquêmico Transitório/tratamento farmacológico , Lipopeptídeos/farmacologia , Receptores dos Hormônios Gastrointestinais/agonistas , Animais , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Encéfalo/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Peptídeo 1 Semelhante ao Glucagon/farmacologia , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Infarto da Artéria Cerebral Média , Ataque Isquêmico Transitório/complicações , Ataque Isquêmico Transitório/metabolismo , Ataque Isquêmico Transitório/patologia , Masculino , Atividade Motora/efeitos dos fármacos , Degeneração Neural/tratamento farmacológico , Degeneração Neural/etiologia , Degeneração Neural/metabolismo , Degeneração Neural/patologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Fármacos Neuroprotetores/farmacologia , Óxido Nítrico Sintase Tipo II/metabolismo , Distribuição Aleatória , Ratos Sprague-Dawley , Receptores dos Hormônios Gastrointestinais/metabolismo , Proteína X Associada a bcl-2/metabolismo
18.
Rev Neurosci ; 27(1): 61-70, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26351802

RESUMO

Glucose-dependent insulinotropic polypeptide (GIP) is a member of the incretin hormones and growth factors. Neurons express the GIP receptor, and GIP and its agonists can pass through the blood brain barrier and show remarkable neuroprotective effects by protecting synapse function and numbers, promoting neuronal proliferation, reducing amyloid plaques in the cortex and reducing the chronic inflammation response of the nervous system. Long-acting analogues of GIP that are protease resistant had been developed as a treatment for type 2 diabetes. It has been found that such GIP analogues show good protective effects in animal models of Alzheimer's disease. Novel dual agonist peptides that activate the GIP receptor and another incretin receptor, glucagon-like peptide -1 (GLP-1), are under development that show superior effects in diabetic patients compared to single GLP-1 agonists. The dual agonists also show great promise in treating neurodegenerative disorders, and there are currently several clinical trials ongoing, testing GLP-1 mimetics in people with Alzheimer's or Parkinson's disease.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Polipeptídeo Inibidor Gástrico/análogos & derivados , Fármacos Neuroprotetores/uso terapêutico , Doença de Alzheimer/prevenção & controle , Animais , Polipeptídeo Inibidor Gástrico/farmacologia , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Humanos , Fármacos Neuroprotetores/farmacologia , Receptores dos Hormônios Gastrointestinais/agonistas , Transdução de Sinais , Sinapses/efeitos dos fármacos
19.
Neural Regen Res ; 11(2): 326-31, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27073388

RESUMO

The growth factor glucagon-like peptide-1 (GLP-1) is neuroprotective in several animal models of neurodegeneration. Here, we analyzed the neuroprotective effects of a novel protease-resistant GLP-1 analogue, (Val(8))GLP-1-Glu-PAL, which has advantages over older analogues, such as improvement of hippocampal neurogenesis, glucose homeostasis, and insulin secretion. We established an in vitro model of Parkinson's disease using the mitochondrial stressor rotenone in primary cultured mouse neurons pretreated with (Val(8))GLP-1-Glu-PAL. (Val(8))GLP-1-Glu-PAL alone did not affect neuronal viability, but prevented the rotenone-induced reduction in cell viability in a dose-dependent manner. In addition, (Val(8))GLP-1-Glu-PAL pretreatment prevented rotenone-induced proapoptotic changes manifesting as downregulation of procaspase-3 and Bcl-2 and upregulation of cleaved caspase-3. These results demonstrate that the novel agent (Val(8))GLP-1-Glu-PAL shows promise as a drug treatment for Parkinson's disease.

20.
Brain Res ; 1634: 1-11, 2016 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26453833

RESUMO

The incretins glucagon-like peptide 1 (GLP-1) and glucose dependent insulinotropic polypeptide (GIP) are growth factors with neuroprotective properties. GLP-1 mimetics are on the market as treatments for type 2 diabetes and are well tolerated. Both GLP-1 and GIP mimetics have shown neuroprotective properties in animal models of Parkinson's and Alzheimer's disease. In addition, the GLP-1 mimetic exendin-4 has shown protective effects in a clinical trial in Parkinson's disease (PD) patients. Novel GLP-1/GIP dual-agonist peptides have been developed and are tested in diabetic patients. Here we demonstrate the neuroprotective effects of a novel dual agonist (DA-JC1) in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. MPTP was injected once-daily (20 mg/kg i.p.) for 7 days, and the dual agonist was injected 30 min later i.p. (50 nmol/kg bw). The PI3k inhibitor LY294002 (0.6 mg/kg i.v.) was co-injected in one group. DA-JC1 reduced or reversed most of the MPTP induced motor impairments in the rotarod and in a muscle strength test. The number of tyrosine hydroxylase (TH) positive neurons in the substantia nigra (SN) was reduced by MPTP and increased by DA-JC1. The ratio of anti-inflammatory Bcl-2 to pro-inflammatory BAX as well as the activation of the growth factor kinase Akt was reduced by MPTP and reversed by DA-JC1. The PI3k inhibitor had only limited effect on the DA-JC1 drug effect. Importantly, levels of the neuroprotective brain derived neurotropic factor (BDNF) were reduced by MPTP and enhanced by DA-JC1. The results demonstrate that DA-JC1 shows promise as a novel treatment for PD.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Fármacos Neuroprotetores/administração & dosagem , Transtornos Parkinsonianos/metabolismo , Receptores dos Hormônios Gastrointestinais/agonistas , Animais , Apoptose/efeitos dos fármacos , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Atividade Motora/efeitos dos fármacos , Força Muscular/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Transtornos Parkinsonianos/prevenção & controle , Proteínas Proto-Oncogênicas c-akt/metabolismo , Teste de Desempenho do Rota-Rod , Substância Negra/efeitos dos fármacos , Substância Negra/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismo
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