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1.
BMC Infect Dis ; 23(1): 847, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38041069

RESUMO

Research has shown that multidimensional approaches to Chagas disease (CD), integrating its biomedical and psycho-socio-cultural components, are successful in enhancing early access to diagnosis, treatment and sustainable follow-up.For the first time, a consulate was selected for a community-based CD detection campaign. Two different strategies were designed, implemented and compared between 2021 and 2022 at the Consulate General of Bolivia and a reference health facility in Barcelona open to all Bolivians in Catalonia.Strategy 1 consisted in CD awareness-raising activities before referring those interested to the reference facility for infectious disease screening. Strategy 2 offered additional in-situ serological CD screening. Most of the 307 participants were Bolivian women residents in Barcelona. In strategy 1, 73 people (35.8% of those who were offered the test) were screened and 19.2% of them were diagnosed with CD. Additionally, 53,4% completed their vaccination schedules and 28.8% were treated for other parasitic infections (strongyloidiasis, giardiasis, eosinophilia, syphilis). In strategy 2, 103 people were screened in-situ (100% of those who were offered the test) and 13.5% received a CD diagnosis. 21,4% completed their vaccination schedule at the reference health facility and 2,9% were referred for iron deficiency anemia, strongyloidiasis or chronic hepatitis C.The fact that the screening took place in an official workplace of representatives of their own country, together with the presence of community-based participants fueled trust and increased CD understanding. Each of the strategies assessed had different benefits. Opportunities for systematic integration for CD based on community action in consulates may enhance early access to diagnosis, care and disease prevention.


Assuntos
Doença de Chagas , Eosinofilia , Estrongiloidíase , Humanos , Feminino , Doença de Chagas/diagnóstico , Doença de Chagas/epidemiologia , Programas de Rastreamento , Participação da Comunidade
2.
Biochim Biophys Acta ; 1860(4): 746-56, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26774643

RESUMO

BACKGROUND: Amyloid ß (Aß) peptide aggregation is the main molecular mechanism underlying the development of Alzheimer's disease, the most widespread form of senile dementia worldwide. Increasing evidence suggests that the key factor leading to impaired neuronal function is accumulation of water-soluble Aß oligomers rather than formation of the senile plaques created by the deposition of large fibrillary aggregates of Aß. However, several questions remain about the preliminary steps and the progression of Aß oligomerization. METHODS: We show that the initial stages of the aggregation of fluorescently labeled Aß can be determined with a high degree of precision and at physiological (i.e., nanomolar) concentrations by using either steady-state fluorimetry or time-correlated single-photon counting. RESULTS: We study the dependence of the oligomerization extent and rate on the Aß concentration. We determine the chemical binding affinity of fluorescently labeled Aß for liposomes that have been recently shown to be pharmacologically active in vivo, reducing the Aß burden within the brain. We also probe their capacity to hinder the Aß oligomerization process in vitro. CONCLUSIONS: We introduced a fluorescence assay allowing investigation of the earliest steps of Aß oligomerization, the peptide involved in Alzheimer's disease. The assay proved to be sensitive even at Aß concentrations as low as those physiologically observed in the cerebrospinal fluid. GENERAL SIGNIFICANCE: This work represents an extensive and quantitative study on the initial events of Aß oligomerization at physiological concentration. It may enhance our comprehension of the molecular mechanisms leading to Alzheimer's disease, thus paving the way to novel therapeutic strategies.


Assuntos
Peptídeos beta-Amiloides/química , Lipossomos/química , Fragmentos de Peptídeos/química , Agregação Patológica de Proteínas , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Humanos , Fragmentos de Peptídeos/metabolismo , Espectrometria de Fluorescência
3.
Nanomedicine ; 13(2): 723-732, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27769888

RESUMO

Aggregation of amyloid-ß peptide (Aß) is a key event in the pathogenesis of Alzheimer's disease (AD). We investigated the effects of nanoliposomes decorated with the retro-inverso peptide RI-OR2-TAT (Ac-rGffvlkGrrrrqrrkkrGy-NH2) on the aggregation and toxicity of Aß. Remarkably low concentrations of these peptide inhibitor nanoparticles (PINPs) were required to inhibit the formation of Aß oligomers and fibrils in vitro, with 50% inhibition occurring at a molar ratio of ~1:2000 of liposome-bound RI-OR2-TAT to Aß. PINPs also bound to Aß with high affinity (Kd=13.2-50 nM), rescued SHSY-5Y cells from the toxic effect of pre-aggregated Aß, crossed an in vitro blood-brain barrier model (hCMEC/D3 cell monolayer), entered the brains of C57 BL/6 mice, and protected against memory loss in APPSWE transgenic mice in a novel object recognition test. As the most potent aggregation inhibitor that we have tested so far, we propose to develop PINPs as a potential disease-modifying treatment for AD.


Assuntos
Doença de Alzheimer/fisiopatologia , Doença de Alzheimer/terapia , Nanopartículas , Fragmentos de Peptídeos , Peptídeos beta-Amiloides , Animais , Barreira Hematoencefálica , Humanos , Lipossomos , Camundongos Transgênicos , Células Tumorais Cultivadas
4.
Nanomedicine ; 12(1): 43-52, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26410276

RESUMO

We previously showed the ability of liposomes bi-functionalized with phosphatidic acid and an ApoE-derived peptide (mApoE-PA-LIP) to reduce brain Aß in transgenic Alzheimer mice. Herein we investigated the efficacy of mApoE-PA-LIP to withdraw Aß peptide in different aggregation forms from the brain, using a transwell cellular model of the blood-brain barrier and APP/PS1 mice. The spontaneous efflux of Aß oligomers (Aßo), but not of Aß fibrils, from the 'brain' side of the transwell was strongly enhanced (5-fold) in presence of mApoE-PA-LIP in the 'blood' compartment. This effect is due to a withdrawal of Aßo exerted by peripheral mApoE-PA-LIP by sink effect, because, when present in the brain side, they did not act as Aßo carrier and limit the oligomer efflux. In vivo peripheral administration of mApoE-PA-LIP significantly increased the plasma Aß level, suggesting that Aß-binding particles exploiting the sink effect can be used as a therapeutic strategy for Alzheimer disease. From the Clinical Editor: Alzheimer disease (AD) at present is an incurable disease, which is thought to be caused by an accumulation of amyloid-ß (Aß) peptides in the brain. Many strategies in combating this disease have been focused on either the prevention or dissolving these peptides. In this article, the authors showed the ability of liposomes bi-functionalized with phosphatidic acid and with an ApoE- derived peptide to withdraw amyloid peptides from the brain. The data would help the future design of more novel treatment for Alzheimer disease.


Assuntos
Doença de Alzheimer/terapia , Peptídeos beta-Amiloides/isolamento & purificação , Peptídeos beta-Amiloides/metabolismo , Barreira Hematoencefálica/metabolismo , Nanopartículas/metabolismo , Nanopartículas/uso terapêutico , Doença de Alzheimer/metabolismo , Barreira Hematoencefálica/química , Células Cultivadas , Estudos de Viabilidade , Humanos , Nanopartículas/química
5.
Nanomedicine ; 11(2): 421-30, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25461285

RESUMO

The accumulation of extracellular amyloid-beta (Aß) peptide and intracellular neurofibrillary tangles in the brain are two major neuropathological hallmarks of Alzheimer's disease (AD). It is thought that an equilibrium exists between Aß in the brain and in the peripheral blood and thus, it was hypothesized that shifting this equilibrium towards the blood by enhancing peripheral clearance might reduce Aß levels in the brain: the 'sink effect'. We tested this hypothesis by intraperitoneally injecting APP/PS1 transgenic mice with small unilamellar vesicles containing either phosphatidic acid or cardiolipin over 3weeks. This treatment reduced significantly the amount of Aß in the plasma and the brain levels of Aß were lighter affected. Nevertheless, this dosing regimen did modulate tau phosphorylation and glycogen synthase kinase 3 activities in the brain, suggesting that the targeting of circulating Aß may be therapeutically relevant in AD. FROM THE CLINICAL EDITOR: Intraperitoneal injection of small unilamellar vesicles containing phosphatidic acid or cardiolipin significantly reduced the amount of amyloid-beta (Aß) peptide in the plasma in a rodent model. Brain levels of Aß were also affected - although to a lesser extent - suggesting that targeting of circulating Aß may be therapeutically relevant of Alzheimer's disease.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/sangue , Cardiolipinas/administração & dosagem , Ácidos Fosfatídicos/administração & dosagem , Doença de Alzheimer/sangue , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Precursor de Proteína beta-Amiloide/genética , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Cardiolipinas/química , Modelos Animais de Doenças , Quinase 3 da Glicogênio Sintase/metabolismo , Humanos , Injeções Intraperitoneais , Lipossomos/administração & dosagem , Lipossomos/química , Camundongos , Camundongos Transgênicos , Nanopartículas/administração & dosagem , Nanopartículas/química , Ácidos Fosfatídicos/química , Proteínas tau/metabolismo
6.
Biochem Soc Trans ; 42(3): 657-61, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24849234

RESUMO

Airway diseases including COPD (chronic obstructive pulmonary disease), cystic fibrosis and lung cancer are leading causes of worldwide morbidity and mortality, with annual healthcare costs of billions of pounds. True regeneration of damaged airways offers the possibility of restoring lung function and protecting against airway transformation. Recently, advances in tissue engineering have allowed the development of cadaveric and biosynthetic airway grafts. Although these have produced encouraging results, the ability to achieve long-term functional airway regeneration remains a major challenge. To promote regeneration, exogenously delivered stem and progenitor cells are being trialled as cellular therapies. Unfortunately, current evidence suggests that only small numbers of exogenously delivered stem cells engraft within lungs, thereby limiting their utility for airway repair. In other organ systems, magnetic targeting has shown promise for improving long-term robust cell engraftment. This technique involves in vitro cell expansion, magnetic actuation and magnetically guided cell engraftment to sites of tissue damage. In the present paper, we discuss the utility of coupling stem cell-mediated cellular therapy with magnetic targeting for improving airway regeneration.


Assuntos
Brônquios/fisiopatologia , Terapia Baseada em Transplante de Células e Tecidos , Fibrose Cística/fisiopatologia , Neoplasias Pulmonares/fisiopatologia , Magnetismo , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Regeneração , Traqueia/fisiopatologia , Humanos , Células-Tronco/citologia , Engenharia Tecidual
7.
Lancet Reg Health Eur ; 37: 100826, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38362555

RESUMO

Background: Ensuring that access to health care is affordable for everyone-financial protection-is central to universal health coverage (UHC). Financial protection is commonly measured using indicators of financial barriers to access (unmet need for health care) and financial hardship caused by out-of-pocket payments for health care (impoverishing and catastrophic health spending). We aim to assess financial hardship and unmet need in Europe and identify the coverage policy choices that undermine financial protection. Methods: We carry out a cross-sectional study of financial hardship in 40 countries in Europe in 2019 (the latest available year of data before COVID-19) using microdata from national household budget surveys. We define impoverishing health spending as out-of-pocket payments that push households below or further below a relative poverty line and catastrophic health spending as out-of-pocket payments that exceed 40% of a household's capacity to pay for health care. We link these results to survey data on unmet need for health care, dental care, and prescribed medicines and information on two aspects of coverage policy at country level: the main basis for entitlement to publicly financed health care and user charges for covered services. Findings: Out-of-pocket payments for health care lead to financial hardship and unmet need in every country in the study, particularly for people with low incomes. Impoverishing health spending ranges from under 1% of households (in six countries) to 12%, with a median of 3%. Catastrophic health spending ranges from under 1% of households (in two countries) to 20%, with a median of 6%. Catastrophic health spending is consistently concentrated in the poorest fifth of the population and is largely driven by out-of-pocket payments for outpatient medicines, medical products, and dental care-all forms of treatment that should be an essential part of primary care. The median incidence of catastrophic health spending is three times lower in countries that cover over 99% of the population than in countries that cover less than 99%. In 16 out of the 17 countries that cover less than 99% of the population, the basis for entitlement is payment of contributions to a social health insurance (SHI) scheme. Countries that give greater protection from user charges to people with low incomes have lower levels of catastrophic health spending. Interpretation: It is challenging to identify with certainty the coverage policy choices that undermine financial protection due to the complexity of the policies involved and the difficulty of disentangling the effects of different choices. The conclusions we draw are therefore tentative, though plausible. Countries are more likely to move towards UHC if they reduce out-of-pocket payments in a progressive way, decreasing them for people with low incomes first. Coverage policy choices that seem likely to achieve this include de-linking entitlement from payment of SHI contributions; expanding the coverage of outpatient medicines, medical products, and dental care; limiting user charges; and strengthening protection against user charges, particularly for people with low incomes. Funding: The European Union (DG SANTE and DG NEAR) and the Government of the Autonomous Community of Catalonia, Spain.

8.
Nat Commun ; 15(1): 5006, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38866738

RESUMO

Body mass results from a complex interplay between genetics and environment. Previous studies of the genetic contribution to body mass have excluded repetitive regions due to the technical limitations of platforms used for population scale studies. Here we apply genome-wide approaches, identifying an association between adult body mass and the copy number (CN) of 47S-ribosomal DNA (rDNA). rDNA codes for the 18 S, 5.8 S and 28 S ribosomal RNA (rRNA) components of the ribosome. In mammals, there are hundreds of copies of these genes. Inter-individual variation in the rDNA CN has not previously been associated with a mammalian phenotype. Here, we show that rDNA CN variation associates with post-pubertal growth rate in rats and body mass index in adult humans. rDNA CN is not associated with rRNA transcription rates in adult tissues, suggesting the mechanistic link occurs earlier in development. This aligns with the observation that the association emerges by early adulthood.


Assuntos
Índice de Massa Corporal , Variações do Número de Cópias de DNA , DNA Ribossômico , Animais , Humanos , DNA Ribossômico/genética , Masculino , Ratos , Feminino , Adulto , Mamíferos/genética , RNA Ribossômico/genética , RNA Ribossômico/metabolismo
9.
J Cell Biol ; 222(8)2023 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-37402211

RESUMO

Signaling through the inflammasome is important for the inflammatory response. Low concentrations of intracellular K+ are associated with the specific oligomerization and activation of the NLRP3 inflammasome, a type of inflammasome involved in sterile inflammation. After NLRP3 oligomerization, ASC protein binds and forms oligomeric filaments that culminate in large protein complexes named ASC specks. ASC specks are also initiated from different inflammasome scaffolds, such as AIM2, NLRC4, or Pyrin. ASC oligomers recruit caspase-1 and then induce its activation through interactions between their respective caspase activation and recruitment domains (CARD). So far, ASC oligomerization and caspase-1 activation are K+-independent processes. Here, we found that when there is low intracellular K+, ASC oligomers change their structure independently of NLRP3 and make the ASCCARD domain more accessible for the recruitment of the pro-caspase-1CARD domain. Therefore, conditions that decrease intracellular K+ not only drive NLRP3 responses but also enhance the recruitment of the pro-caspase-1 CARD domain into the ASC specks.


Assuntos
Proteínas Adaptadoras de Sinalização CARD , Caspase 1 , Inflamassomos , Potássio , Proteínas Adaptadoras de Sinalização CARD/genética , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Caspase 1/genética , Caspase 1/metabolismo , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Potássio/metabolismo , Domínios Proteicos
10.
Nanomedicine ; 8 Suppl 1: S51-8, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22640910

RESUMO

The efficacy, cellular uptake and specific transport of drugs and/or imaging agents to target organs, tissues and cells are common issues in the diagnosis and treatment of different disorders. In the case of neurodegenerative diseases, they represent complex problems, since brain targeting remains a still unsolved challenge in pharmacology, due to the presence of the blood-brain barrier, a tightly packed layer of endothelial cells that prevents unwanted substances to enter the brain. Engineered nanomaterials, objects with dimensions of 1-100 nm, are providing interesting biomedical tools potentially able to solve these problems, thanks to their physico-chemical features and to the possibility of multi-functionalization, allowing to confer them different features at the same time, including the ability to cross the blood-brain barrier. This review focuses on the state-of-the-art of nanomaterials suitable for therapy and diagnostic imaging of the most common neurodegenerative disorders, as well as for neuroprotection and neuronal tissue regeneration. Finally, their potential neurotoxicity is discussed, and future nanotechnological approaches are described.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Nanomedicina/métodos , Nanoestruturas/uso terapêutico , Doenças Neurodegenerativas/diagnóstico , Doenças Neurodegenerativas/terapia , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Humanos , Nanoestruturas/química , Nanoestruturas/toxicidade , Nanotecnologia/métodos , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia
11.
Neurochem Res ; 36(5): 863-9, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21287268

RESUMO

We investigated whether the toxicity of oligomeric amyloid-beta peptide (Abeta1-42) upon differentiated human neuroblastoma SH-SY5Y cells, can be affected by changes of membrane lipid composition. An immunostaining technique, using lipids extracted from the cells and separated by thin layer chromatography, suggested that Abeta preferentially binds to phosphatidylethanolamine (PE), one of the major lipids in the cell extract. For this reason, we utilized treatments with putative inhibitors of phosphatidylethanolamine biosynthesis (choline, phosphocholine, R59949) to decrease its proportion in the cell membrane; choline treatment (2.5 mM, 24 h) showed the best performance, reducing phosphatidylethanolamine content from 5.7 to 3.3 µg phosphorous/mg protein. Either the extent of Abeta binding or its toxicity decreased onto choline-treated cells. These data may open the possibility to develop future strategies aiming to reduce Abeta toxicity in Alzheimer disease.


Assuntos
Peptídeos beta-Amiloides/antagonistas & inibidores , Diferenciação Celular , Neuroblastoma/metabolismo , Fragmentos de Peptídeos/antagonistas & inibidores , Fosfatidiletanolaminas/metabolismo , Peptídeos beta-Amiloides/fisiologia , Linhagem Celular Tumoral , Cromatografia em Camada Fina , Humanos , Neuroblastoma/patologia , Fragmentos de Peptídeos/fisiologia
12.
Nanomedicine ; 7(5): 551-9, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21658472

RESUMO

A promising strategy to enhance blood-brain barrier penetration by drugs is the functionalization of nanocarriers with uptake-facilitating ligands. We studied the cellular uptake, by cultured RBE4 brain capillary endothelial cells, of nanoliposomes (NLs) covalently coupled with monomer or tandem dimer of apolipoprotein E (ApoE)-derived peptides (residues 141-150), at various densities. NLs without functionalization did not show either relevant membrane accumulation or cellular uptake, as monitored by confocal microscopy and quantified by fluorescence-activated cell sorting. Functionalization with peptides mediated an efficient NLs uptake that increased with peptide density; NLs carrying monomeric peptide performed the best. Moreover, we studied the ability of ApoE-NLs to enhance the transport of a drug payload through a RBE4 cell monolayer. The permeability of a tritiated curcumin derivative was enhanced after its entrapment into ApoE-NLs, in particular those functionalized with the dimer (+83% with respect to free drug, P < 0.01). Thus, these NLs appear particularly suitable for implementing further strategies for drug brain targeting.


Assuntos
Apolipoproteínas E/química , Barreira Hematoencefálica/metabolismo , Sistemas de Liberação de Medicamentos , Nanopartículas/administração & dosagem , Animais , Transporte Biológico , Encéfalo/metabolismo , Linhagem Celular , Curcumina/farmacocinética , Células Endoteliais/metabolismo , Citometria de Fluxo , Humanos , Lipossomos , Microscopia Confocal , Permeabilidade , Ratos
13.
Nanomedicine ; 7(5): 541-50, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21722618

RESUMO

The effect of various types of nanoliposomes (associated with curcumin, phosphatidic acid, cardiolipin, or GM1 ganglioside) on the aggregation of the amyloid-ß(1-42) (Aß(1-42)) peptide was investigated. Nanoliposomes incorporating curcumin (curcumin-liposomes) were prepared by adding curcumin in the lipid phase during liposome preparation, whereas curcumin surface-decorated liposomes were prepared by using a curcumin-lipid conjugate (lipid-S-curcumin liposomes) or by attaching a curcumin derivative on preformed liposomes by click chemistry (click-curcumin liposomes). The lipid ligands (phosphatidic acid, cardiolipin, or GM1) were also incorporated into nanoliposomes during their formation. All nanoliposomes with curcumin, or the curcumin derivative, were able to inhibit the formation of fibrillar and/or oligomeric Aß in vitro. Of the three forms of curcumin liposomes tested, the click-curcumin type was by far the most effective. Liposomes with lipid ligands only inhibited Aß fibril and oligomer formation at a very high ratio of liposome to peptide. Curcumin-based liposomes could be further developed as a novel treatment for Alzheimer's disease.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/antagonistas & inibidores , Curcumina/administração & dosagem , Nanopartículas/administração & dosagem , Fragmentos de Peptídeos/antagonistas & inibidores , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Cardiolipinas/química , Curcumina/química , Gangliosídeo G(M1)/química , Humanos , Ligantes , Lipossomos , Nanopartículas/química , Fragmentos de Peptídeos/metabolismo , Ácidos Fosfatídicos/química
14.
Neurooncol Adv ; 3(1): vdab076, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34377986

RESUMO

BACKGROUND: The radio- and chemo-resistance of glioblastoma stem-like cells (GSCs), together with their innate tumor-initiating aptitude, make this cell population a crucial target for effective therapies. However, targeting GSCs is hardly difficult and complex, due to the presence of the blood-brain barrier (BBB) and the infiltrative nature of GSCs arousing their dispersion within the brain parenchyma. METHODS: Liposomes (LIPs), surface-decorated with an Apolipoprotein E-modified peptide (mApoE) to enable BBB crossing, were loaded with doxorubicin (DOXO), as paradigm of cytotoxic drug triggering immunogenic cell death (ICD). Patient-derived xenografts (PDXs) obtained by GSC intracranial injection were treated with mApoE-DOXO-LIPs alone or concomitantly with radiation. RESULTS: Our results indicated that mApoE, through the engagement of the low-density lipoprotein receptor (LDLR), promotes mApoE-DOXO-LIPs transcytosis across the BBB and confers target specificity towards GSCs. Irradiation enhanced LDLR expression on both BBB and GSCs, thus further promoting LIP diffusion and specificity. When administered in combination with radiations, mApoE-DOXO-LIPs caused a significant reduction of in vivo tumor growth due to GSC apoptosis. GSC apoptosis prompted microglia/macrophage phagocytic activity, together with the activation of the antigen-presenting machinery crucially required for anti-tumor adaptive immune response. CONCLUSIONS: Our results advocate for radiotherapy and adjuvant administration of drug-loaded, mApoE-targeted nanovectors as an effective strategy to deliver cytotoxic molecules to GSCs at the surgical tumor margins, the forefront of glioblastoma (GBM) recurrence, circumventing BBB hurdles. DOXO encapsulation proved in situ immune response activation within GBM microenvironment.

15.
Glycobiology ; 20(9): 1186-95, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20542873

RESUMO

A preparation of a membrane-bound trehalase from the larvae of the midge Chironomus riparius (Diptera: Chironomidae) was obtained by detergent solubilization, ion-exchange chromatography and concanavalin A affinity chromatography. Trehalase was purified 1080-fold to a specific activity of 75 U mg(-)(1). The initial rate of trehalase activity followed Henri-Michaelis-Menten kinetics with a K(m) of 0.48 +/- 0.04 mM. Catalytic efficiency was maximal at pH 6.5. The activity was highly inhibited by mono- and bicyclic iminosugar alkaloids such as (in order of potency) casuarine (IC(50) = 0.25 +/- 0.03 microM), deoxynojirimycin (IC(50) = 2.83 +/- 0.34 microM) and castanospermine (IC(50) = 12.7 +/- 1.4 microM). Increasing substrate concentration reduced the inhibition. However, in the presence of deoxynojirimycin, Lineweaver-Burk plots were curvilinear upward. Linear plots were obtained with porcine trehalase. Here, we propose that deoxynojirimycin inhibits the activity of trehalase from C. riparius according to a ligand exclusion model. Inhibition was further characterized by measuring enzyme activity in the presence of a series of casuarine and deoxynojirimycin derivatives. For comparison, inhibition studies were also performed with porcine trehalase. Results indicate substantial differences between midge trehalase and mammalian trehalase suggesting that, in principle, inhibitors against insect pests having trehalase as biochemical targets can be developed.


Assuntos
Chironomidae/enzimologia , Larva/enzimologia , Trealase/antagonistas & inibidores , Trealase/isolamento & purificação , Trealase/metabolismo , 1-Desoxinojirimicina/farmacologia , Alcaloides/farmacologia , Animais , Membrana Celular/química , Membrana Celular/metabolismo , Chironomidae/crescimento & desenvolvimento , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Glucosamina/análogos & derivados , Glucosamina/farmacologia , Glicosídeo Hidrolases/antagonistas & inibidores , Cinética , Larva/química , Proteínas de Membrana/isolamento & purificação , Proteínas de Membrana/metabolismo , Modelos Biológicos , Pirróis/farmacologia , Especificidade por Substrato/efeitos dos fármacos
16.
Eur Biophys J ; 39(12): 1613-23, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20694815

RESUMO

ß-Amyloid peptide (Aß) plays a key role in the pathogenesis of Alzheimer disease (AD). Monomeric Aß undergoes aggregation, forming oligomers and fibrils, resulting in the deposition of plaques in the brain of AD patients. A widely used protocol for fibril formation in vitro is based on incubation of the peptide at low pH and ionic strength, which generates Aß fibrils several microns long. What happens to such fibrils once they are brought to physiological pH and ionic strength for biological studies is not fully understood. In this investigation, we show that these changes strongly affect the morphology of fibrils, causing their fragmentation into smaller ones followed by their aggregation into disordered structures. We show that an increase in pH is responsible for fibril fragmentation, while increased ionic strength is responsible for the aggregation of fibril fragments. This behavior was confirmed on different batches of peptide either produced by the same company or of different origin. Similar aggregates of short fibrils are obtained when monomeric peptide is incubated under physiological conditions of pH and ionic strength, suggesting that fibril morphology is independent of the fibrillation protocol but depends on the final chemical environment. This was also confirmed by experiments with cell cultures showing that the toxicity of fibrils with different initial morphology is the same after addition to the medium. This information is of fundamental importance when Aß fibrils are prepared in vitro at acidic pH and then diluted into physiological buffer for biological investigations.


Assuntos
Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/metabolismo , Amiloide/química , Amiloide/metabolismo , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Amiloide/ultraestrutura , Peptídeos beta-Amiloides/ultraestrutura , Humanos , Concentração de Íons de Hidrogênio , Microscopia de Força Atômica , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Concentração Osmolar , Fragmentos de Peptídeos/ultraestrutura , Estabilidade Proteica , Espalhamento de Radiação , Células Tumorais Cultivadas
17.
Mol Cell Neurosci ; 42(1): 75-80, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19520166

RESUMO

We show that in hippocampal cultured neurons, dephosphorylation of peptidyl-prolyl cis-trans isomerase Pin1 on Ser16 is occurring during the early stages of exposure to Abeta (1-42) oligomers. This occurrence, resulting in Pin1 activation, is paralleled by Tau(Thr231) dephosphorylation, probably due to Pin1-mediated Tau isomerisation. Indeed, in the presence of the specific Pin1 inhibitor juglone, Abeta-induced Tau(Thr231)dephosphorylation is prevented. The involvement of protein phosphatase 2A (PP2A) in dephosphorylation of isomerised Tau is shown by the co-treatment of neurons with Abeta (1-42) and okadaic acid, a PP2A inhibitor, leading to Tau(Thr231) hyperphosphorylation. We also report the modulation, via Pin1, of Ser199, Ser396, Ser400 and Ser404 phosphorylation state in response to Abeta treatment. Taken together, these data suggest for the first time that an early Pin1 response might be transiently evoked by Abeta 1-42 oligomers, preventing Tau hyperphosphorylation. This evidence highlights the role of Pin1 as Tau phosphorylation modulator during Alzheimer onset.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Peptídeos beta-Amiloides/farmacologia , Neurônios/metabolismo , Fragmentos de Peptídeos/farmacologia , Proteínas tau/metabolismo , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Citarabina/farmacologia , Embrião de Mamíferos , Inibidores Enzimáticos/farmacologia , Formazans , Hipocampo/citologia , Imunossupressores/farmacologia , Microscopia de Força Atômica/métodos , Naftoquinonas/farmacologia , Neurônios/efeitos dos fármacos , Ácido Okadáico/farmacologia , Fosforilação/efeitos dos fármacos , Fosforilação/fisiologia , Propanóis/farmacologia , Ratos , Sais de Tetrazólio , Fatores de Tempo
18.
PeerJ ; 6: e4554, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29593944

RESUMO

The evolution and occurrence of fossil sea turtles at the Pacific margin of South America is poorly known and restricted to Neogene (Miocene/Pliocene) findings from the Pisco Formation, Peru. Here we report and describe the first record of Oligocene (late Oligocene, ∼24 Ma) Pan-Cheloniidae sea turtle remains of South America. The fossil material corresponds to a single, isolated and well-preserved costal bone found at the Montañita/Olón locality, Santa Elena Province, Ecuador. Comparisons with other Oligocene and extant representatives allow us to confirm that belongs to a sea turtle characterized by: lack of lateral ossification, allowing the dorsal exposure of the distal end of ribs; dorsal surface of bone sculptured, changing from dense vermiculation at the vertebral scute region to anastomosing pattern of grooves at the most lateral portion of the costal. This fossil finding shows the high potential that the Ecuadorian Oligocene outcrops have in order to explore the evolution and paleobiogeography distribution of sea turtles by the time that the Pacific and the Atlantic oceans were connected via the Panama basin.

19.
Phytomedicine ; 42: 233-244, 2018 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-29655691

RESUMO

BACKGROUND: Multi-target drugs have gained significant recognition for the treatment of multifactorial diseases such as depression. Under a screening study of multi-potent medicinal plants with claimed antidepressant-like activity, the phenolic-rich Annona muricata aqueous extract (AE) emerged as a moderate monoamine oxidase A (hMAO-A) inhibitor and a strong hydrogen peroxide (H2O2) scavenger. PURPOSE: In order to protect this extract from gastrointestinal biotransformation and to improve its permeability across the blood-brain barrier (BBB), four phospholipid nanoformulations of liposomes and phytosomes functionalized with a peptide ligand promoting BBB crossing were produced. METHODS: AE and nanoformulations were characterized by HPLC-DAD-ESI-MSn, HPLC-DAD, spectrophotometric, fluorescence and dynamic light scattering methods. Cytotoxicity and permeability studies were carried out using an in vitro transwell model of the BBB, composed of immortalized human microvascular endothelial cells (hCMEC/D3), and in vitro hMAO-A inhibition and H2O2 scavenging activities were performed with all samples. RESULTS: The encapsulation/binding of AE was more efficient with phytosomes, while liposomes were more stable, displaying a slower extract release over time. In general, phytosomes were less toxic than liposomes in hCMEC/D3 cells and, when present, cholesterol improved the permeability across the cell monolayer of all tested nanoformulations. All nanoformulations conserved the antioxidant potential of AE, while phosphatidylcholine interfered with MAO-A inhibition assay. CONCLUSIONS: Overall, phytosome formulations registered the best performance in terms of binding efficiency, enzyme inhibition and scavenging activity, thus representing a promising multipotent phenolic-rich nanoshuttle for future in vivo depression treatment.


Assuntos
Annona/química , Antioxidantes/farmacologia , Portadores de Fármacos/química , Lipossomos/química , Extratos Vegetais/administração & dosagem , Barreira Hematoencefálica/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Portadores de Fármacos/administração & dosagem , Células Endoteliais/efeitos dos fármacos , Sequestradores de Radicais Livres/farmacologia , Humanos , Peróxido de Hidrogênio/metabolismo , Lipossomos/administração & dosagem , Inibidores da Monoaminoxidase/farmacologia , Nanoestruturas/administração & dosagem , Nanoestruturas/química , Fenóis/farmacologia , Extratos Vegetais/farmacologia , Espectrometria de Massas por Ionização por Electrospray
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