RESUMEN
MAIN CONCLUSION: A ß-ketoacyl-ACP-synthase II (KAS2) like enzyme and a lysophosphatidic acid acyltransferase (LPAT2) from Consolida ajacis catalyze gondoic acid biosynthesis and incorporation into the sn-2 position of seed TAG in engineered Camelina sativa. Gondoic acid (cis-11 eicosenoic acid, 20:1∆11) is the predominant very-long-chain fatty acid (VLCFA) in camelina (Camelina sativa) seed oil accounting for 12-15% of total triacylglycerol fatty acids. To explore the feasibility of engineering increased levels of this fatty acid in camelina seed, oils from a range of plant species were analyzed to identify those producing 20-Carbon (C20) fatty acids as the only VLCFAs in their seed oil. Seeds of Consolida and Delphinium species (Ranunculaceae) were found to contain moderate levels (0.2% to 25.5%) of C20 fatty acids without accompanying longer chain fatty acids. The C20 fatty acids were abundant in both sn-2 and sn-1/3 positions of seed TAG in Consolida, but were largely absent from the sn-2 position in Delphinium seed TAG. Through generation of a developing seed transcriptome, sequences were identified and cDNAs amplified from Consolida ajacis encoding a ß-ketoacyl-ACP-synthase II like protein (CaKAS2B) that lacked a predicted chloroplast transit peptide, and two homologues of Arabidopsis thaliana lysophosphatidic acid acyltransferase 2 (CaLPAT2a and CaLPAT2b). Expression of CaKAS2B in conventional (WT) camelina and a line previously engineered for high seed oleic acid content (HO) resulted in increased seed VLCFA content. Total VLCFA levels were raised from 24 to 35% and from 7 to 23% in T3 seed from representative transformants in the WT and HO backgrounds, respectively. Gondoic acid was the predominant VLCFA in transformed HO lines with low endogenous cytoplasmic fatty acid elongation activity, suggesting limited capacity of CaKAS2B to elongate beyond C20. Expression in camelina of CaLPAT2b resulted in significantly increased C20-VLCFA esterification at the sn-2 position of seed TAG with VLCFA levels of 33.8% in this position in one transformed line compared to 0.3% at sn-2 in the corresponding control line. Only small changes in total seed VLCFA content were observed in transformed lines implying that increased VLCFA esterification capacity in camelina results in positional redistribution of VLCFAs but does not significantly enhance flux through the fatty acid elongation pathway. The full potential of CaKAS2B and CaLPAT2a for the engineering of high gondoic acid levels in camelina remains to be determined. Seed fatty acid composition of Consolida and Delphinium also provides information that may be of value in the systematics of the Ranunculaceae.
Asunto(s)
Brassicaceae , Delphinium , Brassicaceae/genética , ADN Complementario/genética , Expresión Génica Ectópica , Ácidos Grasos , Ácidos Grasos Monoinsaturados , Aceites de Plantas , Plantas Modificadas Genéticamente , Semillas/genética , TriglicéridosRESUMEN
In order to avoid expensive clinical failures, better and more predictive animal models of vaccine efficacy are needed to screen Shigella and ETEC vaccine candidates for protective efficacy. The 2016 Vaccines Against Shigella and ETEC (VASE) Conference included a workshop focused on the strengths and weaknesses of current models, particularly in terms of the correlation to vaccine efficacy in human clinical trials. Workshop presenters shared information on existing preclinical animal models for assessing the immunogenicity and protective efficacy of Shigella and ETEC vaccines. The presentations were followed by a discussion about how to best utilize these models, how the models can be improved, and best practices for Shigella and ETEC vaccine developers. The workshop concluded with three major recommendations for the field: (1) develop better and more consistent reagents for animal studies and make them widely available, (2) prioritize harmonization of animal models and immunology assays, and (3) develop preclinical correlates of protection, which will be key in selecting the best vaccine candidates for further clinical development.
Asunto(s)
Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Resultado del Tratamiento , Animales , Disentería Bacilar/microbiología , Disentería Bacilar/prevención & control , Escherichia coli Enterotoxigénica/inmunología , Infecciones por Escherichia coli/microbiología , Infecciones por Escherichia coli/prevención & control , Vacunas contra Escherichia coli/administración & dosificación , Humanos , Reproducibilidad de los Resultados , Shigella/inmunología , Vacunas contra la Shigella/administración & dosificaciónRESUMEN
Feedstocks for industrial applications ranging from polymers to lubricants are largely derived from petroleum, a non-renewable resource. Vegetable oils with fatty acid structures and storage forms tailored for specific industrial uses offer renewable and potentially sustainable sources of petrochemical-type functionalities. A wide array of industrial vegetable oils can be generated through biotechnology, but will likely require non-commodity oilseed platforms dedicated to specialty oil production for commercial acceptance. Here we show the feasibility of three Brassicaceae oilseeds crambe, camelina, and carinata, none of which are widely cultivated for food use, as hosts for complex metabolic engineering of wax esters for lubricant applications. Lines producing wax esters >20% of total seed oil were generated for each crop and further improved for high temperature oxidative stability by down-regulation of fatty acid polyunsaturation. Field cultivation of optimized wax ester-producing crambe demonstrated commercial utility of these engineered crops and a path for sustainable production of other industrial oils in dedicated specialty oilseeds.
Asunto(s)
Reactores Biológicos , Brassicaceae/metabolismo , Productos Agrícolas/metabolismo , Ingeniería Metabólica , Aceites de Plantas/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Ceras/metabolismo , Brassicaceae/genética , Productos Agrícolas/genética , Plantas Modificadas Genéticamente/genéticaRESUMEN
OBJECTIVE: To investigate the chemical constituents in the ethanol extract from the whole plant of Euphorbia lunulata. METHODS: The whole plant of Euphorbia lunulata was extracted by 95% ethanol, then partitioned by system solvents with different polarity. The ethyl acetate and n-butyl alcohol extracts were separated on silica gel, Sephadex LH-20,and MCI columns. The isolated compounds were determined by detailed analysis of their spectral data. RESULTS: Twelve compounds were isolated and identified from the ethyl acetate and n-butyl alcohol extracts of Euphorbia lunulata and the structures were identified as 7ß-methoxy-stigmast-5-ene-3ß-ol (1), 7ß-methoxy-stigmast-5-ene-3ß,22ß-diol(2), asperglaucide(3), moscatin (4), p-hydroxybenzoic acid (5),3-methoxy-4-hydroxy benzoic acid(6), erigeside C(7),5,7,4'-trihydroxy flavanone(8), kaempferol(9), quercetin(10), corosolic acid(11) and acacetin (12). CONCLUSION: All compounds except for 9 and 10 are reported from this plant for the first time.
Asunto(s)
Euphorbia/química , Fitoquímicos/química , Extractos Vegetales/química , Quempferoles , Fitoquímicos/aislamiento & purificación , QuercetinaRESUMEN
Triacylglycerol estolides have been reported as components of the seed oil of a number of plant species and are generally associated with the presence of fatty acids containing hydroxyl groups. We have used MALDI-TOF MS to examine the intact acylglycerol species present in the seed oils of two plants that produce kamlolenic acid (18-hydroxy-Δ9cis,11trans,13trans-octadecatrienoic acid). Mallotus philippensis and Trewia nudiflora were both shown to produce seed oil rich in TAG-estolides. Analysis by MALDI-TOF MS/MS demonstrated that the TAG-estolides had a structure different to that previously proposed after enzymatic digestion of the oil. Acylglycerols containing up to 14 fatty acids were detected but fatty acid estolides were only present in a single position on the glycerol backbone, with predominantly non-hydroxyl fatty acids in the remaining two positions. Increased numbers of fatty acids per glycerol backbone were accounted for by the presence of fatty acid estolides containing a correspondingly greater number of fatty acids. For example, acylglycerols containing seven fatty acids had a fatty acid estolide of five fatty acids at one position on the glycerol backbone. Both capped and uncapped fatty acid estolides, with a free hydroxyl group, were present, with capped fatty acid estolides being more abundant in T. nudiflora and uncapped fatty acid estolides in M. philippensis.
Asunto(s)
Euphorbiaceae/química , Mallotus (Planta)/química , Aceites de Plantas/química , Semillas/química , Triglicéridos/análisis , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
The pathological lesions typical of Alzheimer disease (AD) are sites of significant and abnormal metal accumulation. Metal chelation therapy, therefore, provides a very attractive therapeutic measure for the neuronal deterioration of AD, though its institution suffers fundamental deficiencies. Namely, chelating agents, which bind to and remove excess transition metals from the body, must penetrate the blood-brain barrier to instill any real effect on the oxidative damages caused by the presence of the metals in the brain. Despite many advances in chelation administration, however, this vital requirement remains therapeutically out of reach: the most effective chelators-i.e., those that have high affinity and specificity for transition metals like iron and copper-are bulky and hydrophilic, making it difficult to reach their physiological place of action. Moreover, small, lipophilic chelators, which can pass through the brain's defensive wall, essentially suffer from their over-effectiveness. That is, they induce toxicity on proliferating cells by removing transition metals from vital RNA enzymes. Fortunately, research has provided a loophole. Nanoparticles, tiny, artificial or natural organic polymers, are capable of transporting metal chelating agents across the blood-brain barrier regardless of their size and hydrophilicity. The compounds can thereby sufficiently ameliorate the oxidative toxicity of excess metals in an AD brain without inducing any such toxicity themselves. We here discuss the current status of nanoparticle delivery systems as they relate to AD chelation therapy and elaborate on their mechanism of action. An exciting future for AD treatment lies ahead.
Asunto(s)
Encéfalo/efectos de los fármacos , Quelantes/administración & dosificación , Terapia por Quelación , Sistemas de Liberación de Medicamentos , Nanopartículas/química , Estrés Oxidativo/efectos de los fármacos , Elementos de Transición , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Animales , Barrera Hematoencefálica/efectos de los fármacos , Barrera Hematoencefálica/metabolismo , Quelantes/farmacocinética , Humanos , Permeabilidad/efectos de los fármacos , Receptores de LDL/metabolismoRESUMEN
Recent studies have implicated resveratrol and pterostilbene, a resveratrol derivative, in the protection against age-related diseases including Alzheimer's disease (AD). However, the mechanism for the favorable effects of resveratrol in the brain remains unclear and information about direct cross-comparisons between these analogs is rare. As such, the purpose of this study was to compare the effectiveness of diet-achievable supplementation of resveratrol to that of pterostilbene at improving functional deficits and AD pathology in the SAMP8 mouse, a model of accelerated aging that is increasingly being validated as a model of sporadic and age-related AD. Furthermore we sought to determine the mechanism of action responsible for functional improvements observed by studying cellular stress, inflammation, and pathology markers known to be altered in AD. Two months of pterostilbene diet but not resveratrol significantly improved radial arm water maze function in SAMP8 compared with control-fed animals. Neither resveratrol nor pterostilbene increased sirtuin 1 (SIRT1) expression or downstream markers of sirtuin 1 activation. Importantly, markers of cellular stress, inflammation, and AD pathology were positively modulated by pterostilbene but not resveratrol and were associated with upregulation of peroxisome proliferator-activated receptor (PPAR) alpha expression. Taken together our findings indicate that at equivalent and diet-achievable doses pterostilbene is a more potent modulator of cognition and cellular stress than resveratrol, likely driven by increased peroxisome proliferator-activated receptor alpha expression and increased lipophilicity due to substitution of hydroxy with methoxy group in pterostilbene.
Asunto(s)
Envejecimiento/efectos de los fármacos , Enfermedad de Alzheimer/tratamiento farmacológico , Neurotransmisores/administración & dosificación , Estilbenos/administración & dosificación , Envejecimiento/sangre , Envejecimiento/genética , Enfermedad de Alzheimer/genética , Análisis de Varianza , Animales , Disponibilidad Biológica , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Suplementos Dietéticos , Modelos Animales de Enfermedad , Femenino , Cromatografía de Gases y Espectrometría de Masas , Regulación de la Expresión Génica/efectos de los fármacos , MAP Quinasa Quinasa 4/metabolismo , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Ratones , Neurotransmisores/sangre , PPAR alfa/metabolismo , Fosforilación/efectos de los fármacos , Proteínas Serina-Treonina Quinasas/metabolismo , Resveratrol , Transducción de Señal/efectos de los fármacos , Sirtuina 1/genética , Sirtuina 1/metabolismo , Estilbenos/sangre , Proteínas tau/metabolismo , Quinasa de Factor Nuclear kappa BRESUMEN
Oxidative stress is an important factor, and one that acts in the earliest stages, of Alzheimer's disease (AD) pathogenesis. The reduction of oxidative stress has been tested as a therapy for AD. While the trial of vitamin E supplementation in moderately severe AD is the most promising so far, it also reveals the limitations of general antioxidant therapies that simply lower oxidative stress and, therefore, the complexity of the redox system. The multiple contributing factors that foster the clinical manifestations of AD should be considered when designing antioxidative stress therapy. In this article, we discuss the multiple pathogenic mechanisms of oxidative stress in AD and the potential targeting approaches.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Antioxidantes/uso terapéutico , Estrés Oxidativo/fisiología , Enfermedad de Alzheimer/fisiopatología , Animales , Ensayos Clínicos como Asunto , Humanos , Estrés Oxidativo/efectos de los fármacosRESUMEN
Current therapies for Alzheimer disease (AD) such as the acetylcholinesterase inhibitors and the latest NMDA receptor inhibitor, Namenda, provide moderate symptomatic delay at various stages of the disease, but do not arrest the disease progression or bring in meaningful remission. New approaches to the disease management are urgently needed. Although the etiology of AD is largely unknown, oxidative damage mediated by metals is likely a significant contributor since metals such as iron, aluminum, zinc, and copper are dysregulated and/or increased in AD brain tissue and create a pro-oxidative environment. This role of metal ion-induced free radical formation in AD makes chelation therapy an attractive means of dampening the oxidative stress burden in neurons. The chelator desferrioxamine, FDA approved for iron overload, has shown some benefit in AD, but like many chelators, it has a host of adverse effects and substantial obstacles for tissue-specific targeting. Other chelators are under development and have shown various strengths and weaknesses. Here, we propose a novel system of chelation therapy through the use of nanoparticles. Nanoparticles conjugated to chelators show unique ability to cross the blood-brain barrier (BBB), chelate metals, and exit through the BBB with their corresponding complexed metal ions. This method may provide a safer and more effective means of reducing the metal load in neural tissue, thus attenuating the harmful effects of oxidative damage and its sequelae. Experimental procedures are presented in this chapter.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Terapia por Quelación/métodos , Quelantes del Hierro/uso terapéutico , Nanopartículas , Anciano , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Benzoatos/química , Benzoatos/farmacología , Benzoatos/uso terapéutico , Barrera Hematoencefálica/metabolismo , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Deferasirox , Deferoxamina/química , Deferoxamina/farmacología , Deferoxamina/uso terapéutico , Portadores de Fármacos/síntesis química , Portadores de Fármacos/química , Portadores de Fármacos/farmacología , Portadores de Fármacos/uso terapéutico , Ferritinas/química , Humanos , Hierro/química , Quelantes del Hierro/síntesis química , Quelantes del Hierro/química , Quelantes del Hierro/farmacología , Metales/química , Metales/metabolismo , Estructura Molecular , Nanopartículas/química , Nanopartículas/uso terapéutico , Triazoles/química , Triazoles/farmacología , Triazoles/uso terapéuticoAsunto(s)
Enfermedad de Alzheimer/etiología , Memantina/farmacología , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Amiloide/efectos de los fármacos , Amiloide/metabolismo , Animales , Antiparkinsonianos/farmacología , Antiparkinsonianos/uso terapéutico , Ensayos Clínicos como Asunto , Formación de Concepto/fisiología , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Humanos , Memantina/uso terapéutico , Ratones , Ratones Transgénicos , Especificidad de la EspecieRESUMEN
Brain function declines with age and is associated with diminishing mitochondrial integrity. The neuronal mitochondrial ultrastructural changes of young (4 months) and old (21 months) F344 rats supplemented with two mitochondrial metabolites, acetyl-L-carnitine (ALCAR, 0.2%[wt/vol] in the drinking water) and R-alpha-lipoic acid (LA, 0.1%[wt/wt] in the chow), were analysed using qualitative and quantitative electron microscopy techniques. Two independent morphologists blinded to sample identity examined and scored all electron micrographs. Mitochondria were examined in each micrograph, and each structure was scored according to the degree of injury. Controls displayed an age-associated significant decrease in the number of intact mitochondria (P = 0.026) as well as an increase in mitochondria with broken cristae (P < 0.001) in the hippocampus as demonstrated by electron microscopic observations. Neuronal mitochondrial damage was associated with damage in vessel wall cells, especially vascular endothelial cells. Dietary supplementation of young and aged animals increased the proliferation of intact mitochondria and reduced the density of mitochondria associated with vacuoles and lipofuscin. Feeding old rats ALCAR and LA significantly reduced the number of severely damaged mitochondria (P = 0.02) and increased the number of intact mitochondria (P < 0.001) in the hippocampus. These results suggest that feeding ALCAR with LA may ameliorate age-associated mitochondrial ultrastructural decay and are consistent with previous studies showing improved brain function.
Asunto(s)
Acetilcarnitina/farmacología , Envejecimiento/fisiología , Mitocondrias , Neuronas , Ácido Tióctico/farmacología , Acetilcarnitina/administración & dosificación , Animales , Suplementos Dietéticos , Hipocampo/citología , Masculino , Mitocondrias/efectos de los fármacos , Mitocondrias/patología , Mitocondrias/ultraestructura , Neuronas/efectos de los fármacos , Neuronas/ultraestructura , Distribución Aleatoria , Ratas , Ratas Endogámicas F344 , Ácido Tióctico/administración & dosificaciónRESUMEN
Ebola virus (EBOV) is a significant human pathogen that presents a public health concern as an emerging/re-emerging virus and as a potential biological weapon. Substantial progress has been made over the last decade in developing candidate preventive vaccines that can protect nonhuman primates against EBOV. Among these prospects, a vaccine based on recombinant vesicular stomatitis virus (VSV) is particularly robust, as it can also confer protection when administered as a postexposure treatment. A concern that has been raised regarding the replication-competent VSV vectors that express EBOV glycoproteins is how these vectors would be tolerated by individuals with altered or compromised immune systems such as patients infected with HIV. This is especially important as all EBOV outbreaks to date have occurred in areas of Central and Western Africa with high HIV incidence rates in the population. In order to address this concern, we evaluated the safety of the recombinant VSV vector expressing the Zaire ebolavirus glycoprotein (VSVDeltaG/ZEBOVGP) in six rhesus macaques infected with simian-human immunodeficiency virus (SHIV). All six animals showed no evidence of illness associated with the VSVDeltaG/ZEBOVGP vaccine, suggesting that this vaccine may be safe in immunocompromised populations. While one goal of the study was to evaluate the safety of the candidate vaccine platform, it was also of interest to determine if altered immune status would affect vaccine efficacy. The vaccine protected 4 of 6 SHIV-infected macaques from death following ZEBOV challenge. Evaluation of CD4+ T cells in all animals showed that the animals that succumbed to lethal ZEBOV challenge had the lowest CD4+ counts, suggesting that CD4+ T cells may play a role in mediating protection against ZEBOV.
Asunto(s)
Vacunas contra el Virus del Ébola/farmacología , Huésped Inmunocomprometido , Estomatitis Vesicular , Animales , Linfocitos T CD4-Positivos , Evaluación Preclínica de Medicamentos , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Vacunas contra el Virus del Ébola/administración & dosificación , Vectores Genéticos , Macaca mulatta , Primates , Síndrome de Inmunodeficiencia Adquirida del Simio/terapia , Resultado del Tratamiento , Proteínas ViralesRESUMEN
In this study, we evaluated the effect of lipoic acid (LA) and N-acetyl cysteine (NAC) on oxidative [4-hydroxy-2-nonenal, N(epsilon)-(carboxymethyl)lysine and heme oxygenase-1] and apoptotic (caspase 9 and Bax) markers in fibroblasts from patients with Alzheimer disease (AD) and age-matched and young controls. AD fibroblasts showed the highest levels of oxidative stress, and the antioxidants, lipoic acid (1 mM) and/or N-acetyl cysteine (100 microM) exerted a protective effect as evidenced by decreases in oxidative stress and apoptotic markers. Furthermore, we observed that the protective effect of LA and NAC was more pronounced when both agents were present simultaneously. AD-type changes could be generated in control fibroblasts using N-methylprotoporphyrin to inhibit cytochrome oxidase assembly indicating that the the oxidative damage observed was associated with mitochondrial dysfunction. The effects of N-methylprotoporphyrine were reversed or attenuated by both lipoic acid and N-acetyl cysteine. These data suggest mitochondria are important in oxidative damage that occurs in AD. As such, antioxidant therapies based on lipoic acid and N-acetyl cysteine supplementation may be promising.
Asunto(s)
Acetilcisteína/farmacología , Enfermedad de Alzheimer/tratamiento farmacológico , Fibroblastos/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Ácido Tióctico/farmacología , Acetilcisteína/administración & dosificación , Humanos , Inmunohistoquímica , Ácido Tióctico/administración & dosificaciónRESUMEN
Trichosanthin (TCS), a traditional Chinese medicine, exerts antitumor activities by inducing apoptosis in many different tumor cell lines. However, the mechanisms remain obscure. The present study focused on various caspase pathways that may be involved in TCS-induced apoptosis in leukemia HL-60 cells. Key caspases in both intrinsic and extrinsic pathways including caspase-8, -9 and -3 were activated upon TCS treatment. Additionally, TCS treatment induced upregulation of BiP and CHOP and also activated caspase-4, which for the first time strongly supported the involvement of endoplasmic reticulum stress pathway in TCS-induced apoptosis. Interestingly, although caspase-8 was activated, Fas/Fas ligand pathway was not involved as evidenced by a lack of induction of Fas or Fas ligand and a lack of inhibitory effect of anti-Fas blocking antibody on TCS-induced apoptosis. Instead, caspase-8 was activated in a caspase-9 and -4 dependent manner. The involvement of mitochondria was demonstrated by the reduction of mitochondrial membrane potential and release of cytochrome c and Smac besides the activation of caspase-9. Further investigation confirmed that caspase-3 was the major executioner caspase downstream to caspase-9, -4 and -8. Taken together, our results suggested that TCS-induced apoptosis in HL-60 cells was mainly mediated by mitochondrial and ER stress signaling pathways via caspase-3.
Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Apoptosis/efectos de los fármacos , Retículo Endoplásmico/metabolismo , Mitocondrias/metabolismo , Transducción de Señal , Tricosantina/farmacología , Caspasa 3/metabolismo , Caspasa 8/metabolismo , Caspasa 9/metabolismo , Caspasas Iniciadoras , Relación Dosis-Respuesta a Droga , Chaperón BiP del Retículo Endoplásmico , Activación Enzimática/efectos de los fármacos , Células HL-60 , Proteínas de Choque Térmico/metabolismo , Humanos , Potenciales de la Membrana/efectos de los fármacos , Modelos Biológicos , Chaperonas Moleculares/metabolismo , Transducción de Señal/efectos de los fármacos , Factores de Tiempo , Factor de Transcripción CHOP/metabolismoRESUMEN
Accumulating evidence suggests that oxidative stress may be a major etiologic factor in initiating and promoting neurodegeneration in Alzheimer disease. Contributing to this, there is a dyshomeostasis of metal ions in Alzheimer disease with abnormally high levels of redox-active metals, particularly iron, in affected areas of the brain. Although it is unclear whether metal excesses are the sole cause of oxidative stress and neurodegeneration or a by-product of neuronal loss, the finding that metal chelators can partially solubilize amyloid-beta deposits in Alzheimer disease suggests a promising therapeutic role for chelating agents. However, the blood-brain barrier and toxicity of known chelators limit their utility. In this study, we suggest that covalent conjugation of iron chelators with nanoparticles may help overcome the limitations in blood-brain barrier permeability of existing chelation therapy. Using in vitro studies, we have shown that a chelator-nanoparticle system and the chelator-nanoparticle system complexed with iron, when incubated with human plasma, preferentially adsorb apolipoprotein E and apolipoprotein A-I, that would facilitate transport into and out of the brain via mechanisms used for transporting low-density lipoprotein. Our studies suggest a unique approach, utilizing nanoparticles, to transport chelators and chelator-metal complexes in both directions across the blood-brain barrier, thus providing safer and more effective chelation treatment in Alzheimer disease and other neurodegenerative diseases.
Asunto(s)
Enfermedad de Alzheimer/patología , Encéfalo/efectos de los fármacos , Quelantes del Hierro/farmacología , Hierro/metabolismo , Nanoestructuras , Piridonas/farmacología , Anciano de 80 o más Años , Apolipoproteína A-I/metabolismo , Apolipoproteínas E/metabolismo , Electroforesis en Gel Bidimensional/métodos , Humanos , Técnicas In Vitro , Quelantes del Hierro/química , Piridonas/químicaRESUMEN
Current therapies for Alzheimer disease (AD) such as the anticholinesterase inhibitors and the latest NMDA receptor inhibitor, Namenda, provide moderate symptomatic delay at various stages of disease, but do not arrest disease progression or supply meaningful remission. As such, new approaches to disease management are urgently needed. Although the etiology of AD is largely unknown, oxidative damage mediated by metals is likely a significant contributor since metals such as iron, aluminum, zinc, and copper are dysregulated and/or increased in AD brain tissue and create a pro-oxidative environment. This role of metal ion-induced free radical formation in AD makes chelation therapy an attractive means of dampening the oxidative stress burden in neurons. The chelator desferioxamine, FDA approved for iron overload, has shown some benefit in AD, but like many chelators, it has a host of adverse effects and substantial obstacles for tissue-specific targeting. Other chelators are under development and have shown various strengths and weaknesses. In this review, we propose a novel system of chelation therapy through the use of nanoparticles. Nanoparticles conjugated to chelators show a unique ability to cross the blood-brain barrier (BBB), chelate metals, and exit through the BBB with their corresponding complexed metal ions. This method may prove to be a safe and effective means of reducing the metal load in neural tissue thus staving off the harmful effects of oxidative damage and its sequelae.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Quelantes/uso terapéutico , Terapia por Quelación/métodos , Nanoestructuras , Barrera Hematoencefálica/metabolismo , Quelantes/metabolismo , Humanos , PermeabilidadRESUMEN
We tested the hypothesis that green tea prevents diabetes-related tissue dysfunctions attributable to oxidation. Diabetic rats were treated daily with tap water, vitamins C and E, or fresh Japanese green tea extract. After 12 months, body weights were decreased, whereas glycated lysine in aorta, tendon, and plasma were increased by diabetes (P < 0.001) but unaffected by treatment. Erythrocyte glutathione and plasma hydroperoxides were improved by the vitamins (P < 0.05) and green tea (P < 0.001). Retinal superoxide production, acellular capillaries, and pericyte ghosts were increased by diabetes (P < 0.001) and improved by green tea and the vitamins (P variable). Lens crystallin fluorescence at 370/440 nm was ameliorated by green tea (P < 0.05) but not the vitamins. Marginal effects on nephropathy parameters were noted. However, suppressed renal mitochondrial NADH-linked ADP-dependent and dinitrophenol-dependent respiration and complex III activity were improved by green tea (P variable). Green tea also suppressed the methylglyoxal hydroimidazolone immunostaining of a 28-kDa mitochondrial protein. Surprising, glycoxidation in tendon, aorta, and plasma was either worsened or not significantly improved by the vitamins and green tea. Glucosepane cross-links were increased by diabetes (P < 0.001), and green tea worsened total cross-linking. In conclusion, green tea and antioxidant vitamins improved several diabetes-related cellular dysfunctions but worsened matrix glycoxidation in selected tissues, suggesting that antioxidant treatment tilts the balance from oxidative to carbonyl stress in the extracellular compartment.
Asunto(s)
Antioxidantes/uso terapéutico , Ácido Ascórbico/uso terapéutico , Camellia sinensis , Colágeno/metabolismo , Diabetes Mellitus Experimental/fisiopatología , Nefropatías Diabéticas/patología , Retinopatía Diabética/tratamiento farmacológico , Fitoterapia , Té , Vitamina E/uso terapéutico , Animales , Glucemia/metabolismo , Peso Corporal , Colágeno/química , Colágeno/efectos de los fármacos , Reactivos de Enlaces Cruzados , Diabetes Mellitus Experimental/patología , Conducta Alimentaria/efectos de los fármacos , Productos Finales de Glicación Avanzada/metabolismo , Técnicas In Vitro , Masculino , Mitocondrias/patología , Consumo de Oxígeno/efectos de los fármacos , Ratas , Ratas Endogámicas LewRESUMEN
The rolling blackout (rbo) gene encodes an integral plasma membrane lipase required for Drosophila phototransduction. Photoreceptors are enriched for the RBO protein, and temperature-sensitive rbo mutants show reversible elimination of phototransduction within minutes, demonstrating an acute requirement for the protein. The block is activity dependent, indicating that the action of RBO is use dependent. Conditional rbo mutants show activity-dependent depletion of diacylglycerol and concomitant accumulation of phosphatidylinositol phosphate and phosphatidylinositol 4,5-bisphosphate within minutes of induction, suggesting rapid downregulation of phospholipase C (PLC) activity. The RBO requirement identifies an essential regulatory step in G-protein-coupled, PLC-dependent inositol lipid signaling mediating activation of TRP and TRPL channels during phototransduction.