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2.
Artículo en Inglés | MEDLINE | ID: mdl-31057649

RESUMEN

Alzheimer's disease (AD) is linked to an extensive neuron loss via accumulation of amyloid-beta (Aß) as senile plaques associated with reactive astrocytes and microglial activation in the brain. The objective of this study was to assess the therapeutic effect of WS-5 ethanol extract in vitro and in vivo against Aß-induced AD in mice and to identify the extract's active constituents. In the present study, WS-5 exerted a significant inhibitory effect on acetylcholinesterase (AChE). Analysis by transmission electron microscopy (TEM) revealed that WS-5 prevented Aß oligomerization via inhibition of Aß 1-42 aggregation. Evaluation of antioxidant activities using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) demonstrated that WS-5 possessed a high antioxidant activity, which was confirmed by measuring the total antioxidant status (TAS). Furthermore, the anti-inflammatory properties of WS-5 were examined using lipopolysaccharide-stimulated BV-2 microglial cells. WS-5 significantly inhibited the lipopolysaccharide-induced production of nitric oxide and two proinflammatory cytokines, TNF-α and IL-6. The memory impairment in mice with Aß-induced AD was studied using the Morris water maze and passive avoidance test. Immunohistochemistry was performed to monitor pathological changes in the hippocampus and cortex region of the mouse brain. The animal study showed that WS-5 (250 mg/kg) treatment improved learning and suppressed memory impairment as well as reduced Aß plaque accumulation in Aß-induced AD. HPLC analysis identified the extract's active compounds that exert anti-AChE activity. In summary, our findings suggest that WS-5 could be applied as a natural product therapy with a focus on neuroinflammation-related neurodegenerative disorders.

3.
Exp Mol Med ; 51(2): 1-18, 2019 02 12.
Artículo en Inglés | MEDLINE | ID: mdl-30755593

RESUMEN

We extracted 15 pterosin derivatives from Pteridium aquilinum that inhibited ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) and cholinesterases involved in the pathogenesis of Alzheimer's disease (AD). (2R)-Pterosin B inhibited BACE1, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with an IC50 of 29.6, 16.2 and 48.1 µM, respectively. The Ki values and binding energies (kcal/mol) between pterosins and BACE1, AChE, and BChE corresponded to the respective IC50 values. (2R)-Pterosin B was a noncompetitive inhibitor against human BACE1 and BChE as well as a mixed-type inhibitor against AChE, binding to the active sites of the corresponding enzymes. Molecular docking simulation of mixed-type and noncompetitive inhibitors for BACE1, AChE, and BChE indicated novel binding site-directed inhibition of the enzymes by pterosins and the structure-activity relationship. (2R)-Pterosin B exhibited a strong BBB permeability with an effective permeability (Pe) of 60.3×10-6 cm/s on PAMPA-BBB. (2R)-Pterosin B and (2R,3 R)-pteroside C significantly decreased the secretion of Aß peptides from neuroblastoma cells that overexpressed human ß-amyloid precursor protein at 500 µM. Conclusively, our study suggested that several pterosins are potential scaffolds for multitarget-directed ligands (MTDLs) for AD therapeutics.


Asunto(s)
Acetilcolinesterasa/química , Acetilcolinesterasa/metabolismo , Secretasas de la Proteína Precursora del Amiloide/química , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Ácido Aspártico Endopeptidasas/química , Ácido Aspártico Endopeptidasas/metabolismo , Barrera Hematoencefálica/metabolismo , Butirilcolinesterasa/química , Butirilcolinesterasa/metabolismo , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Animales , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Inhibidores de la Colinesterasa/química , Inhibidores de la Colinesterasa/farmacología , Relación Dosis-Respuesta a Droga , Activación Enzimática , Humanos , Ligandos , Ratones , Conformación Molecular , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Permeabilidad , Proteínas Recombinantes , Relación Estructura-Actividad
4.
Biomol Ther (Seoul) ; 26(6): 568-575, 2018 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-29534560

RESUMEN

In order to discover lifespan-extending compounds made from natural resources, activity-guided fractionation of Zingiber officinale Roscoe (Zingiberaceae) ethanol extract was performed using the Caenorhabditis elegans (C. elegans) model system. The compound 6-gingerol was isolated from the most active ethyl acetate soluble fraction, and showed potent longevity-promoting activity. It also elevated the survival rate of worms against stressful environment including thermal, osmotic, and oxidative conditions. Additionally, 6-gingerol elevated the antioxidant enzyme activities of C. elegans, and showed a dose-depend reduction of intracellular reactive oxygen species (ROS) accumulation in worms. Further studies demonstrated that the increased stress tolerance of 6-gingerol-mediated worms could result from the promotion of stress resistance proteins such as heat shock protein (HSP-16.2) and superoxide dismutase (SOD-3). The lipofuscin levels in 6-gingerol treated intestinal worms were decreased in comparison to the control group. No significant 6-gingerol-related changes, including growth, food intake, reproduction, and movement were noted. These results suggest that 6-gingerol exerted longevity-promoting activities independently of these factors and could extend the human lifespan.

5.
J Alzheimers Dis ; 29(3): 659-76, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22297647

RESUMEN

Neuroinflammation is implicated for amyloidogenesis. Sulfur compounds extracted from garlic have been shown to have anti-inflammatory properties. Previously, we have investigated that thiacremonone, a sulfur compound isolated from garlic has anti-inflammatory effects. To investigate thiacremonone's potential effect on anti-neuroinflammation and anti-amyloidogenesis, 4 week old ICR mice were given different doses of thiacremonone (1, 3, and 10 mg/kg) in drinking water for 1 month and received intraperitoneal injection of lipopolysaccharide (LPS) (250 µg/kg/day) at last 7 days of treatment. Our data show thiacremonone decreased LPS-induced memory impairment, glial activation, pro-inflammatory mediators' expression, and amyloidogenesis. In an in vitro study, we obtained similar results, with thiacremonone (1, 2, and 5 µg/ml) effectively decreased LPS (1 µg/ml)-induced glial activation and inflammatory mediators generation which are implicated in amyloidogenesis. Our data also demonstrated that thiacremonone inhibited LPS-induced amyloidogenesis in cultured astrocytes and microglial BV-2 cells. NF-κB, a critical transcriptional factor regulating not only inflammation but also amyloid-ß generation, was inhibited by thiacremonone via blocking of phosphorylation of IκBα in mice brain as well as cultured astrocytes and microglial BV-2 cells. These results indicated that the anti-inflammatory compound, thiacremonone, inhibited neuroinflammation and amyloidogenesis through inhibition of NF-κB activity, and thus could be applied for intervention of inflammation-related neurodegenerative disease including Alzheimer's disease.


Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/metabolismo , Péptidos beta-Amiloides/metabolismo , Antiinflamatorios/administración & dosificación , Encéfalo/metabolismo , Inflamación/prevención & control , Fragmentos de Péptidos/metabolismo , Tiofenos/administración & dosificación , Análisis de Varianza , Animales , Animales Recién Nacidos , Antiinflamatorios/química , Antiinflamatorios/farmacología , Astrocitos/efectos de los fármacos , Reacción de Prevención/efectos de los fármacos , Encéfalo/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Corteza Cerebral/citología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Ensayo de Cambio de Movilidad Electroforética , Conducta Exploratoria/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Inflamación/inducido químicamente , Inflamación/patología , Lipopolisacáridos/toxicidad , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Trastornos de la Memoria/inducido químicamente , Trastornos de la Memoria/prevención & control , Ratones , Ratones Endogámicos ICR , Óxido Nítrico/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Tiofenos/química , Tiofenos/farmacología
6.
Biochem Biophys Res Commun ; 408(4): 602-8, 2011 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-21530492

RESUMEN

Alzheimer's disease (AD), which is characterized by progressive cognitive impairment, is the most common neurodegenerative disease. Here, we investigated the preventive effect of a phosphodiesterase III inhibitor, cilostazol against cognitive decline in AD mouse model. In vitro studies using N2a cells stably expressing human amyloid precursor protein Swedish mutation (N2aSwe) showed that cilostazol decreased the amyloid ß (Aß) levels in the conditioned medium and cell lysates. Cilostazol attenuated the expression of ApoE, which is responsible for Aß aggregation, in N2aSwe. Intracerebroventricular injection of Aß(25-35) in C57BL/6J mice resulted in increased immunoreactivity of Aß and p-Tau, and microglia activation in the brain. Oral administration of cilostazol for 2 weeks before Aß administration and once a day for 4 weeks post-surgery almost completely prevented the Aß-induced increases of Aß and p-Tau immunoreactivity, as well as CD11b immunoreactivity. However, post-treatment with cilostazol 4 weeks after Aß administration, when Aß was already accumulated, did not prevent the Aß-induced neuropathological responses. Furthermore, cilostazol did not affect the neprilysin and insulin degrading enzymes involved in the degradation of the Aß peptide, but decreased ApoE levels in Aß-injected brain. In addition, cilostazol significantly improved spatial learning and memory in Aß-injected mice. The findings suggest that a phosphodiesterase III inhibitor, cilostazol significantly decreased Aß accumulation and improved memory impairment induced by Aß(25-35). The beneficial effects of cilostazol might be explained by the reduction of Aß accumulation and tau phosphorylation, not through an increase in Aß degradation but via a significant decrease in ApoE-mediated Aß aggregation. Cilostazol may be the basis of a novel strategy for the therapy of AD.


Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Péptidos beta-Amiloides/metabolismo , Trastornos del Conocimiento/tratamiento farmacológico , Inhibidores de Fosfodiesterasa 3/uso terapéutico , Tetrazoles/uso terapéutico , Enfermedad de Alzheimer/complicaciones , Péptidos beta-Amiloides/genética , Péptidos beta-Amiloides/farmacología , Animales , Línea Celular Tumoral , Cilostazol , Trastornos del Conocimiento/inducido químicamente , Trastornos del Conocimiento/etiología , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Fragmentos de Péptidos/farmacología , Fosforilación , Conducta Espacial , Proteínas tau/metabolismo
7.
J Biol Chem ; 284(3): 1373-84, 2009 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-19028695

RESUMEN

Proteolytic processing of amyloid precursor protein (APP) by beta- and gamma-secretases generates beta-amyloid (Abeta) peptides, which accumulate in the brains of individuals affected by Alzheimer disease. Detergent-resistant membrane microdomains (DRM) rich in cholesterol and sphingolipid, termed lipid rafts, have been implicated in Abeta production. Previously, we and others reported that the four integral subunits of the gamma-secretase associate with DRM. In this study we investigated the mechanisms underlying DRM association of gamma-secretase subunits. We report that in cultured cells and in brain the gamma-secretase subunits nicastrin and APH-1 undergo S-palmitoylation, the post-translational covalent attachment of the long chain fatty acid palmitate common in lipid raft-associated proteins. By mutagenesis we show that nicastrin is S-palmitoylated at Cys(689), and APH-1 is S-palmitoylated at Cys(182) and Cys(245). S-Palmitoylation-defective nicastrin and APH-1 form stable gamma-secretase complexes when expressed in knock-out fibroblasts lacking wild type subunits, suggesting that S-palmitoylation is not essential for gamma-secretase assembly. Nevertheless, fractionation studies show that S-palmitoylation contributes to DRM association of nicastrin and APH-1. Moreover, pulse-chase analyses reveal that S-palmitoylation is important for nascent polypeptide stability of both proteins. Co-expression of S-palmitoylation-deficient nicastrin and APH-1 in cultured cells neither affects Abeta40, Abeta42, and AICD production, nor intramembrane processing of Notch and N-cadherin. Our findings suggest that S-palmitoylation plays a role in stability and raft localization of nicastrin and APH-1, but does not directly modulate gamma-secretase processing of APP and other substrates.


Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/metabolismo , Lipoilación/fisiología , Glicoproteínas de Membrana/metabolismo , Microdominios de Membrana/enzimología , Proteínas de la Membrana/metabolismo , Procesamiento Proteico-Postraduccional/fisiología , Enfermedad de Alzheimer/enzimología , Enfermedad de Alzheimer/genética , Secretasas de la Proteína Precursora del Amiloide/genética , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animales , Antígenos CD/genética , Antígenos CD/metabolismo , Ácido Aspártico Endopeptidasas/genética , Ácido Aspártico Endopeptidasas/metabolismo , Cadherinas/genética , Cadherinas/metabolismo , Línea Celular , Endopeptidasas , Estabilidad de Enzimas/fisiología , Humanos , Glicoproteínas de Membrana/genética , Lípidos de la Membrana/genética , Lípidos de la Membrana/metabolismo , Microdominios de Membrana/genética , Proteínas de la Membrana/genética , Ratones , Péptido Hidrolasas , Receptores Notch/genética , Receptores Notch/metabolismo
8.
Arch Pharm Res ; 31(4): 503-10, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18449509

RESUMEN

Systemic lupus erythematosus (SLE) is characterized by inflammatory and dysregulatory immune responses including overactive B cells, overproduction of proinflammatory cytokines, and T cell hyperactivity. PGE(2) modulates a variety of immune processes at sites of inflammation, including production of inflammatory cytokines. However, the role of PGE(2) in dysregulatory inflammatory and immune responses in lupus remains unclear. We investigated whether PGE(2) mediates production of inflammatory cytokines in pristane-induced lupus BALB/c mice. Our results showed that levels of serum and BAL PGE(2) and LPS-stimulated production of PGE(2) by peritoneal macrophages were remarkably increased in pristane-induced lupus mice compared to healthy controls. Exogenous PGE(2) enhanced production of IL-6, IL-10, and NO but decreased TNF-alpha by macrophages and augmented IFN-gamma, IL-6, and IL-10 by splenocytes from pristane-induced lupus mice compared to healthy controls. Exogenous PGE(2) also enhanced production of IFN-gamma, IL-6, and IL-10 by thymocytes from pristane-induced lupus mice. Indomethacin (Indo), a PGE(2) synthesis inhibitor, greatly inhibited LPS-induced production of IL-6 and IL-10 by macrophages from pristane-induced lupus mice, while enhanced TNF-alpha. Indo remarkably inhibited Con A-increased production of IFN-gamma, IL-6, and IL-10 by splenocytes and thymocytes from pristane-induced lupus mice. Therefore, our findings suggest that endogenous PGE(2) may mediate dysregulation of production of proinflammatory cytokines, such as IL-6, IL-10, and IFN-gamma, and NO in pristane-induced lupus mice.


Asunto(s)
Citocinas/metabolismo , Dinoprostona/metabolismo , Mediadores de Inflamación/metabolismo , Lupus Eritematoso Sistémico/metabolismo , Linfocitos/metabolismo , Macrófagos Peritoneales/metabolismo , Animales , Líquido del Lavado Bronquioalveolar/química , Células Cultivadas , Concanavalina A/farmacología , Inhibidores de la Ciclooxigenasa/farmacología , Dinoprostona/sangre , Modelos Animales de Enfermedad , Femenino , Indometacina/farmacología , Interferón gamma/metabolismo , Interleucina-10/metabolismo , Interleucina-6/metabolismo , Lipopolisacáridos/farmacología , Lupus Eritematoso Sistémico/inducido químicamente , Lupus Eritematoso Sistémico/inmunología , Linfocitos/efectos de los fármacos , Macrófagos Peritoneales/efectos de los fármacos , Ratones , Ratones Endogámicos BALB C , Óxido Nítrico/metabolismo , Bazo/metabolismo , Terpenos , Timo/metabolismo , Factores de Tiempo , Factor de Necrosis Tumoral alfa/metabolismo , Regulación hacia Arriba
9.
Arch Insect Biochem Physiol ; 66(4): 204-13, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18000874

RESUMEN

A new antimicrobial peptide, cryptonin, was isolated and characterized from the adult Korean blackish cicada, Cryptotympana dubia. It consists of 24 amino acid residues and has a molecular weight of 2,704 Da on mass spectroscopy. The predicted alpha-helical structure analysis and increased helix percent in 40% trifloroethanol of cryptonin suggests that it belongs to the typical linear alpha-helix forming peptide. Binding of the biotin-labeled cryptonin at the surface of E. coli cells and increased influx of propidium iodide in E. coli after cryptonin treatment indicates that it kills microbial cells by binding bacterial cell surfaces and disrupting the cell permeability. Cryptonin showed strong antibacterial (MIC 1.56-25 microg/ml) and antifungal (MIC 3.12-50 microg/ml) activities against tested bacteria and fungi including two antibiotic-resistant bacterial strains; methicilin-resistant S. aureus and vancomycin-resistant Enterococci (MIC 25 microg/ml, each).


Asunto(s)
Péptidos Catiónicos Antimicrobianos/metabolismo , Hemípteros/metabolismo , Animales , Péptidos Catiónicos Antimicrobianos/química , Péptidos Catiónicos Antimicrobianos/aislamiento & purificación , Permeabilidad de la Membrana Celular , Dicroismo Circular , Hemípteros/química , Hemolíticos/análisis , Microscopía Confocal , Ratas
10.
Bioorg Med Chem ; 15(20): 6596-607, 2007 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-17681794

RESUMEN

With the goal of developing Alzheimer's disease therapeutics, we have designed and synthesized new piperidine derivatives having dual action of acetylcholinesterase (AChE) and beta-amyloid peptide (Abeta) aggregation inhibition. For binding with the catalytic site of AChE, an ester with aromatic group was designed, and for the peripheral site, another aromatic group was considered. And for intercalating amyloid-beta oligomerization, long and linear conformation with a lipophilic group was considered. The synthetic methods employed for the structure with dual action depended on alcohols with an aromatic ring and the substituted benzoic acids, which are esterificated in the last step of the synthetic pathway. We screened these new derivatives through inhibition tests of acetylcholinesterase, butyrylcholinesterase (BChE), and Abeta(1-42) peptide aggregation, AChE-induced Abeta(1-42) aggregation. Our results displayed that compound 12 showed the best inhibitory potency and selectivity of AChE, and 29 showed the highest selectivity of BChE inhibition. Compounds 15 and 12 had inhibitory activities against Abeta(1-42) aggregation and AChE-induced Abeta aggregation. In the docking model, we confirmed that 4-chlorobenzene of 12 plays the parallel pi-pi stacking against the indole ring of Trp84 in the bottom gorge of AChE. Because the benzyhydryl moiety of 12 covered the peripheral site of AChE in a funnel-like shape, 12 showed good inhibitory potency against AChE and could inhibit AChE-induced Abeta(1-42) peptide aggregation.


Asunto(s)
Acetilcolinesterasa/metabolismo , Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/antagonistas & inhibidores , Inhibidores de la Colinesterasa/síntesis química , Inhibidores de la Colinesterasa/farmacología , Fragmentos de Péptidos/antagonistas & inhibidores , Piperidinas/química , Piperidinas/farmacología , Enfermedad de Alzheimer/tratamiento farmacológico , Péptidos beta-Amiloides/metabolismo , Butirilcolinesterasa/metabolismo , Línea Celular , Supervivencia Celular/efectos de los fármacos , Inhibidores de la Colinesterasa/química , Donepezilo , Humanos , Indanos/síntesis química , Indanos/química , Indanos/farmacocinética , Modelos Moleculares , Estructura Molecular , Fragmentos de Péptidos/metabolismo , Piperidinas/síntesis química , Piperidinas/farmacocinética , Estructura Terciaria de Proteína , Relación Estructura-Actividad
12.
J Biol Chem ; 278(5): 3446-54, 2003 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-12435726

RESUMEN

Presenilins (PS1/PS2) play a critical role in proteolysis of beta-amyloid precursor protein (beta APP) to generate beta-amyloid, a peptide important in the pathogenesis of Alzheimer's disease. Nevertheless, several regulatory functions of PS1 have also been reported. Here we demonstrate, in neuroblastoma cells, that PS1 regulates the biogenesis of beta APP-containing vesicles from the trans-Golgi network and the endoplasmic reticulum. PS1 deficiency or the expression of loss-of-function variants leads to robust vesicle formation, concomitant with increased maturation and/or cell surface accumulation of beta APP. In contrast, release of vesicles containing beta APP is impaired in familial Alzheimer's disease (FAD)-linked PS1 mutant cells, resulting in reduced beta APP delivery to the cell surface. Moreover, diminution of surface beta APP is profound at axonal terminals in neurons expressing a PS1 FAD variant. These results suggest that PS1 regulation of beta APP trafficking may represent an alternative mechanism by which FAD-linked PS1 variants modulate beta APP processing.


Asunto(s)
Precursor de Proteína beta-Amiloide/metabolismo , Aparato de Golgi/metabolismo , Proteínas de la Membrana/metabolismo , Red trans-Golgi/metabolismo , Precursor de Proteína beta-Amiloide/genética , Animales , Biotinilación , Membrana Celular/metabolismo , Permeabilidad de la Membrana Celular/fisiología , Retículo Endoplásmico/metabolismo , Humanos , Cinética , Proteínas de la Membrana/genética , Ratones , Microscopía Confocal , Modelos Biológicos , Neuroblastoma , Presenilina-1 , Transporte de Proteínas , Proteínas Recombinantes/metabolismo , Transfección , Células Tumorales Cultivadas
13.
Neurobiol Dis ; 11(1): 64-82, 2002 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-12460547

RESUMEN

Presenilin 1 (PS1) and presenilin 2 play a critical role in the gamma-secretase processing of amyloid precursor protein (APP) and Notch1. Here, we investigate maturation and intracellular trafficking of APP and other membrane proteins in cells expressing an experimental PS1 deletion mutant (deltaM1,2). Stable expression of deltaM1,2 impairs gamma-secretase processing of Notch1 and delays Abeta secretion. Kinetic studies show enhanced O-glycosylation and sialylation of holo-APP and marked accumulation of APP COOH-terminal fragments (CTFs). Surface biotinylation, live staining, and trafficking studies show increased surface accumulation of holo-APP and CTFs in deltaM1,2 cells resulting from enhanced surface delivery of newly synthesized APP. Expression of a loss-of-function PS1 mutant (D385A) or incubation of cells with gamma-secretase inhibitors also increases surface levels of holo-APP and CTFs. In contrast to APP, glycosylation and surface accumulation of another type I membrane protein, nicastrin, are markedly reduced in deltaM1,2 cells. Finally, expression of deltaM1,2 results in the increased assembly and surface expression of nicotinic acetylcholine receptors, illustrating that PS1's influence on protein trafficking extends beyond APP and other type I membrane protein substrates of gamma-secretase. Collectively, our findings provide evidence that PS1 regulates the glycosylation and intracellular trafficking of APP and select membrane proteins.


Asunto(s)
Precursor de Proteína beta-Amiloide/metabolismo , Eliminación de Gen , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Secretasas de la Proteína Precursora del Amiloide , Péptidos beta-Amiloides/metabolismo , Animales , Ácido Aspártico Endopeptidasas , Células Cultivadas , Endopeptidasas/metabolismo , Expresión Génica , Glicosilación , Humanos , Glicoproteínas de Membrana/metabolismo , Proteínas de la Membrana/química , Fragmentos de Péptidos/metabolismo , Presenilina-1 , Presenilina-2 , Estructura Terciaria de Proteína , Transporte de Proteínas/fisiología , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo
14.
J Biol Chem ; 277(21): 19236-40, 2002 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-11943765

RESUMEN

Proteolytic processing of amyloid precursor protein generates beta-amyloid (Abeta) peptides that are deposited in senile plaques in brains of aged individuals and patients with Alzheimer's disease. Presenilins (PS1 and PS2) facilitate the final step in Abeta production, the intramembranous gamma-secretase cleavage of amyloid precursor protein. Biochemical and pharmacological evidence support a catalytic or accessory role for PS1 in gamma-secretase cleavage, as well as a regulatory role in select membrane protein trafficking. In this report, we demonstrate that PS1 is required for maturation and cell surface accumulation of nicastrin, an integral component of the multimeric gamma-secretase complex. Using kinetic labeling studies we show that in PS1(-/-)/PS2(-/-) cells nicastrin fails to reach the medial Golgi compartment, and as a consequence, is incompletely glycosylated. Stable expression of human PS1 restores these deficiencies in PS1(-/-) fibroblasts. Moreover, membrane fractionation studies show co-localization of PS1 fragments with mature nicastrin. These results indicate a novel chaperone-type role for PS1 and PS2 in facilitating nicastrin maturation and transport in the early biosynthetic compartments. Our findings are consistent with PS1 influencing gamma-secretase processing at multiple steps, including maturation and intracellular trafficking of substrates and component(s) of the gamma-secretase complex.


Asunto(s)
Glicoproteínas de Membrana/metabolismo , Proteínas de la Membrana/fisiología , Secretasas de la Proteína Precursora del Amiloide , Animales , Ácido Aspártico Endopeptidasas , Membrana Celular/metabolismo , Endopeptidasas/metabolismo , Ratones , Presenilina-1 , Transporte de Proteínas , Fracciones Subcelulares/metabolismo , Células Tumorales Cultivadas
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