RESUMEN
Idiopathic basal ganglia calcification (IBGC) is a rare neurodegenerative disease, characterized by abnormal calcium deposits in basal ganglia of the brain. The affected individuals exhibit movement disorders, and progressive deterioration of cognitive and psychiatric ability. The genetic cause of the disease is mutation in one of several different genes, SLC20A2, PDGFB, PDGFRB, XPR1 or MYORG, which inheritably or sporadically occurs. Here we generated an induced pluripotent stem cell (iPSC) line from an IBGC patient, which is likely be a powerful tool for revealing the pathomechanisms and exploring potential therapeutic candidates of IBGC.
Asunto(s)
Enfermedades de los Ganglios Basales , Células Madre Pluripotentes Inducidas , Enfermedades Neurodegenerativas , Ganglios Basales/metabolismo , Enfermedades de los Ganglios Basales/genética , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Mutación , Enfermedades Neurodegenerativas/genética , Proteínas Cotransportadoras de Sodio-Fosfato de Tipo III/genética , Receptor de Retrovirus Xenotrópico y PolitrópicoRESUMEN
OBJECTIVE: Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is caused by mutations in CSF1R. Pathogenic mutations in exons 12-22 including coding sequence of the tyrosine kinase domain (TKD) of CSF1R were previously identified. We aimed to identify CSF1R mutations in patients who were clinically suspected of having ALSP and to determine the pathogenicity of novel CSF1R variants. METHODS: Sixty-one patients who fulfilled the diagnostic criteria of ALSP were included in this study. Genetic analysis of CSF1R was performed for all the coding exons. The haploinsufficiency of CSF1R was examined for frameshift mutations by RT-PCR. Ligand-dependent autophosphorylation of CSF1R was examined in cells expressing CSF1R mutants. RESULTS: We identified ten variants in CSF1R including two novel frameshift, five novel missense, and two known missense mutations as well as one known missense variant. Eight mutations were located in TKD. One frameshift mutation (p.Pro104LeufsTer8) and one missense variant (p.His362Arg) were located in the extracellular domain. RT-PCR analysis revealed that the frameshift mutation of p.Pro104LeufsTer8 caused nonsense-mediated mRNA decay. Functional assay revealed that none of the mutations within TKD showed autophosphorylation of CSF1R. The p.His362Arg variant located in the extracellular domain showed comparable autophosphorylation of CSF1R to the wild type, suggesting that this variant is not likely pathogenic. CONCLUSIONS: The detection of the CSF1R mutation outside of the region-encoding TKD may extend the genetic spectrum of ALSP with CSF1R mutations. Mutational analysis of all the coding exons of CSF1R should be considered for patients clinically suspected of having ALSP.
Asunto(s)
Mutación del Sistema de Lectura , Leucoencefalopatías/genética , Mutación Missense , Receptores de Factor Estimulante de Colonias de Granulocitos y Macrófagos/genética , Adulto , Anciano , Encéfalo/diagnóstico por imagen , Encéfalo/metabolismo , Encéfalo/patología , Análisis Mutacional de ADN , Exones , Femenino , Células HEK293 , Haploinsuficiencia , Humanos , Leucoencefalopatías/diagnóstico por imagen , Leucoencefalopatías/metabolismo , Leucoencefalopatías/patología , Masculino , Persona de Mediana Edad , Fosforilación , ARN Mensajero/metabolismo , Receptores de Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Adulto JovenRESUMEN
BACKGROUND: Our previous randomized double-blind study showed that drinking hydrogen (H2) water for 48 weeks significantly improved the total Unified Parkinson's Disease Rating Scale (UPDRS) score of Parkinson's disease (PD) patients treated with levodopa. We aim to confirm this result using a randomized double-blind placebo-controlled multi-center trial. METHODS: Changes in the total UPDRS scores from baseline to the 8(th), 24(th), 48(th), and 72(nd) weeks, and after the 8(th) week, will be evaluated. The primary endpoint of the efficacy of this treatment in PD is the change in the total UPDRS score from baseline to the 72(nd) week. The changes in UPDRS part II, UPDRS part III, each UPDRS score, PD Questionnaire-39 (PDQ-39), and the modified Hoehn and Yahr stage at these same time-points, as well as the duration until the protocol is finished because additional levodopa is required or until the disease progresses, will also be analyzed. Adverse events and screening laboratory studies will also be examined. Participants in the hydrogen water group will drink 1000 mL/day of H2 water, and those in the placebo water group will drink normal water. One-hundred-and-seventy-eight participants with PD (88 women, 90 men; mean age: 64.2 [SD 9.2] years, total UPDRS: 23.7 [11.8], with levodopa medication: 154 participants, without levodopa medication: 24 participants; daily levodopa dose: 344.1 [202.8] mg, total levodopa equivalent dose: 592.0 [317.6] mg) were enrolled in 14 hospitals and were randomized. DISCUSSION: This study will confirm whether H2 water can improve PD symptoms. TRIAL REGISTRATION: UMIN000010014 (February, 13, 2013).
Asunto(s)
Hidrógeno/uso terapéutico , Enfermedad de Parkinson/tratamiento farmacológico , Agua , Anciano , Antiparkinsonianos/uso terapéutico , Método Doble Ciego , Femenino , Humanos , Levodopa/uso terapéutico , Masculino , Persona de Mediana EdadRESUMEN
Neural stem/progenitor cells (NSPCs) proliferate and differentiate depending on their intrinsic properties and local environment. During the development of the mammalian nervous system, NSPCs generate neurons and glia sequentially. However, little is known about the mechanism that determines the timing of switch from neurogenesis to gliogenesis. In this study, we established a culture system in which the neurogenic potential of NSPCs is decreased in a time-dependent manner, so that short-term-cultured NSPCs differentiate into more neurons compared with long-term-cultured NSPCs. We found that short-term-cultured NSPCs express high levels of integrin-associated protein form 2 (IAP2; so-called CD47) mRNA using differential display analysis. Moreover, IAP2 overexpression in NSPCs induced neuronal differentiation of NSPCs. These findings reveal a novel mechanism by which IAP2 induces neuronal differentiation of NSPCs.
Asunto(s)
Antígeno CD47/metabolismo , Células-Madre Neurales/citología , Neurogénesis/fisiología , Neuronas/citología , Animales , Células Cultivadas , Células-Madre Neurales/metabolismo , Neuronas/metabolismo , Ratas , Ratas WistarRESUMEN
The diagnosis of idiopathic normal pressure hydrocephalus (iNPH) is sometimes complicated by concomitant Alzheimer's disease (AD) pathology. The purpose of the present study is to identify an iNPH-specific cerebrospinal fluid (CSF) biomarker dynamics and to assess its ability to differentiate iNPH from AD. Total tau (t-tau), tau phosphorylated at threonine 181 (p-tau), amyloid-ß (Aß) 42 and 40, and leucine-rich α-2-glycoprotein (LRG) were measured in 93 consecutive CSF samples consisting of 55 iNPH (46 tap test responders), 20 AD, 11 corticobasal syndrome, and 7 spinocerebeller disease. Levels of t-tau and p-tau were significantly decreased in iNPH patients especially in tap test responders compared to AD. Correlation was observed between Mini-Mental State Examination scores and Aß42 in AD (R = 0.44) and mildly in iNPH (R = 0.28). Although Aß42/40 ratio showed no significant difference between iNPH and AD (p = 0.08), the levels of Aß40 and Aß42 correlated positively with each other in iNPH (R = 0.73) but much less in AD (R = 0.26), suggesting that they have discrete amyloid clearance and pathology. LRG levels did not differ between the two. Thus, our study shows that although CSF biomarkers of iNPH patients can be affected by concomitant tau and/or amyloid pathology, CSF t-tau and p-tau are highly useful for differentiation of iNPH and AD.
Asunto(s)
Enfermedad de Alzheimer/líquido cefalorraquídeo , Biomarcadores/líquido cefalorraquídeo , Hidrocéfalo Normotenso/líquido cefalorraquídeo , Anciano , Anciano de 80 o más Años , Péptidos beta-Amiloides/líquido cefalorraquídeo , Análisis de Varianza , Área Bajo la Curva , Encefalopatías/líquido cefalorraquídeo , Distribución de Chi-Cuadrado , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fragmentos de Péptidos/líquido cefalorraquídeo , Estudios Retrospectivos , alfa-Macroglobulinas/líquido cefalorraquídeo , Proteínas tau/líquido cefalorraquídeoRESUMEN
Drug adherence is central to the treatment of dementia, which might reduce compliance due to memory loss, particularly among home-based patients with dementia. In order to improve drug adherence, we suggest the efficient and effective supervised administration by use of information communication technology(ICT). ICT makes face-to-face real-time communication possible, and it also enables picture sharing. Therefore, it might be useful to apply ICT to controlling and supervising medication for patients with dementia to improve drug adherence. Accordingly, we enrolled patients who were supposed to take a newly prescribed anti-dementia patch containing the choline esterase inhibitor rivastigmine(Rivastach®)and investigated the effect of ICT-based intervention for drug adherence, emotional change, and cognitive change, utilizing Skype, a free communication software program. Scheduled Skype interventions increased drug adherence ratio, levels of subjective satisfaction, and instrumental activities of daily living(IADL). Furthermore, we can provide patients and their caregivers with a feeling of safety through regular bidirectional communication, as patients can easily consult medical staff regarding the adverse effects of newly prescribed drugs. Instead of frequent visits to their primary physicians, ICT-based communications can be used as a substitute for supervision of medication, given the availability of the telecommunication system. By directly connecting the medical institution to the home, we expect that this ICT-based system will expand into the geriatric care field, including the care of elderly individuals living alone.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Telemedicina , Anciano , Anciano de 80 o más Años , Cuidadores , Cognición , Femenino , Servicios de Atención de Salud a Domicilio , Humanos , Masculino , Persona de Mediana EdadRESUMEN
High fat diet (HFD) is prevalent in many modern societies and HFD-induced metabolic condition is a growing concern worldwide. It has been previously reported that HFD clearly worsens cognitive function in amyloid precursor protein (APP) transgenic mice. On the other hand, we have demonstrated that voluntary exercise in an enriched environment is an effective intervention to rescue HFD-induced ß-amyloid (Aß) deposition and memory deficit. However, it had been unclear whether consumption of HFD after exercising abolished the beneficial effect of exercise on the inhibition of Alzheimer's disease (AD) pathology. To examine this question, we exposed wild type (WT) and APP mice fed with HFD to exercise conditions at different time periods. In our previous experiment, we gave HFD to mice for 20 weeks and subjected them to exercise during weeks 10-20. In the present study, mice were subjected to exercise conditions during weeks 0-10 or weeks 5-15 while being on HFD. Interestingly, we found that the effect of exercise during weeks 0-10 or weeks 5-15 on memory function was not abolished in WT mice even if they kept having HFD after finishing exercise. However, in APP transgenic mice, HFD clearly disrupted the effect of exercise during weeks 0-10 or weeks 5-15 on memory function. Importantly, we observed that the level of Aß oligomer was significantly elevated in the APP mice that exercised during weeks 0-10: this might have been caused by the up-regulation of Aß production. These results provide solid evidence that continuation of exercise is necessary to rescue HFD-induced aggravation of cognitive decline in the pathological setting of AD.
Asunto(s)
Precursor de Proteína beta-Amiloide/metabolismo , Dieta Alta en Grasa/efectos adversos , Trastornos de la Memoria/metabolismo , Trastornos de la Memoria/terapia , Condicionamiento Físico Animal/fisiología , Amiloide , Animales , Ensayo de Inmunoadsorción Enzimática , Femenino , Immunoblotting , Masculino , RatonesRESUMEN
Alzheimer's disease (AD) is characterized by the deposition of amyloid-ß (Aß) plaques, senile plaque. The Aß peptide is cleaved from amyloid precursor protein (APP) by ß-secretase and γ-secretase. Until now, many literatures have documented that the high concentration of copper is present in Aß plaques and enhances aggregation of. The APP copper binding domain (CuBD) is located in the N-terminal next to the growth factor-like domain that gets involved in APP homodimerization. Importantly, dimerization of APP has profound effect on Aß production. We investigated whether copper alters the state of APP dimerization and how it affects APP metabolism. Here, we demonstrate that copper enhanced APP dimerization and increased extracellular release of Aß. Moreover, copper chelator, D-penicillamine, suppressed APP dimerization and decreased extracellular release of Aß. These results suggest that the action of copper may be profoundly associated with the pathway of Aß production in AD pathogenesis.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Cobre/metabolismo , Multimerización de Proteína , Precursor de Proteína beta-Amiloide/química , Western Blotting , Ensayo de Inmunoadsorción Enzimática , Técnica del Anticuerpo Fluorescente , Células HEK293 , Humanos , InmunoprecipitaciónRESUMEN
In our laboratory, we draw up research aims to improve medication compliance in patients with dementia by video phone, and we have intervened in the cases of 3 patients to date. In this study, we focused on patients who are using a rivastigmine patch for Alzheimer' disease, which can be confirmed by video phone, to examine its efficacy. Specifically, by monitoring the effects of the treatment, skin side effects, of skin and usability for patients and caregivers, we monitor the dosing schedule to prevent interruption of self-medication, with the aim of improving compliance and treatment efficacy. We also consider methods of intervention for increasing the persistence rate of the rivastigmine patch and quality of life(QOL)by using the effectiveness of the video phone to focus on the symptoms of skin side effects. In addition, we examine the interventions that reduce the care burden and anxiety of caregivers by listening during the regular intervention.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Monitoreo de Drogas/instrumentación , Internet , HumanosRESUMEN
Bicalutamide is an anti-androgen that is used worldwide to treat prostate cancer (CaP). However, there are no data on blood bicalutamide concentrations in hemodialysis (HD) patients with CaP. Therefore, we investigated the plasma levels of bicalutamide during the peridialysis period in this population. The study group included 5 HD patients with CaP who had been treated with bicalutamide (80 mg/day) for at least 3 months. Blood samples were taken during and between HD sessions and the plasma concentrations of the active R enantiomer (R-bicalutamide) were assessed using an HPLC assay. The plasma R-bicalutamide levels on the non-dialysis day were measured in 2 patients (patients 1 and 2) immediately before dosing and 8 and 24 h after dosing. These levels were 18,730, 19,090 and 19,420 ng/ml (patient 1), and 4,522, 4,581, and 5,296 ng/ml (patient 2), respectively. The mean plasma levels of R-bicalutamide in all 5 subjects just before HD, and 2 and 4 h after the start of HD were 8,726, 9,354 and 10,068 ng/ml, respectively. These results show that bicalutamide does not accumulate and is not diluted in the blood circulation of HD patients when given at the normal dosage used in the general population.
Asunto(s)
Anilidas/sangre , Fallo Hepático/complicaciones , Fallo Hepático/tratamiento farmacológico , Nitrilos/sangre , Neoplasias de la Próstata/complicaciones , Neoplasias de la Próstata/tratamiento farmacológico , Diálisis Renal/métodos , Compuestos de Tosilo/sangre , Anciano , Anilidas/farmacocinética , Antineoplásicos/sangre , Antineoplásicos/farmacocinética , Cromatografía Líquida de Alta Presión/métodos , Humanos , Masculino , Persona de Mediana Edad , Nitrilos/farmacocinética , Estereoisomerismo , Factores de Tiempo , Compuestos de Tosilo/farmacocinéticaRESUMEN
Rotenone, a mitochondrial complex I inhibitor, has been used to generate animal and cell culture models of Parkinson's disease. Recent studies suggest that microtubule destabilization causes selective dopaminergic neuronal loss. In this study, we investigated glycogen synthase kinase-3ß (GSK3ß) involvement in rotenone-induced microtubule destabilization. Rotenone-induced cytotoxicity in SH-SY5Y cells was attenuated by the GSK3ß inhibitor SB216763. Tau, a microtubule-associated protein and substrate for GSK3ß, has been implicated in the pathogenesis of tauopathies such as Alzheimer's disease. Rotenone induced an increase in phosphorylated tau, the effect of which was attenuated by concomitant treatment with SB216763. Rotenone treatment also decreased tau expression in the microtubule fraction and increased tau expression in the cytosol fraction. These effects were suppressed by SB216763, which suggests that rotenone reduces the capacity of tau to bind microtubules. Rotenone treatment increased the amount of free tubulin and reduced the amount of polymerized tubulin, indicating that rotenone destabilizes microtubules. Rotenone-induced microtubule destabilization was suppressed by SB216763 and taxol, a microtubule stabilizer. Taxol prevented rotenone-induced cytotoxicity and morphological changes. Taken together, these results suggest that rotenone-induced cytotoxicity is mediated by microtubule destabilization via GSK3ß activation, and that microtubule destabilization is caused by reduction in the binding capacity of tau to microtubules, which is a result of tau phosphorylation via GSK3ß activation.
Asunto(s)
Complejo I de Transporte de Electrón/antagonistas & inhibidores , Glucógeno Sintasa Quinasa 3/metabolismo , Microtúbulos/efectos de los fármacos , Rotenona/farmacología , Moduladores de Tubulina/farmacología , Línea Celular Tumoral , Glucógeno Sintasa Quinasa 3/genética , Glucógeno Sintasa Quinasa 3 beta , Humanos , Indoles/farmacología , Maleimidas/farmacología , Microtúbulos/metabolismo , Paclitaxel/farmacología , Enfermedad de Parkinson Secundaria/inducido químicamente , Enfermedad de Parkinson Secundaria/metabolismo , Fosforilación , Especies Reactivas de Oxígeno/metabolismo , Proteínas tau/metabolismoRESUMEN
Accumulating evidence suggests that some dietary patterns, specifically high fat diet (HFD), increase the risk of developing sporadic Alzheimer disease (AD). Thus, interventions targeting HFD-induced metabolic dysfunctions may be effective in preventing the development of AD. We previously demonstrated that amyloid precursor protein (APP)-overexpressing transgenic mice fed HFD showed worsening of cognitive function when compared with control APP mice on normal diet. Moreover, we reported that voluntary exercise ameliorates HFD-induced memory impairment and ß-amyloid (Aß) deposition. In the present study, we conducted diet control to ameliorate the metabolic abnormality caused by HFD on APP transgenic mice and compared the effect of diet control on cognitive function with that of voluntary exercise as well as that of combined (diet control plus exercise) treatment. Surprisingly, we found that exercise was more effective than diet control, although both exercise and diet control ameliorated HFD-induced memory deficit and Aß deposition. The production of Aß was not different between the exercise- and the diet control-treated mice. On the other hand, exercise specifically strengthened the activity of neprilysin, the Aß-degrading enzyme, the level of which was significantly correlated with that of deposited Aß in our mice. Notably, the effect of the combination treatment (exercise and diet control) on memory and amyloid pathology was not significantly different from that of exercise alone. These studies provide solid evidence that exercise is a useful intervention to rescue HFD-induced aggravation of cognitive decline in transgenic model mice of AD.
Asunto(s)
Enfermedad de Alzheimer/prevención & control , Péptidos beta-Amiloides/genética , Grasas de la Dieta/farmacología , Trastornos de la Memoria/prevención & control , Condicionamiento Físico Animal/fisiología , Enfermedad de Alzheimer/dietoterapia , Enfermedad de Alzheimer/genética , Péptidos beta-Amiloides/metabolismo , Alimentación Animal , Animales , Cognición/fisiología , Modelos Animales de Enfermedad , Femenino , Humanos , Hipercolesterolemia/dietoterapia , Hipercolesterolemia/genética , Hiperinsulinismo/dietoterapia , Hiperinsulinismo/genética , Masculino , Trastornos de la Memoria/dietoterapia , Trastornos de la Memoria/genética , Enfermedades Metabólicas/dietoterapia , Enfermedades Metabólicas/genética , Ratones , Ratones Transgénicos , Neprilisina/metabolismo , Obesidad/dietoterapia , Obesidad/genéticaRESUMEN
We have recently reported that Presenilin 1 (PS1), a causative gene of familial Alzheimer disease (AD), down-regulates the expression level of insulin receptor (IR) as well as its signaling through a γ-secretase-independent pathway. PS1 is phosphorylated by glycogen synthase kinase 3 ß at the serine 353 and 357 residues. The main purpose of the present study was to clarify the effect of PS1 phosphorylation on IR/insulin signaling. Here, we demonstrate that the pseudo-phosphorylation mutant of PS1 inhibited IR transcription and reduced IR expression compared with wild-type PS1. Importantly, there was a decrease in expression of IR in AD brains, and the phosphorylation ratio of PS1 was negatively correlated with IR level in human brain samples. In the data from mouse models of AD, IR reduction was not observed at the pre-Aß deposition stage but became apparent in that of post-Aß deposition. Together with our previous reports, these results suggest that phosphorylated PS1 can promote the down-regulation of insulin signaling, which may be a positive feed-forward mechanism inhibiting insulin signaling. As insulin resistance is reported to be a risk factor for sporadic AD, this PS1-mediated regulatory mechanism of brain insulin signaling may be causally associated with AD pathology.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Insulina/metabolismo , Presenilina-1/metabolismo , Receptor de Insulina/metabolismo , Transducción de Señal/fisiología , Anciano , Anciano de 80 o más Años , Animales , Encéfalo/metabolismo , Modelos Animales de Enfermedad , Regulación hacia Abajo , Femenino , Humanos , Masculino , Ratones , Ratones Transgénicos , Persona de Mediana Edad , FosforilaciónRESUMEN
The pathogenesis of Alzheimer's disease (AD) is tightly associated with metabolic dysfunctions. In particular, a potential link between type 2 diabetes (T2DM) and AD has been suggested epidemiologically, clinically, and experimentally, and some studies have suggested that exercise or dietary intervention reduces risk of cognitive decline. However, there is little solid molecular evidence for the effective intervention of metabolic dysfunctions for prevention of AD. In the present study, we established the AD model mice with diabetic conditions through high-fat diet (HFD) to examine the effect of environmental enrichment (EE) on HFD-induced AD pathophysiology. Here, we demonstrated that HFD markedly deteriorated memory impairment and increased ß-amyloid (Aß) oligomers as well as Aß deposition in amyloid precursor protein (APP) transgenic mice, which was reversed by exposure to an enriched environment for 10 weeks, despite the continuation of HFD. These studies provide solid evidence that EE is a useful intervention to ameliorate behavioral changes and AD pathology in HFD-induced aggravation of AD symptoms in APP transgenic mice.
Asunto(s)
Péptidos beta-Amiloides/metabolismo , Grasas de la Dieta/toxicidad , Exposición a Riesgos Ambientales , Trastornos de la Memoria/metabolismo , Trastornos de la Memoria/prevención & control , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/terapia , Péptidos beta-Amiloides/antagonistas & inhibidores , Péptidos beta-Amiloides/genética , Animales , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Grasas de la Dieta/antagonistas & inhibidores , Modelos Animales de Enfermedad , Femenino , Humanos , Masculino , Trastornos de la Memoria/genética , Ratones , Ratones TransgénicosRESUMEN
FE65 is reported to act as an adaptor protein with several protein-interaction domains, including one WW domain and two phosphotyrosine interaction/binding domains. Through these binding domains, FE65 was considered to recruit various binding partners together to form functional complexes in a certain cellular compartment. In this study, we demonstrated that Rac1, a member of the Rho family GTPases, bound with FE65. We also elucidated that Rac1 inhibitor significantly suppressed FE65 expression, and Rac1 small interfering RNA transduction significantly decreased FE65 expression. FE65 small interfering RNA, however, did not influence Rac1 expression and its activity. Taken together, our results reveal that Rac1 interacts with FE65, and Rac1 activity regulates FE65 expression.
Asunto(s)
Proteínas del Tejido Nervioso/metabolismo , Neuropéptidos/fisiología , Proteínas Nucleares/metabolismo , Proteínas de Unión al GTP rac/fisiología , Animales , Células Cultivadas , Hipocampo/metabolismo , Masculino , Ratones , Ratones Endogámicos ICR , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Neuropéptidos/genética , Neuropéptidos/metabolismo , Proteínas Nucleares/antagonistas & inhibidores , Unión Proteica/fisiología , Mapeo de Interacción de Proteínas , ARN Interferente Pequeño/fisiología , Proteínas de Unión al GTP rac/genética , Proteínas de Unión al GTP rac/metabolismo , Proteína de Unión al GTP rac1RESUMEN
Sequential processing of amyloid precursor protein (APP) by ß- and γ-secretase leads to the generation of amyloid-ß (Aß) peptides, which plays a central role in Alzheimer's disease pathogenesis. APP is capable of forming a homodimer through its extracellular domain as well as transmembrane GXXXG motifs. A number of reports have shown that dimerization of APP modulates Aß production. On the other hand, we have previously reported that N-cadherin-based synaptic contact is tightly linked to Aß production. In the present report, we investigated the effect of N-cadherin expression on APP dimerization and metabolism. Here, we demonstrate that N-cadherin expression facilitates cis-dimerization of APP. Moreover, N-cadherin expression led to increased production of Aß as well as soluble APPß, indicating that ß-secretase-mediated cleavage of APP is enhanced. Interestingly, N-cadherin expression affected neither dimerization of C99 nor Aß production from C99, suggesting that the effect of N-cadherin on APP metabolism is mediated through APP extracellular domain. We confirmed that N-cadherin enhances APP dimerization by a novel luciferase-complementation assay, which could be a platform for drug screening on a high-throughput basis. Taken together, our results suggest that modulation of APP dimerization state could be one of mechanisms, which links synaptic contact and Aß production.
Asunto(s)
Péptidos beta-Amiloides/biosíntesis , Precursor de Proteína beta-Amiloide/metabolismo , Cadherinas/farmacología , Espacio Extracelular/metabolismo , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Western Blotting , Cadherinas/antagonistas & inhibidores , Adhesión Celular/efectos de los fármacos , Dimerización , Espacio Extracelular/efectos de los fármacos , Células HEK293 , Humanos , Inmunoprecipitación , Indicadores y Reactivos , Plásmidos/genética , TransfecciónRESUMEN
Presenilin (PS), a causative molecule of familial Alzheimer disease, acts as a crucial component of the γ-secretase complex, which is required to cleave type I transmembrane proteins such as amyloid precursor protein and Notch. However, it also functions through γ-secretase-independent pathways. Recent reports suggested that PS could regulate the expression level of cell surface receptors, including the PDGF and EGF receptors, followed by modulating their downstream pathways via γ-secretase-independent mechanisms. The main purpose of this study was to clarify the effect of PS on expression of the insulin receptor (IR) as well as on insulin signaling. Here, we demonstrate that PS inhibited IR transcription and reduced IR expression, and this was followed by down-regulation of insulin signaling. Moreover, we suggest that neither γ-secretase activity nor Wnt/ß-catenin signaling can reduce the expression of IR, but a PS-mediated increase in the intracellular Ca(2+) level can be associated with it. These results clearly indicate that PS can functionally regulate insulin signaling by controlling IR expression.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/metabolismo , Señalización del Calcio/fisiología , Regulación de la Expresión Génica/fisiología , Insulina/metabolismo , Presenilinas/metabolismo , Receptor de Insulina/biosíntesis , Secretasas de la Proteína Precursora del Amiloide/genética , Animales , Calcio/metabolismo , Células Cultivadas , Insulina/genética , Ratones , Ratones Noqueados , Presenilinas/genética , Receptor de Insulina/genética , Proteínas Wnt/genética , Proteínas Wnt/metabolismo , Vía de Señalización Wnt/fisiología , beta Catenina/genética , beta Catenina/metabolismoRESUMEN
Recently, insulin signaling has been highlighted in the pathology of Alzheimer's disease (AD). Although the association between insulin signaling and Tau pathology has been investigated in several studies, the interaction between insulin signaling and Presenilin 1 (PS1), a key molecule of amyloid beta (Abeta) pathology, has not been elucidated so far. In this study, we demonstrated that insulin inhibited PS1 phosphorylation at serine residues (serine 353, 357) via phosphatidylinositol 3-kinase (PI3K)/Akt signal pathway and strengthened the trimeric complex of PS1/N-cadherin/beta-catenin, consequently relocalizing PS1 to the cell surface. Since our recent report suggests that PS1/N-cadherin/beta-catenin complex regulates Abeta production, it is likely that insulin signaling affects Abeta pathology by regulating PS1 localization.