RESUMEN

Depression in later life is associated with dementia. Changes in motivated behavior are an important mechanism contributing to dysfunctional cognitive control in depression. Although continuous intake of quercetin-rich onion suppresses cognitive decline in aged people by improving their emotional condition, the effect of quercetin-rich onion on emotional condition in people living with cognitive impairment remains unclear. In this randomized, double-blind, placebo-controlled study of subjects with cognitive impairment, we found that subjects wrote more adjectives and adverbs per sentence on the Mini-Mental State Examination after intake of quercetin-rich onion powder than before intake, although regional cerebral blood flow on n-isopropyl-4-[123]iodoamphetamine hydrochloride single-photon emission computed tomography was not changed. In the EPM, mice that had received a quercetin-supplemented chow diet made a significantly increased number of exploratory head dips from the open arms of the maze. Moreover, the 3-methoxycarbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl decay rate, reflecting redox activity, was increased in mice fed a quercetin-added diet. These results indicate that quercetin-rich onion may affect motivated behavior in subjects with cognitive impairment, for whom quercetin intake may preserve redox homeostasis in the brain.

RESUMEN

Alzheimer's disease (AD) causes neurodegeneration, leading to cognitive impairment and memory loss. Our previous studies have demonstrated that the induction of growth arrest and DNA damage-inducible gene 34 (GADD34) by quercetin can affect eukaryotic translation initiation factor 2α (eIF2α) phosphorylation-activated transcription factor 4 (ATF4) signaling. However, the relationship between GADD34 expression and cognitive function has not been clarified. In this study, we determined the direct effect of GADD34 on memory. To achieve this, truncated GADD34 (GADD34.5) was injected into the mouse brain to suppress eIF2α phosphorylation and evaluate memory. The injection of GADD34.5 into the hippocampus in AD-model mice did not improve novel object recognition but improved novel object location. The injection of GADD34.5 into the amygdala also resulted in the maintenance of contextual fear memory based on the fear condition test. These results suggest that GADD34 is effective in improving memory for spatial cognition and contextual fear conditioning in AD by inhibiting eIF2α phosphorylation. In summary, GADD34 suppresses eIF2α phosphorylation in the brain and prevents memory loss. As quercetin feeding increases GADD34 expression, it might be used in preventative applications for AD.

Asunto(s)

Enfermedad de Alzheimer , Ratones , Animales , Enfermedad de Alzheimer/metabolismo , Fosforilación , Quercetina , Factor 2 Eucariótico de Iniciación/metabolismo , Cognición , Trastornos de la Memoria , Proteína Fosfatasa 1/metabolismo

RESUMEN

Adult hippocampal neurogenesis (AHN) plays an important role in hippocampus-dependent function. The number of doublecortin (Dcx)-positive immature neurons in the dentate gyrus decreases over time, especially in the early stages of Alzheimer's disease (AD), and is further reduced in later stages of AD. Obesity in midlife is associated with dementia later in life; however, the underlying mechanisms by which obesity results in the development of dementia later in life remain unknown. Here, we show that endoplasmic reticulum (ER) stress was activated in the hippocampus and processes of Dcx-expressing immature neurons were shortened, coexpressing CHOP in APP23 AD model mice with high-fat diet-induced long-term obesity and in aged Leprdb/db (db/db) mice. Moreover, in cells differentiating from hippocampal neurospheres, Dcx mRNA was rapidly degraded via a microRNA (miRNA) pathway after thapsigargin treatment in vitro. These results indicate that loss of Dcx mRNA induced by ER stress during AHN may cause memory impairment in obese individuals later in life.

Asunto(s)

Proteínas de Dominio Doblecortina/metabolismo , Estrés del Retículo Endoplásmico/fisiología , Neuronas/metabolismo , Obesidad/complicaciones , Envejecimiento , Animales , Conducta Animal/fisiología , Células Cultivadas , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Proteínas de Dominio Doblecortina/genética , Hipocampo , Memoria , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Obesidad/fisiopatología , Tapsigargina/administración & dosificación

RESUMEN

Alzheimer's disease (AD) is the most common cause of dementia in the elderly population. Inflammation plays an important role in AD, as microglia respond to several pathological insults, such as Aß, and exert protective homeostatic functions (anti-inflammatory) and detrimental inflammatory functions (proinflammatory). During the development of AD, chronic inflammation that accompanies aging causes microglial priming, a state of hyperactivation in response to stimulation, indicating that suppressing microglial priming may be a therapeutic intervention for AD. Endoplasmic reticulum (ER) stress is crucial for inflammation through NF-kB and inflammasome activation. To identify natural flavonoids that regulate ER stress, a DNA microarray was performed using the brains of AD model mice after long-term intake of quercetin, after which the connectivity map (CMap) assay was carried out. We found that luteolin suppresses lipopolysaccharide (LPS)-induced interleukin 1ß (IL1ß) expression by inhibiting ER stress. Immunohistochemical analyses showed that CD68 levels were reduced in the brain after intraperitoneal injection of luteolin in a mouse model of AD, suppressing IL1ß production. As shown by behavioral analyses using the tail suspension test (TST) and forced swimming test (FST), depression-like behaviors were ameliorated in luteolin-treated AD model mice. These findings indicate that luteolin prevents ER stress to suppress microglial activation in the brain, improving individual activity.

Asunto(s)

Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/patología , Conducta Animal , Depresión/tratamiento farmacológico , Depresión/patología , Estrés del Retículo Endoplásmico , Luteolina/uso terapéutico , Envejecimiento/patología , Péptidos beta-Amiloides/metabolismo , Animales , Autofagia/efectos de los fármacos , Modelos Animales de Enfermedad , Estrés del Retículo Endoplásmico/efectos de los fármacos , Células HEK293 , Hipocampo/patología , Humanos , Interleucina-1beta/metabolismo , Lipopolisacáridos , Luteolina/farmacología , Ratones Endogámicos C57BL , Ratones Transgénicos , Microglía/efectos de los fármacos , Microglía/metabolismo

RESUMEN

Quercetin, a type of flavonoid, is believed to reduce age-related cognitive decline. To elucidate its potential function, we carried out a randomized, double-blind, placebo-controlled, parallel-group comparative clinical trial involving 24-week continuous intake of quercetin-rich onion compared to quercetin-free onion as a placebo. Seventy healthy Japanese individuals (aged 60 to 79 years old) were enrolled in this study. We examined the effect of quercetin-rich onion (the active test food) on cognitive function using the Mini-Mental State Examination, Cognitive Assessment for Dementia iPad version, and Neuropsychiatric Inventory Nursing Home version. The Mini-Mental State Examination scores were significantly improved in the active test food group (daily quercetin intake, 50 mg as aglycone equivalent) compared to the placebo food group after 24 weeks. On the Cognitive Assessment for Dementia iPad version for emotional function evaluation, we found that the scores of the active test food group were significantly improved, suggesting that quercetin prevents cognitive decline by improving depressive symptoms and elevating motivation. On the Neuropsychiatric Inventory Nursing Home version, we found significant effects on reducing the burden on study partners. Taking all the data together, we concluded that 24-week continuous intake of quercetin-rich onion reduces age-related cognitive decline, possibly by improving emotional conditions. Clinical trial register and their clinical registration number: This study was registered with UMIN (approval number UMIN000036276, 5 April 2019).

RESUMEN

Apoptotic protease-activating factor 1 (Apaf-1) is a component of apoptosome, which regulates caspase-9 activity. In addition to apoptosis, Apaf-1 plays critical roles in the intra-S-phase checkpoint; therefore, impaired expression of Apaf-1 has been demonstrated in chemotherapy-resistant malignant melanoma and nuclear translocation of Apaf-1 has represented a favorable prognosis of patients with non-small cell lung cancer. In contrast, increased levels of Apaf-1 protein are observed in the brain in Huntington's disease. The regulation of Apaf-1 protein is not yet fully understood. In this study, we show that etoposide triggers the interaction of Apaf-1 with Cullin-4B, resulting in enhanced Apaf-1 ubiquitination. Ubiquitinated Apaf-1, which was degraded in healthy cells, binds p62 and forms aggregates in the cytosol. This complex of ubiquitinated Apaf-1 and p62 induces caspase-9 activation following MG132 treatment of HEK293T cells that stably express bcl-xl. These results show that ubiquitinated Apaf-1 may activate caspase-9 under conditions of proteasome impairment.

Asunto(s)

Factor Apoptótico 1 Activador de Proteasas/metabolismo , Caspasa 9/metabolismo , Proteínas Cullin/metabolismo , Ubiquitinación , Activación Enzimática/efectos de los fármacos , Etopósido/farmacología , Células HEK293 , Humanos , Leupeptinas/farmacología , Unión Proteica/efectos de los fármacos , Ubiquitinación/efectos de los fármacos , Proteína bcl-X/metabolismo

RESUMEN

The initiation of protein synthesis is suppressed under several stress conditions, inducing phosphorylation of the α-subunit of the eukaryotic initiation factor 2 (eIF2α), thereby inactivating the GTP-GDP recycling protein eIF2B. By contrast, the mammalian activating transcription factor 4 (ATF4, also known as cAMP response element binding protein 2 (CREB2)) is still translated under stress conditions. Four protein kinases (general control nonderepressible-2 (GCN2) kinase, double-stranded RNA-activated protein kinase (PKR), PKR-endoplasmic reticulum (ER)-related kinase (PERK), and heme-regulated inhibitor kinase (HRI)) phosphorylate eIF2α in the presence of stressors such as amino acid starvation, viral infection, ER stress, and heme deficiency. This signaling reaction is known as the integrated stress response (ISR). Here, we review ISR signaling in the brain in a mouse model of Alzheimer's disease (AD). We propose that targeting ISR signaling with quercetin has therapeutic potential, because it suppresses amyloid-ß (Aß) production in vitro and prevents cognitive impairments in a mouse model of AD.

Asunto(s)

Memoria/efectos de los fármacos , Quercetina/farmacología , Estrés Fisiológico/efectos de los fármacos , Enfermedad de Alzheimer/fisiopatología , Animales , Humanos , Plasticidad Neuronal/efectos de los fármacos , Transducción de Señal/efectos de los fármacos

RESUMEN

White adipose tissue (eWAT) plays a crucial role in preventing metabolic syndrome. We aimed to investigate WAT distribution and gene expression and lipidomic profiles in epididymal WAT (eWAT) in diet-induced obese mice, reflecting a Western-style diet of humans to elucidate the bioactive properties of the dietary antioxidant curcumin in preventing lifestyle-related diseases. For 16 weeks, we fed C57BL/6J mice with a control diet, a high-fat, high-sucrose and high-cholesterol Western diet or Western diet supplemented with 0.1% (w/w) curcumin. Although the dietary intake of curcumin did not affect eWAT weight or plasma lipid levels, it reduced lipid peroxidation markers' levels in eWAT. Curcumin accumulated in eWAT and changed gene expressions related to eukaryotic translation initiation factor 2 (eIF2) signalling. Curcumin suppressed eIF2α phosphorylation, which is induced by endoplasmic reticulum (ER) stress, macrophage accumulation and nuclear factor-κB (NF-κB) p65 and leptin expression, whereas it's anti-inflammatory effect was inadequate to decrease TNF-α and IFN-γ levels. Lipidomic and gene expression analysis revealed that curcumin decreased some diacylglycerols (DAGs) and DAG-derived glycerophospholipids levels by suppressing the glycerol-3-phosphate acyltransferase 1 and adipose triglyceride lipase expression, which are associated with lipogenesis and lipolysis, respectively. Presumably, these intertwined effects contribute to metabolic syndrome prevention by dietary modification.

Asunto(s)

Tejido Adiposo Blanco/metabolismo , Curcumina/farmacología , Factor 2 Eucariótico de Iniciación/metabolismo , Obesidad/metabolismo , Animales , Antiinflamatorios no Esteroideos/administración & dosificación , Antiinflamatorios no Esteroideos/metabolismo , Antiinflamatorios no Esteroideos/farmacología , Curcumina/administración & dosificación , Curcumina/metabolismo , Dieta Alta en Grasa/efectos adversos , Factor 2 Eucariótico de Iniciación/genética , Expresión Génica/efectos de los fármacos , Perfilación de la Expresión Génica , Humanos , Metabolismo de los Lípidos/efectos de los fármacos , Metabolismo de los Lípidos/genética , Masculino , Ratones Endogámicos C57BL , Obesidad/etiología , Obesidad/genética , Transducción de Señal/efectos de los fármacos

RESUMEN

Olfaxin, which is a BNIP2 and Cdc42GAP homology (BCH) domain-containing protein, is predominantly expressed in mitral and tufted (M/T) cells in the olfactory bulb (OB). Olfaxin and Caytaxin, which share 56.3% amino acid identity, are similar in their glutamatergic terminal localization, kidney-type glutaminase (KGA) interaction, and caspase-3 substrate. Although the deletion of Caytaxin protein causes human Cayman ataxia and ataxia in the mutant mouse, the function of Olfaxin is largely unknown. In this study, we generated Prune2 gene mutant mice (Prune2Ex16-/-; knock out [KO] mice) using the CRISPR/Cas9 system, during which the exon 16 containing start codon of Olfaxin mRNA was deleted. Exon 16 has 80 nucleotides and is contained in four of five Prune2 isoforms, including PRUNE2, BMCC1, BNIPXL, and Olfaxin/BMCC1s. The levels of Olfaxin mRNA and Olfaxin protein in the OB and piriform cortex of KO mice significantly decreased. Although Prune2 mRNA also significantly decreased in the spinal cord, the gross anatomy of the spinal cord and dorsal root ganglion (DRG) was intact. Further, disturbance of the sensory and motor system was not observed in KO mice. Therefore, in the current study, we examined the role of Olfaxin in the olfactory system where PRUNE2, BMCC1, and BNIPXL are scarcely expressed. Odor preference was impaired in KO mice using opposite-sex urinary scents as well as a non-social odor stimulus (almond). Results of the odor-aversion test demonstrated that odor-associative learning was disrupted in KO mice. Moreover, the NMDAR2A/NMDAR2B subunits switch in the piriform cortex was not observed in KO mice. These results indicated that Olfaxin may play a critical role in odor preference and olfactory memory.

Asunto(s)

Encéfalo/metabolismo , Proteínas de Neoplasias/fisiología , Percepción Olfatoria/fisiología , Olfato , Animales , Aprendizaje por Asociación/fisiología , Cerebelo/metabolismo , Exones , Femenino , Masculino , Ratones Noqueados , Proteínas de Neoplasias/genética , Odorantes , Bulbo Olfatorio/metabolismo , Corteza Piriforme/metabolismo , Isoformas de Proteínas/metabolismo , ARN Mensajero , Receptores de N-Metil-D-Aspartato/metabolismo

RESUMEN

Patients with Alzheimer's disease (AD) experience a wide array of cognitive deficits, which typically include the impairment of explicit memory. In previous studies, the authors reported that a flavonoid, quercetin, reduces the expression of ATF4 and delays memory deterioration in an early-stage AD mouse model. In the present study, the effects of long-term quercetin intake on memory recall were assessed using contextual fear conditioning in aged wild-type mice. In addition, the present study examined whether memory recall was affected by the intake of quercetin-rich onion (a new cultivar of hybrid onion 'Quergold') powder in early-stage AD patients. In-vivo analysis indicated that memory recall was enhanced in aged mice fed a quercetin-containing diet. Memory recall in early-stage AD patients, determined using the Revised Hasegawa Dementia Scale, was significantly improved by the intake of quercetin-rich onion (Quergold) powder for 4 weeks compared with the intake of control onion ('Mashiro' white onion) powder. These results indicate that quercetin might influence memory recall.

Asunto(s)

Antioxidantes/uso terapéutico , Condicionamiento Psicológico/efectos de los fármacos , Miedo/efectos de los fármacos , Trastornos de la Memoria/tratamiento farmacológico , Quercetina/uso terapéutico , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/complicaciones , Enfermedad de Alzheimer/diagnóstico por imagen , Compuestos de Anilina , Animales , Benzotiazoles/farmacocinética , Femenino , Humanos , Yofetamina/farmacocinética , Imagen por Resonancia Magnética , Masculino , Trastornos de la Memoria/diagnóstico por imagen , Trastornos de la Memoria/etiología , Recuerdo Mental/efectos de los fármacos , Pruebas de Estado Mental y Demencia , Ratones , Ratones Endogámicos C57BL , Pruebas Neuropsicológicas , Tomografía de Emisión de Positrones , Tiazoles

RESUMEN

The endoplasmic reticulum (ER) is important in various cellular functions, such as secretary and membrane protein biosynthesis, lipid synthesis, and calcium storage. ER stress, including membrane distortion, is associated with many diseases such as Huntington's disease. In particular, nuclear envelope distortion is related to neuronal cell death associated with polyglutamine. However, the mechanism by which polyglutamine causes ER membrane distortion remains unclear. We used electron microscopy, fluorescence protease protection assay, and alkaline treatment to analyze the localization of polyglutamine in cells. We characterized polyglutamine embedded in the ER membrane and noted an effect on morphology, including the dilation of ER luminal space and elongation of ER-mitochondria contact sites, in addition to the distortion of the nuclear envelope. The polyglutamine embedded in the ER membrane was observed at the same time as Bax insertion. These results demonstrated that the ER membrane may be a target of polyglutamine, which triggers cell death through Bax.

Asunto(s)

Membrana Celular/fisiología , Membrana Celular/ultraestructura , Retículo Endoplásmico/fisiología , Fluidez de la Membrana/fisiología , Péptidos/metabolismo , Proteína X Asociada a bcl-2/metabolismo , Células HEK293 , Humanos

RESUMEN

Cell death abnormal (ced)-3 and ced-4 genes regulate apoptosis to maintain tissue homeostasis in Caenorhabditis elegans. Apoptosome formation and CED-4 translocation drive CED-3 activation. However, the precise role of CED-4 translocation is not yet fully understood. In this study, using a combination of immunoprecipitation and reverse transcription-polymerase chain reaction methods in cells and a glutathione-S-transferase pull down assay in a cell-free system, we show that CED-4 binds ced-3 mRNA. In the presence of ced-3 mRNA, CED-4 protein is enriched in the microsomal fraction and interacts with ribosomal protein L10a in mammalian cells, increasing the levels of CED-3. These results suggest that CED-4 forms a complex with ced-3 mRNA and delivers it to ribosomes for translation.

Asunto(s)

Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Unión al Calcio/genética , Proteínas de Unión al Calcio/metabolismo , Caspasas/genética , Caspasas/metabolismo , MicroARNs/metabolismo , Ribosomas/metabolismo , Regulación de la Expresión Génica/fisiología , Células HEK293 , Humanos , MicroARNs/genética , Transporte de Proteínas/fisiología , ARN Mensajero , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo

RESUMEN

The production of amyloid ß (Aß) in the brain from Aß precursor protein (APP) through γ-secretase is important for the pathogenesis of Alzheimer's disease (AD). Our previous studies have demonstrated that autophagy impairment and endoplasmic reticulum stress increase presenilin 1 expression and enhance γ-secretase activity through the phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) and the translation of activating transcription factor 4 (ATF4). However, the inhibitory molecules for γ-secretase are largely unknown. Here, we demonstrate that the levels of ATF4 expression are increased in the brain of APP23 AD model mice; furthermore, these levels enhanced in the brain of APP23 mice crossed with obese and diabetic db/db (Lepr(db/db)) mice. A polyhydroxylated flavonoid, quercetin, suppressed presenilin 1 expression and Aß secretion in autophagy-impaired cells by the induction of growth arrest and DNA damaged-inducible gene (GADD) 34, which mediates eIF2α dephosphorylation, leading to decreased ATF4 expression. GADD34 induction was observed in the brain of wild-type mice, and APP23 mice fed quercetin in their diet. After the long-term feeding of quercetin, deterioration in memory assessed by freezing behavior was delayed in APP23 mice. These results indicate that quercetin may reduce eIF2α phosphorylation and ATF4 expression through GADD34 induction in the brain, leading to the improvement of memory in aged mice and the delay of deterioration in memory at the early stage of AD in AD model mice.

Asunto(s)

Enfermedad de Alzheimer/tratamiento farmacológico , Antioxidantes/farmacología , Proteínas de Unión al ADN/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Proteína Fosfatasa 1/metabolismo , Quercetina/farmacología , Factores de Transcripción/metabolismo , Factor de Transcripción Activador 4/metabolismo , Enfermedad de Alzheimer/complicaciones , Enfermedad de Alzheimer/genética , Péptidos beta-Amiloides/genética , Péptidos beta-Amiloides/metabolismo , Péptidos beta-Amiloides/farmacología , Precursor de Proteína beta-Amiloide/genética , Animales , Antioxidantes/uso terapéutico , Proteína 5 Relacionada con la Autofagia , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Condicionamiento Clásico/efectos de los fármacos , Modelos Animales de Enfermedad , Regulación de la Expresión Génica/genética , Células HEK293 , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Proteínas Asociadas a Microtúbulos/metabolismo , Fragmentos de Péptidos/farmacología , Fosforilación/efectos de los fármacos , Presenilina-1/metabolismo , Quercetina/uso terapéutico , Receptores de Leptina/genética , Receptores de Leptina/metabolismo

RESUMEN

The endoplasmic reticulum (ER) plays a pivotal role in cellular functions such as the ER stress response. However, the effect of the ER membrane on caspase activation remains unclear. This study reveals that polyglutamine oligomers augmented at ER induce insertion of Bax into the ER membrane, thereby activating caspase-7. In line with the role of ER in cell death induced by polyglutamine expansion, the ER membrane was found to be disrupted and dilated in the brain of a murine model of Huntington's disease. We can conclude that polyglutamine expansion may drive caspase-7 activation by disrupting the ER membrane.

Asunto(s)

Caspasa 7/metabolismo , Retículo Endoplásmico/metabolismo , Enfermedad de Huntington/metabolismo , Péptidos/metabolismo , Proteína X Asociada a bcl-2/metabolismo , Animales , Apoptosis , Encéfalo/metabolismo , Encéfalo/patología , Modelos Animales de Enfermedad , Retículo Endoplásmico/patología , Activación Enzimática , Células HEK293 , Humanos , Proteína Huntingtina , Enfermedad de Huntington/genética , Enfermedad de Huntington/patología , Membranas Intracelulares/metabolismo , Membranas Intracelulares/patología , Ratones , Ratones Transgénicos , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo

RESUMEN

The gamma (γ)-secretase holoenzyme is composed of four core proteins and cleaves APP to generate amyloid beta (Aß), a key molecule that causes major neurotoxicity during the early stage of Alzheimer's disease (AD). However, despite its important role in Aß production, little is known about the regulation of γ-secretase. OCIAD2, a novel modulator of γ-secretase that stimulates Aß production, and which was isolated from a genome-wide functional screen using cell-based assays and a cDNA library comprising 6,178 genes. Ectopic expression of OCIAD2 enhanced Aß production, while reduction of OCIAD2 expression suppressed it. OCIAD2 expression facilitated the formation of an active γ-secretase complex and enhanced subcellular localization of the enzyme components to lipid rafts. OCIAD2 interacted with nicastrin to stimulate γ-secretase activity. OCIAD2 also increased the interaction of nicastrin with C99 and stimulated APP processing via γ-secretase activation, but did not affect Notch processing. In addition, a cell-permeable Tat-OCIAD2 peptide that interfered with the interaction of OCIAD2 with nicastrin interrupted the γ-secretase-mediated AICD production. Finally, OCIAD2 expression was significantly elevated in the brain of AD patients and PDAPP mice. This study identifies OCIAD2 as a selective activator of γ-secretase to increase Aß generation.

Asunto(s)

Enfermedad de Alzheimer/genética , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas de Neoplasias/metabolismo , Enfermedad de Alzheimer/etiología , Enfermedad de Alzheimer/metabolismo , Secretasas de la Proteína Precursora del Amiloide/química , Secretasas de la Proteína Precursora del Amiloide/genética , Péptidos beta-Amiloides/biosíntesis , Animales , Fibroblastos/metabolismo , Biblioteca de Genes , Humanos , Glicoproteínas de Membrana/genética , Microdominios de Membrana/metabolismo , Ratones , Ratones Noqueados/metabolismo , Proteínas de Neoplasias/genética , Receptores Notch/metabolismo

RESUMEN

Four Bacillus subtilis strains were isolated from traditional fermented foods, and the sequences of their extracellular alkaline proteases (AprE) were analyzed and cloned. The recombinant enzymes synthesized by means of Escherichia coli exhibited high proteolytic activity. AprE CN2 showed hydrolytic activity 4-fold higher than that of AprE 168. This activity was also seen in the presence of relatively high NaCl concentrations.

Asunto(s)

Bacillus subtilis/enzimología , Bacillus subtilis/genética , Proteínas Bacterianas/genética , Endopeptidasas/genética , Espacio Extracelular/enzimología , Análisis de Secuencia , Secuencia de Aminoácidos , Bacillus subtilis/citología , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Clonación Molecular , Endopeptidasas/química , Endopeptidasas/metabolismo , Cinética , Datos de Secuencia Molecular , Cloruro de Sodio/farmacología

RESUMEN

Prune homolog 2 (Drosophila) (PRUNE2) encodes a BCH motif-containing protein that shares homology with the Cayman ataxia-related protein Caytaxin. Caytaxin is a substrate of caspase-3 and is specifically expressed at the presynapse of vesicular-type glutamate transporter (VGLUT)-positive neurons, where it plays a role in glutamate neurotransmission primarily in the cerebellum and hippocampus. Here, we showed that a novel Prune2 isoform contains a BCH motif and localizes predominantly to the synaptic cytosol, similar to Caytaxin. However, the isoform is expressed predominantly in the olfactory bulb and layer Ia of the piriform cortex, where Caytaxin is scarcely expressed. The isoform expression is upregulated during development, similar to that in the presynaptic-localizing proteins Synapsin I and Bassoon. Prune2 and its previously identified isoforms have been shown to be a susceptibility gene for Alzheimer's disease, a biomarker for leiomyosarcomas, a proapoptotic protein, and an antagonist of cellular transformation. In addition, a novel isoform may develop new roles for Prune2 at the synapse in olfactory systems.

Asunto(s)

Proteínas de Neoplasias/genética , Bulbo Olfatorio/fisiología , Vías Olfatorias/fisiología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Citosol/metabolismo , Estriol/análogos & derivados , Estriol/metabolismo , Exones/genética , Células HEK293 , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Datos de Secuencia Molecular , Proteínas de Neoplasias/química , Proteínas de Neoplasias/metabolismo , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Estructura Terciaria de Proteína/fisiología

RESUMEN

The endoplasmic reticulum (ER) copes with unfolded proteins in the lumen (ER stress) by activating three distinct intracellular signaling pathways of unfolded protein response (UPR). ER stress contributes to the pathogenesis of obesity and diabetes, which are risk factors for Alzheimer's disease (AD) that accelerate the pathogenesis of AD. However, whether ER stress is involved in the development of AD remains unclear. In this study, we demonstrate that ER stress induces presenilin-1 expression through activating transcription factor 4 (ATF4), resulting in increased amyloid-ß (Aß) secretion by γ-secretase activity, which is suppressed by quercetin by modifying UPR signaling. This result suggests that ER stress may be stimulated in obesity and type 2 diabetes, thereby enhancing γ-secretase activity that is the underlying molecular mechanism affecting the pathogenesis of AD.

Asunto(s)

Secretasas de la Proteína Precursora del Amiloide/biosíntesis , Estrés del Retículo Endoplásmico/fisiología , Retículo Endoplásmico/enzimología , Factor de Transcripción Activador 4/antagonistas & inhibidores , Factor de Transcripción Activador 4/metabolismo , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Animales , Estrés del Retículo Endoplásmico/efectos de los fármacos , Estrés del Retículo Endoplásmico/genética , Regulación de la Expresión Génica , Células HEK293 , Humanos , Ratones , Ratones Endogámicos C57BL , Quercetina/farmacología , Receptor Notch1/metabolismo

RESUMEN

A family of Bcl-2/adenovirus E1B 19kDa-interacting proteins (BNIPs) plays critical roles in several cellular processes such as cellular transformation, apoptosis, neuronal differentiation, and synaptic function, which are mediated by the BNIP2 and Cdc42GAP homology (BCH) domain. Prune homolog 2 (Drosophila) (PRUNE2) and its isoforms -C9orf65, BCH motif-containing molecule at the carboxyl terminal region 1 (BMCC1), and BNIP2 Extra Long (BNIPXL) - have been shown to be a susceptibility gene for Alzheimer's disease, a biomarker for leiomyosarcomas, a proapoptotic protein in neuronal cells, and an antagonist of cellular transformation, respectively. However, precise localization of PRUNE2 in the brain remains unclear. Here, we identified the distribution of Prune2 mRNA in the adult mouse brain. Prune2 mRNA is predominantly expressed in the neurons of the cranial nerve motor nuclei and the motor neurons of the spinal cord. The expression in the dorsal root ganglia (DRG) is consistent with the previously described reports. In addition, we observed the expression in another sensory neuron in the mesencephalic trigeminal nucleus. These results suggest that Prune2 may be functional in these restricted brain regions.

Asunto(s)

Sistema Nervioso Central/metabolismo , Proteínas de Neoplasias/biosíntesis , ARN Mensajero/biosíntesis , Animales , Secuencia de Bases , Química Encefálica/genética , Colina O-Acetiltransferasa/metabolismo , Nervios Craneales/enzimología , Nervios Craneales/metabolismo , Bases de Datos Factuales , Exones/genética , Técnica del Anticuerpo Fluorescente , Ganglios Espinales/enzimología , Ganglios Espinales/crecimiento & desarrollo , Regulación del Desarrollo de la Expresión Génica , Humanos , Hibridación in Situ , Ratones , Ratones Endogámicos C57BL , Neuronas Motoras/enzimología , Proteínas de Neoplasias/genética , ARN Mensajero/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Células Receptoras Sensoriales/enzimología , Médula Espinal/enzimología , Núcleos del Trigémino/enzimología

RESUMEN

Caspase plays an important role in apoptosis and physiological processes such as synaptic plasticity. However, the caspase substrate at the synapse is still unknown. Here we used an in vitro cleavage assay with a small-pool human brain cDNA library. We identified the presynaptic protein Caytaxin as a substrate of caspase-3 and caspase-7. Deficiency in Caytaxin causes Cayman ataxia, a disorder characterized by cerebellar dysfunction and mental retardation. Caytaxin cleavage in cerebellar granule neurons is dependent on caspase-3 activation. The cleavage site is upstream of the cellular retinal and the TRIO guanine exchange factor domain, producing a C-terminal fragment that may play an alternative role in inhibiting MEK2 signaling. Thus, we concluded that Caytaxin is a novel substrate of caspase-3 at the presynapse.

Asunto(s)

Caspasa 3/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Secuencia de Aminoácidos , Animales , Caspasa 7/metabolismo , Línea Celular , Humanos , MAP Quinasa Quinasa 2/fisiología , Ratones , Datos de Secuencia Molecular , Alineación de Secuencia , Transducción de Señal , Sinapsis/metabolismo