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1.
Chemistry ; 28(16): e202104627, 2022 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-35137978

RESUMEN

The silver-promoted reaction of tertiary cyclobutanols with N-methoxypyridinium salts enables the efficient synthesis of a range of C2-substituted pyridines. The overall process likely occurs by ring-opening (via ß-scission) of the cyclobutoxy radical to generate the corresponding γ-keto alkyl radical that itself adds to the pyridinium salt. A wide range of tertiary cyclobutanols and N-methoxypyridinium salts are compatible with the reaction conditions.


Asunto(s)
Ciclobutanos , Compuestos de Piridinio , Sales (Química) , Plata
2.
J Org Chem ; 84(11): 6557-6564, 2019 06 07.
Artículo en Inglés | MEDLINE | ID: mdl-31090405

RESUMEN

The efficient and practical nucleophilic cyanation and trifluoromethylation with appropriate trimethylsilyl nucleophiles were developed. Catalytic amounts of cheap and nontoxic Cs2CO3 were used to maintain a sufficiently high concentration of nucleophilic anion (CN- or CF3-) which could begin the catalytic cycle. The present methodologies provide diverse functionalized monofluoroalkenes bearing a cyano and trifluoromethyl group with excellent to moderate stereoselectivities.

3.
J Biol Chem ; 287(4): 2364-77, 2012 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-22123824

RESUMEN

Previous studies in our laboratory have shown that mixed lineage kinase 3 (MLK3) can be activated following global ischemia. In addition, other laboratories have reported that the activation of MLK3 may be linked to the accumulation of free radicals. However, the mechanism of MLK3 activation remains incompletely understood. We report here that MLK3, overexpressed in HEK293 cells, is S-nitrosylated (forming SNO-MLK3) via a reaction with S-nitrosoglutathione, an exogenous nitric oxide (NO) donor, at one critical cysteine residue (Cys-688). We further show that the S-nitrosylation of MLK3 contributes to its dimerization and activation. We also investigated whether the activation of MLK3 is associated with S-nitrosylation following rat brain ischemia/reperfusion. Our results show that the administration of 7-nitroindazole, an inhibitor of neuronal NO synthase (nNOS), or nNOS antisense oligodeoxynucleotides diminished the S-nitrosylation of MLK3 and inhibited its activation induced by cerebral ischemia/reperfusion. In contrast, 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (an inhibitor of inducible NO synthase) or nNOS missense oligodeoxynucleotides did not affect the S-nitrosylation of MLK3. In addition, treatment with sodium nitroprusside (an exogenous NO donor) and S-nitrosoglutathione or MK801, an antagonist of the N-methyl-D-aspartate receptor, also diminished the S-nitrosylation and activation of MLK3 induced by cerebral ischemia/reperfusion. The activation of MLK3 facilitated its downstream protein kinase kinase 4/7 (MKK4/7)-JNK signaling module and both nuclear and non-nuclear apoptosis pathways. These data suggest that the activation of MLK3 during the early stages of ischemia/reperfusion is modulated by S-nitrosylation and provides a potential new approach for stroke therapy whereby the post-translational modification machinery is targeted.


Asunto(s)
Isquemia Encefálica/enzimología , Quinasas Quinasa Quinasa PAM/metabolismo , Multimerización de Proteína , Procesamiento Proteico-Postraduccional , Animales , Isquemia Encefálica/genética , Isquemia Encefálica/patología , Maleato de Dizocilpina/farmacología , Activación Enzimática/efectos de los fármacos , Activación Enzimática/genética , Inhibidores Enzimáticos/farmacología , Células HEK293 , Humanos , Quinasas Quinasa Quinasa PAM/genética , Masculino , Fármacos Neuroprotectores/farmacología , Óxido Nítrico Sintasa de Tipo I/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo I/genética , Óxido Nítrico Sintasa de Tipo I/metabolismo , Oligodesoxirribonucleótidos Antisentido/farmacología , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/enzimología , Daño por Reperfusión/genética , Daño por Reperfusión/patología , S-Nitrosoglutatión/metabolismo , Tiazinas/farmacología , Proteina Quinasa Quinasa Quinasa 11 Activada por Mitógeno
4.
Chem Commun (Camb) ; 59(50): 7831-7834, 2023 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-37272849

RESUMEN

Copper-catalyzed asymmetric dearomative azidation of tryptamines using azidobenziodoxolone as an azidating reagent was developed, which affords a variety of 3a-azido-pyrroloindolines in good to high enantioselectivities under mild reaction conditions. The azides could be readily transformed into the corresponding 3a-amino-pyrroloindolines via reduction and 1,2,3-triazole derivatives via a click reaction.

5.
J Biol Chem ; 286(9): 7669-80, 2011 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-21148565

RESUMEN

We previously showed that Bcl-2 (B-cell lymphoma 2) is down-regulated in a kainate (KA)-induced rat epileptic seizure model. The underlying mechanism had remained largely unknown, but we here report for the first time that denitrosylation and ubiquitination are involved. Our results show that the S-nitrosylation levels of Bcl-2 are down-regulated after KA injection and that the GluR6 (glutamate receptor 6) antagonist NS102 can inhibit the denitrosylation of Bcl-2. Moreover, the ubiquitin-dependent degradation of Bcl-2 was found to be promoted after KA treatment, which could be suppressed by the proteasome inhibitor MG132 and the NO donors, sodium nitroprusside and S-nitrosoglutathione. In addition, experiments based on siRNA transfections were performed in the human SH-SY5Y neuroblastoma cell line to verify that the stability of Bcl-2 is causal to neuronal survival. At the same time, it was found that the exogenous NO donor GSNO could protect neurons when Bcl-2 is targeted. Subsequently, these mechanisms were morphologically validated by immunohistochemistry, cresyl violet staining, and in situ TUNEL staining to analyze the expression of Bcl-2 as well as the survival of CA1 and CA3/DG pyramidal neurons. NS102, GSNO, sodium nitroprusside, and MG132 contribute to the survival of CA1 and CA3/DG pyramidal neurons by attenuating Bcl-2 denitrosylation. Taken together, our data reveal that Bcl-2 ubiquitin-dependent degradation is induced by Bcl-2 denitrosylation during neuronal apoptosis after KA treatment.


Asunto(s)
Epilepsia/metabolismo , Hipocampo/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Receptores de Ácido Kaínico/metabolismo , Ubiquitina/metabolismo , Animales , Isquemia Encefálica/inducido químicamente , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , Región CA1 Hipocampal/efectos de los fármacos , Región CA1 Hipocampal/metabolismo , Región CA1 Hipocampal/patología , Región CA3 Hipocampal/efectos de los fármacos , Región CA3 Hipocampal/metabolismo , Región CA3 Hipocampal/patología , Caspasa 3/metabolismo , Línea Celular Tumoral , Giro Dentado/efectos de los fármacos , Giro Dentado/metabolismo , Giro Dentado/patología , Modelos Animales de Enfermedad , Epilepsia/inducido químicamente , Epilepsia/patología , Agonistas de Aminoácidos Excitadores/toxicidad , Hipocampo/efectos de los fármacos , Hipocampo/patología , Humanos , Ácido Kaínico/toxicidad , Masculino , Neuroblastoma , Óxido Nítrico/metabolismo , Donantes de Óxido Nítrico/farmacología , Nitrógeno/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Inhibidores de Proteasoma , Procesamiento Proteico-Postraduccional/fisiología , Ratas , Ratas Sprague-Dawley , Receptores de Ácido Kaínico/genética , Receptor de Ácido Kaínico GluK2
6.
Biochem Biophys Res Commun ; 420(3): 594-9, 2012 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-22445759

RESUMEN

Glutamate receptor 6 (GluR6) is well documented to play a pivotal role in ischemic brain injury, which is mediated by the GluR6·PSD95·MLK3 signaling module and subsequent c-Jun N-terminal kinase (JNK) activation. Our recent studies show that GluR6 is S-nitrosylated in the early stages of ischemia-reperfusion. NO (Nitric Oxide) is mainly generated from neuronal nitric oxide synthase (nNOS) in cerebral neurons during the early stages of reperfusion. Here, the effect of nNOS downregulation on GluR6 S-nitrosylation and GluR6-mediated signaling was investigated in cerebral ischemia and reperfusion. Administration of nNOS oligonucleotides confirmed that GluR6 nitrosylation is induced by nNOS-derived endogenous NO and further activates the GluR6·PSD95·MLK3 signaling module and JNK signaling pathway. Moreover, this study revealed for the first time that nNOS can bind with GluR6 during ischemic reperfusion, and PSD95 is involved in this interaction. In summary, our results suggest that nNOS binds with GluR6 via PSD95 and then produces endogenous NO to S-nitrosylate GluR6 in cerebral ischemia-reperfusion, which provides a new approach for stroke therapy.


Asunto(s)
Apoptosis , Isquemia Encefálica/patología , Neuronas/patología , Óxido Nítrico Sintasa de Tipo I/metabolismo , Receptores de Ácido Kaínico/metabolismo , Animales , Isquemia Encefálica/metabolismo , Región CA1 Hipocampal , Regulación hacia Abajo , Técnicas de Silenciamiento del Gen , Masculino , Neuronas/metabolismo , Nitratos/metabolismo , Óxido Nítrico Sintasa de Tipo I/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo I/genética , Fosforilación , Proteínas Proto-Oncogénicas c-jun/metabolismo , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/metabolismo , Daño por Reperfusión/patología , Receptor de Ácido Kaínico GluK2
7.
Mol Cell Biochem ; 365(1-2): 363-77, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22422045

RESUMEN

Previous studies suggested that activated c-Src promote the tyrosine phosphorylation of NMDA receptor subunit NR2A, and thus aggravate the injury induced by transient cerebral ischemia/reperfusion (I/R) in rat hippocampus CA1 region. In this study, we examined the effect of nitric oxide (NO) on the activation of c-Src and the tyrosine phosphorylation of NMDA receptor NR2A subunit. The results show that S-nitrosylation and the phosphorylation of c-Src were induced after cerebral I/R in rats, and administration of nNOS inhibitor 7-NI, nNOS antisense oligonucleotides and exogenous NO donor sodium nitroprusside diminished the increased S-nitrosylation and phosphorylation of c-Src during cerebral I/R. The cysteine residues of c-Src modified by S-nitrosylation are Cys489, Cys498, and Cys500. On the other hand, NMDAR antagonist MK-801 could attenuate the S-nitrosylation and activation of c-Src. Taken together, the S-nitrosylation of c-Src is provoked by NO derived from endogenous nNOS, which is activated by Ca(2+) influx from NMDA receptors, and promotes the auto-phosphorylation at tyrosines and further phosphorylates NR2A. The molecular mechanism we outlined here is a novel postsynaptic NMDAR-nNOS/c-Src-mediated signaling amplification, the 'NMDAR-nNOS â†’ NO â†’ SNO-c-Src â†’ p-c-Src â†’ NMDAR-nNOS' cycle, which presents the possibility as a potential therapeutic target for stroke treatment.


Asunto(s)
Isquemia Encefálica/enzimología , Activación Enzimática , Óxido Nítrico Sintasa de Tipo I/metabolismo , Procesamiento Proteico-Postraduccional , Receptores de N-Metil-D-Aspartato/metabolismo , Daño por Reperfusión/enzimología , Familia-src Quinasas/metabolismo , Secuencias de Aminoácidos , Animales , Apoptosis , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , Cisteína/metabolismo , Maleato de Dizocilpina/farmacología , Células HEK293 , Hipocampo/irrigación sanguínea , Hipocampo/efectos de los fármacos , Hipocampo/enzimología , Hipocampo/patología , Humanos , Indazoles/farmacología , Masculino , Fármacos Neuroprotectores/farmacología , Donantes de Óxido Nítrico/farmacología , Óxido Nítrico Sintasa de Tipo I/antagonistas & inhibidores , Nitroprusiato/farmacología , Fosforilación , Estructura Terciaria de Proteína , Ratas , Ratas Sprague-Dawley , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Daño por Reperfusión/metabolismo , Daño por Reperfusión/patología , S-Nitrosoglutatión/farmacología , Familia-src Quinasas/química
8.
Biochemistry (Mosc) ; 77(6): 671-8, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22817468

RESUMEN

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a glycolytic enzyme, plays an important role in glycolysis. It was reported that GAPDH undergoes S-nitrosylation, which facilitated its binding to Siah1 and resulted in nuclear translocation and cell apoptosis. The results of this study show that GAPDH S-nitrosylation, Siah1 binding, translocation to nucleus, and concomitant neuron death occur during the early stages of reperfusion in the rat four-vessel occlusion ischemic model. N-Methyl-D-aspartate receptor antagonist MK801, neuronal nitric oxide synthase inhibitor 7-nitroindazole, or monoamine oxidase-B inhibitor (R)-(-)-deprenyl hydrochloride could inhibit GAPDH S-nitrosylation and translocation and exert neuroprotective effects.


Asunto(s)
Isquemia Encefálica/metabolismo , Inhibidores Enzimáticos/farmacología , Gliceraldehído-3-Fosfato Deshidrogenasas/metabolismo , Fármacos Neuroprotectores/farmacología , Daño por Reperfusión/metabolismo , Transporte Activo de Núcleo Celular/efectos de los fármacos , Análisis de Varianza , Animales , Apoptosis/efectos de los fármacos , Región CA1 Hipocampal/efectos de los fármacos , Núcleo Celular/enzimología , Maleato de Dizocilpina/farmacología , Gliceraldehído-3-Fosfato Deshidrogenasas/química , Humanos , Indazoles/farmacología , Masculino , Monoaminooxidasa/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa de Tipo I/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo I/metabolismo , Compuestos Nitrosos/química , Proteínas Nucleares/metabolismo , Células Piramidales/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Selegilina/farmacología , Ubiquitina-Proteína Ligasas/metabolismo , Vitamina B 12/análogos & derivados , Vitamina B 12/química
9.
J Recept Signal Transduct Res ; 31(4): 307-13, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21726169

RESUMEN

It is demonstrated that the c-Jun N-terminal kinase (JNK) signaling pathway plays a critical role in ischemic brain injury. Our previous studies have suggested that K252a can obviously inhibit JNK activation induced by ischemia/reperfusion in the vulnerable hippocampal CA1 subregion. Here, we further discussed the potential mechanism of ischemic brain injury induced by the activation of JNK after 15?min of transient global cerebral ischemia. As a result, through inhibiting phosphorylation of Bcl-2 (a cytosolic target of JNK) and 14-3-3 protein (a cytoplasmic anchor of Bax) induced by the activation of JNK, K252a decreased the release of Bax from Bcl-2/Bax and 14-3-3/Bax dimers, further attenuating the translocation of Bax from cytosol to mitochondria and the release of cytochrome c induced by ischemia/reperfusion, which related to mitochondria-mediated apoptosis. Importantly, pre-infusion of K2525a 20?min before ischemia showed neuroprotective effect against neuronal cells apoptosis. These findings imply that K252a induced neuroprotection against ischemia/reperfusion in rat hippocampal CA1 subregion via inhibiting the mitochondrial apoptosis pathway induced by JNK activation.


Asunto(s)
Apoptosis/efectos de los fármacos , Isquemia Encefálica/metabolismo , Carbazoles/farmacología , Alcaloides Indólicos/farmacología , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Quinasas Quinasa Quinasa PAM/metabolismo , Mitocondrias/metabolismo , Neuronas/efectos de los fármacos , Proteína X Asociada a bcl-2/metabolismo , Proteínas 14-3-3/metabolismo , Animales , Isquemia Encefálica/patología , Región CA1 Hipocampal/citología , Región CA1 Hipocampal/patología , Región CA1 Hipocampal/fisiopatología , Citocromos c/metabolismo , Inhibidores Enzimáticos/farmacología , Proteínas Quinasas JNK Activadas por Mitógenos/antagonistas & inhibidores , Masculino , Neuronas/citología , Neuronas/fisiología , Fármacos Neuroprotectores/farmacología , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Ratas , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos , Proteina Quinasa Quinasa Quinasa 11 Activada por Mitógeno
10.
Arch Biochem Biophys ; 515(1-2): 89-98, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21843499

RESUMEN

Previous studies have shown that the death-associated protein (Daxx) shuttles between nucleus and cytoplasm under ischemic stress, and the subcellular localization of Daxx plays an important role in ischemic neuron death. In this study, by blocking the Daxx trafficking, the rat hippocampus CA1 neurons were protected against cerebral ischemia/reperfusion, and the molecular mechanism underlying this neuroprotection was studied. We found that pretreatment of SP600125, an inhibitor of c-Jun N-terminal kinase (JNK), or an anti-oxidant, N-acetylcysteine (NAC), could not only prevent Daxx from trafficking but also increase the number of the surviving CA1 pyramidal cells of hippocampus at 5days of reperfusion. Furthermore, knock-down of endogenous Daxx exerted similar neuroprotective effect during ischemia/reperfusion. We found the treatment of SP600125 or NAC could decrease the activation of Ask1 during ischemia/reperfusion and suppress the assembly of the Fas·Daxx·Ask1 signaling module, and in succession inhibit JNK activation and c-Jun phosphorylation. This study provides the Daxx trafficking as a new potential therapeutic target for ischemic brain injury.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Muerte Celular , Proteínas Nucleares/metabolismo , Animales , Secuencia de Bases , Cartilla de ADN , Masculino , Chaperonas Moleculares , Transporte de Proteínas , Ratas , Ratas Sprague-Dawley
11.
Can J Neurol Sci ; 38(6): 880-6, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22030427

RESUMEN

BACKGROUND: Cytosol Ca2+ overload plays a vital role in ischemic neuronal damage, which is largely contributed by the Ca2+ influx through L-type voltage-gated calcium channels (L-VGCCs) and N-methyl-D-aspartate (NMDA) type glutamate receptors. In this article, L-VGCCs were activated by depolarization to investigate the cross-talk between NMDA receptors and L-VGCCs. METHODS: Depolarization was induced by 20 minutes incubation of 75 mM KCl in cultured rat cortical neuron. Apoptosis-like neuronal death was detected by DAPI staining. Tyrosine phosphorylation of NMDA receptor subunit 2A (NR2A), interactions of Src and NR2A were detected by immunoblot and immunoprecipitation. RESULTS: Depolarization induced cortical neuron apoptosis-like cell death after 24 hours of restoration. The apoptosis was partially inhibited by 5 mM EGTA, 100 µM Cd2+, 10 µM nimodipine, 100 µM genistein, 20 µM MK-801, 2 µM PP2 and combined treatment of nimodipine and MK-801. NR2A tyrosine phosphorylation increased after depolarization, and the increase was inhibited by the drugs listed above. Moreover, non-receptor tyrosine kinase Src bound with NR2A after depolarization and restoration. The binding was also inhibited by the drugs listed above. CONCLUSIONS: The results indicated that depolarization-induced neuronal death might be due to extracellular Ca2+ influx through L-VGCCs and subsequently Src activationmediated NR2A tyrosine phosphorylation.


Asunto(s)
Apoptosis/fisiología , Corteza Cerebral/citología , Neuronas/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Tirosina/metabolismo , Animales , Apoptosis/efectos de los fármacos , Bloqueadores de los Canales de Calcio/farmacología , Células Cultivadas , Maleato de Dizocilpina/farmacología , Embrión de Mamíferos , Inhibidores Enzimáticos/farmacología , Antagonistas de Aminoácidos Excitadores/farmacología , Inmunoprecipitación , Indoles , Isoflavonas/farmacología , Neuronas/efectos de los fármacos , Nimodipina/farmacología , Fosforilación/efectos de los fármacos , Cloruro de Potasio/farmacología , Pirimidinas/farmacología , Ratas , Ratas Sprague-Dawley , Factores de Tiempo , Familia-src Quinasas/metabolismo
12.
Hippocampus ; 20(1): 65-77, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19330848

RESUMEN

alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) are responsible for excitotoxicity induced by ischemic injury in hippocampal CA1 neurons, whereas the molecular mechanisms responsible for their neurotrophic activities are much less studied. Here, we examined the neuroprotective effect of positive modeulation of AMPARs by coapplication of AMPA with PEPA, an allosteric potentiator of AMPARs. We showed that coapplication of AMPA with PEPA protected hippocampal CA1 neurons from brain ischemia-induced death. Coapplication of AMPA with PEPA could prevent downregulated expression of GluR2 subunit caused by ischemia and increase BDNF expression via Lyn-ERK1/2-CREB signaling. Furthermore, TrkB receptor-mediated PI3K/Akt signal pathway was activated after coapplication of AMPA with PEPA, which was related to MAPK pathway and protected CA1 neurons against ischemic insults through depression of JNK3 activity, release of cytochrome c to cytosol and depression of capase-3 activity. Our results revealed that positive modulation of AMPARs could exert neuroprotective effects and the possible signaling pathways underlied.


Asunto(s)
Isquemia Encefálica/metabolismo , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Receptores AMPA/metabolismo , Familia-src Quinasas/metabolismo , Animales , Región CA1 Hipocampal/metabolismo , Regulación de la Expresión Génica , Sistema de Señalización de MAP Quinasas , Masculino , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Neuronas/metabolismo , ARN Mensajero/metabolismo , Ratas , Ratas Endogámicas , Receptores AMPA/genética , Transducción de Señal
13.
Epilepsia ; 51(3): 391-403, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19694794

RESUMEN

PURPOSE: Past work has demonstrated that kainic acid (KA)-induced seizures could cause the enhancement of excitation and lead to neuronal death in rat hippocampus. To counteract such an imbalance between excitation and inhibition, we designed experiments by activating the inhibitory gamma-aminobutyric acid (GABA) receptor to investigate whether such activation suppresses the excitatory glutamate signaling induced by KA and to elucidate the underlying molecular mechanisms. METHODS: Muscimol coapplied with baclofen was intraperitoneally administrated to the rats 40 min before KA injection by intracerebroventricular infusion. Subsequently we used a series of methods including immunoprecipitation, immunoblotting, histologic analysis, and immunohistochemistry to analyze the interaction, expression, and phosphorylation of relevant proteins as well as the survival of the CA1/CA3 pyramidal neurons. RESULTS: Coadministration of muscimol and baclofen exerted neuroprotection against neuron death induced by KA; inhibited the increased assembly of the GluR6-PSD-95-MLK3 module induced by KA; and suppressed the activation of MLK3, MKK7, and JNK3. DISCUSSION: Taken together, we demonstrate that coactivation of the inhibitory GABA receptors can attenuate the excitatory JNK3 apoptotic signaling pathway via inhibiting the increased assembly of the GluR6-PSD-95-MLK3 signaling module induced by KA. This provides a new insight into the therapeutic approach to epileptic seizure.


Asunto(s)
Apoptosis/efectos de los fármacos , Baclofeno/farmacología , Agonistas del GABA/farmacología , Proteína Quinasa 10 Activada por Mitógenos/efectos de los fármacos , Muscimol/farmacología , Receptores de GABA/efectos de los fármacos , Convulsiones/metabolismo , Animales , Apoptosis/fisiología , Modelos Animales de Enfermedad , Homólogo 4 de la Proteína Discs Large , Humanos , Inmunohistoquímica , Péptidos y Proteínas de Señalización Intracelular/efectos de los fármacos , Ácido Kaínico/farmacología , Quinasas Quinasa Quinasa PAM/metabolismo , Masculino , Proteínas de la Membrana/metabolismo , Proteína Quinasa 10 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 10 Activada por Mitógenos/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores de GABA/metabolismo , Receptores de GABA-A/efectos de los fármacos , Receptores de Ácido Kaínico/efectos de los fármacos , Convulsiones/inducido químicamente , Receptor de Ácido Kaínico GluK2
14.
Neuron ; 48(4): 635-46, 2005 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-16301179

RESUMEN

Acid-sensing ion channels (ASICs) composed of ASIC1a subunit exhibit a high Ca(2+) permeability and play important roles in synaptic plasticity and acid-induced cell death. Here, we show that ischemia enhances ASIC currents through the phosphorylation at Ser478 and Ser479 of ASIC1a, leading to exacerbated ischemic cell death. The phosphorylation is catalyzed by Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) activity, as a result of activation of NR2B-containing N-methyl-D-aspartate subtype of glutamate receptors (NMDARs) during ischemia. Furthermore, NR2B-specific antagonist, CaMKII inhibitor, or overexpression of mutated form of ASIC1a with Ser478 or Ser479 replaced by alanine (ASIC1a-S478A, ASIC1a-S479A) in cultured hippocampal neurons prevented ischemia-induced enhancement of ASIC currents, cytoplasmic Ca(2+) elevation, as well as neuronal death. Thus, NMDAR-CaMKII cascade is functionally coupled to ASICs and contributes to acidotoxicity during ischemia. Specific blockade of NMDAR/CaMKII-ASIC coupling may reduce neuronal death after ischemia and other pathological conditions involving excessive glutamate release and acidosis.


Asunto(s)
Encéfalo/fisiopatología , Ataque Isquémico Transitorio/fisiopatología , Proteínas de la Membrana/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Neuronas , Receptores de N-Metil-D-Aspartato/metabolismo , Canales de Sodio/metabolismo , Canales Iónicos Sensibles al Ácido , Acidosis/patología , Acidosis/fisiopatología , Animales , Encéfalo/patología , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Muerte Celular , Células Cultivadas , Electrofisiología , Glucosa/deficiencia , Hipocampo/metabolismo , Hipocampo/patología , Humanos , Hipoxia/fisiopatología , Ataque Isquémico Transitorio/patología , Masculino , Proteínas de la Membrana/genética , Mutación , Proteínas del Tejido Nervioso/genética , Fosforilación , Ratas , Ratas Sprague-Dawley , Canales de Sodio/genética
15.
Hippocampus ; 19(1): 79-89, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18680160

RESUMEN

Our previous study showed that kainate (KA) receptor subunit GluR6 played an important role in ischemia-induced MLK3 and JNK activation and neuronal degeneration through the GluR6-PSD95-MLK3 signaling module. However, whether the KA receptors subunit GluR6 is involved in the activation of p38 MAP kinase during the transient brain ischemia/reperfusion (I/R) in the rat hippocampal CA1 subfield is still unknown. In this present study, we first evaluated the time-course of phospho-p38 MAP kinase at various time-points after 15 min of ischemia and then observed the effects of antagonist of KA receptor subunit GluR6, GluR6 antisence oligodeoxynucleotides on the phosphorylation of p38 MAP kinase induced by I/R. Results showed that inhibiting KA receptor GluR6 or suppressing the expression of KA receptor GluR6 could down-regulate the elevation of phospho-p38 MAP kinase induced by I/R. These drugs also reduced the phosphorylation of MLK3, MKK3/MKK6, MKK4, and MAPKAPK2. Additionally, our results indicated administration of three drugs, including p38 MAP kinase inhibitor before brain ischemia significantly decreased the number of TUNEL-positive cells detected at 3 days of reperfusion and increased the number of the surviving CA1 pyramidal cells at 5 days of reperfusion after 15 min of ischemia. Taken together, we suggest that GluR6-contained KA receptors can mediate p38 MAP kinase activation through a kinase cascade, including MLK3, MKK3/MKK6, and MKK4 and then induce increased phosphorylation of MAPKAPK-2 during ischemia injury and ultimately result in neuronal cell death in the rat hippocampal CA1 region.


Asunto(s)
Hipocampo/metabolismo , Hipoxia-Isquemia Encefálica/metabolismo , Receptores de Ácido Kaínico/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Animales , Infarto Encefálico/metabolismo , Infarto Encefálico/patología , Infarto Encefálico/fisiopatología , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Modelos Animales de Enfermedad , Regulación hacia Abajo/efectos de los fármacos , Regulación hacia Abajo/fisiología , Activación Enzimática/fisiología , Inhibidores Enzimáticos/farmacología , Ácido Glutámico/metabolismo , Hipocampo/patología , Hipocampo/fisiopatología , Hipoxia-Isquemia Encefálica/patología , Hipoxia-Isquemia Encefálica/fisiopatología , Péptidos y Proteínas de Señalización Intracelular/metabolismo , MAP Quinasa Quinasa 3/metabolismo , Quinasas Quinasa Quinasa PAM/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Sistema de Señalización de MAP Quinasas/fisiología , Masculino , Oligodesoxirribonucleótidos Antisentido/farmacología , Fosforilación/efectos de los fármacos , Proteínas Serina-Treonina Quinasas/metabolismo , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/metabolismo , Daño por Reperfusión/patología , Daño por Reperfusión/fisiopatología , Transmisión Sináptica/fisiología , Proteina Quinasa Quinasa Quinasa 11 Activada por Mitógeno , Receptor de Ácido Kaínico GluK2
16.
J Neurosci Res ; 87(16): 3626-38, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19610093

RESUMEN

Recent studies have shown that kainate (KA) receptors are involved in neuronal cell death induced by seizure, which is mediated by the GluR6.PSD-95.MLK3 signaling module and subsequent JNK activation. In our previous studies, we demonstrated the neuroprotective role of a GluR6 c-terminus containing peptide against KA or cerebral ischemia-induced excitotoxicity in vitro and in vivo. Here, we first report that overexpression of the PDZ1 domain of PSD-95 protein exerts a protective role against neuronal death induced by cerebral ischemia-reperfusion in vivo and can prevent neuronal cell death induced by oxygen-glucose deprivation. Further studies show that overexpression of PDZ1 can perturb the interaction of GluR6 with PSD-95 and suppress the assembly of the GluR6.PSD-95.MLK3 signaling module and therefore inhibit JNK activation. Thus, it not only inhibits phosphorylation of c-Jun and down-regulates Fas ligand expression but also inhibits phosphorylation of 14-3-3 and decreases Bax translocation to mitochondria, decreases the release of cytochrome c, and decreases caspase-3 activation. Overall, the essential role of the PDZ1 domain of PSD-95 in apoptotic cell death in neurons provides an experimental foundation for gene therapy of neurodegenerative diseases with overexpression of the PDZ1 domain.


Asunto(s)
Hipocampo/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genética , Proteínas de la Membrana/genética , Neuronas/metabolismo , Daño por Reperfusión/metabolismo , Análisis de Varianza , Animales , Western Blotting , Muerte Celular/genética , Fraccionamiento Celular , Línea Celular , Células Cultivadas , Citocromos c/metabolismo , Homólogo 4 de la Proteína Discs Large , Glucosa/deficiencia , Hipocampo/patología , Humanos , Hipoxia/genética , Hipoxia/metabolismo , Inmunohistoquímica , Etiquetado Corte-Fin in Situ , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Masculino , Proteínas de la Membrana/metabolismo , Mitocondrias/genética , Mitocondrias/metabolismo , Neuronas/patología , Fosforilación/genética , Transporte de Proteínas/genética , Ratas , Ratas Sprague-Dawley , Receptores de Ácido Kaínico/metabolismo , Daño por Reperfusión/genética , Daño por Reperfusión/patología , Transducción de Señal/fisiología , Fracciones Subcelulares/metabolismo , Fracciones Subcelulares/patología , Proteína X Asociada a bcl-2/genética , Proteína X Asociada a bcl-2/metabolismo , Receptor de Ácido Kaínico GluK2
17.
J Recept Signal Transduct Res ; 29(1): 38-43, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19519168

RESUMEN

Here we examined the effects of ischemia preconditioning and ketamine, an NMDA receptor antagonist, on the activation and its nucleus translocation of ERK5 in hippocampal CA1 region. Our results showed ERK5 was not activated in rat hippocampus CA1 region. But in cytosol extracts preconditioned with 3 min of sublethal ischaemia, ERK5 activation was enhanced significantly, with two peaks occurring at 3 hr and 3 days, respectively. This activation returned to base level 3 days later. The results lead us to conclude that preconditioning increased the activations of ERK5 during reperfusion after lethal ischemia through NMDA receptor. Preconditioning increased the activation and nucleus translocation of ERK5 during reperfusion after lethal ischemia through the NMDA receptor. These findings might provide some clues to understanding the mechanism underlying ischemia tolerance and to finding clinical therapies for stroke using the endogenous neuroprotection.


Asunto(s)
Antagonistas de Aminoácidos Excitadores/metabolismo , Isquemia/metabolismo , Precondicionamiento Isquémico , Ketamina/metabolismo , Proteína Quinasa 7 Activada por Mitógenos/metabolismo , Transducción de Señal/fisiología , Transporte Activo de Núcleo Celular/fisiología , Animales , Activación Enzimática , Hipocampo/citología , Hipocampo/metabolismo , Masculino , Proteína Quinasa 7 Activada por Mitógenos/genética , Ratas , Ratas Sprague-Dawley
18.
Neurochem Res ; 34(11): 2008-21, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19449206

RESUMEN

Previous studies have shown that KA receptor subunit GluR6 mediated c-Jun N-terminal protein kinase (JNK) signaling is involved in global ischemia injury. Our present study indicates that focal ischemic brain insult on rat middle cerebral artery occlusion (MACo) model enhances the assembly of the GluR6-PSD95-MLK3 module and facilitates the phosphorylation of JNK. Most importantly, a peptide containing the TAT protein transduction sequence, Tat-GluR6-9c, can perturb the assembly of the GluR6-PSD95-MLK3 signaling module and suppress the activation of MLK3, MKK7/4 and JNK. As result, the inhibition of JNK activation caused by Tat-GluR6-9c diminishes the phosphorylation of the transcription factor c-Jun, down-regulates FasL expression and attenuates bax translocation, release of cytochrome c and the activation of caspase-3. Furthermore, MCAo induced infract volume is reduced by intracerebroventricular injection of Tat-Glur6-9c. Oxygen-glucose-deprivation (OGD) cultured cortical neuronal cell also shows an improved cell viability by application of Tat-GluR6-9c. Taken together, our findings strongly suggest that GluR6-PSD95-MLK3 signaling module mediated activation of nuclear and non-nuclear pathways of JNK activation are involved in focal ischemia injury and OGD. Tat-GluR6-9c, the peptide we constructed, gives a new insight into the therapy for ischemic stroke.


Asunto(s)
Glucosa/deficiencia , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Ataque Isquémico Transitorio/prevención & control , Proteínas de la Membrana/metabolismo , Fármacos Neuroprotectores/farmacología , Oxígeno/farmacología , Receptores de Ácido Kaínico/metabolismo , Proteínas Recombinantes de Fusión/farmacología , Productos del Gen tat del Virus de la Inmunodeficiencia Humana/genética , Animales , Corteza Cerebral/citología , Corteza Cerebral/metabolismo , Homólogo 4 de la Proteína Discs Large , Técnicas In Vitro , Ataque Isquémico Transitorio/metabolismo , Masculino , Mutación , Neuronas/citología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Fármacos Neuroprotectores/uso terapéutico , Ratas , Ratas Sprague-Dawley , Receptores de Ácido Kaínico/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/uso terapéutico , Receptor de Ácido Kaínico GluK2
19.
Environ Sci Pollut Res Int ; 26(18): 18615-18623, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31055745

RESUMEN

In this study, a new ecological dam based on the microbial fuel cell principle (MFCED) was designed to remove pollutants from river sediments and water bodies. Sediment organics were better removed in the MFCED mode in comparison with the other two modes (ecological dam with open circuit (OCED) and ecological dam filled with gravel in cathode chamber (GMFCED)). The difference of nitrogen source in water had little effect on the removal of chemical oxygen demand (COD) (70-80%), while nitrate was more readily removed in the MFCED. The voltage curve and power curve were measured to understand the bioelectricity generation of MFCED. During the stable operation phase of MFCED, the voltage was stabilized between 0.09-0.15 V. The results of high-throughput sequencing indicated that the anode and cathode diversities of MFCED were more than the other systems, and the species diversity of the anode was more than that of the cathode in the MFCED. Graphical abstract.


Asunto(s)
Fuentes de Energía Bioeléctrica , Restauración y Remediación Ambiental/métodos , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodos , Fuentes de Energía Bioeléctrica/microbiología , Análisis de la Demanda Biológica de Oxígeno , Electricidad , Electrodos/microbiología , Microbiota , Nitrógeno/aislamiento & purificación , Contaminantes Químicos del Agua/aislamiento & purificación
20.
Org Lett ; 21(18): 7315-7319, 2019 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-31475534

RESUMEN

The first example of copper-catalyzed enantioselective dearomative azidation of ß-naphthols using a readily available N3-transfer reagent is reported. A series of 2-hydroxy-1-naphthamides bearing a complex N-substituent were converted to the corresponding products in high yields with up to 96% ee, and chiral 1-azido-2-hydroxy-1-naphthoates were obtained with up to 90% ee under mild reaction conditions. The azides could be further transformed into the corresponding 1,2,3-triazoles smoothly via "click" reaction.

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