RESUMO
Some symmetrical and unsymmetrical thiacarbocyanines bearing NO-donor nitrooxy and furoxan moieties were synthesized and studied as candidate anti-Alzheimer's drugs. All products activated soluble guanylate cyclase (sGC) in a dose-dependent manner, depending on the presence in their structures of NO-donor groups. None displayed toxicity when tested at concentrations below 10 µM on human brain microvascular endothelial cells (hCMEC/D3). Some products were capable of inhibiting amyloid ß-protein (Aß) aggregation, with a potency in the low µM concentration range, and of inhibiting aggregation of human recombinant tau protein in amyloid fibrils when incubated with the protein at 1 µM concentration. Nitrooxy derivative 21 and furoxan derivative 22 were selected to investigate synaptic plasticity. Both products, tested at 2 µM concentration, counteracted the inhibition of long-term potentiation (LTP) induced by Aß42 in hippocampal brain slices.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Carbocianinas/uso terapêutico , Doadores de Óxido Nítrico/uso terapêutico , HumanosRESUMO
A key element to delineate the biology of individual tumors is the regulation of apoptosis. In this work, we functionally characterize two breast cancer associated genes, the proteasome 26S subunit ATPase 3 interacting protein (PSMC3IP) and the epithelial-stromal interaction 1 (EPSTI1), to explore their potential apoptotic role in breast cancer. We first explore the existence of direct physical interactions with annotated BC-apoptotic genes. Based on the generated interaction network, we examine several apoptotic markers to determine the effect of PSMC3IP and EPSTI1 gene expression modulation in two different human breast cancer cell lines to suggest potential molecular mechanisms to unveil their role in the disease. Our results show that PSMC3IP and EPSTI1 are able to modulate the extrinsic apoptotic pathway in estrogen receptor positive and triple negative breast cancer cell lines, highlighting them as potential therapeutic targets.
Assuntos
Apoptose/genética , Neoplasias da Mama/genética , Regulação Neoplásica da Expressão Gênica , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Transativadores/genética , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Feminino , HumanosRESUMO
Autosomal-dominant Alzheimer's disease (ADAD) is a genetic disorder caused by mutations in Amyloid Precursor Protein (APP) or Presenilin (PSEN) genes. Studying the mechanisms underlying these mutations can provide insight into the pathways that lead to AD pathology. The majority of biochemical studies on APP mutations to-date have focused on comparing mechanisms between mutations at different codons. It has been assumed that amino acid position is a major determinant of protein dysfunction and clinical phenotype. However, the differential effect of mutations at the same codon has not been sufficiently addressed. In the present study we compared the effects of the aggressive ADAD-associated APP I716F mutation with I716V and I716T on APP processing in human neuroglioma and CHO-K1 cells. All APP I716 mutations increased the ratio of Aß42/40 and changed the product line preference of γ-secretase towards Aß38 production. In addition, the APP I716F mutation impaired the ε-cleavage and the fourth cleavage of γ-secretase and led to abnormal APP ß-CTF accumulation at the plasma membrane. Taken together, these data indicate that APP mutations at the same codon can induce diverse abnormalities in APP processing, some resembling PSEN1 mutations. These differential effects could explain the clinical differences observed among ADAD patients bearing different APP mutations at the same position. The amyloid precursor protein (APP) I716F mutation is associated with autosomal dominant Alzheimer's disease with the youngest age-at-onset for the APP locus. Here, we describe that this mutation, when compared to two other familial Alzheimer's disease mutations at the same codon (I716V and I716T), interfered distinctly with γ-secretase cleavage. While all three mutations direct γ-secretase cleavage towards the 48â38 production line, the APP I716F mutation also impaired the ε-cleavage and the fourth cleavage of γ-secretase, resembling a PSEN1 mutation. These features may contribute to the aggressiveness of this mutation.
Assuntos
Doença de Alzheimer/genética , Peptídeos beta-Amiloides/biossíntese , Precursor de Proteína beta-Amiloide/genética , Adulto , Doença de Alzheimer/metabolismo , Secretases da Proteína Precursora do Amiloide/metabolismo , Animais , Células CHO , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Códon , Cricetinae , Cricetulus , Humanos , MutaçãoRESUMO
A key event in the pathogenesis of Alzheimer's disease (AD) is the accumulation of amyloid-ß (Aß) species in the brain, derived from the sequential cleavage of the amyloid precursor protein (APP) by ß- and γ-secretases. Based on a systems biology study to repurpose drugs for AD, we explore the effect of lansoprazole, and other proton-pump inhibitors (PPIs), on Aß production in AD cellular and animal models. We found that lansoprazole enhances Aß37, Aß40 and Aß42 production and lowers Aß38 levels on amyloid cell models. Interestingly, acute lansoprazole treatment in wild type and AD transgenic mice promoted higher Aß40 levels in brain, indicating that lansoprazole may also exacerbate Aß production in vivo. Overall, our data presents for the first time that PPIs can affect amyloid metabolism, both in vitro and in vivo.
Assuntos
2-Piridinilmetilsulfinilbenzimidazóis/farmacologia , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/biossíntese , Inibidores Enzimáticos/farmacologia , Inibidores da Bomba de Prótons , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/genética , Animais , Células CHO , Cricetinae , Cricetulus , Modelos Animais de Doenças , Feminino , Humanos , Lansoprazol , Camundongos , Camundongos KnockoutRESUMO
Autosomal-dominant Alzheimer disease (ADAD) is a genetic disorder caused by mutations in Amyloid Precursor Protein (APP) or Presenilin (PSEN) genes. Studies from families with ADAD have been critical to support the amyloid cascade hypothesis of Alzheimer disease (AD), the basis for the current development of amyloid-based disease-modifying therapies in sporadic AD (SAD). However, whether the pathological changes in APP processing in the CNS in ADAD are similar to those observed in SAD remains unclear. In this study, we measured ß-site APP-cleaving enzyme (BACE) protein levels and activity, APP and APP C-terminal fragments in brain samples from subjects with ADAD carrying APP or PSEN1 mutations (n = 18), patients with SAD (n = 27) and age-matched controls (n = 22). We also measured sAPPß and BACE protein levels, as well as BACE activity, in CSF from individuals carrying PSEN1 mutations (10 mutation carriers and 7 non-carrier controls), patients with SAD (n = 32) and age-matched controls (n = 11). We found that in the brain, the pattern in ADAD was characterized by an increase in APP ß-C-terminal fragment (ß-CTF) levels despite no changes in BACE protein levels or activity. In contrast, the pattern in SAD in the brain was mainly characterized by an increase in BACE levels and activity, with less APP ß-CTF accumulation than ADAD. In the CSF, no differences were found between groups in BACE activity or expression or sAPPß levels. Taken together, these data suggest that the physiopathological events underlying the chronic Aß production/clearance imbalance in SAD and ADAD are different. These differences should be considered in the design of intervention trials in AD.
Assuntos
Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Sistema Nervoso Central/metabolismo , Adulto , Idoso , Doença de Alzheimer/líquido cefalorraquidiano , Secretases da Proteína Precursora do Amiloide/líquido cefalorraquidiano , Secretases da Proteína Precursora do Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/líquido cefalorraquidiano , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Ácido Aspártico Endopeptidases/líquido cefalorraquidiano , Ácido Aspártico Endopeptidases/metabolismo , Western Blotting , Feminino , Heterozigoto , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Mutação/genética , Neuritos/patologia , Presenilina-1/líquido cefalorraquidiano , Presenilina-1/genéticaRESUMO
Here we postulate that the adapter protein evolutionarily conserved signalling intermediate in Toll pathway (ECSIT) might act as a molecular sensor in the pathogenesis of Alzheimer's disease (AD). Based on the analysis of our AD-associated protein interaction network, ECSIT emerges as an integrating signalling hub that ascertains cell homeostasis by the specific activation of protective molecular mechanisms in response to signals of amyloid-beta or oxidative damage. This converges into a complex cascade of patho-physiological processes. A failure to repair would generate severe mitochondrial damage and ultimately activate pro-apoptotic mechanisms, promoting synaptic dysfunction and neuronal death. Further support for our hypothesis is provided by increasing evidence of mitochondrial dysfunction in the disease etiology. Our model integrates seemingly controversial hypotheses for familial and sporadic forms of AD and envisions ECSIT as a biomarker to guide future therapies to halt or prevent AD.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Doença de Alzheimer/patologia , Mitocôndrias/patologia , Estresse Oxidativo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Idade de Início , Doença de Alzheimer/genética , Doença de Alzheimer/imunologia , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/genética , Peptídeos beta-Amiloides/metabolismo , Apoptose , Cromossomos Humanos/genética , Cromossomos Humanos/metabolismo , Predisposição Genética para Doença , Homeostase , Humanos , Imunidade Inata , Inflamação/imunologia , Inflamação/patologia , Mitocôndrias/imunologia , Mitocôndrias/metabolismo , Presenilina-1/genética , Presenilina-1/metabolismo , Presenilina-2/genética , Presenilina-2/metabolismo , Mapeamento de Interação de Proteínas , Mapas de Interação de Proteínas , Transdução de SinaisRESUMO
NMDA receptor (NMDAR) stimulation promotes neuronal survival during brain development. Cerebellar granule cells (CGCs) need NMDAR stimulation to survive and develop. These neurons differentiate and mature during its migration from the external granular layer to the internal granular layer, and lack of excitatory inputs triggers their apoptotic death. It is possible to mimic this process in vitro by culturing CGCs in low KCl concentrations (5 mm) in the presence or absence of NMDA. Using this experimental approach, we have obtained whole genome expression profiles after 3 and 8 h of NMDA addition to identify genes involved in NMDA-mediated survival of CGCs. One of the identified genes was Nurr1, a member of the orphan nuclear receptor subfamily Nr4a. Our results report a direct regulation of Nurr1 by CREB after NMDAR stimulation. ChIP assay confirmed CREB binding to Nurr1 promoter, whereas CREB shRNA blocked NMDA-mediated increase in Nurr1 expression. Moreover, we show that Nurr1 is important for NMDAR survival effect. We show that Nurr1 binds to Bdnf promoter IV and that silencing Nurr1 by shRNA leads to a decrease in brain-derived neurotrophic factor (BDNF) protein levels and a reduction of NMDA neuroprotective effect. Also, we report that Nurr1 and BDNF show a similar expression pattern during postnatal cerebellar development. Thus, we conclude that Nurr1 is a downstream target of CREB and that it is responsible for the NMDA-mediated increase in BDNF, which is necessary for the NMDA-mediated prosurvival effect on neurons.
Assuntos
Neurônios/citologia , Neurônios/metabolismo , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Inativação Gênica , N-Metilaspartato/farmacologia , Neurônios/efeitos dos fármacos , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/deficiência , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Ratos , Ratos Wistar , Ativação Transcricional/efeitos dos fármacosRESUMO
BACKGROUND: The simultaneous accumulation of different misfolded proteins in the central nervous system is a common feature in many neurodegenerative diseases. In most cases, co-occurrence of abnormal deposited proteins is observed in different brain regions and cell populations, but, in some instances, the proteins can be found in the same cellular aggregates. Co-occurrence of tau and α-synuclein (α-syn) aggregates has been described in neurodegenerative disorders with primary deposition of α-syn, such as Parkinson's disease and dementia with Lewy bodies. Although it is known that tau and α-syn have pathological synergistic effects on their mutual fibrillization, the underlying biological effects remain unclear. METHODOLOGY/PRINCIPAL FINDINGS: We used different cell models of synucleinopathy to investigate the effects of tau on α-syn aggregation. Using confocal microscopy and FRET-based techniques we observed that tau colocalized and interacted with α-syn aggregates. We also found that tau overexpression changed the pattern of α-syn aggregation, reducing the size and increasing the number of aggregates. This shift was accompanied by an increase in the levels of insoluble α-syn. Furthermore, co-transfection of tau increased secreted α-syn and cytotoxicity. CONCLUSIONS/SIGNIFICANCE: Our data suggest that tau enhances α-syn aggregation and toxicity and disrupts α-syn inclusion formation. This pathological synergistic effect between tau and α-syn may amplify the deleterious process and spread the damage in neurodegenerative diseases that show co-occurrence of both pathologies.
Assuntos
Modelos Biológicos , alfa-Sinucleína/metabolismo , Proteínas tau/fisiologia , Western Blotting , Linhagem Celular , Ensaio de Imunoadsorção Enzimática , Transferência Ressonante de Energia de Fluorescência , Humanos , Microscopia Confocal , Peso Molecular , alfa-Sinucleína/biossíntese , alfa-Sinucleína/toxicidadeRESUMO
Tauopathies are neurodegenerative diseases characterized by insoluble hyperphosphorylated deposits of the microtubule-associated protein tau in the central nervous system. In these disorders, tau is believed to cause neurodegeneration and neuronal loss due to the loss of function of the normal protein, and/or the gain of toxic properties by generating multimeric species. The obstacles found in amyloid-based therapies in Alzheimer's disease, the most common tauopathy, have stimulated the search for alternative targets, including tau. In this article, we review the strategies aimed at reducing tau phosphorylation and aggregation as a target for drug intervention in tauopathies.
Assuntos
Sistemas de Liberação de Medicamentos/métodos , Drogas em Investigação/uso terapêutico , Tauopatias/tratamento farmacológico , Tauopatias/metabolismo , Proteínas tau/metabolismo , Animais , Humanos , Modelos Neurológicos , Degeneração Neural/metabolismo , Degeneração Neural/patologia , Emaranhados Neurofibrilares/patologia , Fosforilação , Tauopatias/genética , Tauopatias/patologia , Proteínas tau/genéticaRESUMO
Bone morphogenetic proteins (BMPs) have been implicated in the generation and postnatal differentiation of cerebellar granule cells (CGCs). Here, we examined the eventual role of BMPs on the survival of these neurons. Lack of depolarization causes CGC death by apoptosis in vivo, a phenomenon that is mimicked in vitro by deprivation of high potassium in cultured CGCs. We have found that BMP-6, but not BMP-7, is able to block low potassium-mediated apoptosis in CGCs. The neuroprotective effect of BMP-6 is not accompanied by an increase of Smad translocation to the nucleus, suggesting that the canonical pathway is not involved. By contrast, activation of the MEK/ERK/CREB pathway by BMP-6 is necessary for its neuroprotective effect, which involves inhibition of caspase activity and an increase in Bcl-2 protein levels. Other pathways involved in the regulation of CGC survival, such as the c-Jun terminal kinase and the phosphatidylinositol 3-kinase (PI3K)-Akt/PKB, were not affected by BMP-6. Moreover, failure of BMP-7 to activate the MEK/ERK/CREB pathway could explain its inability to protect CGCs from low potassium-mediated apoptosis. Thus, this study demonstrates that BMP-6 acting through the noncanonical MEK/ERK/CREB pathway plays a crucial role on CGC survival.
Assuntos
Proteína Morfogenética Óssea 6/farmacologia , Cerebelo/citologia , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Neurônios/citologia , Animais , Apoptose/efeitos dos fármacos , Inibidores de Caspase , Diferenciação Celular/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Citoproteção/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Modelos Biológicos , Neurônios/enzimologia , Potássio/farmacologia , Transporte Proteico/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ratos , Ratos Wistar , Proteínas Smad/metabolismoRESUMO
TNF-alpha has been reported to be relevant in stroke-induced neuronal death. However the precise function of TNF-alpha in brain ischemia remains controversial since there are data supporting either a detrimental or a protective effect. Here we show that TNF-alpha is released after oxygen-glucose deprivation (OGD) of cortical cultures and is a major contributor to the apoptotic death observed without affecting the OGD-mediated necrotic cell death. In this paradigm, apoptosis depends on TNF-alpha-induced activation of caspase-8 and -3 without affecting the activation of caspase-9. By using knock-out mice for TNF-alpha receptor 1, we show that the activation of both caspase-3 and -8 by TNF-alpha is mediated by TNF-alpha receptor 1. The pro-apoptotic role of TNF-alpha in OGD is restricted to neurons and microglia, since astrocytes do not express either TNF-alpha or TNF-alpha receptor 1. Altogether, these results show that apoptosis of cortical neurons after OGD is mediated by TNF-alpha/TNF-alpha receptor 1.
Assuntos
Apoptose/fisiologia , Caspase 3/metabolismo , Caspase 8/metabolismo , Córtex Cerebral/fisiologia , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Hipóxia Celular/fisiologia , Células Cultivadas , Córtex Cerebral/citologia , Glucose/deficiência , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia/fisiologia , Neurônios/fisiologia , Ratos , Ratos Sprague-Dawley , Receptores Tipo I de Fatores de Necrose Tumoral/genéticaRESUMO
Upon activation, tumor necrosis factor alpha (TNF-alpha) receptor can engage apoptotic or survival pathways. Inhibition of macromolecular synthesis is known to sensitize cells to TNF-alpha-induced cell death. It is believed that this sensitization is due to the transcriptional blockade of genes regulated by NF-kappaB. Nevertheless, such evidence has remained elusive in the nervous system. Here, we show that TNF-alpha cannot normally induce apoptosis in PC12 cells or cortical neurons. However, cells treated with Actinomycin D (ActD) become susceptible to TNF-alpha-induced cell death through the activation of caspase-8, generation of tBid and activation of caspase-9 and -3. Analysis of several proteins involved in TNF-alpha receptor signaling showed no significant downregulation of NF-kappaB target genes, such as IAPs or FLIP, under such conditions. However, Bcl-x(L) protein levels, but not those of Bcl-2, Bax and Bak, are reduced by ActD or TNF-alpha/ActD treatments. Moreover, Bcl-x(L) overexpression fully protects cells against TNF-alpha/ActD-induced cell death. When endogenous levels of Bcl-x(L) are specifically downregulated by lentiviral-based RNAi, cells no longer require ActD to be sensitive to TNF-alpha-triggered apoptosis. Furthermore, Bcl-x(L) downregulation does not affect TNF-alpha-mediated NF-kappaB activation. Altogether, our results demonstrate that Bcl-x(L), and not Bcl-2, FLIP or IAPs, acts as the endogenous regulator of neuronal resistance/sensitivity to TNF-alpha-induced apoptosis in an NF-kappaB-independent manner.
Assuntos
Apoptose , NF-kappa B/metabolismo , Fator de Necrose Tumoral alfa/toxicidade , Proteína bcl-X/metabolismo , Animais , Antibacterianos/farmacologia , Apoptose/genética , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD/metabolismo , Caspase 3/metabolismo , Caspase 8/metabolismo , Caspase 9/metabolismo , Células Cultivadas , Dactinomicina/farmacologia , Proteínas Inibidoras de Apoptose/metabolismo , NF-kappa B/antagonistas & inibidores , Células PC12 , Inibidores da Síntese de Proteínas/farmacologia , Ratos , Transdução de Sinais , Fator de Necrose Tumoral alfa/genética , Proteína bcl-X/genéticaRESUMO
Death receptors (DRs) and their ligands are expressed in developing nervous system. However, neurons are generally resistant to death induction through DRs and rather their activation promotes neuronal outgrowth and branching. These results suppose the existence of DRs antagonists expressed in the nervous system. Fas apoptosis inhibitory molecule (FAIM(S)) was first identified as a Fas antagonist in B-cells. Soon after, a longer alternative spliced isoform with unknown function was identified and named FAIM(L). FAIM(S) is widely expressed, including the nervous system, and we have shown previously that it promotes neuronal differentiation but it is not an anti-apoptotic molecule in this system. Here, we demonstrate that FAIM(L) is expressed specifically in neurons, and its expression is regulated during the development. Expression could be induced by NGF through the extracellular regulated kinase pathway in PC12 (pheochromocytoma cell line) cells. Contrary to FAIM(S), FAIM(L) does not increase the neurite outgrowth induced by neurotrophins and does not interfere with nuclear factor kappaB pathway activation as FAIM(S) does. Cells overexpressing FAIM(L) are resistant to apoptotic cell death induced by DRs such as Fas or tumor necrosis factor R1. Reduction of endogenous expression by small interfering RNA shows that endogenous FAIM(L) protects primary neurons from DR-induced cell death. The detailed analysis of this antagonism shows that FAIM(L) can bind to Fas receptor and prevent the activation of the initiator caspase-8 induced by Fas. In conclusion, our results indicate that FAIM(L) could be responsible for maintaining initiator caspases inactive after receptor engagement protecting neurons from the cytotoxic action of death ligands.
Assuntos
Proteínas Reguladoras de Apoptose/biossíntese , Proteínas Reguladoras de Apoptose/genética , Apoptose/fisiologia , Proteínas Inibidoras de Apoptose/fisiologia , Neurônios/metabolismo , Receptores de Morte Celular/antagonistas & inibidores , Receptores de Morte Celular/fisiologia , Animais , Apoptose/genética , Proteínas Reguladoras de Apoptose/fisiologia , Células Cultivadas , Regulação da Expressão Gênica/fisiologia , Variação Genética/fisiologia , Humanos , Camundongos , Neurônios/patologia , Células PC12 , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , Isoformas de Proteínas/fisiologia , Ratos , Receptores de Morte Celular/genéticaRESUMO
BACKGROUND AND PURPOSE: Administration of histamine receptor antagonists has been reported to produce contradictory results, either reducing or increasing neural damage induced by ischemia. In this study, we investigated the neuroprotective effects of histamine H2-receptor antagonists in an "in vitro" model of ischemia. METHODS: Cultured rat brain cortical neurons were exposed to oxygen-glucose deprivation (OGD) in the presence or absence of different histaminergic drugs. Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide reduction assay. Necrosis and apoptosis were quantified by staining cells with propidium iodide and Hoechst 33258. Caspase 3 activation was determined by immunocytochemistry and Western blot. RESULTS: Pretreatment with H2 antagonists effectively reduced neuronal cell death induced by OGD. Ranitidine decreased the number of necrotic and apoptotic cells. Caspase 3 activation and alteration of the neuronal cytoskeleton were also prevented by ranitidine pretreatment. The neuroprotective effect of ranitidine was still evident when added 6 hours after OGD. CONCLUSIONS: H2-receptor antagonists protected against OGD-induced neuronal death. Ranitidine attenuated cell death even when administered after OGD. These data suggest that this drug, which is currently used for the treatment of gastric ulcers, may be useful in promoting recovery after ischemia.