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C-Jun-N-terminal-kinases (JNKs), members of the mitogen-activated-protein-kinase family, are significantly linked with neurological and neurodegenerative pathologies and cancer progression. However, JNKs serve key roles under physiological conditions, particularly within the central-nervous-system (CNS), where they are critical in governing neural proliferation and differentiation during both embryogenesis and adult stages. These processes control the development of CNS, avoiding neurodevelopment disorders. JNK are key to maintain the proper activity of neural-stem-cells (NSC) and neural-progenitors (NPC) that exist in adults, which keep the convenient brain plasticity and homeostasis. This review underscores how the interaction of JNK with upstream and downstream molecules acts as a regulatory mechanism to manage the self-renewal capacity and differentiation of NSC/NPC during CNS development and in adult neurogenic niches. Evidence suggests that JNK is reliant on non-canonical Wnt components, Fbw7-ubiquitin-ligase, and WDR62-scaffold-protein, regulating substrates such as transcription factors and cytoskeletal proteins. Therefore, understanding which pathways and molecules interact with JNK will bring knowledge on how JNK activation orchestrates neuronal processes that occur in CNS development and brain disorders.
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Diferenciación Celular , Células-Madre Neurales , Neurogénesis , Humanos , Animales , Diferenciación Celular/fisiología , Células-Madre Neurales/metabolismo , Células-Madre Neurales/citología , Neurogénesis/fisiología , Sistema de Señalización de MAP Quinasas/fisiología , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Neuronas/metabolismo , Neuronas/citologíaRESUMEN
Background: Mesenchymal stem cells (MSCs) are multipotent precursor cells with the ability to self-renew and differentiate into multiple cell linage, including the Schwann-like fate that promotes regeneration after lesion. Raman spectroscopy provides a precise characterization of the osteogenic, adipogenic, hepatogenic and myogenic differentiation of MSCs. However, the differentiation of bone marrow mesenchymal stem cells (BMSCs) towards a glial phenotype (Schwann-like cells) has not been characterized before using Raman spectroscopy. Method: We evaluated three conditions: 1) cell culture from rat bone marrow undifferentiated (uBMSCs), and two conditions of differentiation; 2) cells exposed to olfactory ensheathing cells-conditioned medium (dBMSCs) and 3) cells obtained from olfactory bulb (OECs). uBMSCs phenotyping was confirmed by morphology, immunocytochemistry and flow cytometry using antibodies of cell surface: CD90 and CD73. Glial phenotype of dBMSCs and OECs were verified by morphology and immunocytochemistry using markers of Schwann-like cells and OECs such as GFAP, p75 NTR and O4. Then, the Principal Component Analysis (PCA) of Raman spectroscopy was performed to discriminate components from the high wavenumber region between undifferentiated and glial-differentiated cells. Raman bands at the fingerprint region also were used to analyze the differentiation between conditions. Results: Differences between Raman spectra from uBMSC and glial phenotype groups were noted at multiple Raman shift values. A significant decrease in the concentration of all major cellular components, including nucleic acids, proteins, and lipids were found in the glial phenotype groups. PCA analysis confirmed that the highest spectral variations between groups came from the high wavenumber region observed in undifferentiated cells and contributed with the discrimination between glial phenotype groups. Conclusion: These findings support the use of Raman spectroscopy for the characterization of uBMSCs and its differentiation in the glial phenotype.
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Vascular endothelial growth factor (VEGF) exerts neuroprotective or proinflammatory effects, depending on what VEGF forms (A-E), receptor types (VEGFR1-3), and intracellular signaling pathways are involved. Neonatal monosodium glutamate (MSG) treatment triggers neuronal death by excitotoxicity, which is commonly involved in different neurological disorders, including neurodegenerative diseases. This study was designed to evaluate the effects of VEGFR-2 inhibition on neuronal damage triggered by excitotoxicity in the cerebral motor cortex (CMC) and hippocampus (Hp) after neonatal MSG treatment. MSG was administered at a dose of 4 g/kg of body weight (b.w.) subcutaneously on postnatal days (PD) 1, 3, 5, and 7, whereas the VEGFR-2 inhibitor SU5416 was administered at a dose of 10 mg/kg b.w. subcutaneously on PD 5 and 7, 30 min before the MSG treatment. Neuronal damage was assessed using hematoxylin and eosin staining, fluoro-Jade staining, and TUNEL assay. Additionally, western blot assays for some proteins of the VEGF-A/VEGFR-2 signaling pathway (VEGF-A, VEGFR-2, PI3K, Akt, and iNOS) were carried out. All assays were performed on PD 6, 8, 10, and 14. Inhibition of VEGFR-2 signaling by SU5416 increases the neuronal damage induced by neonatal MSG treatment in both the CMC and Hp. Moreover, neonatal MSG treatment increased the expression levels of the studied VEGF-A/VEGFR-2 signaling pathway proteins, particularly in the CMC. We conclude that VEGF-A/VEGFR-2 signaling pathway activation could be part of the neuroprotective mechanisms that attempt to compensate for neuronal damage induced by neonatal MSG treatment and possibly also in other conditions involving excitotoxicity.
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Hipocampo , Corteza Motora , Receptor 2 de Factores de Crecimiento Endotelial Vascular , Hipocampo/efectos de los fármacos , Corteza Motora/efectos de los fármacos , Glutamato de Sodio/toxicidad , Factor A de Crecimiento Endotelial Vascular/metabolismo , Receptor 2 de Factores de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Receptor 2 de Factores de Crecimiento Endotelial Vascular/metabolismo , AnimalesRESUMEN
The increases in population ageing and growth are leading to a boosting in the number of people living with dementia, Alzheimer's disease (AD) being the most common cause. In spite of decades of intensive research, no cure for AD has been found yet. However, some treatments that may change disease progression and help control symptoms have been proposed. Beyond the classical hypotheses of AD etiopathogenesis, i.e., amyloid beta peptide (Aß) accumulation and tau hyperphosphorylation, a trend in attributing a key role to other molecular mechanisms is prompting the study of different therapeutic targets. Hence, drugs designed to modulate inflammation, insulin resistance, synapses, neurogenesis, cardiovascular factors and dysbiosis are shaping a new horizon in AD treatment. Within this frame, an increase in the number of candidate drugs for disease modification treatments is expected, as well as a focus on potential combinatory multidrug strategies.The present review summarizes the latest advances in drugs targeting Aß and tau as major contributors to AD pathophysiology. In addition, it introduces the most important drugs in clinical studies targeting alternative mechanisms thought to be involved in AD's neurodegenerative process.
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Enfermedad de Alzheimer , Enfermedad de Alzheimer/tratamiento farmacológico , Péptidos beta-Amiloides , Progresión de la Enfermedad , HumanosRESUMEN
(1) Background: The c-Jun-NH2-terminal protein kinase (JNK) is a mitogen-activated protein kinase involved in regulating physiological processes in the central nervous system. However, the dual genetic deletion of Mkk4 and Mkk7 (upstream activators of JNK) in adult mice is not reported. The aim of this study was to induce the genetic deletion of Mkk4/Mkk7 in adult mice and analyze their effect in hippocampal neurogenesis. (2) Methods: To achieve this goal, Actin-CreERT2 (Cre+/-), Mkk4flox/flox, Mkk7flox/flox mice were created. The administration of tamoxifen in these 2-month-old mice induced the gene deletion (Actin-CreERT2 (Cre+/-), Mkk4∆/∆, Mkk7∆/∆ genotype), which was verified by PCR, Western blot, and immunohistochemistry techniques. (3) Results: The levels of MKK4/MKK7 at 7 and 14 days after tamoxifen administration were not eliminated totally in CNS, unlike what happens in the liver and heart. These data could be correlated with the high levels of these proteins in CNS. In the hippocampus, the deletion of Mkk4/Mkk7 induced a misalignment position of immature hippocampal neurons together with alterations in their dendritic architecture pattern and maturation process jointly to the diminution of JNK phosphorylation. (4) Conclusion: All these data supported that the MKK4/MKK7-JNK pathway has a role in adult neurogenic activity.
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Hipocampo/fisiología , MAP Quinasa Quinasa 4/fisiología , MAP Quinasa Quinasa 7/fisiología , Sistema de Señalización de MAP Quinasas , Neurogénesis , Animales , Proteína Doblecortina , Eliminación de Gen , Ratones TransgénicosRESUMEN
Given the highly multifactorial origin of Alzheimer's disease (AD) neuropathology, disentangling and orderly knowing mechanisms involved in sporadic onset are arduous. Nevertheless, when the elements involved are dissected into smaller pieces, the task becomes more accessible. This review aimed to describe the link between c-Jun N-terminal Kinases (JNKs), master regulators of many cellular functions, and the early alterations of AD: synaptic loss and dysregulation of neuronal transport. Both processes have a role in the posterior cognitive decline observed in AD. The manuscript focuses on the molecular mechanisms of glutamatergic, GABA, and cholinergic synapses altered by the presence of amyloid-ß aggregates and hyperphosphorylated tau, as well as on several consequences of the disruption of cellular processes linked to neuronal transport that is controlled by the JNK-JIP (c-jun NH2-terminal kinase (JNK)-interacting proteins (JIPs) complex, including the transport of AßPP or autophagosomes.
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Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Neuronas/metabolismo , Sinapsis/metabolismo , Enfermedad de Alzheimer/patología , Animales , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Sistemas de Liberación de Medicamentos/métodos , Ácido Glutámico/metabolismo , Humanos , Proteínas Quinasas JNK Activadas por Mitógenos/antagonistas & inhibidores , Factor de Crecimiento Nervioso/metabolismo , Neuronas/efectos de los fármacos , Neuronas/patología , Inhibidores de Proteínas Quinasas/administración & dosificación , Sinapsis/efectos de los fármacos , Sinapsis/patología , Ácido gamma-Aminobutírico/metabolismoRESUMEN
Substantial evidence in the literature demonstrates the pleiotropic effects of the administration of recombinant human erythropoietin (rhEPO) and its molecular variants in different tissues and organs, including the brain. Some of these reports suggest that the chemical properties of this molecule by itself or in combination with other agents (e.g., growth factors) could provide the necessary pharmacological characteristics to be considered a potential protective agent in neurological disorders such as Alzheimer's disease (AD). AD is a degenerative disorder of the brain, characterized by an aberrant accumulation of amyloid ß (Aß) and hyperphosphorylated tau (tau-p) proteins in the extracellular and intracellular space, respectively, leading to inflammation, oxidative stress, excitotoxicity, and other neuronal alterations that compromise cell viability, causing neurodegeneration in the hippocampus and the cerebral cortex. Unfortunately, to date, it lacks an effective therapeutic strategy for its treatment. Therefore, in this review, we analyze the evidence regarding the effects of exogenous EPOs (rhEPO and its molecular variants) in several in vivo and in vitro Aß and tau-p models of AD-type neurodegeneration, to be considered as an alternative protective treatment to this condition. Particularly, we focus on analyzing the differential effect of molecular variants of rhEPO when changes in doses, route of administration, duration of treatment or application times, are evaluated for the improved cellular alterations generated in this disease. This narrative review shows the evidence of the effectiveness of the exogenous EPOs as potential therapeutic molecules, focused on the mechanisms that establish cellular damage and clinical manifestation in the AD.
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The c-Jun N-terminal Kinases (JNKs) are a group of regulatory elements responsible for the control of a wide array of functions within the cell. In the central nervous system (CNS), JNKs are involved in neuronal polarization, starting from the cell division of neural stem cells and ending with their final positioning when migrating and maturing. This review will focus mostly on isoform JNK1, the foremost contributor of total JNK activity in the CNS. Throughout the text, research from multiple groups will be summarized and discussed in order to describe the involvement of the JNKs in the different steps of neuronal polarization. The data presented support the idea that isoform JNK1 is highly relevant to the regulation of many of the processes that occur in neuronal development in the CNS.
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Encéfalo/citología , Encéfalo/crecimiento & desarrollo , Polaridad Celular/fisiología , Proteína Quinasa 8 Activada por Mitógenos/metabolismo , Neuronas/metabolismo , Animales , Proteína Doblecortina , Humanos , Isoenzimas , Ratones , Fosforilación/fisiología , Transducción de Señal/fisiologíaRESUMEN
The blood-brain barrier (BBB) maintains the optimal microenvironment for brain function. Tight junctions (TJs) allow endothelial cells to adhere to each other, leading to the formation of a barrier that prevents the penetration of most molecules via transcellular routes. Evidence has indicated that seizure-induced vascular endothelial growth factor (VEGF) type 2 receptor (VEGFR-2) pathway activation weakens TJs, inducing vasodilatation and increasing vascular permeability and subsequent brain injury. The present study focused on investigating the expression levels of VEGF-related (VEGF-A and VEGFR-2) and TJ-related proteins (claudin-5, occludin and ZO-1) in the neocortical microvasculature of patients with drug-resistant temporal lobe epilepsy (TLE). The results obtained from hippocampal sclerosis TLE (HS-TLE) patients were compared with those obtained from patients with TLE secondary to lesions (lesion-TLE) and autopsy samples. The Western blotting and immunofluorescence results showed that VEGF-A and VEGFR-2 protein expression levels were increased in HS-TLE and lesion-TLE patients compared to autopsy group. On the other hand, claudin-5 expression was higher in HS-TLE patients and lesion-TLE patients than autopsies. The expression level of occludin and ZO-1 was decreased in HS-TLE patients. Our study described modifications to the integrity of the BBB that may contribute to the pathogenesis of TLE, in which the VEGF system may play an important role. We demonstrated that the same modifications were present in both HS-TLE and lesion-TLE patients, which suggests that seizures modify these systems and that they are not associated with the establishment of epilepsy.
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Barrera Hematoencefálica/metabolismo , Epilepsia Refractaria/metabolismo , Epilepsia del Lóbulo Temporal/metabolismo , Microvasos/metabolismo , Neocórtex/irrigación sanguínea , Proteínas de Uniones Estrechas/metabolismo , Uniones Estrechas/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Adolescente , Adulto , Barrera Hematoencefálica/patología , Claudina-5/metabolismo , Epilepsia Refractaria/tratamiento farmacológico , Epilepsia Refractaria/patología , Epilepsia del Lóbulo Temporal/tratamiento farmacológico , Epilepsia del Lóbulo Temporal/patología , Femenino , Humanos , Masculino , Microvasos/patología , Persona de Mediana Edad , Ocludina/metabolismo , Transducción de Señal , Uniones Estrechas/patología , Receptor 2 de Factores de Crecimiento Endotelial Vascular/metabolismo , Adulto Joven , Proteína de la Zonula Occludens-1/metabolismoRESUMEN
Glutamate-mediated excitatory synaptic signalling is primarily controlled by excitatory amino acid transporters (EAATs), such as EAAT1 and EAAT2, which are located mostly on astrocytes and, together, uptake more than 95 % of extracellular glutamate. Alterations in the functional expression levels of EAATs can lead to excessive extracellular glutamate accumulation, potentially triggering excitotoxicity and seizures, among other neurological disorders. Excitotoxicity induced in early developmental stages can lead to lasting changes in several neurotransmission systems, including the glutamatergic system, which could make the brain more susceptible to a second insult. In this study, the expression levels of EAAT1 (GLAST) and EAAT2 (GLT-1) proteins were assessed in the cerebral motor cortex (CMC), striatum, hippocampus and entorhinal cortex (EC) of male adult rats following the neonatal excitotoxic process triggered by monosodium glutamate (MSG)-treatment (4 g/kg of body weight at postnatal days 1,3,5 and 7, subcutaneously). Western blot analysis showed that neonatal MSG-treatment decreased EAAT1 expression levels in the CMC, striatum and hippocampus, while EAAT2 levels were increased in the striatum and EC and decreased in the CMC. Immunofluorescence staining confirmed the changes in EAAT1 and EAAT2 expression induced by neonatal MSG-treatment, which were accompanied by an increase in the glial fibrillary acidic protein (GFAP) immunofluorescence signalthat was particularly significant in the hippocampus. Our results show that a neonatal excitotoxic processes can induce lasting changes in the expression levels of EAAT1 and EAAT2 proteins and suggest that although astrogliosis occurs, glutamate uptake could be deficient, particularly in the CMC and hippocampus.
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Encéfalo/crecimiento & desarrollo , Encéfalo/metabolismo , Transportador 1 de Aminoácidos Excitadores/biosíntesis , Transportador 2 de Aminoácidos Excitadores/biosíntesis , Glutamato de Sodio/toxicidad , Factores de Edad , Animales , Animales Recién Nacidos , Encéfalo/efectos de los fármacos , Transportador 1 de Aminoácidos Excitadores/antagonistas & inhibidores , Transportador 1 de Aminoácidos Excitadores/genética , Transportador 2 de Aminoácidos Excitadores/antagonistas & inhibidores , Transportador 2 de Aminoácidos Excitadores/genética , Expresión Génica , Ácido Glutámico/toxicidad , Masculino , Ratas , Ratas WistarAsunto(s)
Citocinas/metabolismo , Epilepsia del Lóbulo Temporal/inmunología , Microvasos/patología , Neocórtex/irrigación sanguínea , Óxido Nítrico Sintasa de Tipo II/metabolismo , Adolescente , Adulto , Estudios de Casos y Controles , Niño , Citocinas/análisis , Epilepsia del Lóbulo Temporal/patología , Epilepsia del Lóbulo Temporal/cirugía , Femenino , Humanos , Masculino , Microvasos/inmunología , Persona de Mediana Edad , Neocórtex/inmunología , Neocórtex/patología , Neocórtex/cirugía , Óxido Nítrico Sintasa de Tipo II/análisis , Adulto JovenRESUMEN
The original version of this article unfortunately contained mistake. The authors found that Fig. 4.B mistakenly displays an incorrect GAPDH image. The authors are truly regretful and apologize for the mistake.
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Early responses to a neurological excitotoxic process include blood-brain barrier (BBB) impairment and overexpression of vascular endothelial growth factor (VEGF), but the long-term effects of excitotoxicity on the BBB properties remain unknown. To assess this, we induced an excitotoxic process on male rats by neonatal monosodium glutamate (MSG) treatment. At postnatal day (PD) 60, we measured the expression level of structural proteins of the BBB and the VEGF type-2 receptor (VEGFR-2) protein in the cerebral motor cortex (CMC), striatum (STR), hippocampus (Hp), entorhinal cortex (Ent), and hypothalamus (Hyp). We also measured BBB permeability in the same cerebral regions. Neonatal MSG treatment significantly reduced the protein expression level of claudin-5 in the CMC, and of ZO-1 in the CMC and Hp, and increased the expression level of plasmalemmal vesicle-associated protein in the CMC, and of VEGFR-2 in all regions except for the Hyp. BBB permeability was significantly higher in all studied regions of MSG-treated animals after hypertonic shock (HS). The increased BBB permeability observed in the MSG-treated animals after HS was reversed by VEGFR-2 inhibition with SU5416. We conclude that neonatal excitotoxicity leads to lasting impairment on BBB properties in adulthood, increasing its susceptibility to HS that could be regulated by VEGFR-2 activity inhibition.
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Barrera Hematoencefálica/efectos de los fármacos , Glutamato de Sodio/toxicidad , Animales , Animales Recién Nacidos , Encéfalo/efectos de los fármacos , Química Encefálica/efectos de los fármacos , Indoles/farmacología , Masculino , Presión Osmótica/efectos de los fármacos , Pirroles/farmacología , Ratas , Ratas Wistar , Receptor 2 de Factores de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Receptor 2 de Factores de Crecimiento Endotelial Vascular/biosíntesis , Receptor 2 de Factores de Crecimiento Endotelial Vascular/genéticaRESUMEN
In the epilepsy spectrum, temporal lobe epilepsy (TLE) is the most common and devastating focal and symptomatic epilepsy form in adults, where more than 30% of patients develop pharmacoresistance. It is not fully understood how the gene expression contributes to establishing an epileptic phenotype. Cerebrovascular remodeling directed by VEGF (vascular endothelial growth factor) signaling might modulate the synaptic neurotransmission in the epileptic brain. To address this question, the gene expression was profiled in biopsies of the temporal cortex from diagnosed patients with pharmacoresistant TLE that underwent surgical resection to seizure control. One hundred sixty-eight genes related to VEGF signaling and GABA and glutamate neurotransmissions were evaluated. Genes related to downstream signaling -phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinases (MAPK), and Janus-activated kinase/signal transducer and activator of transcription (JAK/STAT) pathways- and neurotransmitters metabolism were evaluated too. Thirty-nine genes were upregulated. The genes encoding for G protein q polypeptide, serine racemase, gephyrin, and glutamate/cystine antiporter system xCT appeared as novel upregulated genes in the pharmacoresistant TLE. ClueGO, a Cytoscape plugin, was used to build a gene network associated using Gene Ontology (GO) terminology. Enrichment analysis by ClueGO retrieves that positive regulation of endothelial cell proliferation, nerve development, and neuronal apoptosis were over-represented categories. In conclusion, VEGF signaling is confirmed as a relevant mediator in the pharmacoresistant TLE. In addition, the enrichment analysis applied to differentially expressed genes suggests new pharmacological targets to be assessed in the treatment of pharmacoresistant TLE. Results make up an approximation to better understand the epileptic brain and complement the available data.
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Epilepsia Refractaria/metabolismo , Epilepsia del Lóbulo Temporal/metabolismo , Ácido Glutámico/metabolismo , Neocórtex/metabolismo , Receptores de GABA/metabolismo , Transcriptoma , Factor A de Crecimiento Endotelial Vascular/metabolismo , Adolescente , Adulto , Epilepsia Refractaria/genética , Epilepsia del Lóbulo Temporal/genética , Femenino , Humanos , Sistema de Señalización de MAP Quinasas , Masculino , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Persona de Mediana Edad , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Racemasas y Epimerasas/genética , Racemasas y Epimerasas/metabolismo , Receptores de GABA/genética , Factor A de Crecimiento Endotelial Vascular/genéticaRESUMEN
BACKGROUND: Erythropoietin (Epo) and vascular endothelial growth factor (VEGF) are two vasoactive molecules with essential trophic effects for brain development. The expression and secretion of both molecules increase in response to neuronal damage and they exert protective and restorative effects, which may also be accompanied by adverse side effects. OBJECTIVE: We review the most relevant evidence on the neuroprotective and neurorestorative effects of Epo and VEGF in three of the most frequent neurological disorders, namely, stroke, epilepsy and Alzheimer's disease, to develop new therapeutic approaches. METHODS: Several original scientific manuscripts and reviews that have discussed the evidence in critical way, considering both the beneficial and adverse effects of Epo and VEGF in the selected neurological disorders, were analysed. In addition, throughout this review, we propose several considerations to take into account in the design of therapeutic approaches based on Epo and VEGF signalling. RESULTS: Although the three selected disorders are triggered by different mechanisms, they evolve through similar processes: excitotoxicity, oxidative stress, neuroinflammation, neuronal death, glial reactivity and vascular remodelling. Epo and VEGF exert neuroprotective and neurorestorative effects by acting on these processes due to their pleiotropism. In general, the evidence shows that both Epo and VEGF reduce neuronal death but that at the vascular level, their effects are contradictory. CONCLUSION: Because the Epo and VEGF signalling pathways are connected in several ways, we conclude that more experimental studies, primarily studies designed to thoroughly assess the functional interactions between Epo and VEGF in the brain under both physiological and pathophysiological conditions, are needed.
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Eritropoyetina , Fármacos Neuroprotectores , Neuronas/fisiología , Neuroprotección , Fármacos Neuroprotectores/farmacología , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Epigallocatechin-3-gallate (EGCG), a catechin found in green tea, has been previously investigated for its neuroprotective effects in vitro and in vivo. In the present study, we aimed to evaluate its possible beneficial effects in a well-established preclinical mixed model of familial Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM) based on the use of transgenic APPswe/PS1dE9 (APP/PS1) mice fed with a high fat diet (HFD). C57BL/6 wild-type (WT) and APP/PS1 mice were used in this study. APP/PS1 mice were fed with a palmitic acid-enriched HFD (APP/PS1 HFD) containing 45% of fat mainly from hydrogenated coconut oil. Intraperitoneal glucose tolerance tests (IP-GTT) and insulin tolerance tests (IP-ITT) were performed. Western blot analyses were performed to analyse protein expression, and water maze and novel object recognition test were done to evaluate the cognitive process. EGCG treatment improves peripheral parameters such as insulin sensitivity or liver insulin pathway signalling, as well as central memory deficits. It also markedly increased synaptic markers and cAMP response element binding (CREB) phosphorylation rates, as a consequence of a decrease in the unfolded protein response (UPR) activation through the reduction in the activation factor 4 (ATF4) levels and posterior downregulation of protein tyrosine phosphatase 1B (PTP1B). Moreover, EGCG significantly decreased brain amyloid ß (Aß) production and plaque burden by increasing the levels of α-secretase (ADAM10). Also, it led to a reduction in neuroinflammation, as suggested by the decrease in astrocyte reactivity and toll-like receptor 4 (TLR4) levels. Collectively, evidence suggests that chronic EGCG prevents distinct neuropathological AD-related hallmarks. This study also provides novel insights into the metabolic and neurobiological mechanisms of EGCG against cognitive loss through its effects on UPR function, suggesting that this compound may be a promising disease-modifying treatment for neurodegenerative diseases.
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Péptidos beta-Amiloides/metabolismo , Catequina/análogos & derivados , Disfunción Cognitiva/tratamiento farmacológico , Dieta Alta en Grasa , Presenilina-1/metabolismo , Respuesta de Proteína Desplegada , Animales , Glucemia/metabolismo , Catequina/química , Catequina/farmacocinética , Catequina/farmacología , Catequina/uso terapéutico , Disfunción Cognitiva/sangre , Disfunción Cognitiva/complicaciones , Disfunción Cognitiva/fisiopatología , Hipocampo/efectos de los fármacos , Hipocampo/patología , Hipocampo/fisiopatología , Insulina/metabolismo , Hígado/metabolismo , Masculino , Trastornos de la Memoria/sangre , Trastornos de la Memoria/complicaciones , Trastornos de la Memoria/tratamiento farmacológico , Trastornos de la Memoria/fisiopatología , Ratones Endogámicos C57BL , Ratones Obesos , Ratones Transgénicos , Modelos Biológicos , Transducción de Señal , Aprendizaje Espacial/efectos de los fármacos , Distribución Tisular/efectos de los fármacos , Respuesta de Proteína Desplegada/efectos de los fármacosRESUMEN
Aging is associated with detrimental cellular and cognitive changes, making it an important public health concern; yet, many of these changes may be influenced by nutritional interventions. The natural sesquiterpene ß-caryophyllene (BCP) has anti-inflammatory and antioxidant effects that are mediated by cannabinoid type-2 receptor activation, and these actions promote neuroprotection in different animal models that involve a cognitive damage. Consequently, whether chronic administration of BCP might prevent the age-related cellular and cognitive damage in a model of aging induced by chronic d-galactose (GAL) consumption was assessed here. Male BALB/c mice were administered BCP (10 mg/kg, oral), GAL (300 mg/kg, intraperitoneal), or GAL+BCP, and long-term memory and cognitive flexibility were evaluated in the normal and the reverse phases of Morris water maze test. In addition, immunohistochemistry was performed on prefrontal and hippocampal brain slices to detect glial acidic fibrillary protein and DNA oxidation. Although GAL administration reduced cognitive flexibility (P = .0308), this functional damage was not reversed by administering BCP. However, GAL administration also elevated the total number of astrocytes and their interactions in the hippocampus, and increasing DNA oxidation in the prefrontal cortex. BCP administration impeded the rise in the total number of astrocytes (P = .0286) and the DNA oxidation (P = .0286) in mice that received GAL. Hence, although BCP did not improve cognitive flexibility, it did produce a neuroprotective effect at the molecular and cellular level in the GAL model of aging.
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Envejecimiento , Antioxidantes/farmacología , Daño del ADN/efectos de los fármacos , Proteína Ácida Fibrilar de la Glía/metabolismo , Sesquiterpenos Policíclicos/farmacología , Animales , Modelos Animales de Enfermedad , Galactosa , Hipocampo/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos BALB C , Neuroprotección , Estrés Oxidativo , Corteza Prefrontal/efectos de los fármacosRESUMEN
The development of metabolic alterations like insulin resistance has been associated with dysfunctions in mitochondrial oxidative capacity, induction of neuroinflammatory responses, and the appearance of cognitive impairments in the brain. The c-Jun N-terminal Kinase 1 (JNK1) is a potential key modulator of these mechanisms. The current study identifies a protective effect of whole-body JNK1 knockout in the presence of a high-fat diet (HFD). Specifically, the data suggest that mice missing JNK1 show increased insulin sensitivity and mitochondrial activity, as well as reduced body weight, and astrocyte and microglial reactivity. Finally, these animals are also protected against HFD-induced cognitive impairments as assessed through novel object recognition test, the observation of dendritic spines, and the levels of BDNF or other proteins like spinophilin and ARC. Thus, modulation of JNK1 activity seems like a promising approach for the design of therapies aimed at treating metabolic-induced cognitive impairments. KEY MESSAGES: JNK1 is a link between obesity/type 2 diabetes and cognitive loss Inhibition of JNK1 is neuroprotective JNK1 constitutes a therapeutic strategy for cognitive loss.
Asunto(s)
Disfunción Cognitiva/etiología , Diabetes Mellitus Tipo 2/complicaciones , Hipocampo/metabolismo , Mitocondrias/metabolismo , Proteína Quinasa 8 Activada por Mitógenos/metabolismo , Animales , Astrocitos/metabolismo , Peso Corporal/genética , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Disfunción Cognitiva/genética , Disfunción Cognitiva/metabolismo , Espinas Dendríticas/genética , Espinas Dendríticas/fisiología , Diabetes Mellitus Tipo 2/metabolismo , Dieta Alta en Grasa/efectos adversos , Resistencia a la Insulina/genética , Masculino , Pruebas de Memoria y Aprendizaje , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Proteínas de Microfilamentos/metabolismo , Microglía/metabolismo , Mitocondrias/enzimología , Mitocondrias/genética , Proteína Quinasa 8 Activada por Mitógenos/genética , Proteínas del Tejido Nervioso/metabolismoRESUMEN
Nowadays, Alzheimer's disease (AD) is a severe sociological and clinical problem. Since it was first described, there has been a constant increase in its incidence and, for now, there are no effective treatments since current approved medications have only shown short-term symptomatic benefits. Therefore, it is imperative to increase efforts in the search for molecules and non-pharmacological strategies that are capable of slowing or stopping the progress of the disease and, ideally, to reverse it. The amyloid cascade hypothesis based on the fundamental role of amyloid has been the central hypothesis in the last 30 years. However, since amyloid-directed treatments have shown no relevant beneficial results other theories have been postulated to explain the origin of the pathology. The brain is a highly metabolically active energy-consuming tissue in the human body. It has an almost complete dependence on the metabolism of glucose and uses most of its energy for synaptic transmission. Thus, alterations on the utilization or availability of glucose may be cause for the appearance of neurodegenerative pathologies like AD. In this review article, the hypothesis known as Type 3 Diabetes (T3D) will be evaluated by summarizing some of the data that has been reported in recent years. According to published research, the adherence over time to low saturated fatty acids diets in the context of the Mediterranean diet would reduce the inflammatory levels in brain, with a decrease in the pro-inflammatory glial activation and mitochondrial oxidative stress. In this situation, the insulin receptor pathway would be able to fine tune the mitochondrial biogenesis in neuronal cells, regulation the adenosine triphosphate/adenosine diphosphate intracellular balance, and becoming a key factor involved in the preservation of the synaptic connexions and neuronal plasticity. In addition, new targets and strategies for the treatment of AD will be considered in this review for their potential as new pharmacological or non-pharmacological approaches.