RESUMEN

Methylmercury (MeHg) is a ubiquitous environmental neurotoxicant whose mechanisms of action involve oxidation of endogenous nucleophilic groups (mainly thiols and selenols), depletion of antioxidant defenses, and disruption of neurotransmitter homeostasis. Diphenyl diselenide-(PhSe)2-a model diaryl diselenide, has been reported to display significant protective effects against MeHg-induced neurotoxicity under both in vitro and in vivo experimental conditions. In this study, we compared the protective effects of (PhSe)2 with those of RC513 (4,4'-diselanediylbis(2,6-di-tert-butylphenol), a novel diselenide-probucol-analog) against MeHg-induced toxicity in the neuronal (hippocampal) cell line HT22. Although both (PhSe)2 and RC513 significantly mitigated MeHg- and tert-butylhydroperoxide (t-BuOOH)-cytotoxicity, the probucol analog exhibited superior protective effects, which were observed earlier and at lower concentrations compared to (PhSe)2. RC513 treatment (at either 0.5 µM or 2 µM) significantly increased glutathione peroxidase (GPx) activity, which has been reported to counteract MeHg-toxicity. (PhSe)2 was also able to increase GPx activity, but only at 2 µM. Although both compounds increased the Gpx1 transcripts at 6 h after treatments, only RC513 was able to increase mRNA levels of Prx2, Prx3, Prx5, and Txn2, which are also involved in peroxide detoxification. RC513 (at 2 µM) significantly increased GPx-1 protein expression in HT22 cells, although (PhSe)2 displayed a minor (nonsignificant) effect in this parameter. In agreement, RC513 induced a faster and superior capability to cope with exogenously-added peroxide (t-BuOOH). In summary, when compared to the prototypical organic diaryl diselenide [(PhSe)2], RC513 displayed superior protective properties against MeHg-toxicity in vitro; this was paralleled by a more pronounced upregulation of defenses related to detoxification of peroxides, which are well-known MeHg-derived intermediate oxidant species.

Asunto(s)

Compuestos de Metilmercurio , Compuestos de Organoselenio , Derivados del Benceno/farmacología , Compuestos de Metilmercurio/toxicidad , Compuestos de Organoselenio/farmacología , Peróxidos , Probucol/farmacología

RESUMEN

Folic acid has been reported to exert antidepressant effects, but its ability to abrogate the depressive-like behavior and signaling pathways alterations elicited by an inflammatory model of depression remains to be established. This study examined: a) the efficacy of folic acid in a mouse model of depression induced by tumor necrosis factor (TNF-α); b) whether the administration of subthreshold doses of folic acid and antidepressants (fluoxetine, imipramine, and bupropion), MK-801, or 7-nitroindazole cause antidepressant-like effects; c) the effects of TNF-α and/or folic acid on hippocampal p38MAPK, Akt, ERK, and JNK phosphorylation. Folic acid reduced the immobility time in the tail suspension test (TST) in control mice (10-50 mg/kg, p.o) and abolished the depressive-like behavior elicited by TNF-α (0.001 fg/site, i.c.v.) in this test (1-50 mg/kg, p.o). Coadministration of subthreshold doses of folic acid (1 mg/kg, p.o.) and fluoxetine, imipramine, bupropion, MK-801, or 7-nitroindazole produced an antidepressant-like effect in mice exposed or not to TNF-α. TNF-α-treated mice presented increased p38MAPK phosphorylation and decreased Akt phosphorylation, and the later effect was prevented by folic acid (10 mg/kg, p.o.). Additionally, ERK1 phosphorylation was increased in mice treated with TNF-α + folic acid (1 mg/kg), but no effects on ERK2 or JNK1/2/3 phosphorylation were found in any group. The results indicate the efficacy of folic acid to counteract the depressive-like behavior induced by a pro-inflammatory cytokine, an effect that might be associated with the activation of monoaminergic systems, inhibition of N-methyl-d-aspartate (NMDA) receptors and nitric oxide (NO) synthesis, as well as Akt modulation.

Asunto(s)

Antidepresivos/farmacología , Conducta Animal/efectos de los fármacos , Depresión/inducido químicamente , Depresión/tratamiento farmacológico , Depresión/metabolismo , Ácido Fólico/farmacología , Factor de Necrosis Tumoral alfa/farmacología , Complejo Vitamínico B/farmacología , Animales , Antidepresivos/administración & dosificación , Modelos Animales de Enfermedad , Femenino , Ácido Fólico/administración & dosificación , Ratones , Complejo Vitamínico B/administración & dosificación

RESUMEN

Guanosine is a purine nucleoside that has been shown to exhibit antidepressant effects, but the mechanisms underlying its effect are not well established. We investigated if the antidepressant-like effect induced by guanosine in the tail suspension test (TST) in mice involves the modulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor, voltage-dependent calcium channel (VDCC), and brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB) pathway. We also evaluated if the antidepressant-like effect of guanosine is accompanied by an acute increase in hippocampal and prefrontocortical BDNF levels. Additionally, we investigated if the ability of guanosine to elicit a fast behavioral response in the novelty suppressed feeding (NSF) test is associated with morphological changes related to hippocampal synaptogenesis. The antidepressant-like effect of guanosine (0.05 mg/kg, p.o.) in the TST was prevented by DNQX (AMPA receptor antagonist), verapamil (VDCC blocker), K-252a (TrkBantagonist), or BDNF antibody. Increased P70S6K phosphorylation and higher synapsin I immunocontent in the hippocampus, but not in the prefrontal cortex, were observed 1 h after guanosine administration. Guanosine exerted an antidepressant-like effect 1, 6, and 24 h after its administration, an effect accompanied by increased hippocampal BDNF level. In the prefrontal cortex, BDNF level was increased only 1 h after guanosine treatment. Finally, guanosine was effective in the NSF test (after 1 h) but caused no alterations in dendritic spine density and remodeling in the ventral dentate gyrus (DG). Altogether, the results indicate that guanosine modulates targets known to be implicated in fast antidepressant behavioral responses (AMPA receptor, VDCC, and TrkB/BDNF pathway).

Asunto(s)

Antidepresivos/farmacología , Factor Neurotrófico Derivado del Encéfalo/efectos de los fármacos , Guanosina/farmacología , Glicoproteínas de Membrana/efectos de los fármacos , Proteínas Tirosina Quinasas/efectos de los fármacos , Receptores AMPA/agonistas , Transducción de Señal/efectos de los fármacos , Animales , Factor Neurotrófico Derivado del Encéfalo/biosíntesis , Canales de Calcio/efectos de los fármacos , Espinas Dendríticas/efectos de los fármacos , Conducta Alimentaria/efectos de los fármacos , Femenino , Suspensión Trasera , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Glicoproteínas de Membrana/biosíntesis , Ratones , Neurogénesis/efectos de los fármacos , Corteza Prefrontal/efectos de los fármacos , Corteza Prefrontal/metabolismo , Proteínas Tirosina Quinasas/biosíntesis , Sinapsis/efectos de los fármacos

RESUMEN

Fluoxetine is the foremost prescribed antidepressant. Drugs acting on monoaminergic system may also regulate glutamatergic system. Indeed, the investigation of proteins associated with this system, such as Narp (neuronal activity-dependent pentraxin) and GluA4 subunit of AMPA receptor may reveal poorly explored modulations triggered by conventional antidepressants. This study aimed to uncover neurochemical mechanisms underlying the chronic fluoxetine treatment, mainly by evaluating these protein targets in the prefrontal cortex and in the hippocampus. Mice received a daily administration of fluoxetine (0.1, 1 or 10 mg/kg, p.o.) or potable water (vehicle group) for 21 days. These animals were submitted to the forced swim test (FST) to verify antidepressant-like responses and the open-field test (OFT) to assess locomotor activity. Modulation of signaling proteins was analyzed by western blot. Chronic treatment with fluoxetine (1 and 10 mg/kg) was effective, since it reduced the immobility time in the FST, without altering locomotor activity. Fluoxetine 10 mg/kg increased CREB phosphorylation and BDNF expression in the prefrontal cortex and hippocampus. Noteworthy, in the hippocampus fluoxetine also promoted Akt activation and augmented Narp expression. In the prefrontal cortex, a significant decrease in the expression of the GluA4 subunit and Narp were observed following fluoxetine administration (10 mg/kg). The results provide evidence of novel molecular targets potentially involved in the antidepressant effects of fluoxetine, since in mature rodents Narp and GluA4 are mainly expressed in the GABAergic parvalbumin-positive (PV+) interneurons. This may bring new insights into the molecular elements involved in the mechanisms underlying the antidepressant effects of fluoxetine.

Asunto(s)

Antidepresivos de Segunda Generación/administración & dosificación , Proteína C-Reactiva/antagonistas & inhibidores , Sistemas de Liberación de Medicamentos/métodos , Fluoxetina/administración & dosificación , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Receptores AMPA/antagonistas & inhibidores , Animales , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Proteína C-Reactiva/metabolismo , Relación Dosis-Respuesta a Droga , Masculino , Ratones , Proteínas del Tejido Nervioso/metabolismo , Receptores AMPA/metabolismo

RESUMEN

Glioblastoma multiforme is the most aggressive type of glioma, with limited treatment and poor prognosis. Despite some advances over the last decade, validation of novel and selective antiglioma agents remains a challenge in clinical pharmacology. Prior studies have shown that leguminous lectins may exert various biological effects, including antitumor properties. Accordingly, this study aimed to evaluate the mechanisms underlying the antiglioma activity of ConBr, a lectin extracted from the Canavalia brasiliensis seeds. ConBr at lower concentrations inhibited C6 glioma cell migration while higher levels promoted cell death dependent upon carbohydrate recognition domain (CRD) structure. ConBr increased p38MAPK and JNK and decreased ERK1/2 and Akt phosphorylation. Moreover, ConBr inhibited mTORC1 phosphorylation associated with accumulation of autophagic markers, such as acidic vacuoles and LC3 cleavage. Inhibition of early steps of autophagy with 3-methyl-adenine (3-MA) partially protected whereas the later autophagy inhibitor Chloroquine (CQ) had no protective effect upon ConBr cytotoxicity. ConBr also augmented caspase-3 activation without affecting mitochondrial function. Noteworthy, the caspase-8 inhibitor IETF-fmk attenuated ConBr induced autophagy and C6 glioma cell death. Finally, ConBr did not show cytotoxicity against primary astrocytes, suggesting a selective antiglioma activity. In summary, our results indicate that ConBr requires functional CRD lectin domain to exert antiglioma activity, and its cytotoxicity is associated with MAPKs and Akt pathways modulation and autophagy- and caspase-8- dependent cell death.

Asunto(s)

Antineoplásicos/farmacología , Caspasa 8/metabolismo , Activación Enzimática/efectos de los fármacos , Glioma/tratamiento farmacológico , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Lectinas de Plantas/farmacología , Animales , Apoptosis/efectos de los fármacos , Astrocitos/efectos de los fármacos , Autofagia/efectos de los fármacos , Caspasa 3/metabolismo , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Glioma/metabolismo , Glioma/patología , Humanos , Ratones , Mitocondrias/efectos de los fármacos , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Simulación del Acoplamiento Molecular , Polisacáridos/metabolismo , Dominios Proteicos/fisiología , Estructura Cuaternaria de Proteína/fisiología , Estructura Terciaria de Proteína/fisiología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas

RESUMEN

Lectins are a group of proteins of non-immune origin recognized for their ability to bind reversibly to carbohydrates. Researchers have been intrigued by oligosaccharides and glycoconjugates for their involvement as mediators of complex cellular events and then many biotechnological applications of lectins are based on glycocode decoding and their activities. Here, we report a structural and biological study of a ConA-like mannose/glucose-specific lectin from Canavalia bonariensis seeds, CaBo. More specifically, we evaluate the binding of CaBo with α-methyl-D-mannoside (MMA) and mannose-1,3-α-D-mannose (M13) and the resultant in vivo effects on a rat model of acute inflammation. A virtual screening was also carried out to cover a larger number of possible bindings of CaBo. In silico analysis demonstrated the stability of CaBo interaction with mannose-type ligands, and the lectin was able to induce acute inflammation in rats with the participation of the carbohydrate recognition domain (CRD) and histamine release. These results confirm the ability of CaBo to interact with hybrid and high-mannose N-glycans, supporting the hypothesis that CaBo's biological activity occurs primarily through its interaction with cell surface glycosylated receptors.

Asunto(s)

Carbohidratos/química , Inflamación/tratamiento farmacológico , Lectinas de Unión a Manosa/farmacología , Lectinas de Plantas/farmacocinética , Animales , Sitios de Unión , Histamina/farmacología , Humanos , Inflamación/inducido químicamente , Inflamación/patología , Manosa/química , Lectinas de Unión a Manosa/química , Manósidos/química , Lectinas de Plantas/química , Lectinas de Plantas/farmacología , Polisacáridos/química , Ratas

RESUMEN

We investigated the ability of agmatine to potentiate the antidepressant-like and synaptic effects of ketamine in mice. Agmatine (0.1 and 1 mg/kg, p.o.) and ketamine (1 and 10 mg/kg, i.p.) produced an antidepressant-like effect in the tail suspension test. The combination of agmatine (0.01 mg/kg, p.o.) and ketamine (0.1 mg/kg, i.p.), at subthreshold doses, produced an antidepressant-like effect 1 h, 24 h and 7d after treatment. Western blot analysis from prefrontal cortex tissue showed that the combined treatment, after 1 h, increased p70S6K and GluA1, and reduced synapsin 1 phosphorylation. Additionally, after 24 h, Akt, p70S6K, GluA1, and synapsin 1 phosphorylation; and PSD95 immunocontent increased (which persisted for up to 7d). Dendritic architecture analysis of the prefrontal cortex revealed that the combined treatment improved dendritic arbor complexity (after 24 h, up to 7d), and increased spine density (after 1 h, up to 24 h). Morphometric analysis revealed a filopodia-shaped dendrite spine upregulation after 1 h. A predominance of stubby, mushroom, branched and filopodia; and a reduction in thin protrusions were observed after 24 h. Finally, mushroom-shaped dendritic spines predominance increased after 7d. Agmatine potentiated ketamine's antidepressant, and dendritic arbors and spines remodeling effects in a time-dependent manner. Our data indicate Akt/p70S6K signaling as a likely target for these effects.

Asunto(s)

Agmatina/farmacología , Antidepresivos/farmacología , Dendritas/efectos de los fármacos , Espinas Dendríticas/efectos de los fármacos , Ketamina/farmacología , Proteína Oncogénica v-akt/efectos de los fármacos , Proteínas Quinasas S6 Ribosómicas/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Sinapsis/efectos de los fármacos , Animales , Dendritas/ultraestructura , Espinas Dendríticas/ultraestructura , Sinergismo Farmacológico , Suspensión Trasera , Masculino , Ratones , Actividad Motora/efectos de los fármacos , Corteza Prefrontal/efectos de los fármacos

RESUMEN

Lectins from Diocleinae subtribe species (family Leguminosae) are of special interest since they present a wide spectrum of biological activities, despite their high structural similarity. During their synthesis in plant cells, these proteins undergo post-translational processing resulting in the formation of three chains (α, ß, γ), which constitute the lectins' subunits. Furthermore, such wild-type proteins are presented as isolectins or with different combinations of these chains, which undermine their biotechnological potential. Thus, the present study aimed to produce a recombinant form of the lectin from Dioclea sclerocarpa seeds (DSL), exclusively constituted by α-chain. The recombinant DSL (rDSL) was successfully expressed in E. coli BL21 (DE3) and purified by affinity chromatography (Sephadex G-50), showing a final yield of 74 mg of protein per liter of culture medium and specificity for D-mannose, α-methyl-mannoside and melibiose, unlike the wild-type protein. rDSL presented an effective vasorelaxant effect in rat aortas up to 100% and also interacted with glioma cells C6 and U87. Our results demonstrated an efficient recombinant production of rDSL in a bacterial system that retained some biochemical properties of the wild-type protein, showing wider versatility in sugar specificities and better efficacy in its activity in the biological models evaluated in this work.

Asunto(s)

Dioclea/química , Lectinas de Plantas/química , Animales , Aorta/efectos de los fármacos , Línea Celular Tumoral , Cromatografía de Afinidad , Escherichia coli/genética , Escherichia coli/metabolismo , Glioma/metabolismo , Hemaglutinación , Manosa/química , Lectinas de Plantas/metabolismo , Estructura Secundaria de Proteína , Ratas , Proteínas Recombinantes/análisis , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/farmacología , Semillas/química , Vasodilatadores/química

RESUMEN

Neuronal hippocampal death can be induced by exacerbated levels of cortisol, a condition usually observed in patients with Major depressive disorder (MDD). Previous in vitro and in vivo studies showed that ursolic acid (UA) elicits antidepressant and neuroprotective properties. However, the protective effects of UA against glucocorticoid-induced cytotoxicity have never been addressed. Using an in vitro model of hippocampal cellular death induced by elevated levels of corticosterone, we investigated if UA prevents corticosterone-induced cytotoxicity in HT22 mouse hippocampal derived cells. Concentrations lower than 25 µM UA did not alter cell viability. Co-incubation with UA for 48 h was able to protect HT22 cells from the reduction on cell viability and from the increase in apoptotic cells induced by corticosterone. Inhibition of protein kinase A (PKA), protein kinase C (PKC) and, Ca2+/calmodulin-dependent protein kinase II (CaMKII), but not phosphoinositide 3-kinase(PI3K), by using the pharmacological the inhibitors: H-89, chelerythrine, KN-62, and LY294002, respectively totally abolished the cytoprotective effects of UA. Finally, UA abrogated the reduction in phospho-extracellular signal-regulated kinases 1 and 2 (ERK1/2) but not in phospho-c-Jun kinases induced by corticosterone. These results indicate that the protective effect of UA against the cytotoxicity induced by corticosterone in HT22 cells may involve PKA, PKC, CaMKII, and ERK1/2 activation. The cytoprotective potential of UA against corticosterone-induced cytotoxicity and its ability to modulate intracellular signaling pathways involved in cell proliferation and survival suggest that UA may be a relevant strategy to manage stress-related disorders such as MDD.

RESUMEN

Although guanosine is an endogenous nucleoside that displays antidepressant-like properties in several animal models, the mechanism underlying its antidepressant-like effects is not well characterized. The present study aimed at investigating the involvement of ERK/GSK-3ß and Nrf2/HO-1 signaling pathways in the antidepressant-like effect of guanosine in the mouse tail suspension test (TST). The immobility time in the TST was taken as an indicative of antidepressant-like responses and the locomotor activity was assessed in the open-field test. Biochemical analyses were performed by Western blotting in the hippocampus and prefrontal cortex (PFC). The combined treatment with sub-effective doses of guanosine (0.01 mg/kg, p.o.) and lithium chloride (a non-selective GSK-3ß inhibitor, 10 mg/kg, p.o.) or AR-A014418 (selective GSK-3ß inhibitor, 0.01 µg/site, i.c.v.) produced a synergistic antidepressant-like effect in the TST. The antidepressant-like effect of guanosine (0.05 mg/kg, p.o.) was completely prevented by the treatment with MEK1/2 inhibitors U0126 (5 µg/site, i.c.v.), PD98059 (5 µg/site, i.c.v.), or zinc protoporphyrin IX (ZnPP) (HO-1 inhibitor, 10 µg/site, i.c.v). Guanosine administration (0.05 mg/kg, p.o.) increased the immunocontent of ß-catenin in the nuclear fraction and Nrf2 in the cytosolic fraction in the hippocampus and PFC. The immunocontent of HO-1 was also increased in the hippocampus and PFC. Altogether, the results provide evidence that the antidepressant-like effect of guanosine in the TST involves the inhibition of GSK-3ß, as well as activation of MAPK/ERK and Nrf2/HO-1 signaling pathways, highlighting the relevance of these molecular targets for antidepressant responses.

Asunto(s)

Glucógeno Sintasa Quinasa 3 beta/efectos de los fármacos , Guanosina/farmacología , Hemo-Oxigenasa 1/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Animales , Antidepresivos/farmacología , Depresión/tratamiento farmacológico , Depresión/metabolismo , Modelos Animales de Enfermedad , Conducta Exploratoria/efectos de los fármacos , Femenino , Hemo-Oxigenasa 1/metabolismo , Suspensión Trasera/métodos , Hipocampo/metabolismo , Masculino , Ratas Wistar , Transducción de Señal/fisiología

RESUMEN

The antitumor activity of DVL, a lectin purified from Dioclea violacea seeds, on the U87 human glioma cell line was evaluated and compared with Canavalia ensiformis lectin (ConA). Treatment with DVL (10-100 µg/mL; 24-96 h) induced alterations in cell morphology, decreased cell numbers and clonogenic survival in a time- and concentration-dependent manner. DVL caused significant decreases in cell viability and impaired cell migration. Mechanistically, DVL treatment (12 h) disrupted mitochondrial electrochemical gradient, without ROS accumulation or caspase activation. In the absence of apoptosis, DVL (30-100 µg/mL), instead, induced autophagy, as detected by acridine orange staining and cleavage of LC3I. Inhibition of autophagy with 3-Methyladenine (3-MA) and Chloroquine partially abrogated DVL, but not ConA, cytotoxicity. The modulation of signaling pathways that orchestrate autophagic and cell survival processes were analyzed. DVL (30-100 µg/mL) decreased Akt, mTORC1 and ERK1/2 phosphorylation and augmented JNK(p54) and p38MAPK phosphorylation. DVL was more potent than ConA for most parameters analyzed. Even though both lectins showed cytotoxicity to glioma cells, they spared primary astrocyte cultures. The results suggest a selective antiglioma activity of DVL by inhibiting U87 glioma cell migration and proliferation and inducing cell death, partially associated with autophagy, and likely involving Akt and mTORC1 dephosphorylation.

Asunto(s)

Autofagia/efectos de los fármacos , Dioclea/química , Lectinas de Plantas/farmacología , Animales , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Caspasa 3/metabolismo , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Glioma/genética , Glioma/metabolismo , Humanos , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Mitocondrias/metabolismo , Lectinas de Plantas/química , Lectinas de Plantas/aislamiento & purificación , Ratas , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal/efectos de los fármacos

RESUMEN

Plant lectins have been studied owing to their structural properties and biological effects that include agglutinating activity, antidepressant-like effect and antitumor property. The results from this work showed the effects of the lectin extracted from the Dioclea violacea plant (DVL) on the C6 rat glioma cell line. DVL treatment was able to induce caspase-3 activation, apoptotic cell death and cellular membrane damage. Furthermore, DVL decreased mitochondrial membrane potential and increased the number of acidic vesicles and cleavage of LC3, indicating activation of autophagic processes. DVL also significantly inhibited cell migration. Compared to ConA, a well-studied lectin extracted from Canavalia ensiformes seeds, some effects of DVL were more potent, including decreasing C6 glioma cell viability and migration ability. Taken together, the results suggest that DVL can induce glioma cell death, autophagy and inhibition of cell migration, displaying potential anti-glioma activity.

Asunto(s)

Autofagia/efectos de los fármacos , Dioclea/química , Expresión Génica/efectos de los fármacos , Neuroglía/efectos de los fármacos , Lectinas de Plantas/farmacología , Animales , Apoptosis/efectos de los fármacos , Apoptosis/genética , Autofagia/genética , Canavalia/química , Caspasa 3/genética , Caspasa 3/metabolismo , Ciclo Celular/efectos de los fármacos , Ciclo Celular/genética , Línea Celular Tumoral , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Membrana Celular/ultraestructura , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Concanavalina A/aislamiento & purificación , Concanavalina A/farmacología , L-Lactato Deshidrogenasa/metabolismo , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Neuroglía/metabolismo , Neuroglía/patología , Lectinas de Plantas/aislamiento & purificación , Ratas

RESUMEN

Agmatine is a neuromodulator that has been proposed as a therapeutic strategy for the treatment of major depressive disorder (MDD). A previous study reported that agmatine caused a fast-acting effect in mice subjected to chronic mild stress without causing changes in the levels of synaptic proteins in the prefrontal cortex. We examined whether a single administration of agmatine is able to counteract the depressive-like behavior induced by chronic administration of corticosterone, a pharmacological model of stress, paralleled with the modulation of synaptic protein levels in the prefrontal cortex and hippocampus. Female mice received corticosterone (20 mg/kg, p.o.) for 21 days and, in the last day of treatment, were administered with a single dose of agmatine (0.1 mg/kg, p.o.), fluoxetine (10 mg/kg, p.o.; control for a conventional antidepressant) or ketamine (1 mg/kg, i.p.; control for a fast-acting antidepressant). Agmatine, similar to ketamine, reversed the depressive-like behavior induced by corticosterone in the tail suspension test (TST), an effect that was not observed in mice treated with fluoxetine. The immunocontent of GluA1 was increased by all the treatments in the hippocampus of control mice, whereas PSD95 was not significantly altered by treatments in any brain structure. Although the levels of synaptic proteins do not seem to account for the behavioral findings reported here, the present study provides clear evidence for the fast-acting antidepressant profile of agmatine in the TST, similar to ketamine.

Asunto(s)

Agmatina/administración & dosificación , Antidepresivos/farmacología , Corticosterona/farmacología , Depresión/inducido químicamente , Depresión/prevención & control , Antagonistas de Aminoácidos Excitadores/farmacología , Fluoxetina/farmacología , Ketamina/farmacología , Animales , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Homólogo 4 de la Proteína Discs Large/metabolismo , Femenino , Ratones , Receptores AMPA/metabolismo

RESUMEN

Excessive levels of the essential metal manganese (Mn) may cause a syndrome similar to Parkinson's disease. The model organism Caenorhabditis elegans mimics some of Mn effects in mammals, including dopaminergic neurodegeneration, oxidative stress, and increased levels of AKT. The evolutionarily conserved insulin/insulin-like growth factor-1 signaling pathway (IIS) modulates worm longevity, metabolism, and antioxidant responses by antagonizing the transcription factors DAF-16/FOXO and SKN-1/Nrf-2. AKT-1, AKT-2, and SGK-1 act upstream of these transcription factors. To study the role of these proteins in C. elegans response to Mn intoxication, wild-type N2 and loss-of-function mutants were exposed to Mn (2.5 to 100 mM) for 1 h at the L1 larval stage. Strains with loss-of-function in akt-1, akt-2, and sgk-1 had higher resistance to Mn compared to N2 in the survival test. All strains tested accumulated Mn similarly, as shown by ICP-MS. DAF-16 nuclear translocation was observed by fluorescence microscopy in WT and loss-of-function strains exposed to Mn. qRT-PCR data indicate increased expression of γ-glutamyl cysteine synthetase (GCS-1) antioxidant enzyme in akt-1 mutants. The expression of sod-3 (superoxide dismutase homologue) was increased in the akt-1 mutant worms, independent of Mn treatment. However, dopaminergic neurons degenerated even in the more resistant strains. Dopaminergic function was evaluated with the basal slowing response behavioral test and dopaminergic neuron integrity was evaluated using worms expressing green fluorescent protein (GFP) under the dopamine transporter (DAT-1) promoter. These results suggest that AKT-1/2 and SGK-1 play a role in C. elegans response to Mn intoxication. However, tissue-specific responses may occur in dopaminergic neurons, contributing to degeneration.

Asunto(s)

Proteínas de Caenorhabditis elegans/metabolismo , Cloruros/toxicidad , Intoxicación por Manganeso/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transporte Activo de Núcleo Celular/efectos de los fármacos , Transporte Activo de Núcleo Celular/genética , Animales , Animales Modificados Genéticamente , Conducta Animal/fisiología , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/genética , Modelos Animales de Enfermedad , Dopamina/metabolismo , Factores de Transcripción Forkhead/metabolismo , Glutatión/metabolismo , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Compuestos de Manganeso , Intoxicación por Manganeso/complicaciones , Intoxicación por Manganeso/patología , Mutación/genética , Degeneración Nerviosa/etiología , Degeneración Nerviosa/patología , Proteínas Serina-Treonina Quinasas/genética , Proteínas Proto-Oncogénicas c-akt/genética , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo

RESUMEN

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is one of the most robust neurobiological findings in the pathophysiology of major depressive disorder (MDD) over the last 40 years. The persistent increase in glucocorticoids levels induces morphological and anatomical changes in the brain, especially in the hippocampus. Ketamine represents a major advance for the treatment of MDD, however the psychotomimetic effects of this compound limit its widespread use. Agmatine is a neuromodulator that has been shown to be a putative novel and well-tolerated antidepressant/augmenter drug. In this study, the exposure of HT22 hippocampal neuronal cell line to corticosterone (50 µM) induced a significant neuronal cell death. Interestingly, the incubation of HT22 cells with the fast-acting antidepressant drug ketamine (1 µM) prevented the corticosterone-induced toxicity. Similarly, agmatine caused a significant cytoprotection at the concentration of 0.1 µM against corticosterone (50 µM) cell damage. Notably, the incubation with a subthreshold concentration of ketamine (0.01 µM) in combination with a subthreshold concentration of agmatine (0.001 µM) prevented the neuronal damage elicited by corticosterone (50 µM). A 24 h co-incubation with subthreshold concentrations of ketamine (0.01 µM) and agmatine (0.001 µM) was able to cause a significant increase in the phosphorylation levels of Akt (Ser473) and p70S6 kinase (Thr389) as well as PSD95 immunocontent. Neither glycogen synthase kinase-3ß (Ser9) phosphorylation nor ß catenin immunocontent were altered by a 24 h co-incubation period. Finally, the co-incubation of cells for 30 min did not produce any effect in the phosphorylation or immunocontent of any protein investigated. Taken together, our results support the notion that the combination of subthreshold concentrations of ketamine and agmatine has cytoprotective effects against corticosterone-induced cell death. This effect is accompanied by its ability to activate Akt and mTOR/S6 kinase signaling pathway, and increase the expression of synaptic proteins.

Asunto(s)

Agmatina/administración & dosificación , Ketamina/administración & dosificación , Fármacos Neuroprotectores/administración & dosificación , Proteínas Quinasas S6 Ribosómicas/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , Analgésicos/administración & dosificación , Animales , Muerte Celular/efectos de los fármacos , Muerte Celular/fisiología , Línea Celular Transformada , Corticosterona/toxicidad , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Ratones , Transducción de Señal/efectos de los fármacos

RESUMEN

N-methyl D-aspartate (NMDA) preconditioning is evoked by the administration of a subtoxic dose of NMDA and is protective against neuronal excitotoxicity. This effect may involve a diversity of targets and cell signaling cascades associated to neuroprotection. Phosphatidylinositol-3 kinase/protein kinase B (PI3K/Akt) and mitogen-activated protein kinases (MAPKs) such as extracellular regulated protein kinase 1/2 (ERK1/2) and p38MAPK pathways play a major role in neuroprotective mechanisms. However, their involvement in NMDA preconditioning was not yet fully investigated. The present study aimed to evaluate the effect of NMDA preconditioning on PI3K/Akt, ERK1/2, and p38MAPK pathways in the hippocampus of mice and characterize the involvement of PI3K on NMDA preconditioning-evoked prevention of seizures and hippocampal cell damage induced by quinolinic acid (QA). Thus, mice received wortmannin (a PI3K inhibitor) and 15 min later a subconvulsant dose of NMDA (preconditioning) or saline. After 24 h of this treatment, an intracerebroventricular QA infusion was administered. Phosphorylation levels and total content of Akt, glycogen synthase protein kinase-3ß (GSK-3ß), ERK1/2, and p38MAPK were not altered after 24 h of NMDA preconditioning with or without wortmmanin pretreatment. Moreover, after QA administration, behavioral seizures, hippocampal neuronal degeneration, and Akt activation were evaluated. Inhibition of PI3K pathway was effective in abolishing the protective effect of NMDA preconditioning against QA-induced seizures, but did not modify neuronal protection promoted by preconditioning as evaluated by Fluoro-Jade B staining. The study confirms that PI3K participates in the mechanism of protection induced by NMDA preconditioning against QA-induced seizures. Conversely, NMDA preconditioning-evoked protection against neuronal degeneration is not altered by PI3K signaling pathway inhibition. These results point to differential mechanisms regarding protection against a behavioral and cellular manifestation of neural damage.

Asunto(s)

Agonistas de Aminoácidos Excitadores/administración & dosificación , Hipocampo/patología , N-Metilaspartato/administración & dosificación , Enfermedades Neurodegenerativas/inducido químicamente , Fosfatidilinositol 3-Quinasa/metabolismo , Ácido Quinolínico/toxicidad , Transducción de Señal/efectos de los fármacos , Animales , Modelos Animales de Enfermedad , Esquema de Medicación , Inhibidores Enzimáticos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Masculino , Ratones , Enfermedades Neurodegenerativas/patología , Neuronas/efectos de los fármacos , Neuronas/patología , Factores de Tiempo

RESUMEN

Agmatine is an endogenous neuromodulator that has been shown to have antidepressant-like properties. We have previously demonstrated that it can induce a rapid increase in BDNF levels after acute administration, suggesting that agmatine may be a fast-acting antidepressant. To investigate this hypothesis, the present study evaluated the effects of a single administration of agmatine in mice subjected to chronic unpredictable stress (CUS), a model of depression responsive only to chronic treatment with conventional antidepressants. The ability of agmatine to reverse CUS-induced behavioral and biochemical alterations was evaluated and compared with those elicited by the fast-acting antidepressant (ketamine) and the conventional antidepressant (fluoxetine). After exposed to CUS for 14days, mice received a single oral dose of agmatine (0.1mg/kg), ketamine (1mg/kg) or fluoxetine (10mg/kg), and were submitted to behavioral evaluation after 24h. The exposure to CUS caused an increased immobility time in the tail suspension test (TST) but did not change anhedonic-related parameters in the splash test. Our findings provided evidence that, similarly to ketamine, agmatine is able to reverse CUS-induced depressive-like behavior in the TST. Western blot analyses of prefrontal cortex (PFC) demonstrated that mice exposed to CUS and/or treated with agmatine, fluoxetine or ketamine did not present alterations in the immunocontent of synaptic proteins [i.e. GluA1, postsynaptic density protein 95 (PSD-95) and synapsin]. Altogether, our findings indicate that a single administration of agmatine is able to reverse behavioral alterations induced by CUS in the TST, suggesting that this compound may have fast-acting antidepressant-like properties. However, there was no alteration in the levels of synaptic proteins in the PFC, a result that need to be further investigated in other time points.

Asunto(s)

Agmatina/farmacología , Antidepresivos/farmacología , Trastorno Depresivo/tratamiento farmacológico , Ketamina/farmacología , Estrés Psicológico/complicaciones , Animales , Femenino , Suspensión Trasera , Ratones , Actividad Motora/efectos de los fármacos , Corteza Prefrontal/química

RESUMEN

Carboxypeptidase A6 (CPA6) is an extracellular matrix metallocarboxypeptidase that modulates peptide and protein function by removal of hydrophobic C-terminal amino acids. Mutations in the human CPA6 gene that reduce enzymatic activity in the extracellular matrix are associated with febrile seizures, temporal lobe epilepsy, and juvenile myoclonic epilepsy. The characterization of these human mutations suggests a dominant mode of inheritance by haploinsufficiency through loss of function mutations, however the total number of humans with pathologic mutations in CPA6 identified to date remains small. To better understand the relationship between CPA6 and seizures we investigated the effects of morpholino knockdown of cpa6 mRNA in zebrafish (Danio rerio) larvae. Knockdown of cpa6 mRNA resulted in resistance to the effect of seizure-inducing drugs pentylenetetrazole and pilocarpine on swimming behaviors. Knockdown of cpa6 mRNA also reduced the levels of mRNAs encoding neuropeptide precursors (bdnf, npy, chga, pcsk1nl, tac1, nts, edn1), a neuropeptide processing enzyme (cpe), transcription factor (c-fos), and molecules implicated in glutamatergic signaling (grin1a and slc1a2b). Treatment of zebrafish embryos with 60 mM pilocarpine for 1 hour led to reductions in levels of many of the same mRNAs when measured 1 day after pilocarpine exposure, except for c-fos which was elevated 1 day after pilocarpine treatment. Pilocarpine treatment, like cpa6 knockdown, led to a reduced sensitivity to pentylenetetrazole when tested 1 day after pilocarpine treatment. Taken together, these results add to mounting evidence that peptidergic systems participate in the biological effects of seizure-inducing drugs, and are the first in vivo demonstration of the molecular and behavioral consequences of cpa6 insufficiency.

Asunto(s)

Carboxipeptidasas A/genética , Técnicas de Silenciamiento del Gen , Larva/enzimología , Proteínas de Pez Cebra/genética , Pez Cebra/crecimiento & desarrollo , Animales , Convulsivantes/administración & dosificación , Mutación , Pilocarpina/administración & dosificación , ARN Mensajero/genética , Transcripción Genética , Pez Cebra/embriología

RESUMEN

Manganese (Mn) is an essential trace element required for a range of physiological processes, but Mn can also be neurotoxic especially during development. Excess levels of Mn accumulate preferentially in the striatum and can induce a syndrome called manganism, characterized by an initial stage of psychiatric disorder followed by motor impairment. In the present study, we investigated the effects of Mn exposure on the developing dopaminergic system, specifically tyrosine hydroxylase (TH) protein and phosphorylation levels in the striatum of rats. Neonatal rats were exposed to Mn intraperitoneally (ip) from post-natal day 8 up to day 12 (PND8-12). Striatal tissue was analysed on PND14 or PND70, to detect either short-term or long-term effects induced by Mn exposure. There was a dose dependent increase in TH protein levels in the striatum at PND14, reaching significance at 20 mg kg(-1) Mn, and this correlated with an increase in TH phosphorylation at serines 40, 31 and 19. However, in the striatum at PND70, a time by which Mn levels were no longer elevated, there was a dose dependent decrease in TH protein levels, reaching significance at 20 mg kg(-1) Mn, and this correlated with TH phosphorylation at Ser40 and Ser19. There was however a significant increase in phosphorylation of TH at serine 31 at 20 mg kg(-1) Mn, which did not correlate with TH protein levels. Taken together our findings suggest that neonatal Mn exposure can have both short-term and long-term effects on the regulation of TH in the striatal dopaminergic system.

Asunto(s)

Cuerpo Estriado/enzimología , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Manganeso/farmacología , Tirosina 3-Monooxigenasa/metabolismo , Animales , Animales Recién Nacidos , Cuerpo Estriado/efectos de los fármacos , Masculino , Fosforilación/efectos de los fármacos , Ratas , Ratas Wistar , Tirosina 3-Monooxigenasa/genética

RESUMEN

Creatine has been proposed to exert beneficial effects in the management of depression, but the cell signaling pathways implicated in its antidepressant effects are not well established. This study investigated the involvement of PI3K/Akt signaling pathway and its downstream intracellular targets in the antidepressant-like effect of creatine. The acute treatment of mice with creatine (1 mg/kg, po) increased the Akt and P70S6K phosphorylation, and HO-1, GPx and PSD95 immunocontents. The pretreatment of mice with LY294002 (10 nmol/mouse, icv, PI3K inhibitor), wortmannin (0.1 µg/mouse, icv, PI3K inhibitor), ZnPP (10 µg/mouse, icv, HO-1 inhibitor), or rapamycin (0.2 nmol/mouse, icv, mTOR inhibitor) prevented the antidepressant-like effect of creatine (1 mg/kg, po) in the TST. In addition, the administration of subeffective dose of either the selective GSK3 inhibitor AR-A014418 (0.01 µg/mouse, icv), the nonselective GSK3 inhibitor lithium chloride (10 mg/kg, po), or the HO-1 inductor CoPP (0.01 µg/mouse, icv), in combination with a subeffective dose of creatine (0.01 mg/kg, po) reduced the immobility time in the TST as compared with either drug alone. No treatment caused significant changes in the locomotor activity of mice. These results indicate that the antidepressant-like effect of creatine in the TST depends on the activation of Akt, Nrf2/HO-1, GPx, and mTOR, and GSK3 inhibition.

Asunto(s)

Antidepresivos/farmacología , Creatina/farmacología , Espacio Intracelular/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal , Animales , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Homólogo 4 de la Proteína Discs Large/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Glucógeno Sintasa Quinasa 3/antagonistas & inhibidores , Glucógeno Sintasa Quinasa 3/metabolismo , Hemo-Oxigenasa 1/metabolismo , Hipocampo/metabolismo , Masculino , Ratones , Fosforilación/efectos de los fármacos , Proteína Quinasa C/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas S6 Ribosómicas 70-kDa/metabolismo , Transducción de Señal/efectos de los fármacos , Especificidad por Sustrato/efectos de los fármacos , Serina-Treonina Quinasas TOR/metabolismo