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1.
Biotechnol Rep (Amst) ; 41: e00821, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38173966

ABSTRACT

Cell models are indispensable tools in biotechnology when investigating the functional properties of organic compounds. The emergence of various additives designed to enhance animal production has introduced the need for in-depth evaluations, which are often hindered by the complexities of in vivo testing. In this study, we harnessed cell-based models to scrutinize the impact of Solergy as a regulator of cellular metabolism with a particular focus on its modulation of glycogen and antioxidant effects. Our experiment was designed to include assessments of the influence of Solergy on the viability of both terrestrial and aquatic vertebrate cell models, which revealed the benign nature of Solergy and its lack of adverse effects. Furthermore, we examined the capacity of Solergy to modulate intracellular ATP concentrations and enhance glycogen accumulation. Notably, the antioxidant potential of Solergy and its ability to mitigate cellular aging were evaluated within the same cellular frameworks. The outcomes of our investigation suggest that Solergy is a potent metabolic regulator that elevates cellular activity while exerting an antioxidant effect. Importantly, our study demonstrates that Solergy does not induce changes in membrane oxidation. These findings indicate the potential of using Solergy to regulate glycogen synthesis, intracellular ATP concentrations, and oxidative stress in production animals. The multifaceted effects of this additive, which acts as both a metabolism enhancer and an antioxidant, open doors to the creation of custom diets tailored to meet specific production needs while maintaining stable production parameters.

2.
Mater Sci Eng C Mater Biol Appl ; 116: 111183, 2020 Nov.
Article in English | MEDLINE | ID: mdl-32806315

ABSTRACT

In the present work, the fabrication of hybrid porous silicon/green synthetized Ag microparticles was shown and the potential use as carriers for Ag nanoparticles and drug delivery was explored. Hybrid microparticles were fabricated by incorporating green synthetized Ag nanoparticles into porous silicon matrix. The main physicochemical characteristics of the hybrid systems were studied by several techniques including UV-vis spectroscopy, TEM, SEM, XRD and XPS. The toxicology of these hybrid systems was investigated by cell viability, MTT, and comet assays. In addition, the possibility to aggregate different drug to use as drug delivery system was demonstrated by using florfenicol as drug model, due to its importance in salmon industry. The experimental results showed the potential to use these hybrid systems as carries for drug delivery in salmon industry.


Subject(s)
Metal Nanoparticles , Pharmaceutical Preparations , Porosity , Silicon , Silver
4.
Fish Physiol Biochem ; 46(3): 945-952, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32350676

ABSTRACT

The use of additives in the feed industry for producing fish has become the focus of constant change and research. The formulation of a product as a feeding strategy leads to the use of more than one molecule with particular characteristics to seek a synergistic effect when they are administered in the food. The application of taurine and silymarin in the salmon farming industry needs the exploration of the synergistic effects. For this study, we evaluated the effects of various concentrations of additives in the cell line CHSE-214 of Oncorhynchus tshawytscha. The cells were exposed to increasing concentrations of hydrogen peroxide as an oxidizing agent and were then given treatments of taurine, silymarin or both additives together. Our results indicate that the molecules had separate antioxidant effects, and the taurine treatment reached the highest number of cells per area at a dose of 100 ppm. However, if the cells were treated together at 100 ppm, silymarin achieved outstanding effects. However, when the treatment with both molecules was increased to 500 ppm of taurine, the effect was blocked, and the treatment acted as an antagonist. Our data indicate that the formulation of diets must be rigorously carried out, especially for determining the doses to be used to generate synergy among antioxidant additives and to reduce the effect of antagonism between the additives. Likewise, the use of cell lines is a strategy to evaluate the mechanisms of action for additives that are used in the development of diets for the salmon industry.


Subject(s)
Antioxidants/pharmacology , Dietary Supplements , Silymarin/pharmacology , Taurine/pharmacology , Animals , Aquaculture/methods , Cell Line , Cell Survival/drug effects , Hydrogen Peroxide/toxicity , Salmon
5.
Aquat Toxicol ; 211: 141-147, 2019 Jun.
Article in English | MEDLINE | ID: mdl-30981037

ABSTRACT

Didymosphenia geminata (Lyngbye) Schmidt, also referred to as Didymo, is an invasive diatom that forms nuisance mats. Since it was first reported in our country in approximately 2010, Didymo has expanded and colonized different rivers in the Zona Austral region of Chile. Its biology and effects on ecosystems are still being studied because Didymo is an invasive algal mat that forms in a range of systems from oligotrophic austral rivers to more subtropical systems. We aimed to evaluate the viability of two salmonid cell lines, CHSE-214 and SHK-1 (somatic and embryonic cell lines, respectively), in dilutions of river water alone and in river water contaminated with Didymo or polyphenols extracted from Didymo under controlled conditions. We developed an artificial river system (2 aquariums/replicate) from five different rivers from the central area (Bio-Bio) and Patagonia area (Futaleufú) of Chile to maintain Didymo in the benthic phase. The Didymo populations were maintained for six months in the water from the rivers, after which samples were obtained. Following the extraction of polyphenols from the Didymo samples maintained in the artificial rivers, toxicity assays (10 assays) were performed to determine cell viability. Our results indicated that the CHSE-214 cells were highly sensitive to increasing concentrations of Didymo extracts. We observed a 50% reduction in cell viability after 24 h of exposure to a 0.01 V/V dilution, and this treatment further reduced the proliferative capacity by 70% after 120 h. The SHK-1 cells were less responsive, showing only a 20% decrease in viability at 24 h and a lower cell proliferation rate (45%) after 120 h, which remained higher than that of the CHSE-214 cells. We conclude that certain cell types are sensitive to Didymo in rivers, suggesting that there are chronic effects on several aquatic species following exposure to these diatom substances. These effects should be further studied using this laboratory model to understand the full impact of Didymo on river ecosystems.


Subject(s)
Cell Proliferation/drug effects , Diatoms/chemistry , Introduced Species , Polyphenols/toxicity , Salmonidae , Water Pollutants, Chemical/toxicity , Animals , Cell Line , Cell Survival/drug effects , Chile , Ecosystem , Models, Theoretical , Polyphenols/isolation & purification , Rivers/chemistry , Water Pollutants, Chemical/isolation & purification
6.
PeerJ ; 7: e6481, 2019.
Article in English | MEDLINE | ID: mdl-30805252

ABSTRACT

Didymosphenia geminata is a diatom that can alter aquatic systems. Several investigations have shown as chemical, and hydraulic factors have a great influence on the proliferation of D. geminata, but the study of other microalgae that could be associated with it has been poorly addressed. The objective of this study is to evaluate the relationship between mat thickness, D. geminata and another taxon that produces mucilage, Cymbella, while also considering physical and chemical factors. For this, two samples were taken, one in the spring of 2013 and the other in the autumn of 2014, from eight rivers in central-southern Chile-South America, where the benthic community was characterized, and the thickness of the mat was measured. The results show that the mat thickness on sites with the presence of both taxa is doubled, and while sites with D. geminata presence showed mat peak on autumn, sites with Cymbella spp. presence showed on spring. Also, higher values of mat thickness associated with low cell densities of D. geminata and intermediate cell densities of Cymbella spp. Finally, physicochemical variables that better explain mat thickness are phosphorus and water temperature. An alternation process of mucilage production may explain these results by these taxa strongly related to physicochemical variables. The present study contributes evidence about the relationship between mat thickness D. geminata and other microalgae contribution, and aquatic condition for this development.

7.
J Toxicol Environ Health A ; 80(4): 208-217, 2017.
Article in English | MEDLINE | ID: mdl-28304234

ABSTRACT

Peumus boldus Mol. ("Boldo") and Cryptocarya alba Mol. Looser ("Peumo") are medicinal shrubs with wide geographical distribution in South America. Their leaves and fruits are commonly used in traditional medicine because they exhibit natural medicinal properties for treatment of liver disorders and rheumatism. However, there are no apparent data regarding potential protective effects on cellular genetic components. In order to examine potential mutagenic and/or antimutagenic effects of these medicinal plants, the Drosophila melanogaster (D. melanogaster) wing-spot test was employed. This assay detects a wide range of mutational events, including point mutations, deletions, certain types of chromosomal aberrations (nondisjunction), and mitotic recombination. Qualitative and quantitative analyses of phenolic and anthocyanin compounds were carried out using biochemical and high-performance liquid chromatography methodologies. In addition, the antioxidant capacity of P. boldus and C. alba leaf extracts was also analyzed. P. boldus and C. alba extracts did not induce significant mutagenic effects in the D. melanogaster model. However, simultaneous treatment of extracts concurrently with the mutagen ethyl methane sulphonate showed a decrease of mutant spots in somatic cells of D. melanogaster, indicating desmutagenic effects in this in vivo model. Flavonoids and anthocyanins were detected predominantly in the extracts, and these compounds exerted significant antioxidant capacity. The observed antimutagenic effects may be related to the presence of phytochemicals with high antioxidant capacity, such as flavonoids and antohocyanins, in the extracts.


Subject(s)
Antimutagenic Agents/pharmacology , Cryptocarya/chemistry , Drosophila melanogaster/drug effects , Peumus/chemistry , Plants, Medicinal/chemistry , Animals , Anthocyanins/analysis , Anthocyanins/pharmacology , Antioxidants/analysis , Antioxidants/pharmacology , Chile , Drosophila melanogaster/growth & development , Ethyl Methanesulfonate/metabolism , Larva/drug effects , Mutagens/metabolism , Phenols/analysis , Phenols/pharmacology , Plant Extracts/chemistry , Plant Leaves/chemistry , Wings, Animal/drug effects
8.
Mol Cell Neurosci ; 68: 314-22, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26311509

ABSTRACT

Hippocampal synapses play a key role in memory and learning processes by inducing long-term potentiation and depression. Wnt signaling is essential in the development and maintenance of synapses via several mechanisms. We have previously found that Wnt5a induces the production of nitric oxide (NO), which modulates NMDA receptor expression in the postsynaptic regions of hippocampal neurons. Here, we report that Wnt5a selectively inhibits a voltage-gated K(+) current (Kv current) and increases synaptic activity in hippocampal slices. Further supporting a specific role for Wnt5a, the soluble Frizzled receptor protein (sFRP-2; a functional Wnt antagonist) fully inhibits the effects of Wnt5a. We additionally show that these responses to Wnt5a are mediated by activation of a ROR2 receptor and increased NO production because they are suppressed by the shRNA-mediated knockdown of ROR2 and by 7-nitroindazole, a specific inhibitor of neuronal NOS. Together, our results show that Wnt5a increases NO production by acting on ROR2 receptors, which in turn inhibit Kv currents. These results reveal a novel mechanism by which Wnt5a may regulate the excitability of hippocampal neurons.


Subject(s)
Hippocampus/cytology , Neurons/physiology , Nitric Oxide/metabolism , Potassium Channels/physiology , Synapses/physiology , Wnt Proteins/physiology , Animals , Cells, Cultured , Embryo, Mammalian , Enzyme Inhibitors/pharmacology , Excitatory Postsynaptic Potentials/drug effects , Excitatory Postsynaptic Potentials/genetics , In Vitro Techniques , Indazoles/pharmacology , Mice , Mice, Inbred C57BL , Potassium/pharmacology , Rats , Rats, Sprague-Dawley , Receptor Tyrosine Kinase-like Orphan Receptors/genetics , Receptor Tyrosine Kinase-like Orphan Receptors/metabolism , Transduction, Genetic , Wnt-5a Protein , omega-N-Methylarginine/pharmacology
9.
Aquat Toxicol ; 163: 102-8, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25885475

ABSTRACT

Didimosphenia geminata ("didymo"), has become a powerful and devastating river plague in Chile. A system was developed in D. geminata channels with the purpose evaluating the effects of water polluted with didymo on the activation of Atlantic salmon (Salmo salar) spermatozoa. Results indicate that semen, when activated with uncontaminated river water had an average time of 60±21s. When using Powermilt, (a commercial activator), times of 240±21s are achieved, while rivers contaminated with D. geminata achieve a motility time of 30±12s. Interestingly enough, the kinetic parameters of VSL, VCL and VAP showed no significant changes under all of the conditions. Furthermore, the presence of D. geminata reduces activation time of the samples as the cells age, indicating increased effects in spermatozoa that are conserved for more than 5 days. D. geminata has antioxidant content, represented by polyphenols; 200ppm of polyphenol were obtained in this study per 10g of microalgae. Spermatozoa exposed to these extracts showed a reduction in mobility time in a dose dependent manner, showing an IC50 of 15ppm. The results suggest an effect on spermatozoa activation, possibly due to the release of polyphenols present in contaminated rivers, facilitating the alteration of sperm motility times, without affecting the viability or kinetics of the cells. These findings have important implications for current policy regarding the control of the algae. Current control measures focus on the number of visible species, and not on the compounds that they release, which this study shows, also have a problematic effect on salmon production.


Subject(s)
Diatoms/metabolism , Fresh Water/chemistry , Salmo salar/physiology , Spermatozoa/physiology , Animals , Antioxidants/metabolism , Antioxidants/pharmacology , Diatoms/chemistry , Male , Microscopy, Confocal , Polyphenols/metabolism , Polyphenols/pharmacology , Rivers/chemistry , Sperm Motility/drug effects , Sperm Motility/physiology , Spermatozoa/drug effects
10.
Arthritis Rheumatol ; 67(6): 1598-610, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25709106

ABSTRACT

OBJECTIVE: To assess whether autoantibodies against ribosomal P (anti-P), which are possibly pathogenic in neuropsychiatric systemic lupus erythematosus (NPSLE), alter glutamatergic synaptic transmission and to what extent the cross-reacting neuronal surface P antigen (NSPA) is involved. METHODS: We analyzed glutamatergic transmission and long-term potentiation (LTP) mediated by AMPA receptor (AMPAR) and N-methyl-d-aspartate receptor (NMDAR) by field excitatory postsynaptic potential (EPSP) at the CA3-CA1 synapse. AMPAR activation by patch-clamp recordings in primary ventral spinal cord neurons was analyzed. In primary hippocampal neurons, NSPA distribution was assessed by double immunofluorescence, and intracellular calcium changes were evaluated using Fura-2 AM. NSPA-LacZ reporter-knockin mice expressing a truncated NSPA were used to assess NSPA expression pattern and function in the brain using ß-galactosidase staining and comparative electrophysiology, calcium responses, and water maze memory tests. RESULTS: NSPA was expressed in the brain in hippocampal CA1, dentate gyrus and ventral, but not dorsal, CA3 regions, encompassing postsynaptic regions and partial colocalization with NMDAR. Notably, NSPA-LacZ reporter-knockin mice showed impaired memory, and decreased NMDAR activity and LTP, with neurons insensitive to anti-P autoantibodies. Anti-P autoantibodies enhanced CA1 postsynaptic transmission, increasing AMPAR and NMDAR activity and leading to LTP abrogation after prolonged (20-minute) incubation. CONCLUSION: Our findings indicate that the neuronal cell surface target of anti-P, NSPA, is involved in glutamatergic synaptic transmission and plasticity related to memory in the hippocampus, and mediates the deleterious effects of anti-P on these processes. Cognitive impairment, as well as other diffuse NPSLE manifestations, may develop when anti-P autoantibodies have access to brain regions coexpressing NSPA, AMPAR, and NMDAR.


Subject(s)
Autoantibodies/immunology , Hippocampus/metabolism , Long-Term Potentiation , Lupus Erythematosus, Systemic/immunology , Neurons/metabolism , Ribosomal Proteins/immunology , Synaptic Transmission , Adult , Animals , Antigens, Surface , CA1 Region, Hippocampal/metabolism , CA3 Region, Hippocampal/metabolism , Dentate Gyrus/metabolism , Disease Models, Animal , Excitatory Postsynaptic Potentials , Female , Gene Knock-In Techniques , Glutamic Acid/metabolism , Humans , Lupus Erythematosus, Systemic/metabolism , Memory , Mice , Neuronal Plasticity , Neurons/immunology , Patch-Clamp Techniques , Receptors, AMPA/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Ribosomal Proteins/metabolism , Spinal Cord/cytology , Young Adult
11.
BMB Rep ; 48(1): 13-8, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25047445

ABSTRACT

Alzheimer's disease severely compromises cognitive function. One of the mechanisms to explain the pathology of Alzheimer's disease has been the hypotheses of amyloid-pore/channel formation by complex Aß-aggregates. Clinical studies suggested the moderate alcohol consumption can reduces probability developing neurodegenerative pathologies. A recent report explored the ability of ethanol to disrupt the generation of complex Aß in vitro and reduce the toxicity in two cell lines. Molecular dynamics simulations were applied to understand how ethanol blocks the aggregation of amyloid. On the other hand, the in silico modeling showed ethanol effect over the dynamics assembling for complex Aß-aggregates mediated by break the hydrosaline bridges between Asp 23 and Lys 28, was are key element for amyloid dimerization. The amyloid pore/channel hypothesis has been explored only in neuronal models, however recently experiments suggested the frog oocytes such an excellent model to explore the mechanism of the amyloid pore/channel hypothesis. So, the used of frog oocytes to explored the mechanism of amyloid aggregates is new, mainly for amyloid/pore hypothesis. Therefore, this experimental model is a powerful tool to explore the mechanism implicates in the Alzheimer's disease pathology and also suggests a model to prevent the Alzheimer's disease pathology.


Subject(s)
Amyloid beta-Peptides/metabolism , Ethanol/chemistry , Models, Molecular , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Amyloid beta-Peptides/chemistry , Animals , Calcium/metabolism , Humans , Oocytes/chemistry , Oocytes/metabolism , Xenopus/growth & development
12.
Syst Biol Reprod Med ; 60(2): 65-71, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24328361

ABSTRACT

Sperm cells are complicated in vitro models. Their viability is limited, and physiology is complex. The study of their properties is of great application in the animal production as viable and functional gametes are essential. It has been shown that the decrease of sperm cell viability parallels an increase of the reactive oxygen species (ROS). Reactive oxygen species is secondary to normal metabolic processes of the cell-like flagellar movement. There is evidence of strategies that reduce ROS levels by using exogenous or endogenous antioxidants with the intention that seminal plasma protects the sperm cells and increases viability. Perhaps viability can increase by reducing that flagellar movement which is regulated by calcium. The phenomenon has not been fully characterized, but it is established that in certain mammalian models, the entrance of calcium via specific channels such as CATsper or voltage-dependent channels, signals flagellar movement. Previous reports have indicated that a change in the concentration of calcium or if the temperature is altered, the function of mammal sperm cells is reduced or blocked and viability prolonged. Fish sperm can remain immobile for several weeks but when activated the number of mobile and viable sperm is reduced at a faster rate. However, if the cells are not mobilized the semen can be preserved for longer periods. As presented in this paper, this supports the notion that by modulating calcium channels to reduce motility the viability of these cells can increase.


Subject(s)
Calcium/metabolism , Sperm Motility , Spermatozoa/metabolism , Animals , Ion Channels/metabolism , Male , Membrane Potentials , Reactive Oxygen Species/metabolism , Sperm Capacitation , Spermatozoa/physiology
13.
Arch Med Res ; 44(1): 1-7, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23291379

ABSTRACT

BACKGROUND: Alzheimer's disease (AD) alters cognitive functions. A mixture of soluble ß-amyloid aggregates (Aß) are known to act as toxic agents. It has been suggested that moderate alcohol intake reduces the development of neurodegenerative diseases, but the molecular mechanisms leading to this type of prevention have been elusive. We show the ethanol effect in the generation of complex Aß in vitro and the impact on the viability of two cell lines. METHODS: The effect of ethanol on the kinetics of ß-amyloid aggregation in vitro was assessed by turbimetry. Soluble- and ethanol-treated ß-amyloid were added to the cell lines HEK and PC-12 to compare their effects on metabolic activity using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. In addition, we used molecular modeling to assess the impact of exposure to ethanol on the structure of ß-amyloid. RESULTS: Exposure to soluble ß-amyloid was toxic to both cell lines; however, exposing the cells to ß-amyloid aggregated in 10 mmol ethanol prevented the effect. In silico modeling suggested that ethanol alters the dynamics for assembling Aß by disrupting a critical salt bridge between residues Asp 23 and Lys 28, required for amyloid dimerization. Thus, ethanol prevented the formation of complex short (∼100 nm) Aß, which are related to higher cell toxicity. CONCLUSIONS: Ethanol prevents the formation of stable Aß dimers in vitro, thus protecting the cells maintained in culture. Accordingly, in silico modelling predicts that soluble ß-amyloid molecules do not form stable multimers when exposed to ethanol.


Subject(s)
Alzheimer Disease/prevention & control , Amyloid beta-Peptides/metabolism , Amyloid beta-Peptides/toxicity , Amyloid/antagonists & inhibitors , Amyloid/toxicity , Ethanol/pharmacology , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Amyloid/metabolism , Amyloid beta-Peptides/antagonists & inhibitors , Amyloid beta-Peptides/chemistry , Animals , HEK293 Cells , Humans , Molecular Dynamics Simulation , Nephelometry and Turbidimetry , PC12 Cells , Rats
14.
Mol Cells ; 34(4): 349-55, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23104436

ABSTRACT

Xenopus laevis oocytes exposed to amyloid-ß aggregate generated oscillatory electric activity (blips) that was recorded by two-microelectrode voltage-clamp. The cells exhibited a series of "spontaneous" blips ranging in amplitude from 3.8 ± 0.9 nA at the beginning of the recordings to 6.8 ± 1.7 nA after 15 min of exposure to 1 µM aggregate. These blips were similar in amplitude to those induced by the channel-forming antimicrobial agents amphotericin B (7.8 ± 1.2 nA) and gramicidin (6.3 ± 1.1 nA). The amyloid aggregate-induced currents were abolished when extracellular Ca(2+) was removed from the bathing solution, suggesting a central role for this cation in generating the spontaneous electric activity. The amyloid aggregate also affected the Ca(2+)-dependent Cl(-) currents of oocytes, as shown by increased amplitude of the transient-outward chloride current (T(out)) and the serum-activated, oscillatory Cl(-) currents. Electron microcopy revealed that amyloid aggregate induced the dissociation of the follicular cells that surround the oocyte, thus leading to a failure in the electro-chemical communication between these cells. This was also evidenced by the suppression of the oscillatory Ca(2+)-dependent ATP-currents, which require proper coupling between oocytes and the follicular cell layer. These observations, made using the X. laevis oocytes as a versatile experimental model, may help to understand the effects of amyloid aggregate on cellular communication.


Subject(s)
Amyloid beta-Peptides/chemistry , Amyloid beta-Peptides/toxicity , Oocytes/drug effects , Oocytes/physiology , Xenopus laevis/metabolism , Animals , Calcium/metabolism , Cell Membrane/drug effects , Cell Membrane/metabolism , Cell Shape/drug effects , Electrophysiological Phenomena/drug effects , Female , Humans , Kinetics , Oocytes/cytology , Oocytes/ultrastructure , Ovarian Follicle/cytology , Ovarian Follicle/drug effects , Ovarian Follicle/physiology , Protein Structure, Quaternary
15.
Neurodegener Dis ; 10(1-4): 23-6, 2012.
Article in English | MEDLINE | ID: mdl-22261402

ABSTRACT

BACKGROUND: We have recently found that Wnt-5a regulates the synaptic structure and function in hippocampal neurons. This ligand is expressed in the hippocampus, stimulates dendritic spine morphogenesis and increases glutamatergic neurotransmission. Moreover, we have also shown that Wnt-5a induces the clustering of PSD-95. OBJECTIVE: To explore the role of Wnt-5a in the formation of synaptic contacts. METHODS: Primary rat hippocampal neurons were exposed to a formylated hexapeptide (Foxy-5) derived from the sequence of Wnt-5a to study synapse formation and function. RESULTS: In short-term experiments, Wnt-5a only induced the clustering of PSD-95 but had no effect on the density of presynaptic puncta, while in long-term experiments, it induced both pre- and postsynaptic protein clustering and the number of synaptic contacts, in agreement with electrophysiological studies. In long-term experiments, Foxy-5 increased miniature excitatory postsynaptic current amplitude and frequency. CONCLUSION: Our findings indicate that Wnt-5a induces synapse formation in hippocampal neurons. In addition, we discuss recent findings indicating a neuroprotective action of Wnt-5a against Aß neurotoxicity.


Subject(s)
Amyloid beta-Peptides/toxicity , Neurons/drug effects , Neurons/physiology , Synapses/drug effects , Wnt Proteins/metabolism , Animals , Cells, Cultured , Disks Large Homolog 4 Protein , Hippocampus/cytology , Intracellular Signaling Peptides and Proteins/metabolism , Membrane Glycoproteins/metabolism , Membrane Potentials/drug effects , Membrane Proteins/metabolism , Nerve Tissue Proteins/metabolism , Oligopeptides/pharmacology , Patch-Clamp Techniques , Rats , Synapses/physiology , Time Factors , Wnt-5a Protein
16.
Neurosci Lett ; 500(1): 20-5, 2011 Aug 01.
Article in English | MEDLINE | ID: mdl-21683123

ABSTRACT

A bicuculline-resistant and TPMPA-sensitive GABAergic component was identified in hippocampal neurons in culture and in acute isolated brain slices. In both preparations, total GABAergic activity showed two inactivation kinetics: fast and slow. RT-PCR, in situ hybridization (ISH) and immunohistochemistry detected expression of GABAρ subunits. Immunogold and electron microscopy indicated that the receptors are mostly extrasynaptic. In addition, by RT-PCR and immunofluorescence we found GABAρ present in amygdala and visual cortex.


Subject(s)
Amygdala/physiology , Hippocampus/physiology , Neurons/physiology , Receptors, GABA-A/physiology , Visual Cortex/physiology , Animals , Embryo, Nonmammalian/cytology , Hippocampus/cytology , Immunohistochemistry , In Situ Hybridization , In Vitro Techniques , Mice , Mice, Inbred C57BL , Miniature Postsynaptic Potentials , Patch-Clamp Techniques , Protein Subunits/physiology , Pyramidal Cells/physiology , Reverse Transcriptase Polymerase Chain Reaction , Synapses/physiology
17.
Proc Natl Acad Sci U S A ; 107(49): 21164-9, 2010 Dec 07.
Article in English | MEDLINE | ID: mdl-21084636

ABSTRACT

Growing evidence indicates that Wingless-type (Wnt) signaling plays an important role in the maturation of the central nervous system. We report here that Wingless-type family member 5A (Wnt-5a) is expressed early in development and stimulates dendrite spine morphogenesis, inducing de novo formation of spines and increasing the size of the preexisting ones in hippocampal neurons. Wnt-5a increased intracellular calcium concentration in dendritic processes and the amplitude of NMDA spontaneous miniature currents. Acute application of Wnt-5a increased the amplitude of field excitatory postsynaptic potentials (fEPSP) in hippocampal slices, an effect that was prevented by calcium-channel blockers. The physiological relevance of our findings is supported by studies showing that Wnt scavengers decreased spine density, miniature excitatory postsynaptic currents, and fEPSP amplitude. We conclude that Wnt-5a stimulates different aspects of synaptic differentiation and plasticity in the mammalian central nervous system.


Subject(s)
Glutamic Acid/physiology , Synapses/ultrastructure , Wnt Proteins/physiology , Animals , Cell Differentiation , Dendrites , Dendritic Spines , Excitatory Postsynaptic Potentials , Hippocampus/cytology , Mice , N-Methylaspartate , Neuronal Plasticity , Neurons/ultrastructure , Synapses/physiology , Wnt-5a Protein
18.
PLoS One ; 5(7): e11820, 2010 Jul 27.
Article in English | MEDLINE | ID: mdl-20676404

ABSTRACT

The mechanisms that induce Alzheimer's disease (AD) are largely unknown thereby deterring the development of disease-modifying therapies. One working hypothesis of AD is that Abeta excess disrupts membranes causing pore formation leading to alterations in ionic homeostasis. However, it is largely unknown if this also occurs in native brain neuronal membranes. Here we show that similar to other pore forming toxins, Abeta induces perforation of neuronal membranes causing an increase in membrane conductance, intracellular calcium and ethidium bromide influx. These data reveal that the target of Abeta is not another membrane protein, but that Abeta itself is the cellular target thereby explaining the failure of current therapies to interfere with the course of AD. We propose that this novel effect of Abeta could be useful for the discovery of anti AD drugs capable of blocking these "Abeta perforates". In addition, we demonstrate that peptides that block Abeta neurotoxicity also slow or prevent the membrane-perforating action of Abeta.


Subject(s)
Alzheimer Disease/metabolism , Amyloid beta-Peptides/pharmacology , Cell Membrane/drug effects , Cell Membrane/metabolism , Neurons/drug effects , Neurons/metabolism , Alzheimer Disease/drug therapy , Amyloid beta-Peptides/metabolism , Animals , Blotting, Western , Calcium/metabolism , Cells, Cultured , Female , Humans , Immunohistochemistry , Mice , Mice, Inbred C57BL , Peptides/pharmacology , Peptides/therapeutic use , Pregnancy , Rats , Rats, Sprague-Dawley
19.
Syst Biol Reprod Med ; 56(4): 303-10, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20718617

ABSTRACT

The morphology and size of spermatozoa make it difficult to study the functional properties of the plasma membrane, however, some studies have revealed the presence of a number of ion channels in this cell. We measured the calcium (Ca(++)) influx induced by depolarization of the plasma membrane and by venom isolated from the Chilean black widow spider (Latrodectus mactans), and functional changes in the presence of either high potassium or total venom. Our results indicate that the venom increased the Ca(++) influx, with an EC50 of 6.1 microg/mL and triggering the acrosome reaction in 43.26% of the cells. The application of potassium (10 mM K(+)) or total venom (10 microg/mL) did not affect the morphology or DNA stability of the sperm. The effects induced by high K(+) and venom suggest that direct blocking of K(+) currents alters the passive properties of the plasma membrane, leading to the entry of Ca(++). These results show the importance of functional changes induced by depolarizing the spermatozoa and by venom. This venom possesses one or more molecules that may be used as pharmacological tools for studies on spermatozoa and have potential applications in reproductive biotechnology.


Subject(s)
Black Widow Spider , Calcium/metabolism , Potassium Channels/drug effects , Spermatozoa/drug effects , Spider Venoms/toxicity , Tetraethylammonium/pharmacology , Acrosome Reaction/drug effects , Animals , Cattle , DNA Fragmentation/drug effects , Dose-Response Relationship, Drug , Male , Membrane Potentials/drug effects , Spermatozoa/metabolism , Spermatozoa/physiology
20.
J Biol Chem ; 285(24): 18939-47, 2010 Jun 11.
Article in English | MEDLINE | ID: mdl-20404321

ABSTRACT

A role for Wnt signal transduction in the development and maintenance of brain structures is widely acknowledged. Recent studies have suggested that Wnt signaling may be essential for synaptic plasticity and neurotransmission. However, the direct effect of a Wnt protein on synaptic transmission had not been demonstrated. Here we show that nanomolar concentrations of purified Wnt3a protein rapidly increase the frequency of miniature excitatory synaptic currents in embryonic rat hippocampal neurons through a mechanism involving a fast influx of calcium from the extracellular space, induction of post-translational modifications on the machinery involved in vesicle exocytosis in the presynaptic terminal leading to spontaneous Ca(2+) transients. Our results identify the Wnt3a protein and a member of its complex receptor at the membrane, the low density lipoprotein receptor-related protein 6 (LRP6) coreceptor, as key molecules in neurotransmission modulation and suggest cross-talk between canonical and Wnt/Ca(2+) signaling in central neurons.


Subject(s)
Calcium/metabolism , Hippocampus/metabolism , Wnt Proteins/metabolism , Animals , Electrophysiology/methods , Exocytosis , Immunohistochemistry , Ligands , Low Density Lipoprotein Receptor-Related Protein-6 , Models, Biological , Neurons/metabolism , Protein Processing, Post-Translational , Rats , Rats, Sprague-Dawley , Receptors, LDL/metabolism , Signal Transduction , Wnt3 Protein
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