RESUMEN
The rotifer-specific biopolymer, namely Rotimer, is a recently discovered group of the biomolecule family. Rotimer has an active role in the biofilm formation initiated by rotifers (e.g., Euchlanis dilatata or Adineta vaga) or in the female-male sexual interaction of monogononts. To understand the Ca2+- and polarity-dependent formation of this multifunctional viscoelastic material, it is essential to explore its molecular composition. The investigation of the rotifer-enhanced biofilm and Rotimer-inductor conglomerate (RIC) formation yielded several protein candidates to predict the Rotimer-specific main components. The exudate of E. dilatata males was primarily applied from different biopolimer-containing samples (biofilm or RIC). The advantage of males over females lies in their degenerated digestive system and simple anatomy. Thus, their exudate is less contaminated with food and endosymbiont elements. The sequenced and annotated genome and transcriptome of this species opened the way for identifying Rotimer proteins by mass spectrometry. The predicted rotifer-biopolymer forming components are SCO-spondins and 14-3-3 protein. The characteristics of Rotimer are similar to Reissner's fiber, which is found in the central nervous system of vertebrates and is mainly formed from SCO-spondins. This molecular information serves as a starting point for its interdisciplinary investigation and application in biotechnology, biomedicine, or neurodegeneration-related drug development.
Asunto(s)
Sistema Nervioso Central , Vertebrados , Animales , Femenino , Masculino , Secuencia de BasesRESUMEN
There are numerous surprising discoveries in current comprehensive biopolymer research, including the description of new types of biopolymers and the extension of their applications. The discovery of a new rotifer-specific biopolymer family (Rotimers) and the exceptional ability of these micrometazoans to inactivate and catabolize human-type neurotoxic aggregates (e.g., beta-amyloids, alpha-synucleins, prions) by their exudates can be mentioned as the original work of our research group. Rotimers are exogenous and protein complex molecules with a calcium-dependent production mechanism in both bdelloid and monogonant rotifers. However, their experimental and application possibilities are still unknown; only part of the class has been explored and described. Current Rotimer-related studies present promising biodiversity and bioactivity of these biomaterials (e.g., antiand disaggregation effects or high degrees of adhesion to other molecules). The primary objective of current research is to explore and develop their application in translational biomedicine. A key area is the design of drug candidates against neurodegeneration-related aggregates based on the molecular information provided by the composition, structure and function of Rotimers. These novel biomaterials have the potential to open new perspectives in the pharmaceutical industry and healthcare.
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Priones , Rotíferos , Animales , Materiales Biocompatibles , Biopolímeros/metabolismo , Biopolímeros/farmacología , Calcio/metabolismo , Humanos , Priones/metabolismo , Priones/farmacología , Rotíferos/metabolismo , Sinucleínas/metabolismoRESUMEN
The rotifer-specific exogenic biopolymer, named Rotimer and its related molecular processes are affected by physical and chemical factors (e.g., temperature, pH or metal ions); however, the study of biological influences (e.g., the presence protozoa) concerning the particle-dependent reproduction (egg laying) and 'biopolymer producing capacity' (BPC) of rotifers is the objective of the present work. Non-planktonic rotifer species (Philodina acuticornis, Adineta vaga, Euchlanis dilatata, and Lecane bulla) were studied in paired micrometazoa-protozoa co-cultures involving Paramecium, Diplonema, and Amoeba. These protozoa can be beneficial food sources, enhancing reproduction, or even toxic factors for the above-mentioned animals, but can also function as particle-like mechanical stimulators. Furthermore, current studies reveal that bdelloids, similarly to monogonants, produce filamentous exudate; moreover, the body of bdelloids is covered by their exudate, unlike that of monogonants, especially in the case of A. vaga. A mathematical formula was developed as an improved version of a previously published viability marker to characterize the BPC and the relative amount of produced exudate in different conditions. Rotifer species secreting biopolymers appear to be a general trait indicating a common evolutionary background (e.g., calcium- and particle dependency) of such molecules; therefore, the BPC becomes an experiential sublethal influencing marker to these micrometazoans.
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Rotíferos , Animales , Evolución Biológica , Biopolímeros , Técnicas de Cocultivo , ReproducciónRESUMEN
Neurodegeneration-related human-type beta-amyloid 1-42 aggregates (H-Aß) are one of the biochemical markers and executive molecules in Alzheimer's disease. The exogenic rotifer-specific biopolymer, namely Rotimer, has a protective effect against H-Aß toxicity on Euchlanis dilatata and Lecane bulla monogonant rotifers. Due to the external particle-dependent secreting activity of these animals, this natural exudate exists in a bound form on the surface of epoxy-metal beads, named as Rotimer Inductor Conglomerate (RIC). In this current work the experiential in vitro molecular interactions between Rotimer and Aßs are presented. The RIC form was uniformly used against H-Aß aggregation processes in stagogram- and fluorescent-based experiments. These well-known cell-toxic aggregates stably and quickly (only taking a few minutes) bind to RIC. The epoxy beads (as carriers) alone or the scrambled version of H-Aß (with random amino acid sequence) were the ineffective and inactive negative controls of this experimental system. The RIC has significant interacting, anti-aggregating and disaggregating effects on H-Aß. To detect these experiments, Bis-ANS and Thioflavin T were applied during amyloid binding, two aggregation-specific functional fluorescent dyes with different molecular characteristics. This newly described empirical interaction of Rotimer with H-Aß is a potential starting point and source of innovation concerning targeted human- and pharmaceutical applications.
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Enfermedad de Alzheimer , Péptidos beta-Amiloides , Enfermedad de Alzheimer/metabolismo , Amiloide/química , Péptidos beta-Amiloides/metabolismo , Animales , Biopolímeros/farmacología , Colorantes Fluorescentes/farmacología , HumanosRESUMEN
The Rotimer, a rotifer-specific biopolymer, is an exogenic bioactive exudate secreted by different monogonant species (e.g. Euchlanis dilatata or Lecane bulla). The production of this viscoelastic biomolecule is induced by different micro-particles, thereby forming a special Rotimer-Inductor Conglomerate (RIC) in a web format. In this case, the water insoluble Carmine crystals, filtered to size (max. diameter was 50 µm), functioned as an inductor. The RIC production is an adequate empirical indicator to follow up this filamentous biopolymer secretion experientially; moreover, this procedure is very sensitive to the environmental factors (temperature, pH, metals and possible natural pollutant agents). The above mentioned species show completely different reactions to these factors, except to the presence of calcium and to the modulating effects of different drugs. One of the novelties of this work is that the Rotimer secretion and consequently, the RIC-formation is a mutually obligatory and evolutionary calcium-dependent process in the concerned monogonants. This in vivo procedure needs calcium, both for the physiology of animals and for fiber formation, particularly in the latter case. The conglomerate covered area (%) and the detection of the longest filament (mm) of the given RIC were the generally and simultaneously applied methods in the current modulating experiments. Exploring the regulatory (e.g. calcium-dependency) and stimulating (e.g. Lucidril effect) possibilities of biopolymer secretion are the basis for optimizing the RIC-production capacities of these micro-metazoans.
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Biopolímeros/biosíntesis , Calcio/farmacología , Ambiente , Contaminantes Ambientales/farmacología , Exudados y Transudados , Rotíferos/metabolismo , Animales , Concentración de Iones de Hidrógeno , Rotíferos/efectos de los fármacos , TemperaturaRESUMEN
AIMS: Non-invasive and simultaneous recording of gastrointestinal (GI) activity during stress induction is still an unexplored field. In our previous investigation, the stress-induced alteration of the gastrointestinal tract was explored in rats. Our aims were to expand our previous rat experiment and to induce stress response in rats (Study 1) and humans (Study 2) to detect the GI tract activity, heart rate and body temperature. MATERIALS AND METHODS: In the preclinical sample, acute stress was induced by immobilization in Sprague-Dawley rats (N = 10). Acute stress response was generated by the Trier Social Stress Test among healthy volunteers (N = 16). Detection of acute stress was measured by using smooth muscle electromyography, which recorded the myoelectric waves of the gastrointestinal tract (stomach, ileum and colon) simultaneously with heart rate and body temperature in rats and humans. KEY FINDINGS: The myoelectric waves of the stomach, the cecum and the ileum increased during immobilization in rats, rising in parallel with heart rate and the dermal temperature of the abdominal surface. The same alterations were found during the stress period among humans, except in the case of the colon, where no change was detected. SIGNIFICANCE: The crucial role of the GI tract in stress response was revealed by translating the outcome of basic research into human results. The similar GI alterations during stress in rats and humans underpin the robustness of our findings. In summary, our preliminary translational-based study can serve as an appropriate basis for further human studies.
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Tracto Gastrointestinal/fisiología , Miocitos del Músculo Liso/metabolismo , Estrés Fisiológico/fisiología , Adulto , Animales , Ciego/fisiología , Colon/fisiología , Electromiografía/métodos , Femenino , Motilidad Gastrointestinal/fisiología , Voluntarios Sanos , Humanos , Íleon/fisiología , Masculino , Músculo Liso/fisiología , Ratas , Ratas Sprague-Dawley , Estómago/fisiologíaRESUMEN
The chemical ecology of rotifers has been little studied. A yet unknown property is presented within some monogonant rotifers, namely the ability to produce an exogenic filamentous biopolymer, named 'Rotimer'. This rotifer-specific viscoelastic fiber was observed in six different freshwater monogonants (Euchlanis dilatata, Lecane bulla, Lepadella patella, Itura aurita, Colurella adriatica and Trichocerca iernis) in exception of four species. Induction of Rotimer secretion can only be achieved by mechanically irritating rotifer ciliate with administering different types (yeast cell skeleton, denatured BSA, epoxy, Carmine or urea crystals and micro-cellulose) and sizes (approx. from 2.5 to 50 µm diameter) of inert particles, as inductors or visualization by adhering particles. The thickness of this Rotimer is 33 ± 3 nm, detected by scanning electron microscope. This material has two structural formations (fiber or gluelike) in nano dimension. The existence of the novel adherent natural product becomes visible by forming a 'Rotimer-Inductor Conglomerate' (RIC) web structure within a few minutes. The RIC-producing capacity of animals, depends on viability, is significantly modified according to physiological- (depletion), drug- (toxin or stimulator) and environmental (temperature, salt content and pH) effects. The E. dilatata-produced RIC is affected by protein disruptors but is resistant to several chemical influences and its Rotimer component has an overwhelming cell (algae, yeast and human neuroblastoma) motility inhibitory effect, associated with low toxicity. This biopolymer-secretion-capacity is protective of rotifers against human-type beta-amyloid aggregates.
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Biopolímeros/metabolismo , Rotíferos/metabolismo , Péptidos beta-Amiloides/farmacología , Animales , Biopolímeros/química , Biopolímeros/farmacología , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Agua Dulce/microbiología , Humanos , Rotíferos/clasificación , Rotíferos/efectos de los fármacos , TemperaturaRESUMEN
Investigation of human neurodegeneration-related aggregates of beta-amyloid 1-42 (Aß42) on bdelloid rotifers is a novel interdisciplinary approach in life sciences. We reapplied an organ size-based in vivo monitoring system, exploring the autocatabolism-related alterations evoked by Aß42, in a glucose-supplemented starvation model. The experientially easy-to-follow size reduction of the bilateral reproductive organ (germovitellaria) in fasted rotifers was rescued by Aß42, serving as a nutrient source- and peptide sequence-specific attenuator of the organ shrinkage phase and enhancer of the regenerative one including egg reproduction. Recovery of the germovitellaria was significant in comparison with the greatly shrunken form. In contrast to the well-known neurotoxic Aß42 (except the bdelloids) with specific regulatory roles, the artificially designed scrambled version (random order of amino acids) was inefficient in autocatabolism attenuation, behaving as negative control. This native Aß42-related modulation of the 'functionally reversible organ shrinkage' can be a potential experiential and supramolecular marker of autocatabolism in vivo.
RESUMEN
Aging and female sex are the major risk factors for Alzheimer's disease and its associated brain amyloid-ß (Aß) neuropathology, but the mechanisms mediating these risk factors remain uncertain. Evidence indicates that Aß aggregation by Zn2+ released from glutamatergic neurons contributes to amyloid neuropathology, so we tested whether aging and sex adversely influences this neurophysiology. Using acute hippocampal slices, we found that extracellular Zn2+-elevation induced by high K+ stimulation was significantly greater with older (65 weeks vs 10 weeks old) rats, and was exaggerated in females. This was driven by slower reuptake of extracellular Zn2+, which could be recapitulated by mitochondrial intoxication. Zn2+:Aß aggregates were toxic to the slices, but Aß alone was not. Accordingly, high K+ caused synthetic human Aß added to the slices to form soluble oligomers as detected by bis-ANS, attaching to neurons and inducing toxicity, with older slices being more vulnerable. Age-dependent energy failure impairing Zn2+ reuptake, and a higher maximal capacity for Zn2+ release by females, could contribute to age and sex being major risk factors for Alzheimer's disease.
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Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Espacio Extracelular/metabolismo , Hipocampo/metabolismo , Agregación Patológica de Proteínas/metabolismo , Zinc/metabolismo , Animales , Femenino , Masculino , Ratas , Ratas Wistar , Factores de RiesgoRESUMEN
The in vivo investigation of kynurenic acid (KYNA) and its analogs is one of the recent exciting topics in pharmacology. In the current study we assessed the biological effects of these molecules on bdelloid rotifers (Philodina acuticornis and Adineta vaga) by monitoring changes in their survival and phenotypical characteristics. In addition to longitudinal (slowly changing) markers (survival, number of rotifers alive and body size index), some dynamic (quickly responding) ones (cellular reduction capacity and mastax contraction frequency) were measured as well. KYNA and its analogs increased longevity, reproduction and growth, whereas reduction capacity and energy-dependent muscular activity decreased conversely. We found that spermidine, a calorie restriction mimetic, exerted similar changes in the applied micro-invertebrates. This characterized systemic profile evoked by the above-mentioned compounds was named beneficial physiologic attenuation. In reference experiments, using a stimulator (cyclic adenosine monophosphate) and a toxin (sodium azide), all parameters changed in the same direction (positively or negatively, respectively), as expected. The currently described adaptive phenomenon in bdelloid rotifers may provide holistic perspectives in translational research.
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Ácido Quinurénico/análogos & derivados , Ácido Quinurénico/farmacología , Rotíferos/fisiología , Animales , Cinética , Ácido Quinurénico/química , Rotíferos/efectos de los fármacos , Análisis de SupervivenciaRESUMEN
In many biology- and chemistry-related research fields and experiments the quantification of the peptide and/or protein concentration in samples are essential. Every research environment has unique requirements, e.g. metal ions, incubation times, photostability, pH, protease inhibitors, chelators, detergents, etc. A new protein assay may be adequate in different experiments beyond or instead of the well-known standard protocols (e.g. Qubit, Bradford or bicinchoninic acid) in related conceptions. Based on our previous studies, we developed a novel protein assay applying the 4,4'-Dianilino-1,1'-binaphthyl-5,5'-disulfonic acid dipotassium salt (BisANS) fluorescent dye. This molecule has several advantageous properties related to protein detection: good solubility in water, high photostability at adequate pH, quick interaction kinetics (within seconds) with proteins and no exclusionary sensitivity to the chelator, detergent and inhibitor ingredients. The protocol described in this work is highly sensitive in a large spectrum to detect protein (100-fold diluted samples) concentrations (from 0.28 up to more than 100 µg/mL). The BisANS protein assay is valid and applicable for quantification of the amount of protein in different biological and/or chemical samples.
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Naftalenosulfonatos de Anilina/química , Bioensayo/normas , Colorantes Fluorescentes/química , Proteínas de Saccharomyces cerevisiae/análisis , Albúmina Sérica Bovina/análisis , Animales , Bovinos , Detergentes/química , Concentración de Iones de Hidrógeno , Límite de Detección , Saccharomyces cerevisiae/química , Solubilidad , Agua/químicaRESUMEN
Twelve compounds (1â»12) were isolated from the methanol extract of brick cap mushroom (Hypholoma lateritium (Schaeff.) P. Kumm.). The structures of the compounds were elucidated using extensive spectroscopic analyses, including NMR and MS measurements. Lanosta-7,9(11)-diene-12ß,21α-epoxy-2α,3ß,24ß,25-tetraol (1) and 8-hydroxy-13-oxo-9E,11E-octa-decadienoic acid (2) were identified as new natural products, together with ten known compounds, from which 3ß-hydroxyergosta-7,22-diene (4), demethylincisterol A2 (5), cerevisterol (6), 3ß-O-glucopyranosyl-5,8-epidioxyergosta-6,22-diene (7), fasciculol E (9), and uridine (12) were identified in this species for the first time. The isolated triterpenes (1, 3â»11) were investigated for their toxicity in vivo using bdelloid rotifer assays. Most of the examined steroids in general showed low toxicity, although the effects of the compounds varied in a wider range from the non-toxic lanosta-7,9(11)-diene-12ß,21α-epoxy-2α,3ß,24ß,25-tetraol (1) to the significantly toxic cerevisterol (6), with substantial dependence in some cases on the presence of nutrient in the experimental environment.
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Agaricales/química , Triterpenos/química , Triterpenos/aislamiento & purificación , Animales , Fraccionamiento Químico , Espectroscopía de Resonancia Magnética , Conformación Molecular , Estructura Molecular , Rotíferos/efectos de los fármacos , Pruebas de Toxicidad , Triterpenos/toxicidadRESUMEN
Rotifers are microinvertebrate models to study the phylogenetically based mechanisms of aging. Our study aimed to develop a physiological system with electron deprivation via a chemical electron carrier/acceptor pair together with extreme caloric restriction (ECR). Middle-aged Philodina acuticornis rotifers were treated with combinations of phenazine methosulfate (PMS, electron carrier) and 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt (XTT, electron acceptor) for a period of 72 hours under total food deprivation (preselection). The ability of XTT to be reduced was confirmed both in vitro (with NADH) and in vivo (with live rotifers). Subsequently, the respective electron acceptor alone at a lower dose was administered in combination with ECR for several months on preselected survivors. We found that the longevity of rotifers markedly increased (4×) after PMS/XTT/total food deprivation preselection followed by XTT/ECR treatment. Ascorbic acid in equivalent concentrations caused similar but less pronounced tendencies. The synergistic effect of chemical electron deprivation and ECR caused delayed aging and the development of an outstanding phenotype that we refer to as "super rotifers," characterized by increased longevity and retained reproductive ability compared with normal middle-aged individuals. The presented model provides new insights into the connection between redox modulation and age-related features in vivo.
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Restricción Calórica , Longevidad/fisiología , Oxidación-Reducción , Rotíferos/fisiología , Animales , Privación de Alimentos , Indicadores y Reactivos , Metosulfato de Metilfenazonio , Modelos Animales , Sales de TetrazolioRESUMEN
Rotifers have been widely used as well-characterized models of aging, since their multiorgan character makes them suitable as in vivo toxicological and lifespan models. Here we report the assessment of four adaptogenic plants and their extracts for the first time in this model. The effects on rotifer viability of extracts and characteristic active markers of Panax ginseng, Withania somnifera, Leuzea carthamoides, and Rhodiola rosea were tested in vivo. The crude extracts were nontoxic to Philodina acuticornis bdelloid rotifers; however, the pure substances of the plants influenced negatively the viability. Ginsenoside Rb1 and secondary metabolites of Withania somnifera exerted deleterious effect on the animals. The aglycone tyrosol and cinnamyl alcohol (from Rhodiola rosea) were more toxic than their glycosides salidroside and rosavin. Although the 20-OH-ecdysone and ajugasterone C (from Leuzea carthamoides) are chemically very similar, the latter was less toxic.
RESUMEN
Alzheimer's disease is one of the most common chronic neurodegenerative disorders. Despite several in vivo and clinical studies, the cause of the disease is poorly understood. Currently, amyloid ß (Aß) peptide and its tendency to assemble into soluble oligomers are known as a main pathogenic event leading to the interruption of synapses and brain degeneration. Targeting neurotoxic Aß oligomers can help recognize the disease at an early stage or it can be a potential therapeutic approach. Unnatural ß-peptidic foldamers are successfully used against many different protein targets due to their favorable structural and pharmacokinetic properties compared to small molecule or protein-like drug candidates. We have previously reported a tetravalent foldamer-dendrimer conjugate which can selectively bind Aß oligomers. Taking advantage of multivalency and foldamers, we synthesized different multivalent foldamer-based conjugates to optimize the geometry of the ligand. Isothermal titration calorimetry (ITC) was used to measure binding affinity to Aß, thereafter 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) based tissue viability assay and impedance-based viability assay on SH-SY5Y cells were applied to monitor Aß toxicity and protective effects of the compounds. Important factors for high binding affinity were determined and a good correlation was found between influencing the valence and the capability of the conjugates for Aß binding.
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Enfermedad de Alzheimer/tratamiento farmacológico , Péptidos beta-Amiloides/química , Dendrímeros/química , Fragmentos de Péptidos/química , Enfermedad de Alzheimer/genética , Péptidos beta-Amiloides/antagonistas & inhibidores , Precursor de Proteína beta-Amiloide/antagonistas & inhibidores , Precursor de Proteína beta-Amiloide/química , Animales , Calorimetría , Dendrímeros/uso terapéutico , Humanos , Ligandos , Neuronas/química , Neuronas/efectos de los fármacos , Fragmentos de Péptidos/uso terapéutico , Unión Proteica , Conformación Proteica/efectos de los fármacos , Pliegue de Proteína/efectos de los fármacosRESUMEN
Neurodegenerative diseases are linked to a systemic enzyme resistance of toxic aggregated molecules and their pathological consequences. This paper presents a unique phenomenon that Philodina acuticornis, a bdelloid rotifer, is able to catabolize different types of neurotoxic peptide and protein aggregates (such as beta-amyloids /Aß/, alpha-synuclein, and prion) without suffering any damage. P. acuticornis is capable of using these aggregates as an exclusive energy source (i.e., as 'food', identified in the digestive system and body) in a hermetically isolated microdrop environment, increasing their survival. As regards Aß1-42, five other bdelloid rotifer species were also found to be able to perform this phenomenon. Based on our experiments, the Aß1-42-treated bdelloid rotifers demonstrate significantly increased survival (e.g. mean lifespan = 51 ± 2.71 days) compared to their untreated controls (e.g. mean lifespan = 14 ± 2.29 days), with similar improvements in a variety of phenotypic characteristics. To our knowledge, no other animal species have so far been reported to have a similar capability. For all other microscopic species tested, including monogonant rotifers and non-rotifers, the treatment with Aß1-42 aggregates proved to be either toxic or simply ineffective. This paper describes and proves the existence of an unprecedented in vivo catabolic capability of neurotoxic aggregates by bdelloid rotifers, with special focus on P. acuticornis. Our results may provide the basis for a new preclinical perspective on therapeutic research in human neurodegenerative diseases.
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Péptidos beta-Amiloides/metabolismo , Rotíferos/metabolismo , Péptidos beta-Amiloides/toxicidad , Animales , Caenorhabditis elegans/metabolismo , Línea Celular Tumoral , Humanos , Estimación de Kaplan-Meier , Lobosea/metabolismo , Metabolismo , Enfermedades Neurodegenerativas/metabolismo , Oligohimenóforos/metabolismo , Platelmintos/metabolismo , Agregación Patológica de Proteínas/metabolismo , Especificidad de la Especie , Tardigrada/metabolismoRESUMEN
The group of diterpene alkaloids contains numerous compounds with complex chemistry and diverse pharmacological activities. Beside toxicity, these compounds possess activity on the cardiovascular system, tumor cell lines and nervous system. The pharmacological properties have been described using in vitro and in vivo techniques; however, the bioactivities of many compounds have not thoroughly been studied. Here we report on the in vivo evaluation of ten diterpene alkaloids using bdelloid rotifer assays. Napelline exerted toxic effects on rotifers, while wide tolerance range was observed for other investigated compounds. Weak toxicity of songorine is supported by our experiment. Toxicological data for senbusine A, senbusine C, septentrioidine and hetisinone are reported for the first time.
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Alcaloides/toxicidad , Diterpenos/toxicidad , Rotíferos/metabolismo , Animales , Evaluación Preclínica de Medicamentos/métodosRESUMEN
Brain Aß1-42 accumulation is considered an upstream event in pathogenesis of Alzheimer's disease. However, accumulating evidence indicates that other neurochemical changes potentiate the toxicity of this constitutively generated peptide. Here we report that the interaction of Aß1-42 with extracellular Zn2+ is essential for in vivo rapid uptake of Aß1-42 and Zn2+ into dentate granule cells in the normal rat hippocampus. The uptake of both Aß1-42 and Zn2+ was blocked by CaEDTA, an extracellular Zn2+ chelator, and by Cd2+, a metal that displaces Zn2+ for Aß1-42 binding. In vivo perforant pathway LTP was unaffected by perfusion with 1000 nm Aß1-42 in ACSF without Zn2+ However, LTP was attenuated under preperfusion with 5 nm Aß1-42 in ACSF containing 10 nm Zn2+, recapitulating the concentration of extracellular Zn2+, but not with 5 nm Aß1-40 in ACSF containing 10 nm Zn2+ Aß1-40 and Zn2+ were not taken up into dentate granule cells under these conditions, consistent with lower affinity of Aß1-40 for Zn2+ than Aß1-42 Aß1-42-induced attenuation of LTP was rescued by both CaEDTA and CdCl2, and was observed even with 500 pm Aß1-42 Aß1-42 injected into the dentate granule cell layer of rats induced a rapid memory disturbance that was also rescued by coinjection of CdCl2 The present study supports blocking the formation of Zn-Aß1-42 in the extracellular compartment as an effective preventive strategy for Alzheimer's disease.SIGNIFICANCE STATEMENT Short-term memory loss occurs in normal elderly and increases in the predementia stage of Alzheimer's disease (AD). Amyloid-ß1-42 (Aß1-42), a possible causing peptide in AD, is bound to Zn2+ in the extracellular compartment in the hippocampus induced short-term memory loss in the normal rat brain, suggesting that extracellular Zn2+ is essential for Aß1-42-induced short-term memory loss. The evidence is important to find an effective preventive strategy for AD, which is blocking the formation of Zn-Aß1-42 in the extracellular compartment.
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Péptidos beta-Amiloides/metabolismo , Disfunción Cognitiva/metabolismo , Hipocampo/metabolismo , Potenciación a Largo Plazo , Trastornos de la Memoria/metabolismo , Fragmentos de Péptidos/metabolismo , Zinc/metabolismo , Animales , Disfunción Cognitiva/complicaciones , Progresión de la Enfermedad , Líquido Extracelular/metabolismo , Masculino , Trastornos de la Memoria/complicaciones , Unión Proteica , Ratas , Ratas WistarRESUMEN
Rotifers have been used in biological research as well-characterized models of aging. Their multi-organ characters and their sensitivity for chemicals and environmental changes make them useful as in vivo toxicological and lifespan models. Our aim was to create a bdelloid rotifer model to use in high-throughput viability and non-invasive assays. In order to identify our species Philodina acuticornis odiosa (PA), 18S rDNA-based phylogenetic analysis was carried out and their species-specific morphological markers identified. To execute the rotifer-based experiments, we developed an oil-covered water-drop methodology adapted from human in vitro fertilization techniques. This enables toxicological observations of individual one-housed rotifers in a closed and controllable micro-environment for up to several weeks. Hydrogen peroxide (H2O2) and sodium azide (NaN3) exposures were used as well-understood toxins. The toxicity and survival lifespan (TSL), the bright light disturbance (BLD) the mastax contraction frequency (MCF) and the cellular reduction capacity (CRC), indices were recorded. These newly developed assays were used to test the effects of lethal and sublethal doses of the toxins. The results showed the expected dose-dependent decrease in indices. These four different assays can either be used independently or as an integrated system for studying rotifers. These new indices render the PA invertebrate rotifer model a quantitative system for measuring viability, toxicity and lifespan (with TSL), systemic reaction capacity (with BLD), organic functionality (with MCF) and reductive capability of rotifers (with CRC), in vivo. This novel multi-level system is a reliable, sensitive and replicable screening tool with potential application in pharmaceutical science.
Asunto(s)
Monitoreo del Ambiente/métodos , Peróxido de Hidrógeno/toxicidad , Rotíferos/efectos de los fármacos , Azida Sódica/toxicidad , Animales , Bioensayo , Ensayos Analíticos de Alto Rendimiento , Humanos , Filogenia , ARN Ribosómico 18S/genética , Rotíferos/genética , Sensibilidad y Especificidad , Especificidad de la Especie , Análisis de SupervivenciaRESUMEN
Background: Adiponectin and leptin are implicated in the initiation and pathomechanism of Alzheimer's disease (AD). The serum concentrations of these adipokines has been extensively studied in AD, however little is known about their receptors in this disease. Objective: We developed a novel approach to examine whether the receptors of adiponectin (AdipoR1 and -R2) and/or leptin (LepR) can contribute to AD pathomechanism. To achieve this, we investigated the effect of both genetic and environmental factors associated with AD on the expression of these receptors. Method: We used C57BL/6J (WT) and APP(swe)/Presen(e9d)1 (AD) mice. Both strains were exposed to restraint stress (RS) daily for 6h over different time periods. Then, we measured the mRNA expression of AdipoR1, AdipoR2 and LepR and the level of AdipoR1 and AdipoR2 proteins in the hippocampal and prefrontal cortical areas of each mouse. Results: We detected brain region specific transcriptomic changes of adiponectin receptors induced by APP and PS1 transgenes. Both acute and chronic RS caused significant elevations in AdipoR1 mRNA expression in the hippocampus of WT mice. In the prefrontal cortex, the mRNA expression of AdipoR1 followed a biphasic course. In AD mice, RS did not promote any changes in the expression of AdipoR1 mRNA and AdipoR1 protein levels. AdipoR2 mRNA in AD animals, however, showed a significant increase in the prefrontal cortex during RS. Regarding AdipoR1 and AdipoR2 mRNA and protein expression, relevant changes could be measured during stress exposure in both brain areas. Furthermore, stress exposed groups exhibited little change in LepR mRNA expression. Conclusion: Our findings indicate that carrying the transgenes associated with AD induces modification in the expression of both adiponectin receptors. In the case of a normal genetic background, these receptors also appear to be sensitive to environmental factors, while in a genetically determined AD model less response to stress stimuli could be observed. The results suggest that modification of adipokine receptors could also be considered in the therapeutic approach to AD.