RESUMEN
The α9α10 nicotinic cholinergic receptor (nAChR) is a ligand-gated pentameric cation-permeable ion channel that mediates synaptic transmission between descending efferent neurons and mechanosensory inner ear hair cells. When expressed in heterologous systems, α9 and α10 subunits can assemble into functional homomeric α9 and heteromeric α9α10 receptors. One of the differential properties between these nAChRs is the modulation of their ACh-evoked responses by extracellular calcium (Ca2+). While α9 nAChRs responses are blocked by Ca2+, ACh-evoked currents through α9α10 nAChRs are potentiated by Ca2+ in the micromolar range and blocked at millimolar concentrations. Using chimeric and mutant subunits, together with electrophysiological recordings under two-electrode voltage-clamp, we show that the TM2-TM3 loop of the rat α10 subunit contains key structural determinants responsible for the potentiation of the α9α10 nAChR by extracellular Ca2+. Moreover, molecular dynamics simulations reveal that the TM2-TM3 loop of α10 does not contribute to the Ca2+ potentiation phenotype through the formation of novel Ca2+ binding sites not present in the α9 receptor. These results suggest that the TM2-TM3 loop of α10 might act as a control element that facilitates the intramolecular rearrangements that follow ACh-evoked α9α10 nAChRs gating in response to local and transient changes of extracellular Ca2+ concentration. This finding might pave the way for the future rational design of drugs that target α9α10 nAChRs as otoprotectants.
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Calcio , Receptores Nicotínicos , Animales , Ratas , Acetilcolina/metabolismo , Acetilcolina/farmacología , Secuencia de Aminoácidos , Sitios de Unión , Calcio/metabolismo , Simulación de Dinámica Molecular , Técnicas de Placa-Clamp , Subunidades de Proteína/metabolismo , Subunidades de Proteína/genética , Receptores Nicotínicos/metabolismo , Receptores Nicotínicos/genética , Receptores Nicotínicos/química , Xenopus laevisRESUMEN
Coralsnakes (Micrurus spp.) are the only elapids found throughout the Americas. They are recognized for their highly neurotoxic venom, which is comprised of a wide variety of toxins, including the stable, low-mass toxins known as three-finger toxins (3FTx). Due to difficulties in venom extraction and availability, research on coralsnake venoms is still very limited when compared to that of other Elapidae snakes like cobras, kraits, and mambas. In this study, two previously described 3FTx from the venom of M. corallinus, NXH1 (3SOC1_MICCO), and NXH8 (3NO48_MICCO) were characterized. Using in silico, in vitro, and ex vivo experiments, the biological activities of these toxins were predicted and evaluated. The results showed that only NXH8 was capable of binding to skeletal muscle cells and modulating the activity of nAChRs in nerve-diaphragm preparations. These effects were antagonized by anti-rNXH8 or antielapidic sera. Sequence analysis revealed that the NXH1 toxin possesses eight cysteine residues and four disulfide bonds, while the NXH8 toxin has a primary structure similar to that of non-conventional 3FTx, with an additional disulfide bond on the first loop. These findings add more information related to the structural diversity present within the 3FTx class, while expanding our understanding of the mechanisms of the toxicity of this coralsnake venom and opening new perspectives for developing more effective therapeutic interventions.
Asunto(s)
Clonación Molecular , Serpientes de Coral , Venenos Elapídicos , Músculo Esquelético , Receptores Nicotínicos , Animales , Venenos Elapídicos/química , Venenos Elapídicos/toxicidad , Venenos Elapídicos/genética , Receptores Nicotínicos/metabolismo , Receptores Nicotínicos/genética , Músculo Esquelético/metabolismo , Músculo Esquelético/efectos de los fármacos , Secuencia de Aminoácidos , MasculinoRESUMEN
The cholinergic system plays an essential role in brain development, physiology, and pathophysiology. Herein, we review how specific alterations in this system, through genetic mutations or abnormal receptor function, can lead to aberrant neural circuitry that triggers disease. The review focuses on the nicotinic acetylcholine receptor (nAChR) and its role in addiction and in neurodegenerative and neuropsychiatric diseases and epilepsy. Cholinergic dysfunction is associated with inflammatory processes mainly through the involvement of α7 nAChRs expressed in brain and in peripheral immune cells. Evidence suggests that these neuroinflammatory processes trigger and aggravate pathological states. We discuss the preclinical evidence demonstrating the therapeutic potential of nAChR ligands in Alzheimer disease, Parkinson disease, schizophrenia spectrum disorders, and in autosomal dominant sleep-related hypermotor epilepsy. PubMed and Google Scholar bibliographic databases were searched with the keywords indicated below.
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Enfermedad de Alzheimer , Artrogriposis , Receptores Nicotínicos , Humanos , Membrana Celular , Encéfalo , Receptores Nicotínicos/genéticaRESUMEN
Tobacco smoking is the leading risk factor for many respiratory diseases. Several genes are associated with nicotine addiction, such as CHRNA5 and ADAM33. This research aims to evaluate the association of the polymorphisms rs16969968 (CHRNA5) and rs3918396 (ADAM33) in patients who developed severe COVID-19. We included 917 COVID-19 patients hospitalized with critical disease and oxygenation impairment. They were divided into two groups, tobacco-smoking (n = 257) and non-smoker (n = 660) patients. The genotype and allele frequencies of two single nucleotide variants, the rs16969968 (CHRNA5) and rs3918396 (ADAM33), were evaluated. The rs3918396 in ADAM33 does not show a significative association. We analyzed the study population according to the rs16969968 genotype (GA + AA, n = 180, and GG, n = 737). The erythrocyte sedimentation rate (ESR) shows statistical differences; the GA + AA group had higher values than the GG group (p = 0.038, 32 vs. 26 mm/h, respectively). The smoking patients and GA or AA genotype carriers had a high positive correlation (p < 0.001, rho = 0.753) between fibrinogen and C-reactive protein. COVID-19 patients and smokers carriers of one or two copies of the risk allele (rs16969968/A) have high ESR and a positive correlation between fibrinogen and C-reactive protein.
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COVID-19 , Receptores Nicotínicos , Humanos , Proteína C-Reactiva/genética , Receptores Nicotínicos/genética , Polimorfismo de Nucleótido Simple , COVID-19/genética , Fumar Tabaco , Biomarcadores , Fibrinógeno/genética , Nucleótidos , Predisposición Genética a la Enfermedad , Proteínas ADAM/genéticaRESUMEN
Nicotinic acetylcholine receptors (nAChRs) comprise a family of pentameric ligand-gated ion channels widely distributed in the central and peripheric nervous system and in non-neuronal cells. nAChRs are involved in chemical synapses and are key actors in vital physiological processes throughout the animal kingdom. They mediate skeletal muscle contraction, autonomic responses, contribute to cognitive processes, and regulate behaviors. Dysregulation of nAChRs is associated with neurological, neurodegenerative, inflammatory and motor disorders. In spite of the great advances in the elucidation of nAChR structure and function, our knowledge about the impact of post-translational modifications (PTMs) on nAChR functional activity and cholinergic signaling has lagged behind. PTMs occur at different steps of protein life cycle, modulating in time and space protein folding, localization, function, and protein-protein interactions, and allow fine-tuned responses to changes in the environment. A large body of evidence demonstrates that PTMs regulate all levels of nAChR life cycle, with key roles in receptor expression, membrane stability and function. However, our knowledge is still limited, restricted to a few PTMs, and many important aspects remain largely unknown. There is thus a long way to go to decipher the association of aberrant PTMs with disorders of cholinergic signaling and to target PTM regulation for novel therapeutic interventions. In this review we provide a comprehensive overview of what is known about how different PTMs regulate nAChR.
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Receptores Nicotínicos , Animales , Receptores Nicotínicos/genética , Transducción de Señal/fisiología , Transmisión Sináptica , Colinérgicos , Procesamiento Proteico-PostraduccionalRESUMEN
Thiamethoxam (TMX) is a systemic neonicotinoid that acts as a partial agonist of the nicotinic acetylcholine receptors (nAChRs). However, target species have shown resistance to formulations based on such neonicotinoids, which can also be expected for non-target insects. This research aimed to study the effects of a formulation based on TMX [Cruiser® 350 FS (CRZ)] on the life traits of Chironomus xanthus filial generation (F1) and compare it with the parental generation (P). Environmentally relevant concentrations of CRZ significantly decreased larvae growth P generation , also slowing and decreasing their emergence. Larvae of the F1 generation were less sensitive than their parents, suggesting that the progeny were able to thrive and perform basic physiological functions better than the parental generation. Our results highlight that insect resistance to neonicotinoids may be associated with the better performance of the filial generation, which is related to the change in affinities of the active ingredient for the sub-units constituting the nAChRs subtypes of F1 organisms, inherited from P organisms that were able to survive and reproduce. Moreover, further studies using biochemical and omics tools should be performed to disentangle the specific changes occurring at the nAChRs throughout insect development.
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Chironomidae , Insecticidas , Receptores Nicotínicos , Animales , Insecticidas/farmacología , Larva , Chironomidae/genética , Tiametoxam/farmacología , Neonicotinoides/toxicidad , Insectos , Receptores Nicotínicos/genética , Nitrocompuestos/toxicidadRESUMEN
Lithium chloride has been widely used as a therapeutic mood stabilizer. Although cumulative evidence suggests that lithium plays modulatory effects on postsynaptic receptors, the underlying mechanism by which lithium regulates synaptic transmission has not been fully elucidated. In this work, by using the advantageous neuromuscular synapse, we evaluated the effect of lithium on the stability of postsynaptic nicotinic acetylcholine receptors (nAChRs) in vivo. We found that in normally innervated neuromuscular synapses, lithium chloride significantly decreased the turnover of nAChRs by reducing their internalization. A similar response was observed in CHO-K1/A5 cells expressing the adult muscle-type nAChRs. Strikingly, in denervated neuromuscular synapses, lithium led to enhanced nAChR turnover and density by increasing the incorporation of new nAChRs. Lithium also potentiated the formation of unstable nAChR clusters in non-synaptic regions of denervated muscle fibres. We found that denervation-dependent re-expression of the foetal nAChR γ-subunit was not altered by lithium. However, while denervation inhibits the distribution of ß-catenin within endplates, lithium-treated fibres retain ß-catenin staining in specific foci of the synaptic region. Collectively, our data reveal that lithium treatment differentially affects the stability of postsynaptic receptors in normal and denervated neuromuscular synapses in vivo, thus providing novel insights into the regulatory effects of lithium on synaptic organization and extending its potential therapeutic use in conditions affecting the peripheral nervous system.
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Cloruro de Litio/farmacología , Unión Neuromuscular/efectos de los fármacos , Sinapsis/efectos de los fármacos , Potenciales Sinápticos/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos , Transmisión Sináptica/fisiología , Animales , Células CHO , Cricetinae , Cricetulus , Desnervación/métodos , Ratones , Microscopía Fluorescente/métodos , Unión Neuromuscular/fisiología , Unión Neuromuscular/cirugía , Transporte de Proteínas/efectos de los fármacos , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo , Sinapsis/metabolismo , Sinapsis/fisiología , Potenciales Sinápticos/fisiologíaRESUMEN
In zebrafish, nicotine is known to regulate sensitivity to psychostimulants via epigenetic mechanisms. Little however is known about the regulation of addictive-like behavior by DNA methylation processes. To evaluate the influence of DNA methylation on nicotine-induced conditioned place preference (CPP), zebrafish were exposed to methyl supplementation through oral L-methionine (Met) administration. Met was found to reduce dramatically nicotine-induced CPP as well as behaviors associated with drug reward. The reduction was associated with the upregulation of DNA methyltransferases (DNMT1 and 3) as well as with the downregulation of methyl-cytosine dioxygenase-1 (TET1) and of nicotinic receptor subunits. Met also increased the expression of histone methyltransferases in nicotine-induced CPP groups. It reversed the nicotine-induced reduction in the methylation at α7 and NMDAR1 gene promoters. Treatment with the DNMT inhibitor 5-aza-2'-deoxycytidine (AZA) was found to reverse the effects of Met in structures of the reward pathway. Interestingly, Met did not modify the amount of the phospho-form of CREB (pCREB), a key factor establishing nicotine conditioning, whereas AZA increased pCREB levels. Our data suggest that nicotine-seeking behavior is partially dependent on DNA methylation occurring probably at specific gene loci, such as α7 and NMDAR1 receptor gene promoters. Overall, they suggest that Met should be considered as a potential therapeutic drug to treat nicotine addiction.
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Conducta Animal/fisiología , Conducta de Elección , Suplementos Dietéticos , Metionina/farmacología , Nicotina/farmacología , Pez Cebra/fisiología , 5-Metilcitosina/metabolismo , Animales , Azacitidina/farmacología , Conducta Animal/efectos de los fármacos , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Condicionamiento Clásico , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Metilación de ADN/efectos de los fármacos , Metilación de ADN/genética , Epigénesis Genética/efectos de los fármacos , Fosforilación/efectos de los fármacos , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores de N-Metil-D-Aspartato/genética , Receptores de N-Metil-D-Aspartato/metabolismo , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo , Recompensa , Pez Cebra/genética , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismoRESUMEN
Studies about the relationship between substances consumed by humans and their impact on health, in animal models, have been a challenge due to differences between species in the animal kingdom. However, the homology of certain genes has allowed extrapolation of certain knowledge obtained in animals. Drosophila melanogaster, studied for decades, has been widely used as model for human diseases as well as to study responses associated with the consumption of several substances. In the present work we explore the impact of tobacco consumption on a model of 'smoking flies'. Throughout these experiments, we aim to provide information about the effects of tobacco consumption on cardiac physiology. We assessed intracellular calcium handling, a phenomenon underlying cardiac contraction and relaxation. Flies chronically exposed to tobacco smoke exhibited an increased heart rate and alterations in the dynamics of the transient increase of intracellular calcium in myocardial cells. These effects were also evident under acute exposure to nicotine of the heart, in a semi-intact preparation. Moreover, the alpha 1 and 7 subunits of the nicotinic receptors are involved in the heart response to tobacco and nicotine under chronic (in the intact fly) as well as acute exposure (in the semi-intact preparation). The present data elucidate the implication of the intracellular cardiac pathways affected by nicotine on the heart tissue. Based on the probed genetic and physiological similarity between the fly and human heart, cardiac effects exerted by tobacco smoke in Drosophila advances our understanding of the impact of it in the human heart. Additionally, it may also provide information on how nicotine-like substances, e.g. neonicotinoids used as insecticides, affect cardiac function.This article has an associated First Person interview with the first author of the paper.
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Drosophila melanogaster/efectos de los fármacos , Corazón/efectos de los fármacos , Productos de Tabaco/efectos adversos , Fumar Tabaco/efectos adversos , Animales , Biomarcadores , Fenómenos Fisiológicos Cardiovasculares/efectos de los fármacos , Pruebas de Función Cardíaca , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismoRESUMEN
INTRODUCTION: Tobacco smoking is the leading cause of preventable death globally. Smoking quantity, measured in cigarettes per day, is influenced both by the age of onset of regular smoking (AOS) and by genetic factors, including a strong effect of the nonsynonymous single-nucleotide polymorphism rs16969968. A previous study by Hartz et al. reported an interaction between these two factors, whereby rs16969968 risk allele carriers who started smoking earlier showed increased risk for heavy smoking compared with those who started later. This finding has yet to be replicated in a large, independent sample. METHODS: We performed a preregistered, direct replication attempt of the rs16969968 × AOS interaction on smoking quantity in 128 383 unrelated individuals from the UK Biobank, meta-analyzed across ancestry groups. We fit statistical association models mirroring the original publication as well as formal interaction tests on multiple phenotypic and analytical scales. RESULTS: We replicated the main effects of rs16969968 and AOS on cigarettes per day but failed to replicate the interaction using previous methods. Nominal significance of the rs16969968 × AOS interaction term depended strongly on the scale of analysis and the particular phenotype, as did associations stratified by early/late AOS. No interaction tests passed genome-wide correction (α = 5e-8), and all estimated interaction effect sizes were much smaller in magnitude than previous estimates. CONCLUSIONS: We failed to replicate the strong rs16969968 × AOS interaction effect previously reported. If such gene-moderator interactions influence complex traits, they likely depend on scale of measurement, and current biobanks lack the power to detect significant genome-wide associations given the minute effect sizes expected. IMPLICATIONS: We failed to replicate the strong rs16969968 × AOS interaction effect on smoking quantity previously reported. If such gene-moderator interactions influence complex traits, current biobanks lack the power to detect significant genome-wide associations given the minute effect sizes expected. Furthermore, many potential interaction effects are likely to depend on the scale of measurement employed.
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Fumar , Edad de Inicio , Predisposición Genética a la Enfermedad , Humanos , Proteínas del Tejido Nervioso/genética , Polimorfismo de Nucleótido Simple , Receptores Nicotínicos/genética , Fumar/genética , Fumar TabacoRESUMEN
Neuronal α7 and α4ß2 are the predominant nicotinic acetylcholine receptor (nAChR) subtypes found in the brain, particularly in the hippocampus. The effects of lovastatin, an inhibitor of cholesterol biosynthesis, on these two nAChRs endogenously expressed in rat hippocampal neuronal cells were evaluated in the 0.01-1 µM range. Chronic (14 days) lovastatin treatment augmented cell-surface levels of α7 and α4 nAChRs, as measured by fluorescence microscopy and radioactive ligand binding assays. This was accompanied in both cases by an increase in total protein receptor levels as determined by Western blots. At low lovastatin concentrations (10-100 nM), the increase in α4 nAChR in neurites was higher than in neuronal cell somata; the opposite occurred at higher (0.5-1 µM) lovastatin concentrations. In contrast, neurite α7 nAChRs raised more than somatic α7 nAChRs at all lovastatin concentrations tested. These results indicate that cholesterol levels homeostatically regulate α7 and α4 nAChR levels in a differential manner through mechanisms that depend on statin concentration and receptor localization. The neuroprotective pleomorphic effects of statins may act by reestablishing the homeostatic equilibrium.
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Lovastatina/farmacología , Neuronas/efectos de los fármacos , Receptores Nicotínicos/genética , Receptor Nicotínico de Acetilcolina alfa 7/genética , Animales , Colesterol/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Hipocampo/efectos de los fármacos , Humanos , Neuronas/metabolismo , Fármacos Neuroprotectores/farmacología , RatasRESUMEN
Zebrafish is becoming a popular animal model in neuropharmacology and drug discovery, mainly due to its ease of handling and low costs involved in maintenance and experimental work. This animal displays a series of complex behaviours that makes it useful for assessing the effects of psychoactive drugs. Here, adult zebrafish were used for assessment of the anxiolytic and anti-addictive properties of UFR2709, a nicotinic receptor (nAChR) antagonist, using two behavioural paradigms to test for addiction, the novel tank diving test to assess anxiety and the conditioned place preference (CPP). Furthermore, the expression of nAChR subunits α4 and α7 was measured in the zebrafish brain. The results show that UFR2709 exhibits an anxiolytic effect on zebrafish and blocks the effect evoked by nicotine on CPP. Moreover, UFR2709 significantly decreased the expression of α4 nicotinic receptor subunit. This indicates that UFR2709 might be a useful drug for the treatment of nicotine addiction.
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Ansiolíticos/farmacología , Ansiedad/prevención & control , Conducta Animal/efectos de los fármacos , Benzoatos/farmacología , Nicotina/antagonistas & inhibidores , Antagonistas Nicotínicos/farmacología , Pirrolidinas/farmacología , Receptores Nicotínicos/metabolismo , Recompensa , Animales , Ansiedad/inducido químicamente , Modelos Animales de Enfermedad , Nicotina/administración & dosificación , Receptores Nicotínicos/genética , Natación , Pez CebraRESUMEN
The myofibrillar fragmentation index (MFI) is an indicative trait for meat tenderness. Longissimus thoracis muscle samples from the 20 most extreme bulls (out of 80 bulls set) for MFI (high (n = 10) and low (n = 10) groups) trait were used to perform transcriptomic analysis, using RNA Sequencing (RNA-Seq). An average of 24.616 genes was expressed in the Nellore muscle transcriptome analysis. A total of 96 genes were differentially expressed (p value ≤ 0.001) between the two groups of divergent bulls for MFI. The HEBP2 and BDH1 genes were overexpressed in animals with high MFI. The MYBPH and MYL6, myosin encoders, were identified. The differentially expressed genes were related to increase mitochondria efficiency, especially in cells under oxidative stress conditions, and these also were related to zinc and calcium binding, membrane transport, and muscle constituent proteins, such as actin and myosin. Most of those genes were involved in metabolic pathways of oxidation-reduction, transport of lactate in the plasma membrane, and muscle contraction. This is the first study applying MFI phenotypes in transcriptomic studies to identify and understand differentially expressed genes for beef tenderness. These results suggest that differences detected in gene expression between high and low MFI animals are related to reactive mechanisms and structural components of oxidative fibers under the condition of cellular stress. Some genes may be selected as positional candidate genes to beef tenderness, MYL6, MYBPH, TRIM63, TRIM55, TRIOBP, and CHRNG genes. The use of MFI phenotypes could enhance results of meat tenderness studies.
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Bovinos/genética , Músculo Esquelético/metabolismo , Carácter Cuantitativo Heredable , Carne Roja/normas , Transcriptoma , Animales , Bovinos/metabolismo , Proteínas del Citoesqueleto/genética , Proteínas del Citoesqueleto/metabolismo , Perfilación de la Expresión Génica , Proteínas de Unión al Hemo/genética , Proteínas de Unión al Hemo/metabolismo , Masculino , Miosinas/genética , Miosinas/metabolismo , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo , Proteínas de Motivos Tripartitos/genética , Proteínas de Motivos Tripartitos/metabolismoRESUMEN
Genome-wide studies provide increasing evidence of association of genetic variants with different behaviors. However, there is a growing need for replication and subsequent characterization of specific findings. In this sense, the CHRNA5 gene has been associated with nicotine (with genome-wide significance), alcohol and cocaine addictions. So far, this gene has not been evaluated in smoked (crack) cocaine. We aimed to analyze the influence of CHRNA5 variants in crack addiction susceptibility and severity. The sample includes 300 crack-addicted patients and 769 non-addicted individuals. The CHRNA5 SNPs evaluated were rs588765, rs16969968, and rs514743. Homozygosity for rs16969968 and rs588765 major alleles was nominally associated with a risk to crack addiction (GG, P = 0.032; CC, P = 0.036, respectively). Haplotype analyses reveal significant associations (rs588765|rs16969968|rs514743 pglobal-corrected = 7.66 × 10-5) and suggest a substantial role for rs16969968. These findings corroborate previous reports in cocaine addiction-in line with the expected effects of cocaine in the cholinergic system-and in the opposite direction of significant GWAS findings for nicotine addiction susceptibility. These results are strengthened by the first report of an association of rs588765 with crack addiction and by the haplotype findings. In summary, our study highlights the relevance of the α5 subunit on crack cocaine addiction, replicating previous results relating CHRNA5 with the genetics and pathophysiology of addiction of different drugs.
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Trastornos Relacionados con Cocaína/genética , Cocaína Crack/efectos adversos , Proteínas del Tejido Nervioso/genética , Polimorfismo de Nucleótido Simple , Receptores Nicotínicos/genética , Adulto , Alelos , Estudios de Casos y Controles , Trastornos Relacionados con Cocaína/epidemiología , Simulación por Computador , Femenino , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Genotipo , Haplotipos/genética , Humanos , Masculino , Riesgo , Relación Estructura-Actividad , Adulto JovenRESUMEN
INTRODUCTION: Smoking is a leading cause of death, and genetic variation contributes to smoking behaviors. Identifying genes and sets of genes that contribute to risk for addiction is necessary to prioritize targets for functional characterization and for personalized medicine. METHODS: We performed a gene set-based association and heritable enrichment study of two addiction-related gene sets, those on the Smokescreen Genotyping Array and the nicotinic acetylcholine receptors, using the largest available GWAS summary statistics. We assessed smoking initiation, cigarettes per day, smoking cessation, and age of smoking initiation. RESULTS: Individual genes within each gene set were significantly associated with smoking behaviors. Both sets of genes were significantly associated with cigarettes per day, smoking initiation, and smoking cessation. Age of initiation was only associated with the Smokescreen gene set. Although both sets of genes were enriched for trait heritability, each accounts for only a small proportion of the single nucleotide polymorphism-based heritability (2%-12%). CONCLUSIONS: These two gene sets are associated with smoking behaviors, but collectively account for a limited amount of the genetic and phenotypic variation of these complex traits, consistent with high polygenicity. IMPLICATIONS: We evaluated evidence for the association and heritable contribution of expert-curated and bioinformatically identified sets of genes related to smoking. Although they impact smoking behaviors, these specifically targeted genes do not account for much of the heritability in smoking and will be of limited use for predictive purposes. Advanced genome-wide approaches and integration of other 'omics data will be needed to fully account for the genetic variation in smoking phenotypes.
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Conducta Adictiva/genética , Marcadores Genéticos , Estudio de Asociación del Genoma Completo , Polimorfismo de Nucleótido Simple , Receptores Nicotínicos/genética , Fumar/genética , Edad de Inicio , Conducta Adictiva/epidemiología , Conducta Adictiva/psicología , Colorado/epidemiología , Humanos , Fenotipo , Fumar/epidemiología , Fumar/psicologíaRESUMEN
The expansion and pruning of ion channel families has played a crucial role in the evolution of nervous systems. Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels with distinct roles in synaptic transmission at the neuromuscular junction, the central and peripheral nervous system, and the inner ear. Remarkably, the complement of nAChR subunits has been highly conserved along vertebrate phylogeny. To ask whether the different subtypes of receptors underwent different evolutionary trajectories, we performed a comprehensive analysis of vertebrate nAChRs coding sequences, mouse single-cell expression patterns, and comparative functional properties of receptors from three representative tetrapod species. We found significant differences between hair cell and neuronal receptors that were most likely shaped by the differences in coexpression patterns and coassembly rules of component subunits. Thus, neuronal nAChRs showed high degree of coding sequence conservation, coupled to greater coexpression variance and conservation of functional properties across tetrapod clades. In contrast, hair cell α9α10 nAChRs exhibited greater sequence divergence, narrow coexpression pattern, and great variability of functional properties across species. These results point to differential substrates for random change within the family of gene paralogs that relate to the segregated roles of nAChRs in synaptic transmission.
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Evolución Molecular , Receptores Nicotínicos/genética , Vertebrados/genética , Animales , Neuronas Colinérgicas/metabolismo , Células Ciliadas Auditivas/metabolismo , Ratones , Ratas , Receptores Nicotínicos/metabolismoRESUMEN
BACKGROUND: Cigarette consumption has been identified as the main non-etiological factor in head and neck cancer (HNC) development. One of the main compounds in cigarettes is nicotine, which binds directly to nicotine acetylcholine receptors (nAchRs) in the body, which are encoded by different genes of the CHRNA family. Polymorphisms in some of these genes have been studied in relation to the risk of HNC and cigarette consumption intensity. The aim of this study was to evaluate whether there were associations between the CHRNA3 (rs578776) and CHRNA5 (rs16969968) polymorphisms and HNC risk and between the polymorphisms and the intensity of cigarette consumption. METHODS: A total of 1,067 individuals from Heliopolis Hospital in São Paulo were investigated, including 619 patients with HNC and 448 patients without diagnosed tumors. All participants answered a questionnaire about sociodemographic information and cigarette consumption data. The polymorphisms were determined by TaqMan genotyping by real-time PCR. RESULTS: The polymorphisms studied, rs578776 (CHRNA3) and rs16969968 (CHRNA5), did not have an association with HNC risk, but the rs16969968 homozygous genotype was associated with increased cigarette consumption intensity (OR 1.93, 95% CI 1.05-3.58). CONCLUSION: The polymorphism CHRNA5 can be considered an indirect risk factor for neoplasms in these Brazilian samples when cigarette consumption increased.
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Neoplasias de Cabeza y Cuello/genética , Proteínas del Tejido Nervioso/genética , Polimorfismo de Nucleótido Simple , Receptores Nicotínicos/genética , Fumar/epidemiología , Brasil/epidemiología , Estudios de Casos y Controles , Femenino , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Neoplasias de Cabeza y Cuello/inducido químicamente , Heterocigoto , Humanos , Masculino , Fumar/efectos adversos , Encuestas y CuestionariosRESUMEN
INTRODUCTION: Epidemiological studies have described a high comorbidity of substance use disorders with another psychiatric disorder, which has been called dual pathology. However, the aetiological mechanisms underlying this association are still not fully understood. AIM: To carry out a preliminary study of the effect of polymorphism rs1051730 of the gene group CHRNA5-CHRNA3-CHRNB4 through a case-control study. SUBJECTS AND METHODS: A total of 225 subjects were selected and divided into three groups: those diagnosed with bipolar disorder, those with nicotine dependence, and subjects without nicotine dependence or any other psychiatric disorder. Genotyping was performed by real-time polymerase chain reaction. Genetic association analysis was performed using chi-square tests and multivariate logistic regressions. RESULTS: On comparing allelic frequencies with the control group, we found that polymorphism rs1051730 was associated with nicotine dependence (p = 0.03), but not with bipolar disorder (p = 0.94). CONCLUSION: Variant rs1051730 was associated with nicotine dependence in the Mexican population and showed the same effect in dual pathology. However, further studies are recommended to obtain conclusive results.
TITLE: Analisis del polimorfismo rs1051730 de CHRNA3 en pacientes con patologia dual en poblacion mexicana.Introduccion. Estudios epidemiologicos han descrito una alta comorbilidad de los trastornos de uso de sustancias con otro trastorno psiquiatrico, al cual se le ha llamado patologia dual. Sin embargo, los mecanismos etiologicos de esta asociacion continuan siendo dificiles de entender. Objetivo. Realizar un estudio preliminar del efecto del polimorfismo rs1051730 del grupo de genes CHRNA5-CHRNA3-CHRNB4 a traves de un estudio de casos y controles. Sujetos y metodos. Se selecciono a un total de 225 sujetos, divididos en tres grupos: con diagnostico de trastorno bipolar, con dependencia a la nicotina y sujetos sin dependencia a la nicotina o cualquier otro trastorno psiquiatrico. La genotipificacion se realizo mediante reaccion en cadena de la polimerasa en tiempo real. El analisis de asociacion genetica se realizo mediante pruebas de chi cuadrado y regresiones logisticas multivariables. Resultados. Al comparar las frecuencias alelicas con el grupo control, encontramos que el polimorfismo rs1051730 se asocio con el grupo de dependencia a la nicotina (p = 0,03), pero no con el de trastorno bipolar (p = 0,94). Conclusion. La variante rs1051730 se asocio con dependencia a la nicotina en la poblacion mexicana y mostro el mismo efecto en la patologia dual. Sin embargo, se recomiendan estudios adicionales para tener resultados concluyentes.
Asunto(s)
Trastorno Bipolar/genética , Diagnóstico Dual (Psiquiatría) , Polimorfismo Genético , Receptores Nicotínicos/genética , Tabaquismo/genética , Adulto , Trastorno Bipolar/complicaciones , Trastorno Bipolar/diagnóstico , Estudios de Casos y Controles , Femenino , Humanos , Masculino , México , Persona de Mediana Edad , Tabaquismo/diagnóstico , Adulto JovenRESUMEN
Knee osteoarthritis (KOA) is associated with muscle weakness, but it is unclear which structures are involved in the muscle changes. This study assessed morphological alterations and the expression of genes and proteins linked to muscular atrophy and neuromuscular junctions (NMJs) in KOA, induced by anterior cruciate ligament transection (ACLT) in rats. Two groups of rats were assessed: control (without intervention) and KOA (ACLT surgery in the right knee). After 8 weeks, quadriceps, tibialis anterior (TA) and gastrocnemius muscles were analyzed (area of muscle fibers, NMJ, gene and protein expression). KOA group showed atrophy in quadriceps (15.7%) and TA (33%), with an increase in atrogin-1 and muscle RING-finger protein-1 (MuRF-1). KOA group showed quadriceps NMJ remodeling (reduction area and perimeter) and decrease in NMJ diameter in TA muscle. The expression of nicotinic acetylcholine receptor (nAChR) γ-nAChR increased and that of α-nAChR and muscle specific tyrosine kinase (MuSK) declined in the quadriceps, with a decrease in ε-nAChR in TA. MuRF-1 protein expression increased in quadriceps and TA, with no changes in neural cell adhesion molecule (NCAM). In conclusion, ACLT-induced KOA promotes NMJ remodeling and atrophy in quadriceps and TA muscles, associated with inflammatory signs and changes in muscle gene and protein expression.
Asunto(s)
Proteínas Musculares/genética , Músculo Esquelético/metabolismo , Atrofia Muscular/genética , Unión Neuromuscular/metabolismo , Osteoartritis de la Rodilla/genética , Músculo Cuádriceps/metabolismo , Animales , Ligamento Cruzado Anterior/fisiopatología , Ligamento Cruzado Anterior/cirugía , Expresión Génica , Proteínas Musculares/metabolismo , Debilidad Muscular/genética , Debilidad Muscular/metabolismo , Debilidad Muscular/fisiopatología , Músculo Esquelético/fisiopatología , Atrofia Muscular/metabolismo , Atrofia Muscular/fisiopatología , Unión Neuromuscular/fisiopatología , Osteoartritis de la Rodilla/metabolismo , Osteoartritis de la Rodilla/fisiopatología , Músculo Cuádriceps/fisiopatología , Ratas Wistar , Proteínas Tirosina Quinasas Receptoras/genética , Proteínas Tirosina Quinasas Receptoras/metabolismo , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo , Proteínas Ligasas SKP Cullina F-box/genética , Proteínas Ligasas SKP Cullina F-box/metabolismo , Proteínas de Motivos Tripartitos/genética , Proteínas de Motivos Tripartitos/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
Nematode parasites cause substantial morbidity to billions of people and considerable losses in livestock and food crops. The repertoire of effective anthelmintic compounds for treating these parasitoses is very limited, as drug development has been delayed for decades. Moreover, resistance has become a global concern in livestock parasites and is an emerging issue for human helminthiasis. Therefore, anthelmintics with novel mechanisms of action are urgently needed. Taking advantage of Caenorhabditis elegans as an established model system, we here screened the nematicidal potential of novel imidazolium and imidazole derivatives. One of these derivatives, diisopropylphenyl-imidazole (DII), is lethal to C. elegans at both mature and immature stages. This lethal effect appears to be specific because DII concentrations which prove to be toxic to C. elegans do not induce significant lethality on bacteria, Drosophila melanogaster, and HEK-293 cells. Our analysis of DII action on C. elegans mutant strains determined that, in the adult stage, null mutants of unc-29 are resistant to the drug. Muscle expression of this gene completely restores DII sensitivity. UNC-29 has been largely reported as an essential constituent of the levamisole-sensitive muscle nicotinic receptor (L-AChR). Nevertheless, null mutants in unc-63 and lev-8 (essential and non-essential subunits of L-AChRs, respectively) are as sensitive to DII as the wild-type strain. Therefore, our results suggest that DII effects on adult nematodes rely on a previously unidentified UNC-29-containing muscle AChR, different from the classical L-AChR. Interestingly, DII targets appear to be different between larvae and adults, as unc-29 null mutant larvae are sensitive to the drug. The existence of more than one target could delay resistance development. Its lethality on C. elegans, its harmlessness in non-nematode species and its novel and dual mechanism of action make DII a promising candidate compound for anthelmintic therapy.