RESUMEN
Type 2 diabetes mellitus (T2DM) is a complex chronic disease characterized by decreased insulin secretion and the development of insulin resistance. Previous genome-wide association studies demonstrated that single-nucleotide polymorphisms (SNPs) present in genes coding for ion channels involved in insulin secretion increase the risk of developing this disease. We determined the association of 16 SNPs found in CACNA1D, KCNQ1, KCNJ11, and CACNA1E genes and the increased probability of developing T2DM. In this work, we performed a case-control study in 301 Mexican adults, including 201 cases with diabetes and 100 controls without diabetes. Our findings indicate a moderate association between T2DM and the C allele, and the C/C genotype of rs312480 within CACNA1D. The CAG haplotype surprisingly showed a protective effect, whereas the CAC and CGG haplotypes have a strong association with T2DM. The C allele and C/C genotype of rs5219 were significantly associated with diabetes. Also, an association was observed between diabetes and the A allele and the A/A genotype of rs3753737 and rs175338 in CACNA1E. The TGG and CGA haplotypes were also found to be significantly associated. The findings of this study indicate that the SNPs examined could serve as a potential diagnostic tool and contribute to the susceptibility of the Mexican population to this disease.
Asunto(s)
Canales de Calcio Tipo L , Diabetes Mellitus Tipo 2 , Predisposición Genética a la Enfermedad , Canal de Potasio KCNQ1 , Polimorfismo de Nucleótido Simple , Canales de Potasio de Rectificación Interna , Humanos , Diabetes Mellitus Tipo 2/genética , Canales de Calcio Tipo L/genética , Canal de Potasio KCNQ1/genética , Femenino , Masculino , Canales de Potasio de Rectificación Interna/genética , Persona de Mediana Edad , Estudios de Casos y Controles , Adulto , Haplotipos , Canales de Calcio Tipo R/genética , Alelos , México , Anciano , Estudios de Asociación Genética , Genotipo , Frecuencia de los Genes , Proteínas de Transporte de CatiónRESUMEN
Sexual dimorphism among mammals includes variations in the pain threshold. These differences are influenced by hormonal fluctuations in females during the estrous and menstrual cycles of rodents and humans, respectively. These physiological conditions display various phases, including proestrus and diestrus in rodents and follicular and luteal phases in humans, distinctly characterized by varying estrogen levels. In this study, we evaluated the capsaicin responses in male and female mice at different estrous cycle phases, using two murine acute pain models. Our findings indicate that the capsaicin-induced pain threshold was lower in the proestrus phase than in the other three phases in both pain assays. We also found that male mice exhibited a higher pain threshold than females in the proestrus phase, although it was similar to females in the other cycle phases. We also assessed the mRNA and protein levels of TRPV1 in the dorsal root and trigeminal ganglia of mice. Our results showed higher TRPV1 protein levels during proestrus compared to diestrus and male mice. Unexpectedly, we observed that the diestrus phase was associated with higher TRPV1 mRNA levels than those in both proestrus and male mice. These results underscore the hormonal influence on TRPV1 expression regulation and highlight the role of sex steroids in capsaicin-induced pain.
Asunto(s)
Capsaicina , Dolor , Canales Catiónicos TRPV , Animales , Canales Catiónicos TRPV/metabolismo , Canales Catiónicos TRPV/genética , Capsaicina/farmacología , Masculino , Femenino , Ratones , Dolor/metabolismo , Dolor/genética , Hormonas Esteroides Gonadales/metabolismo , Ciclo Estral/efectos de los fármacos , Umbral del Dolor/efectos de los fármacos , Ganglios Espinales/metabolismo , Ganglios Espinales/efectos de los fármacos , Ganglio del Trigémino/metabolismo , Ganglio del Trigémino/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Caracteres Sexuales , ARN Mensajero/metabolismo , ARN Mensajero/genéticaRESUMEN
The primary function of dystrophin is to form a link between the cytoskeleton and the extracellular matrix. In addition to this crucial structural function, dystrophin also plays an essential role in clustering and organizing several signaling proteins, including ion channels. Proteomic analysis of the whole rodent brain has stressed the role of some components of the dystrophin-associated glycoprotein complex (DGC) as potential interacting proteins of the voltage-gated Ca2+ channels of the CaV2 subfamily. The interaction of CaV2 with signaling and scaffolding proteins, such as the DGC components, may influence their function, stability, and location in neurons. This work aims to study the interaction between dystrophin and CaV2.1. Our immunoprecipitation data showed the presence of a complex formed by CaV2.1, CaVα2δ-1, CaVß4e, Dp140, and α1-syntrophin in the brain. Furthermore, proximity ligation assays (PLA) showed that CaV2.1 and CaVα2δ-1 interact with dystrophin in the hippocampus and cerebellum. Notably, Dp140 and α1-syntrophin increase CaV2.1 protein stability, half-life, permanence in the plasma membrane, and current density through recombinant CaV2.1 channels. Therefore, we have identified the Dp140 and α1-syntrophin as novel interaction partners of CaV2.1 channels in the mammalian brain. Consistent with previous findings, our work provides evidence of the role of DGC in anchoring and clustering CaV channels in a macromolecular complex.
Asunto(s)
Distrofina , Proteómica , Animales , Distrofina/genética , Distrofina/metabolismo , Mamíferos/metabolismo , Neuronas/metabolismoRESUMEN
The Transient Receptor Vanilloid 1 (TRPV1) or capsaicin receptor is a nonselective cation channel, which is abundantly expressed in nociceptors. This channel is an important transducer of several noxious stimuli, having a pivotal role in pain development. Several TRPV1 studies have focused on understanding its structure and function, as well as on the identification of compounds that regulate its activity. The intracellular roles of these channels have also been explored, highlighting TRPV1's actions in the homeostasis of Ca2+ in organelles such as the mitochondria. These studies have evidenced how the activation of TRPV1 affects mitochondrial functions and how this organelle can regulate TRPV1-mediated nociception. The close relationship between this channel and mitochondria has been determined in neuronal and non-neuronal cells, demonstrating that TRPV1 activation strongly impacts on cell physiology. This review focuses on describing experimental evidence showing that TRPV1 influences mitochondrial function.
Asunto(s)
Señalización del Calcio/genética , Mitocondrias/genética , Dolor/genética , Canales Catiónicos TRPV/genética , Animales , Calcio/metabolismo , Humanos , Mitocondrias/metabolismo , Nocicepción/fisiología , Dolor/fisiopatología , Transducción de Señal/genéticaRESUMEN
Transient Receptor Potential (TRP) channels are a family of ion channels whose members are distributed among all kinds of animals, from invertebrates to vertebrates. The importance of these molecules is exemplified by the variety of physiological roles they play. Perhaps, the most extensively studied member of this family is the TRPV1 ion channel; nonetheless, the activity of TRPV4 has been associated to several physio and pathophysiological processes, and its dysfunction can lead to severe consequences. Several lines of evidence derived from animal models and even clinical trials in humans highlight TRPV4 as a therapeutic target and as a protein that will receive even more attention in the near future, as will be reviewed here.
Asunto(s)
Canales Catiónicos TRPV/fisiología , Animales , Calcio/metabolismo , Bovinos , Endotelio Vascular/metabolismo , Humanos , Riñón/metabolismo , Ratones , Microcirculación , Dolor/metabolismo , Permeabilidad , Pronóstico , Dominios Proteicos , Ratas , Vasos Retinianos , Piel/metabolismoRESUMEN
The Transient Receptor Potential Vanilloid 1 (TRPV1) channel is a polymodal protein with functions widely linked to the generation of pain. Several agonists of exogenous and endogenous nature have been described for this ion channel. Nonetheless, detailed mechanisms and description of binding sites have been resolved only for a few endogenous agonists. This review focuses on summarizing discoveries made in this particular field of study and highlighting the fact that studying the molecular details of activation of the channel by different agonists can shed light on biophysical traits that had not been previously demonstrated.
Asunto(s)
Activación del Canal Iónico , Dominios Proteicos , Canales Catiónicos TRPV/química , Canales Catiónicos TRPV/metabolismo , Animales , Sitios de Unión/genética , Humanos , Ligandos , Modelos Moleculares , Unión Proteica , Canales Catiónicos TRPV/genéticaRESUMEN
Transient receptor potential (TRP) channels are remarkable transmembrane protein complexes that are essential for the physiology of the tissues in which they are expressed. They function as non-selective cation channels allowing for the signal transduction of several chemical, physical and thermal stimuli and modifying cell function. These channels play pivotal roles in the nervous and reproductive systems, kidney, pancreas, lung, bone, intestine, among others. TRP channels are finely modulated by different mechanisms: regulation of their function and/or by control of their expression or cellular/subcellular localization. These mechanisms are subject to being affected by several endogenously-produced compounds, some of which are of a lipidic nature such as steroids. Fascinatingly, steroids and TRP channels closely interplay to modulate several physiological events. Certain TRP channels are affected by the typical genomic long-term effects of steroids but others are also targets for non-genomic actions of some steroids that act as direct ligands of these receptors, as will be reviewed here.
Asunto(s)
Andrógenos/metabolismo , Estrógenos/metabolismo , Canales de Potencial de Receptor Transitorio/metabolismo , Animales , Humanos , Canales de Potencial de Receptor Transitorio/química , Canales de Potencial de Receptor Transitorio/genéticaRESUMEN
Ion channels constitute a varied class of membrane proteins with pivotal roles in cellular physiology and that are fundamental for neuronal signaling, hormone secretion and muscle contractility. Hence, it is not unanticipated that toxins from diverse organisms have evolved to modulate the activity of ion channels. For instance, animals such as cone snails, scorpions, spiders and snakes use toxins to immobilize and capture their prey by affecting ion channel function. This is a beautiful example of an evolutionary process that has led to the development of an injection apparatus from predators and to the existence of toxins with high affinity and specificity for a given target. Toxins have been used in the field of ion channel biophysics for several decades to gain insight into the gating mechanisms and the structure of ion channels. Through the use of these peptides, much has been learned about the ion conduction pathways, voltage-sensing mechanisms, pore sizes, kinetics, inactivation processes, etc. This review examines an assortment of toxins that have been used to study different ion channels and describes some key findings about the structure-function relationships in these proteins through the details of the toxin-ion channel interactions.
Asunto(s)
Canales Iónicos/química , Canales Iónicos/metabolismo , Toxinas Biológicas/química , Toxinas Biológicas/farmacología , Animales , Humanos , Activación del Canal Iónico/efectos de los fármacos , Canales Iónicos/antagonistas & inhibidores , Ligandos , Modelos Moleculares , Conformación Proteica , Subunidades de Proteína , Relación Estructura-ActividadRESUMEN
In this study, we delineated the molecular mechanisms that modulate Dp71 expression during neuronal differentiation, using the N1E-115 cell line. We demonstrated that Dp71 expression is up-regulated in response to cAMP-mediated neuronal differentiation of these cells, and that this induction is controlled at promoter level. Functional deletion analysis of the Dp71 promoter revealed that a 5'-flanking 159-bp DNA fragment that contains Sp1 and AP2 binding sites is necessary and sufficient for basal expression of this TATA-less promoter, as well as for its induction during neuronal differentiation. Electrophoretic mobility shift and chromatin immunoprecipitation assays revealed that Sp1 and AP2alpha bind to their respective DNA elements within the Dp71 basal promoter. Overall, mutagenesis assays on the Sp1 and AP2 binding sites, over-expression of Sp1 and AP2alpha, as well as knock-down experiments on Sp1 and AP2alpha gene expression established that Dp71 basal expression is controlled by the combined action of Sp1 and AP2alpha, which act as activator and repressor, respectively. Furthermore, we demonstrated that induction of Dp71 expression in differentiated cells is the result of the maintenance of positive regulation exerted by Sp1, as well as of the loss of AP2alpha binding, which ultimately releases the promoter from repression.
Asunto(s)
Diferenciación Celular/fisiología , Proteínas de Unión al ADN/metabolismo , Distrofina/metabolismo , Inmunoglobulinas/metabolismo , Neuronas/fisiología , Animales , Encéfalo/citología , Bucladesina/farmacología , Diferenciación Celular/efectos de los fármacos , Cloranfenicol O-Acetiltransferasa/metabolismo , Inmunoprecipitación de Cromatina/métodos , Dimetilsulfóxido/farmacología , Ensayo de Cambio de Movilidad Electroforética/métodos , Proteínas de Unión a Ácidos Grasos , Depuradores de Radicales Libres/farmacología , Ratones , Mutagénesis Sitio-Dirigida/métodos , Neuroblastoma , Neuronas/efectos de los fármacos , Óxido Nítrico Sintasa de Tipo I/metabolismo , Regiones Promotoras Genéticas/efectos de los fármacos , ARN Interferente Pequeño/farmacología , Transfección/métodos , Regulación hacia Arriba/fisiología , beta-Galactosidasa/metabolismoRESUMEN
Dp71 expression is present in myoblasts but declines during myogenesis to avoid interfering with the function of dystrophin, the predominant Duchenne muscular dystrophy gene product in differentiated muscle fibers. To elucidate the transcriptional regulatory mechanisms operating on the developmentally regulated expression of Dp71, we analyzed the Dp71 expression and promoter activity during myogenesis of the C2C12 cells. We demonstrated that the cellular content of Dp71 transcript and protein decrease in myotubes as a consequence of the negative regulation that the differentiation stimulus exerts on the Dp71 promoter. Promoter deletion analysis showed that the 224-bp 5'-flanking region, which contains several Sp-binding sites (Sp-A to Sp-D), is responsible for the Dp71 promoter basal activity in myoblasts as well as for down-regulation of the promoter in differentiated cells. Electrophoretic mobility shift and chromatin immunoprecipitation assays indicated that Sp1 and Sp3 transcription factors specifically bind to the Sp-binding sites in the minimal Dp71 promoter region. Site-directed mutagenesis assay revealed that Sp-A is the most important binding site for the proximal Dp71 promoter activity. Additionally, cotransfection of the promoter construct with Sp1- and Sp3-expressing vectors into Drosophila SL2 cells, which lack endogenous Sp family, confirmed that these proteins activate specifically the minimal Dp71 promoter. Endogenous Sp1 and Sp3 proteins were detected only in myoblasts and not in myotubes, which indicates that the lack of these factors causes down-regulation of the Dp71 promoter activity in differentiated cells. In corroboration, efficient promoter activity was restored in differentiated muscle cells by exogenous expression of Sp1 and Sp3.