RESUMO
The bovine CaCC protein is a putative Ca2+-dependent Cl- channel of airway epithelial cells. Therefore, CaCC proteins could contribute to transepithelial Cl- transport and accordingly modify the phenotype of cystic fibrosis (CF) patients. We have identified a murine EST containing a full-length cDNA coding for a 902-amino-acid protein highly homologous to bovine CaCC. The murine gene (mCaCC) maps to chromosome 3 at the H2-H3 band and is expressed, as indicated by Northern blot analysis, in mouse skin and kidney but not in brain, heart, lung or testis. RT-PCR indicates a low expression in tracheal epithelial cells. Heterologous expression of mCaCC in Xenopus oocytes elicits membrane currents that are anion-selective and inhibited by DIDS and by niflumic acid, a blocker of the endogenous chloride current in oocytes. The identification of genes belonging to the CaCC family will help to evaluate their role as ion channels or channel regulators and their actual contribution to epithelial chloride transport.
Assuntos
Cálcio/fisiologia , Canais de Cloreto/genética , Genes/genética , Ácido 4,4'-Di-Isotiocianoestilbeno-2,2'-Dissulfônico/farmacologia , Sequência de Aminoácidos , Animais , Northern Blotting , Bovinos , Canais de Cloreto/administração & dosagem , Mapeamento Cromossômico , Etiquetas de Sequências Expressas , Feminino , Expressão Gênica , Hibridização in Situ Fluorescente , Ionomicina/farmacologia , Ionóforos/farmacologia , Masculino , Potenciais da Membrana/efeitos dos fármacos , Camundongos , Microinjeções , Dados de Sequência Molecular , Ácido Niflúmico/farmacologia , Oócitos/citologia , Oócitos/efeitos dos fármacos , Oócitos/fisiologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Alinhamento de Sequência , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Cloreto de Sódio/farmacologia , Distribuição Tecidual , XenopusRESUMO
No effective treatment was available for myotonic dystrophy, even in animal model. We have established a new antisense oligonucleotide delivery to skeletal muscle of mice with bubble liposomes, and led to increased expression of chloride channel (CLCN1) protein and the amelioration of myotonia. In other experiments, we also identified small molecule compounds that correct aberrant splicing of Clcn1 gene. Manumycin A corrected aberrant splicing of Clcn1 in mouse model.
Assuntos
Distrofia Miotônica , Animais , Canais de Cloreto/administração & dosagem , Canais de Cloreto/genética , Canais de Cloreto/metabolismo , Modelos Animais de Doenças , Técnicas de Transferência de Genes , Terapia Genética/métodos , Humanos , Lipossomos , Camundongos , Terapia de Alvo Molecular , Músculo Esquelético , Distrofia Miotônica/genética , Distrofia Miotônica/terapia , Oligonucleotídeos Antissenso/administração & dosagem , Polienos/farmacologia , Polienos/uso terapêutico , Alcamidas Poli-Insaturadas/farmacologia , Alcamidas Poli-Insaturadas/uso terapêutico , Splicing de RNA/efeitos dos fármacosRESUMO
The nutritional value of glycerol-1,2,3-tris(methylsuccinate), a novel ester of succinic acid with high insulinotropic efficiency both in vitro and in vivo, was assessed in both fed and starved rats. The infusion of the ester, given in a daily amount (1.2 micromol. g body wt-1) well in excess of what could result from its repeated intravenous administration as an insulinotropic agent in non-insulin-dependent diabetes (0.07 micromol. g body wt-1 for each administration), failed to prevent the fall in body weight, liver and muscle glycogen contents, and plasma d-glucose or insulin concentration, as well as the increase in plasma free fatty acid and beta-hydroxybutyrate concentrations caused by starvation. The sole indications that the ester may serve, to a limited extent, as an alternative nutrient in starved rats consisted in a somewhat higher weight of both liver and paraovarian adipose tissue and somewhat higher activity of liver glucokinase in rats receiving the ester than in animals infused with saline. The low nutritional value of this ester thus answers the objection of its possible role as an extrapancreatic nutrient or gluconeogenic precursor in the perspective of its use as an insulinotropic tool in type 2 diabetes.