RESUMO
Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infections worldwide, yet no effective vaccine or antiviral treatment is available. Here we report the discovery and initial development of RSV604, a novel benzodiazepine with submicromolar anti-RSV activity. It proved to be equipotent against all clinical isolates tested of both the A and B subtypes of the virus. The compound has a low rate of in vitro resistance development. Sequencing revealed that the resistant virus had mutations within the nucleocapsid protein. This is a novel mechanism of action for anti-RSV compounds. In a three-dimensional human airway epithelial cell model, RSV604 was able to pass from the basolateral side of the epithelium effectively to inhibit virus replication after mucosal inoculation. RSV604, which is currently in phase II clinical trials, represents the first in a new class of RSV inhibitors and may have significant potential for the effective treatment of RSV disease.
Assuntos
Antivirais/farmacologia , Benzodiazepinonas/farmacologia , Compostos de Fenilureia/farmacologia , Vírus Sinciciais Respiratórios/efeitos dos fármacos , Sequência de Aminoácidos , Antivirais/síntese química , Benzodiazepinonas/síntese química , Linhagem Celular , Fenômenos Químicos , Físico-Química , Efeito Citopatogênico Viral , Relação Dose-Resposta a Droga , Farmacorresistência Viral/genética , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/virologia , Humanos , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Mutação , Proteínas do Nucleocapsídeo/efeitos dos fármacos , Compostos de Fenilureia/síntese química , Vírus Sinciciais Respiratórios/genética , Sais de Tetrazólio , Replicação Viral/efeitos dos fármacosRESUMO
The effect of Y-26763 [(-)-(3S,4R)-4-(N-acetyl-N-hydroxyamino)-6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-3-ol], a novel ATP-sensitive K(+) (K(ATP)) channel activator, was tested on insulin secretion from human pancreatic islets in vitro. Y-26763 was able to inhibit both glucose- and tolbutamide-induced insulin secretion from islets as assessed by radioimmunoassay. The mechanism for inhibition of insulin secretion was characterised using patch clamp electrophysiology on dispersed human pancreatic beta-cells which express K(ATP) channels comprised of Kir6.2 and SUR1, and the NES2Y human beta-cell line, transfected with Kir6.2DeltaC26. Y-26763 activated K(ATP) channels in a reversible manner with a similar activity to diazoxide. This required the presence of hydrolysable nucleotides and appeared to be mediated by interaction of Y-26763 with SUR1 since: (a) tolbutamide was able to reverse the actions of Y-26763 and (b) Y-26763 failed to activate Kir6.2DeltaC26 in the absence of SUR1. We conclude that Y-26763-induced inhibition of insulin release is dependent upon the activation of K(ATP) channels in human beta-cells.