RESUMEN
Novel series of sphingosine-1-phosphate (S1P) receptor agonists were developed through a systematic SAR aimed to achieve high selectivity for a single member of the S1P family of receptors, S1P1. The optimized structure represents a highly S1P1-selective and efficacious agonist: S1P1/S1P2, S1P1/S1P3, S1P1/S1P4>10,000-fold, S1P1/S1P5>600-fold, while EC50 (S1P1) <0.2 nM. In vivo experiments are consistent with S1P1 receptor agonism alone being sufficient for achieving desired lymphocyte-lowering effect.
Asunto(s)
Inmunosupresores/síntesis química , Inmunosupresores/farmacología , Linfocitos/efectos de los fármacos , Receptores de Lisoesfingolípidos/agonistas , Animales , Células CHO , Cricetinae , Recuento de Linfocitos , Linfocitos/citología , Relación Estructura-ActividadRESUMEN
The m7GpppN cap at the 5' end of eukaryotic mRNAs is important for transcript stability and translation. Three enzymatic activities that generate the mRNA cap include an RNA 5'-triphosphatase, an RNA guanylyltransferase, and an RNA (guanine-7-) -methyltransferase. The physical organization of the genes encoding these enzymes differs between mammalian cells and yeast, fungi, or viruses. The catalytic mechanism used by the RNA triphosphatases of mammalian cells also differs from that used by the yeast, fungal, or viral enzymes. These structural and functional differences suggest that inhibitors of mRNA capping might be useful antifungal or antiviral agents. The authors describe several whole-cell yeast-based assays developed to identify and characterize inhibitors of fungal mRNA capping. They also report the identification and characterization of the natural product sinefungin in the assays. Their characterization of this S-adenosylmethionine analog suggests that it inhibits mRNA cap methyltransferases and exhibits approximately 5- to 10-fold specificity for the yeast ABD1 and fungal CCM1 enzymes over the human Hcm1 enzyme expressed in yeast cells.
Asunto(s)
Adenosina/análogos & derivados , Inhibidores Enzimáticos/análisis , Nucleotidiltransferasas/antagonistas & inhibidores , Saccharomyces cerevisiae/genética , Adenosina/química , Secuencia de Aminoácidos , Genes Reporteros , Datos de Secuencia Molecular , Nucleotidiltransferasas/química , Nucleotidiltransferasas/genética , Plásmidos , Homología de Secuencia de AminoácidoRESUMEN
The novel immunosuppressive agent FTY720 (1) is phosphorylated in vivo in a variety of species yielding an active metabolite that is an agonist of four of the five known G-protein-coupled sphingosine-1-phosphate (S1P) receptors. A synthesis amenable to producing gram quantities of the stereoisomeric phosphate esters, a determination of their absolute stereochemistry via an enantioselective synthesis and their characterization as S1P receptor agonists and antagonists is reported.
