Biological Activity
many bacterial pathogens rely on a conserved membrane histidine sensor kinase, qsec, to respond to host adrenergic signaling molecules and bacterial signals in order to promote the expression of virulence factors. led209 is a potent prodrug that is highly selective for qsec.
in vitro
led209-mediated inhibition of virulence gene expression inhibited the secretion of espa and espb, two proteins encoded within the locus of enterocyte effacement that are required for escherichia coli (ehec) to translocate bacterial proteins into host cells and cause attaching-effacing (ae) lesions. at 5 pm, led209 abolished ehec ae lesion formation on cultured epithelial cells. unlike conventional antibiotics, led209 does not kill or hinder ehec growth or trigger the ehec sos response [1].
in vivo
led209 [20 mg per kilogram of body weight (mg/kg)] was given orally to mice 3 hours before and 3 hours after intraperitoneal injection of a lethal dose of s. typhimurium. twenty-four hours after infection, only 30% of untreated mice remained alive, whereas 80% of the led209-treated mice were still alive. all the s. typhimurium– infected mice died within 72 hours of infection, and 20% of led209-treated mice survived up to 12 days [1].
References
[1] rasko da, moreira cg, li de r, reading nc, ritchie jm, waldor mk, williams n, taussig r, wei s, roth m, hughes dt, huntley jf, fina mw, falck jr, sperandio v. targeting qsec signaling and virulence for antibiotic development. science. 2008 aug 22;321(5892):1078-80.
