RESUMO
Antibiotics with new mechanisms of action are urgently required to combat the growing health threat posed by resistant pathogenic microorganisms. We synthesized a family of peptidomimetic antibiotics based on the antimicrobial peptide protegrin I. Several rounds of optimization gave a lead compound that was active in the nanomolar range against Gram-negative Pseudomonas spp., but was largely inactive against other Gram-negative and Gram-positive bacteria. Biochemical and genetic studies showed that the peptidomimetics had a non-membrane-lytic mechanism of action and identified a homolog of the beta-barrel protein LptD (Imp/OstA), which functions in outer-membrane biogenesis, as a cellular target. The peptidomimetic showed potent antimicrobial activity in a mouse septicemia infection model. Drug-resistant strains of Pseudomonas are a serious health problem, so this family of antibiotics may have important therapeutic applications.
Assuntos
Antibacterianos/farmacologia , Proteínas da Membrana Bacteriana Externa/metabolismo , Membrana Celular/metabolismo , Peptídeos/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/metabolismo , Animais , Antibacterianos/síntese química , Antibacterianos/metabolismo , Peptídeos Catiônicos Antimicrobianos/química , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/genética , Desenho de Fármacos , Farmacorresistência Bacteriana/genética , Genes Bacterianos , Lipopolissacarídeos/metabolismo , Camundongos , Testes de Sensibilidade Microbiana , Mimetismo Molecular , Mutação , Biblioteca de Peptídeos , Peptídeos/síntese química , Peptídeos/química , Peptídeos/metabolismo , Estrutura Terciária de Proteína , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/ultraestrutura , Sepse/tratamento farmacológico , Sepse/microbiologiaRESUMO
Novel highly potent CXCR4 inhibitors with good pharmacokinetic properties were designed and optimized starting from the naturally occurring beta-hairpin peptide polyphemusin II. The design involved incorporating important residues from polyphemusin II into a macrocyclic template-bound beta-hairpin mimetic. Using a parallel synthesis approach, the potency and ADME properties of the mimetics were optimized in iterative cycles, resulting in the CXCR4 inhibitors POL2438 and POL3026. The inhibitory potencies of these compounds were confirmed in a series of HIV-1 invasion assays in vitro. POL3026 showed excellent plasma stability, high selectivity for CXCR4, favorable pharmacokinetic properties in the dog, and thus has the potential to become a therapeutic compound for application in the treatment of HIV infections (as an entry inhibitor), cancer (for angiogenesis suppression and inhibition of metastasis), inflammation, and in stem cell transplant therapy.
