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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.

Cette invention concerne des peptidomimetiques en epingle a cheveux s de formule generale cyclo(-Xaa 1 -Xaa 2 -Xaa 3 -Cys 4 -Xaa 5 -Xaa 6 -Xaa 7 -Xaa 8 -Arg 9 -Tyr 10 -Cys 11 - Xaa 12 -Xaa 13 -Xaa 14 -Xaa 15 -Xaa 16 -), un pont disulfure situe entre Cys 4 et Cys11, et leurs sels pharmaceutiquement acceptables, Xaa 1 , Xaa 2 , Xaa 3 , Xaa 5 , Xaa 6 , Xaa 7 , Xaa 8 , Xaa 12 , Xaa 13 , Xaa 14 , Xaa 15 et Xaa 16 etant des residus d'acides amines de types specifiques qui sont definis dans la description et les revendications. Ces peptidomimetiques presentent des proprietes antagonistes par rapport au recepteur CXCR4 et peuvent etre utilises pour prevenir des infections a VIH chez des sujets sains, ou pour ralentir et stopper la progression virale chez des patients infectes; ils peuvent aussi etre utilises dans le cas d'un cancer medie par une activite du recepteur CXCR4 ou resultant d'une telle activite; ou dans le cas de maladies immunologiques mediees par une activite du recepteur CXCR4 ou resultant d'une telle activite; ou pour traiter une immunosuppression; ou lors de collectes par apherese de cellules souches dans le sang peripherique et/ou en tant qu'agents pour induire une mobilisation de cellules souches et reguler la reparation tissulaire. Ces peptides peuvent etre fabriques par un procede base sur une strategie de synthese a phase mixte solide-solution.

Novel, highly potent CXCR4 inhibitors with good pharmacokinetic properties were obtained by applying PEM technology starting from the naturally occurring ?-hairpin peptide polyphemusin II. The design involved incorporation of key residues from polyphemusin II into a macrocyclic template-bound ?-hairpin mimetic. Using a parallel synthesis approach, the potency and ADME properties of the mimetics were optimized, resulting in CXCR4 inhibitors such as POL2438 and POL3026. Their activities were confirmed in a series of in vitro HIV-1 infection assays. Besides high selectivity for CXCR4, POL3026 had excellent plasma stability and favorable pharmacokinetic properties in dogs. In a murine model POL3026 was highly efficacious in hematopoietic stem cell mobilization. Hence, PEM-based CXCR4 inhibitors have the potential to become therapeutic agents for the treatment of HIV infections (as entry inhibitor), cancer (e.g. for inhibition of metastasis), stem cell transplant and inflammation.

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.