RESUMEN
Propionibacterium acnes is a key therapeutic target in acne, yet this bacterium has become resistant to standard antibiotic agents. We investigated whether the human antimicrobial protein granulysin is a potential candidate for the treatment of acne. Granulysin and synthetic granulysin-derived peptides possessing a helix-loop-helix motif killed P. acnes in vitro. Modification of a helix-loop-helix peptide, 31-50, by substitution of a tryptophan for the valine at amino acid 44 (peptide 31-50v44w) to increase its interaction with bacterial surfaces also increased its antimicrobial activity. Moreover, when synthesized with D- rather than L-type amino acids, this peptide (D-31-50v44w) became less susceptible to degradation by proteases and more effective in killing P. acnes. Granulysin peptides were bactericidal, demonstrating an advantage over standard bacteriostatic antibiotics in their control of P. acnes. Moreover, peptide D-31-50v44w killed P. acnes in isolated human microcomedone preparations. Importantly, peptides 31-50, 31-50v44w, and D-31-50v44w also have potential anti-inflammatory effects, as demonstrated by suppression of P. acnes-stimulated cytokine release. Taken together, these data suggest that granulysin peptides may be useful as topical therapeutic agents, providing alternatives to current acne therapies.
Asunto(s)
Acné Vulgar/tratamiento farmacológico , Antiinfecciosos/farmacología , Antiinflamatorios/farmacología , Antígenos de Diferenciación de Linfocitos T/farmacología , Propionibacterium acnes/efectos de los fármacos , Acné Vulgar/inmunología , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Antígenos de Diferenciación de Linfocitos T/química , Antígenos de Diferenciación de Linfocitos T/genética , Citocinas/metabolismo , Secuencias Hélice-Asa-Hélice/genética , Humanos , Técnicas In Vitro , Monocitos/metabolismo , Monocitos/microbiología , Fragmentos de Péptidos/química , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/farmacologíaAsunto(s)
Infecciones Bacterianas/inmunología , Proteínas de Drosophila , Glicoproteínas de Membrana/fisiología , Receptores de Superficie Celular/fisiología , Animales , Infecciones Bacterianas/metabolismo , Humanos , Infecciones , Mamíferos , Receptores de Superficie Celular/genética , Receptores Inmunológicos/inmunología , Transducción de Señal , Receptores Toll-LikeRESUMEN
As pattern recognition receptors capable of eliciting responses to a diverse array of microbial products, Toll-like receptors (TLRs) participate in the activation of host defense mechanisms that protect against infectious pathogens. Given that epithelial cells lie at the interface between the host and its environment, we designed experiments to determine whether human airway epithelial cells express TLRs and respond to TLR agonists. Immunohistochemical labeling of TLR2 in normal human airways revealed TLR2 expression throughout the epithelium, with an apparently higher level of expression on noncolumnar basal epithelial cells. Two-color immunofluorescent labeling of TLR2 and cytokeratins 8 and 15 revealed that TLR2 is coexpressed with the epithelial cell markers. In addition, airway epithelial cells grown at air-liquid interface responded to bacterial lipopeptide in a TLR2-dependent manner with induction of mRNA and protein of the antimicrobial peptide human beta defensin-2. Stimulation of epithelial cell cultures with lipopeptide resulted in a small and variable reduction of bacteria on the apical surface. Together, these data suggest that TLRs monitor epithelial surfaces to enhance host defense by inducing the production of an antimicrobial peptide.