Park N, Yamanaka K, Tran D, Chandrangsu P, Akers JC, de Leon JC, Morrissette NS, Selsted ME, Tan M. The cell-penetrating peptide, Pep-1, has activity against intracellular chlamydial growth but not extracellular forms of Chlamydia trachomatis.
J Antimicrob Chemother 2009;
63:115-23. [PMID:
18957395 PMCID:
PMC2721699 DOI:
10.1093/jac/dkn436]
[Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Revised: 09/12/2008] [Accepted: 09/24/2008] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES
In the course of studies to identify novel treatment strategies against the pathogenic bacterium, Chlamydia, we tested the carrier peptide, Pep-1, for activity against an intracellular infection.
METHODS
Using a cell culture model of Chlamydia trachomatis infection, the effect of Pep-1 was measured by incubating the peptide with extracellular chlamydiae prior to infection, or by adding Pep-1 to the medium at varying times after infection, and assaying for inhibition of inclusion formation.
RESULTS
Pep-1 had a concentration-dependent effect on chlamydial growth with 100% inhibition of inclusion formation at 8 mg/L peptide. There was a window of susceptibility during the chlamydial developmental cycle with a maximal effect when treatment was begun within 12 h of infection. Pep-1 treatment caused a severe reduction in the production of infectious progeny even when started later, when the effect on inclusion formation was minimal. Furthermore, electron micrographs showed a paucity of progeny elementary bodies (EBs) in the inclusion. In contrast, pre-incubation of EBs with Pep-1 prior to infection did not affect inclusion formation. Taken together, these findings indicate that the antichlamydial effect was specific for the intracellular stage of chlamydial infection. By comparison, Pep-1 had no antimicrobial activity against Escherichia coli and Staphylococcus aureus or the obligate intracellular parasite, Toxoplasma gondii.
CONCLUSIONS
Pep-1 has antichlamydial activity by preventing intracellular chlamydial growth and replication but has no effect on extracellular chlamydiae.
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