The Small Molecule H89 Inhibits Chlamydia Inclusion Growth and Production of Infectious Progeny

Abstract

Chlamydia is an obligate intracellular bacterium and the most common reportable cause of human infection in the U.S. This pathogen proliferates inside a eukaryotic host cell, where it resides within a membrane-bound compartment called the chlamydial inclusion. It has an unusual developmental cycle, marked by conversion between a replicating form, the reticulate body (RB), and an infectious form, the elementary body (EB). We found that the small molecule H89 slowed inclusion growth and decreased overall RB replication by 2-fold, but caused a 25-fold reduction in infectious EBs. This disproportionate effect on EB production was mainly due to a defect in RB-to-EB conversion and not to the induction of chlamydial persistence, which is an altered growth state. Although H89 is a known inhibitor of specific protein kinases and vesicular transport to and from the Golgi, it did not cause these anti-chlamydial effects by blocking the protein kinases PKA or PKC, or by inhibiting protein or lipid transport. H89 is thus a novel anti-chlamydial compound that has a unique combination of effects on the intracellular Chlamydia infection.

Differential Effects of Small Molecule Inhibitors on the Intracellular Chlamydia Infection

“…6 ). For example, MK2206 and BFA each caused an about 10-fold decrease in progeny, while KSK120 and another published chlamydial inhibitor, H89, reduced progeny by 83- and 35-fold, respectively ( 17 ). These effects were much more severe than what we observed for Compound C, which produced a modest 3-fold reduction in progeny, in the same range as the CPAF mutant, RST17 ( Fig.…”

Chlamydia trachomatis induces disassembly of the primary cilium to promote the intracellular infection

“…Progeny assays were performed as previously described [ 46 ]. hTERT-RPE-1 WT or GFP-SMO Cep290 WT/KO cells treated with inhibitors or siRNAs were infected with Chlamydia for 30 hours at an MOI of 3.…”

A Reverse Genetic Approach for Studying sRNAs in Chlamydia trachomatis

“…Progeny assays were performed as previously described ( 49 ). In brief, at the indicated times, Chlamydia - infected cells were washed with 1×PBS and collected in SPG to harvest infectious EBs from the primary infection.…”