Chlamydial organisms are strict intracellular parasites, whose requirements in the metabolites are covered

by the host cells. Enhanced uptake of the substrates and metabolites by the infected host cells is a well known “”signature”" strategy of chlamydial infection mandatory for successful accomplishment of its infectious cycle [25]. However, in the case of the chlamydial growth in HepG2 cells we have seen significant decline in LDL-receptor mRNA, which may potentially result in the reduction of lipid uptake. The biological significance of this finding remains unclear. However it is possible to assume, that decline in the LDL-receptor mRNA might represent a mechanism of metabolic adaption of the host cell to chlamydial

infection targeted on limitation of lipid supply and chlamydial growth in the cells. Unfortunately we VX-689 purchase were not able to document corresponding changes in LDL-receptor protein level due to decline in number of viable HepG2 cells that occurs at 72 hour time point of post-infection period. Models of persistent chlamydial infection might CA-4948 purchase be required for evaluating hepatic LDL-receptor turnover in the infected liver cells. Secondly, we have clearly shown that mevastatin, an inhibitor of cholesterol biosynthesis, restores LDL-receptor mRNA and has a significant anti-chlamydial activity reducing chlamydial growth in infected hepatocytes. Genome of C. trachomatis does not contain genes responsible for lipid biosynthesis. Chlamydial species are known to acquire cholesterol, fatty acids and triglycerides from the host cells [26]. Therefore, it was reasonable to

believe that targeting Sitaxentan the cholesterol biosynthetic pathway in the host cells might affect chlamydial infection rate. This prediction was confirmed by RT PCR analysis. It is well acknowledged, that C. trachomatis 16S rRNA gene expression is an informative criterion of chlamydial developmental cycle expressed in both early and late stages of C. trachomatis infection [27]. Detection of 16S rRNA transcript as a marker of viable and metabolically active Chlamydia allows to evaluate the effectiveness of different antibacterial agents [28]. Maximum inhibition of 16S rRNA as well as drastic reduction in the number of infected immunofluorescence-positive cell has been seen at 40 μM mevastatin level. Less pronounced decline in 16S rRNA transcript level has been observed at 20 μM mevastatin concentration. Even though addition of 20 μM mevastatin did not result in Tideglusib in vivo complete inhibition of chlamydial growth in HepG2 cells, there was formation of smaller chlamydial inclusions. Those are often observed in antibiotic- and/or cytokine-treated cells when concentration of the agent is not enough to induce complete eradication of the pathogen [23]. “”Aberrant”" chlamydial cells are known to have some metabolic activity but fail to induce new rounds of chlamydial infection [23, 28].