Transcriptional Analysis of 10 Selected Genes in a Model of Penicillin G Induced Persistence of Chlamydophila psittaci in HeLa Cells

Abstract

Chlamydophila psittaci is an important intracellular pathogen. Persistent infection is an important state of the host-parasite interaction in this chlamydial infection, which plays a significant role in spreading the organism within animal populations and in causing chronic chlamydiosis and serious sequelae. In this study, a C. psittaci persistent infection cell model was induced by penicillin G, and real-time quantitative PCR was used to study the transcriptional levels of 10 C. psittaci genes (dnaA, dnaK, ftsW, ftsY, grpE, rpsD, incC, omcB, CPSIT_0846, and CPSIT_0042) in acute and penicillin-G-induced persistent infection cultures. Compared with the acute cultures, the penicillin-G-treated cultures showed a reduced chlamydial inclusion size and a significantly decreased number of elementary body particles. Additionally, some enlarged aberrant reticulate body particles were present in the penicillin- G-treated cultures but not the acute ones. The expression levels of genes encoding products for cell division (FtsW, FtsY) and outer membrane protein E encoding gene (CPSIT_0042) were downregulated (p < 0.05) from 6 h post-infection onward in the persistent infection cultures. Also from 6 h post-infection, the expression levels of DnaA, DnaK, IncC, RpsD, GrpE, and CPSIT_0846 were upregulated (p < 0.05); however, the expression level of OmcB in the persistent infection was almost the same as that in the acute infection (p > 0.05). These results provide new insight regarding molecular activities that accompany persistence of C. psittaci, which may play important roles in the pathogenesis of C. psittaci infection.

Effect of female sex hormones on the developmental cycle of Chlamydia abortus compared to a penicillin-induced model of persistent infection

“…For instance, the membrane protein-encoding genes omcA , omcB and pmp17G and the histone like protein encoding gen hctA , were consistently down-regulated during the whole study, while others were up-regulated, such as dnaK and htrA , both transcribing for chlamydial stress response proteins. Together, these features suggest that penicillin blocked binary fission and RB-to-EB differentiation, is in line with observations obtained in studies with penicillin-stressed C. trachomatis [28], C. pneumoniae [29] and C. psittaci [15, 30]. This fact could have a significant impact on sheep farms since, even though penicillin is not the antimicrobial of choice against an outbreak of OEA, beta-lactams are the most frequently prescribed antibiotics to treat the main food-producing animals in Europe [31].…”

Localization and characterization of a putative cysteine desulfurase in Chlamydia psittaci

“…After the incubation for 2 hours, the medium was replaced with complete DMEM containing 10% FBS and 2 μg/ml cycloheximide (Abcam, Cambridge). The chlamydial organisms were propagated, purified, aliquoted, and stored as described previously . The infected cultures were processed at different time points after infection for immunofluorescence assays, quantitative real‐time PCR (qRT‐PCR) or Western blot as described below.…”

“…The chlamydial organisms were propagated, purified, aliquoted, and stored as described previously. 28 The infected cultures were processed at different time points after infection for immunofluorescence assays, quantitative real-time PCR (qRT-PCR) or Western blot as described below.…”

Analysis of Polymorphic Membrane Protein Expression in Cultured Cells Identifies PmpA and PmpH of Chlamydia psittaci as Candidate Factors in Pathogenesis and Immunity to Infection

“…psittaci Cal10 in SPG (0.25 M sucrose, 10 mM sodium phosphate and 5mM L-glutamic acid) at a multiplicity of infection (MOI) of 1 followed by incubation on a rocking platform for 2 h at 37°C. The unbound organisms were washed away with PBS and the bacteria were grown either under normal conditions using the above-mentioned medium, or by adding penicillin (100U ml -1 ) to the medium to induce stress-related persistence [ 41 ]. One ml SPG was added to a mock-infected dish.…”