Association of host cell glutathione metabolism with Chlamydia pneumoniae infection phenotype

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Lead discovery strategies for identification of Chlamydia pneumoniae inhibitors

Throughout its known history, the gram-negative bacterium Chlamydia pneumoniae has remained a challenging target for antibacterial chemotherapy and drug discovery. Owing to its well-known propensity for persistence and recent reports on antimicrobial resistence within closely related species, new approaches for targeting this ubiquitous human pathogen are urgently needed. In this review, we describe the strategies that have been successfully applied for the identification of nonconventional antichlamydial agents, including target-based and ligand-based virtual screening, ethnopharmacological approach and pharmacophore-based design of antimicrobial peptide-mimicking compounds. Among the antichlamydial agents identified via these strategies, most translational work has been carried out with plant phenolics. Thus, currently available data on their properties as antichlamydial agents are described, highlighting their potential mechanisms of action. In this context, the role of mitogen-activated protein kinase activation in the intracellular growth and survival of C. pneumoniae is discussed. Owing to the complex and often complementary pathways applied by C. pneumoniae in the different stages of its life cycle, multitargeted therapy approaches are expected to provide better tools for antichlamydial therapy than agents with a single molecular target.Peer reviewe

Recent advances in technologies for developing drugs against Chlamydia pneumoniae

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Case processing in supporting the development of expertise in pharmacy - an eye movement study

The purpose of this study is to utilize process-level analyses to investigate pharmacy students’ reasoning during solving a written case task that handled acute patient counseling situation in the pharmacy. Participants’ (N = 34) problem-solving processes were investigated using the eye-tracking method together with written tasks and 2nd (n = 16) and 3rd (n = 18) –year students’ processes were compared. The text included semantically different level sentences: task-relevant sentences including essential information for the solution and task-redundant sentences that contained irrelevant or misleading information. The results showed that students differed in their performance and only four 2nd year students solved the case correctly, whereas almost all of the graduating students were successful. Further, most of those students, who ended up with a correct solution had presented a correct working hypothesis already after reading the first text page. Generally, the average total reading times did not differ between the comparison groups. However, better-succeeding students read significantly longer the very first task-relevant sentences of the case task indicating that they were able to focus on relevant information and discard the task-redundant text parts. Based on the results, pedagogical suggestions for advancing higher education are discussed.Peer reviewe

First-year pharmacy students' prior knowledge correlates with study progress and reveals different dynamics of misconceptions

The varying levels and quality of students’ prior knowledge pose a challenge for instruction at university. Due to the scarcity of studies in pharmacy, in this study pharmacy students (N=126) prior knowledge of biosciences was measured at the beginning of their first study year using a questionnaire comprising ten multiple choice questions and a case task. The results of multiple-choice and open-ended questions revealed serious gaps and different-level misconceptions in students’ answers partly related to the absence of elementary knowledge. The level of prior knowledge correlated with study progress measured at the end of the first study year. The study’s findings suggest that it is possible to identify students at risk of delayed studies using this kind of relatively light pre-test. Problem-solving tasks such as case descriptions can be used to detect potential misconceptions. The pedagogical implications of these results are discussed.Peer reviewe

A platform for studying the transfer of Chlamydia pneumoniae infection between respiratory epithelium and phagocytes

The obligate intracellular bacterium, Chlamydia pneumoniae, has been identified as a risk factor for several chronic inflammatory diseases in addition to respiratory tract infections. The dissemination of C. pneumoniae from respiratory tract to secondary sites of infection occurs via infected monocyte / macrophage line cells, in which C. pneumoniae can persist as an antibiotic-refractory phenotype. To allow more detailed studies on the epithelium-monocyte/macrophage transition of the infection, new in vitro bioassays are needed. To this end, a coculture system with human continuous cell lines was established. Respiratory epithelial HL cells were infected with C. pneumoniae and THP-1 monocytes were added into the cultures at 67 h post infection. After a 5 h coculture, THP-1 cells were collected with a biotinylated HLA antibody and streptavidin-coated magnetic beads and C. pneumoniae genome copy numbers in THP-1 determined by quantitative PCR. The assay was optimized for cell densities, incubation time, THP-1 separation technique and buffer composition, and its robustness was demonstrated by a Z' value of 0.6. The mitogen-activated protein kinase (MAPK) inhibitors: SP600125 (JNK inhibitor), SB203580 (p38 inhibitor) and FR180204 (ERK inhibitor) suppressed the transfer of C. pneumoniae from HL to THP-1 cells, making them suitable positive controls for the assay. Based on analysis of separate steps of the process, the MAPK inhibitors suppress the bacterial entry to THP-1 cells. The transfer of C. pneumoniae from epithelium to phagocytes represents a crucial step in the establishment of persistent infections by this pathogen, and the presented methods enables future studies to block this process by therapeutic means.Peer reviewe

A ProteomicS study on Chlamydia pneumoniae -Induced Changes in Macrophages

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Assaying Chlamydia pneumoniae Persistence in Monocyte-Derived Macrophages Identifies Dibenzocyclooctadiene Lignans as Phenotypic Switchers

Antibiotic-tolerant persister bacteria involve frequent treatment failures, relapsing infections and the need for extended antibiotic treatment. The virulence of an intracellular human pathogen C. pneumoniae is tightly linked to its propensity for persistence and means for its chemosensitization are urgently needed. In the current work, persistence of C. pneumoniae clinical isolate CV6 was studied in THP-1 macrophages using quantitative PCR and quantitative culture. A dibenzocyclooctadiene lignan schisandrin reverted C. pneumoniae persistence and promoted productive infection. The concomitant administration of schisandrin and azithromycin resulted in significantly improved bacterial eradication compared to sole azithromycin treatment. In addition, the closely related lignan schisandrin C was superior to azithromycin in eradicating the C. pneumoniae infection from the macrophages. The observed chemosensitization of C. pneumoniae was associated with the suppression of cellular glutathione pools by the lignans, implying to a previously unknown aspect of chlamydia–host interactions. These data indicate that schisandrin lignans induce a phenotypic switch in C. pneumoniae, promoting the productive and antibiotic-susceptible phenotype instead of persistence. By this means, these medicinal plant -derived compounds show potential as adjuvant therapies for intracellular bacteria resuscitation

Impact of dibenzocyclooctadiene lignans from Schisandra chinensis on the redox status and activation of human innate immune system cells

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