Browsing by Subject "anti-chlamydial compounds"

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  • Lohtaja, Milka (Helsingfors universitet, 2016)
    Chlamydia pneumoniae is an intracellular bacterium that causes a variety of respiratory infections to humans such as pneumonia and bronchitis. In addition C. pneumoniae -infection has been associated with multiple chronic diseases of which the most important are atherosclerosis and vascular diseases, asthma, chronic obstructive pulmonary disease and different kinds of neurological disorders. C. pneumoniae is a very common pathogen that has the ability to hide in the system in a persistent chronic form out of reach of the immune defences. C. pneumoniae has been shown to infect many other cell types besides bronchial epithelial cells. These cells include monocytes, macrophages and vascular endothelial cells. C. pneumoniae induces the secretion of different kinds of cytokines and cell signalling molecules and the expression of adhesion molecules in all of these cell types. Too strong cytokine and immune response is detrimental to cells and to whole system. Currently available antibiotics aren't effective enough against C. pneumoniae -infection, especially against its chronic form. Furthermore, the lack of effective anti-chlamydial drugs impairs the research of the association between C. pneumoniae and chronic diseases. The aim of this study was to investigate the effect of anti-chlamydial compounds on the release of cytokines and cell signaling molecule, nitric oxide, induced by C. pneumoniae -infection in different cell types. These anti-chlamydial compounds are currently under the investigation in the faculty of pharmacy. In addition the anti-inflammatory properties of the compounds were further investigated with the help of lipopolysaccharide of another gram-negative bacterium E. coli. The groups of compounds investigated in this study were β2,2-amino acid derivatives, Schisandra chinensis -lignans, TE-compounds synthesized in Vienna and benzimidazole compounds synthesized in the faculty of pharmacy. There were four cell types used in this study, HL- and BEAS-2B-epithelial cells, THP-1-monocytes/macrophages and RAW264.7-macrophages. The study focused on the determination of vascular endothelial growth factor VEGF and interleukins IL-8, IL-10 and IL-12. The concentrations of cytokines in the cell medium were measured after infection using ELISA-method. Nitric oxide measurements were also determined from the medium using Griess' reagent. Immunofluorescence labeling was used to confirm the infection and the infection was verified by fluorescence microscope. In addition some of the compounds were tested for the cell viability using resazurin assay. All the groups of compounds showed desired effects on the release of cytokines and nitric oxide. Especially β2,2-amino acid derivatives reduced clearly the release of both cytokines and nitric oxide. β2,2-amino acid derivatives could thus be potential drug candidates for the development of anti-chlamydial and anti-inflammatory drugs. Schisandra chinensis -lignans inhibited especially the release of nitric oxide in both C. pneumoniae -infected and LPS-stimulated cells which may tell about their broad anti-inflammatory properties. There were also found desired results with TE-compounds and benzimidazole compounds. Interleukins were not secreted by any of the studied cells so that part needs more research and further investigation. Based on the results found in this study it can be concluded that the studied compounds could be potential lead compounds in the discovery of anti-chlamydial drugs and drugs that specifically inhibit C. pneumoniae -infection. Further research is needed concerning the effects of these compounds on cytokines and especially on chronic infection.
  • Taavitsainen, Eveliina (Helsingfors universitet, 2017)
    Chlamydia pneumoniae is an intracellular human pathogen that causes respiratory infections such as pneumonia. Antibodies have been found in serological samples worldwide and most likely every person gets an infection at least once in lifetime. In particular, persistent C.pneumoniae-infection has been associated with multiple chronic diseases such as atherosclerosis, asthma and neurological diseases. C.pneumoniae has a unique two-stage life cycle with two morphological forms; elementary body and reticulate body. In addition, the bacterium has a chronic persistent form. Persistent infection is very typical. Persistent infection can be produced in many ways in vitro, but it has been also found that C.pneumoniae is spontaneously transformed into persistent form in macrophages and monocytes. The aim of this study was to investigate the effect of anti-chlamydial compounds previously identified in the research group on the persistent infektion of C.pneumoniae. For the study, the growth of the bacteria was monitored by qPCR in different cell lines and the compatibility of the compounds with the used persistence model was studied. Four different cell lines were used in the study; HL epithelial cells, Raw264.7 macrophages, THP1 monocytes and macrophages. The effect of compounds on the used cell line was first examined by viability assays. For further studies, C.pneumoniae growth was studied in different cell lines. An qPCR method was set up and used to monitor C.pneumoniae genome copy numbers in infected samples. Based on the growth curves, the measurement points were determined for further studies. Finally, the effect of suitable compounds on C.pneumoniae infection was investigated in epithelial, monocyte and macrophage cell lines. From the investigated compounds, Schisandra chinensis-lingnans were selected for further studies with Raw264.7 cells. The genome number wa not found to decrease compared to the after schisandrin or schisandrin B treatment. In the experiment of the growth of the bacterium, schisandrin-treated samples showed that the genome number of bacterium would be re-grown. This may potentially mean the persistent infection change back to the active form, whereby the bacterium resumed proliferate in the host cell. Based on the results of this study, schisandrin may be considered a potential compound for further studies and a possible model compound for the development of compound against C.pneumoniae infection. However, further studies on the effect of the compounds on persistent infection are needed.