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Browsing by Subject "macrophage"

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  • Taavitsainen, Eveliina (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.
  • Snellman, Nana (2023)
    Chlamydia pneumoniae is an intracellular Gram-negative bacterium, that can cause respiratory infections. Infections are typically mild or asymptomatic, but it can also lead to more severe infections, for example, pneumonia. Severe infections might need antibiotic treatment. When the bacteria are exposed to stressful conditions, they can change to a chronic, persistent form. Amoxicillin and penicillin are known to transform bacterium into persistent forms. Antibiotics are not effective for persistent infection very often. Amoxicillin is the recommended treatment for pneumonia in Finland and worldwide, which is problematic from the perspective of C. pneumoniae. That is why there is a need for effective treatment for persistent C. pneumoniae infection. Probiotics and their by-products short chain fatty acids (SCFAs) are known to have beneficial effects on human health. Based on the current knowledge, SCFAs and other probiotic by-products are known to inhibit pathogen bacterial growth. Thus, SCFAs could have a potential effect on the treatment of C. pneumoniae infection. The aim of this work is to study the impact of SCFAs, acetate, propionate, and butyrate on C. pneumoniae infection and its antibiotic susceptibility. To study the impact of acetate, propionate and butyrate on C. pneumoniae infection and its antibiotic susceptibility, three different infection models were used: productive C. pneumoniae infection model with A549 cells, amoxicillin-induced persistent infection model with A549 cells, and persistent infection model with THP1 cells. Bacterial growth was followed with immunofluorescence and the number of the bacterial genome was studied with quantitative polymerase chain reaction (qPCR). The studied SCFAs did not have a significant impact on productive C. pneumoniae infection. With amoxicillin- induced persistent infection, the results were varying. For example, sodium acetate, and propionate showed some increase in bacterial growth on the first infection, but with sodium butyrate, there were not any impact. The only SCFA that decreased the bacterial growth in the persistent infection model with THP1 cells was sodium butyrate (200 μM). The same treatment also decreased the number of bacterial genomes with qPCR in the same infection model. In addition, the same condition increased the antibiotic susceptibility of persistent C. pneumoniae to azithromycin in THP1 cells. In conclusion, the studied SCFAs seemed to have more impact on C. pneumoniae infection with human immune cells compared to human lung epithelial cells. Based on this study, sodium butyrate could have positive impacts against persistent C. pneumoniae infection. Nevertheless, further studies of the impact of sodium butyrate on persistent C. pneumoniae infection are needed.