Browsing by Subject "Infection course"

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Transcriptomic analyses during infectious anemia in pigs
(2019) Mack, Sarah-Lena; Hölzle, Ludwig
Mycoplasma suis (M. suis) is a uncultivable hemotrophic bactreia parasiting red blood cells in pigs and a small range of other animals. It becomes more and more important because of leading to big economic losses in swine industry. M. suis causes anemia in pigs and is accompanied with other immunosuppressive diseases. A once infected animals is a life-long carrier and could infect other animals as well. To date, there is less information about the pathogenesis and reproduction of the bacteria and it is not possible to cultivate M. suis in vitro. One objective of the present study was to get more information about the transcriptomic changes in a pig during an infection course. Therefore, 3 splenectomized piglets were infected with the highly virulent strain KI_3806. After 2, 4 and 8 days post infection (p.i.) blood samples were taken and total RNA of blood was extracted. Microarray analyses were performed with a commercial Affymetrix array. Using microarrays more than 7000 DE genes from infected pigs could be detected. With M. suis in its host cells – the erythrocyte – we had a perfect model showing molecular interactions or signaling pathways in the M. suis infection process. With the help of the Ingenuity pathway analyses service many genes involved in immune and inflammatory response were found. Moreover typical genes involved in anemia, psoriasis and endothelial cell damage could be observed. The detection of these genes verified the depression and alteration of the immune system by M. suis resulting in evading the immune system and therefore in persisting among the organism. Another aim was to go deeper on the transcriptional level of M. suis and to get insights of the behavior of the bacteria at the time point of and after infection. RNA Sequencing was performed on a HiSeq 2000 Genome Analyzer from Illumina an resulting reads were mapped to reference sequences M. suis KI_3806 and Sus scrofa. Moreover, differential expression analysis was performed using the edgeR package. After mapping, it could be observed that on day 4 p.i. M. suis transcripts seem to be overlapped by porcine transcripts, whereas on day 8 p.i. most of the reads could be allocated to the M. suis genome resulting in almost all M. suis genes were found to be transcribed at the end of infection. When looking at the COG categories the group of proteins with “unknown function” (hypothetical proteins) represented the largest group on both days. Also a high number within the differentially expressed genes were hypothetical genes showing that these genes play an important role during infection. Further investigations are needed to confirm that the hypothetical genes also are involved in M. suis replication and recombination. In conclusion, our analysis revealed several thousand genes differentially expressed during acute IAP and numerous altered pathways and cellular processes throughout the course of host response to acute M. suis infections, thus contributing to a better understanding of the IAP pathogenesis. Moreover, this could lead to new approaches towards cultivation of M. suis as well as therapeutic treatments.