Project description:Ticks are vectors of different pathogens causing human and animal diseases. Particularly, Rickettsia slovaca is zoonotic infectious bacterium transmitted by Dermacentor ticks, agent of tick-borne lymphadenopathy (TIBOLA), common across Europe. Current studies point to extreme complexity of bacterial induced effects in tick host. Systems biology tools, including proteomics, greatly contribute to understanding of molecular details of pathogen-tick-host interactions. Herein we compared laboratory-infected ticks with uninfected control after four weeks of incubation. Propagation of R. slovaca was confirmed by quantitative PCR. Using DNA was confirmed infection with R. slovaca. By proteomic approach, we discovered 33 differentially abundant gel spots, 23 of them accumulated upon artificial infection with R. slovaca. Modest 6.9% of tick proteome was affected. The protein localizations showing that eight proteins spots might be secreted, three cytoplasmic, two mitochondrial, six likely having multiple localizations, one cell membrane and one nucleus. We identified following proteins defensin, serpins, glycine-rich protein, heat shock protein involved in artificially infected tick vector, Dermacentor reticulatus. Discovered differentially abundant proteins should be further evaluated as targets to block the transmission of bacterial pathogen.
Project description:The Ixodidea tick Dermacentor marginatus is a vector of many pathogens wide spread in Eurasia. Study of gene targets of the tick species provides insight to find novel tick protective antigen for drug development and vaccine targets. To obtain a broader picture of gene sequences and changes in expression level, we aimed to characterize the whole body transcriptome in D. marginatus adult female after engorgement and long-term starvation using RNA-seq. We have assembled and analyzed transcriptome of D. marginatus females 5 days after ecdysis, 24 h after a blood meal, and 6 months under controlled experimental conditions. Sequencing produced 30251 unigenes, of which 32% were annotated using Trinity. Gene expression was compared among groups differed by status as newly molted, starved and engorged female adult ticks. Nearly 1/3 of the unigenes in each group were differentially expressed compared to the other two group, and we found that the most numerous were proteins involved in catalytic and binding activities and apoptosis. Selected up-regulated differentially expressed genes in each group associated to protein, lipids, carbohydrate and chitin metabolism. Blood feeding and long-term starvation also caused genes differentially expressed in the defense response and antioxidant response. Finding the sequence information and expression pattern would be helpful in understanding molecular physiology of D. marginatus, and provides information for anti-tick vaccine and drug development.
Project description:Background Human monocytotropic ehrlichiosis is an emerging life-threatening zoonosis caused by obligately intracellular bacterium, Ehrlichia chaffeensis. E. chaffeensis is transmitted by the lone star tick, Amblyomma americanum, and replicates in mononuclear phagocytes in mammalian hosts. Differences in the E. chaffeensis transcriptome in mammalian and arthropod hosts are unknown. Thus, we determined host-specific E. chaffeensis gene expression in human monocyte (THP-1) and in Amblyomma and Ixodes tick cell lines (AAE2 and ISE6) using a whole genome microarray. Methodology/Principal Findings The majority (~80%) of E. chaffeensis genes were expressed during infection in human and tick cells. There were few differences observed in E. chaffeensis gene expression between the vector Amblyomma and non-vector Ixodes tick cells, but extensive host-specific and differential gene expression profiles were detected between human and tick cells, including higher transcriptional activity in tick cells and identification of gene subsets that were differentially expressed in the two hosts. Differentially and host-specifically expressed ehrlichial genes encoded major immunoreactive tandem repeat proteins (TRP), the outer membrane protein (OMP-1) family, and hypothetical proteins that were 30–80 amino acids in length. Consistent with previous observations, high expression of p28 and OMP-1B genes was detected in human and tick cells, respectively. Notably, E. chaffeensis genes encoding TRP32 and TRP47 were highly upregulated in the human monocytes and expressed as proteins; however, although TRP transcripts were expressed in tick cells, the proteins were not detected in whole cell lysates demonstrating that TRP expression was post transcriptionally regulated. Conclusions/Significance Ehrlichia gene expression is highly active in tick cells, and differential gene expression among a wide variety of host-pathogen associated genes occurs. Furthermore, we demonstrate that genes associated with host-pathogen interactions are differentially expressed and regulated by post transcriptional mechanisms. A microarray (4-plex) study using E. chaffeensis cultivated in each cell line (THP-1, AAE2 and ISE6), three biological replicates/cell line. For each cell line, RNA was also extracted from uninfected cells (negative controls) and was processed similar to the infected cells; these samples were used for background subtraction during data analysis.
Project description:Background Human monocytotropic ehrlichiosis is an emerging life-threatening zoonosis caused by obligately intracellular bacterium, Ehrlichia chaffeensis. E. chaffeensis is transmitted by the lone star tick, Amblyomma americanum, and replicates in mononuclear phagocytes in mammalian hosts. Differences in the E. chaffeensis transcriptome in mammalian and arthropod hosts are unknown. Thus, we determined host-specific E. chaffeensis gene expression in human monocyte (THP-1) and in Amblyomma and Ixodes tick cell lines (AAE2 and ISE6) using a whole genome microarray. Methodology/Principal Findings The majority (~80%) of E. chaffeensis genes were expressed during infection in human and tick cells. There were few differences observed in E. chaffeensis gene expression between the vector Amblyomma and non-vector Ixodes tick cells, but extensive host-specific and differential gene expression profiles were detected between human and tick cells, including higher transcriptional activity in tick cells and identification of gene subsets that were differentially expressed in the two hosts. Differentially and host-specifically expressed ehrlichial genes encoded major immunoreactive tandem repeat proteins (TRP), the outer membrane protein (OMP-1) family, and hypothetical proteins that were 30–80 amino acids in length. Consistent with previous observations, high expression of p28 and OMP-1B genes was detected in human and tick cells, respectively. Notably, E. chaffeensis genes encoding TRP32 and TRP47 were highly upregulated in the human monocytes and expressed as proteins; however, although TRP transcripts were expressed in tick cells, the proteins were not detected in whole cell lysates demonstrating that TRP expression was post transcriptionally regulated. Conclusions/Significance Ehrlichia gene expression is highly active in tick cells, and differential gene expression among a wide variety of host-pathogen associated genes occurs. Furthermore, we demonstrate that genes associated with host-pathogen interactions are differentially expressed and regulated by post transcriptional mechanisms.