Project description:Ticks are blood feeding arthropod ectoparasites that transmit pathogens, which cause diseases in humans and animals worldwide. In the past ten decades, the continuous human exploitation of environmental resources and the increase in human outdoor activities has promoted contact with arthropod vectors normally present in the wild, resulting in increased transmission of vector-borne pathogens. In addition, vector populations are expanding in response to climate change and human interventions that impact reservoir host movement and human exposure to infected vectors. Among these emerging vector-borne pathogens, Anaplasma phagocytophilum (Rickettsiales: Anaplasmataceae) has become an important tick-borne pathogen in the United States, Europe and Asia, with increasing numbers of infected people and animals every year. Diseases caused by A. phagocytophilum include human granulocytic anaplasmosis (HGA), equine and canine granulocytic anaplasmosis and tick-borne fever (TBF) in ruminants. The natural infection cycle of A. phagocytophilum is dependent upon the presence of infected vertebrate reservoir hosts and Ixodid tick vectors. In the United States and Europe the main vector species are Ixodes scapularis, Ixodes pacificus, and Ixodes ricinus, while a wide range of mammals, lizards, and birds serve as reservoir hosts for various A. phagocytophilum genotypes. A. phagocytophilum initially infects tick midgut cells and then subsequently develops in salivary glands for transmission to susceptible hosts during tick feeding where the pathogen infects granulocytic cells, primarily neutrophils. Anaplasma phagocytophilum develops within membrane-bound inclusions in the host cell cytoplasm. This pathogen has evolved with its tick and vertebrate hosts through dynamic processes involving genetic traits of the pathogen and hosts that collectively mediate pathogen infection, development, persistence, and survival. However, the mechanisms used by A. phagocytophilum for molecular mechanisms involved in tick-pathogen interactions have not been fully characterized. The objective of this study is to characterize the dynamics of the microRNA response in the tick vector Ixodes scapularis in response to A. phagocytophilum infection. To address this objective, the composition of tick microRNAs was characterize using RNA sequencing in I. scapularis tick cells in response to A. phagocytophilum infection. The discovery of these mechanisms provides evidence that a control strategy could be developed targeted at both vertebrate and tick hosts for more complete control of A. phagocytophilum and its associated diseases.
Project description:There has been an emergence and expansion of tick-borne diseases in Europe, Asia and North America in recent years, including Lyme disease, tick-borne encephalitis, and human anaplasmosis. The primary tick vectors implicated are hard ticks of the Ixodes genera. Although much is known about the host response to these bacterial and viral pathogens, there is limited knowledge of the cellular responses to infection within the tick vector. The bacterium Anaplasma phagocytophilum (A. phagocytophilum), is able to bypass apoptotic processes in ticks, enabling infection to proceed. However, the tick cellular responses to infection with the flaviviruses tick-borne encephalitis virus (TBEV) and louping ill virus (LIV), which cause tick-borne encephalitis and louping ill respectively, are less clear. Infection of an Ixodes ricinus (I. ricinus) tick cell line with the viruses LIV and TBEV, and the bacterium A. phagocytophilum, identified activation of common and distinct cellular pathways. In particular, commonly-upregulated genes included those that modulate apoptotic pathways (HSP70), putative anti-pathogen genes (FKBP and XBL1), and genes that influence the tick innate immune response, including selective activation of toll genes. These data provide an insight into potentially key genes involved in the tick cellular response to viral or bacterial infection.
Project description:Previously, we observed that a tick salivary protein named sialostatin L2 (SL2) mitigates caspase 1-mediated inflammation upon Anaplasma phagocytophilum infection. Here we are performing next-generation sequencing to determine the global effect of SL2 upon A. phagocytophilum infection of macrophages. BMDMs were treated by 4 different conditions (including non-treated, treated by SL2, treated by Anaplasma, and by Anaplasma and SL2, each treatment was performed in triplicate) followed by the extraction of total RNA and deep sequencing by Illumina
Project description:Previously, we observed that a tick salivary protein named sialostatin L2 (SL2) mitigates caspase 1-mediated inflammation upon Anaplasma phagocytophilum infection. Here we are performing next-generation sequencing to determine the global effect of SL2 upon A. phagocytophilum infection of macrophages.
Project description:Anaplasma phagocytophilum is the causative agent of tick-borne fever (TBF) in ruminants and human, equine and canine granulocytic anaplasmosis. A. phagocytophilum modifies host gene expression and immune response. The objective of this work was to analyze differential gene expression in A. phagocytophilum-infected sheep using microarray hybridization and real-time RT-PCR in experimentally and naturally infected animals. Keywords: disease state analysis
Project description:Anaplasma phagocytophilum infects a wide variety of host species and causes the diseases granulocytic anaplasmosis in humans, horses and dogs and tick-borne fever in ruminants. The objective of this research was to characterize differential gene expression in wild boar naturally infected with A. phagocytophilum by microarray hybridization using the GeneChip® Porcine Genome Array
Project description:Background: Anaplasma phagocytophilum is an obligate intracellular prokaryotic pathogen that both infects and replicates within human neutrophils. The bacterium represses multiple antimicrobial functions while simultaneously increasing proinflammatory functions by reprogramming the neutrophil genome. Previous reports show that many observed phenotypic changes are in part explained by altered gene transcription. We recently identified that large chromosomal regions of the neutrophil genome are differentially expressed during A. phagocytophilum infection. Because of this, we sought to determine whether gene expression programs altered by infection were the result of changes in the host neutrophil DNA methylome. Results: Within 24 h of infection, marked increases in DNA methylation were observed genome-wide as compared with mock-infected controls and pharmacologic inhibition of DNA methyltransferases resulted in decreased bacterial growth. New regions of DNA methylation were enriched at intron and exon junctions; however, intragenic methylation did not correlate with altered gene expression. In contrast, intergenic DNA methylation was associated with A. phagocytophilum-induced gene expression changes. Within the major histocompatibility complex locus on chromosome 6, a region with marked changes in infection-induced differential gene expression, new regions of methylation were localized to boundaries of active and inactive chromatin. Conclusions: These data strongly suggest that A. phagocytophilum infection, in addition to altering histone structure, alters DNA methylation and the epigenome of its host cell to promote survival and replication, providing evidence that such bacterial infection can radically alter the epigenome of its host cell. Examination of methylated DNA sites in 3 human donors' neutrophils with and without 24h infection by Anaplasma phagocytophilum.
Project description:Gene expression profiling of human promyelocytic cells in response to infection with Anaplasma phagocytophilum. Total RNA derived from 3DPI Anaplasma phagocytophilum-infected HL-60 cells was labeled with A647 and total RNA derived from 3DPI Mock-infected HL-60 cells was labeled with A546. For each, 5 µg of total RNA was labeled using Genisphere Array900, Alexa Fluor dyes and SuperscriptII. Slide scanned with ScanArray Express and images processed with GenePix Pro version 4.0. Normalized log ratios VALUES determined using R-project statistical environment (http://www.r-project.org) and Bioconductor (http://www.bioconductor.org) through the GenePix AutoProcessor (GPAP, http://darwin.biochem.okstate.edu/gpap) website (P. Ayoubi, unpublished results). Keywords: time-course