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:Here, we challenged rabbits with repeated feeding of Ixodes ricinus adults and observed the formation of specific antibodies against several tick salivary proteins. To identify the salivary antigens, isolated immunoglobulins from repeatedly infested rabbits were utilised for a pull-down from the saliva of pilocarpine-treated ticks. Eluted antigens were separated on 1D SDS-PAGE and analysed by peptide mass fingerprinting. To increase the authenticity of immunogens identified, we also performed, for the first time, de novo assembly of the sialome from I. ricinus females fed for six days, a timepoint used for pilocarpine-salivation.
Project description:We report differential gene expression with tissue-specific signatures in tick cell lines infected with Anaplasma phagocytophilum - transcriptional response to infection of I. scapularis ISE6 cells resembled that of tick hemocytes while the response in I. ricinus IRE/CTVM20 cells resembles that of tick midguts.
Project description:The midgut of the tick is the most important tissue for the storage and digestion of host blood, which serves as the sole source of energy and nutrients for all tick development and reproduction. During feeding at each developmental stage, dynamic changes in the tick midgut epithelium reflect changes in physiological processes in this tissue. In addition, the midgut serves as the primary interface between the tick and tick-borne pathogens, which determines the vector competence of the tick. Several transcriptome data from Ixodes ricinus have been published, but few studies have examined tick proteomes. In contrast to transcriptome data, proteomics provides a deeper understanding of key cellular processes occurring in the investigated tissues. In this work, we present for the first time insight into proteomics of the midgut of I. ricinus nymph. Label-free quantitative proteomics was used to elucidate changes during blood meal and development in I. ricinus. A total of 1 534 I. ricinus-specific proteins were identified, with only a few host proteins detected. In addition, the proteins involved in the specific physiological processes of the tick were studied in detail to gain better insight into the ontogeny of the midgut of the nymph.
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.