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:Tick-borne diseases (TBDs) are the most common illnesses transmitted by ticks, and the annual number of reported TBD cases continues to increase. The Asian longhorned tick, a vector associated with at least 30 human pathogens, is native to eastern Asia and recently reached the USA as an emerging disease threat. Newly identified tick-transmitted pathogens continue to be reported, raising concerns about how TBDs occur. Interestingly, tick can harbor pathogens without being affected themselves. For viral infections, ticks have their own immune systems that protect them from infection. Meanwhile, tick-borne viruses have evolved to avoid these defenses as they establish themselves within the vector. Here, we show in detail that infecting longhorned ticks with distinct arthropod-borne RNA viruses through two approaches natural blood feeding and injection, all induce the production of vsiRNAs. Dicer2-like homolog plays a role in regulating antiviral RNAi responses as knocking down of this gene enhanced viral replication. Furthermore, we demonstrate that tick antiviral RNAi responses are inhibited through expression heterologous VSR proteins in recombinant SINV. We identify both the virus and tick factors are critical components to understanding TBDs. Importantly, our study introduces a novel, in vivo virus-vector-mouse model system for exploring TBDs in the future.
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:Lyme borreliosis (LB) is a tick-borne infection caused by Borrelia burgdorferi. Dogs are at high risk of exposure to ticks and tick-borne pathogens, including B. burgdorferi. Immunodiagnostic assays are usually based on whole-cell preparations of B. burgdorferi as substrate and, consequently, interpretation of results is confounded by antibody cross-reactivity between borrelial antigens and other bacterial species, as well as the anti-LB vaccination status of the dog. For this study, we examined sera from 33 dogs that were experimentally infected with B. burgdorferi through tick bite. These sera were compared with sera from uninfected dogs in their reactivities to 72 different recombinant B. burgdorferi antigens and 24 OspC protein types on a protein microarray. Amongst antigens frequently recognized by infected dogs were several known to be immunogens for humans, such as Decorin-binding protein A (BBA25), BBA64, fibronectin-binding protein (BBK32), VlsE, Erp and Bdr, CRASP proteins, OspC proteins and some flagellar antigens. Of special interest were the novel antigens BBB14 and BB0844, both hypothetical lipoproteins about which very little is currently known, and that were frequently and strongly recognized by infected dog sera. The antibody response of B. burgdorferi-infected dogs presents both similarities and differences from human counterparts, and both can be important for improvement of canine LB diagnosis and vaccine development. Antibody profiling was performed on sera from dogs experimentally-infected with B. burgdorferi and unexposed controls against antigens of B. burgdorferi. Thirty-three serum samples from experimental infections, and 5 unexposed controls were probed on a protein microarray displaying 24 OspC proteins of B. burgdorferi .
Project description:Lyme borreliosis (LB) is a tick-borne infection caused by Borrelia burgdorferi. Dogs are at high risk of exposure to ticks and tick-borne pathogens, including B. burgdorferi. Immunodiagnostic assays are usually based on whole-cell preparations of B. burgdorferi as substrate and, consequently, interpretation of results is confounded by antibody cross-reactivity between borrelial antigens and other bacterial species, as well as the anti-LB vaccination status of the dog. For this study, we examined sera from 33 dogs that were experimentally infected with B. burgdorferi through tick bite. These sera were compared with sera from uninfected dogs in their reactivities to 72 different recombinant B. burgdorferi polypeptides on a protein microarray. Amongst antigens frequently recognized by infected dogs were several known to be immunogens for humans, such as Decorin-binding protein A (BBA25), BBA64, fibronectin-binding protein (BBK32), VlsE, Erp and Bdr, CRASP proteins, OspC proteins and some flagellar antigens. Of special interest were the novel antigens BBB14 and BB0844, both hypothetical lipoproteins about which very little is currently known, and that were frequently and strongly recognized by infected dog sera. The antibody response of B. burgdorferi-infected dogs presents both similarities and differences from human counterparts, and both can be important for improvement of canine LB diagnosis and vaccine development. Antibody profiling was performed on sera from dogs experimentally-infected with B. burgdorferi and unexposed controls against antigens of B. burgdorferi. Thirty-three serum samples from experimental infections, and 6 unexposed controls were probed on a protein microarray displaying 72 unique proteins of B. burgdorferi .
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:Ixodes species ticks are competent vectors of tick-borne viruses including tick-borne encephalitis and Powassan encephalitis. Tick saliva has been shown to facilitate and enhance viral infection. This likely occurs by saliva-mediated modulation of host responses into patterns favorable for viral infection and dissemination. Because of the rapid kinetics of tick-borne viral transmission, this modulation must occur as early as tick attachment and initiation of feeding. In this study, the gene expression profile of cutaneous bite-site lesions created by uninfected ticks were analyzed at 1, 3, 6, and 12 hours after Ixodes scapularis nymphal tick attachment to discover host pathways or responses potentially important in tick-borne viral establishment.
Project description:Ixodes species ticks are competent vectors of tick-borne viruses including tick-borne encephalitis and Powassan encephalitis. Tick saliva has been shown to facilitate and enhance viral infection. This likely occurs by saliva-mediated modulation of host responses into patterns favorable for viral infection and dissemination. Because of the rapid kinetics of tick-borne viral transmission, this modulation must occur as early as tick attachment and initiation of feeding. In this study, the gene expression profile of cutaneous bite-site lesions created by uninfected ticks were analyzed at 1, 3, 6, and 12 hours after Ixodes scapularis nymphal tick attachment to discover host pathways or responses potentially important in tick-borne viral establishment. Four milimeter ear biopsies from BALB/cJ mice infested with Ixodes scapularis nymphs were assayed using Affymetrix genechip 430A 2.0 arrays at 1, 3, 6, and 12 hours after infestation during a primary exposure. 3 mice were measured at each time point. Controls were 3 similarly housed but tick-free mice.
Project description:Ticks, as obligate blood-feeding arthropod vectors of pathogenic viruses, bacteria, protozoa and helminths, are responsible for prevalent tick-borne diseases (TBDs) worldwide. This arthropod constitutes the second most common that transmit pathogens among humans, after mosquitoes, and the first vector in domestic animals. Vaccines constitute the safest and more effective approach to control tick and TBDs, but this is in constant research to identify new antigens and improve vaccines formulations. The tick antigen Subolesin is a well-known vaccine protective antigen with a highly conserved sequence at both gene and protein levels in the Ixodidae and among arthropods and vertebrates. In this study, RNAseq and proteomic analyses were carried out in wild type and Subolesin knockdown tick ISE6 cells in order to identify and characterize the functional implications of Subolesin in tick cells, demonstrating once again the importance of this antigen in vaccine development against tick and TBDs.
Project description:Tick saliva contains many bioactive molecules that are involved in attachment to the host, blood feeding and transmission of pathogens. MicroRNAs (miRNAs) are a class of short non-coding RNAs with a length of 19-24 nucleotides. They act as regulators of gene expression by binding to their target mRNA at the post-transcriptional level and control a variety of cellular functions, including regulation of growth, metabolism, and development. The detection and characterizations of miRNAs from tick saliva may help explain the molecular mechanisms involved in the interaction between ticks, pathogens, and hosts. They may also contribute to the discovery of vaccines, which can control ticks and the pathogens they transmit. An RNA library was generated from the saliva of fed adult Haemaphysalis longicornis ticks, and it contained 17.4 million clean reads of 18-30 nucleotides. Overall, 319 known miRNAs and 1 novel miRNA were found. The 10 most abundantly expressed miRNAs present in tick saliva were miR-100_2, miR-315, miR-184_1, miR-100-5p_2, miR-5307, miR-184-3p_3, Let-7-5p_6, miR-71_5, miR-1-3p_6, and miR-10-5p_2. The miR-375, one of the abundantly expressed, was subjected to Quantitative Real-Time PCR analysis (qRT-PCR) in various tick developmental stages, as well as in different tissues isolated from adult ticks. The expression of miR-375 in different tick development stages was highest in unfed nymphs and lowest in the egg stage. In the tissues of adult ticks, miR-375 was most highly expressed in the salivary gland. To investigate the possible role of miR-375, Ant-375 was used to inhibit the miR-375. Treated group (Ant-375) had a reduced number of eggs (t(10)= 2.652, P=0.0242), eggs that were partially desiccated, and reduced egg hatchability (t(10)=2.272, P=0.044) compared to Ms-Ant and the non-injected control. This is the first study to investigate the miRNAs profile in tick saliva and the role of miR-375 in H. longicornis. The identification and characterization of miRNA in tick saliva may help to reveal the molecular mechanisms of interactions among ticks, pathogens, and hosts and suggest new vaccine strategies to control tick borne diseases.