Project description:The similarity of Lyme borreliosis to other diseases and the complex pathogenesis cause diagnostic and therapeutic difficulties. Changes at the cellular and molecular level after Borrelia sp. infection remain still poorly understood. Therefore, the present study focused on the gene expression in human dermal fibroblasts in differentiation of infection with Borrelia garinii, Borrelia afzelii and Borrelia burgdorferi sensu stricto spirochetes. For microarray analysis 10 samples were used: 3 control samples - K, 2 samples of NHDF cells infected with Borrelia garinii - G, 2 samples of NHDF cells infected with Borrelia afzelii - A and 3 samples of NHDF cells infected with Borrelia burgdorferi sensu stricto - SS.
Project description:Differential gene expression analysis was performed to assess the affects of the deletion of sRNA SR0726 on the in vitro transcriptome of Borrelia burgdorferi in order to investigate a potential regulatory role for the sRNA
Project description:Transcriptional profiling of gene expression between parental strain B31 and rrp1 mutant. Cyclic-di-GMP is a bacterial second messenger that modulates many biological processes. Although its role in bacterial pathogenesis during mammalian infection has been widely recognized, the role of c-di-GMP in pathogen's life cycle in vector hosts is less understood. The enzootic cycle of the Lyme disease pathogen Borrelia burgdorferi involves both a mammalian host and an Ixodes tick vector. The B. burgdorferi genome encodes a single copy of the diguanylate cyclase gene (rrp1), which is responsible for the production of c-di-GMP. To determine the role of c-di-GMP in the life cycle of B. burgdorferi, an Rrp1-deficient B. burgdorferi strain was generated. The rrp1 mutant remains infectious in the mammalian host, but could not survive in the tick vector. To identify the mechanisms of Rrp1 contributing to B. burgdorferi pathogenesis and gene regulation, microarray was employed to compare gene expression profiles between the parental strain B31 and the rrp1 mutant. Two-condition experiment, B31 vs. rrp1 mutant. Biological replicates: 3 B31, 3 rrp1 mutant, independently grown and harvested. One replicate (dye-swap) per array.
Project description:Background: Lyme borrelia genotypes differ in their capacity to cause disseminated disease. Gene array analysis was employed to profile the host transcriptome induced by Borrelia burgdorferi strains with different capacities for causing disseminated disease in the blood of C3H/HeJ mice during early infection. Results: Borrelia burgdorferi B515, a clinical isolate that causes disseminated infection in mice, differentially regulated 236 transcripts (P<0.05 by ANOVA, with fold change of at least 2). The 216 significantly induced transcripts included IFN-responsive genes and genes involved in immunity and inflammation. In contrast, B. burgdorferi B331, a clinical isolate that causes transient skin infection but does not disseminate in C3H/HeJ mice, stimulated changes in only a few genes (1 induced, 4 repressed). Transcriptional regulation of type I IFN and IFN-related genes was measured by quantitative RT-PCR in mouse skin biopsies collected from the site of infection 24 hours after inoculation with B. burgdorferi. The mean values for transcript of Ifnb, Cxcl10, Gbp1, Ifit1, Ifit3, Irf7, Mx1, and Stat2, were found to be significantly increased in B. burgdorferi strain B515-infected mice relative to the control group. In contrast, transcription of these genes was not significantly changed in response to B. burgdorferi strain B331 or B31-4, a mutant that is unable to disseminate. Conclusions: These results establish a positive association between the disseminating capacity of B. burgdorferi and early type I IFN induction in a murine model of Lyme disease.
Project description:Macrophages mediate the elimination of pathogens by phagocytosis resulting in the activation of specific signaling pathways that lead to the production of cytokines, chemokines and other factors. Borrelia burgdorferi, the causative agent of Lyme disease, causes a wide variety of pro-inflammatory symptoms. The proinflammatory capacity of macrophages is intimately related to the internalization of the spirochete. However, most receptors mediating this process are largely unknown. We have applyedapplied a multiomic approach, including the proteomic analysis of B. burgdorferi-containing phagosome-enriched fractions, to identify surface receptors that are involved in the phagocytic capacity of macrophages as well as their inflammatory output. Sucrose gradient protein fractions of human monocyte-derived macrophages exposed to B. burgdorferi contained the phagocytic receptor, CR3/CD14 highlighting the major role played by these proteins in spirochetal phagocytosis. Among others, Other proteins identified proteins include C-type lectins, scavenger receptors or siglecs, and contain uPAR and MARCO. We also identified the Fc gamma receptor pathway as involved both in the phagocytosis of , and TNF induction by B. burgdorferi in the absence of antibodies. The common gamma chain, FcR, mediates the phagocytosis of the spirochete, likely through Fc receptors and C-type lectins, in a process that involves Syk activation. Overall, these findings highlight the complex array of receptors involved in the phagocytic response of macrophages to B. burgdorferi.
Project description:Transcriptional profiling of gene expression between parental strain B31 and rrp1 mutant. Cyclic-di-GMP is a bacterial second messenger that modulates many biological processes. Although its role in bacterial pathogenesis during mammalian infection has been widely recognized, the role of c-di-GMP in pathogen's life cycle in vector hosts is less understood. The enzootic cycle of the Lyme disease pathogen Borrelia burgdorferi involves both a mammalian host and an Ixodes tick vector. The B. burgdorferi genome encodes a single copy of the diguanylate cyclase gene (rrp1), which is responsible for the production of c-di-GMP. To determine the role of c-di-GMP in the life cycle of B. burgdorferi, an Rrp1-deficient B. burgdorferi strain was generated. The rrp1 mutant remains infectious in the mammalian host, but could not survive in the tick vector. To identify the mechanisms of Rrp1 contributing to B. burgdorferi pathogenesis and gene regulation, microarray was employed to compare gene expression profiles between the parental strain B31 and the rrp1 mutant.
Project description:Borrelia burgdorferi, the etiological agent of Lyme disease, persists in nature through an enzootic cycle consisting of a vertebrate host and an Ixodes tick vector. The sequence motifs modified by two well-characterized restriction/modification loci of B. burgdorferi type strain B31 were recently described, but the methylation profiles of other Lyme disease Borrelia have not been characterized. Herein, the methylomes of B. burgdorferi type strain B31 and 7 clonal derivatives, along with B. burgdorferi N40, B. burgdorferi 297, B. burgdorferi CA-11, B. afzelii PKo, B. afzelii BO23, and B. garinii PBr, were defined through PacBio SMRT sequencing. This analysis revealed 9 novel sequence motifs methylated by the plasmid-encoded restriction/modification enzymes of these Borrelia strains. Furthermore, while a previous analysis of B. burgdorferi B31 revealed an epigenetic impact of methylation on the global transcriptome, the current data contradict those findings; our analyses of wild-type B. burgdorferi B31 revealed no consistent differences in gene expression among isogenic derivatives lacking one or more restriction/modification enzyme(s).
Project description:Lyme carditis is an extracutaneous manifestation of Lyme disease characterized by episodes of atrioventricular block of varying degrees and other less reported cardiomyopathies. The molecular changes associated with the response to Borrelia burgdorferi over the course of infection are poorly understood. Here, we identify broad transcriptomic and proteomic changes in the heart during infection that reveal a profound downregulation of mitochondrial components. We also characterize the long-term functional modulation of macrophages exposed to live bacteria, characterized by an augmented glycolytic output, increased spirochetal binding and internalization, and reduced IRF-4-dependent inflammatory responses. In vitro, glycolysis inhibition reduces the production of TNF by memory macrophages whereas in vivo, it produces the reversion of the Irf4-induced memory phenotype, the recovery of tissue mitochondrial components, and decreased inflammation and spirochetal burdens. These results show that B. burgdorferi induces long-term, memory-like responses in macrophages with tissue-wide consequences that are amenable to be manipulated in vivo.