Lyme disease, caused by the arthropod-borne spirochete Borrelia burgdorferi, is a multisystem disorder that can lead to dermatologic, cardiac, neurologic, and rheumatologic manifestations. B. burgdorferi is maintained in a complex enzootic cycle involving its arthropod vector (Ixodes ticks) and a rodent mammalian host. Little is known about how B. burgdorferi adapts to two such distinctly different host environments and causes disease. Our long-term objective is to elucidate molecular mechanisms underlying host adaptation of B. burgdorferi with the expectation that this work will lay the groundwork for the development of innovative approaches for the treatment of and prevention of Lyme disease. In this regard, we have identified a key regulator Rrp2 that is essential for differential gene expression during the spirochete's enzootic cycle. However, the upstream signaling pathway that activates Rrp2 remains unknown. In this proposal, we will employ the temperature-induced Rrp2 activation model to dissect the signaling pathway that leads to the activation of the Rrp2 pathway. In the first aim, we will determine the contributions of acetyl phosphate and the putative histidine kinases to the Rrp2 activation. In the second aim, we will investigate the molecular mechanism underlying constitutive activation of the Rrp2 pathway by the ospAB mutant.

Public Health Relevance

Outcomes of this proposal will elucidate the complex signal sensing mechanisms of the Rrp2 pathway, which will fill a major gap in our understanding of Bb host adaptation. These findings could lead to the developments of therapeutic targets and form a basis for developing strategies to block the enzootic cycle of Bb.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Exploratory/Developmental Grants (R21)
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Special Emphasis Panel (ZRG1-IDM-A (90))
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Breen, Joseph J
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Indiana University-Purdue University at Indianapolis
Schools of Medicine
United States
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Xiang, Xuwu; Yang, Youyun; Du, Jimei et al. (2017) Investigation of ospC Expression Variation among Borrelia burgdorferi Strains. Front Cell Infect Microbiol 7:131
Carrasco, Sebastian E; Yang, Youyun; Troxell, Bryan et al. (2015) Borrelia burgdorferi elongation factor EF-Tu is an immunogenic protein during Lyme borreliosis. Emerg Microbes Infect 4:e54
Ye, Meiping; Zhang, Jun-Jie; Fang, Xin et al. (2014) DhhP, a cyclic di-AMP phosphodiesterase of Borrelia burgdorferi, is essential for cell growth and virulence. Infect Immun 82:1840-9
He, Ming; Zhang, Jun-Jie; Ye, Meiping et al. (2014) Cyclic Di-GMP receptor PlzA controls virulence gene expression through RpoS in Borrelia burgdorferi. Infect Immun 82:445-52
Troxell, Bryan; Ye, Meiping; Yang, Youyun et al. (2013) Manganese and zinc regulate virulence determinants in Borrelia burgdorferi. Infect Immun 81:2743-52
Troxell, Bryan; Yang, X Frank (2013) Metal-dependent gene regulation in the causative agent of Lyme disease. Front Cell Infect Microbiol 3:79
He, Ming; Ouyang, Zhiming; Troxell, Bryan et al. (2011) Cyclic di-GMP is essential for the survival of the lyme disease spirochete in ticks. PLoS Pathog 7:e1002133
Xu, Haijun; He, Ming; He, Jane Jingyuan et al. (2010) Role of the surface lipoprotein BBA07 in the enzootic cycle of Borrelia burgdorferi. Infect Immun 78:2910-8
Xu, Haijun; He, Ming; Pang, Xiujuan et al. (2010) Characterization of the highly regulated antigen BBA05 in the enzootic cycle of Borrelia burgdorferi. Infect Immun 78:100-7