Panthogenic Mechanism of Leptospira Species Based on the Interaction of Leptospires and Host Cells

Leptospirosis is a zoonotic disease that is now recognized as a re-emerging infectious disease, particularly in tropical and sub-tropical regions where flooding frequently occurs. It is significant caused by spirochetes belonging to diverse pathogenic species within the genus Leptospira that vary in their distribution in nature and depend on different modes of transmission. Exposure of mucous membranes or abrased skin to water or soil contaminated with leptospires shed in animal urine can lead to a systemic inflammation syndrome with frequent sever renal damage. Much work has to be done to elucidate many aspects of Leptospira pathogenic factors on the basis of the knowledge on host and bacteria interactions. However, the mechanisms by which Leptospires invasiveness and adherence to the host were poorly understood. According to previous studies, Leptospires possess unusual lipopolysaccharides that have been shown to use Toll-like receptor 2 instead of Toll-like receptor 4 for signaling in macrophages. To understand whether lipopolysaccharides of Leptospira spp. response to human renal tubule epithelial cells through a Toll-like receptor 2-mediated pathway and their interaction is direct binding, we will focus on the relationship between the structure and function of leptospiral lipopolysaccharides. Firstly, the gene organization in the lipopolysaccharide biosynthetic locus will be analyzed in Leptospira santarosai serovar Shermani and characterized lipopolysaccharides synthesized in Leptospires. Secondly, we will investigate whether the Toll-like receptor 4 and Toll-like receptor 2, which are present on renal tubular epithelium and potentially detect leptospiral lipopolysaccharides. Hence, this study will use the serial analysis of gene expression procedure in lipopolysaccharides-stimulated human renal tubule epithelial cells and to establish infection animal model. A better understanding of the molecular processes involved in leptospiral lipopolysaccharides- stimulated and non-stimulated renal epithelial cells signalling will provide the basis for better understanding of human leptospiral infection. Finally, the structure of leptospiral lipopolysaccharides will be elucidated and to examine the binding between leptospiral lipopolysaccharides and Toll-like receptor 2 by Atomic force microscopy force-distance analysis. In this study, we will characterize the structure of leptospiral lipopolysaccharides in relationship to cell signaling and TLR recognition. To date, novel antibiotics, vaccines and anti-flammatory agents are likely to emerge from an in depth understanding of leptospiral lipopolysaccharides-host protein interaction at the atomic level. In addition, an interdisciplinary experimental approach in studies of leptospira lipopolysaccharides will be needed in this project such as genomics, structure biology and animal models. Year 1. 1. Genomic analysis of lipopolysaccharide biosynthesis of L. santarosai serovar Shermani in sequencing genome 2. To clarify lipopolysaccharides profile among Leptospira species 3. To produce antibody raised against lipopolysaccharides of L. interrogans serovar Lai (Major serovar in Mainland China) and L. santarosai serovar Shermani (Major serovar in Taiwan) Year 2. 1. To clarify which genes involved in lipopolysaccharides of Leptospira spp. stimulated human renal tubule epithelial cells 2. To assess the biological activity of lipopolysaccharides of Leptospira spp. during infection by luminescent Leptospira mutant and wild type (The study will be collaborated with Professor Jie Yan, Zhejiang University in China) 3. To determine if lipopolysaccharides of L. santorosai serovar Shermani stimulate renal tubule epithelial cells through a Toll-like receptor 2-mediated pathway. Year 3. 1. To clarify the structure of lipopolysaccharides of L. santarosai serovar Shermani 2. To evaluate the direct interaction between Leptospira lipopolysaccharides and Toll-like receptor complex. Finally, this study would disclose important pathogen in Mainland China and Taiwan of their related lipopolysaccharides that is pertinent to understanding the pathogen-host interaction via genomic and structural analysis of leptospirosis and pathogenesis of infection related renal disease in Taiwan.

Project ID:PC10107-0134
External Project ID:NSC101-2321-B182-007-MY3