Our goal is to understand the mechanisms of innate immunity at the molecular level. The innate immune system provides the body with its first line of defense against infections and is crucial for survival. Many human diseases result from a failure of the innate immune system. In order to identify and characterize novel mechanisms and effectors of the innate immune system, we will use the infections of C. elegans by several human bacterial pathogens - Pseudomonas aeruginosa, Salmonella enterica and Enterococcus faecalis - as a model. C. elegans is an excellent model for the study of innate immunity; it allows us to combine the power of genetic and functional genomic approaches to systematically and comprehensively dissect the innate immune system. ? ? For this proposal, we seek to address the following questions. Within a single organism, what are the molecules that make up the innate immune system? What intracellular pathways are triggered in response to infections by different classes of bacterial pathogens? What molecules are produced that directly destroy or inhibit the growth of the invading pathogens? We will use a variety of approaches, including the combination of genetic screens, full genome gene expression profiling, bioinformatic searches for homologous sequences known to be involved in the innate immune response, and epigenetic inhibition of gene function by double-stranded RNA interference (RNAi) to address the above questions. C. elegans has an inducible defense system and uses the evolutionarily conserved MAP kinase and TGF-beta pathways for defense against bacterial infection. The MAP kinase and TGF-beta pathways have also been implicated in innate immune response in Drosophila and in mice, respectively. Thus, we also propose to identify downstream targets to the TGF-beta pathway, and to determine how the TGF-beta pathway interacts with the MAP kinase pathway in mediating antibacterial defense. Because the signaling pathways in anti-bacterial defense are conserved across phylogeny, these studies should provide significant insights into anti-bacterial response in other organisms, including humans.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM066269-02
Application #
6619868
Study Section
Cell Development and Function Integrated Review Group (CDF)
Program Officer
Somers, Scott D
Project Start
2002-08-01
Project End
2007-07-31
Budget Start
2003-08-01
Budget End
2004-07-31
Support Year
2
Fiscal Year
2003
Total Cost
$333,625
Indirect Cost
Name
Stanford University
Department
Genetics
Type
Schools of Medicine
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
Alegado, Rosanna A; Chin, Chui-Yoke; Monack, Denise M et al. (2011) The two-component sensor kinase KdpD is required for Salmonella typhimurium colonization of Caenorhabditis elegans and survival in macrophages. Cell Microbiol 13:1618-37
Glauser, Dominique A; Chen, Will C; Agin, Rebecca et al. (2011) Heat avoidance is regulated by transient receptor potential (TRP) channels and a neuropeptide signaling pathway in Caenorhabditis elegans. Genetics 188:91-103
Mansisidor, Andres R; Cecere, Germano; Hoersch, Sebastian et al. (2011) A conserved PHD finger protein and endogenous RNAi modulate insulin signaling in Caenorhabditis elegans. PLoS Genet 7:e1002299
Kawli, Trupti; Wu, Clay; Tan, Man-Wah (2010) Systemic and cell intrinsic roles of Gqalpha signaling in the regulation of innate immunity, oxidative stress, and longevity in Caenorhabditis elegans. Proc Natl Acad Sci U S A 107:13788-93
Nandakumar, Madhumitha; Tan, Man-Wah (2008) Gamma-linolenic and stearidonic acids are required for basal immunity in Caenorhabditis elegans through their effects on p38 MAP kinase activity. PLoS Genet 4:e1000273
Evans, Eric A; Chen, Will C; Tan, Man-Wah (2008) The DAF-2 insulin-like signaling pathway independently regulates aging and immunity in C. elegans. Aging Cell 7:879-93
Muir, Rachel E; Tan, Man-Wah (2008) Virulence of Leucobacter chromiireducens subsp. solipictus to Caenorhabditis elegans: characterization of a novel host-pathogen interaction. Appl Environ Microbiol 74:4185-98
Kawli, Trupti; Tan, Man-Wah (2008) Neuroendocrine signals modulate the innate immunity of Caenorhabditis elegans through insulin signaling. Nat Immunol 9:1415-24
Alegado, Rosanna A; Tan, Man-Wah (2008) Resistance to antimicrobial peptides contributes to persistence of Salmonella typhimurium in the C. elegans intestine. Cell Microbiol 10:1259-73
Kurz, C Leopold; Shapira, Michael; Chen, Karen et al. (2007) Caenorhabditis elegans pgp-5 is involved in resistance to bacterial infection and heavy metal and its regulation requires TIR-1 and a p38 map kinase cascade. Biochem Biophys Res Commun 363:438-43

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