The dormant spores of Bacillus anthracis, the causative agent of anthrax, infect human or animal hosts and tether microbial development to disease pathogenesis. Following pathogen crossing of host epithelia and engulfment by macrophages, spore germination and outgrowth of vegetative cells occurs within phagosomes. Bacilli subsequently escape phagosomal membranes and replicate in the cytoplasm of macrophages. Infected macrophages are eventually lysed, and bacilli then multiply extracellularly in all tissues, including blood, liver, spleen, lungs, brain and intestines. The y-D-polyglutamic acid capsule of B. anthracis provides for resistance to phagocytic killing. Secretion of edema toxin as well as lethal toxin induces apoptosis of immune cells and endothelial tissues. These events mediate host killing, which is followed by spore formation, environmental dissemination and transmission to new hosts. This proposal investigates the role of sortases andanchored surface proteins during the four stages of anthrax pathogenesis - (i) spore entry, (ii) invasion of vegetative bacilli into macrophages or host tissues, (iii) extracellular replication of bacilli, and (iv)spore formation in deceased hosts. Two sortase genes are expressed in vegetative bacilli and under iron starvation conditions (srtA and srtB), as occurs in host tissues. A third sortase gene (srtQ is only expressed during spore formation. Each sortase recognizes specific sorting signals and anchors surface protein substrates in the bacterial envelope, thereby contributing unique properties to the infectious life cycle of B. anthracis. Sortase C anchored BasH and Basl are deposited in spore peptidoglycan. A new and exciting mechanism of spore envelope assembly is described here, as srtC is essential for the formation of infectious spores in host tissues. Sortase B anchored BasK is required for heme-iron scavenging, whereas sortase A anchored BasC and internalin-like BasJ are involved in macrophage replication. Using B. anthracis strains Sterne and Ames for genetic and biochemical analysis, the molecular mechanisms of surface protein and sortase function in anthrax pathogenesis will be addressed. B. anthracis is an important bioterror threat agent and this research proposal will provide future therapeutic and preventive interventions by revealing the underlying biological phenomena of anthrax pathogenesis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI069227-05
Application #
8005495
Study Section
Bacterial Pathogenesis Study Section (BACP)
Program Officer
Breen, Joseph J
Project Start
2007-01-01
Project End
2011-12-31
Budget Start
2011-01-01
Budget End
2011-12-31
Support Year
5
Fiscal Year
2011
Total Cost
$359,092
Indirect Cost
Name
University of Chicago
Department
Genetics
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
Nguyen-Mau, Sao-Mai; Oh, So-Young; Schneewind, Daphne I et al. (2015) Bacillus anthracis SlaQ Promotes S-Layer Protein Assembly. J Bacteriol 197:3216-27
Liszewski Zilla, Megan; Lunderberg, J Mark; Schneewind, Olaf et al. (2015) Bacillus anthracis lcp Genes Support Vegetative Growth, Envelope Assembly, and Spore Formation. J Bacteriol 197:3731-41
Oh, So-Young; Richter, Stefan G; Missiakas, Dominique M et al. (2015) Glutamate Racemase Mutants of Bacillus anthracis. J Bacteriol 197:1854-61
Lunderberg, J Mark; Liszewski Zilla, Megan; Missiakas, Dominique et al. (2015) Bacillus anthracis tagO Is Required for Vegetative Growth and Secondary Cell Wall Polysaccharide Synthesis. J Bacteriol 197:3511-20
Liszewski Zilla, Megan; Chan, Yvonne G Y; Lunderberg, Justin Mark et al. (2015) LytR-CpsA-Psr enzymes as determinants of Bacillus anthracis secondary cell wall polysaccharide assembly. J Bacteriol 197:343-53
Wang, Ya-Ting; Missiakas, Dominique; Schneewind, Olaf (2014) GneZ, a UDP-GlcNAc 2-epimerase, is required for S-layer assembly and vegetative growth of Bacillus anthracis. J Bacteriol 196:2969-78
Wang, Ya-Ting; Oh, So-Young; Hendrickx, Antoni P A et al. (2013) Bacillus cereus G9241 S-layer assembly contributes to the pathogenesis of anthrax-like disease in mice. J Bacteriol 195:596-605
Oh, So-Young; Maier, Hannah; Schroeder, Jay et al. (2013) Vaccine protection against Bacillus cereus-mediated respiratory anthrax-like disease in mice. Infect Immun 81:1008-17
Lunderberg, J Mark; Nguyen-Mau, Sao-Mai; Richter, G Stefan et al. (2013) Bacillus anthracis acetyltransferases PatA1 and PatA2 modify the secondary cell wall polysaccharide and affect the assembly of S-layer proteins. J Bacteriol 195:977-89
Garufi, Gabriella; Wang, Ya-Ting; Oh, So-Young et al. (2012) Sortase-conjugation generates a capsule vaccine that protects guinea pigs against Bacillus anthracis. Vaccine 30:3435-44

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