Bacterial growth and division requires constant degradation and reassembly of the peptidoglycan cell wall. This process generates small peptidoglycan fragments that can be released by the bacteria and sensed by host cells, often inducing an inflammatory response. In infections caused by Neisseria gonorrhoeae, Bordetella pertussis, or Shigella flexneri, peptidoglycan fragments are thought to induce a large inflammatory response that exacerbates disease or is largely responsible for the cell damage occurring during the disease. In the organ culture model of gonococcal pelvic inflammatory disease, these peptidoglycan fragments recapitulate the tissue damage seen in women with the disease. The mechanisms for toxic peptidoglycan fragment production and subsequent release are not known for any of the bacteria that release these fragments. Furthermore bacteria can affect the host response by processing the peptidoglycan in different ways, resulting in detection and signaling through different pathways. In N. gonorrhoeae the composition of released peptidoglycan fragments is different from that which makes up the cell wall, suggesting that the bacteria may specifically process peptidoglycan fragments from cell wall degradation to produce specific products that alter or effect host cell processes. In these studies we will identify enzymes important for the production and release of toxic peptidoglycan fragments by N. gonorrhoeae, characterize the function of these enzymes, produce mutants defective in enzyme function and thus defective in toxic fragment production, and determine the effects of different released peptidoglycan fragments in gonococcal infection of primary human neutrophils and Fallopian tube tissue.

Public Health Relevance

Peptidoglycan fragments cause inflammatory responses that exacerbate disease in several bacterial infections. These studies will determine the mechanisms by which these virulence factors are created in the bacterial pathogen Neisseria gonorrhoeae and generate mutants that will be used to determine the molecular mechanisms by which such peptidoglycan fragments cause this destructive response.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI097157-01A1
Application #
8369673
Study Section
Bacterial Pathogenesis Study Section (BACP)
Program Officer
Hiltke, Thomas J
Project Start
2012-05-01
Project End
2017-04-30
Budget Start
2012-05-01
Budget End
2013-04-30
Support Year
1
Fiscal Year
2012
Total Cost
$484,053
Indirect Cost
$157,054
Name
University of Wisconsin Madison
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
Obergfell, Kyle P; Schaub, Ryan E; Priniski, Lauren L et al. (2018) The low-molecular-mass, penicillin-binding proteins DacB and DacC combine to modify peptidoglycan cross-linking and allow stable Type IV pilus expression in Neisseria gonorrhoeae. Mol Microbiol :
Ragland, Stephanie A; Humbert, Mar?a V; Christodoulides, Myron et al. (2018) Neisseria gonorrhoeae employs two protein inhibitors to evade killing by human lysozyme. PLoS Pathog 14:e1007080
PĂ©rez Medina, Krizia M; Dillard, Joseph P (2018) Antibiotic Targets in Gonococcal Cell Wall Metabolism. Antibiotics (Basel) 7:
Knilans, Kayla J; Hackett, Kathleen T; Anderson, James E et al. (2017) Neisseria gonorrhoeae Lytic Transglycosylases LtgA and LtgD Reduce Host Innate Immune Signaling through TLR2 and NOD2. ACS Infect Dis 3:624-633
Lenz, Jonathan D; Hackett, Kathleen T; Dillard, Joseph P (2017) A Single Dual-Function Enzyme Controls the Production of Inflammatory NOD Agonist Peptidoglycan Fragments by Neisseria gonorrhoeae. MBio 8:
Schaub, Ryan E; Dillard, Joseph P (2017) Digestion of Peptidoglycan and Analysis of Soluble Fragments. Bio Protoc 7:
Ragland, Stephanie A; Schaub, Ryan E; Hackett, Kathleen T et al. (2017) Two lytic transglycosylases in Neisseria gonorrhoeae impart resistance to killing by lysozyme and human neutrophils. Cell Microbiol 19:
Chan, Jia Mun; Dillard, Joseph P (2017) Attention Seeker: Production, Modification, and Release of Inflammatory Peptidoglycan Fragments in Neisseria Species. J Bacteriol 199:
Chan, Jia Mun; Dillard, Joseph P (2016) Neisseria gonorrhoeae Crippled Its Peptidoglycan Fragment Permease To Facilitate Toxic Peptidoglycan Monomer Release. J Bacteriol 198:3029-3040
Schaub, Ryan E; Chan, Yolande A; Lee, Mijoon et al. (2016) Lytic transglycosylases LtgA and LtgD perform distinct roles in remodeling, recycling and releasing peptidoglycan in Neisseria gonorrhoeae. Mol Microbiol 102:865-881

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