PROJECT SUIVIMARY (See instructions): Francisella tularensis (Ft) is an intracellular Gram-negative bacterium that is highly pathogenic when aerosolized. We reason that the remarkable pathogenicity of aerosolized Ft reflects unique microbial features that render local innate host defenses in the lung quantitatively or qualitatively ineffective and hypothesize that specific surface features of Ft, including extracellular capsule-like material (CLM), subvert local pulmonary innate defenses, resulting in blunted host response in the lung and consequently the observed virulence of aerosolized Ft. As part of our comprehensive assessment of Ft-ain/vay innate host defense interaction and the contribution of CLM, Project 2 will examine alveolar epithelial cells (AEC), pulmonary microvascular endothelial cells (PMVEC) and neutrophils that traverse Ftstimulated AEC and PMVEC (rPMN) - three interconnected elements of early pulmonary innate host response. We will pursue the following two aims:
Aim 1 : To characterize the mechanisms and functional consequences of Ft resistance to endogenous pulmonary alveolar epithelial and endothelial cell defenses Do invading Ft or its CLM alter innate antimicrobial and proinflammatory responses of AEC and PMVEC? Do invading Ft alter PECAM-CD99 interactions involved in transmigration? Does Ft infection of AEC and PMVEC activate the inflammasome? Do interactions of AEC or PMVEC with Ft alter microbial phenotype and do such changes influence virulence? How do structural changes in CLM influence interactions between Ft and AEC or PMVEC and thereby alter PMN transmigration? How do ainway dendritic cells influence Ft invasion of AEC and AEC responses to invasion? Aim 2: To define the functional alterations In transmigrated PMN recruited by Ft that contribute to Ft virulence Does development of the rPMN phenotype require contact with Ft, shed bacterial components such as CLM, PMVEC-specific factor(s), or a combination of these elements? Does a similar phenotype develop in PMN that migrate across AEC? What is the functional phenotype of rPMN? What mechanism(s) underlie the depressed NADPH oxidase of rPMN? Do structural changes in Ft CLM alter interactions of Ft with PMVEC/AEC with subsequent effects on rPMN? Do rPMN that ingest Ft progress normally to undergo caspase-3-mediated apoptosis or are they redirected to a caspase-1-mediated proinflammatory cell death?

Public Health Relevance

As part of our PPG, these studies will provide important new insights regarding innate immune function in the lung, in general, and in the pathogenesis of the severe pneumonia caused by aerosolized Ft. Such new information is a prerequisite for the development of novel interventions to prevent and to treat infections with this virulent organism.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Program Projects (P01)
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Special Emphasis Panel (ZAI1-LG-I)
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University of Iowa
Iowa City
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Mashruwala, Ameya A; Pang, Yun Y; Rosario-Cruz, Zuelay et al. (2015) Nfu facilitates the maturation of iron-sulfur proteins and participates in virulence in Staphylococcus aureus. Mol Microbiol 95:383-409
Bandyopadhyay, Sarmistha; Long, Matthew E; Allen, Lee-Ann H (2014) Differential expression of microRNAs in Francisella tularensis-infected human macrophages: miR-155-dependent downregulation of MyD88 inhibits the inflammatory response. PLoS One 9:e109525
Nauseef, William M (2014) Diagnostic assays for myeloperoxidase and myeloperoxidase deficiency. Methods Mol Biol 1124:537-46
Rasmussen, Jed A; Post, Deborah M B; Gibson, Bradford W et al. (2014) Francisella tularensis Schu S4 lipopolysaccharide core sugar and O-antigen mutants are attenuated in a mouse model of tularemia. Infect Immun 82:1523-39
McCracken, Jenna M; Allen, Lee-Ann H (2014) Regulation of human neutrophil apoptosis and lifespan in health and disease. J Cell Death 7:15-23
Nauseef, William M (2014) Myeloperoxidase in human neutrophil host defence. Cell Microbiol 16:1146-55
Jones, Bradley D; Faron, Matthew; Rasmussen, Jed A et al. (2014) Uncovering the components of the Francisella tularensis virulence stealth strategy. Front Cell Infect Microbiol 4:32
Nauseef, William M (2014) Isolation of human neutrophils from venous blood. Methods Mol Biol 1124:13-8
Barker, Jason H; Kaufman, Justin W; Zhang, De-Sheng et al. (2014) Metabolic labeling to characterize the overall composition of Francisella lipid A and LPS grown in broth and in human phagocytes. Innate Immun 20:88-103
White, Mark J; Boyd, Jeffrey M; Horswill, Alexander R et al. (2014) Phosphatidylinositol-specific phospholipase C contributes to survival of Staphylococcus aureus USA300 in human blood and neutrophils. Infect Immun 82:1559-71

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