One of the primary focus projects of our laboratory program centers on the eosinophil, an enigmatic leukocyte whose role in host defense remains a subject of significat controversy. Several lines of investigation from our laboratory have led us to consider the role of the eosinophil secretory ribonucleases (described further in Project Number AI000942-01), and by extension, the role of their primary host cells, the eosinophils, in host defense against a previously unrecognized group of target pathogens, specifically respiratory viruses of the family Paramyxoviridae (described further in Project Number AI000943-01). As part of our larger interest in eosinophils and their role in inflammation, we have initiated an extensive gene microarray study designed to explore the nature and development of mouse eosinophils in vivo. The results of this work, entitled--Gene microarray analysis reveals interleukin-5-dependent transcriptional targets in mouse bone marrow--were published in Blood in early 2004 (ref #3) and were augmented by a followup study entitled--Plasminogen activator inhibitor-2 (PAI-2) in eosinophilic leukocytes--(ref #15). Among the most prominent findings of the first study, we observed 7 to 40-fold increased expression of transcripts encoding the classic eosinophil granule proteins (eosinophil peroxidase, major basic protein, the ribonucleases) together with arachidonate-15-lipoxygenase and protease inhibitor PAI-2, in the IL-5-producing, infected wild type mice only. This was accompanied by increased transcription of genes involved in secretory protein biosynthesis and granule-vesicle formation. Interestingly, we did not detect increased expression of genes encoding eosinophil-related chemokine receptors (CCR1, CCR3) or members of the GATA or C/EBP transcription factor families. These data suggest that the IL-5 responsive progenitors in the mouse bone marrow are already significantly committed to the eosinophil lineage, and that IL-5 promotes differentiation of these committed progenitors into cells with recognizable and characteristic cytoplasmic granules and granule proteins. In the followup study (ref #15), we demonstrated that immunoreactive PAI-2 protein present in extracts of purified human eosinophils at variable concentrations ranging from 30 to 444 ng/10E6 cells, which is the highest per cell concentration among all leukocyte subtypes evaluated. Enzymatic assay confirmed that eosinophil-derived PAI-2 is biologically active and inhibits activation of its preferred substrate, urokinase (u-PA), and further studies demonstrated localization in the specific granules. Immunoreactive PAI-2 was also detected in extracellular deposits in and around the eosinophil-enriched granuloma tissue encapsulating the parasitic egg in livers of wild type mice infected with the helminthic parasite, Schistosoma mansoni. We are currently exploring the role of this protease inhibitor in both PAI-2 and various eosinophil-depleted or eosinophil-devoid strains of gene-deleted mice.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Intramural Research (Z01)
Project #
1Z01AI000941-01
Application #
6987123
Study Section
(LAD)
Project Start
Project End
Budget Start
Budget End
Support Year
1
Fiscal Year
2004
Total Cost
Indirect Cost
Name
Niaid Extramural Activities
Department
Type
DUNS #
City
State
Country
United States
Zip Code
Foster, Paul S; Maltby, Steven; Rosenberg, Helene F et al. (2017) Modeling TH 2 responses and airway inflammation to understand fundamental mechanisms regulating the pathogenesis of asthma. Immunol Rev 278:20-40
Percopo, Caroline M; Brenner, Todd A; Ma, Michelle et al. (2017) SiglecF+Gr1hi eosinophils are a distinct subpopulation within the lungs of allergen-challenged mice. J Leukoc Biol 101:321-328
Kraemer, Laura S; Brenner, Todd A; Krumholz, Julia O et al. (2017) A flow-cytometric method to evaluate eosinophil-mediated uptake of probiotic Lactobacillus reuteri. J Microbiol Methods 137:19-24
Rosenberg, Helene F; Druey, Kirk M (2016) Eosinophils, galectins, and a reason to breathe. Proc Natl Acad Sci U S A 113:9139-41
Rosenberg, Helene F; Masterson, Joanne C; Furuta, Glenn T (2016) Eosinophils, probiotics, and the microbiome. J Leukoc Biol 100:881-888
Rosenberg, Helene F (2015) Eosinophil-Derived Neurotoxin (EDN/RNase 2) and the Mouse Eosinophil-Associated RNases (mEars): Expanding Roles in Promoting Host Defense. Int J Mol Sci 16:15442-55
Percopo, Caroline M; Dyer, Kimberly D; Ochkur, Sergei I et al. (2014) Activated mouse eosinophils protect against lethal respiratory virus infection. Blood 123:743-52
Rosenberg, Helene F; Dyer, Kimberly D; Foster, Paul S (2013) Eosinophils: changing perspectives in health and disease. Nat Rev Immunol 13:9-22
Rosenberg, Helene F (2013) Editorial: mouse eosinophils expressing Cre recombinase: endless ""flox""ibilities. J Leukoc Biol 94:3-4
Doyle, Alfred D; Jacobsen, Elizabeth A; Ochkur, Sergei I et al. (2013) Expression of the secondary granule proteins major basic protein 1 (MBP-1) and eosinophil peroxidase (EPX) is required for eosinophilopoiesis in mice. Blood 122:781-90

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