Murine norovirus (MNV) is emerging as a potential pathogen in mice and its prevalence in research facilities around the world is causing concern among investigators using mice. Initially, the virus was reported to cause morbidity and mortality only in immunocompromised mice while it did not cause any clinical signs of overt diseases in immunocompetent mice. However, we found that MNV infection can induce subtle changes in immune responses even in wild type mice and that MNV infection was associated with an increase in aortic sinus lesion size in Ldlr-/- mice, a commonly used mouse model for atherosclerosis research. We observed that larger aortic sinus lesions in MNV infected mice were associated with increased numbers of macrophages. Others have reported that MNV has a tropism toward macrophages as well as dendritic cells. Our preliminary studies have also found that MNV infection alters the production of several inflammatory cytokines in bone marrow derived macrophages. Thus, we hypothesize that MNV is a potential intercurrent variable in atherosclerosis research partly by influencing macrophage recruitment, cytokine/chemokine profile, and or accumulation in atherosclerotic lesions. To test our hypothesis, we will first determine whether MNV infection exacerbates atherosclerosis in an additional mouse model, ApoE-/- mice. Next, we will investigate whether early exposure (before onset of atherosclerosis) to MNV alters disease phenotype in two commonly used mouse models, Ldlr-/- and ApoE-/-. Finally we will determine how MNV might alter the disease outcome by examining changes in macrophages, important innate immune cells involved in disease initiation and progression. Proposed studies in this application will provide information that can be used to determine whether time and effort should be invested in elimination of MNV from mouse research facilities. Thus, our application is in line with the objective of the current RFA to support investigation of "the impact of murine norovirus infection on immune responses".

Public Health Relevance

Murine norovirus is prevalent in mouse research facilities across the United States. Our studies will investigate the effects of MNV on studies of murine models of atherosclerosis and provide information for determining whether mouse colonies should be maintained MNV-free to reduce variability in studies using these models.

Agency
National Institute of Health (NIH)
Institute
Office of The Director, National Institutes of Health (OD)
Type
Exploratory/Developmental Grants (R21)
Project #
8R21OD011135-02
Application #
8306671
Study Section
Special Emphasis Panel (ZRR1-CM-4 (01))
Program Officer
Moro, Manuel H
Project Start
2011-08-01
Project End
2013-06-30
Budget Start
2012-07-01
Budget End
2013-06-30
Support Year
2
Fiscal Year
2012
Total Cost
$231,750
Indirect Cost
$81,750
Name
University of Washington
Department
Veterinary Sciences
Type
Schools of Medicine
DUNS #
605799469
City
Seattle
State
WA
Country
United States
Zip Code
98195