Initial Steps of Murine Norovirus Infection in vivo and in vitro.

Norovirus;Murine norovirus;M cells;Virus entry;virus binding;Infection;CD36;CD44;CD98;Transferrin receptor 1;Microbiology and Immunology;Science;Microbiology & Immunology

Bragazzi Cunha, JulianaSpindler, Katherine ;

University of Michigan

关键词: Norovirus;    Murine norovirus;    M cells;    Virus entry;    virus binding;    Infection;    CD36;    CD44;    CD98;    Transferrin receptor 1;    Microbiology and Immunology;    Science;    Microbiology & Immunology;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/135831/bragazzi_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Human noroviruses (HuNoVs) are the leading cause of acute gastroenteritis worldwide. Despite their major impact on public health and economy, little is known about how HuNoVs interact with their host during infection. Murine norovirus (MNV) is genetically related to HuNoVs and is commonly used to study norovirus-host interactions and basic aspects of norovirus biology. In this dissertation, we aimed to characterize the initial steps of MNV infection at the host and cellular levels.Microfold (M) cells are specialized intestinal epithelial cells for transporting lumenal antigens across the epithelial barrier by transcytosis. We are interested in the role M cells play in MNV infection in vivo. Previous data from our lab showed that oral MNV infection is significantly reduced in BALB/c mice depleted of M cells and absent in Rag2null/γcnull mice. To expand the study on the role of M cells in MNV infection, we used a conditional knockout mouse model of M cell deficiency (C57BL/6 background). Unlike our previous findings, mice deficient in M cells (M-less mice) and littermates had similar MNV-1 and MNV.CR3 yields, suggesting M cells are not required during MNV infection in this model. However, M-less mice infected with MNV-1 had significantly reduced viral titers in the MLN, which suggests that trafficking of MNV-1 from the intestinal lumen to the MLN is M cell-dependent.A key determinant of noroviruses’ cell tropism and species-specificity is expression of host cellular attachment/entry receptors. We investigated whether host cellularproteins play a role during the early steps of norovirus infection. Using VOPBA followed byMS/MS analysis in two permissive cell lines, RAW264.7 (macrophage-like) and SRDC (DC-like), four cellular membrane proteins were identified as candidates. Loss-of-function studies revealed that CD36 and CD44 promoted MNV-1 binding to primary dendritic cells, while CD98 and transferrin receptor 1 (TfRc) facilitated MNV-1 binding to RAW 264.7 cells. Furthermore, MNV-1 P domain interacted directly with the extracellular domains of recombinant CD36, CD98 and TfRc by ELISA. Additionally, CD98 may play a role in post-binding stages of MNV-1 infection. Our studies demonstrated that multiple membrane proteins can promote efficient MNV-1 infection in a cell type-specific manner.