Date of Award
Spring 5-2017
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Biological Sciences
Committee Chair
Fengwei Bai
Committee Chair Department
Biological Sciences
Committee Member 2
Glenmore Shearer Jr.
Committee Member 2 Department
Biological Sciences
Committee Member 3
Mohamed O. Elasri
Committee Member 3 Department
Biological Sciences
Committee Member 4
Yanlin Guo
Committee Member 4 Department
Biological Sciences
Committee Member 5
Faqing Huang
Committee Member 5 Department
Chemistry and Biochemistry
Abstract
West Nile virus (WNV) is a positive-sensed, single-stranded RNA flavivirus that can cause human neuroinvasive diseases, including encephalitis, meningitis, and flaccid paralysis. The mechanisms by which WNV enters the central nervous system and the host-factors that are involved in WNV-neuroinvasiveness are not completely understood. Osteopontin (OPN), a multifunctional glycoprotein, has been implicated as a bio-marker for a number of neuroinflammatory diseases. In particular, secreted (s)OPN has been implicated to participate in recruitment of polymorphonuclear neutrophils (PMN) to sites of its expression, while PMNs have been suggested to act as WNV reservoirs. Therefore, sOPN recruitment of PMNs may contribute to neuroinvasive WNV infection via the ‘Trojan horse’ mechanism of viral entry into the brain. Therefore, we hypothesize brain-infiltration of PMNs during neuroinvasive WNV pathogenesis is in part mediated by sOPN. Our results show that sOPN expression was significantly increased in human sera, human neuronal cells line, murine plasma, brain homogenates and primary neuronal supernatant following WNV infection, indicating a role for OPN in WNV pathogenesis. In addition, after challenge with WNV in vivo, Opn-/- mice exhibited a higher (70%) survival rate than wild-type (WT) mice (30%). Consistent with this, qPCR analysis between WT and Opn-/- mice demonstrated comparable levels of viremia; yet, reduced viral burden in the brains of Opn-/-mice compared to WT controls. Analysis of brain-
infiltrating leukocytes displayed reduced PMNs and PMN-chemokine expression levels in Opn-/- mice brains. Importantly, intracerebral supplement of recombinant OPN (rOPN) into Opn-/-mice resulted in increased PMN-brain infiltration, increased viral load and reduced overall survival. Together, these data suggest OPN facilitates WNV neuroinvasion in a mouse model.
ORCID ID
0000-0002-1657-3618
Copyright
2017, Amber Marie Paul
Recommended Citation
Paul, Amber M., "A Novel Role for Osteopontin in Facilitating West Nile Virus Neuroinvasion" (2017). Dissertations. 1367.
https://aquila.usm.edu/dissertations/1367
Included in
Immunology of Infectious Disease Commons, Other Neuroscience and Neurobiology Commons, Virus Diseases Commons