Lentscher, Anthony
(2020)
Tissue-restricted chikungunya virus is attenuated in mice and protective against virulent virus challenge.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Chikungunya virus (CHIKV) is a mosquito-transmitted arthritogenic alphavirus that has reemerged to produce devastating epidemics of fever, rash, polyarthralgia, and polyarthritis. During natural infection in the mammalian host, CHIKV replicates in a variety of cell types, including keratinocytes, endothelial cells, macrophages, and skeletal muscle. The contribution of CHIKV replication in discrete cell types to pathogenesis is unclear. To understand the role of CHIKV tropism in pathogenesis, target sequences corresponding to various tissue-specific miRNAs were engineered into the genome of clinical CHIKV isolate SL15649. Replication kinetics of these viruses were assessed alongside mismatch-control strains engineered to contain synonymous mutations in miR-target sequences to alleviate miRNA-mediated restriction. A CHIKV strain incapable of replication in skeletal muscle, SKE, and its mismatch control, SKE MM, were found to replicate with anticipated kinetics in vitro. In situ hybridization of limb sections from infected C57BL/6 mice using a CHIKV RNA-specific probe showed diminished SKE replication in myofibers in the interosseous muscle of the left rear foot adjacent to the site of inoculation, though both SKE and SKE MM replicated comparably in connective tissue that does not express the restrictive miRNA. Mice infected with SKE displayed diminished hind limb swelling and inflammation and necrosis of the interosseous muscle compared to mice infected with SKE MM, despite comparable titers in musculoskeletal tissues at days 1, 3, and 7 post-inoculation. Additionally, SKE infection was associated with decreased production of IL-6, IL-1b, IP-10, and TNFa, as well as diminished infiltration of CD4+ T cells into the interosseous muscle. Treatment of mice with an antibody directed against the IL-6 receptor led to diminished footpad swelling in mice infected with SKE MM, reducing swelling to levels seen in mice infected with SKE. Additionally, vaccination with SKE protected mice against disease following challenge with WT SL15649. These data suggest that IL-6, which is released following infection of myofibers, is a critical mediator of CHIKV-induced inflammation and may represent a therapeutic target to alleviate CHIKV disease. Additionally, incorporation of skeletal muscle-specific miR-target sequences into the CHIKV genome may constitute a new method for developing live-attenuated vaccines.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
17 April 2020 |
| Date Type: |
Publication |
| Defense Date: |
10 February 2020 |
| Approval Date: |
17 April 2020 |
| Submission Date: |
1 April 2020 |
| Access Restriction: |
1 year -- Restrict access to University of Pittsburgh for a period of 1 year. |
| Number of Pages: |
170 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
School of Medicine > Microbiology and Immunology |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
chikungunya, arbovirus, pathogenesis, tropism |
| Date Deposited: |
17 Apr 2020 15:19 |
| Last Modified: |
17 Apr 2021 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/38529 |
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