Chikungunya virus replication in skeletal muscle cells is required for disease development
Anthony J. Lentscher, Mary K. McCarthy, Nicholas A. May, Bennett J. Davenport, Stephanie A. Montgomery, Krishnan Raghunathan, Nicole McAllister, Laurie A. Silva, Thomas E. Morrison, Terence S. Dermody
Anthony J. Lentscher, Mary K. McCarthy, Nicholas A. May, Bennett J. Davenport, Stephanie A. Montgomery, Krishnan Raghunathan, Nicole McAllister, Laurie A. Silva, Thomas E. Morrison, Terence S. Dermody
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Research Article Infectious disease Virology

Chikungunya virus replication in skeletal muscle cells is required for disease development

Abstract

Chikungunya virus (CHIKV) is an arbovirus capable of causing a severe and often debilitating rheumatic syndrome in humans. CHIKV replicates in a wide variety of cell types in mammals, which has made attributing pathologic outcomes to replication at specific sites difficult. To assess the contribution of CHIKV replication in skeletal muscle cells to pathogenesis, we engineered a CHIKV strain exhibiting restricted replication in these cells via incorporation of target sequences for skeletal muscle cell–specific miR-206. This virus, which we term SKE, displayed diminished replication in skeletal muscle cells in a mouse model of CHIKV disease. Mice infected with SKE developed less severe disease signs, including diminished swelling in the inoculated foot and less necrosis and inflammation in the interosseous muscles. SKE infection was associated with diminished infiltration of T cells into the interosseous muscle as well as decreased production of Il1b, Il6, Ip10, and Tnfa transcripts. Importantly, blockade of the IL-6 receptor led to diminished swelling of a control CHIKV strain capable of replication in skeletal muscle, reducing swelling to levels observed in mice infected with SKE. These data implicate replication in skeletal muscle cells and release of IL-6 as important mediators of CHIKV disease.

Authors

Anthony J. Lentscher, Mary K. McCarthy, Nicholas A. May, Bennett J. Davenport, Stephanie A. Montgomery, Krishnan Raghunathan, Nicole McAllister, Laurie A. Silva, Thomas E. Morrison, Terence S. Dermody

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Figure 2

Replication of CHIKV containing muscle-specific miRNA target sequences is restricted in skeletal muscle.

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Replication of CHIKV containing muscle-specific miRNA target sequences i...
Three- to 4-week-old male C57BL/6J mice were inoculated in the left rear footpad with PBS (mock) or 103 PFU of SKE MM or SKE. Left ankle tissue was collected 3 days after inoculation and processed for either H&E staining or RNAscope in situ hybridization for CHIKV RNA. (A) Regions corresponding to high-magnification insets (×10) of the interosseous muscle are indicated in the overview micrographs (×0.5) by black boxes. Representative images of 3 (mock) or 6 (SKE MM and SKE) mice per group are shown. Scale bars: ×0.5, 6 mm; ×10, 300 μm. (B) Magnification insets ×20 with indicated CHIKV staining in myofibers (closed arrows) and connective tissue (open arrows). Scale bars: ×20, 150 μm. Images were acquired using an Aperio ScanScope XT slide scanner and processed with Aperio ImageScope software. (C) DAB signal corresponding to CHIKV staining in interosseous muscle was quantified using ImageJ software. Horizontal bars indicate mean CHIKV intensity. Error bars indicate SEM. P values were determined comparing SKE and SKE MM by 2-tailed Student’s t test. **P < 0.01.