Chikungunya virus mobilizes the apoptotic machinery to invade host cell defenses

P Krejbich‐Trotot, M Denizot, JJ Hoarau… - The FASEB …, 2011 - Wiley Online Library
P Krejbich‐Trotot, M Denizot, JJ Hoarau, MC Jaffar‐Bandjee, T Das, P Gasque
The FASEB Journal, 2011Wiley Online Library
Chikungunya virus (CHIKV) surprised medical workers by a massive outbreak in the Indian
Ocean region, reaching Europe in 2007, with exceptional pathologies in infants and elderly
patients. Although CHIKV was recently shown to persist in myo‐blasts, monocytes, and
macrophages, we argued that robust antiviral mechanisms, including apoptosis, are
essential to ward off the virus. Herein, we tested the capacity of CHIKVto mobilize the
apoptotic machinery in HeLa cells as well as primary fibroblasts, making use of several …
Chikungunya virus (CHIKV) surprised medical workers by a massive outbreak in the Indian Ocean region, reaching Europe in 2007, with exceptional pathologies in infants and elderly patients. Although CHIKV was recently shown to persist in myo‐blasts, monocytes, and macrophages, we argued that robust antiviral mechanisms, including apoptosis, are essential to ward off the virus. Herein, we tested the capacity of CHIKVto mobilize the apoptotic machinery in HeLa cells as well as primary fibroblasts, making use of several inhibitors of caspases, cell blebbing, and engulfment of the apoptotic blebs by neighboring cells. CHIKV triggered apoptosis through intrinsic and extrinsic pathways. Bystander apoptosis was also evidenced in neighboring cells in a caspase‐8‐dependent manner. Remarkably, by hiding in apoptotic blebs, CHIKV was able to infect neighboring cells. In HeLa cells, these events were inhibited specifically by zVAD‐fmk and DEVD‐cho (caspase inhibitors), blebbistatin, Y‐27632 (ROCK inhibitor), and genistein, annexin V, and cytochalasin B (inhibitors of blebbing and engulf‐ment). These CHIKV‐apoptotic blebs were also capable of infecting macrophages (primary cultures, MM6‐ and THP1‐PMA differentiated cells) otherwise refractory to infection by CHIKV alone. Remarkably, viral replication in macrophages did not yield a proinflammatory response. We describe a novel infectious mechanism by which CHIKV invades host cells and escapes the host response.—Krejbich‐Trotot, P., Denizot, M., Hoarau, J.‐J., Jaffar‐Bandjee, M.‐C., Das, T., Gasque, P. Chikun‐gunya virus mobilizes the apoptotic machinery to invade host cell defenses. FASEB J. 25, 314–325 (2011). www.fasebj.org
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