Peli1 facilitates virus replication and promotes neuroinflammation during West Nile virus infection
Huanle Luo, … , Patricia V. Aguilar, Tian Wang
Huanle Luo, … , Patricia V. Aguilar, Tian Wang
Published September 24, 2018
Citation Information: J Clin Invest. 2018;128(11):4980-4991. https://doi.org/10.1172/JCI99902.
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Research Article Inflammation Virology

Peli1 facilitates virus replication and promotes neuroinflammation during West Nile virus infection

Abstract

The E3 ubiquitin ligase Pellino 1 (Peli1) is a microglia-specific mediator of autoimmune encephalomyelitis. Its role in neurotropic flavivirus infection is largely unknown. Here, we report that mice deficient in Peli1 (Peli1–/–) were more resistant to lethal West Nile virus (WNV) infection and exhibited reduced viral loads in tissues and attenuated brain inflammation. Peli1 mediates chemokine and proinflammatory cytokine production in microglia and promotes T cell and macrophage infiltration into the CNS. Unexpectedly, Peli1 was required for WNV entry and replication in mouse macrophages and mouse and human neurons and microglia. It was also highly expressed on WNV-infected neurons and adjacent inflammatory cells from postmortem patients who died of acute WNV encephalitis. WNV passaged in Peli1–/– macrophages or neurons induced a lower viral load and impaired activation in WT microglia and thereby reduced lethality in mice. Smaducin-6, which blocks interactions between Peli1 and IRAK1, RIP1, and IKKε, did not inhibit WNV-triggered microglia activation. Collectively, our findings suggest a nonimmune regulatory role for Peli1 in promoting microglia activation during WNV infection and identify a potentially novel host factor for flavivirus cell entry and replication.

Authors

Huanle Luo, Evandro R. Winkelmann, Shuang Zhu, Wenjuan Ru, Elizabeth Mays, Jesus A. Silvas, Lauren L. Vollmer, Junling Gao, Bi-Hung Peng, Nathen E. Bopp, Courtney Cromer, Chao Shan, Guorui Xie, Guangyu Li, Robert Tesh, Vsevolod L. Popov, Pei-Yong Shi, Shao-Cong Sun, Ping Wu, Robyn S. Klein, Shao-Jun Tang, Wenbo Zhang, Patricia V. Aguilar, Tian Wang

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Figure 2

Peli1 facilitates WNV replication in macrophages and promotes high mortality in vivo.

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Peli1 facilitates WNV replication in macrophages and promotes high morta...
(A and B) The viral load of WNV-infected macrophages was measured by qPCR (A) and FFA (B). Data are representative of 5 similar experiments and are presented as the mean ± SEM (n = 3–6). (C and D) Macrophages were infected with WNV for 1 hour at 4°C, washed, and then collected to measure intracellular viral RNA by qPCR in the attachment assay (C). For virus entry (D), cells were subsequently resuspended in medium and incubated at 37°C. At the indicated time points, cells were washed to determine intracellular viral RNA levels (n = 6). (E and F) Thin-section transmission electron micrographs of WNV-infected macrophages. (E) Viral particles were observed at the plasma membrane at 0 minutes, in small, uncoated vesicles at 5 minutes, and in double-membrane vesicles at 10 hours. (F) Quantitation of 10 fields of view of ultrathin sections. (G) Negative staining micrographs of WNV. Virions ranged in size from 41 nm to 47 nm and 23.5 nm to 39.5 nm in supernatants of WT and Peli1–/– macrophages on day 4 p.i., respectively. (H) WT macrophages were infected at a MOI of 0.02 with viruses passaged in WT (WTP) and Peli1–/– (Peli1–/–P) macrophages. The viral load was measured by FFA on day 4 p.i. Data are representative of 2 similar experiments and are presented as the mean ± SEM (n = 4). Data in A–D and H were analyzed by unpaired, 2-tailed Student’s t test. *P < 0.05 and **P < 0.01 compared with the WT group. (I) Survival rates of mice injected i.p. with 100 FFU WNV passaged in WT macrophages and Peli1–/– macrophages (n = 7–9). *P < 0.05 compared with WT mice infected with WT macrophages (log-rank test).