Jie Song , Kang Li , Ting Li , Gaihong Zhao , Shijun Zhou , Huang Li , Jiangnan Li , Changjiang Weng 

J Virol Methods.2020 Aug 19;113958.doi: 10.1016/j.jviromet.2020.113958. Online ahead of print.

Abstract

Inflammasome plays a major role in innate immune responses by activating caspase-1, resulting in secretion of interleukin-1β (IL-1β) and inflammatory pathologic responses. IL-1β release is widely used as an indirect readout to study inflammasome activation. Here we report an iGLuc reporter (pro-IL-1β-Gluc) of pig origin to monitor cytosolic pro-IL-1β cleavage and mature IL-1β release. Based on the iGLuc reporter, we reconstructed the inflammasome system in vitro and screened PRRSV- and ASFV-encoded proteins involved in regulating inflammasome activation. We found that three non-structural proteins (nsps) of PRRSV, nsp1β, nsp2 and nsp5, activate the NLRP3 inflammasome, and four nsps of PRRSV, nsp1ɑ, nsp7, nsp10 and nsp11, inhibit NLRP3 inflammasome activation, of which nsp10 and nsp11 have a highly significant inhibitory effect. In addition, we also found that four ASFV-encoded proteins, S183 L, E199 L, O61R and I7L activate the inflammatory response and four ASFV-encoded proteins, I226 L, A151R, NP419 L and QP383R, inhibit the inflammatory response. Our results provide a highly sensitive and high-throughput tool to screen for proteins that regulate inflammasome activation in vitro.

Keywords: ASFV; IL-1β; PRRSV; iGLuc; inflammasome activation.

Copyright © 2020. Published by Elsevier B.V.