HCV genomic RNA activates the NLRP3 inflammasome in human myeloid cells

PLoS One. 2014 Jan 6;9(1):e84953. doi: 10.1371/journal.pone.0084953. eCollection 2014.

Abstract

Background: Elevated plasma levels of IL-1β and IL-18 from patients with hepatitis C virus (HCV) infection indicate a possible activation of inflammasome by HCV.

Methodology/principal findings: To demonstrate whether HCV infection activates the inflammasome, we investigated inflammasome activation from HCV infected hepatic Huh7 cells, or monocytic cells and THP-1 derived macrophages challenged with HCV virions, but no any inflammasome activation was detected in these cells. However, when we transfected HCV genomic RNA into monocytes or macrophages, IL-1β was secreted in a dose-dependent manner. We also detected ASC oligomerization and caspase-1 cleavage in HCV RNA transfected macrophages. Using shRNA-mediated gene silencing or specific inhibitors, we found that HCV RNA-induced IL-1β secretion was dependent on the presence of inflammasome components such as NLRP3, ASC and caspase-1. Furthermore, we also found that RIG-I was dispensable for HCV RNA-induced NLRP3 inflammasome activation, while reactive oxygen species (ROS) production was required.

Conclusions: Our results indicate that HCV RNA activates the NLRP3 inflammasome in a ROS-dependent manner, and RIG-I is not required for this process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carrier Proteins / metabolism*
  • Cell Line
  • DEAD Box Protein 58
  • DEAD-box RNA Helicases / metabolism
  • Genome, Viral*
  • Hepacivirus / genetics*
  • Hepatitis C / metabolism*
  • Hepatitis C / virology
  • Humans
  • Inflammasomes*
  • Interleukin-1beta / biosynthesis
  • Macrophages / metabolism
  • Macrophages / virology
  • Monocytes / metabolism
  • Monocytes / virology
  • Myeloid Cells / metabolism*
  • Myeloid Cells / virology*
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • RNA, Viral*
  • Reactive Oxygen Species / metabolism
  • Receptors, Immunologic

Substances

  • Carrier Proteins
  • Inflammasomes
  • Interleukin-1beta
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • NLRP3 protein, human
  • RNA, Viral
  • Reactive Oxygen Species
  • Receptors, Immunologic
  • RIGI protein, human
  • DEAD Box Protein 58
  • DEAD-box RNA Helicases

Grants and funding

This work was supported by grants from 100 Talent Program of the Chinese Academy of Sciences, Natural Science Foundation of China (91029707, 31170868), Novo Nordisk-CAS Research Foundation, SA-SIBS Scholarship Program, as well as grants from the National Key Programs on Infectious Disease (2012ZX10002007-003). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.