Kaposi's sarcoma-associated herpesvirus-encoded latency-associated nuclear antigen reduces interleukin-8 expression in endothelial cells and impairs neutrophil chemotaxis by degrading nuclear p65

J Virol. 2011 Sep;85(17):8606-15. doi: 10.1128/JVI.00733-11. Epub 2011 Jun 22.

Abstract

Latency-associated nuclear antigen 1 (LANA-1) of Kaposi's sarcoma-associated herpesvirus (KSHV) is the major viral latent protein and functions as a multifaceted protein. Here, we report that LANA-1 attenuates the endothelial response to tumor necrosis factor alpha (TNF-α) stimulation and inhibits consequent neutrophil chemotaxis. Reporter assays showed that LANA-1 constantly repressed nuclear factor (NF)-κB transactivity upon TNF-α stimulation. We also found that LANA-1 decreased nuclear p65 protein levels through enhancement of polyubiquitylation-mediated p65 degradation and that an elongin B/elongin C-cullin 5-LANA-1-p65 complex assembled by LANA-1 was responsible for this enhanced p65 degradation. In telomerase-immortalized human umbilical vein endothelial cells, LANA-1 was demonstrated to repress interleukin-8 expression, which was involved in neutrophil recruitment to the inflammatory site. Through an in vitro transmigration assay, we determined a suppressive effect of LANA-1 on neutrophil chemotaxis. Our work suggests that KSHV LANA-1 is a negative modulator of acute inflammation and sheds light on a new mechanism by which KSHV during the latent life cycle evades the host innate immune response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Viral / immunology
  • Antigens, Viral / metabolism*
  • Cell Line
  • Cell Migration Assays, Leukocyte
  • Cell Movement
  • Endothelial Cells / virology*
  • Genes, Reporter
  • Herpesvirus 8, Human / immunology
  • Herpesvirus 8, Human / pathogenicity*
  • Host-Pathogen Interactions*
  • Humans
  • Immune Evasion
  • Interleukin-8 / antagonists & inhibitors*
  • Neutrophils / immunology*
  • Nuclear Proteins / immunology
  • Nuclear Proteins / metabolism*
  • Transcription Factor RelA / antagonists & inhibitors*
  • Tumor Necrosis Factor-alpha / immunology

Substances

  • Antigens, Viral
  • CXCL8 protein, human
  • Interleukin-8
  • Nuclear Proteins
  • RELA protein, human
  • Transcription Factor RelA
  • Tumor Necrosis Factor-alpha
  • latency-associated nuclear antigen