T cell immunoglobulin- and mucin-domain-containing molecule-4 attenuates concanavalin A-induced hepatitis by regulating macrophage

J Leukoc Biol. 2010 Aug;88(2):329-36. doi: 10.1189/jlb.1209797. Epub 2010 May 7.

Abstract

Tim-4 is expressed primarily on APCs, including macrophages, and has been shown to play a critical role in T cell regulation. However, it remains unclear whether Tim-4 also plays a role in the regulation of macrophage functions. In the present study, we investigated the effects of Tim-4 on macrophage activity in Con A-induced hepatitis in mice. We found that high levels of Tim-4 expression were associated with a diminished serum level of ALT in Con A-induced hepatitis. In addition, adoptive transfer of T4-RAW cells resulted in a significant decrease in ALT levels and Con A-induced liver injuries in mice. Concurrently, T4-RAW cells transfer displayed, markedly decreased apoptosis in liver and depressed TNF-alpha secretion in serum, supporting the hypothesis that Tim-4 protects Con A-induced hepatitis by negatively regulating macrophages. Consistent with the in vivo findings, in vitro studies showed that Tim-4 overexpression in RAW264.7 cells was associated with decreased expression of CD80, CD86, and MHCII molecules and the production of TNF-alpha. Moreover, Tim-4 blockade promoted LPS-induced macrophage activation. In conclusion, these findings indicate that Tim-4 plays an important role in alleviating liver damage by inhibition of macrophage activity. Tim-4 pathway could be a potential target for the treatment of acute hepatitis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • B7-1 Antigen / genetics
  • B7-2 Antigen / genetics
  • Cell Line
  • Concanavalin A / toxicity
  • Down-Regulation / genetics
  • Hepatitis* / immunology
  • Hepatitis* / metabolism
  • Histocompatibility Antigens Class II / genetics
  • Interferon-gamma / genetics
  • Macrophage Activation*
  • Macrophages
  • Male
  • Membrane Proteins / physiology*
  • Mice
  • Mice, Inbred BALB C

Substances

  • B7-1 Antigen
  • B7-2 Antigen
  • Histocompatibility Antigens Class II
  • Membrane Proteins
  • TIM-4 protein, mouse
  • Concanavalin A
  • Interferon-gamma