Differential Ly49e expression pathways in resting versus TCR-activated intraepithelial γδ T cells

J Immunol. 2013 Mar 1;190(5):1982-90. doi: 10.4049/jimmunol.1200354. Epub 2013 Jan 21.

Abstract

The Ly49 NK receptor family in mice is composed of several members that recognize MHC class I (MHC-I) or MHC-I-related molecules. We and others have shown before that Ly49E is a unique member, with a different expression pattern on NK cells and being triggered by the non-MHC-I-related protein urokinase plasminogen activator. Among the entire Ly49 receptor family, Ly49E is the only Ly49 member expressed by epidermal-localized γδ T cells and their fetal thymic TCRγδ precursors, and it is the most abundantly expressed member on intestinal intraepithelial γδ T cell lymphocytes. In this study, we provide mechanistic insights into the regulation of Ly49e expression in γδ T cells. First, we demonstrate that TCR-mediated activation of intraepithelial γδ T cells significantly increases Ly49E expression. This results from de novo Ly49E expression and is highly selective, because no other Ly49 family members are induced. TCR-mediated Ly49E induction is a conserved feature of skin- and gut-residing intraepithelial-localized γδ T cell subsets, whereas it is not observed in spleen γδ T cells. By investigating Ly49e promoter activities and lymphotoxin (LT) αβ dependency in resting versus TCR-activated intraepithelial γδ T cells, we reveal two separate regulatory pathways for Ly49E expression, as follows: a LTαβ-dependent pathway leading to basal Ly49E expression in resting cells that is induced by Pro2-mediated Ly49e transcription, and a LTαβ-independent pathway leading to elevated, Pro3-driven Ly49E expression in TCR-stimulated cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Epidermal Cells
  • Epidermis / drug effects
  • Epidermis / immunology
  • Epithelium / drug effects*
  • Epithelium / immunology
  • Gene Expression Regulation
  • Intestines / cytology
  • Intestines / drug effects
  • Intestines / immunology
  • Killer Cells, Natural / cytology
  • Killer Cells, Natural / drug effects*
  • Killer Cells, Natural / immunology
  • Lymphocyte Activation / drug effects
  • Lymphocyte Activation / immunology
  • Lymphotoxin alpha1, beta2 Heterotrimer / pharmacology
  • Mice
  • Mice, Transgenic
  • NK Cell Lectin-Like Receptor Subfamily A / genetics*
  • NK Cell Lectin-Like Receptor Subfamily A / immunology
  • Promoter Regions, Genetic
  • Receptors, Antigen, T-Cell, gamma-delta / genetics
  • Receptors, Antigen, T-Cell, gamma-delta / immunology*
  • Signal Transduction / drug effects
  • T-Lymphocytes / cytology
  • T-Lymphocytes / drug effects*
  • T-Lymphocytes / immunology
  • Transcription, Genetic / drug effects*
  • Urokinase-Type Plasminogen Activator / pharmacology

Substances

  • Lymphotoxin alpha1, beta2 Heterotrimer
  • NK Cell Lectin-Like Receptor Subfamily A
  • Receptors, Antigen, T-Cell, gamma-delta
  • Urokinase-Type Plasminogen Activator