Notch signaling is required for proliferation but not for differentiation at a well-defined beta-selection checkpoint during human T-cell development

Blood. 2009 Apr 2;113(14):3254-63. doi: 10.1182/blood-2008-07-168906. Epub 2008 Oct 23.

Abstract

Notch signaling is absolutely required for beta-selection during mouse T-cell development, both for differentiation and proliferation. In this report, we investigated whether Notch has an equally important role during human T-cell development. We show that human CD34(+) thymocytes can differentiate into CD4(+)CD8beta(+) double positive (DP) thymocytes in the absence of Notch signaling. While these DP cells phenotypically resemble human beta-selected cells, they lack a T-cell receptor (TCR)-beta chain. Therefore, we characterized the beta-selection checkpoint in human T-cell development, using CD28 as a differential marker at the immature single positive CD4(+)CD3(-)CD8alpha(-) stage. Through intracellular TCR-beta staining and gene expression analysis, we show that CD4(+)CD3(-)CD8alpha(-)CD28(+) thymocytes have passed the beta-selection checkpoint, in contrast to CD4(+)CD3(-)CD8alpha(-)CD28(-) cells. These CD4(+)CD3(-)CD8alpha(-)CD28(+) thymocytes can efficiently differentiate into CD3(+)TCRalphabeta(+) human T cells in the absence of Notch signaling. Importantly, preselection CD4(+)CD3(-)CD8alpha(-)CD28(-) thymocytes can also differentiate into CD3(+)TCRalphabeta(+) human T cells without Notch activation when provided with a rearranged TCR-beta chain. Proliferation of human thymocytes, however, is clearly Notch-dependent. Thus, we have characterized the beta-selection checkpoint during human T-cell development and show that human thymocytes require Notch signaling for proliferation but not for differentiation at this stage of development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD34 / metabolism
  • CD28 Antigens / metabolism
  • CD4 Antigens / metabolism
  • CD8 Antigens / metabolism
  • Cell Differentiation / genetics
  • Cell Differentiation / immunology
  • Cell Proliferation*
  • Cells, Cultured
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology
  • Gene Rearrangement, beta-Chain T-Cell Antigen Receptor* / physiology
  • Genes, Dominant / physiology
  • Genes, T-Cell Receptor beta / physiology*
  • Humans
  • Models, Biological
  • Receptors, Notch / genetics
  • Receptors, Notch / physiology*
  • Signal Transduction / genetics
  • Signal Transduction / physiology
  • T-Lymphocytes / metabolism
  • T-Lymphocytes / physiology*
  • Thymus Gland / cytology
  • Thymus Gland / metabolism
  • Thymus Gland / physiology
  • Trans-Activators / genetics
  • Trans-Activators / physiology
  • Transcription Factors

Substances

  • Antigens, CD34
  • CD28 Antigens
  • CD4 Antigens
  • CD8 Antigens
  • DNA-Binding Proteins
  • MAML1 protein, human
  • Receptors, Notch
  • Trans-Activators
  • Transcription Factors