The BMP Pathway Participates in Human Naive CD4+ T Cell Activation and Homeostasis

PLoS One. 2015 Jun 25;10(6):e0131453. doi: 10.1371/journal.pone.0131453. eCollection 2015.

Abstract

Bone Morphogenetic Proteins (BMPs) form a group of secreted factors that belongs to the TGF-β superfamily. Among different roles in a number of immune cell types, BMPs are known to regulate T cell development within the thymus, although the role of BMP signaling in human mature T cells remains elusive. In this study, we demonstrate that canonical BMP signaling is necessary during two critical events that regulate the size and function of human naive CD4+ T cell population: activation and homeostasis. Upon stimulation via TCR, naive CD4+ T cells upregulate the expression of BMP ligands triggering canonical BMP signaling in CD25+ cells. Blockade of BMP signaling severely impairs CD4+ T cell proliferation after activation mainly through regulation of IL-2, since the addition of this cytokine recuperates normal T cell expansion after inhibition of BMP signaling. Similarly, activation of canonical BMP pathway is required for both the maintenance of cell survival and the homeostatic proliferation induced by IL-7, a key factor for T cell homeostasis. Moreover, upregulation of two critical receptors for T cell homeostasis, CXCR4 and CCR9, triggered by IL-7 is also abrogated in the absence of BMP signaling. Collectively, we describe important roles of the canonical BMP signaling in human naive CD4+ T cell activation and homeostasis that could be valuable for clinical application.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activin Receptors, Type II / metabolism
  • Apoptosis / immunology
  • Bone Morphogenetic Protein Receptors, Type I / metabolism
  • Bone Morphogenetic Proteins / metabolism*
  • CD4-Positive T-Lymphocytes / cytology
  • CD4-Positive T-Lymphocytes / immunology*
  • Cell Differentiation / immunology*
  • Cell Proliferation
  • Cells, Cultured
  • Gene Expression Regulation
  • Humans
  • Interleukin-2 / metabolism
  • Interleukin-7 / metabolism
  • Lymphocyte Activation / immunology*

Substances

  • Bone Morphogenetic Proteins
  • IL2 protein, human
  • IL7 protein, human
  • Interleukin-2
  • Interleukin-7
  • ACVRL1 protein, human
  • Activin Receptors, Type II
  • Bone Morphogenetic Protein Receptors, Type I

Grants and funding

This work was supported by grants SAF2012-33180 (Ministerio de Economía y Competitividad), S2010/BMD-2420 (Comunidad de Madrid) and RD12/0019/0007 (Instituto de Salud Carlos III). L.H. is supported by pre-doctoral fellowships (AP2009-4324) from the Ministerio de Educación, Cultura y Deporte.