γδ T Cells Exacerbate Podocyte Injury via the CD28/B7-1-Phosphor-SRC Kinase Pathway

Biomed Res Int. 2018 May 15:2018:5647120. doi: 10.1155/2018/5647120. eCollection 2018.

Abstract

Primary nephrotic syndrome (PNS) is a devastating pediatric disorder. However, its mechanism remains unclear. Previous studies detected B7-1 in podocytes; meanwhile, γδT cells play pivotal roles in immune diseases. Therefore, this study aimed to assess whether and how γδT cells impact podocytes via the CD28/B7-1 pathway. WT and TCRδ-/- mice were assessed. LPS was used to induce nephropathy. Total γδT and CD28+γδT cells were quantitated in mouse spleen and kidney samples. B7-1 and phosphor-SRC levels in the kidney were detected as well. In vitro, γδT cells from the mouse spleen were cocultured with mouse podocytes, and apoptosis rate and phosphor-SRC expression in podocytes were assessed. Compared with control mice, WT mice with LPS nephropathy showed increased amounts of γδT cells in the kidney. Kidney injury was alleviated in TCRδ-/- mice. Meanwhile, B7-1 and phosphor-SRC levels were increased in the kidney from WT mice with LPS nephropathy. CD28+γδT cells were decreased, indicating CD28 may play a role in LPS nephropathy. Immunofluorescence colocalization analysis revealed a tight association of γδT cells with B7-1 in the kidney. High B7-1 expression was detected in podocytes treated with LPS. Podocytes cocultured with γδT cells showed higher phosphor-SRC and apoptosis rate than other cell groups. Furthermore, CD28/B7-1 blockage with CTLA4-Ig in vitro relieved podocyte injury. γδT cells exacerbate podocyte injury via CD28/B7-1 signaling, with downstream involvement of phosphor-SRC. The CD28/B7-1 blocker CTLA4-Ig prevented progressive podocyte injury, providing a potential therapeutic tool for PNS.

MeSH terms

  • Animals
  • B7-1 Antigen / immunology*
  • CD28 Antigens / immunology*
  • Female
  • Mice
  • Nephrotic Syndrome / immunology*
  • Nephrotic Syndrome / pathology
  • Podocytes / immunology*
  • Podocytes / pathology
  • Receptors, Antigen, T-Cell, gamma-delta / immunology*
  • Signal Transduction / immunology*
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / pathology
  • src-Family Kinases / immunology*

Substances

  • B7-1 Antigen
  • CD28 Antigens
  • Receptors, Antigen, T-Cell, gamma-delta
  • src-Family Kinases