Aquaporin 4 inhibition alters chemokine receptor expression and T cell trafficking

Sci Rep. 2019 May 15;9(1):7417. doi: 10.1038/s41598-019-43884-2.

Abstract

Aquaporins (AQPs) are water channels that mediate a variety of biological processes. However, their role in the immune system is poorly understood. We recently reported that AQP4 is expressed by naïve and memory T cells and that AQP4 blockade with a small molecule inhibitor prolongs murine heart allograft survival at least partially through diminishing T cell activation, proliferation and trafficking. The goal of this study was to determine how AQP4 function impacts T cells in the absence of antigen stimulation. AQP4 inhibition transiently reduced the number of circulating CD4+ and CD8+ T cells in naïve non-transplanted mice in the absence of systemic T cell depletion. Adoptive transfer studies demonstrated T cell intrinsic effect of AQP4 inhibition. AQP4 blockade altered T cell gene and protein expression of chemokine receptors S1PR1 and CCR7, and their master regulator KLF-2, and reduced chemotaxis toward S1P and CCL21. Consistent with the in vitro data, in vivo AQP4 inhibition reduced T lymphocyte numbers in the lymph nodes with simultaneous accumulation in the liver. Our findings indicate that blocking AQP4 reversibly alters T lymphocyte trafficking pattern. This information can be explored for the treatment of undesirable immune responses in transplant recipients or in patients with autoimmune diseases.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Aquaporin 4 / antagonists & inhibitors*
  • Aquaporin 4 / metabolism
  • Chemotaxis
  • Female
  • Flow Cytometry
  • Heart Transplantation
  • Lymphocyte Activation
  • Lymphocyte Count
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Osmotic Pressure
  • Real-Time Polymerase Chain Reaction
  • Receptors, CCR7 / metabolism*
  • Sphingosine-1-Phosphate Receptors / metabolism*
  • T-Lymphocytes / metabolism
  • T-Lymphocytes / physiology*

Substances

  • Aqp4 protein, mouse
  • Aquaporin 4
  • Ccr7 protein, mouse
  • Receptors, CCR7
  • S1pr1 protein, mouse
  • Sphingosine-1-Phosphate Receptors