IJMS, Vol. 19, Pages 1446: Sphingosine-1-Phosphate Receptor 1 Is Involved in Non-Obese Diabetic Mouse Thymocyte Migration Disorders (International Journal of Molecular Sciences)

NOD (non-obese diabetic) mice spontaneously develop type 1 diabetes following T cell-dependent destruction of pancreatic β cells. Several alterations are observed in the NOD thymus, including the presence of giant perivascular spaces (PVS) filled with single-positive (SP) CD4+ and CD8+ T cells that accumulate in the organ. These cells have a decreased expression of membrane CD49e (the α5 integrin chain of the fibronectin receptor VLA-5 (very late antigen-5). Herein, we observed lower sphingosine-1-phosphate receptor 1 (S1P1) expression in NOD mouse thymocytes when compared with controls, mainly in the mature SP CD4+CD62Lhi and CD8+CD62Lhi subpopulations bearing the CD49e− phenotype. In contrast, differences in S1P1 expression were not observed in mature CD49e+ thymocytes. Functionally, NOD CD49e− thymocytes had reduced S1P-driven migratory response, whereas CD49e+ cells were more responsive to S1P. We further noticed a decreased expression of the sphingosine-1-phosphate lyase (SGPL1) in NOD SP thymocytes, which can lead to a higher sphingosine-1-phosphate (S1P) expression around PVS and S1P1 internalization. In description, our results indicate that the modulation of S1P1 expression and S1P/S1P1 interactions in NOD mouse thymocytes are part of the T-cell migratory disorder observed during the pathogenesis of type 1 diabetes.