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Molecular Mechanism of Tethers and Slings in CD4 + T cells
Author(s) -
Abadier Michael,
Ley Klaus
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.723.3
Subject(s) - chemistry , flow cytometry , microbiology and biotechnology , t cell , cell , shear stress , immunology , biophysics , biology , materials science , immune system , biochemistry , composite material
Leukocyte recruitment towards the site of injury is a tightly regulated multi‐step process initiated by rolling along the luminal surface of inflamed endothelium in the presence of high shear flow. The interaction of endothelial P‐selectin‐to‐P‐selectin glycoprotein ligand (PSGL)‐1 constitutively expressed in leukocytes mediates leukocyte rolling by rapid formation and breakage of selectin‐to‐ligand bonds to balance the hydrodynamic drag forces exerted by blood shear stress. Once pulling forces due to the high shear exceed a critical threshold, tethers and slings become essential to support leukocyte rolling. Slings, recently discovered by our group, are long cell adhesive structures derived from long tethers. Here, we polarized naïve T cells towards distinct lineages of CD4 + effector T cells (Th1, Th2, Th17 and Treg). Considering the critical role of functional PSGL‐1 for T cell rolling, we tested functional PSGL‐1 by P‐selectin‐Fc binding in flow cytometry. PSGL‐1 in Th1, Th17 and Treg is functional in 70–80% of cells, but only in 10–20% of Th2 cells and 0% of Naïve CD4 T cells. To visualize the dynamic process of T cell rolling, we performed live cell imaging under high shear stress (>5 dyn/cm 2 ). Interestingly, the rolling speed of Th2 cells was significantly higher when compared to the other T cell subsets. This was mirrored by observing tethers and slings in Th1, Th17, Treg but to a lesser extent in Th2. Surprisingly, some of the few Th1 or Th17 cells bearing non‐functional PSGL‐1 were able to form tethers and slings, suggesting that functional PSGL‐1 binding to P‐selectin allows for T cell rolling at reduced speed but might not be the sole requirement for tether and sling formation. To identify the molecular and cellular requirements for tether and sling formation, Naïve CD4 + T cells and neutrophils will be used as negative and positive controls, respectively. By developing gene expression maps we will identify the differentially regulated genes during T cell lineage differentiation. Upregulated genes in Th1, Th17 and Treg, but not in Th2, are excellent candidates for being involved in tether and sling formation. Support or Funding Information Swiss National Science Foundation and P01 HL078784/NIH