Nussbaum, Claudia and Levkau, Bodo (2015) Sphingosine1phosphate receptor 3 promotes leukocyte rolling by mobilizing endothelial Pselectin. Nat Commun, 6. p. 6416. ISSN 2041-1723

Abstract

Sphingosine‐1‐phosphate (S1P) plays important roles in immunity and inflammation.
We have previously shown that the S1P receptor S1P3 promotes inflammatory cell
recruitment in atherosclerosis. Here, we have examined whether S1P affects the rapid,
within minutes occurring P‐selectin‐dependent leukocyte rolling – the initial step in
leukocyte recruitment. Using intravital microscopy in the mouse cremaster muscle we
observed that rolling was dramatically reduced in S1P3‐/‐ mice. Application of the S1P3
inhibitor TY‐52156 reduced rolling in wild type mice, while intra‐arterial application of
genuine S1P increased rolling further. In human endothelial cells, stimulation with S1P
led to rapid P‐selectin mobilization to the cell surface that was mediated by S1P3 and
conveyed by a pathway involving Gαq, PLCß and Ca2+. Accordingly, rolling was lower in
mice deficient for Gαq in endothelial cells but did not decrease any further with S1P3
inhibition. Furthermore, S1P3 contributed to full‐scale P‐selectin‐mobilization by other
agents such as histamine and epinephrine by activating sphingosine kinase 1 (Sphk1)
and S1P production that engaged S1P3 as shown by Sphk1 and S1P3 inhibition, C17‐S1P
generation and the compromised rolling in Sphk1‐/‐ mice. In agreement with a role for
cAMP in Sphk1 activation, forskolin and cpt‐cAMP induced P‐selectin mobilization in
vitro, and forskolin enhanced leukocyte rolling in vivo. Treatment with FTY720 or S1P
lyase inhibition attenuated both leukocyte rolling and P‐selectin mobilization but had no
further effect in S1P3‐/‐ mice in agreement with a S1P3‐dependent mode of action. In
contrast, rolling was increased in mice deficient for endothelial S1P1, where FTY720 also
reduced rolling to the same low levels as in S1P3‐/‐ mice with and without FTY720. As
mast cell activation products released after mechanical trauma are the causal effectors
of leukocyte rolling in this model, we tested whether they release S1P after physical
manipulation in vitro. Indeed, S1P was released by mast cells and mobilized P‐selectin in
endothelial cells in a S1P3‐dependent manner. In summary, acute S1P release promoted
directly P‐selectin‐dependent leukocyte rolling and contributed indirectly to full‐scale Pselectin
mobilization capacity to other P‐selectin agonists via Sphk1/S1P3. While
engaging both endothelial S1P1 and S1P3, the net effect of S1P was determined by the
dominant pro‐rolling action of its S1P3 receptor.

Item Type:	Article
Date Deposited:	26 Apr 2016 23:45
Last Modified:	26 Apr 2016 23:45
URI:	https://oak.novartis.com/id/eprint/24524