Sphingosine 1-phosphate potentiates human lung fibroblast chemotaxis through the S1P2 receptor.
Migration of fibroblasts plays an essential role in tissue repair after injury. Sphingosine 1-phosphate (S1P) is a multifunctional mediator released by many cells that can be released in inflammation and after injury. This study evaluated the effect of S1P on fibroblast chemotaxis toward fibronectin. S1P alone did not affect fibroblast migration, but S1P enhanced fibronectin-directed chemotaxis in a concentration-dependent manner. The effect of S1P was not mimicked by dihydro (dh) S1P or the S1P(1) receptor agonist SEW2871. S1P augmentation of fibroblast chemotaxis, however, was completely blocked by JTE-013, an S1P(2) antagonist, but not by suramin, an S1P(3) antagonist. Suppression of the S1P(2) receptor by small interfering (si)RNA also completely blocked S1P augmentation of fibroblast chemotaxis to fibronectin. S1P stimulated Rho activation and focal adhesion kinase (FAK) phosphorylation, and these were also significantly inhibited by the S1P(2) receptor antagonist (JTE-013) or by S1P(2) siRNA. Further, the potentiation of S1P signaling was blocked by the Rho-kinase inhibitor Y-27632 in a concentration-dependent manner. Inhibition of FAK with siRNA reduced basal chemotaxis toward fibronectin slightly but significantly, and almost completely blocked S1P augmented chemotaxis. These results suggest that S1P-augmented fibroblast chemotaxis toward fibronectin depends on the S1P(2) receptor and requires Rho and Rho-kinase, and FAK phosphorylation. By augmenting fibroblast recruitment, S1P has the potential to modulate tissue repair after injury. The pathways by which S1P mediates this effect, therefore, represent a potential therapeutic target to affect tissue repair and remodeling.
Hashimoto
Mitsu
M
Department of Pathology, Nagoya University School of Medicine, Nagoya, Japan.
Wang
Xingqi
X
Mao
Lijun
L
Kobayashi
Tetsu
T
Kawasaki
Shin
S
Mori
Naoyoshi
N
Toews
Myron L
ML
Kim
Hui Jung
HJ
Cerutis
D Roselyn
DR
Liu
Xiangde
X
Rennard
Stephen I
SI
D001483:Base Sequence; D015153:Blotting, Western; D002478:Cells, Cultured; D002633:Chemotaxis; D017931:DNA Primers; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D005353:Fibronectins / Q000494:pharmacology; D006801:Humans; D047468:Immunoprecipitation; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008246:Lysophospholipids / Q000494:pharmacology / Q000502:physiology*; D034622:RNA Interference; D049349:Receptors, Lysosphingolipid / Q000502:physiology*; D012038:Regeneration / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000502:physiology
D017931:DNA Primers; D005353:Fibronectins; D008246:Lysophospholipids; D049349:Receptors, Lysosphingolipid; C060506:sphingosine 1-phosphate; D013110:Sphingosine