Sphingosine 1-Phosphate Potentiates Human Lung Fibroblast Chemotaxis through the S1P₂ Receptor

Abstract

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 concentrationdependent 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.

Prolonged Exposure to Sphingosine 1–Phosphate Receptor-1 Agonists Exacerbates Vascular Leak, Fibrosis, and Mortality after Lung Injury

“…Nevertheless, we cannot exclude the possibility that the increased overall inflammatory response or reduction in BAL T cells we observed with prolonged S1P 1 agonist treatment may have contributed to the exaggerated fibrotic response to lowdose bleomycin. S1P can also mediate other processes that may contribute to the development of lung fibrosis, including cellular apoptosis, fibroblast chemotaxis, angiogenesis, and TGF-b signaling (7,(67)(68)(69)(70)(71)(72)(73)(74)(75)(76)(77)(78). Therefore, further elucidation of the effects of S1P 1 agonists on these biological processes will be of interest for a better understanding of how S1P-S1P 1 signaling modifies the fibrotic response to injury.…”

Prostaglandin E2Inhibits Human Lung Fibroblast Chemotaxis through Disparate Actions on Different E-Prostanoid Receptors

“…This study explored the role of the EP1, EP2, EP3, and EP4 receptors in modulating human lung fibroblast migration, using the blindwell chemotaxis assay and a woundclosure assay. Table 1 summarizes the pharmacologic compounds used in this study, and describes their specificity (9,(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34). PGE 2 was purchased from Sigma (St. Louis, MO) and was dissolved in 100% ethanol as a stock solution of 10 23 M, and further diluted in medium to the designated concentrations.…”

Sphingosine-1-Phosphate Modulates Vascular Permeability and Cell Recruitment in Acute Inflammation In Vivo

“…It is known that the chemotactic action of S1P relies on receptor interaction Hashimoto et al, 2008;Ishii et al, 2009;Harvey et al, 2010;Thangada et al, 2010). S1P 2 and S1P 3 antagonists significantly inhibited in vivo zymosaninduced neutrophil accumulation.…”

“…L-Cycloserine significantly reduced cell adhesion and emigration, whereas DTD did not significantly affect both cell adhesion and emigration. S1P has chemotactic activity Hashimoto et al, 2008;Ishii et al, 2009;Harvey et al 2010;Thangada et al, 2010). To clarify whether this effect on adhesion and migration was mediated by chemotactic action of S1P on inflammatory cells, we used the mouse air pouch, a preclinical experimental model that allows evaluating chemotaxis in vivo.…”