Differential Regulation of Airway Smooth Muscle Cell Migration by E-Prostanoid Receptor Subtypes

Abstract

Migration of airway smooth muscle (ASM) cells plays an important role in the pathophysiology of airway hyperresponsiveness and remodeling in asthma. It has been reported that prostaglandin (PG)E2 inhibits migration of ASM cells. Although PGE2 regulates cellular functions via binding to distinct prostanoid EP receptors, the role of EP receptor subtypes in mechanisms underlying cell migration has not been fully elucidated. We investigated the role of EP receptors in the inhibitory effects of PGE2 on the migration of human ASM cells. Migration induced by platelet-derived growth factor (PDGF)-BB (10 ng/ml, 6 h) was assessed by a chemotaxis chamber assay. PDGF-BB-induced cell migration was inhibited by PGE2, the specific EP2 agonist ONO-AE1-259-01, the specific EP4 agonist ONO-AE1-329, and cAMP-mobilizing agents. The inhibition of cell migration by PGE2 was significantly reversed by a blockade of EP2 and EP4 receptors using antagonists or transfection with siRNAs. Moreover, PGE2, the EP2 agonist, and the EP4 agonist significantly increased phosphorylation of small heat shock protein 20, one of the protein substrates for protein kinase A (PKA), with depolymerization of actin. In contrast, the EP3 agonist ONO-AE-248 significantly promoted baseline cell migration without affecting PDGF-BB-induced cell migration. In summary, activation of EP2 and EP4 receptors and subsequent activation of the cAMP/PKA pathway are the main mechanisms of inhibition of ASM cell migration by PGE2. HSP20 phosphorylation by PKA is possibly involved in this mechanism. Conversely, EP3 is potent in promoting cell migration. EP receptor subtypes may be novel therapeutic target molecules in airway remodeling and asthma.

Cooperativity of E‐prostanoid receptor subtypes in regulating signaling and growth inhibition in human airway smooth muscle

“…G s -coupled EP receptors on HASM are particularly attractive targets for asthma treatment, given we and others have demonstrated an ability (superior to that of b-agonists) of PGE 2 to both relax contracted HASM and inhibit mitogenstimulated HASM proliferation (14). These G s -, cAMP-, and PKA-dependent effects occur despite a demonstrated counteracting effect of EP3 receptor signaling in HASM (14,28). Efforts to limit the side effects of PGE 2 by developing subtype-selective EP ligands have, until recently, been disappointing.…”

Cyclooxygenase-2–Derived Prostaglandin E 2 Promotes Injury-Induced Vascular Neointimal Hyperplasia Through the E-prostanoid 3 Receptor

“…Pharmacological inhibition, gene silencing using siRNA, or genetic deletion of the EP3 receptor retarded PGE 2 -induced VSMC migration, indicating that COX-2-derived PGE 2 mediated VSMC migration through EP3 α/β activation (Figure 2). Recently, EP3 was to shown to promote the migration of other cells such as airway smooth muscle cells 34 . Deficiency of EP3 attenuated the thickening of the neointima, while over-expression of EP3α or EP3β in vasculature augmented its formation in mice, which suggests that EP3-mediated VSMC migration contributes to the vascular remodeling in response to mechanical injury.…”

CXCL1 Inhibits Airway Smooth Muscle Cell Migration through the Decoy Receptor Duffy Antigen Receptor for Chemokines

“…Directed cell migration, also known as chemotaxis, is a complex process initiated by a concentration gradient of stimulus sensed by specific receptors, followed by activation of signaling pathways, cellular polarization, recycling of actin filaments and actin binding proteins, and recruitment of cell-cell and cell-matrix adhesion proteins (50,51). There has been little progress in understanding the underlying mechanisms driving cell migration, and there are few examples of molecules capable of its inhibition (52,53). In this study, we demonstrate that CXCL1 is a physiologically significant inhibitor of both basal and stimulated ASMC migration.…”