Chronic activation of the prostaglandin receptor EP4 promotes hyaluronan-mediated neointimal formation in the ductus arteriosus
Utako Yokoyama, … , Yukihiko Sugimoto, Yoshihiro Ishikawa
Utako Yokoyama, … , Yukihiko Sugimoto, Yoshihiro Ishikawa
Published November 1, 2006
Citation Information: J Clin Invest. 2006;116(11):3026-3034. https://doi.org/10.1172/JCI28639.
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Research Article Cardiology

Chronic activation of the prostaglandin receptor EP4 promotes hyaluronan-mediated neointimal formation in the ductus arteriosus

Abstract

PGE, a potent vasodilator, plays a primary role in maintaining the patency of the ductus arteriosus (DA). Genetic disruption of the PGE-specific receptor EP4, however, paradoxically results in fatal patent DA (PDA) in mice. Here we demonstrate that EP4-mediated signals promote DA closure by hyaluronic acid–mediated (HA-mediated) intimal cushion formation (ICF). Chronic EP4 stimulation by ONO-AE1-329, a selective EP4 agonist, significantly enhanced migration and HA production in rat DA smooth muscle cells. When HA production was inhibited, EP4-mediated migration was negated. Activation of EP4, adenylyl cyclase, and PKA all increased HA production and the level of HA synthase 2 (HAS2) transcripts. In immature rat DA explants, ICF was promoted by EP4/PKA stimuli. Furthermore, adenovirus-mediated Has2 gene transfer was sufficient to induce ICF in EP4-disrupted DA explants in which the intimal cushion had not formed. Accordingly, signals through EP4 have 2 essential roles in DA development, namely, vascular dilation and ICF. The latter would lead to luminal narrowing, helping adhesive occlusion and permanent closure of the vascular lumen. Our results imply that HA induction serves as an alternative therapeutic strategy for the treatment of PDA to the current one, i.e., inhibition of PGE signaling by cyclooxygenase inhibitors, which might delay PGE-mediated ICF in immature infants.

Authors

Utako Yokoyama, Susumu Minamisawa, Hong Quan, Shibnath Ghatak, Toru Akaike, Eri Segi-Nishida, Shiho Iwasaki, Mari Iwamoto, Suniti Misra, Kouichi Tamura, Hideaki Hori, Shumpei Yokota, Bryan P. Toole, Yukihiko Sugimoto, Yoshihiro Ishikawa

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Figure 2

Effects of chronic EP4 stimulation on DA SMC migration.

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Effects of chronic EP4 stimulation on DA SMC migration. (A) Cell migrati...
(A) Cell migration and HA production in response to long exposures (>24 hours) to ONO-AE1-329 (10–6 M). SMC migration (bar graph) and HA secretion into the media (line graph) are shown. An increase in HA production in culture media was accompanied by the time-dependent increase in SMC migration. n = 4–8; **P < 0.01, #P < 0.001 compared with control. †P < 0.05, ΧP < 0.001 compared with HA production at 24 hours. (B) ONO-AE1-329–induced HA production is responsible for increased migration. The ONO-AE1-329–induced SMC migration was significantly attenuated by daily exchange of culture media (EXC); addition of hyaluronidase (HAD) (0.02 mg/ml: HAD 0.02; 0.05 mg/ml: HAD 0.05) to culture media; or transfection with rat HAS2 siRNA (100 pmol). HA (50 ng/ml: HA 50; 200 ng/ml: HA 200) alone was sufficient to stimulate DA SMC migration to the same or a higher level as was ONO-AE1-329 (10–6 M). n = 4; **P < 0.01, #P < 0.001 compared with control (10–6 M ONO-AE1-329).