Chronic activation of the prostaglandin receptor EP4 promotes hyaluronan-mediated neointimal formation in the ductus arteriosus
J. Clin. Invest. Utako Yokoyama, et al. 116:3026 doi:10.1172/JCI28639 [Go to this article.]

Figure 6
Has2 gene transfer promotes ICF in the DA. (A) Immature rat DA overexpressing GFP or Has2. Indomethacin (10^–5 M) was administered 72 hours after Has infection (+Ind). Scale bars: 100 μm. (B) Intimal cushion thickening was expressed as the percent of whole smooth muscle layer. (C) The size of the vascular lumen was compared in the same experiments. The neointimal cushion became thicker and the size of vascular lumen was smaller in Has2-overexpressing DA. When indomethacin (10^–5 M), a COX inhibitor, was administered 72 hours after Has2 or GFP gene transfer, the size of the vascular lumen was further decreased, whereas the thickness of intimal cushion remained unchanged. n = 5–10; **P < 0.01, ^#P < 0.001 compared with GFP. ^†P < 0.05 with indomethacin versus without indomethacin. (D) Similar images of immature rat DA explants at E19 that were incubated with ONO-AE1-329 (10^–6 M) in the absence (left) or presence (right) of hyaluronidase (0.05 mg/ml). Scale bars: 100 μm. (E) Changes in intimal cushion thickening expressed as percent of whole smooth muscle layer in ONO-AE1-329–stimulated DA in the absence or presence of HAD. EP4-mediated ICF was significantly attenuated in DA explants in the presence of HAD. n = 3; *P = 0.041. (F) Similar images of EP4-KO DA explants overexpressing GFP or Has2 at E18.5. Scale bars: 100 μm. (G) Changes in intimal cushion thickening in Has2-overexpressing EP4-KO DA. ICF was significantly increased in DA explants by HAS2 gene transfer. n = 3; ^ζP = 0.035. SM, smooth muscle.