Paricalcitol Pretreatment Attenuates Renal Ischemia-Reperfusion Injury via Prostaglandin E₂ Receptor EP4 Pathway

Figure 4

Paricalcitol induced EP4-mediated phosphorylation of Akt and CREB in HK-2 cells with ischemia exposure. (a) Semiquantitative immunoblot analysis showed that in vitro ischemia induced Akt phosphorylation and that it was further enhanced after paricalcitol. The upregulated Akt phosphorylation in paricalcitol-treated cells was attenuated by AH-23848 cotreatment. (b) EP4-specific siRNA significantly inhibited the phosphorylation of Akt in IR-exposed cells treated with paricalcitol. (c) CREB phosphorylation was significantly increased in IR-exposed cells, and paricalcitol pretreatment further increased CREB phosphorylation. AH-23848 cotreatment decreased the phosphorylation of CREB. (d) EP4 siRNA significantly inhibited phosphorylation of CREB in IR-exposed cells treated with paricalcitol. Each column represents the mean ± SEM of three independent experiments. .

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