Inhibitors of mPges-1 are in the early phase of clinical development. Deletion of mPges-1 in mice confers analgesia, restrains atherogenesis and fails to accelerate thrombogenesis, while suppressing PGE2, but increasing biosynthesis of PGI2. In Ldlr-/- mice, this last effect represents the dominant mechanism by which mPges-1 deletion restrains thrombogenesis, while suppression of PGE2 accounts for its anti-atherogenic effect. However, the impact of mPges-1 depletion on BP in this setting remains unknown. Here, mPges-1 depletion significantly increased the BP response to salt loading in male Ldlr-/- mice, whereas, despite the direct vasodilator properties of PGI2, Ipr deletion suppressed it. Furthermore, combined deletion of the Ipr abrogated the exaggerated BP response in male mPges-1-/- mice. Interestingly, these unexpected BP phenotypes were not observed in female mice fed a high salt diet. This is attributable to the protective effect of estrogen in Ldlr-/- mice and in Ipr-/- /Ldlr-/- mice. Thus, estrogen compensates for a deficiency in PGI2 to maintain BP homeostasis in response to high salt in hyperlipidemic female mice. In males, by contrast, augmented formation of ANP plays a similar compensatory role, restraining hypertension and oxidant stress in the setting of Ipr depletion. Hyperlipidemic males on a high salt diet might be at risk of a hypertensive response to mPGES-1 inhibitors.
Soon Y. Tang, Hu Meng, Seán T. Anderson, Dimitra Sarantopoulou, Soumita Ghosh, Nicholas F. Lahens, Katherine N. Theken, Emanuela Ricciotti, Elizabeth J. Hennessy, Vincent Tu, Kyle Bittinger, Aalim M. Weljie, Gregory R. Grant, Garret A. FitzGerald