Increased Angiotensin II–Induced Hypertension and Inflammatory Cytokines in Mice Lacking Angiotensin-Converting Enzyme N Domain Activity

Abstract—Angiotensin-converting enzyme (ACE) is composed of the N- and C-terminal catalytic domains. To study the role of the ACE domains in the inflammatory response, N-knockout (KO) and C-KO mice, models lacking 1 of the 2 ACE domains, were analyzed during angiotensin II–induced hypertension. At 2 weeks, N-KO mice have systolic blood pressures that averaged 1734.6 mm Hg, which is more than 25 mm Hg higher than the blood pressures observed in wild-type or C-KO mice (1463.2 and 1474.2 mm Hg). After 3 weeks, blood pressure differences between N-KO, C-KO, and wild-type were even more pronounced. Macrophages from N-KO mice have increased expression of tumor necrosis factor after stimulation with either lipopolysaccharide (about 4-fold) or angiotensin II (about 2-fold), as compared with C-KO or wild-type mice. Inhibition of the enzyme prolyl oligopeptidase, responsible for the formation of acetyl-SerAspLysPro and other peptides, eliminated the blood pressure difference and the difference in tumor necrosis factor expression between angiotensin II–treated N-KO and wild-type mice. However, this appears independent of acetyl-SerAspLysPro. These data establish significant differences in the inflammatory response as a function of ACE N- or C-domain catalytic activity. They also indicate a novel role of prolyl oligopeptidase in the cytokine regulation and in the blood pressure response to experimental hypertension. (Hypertension. 2012;59:00-00.) ● Online Data Supplement Key Words: angiotensin-converting enzyme hypertension angiotensin II prolyl oligopeptidase acetyl SDK