The link between cardiovascular disease (CVD) and patients with chronic inflammation is not clearly understood. We examined a knock-in mouse expressing a poly-ubiquitin-binding-defective mutant of the protein ABIN1 (ABIN1(D485N)), which develops a systemic lupus erythematosus-like autoimmune disease because of the hyperactivation of IκB kinases (IκKs) and mitogen-activated protein kinases (MAPKs). These mice were used to determine the potential role of these signaling pathways in inflammation-mediated CVD development.
Laser Doppler imaging in combination with the iontophoresis of vasoactive chemicals were used to assess endothelium-dependent vasodilatation in vivo in ABIN1 (D485N)) mutant defective (n=29) and wild-type (WT) control (n=26) mice. Measurements were made at baseline, and animals were subdivided to receive either chow or a proatherogenic diet for 4 weeks, after which, follow-up assessments were made. Paired and unpaired t tests, and ANOVA with post hoc Bonferroni correction were used for statistical significance at P<0.05.
Endothelium-dependent vasodilatation to acetylcholine was attenuated at 4 weeks in ABIN1(D485N)-chow-fed mice compared with age-matched WT-chow-fed mice (P<0.05). The magnitude of attenuation was similar to that observed in WT-cholesterol-fed animals (versus WT-chow, P<0.01). ABIN1(D485N)-cholesterol-fed mice had the poorest endothelium-dependent responses compared with other groups (P<0.001). ABIN1(D485N)-chow-fed mice had increased plasma interleukin-6 (IL-6) levels (versus WT-chow, P<0.001), and this was further elevated in ABIN1(D485N)-cholesterol-fed mice (versus ABIN1(D485N)-chow; P<0.05). IL-1α was significantly greater in all groups compared with WT-chow (P<0.01). ABIN1(D485N) mice showed significant cardiac hypertrophy (P<0.05).
The ABIN(D485N) mice display endothelial dysfunction and cardiac hypertrophy, which is possibly mediated through IL-6 and, to a lesser degree, IL-1α. These results suggest that the ABIN1-mediated hyperactivation of IKKs and MAPKs might mediate chronic inflammation and CVD development.