Abstract 13775: Increased Atherosclerosis in the Lack of IkBNS in LDL Receptor-deficient Mice is Associated With Increased Interleukin-6 Production by Macrophages
Background: IκBNS is a nuclear IκB protein which regulates nuclear factor-κB dependent interleukin (IL) -6 production. Although IL-6 is an important biomarker for cardiovascular diseases, the role of IκBNS in the development of atherosclerosis is poorly understood.
Methods and Results: Mice that lacked IκBNS (IκBNS-/-) were crossed with LDL receptor-deficient (LDLr-/-) mice and formation of atherosclerotic lesion was analyzed after 16 weeks consumption of a high-fat diet. When compared with single LDLr-/- mice (n=6), the surface atherosclerotic lesions in aortas were significantly increased in IκBNS-/-LDLr-/- mice (n=6) (22.7 ± 3.0% vs. 6.2 ± 1.4 %; p <0.001)(Figure). Immunostaining revealed significant increase in both Mac-3-positive (1.6-fold, p <0.05) and α-SMA-positive (3.6-fold, p <0.01) lesions in IκBNS-/-LDLr-/- mice compared with LDLr-/- mice. Furthermore, IL-6 expression (2.2-fold, p<0.001), and percent phospho-STAT3-positive cell (1.9-fold, p<0.05) were increased in IκBNS-/-LDLr-/- mice, indicating IκBNS deficiency promoted proliferation of both macrophage and smooth muscle cells via the IL-6-Stat3 signaling pathway. Then, we studied the function of macrophages. After LPS stimulation, the mRNA levels of both IL-6 (2.4-fold, p<0.001) and IL-18 (1.4-fold, p<0.05) were increased in the macrophages from IκBNS-/-LDLr-/- mice compared with LDLr-/- mice. Moreover, ELISA experiments revealed IκBNS-/-LDLr-/- macrophages produce much higher level of IL-6 in culture supernatants compared with LDL-/- macrophages (1.9-fold, p<0.01).
Conclusions: The present study shows that IκBNS gene deficiency in atherogenic mice led to the increase of IL-6 production and the development of atherosclerosis.
Author Disclosures: K. Akita: None. K. Isoda: None. Y. Sato-Okabayashi: None. Y. Ishii: None. K. Shimada: None. H. Daida: None.
- © 2015 by American Heart Association, Inc.