Daxx ameliorates abdominal aortic aneurysm through inhibiting the TGF-β1-mediated PI3K/AKT/ID2 signaling pathway

Abstract

Background Abdominal aortic aneurysm (AAA) is a potentially life-threatening vascular abnormality, that, if ruptured, is almost universally fatal without repair, and is associated with up to 50% mortality even if repaired in hospital. To date, there is no drug therapy that has clinically proven benefit to reduce or prevent expansion of AAA. The aim of this study was to investigate whether Daxx could affect AAA through inhibiting the PI3K/AKT/ID2 signaling pathway mediated by transforming growth factor β-1 (TGFβ1). Methods The AAA model was constructed by injecting angiotensin Ⅱ (Ang-Ⅱ) into rats, and the Daxx lentivirus vector was constructed. Hematoxylin and eosin (HE) staining was used to detect the wall thickness of the abdominal aorta in rats. The gene and protein expressions in abdominal aortic tissues were detected utilizing western blot, immunohistochemistry (IHC) and fluorescence quantitative real-time polymerase chain reaction (qRT-PCR). Finally, the concentration of TGF-β1 in abdominal aortic tissue was determined by ELISA. Results The abdominal aortic wall thickness was decreased in the Daxx expression group (by HE staining), and Daxx overexpression markedly reduced the protein expression levels of MMP2 and MMP9. Proteins related to the PI3K/AKT/ID2 signaling pathway were highly enhanced in the aneurysm wall of rats, but were reduced following Daxx addition. Moreover, Daxx reduced the damage to elastin (by IHC), and the expression levels of α-SMA and SM22α were up-regulated by Daxx (by qRT-PCR). The concentration of TGF-β1 was correlated with the activation of the PI3K/AKT/ID2 signaling pathway (by ELISA), whereas AKT overexpression weakened the inhibitory effect of Daxx. Conclusion Daxx ameliorated several mechanisms that contributed to expansion of AAA suppressing the tissue concentration of TGF-β1, thereby inhibiting the activation of the PI3K/AKT/ID2 signaling pathway. This evidence might form the basis to develop a therapeutic target for AAA.