IKKε knockout alleviates angiotensin II-induced apoptosis and excessive autophagy in vascular smooth muscle cells by regulating the ERK1/2 pathway

Inhibitor of nuclear factor-κB kinase subunit ε (IKKε) is an important signal regulator in the formation of abdominal aortic aneurysm (AAA). However, the underlying mechanism remains to be elucidated. Therefore, the present study aimed to investigate the mechanism underlying IKKε function in AAA formation by studying apoptosis and autophagy in angiotensin II (Ang II)-induced vascular smooth muscle cells (VSMCs). AngII was used to stimulate VSMCs for 24 h to simulate the process of AAA formation. VSMCs were transfected with IKKε small interfering RNA to investigate the effect of IKKε on AAA formation, cell apoptosis and autophagy. IKKε deficiency led to reduced mitochondrial damage and apoptosis in VSMCs in the early stage of apoptosis in vitro, as demonstrated using a JC-1 probe. IKKε deficiency also reduced autophagy and decreased the formation of autophagic vacuoles in VSMCs, demonstrated using transmission electron microscopy. The decrease in apoptosis caused by IKKε knockdown was reversed when the autophagic flow was blocked using bafilomycin A1. Western blot analysis further revealed that IKKε deficiency negatively regulated the ERK1/2 signaling pathway to reduce autophagy. Collectively, the results of the present study revealed that IKKε played a key role in apoptosis by inducing excessive autophagy, thereby potentially contributing to AAA formation. These findings further revealed the mechanism underlying IKKε function in the formation of AAA.