IKK epsilon protects against starvation-induced NLRP3 inflammasome and pyroptosis in H9c2 cells by alleviating mitochondrial injury

The deprivation of myocardial nutrition causes cardiomyocyte death and disturbance of energy meta-bolism. IKKE plays an important regulatory role in many biological events such as inflammation, redox reaction, cell death, etc. However, the more in-depth mechanism by which IKKE contributes to car-diomyocytes death in nutrition deprivation remains poorly understood. IKKE expression was knocked down by siRNA in H9c2 cells, and cells were cultured under starvation conditions to simulate ischemic conditions. Starvation triggered greater NLRP3 activation, accompanied by more IL-113, IL-18 and caspase-1 release in the siIKKE H9c2 cells compared with the control H9c2 cells. Western blot and immunoflu-orescence showed that the IKKE konckdown promoted NLRP3 expressions and ROS release under star-vation conditions. Furthermore, electron micrography and JC-1 analysis revealed that IKKE konckdown resulted in aggravated mitochondrial damage and more mitochondrial ROS (mtROS) released in vitro. Notably, Western blot analysis showed that IKKE deficiency activated the TBK1 and IRF3 signaling pathways to promote pyroptosis in vitro. Collectively, our results indicate that IKKE protects against cardiomyocyte injury by reducing mitochondrial damage and NLRP3 expression following nutrition deprivation via regulation of the TBK1/IRF3 signaling pathway. This study further revealed the mecha-nism of IKKE in inflammation and myocardial nutrition deprivation. (c) 2021 Published by Elsevier Inc.