Luteolin attenuates LPS-induced damage in IPEC-J2 cells by enhancing mitophagy via AMPK signaling pathway activation

Abstract Luteolin (LUT), a flavonoid compound widely presenting in natural plants, has been extensively studied for its diverse biological properties, involving anti-inflammatory, antioxidant, anti-apoptosis and other properties. The aim of this study was to investigate the effect of LUT on lipopolysaccharide (LPS)-induced IPEC-J2 cell damage and its underlying mechanism. Results showed that LPS treatment induced injury in IPEC-J2 cells, leading to tight junction disruption, ROS accumulation, and cell apoptosis. Remarkably, LUT attenuated LPS-induced IPEC-J2 cells damage by the up-regulation of ZO-1, Occludin, and Claudin-1 protein expression levels. Besides, LUT increased the activities of CAT, and SOD and prevented LPS-induced MDA and ROS production. LUT suppressed NF-κB activation in LPS-induced IPEC-J2 cells, reducing IL-1β, IL-6 and TNF-α expression. Moreover, LUT attenuated LPS-induced apoptosis in IPEC-J2 cells by up-regulating expression of Bcl-2 and down-regulating expression of Caspase-3, Caspase-9 and Bax. Furthermore, LUT upregulated AMPK/ULK signaling pathway and Parkin/PINK1 mediated-mitophagy in dose-dependent manner. While knockdown of AMPK by short-hairpin RNA (shRNA) weakens the protect effects of LUT against LPS-induced IPEC-J2 cells damage, as evidenced by the accumulation of excessive ROS and impaired mitophagy. In summary, LUT exhibits the ability to protect against LPS-induced damage to intestinal tight junctions by enhancing mitophagy through via AMPK activation.