Yingqian Han

Effective intervention on oxidative damage of bovine mammary epithelial cells (bMECs) is particularly important for reducing the incidence rate of mastitis. As a natural antioxidant, resveratrol (RES) can scavenge ROS, protecting cells from oxidative damage. However, the role of RES in bMECs and its potential protective mechanism have not been fully elucidated. Our results indicated that RES alleviated oxidative damage and enhanced antioxidant capacity in bMECs. Furthermore, RES increased SIRT5 expression and interacted with SIRT5, which attenuated cellular oxidative stress, inflammatory response and autophagy activity. Interestingly, SIRT5 and RES further improved mitochondrial dysfunction by increasing intracellular NADPH and GSH levels. Meanwhile, RES activated SIRT5 to regulate enzymatic activity of SDH and IDH2, which were important enzymes for producing intracellular ATP and antioxidants. RES specifically activated SIRT5 to attenuate the succinylation levels of intracellular IDH2 associated with interacting with SIRT5. Collectively, these outcomes revealed that RES might function as an activator of SIRT5 to attenuate oxidative damage of bMECs via activating SIRT5-IDH2 axis, resulting in increased GSH and NADPH production. Therefore, RES may be useful to prevent and control bovine mastitis by relieving oxidative damage.

Objective This study investigates the role of the aryl hydrocarbon receptor (AhR) in lipopolysaccharide (LPS)-induced inflammatory responses in IPEC-J2 cells. Methods Inflammatory responses were triggered in IPEC-J2 cells using 5 μg/ml LPS. AhR was activated with tryptophan or FICZ and knocked down via RNA interference. PINK1/Parkin-mediated mitophagy was activated using CCCP and inhibited by PINK1 knockdown. Inflammatory mediators and pathway proteins were analyzed through ELISA, RT-qPCR, western blot, and immunofluorescence. Mitochondrial function was assessed by measuring ROS, ATP, and mitochondrial membrane potential. The interaction between AhR and PINK1 was examined using dual-luciferase reporter assays. Results The IDO1/AhR signaling axis was activated in LPS-stimulated IPEC-J2 cells. AhR activation was found to attenuate LPS-induced inflammatory responses, whereas AhR knockdown exacerbated these responses. Mechanistic investigations demonstrated that AhR activation alleviated LPS-induced mitochondrial damage. Activating PINK1/Parkin-mediated mitophagy successfully countered the increased inflammatory response in IPEC-J2 cells after AhR knockdown. Moreover, blocking PINK1 reversed the anti-inflammatory effects of FICZ. Dual-luciferase reporter assays revealed that AhR acts as a crucial transcription factor by directly binding to the promoter region, thereby initiating PINK1 transcription. Conclusions AhR reduces LPS-induced inflammatory response in IPEC-J2 cells by activating PINK1/Parkin-mediated mitophagy, with AhR directly engaging the PINK1 promoter to enhance its transcription. Targeting AhR may present a novel strategy for the prevention and management of Escherichia coli-induced diarrhea in piglets.