Forsythoside A regulates autophagy and apoptosis through the AMPK/mTOR/ULK1 pathway and alleviates inflammatory damage in MAC-T cells

• Published in: International immunopharmacology 2023-05, Vol.118, p.110053-110053, Article 110053
• Main Authors: Zhang, Xing, Zhang, HuaQiang, Gao, YingKui, Hao, ZhongHua, Liu, JingJing, Zhou, GuangWei, Liu, Fang, Li, Xiao, Tong, Chao, Wang, XueBing
• Format: Article
• Language: English
• Subjects: AMP-Activated Protein Kinases - metabolism; AMPK/mTOR/ULK1; Animals; Apoptosis; Autophagy; Cattle; Female; FTA; Inflammation - drug therapy; Lipopolysaccharides - pharmacology; LPS; MAC-T; Signal Transduction; TOR Serine-Threonine Kinases - metabolism
• ISSN: 1567-5769; 1878-1705
• DOI: 10.1016/j.intimp.2023.110053

•FTA activated autophagy, attenuated inhibition of autophagy flow, and inhibited apoptosis.•Autophagy and apoptosis were mainly regulated through the AMPK/mTOR/ULK1 pathway.•FTA-mediated regulation of autophagy, apoptosis, and inflammation in MAC-T cells is dependent on AMPK activation.•Our findings may aid in the development of novel intervention strategies and drugs for bovine mastitis. Dairy cow mastitis is the most common disease encountered in dairy farming. Lipopolysaccharides (LPS), among the major virulence-related factors produced by Escherichia coli, stimulate mammary gland inflammation and cause its damage, thereby affecting milk yield and quality. Forsythoside A (FTA) is among the main active components of forsythia. Recent pharmacological studies have demonstrated that FTA possesses anti-inflammatory, antiviral, antioxidant, and other biological activities. This study investigated the effects of the FTA-activated AMP-activated protein kinase (AMPK) signaling pathway on LPS-induced autophagy, apoptosis, and inflammatory damage in bovine mammary epithelial (MAC-T) cells. Cell activity was measured using the Cell Counting Kit 8. Moreover, real-time quantitative polymerase chain reaction and western blot analyses were used to detect expression levels of autophagic, apoptotic, and inflammatory factors, as well as those of oxidative stress-related genes and proteins. The annexin-FITC/PI assay and immunofluorescence assay were used to detect the apoptosis rate and LC3B expression, respectively. We found that FTA attenuated LPS-induced inhibition of MAC-T cell proliferation, reduced mRNA expression of related inflammatory factors, relieved oxidative stress, and exerted protective effects on MAC-T cells. Additionally, FTA activated autophagy, attenuated inhibition of autophagy flow, and inhibited apoptosis. Autophagy and apoptosis were mainly regulated through the AMPK/mTOR/ULK1 pathway. The aforementioned FTA-induced effects were inhibited by the administration of Compound C (CC; an AMPK inhibitor). Taken together, these results indicate that FTA can alleviate LPS-induced inflammation and oxidative stress in MAC-T cells, attenuate impairments in autophagy, and inhibit apoptosis. However, these effects were blocked by CC, which suggests that FTA inhibits LPS-induced autophagy, apoptosis, and inflammatory damage in MAC-T cells by activating the AMPK pathway.