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NF-κB is involved in the LPS-mediated proliferation and apoptosis of MAC-T epithelial cells as part of the subacute ruminal acidosis response in cows

Fan, Wen-Jie, Li, He-Ping, Zhu, He-Shui, Sui, Shi-Ping, Chen, Pei-Ge, Deng, Yue, Sui, Tong-Ming, Wang, Yue-Ying
Biotechnology letters 2016 v.38 no.11 pp. 1839-1849
Western blotting, apoptosis, cell proliferation, cows, cultured cells, cytotoxicity, epithelial cells, in vitro culture, inflammation, lipopolysaccharides, mammary glands, reverse transcriptase polymerase chain reaction, ruminal acidosis, signal transduction, transcription factor NF-kappa B
OBJECTIVES: To determine the effect of NF-κB on cell proliferation and apoptosis, we investigate the expression of inflammation and apoptosis-related factors in the bovine mammary epithelial cell line, MAC-T. RESULTS: MAC-T cells were cultured in vitro and MTT and LDH assays used to determine the effects of lipopolysaccharide (LPS) on proliferation and cytotoxicity respectively. RT-PCR and western blotting were used to evaluate the effect of LPS and NF-κB inhibition [pyrrolidine dithiocarbamate (PDTC) treatment] on the expression of inflammation and apoptosis-related factors. LPS significantly inhibited MAC-T cell proliferation in a dose- and time-dependent manner. Furthermore, LPS promoted apoptosis while the NF-кB inhibitor PDTC attenuated this effect. After LPS treatment, the NF-кB signaling pathway was activated, and the expression of inflammation and apoptosis-related factors increased. When PDTC blocked NF-кB signaling, the expression of inflammation and apoptosis-related factors were decreased in MAC-T cells. CONCLUSIONS: LPS activates the TLR4/NF-κB signaling pathway, inhibits proliferation and promotes apoptosis in MAC-T cells. NF-кB inhibition attenuates MAC-T cell apoptosis and TLR4/NF-κB signaling pathway. NF-кB inhibitor alleviating MAC-T cell apoptosis is presumably modulated by NF-кB.