Caffeic Acid Prevented LPS-Induced Injury of Primary Bovine Mammary Epithelial Cells through Inhibiting NF-κB and MAPK Activation

• Published in: Mediators of inflammation Vol. 2019; no. 2019; pp. 1 - 12
• Main Authors: Zongping, Liu, Zhang, Chi, Zhao, Xin, Yin, Shaojie, Fang, Guoqing, Liu, Mingjiang, Li, Jingui
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 2019; Hindawi; Hindawi Limited
• Subjects: Acids; Animals; Antibiotics; Apoptosis; Apoptosis - drug effects; Bax protein; Bcl-2 protein; Biology; Blotting, Western; c-Jun protein; Caffeic acid; Caffeic Acids - pharmacology; Cattle; Cell injury; Cell viability; Cytology; DNA, Complementary - metabolism; Drug resistance; E coli; Endoplasmic reticulum; Epithelial cells; Epithelial Cells - metabolism; Genomes; Genomics; Homeostasis; Inflammation; Inflammatory bowel disease; Interleukin 6; Interleukin 8; Interleukin-1beta - metabolism; Interleukin-6 - metabolism; Interleukin-8 - metabolism; Lipopolysaccharides; Lipopolysaccharides - pharmacology; Mammary gland; Mammary Glands, Animal - cytology; Mammary Glands, Animal - metabolism; MAP kinase; Membrane potential; Membrane Potential, Mitochondrial - drug effects; Membrane Potential, Mitochondrial - physiology; Milk; Mitochondria; NF-kappa B - metabolism; NF-κB protein; Pathogenesis; Ribonucleic acid; RNA; Scanning electron microscopy; Signal transduction; Signal Transduction - physiology; Structure-function relationships; Transcription factors; Tumor Necrosis Factor-alpha - metabolism; Tumor necrosis factor-TNF; Tumor necrosis factor-α; Watson, C J; United States > US; Japan; Grand Island New York
• ISSN: 0962-9351; 1466-1861
• DOI: 10.1155/2019/1897820

In our previous study, lipopolysaccharide (LPS) significantly reduced the cell viability of primary bovine mammary epithelial cells (bMEC) leading to cell apoptosis, which were prevented by caffeic acid (CA) through inhibiting NF-κB activation and reducing proinflammatory cytokine expression. While the underlying mechanism remains unclear, here, we determined that LPS induced the extensive microstructural damage of bMEC, especially the mitochondria and endoplasmic reticulum. Then, the obvious reduction of mitochondrial membrane potential and expression changes of apoptosis-associated proteins (Bcl-2, Bax, and casepase-3) indicated that apoptosis signaling through the mitochondria should be responsible for the cell viability decrease. Next, the high-throughput cDNA sequencing (RNA-Seq) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were employed to verify that the MAPK and JAK-STAT signaling pathways also were the principal targets of LPS. Following, the critical proteins (ERK, JNK, p38, and c-jun) of the MAPK signaling pathways were activated, and the release of proinflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-8) regulated by NF-κB and MAPKs was significantly increased, which can promote a cascade of inflammation that induces cell injury and apoptosis. Meanwhile, CA significantly inhibited the activation of MAPKs and the release of proinflammatory cytokines in a dose-dependent manner, which were similar to its effects on the NF-κB activation that we previously published. So we concluded that CA regulates the proteins located in the upstream of multiple cell signal pathways which can reduce the LPS-induced activation of NF-κB and MAPKs, thus weakening the inflammatory response and maintaining cell structure and function, which accordingly inhibit apoptosis.