14-3-3? Regulates Lipopolysaccharide-Induced Inflammatory Responses and Lactation in Dairy Cow Mammary Epithelial Cells by Inhibiting NF-?B and MAPKs and Up-Regulating mTOR Signaling.

ABSTRACT: As a protective factor for lipopolysaccharide (LPS)-induced injury, 14-3-3? has been the subject of recent research. Nevertheless, whether 14-3-3? can regulate lactation in dairy cow mammary epithelial cells (DCMECs) induced by LPS remains unknown. Here, the anti-inflammatory effect and lactation regulating ability of 14-3-3? in LPS-induced DCMECs are investigated for the first time, and the molecular mechanisms responsible for their effects are explored. The results of qRT-PCR showed that 14-3-3? overexpression significantly inhibited the mRNA expression of tumor necrosis factor-? (TNF-?), interleukin-6 (IL-6), interleukin-1? (IL-1?) and inducible nitric oxide synthase (iNOS). Enzyme-linked immunosorbent assay (ELISA) analysis revealed that 14-3-3? overexpression also suppressed the production of TNF-? and IL-6 in cell culture supernatants. Meanwhile, CASY-TT Analyser System showed that 14-3-3? overexpression clearly increased the viability and proliferation of cells. The results of kit methods and western blot analysis showed that 14-3-3? overexpression promoted the secretion of triglycerides and lactose and the synthesis of ?-casein. Furthermore, the expression of genes relevant to nuclear factor-?B (NF-?B) and mitogen-activated protein kinase (MAPKs) and lactation-associated proteins were assessed by western blot, and the results suggested that 14-3-3? overexpression inactivated the NF-?B and MAPK signaling pathways by down-regulating extracellular signal regulated protein kinase (ERK), p38 mitogen-activated protein kinase (p38MAPK) and inhibitor of NF-?B (I?B) phosphorylation levels, as well as by inhibiting NF-?B translocation. Meanwhile, 14-3-3? overexpression enhanced the expression levels of ?-casein, mammalian target of rapamycin (mTOR), ribosomal protein S6 kinase 1 (S6K1), serine/threonine protein kinase Akt 1 (AKT1), sterol regulatory element binding protein 1 (SREBP1) and peroxisome proliferator-activated receptor gamma (PPAR?). These results suggest that 14-3-3? was able to attenuate the LPS-induced inflammatory responses and promote proliferation and lactation in LPS-induced DCMECs by inhibiting the activation of the NF-?B and MAPK signaling pathways and up-regulating mTOR signaling pathways to protect against LPS-induced injury.

SUBMITTER: Liu L 

PROVIDER: S-EPMC4519969 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature