title: Lipopolysaccharide (LPS) regulates TLR4 signal transduction in nasopharynx epithelial cell line 5-8F via NFkappaB and MAPKs signaling pathways.
abstract: The lipopolysaccharide (LPS) of Gram-negative bacteria induces the expression of cytokines and proinflammatory genes via the TLR4 signaling pathway in diverse cell types. The purpose of the present study was to test the hypothesis that the nasopharynx epithelial cells (NECs) could recognize and respond to LPS. The underlying molecular mechanisms were further elucidated in the NEC line 5-8F for its ability to activate the NFkappaB and TNF-alpha reporter genes, in response to LPS. After LPS stimulation, the TNF-alpha promoter activity and the relevant production of TNF-alpha were significantly increased in 5-8F cells. Moreover, LPS activated NFkappaB p65, ERK1/2 and JNK1/2 and induced their translocation to the nucleus. Western blot analysis showed that the expression of NFkappaB p65, MEK1, ERK1/2, JNK1/2, phospho-ERK1/2 and phospho-JNK1/2 proteins also was increased in NEC 5-8F cells, following the LPS stimulation. Additionally, the expression of TLR1-6, MD2 and CD14 was examined by RT-PCR, and the CD14 expression was determined by flow cytometry analysis. We demonstrated that the expression of CD14, TLR4 and MD2 was crucial for the NEC responses to LPS. In conclusion, our results provide novel mechanisms for the response of nasopharnyx epithelial cells to LPS stimulation, through NFkappaB and MAPKs signaling pathways.
authors: Cancer Research Institute, Central South University, 110 Xiangya Road, Changsha, 410078 Hunan, PR China.
authors: Yixin
authors: Y
authors: Yang
authors: Houde
authors: H
authors: Zhou
authors: Yunbo
authors: Y
authors: Yang
authors: Weisong
authors: W
authors: Li
authors: Ming
authors: M
authors: Zhou
authors: Zhaoyang
authors: Z
authors: Zeng
authors: Wei
authors: W
authors: Xiong
authors: Minghua
authors: M
authors: Wu
authors: He
authors: H
authors: Huang
authors: Yanghong
authors: Y
authors: Zhou
authors: Cong
authors: C
authors: Peng
authors: Chen
authors: C
authors: Huang
authors: Xiaolin
authors: X
authors: Li
authors: Guiyuan
authors: G
authors: Li