Dissertation > Excellent graduate degree dissertation topics show

Research on NF-κB Pathway Negative Regulation Keap1-Nrf2 Pathway and Its Molecular Mechanism

Author: LiHui
Tutor: YangXiaoMing
School: Tianjin University
Course: Pharmaceutical Engineering
Keywords: NF-κB pathway Nrf2 pathway p65 protein Keap1 protein Protein-protein interaction
CLC: Q257
Type: Master's thesis
Year: 2009
Downloads: 294
Quote: 0
Read: Download Dissertation

Abstract

NF-κB and Nrf2 are the major transcription factors that are involved in regulating proinflammatory and antioxidant genes, respectively. A variety of anti-inflammatory or anti-carcinogenetic phytochemicals surppress NF-κB signaling and activites Nrf2 as well. In consideration of close association between anti-inflammatory and antioxitant properties mediated by the same stimulus, it is worthwhile determining the cross-talk between NF-κB and Nrf2 signaling. Considering that, our research focuses on the crosstalk between NF-κB and Nrf2 signaling.First of all, we have established the luciferase reporter gene system for testing the two transcription factor activity and verified its effectiveness. Then we study the effct of TNF-α, IL-1βand PMA on the NF-κB and Nrf2 pathway, and found that the three stimulus have slight negative regulation of the Nrf2 pathway while activiting the NF-κB pathway. Furthermore, on the one hand, the distinct levels of NF-κB pathway proteins, which can activate NF-κB, have negative regulation of Nrf2 pathway at the same time, on the other hand, IκBα, the negative regulator of NF-κB, can activate Nrf2 pathway. In preliminary studies in our laboratory, we found that whether activation or inhibition of Keap1-Nrf2 pathway has no effect on the NF-κB pathway. And the results above suggest that the activation of NF-κB pathway may negative regulate of Nrf2 pathway. The inhibition of Nrf2 by the TNF-α, IL-1βand PMA is significantly slight than the activation molecules of NF-κB .This may because that TNF-α, IL-1βand PMA can activate other pathways outside the NF-κB signaling pathway and there are complexity of interactions between these pathways.p65 is the downstream protein of NF-κB pathway. We have found that p65 is the most significant negative regulator of Nrf2 in the NF-κB pathway. And it also can reduce the DNA binding activity of Nrf2. According to that, we conclude that p65 is the direct functional protein in the negative regulation of NF-κB on the Nrf2 pathway. The experiments show that p65 mutant loss of transcriptional activity still has the negative regulation ability of Nrf2, which means such negative regulation is independent on p65 transcriptional activity. In preliminary studies in our laboratory, through yeast two-hybrid screening, we found that p65 interact with Keap1, the negative regulation protein of Nrf2. Based on these conclusions, we infer that p65 negative regulate Nrf2 by interacing with Keap1. According to the co-IP and the Pull Down experiments, we have confirmed the interaction between p65 and Keap1.In this investigation, we revealed that the NF-κB-p65 antagoniaed the Nrf2 pathway by direct interacting with Keap1. This conclution provides new clues of the cross-talk between the two pathways and the molecular mechanisms of signaling passway regulation. At the same time, it also deepened our recognization of the biologic functions of this two passways in the proinflammatory and antioxidant.

Related Dissertations

CLC: > Biological Sciences > Cell Biology > Cell physiology > Information transfer in cells
© 2012 www.DissertationTopic.Net Mobile