Tryptase activates PKB in inflammatory reaction in ECV304 cells
Yongjie Ma1, Bin Zhang, Ruizhe Qian
1Department of Physiology, Shanghai Medical College, Fudan University, 138# Yixueyuan Road, Shanghai 200032, PR China.
Biochimica Et Biophysica Acta
|March 28, 2006
Summary
Tryptase enhances interleukin-8 (IL-8) expression by activating the phosphoinositol-3-kinase-protein kinase B (PI3K-PKB) pathway. This activation leads to increased NF-kappaB expression, a key factor in inflammatory responses.
Area of Science:
- Immunology
- Molecular Biology
- Cell Signaling
Background:
- Tryptase, an enzyme released by mast cells, is implicated in inflammatory processes.
- Proteinase-activated receptor-2 (PAR-2) signaling is known to influence cytokine expression.
- Interleukin-8 (IL-8) is a critical chemokine in inflammatory and immune responses.
Purpose of the Study:
- To investigate the effects of tryptase on gene expression and cellular activation.
- To elucidate the signaling pathways involved in tryptase-mediated IL-8 up-regulation.
- To determine the role of the PI3K-PKB pathway in tryptase-induced inflammatory gene expression.
Main Methods:
- Quantitative analysis of mRNA expression for NF-kappaB, AP-1, PKB, JNK, and p38 MAPK following tryptase treatment.
- Assessment of protein phosphorylation for p38 MAPK and PKB.
- Inhibition studies using a PI3K inhibitor (LY294002) and antisense PKB cDNA to block signaling pathways.
Main Results:
- Tryptase significantly increased mRNA expression of NF-kappaB, AP-1, and PKB, but not JNK or p38 MAPK.
- Tryptase induced phosphorylation of PKB and p38 MAPK.
- Inhibition of PI3K or PKB abolished tryptase-induced NF-kappaB up-regulation and PKB phosphorylation.
Conclusions:
- Tryptase activates the PI3K-PKB signaling pathway.
- This activation leads to enhanced expression of NF-kappaB and subsequently IL-8.
- The PI3K-PKB pathway is a key mediator of tryptase-induced inflammatory responses.
