Congress of the International Society on Thrombosis and Haemostasis

Regulation of mouse thrombin-activable fibrinolysis inhibitor gene expression by inflammatory cytokines

Abstract number: OC-WE-109

Garand¹ M., Jiang¹ N., Hill² C.E., Koschinsky³ M.L., Boffa³ M.B.

¹¹Biochemistry ²²Biology, Queen's University, Kingston ³³Chemistry and Biochemistry, University of Windsor, Windsor, Canada

How-to-cite Garand M, Jiang N, Hill CE, Koschinsky ML, Boffa MB. Regulation of mouse thrombin-activable fibrinolysis inhibitor gene expression by inflammatory cytokines. Journal of Thrombosis and Haemostasis 2009; Volume 7, Supplement 2: Abstract OC-WE-109

Thrombin-activable fibrinolysis inhibitor (TAFI) is a plasma pro-carboxypeptidase that, once converted to its active form (TAFIa), down-regulates fibrinolysis. In addition, anaphylatoxins and bradykinin have been shown to be substrates for TAFIa, suggesting that TAFIa may also fulfill anti-inflammatory functions. We have shown that TAFI mRNA abundance in human hepatoma (HepG2) was decreased by ∼60% following 24 h of combined IL-1beta and IL-6 (IL-1beta/IL-6) treatment. On the other hand, mouse TAFI mRNA expression and TAFIa activity were found to increase within 24 h after intra-peritoneal lipopolysaccharide injection. To better understand the mechanisms by which TAFI is regulated in mice, we have evaluated the regulation of the mouse TAFI gene expression by inflammatory mediators. Our results showed that treatment of primary mouse hepatocytes with the inflammatory cytokines IL-1beta/IL-6 and TNFalpha for 24 h results in a 1.5 to 2-fold increase in TAFI mRNA abundance. After 48 h of IL-1beta, TNFalpha and IL-1beta/IL-6 treatment, we found a 2.5, 2, and 4-fold increase in TAFI mRNA abundance, respectively. Next, mouse hepatocytes (FL83B) were transfected with reporter plasmids containing the mouse TAFI 5′-flanking region. Treatment with TNFalpha for 24 and 48 h showed a ∼1.5-fold increased in mouse TAFI promoter activity. Analysis of the mouse TAFI promoter revealed the presence of a putative NFKappaB site that is not conserved between human and mouse. Mutation of the NFKappaB site ablated the modest induction of the promoter activity by TNFalpha. Using gel mobility shift assays, we found that this NFKappaB site binds NFKappaB present in nuclear extracts harvested from TNFalpha and IL-1beta-treated HepG2 cells. These findings suggest that the NFKappaB site in the mouse TAFI promoter is functional and potentially mediates the cytokine induction of the mouse TAFI gene transcription.

Disclosure of interest: none declared.

To cite this abstract use the following format:

Journal of Thrombosis and Haemostasis 2007; Volume 5, Supplement 2: abstract number

Session Details

Date:	Unpresented
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Session name:	ISTH2009
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