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Pro-inflammatory cytokines reduce human TAFI expression via tristetraprolin-mediated mRNA destabilisation and decreased binding of HuR.
Komnenov, D; Scipione, C A; Bazzi, Z A; Garabon, J J W; Koschinsky, M L; Boffa, M B.
Afiliação
  • Boffa MB; Michael B. Boffa, PhD, Department of Chemistry & Biochemistry, University of Windsor, Windsor, Ontario, Canada, Tel.: +1 519 253 3000 ext 3537, Fax: +1 519 973 7098, E-mail: mboffa@uwindsor.ca.
Thromb Haemost ; 114(2): 337-49, 2015 Aug.
Article em En | MEDLINE | ID: mdl-26062599
ABSTRACT
Thrombin activatable fibrinolysis inhibitor (TAFI) is the zymogen form of a basic carboxypeptidase (TAFIa) with both anti-fibrinolytic and anti-inflammatory properties. The role of TAFI in inflammatory disease is multifaceted and involves modulation both of specific inflammatory mediators as well as of the behaviour of inflammatory cells. Moreover, as suggested by in vitro studies, inflammatory mediators are capable of regulating the expression of CPB2, the gene encoding TAFI. In this study we addressed the hypothesis that decreased TAFI levels observed in inflammation are due to post-transcriptional mechanisms. Treatment of human HepG2 cells with pro-inflammatory cytokines TNFα, IL-6 in combination with IL-1ß, or with bacterial lipopolysaccharide (LPS) decreased TAFI protein levels by approximately two-fold over 24 to 48 hours of treatment. Conversely, treatment of HepG2 cells with the anti-inflammatory cytokine IL-10 increased TAFI protein levels by two-fold at both time points. We found that the mechanistic basis for this modulation of TAFI levels involves binding of tristetraprolin (TTP) to the CPB2 3'-UTR, which mediates CPB2 mRNA destabilisation. In this report we also identified that HuR, another ARE-binding protein but one that stabilises transcripts, is capable of binding the CBP2 3'UTR. We found that pro-inflammatory mediators reduce the occupancy of HuR on the CPB2 3'-UTR and that the mutation of the TTP binding site in this context abolishes this effect, although TTP and HuR appear to contact discrete binding sites. Interestingly, all of the mediators tested appear to increase TAFI protein expression in THP-1 macrophages, likewise through effects on CPB2 mRNA stability.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: RNA Mensageiro / Regulação Neoplásica da Expressão Gênica / Lipopolissacarídeos / Mediadores da Inflamação / Regiões 3' não Traduzidas / Estabilidade de RNA / Hepatócitos / Carboxipeptidase B2 / Tristetraprolina / Proteína Semelhante a ELAV 1 Tipo de estudo: Prognostic_studies Limite: Humans Idioma: En Ano de publicação: 2015 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: RNA Mensageiro / Regulação Neoplásica da Expressão Gênica / Lipopolissacarídeos / Mediadores da Inflamação / Regiões 3' não Traduzidas / Estabilidade de RNA / Hepatócitos / Carboxipeptidase B2 / Tristetraprolina / Proteína Semelhante a ELAV 1 Tipo de estudo: Prognostic_studies Limite: Humans Idioma: En Ano de publicação: 2015 Tipo de documento: Article