Factor VIIa and thrombin induce the expression of Cyr61 and connective tissue growth factor, extracellular matrix signaling proteins that could act as possible downstream mediators in factor VIIa x tissue factor-induced signal transduction.
Extracellular interactions of plasma clotting factor VIIa (FVIIa) with tissue factor (TF) on cell surfaces trigger the intracellular signaling events. At present, it is unclear how these signals influence phenotype. To elucidate this, we have used cDNA microarray technology to examine changes in transcriptional program in human fibroblasts in response to exposure to FVIIa. cDNA microarrays revealed that FVIIa binding to TF up-regulated the expression of Cyr61 and CTGF (connective tissue growth factor), the genes that encode extracellular matrix signaling proteins Cyr61 and CTGF, respectively. Northern blot analysis confirmed that FVIIa binding to TF markedly increased the expression of Cyr61 and CTGF in a time- and dose-dependent manner. FVIIa catalytic activity is required for the gene induction. In addition to FVIIa, thrombin also induced the expression of Cyr61 and CTGF. Hirudin abolished the thrombin-induced expression of these mRNAs but not the FVIIa-induced expression. FVIIa-induced expression of Cyr61 appears not to involve the currently known protease-activated receptors (PARs), whereas thrombin-induced expression involves the activation of PAR1 and possibly an additional PAR. Various intracellular signaling pathway inhibitors exhibited different inhibitory pattern on FVIIa and thrombin-induced up-regulation of Cyr61. Cyr61 and CTGF could act as downstream mediators of FVIIa x TF in affecting various biological processes.
Pendurthi
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Department of Molecular Biology, The University of Texas Health Center at Tyler, Texas 75708, USA. usha@uthct.edu
Allen
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Ezban
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Rao
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D002460:Cell Line; D055513:Connective Tissue Growth Factor; D055515:Cysteine-Rich Protein 61; D018076:DNA, Complementary; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000502:physiology*; D015942:Factor VIIa / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology*; D006133:Growth Substances / Q000235:genetics / Q000502:physiology*; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics / Q000502:physiology*; D036341:Intercellular Signaling Peptides and Proteins; D007700:Kinetics; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction; D013917:Thrombin / Q000502:physiology*; D014158:Transcription, Genetic; D015533:Transcriptional Activation
C501848:CCN1 protein, human; C526317:CCN2 protein, human; D055515:Cysteine-Rich Protein 61; D018076:DNA, Complementary; D016326:Extracellular Matrix Proteins; D006133:Growth Substances; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D055513:Connective Tissue Growth Factor; D015942:Factor VIIa; D013917:Thrombin