Involvement of plasminogen activator inhibitor-1 and its related molecules in atrial fibrosis in patients with atrial fibrillation

Atrial fibrillation is the most common form of cardiac arrhythmia. Atrial fibrosis is a significant feature of atrial fibrillation though its mechanism is not well understood. We searched the Gene Expression Omnibus database to compare mRNA expression patterns between atrial fibrillation and sinus rhythm samples; one hundred and forty eight differentially expressed genes were identified. Most of these genes were significantly enriched in the extracellular matrix organization process and collagen-activated tyrosine kinase receptor signaling pathway. To screen hub genes involved in atrial fibrosis, we constructed a protein-protein interaction network and found that three hub genes (SERPINE1/plasminogen activator inhibitor-1/PAI-1, TIMP Metallopeptidase Inhibitor 3/TIMP3 and decorin/DCN) play vital roles in atrial fibrosis, especially plasminogen activator inhibitor-1. Elevated plasminogen activator inhibitor-1 expression was positively correlated with the p53 signaling pathway. Plasminogen activator inhibitor-1 and p53 protein expression levels were verified in patients with sinus rhythm and atrial fibrillation by Western blot analysis. Compared with the sinus rhythm controls, p53 and plasminogen activator inhibitor-1 protein expressions were upregulated in the atrial tissues of patients with atrial fibrillation. p53 was also found to regulate plasminogen activator inhibitor-1 based on the results of cellular and molecular experiments. Thus, the p53/plasminogen activator inhibitor-1 signaling axis may participate in the pathophysiological processes of atrial fibrillation, and plasminogen activator inhibitor-1 may serve as a new therapeutic biomarker in atrial fibrillation.

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Characterization of Signal Transduction Pathway in Neurotropic Action of Angiotensin II in Brain Neurons

Endocrinology ◽

10.1210/endo.142.8.8348 ◽

2001 ◽

Vol 142 (8) ◽

pp. 3502-3511 ◽

Cited By ~ 9

Author(s):

Hong Yang ◽

Xiangyu Wang ◽

Mohan K. Raizada

Keyword(s):

Angiotensin Ii ◽

Plasminogen Activator ◽

Signaling Pathway ◽

Plasminogen Activator Inhibitor ◽

Neurotropic Activity ◽

Plasminogen Activator Inhibitor 1 ◽

P70s6 Kinase ◽

Activator Inhibitor ◽

Angiotensin Type

Abstract Interaction of angiotensin II with the neuronal angiotensin type 1 receptor stimulates the PI3K signaling pathway. Our objective in this study was to investigate the hypothesis that the PI3K cascade regulates the neurotropic actions of angiotensin II in rat brain neurons. We followed growth associated protein-43 expression and neurite extension as markers of neurotropic activity. Angiotensin II, through its interaction with the angiotensin type 1 receptor, increased growth associated protein-43 expression and neurite extension. These effects were abolished by pretreatment of neurons with wortmannin and rapamycin, but not by PD 98059. Antisense oligonucleotides specific for p70S6 kinase also inhibited angiotensin II-stimulated neurotropic activity. These data confirm the involvement of PI3K and p70S6 kinase in angiotensin II-mediated neurotropic action. Further support for this was provided by the observation that angiotensin II caused a time-dependent stimulation of p70S6 kinase by an angiotensin type 1 receptor-mediated process. We also found that the neurotropic actions of angiotensin II are mediated by plasminogen activator inhibitor-1. Evidence for this includes 1) angiotensin II-stimulated neuronal plasminogen activator inhibitor-1 gene expression, 2) potent neurotropic action of exogenous plasminogen activator inhibitor-1, and 3) inhibitory neurotropic effect of angiotensin II by antisense oligonucleotide-mediated depletion of plasminogen activator inhibitor-1. Finally, we found that the neurotropic action of plasminogen activator inhibitor-1 is not blocked by either angiotensin type 1 receptor antagonist or inhibitors of PI3K or p70S6 kinase, indicating that the plasminogen activator inhibitor-1 step is downstream from the p70S6 kinase. These observations demonstrate that angiotensin II is a neurotropic hormone that engages a distinct PI3K-p70S6 kinase-plasminogen activator inhibitor-1 signaling pathway for this action.

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Induction of plasminogen activator inhibitor 1 by the PPARα ligand, Wy-14,643, is dependent on ERK1/2 signaling pathway

Thrombosis and Haemostasis ◽

10.1160/th03-01-0059 ◽

2003 ◽

Vol 90 (10) ◽

pp. 611-619 ◽

Cited By ~ 18

Author(s):

Cristina Banfi ◽

Johan Auwerx ◽

Federica Poma ◽

Elena Tremoli ◽

Luciana Mussoni

Keyword(s):

Plasminogen Activator ◽

Signaling Pathway ◽

Plasminogen Activator Inhibitor ◽

Luciferase Reporter ◽

Dependent Manner ◽

Plasminogen Activator Inhibitor 1 ◽

Luciferase Reporter Construct ◽

Pparγ Agonist ◽

Activator Inhibitor ◽

Pai 1

SummaryImpairment of the fibrinolytic system, mostly due to elevated plasma levels of plasminogen activator inhibitor 1 (PAI-1), is often associated with metabolic disorders such as diabetes mellitus and insulin-resistance syndrome. Moreover, insulin, as we have previously shown, directly stimulates PAI-1 production with a mechanism underlying a complex signaling network which ultimately leads to ERK activation.In this study we have analyzed the effects of agonists of the per-oxisome proliferator-activated receptor (PPAR) alpha and gamma on PAI-1 biosynthesis in HepG2 cells in the presence or absence of insulin. The high affinity PPARα agonist, Wy-14,643, increased basal and insulin-stimulated PAI-1 antigen release with a mechanism involving gene transcription. We then investigated whether the MAP kinase pathway also plays a role in the stimulatory properties of Wy-L4,643. Wy-L4,643 increases phosphorylation of ERK and p38 in a time-dependent manner without affecting that of SAPK/JNK or ERK5. Moreover, the MEK (ERK kinase) inhibitors, PD98059 and UO126, completely prevented PAI-1 induction by Wy-14,643 without inhibiting the activation of a reporter gene carrying the PPRE element. Interestingly, the addition of p38 inhibitor followed by insulin and Wy-14,643 resulted in a greater than additive stimulation of PAI-1 secretion acting through ERK1/2 phosphorylation.In contrast, the synthetic PPARγ agonist, rosiglitazone, did not change PAI-1 level, although this compound induced transcription from the PPRE-driven luciferase reporter construct.In conclusion, Wy-14,643 induces PAI-1 gene expression, in the presence or absence of insulin, with a mechanism which is independent on PPARα activation and requires signaling through the ERK1/2 signaling pathway.

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