Biomedical subjects

Cristina Lupu

Publications and source records attributed to Cristina Lupu.

3 recordsLinked to original sources

PubMed2006

Adenovirus-mediated expression of tissue factor pathway inhibitor-2 inhibits endothelial cell migration and angiogenesis.

OBJECTIVE: Extracellular matrix (ECM) remodeling during angiogenesis is accomplished through plasmin-dependent pericellular proteolysis and through the action of matrix metalloproteinases (MMPs). Because tissue factor pathway inhibitor-2 (TFPI-2), a Kunitz-type protease inhibitor with prominent ECM localization, inhibits plasmin and MMPs activity, we investigated the role of TFPI-2 in endothelial cell (EC) migration and angiogenesis. METHODS AND RESULTS: Real-time polymerase chain reaction and immunostaining showed that the expression of TFPI-2 mRNA and protein was upregulated in migrating ECs. The effect of TFPI-2 on angiogenesis was studied in mouse models of Matrigel and polyvinylalcohol sponge implants by overexpressing TFPI-2 through infection with a replication-deficient adenovirus (AdTFPI-2). Using (immuno)fluorescence and confocal microscopy we observed that TFPI-2 reduced neovascularization and promoted ECM deposition. Lateral cell migration and capillary tube formation in vitro also were impaired by TFPI-2, a process reversed by anti-TFPI-2 antibodies. Increased apoptosis occurred both in AdTFPI-2-treated ECs and in the mouse implants. Zymography and assays in the absence of plasminogen confirmed plasmin inhibition as a main mechanism through which TFPI-2 inhibits EC migration. CONCLUSIONS: Our data suggest that TFPI-2 may be an important regulator of aberrant angiogenesis associated with tumor growth/metastasis, cardiovascular diseases, chronic inflammation, or diabetes.

Adenoviridae↗

PubMed2005

Caveolin-1 enhances tissue factor pathway inhibitor exposure and function on the cell surface.

Tissue factor pathway inhibitor (TFPI) blocks tissue factor-factor VIIa (TF-FVIIa) activation of factors X and IX through the formation of the TF-FVIIa-FXa-TFPI complex. Most TFPI in vivo associates with caveolae in endothelial cells (EC). The mechanism of this association and the anticoagulant role of caveolar TFPI are not yet known. Here we show that expression of caveolin-1 (Cav-1) in 293 cells keeps TFPI exposed on the plasmalemma surface, decreases the membrane lateral mobility of TFPI, and increases the TFPI-dependent inhibition of TF-FVIIa. Caveolae-associated TFPI supports the co-localization of the quaternary complex with caveolae. To investigate the significance of these observations for EC we used RNA interference to deplete the cells of Cav-1. Functional assays and fluorescence microscopy revealed that the inhibitory properties of TFPI were diminished in EC lacking Cav-1, apparently through deficient assembly of the quaternary complex. These findings demonstrate that caveolae regulate the inhibition by cell-bound TFPI of the active protease production by the extrinsic pathway of coagulation.

Blotting, Western↗

PubMed2005

Tissue factor-dependent coagulation is preferentially up-regulated within arterial branching areas in a baboon model of Escherichia coli sepsis.

Endothelium plays a critical role in the pathobiology of sepsis by integrating systemic host responses and local rheological stimuli. We studied the differential expression and activation of tissue factor (TF)-dependent coagulation on linear versus branched arterial segments in a baboon sepsis model. Animals were injected intravenously with lethal doses of Escherichia coli or saline and sacrificed after 2 to 8 hours. Whole-mount arterial segments were stained for TF, TF-pathway inhibitor (TFPI), factor VII (FVII), and markers for endothelial cells (ECs), leukocytes, and platelets, followed by confocal microscopy and image analysis. In septic animals, TF localized preferentially at branches, EC surface, leukocytes, and platelet aggregates and accumulated in large amounts in the subendothelial space. FVII strongly co-localized with TF on ECs and leukocytes but less so with subendothelial TF. TFPI co-localized with TF and FVII on endothelium and leukocytes but not in the subendothelial space. Focal TF increases correlated with fibrin deposition and increased endothelial permeability to plasma proteins. Biochemical analysis confirmed that aortas of septic baboons expressed more TF mRNA and protein than controls. Branched segments contained higher TF protein levels and coagulant activity than equivalent linear areas. These data suggest that site-dependent endothelial heterogeneity and rheological factors contribute to focal procoagulant responses to E. coli.

Animals↗