Z Gastroenterol 2015; 53 - A1_36
DOI: 10.1055/s-0035-1567966

Shear-induced fibrillar-like supramolecule of plasma fibronectin: A new form of fibronectin with enhanced activity in platelet adhesion and aggregation

KC Huynh 4, H Nguyen 1, V Stoldt 1, RE Scharf 1
  • 1University of Düsseldorf, Department of Hemostasis, Hemotherapy, and Transfusion Medicine, Düsseldorf, Germany
  • 2University of Düsseldorf, NRW research school Biostruct, Düsseldorf, Germany
  • 3University of Düsseldorf, Biological Medical Research Center, Düsseldorf, Germany
  • 4International University, Vietnam National Universities – Ho Chi Minh City, Department of Biomedical Engineering, Ho Chi Minh, Vietnam

Background: We reported on the formation of fibronectin fibrils (FN fibrils) induced by shear rates.

Aims: Here, we characterized the function of shear-induced FN fibrils in platelet adhesion and aggregation.

Methods: For adhesion experiments, CMFDA labeled platelets were placed onto immobilized FN or FN fibrils (25 µg/ml) for 30 min at 37 °C. In parallel experiments, platelets resuspended in FN-depleted plasma were placed onto immobilized FN, collagen, or fibrinogen (10 µg/ml) in the presence of soluble FN (300 µg/ml) or FN fibrils (10 µg/ml). For aggregation experiments, FN (5, 10, 300 µg/ml) or FN fibrils (5, 10 µg/ml) was added to PRP or platelets resuspended in FN-depleted plasma. Aggregation was induced by 400 nM PMA, or 10 µg/ml collagen.

Results: The adhesion rates of washed platelets were higher onto surfaces coated with FN fibrils than with plasma FN. In parallel experiments using platelets resuspended in FN-depleted plasma, addition of plasma FN (300 µg/ml) increased platelet adhesion onto immobilized FN (from 0.14 ± 0.01 to 0.18 ± 0.02, p = 0.04), collagen (from 0.14 ± 0.005 to 0.2 ± 0.01, p = 0.0007), and fibrinogen (from 0.16 ± 0.03 to 0.22 ± 0.01). Addition of FN fibrils (10 µg/ml) had a similar supportive effect. Conversely, FN showed an inhibitory effect in platelet aggregation. Activation by PMA induced aggregation of PRP by 81%. In the presence of plasma FN at 5, 10, 300 µg/ml, platelet aggregation was reduced to 50%, 41%, and 29.5%, respectively. A stronger inhibition on platelet aggregation was seen with FN fibrils. PRP aggregated by 35.4% and 17% in the presence of 5 and 10 µg/ml FN fibrils, respectively. The same phenomenon was observed in aggregation assays using platelets resuspended in FN-depleted plasma and collagen as activating agonist.

Conclusion: Our study suggested that shear-induced FN fibrils have stronger activity in supporting platelet adhesion and inhibiting platelet aggregation than normal plasma FN. This finding emphasizes the importance of FN assembly on its activity in platelet function.

Corresponding author: Huynh, Khon

E-Mail: hckhon@hcmiu.edu.vn