Selective abrogation of the uPA-uPAR interaction in vivo reveals a novel role in suppression of fibrin-associated inflammation.

Abstract

The urokinase plasminogen activator receptor (uPAR) has emerged as a potential regulator of cell adhesion, cell migration, proliferation, differentiation, and cell survival in multiple physiologic and pathologic contexts. The urokinase plasminogen activator (uPA) was the first identified ligand for uPAR, but elucidation of the specific functions of the uPA-uPAR interaction in vivo has been difficult because uPA has important physiologic functions that are independent of binding to uPAR and because uPAR engages multiple ligands. Here, we developed a new mouse strain (Plau(GFDhu/GFDhu)) in which the interaction between endogenous uPA and uPAR is selectively abrogated, whereas other functions of both the protease and its receptor are retained. Specifically, we introduced 4 amino acid substitutions into the growth factor domain (GFD) of uPA that abrogate uPAR binding while preserving the overall structure of the domain. Analysis of Plau(GFDhu/GFDhu) mice revealed an unanticipated role of the uPA-uPAR interaction in suppressing inflammation secondary to fibrin deposition. In contrast, leukocyte recruitment and tissue regeneration were unaffected by the loss of uPA binding to uPAR. This study identifies a principal in vivo role of the uPA-uPAR interaction in cell-associated fibrinolysis critical for suppression of fibrin accumulation and fibrin-associated inflammation and provides a valuable model for further exploration of this multifunctional receptor.

• Authors: Brian M Connolly, Eun Young Choi, Henrik Gårdsvoll, Alexandra L Bey, Brooke M Currie, Triantafyllos Chavakis, Shihui Liu, Alfredo Molinolo, Michael Ploug, Stephen H Leppla, Thomas H Bugge
• Journal: Blood (Blood) Vol. 116 Issue 9 Pg. 1593-603 (Sep 02 2010) ISSN: 1528-0020 [Electronic] United States
• PMID: 20466854 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, N.I.H., Intramural, Research Support, Non-U.S. Gov't)

Chemical References

• RNA, Messenger
• Receptors, Urokinase Plasminogen Activator
• Fibrin
• Urokinase-Type Plasminogen Activator

Topics

• Animals
• Apoptosis
• Blotting, Western
• Cell Proliferation
• Disease Models, Animal
• Female
• Fibrin (metabolism)
• Flow Cytometry
• Fluorescent Antibody Technique
• Humans
• Immunoenzyme Techniques
• Inflammation (metabolism, pathology, prevention & control)
• Liver (immunology, injuries, metabolism)
• Lung Injury (immunology, metabolism, prevention & control)
• Macrophages, Peritoneal (immunology, metabolism, pathology)
• Male
• Mice
• Mice, Inbred C57BL
• Pneumonia (immunology, metabolism, prevention & control)
• RNA, Messenger (genetics)
• Receptors, Urokinase Plasminogen Activator (genetics, metabolism)
• Reverse Transcriptase Polymerase Chain Reaction
• Skin Diseases (immunology, metabolism, prevention & control)
• Survival Rate
• Urokinase-Type Plasminogen Activator (genetics, metabolism)
• Wound Healing