| First Author | Otsuka G | Year | 2007 |
| Journal | Circ Res | Volume | 100 |
| Issue | 9 | Pages | 1300-7 |
| PubMed ID | 17431190 | Mgi Jnum | J:137777 |
| Mgi Id | MGI:3802871 | Doi | 10.1161/01.RES.0000266970.34017.8d |
| Citation | Otsuka G, et al. (2007) Mechanisms of TGF-beta1-induced intimal growth: plasminogen-independent activities of plasminogen activator inhibitor-1 and heterogeneous origin of intimal cells. Circ Res 100(9):1300-7 |
| abstractText | Transforming growth factor (TGF)-beta(1) is a potent stimulator of intimal growth. We showed previously that TGF-beta(1) stimulates intimal growth through early upregulation of plasminogen activator inhibitor-1 (PAI-1) and, subsequently, PAI-1-dependent increases in cell migration and matrix accumulation. We also showed that PAI-1 negatively regulates TGF-beta(1) expression in the artery wall. Here we use plasminogen-deficient mice to test whether TGF-beta(1)-stimulated, PAI-1-dependent intimal growth and PAI-1 suppression of TGF-beta(1) expression are mediated through inhibition of plasminogen activation by PAI-1. We also use lineage tracing to investigate the origin of cells in TGF-beta(1)-induced intimas. Surprisingly, both TGF-beta(1)-induced, PAI-1-dependent intimal growth and PAI-1 suppression of TGF-beta(1) expression are independent of plasminogen. Moreover, approximately 50% of cells that migrate into the intima of TGF-beta(1)-overexpressing arteries carry a smooth muscle lineage marker, <1% carry a bone marrow lineage marker, and the remaining cells carry neither marker. Therefore, PAI-1 stimulates intimal growth and suppresses TGF-beta(1) expression through activities other than inhibition of plasminogen activation. In addition, contrary to widely held models, our results do not support a role for plasmin (or thrombospondin) in TGF-beta(1) activation in the artery wall. Further identification of the molecular targets through which PAI-1 stimulates intimal formation and suppresses TGF-beta(1) expression in the artery wall may reveal new approaches for inhibiting intimal formation. Our studies also discount bone marrow as an important source from which TGF-beta(1) recruits intimal cells and suggest instead that TGF-beta(1) induces substantial cell migration either from the adventitia or from an extravascular, but nonhematopoietic source. |
