Nuclear translocation of urokinase/nucleolin complexes

University Of Pennsylvania, Philadelphia PA

Investigators

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Abstract

[unreadable] DESCRIPTION (provided by applicant): Vascular remodeling is an essential component in the pathogenesis of atherosclerosis and other prevalent cardiovascular disorders, such as aneurysm formation, restenosis, and hypertension. The involvement of plasminogen activator (PA)/plasmin system in atherogenesis is well established through multiple studies that demonstrate overexpression of uPA, tPA and their inhibitor PAI-1 in human athrosclerosis. uPA and its surface receptor (uPAR) are implicated in vascular SMC proliferation/migration and matrix synthesis, which is pivotal in the progression of atherosclerosis. Our studies are the first to indicate that scuPA is translocated to the nucleus of mammalian cells in vitro and in vivo and we have identified one critical intermediary in the process, nucleolin. The issue we propose to address in this application is to delineate how uPA functions within the nucleus with the long-term goal of relating nuclear translocation and gene transcription to uPA-mediated alterations in cell adhesivity, proliferation and migration in vascular remodeling and atherosclerosis. Using Affymetrix DNA microarray, we have identified at least 6 genes relevant to vascular remodeling that are induced by uPA in nucleolin-dependent manner. In Aim 1, we propose to validate these microarray findings in coronary arterial SMC using RT-PCR and western blotting to provide a biological underpinning for what follows. In Aim 2 we will follow results already obtained from transcription factor (TF) arrays and use a mammalian two-hybrid system to determine whether scuPA or nucleolin bind directly to these or other TFs or to novel partners that regulate nuclear transport or transcription. In Aim 3, we will explore an alternative and novel mechanism by asking whether uPA regulates transcription by binding directly to DNA and/or gene promoters. Together these studies will elucidate a new facet of uPA biology and should provide an opportunity to develop specific means to regulate uPA- mediated pathologic processes. This knowledge will help to identify novel therapeutic approaches to prevent cell invasion and growth in vascular remodeling. This project intends to investigate how urokinase-type plasminogen activator uPA) stimulates gene expression, proliferation and migration in vascular SMC. These studies will reveal a novel pathway and novel targets to interrupt pathogenic intimal SMC migration in atherosclerosis and other common human vascular disorders as well as in progression of many human tumors. [unreadable] [unreadable] [unreadable]