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This Article Full Text Full Text (PDF) All Versions of this Article: 297/3/C759    most recent 00213.2009v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Vesely, E. D. Articles by Brosius, F. C. PubMed PubMed Citation Articles by Vesely, E. D. Articles by Brosius, F. C., III

GROWTH, DIFFERENTIATION, AND APOPTOSIS

GLUT1-induced cFLIP expression promotes proliferation and prevents apoptosis in vascular smooth muscle cells

Departments of ¹Internal Medicine and ²Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan; and ³University of Florida College of Medicine, Jacksonville, Florida

Submitted 13 May 2009 ; accepted in final form 1 July 2009

Enhanced expression of the facilitative glucose transporter, GLUT1, has been shown to inhibit apoptosis in several cell systems including vascular smooth muscle cells (VSMCs). A decrease in apoptosis could lead to increased VSMC numbers in neointimal and medial arterial layers under several pathologic conditions. The hypothesis underlying these studies is that GLUT1 induces expression of antiapoptotic and prosurvival genes that increase VSMC survival. Transcriptomic analysis of A7r5 VSMCs, in which GLUT1 was acutely overexpressed, showed a 2.14-fold increase in c-FLICE inhibitory protein (cFLIP), which promotes cellular growth and prevents apoptosis through caspase 8 binding. We confirmed that overexpression of GLUT1 induced mRNA and protein expression of both the long and short isoforms of cFLIP (cFLIP_L and cFLIP_S) in primary and stable immortalized VSMC lines as well as in aortas from GLUT1 transgenic mice. Increased GLUT1 reduced VSMC death by more than twofold after serum withdrawal, as evidenced by decreased caspase 3 activity and Trypan blue exclusion studies. GLUT1 overexpression resulted in a greater than twofold increase in proliferating cell nuclear antigen expression and live cell numbers, consistent with augmented VSMC proliferation. Lentiviral knockdown of cFLIP_L showed that cFLIP_L was necessary for the proproliferative and antiapoptotic effects of GLUT1 overexpression. Taken together, these data suggest that GLUT1 induction of cFLIP_L expression augments proliferation and prevents apoptosis in VSMCs.

metabolism; glucose; neointimal hyperplasia; c-FLICE inhibitory protein