Abstract 603: O-GlcNAcylation of Runx2 is Essential for Vascular Calcification

Osteogenic differentiation of vascular smooth muscle cells (VSMC) contribute predominantly to vascular calcification, a characteristic of advanced atherosclerosis, chronic kidney disease, and diabetes. Using Runx2 shRNA and SMC-specific Runx2 deletion mice, we have demonstrated an essential role of Runx2 in regulating vascular calcification in vitro and in vivo. The present studies aim to pinpoint the Runx2 functional domain that is critical for its osteogenic function in VSMC and to elucidate the underlying molecular mechanisms. A series of Runx2 deletion mutants were generated and stably transfected into VSMC. Full-length Runx2 protein and Runx2 deletion mutants containing amino acids 1-495 or 1-432, but not Runx2 1-391, induced VMC calcification, indicating that the Runx2 osteogenic functional domain is located between amino acids 391-432. Site-directed mutagenesis analysis identified that mutations at the amino acids 412, 413, 425 and 426-428 markedly reduced Runx2 transactivity and inhibited Runx2-in...