Thrombin and NAD(P)H oxidase-mediated regulation of CD44 and BMP4-Id pathway in VSMC, restenosis, and atherosclerosis

To characterize novel signaling pathways that underlie NAD(P) H oxidase - mediated signaling in atherosclerosis, we first examined differences in thrombin-induced gene expression between wild-type and p47phox(-/-) ( NAD[ P] H oxidase - deficient) VSMC. Of the 9000 genes analyzed by cDNA microarray method at the G(1)/S transition point, 76 genes were similarly and significantly modulated in both the cell types, whereas another 22 genes that encompass various functional groups were regulated in NAD(P) H oxidase - dependent manner. Among these 22 genes, thrombin-induced NAD(P) H oxidase - mediated regulation of Klf15, Igbp1, Ak4, Adamts5, Ech1, Serp1, Sec61a2, Aox1, Aoh1, Fxyd5, Rai14, and Serpinh1 was shown for the first time in VSMC. The role of NAD( P) H oxidase in the regulation of a subset of these genes (CD44, BMP4, Id1, and Id3) was confirmed using modulators of reactive oxygen species (ROS) generation, a ROS scavenger and in gain-of-function experiments. We then characterized regulation of these genes in restenosis and atherosclerosis. In both apoE(-/-) mice and in a mouse vascular injury model, these genes are regulated in NAD(P) H oxidase - dependent manner during vascular lesion formation. Based on these findings, we propose that NAD(P) H oxidase - dependent gene expression in general, and the CD44 and BMP4-Id signaling pathway in particular, is important in restenosis and atherosclerosis.