The underlying cause of all vascular proliferative diseases is injury-induced activation of vascular endothelium and vascular smooth muscle cells (VSMC). Activated VSMC proliferate, than migrate from the arterial media to the intima, contributing to neointima formation. Activated immune cells, vascular cells, and their endogenous regulators mediate this complex process. One integral regulator of VSMC activation is allograft inflammatory factor-1 (AIF-1). AIF-1 is a cytoplasmic scaffold protein,

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... expressed constitutively in lymphoid cells and induced in VSMC by injury. Stable over expression of AIF-1 increases VSMC proliferation and migration in vitro, causes increased injury-induced neointima formation, and increases Rac1 and p38 MAP Kinase activity. Recent studies show a correlation between VSMC expression of AIF-1 and atherosclerosis development. We hypothesize that VSMC over expression of AIF-1 contributes to atherosclerosis development by increasing activity of inflammatory signaling molecules, and that inhibiting VSMC AIF-1 expression will decrease injury-induced neointima formation. Rat carotid arteries transfected with AIF-1 si RNA adenovirus after balloon angioplasty developed significantly less neointima compared to controls. AIF-1 si RNA transfected VSMC proliferated significantly less than AIF-1 or GFP transfected VSMC, while AIF-1 si RNA transfection did not attenuate AIF-1-mediated migration. p38 inhibition showed that AIF-1-mediated proliferation is dependent on p38 activation while AIF-1-mediated migration is not. AIF-1 transgenic mice fed a high fat diet showed significantly more atherosclerotic lesions than WT littermates. Boyden Chamber assays showed OxLDL treatment increases VSMC migration but does not effect AIF-1-mediated migration. Expression of migration and inflammatory responsive genes in AIF-1 and XGal transfected VSMC after OxLDL treatment at various time points were examined. MMP-2 and -9 expression did not change. ICAM-1 and VCAM-1 expression increased in both groups. AIF-1 VSMC showed [...]