three experiments (Figure 1). Myl9, was significantly downregu- lated at 30 mins (22.2 fold), highly upregulated at 3 days (4.6 fold), and upregulated at 7 days (2.9 fold). 40 other genes overlapped between 30 minutes and 3-days; 44 other genes overlapped between 3-day and 7-day injury; 74 genes overlapped between 3 minutes and 7-day injury. A comprehensive list of the overlapping genes is provided in Supplemental Table S1.A 2.0 fold change and p,.05 significance cut-offs were used. No multiple correction was employed. Age has a profound effect on genes differentially expressed after 30 minutes of wire injury in rats Vascular remodeling is highly sensitive to age. Therefore, to examine the effect of age on vascular remodeling using a common 30 minutes post-injury time, we studied the global gene expression in the iliac arteries of old versus young, old versus old, and young versus young rats. While most of the genes did not overlap among the 3 pairs compared, 12 genes overlapped in all the 3 experiments (Figure 2AB). These 12 genes can be considered not sensitive to the age effect but rather unique to the injury process. They include the Ca2+-dependent activator protein (Cadps2), the RNA binding motif protein (Rbm39), the neutrophil cytosolic factor (Ncf4), and the gap junction protein (Gja5). A comprehensive list of the Figure 1. Differentially expressed genes overlapping in multiple time points in old versus young injured rat iliac arteries. A. Venn diagram shows the number of differentially expressed genes determined by our analysis of 3 different time points in old versus young injured rat iliac arteries. Gene lists were compared to find common differentially expressed transcripts. A 2.0 fold change and p,.05 significance cut-offs were used. No multiple correction was employed. B. Heat map of Myl9 gene expression levels in multiple time points in old versus young injured rat iliac arteries. Myosin Light chain 9, Myl9, was significantly downregulated at 30 mins (22.2 fold), highly upregulated at 3 days (4.6 fold), and upregulated at 7 days (2.9 fold). Color bar shown in Log2. doi:10.1371/journal.pone.0025855.g001 Vascular Myl9 with Injury and Aging Figure 2. Differentially expressed genes overlapping in different age groups of 30 min-injured rat iliac arteries. A. Venn diagram shows lists of differentially expressed genes determined by our analysis of 3 different pairs of age groups of 30 min-injured rat iliac arteries. Gene lists were compared to find common differentially expressed transcripts. A 2.0 fold change and p,.05 significance cut-offs were used. No multiple correction was employed. B. Heat map of differentially expressed genes overlapping in different age groups of 30 min-injured rat iliac arteries.12 genes overlapped in old versus young, old versus old, and young versus young, 30 min-injured rat iliac arteries. Color bar shown in Log2. doi:10.1371/journal.pone.0025855.g002 overlapping genes between any 2 conditions is provided in Supplemental Table S2.A 2.0 fold change and p,.05 significance cut-offs were used. No multiple correction was employed. A common aging transcriptional profile in healthy rat iliac and aortic arteries includes Myl9 To investigate for a common aging transcriptional profile in healthy vessels, we compared global gene expression between 1) aged (22 months) versus young (3 months) rat iliac arteries, and 2) aged (28 months) versus young (3 months) rat thoracic aortas [8]. We found that 114 transcripts overlapped in the two studies (Figure 3A). Among these common transcripts were the contrac- tion genes Myl9 (Figure 3B) and Itga1 (Integrin alpha 1), which increased systematically with age in rat thoracic aortas (Figure 3B). As expected, collagens (Col1a1 and Col3a1) and vascular endothelial growth factor (Vegfa) were consistently downregulated, and the aging genes B-cell leukemia/lymphoma 2 (Bcl2) and vascular cell adhesion molecule 1 (Vcam1) were upregulated in both iliac and aortic arteries with age. In addition, NADPH oxidase 4 (Nox4) which is a positive regulator of SMC migration was also upregulated with age. A 2.0 fold change and p,.05 PLoS ONE | www.plosone.org 2 October 2011 | Volume 6 | Issue 10 | e25855