Fig. 5.
Thymine DNA glycosylase (TDG) is upregulated in vascular smooth muscle (VSM) synthetic phenotype (VSMSyn). A: diagram of a switch from a hypomethylated state in differential VSM (VSMDiff) to a hypermethylated state in VSMSyn cells following vascular injury or with vasculo-proliferative diseases. Oxidation of 5-methylcytosine (5-mC) by ten-eleven translocations (TETs) generates 5-hydroxymethylcytosine (5-hmc), 5-formylcytosine (5-fc), and 5-caC in VSMDiff. TDG is one prominent DNA damage repair factor capable of excising 5-fmC and 5-caC from DNA and can complex with DNA methyltransferase 3a/b to facilitate remethylation in VSMSyn. B: immunoblots (IB) of myosin heavy chain (MYH) 11, TDG, and GAPDH in rat aortic VSMDiff cells and cultured VSMSyn cells from 3 individual animals. C: quantitation of immunoblots in B. D: rat aorta medial layer VSM cells (VSMDiff) were enzymatically dispersed and cultured for 1–6 passages (VSMSyn). Quantitative PCR was employed to measure mRNA levels of Tdg, Myh11, and Gapdh in intact aorta and derived cells. Values were normalized over Gapdh and expressed as means ± SE. n = 3 different animals analyzed by unpaired t test for C or 2-way ANOVA for D. **P < 0.01 and ***P < 0.001.