Figure 1
Carotid injury induces YY1 expression and inhibits SMC differentiation. (A–D) Mouse carotid arteries were ligated for two weeks. (A,B) Representative IHC images show that YY1 expression is low in the uninjured right carotid artery (Control, RCA) and injury induces YY1 expression in the neointima-media layer of the injured left carotid artery (Injury, LCA). The YY1 antigen positive signal is increased in the injury-induced neointima-media layer between the lumen and the adventitia. The black dots indicate the border between media and adventitia of the vessel wall. The adjacent section incubated with the secondary antibody (2nd Ab) alone serves as the negative control. The arrow indicates the same position in the media layer SMCs on two adjacent sections. Scale bar: 200 μm (10X); 50 μm (40X). (C) Quantification of positive IHC signals in the neointima-media layer of the vessel wall. n = 4. (D) qRT-PCR assays show increased expression of YY1 and decreased expression of SMC differentiation markers in injured carotid arteries. n = 6. (E,F) Rat carotid arteries after balloon injury for 3 or 7 days. (E) qRT-PCR assays show increased expression of YY1 in response to injury. n = 6. (F) Western blot assays show increased expression of YY1 and decreased expression of SMC differentiation markers SMMHC, SM22α and SMα-actin in the injured carotid arteries. Quantification of band density is shown on the right. n = 3. Vinculin serves as the loading control for WB. The uncropped original blots are presented in Supplementary Figure S3. All quantification data are presented as mean ± SEM. *P < 0.05 versus control.
