Suv39h1 downregulation inhibits neointimal hyperplasia after vascular injury

Neointimal hyperplasia resulting from pathological vascular smooth muscle cells (VSMCs) activation is a common pathophysiological basis for numerous proliferative vascular diseases, such as restenosis. Suv39h1, an important transcription suppressor, may be involved in this process. Herein, we investigated the role of Suv39h1 in pathological intimal hyperplasia and its possible mechanisms in vitro and in vivo.

An adenovirus vector for Suv39h1 overexpression and a lentiviral vector for its downregulation were constructed and used to transfect cultured VSMCs in vitro. The functional changes in VSMCs stimulated by angiotensin II (Ang II) were observed and the possible mechanism was investigated. Additionally, rat carotid arteries with balloon injury were locally transfected with these viral vectors and changes in neointima formation, proliferating cell nuclear antigen (Pcna) expression and collagen deposition were examined.

Upon Ang II stimulation, the expression of Suv39h1 and inhibitor of DNA binding 3 (Id3) was significantly increased. Suv39h1 downregulation inhibited Ang II-stimulated migration and proliferation of VSMCs, antagonized the production of Id3 and promoted p21 and p27Kip1 expression. In contrast, Suv39h1 overexpression had the opposite effects. Suv39h1 regulated the transcription of p21 and p27Kip1 by controlling H3K9me3 in the proximal promoter regions. Consistent with the VSMCs results, Suv39h1 and Id3 expression was significantly increased in blood vessels after balloon injury. Suv39h1 downregulation inhibited intimal hyperplasia, and attenuated Pcna expression and collagen synthesis in the intima, while Suv39h1 overexpression had the opposite effects.

Suv39h1 downregulation effectively inhibited neointimal hyperplasia after vascular injury.