Zhang Mengxue, Li Jing, Wang Qingwei, Urabe Go, Tang Runze, Huang Yitao, Mosquera Jose Verdezoto, Kent K Craig, Wang Bowen, Miller Clint L, Guo Lian-Wang
Department of Surgery, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA.
Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA.
Mol Ther Nucleic Acids. 2023 Feb 21;31:717-729. doi: 10.1016/j.omtn.2023.02.024. eCollection 2023 Mar 14.
Epigenetically switched, proliferative vascular smooth muscle cells (SMCs) form neointima, engendering stenotic diseases. Histone-3 lysine-27 trimethylation (H3K27me3) and acetylation (H3K27ac) marks are associated with gene repression and activation, respectively. The polycomb protein embryonic ectoderm development (EED) reads H3K27me3 and also enhances its deposition, hence is a canonical gene repressor. However, herein we found an unexpected role for EED in activating the pro-proliferative gene (cyclinD1). EED overexpression in SMCs increased mRNA, seemingly contradicting its gene-repressing function. However, consistently, EED co-immunoprecipitated with gene-activating H3K27ac reader BRD4, and they co-occupied at both mitogen-activated and mitogen-repressed ( anti-proliferative gene), as indicated by chromatin immunoprecipitation qPCR. These results were abolished by an inhibitor of either the EED/H3K27me3 or BRD4/H3K27ac reader function. In accordance, elevating BRD4 increased H3K27me3. , while EED was upregulated in rat and human neointimal lesions, selective EED inhibition abated angioplasty-induced neointima and reduced cyclinD1 in rat carotid arteries. Thus, results uncover a previously unknown role for EED in activation, likely via its cooperativity with BRD4 that enhances each other's reader function; i.e., activating pro-proliferative while repressing anti-proliferative . As such, this study confers mechanistic implications for the epigenetic intervention of neointimal pathology.
表观遗传转换的增殖性血管平滑肌细胞（SMC）形成新内膜，引发狭窄性疾病。组蛋白H3赖氨酸27三甲基化（H3K27me3）和乙酰化（H3K27ac）标记分别与基因抑制和激活相关。多梳蛋白胚胎外胚层发育（EED）读取H3K27me3并增强其沉积，因此是一种典型的基因抑制因子。然而，我们在此发现EED在激活促增殖基因（细胞周期蛋白D1）方面具有意想不到的作用。SMC中EED的过表达增加了mRNA，这似乎与其基因抑制功能相矛盾。然而，一致的是，EED与基因激活的H3K27ac读取器BRD4共免疫沉淀，并且它们在有丝分裂原激活和有丝分裂原抑制（抗增殖基因）时共同占据，染色质免疫沉淀qPCR表明了这一点。EED/H3K27me3或BRD4/H3K27ac读取器功能的抑制剂消除了这些结果。相应地，升高BRD4会增加H3K27me3。此外，在大鼠和人类新内膜病变中EED上调，选择性EED抑制减轻了血管成形术诱导的新内膜，并降低了大鼠颈动脉中的细胞周期蛋白D1。因此，结果揭示了EED在激活中的一个先前未知的作用，可能是通过其与BRD4的协同作用，增强彼此的读取器功能；即激活促增殖基因同时抑制抗增殖基因。因此，本研究为新内膜病理学的表观遗传干预提供了机制方面的启示。
