Gene-repressing epigenetic reader EED unexpectedly enhances cyclinD1 gene activation

Mengxue Zhang; Jing Li; Qingwei Wang; Go Urabe; Runze Tang; Yitao Huang; Jose Verdezoto Mosquera; K Craig Kent; Bowen Wang; Clint L Miller; Lian-Wang Guo

doi:10.1016/j.omtn.2023.02.024

Gene-repressing epigenetic reader EED unexpectedly enhances cyclinD1 gene activation

Mol Ther Nucleic Acids. 2023 Feb 21:31:717-729. doi: 10.1016/j.omtn.2023.02.024. eCollection 2023 Mar 14.

Authors

Mengxue Zhang¹, Jing Li¹, Qingwei Wang¹, Go Urabe¹, Runze Tang¹, Yitao Huang¹, Jose Verdezoto Mosquera^{2

3}, K Craig Kent¹, Bowen Wang¹, Clint L Miller^{2

3

4

5}, Lian-Wang Guo^{1

5

6}

Affiliations

¹ Department of Surgery, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA.
² Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA.
³ Center for Public Health Genomics, University of Virginia, Charlottesville, VA 22908, USA.
⁴ Department of Public Health Sciences, University of Virginia, Charlottesville, VA 22908, USA.
⁵ Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA.
⁶ Department of Molecular Physiology and Biological Physics, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA.

Abstract

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 bona fide pro-proliferative gene Ccnd1 (cyclinD1). EED overexpression in SMCs increased Ccnd1 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 Ccnd1 and mitogen-repressed P57 (bona fide 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. In vivo, 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 Ccnd1 activation, likely via its cooperativity with BRD4 that enhances each other's reader function; i.e., activating pro-proliferative Ccnd1 while repressing anti-proliferative P57. As such, this study confers mechanistic implications for the epigenetic intervention of neointimal pathology.

Keywords: BRD4 in p57 repression; EED in Ccnd1 activation; MT: Oligonucleotides: Therapies and Applications; cooperativity between EED and BRD4; epigenetic readers; neointima; smooth muscle cell proliferation.