Department of Cardiology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, China.
Department of Cardiology, Changhai Hospital, Naval Medical University, Shanghai, China.
J Cell Physiol. 2021 Jul;236(7):5421-5431. doi: 10.1002/jcp.30248. Epub 2020 Dec 28.
The excessive proliferation and migration of vascular smooth muscle cells (VSMCs) play vital roles in neointimal hyperplasia and vascular restenosis. In the present study, we aimed to investigate the function and mechanism of octamer-binding transcription factor 4 (OCT4, a key transcription factor for maintaining stem cells in de-differentiated state) on neointima formation in response to vascular injury. Quantitative reverse-transcription polymerase chain reaction and western blot results displayed a significant increase of OCT4 levels in injured carotid arteries. Immunohistochemistry and immunofluorescence assays confirmed that the increased OCT4 expression was primarily localized in α-SMA-positive VSMCs from neointima, and colocalized with PCNA in the nuclei of VSMCs. Adenovirus-mediated OCT4 overexpression in injured carotid arteries exacerbated intimal thickening, while OCT4 knockdown significantly inhibited intimal thickening. In-vitro experiments confirmed that the increased OCT4 expression in VMSCs could be induced by platelet-derived growth factor-BB (PDGF-BB) in a time-dependent manner. Overexpression of OCT4 greatly promoted VSMCs proliferation and migration, while OCT4 knockdown significantly retarded the PDGF-BB-induced excessive proliferation and migration of VSMCs. Bioinformatics analysis, dual-luciferase reporter assay, and chromatin immunoprecipitation assay confirmed that OCT4 could upregulate matrix metalloproteinases 2 (MMP2) expression through promoting its transcription. Moreover, knockdown of MMP2 significantly attenuated OCT4-mediated VSMCs proliferation and migration. These results indicated that OCT4 facilitated neointimal formation in response to vascular injury by MMP2-mediated VSMCs proliferation and migration, and targeting OCT4 in VSMCs might be a novel therapeutic strategy for vascular restenosis.
血管平滑肌细胞（VSMCs）的过度增殖和迁移在新生内膜增生和血管再狭窄中起着至关重要的作用。在本研究中，我们旨在研究八聚体结合转录因子 4（OCT4，一种维持去分化状态下干细胞的关键转录因子）在血管损伤后对新生内膜形成的作用和机制。定量逆转录聚合酶链反应和 Western blot 结果显示，损伤颈动脉中 OCT4 水平显著增加。免疫组织化学和免疫荧光检测证实，OCT4 表达的增加主要位于新生内膜中 α-SMA 阳性的 VSMCs 中，并与 VSMCs 核中的 PCNA 共定位。腺病毒介导的 OCT4 在损伤颈动脉中的过表达加剧了内膜增厚，而 OCT4 敲低则显著抑制了内膜增厚。体外实验证实，血小板衍生生长因子-BB（PDGF-BB）可在时间依赖性方式诱导 VMSCs 中 OCT4 表达增加。OCT4 的过表达可显著促进 VSMCs 的增殖和迁移，而 OCT4 的敲低则显著抑制 PDGF-BB 诱导的 VSMCs 的过度增殖和迁移。生物信息学分析、双荧光素酶报告基因检测和染色质免疫沉淀检测证实，OCT4 可通过促进 MMP2 的转录来上调其表达。此外，MMP2 的敲低显著减弱了 OCT4 介导的 VSMCs 增殖和迁移。这些结果表明，OCT4 通过 MMP2 介导的 VSMCs 增殖和迁移促进血管损伤后新生内膜形成，靶向 VSMCs 中的 OCT4 可能是血管再狭窄的一种新的治疗策略。
