Division of Cardiology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Tao-Yuan, Taiwan.
Department of Respiratory Therapy, Chang Gung University College of Medicine, Tao-Yuan, Taiwan.
Atherosclerosis. 2020 Dec;315:43-54. doi: 10.1016/j.atherosclerosis.2020.11.009. Epub 2020 Nov 8.
Uremic patients are characterized by an increased risk of atherosclerotic cardiovascular diseases. Vascular smooth muscle cell (VSMC) proliferation contributes to neointimal formation, a main pathological feature in atherosclerosis. Activation of CREB/ATF3 signaling is pivotal in VSMC proliferation, yet its role in uremic atherosclerosis is unknown. This study aimed to explore whether CREB/ATF3 signaling is involved in the molecular mechanism underlying neointimal formation in uremia.
Treatment of VSMCs with uremic toxin (indoxyl sulfate [IS]) activated cAMP/CREB/ATF3/cyclin D signaling, which was reflected by increased VSMC proliferation. Blocking cAMP/PKA/CREB/ATF3 signaling attenuated the promoting effect of IS on cyclin D1 expression and VSMC proliferation. Loss-of-function and time-dependent experiments showed that ATF3 lies downstream of the CREB signaling. Mutational analysis of cyclin D1 promoter along with chromatin immunoprecipitation assays showed that CREB/ATF3 signaling participated in IS-induced cyclin D transcription. In vivo, phosphorylated CREB (an active form of CREB) and ATF3 were prominently upregulated in the neointima of experimental uremic rats, the atherosclerotic plaques of uremic ApoE mice, and the iliac arteries of uremic patients. Notably, the use of lentivirus to knock down ATF3 in the neointima of balloon-injured arteries could suppress the effect of uremia in vivo, including neointimal formation and cyclin D expression.
In this study, we demonstrated that CREB/ATF3-related signaling may be involved in IS-induced VSMC proliferation and the pathogenesis of neointimal formation during uremia.
尿毒症患者的动脉粥样硬化性心血管疾病风险增加。血管平滑肌细胞（VSMC）增殖导致新生内膜形成，这是动脉粥样硬化的主要病理特征。CREB/ATF3 信号的激活在 VSMC 增殖中起着关键作用，但它在尿毒症性动脉粥样硬化中的作用尚不清楚。本研究旨在探讨 CREB/ATF3 信号是否参与尿毒症中新内膜形成的分子机制。
尿毒症毒素（吲哚硫酸酯[IS]）处理 VSMC 激活了 cAMP/CREB/ATF3/细胞周期蛋白 D 信号通路，这反映在 VSMC 增殖增加。阻断 cAMP/PKA/CREB/ATF3 信号通路减弱了 IS 对细胞周期蛋白 D1 表达和 VSMC 增殖的促进作用。失能和时间依赖性实验表明，ATF3 位于 CREB 信号的下游。细胞周期蛋白 D1 启动子的突变分析以及染色质免疫沉淀实验表明，CREB/ATF3 信号参与了 IS 诱导的细胞周期蛋白 D 转录。在体内，实验性尿毒症大鼠新生内膜、尿毒症 ApoE 小鼠动脉粥样硬化斑块和尿毒症患者髂动脉中磷酸化 CREB（CREB 的活性形式）和 ATF3 明显上调。值得注意的是，使用慢病毒在球囊损伤动脉的新生内膜中敲低 ATF3 可抑制尿毒症的体内作用，包括新生内膜形成和细胞周期蛋白 D 表达。
在这项研究中，我们证明了 CREB/ATF3 相关信号可能参与 IS 诱导的 VSMC 增殖和尿毒症中新内膜形成的发病机制。
