Aim Estrogen exerts beneficial cardiovascular effects by binding to specific receptors on various cells to activate nuclear and non-nuclear actions. Estrogen receptor α (ERα) non-nuclear signaling confers protection against heart failure remodeling, involving myocardial cyclic guanosine monophosphate (cGMP) - cGMP-dependent protein kinase G (PKG) activation; however, its tissue-specific role remains elusive. Herein, we examined the cell type-specific role of ERα non-nuclear signaling in estrogen-conferred protection against heart failure. Methods and results We first assessed the tissue-specific impacts of ERα in estrogen’s cardiac benefits, utilizing endothelial ERα deletion (ERαf/f/Tie2Cre+) and myocyte ERα deletion (ERαf/f/αMHCCre+) female mice. Female mice were ovariectomized and the effect of estradiol (E2) was assessed in hearts exposed to 3week pressure-overload (TAC). E2 failed to improve cardiac function in ERαf/f/Tie2Cre+ TAC hearts but provided benefits in ERαf/f/αMHCCre+ TAC hearts, indicating that endothelial ERα is essential. We next assessed the role of non-nuclear signaling in endothelial cells, employing animals with endothelial-specific inactivation of ERα non-nuclear signaling (ERαKI/KI/Tie2Cre+). Female OVX mice were supplemented with E2 and subjected to 3-week TAC. ERαKI/KI/Tie2Cre+ TAC hearts revealed exacerbated cardiac dysfunction and reduced myocardial PKG activity as compared to littermate TAC hearts, which was associated with attenuated myocardial induction of vascular endothelial growth factor (VEGF) and angiogenesis as assessed with CD31-stained capillary density. This phenotype of ERαKI/KI/Tie2Cre+ was rescued by myocardial PKG activation from chronic treatment with soluble guanylate cyclase (sGC) stimulator. We performed co-culture experiments to determine endothelial-cardiomyocyte interactions. VEGF induction by E2 in cardiac myocytes required co-existence of intact endothelial ERα signaling in a NOS-dependent manner. On the other hand, VEGF was induced in myocytes directly with an sGC stimulator in the absence of endothelial cells. Conclusions An endothelial estrogen - myocardial cGMP axis stimulates angiogenic response and improves cardiac performance during pressure-overload.

中文翻译：

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内皮雌激素 - 心肌 cGMP 轴关键决定压力超负荷期间的血管生成和心脏性能


目的 雌激素通过与各种细胞上的特定受体结合来激活核和非核作用，从而发挥有益的心血管作用。雌激素受体 α (ERα) 非核信号传导可防止心力衰竭重塑，涉及心肌环磷酸鸟苷 (cGMP) - cGMP 依赖性蛋白激酶 G (PKG) 激活；然而，其组织特异性作用仍然难以捉摸。在此，我们检查了 ERα 非核信号传导在雌激素赋予的心力衰竭保护中的细胞类型特异性作用。方法和结果我们首先利用内皮 ERα 缺失 (ERαf/f/Tie2Cre+) 和肌细胞 ERα 缺失 (ERαf/f/αMHCCre+) 雌性小鼠评估 ERα 对雌激素心脏益处的组织特异性影响。雌性小鼠被切除卵巢，并评估雌二醇 (E2) 对暴露于 3 周压力超负荷 (TAC) 的心脏的影响。 E2 未能改善 ERαf/f/Tie2Cre+ TAC 心脏的心脏功能，但对 ERαf/f/αMHCCre+ TAC 心脏有好处，表明内皮 ERα 至关重要。接下来，我们使用内皮特异性 ERα 非核信号传导 (ERαKI/KI/Tie2Cre+) 失活的动物来评估非核信号传导在内皮细胞中的作用。雌性 OVX 小鼠补充 E2 并接受为期 3 周的 TAC。与同窝 TAC 心脏相比，ERαKI/KI/Tie2Cre+ TAC 心脏显示心脏功能障碍加剧，心肌 PKG 活性降低，这与血管内皮生长因子 (VEGF) 的心肌诱导减弱和用 CD31 染色的毛细血管密度评估的血管生成有关。 ERαKI/KI/Tie2Cre+ 的这种表型可以通过可溶性鸟苷酸环化酶 (sGC) 刺激剂长期治疗中心肌 PKG 激活来挽救。 我们进行了共培养实验来确定内皮-心肌细胞的相互作用。 E2 在心肌细胞中诱导 VEGF 需要完整内皮 ERα 信号以 NOS 依赖性方式共存。另一方面，在没有内皮细胞的情况下，用 sGC 刺激剂直接在肌细胞中诱导 VEGF。结论 内皮雌激素-心肌 cGMP 轴可刺激血管生成反应并改善压力超负荷期间的心脏功能。