Background:Many patients with heart failure with preserved ejection fraction have metabolic syndrome and develop exercise-induced pulmonary hypertension (EIPH). Increases in pulmonary vascular resistance in patients with heart failure with preserved ejection fraction portend a poor prognosis; this phenotype is referred to as combined precapillary and postcapillary pulmonary hypertension (CpcPH). Therapeutic trials for EIPH and CpcPH have been disappointing, suggesting the need for strategies that target upstream mechanisms of disease. This work reports novel rat EIPH models and mechanisms of pulmonary vascular dysfunction centered around the transcriptional repression of the soluble guanylate cyclase (sGC) enzyme in pulmonary artery (PA) smooth muscle cells.Methods:We used obese ZSF-1 leptin-receptor knockout rats (heart failure with preserved ejection fraction model), obese ZSF-1 rats treated with SU5416 to stimulate resting pulmonary hypertension (obese+sugen, CpcPH model), and lean ZSF-1 rats (controls). Right and left ventricular hemodynamics were evaluated using implanted catheters during treadmill exercise. PA function was evaluated with magnetic resonance imaging and myography. Overexpression of nuclear factor Y α subunit (NFYA), a transcriptional enhancer of sGC β1 subunit (sGCβ1), was performed by PA delivery of adeno-associated virus 6. Treatment groups received the SGLT2 inhibitor empagliflozin in drinking water. PA smooth muscle cells from rats and humans were cultured with palmitic acid, glucose, and insulin to induce metabolic stress.Results:Obese rats showed normal resting right ventricular systolic pressures, which significantly increased during exercise, modeling EIPH. Obese+sugen rats showed anatomic PA remodeling and developed elevated right ventricular systolic pressure at rest, which was exacerbated with exercise, modeling CpcPH. Myography and magnetic resonance imaging during dobutamine challenge revealed PA functional impairment of both obese groups. PAs of obese rats produced reactive oxygen species and decreased sGCβ1 expression. Mechanistically, cultured PA smooth muscle cells from obese rats and humans with diabetes or treated with palmitic acid, glucose, and insulin showed increased mitochondrial reactive oxygen species, which enhanced miR-193b–dependent RNA degradation of nuclear factor Y α subunit (NFYA), resulting in decreased sGCβ1-cGMP signaling. Forced NYFA expression by adeno-associated virus 6 delivery increased sGCβ1 levels and improved exercise pulmonary hypertension in obese+sugen rats. Treatment of obese+sugen rats with empagliflozin improved metabolic syndrome, reduced mitochondrial reactive oxygen species and miR-193b levels, restored NFYA/sGC activity, and prevented EIPH.Conclusions:In heart failure with preserved ejection fraction and CpcPH models, metabolic syndrome contributes to pulmonary vascular dysfunction and EIPH through enhanced reactive oxygen species and miR-193b expression, which downregulates NFYA-dependent sGCβ1 expression. Adeno-associated virus–mediated NFYA overexpression and SGLT2 inhibition restore NFYA-sGCβ1-cGMP signaling and ameliorate EIPH.

中文翻译：

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代谢综合征介导 ROS-miR-193b-NFYA 依赖性可溶性鸟苷酸环化酶下调，并导致射血分数保留的心力衰竭患者运动诱发的肺动脉高压


背景：许多射血分数保留的心力衰竭患者患有代谢综合征并出现运动性肺动脉高压（EIPH）。射血分数保留的心力衰竭患者肺血管阻力增加预示着预后不良；这种表型被称为毛细血管前和毛细血管后联合肺动脉高压（CpcPH）。 EIPH 和 CpcPH 的治疗试验令人失望，这表明需要针对疾病上游机制的策略。这项工作报告了新型大鼠 EIPH 模型和肺血管功能障碍的机制，主要围绕肺动脉 (PA) 平滑肌细胞中可溶性鸟苷酸环化酶 (sGC) 的转录抑制。方法：我们使用肥胖 ZSF-1 瘦素受体敲除大鼠（射血分数保留的心力衰竭模型）、用 SU5416 治疗以刺激静息肺动脉高压的肥胖 ZSF-1 大鼠（肥胖+sugen，CpcPH 模型）和瘦 ZSF-1 大鼠（对照）。在跑步机运动期间使用植入导管评估右心室和左心室血流动力学。 PA 功能通过磁共振成像和肌动描记法进行评估。通过 PA 递送腺相关病毒 6 来过度表达核因子 Y α 亚基 (NFYA)（sGC β1 亚基 (sGCβ1) 的转录增强子）。治疗组在饮用水中接受 SGLT2 抑制剂恩格列净。用棕榈酸、葡萄糖和胰岛素培养大鼠和人类的 PA 平滑肌细胞，以诱导代谢应激。结果：肥胖大鼠表现出正常的静息右心室收缩压，在运动期间显着升高，模拟 EIPH。 肥胖+sugen 大鼠表现出解剖学 PA 重塑，并在静息时出现右心室收缩压升高，运动时这种情况会加剧，从而模拟了 CpcPH。多巴酚丁胺激发期间的肌电图和磁共振成像显示两个肥胖组的 PA 功能受损。肥胖大鼠的 PA 产生活性氧并降低 sGCβ1 表达。从机制上讲，从肥胖大鼠和患有糖尿病的人中培养的 PA 平滑肌细胞或用棕榈酸、葡萄糖和胰岛素处理后显示线粒体活性氧含量增加，从而增强了核因子 Y α 亚基 (NFYA) 的 miR-193b 依赖性 RNA 降解，导致 sGCβ1-cGMP 信号传导减少。通过腺相关病毒 6 递送强制 NYFA 表达可增加肥胖+sugen 大鼠的 sGCβ1 水平并改善运动性肺动脉高压。用恩格列净治疗肥胖+sugen大鼠可改善代谢综合征，降低线粒体活性氧和miR-193b水平，恢复NFYA/sGC活性，并预防EIPH。结论：在射血分数保留的心力衰竭和CpcPH模型中，代谢综合征有助于通过增强活性氧和 miR-193b 表达来抑制肺血管功能障碍和 EIPH，从而下调 NFYA 依赖性 sGCβ1 表达。腺相关病毒介导的 NFYA 过表达和 SGLT2 抑制可恢复 NFYA-sGCβ1-cGMP 信号传导并改善 EIPH。