Department of Pharmacology (S.Y., M.K., H.L., H.K., G.H.E.), Chonnam National University Medical School, Hwasun, Korea.
Division of Clinical Pharmacology, Chonnam National University Hospital, Gwangju, Korea (G.K.).
Circulation. 2021 May 11;143(19):1912-1925. doi: 10.1161/CIRCULATIONAHA.119.043578. Epub 2021 Mar 10.
Although the clinical importance of heart failure with preserved ejection fraction has been extensively explored, most therapeutic regimens, including nitric oxide (NO) donors, lack therapeutic benefit. Although the clinical characteristics of heart failure with preserved ejection fraction are somewhat heterogeneous, diastolic dysfunction (DD) is one of the most important features. Here we report that neuronal NO synthase (nNOS) induces DD by S-nitrosylation of HDAC2 (histone deacetylase 2).
Two animal models of DD-SAUNA (SAlty drinking water/Unilateral Nephrectomy/Aldosterone) and mild transverse aortic constriction mice-as well as human heart samples from patients with left ventricular hypertrophy were used. Genetically modified mice that were either nNOS-ablated or HDAC2 S-nitrosylation-resistant were also challenged. N(ω)-propyl-L-arginine, an nNOS selective inhibitor, and dimethyl fumarate, an NRF2 (nuclear factor erythroid 2-related factor 2) inducer, were used. Molecular events were further checked in human left ventricle specimens.
SAUNA or mild transverse aortic constriction stress impaired diastolic function and exercise tolerance without overt systolic failure. Among the posttranslational modifications tested, S-nitrosylation was most dramatically increased in both models. Utilizing heart samples from both mice and humans, we observed increases in nNOS expression and NO production. N(ω)-propyl-L-arginine alleviated the development of DD in vivo. Similarly, nNOS knockout mice were resistant to SAUNA stress. nNOS-induced S-nitrosylation of HDAC2 was relayed by transnitrosylation of GAPDH. HDAC2 S-nitrosylation was confirmed in both DD mouse and human left ventricular hypertrophy. S-nitrosylation of HDAC2 took place at C262 and C274. When DD was induced, HDAC2 S-nitrosylation was detected in wild-type mouse, but not in HDAC2 knock-in mouse heart that expressed HDAC2 C262A/C274A. In addition, HDAC2 C262A/C274A mice maintained normal diastolic function under DD stimuli. Gene delivery with adenovirus-associated virus 9 (AAV9)-NRF2, a putative denitrosylase of HDAC2, or pharmacological intervention by dimethyl fumarate successfully induced HDAC2 denitrosylation and mitigated DD in vivo.
Our observations are the first to demonstrate a new mechanism underlying DD pathophysiology. Our results provide theoretical and experimental evidence to explain the ineffectiveness of conventional NO enhancement trials for improving DD with heart failure symptoms. More important, our results suggest that reduction of NO or denitrosylation of HDAC2 may provide a new therapeutic platform for the treatment of refractory heart failure with preserved ejection fraction.
尽管心力衰竭伴射血分数保留的临床重要性已被广泛研究，但大多数治疗方案，包括一氧化氮（NO）供体，缺乏治疗益处。尽管心力衰竭伴射血分数保留的临床特征有些不同，但舒张功能障碍（DD）是最重要的特征之一。在这里，我们报告神经元型一氧化氮合酶（nNOS）通过 S-亚硝基化 HDAC2（组蛋白去乙酰化酶 2）诱导 DD。
使用两种 DD-SAUNA（盐饮水/单侧肾切除术/醛固酮）和轻度主动脉缩窄的动物模型以及来自左心室肥厚患者的人类心脏样本。还对 nNOS 缺失或 HDAC2 S-亚硝基化抗性的基因修饰小鼠进行了挑战。使用 nNOS 选择性抑制剂 N（ω）-丙基-L-精氨酸和 NRF2（核因子红细胞 2 相关因子 2）诱导剂二甲基富马酸。进一步在人类左心室标本中检查分子事件。
SAUNA 或轻度主动脉缩窄应激导致舒张功能障碍和运动耐量下降，而无明显收缩功能衰竭。在所测试的翻译后修饰中，S-亚硝基化增加最为明显。利用来自小鼠和人类的心脏样本，我们观察到 nNOS 表达和 NO 产生增加。N（ω）-丙基-L-精氨酸可减轻体内 DD 的发生。同样，nNOS 缺失小鼠对 SAUNA 应激具有抗性。nNOS 诱导的 HDAC2 S-亚硝基化通过 GAPDH 的转亚硝基化传递。在 DD 小鼠和人类左心室肥厚中均证实了 HDAC2 的 S-亚硝基化。HDAC2 S-亚硝基化发生在 C262 和 C274 处。当诱导 DD 时，在野生型小鼠中检测到 HDAC2 S-亚硝基化，但在表达 HDAC2 C262A/C274A 的 HDAC2 敲入小鼠心脏中未检测到。此外，在 DD 刺激下，HDAC2 C262A/C274A 小鼠保持正常的舒张功能。用腺相关病毒 9（AAV9）-NRF2 进行基因传递，NRF2 是 HDAC2 的一种潜在脱亚硝基酶，或用二甲基富马酸进行药理学干预，可成功诱导体内 HDAC2 脱亚硝基化并减轻 DD。
我们的观察结果首次证明了 DD 病理生理学的新机制。我们的研究结果为解释具有心力衰竭症状的常规 NO 增强试验改善 DD 无效的原因提供了理论和实验依据。更重要的是，我们的结果表明，减少 NO 或 HDAC2 的脱亚硝基化可能为治疗难治性心力衰竭伴射血分数保留提供新的治疗平台。
