Background:Aldosterone is a critical pathological driver for cardiac and renal diseases. We recently discovered that mutant atrial natriuretic peptide (MANP), a novel atrial natriuretic peptide (ANP) analog, possessed more potent aldosterone inhibitory action than ANP in vivo. MANP and natriuretic peptide (NP)-augmenting therapy sacubitril/valsartan are under investigations for human hypertension treatment. Understanding the elusive mechanism of aldosterone inhibition by NPs remains to be a priority. Conflicting results were reported on the roles of the pGC-A (particulate guanylyl cyclase A receptor) and NP clearance receptor in aldosterone inhibition. Furthermore, the function of PKG (protein kinase G) and PDEs (phosphodiesterases) on aldosterone regulation are not clear.Methods:In the present study, we investigated the molecular mechanism of aldosterone regulation in a human adrenocortical cell line H295R and in mice.Results:We first provided evidence to show that pGC-A, not NP clearance receptor, mediates aldosterone inhibition. Next, we confirmed that MANP inhibits aldosterone via PDE2 (phosphodiesterase 2) not PKG, with specific agonists, antagonists, siRNA silencing, and fluorescence resonance energy transfer experiments. Further, the inhibitory effect is mediated by a reduction of intracellular Ca2+ levels. We then illustrated that MANP directly reduces aldosterone synthase CYP11B2 (cytochrome p450 family 11 subfamily b member 2) expression via PDE2. Last, in PDE2 knockout mice, consistent with in vitro findings, embryonic adrenal CYP11B2 is markedly increased.Conclusions:Our results innovatively explore and expand the NP/pGC-A/3',5', cyclic guanosine monophosphate (cGMP)/PDE2 pathway for aldosterone inhibition by MANP in vitro and in vivo. In addition, our data also support the development of MANP as a novel ANP analog drug for aldosterone excess treatment.

中文翻译：

---

在 H295R 细胞和小鼠中，MANP 激活 cGMP 通过 PDE2 和 CYP11B2 抑制醛固酮

背景：醛固酮是心脏和肾脏疾病的关键病理驱动因素。我们最近发现突变心房钠尿肽（MANP）是一种新型心房钠尿肽（ANP）类似物，在体内具有比ANP更有效的醛固酮抑制作用。MANP 和利钠肽 (NP) 增强疗法 sacubitril/valsartan 正在研究用于人类高血压的治疗。了解纳米粒子抑制醛固酮的难以捉摸的机制仍然是一个优先事项。关于 pGC-A（颗粒鸟苷酸环化酶 A 受体）和 NP 清除受体在醛固酮抑制中的作用，报道了相互矛盾的结果。此外，PKG（蛋白激酶G）和PDE（磷酸二酯酶）对醛固酮调节的功能尚不清楚。方法：在本研究中，我们研究了人肾上腺皮质细胞系H295R和小鼠中醛固酮调节的分子机制。结果：我们首先提供证据表明 pGC-A（而不是 NP 清除受体）介导醛固酮抑制。接下来，我们通过特异性激动剂、拮抗剂、siRNA沉默和荧光共振能量转移实验，证实MANP通过PDE2（磷酸二酯酶2）而不是PKG抑制醛固酮。此外，抑制作用是通过降低细胞内Ca2+水平来介导的。然后我们证明，MANP 通过 PDE2 直接降低醛固酮合酶 CYP11B2（细胞色素 p450 家族 11 亚家族 b 成员 2）的表达。最后，在PDE2敲除小鼠中，与体外研究结果一致，胚胎肾上腺CYP11B2显着增加。结论：我们的结果创新性地探索和扩展了NP/pGC-A/3',5'、环磷酸鸟苷(cGMP)/PDE2通路用于 MANP 体外和体内醛固酮抑制。此外，我们的数据还支持将MANP开发为一种用于醛固酮过量治疗的新型ANP类似药物。