Cardiorenal Research Laboratory, Department of Cardiovascular Medicine (Y.C., S.R.I., X.M., J.C.B.), Mayo Clinic, Rochester MN.
The Institute for Diabetes' Obesity' and Metabolism, University of Pennsylvania, Philadelphia (Y.C.).
Hypertension. 2022 Aug;79(8):1702-1712. doi: 10.1161/HYPERTENSIONAHA.121.18906. Epub 2022 Jun 8.
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.
In the present study, we investigated the molecular mechanism of aldosterone regulation in a human adrenocortical cell line H295R and in mice.
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.
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.
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，新型心钠肽（ANP）类似物突变心房利钠肽（MANP）在体内比 ANP 具有更强的醛固酮抑制作用。MANP 和利钠肽（NP）增强治疗沙库巴曲缬沙坦正在被研究用于治疗人类高血压。了解 NP 抑制醛固酮的难以捉摸的机制仍然是当务之急。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，报告结果相互矛盾。此外，PKG（蛋白激酶 G）和 PDEs（磷酸二酯酶）在醛固酮调节中的作用尚不清楚。
本研究采用人类肾上腺皮质细胞系 H295R 和小鼠，研究醛固酮调节的分子机制。
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，且该抑制作用是通过降低细胞内 Ca2+水平介导的。然后，我们说明 MANP 通过 PDE2 直接降低 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，与体外发现一致，胚胎肾上腺 CYP11B2 明显增加。
我们的研究结果创新性地探索和扩展了 NP/pGC-A/3'，5'，环鸟苷酸（cGMP）/PDE2 通路，用于 MANP 体外和体内抑制醛固酮。此外，我们的数据还支持将 MANP 开发为一种新型 ANP 类似物药物，用于治疗醛固酮过多。
