Background:Disruption of cyclic nucleotide signaling in sympathetic postganglionic neurons contributes to impaired intracellular calcium handling (Ca²⁺) and the development of dysautonomia during the early stages of hypertension, although how this occurs is poorly understood. Emerging evidence supports the uncoupling of signalosomes in distinct cellular compartments involving cyclic nucleotide–sensitive PDEs (phosphodiesterases), which may underpin the autonomic phenotype in stellate neurons.Methods:Using a combination of single-cell RNA sequencing together with Forster resonance energy transfer–based sensors to monitor cyclic adenosine 3’,5’-monophosphate, PKA (protein kinase A)-dependent phosphorylation and cGMP (cyclic guanosine 3’,5’-monophosphate), we tested the hypothesis that dysregulation occurs in a sub-family of PDEs in the cytosol and outer mitochondrial membrane of neurons from the stellate ganglion.Results:PDE2A, 6D, 7A, 9A genes were highly expressed in young Wistar neurons and also conserved in neurons from spontaneously hypertensive rats (SHRs). In stellate neurons from prehypertensive SHRs, we found the levels of cyclic adenosine 3’,5’-monophosphate and cGMP at the outer mitochondrial membrane were decreased compared with normal neurons. The reduced cyclic adenosine 3’,5’-monophosphate response was due to the hydrolytic activity of overexpressed PDE2A2 located at the mitochondria. Normal cyclic adenosine 3’,5’-monophosphate levels were re-established by inhibition of PDE2A. There was also a greater PKA-dependent phosphorylation in the cytosol and at the outer mitochondrial membrane in spontaneously hypertensive rat neurons, where this response was regulated by protein phosphatases. The cGMP response was only restored by inhibition of PDE6.Conclusions:When taken together, these results suggest that site-specific inhibition of PDE2A and PDE6D at the outer mitochondrial membrane may provide a therapeutic target to ameliorate cardiac sympathetic impairment during the onset of hypertension.

中文翻译：

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高血压早期交感神经元线粒体外膜的异常环状核苷酸信号传导

背景：交感神经节后神经元中环核苷酸信号的中断导致细胞内钙处理（Ca ²⁺) 以及高血压早期阶段自主神经功能障碍的发展，尽管人们对这种情况的发生机制知之甚少。新出现的证据支持信号体在涉及环核苷酸敏感性 PDE（磷酸二酯酶）的不同细胞区室中解偶联，这可能支持星状神经元中的自主表型。方法：使用单细胞 RNA 测序与基于 Forster 共振能量转移的组合传感器监测环腺苷 3',5'-单磷酸、PKA（蛋白激酶 A）依赖性磷酸化和 cGMP（环鸟苷 3',5'-单磷酸），我们检验了失调发生在 PDE 亚家族中的假设在来自星状神经节的神经元的胞质溶胶和线粒体外膜中。结果：PDE2A、6D、7A、9A 基因在年轻的 Wistar 神经元中高度表达，并且在自发性高血压大鼠 (SHR) 的神经元中也很保守。在高血压前期 SHR 的星状神经元中，我们发现与正常神经元相比，线粒体外膜的环腺苷 3',5'-一磷酸和 cGMP 水平降低。减少的环状腺苷 3',5'-一磷酸反应是由于位于线粒体的过表达 PDE2A2 的水解活性。通过抑制 PDE2A 重新建立正常的环腺苷 3',5'-一磷酸水平。在自发性高血压大鼠神经元的胞质溶胶和线粒体外膜中也存在更大的 PKA 依赖性磷酸化，这种反应受蛋白磷酸酶的调节。只有通过抑制 PDE6 才能恢复 cGMP 反应。结论：