Data_Sheet_6_A Novel PDE4D Inhibitor BPN14770 Reverses Scopolamine-Induced Cognitive Deficits via cAMP/SIRT1/Akt/Bcl-2 Pathway.xlsx

A global, quantitative proteomics/systems-biology analysis of the selective pharmacological inhibition of phosphodiesterase-4D (PDE4D) revealed the differential regulation of pathways associated with neuroplasticity in memory-associated brain regions. Subtype selective inhibitors of PDE4D bind in an allosteric site that differs between mice and humans in a single amino acid (tyrosine vs. phenylalanine, respectively). Therefore to study selective inhibition of PDE4D by BPN14770, a subtype selective allosteric inhibitor of PDE4D, we utilized a line of mice in which the PDE4D gene had been humanized by mutating the critical tyrosine to phenylalanine. Relatively low doses of BPN14770 were effective at reversing scopolamine-induced memory and cognitive deficits in humanized PDE4D mice. Inhibition of PDE4D alters the expression of protein kinase A (PKA), Sirt1, Akt, and Bcl-2/Bax which are components of signaling pathways for regulating endocrine response, stress resistance, neuronal autophagy, and apoptosis. Treatment with a series of antagonists, such as H89, sirtinol, and MK-2206, reversed the effect of BPN14770 as shown by behavioral tests and immunoblot analysis. These findings suggest that inhibition of PDE4D enhances signaling through the cAMP-PKA-SIRT1-Akt -Bcl-2/Bax pathway and thereby may provide therapeutic benefit in neurocognitive disorders.

针对磷酸二酯酶4D（phosphodiesterase-4D, PDE4D）的选择性药理学抑制所开展的全球性定量蛋白质组学/系统生物学分析，揭示了记忆相关脑区内与神经可塑性相关通路的差异性调控模式。PDE4D亚型选择性抑制剂结合于别构位点，该位点在小鼠与人类之间仅存在单个氨基酸差异（分别为酪氨酸与苯丙氨酸）。因此，为研究BPN14770——一种PDE4D亚型选择性别构抑制剂——对PDE4D的选择性抑制作用，我们构建了一株PDE4D基因人源化小鼠品系，通过将关键酪氨酸残基突变为苯丙氨酸实现基因人源化。在该PDE4D人源化小鼠模型中，较低剂量的BPN14770即可有效逆转东莨菪碱诱导的记忆与认知功能缺损。PDE4D抑制可改变蛋白激酶A（protein kinase A, PKA）、沉默信息调节因子1（Sirt1）、Akt以及Bcl-2/Bax的表达水平，上述分子均为调控内分泌应答、应激抵抗、神经元自噬与细胞凋亡的信号通路组成成分。通过H89、西特林（sirtinol）、MK-2206等一系列拮抗剂处理，可逆转BPN14770的上述效应，该结果经行为学实验与免疫印迹分析得以验证。上述研究结果表明，PDE4D抑制可增强cAMP-PKA-SIRT1-Akt-Bcl-2/Bax信号通路的信号转导，因此或可为神经认知障碍的治疗提供临床益处。