A high-affinity, dimeric inhibitor of PSD-95 bivalently interacts with PDZ1-2 and protects against ischemic brain damage
A high-affinity, dimeric inhibitor of PSD-95 bivalently interacts with PDZ1-2 and protects against ischemic brain damage
复制标题
DOI：
10.1073/pnas.1113761109
复制
发表时间：
2012-02-28
影响因子：
11.1
通讯作者：
Stromgaard, Kristian
中科院分区：
文献类型：
--
作者：
Bach, Anders;Clausen, Bettina H.;Stromgaard, Kristian
抑制突触支架蛋白突触后密度蛋白-95（PSD-95）、神经元型一氧化氮合酶（nNOS）和N-甲基-D-天冬氨酸（NMDA）受体的三元蛋白复合物是治疗缺血性脑损伤的潜在策略，但缺乏高亲和力抑制剂。在这里，我们报告了一种新型二聚体抑制剂Tat-NPEG 4（IETDV）（2）（Tat-N-二聚体）的设计和合成，它以前所未有的4.6 nM高亲和力结合PSD-95的串联PDZ 1 -2结构域，并显示出广泛的蛋白酶抗性。通过人血浆中的稳定性测量进行体外评估。X射线晶体学、核磁共振和小角X射线散射（SAXS）分析表明，PDZ 1 -2与二聚体抑制剂之间存在真正的二价相互作用，并为二聚体抑制剂诱导PDZ 1 -2构象变化提供了动力学模型。单次静脉注射Tat-N-二聚体（3 nmol/g）的小鼠局灶性脑缺血减少梗死体积40%，恢复运动功能。因此，Tat-N-二聚体是一种高度有效的神经保护剂，具有治疗中风的潜力。
Inhibition of the ternary protein complex of the synaptic scaffolding protein postsynaptic density protein-95 (PSD-95), neuronal nitric oxide synthase (nNOS), and the N-methyl-D-aspartate (NMDA) receptor is a potential strategy for treating ischemic brain damage, but high-affinity inhibitors are lacking. Here we report the design and synthesis of a novel dimeric inhibitor, Tat-NPEG4(IETDV)(2) (Tat-N-dimer), which binds the tandem PDZ1-2 domain of PSD-95 with an unprecedented high affinity of 4.6 nM, and displays extensive protease-resistance as evaluated in vitro by stability-measurements in human blood plasma. X-ray crystallography, NMR, and small-angle X-ray scattering (SAXS) deduced a true bivalent interaction between dimeric inhibitor and PDZ1-2, and also provided a dynamic model of the conformational changes of PDZ1-2 induced by the dimeric inhibitor. A single intravenous injection of Tat-N-dimer (3 nmol/g) to mice subjected to focal cerebral ischemia reduces infarct volume with 40% and restores motor functions. Thus, Tat-N-dimer is a highly efficacious neuroprotective agent with therapeutic potential in stroke.