A high-affinity, dimeric inhibitor of PSD-95 bivalently interacts with PDZ1-2 and protects against ischemic brain damage

作者：Bach Anders^*; Clausen Bettina H; Moller Magda; Vestergaard Bente; Chi Celestine N; Round Adam; Sorensen Pernille L; Nissen Klaus B; Kastrup Jette S; Gajhede Michael; Jemth Per; Kristensen Anders S; Lundstrom Patrik; Lambertsen Kate L; Stromgaard Kristian

来源：Proceedings of the National Academy of Sciences, 2012, 109(9): 3317-3322.

DOI：10.1073/pnas.1113761109

• drug discovery
• ischemic stroke
• protein-protein interactions

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.

• 出版日期2012-2-28