title: A high-affinity, dimeric inhibitor of PSD-95 bivalently interacts with PDZ1-2 and protects against ischemic brain damage.
abstract: 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.
authors.affiliation: Department of Medicinal Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark. anba@farma.ku.dk
authors.forename: Anders
authors.initials: A
authors.lastname: Bach
authors.forename: Bettina H
authors.initials: BH
authors.lastname: Clausen
authors.forename: Magda
authors.initials: M
authors.lastname: Møller
authors.forename: Bente
authors.initials: B
authors.lastname: Vestergaard
authors.forename: Celestine N
authors.initials: CN
authors.lastname: Chi
authors.forename: Adam
authors.initials: A
authors.lastname: Round
authors.forename: Pernille L
authors.initials: PL
authors.lastname: Sørensen
authors.forename: Klaus B
authors.initials: KB
authors.lastname: Nissen
authors.forename: Jette S
authors.initials: JS
authors.lastname: Kastrup
authors.forename: Michael
authors.initials: M
authors.lastname: Gajhede
authors.forename: Per
authors.initials: P
authors.lastname: Jemth
authors.forename: Anders S
authors.initials: AS
authors.lastname: Kristensen
authors.forename: Patrik
authors.initials: P
authors.lastname: Lundström
authors.forename: Kate L
authors.initials: KL
authors.lastname: Lambertsen
authors.forename: Kristian
authors.initials: K
authors.lastname: Strømgaard
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001812:Blood-Brain Barrier; D018360:Crystallography, X-Ray; D000076122:Disks Large Homolog 4 Protein; D015195:Drug Design; D004353:Drug Evaluation, Preclinical; D051528:Guanylate Kinases / Q000037:antagonists & inhibitors; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000188:drug therapy* / Q000473:pathology; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors*; D007859:Learning Disabilities / Q000209:etiology / Q000517:prevention & control; D008297:Male; D008565:Membrane Proteins / Q000037:antagonists & inhibitors*; D051379:Mice; D008810:Mice, Inbred C57BL; D008958:Models, Molecular; D008969:Molecular Sequence Data; D058990:Molecular Targeted Therapy; D009069:Movement Disorders / Q000209:etiology / Q000517:prevention & control; D018696:Neuroprotective Agents / Q000138:chemical synthesis / Q000494:pharmacology / Q000627:therapeutic use*; D019906:Nuclear Magnetic Resonance, Biomolecular; D054731:PDZ Domains / Q000187:drug effects; D010455:Peptides / Q000138:chemical synthesis / Q000494:pharmacology / Q000627:therapeutic use*; D004856:Postural Balance; D011487:Protein Conformation; D012678:Sensation Disorders / Q000209:etiology / Q000517:prevention & control
chemical_list: C501444:DLG4 protein, human; D000076122:Disks Large Homolog 4 Protein; C501447:Dlg4 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D018696:Neuroprotective Agents; D010455:Peptides; C571729:Tat-NPEG4(IETDV)2; D051528:Guanylate Kinases