Disruption of nNOS-PSD95 protein-protein interaction inhibits acute thermal hyperalgesia and chronic mechanical allodynia in rodents.
OBJECTIVE
Post-synaptic density protein 95 (PSD95) contains three PSD95/Dosophilia disc large/ZO-1 homology domains and links neuronal nitric oxide synthase (nNOS) with the N-methyl-D-aspartic acid (NMDA) receptor. This report assesses the effects of disruption of the protein-protein interaction between nNOS and PSD95 on pain sensitivity in rodent models of hyperalgesia and neuropathic pain.


METHODS
We generated two molecules that interfered with the nNOS-PSD95 interaction: IC87201, a small molecule inhibitor; and tat-nNOS (residues 1-299), a cell permeable fusion protein containing the PSD95 binding domain of nNOS. We then characterized these inhibitors using in vitro and in vivo models of acute hyperalgesia and chronic allodynia, both of which are thought to require nNOS activation.


RESULTS
IC87201 and tat-nNOS (1-299) inhibited the in vitro binding of nNOS with PSD95, without inhibiting nNOS catalytic activity. Both inhibitors also blocked NMDA-induced 3',5'-cyclic guanosine monophosphate (cGMP) production in primary hippocampal cultures. Intrathecal administration of either inhibitor potently reversed NMDA-induced thermal hyperalgesia in mice. At anti-hyperalgesic doses, there was no effect on acute pain thresholds or motor coordination. Intrathecal administration of IC87201 and tat-nNOS also reversed mechanical allodynia induced by chronic constriction of the sciatic nerve.


CONCLUSIONS
nNOS-PSD95 interaction is important in maintaining hypersensitivity in acute and chronic pain. Disruption of the nNOS-PSD95 interaction provides a novel approach to obtain selective anti-hyperalgesic compounds.
Florio
S K
SK
ICOS Corporation, Bothell, WA, USA.
Loh
C
C
Huang
S M
SM
Iwamaye
A E
AE
Kitto
K F
KF
Fowler
K W
KW
Treiberg
J A
JA
Hayflick
J S
JS
Walker
J M
JM
Fairbanks
C A
CA
Lai
Y
Y
D000818:Animals; D002733:Chlorophenols / Q000008:administration & dosage / Q000494:pharmacology; D006152:Cyclic GMP / Q000378:metabolism; D004195:Disease Models, Animal; D000076122:Disks Large Homolog 4 Protein; D051528:Guanylate Kinases; D006930:Hyperalgesia / Q000503:physiopathology; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D009437:Neuralgia / Q000503:physiopathology; D052248:Nitric Oxide Synthase Type I / Q000008:administration & dosage / Q000378:metabolism*; D017288:Pain Threshold; D011485:Protein Binding; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D014230:Triazoles / Q000008:administration & dosage / Q000494:pharmacology; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000008:administration & dosage
C546030:2-((1H-benzo(d)(1,2,3)triazol-5-ylamino)methyl)-4,6-dichlorophenol; D002733:Chlorophenols; D000076122:Disks Large Homolog 4 Protein; C501447:Dlg4 protein, mouse; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D016194:Receptors, N-Methyl-D-Aspartate; D014230:Triazoles; D054322:tat Gene Products, Human Immunodeficiency Virus; D052248:Nitric Oxide Synthase Type I; D051528:Guanylate Kinases; D006152:Cyclic GMP