Intrathecal injection of the peptide myr-NR2B9c attenuates bone cancer pain via perturbing N-methyl-D-aspartate receptor-PSD-95 protein interactions in mice.
BACKGROUND
N-methyl-D-aspartate receptor (NMDARs)-dependent central sensitization plays an important role in cancer pain. Binding of NMDAR subunit 2B (NR2B) by postsynaptic density protein-95 (PSD-95) can couple NMDAR activity to intracellular enzymes, such as neuronal nitric oxide synthase (nNOS), facilitate downstream signaling pathways, and modulate NMDAR stability, contributing to synaptic plasticity. In this study, we investigated whether perturbing the specific interaction between spinal NR2B-containing NMDAR and PSD-95, using a peptide-mimetic strategy, could attenuate bone cancer-related pain behaviors.


METHODS
Osteosarcoma cells were implanted into the intramedullary space of the right femurs of C3H/HeJ mice to induce progressive bone cancer-related pain behaviors. Western blotting was applied to examine the expression of spinal phospho-Tyr1472 NR2B, nNOS, and PSD-95. We further investigated the effects of intrathecal injection of the mimetic peptide Myr-NR2B9c, which competitively disrupts the interaction between PSD-95 and NR2B, on nociceptive behaviors and on the upregulation of phospho-Tyr1472 NR2B, nNOS, and PSD-95 associated with bone cancer pain in the spinal cord.


RESULTS
Inoculation of osteosarcoma cells induced progressive bone cancer pain and resulted in a significant upregulation of phospho-Tyr1472 NR2B, nNOS, and PSD-95. Intrathecal administration of Myr-NR2B9c attenuated bone cancer-evoked mechanical allodynia, thermal hyperalgesia, and reduced spinal phospho-Tyr1472 NR2B, nNOS, and PSD-95 expression.


CONCLUSIONS
Intrathecal administration of Myr-NR2B9c reduced bone cancer pain. Internalization of spinal NR2B and dissociation NR2B-containing NMDARs activation from downstream nNOS signaling may contribute to the analgesic effects of Myr-NR2B9c. This approach may circumvent the negative consequences associated with blocking NMDARs, and may be a novel strategy for the treatment of bone cancer pain.
From the Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, China.
Yue
Y
Liu
Xinlong
X
Cui
Yu-E
YE
Sun
Xuli
X
Yang
Kun
K
Ni
Yu
Y
Zhou
Zhengliang
Z
Ma
Xiaoping
X
Gu
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D015153:Blotting, Western; D001859:Bone Neoplasms / Q000150:complications*; D000076122:Disks Large Homolog 4 Protein; D051528:Guanylate Kinases / Q000096:biosynthesis / Q000187:drug effects*; D006930:Hyperalgesia / Q000517:prevention & control; D047468:Immunoprecipitation; D007278:Injections, Spinal; D055666:Lipopeptides / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis / Q000187:drug effects*; D051379:Mice; D008809:Mice, Inbred C3H; D009368:Neoplasm Transplantation; D052248:Nitric Oxide Synthase Type I / Q000096:biosynthesis; D010146:Pain / Q000188:drug therapy* / Q000209:etiology / Q000523:psychology; D010766:Phosphorylation; D011485:Protein Binding / Q000187:drug effects; D016194:Receptors, N-Methyl-D-Aspartate / Q000096:biosynthesis / Q000187:drug effects*; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism; D014407:Tumor Cells, Cultured
D000076122:Disks Large Homolog 4 Protein; C501447:Dlg4 protein, mouse; D055666:Lipopeptides; D008565:Membrane Proteins; C121001:NR2B NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate; C000589394:myristoyl-lysyl-leucyl-seryl-seryl-isoleucyl-glutamyl-seryl-aspartyl-valine; D052248:Nitric Oxide Synthase Type I; D051528:Guanylate Kinases