S-nitrosylation of Src by NR2B-nNOS signal causes Src activation and NR2B tyrosine phosphorylation in levodopa-induced dyskinetic rat model

Abstract

<jats:p> Abnormality in Src PSD-95 NR2B signaling complex assemble occurs in levodopa-induced dyskinesia (LID). N-methyl-D-aspartate receptor (NMDAR) subunit NR2B tyrosine phosphorylation mediated by Src family protein tyrosine kinases is closely associated with dyskinesia. Src autophosphorylation (p-Src) is an important part of Src-catalyzed phosphorylation of NR2B. In addition, the neuronal nitric oxide synthase (nNOS)-derived NO (nNOS/NO) signal which was also involved in dyskinesia recently was proved to participate in the regulation of Src function. Yet, the detailed signal mechanism about the interactions of NR2B, nNOS, and Src is still unknown. In the present study, we investigated the influences of nNOS on Src activation and NR2B tyrosine phosphorylation in dyskinetic rat model by immunoblotting and immunoprecipitation. The results demonstrated that chronic levodopa treatment resulted in downregulation of p-nNOS-S847, one marker of nNOS overactivation. Coinstantaneously, the S-nitrosylation (SNO-Src) and autophosphorylation (p-Src) of Src and NR2B tyrosine phosphorylation were upregulated in dyskinetic rat model. Conversely, administration of 7-NI, one nNOS inhibitor, reversed all these effects of levodopa treatment. Besides, NR2B-containing NMDAR (NR2B/NMDAR) antagonist CP-101,606 could upregulate p-nNOS-S847 and thus attenuate nNOS activation and simultaneously reduce the SNO-Src, p-Src, and NR2B tyrosine phosphorylation. Taken together, the S-nitrosylation of Src is caused by nNOS/NO signal, which is overactivated via Ca<jats:sup>2+</jats:sup> influx dependent on NR2B/NMDAR, and subsequently facilitates Src auto-tyrosine phosphorylation and further phosphorylates NR2B. The “NR2B/NMDAR–nNOS/NO–SNO-Src–p-Src–NR2B/NMDAR” signaling cycle may be the molecular basis of NR2B tyrosine phosphorylation upward positive feedback, which demonstrates the possibility as one latent target for dyskinesia therapy. </jats:p>

Role of N-Methyl-D-Aspartate Receptor NR2B Subunit in Inflammatory Arthritis-Induced Chronic Pain and Peripheral Sensitized Neuropathic Pain: A Systematic Review

“…Ca 2+ influx of the NR2B subunit is excessively activated, promoting tyrosine phosphorylation of Src, which further phosphorylates NR2B. 48 Since the NR2B structure is specific for switching ion channels, activation of the NR2B subunit results in changes in concentrations of intracellular and extracellular ions under actions of voltage-gated ion channels, 49 leading to pain occurrence. GPCRs stimulation induces NR2B subunit activation and promotes CNS plasticity.…”

Systemic Inflammation Increases the Susceptibility to Levodopa-Induced Dyskinesia in 6-OHDA Lesioned Rats by Targeting the NR2B-Medicated PKC/MEK/ERK Pathway

“…The phosphorylation of the NR2B subunit plays a very important role in the regulation of NMDA receptor function and has been connected to alterations of synaptic efficacy of the NMDA receptor. CP-101,606, an NR2B-selective antagonist, has been reported to reduce dyskinesia as measured by clinical scoring (Ba et al, 2019). A possible role for the NR2B receptor in dyskinesia in patients with PD (Herring et al, 2017) or Parkinsonian animals (Gan et al, 2014) has been highlighted.…”

Nitrosative stress in Parkinson’s disease

“…These axodendritic impairments alter network connectivity, which is associated with cognitive decline and even neuronal death. NO also regulates NMDAR-excitotoxicity 55 that can be further exacerbated by SNO-Src and SNO-SHP-2 56,57 . Src, a family of proteins tyrosine kinases, was found to be activated by autophosphorylation and S-nitrosylation leading to the phosphorylation of NMDAR subunit NR2B and the subsequent increase of NMDAR activity.…”