Exploring the EphB2-NMDA receptor interaction in spinal cord injury-induced neuropathic pain

探索 EphB2-NMDA 受体在脊髓损伤引起的神经性疼痛中的相互作用

• 批准号: 10245041
• 负责人: MANUEL L COVARRUBIAS
• 金额: $ 50.94万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10245041
• 关键词: 3-Dimensional; Affect; Amino Acids; Anatomy; Animal Model; Behavior; Calcium; Cells; Cervical; Cervical spinal cord injury; Chemosensitization; Chronic; Complex; Contusions; Development; EphB2 Receptor; Ephrin B Receptor; Event; Excitatory Synapse; Extracellular Domain; Future; Heterogeneity; In Vitro; Individual; Intervention; Link; Mediating; Modeling; Molecular; Mus; N-Methyl-D-Aspartate Receptors; Neurons; Nociception; Opioid; Pain; Pathologic; Persistent pain; Pharmacology; Phenotype; Phosphorylation; Population; Posterior Horn Cells; Preparation; Refractory; Rodent Model; Sensory; Signal Transduction; Spinal Cord; Spinal Cord Contusions; Spinal cord injury; Surface; Synapses; Synaptic Receptors; Synaptic Transmission; Synaptic plasticity; Tactile; Testing; Thermal Hyperalgesias; Viral Vector; Work; allodynia; base; central sensitization; chronic pain; dorsal horn; effective therapy; extracellular; in vivo; innovation; knock-down; mutant; neurotransmission; novel; painful neuropathy; patch clamp; prevent; psychologic; receptor; receptor function; side effect; small hairpin RNA; synaptic function; targeted agent; targeted treatment; therapeutic target; transmission process; vector

Project Summary / Abstract: In a rodent model of cervical spinal cord injury (SCI), we propose to examine the contribution of altered EphB2 receptor-NMDA receptor (NMDAR) interaction to both excitatory synaptic neurotransmission in the superficial dorsal horn (DH) and persistent neuropathic pain (NP). The development of NP occurs in a significant portion of individuals affected by SCI, resulting in debilitating and often chronic physical and psychological burdens. Importantly, this pathological pain is particularly refractory to treatment, urgently calling for the identification of mechanistic targets that both robustly regulate pathological pain and avoid the devastating effects of opioid- based interventions. Hyperexcitability of DH circuitry (“central sensitization”) is a major substrate for NP after SCI. Studies have shown that NP is linked to EphB/ephrinB signaling through potentiation of NMDAR function, suggesting that the EphB-NMDAR interaction may be an important target for control of SCI-induced NP. We recently discovered that the EphB2-NMDAR interaction is regulated by a single extracellular amino acid of EphB2 (Y504). We demonstrated in vitro that EphB2-Y504 phosphorylation is required in spinal cord neurons for EphB-NMDAR interaction, NMDAR synaptic localization, and excitatory synapse function. We also found that transduction of DH neurons in vivo with EphB2 that constitutively interacts with the NMDAR results in long- lasting allodynia. We hypothesize that modulating the EphB2-NMDAR interaction in superficial dorsal horn (DH) neurons will impact synaptic localization and function of NMDARs, excitatory synaptic transmission between primary sensory afferents and DH neurons, and NP-related behaviors after cervical contusion SCI. Aim 1. Determine whether interaction with EphB2 drives NMDA receptors to synapses between primary nociceptive afferents and superficial DH neurons following cervical SCI. We will determine whether knocking down EphB2 in both uninjured and cervical contusion SCI mice using DH neuron subtype- specific expression of EphB2-shRNA reduces the localization of NMDAR subunits to excitatory synapses. Aim 2. Determine whether EphB2 regulates excitatory synaptic transmission in DH and NP-related behaviors after cervical SCI. We will determine whether DH neuron subtype-specific knockdown of EphB2 impacts: (2a) synaptic transmission between primary afferents and laminae I-II neurons using whole-cell patch clamp recording in an intact ex vivo preparation; and (2b) initiation and/or persistence of NP-related behaviors. Aim 3. Determine whether EphB2-Y504 phosphorylation regulates EphB2-NMDAR synaptic interaction in the DH and NP-related behaviors after cervical SCI. By expressing wild-type EphB2-Y504 or constitutively-phosphorylated (Y504E) or non-phosphorylatable (Y504F) mutants in a DH neuron subtype- specific manner, we will determine whether modulating EphB2-Y504 phosphorylation impacts: (3a) EphB2- NMDAR interaction, (3a) NMDAR levels at excitatory synapses, (3c) excitatory synaptic transmission between primary sensory afferents and DH neurons, and (3d) NP-related behaviors after cervical contusion SCI.

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