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

> **NIH NIH R01** · THOMAS JEFFERSON UNIVERSITY · 2021 · $509,441

## Abstract

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, (...

## Key facts

- **NIH application ID:** 10245041
- **Project number:** 5R01NS110385-04
- **Recipient organization:** THOMAS JEFFERSON UNIVERSITY
- **Principal Investigator:** MANUEL L COVARRUBIAS
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $509,441
- **Award type:** 5
- **Project period:** 2018-09-01 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10245041

## Citation

> US National Institutes of Health, RePORTER application 10245041, Exploring the EphB2-NMDA receptor interaction in spinal cord injury-induced neuropathic pain (5R01NS110385-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10245041. Licensed CC0.

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