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Nociceptor-expressed ephrin-B2 regulates inflammatory and neuropathic pain.

Zhao J, Yuan G, Cendan CM, Nassar MA, Lagerström MC, Kullander K, Gavazzi I, Wood JN - Mol Pain (2010)

Bottom Line: Formalin-induced pain behavior was attenuated in the second phase, and this correlated with diminished tyrosine phosphorylation of N-methyl-D-aspartic acid (NMDA) receptor subunit NR2B in the dorsal horn.Thermal hyperalgesia and mechanical allodynia were significantly reduced in the Seltzer model of neuropathic pain.Presynaptic ephrin-B2 expression thus plays an important role in regulating inflammatory pain through the regulation of synaptic plasticity in the dorsal horn and is also involved in the pathogenesis of some types of neuropathic pain.

View Article: PubMed Central - HTML - PubMed

Affiliation: Molecular Nociception Group, Wolfson Institute for Biomedical Research, Cruciform Building, University College London, London WC1E 6BT, UK.

ABSTRACT

Background: EphB receptors and their ephrin-B ligands play an important role in nervous system development, as well as synapse formation and plasticity in the adult brain. Recent studies show that intrathecal treatment with EphB-receptor activator ephrinB2-Fc induced thermal hyperalgesia and mechanical allodynia in rat, indicating that ephrin-B2 in small dorsal root ganglia (DRG) neurons and EphB receptors in the spinal cord modulate pain processing. To examine the role of ephrin-B2 in peripheral pain pathways, we deleted ephrin-B2 in Nav1.8+ nociceptive sensory neurons with the Cre-loxP system. Sensory neuron numbers and terminals were examined using neuronal makers. Pain behavior in acute, inflammatory and neuropathic pain models was assessed in the ephrin-B2 conditional knockout (CKO) mice. We also investigated the c-Fos expression and NMDA receptor NR2B phosphorylation in ephrin-B2 CKO mice and littermate controls.

Results: The ephrin-B2 CKO mice were healthy with no sensory neuron loss. However, pain-related behavior was substantially altered. Although acute pain behavior and motor co-ordination were normal, inflammatory pain was attenuated in ephrin-B2 mutant mice. Complete Freund's adjuvant (CFA)-induced mechanical hyperalgesia was halved. Formalin-induced pain behavior was attenuated in the second phase, and this correlated with diminished tyrosine phosphorylation of N-methyl-D-aspartic acid (NMDA) receptor subunit NR2B in the dorsal horn. Thermal hyperalgesia and mechanical allodynia were significantly reduced in the Seltzer model of neuropathic pain.

Conclusions: Presynaptic ephrin-B2 expression thus plays an important role in regulating inflammatory pain through the regulation of synaptic plasticity in the dorsal horn and is also involved in the pathogenesis of some types of neuropathic pain.

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Exon 2 of ephrin-B2 was deleted in DRG in Efnb2 CKO mice. (A) Diagram showing the ephrin-B2 wild-type locus, the targeted locus before and after Cre excision, Nav1.8 wild-type and Nav1.8-Cre locus. Exons are represented as numbered boxes. The loxP site (blank triangles) and the PCR primers (black arrows) are indicated. (B) Genotyping analysis with PCR. The DRGs genomic DNA from Efnb2 CKO mice, Efnb2fl/fl controls, heterozygous floxed exon 2 ephrin-B2 (Efnb2fl/+) mice and C57BL/6 wild-type (WT) mice were examined with PCR. The wild-type band (wt), floxed band (floxed) and Cre band (cre) were amplified with primer sets a/b, a/c and d/e respectively. The knockout band (ko) was found only from Efnb2 CKO mutant mice.
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Figure 1: Exon 2 of ephrin-B2 was deleted in DRG in Efnb2 CKO mice. (A) Diagram showing the ephrin-B2 wild-type locus, the targeted locus before and after Cre excision, Nav1.8 wild-type and Nav1.8-Cre locus. Exons are represented as numbered boxes. The loxP site (blank triangles) and the PCR primers (black arrows) are indicated. (B) Genotyping analysis with PCR. The DRGs genomic DNA from Efnb2 CKO mice, Efnb2fl/fl controls, heterozygous floxed exon 2 ephrin-B2 (Efnb2fl/+) mice and C57BL/6 wild-type (WT) mice were examined with PCR. The wild-type band (wt), floxed band (floxed) and Cre band (cre) were amplified with primer sets a/b, a/c and d/e respectively. The knockout band (ko) was found only from Efnb2 CKO mutant mice.

Mentions: We therefore tested a floxed exon 2 ephrin-B2 mouse [17], and crossed the mouse with Nav1.8-Cre. Figure 1A shows the ephrin-B2 locus, loxP sites and position of PCR primers. Using PCR analysis, we examined the Cre excision in CKO mice. The result shows that knockout band (400 bp) was clearly apparent from DRG DNA in the CKO mice (Figure 1B). We therefore used the exon 2 ephrin-B2 conditional knockout (Efnb2 CKO) mutant mice and their floxed exon 2 ephrin-B2 (Efnb2fl/fl) littermate controls for further experiments.


Nociceptor-expressed ephrin-B2 regulates inflammatory and neuropathic pain.

Zhao J, Yuan G, Cendan CM, Nassar MA, Lagerström MC, Kullander K, Gavazzi I, Wood JN - Mol Pain (2010)

Exon 2 of ephrin-B2 was deleted in DRG in Efnb2 CKO mice. (A) Diagram showing the ephrin-B2 wild-type locus, the targeted locus before and after Cre excision, Nav1.8 wild-type and Nav1.8-Cre locus. Exons are represented as numbered boxes. The loxP site (blank triangles) and the PCR primers (black arrows) are indicated. (B) Genotyping analysis with PCR. The DRGs genomic DNA from Efnb2 CKO mice, Efnb2fl/fl controls, heterozygous floxed exon 2 ephrin-B2 (Efnb2fl/+) mice and C57BL/6 wild-type (WT) mice were examined with PCR. The wild-type band (wt), floxed band (floxed) and Cre band (cre) were amplified with primer sets a/b, a/c and d/e respectively. The knockout band (ko) was found only from Efnb2 CKO mutant mice.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2992507&req=5

Figure 1: Exon 2 of ephrin-B2 was deleted in DRG in Efnb2 CKO mice. (A) Diagram showing the ephrin-B2 wild-type locus, the targeted locus before and after Cre excision, Nav1.8 wild-type and Nav1.8-Cre locus. Exons are represented as numbered boxes. The loxP site (blank triangles) and the PCR primers (black arrows) are indicated. (B) Genotyping analysis with PCR. The DRGs genomic DNA from Efnb2 CKO mice, Efnb2fl/fl controls, heterozygous floxed exon 2 ephrin-B2 (Efnb2fl/+) mice and C57BL/6 wild-type (WT) mice were examined with PCR. The wild-type band (wt), floxed band (floxed) and Cre band (cre) were amplified with primer sets a/b, a/c and d/e respectively. The knockout band (ko) was found only from Efnb2 CKO mutant mice.
Mentions: We therefore tested a floxed exon 2 ephrin-B2 mouse [17], and crossed the mouse with Nav1.8-Cre. Figure 1A shows the ephrin-B2 locus, loxP sites and position of PCR primers. Using PCR analysis, we examined the Cre excision in CKO mice. The result shows that knockout band (400 bp) was clearly apparent from DRG DNA in the CKO mice (Figure 1B). We therefore used the exon 2 ephrin-B2 conditional knockout (Efnb2 CKO) mutant mice and their floxed exon 2 ephrin-B2 (Efnb2fl/fl) littermate controls for further experiments.

Bottom Line: Formalin-induced pain behavior was attenuated in the second phase, and this correlated with diminished tyrosine phosphorylation of N-methyl-D-aspartic acid (NMDA) receptor subunit NR2B in the dorsal horn.Thermal hyperalgesia and mechanical allodynia were significantly reduced in the Seltzer model of neuropathic pain.Presynaptic ephrin-B2 expression thus plays an important role in regulating inflammatory pain through the regulation of synaptic plasticity in the dorsal horn and is also involved in the pathogenesis of some types of neuropathic pain.

View Article: PubMed Central - HTML - PubMed

Affiliation: Molecular Nociception Group, Wolfson Institute for Biomedical Research, Cruciform Building, University College London, London WC1E 6BT, UK.

ABSTRACT

Background: EphB receptors and their ephrin-B ligands play an important role in nervous system development, as well as synapse formation and plasticity in the adult brain. Recent studies show that intrathecal treatment with EphB-receptor activator ephrinB2-Fc induced thermal hyperalgesia and mechanical allodynia in rat, indicating that ephrin-B2 in small dorsal root ganglia (DRG) neurons and EphB receptors in the spinal cord modulate pain processing. To examine the role of ephrin-B2 in peripheral pain pathways, we deleted ephrin-B2 in Nav1.8+ nociceptive sensory neurons with the Cre-loxP system. Sensory neuron numbers and terminals were examined using neuronal makers. Pain behavior in acute, inflammatory and neuropathic pain models was assessed in the ephrin-B2 conditional knockout (CKO) mice. We also investigated the c-Fos expression and NMDA receptor NR2B phosphorylation in ephrin-B2 CKO mice and littermate controls.

Results: The ephrin-B2 CKO mice were healthy with no sensory neuron loss. However, pain-related behavior was substantially altered. Although acute pain behavior and motor co-ordination were normal, inflammatory pain was attenuated in ephrin-B2 mutant mice. Complete Freund's adjuvant (CFA)-induced mechanical hyperalgesia was halved. Formalin-induced pain behavior was attenuated in the second phase, and this correlated with diminished tyrosine phosphorylation of N-methyl-D-aspartic acid (NMDA) receptor subunit NR2B in the dorsal horn. Thermal hyperalgesia and mechanical allodynia were significantly reduced in the Seltzer model of neuropathic pain.

Conclusions: Presynaptic ephrin-B2 expression thus plays an important role in regulating inflammatory pain through the regulation of synaptic plasticity in the dorsal horn and is also involved in the pathogenesis of some types of neuropathic pain.

Show MeSH
Related in: MedlinePlus