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The expression of spinal methyl-CpG-binding protein 2, DNA methyltransferases and histone deacetylases is modulated in persistent pain states.

Tochiki KK, Cunningham J, Hunt SP, Géranton SM - Mol Pain (2012)

Bottom Line: Recently, we have found that MeCP2 activity had a crucial role in the pattern of gene expression seen in the superficial dorsal horn rapidly after injection of Complete Freund's Adjuvant (CFA) in the rat ankle joint.However, there were no significant changes in the expression of the MeCP2 targets that we had previously shown are regulated in the early time points following CFA injection in the ankle joint.Our results strongly suggest that changes in chromatin compaction, regulated by the binding of MeCP2 complexes to methylated DNA, are involved in the modulation of gene expression in the superficial dorsal horn and dorsal root ganglia during the maintenance of persistent pain states.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK.

ABSTRACT

Background: DNA CpG methylation is carried out by DNA methyltransferases and induces chromatin remodeling and gene silencing through a transcription repressor complex comprising the methyl-CpG-binding protein 2 (MeCP2) and a subset of histone deacetylases. Recently, we have found that MeCP2 activity had a crucial role in the pattern of gene expression seen in the superficial dorsal horn rapidly after injection of Complete Freund's Adjuvant (CFA) in the rat ankle joint. The aim of the present study was to analyse the changes in expression of MeCP2, DNA methyltransferases and a subset of histone deacetylases in the superficial dorsal horn during the maintenance phase of persistent pain states. In this process, the cell specific expression of MeCP2 was also investigated.

Results: Using immunohistochemistry, we found that neurones, oligodendrocytes and astrocytes expressed MeCP2. Microglia, oligodendrocyte precursor cells and Schwann cells never showed any positive stain for MeCP2. Quantitative analyses showed that MeCP2 expression was increased in the superficial dorsal horn 7 days following CFA injection in the ankle joint but decreased 7 days following spared nerve injury. Overall, the expression of DNA methyltransferases and a subset of histone deacetylases followed the same pattern of expression. However, there were no significant changes in the expression of the MeCP2 targets that we had previously shown are regulated in the early time points following CFA injection in the ankle joint. Finally, the expression of MeCP2 was also down regulated in damaged dorsal root ganglion neurones following spared nerve injury.

Conclusion: Our results strongly suggest that changes in chromatin compaction, regulated by the binding of MeCP2 complexes to methylated DNA, are involved in the modulation of gene expression in the superficial dorsal horn and dorsal root ganglia during the maintenance of persistent pain states.

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All neurones express MeCP2 in the rat superficial dorsal horn. Confocal images of rat superficial dorsal horn sections. Colocalization of MeCP2 (green; Millipore antibody) and NeuN (red). MeCP2 can be seen within the nucleus of all neurones (arrows). However, some MeCP2 staining is clearly non-neuronal (arrow heads). Pictures show single focal plane. Scale bars, 1) 50 μm and 2) 20 μm.
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Figure 1: All neurones express MeCP2 in the rat superficial dorsal horn. Confocal images of rat superficial dorsal horn sections. Colocalization of MeCP2 (green; Millipore antibody) and NeuN (red). MeCP2 can be seen within the nucleus of all neurones (arrows). However, some MeCP2 staining is clearly non-neuronal (arrow heads). Pictures show single focal plane. Scale bars, 1) 50 μm and 2) 20 μm.

Mentions: The neuronal and glial expression of MeCP2 was investigated in the superficial dorsal horn of animals that had undergone SNI surgery 7 days before perfusion, animals that had received a CFA injection in the ankle joint 7 days before perfusion and sham animals for both groups. While all neurones (anti-neuronal nuclei (NeuN) positive cells) expressed MeCP2 in all conditions (Figure 1), expression of MeCP2 in glial cells was at lower levels. Oligodendrocytes (anti-Adenomatosis Polyposis Coli (APC, CC-1) positive cells; Figure 2A) and astrocytes (anti-Glial Fibrillary Acidic Protein (GFAP) positive cells; Figure 2B) expressed MeCP2 only when saturating the signal from neuronal MeCP2. However, microglia (anti-Ionized calcium-binding adaptor molecule 1 (IBa1) positive cells) and oligodendrocyte precursor cells (OPCs; NG2 positive cells) never showed any MeCP2 stain (Figure 2C and 2D, respectively).


The expression of spinal methyl-CpG-binding protein 2, DNA methyltransferases and histone deacetylases is modulated in persistent pain states.

Tochiki KK, Cunningham J, Hunt SP, Géranton SM - Mol Pain (2012)

All neurones express MeCP2 in the rat superficial dorsal horn. Confocal images of rat superficial dorsal horn sections. Colocalization of MeCP2 (green; Millipore antibody) and NeuN (red). MeCP2 can be seen within the nucleus of all neurones (arrows). However, some MeCP2 staining is clearly non-neuronal (arrow heads). Pictures show single focal plane. Scale bars, 1) 50 μm and 2) 20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3351747&req=5

Figure 1: All neurones express MeCP2 in the rat superficial dorsal horn. Confocal images of rat superficial dorsal horn sections. Colocalization of MeCP2 (green; Millipore antibody) and NeuN (red). MeCP2 can be seen within the nucleus of all neurones (arrows). However, some MeCP2 staining is clearly non-neuronal (arrow heads). Pictures show single focal plane. Scale bars, 1) 50 μm and 2) 20 μm.
Mentions: The neuronal and glial expression of MeCP2 was investigated in the superficial dorsal horn of animals that had undergone SNI surgery 7 days before perfusion, animals that had received a CFA injection in the ankle joint 7 days before perfusion and sham animals for both groups. While all neurones (anti-neuronal nuclei (NeuN) positive cells) expressed MeCP2 in all conditions (Figure 1), expression of MeCP2 in glial cells was at lower levels. Oligodendrocytes (anti-Adenomatosis Polyposis Coli (APC, CC-1) positive cells; Figure 2A) and astrocytes (anti-Glial Fibrillary Acidic Protein (GFAP) positive cells; Figure 2B) expressed MeCP2 only when saturating the signal from neuronal MeCP2. However, microglia (anti-Ionized calcium-binding adaptor molecule 1 (IBa1) positive cells) and oligodendrocyte precursor cells (OPCs; NG2 positive cells) never showed any MeCP2 stain (Figure 2C and 2D, respectively).

Bottom Line: Recently, we have found that MeCP2 activity had a crucial role in the pattern of gene expression seen in the superficial dorsal horn rapidly after injection of Complete Freund's Adjuvant (CFA) in the rat ankle joint.However, there were no significant changes in the expression of the MeCP2 targets that we had previously shown are regulated in the early time points following CFA injection in the ankle joint.Our results strongly suggest that changes in chromatin compaction, regulated by the binding of MeCP2 complexes to methylated DNA, are involved in the modulation of gene expression in the superficial dorsal horn and dorsal root ganglia during the maintenance of persistent pain states.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK.

ABSTRACT

Background: DNA CpG methylation is carried out by DNA methyltransferases and induces chromatin remodeling and gene silencing through a transcription repressor complex comprising the methyl-CpG-binding protein 2 (MeCP2) and a subset of histone deacetylases. Recently, we have found that MeCP2 activity had a crucial role in the pattern of gene expression seen in the superficial dorsal horn rapidly after injection of Complete Freund's Adjuvant (CFA) in the rat ankle joint. The aim of the present study was to analyse the changes in expression of MeCP2, DNA methyltransferases and a subset of histone deacetylases in the superficial dorsal horn during the maintenance phase of persistent pain states. In this process, the cell specific expression of MeCP2 was also investigated.

Results: Using immunohistochemistry, we found that neurones, oligodendrocytes and astrocytes expressed MeCP2. Microglia, oligodendrocyte precursor cells and Schwann cells never showed any positive stain for MeCP2. Quantitative analyses showed that MeCP2 expression was increased in the superficial dorsal horn 7 days following CFA injection in the ankle joint but decreased 7 days following spared nerve injury. Overall, the expression of DNA methyltransferases and a subset of histone deacetylases followed the same pattern of expression. However, there were no significant changes in the expression of the MeCP2 targets that we had previously shown are regulated in the early time points following CFA injection in the ankle joint. Finally, the expression of MeCP2 was also down regulated in damaged dorsal root ganglion neurones following spared nerve injury.

Conclusion: Our results strongly suggest that changes in chromatin compaction, regulated by the binding of MeCP2 complexes to methylated DNA, are involved in the modulation of gene expression in the superficial dorsal horn and dorsal root ganglia during the maintenance of persistent pain states.

Show MeSH
Related in: MedlinePlus