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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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Related in: MedlinePlus

MeCP2 antibody from Sigma wrongly labels astrocytic processes in the superficial dorsal horn. A, Colocalization of MeCP2 (green; Sigma antibody) and astrocytes (red) in the superficial dorsal horn of naïve rat. B, Images of dorsal horn sections of MeCP2 knock out animals (gift from A.Bird) stained with anti-MeCP2 antibody from Sigma (1) and from Millipore (2). (3) Dorsal horn of wild type animals (C57BL/6) stained with the Millipore anti-MeCP2 antibody. Scale bar, 20 μm.
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Figure 5: MeCP2 antibody from Sigma wrongly labels astrocytic processes in the superficial dorsal horn. A, Colocalization of MeCP2 (green; Sigma antibody) and astrocytes (red) in the superficial dorsal horn of naïve rat. B, Images of dorsal horn sections of MeCP2 knock out animals (gift from A.Bird) stained with anti-MeCP2 antibody from Sigma (1) and from Millipore (2). (3) Dorsal horn of wild type animals (C57BL/6) stained with the Millipore anti-MeCP2 antibody. Scale bar, 20 μm.

Mentions: We began our study using an antibody against MeCP2 from Sigma. While we only expected a specific nuclear stain, we observed a clear labelling of astrocytic cytoplasm in the rat superficial dorsal horn (Figure 5A). In order to ascertain the validity of this stain, we used tissue from universal MeCP2 knock-out (KO) animals (gift from A. Bird) and found out that the antibody we were using was also labelling astrocytic-like processes in the dorsal horn of MeCP2 KO mice (Figure 5B1), suggesting that this was a non-specific stain. In contrast, the antibody directed against MeCP2 purchased from Millipore only showed a specific nuclear stain in wild-type animals (Figure 5B2 and 5B3). This antibody was therefore used for the rest of this study.


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)

MeCP2 antibody from Sigma wrongly labels astrocytic processes in the superficial dorsal horn. A, Colocalization of MeCP2 (green; Sigma antibody) and astrocytes (red) in the superficial dorsal horn of naïve rat. B, Images of dorsal horn sections of MeCP2 knock out animals (gift from A.Bird) stained with anti-MeCP2 antibody from Sigma (1) and from Millipore (2). (3) Dorsal horn of wild type animals (C57BL/6) stained with the Millipore anti-MeCP2 antibody. Scale bar, 20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: MeCP2 antibody from Sigma wrongly labels astrocytic processes in the superficial dorsal horn. A, Colocalization of MeCP2 (green; Sigma antibody) and astrocytes (red) in the superficial dorsal horn of naïve rat. B, Images of dorsal horn sections of MeCP2 knock out animals (gift from A.Bird) stained with anti-MeCP2 antibody from Sigma (1) and from Millipore (2). (3) Dorsal horn of wild type animals (C57BL/6) stained with the Millipore anti-MeCP2 antibody. Scale bar, 20 μm.
Mentions: We began our study using an antibody against MeCP2 from Sigma. While we only expected a specific nuclear stain, we observed a clear labelling of astrocytic cytoplasm in the rat superficial dorsal horn (Figure 5A). In order to ascertain the validity of this stain, we used tissue from universal MeCP2 knock-out (KO) animals (gift from A. Bird) and found out that the antibody we were using was also labelling astrocytic-like processes in the dorsal horn of MeCP2 KO mice (Figure 5B1), suggesting that this was a non-specific stain. In contrast, the antibody directed against MeCP2 purchased from Millipore only showed a specific nuclear stain in wild-type animals (Figure 5B2 and 5B3). This antibody was therefore used for the rest of this study.

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