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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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Expression of MeCP2, DNMTs and HDACs increases within the dorsal horn 7 days following CFA injection in the ankle joint but decreases 7 days following SNI surgery. The expression of MeCP2, downstream targets, DNMTs and HDACs was quantified by RT-qPCR. Y axis represents mRNA expression as a percentage of control (sham animals). Data show mean ± SEM. *: P < 0.05 and ** P < 0.01 sham vs contra; # P < 0.05, ## P < 0.01 and ###: P < 0.001 sham vs ipsi; $ P < 0.05 ipsi vs contra. CFA: N = 5 in each group and SNI: N = 7 in each group.
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Figure 3: Expression of MeCP2, DNMTs and HDACs increases within the dorsal horn 7 days following CFA injection in the ankle joint but decreases 7 days following SNI surgery. The expression of MeCP2, downstream targets, DNMTs and HDACs was quantified by RT-qPCR. Y axis represents mRNA expression as a percentage of control (sham animals). Data show mean ± SEM. *: P < 0.05 and ** P < 0.01 sham vs contra; # P < 0.05, ## P < 0.01 and ###: P < 0.001 sham vs ipsi; $ P < 0.05 ipsi vs contra. CFA: N = 5 in each group and SNI: N = 7 in each group.

Mentions: MeCP2 expression in the superficial dorsal horn was analysed using RT-qPCR. MeCP2 isoforms e1 and e2 are generated by alternative splicing of exon 2 to produce proteins with differing N termini [27]. Both MeCP2 transcripts are expressed almost ubiquitously with higher expression of the e1 isoform in the brain [28]. MeCP2 isoforms were investigated using specific primers [29]. We found a bilateral increase in MeCP2 e1 but a unilateral increase of MeCP2 e2 in the contralateral side 7 days post CFA injection (Figure 3A and Table 1). We then investigated the expression of the genes that we had found were under MeCP2 control in the superficial dorsal horn shortly after CFA injection into the ankle joint. We found no significant change in SGK1, FKBP5 and SULT1a1 expression (Figure 3A and Table 1).


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)

Expression of MeCP2, DNMTs and HDACs increases within the dorsal horn 7 days following CFA injection in the ankle joint but decreases 7 days following SNI surgery. The expression of MeCP2, downstream targets, DNMTs and HDACs was quantified by RT-qPCR. Y axis represents mRNA expression as a percentage of control (sham animals). Data show mean ± SEM. *: P < 0.05 and ** P < 0.01 sham vs contra; # P < 0.05, ## P < 0.01 and ###: P < 0.001 sham vs ipsi; $ P < 0.05 ipsi vs contra. CFA: N = 5 in each group and SNI: N = 7 in each group.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Expression of MeCP2, DNMTs and HDACs increases within the dorsal horn 7 days following CFA injection in the ankle joint but decreases 7 days following SNI surgery. The expression of MeCP2, downstream targets, DNMTs and HDACs was quantified by RT-qPCR. Y axis represents mRNA expression as a percentage of control (sham animals). Data show mean ± SEM. *: P < 0.05 and ** P < 0.01 sham vs contra; # P < 0.05, ## P < 0.01 and ###: P < 0.001 sham vs ipsi; $ P < 0.05 ipsi vs contra. CFA: N = 5 in each group and SNI: N = 7 in each group.
Mentions: MeCP2 expression in the superficial dorsal horn was analysed using RT-qPCR. MeCP2 isoforms e1 and e2 are generated by alternative splicing of exon 2 to produce proteins with differing N termini [27]. Both MeCP2 transcripts are expressed almost ubiquitously with higher expression of the e1 isoform in the brain [28]. MeCP2 isoforms were investigated using specific primers [29]. We found a bilateral increase in MeCP2 e1 but a unilateral increase of MeCP2 e2 in the contralateral side 7 days post CFA injection (Figure 3A and Table 1). We then investigated the expression of the genes that we had found were under MeCP2 control in the superficial dorsal horn shortly after CFA injection into the ankle joint. We found no significant change in SGK1, FKBP5 and SULT1a1 expression (Figure 3A and Table 1).

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