Open AccessUpregulation of CXCR 4 through promoter demethylation contributes to inflammatory hyperalgesia in rats
Author(s) -
Li Feng,
Xue ZhouYa,
Yuan Yuan,
Huang SaiSai,
Fan YiHui,
Zhu Xiang,
Wei Lei
Publication year - 2018
Publication title -
cns neuroscience and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 69
eISSN - 1755-5949
pISSN - 1755-5930
DOI - 10.1111/cns.12845
Subject(s) - pyrrolidine dithiocarbamate , dna methylation , methylated dna immunoprecipitation , methylation , chromatin immunoprecipitation , bisulfite sequencing , downregulation and upregulation , hyperalgesia , gene expression , cancer research , inflammation , chemokine , microbiology and biotechnology , pharmacology , promoter , biology , immunology , receptor , gene , nociception , nf κb , biochemistry
Summary Aim and methods Chronic pain associated with inflammation is a common clinical problem, and the underlying mechanisms yet are incompletely defined. DNA methylation has been implicated in the pathogenesis of chronic pain. However, the specific genes regulated by DNA methylation under inflammatory pain condition remain largely unknown. Here, we investigated how chemokine receptor CXCR 4 expression is regulated by DNA methylation and how it contributes to inflammatory pain induced by complete Freund's adjuvant ( CFA ) in rats. Results Intraplantar injection of CFA could not only induce significant hyperalgesia in rats, but also significantly increase the expression of CXCR 4 mRNA and protein in the dorsal root ganglion ( DRG ). Intrathecal injection of CXCR 4 antagonist AMD 3100 significantly relieved hyperalgesia in inflammatory rats in a time‐ and dose‐dependent manner. Bisulfite sequencing and methylation‐specific PCR demonstrate that CFA injection led to a significant demethylation of CpG island at CXCR 4 gene promoter. Consistently, the expression of DNMT 3b was significantly downregulated after CFA injection. Online software prediction reveals three binding sites of p65 in the CpG island of CXCR 4 gene promoter, which has confirmed by the chromatin immunoprecipitation assay, CFA treatment significantly increases the recruitment of p65 to CXCR 4 gene promoter. Inhibition of NF ‐ kB signaling using p65 inhibitor pyrrolidine dithiocarbamate significantly prevented the increases of the CXCR 4 expression. Conclusion Upregulation of CXCR 4 expression due to promoter demethylation followed by increased recruitment of p65 to promoter of CXCR 4 gene contributes to inflammatory hyperalgesia. These findings provide a theoretical basis for the treatment of chronic pain from an epigenetic perspective.