Upregulation of TRPC6 Mediated by PAX6 Hypomethylation Is Involved in the Mechanical Allodynia Induced by Chemotherapeutics in Dorsal Root Ganglion

Abstract

Background Although the action mechanism of antineoplastic agents is different, oxaliplatin, paclitaxel, or bortezomib as first-line antineoplastic drugs can induce painful neuropathy. In rodents, mechanical allodynia is a common phenotype of painful neuropathy for 3 chemotherapeutics. However, whether there is a common molecular involved in the different chemotherapeutics-induced painful peripheral neuropathy remains unclear. Methods Mechanical allodynia was tested by von Frey hairs following i.p. injection of vehicle, oxaliplatin, paclitaxel, or bortezomib in Sprague-Dawley rats. Reduced representation bisulfite sequencing and methylated DNA immunoprecipitation were used to detect the change of DNA methylation. Western blot, quantitative polymerase chain reaction, chromatin immunoprecipitation, and immunohistochemistry were employed to explore the molecular mechanisms. Results In 3 chemotherapeutic models, oxaliplatin, paclitaxel, or bortezomib accordantly upregulated the expression of transient receptor potential cation channel, subfamily C6 (TRPC6) mRNA and protein without affecting the DNA methylation level of TRPC6 gene in DRG. Inhibition of TRPC6 by using TRPC6 siRNA (i.t., 10 consecutive days) relieved mechanical allodynia significantly following application of chemotherapeutics. Furthermore, the downregulated recruitment of DNA methyltransferase 3 beta (DNMT3b) at paired box protein 6 (PAX6) gene led to the hypomethylation of PAX6 gene and increased PAX6 expression. Finally, the increased PAX6 via binding to the TPRC6 promoter contributes to the TRPC6 increase and mechanical allodynia following chemotherapeutics treatment. Conclusions The TRPC6 upregulation through DNMT3b-mediated PAX6 gene hypomethylation participated in mechanical allodynia following application of different chemotherapeutic drugs.

The analgesic action of larixyl acetate, a potent TRPC6 inhibitor, in rat neuropathic pain model induced by spared nerve injury

“…9a, b and 10b, f), suggesting that TRPC6 plays an important role in the faciliation of neuropathic pain and microgliosis. These results are in concert with the recent studies demonstrating the role of TRPC6 in varied chronic pain, such as neuropathic pain, cancer pain and morphine induced pain [12,50,53]. Thus, TRPC6 may be an important and promising molecular target for the management of chronic pain.…”

Neuro-immune interactions in paclitaxel-induced peripheral neuropathy

“…Mechanical and heat hypersensitivity TRPA1 [65,69,70] Increased functional activity in terms of hypersensitivity to stimuli [65,69,70] Mechanical and cold hypersensitivity TRPC6 [71] Increased expression in DRG (through DNMT3b-mediated PAX6 gene hypomethylation) [71] Mechanical hypersensitivity TRPM8 [70] Increased functional activity in terms of hypersensitivity to stimuli [70] Mechanical and cold hypersensitivity Table 2. Increased expression of voltage-gated channels following paclitaxel treatment.…”

Long-Term Treatment with Bortezomib Induces Specific Methylation Changes in Differentiated Neuronal Cells

“…This analysis showed that DNA motifs targeted by several TFs, including mainly EBF, PAX, DLX, LHX, and HNF family members, as well as En1, Nkx6.1, PRDM1, and Nanog transcription factors, were statistically significantly enriched in the regions harboring BTZ-induced methylation changes ( q -value ≤ 0.05) ( Supplementary Table S5 ). All of these TFs have previously been linked to neurogenesis or neuronal differentiation [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]; most interestingly, the top two identified TFs, PAX6 and EBF2, have been shown to be associated with peripheral neuropathy [ 37 , 38 ].…”

“…The transcription factor binding sites that were enriched for the BTZ-induced methylation changes were EBF, PAX, DLX, LHX, and HNF family members, but also several other TFs, such as En1, Nkx6.1, PRDM1 and Nanog, all of which have previously been linked to neurogenesis or neuronal differentiation [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. The top hit in this analysis was for PAX6, which has been shown to contribute to the painful sensation, referred to as mechanical allodynia, following applications of different chemotherapeutics treatments, including BTZ [ 37 ]. The second top transcription factor, EBF2, was shown in in vivo studies to play a key role in neuronal migration and nerve development [ 38 ].…”