Zhiqiang Pan1, Zhou-Ya Xue, Guo-Fang Li, Meng-Lan Sun, Ming Zhang, Ling-Yun Hao, Qian-Qian Tang, Li-Jiao Zhu, Jun-Li Cao. 1. From Jiangsu Province Key Laboratory of Anesthesiology (Z.P., Z.-Y.X., G.-F.L., M.-L.S., M.Z., L.-Y.H., Q.-Q.T., L.-J.Z., J.-L.C.) and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology (Z.P., Z.-Y.X., G.-F.L., M.-L.S., M.Z., L.-Y.H., Q.-Q.T., L.-J.Z., J.-L.C.), Xuzhou Medical University, Xuzhou; and Department of Anesthesiology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou (J.-L.C.), China.
Abstract
BACKGROUND: Ten-eleven translocation methylcytosine dioxygenase converts 5-methylcytosine in DNA to 5-hydroxymethylcytosine, which plays an important role in gene transcription. Although 5-hydroxymethylcytosine is enriched in mammalian neurons, its regulatory function in nociceptive information processing is unknown. METHODS: The global levels of 5-hydroxymethylcytosine and ten-eleven translocation methylcytosine dioxygenase were measured in spinal cords in mice treated with complete Freund's adjuvant. Immunoblotting, immunohistochemistry, and behavioral tests were used to explore the downstream ten-eleven translocation methylcytosine dioxygenase-dependent signaling pathway. RESULTS: Complete Freund's adjuvant-induced nociception increased the mean levels (± SD) of spinal 5-hydroxymethylcytosine (178 ± 34 vs. 100 ± 21; P = 0.0019), ten-eleven translocation methylcytosine dioxygenase-1 (0.52 ± 0.11 vs. 0.36 ± 0.064; P = 0.0088), and ten-eleven translocation methylcytosine dioxygenase-3 (0.61 ± 0.13 vs. 0.39 ± 0.08; P = 0.0083) compared with levels in control mice (n = 6/group). The knockdown of ten-eleven translocation methylcytosine dioxygenase-1 or ten-eleven translocation methylcytosine dioxygenase-3 alleviated thermal hyperalgesia and mechanical allodynia, whereas overexpression cytosinethem in naïve mice (n = 6/group). Down-regulation of spinal ten-eleven translocation methylcytosine dioxygenase-1 and ten-eleven translocation methylcytosine dioxygenase-3 also reversed the increases in Fos expression (123 ± 26 vs. 294 ± 6; P = 0.0031; and 140 ± 21 vs. 294 ± 60; P = 0.0043, respectively; n = 6/group), 5-hydroxymethylcytosine levels in the Stat3 promoter (75 ± 16.1 vs. 156 ± 28.9; P = 0.0043; and 91 ± 19.1 vs. 156 ± 28.9; P = 0.0066, respectively; n = 5/group), and consequent Stat3 expression (93 ± 19.6 vs. 137 ± 27.5; P = 0.035; and 72 ± 15.2 vs. 137 ± 27.5; P = 0.0028, respectively; n = 5/group) in complete Freund's adjuvant-treated mice. CONCLUSIONS: This study reveals a novel epigenetic mechanism for ten-eleven translocation methylcytosine dioxygenase-1 and ten-eleven translocation methylcytosine dioxygenase-3 in the modulation of spinal nociceptive information via targeting of Stat3.
BACKGROUND: Ten-eleven translocation methylcytosine dioxygenase converts 5-methylcytosine in DNA to 5-hydroxymethylcytosine, which plays an important role in gene transcription. Although 5-hydroxymethylcytosine is enriched in mammalian neurons, its regulatory function in nociceptive information processing is unknown. METHODS: The global levels of 5-hydroxymethylcytosine and ten-eleven translocation methylcytosine dioxygenase were measured in spinal cords in mice treated with complete Freund's adjuvant. Immunoblotting, immunohistochemistry, and behavioral tests were used to explore the downstream ten-eleven translocation methylcytosine dioxygenase-dependent signaling pathway. RESULTS: Complete Freund's adjuvant-induced nociception increased the mean levels (± SD) of spinal 5-hydroxymethylcytosine (178 ± 34 vs. 100 ± 21; P = 0.0019), ten-eleven translocation methylcytosine dioxygenase-1 (0.52 ± 0.11 vs. 0.36 ± 0.064; P = 0.0088), and ten-eleven translocation methylcytosine dioxygenase-3 (0.61 ± 0.13 vs. 0.39 ± 0.08; P = 0.0083) compared with levels in control mice (n = 6/group). The knockdown of ten-eleven translocation methylcytosine dioxygenase-1 or ten-eleven translocation methylcytosine dioxygenase-3 alleviated thermal hyperalgesia and mechanical allodynia, whereas overexpression cytosinethem in naïve mice (n = 6/group). Down-regulation of spinal ten-eleven translocation methylcytosine dioxygenase-1 and ten-eleven translocation methylcytosine dioxygenase-3 also reversed the increases in Fos expression (123 ± 26 vs. 294 ± 6; P = 0.0031; and 140 ± 21 vs. 294 ± 60; P = 0.0043, respectively; n = 6/group), 5-hydroxymethylcytosine levels in the Stat3 promoter (75 ± 16.1 vs. 156 ± 28.9; P = 0.0043; and 91 ± 19.1 vs. 156 ± 28.9; P = 0.0066, respectively; n = 5/group), and consequent Stat3 expression (93 ± 19.6 vs. 137 ± 27.5; P = 0.035; and 72 ± 15.2 vs. 137 ± 27.5; P = 0.0028, respectively; n = 5/group) in complete Freund's adjuvant-treated mice. CONCLUSIONS: This study reveals a novel epigenetic mechanism for ten-eleven translocation methylcytosine dioxygenase-1 and ten-eleven translocation methylcytosine dioxygenase-3 in the modulation of spinal nociceptive information via targeting of Stat3.