TET1 Overexpression Mitigates Neuropathic Pain Through Rescuing the Expression of μ-Opioid Receptor and Kv1.2 in the Primary Sensory Neurons
Peripheral nerve injury downregulates the expression of the μ-opioid receptor (MOR) and voltage-gated potassium channel subunit Kv1.2 by increasing their DNA methylation in the dorsal root ganglion (DRG). Ten-eleven translocation methylcytosine dioxygenase 1 (TET1) causes DNA demethylation. Given that DRG MOR and Kv1.2 downregulation contribute to neuropathic pain genesis, this study investigated the effect of DRG TET1 overexpression on neuropathic pain. Overexpression of TET1 in the DRG through microinjection of herpes simplex virus expressing full-length TET1 mRNA into the injured rat DRG significantly alleviated the fifth lumbar spinal nerve ligation (SNL)–induced pain hypersensitivities during the development and maintenance periods, without altering acute pain or locomotor function. This microinjection also restored morphine analgesia and attenuated morphine analgesic tolerance development after SNL. Mechanistically, TET1 microinjection rescued the expression of MOR and Kv1.2 by reducing the level of 5-methylcytosine and increasing the level of 5-hydroxymethylcytosine in the promoter and 5′ untranslated regions of the Oprml1 gene (encoding MOR) and in the promoter region of the Kcna2 gene (encoding Kv1.2) in the DRG ipsilateral to SNL. These findings suggest that DRG TET1 overexpression mitigated neuropathic pain likely through rescue of MOR and Kv1.2 expression in the ipsilateral DRG. Virus-mediated DRG delivery of TET1 may open a new avenue for neuropathic pain management.
KeywordsTET1 DNA demethylation μ-opioid receptor Kv1.2 dorsal root ganglion neuropathic pain
We appreciate Dr. Wanhong Zuo for the single-cell collection and acknowledge Ms. Jamie Bono for the assistance in the preparation of the manuscript. This work was supported by NIH grants (R01NS094664, R01NS094224, and R01DA033390) for YXT, the National Nature Science Foundation of China (81471352) for MC, and the Fundamental Research Funds for the Central Universities (2682016CX103) for GW.
Y.X.T. and M.C. conceived the project and supervised all experiments. Q.W., G.W., F.J., S.J., and Y.X.T. designed the project. Q.W., F.J., X.G., X.M., and S.J. performed the animal model, conducted behavioral experiments, and carried out microinjection and DRG culture. G.W., X.G., L.H., and F.J. carried out Western blot, chromatin immunoprecipitation, and PCR experiments. Z.P., Y.Y., and Q.M. helped with Western blot and chromatin immunoprecipitation experiments. S.W. constructed HSV-TET1 and carried out PCR. Q.W., S.J., M.C., and Y.X.T. analyzed the data. Q.W., M.C., and Y.X.T. wrote the manuscript. All of the authors read and discussed the manuscript.
Compliance with Ethical Standards
All procedures used were approved by the Animal Care and Use Committee at the Rutgers New Jersey Medical School (Newark, New Jersey).
The authors declare that they have no conflict of interest.
- 1.van HO, Austin SK, Khan RA, Smith BH, Torrance N (2014) Neuropathic pain in the general population: a systematic review of epidemiological studies. Pain 155: 654–662. S0304–3959(13)00610–6 doi: https://doi.org/10.1016/j.pain.2013.11.013.
- 7.Liang L, Zhao JY, Gu X, Wu S, Mo K, Xiong M, Bekker A, Tao YX (2016) G9a inhibits CREB-triggered expression of mu opioid receptor in primary sensory neurons following peripheral nerve injury. Mol Pain 12: 1–16.Google Scholar
- 8.Sun L, Zhao JY, Gu X, Liang L, Wu S, Mo K, Feng J, Guo W, Zhang J, Bekker A, Zhao X, Nestler EJ, Tao YX (2017) Nerve injury-induced epigenetic silencing of opioid receptors controlled by DNMT3a in primary afferent neurons. Pain 158: 1153–1165. doi: https://doi.org/10.1097/j.pain.0000000000000894.CrossRefGoogle Scholar
- 10.Stein C, Zollner C (2009) Opioids and sensory nerves. Handb Exp Pharmacol 495–518. doi: https://doi.org/10.1007/978-3-540-79090-7_14.
- 12.Fan L, Guan X, Wang W, Zhao JY, Zhang H, Tiwari V, Hoffman PN, Li M, Tao YX (2014) Impaired neuropathic pain and preserved acute pain in rats overexpressing voltage-gated potassium channel subunit Kv1.2 in primary afferent neurons. Mol Pain 10: 8. 1744-8069-10-8 doi: https://doi.org/10.1186/1744-8069-10-8.CrossRefGoogle Scholar
- 13.Zhao X, Tang Z, Zhang H, Atianjoh FE, Zhao JY, Liang L, Wang W, Guan X, Kao SC, Tiwari V, Gao YJ, Hoffman PN, Cui H, Li M, Dong X, Tao YX (2013) A long noncoding RNA contributes to neuropathic pain by silencing Kcna2 in primary afferent neurons. Nat Neurosci 16: 1024–1031. nn.3438. doi: https://doi.org/10.1038/nn.3438.CrossRefGoogle Scholar
- 14.Zhao JY, Liang L, Gu X, Li Z, Wu S, Sun L, Atianjoh FE, Feng J, Mo K, Jia S, Lutz BM, Bekker A, Nestler EJ, Tao YX (2017) DNA methyltransferase DNMT3a contributes to neuropathic pain by repressing Kcna2 in primary afferent neurons. Nat Commun 8: 14712. ncomms14712. https://doi.org/10.1038/ncomms14712.CrossRefGoogle Scholar
- 15.He YF, Li BZ, Li Z, Liu P, Wang Y, Tang Q, Ding J, Jia Y, Chen Z, Li L, Sun Y, Li X, Dai Q, Song CX, Zhang K, He C, Xu GL (2011) Tet-mediated formation of 5-carboxylcytosine and its excision by TDG in mammalian DNA. Science 333: 1303–1307. doi: https://doi.org/10.1126/science.1210944.CrossRefGoogle Scholar
- 19.Liaw WJ, Zhu XG, Yaster M, Johns RA, Gauda EB, Tao YX (2008) Distinct expression of synaptic NR2A and NR2B in the central nervous system and impaired morphine tolerance and physical dependence in mice deficient in postsynaptic density-93 protein. Mol Pain 4: 45. 1744-8069-4-45 doi: https://doi.org/10.1186/1744-8069-4-45.CrossRefGoogle Scholar
- 21.Park JS, Voitenko N, Petralia RS, Guan X, Xu JT, Steinberg JP, Takamiya K, Sotnik A, Kopach O, Huganir RL, Tao YX (2009) Persistent inflammation induces GluR2 internalization via NMDA receptor-triggered PKC activation in dorsal horn neurons. J Neurosci 29: 3206–3219. 29/10/3206 doi: https://doi.org/10.1523/JNEUROSCI.4514-08.2009.CrossRefGoogle Scholar
- 24.Zhang J, Liang L, Miao X, Wu S, Cao J, Tao B, Mao Q, Mo K, Xiong M, Lutz BM, Bekker A, Tao YX (2016) Contribution of the Suppressor of Variegation 3-9 Homolog 1 in Dorsal Root Ganglia and Spinal Cord Dorsal Horn to Nerve Injury-induced Nociceptive Hypersensitivity. Anesthesiology 125: 765–778. doi: https://doi.org/10.1097/ALN.0000000000001261.CrossRefGoogle Scholar
- 26.Eichten SR, Briskine R, Song J, Li Q, Swanson-Wagner R, Hermanson PJ, Waters AJ, Starr E, West PT, Tiffin P, Myers CL, Vaughn MW, Springer NM (2013) Epigenetic and genetic influences on DNA methylation variation in maize populations. Plant Cell 25: 2783–2797. doi: https://doi.org/10.1105/tpc.113.114793.CrossRefGoogle Scholar
- 34.Chamessian AG, Qadri YJ, Cummins M, Hendrickson M, Berta T, Buchheit T, Van d, V (2017) 5-Hydroxymethylcytosine (5hmC) and Ten-eleven translocation 1–3 (TET1–3) proteins in the dorsal root ganglia of mouse: Expression and dynamic regulation in neuropathic pain. Somatosens Mot Res 1–8. doi: https://doi.org/10.1080/08990220.2017.1292237.
- 36.Hsieh MC, Ho YC, Lai CY, Chou D, Wang HH, Chen GD, Lin TB, Peng HY (2017) Melatonin impedes Tet1-dependent mGluR5 promoter demethylation to relieve pain. J Pineal Res e12436. doi: https://doi.org/10.1111/jpi.12436.
- 38.Pan Z, Xue ZY, Li GF, Sun ML, Zhang M, Hao LY, Tang QQ, Zhu LJ, Cao JL (2017) DNA Hydroxymethylation by Ten-eleven Translocation Methylcytosine Dioxygenase 1 and 3 Regulates Nociceptive Sensitization in a Chronic Inflammatory Pain Model. Anesthesiology 127: 147–163. doi: https://doi.org/10.1097/ALN.0000000000001632.CrossRefGoogle Scholar
- 40.Maze I, Covington HE, III, Dietz DM, LaPlant Q, Renthal W, Russo SJ, Mechanic M, Mouzon E, Neve RL, Haggarty SJ, Ren Y, Sampath SC, Hurd YL, Greengard P, Tarakhovsky A, Schaefer A, Nestler EJ (2010) Essential role of the histone methyltransferase G9a in cocaine-induced plasticity. Science 327: 213–216. 327/5962/213. doi: https://doi.org/10.1126/science.1179438.CrossRefGoogle Scholar