The transcription factor Tbx5-dependent epigenetic modification contributes to neuropathic allodynia by activating TRPV1 expression in dorsal horn.

Abstract

Nerve injury can induce aberrant changes in the spine; these changes are due to, or at least partly governed by, transcription factors that contribute to the genesis of neuropathic allodynia. Here, we showed that spinal nerve ligation (SNL, a clinical neuropathic allodynia model) increased the expression of the transcription factor Tbx5 in the injured dorsal horn in male Sprague Dawley rats. In contrast, blocking this upregulation alleviated SNL-induced mechanical allodynia, and there was no apparent effect on locomotor function. Moreover, SNL-induced Tbx5 upregulation promoted the recruitment and interaction of GATA4 and Brd4 by enhancing its binding activity to H3K9Ac, which was enriched at the Trpv1 promotor, leading to an increase in TRPV1 transcription and the development of neuropathic allodynia. In addition, nerve injury-induced expression of Fbxo3, which abates Fbxl2-dependent Tbx5 ubiquitination, promoted the subsequent Tbx5-dependent epigenetic modification of TRPV1 expression during SNL-induced neuropathic allodynia. Collectively, our findings indicated that spinal Tbx5-dependent TRPV1 transcription signaling contributes to the development of neuropathic allodynia via Fbxo3-dependent Fbxl2 ubiquitination and degradation. Thus, we propose a potential medical treatment strategy for neuropathic allodynia by targeting Tbx5.Significance Statement Nerve injury-induced epigenetic changes in Tbx5 enhance TRPV1 expression in the dorsal horn, with Tbx5 recruiting GATA4 and Brd4 for epigenetic modification of TRPV1. The Fbxo3-mediated Fbxl2 ubiquitination pathway stabilizes Tbx5, increasing its transcriptional activity and enhancing TRPV1 expression, contributing to the initiation and maintenance of neuropathic pain via epigenetic reprogramming.