SUR1, newly expressed in astrocytes, mediates neuropathic pain in a mouse model of peripheral nerve injury
PublisherSAGE Publications Inc.
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AbstractBackground: Neuropathic pain following peripheral nerve injury (PNI) is linked to neuroinflammation in the spinal cord marked by astrocyte activation and upregulation of interleukin 6 (IL-6), chemokine (C-C motif) ligand 2 (CCL2) and chemokine (C-X-C motif) ligand 1 (CXCL1), with inhibition of each individually being beneficial in pain models. Methods: Wild type (WT) mice and mice with global or pGfap-cre- or pGFAP-cre/ERT2-driven Abcc8/SUR1 deletion or global Trpm4 deletion underwent unilateral sciatic nerve cuffing. WT mice received prophylactic (starting on post-operative day [pod]-0) or therapeutic (starting on pod-21) administration of the SUR1 antagonist, glibenclamide (10 mg IP) daily. We measured mechanical and thermal sensitivity using von Frey filaments and an automated Hargreaves method. Spinal cord tissues were evaluated for SUR1-TRPM4, IL-6, CCL2 and CXCL1. Results: Sciatic nerve cuffing in WT mice resulted in pain behaviors (mechanical allodynia, thermal hyperalgesia) and newly upregulated SUR1-TRPM4 in dorsal horn astrocytes. Global and pGfap-cre-driven Abcc8 deletion and global Trpm4 deletion prevented development of pain behaviors. In mice with Abcc8 deletion regulated by pGFAP-cre/ERT2, after pain behaviors were established, delayed silencing of Abcc8 by tamoxifen resulted in gradual improvement over the next 14 days. After PNI, leakage of the blood-spinal barrier allowed entry of glibenclamide into the affected dorsal horn. Daily repeated administration of glibenclamide, both prophylactically and after allodynia was established, prevented or reduced allodynia. The salutary effects of glibenclamide on pain behaviors correlated with reduced expression of IL-6, CCL2 and CXCL1 by dorsal horn astrocytes. Conclusion: SUR1-TRPM4 may represent a novel non-addicting target for neuropathic pain. Copyright The Author(s) 2021.
SponsorsThe author(s) disclosed receipt of the following ?nancial support for the research, authorship, and/or publication of this article: This work was supported by grants (to JMS) from the Department of Veterans Affairs (I01RX003060) and from the NINDS (R01NS105633), a grant (to VG) from NINDS (R01NS107262) and a grant (to CAS and JMS) from the Kahlert Foundation, Sykesville, MD.
CCL2 or CXCL1
sulfonylurea receptor 1 (SUR1)
Identifier to cite or link to this itemhttp://hdl.handle.net/10713/15157