Inhibition of spinal Rac1 attenuates chronic inflammatory pain by regulating the activation of astrocytes

Yantong Wan; Jieshu Zhou; Panpan Zhang; Xuemei Lin; Hao Li

doi:10.1016/j.cellsig.2023.110972

Inhibition of spinal Rac1 attenuates chronic inflammatory pain by regulating the activation of astrocytes

Cell Signal. 2024 Feb:114:110972. doi: 10.1016/j.cellsig.2023.110972. Epub 2023 Nov 18.

Authors

Yantong Wan¹, Jieshu Zhou¹, Panpan Zhang¹, Xuemei Lin², Hao Li³

Affiliations

¹ Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan, China.
² Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan, China. Electronic address: xuemeilin__scu@163.com.
³ Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan, China. Electronic address: lihao0510@163.com.

PMID: 37984604
DOI: 10.1016/j.cellsig.2023.110972

Abstract

Background: Spinal astrocyte-mediated neuroinflammation is an important mechanism for the maintenance of chronic inflammatory pain. Previous studies have investigated that Ras-related C3 botulinum toxin substrate 1 (Rac1) is closely related to astrocyte activation after central nervous system injury. However, the role of Rac1 in astrocyte activation in chronic inflammatory pain has not been reported.

Methods: Complete Freund's adjuvant (CFA)-induced chronic inflammatory pain model and LPS-stimulated astrocytes were used to investigate the role of Rac1 in astrocyte activation and the underlying mechanism. Rac1-interfering adeno-associated virus (AAV) targeting astrocytes was delivered to spinal astrocytes by intrathecal administration and a Rac1 specific inhibitor, NSC23766, was used to block cultured astrocytes. The glial fibrillary acidic protein (GFAP), proinflammatory cytokines, p-NF-κB, and nod-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome were detected by RT-qPCR, Western blotting, and immunofluorescence to investigate the activation of astrocytes.

Results: CFA induced spinal astrocyte activation and increased the expression of active Rac1 in spinal astrocytes. Knockdown of astrocyte Rac1 alleviated chronic inflammatory pain and inhibited astrocyte activation. Inhibition of Rac1 activation in cultured astrocytes decreased the expression of GFAP and proinflammatory cytokines. Knockdown of Rac1 inhibited the increase of expression of NLRP3 inflammasome and phosphorylation of NF-κB in the spinal lumbar enlargement after CFA injection. Similarly, the inhibition of Rac1 suppressed the increase of NLRP3 inflammasome and p-NF-κB protein level after LPS stimulation.

Conclusion: Knockdown of astrocyte Rac1 attenuated CFA-induced hyperalgesia and astrocyte activation possibly by blocking the expression of NLRP3 inflammasome and phosphorylation of NF-κB.

Keywords: Astrocyte; Chronic inflammatory pain; Rac1; Spinal.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Astrocytes / metabolism
Chronic Pain* / drug therapy
Chronic Pain* / metabolism
Cytokines / metabolism
Inflammasomes / metabolism
Inflammation / metabolism
Lipopolysaccharides / metabolism
Lipopolysaccharides / pharmacology
NF-kappa B / metabolism
NLR Family, Pyrin Domain-Containing 3 Protein* / metabolism
Rats
Rats, Sprague-Dawley
rac1 GTP-Binding Protein* / antagonists & inhibitors
rac1 GTP-Binding Protein* / metabolism

Substances

Cytokines
Inflammasomes
Lipopolysaccharides
NF-kappa B
NLR Family, Pyrin Domain-Containing 3 Protein
Rac1 protein, rat
NSC 23766
rac1 GTP-Binding Protein