Journal Article

Huc-MSCs-derived exosomes attenuate inflammatory pain by regulating microglia pyroptosis and autophagy via the miR-146a-5p/TRAF6 axis

Kong, Erliang, Liu, Zhixiao, Wang, Yue, Yang, Mei, Li, Yongchang, Hua, Tong, Song, Honghao, Fu, Hailong, Deng, Mengqiu, Li, Jian, Yuan, Hongbin

2022

Overview

Background Chronic inflammatory pain significantly reduces the quality of life and lacks effective interventions. In recent years, human umbilical cord mesenchymal stem cells (huc-MSCs)-derived exosomes have been used to relieve neuropathic pain and other inflammatory diseases as a promising cell-free therapeutic strategy. However, the therapeutic value of huc-MSCs-derived exosomes in complete Freund's adjuvant (CFA)-induced inflammatory pain remains to be confirmed. In this study, we investigated the therapeutic effect and related mechanisms of huc-MSCs-derived exosomes in a chronic inflammatory pain model. Methods C57BL/6J male mice were used to establish a CFA-induced inflammatory pain model, and huc-MSCs-derived exosomes were intrathecally injected for 4 consecutive days. BV2 microglia cells were stimulated with lipopolysaccharide (LPS) plus adenosine triphosphate (ATP) to investigate the effect of huc-MSCs-derived exosomes on pyroptosis and autophagy. Bioinformatic analysis and rescue experiments were used to demonstrate the role of miR-146a-5p/ TRAF6 in regulating pyroptosis and autophagy. Western blotting, RT-qPCR, small interfering RNA and Yo-Pro-1 dye staining were performed to investigate the related mechanisms. Results Huc-MSCs-derived exosomes alleviated mechanical allodynia and thermal hyperalgesia in CFA-induced inflammatory pain. Furthermore, huc-MSCs-derived exosomes attenuated neuroinflammation by increasing the expression of autophagy-related proteins (LC3-II and beclin1) and inhibiting the activation of NLRP3 inflammasomes in the spinal cord dorsal horn. In vitro, NLRP3 inflammasome components (NLRP3, caspase1-p20, ASC) and gasdermin D (GSDMD-F, GSDMD-N) were inhibited in BV2 cells pretreated with huc-MSCs-derived exosomes. Western blot and Yo-Pro-1 dye staining demonstrated that 3-MA, an autophagy inhibitor, weakened the protective effect of huc-MSCs-derived exosomes on BV2 cell pyroptosis. Importantly, huc-MSCs-derived exosomes transfected with miR-146a-5p mimic promoted autophagy and inhibited BV2 cell pyroptosis. TRAF6, as a target gene of miR-146a-5p, was knocked down via small-interfering RNA, which increased pyroptosis and inhibited autophagy. Conclusion Huc-MSCs-derived exosomes attenuated inflammatory pain via miR-146a-5p/TRAF6, which increased the level of autophagy and inhibited pyroptosis. Graphical Abstract

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Adenosine triphosphate / Analgesics / Animals / ATP / Attenuation / Autophagy / Autophagy (Cytology) / Biotechnology / Care and treatment / Cell death / Chemistry / Chemistry and Materials Science / Chromosome 5 / Chronic pain / Dorsal horn / Drug withdrawal / Drugs / Dyes / Evaluation / Exosomes / Experiments / Freund's adjuvant / Health aspects / Huc-MSCs-derived exosomes / Humidity / Hyperalgesia / Inflammasomes / Inflammation / Inflammatory diseases / Inflammatory pain / Life sciences / Ligands / Lipopolysaccharides / Mesenchyme / Methods / Microglia / MicroRNA / Molecular Medicine / Nanotechnology / Narcotics / Neuralgia / Pain / Pain perception / Pathogens / Proteins / Pyroptosis / Quality of life / Ribonucleic acid / RNA / siRNA / Spinal cord / Spinal cord injuries / Staining / Stem cell transplantation / Stem cells / TRAF6 protein / Umbilical cord / Western blotting