Oxidative stress triggers neuronal injury and mouse pain sensitization by up-regulating TDP-43 to activate mtDNA-cGAS/STING pathway
10.16016/j.2097-0927.202403103
- VernacularTitle:氧化应激通过TDP-43激活mtDNA-cGAS/STING通路诱发神经元损伤和小鼠痛觉敏化
- Author:
Li LI
1
;
Penghui HUANG
;
Jian CUI
Author Information
1. 400038 重庆,陆军军医大学(第三军医大学)第一附属医院疼痛科
- Keywords:
neuropathic pain;
TDP-43;
cGAS/STING pathway;
mtDNA;
oxidative stress
- From:
Journal of Army Medical University
2024;46(18):2036-2045
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the role and possible mechanisms of transactive response DNA binding protein 43 (TDP-43)in mediating neuronal injury induced by oxidative stress in mouse neuro-2a (N2a)cells and mouse pain sensitization.Methods ①To evaluate the optimal induction concentration,N2a cells were treated with different concentrations of H2O2,and the cells were divided into control group,200,400 and 800 μmol/L H2O2 groups.②To assess the optimal induction duration,N2a cells were treated with 400 μmol/L H2O2,and the cells were divided into control group,and the cell groups treated for 6,12 and 24 h,respectively.③To validate the mitochondrial DNA (mtDNA)release pathway,cyclosporin A (CsA) was used to inhibit the mitochondrial permeability transition pore (mPTP),and the cells were divided into control group,24 h H2O2 group and 24 h H2O2+CsA group.④To validate TDP-43-mediated cellular damage,the cells were divided into control group,24 h H2O2 group and 24 h H2O2+siTDP-43 group.⑤Cell viability was assessed using CCK-8 assay,while cell proliferation was determined using EdU assay.Western blot analysis was employed to examine the expression levels of TDP-43,neuronal nuclei (NeuN),cyclic GMP-AMP synthase (cGAS),and stimulator of interferon genes (STING).qPCR was utilized to measure the release of mtDNA.Immunostaining was conducted to observe intracellular expression of TDP-43,and Calcein AM staining was employed to evaluate mPTP opening status.⑥To elucidate the role of TDP-43 in neuropathic pain (NP),24 healthy SPF male C57BL/6J mice (6～8 weeks old,25～30 g)were randomly divided into control group,chronic constriction injury (CCI)group,and CCI+siTDP-43 group.In 1 d before and 7,14 and 21 d after surgery,intrathecal injections of siTDP-43 were administered.Mechanical and thermal pain thresholds of the mice were assessed using von Frey filaments and radiant heat,respectively,on 1 preoperatively and 1,3,5,7,14 and 21 d postoperatively.Immunofluorescence assay was conducted on 21 d postoperatively to examine the changes in TDP-43 and NeuN in the lumbar spinal dorsal horn (L5-L6).Results Oxidative stress induced a significant increase in TDP-43 protein level in N2a cells,prompted mtDNA release through mPTP,markedly up-regulated the expression of cGAS and STING,and consequently impacted the viability of N2a cells (P<0.05).CsA treatment inhibited mPTP channel opening and thus effectively blocked mtDNA release (P<0.05),down-regulated TDP-43 and thus significantly reduced mtDNA release,suppressed the expression of cGAS and STING,and finally restored the proliferation ability of N2a cells (P<0.05).The mechanical and thermal pain thresholds exhibited a significant decrease since 5 d after CCI,which then persisted until 21 d (P<0.05).The expression of TDP-43 in spinal cord dorsal horn neurons was increased in the mice in 21 d after CCI (P<0.05),and intrathecal injection of siRNA inhibited TDP-43 expression and effectively increased the mechanical and thermal pain thresholds in the CCI mice (P<0.05).Conclusion Oxidative stress induces an up-regulation in TDP-43 protein in neurons,which stimulates the release of mtDNA into the cytoplasm through mPTP,and subsequently activates the cGAS/STING pathway,and finally,results in neuronal injury and pain sensitization in CCI mice.
