Anesthesiologist Chi Mei Medical Center, Tainan, Taiwan Tainan, Tainan
Background: Recent research has highlighted the crucial role of microglia in neuropathic pain development, with Colony Stimulating Factor 1 (CSF1) being a significant factor. Guan Z et al. found that nerve damage increases CSF1 production from injured neurons, activating microglial CSF1 receptors and leading to microglial activation and pain onset. However, the specific miRNAs and genes involved in this process remain unexplored.
Purpose/Objectives: To address this, the expression profiles of miRNAs and mRNA in CSF1- activated microglia were analyzed with microarray and validated to explore the key modulators for neuropathic pain.
Methods: Primary cultured microglia were exposed to either 100 ng/ml purified CSF1or PBS for 16 hours at 37℃ after being maintained in serum-free media overnight. Subsequently, CSF1-activated microglia were collected for miRNA and mRNA profiling using Next-Generation Sequencing (NGS). An expression level filter was applied to miRNAs and mRNAs, requiring a p-value less than 0.05 and a 1.5-fold change in either direction.
Results: Following an inverse matching integration approach, we identified the top 50 highly expressed and the bottom 60 lowly expressed mRNAs for further investigation of enriched biological functions. Among the highly expressed mRNAs, a robust association with the TNFα pathway was discovered, while the lowly expressed mRNAs exhibited a significant link to Glycosaminoglycans (GAGs) metabolism. Specifically, miR652-5p, 672-5p, and 455-3p were found to target the upregulated genes associated with cell proliferation and the TNFα pathway, whereas the upregulation of miR-222-3p, miR-702-5p, miR-877, and miR- 644-2-5p was associated with the downregulation of GAG- related genes. Activated microglia were observed to facilitate the removal of GAGs, contributing to neuropathic pain. Additionally, relatively low expression levels of miRNAs (miR-34a-5p, 34b-5p, 449a-5p) corresponding to the CSF1 receptor (CSF1R) were observed.
Conclusions/Implications for future research and/or clinical care: The newly identified miRNAs and their target genes-TNF-α, GAGs, and CSF1R- offer promising new targets for the treatment of neuropathic pain.
