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Updated: Feb 25, 2026
Detection of MicroRNAs in Microglia by Real-time PCR in Normal CNS and During Neuroinflammation
Published on: July 23, 2012
MicroRNA-181 Variants Regulate T Cell Phenotype in the Context of Autoimmune Neuroinflammation
Samira Ghorbani1,2, Farideh Talebi1, Wing Fuk Chan3
1Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Background:
Recent studies have revealed that multiple sclerosis (MS) lesions have distinct microRNA (miRNA) expression profiles. miR-181 family members show altered expression in MS tissues although their participation in MS pathogenesis remains uncertain. Herein, we investigated the involvement of miR-181a and miR-181b in the pathogenesis of MS and its animal model, experimental autoimmune encephalomyelitis (EAE).
Methods:
miR-181a and -b levels were measured in the central nervous system (CNS) of patients with MS and mice with EAE as well as relevant leukocyte cultures by real-time RT-PCR. To examine the role of the miRNAs in leukocyte differentiation and function, miR-181a and -b mimic sequences were transfected into cultured primary macrophages and purified CD4+ T cells which were then analyzed by RT-PCR and flow cytometry. Luciferase reporter assays were performed to investigate the interaction of miR-181a and -b with the 3'-UTR of potential target transcripts, and the expression of target genes was measured in the CNS of EAE mice, activated lymphocytes, and macrophages.
Results:
Expression analyses revealed a significant decrease in miR-181a and -b levels in brain white matter from MS patients as well as in spinal cords of EAE mice during the acute and chronic phases of disease. Suppression of miR-181a was observed following antigen-specific or polyclonal activation of lymphocytes as well as in macrophages following LPS treatment. Overexpression of miR-181a and -b mimic sequences reduced proinflammatory gene expression in macrophages and polarization toward M1 phenotype. miR-181a and -b mimic sequences inhibited Th1 generation in CD4+ T cells and miR-181a mimic sequences also promoted Treg differentiation. Luciferase assays revealed Suppressor of mothers against decapentaplegic 7 (Smad7), as a direct target of miR-181a and -b.
Conclusion:
Our data highlight the anti-inflammatory actions of miR-181a and -b in the context of autoimmune neuroinflammation. miR-181a and -b influence differentiation of T helper cell and activation of macrophages, providing potential therapeutic options for controlling inflammation in MS.
Insights
MicroRNAs miR-181a and miR-181b show reduced expression in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). Their restoration suppresses inflammation and influences immune cell differentiation, offering potential MS therapeutic strategies.
Area of Science:
- Neuroimmunology
- Molecular Biology
- Genetics
Background:
- Multiple sclerosis (MS) lesions exhibit distinct microRNA (miRNA) expression profiles.
- Altered expression of miR-181 family members in MS tissues suggests a role in pathogenesis, though not fully elucidated.
- This study investigates the specific involvement of miR-181a and miR-181b in MS and its animal model, experimental autoimmune encephalomyelitis (EAE).
Purpose of the Study:
- To investigate the role of miR-181a and miR-181b in the pathogenesis of multiple sclerosis (MS).
- To examine the impact of miR-181a and miR-181b on immune cell differentiation and function in the context of autoimmune neuroinflammation.
- To identify potential therapeutic targets for controlling inflammation in MS.
Main Methods:
- Quantification of miR-181a and miR-181b levels in central nervous system (CNS) tissues from MS patients and EAE mice using real-time RT-PCR.
- Transfection of miR-181a and miR-181b mimics into primary macrophages and CD4+ T cells to assess effects on differentiation and gene expression via RT-PCR and flow cytometry.
- Luciferase reporter assays to identify direct targets of miR-181a and miR-181b, with subsequent validation in relevant cell types and disease models.
Main Results:
- Significant downregulation of miR-181a and miR-181b was observed in MS patient brain white matter and EAE mouse spinal cords during active and chronic disease phases.
- Overexpression of miR-181a and miR-181b mimics reduced pro-inflammatory gene expression and M1 polarization in macrophages.
- miR-181a and miR-181b mimic transfection inhibited Th1 cell generation and promoted regulatory T cell (Treg) differentiation in CD4+ T cells.
- Suppressor of mothers against decapentaplegic 7 (Smad7) was identified as a direct target of miR-181a and miR-181b.
Conclusions:
- Data indicate significant anti-inflammatory actions of miR-181a and miR-181b in autoimmune neuroinflammation.
- These miRNAs modulate T helper cell differentiation and macrophage activation, crucial processes in MS pathogenesis.
- Restoring miR-181a and miR-181b levels presents a potential therapeutic strategy for managing inflammation in multiple sclerosis.
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