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Updated: Jul 30, 2025
Detection of MicroRNAs in Microglia by Real-time PCR in Normal CNS and During Neuroinflammation
Published on: July 23, 2012
Upregulated miR-125b mitigates inflammation, astrocyte activation, and dysfunction of spinal cord injury by
Xianhu Yue1, Mingyong Gu1, Tanghong Jia2
1Department of Orthopedics, The 960th Hospital of the Joint Logistics Support Force of the Chinese People's Liberation Army, Jinan City, Shandong Province, China.
Background:
Since the abnormal expression of miR-125b in spinal cord injury (SCI) and the regulatory effect of miR-125b on the MAPK pathway have been expounded, we attempt to investigate whether miR-125b exerts a regulatory effect on SCI by modulating the MAPK pathway.
Method:
A SCI rat model was established. The rats were treated with miR-125b antagomir or agomir, and their motor function affected by miR-125b was further detected by Basso-Beattie-Bresnahan (BBB) scoring. The histopathological changes and neuronal loss in the spinal cord were evaluated using hematoxylin-eosin and Nissl staining. Microglia-conditioned medium (MCM) was prepared and further used to treat the astrocytes, the activation of which was evaluated via immunofluorescence staining. The expressions of miR-125b, inflammation-related factors (IL-6, IL-1β, TNF-α, and IL-10), and MAPK pathway-related proteins (p38, ERK1/2, and JNK1/2 as well as their phosphorylated (p) forms) in the spinal cord, serum, and MCM-treated astrocytes of rats were determined by reverse-transcription quantitative polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay, and Western blot.
Result:
MiR-125b was lowly expressed in SCI-modeled rats. MiR-125b downregulation aggravated the impaired motor function, the disorder within the tissue, astrocyte activation, and neuron loss in the spinal cord tissues of SCI-modeled rats, while miR-125b upregulation did oppositely. MiR-125b downregulation enhanced the levels of IL-6, IL-1β, TNF-α, p38, p-p38, p-ERK1/2, and p-JNK1/2, whilst reducing that of IL-10. Contrarily, miR-125b upregulation exerted the opposite effects in SCI-modeled rats and MCM-treated astrocytes.
Conclusion:
Up-regulation of miR-125b mitigates inflammation, astrocyte activation, and dysfunction in SCI by inactivating the MAPK pathway.
Insights
Upregulating miR-125b improves motor function and reduces inflammation and astrocyte activation in spinal cord injury (SCI) by inhibiting the MAPK pathway. This study highlights miR-125b as a potential therapeutic target for SCI.
Area of Science:
- Neuroscience
- Molecular Biology
- Regenerative Medicine
Background:
- Abnormal microRNA-125b (miR-125b) expression is observed in spinal cord injury (SCI).
- miR-125b is known to regulate the mitogen-activated protein kinase (MAPK) pathway.
Purpose of the Study:
- To investigate the regulatory role of miR-125b in SCI.
- To determine if miR-125b modulates the MAPK pathway to affect SCI outcomes.
Main Methods:
- Established a rat model of spinal cord injury (SCI).
- Administered miR-125b antagomir or agomir to rats.
- Assessed motor function using Basso-Beattie-Bresnahan (BBB) scoring.
- Evaluated spinal cord histopathology and neuronal loss.
- Measured expressions of miR-125b, inflammatory factors, and MAPK pathway proteins using RT-qPCR, ELISA, and Western blot.
Main Results:
- miR-125b was downregulated in SCI rats.
- Downregulation of miR-125b worsened motor function, spinal cord tissue damage, astrocyte activation, and neuron loss.
- Upregulation of miR-125b showed opposite, beneficial effects.
- miR-125b levels correlated with inflammatory factors and MAPK pathway activation.
Conclusions:
- Upregulation of miR-125b mitigates inflammation, astrocyte activation, and dysfunction in SCI.
- miR-125b exerts its therapeutic effects by inactivating the MAPK pathway.
- miR-125b represents a potential therapeutic target for spinal cord injury.
