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Updated: Oct 10, 2025
Detection of MicroRNAs in Microglia by Real-time PCR in Normal CNS and During Neuroinflammation
Published on: July 23, 2012
MicroRNA miR-27b-3p regulate microglial inflammation response and cell apoptosis by inhibiting A20 (TNF-α-induced
Liping Li1,2, Chao Qi3, Yuanyuan Liu4,5
1Department of Orthopedic Surgery, The Affiliated Qingdao Central Hospital of Qingdao University, Qingdao, Shandong, China.
Abstract:
Inflammatory reaction exerts a pivotal role in secondary damage after cerebral hemorrhage and spinal cord injury. miRNAs can both promote and inhibit inflammatory actions among microglial cells. The objective of the present paper was to figure out whether miR-27b-3p produced regulatory effects during processes of microglial inflammation. Lipopolysaccharides (LPS) were used to prepare microglial activation models. Following miR-27b-3p overexpression and interference, the RNA and protein levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β were subjected to real-time fluorescent quantitative PCR (qPCR) and western blot assays, respectively. Cellular apoptosis was subjected to flow cytometry and miR-27b-3p target genes were visualized using a dual luciferase reporter system for verification. The levels of TNF-α, IL-6, and IL-1β mRNA in miR-27b-3p-overexpressed microglial cells were markedly increased compared to the control. Apoptosis of microglial cells was increased markedly in the overexpressed miR-27b-3p group compared to the negative control. Conversely, a different result was presented in the microglial transfected with miR-27b-3p inhibitors. The downregulation of A20, a miR-27b-3p target gene, mediated levels of TNF-α, IL-6, and IL-1β. Furthermore, A20 reduced microglial apoptosis. These data revealed that miR-27b-3p could mediate not only microglia activation but also neuroinflammation via downregulating A20 expression. Thus, miR-27b-3p is regarded as gene therapy in treating cerebral hemorrhage and spinal cord injury.
Insights
MicroRNA-27b-3p promotes microglial inflammation and apoptosis by downregulating A20. This finding suggests miR-27b-3p as a potential gene therapy target for cerebral hemorrhage and spinal cord injury.
Area of Science:
- Neuroscience
- Molecular Biology
- Immunology
Background:
- Inflammatory responses are critical in secondary damage following central nervous system injuries like cerebral hemorrhage and spinal cord injury.
- Microglia, the resident immune cells of the brain, play a dual role in inflammation, capable of both promoting and inhibiting inflammatory processes.
- MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression and are implicated in various cellular functions, including inflammation.
Purpose of the Study:
- To investigate the regulatory role of microRNA-27b-3p (miR-27b-3p) in microglial inflammatory responses.
- To determine if miR-27b-3p influences the expression of key inflammatory mediators and cell apoptosis in microglia.
Main Methods:
- Microglial activation models were established using lipopolysaccharides (LPS).
- miR-27b-3p was overexpressed and inhibited in microglial cells.
- Quantitative PCR and Western blot were used to measure RNA and protein levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β).
- Flow cytometry assessed cellular apoptosis, and a dual luciferase reporter system verified miR-27b-3p target genes.
Main Results:
- Overexpression of miR-27b-3p significantly increased the mRNA and protein levels of TNF-α, IL-6, and IL-1β in microglial cells.
- Increased microglial apoptosis was observed in cells with overexpressed miR-27b-3p.
- Conversely, inhibiting miR-27b-3p led to decreased inflammatory markers and apoptosis.
- A20 was identified as a direct target gene of miR-27b-3p, and its downregulation mediated the observed effects on inflammation and apoptosis.
Conclusions:
- miR-27b-3p promotes microglial activation and neuroinflammation by downregulating the expression of A20.
- These findings highlight miR-27b-3p as a potential therapeutic target for managing neuroinflammation in conditions such as cerebral hemorrhage and spinal cord injury.
- miR-27b-3p may serve as a novel gene therapy strategy for treating secondary damage in CNS injuries.
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