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Updated: Dec 17, 2025
Identifying Microglia and Peripheral Infiltrating Macrophages in the Injured Spinal Cords Using Flow Cytometry
Published on: June 24, 2025
MicroRNA-21-5p promotes the inflammatory response after spinal cord injury by targeting PLAG1
1Department of Traumatic Orthopaedics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China. sdslyygkhk@126.com.
Objective:
The aim of this study was to investigate the expression level of microRNA-21-5p and its target gene PLAG1 in the serum of patients with spinal cord injury (SCI), as well as the role and mechanism of microRNA-21-5p in lipopolysaccharide-induced primary microglial inflammation.
Patients And Methods:
The levels of microRNA-21-5p and PLAG1 in the peripheral blood of 24 patients with spinal cord injury and 24 healthy people were examined by quantitative Polymerase Chain Reaction (qPCR) analysis. The expressions of inflammatory factors, including IL-1, IL-6 and TNF-α were measured by enzyme-linked immunosorbent assay (ELISA). After microglial BV2 cells were treated with different concentrations of LPS, microRNA-21-5p, and PLAG1 expressions were examined by qPCR, while IL-1, IL-6, and TNF-α levels in cell supernatant were measured by ELISA. Finally, the binding relationship between microRNA-21-5p and its target gene was analyzed by Luciferase reporter assay.
Results:
The data showed that microRNA-21-5p was upregulated in the serum of SCI patients, and also increased in LPS-treated cells, with a certain concentration dependence. On the contrary, PLAG1 was remarkably downregulated, suggesting that the above two genes were negatively correlated in SCI patients. ELISA results indicated that the knockdown of microRNA-21-5p or overexpression of PLAG1 reduced the levels of IL-1, IL-6 and TNF-α in BV2 cells. Meanwhile, microRNA-21-5p might be involved in regulating the inflammatory response of BV2 cells by modulating PLAG1.
Conclusions:
MicroRNA-21-5p promotes the inflammatory response after SCI by targeting PLAG1.
Insights
MicroRNA-21-5p is upregulated in spinal cord injury (SCI) patients and promotes inflammation by targeting PLAG1. This study investigated its role in SCI-related microglial inflammation.
Area of Science:
- Neuroscience
- Molecular Biology
- Immunology
Background:
- Spinal cord injury (SCI) triggers significant neuroinflammation.
- MicroRNAs play crucial roles in regulating cellular processes, including inflammation.
- Understanding the molecular mechanisms of SCI pathogenesis is vital for developing effective treatments.
Purpose of the Study:
- To investigate the expression of microRNA-21-5p and its target gene PLAG1 in spinal cord injury (SCI) patients.
- To elucidate the role and mechanism of microRNA-21-5p in lipopolysaccharide (LPS)-induced primary microglial inflammation.
- To explore the potential therapeutic targets for SCI-related inflammation.
Main Methods:
- Quantitative Polymerase Chain Reaction (qPCR) was used to measure microRNA-21-5p and PLAG1 levels in patient serum and cell models.
- Enzyme-linked immunosorbent assay (ELISA) quantified inflammatory factors (IL-1, IL-6, TNF-α).
- Luciferase reporter assay confirmed the binding relationship between microRNA-21-5p and PLAG1.
Main Results:
- MicroRNA-21-5p was upregulated in SCI patients' serum and LPS-treated microglial cells.
- PLAG1 expression was downregulated in SCI patients and negatively correlated with microRNA-21-5p.
- Knockdown of microRNA-21-5p or overexpression of PLAG1 reduced inflammatory cytokine levels.
Conclusions:
- MicroRNA-21-5p promotes microglial inflammation in the context of spinal cord injury.
- The mechanism involves the targeting of PLAG1 by microRNA-21-5p.
- MicroRNA-21-5p represents a potential therapeutic target for mitigating SCI-induced inflammation.
