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Published on: August 6, 2019
MicroRNA-181b attenuates lipopolysaccharide-induced inflammatory responses in pulpitis via the PLAU/AKT/NF-κB axis
Tiantian Meng1, Xinpai Liu1, Jing Zhang1
1College & Hospital of Stomatology, Anhui Medical University, Key Lab. of Oral Diseases Research of Anhui Province, 69# Mei Shan Road, Hefei 230032, Anhui, China.
Objective:
This study aimed to investigate the role and underlying mechanisms of microRNA (miRNA)-181b in the inflammatory response in pulpitis.
Methods:
Quantitative reverse-transcription polymerase chain reaction (qRT-PCR), fluorescence in situ hybridization (FISH), and immunofluorescence techniques were used to determine the miRNA-181b and urokinase-type plasminogen activator (PLAU) expression levels in inflamed human dental pulp tissues (HDPTs) and lipopolysaccharide (LPS)-stimulated human dental pulp cells (hDPCs). The targets of miRNA-181b were identified and confirmed using a bioinformatics analysis, RNA sequencing, and dual-luciferase gene reporter assays. The effect of miRNA-181b or PLAU on proinflammatory cytokine expression in hDPCs was examined using qRT-PCR and western blotting. RNA sequencing was conducted to examine the signaling pathways implicated in miRNA-181b-mediated pulpitis. Western blotting and qRT-PCR were used to determine the miRNA-181b /PLAU/AKT/NF-κB signaling axis in pulpitis. A rat pulpitis model was created to observe the histopathological changes in the dental pulp tissue after the topical application of miRNA-181b agomir.
Results:
A significant decrease in miRNA-181b and an increase in PLAU were observed in HDPTs compared to the healthy controls, and these two factors showed a negative correlation. MiRNA-181b directly targeted PLAU. The miRNA-181b inhibitor resulted in a significant upregulation of IL-1β, IL-6 and TNF-α, whereas the knockdown of PLAU reversed this proinflammatory effect. Conversely, PLAU overexpression prevented the anti-inflammatory effects of the miRNA-181b mimics. Mechanistically, miRNA-181b inhibited the AKT/NF-κB pathway by targeting PLAU. In vivo application of the miRNA-181b agomir to inflamed pulp tissue alleviated inflammation.
Conclusion:
MiRNA-181b targets PLAU, negatively regulating pro-inflammatory cytokine expression via the AKT/NF-κB signaling pathway.
Insights
MicroRNA-181b, a key regulator, targets PLAU (urokinase-type plasminogen activator) to reduce inflammation in pulpitis. This study reveals miRNA-181b
Area of Science:
- Oral Biology
- Molecular Biology
- Immunology
Background:
- Pulpitis, an inflammatory condition of the dental pulp, is associated with dysregulated inflammatory responses.
- MicroRNAs (miRNAs) play crucial roles in regulating gene expression and cellular processes, including inflammation.
- Understanding the specific roles of miRNAs in pulpitis is essential for developing targeted therapies.
Purpose of the Study:
- To investigate the role of microRNA (miRNA)-181b in the inflammatory response during pulpitis.
- To elucidate the underlying molecular mechanisms, including target identification and signaling pathways involved.
- To evaluate the therapeutic potential of miRNA-181b in a pulpitis model.
Main Methods:
- Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and fluorescence in situ hybridization (FISH) to assess miRNA and mRNA expression.
- Bioinformatics analysis, RNA sequencing, and dual-luciferase reporter assays to identify and confirm miRNA targets.
- In vitro (cell culture) and in vivo (rat model) experiments to evaluate the functional effects of miRNA-181b and its target on inflammation.
Main Results:
- Decreased miRNA-181b and increased urokinase-type plasminogen activator (PLAU) expression were observed in inflamed dental pulp tissues.
- miRNA-181b directly targets PLAU, and this interaction negatively regulates pro-inflammatory cytokines (IL-1β, IL-6, TNF-α).
- miRNA-181b inhibits the AKT/NF-κB signaling pathway by targeting PLAU, and its in vivo administration alleviated pulpitis inflammation.
Conclusions:
- MiRNA-181b acts as a negative regulator of inflammation in pulpitis by targeting PLAU.
- The miRNA-181b/PLAU axis modulates the AKT/NF-κB signaling pathway, influencing pro-inflammatory cytokine production.
- MiRNA-181b demonstrates therapeutic potential for managing pulpitis.
