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MicroRNA-494-3p alleviates inflammatory response in sepsis by targeting TLR6
1Department of Intensive Care Unit, Tianjin First Center Hospital, Tianjin, China. doulint@163.com.
Objective:
To clarify whether microRNA-494-3p could exert an anti-inflammation effect by suppressing the expression of toll-like receptor 6 (TLR6), thus inhibiting the development of sepsis.
Patients And Methods:
Plasma levels of microRNA-494-3p and TLR6 in sepsis patients and healthy controls were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Diagnostic potential of microRNA-494-3p in sepsis was evaluated by receiver operating characteristic (ROC) curve. In vitro macrophage inflammation model was established by lipopolysaccharides (LPS) induction in RAW264.7 cells. Expression levels of microRNA-494-3p, TLR6 and tumor necrosis factor-α (TNF-α) in LPS-induced RAW264.7 cells were observed. After transfection of microRNA-494-3p mimics in LPS-induced RAW264.7 cells, mRNA and protein levels of TNF-α were determined by qRT-PCR and Western blot, respectively. Meanwhile, cytoplasmic and nuclear fractions of nuclear factor-kappa B (NF-κB) p65 were respectively extracted for evaluating nuclear translocation of NF-κB p65 by Western blot analysis. Dual-luciferase reporter gene assay was performed to verify the binding between microRNA-494-3p and TLR6. Finally, rescue experiments were carried out to elucidate whether microRNA-494-3p attenuated sepsis-induced inflammation through degrading TLR6.
Results:
Plasma level of microRNA-494-3p in sepsis patients was markedly lower than healthy controls, while plasma level of TLR6 was conversely higher in sepsis patients. With the prolongation of LPS induction in RAW264.7 cells, expression levels of TLR6 and TNF-α gradually increased, whereas microRNA-494-3p expression decreased. Transfection of microRNA-494-3p mimics in RAW264.7 cells reduced TNF-α level, and inhibited nuclear translocation of NF-κB p65. TLR6 was found to be a target gene of microRNA-494-3p, and its expression was markedly downregulated by microRNA-494-3p overexpression. Finally, we proved that the inhibitory effects of microRNA-494-3p on TNF-α level and nuclear translocation of NF-κB p65 were reversed by TLR6.
Conclusions:
High expression of microRNA-494-3p attenuated sepsis-induced inflammatory response by degrading TLR6.
Insights
MicroRNA-494-3p levels are lower in sepsis patients and its overexpression reduces inflammation by targeting toll-like receptor 6 (TLR6). This suggests microRNA-494-3p can mitigate sepsis-induced inflammatory responses.
Area of Science:
- Molecular Biology
- Immunology
- Sepsis Pathophysiology
Background:
- Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection.
- Toll-like receptor 6 (TLR6) plays a crucial role in the inflammatory cascade during sepsis.
- MicroRNAs (miRNAs) are implicated in regulating inflammatory processes, but the role of specific miRNAs in sepsis requires further elucidation.
Purpose of the Study:
- To investigate the anti-inflammatory role of microRNA-494-3p in sepsis.
- To determine if microRNA-494-3p suppresses toll-like receptor 6 (TLR6) expression.
- To assess the potential of microRNA-494-3p as a therapeutic target for sepsis.
Main Methods:
- Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were used to measure miRNA and protein expression.
- An in vitro macrophage inflammation model was established using lipopolysaccharide (LPS) induction.
- Dual-luciferase reporter gene assay and rescue experiments were performed to confirm target interaction and functional effects.
Main Results:
- Plasma microRNA-494-3p was significantly lower, while TLR6 was higher in sepsis patients compared to healthy controls.
- Overexpression of microRNA-494-3p in LPS-induced macrophages reduced tumor necrosis factor-α (TNF-α) levels and inhibited nuclear factor-kappa B (NF-κB) p65 nuclear translocation.
- TLR6 was identified as a direct target of microRNA-494-3p, and its downregulation by microRNA-494-3p attenuated inflammatory responses.
Conclusions:
- MicroRNA-494-3p exerts an anti-inflammatory effect in sepsis by directly targeting and degrading TLR6.
- Downregulation of TLR6 by microRNA-494-3p inhibits key inflammatory signaling pathways.
- MicroRNA-494-3p holds potential as a therapeutic agent for mitigating sepsis-induced inflammation.
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