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Published on: October 12, 2017
miR-155 inhibits oxidized low-density lipoprotein-induced apoptosis of RAW264.7 cells
Abstract:
Macrophage apoptosis is a prominent feature of advanced atherosclerotic plaques. Here, we examined the hypothesis that the apoptotic machinery is regulated by microRNA-155 (miR-155). Constitutive expression of miR-155 was detected in RAW264.7 cells, which was increased following stimulation with oxidized low-density lipoprotein (OxLDL) in a dose- and time-dependent manner. OxLDL-treated RAW264.7 cells showed a marked time- and dose-dependent increase in apoptosis, which was suppressed in the presence of mimics and increased with antagonists of miR-155. Bioinformatics analysis revealed Fas-associated death domain-containing protein (FADD) as a putative target of miR-155. Luciferase reporter assay and Western blot further disclosed that miR-155 inhibits FADD expression by directly targeting the 3'-UTR region. We propose that miR-155 attenuates the macrophage apoptosis, at least in part, through FADD regulation, since forced expression of FADD blocked the ability of miR-155 to inhibit apoptosis. Our results collectively suggest that miR-155 attenuates apoptosis of OxLDL-mediated RAW264.7 cells by targeting FADD, supporting a possible therapeutic role in atherosclerosis.
Insights
MicroRNA-155 (miR-155) regulates macrophage apoptosis in atherosclerosis. This study shows miR-155 targets FADD, attenuating apoptosis in oxidized LDL-stimulated cells, suggesting a therapeutic role.
Area of Science:
- Biochemistry
- Molecular Biology
- Cardiovascular Research
Background:
- Macrophage apoptosis is a key feature of advanced atherosclerotic plaques.
- MicroRNAs are emerging as critical regulators of cellular processes, including apoptosis.
Purpose of the Study:
- To investigate the role of microRNA-155 (miR-155) in regulating macrophage apoptosis.
- To identify the molecular targets of miR-155 involved in this process.
Main Methods:
- Stimulation of RAW264.7 cells with oxidized low-density lipoprotein (OxLDL).
- Assessment of apoptosis using miR-155 mimics and antagonists.
- Bioinformatics analysis, luciferase reporter assays, and Western blotting to identify and validate miR-155 targets.
- Forced expression of Fas-associated death domain-containing protein (FADD) to confirm its role.
Main Results:
- OxLDL stimulation increased miR-155 expression and induced macrophage apoptosis in a dose- and time-dependent manner.
- miR-155 mimics suppressed OxLDL-induced apoptosis, while antagonists increased it.
- Fas-associated death domain-containing protein (FADD) was identified as a direct target of miR-155, with miR-155 inhibiting FADD expression.
- Forced expression of FADD reversed the anti-apoptotic effect of miR-155.
Conclusions:
- miR-155 attenuates OxLDL-mediated macrophage apoptosis by targeting FADD.
- These findings highlight a novel regulatory mechanism in atherosclerosis.
- miR-155 targeting FADD presents a potential therapeutic strategy for atherosclerosis.