Endothelial exosomes work as a functional mediator to activate macrophages

Area of Science:

• Cell Biology
• Immunology
• Cardiovascular Research

Background:

• Intercellular communication via exosomes is crucial in physiological and pathological processes.
• Endothelial cell (EC)-derived exosomes mediate information exchange and are implicated in atherosclerosis.
• The impact of inflamed EC exosomes on macrophage (Mϕ) function remains unclear.

Purpose of the Study:

• To investigate the effects of exosomes from tumor necrosis factor-α (TNF-α)-stimulated ECs (exo-T) on Mϕ function in vitro.
• To elucidate the underlying molecular mechanisms involving signaling pathways.

Main Methods:

• Characterization of exosomes (exo and exo-T) using TEM, NTA, and western blot.
• Assessing Mϕ polarization, lipid deposition, apoptosis, and migration via RT-qPCR, flow cytometry, and various assays.
• MicroRNA sequencing (miRNA-Seq) and bioinformatics analyses (GO, KEGG) to identify differentially expressed miRNAs and target genes.
• Immunoblotting to analyze protein phosphorylation in MAPK/NF-κB pathways.

Main Results:

• PKH67-labeled exo/exo-T were internalized by Mϕ.
• exo-T exposure skewed Mϕ to M1 subtype, increased lipid deposition, and promoted apoptosis, without significantly affecting migration.
• miRNA-Seq identified 104 differentially expressed miRNAs, with target genes enriched in metabolic and MAPK signaling pathways.
• exo-T treatment enhanced phosphorylation of MAPK/NF-κB-related proteins.

Conclusions:

• Inflamed endothelial exosomes (exo-T) act as functional mediators influencing Mϕ behavior.
• exo-T may activate Mϕ through the MAPK/NF-κB signaling pathways.
• This study provides insights into the role of endothelial exosomes in atherosclerosis pathophysiology.