Macrophage Exosomes Resolve Atherosclerosis by Regulating Hematopoiesis and Inflammation via MicroRNA Cargo

Area of Science:

• Immunology
• Cardiovascular Biology
• Molecular Medicine

Background:

• Vascular inflammation and atherosclerosis present significant therapeutic challenges.
• Developing strategies for resolving these conditions is crucial.

Purpose of the Study:

• To investigate the therapeutic potential of exosomes derived from interleukin-4 (IL-4) polarized bone marrow-derived macrophages (BMDM-IL-4-exo) for atherosclerosis.
• To elucidate the anti-inflammatory mechanisms mediated by microRNA cargo within these exosomes.

Main Methods:

• Characterization of microRNA content in BMDM-exo and BMDM-IL-4-exo.
• Assessment of exosomal microRNA effects on NF-κB and TNF-α signaling pathways in recipient macrophages.
• In vivo studies using Apoe-/- mice on a Western diet, treated with BMDM-IL-4-exo, to evaluate atherosclerosis progression.

Main Results:

• BMDM-IL-4-exo exhibit enriched anti-inflammatory microRNAs (miR-99a/146b/378a) compared to naive BMDM-exo.
• These microRNAs suppress inflammation by targeting NF-κB and TNF-α signaling pathways and promote M2 macrophage polarization.
• In vivo treatment reduced bone marrow hematopoiesis, circulating myeloid cells, and aortic root lesion macrophages, leading to necrotic core reduction and atheroma stabilization.

Conclusions:

• BMDM-IL-4-exo represent a promising cell-free therapeutic approach for atherosclerosis.
• The therapeutic effects are mediated by the delivery of anti-inflammatory microRNAs targeting key inflammatory pathways.
• This strategy holds potential for treating atherosclerosis and other inflammatory disorders.