In vivo inhibition of miR-125b modulates monocyte trafficking through the CCR7 receptor and attenuates atherosclerosis
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Background
Atherosclerosis (ATH) is a chronic systemic inflammatory disease affecting the vessel wall, wherein regulating non-coding RNAs play a crucial role. We previously demonstrated that miR-125b is upregulated in ATH and is a main regulator of cholesterol metabolism in macrophages. Herein we hypothesized that inhibiting miR-125b may attenuate ATH.
Methods and results
In the ApoE -/- mice model fed with a high fat diet for 14 weeks, we inhibited miR-125b using an antagomiR over a 4-week period. We observed a significant reduction in plaque size, accompanied by diminished infiltration of F4/80 macrophages and attenuation of NF-κB + activation within plaques. We explored the mechanism using a Vas-on-Chip adhesion assay using Human Aortic Endothelial Cells (HAoEC) stimulated with TNFα. We observed an impairment in the trafficking of miR-125b transfected THP-1 monocytes, accompanied by the downregulation of the CD11b/CD18 integrin and the CCR7 receptor. Furthermore, we demonstrated a direct regulation of the CCR7 receptor by miR-125b using a reporter plasmid construct (p_CCR7.WT) containing the 3’UTR region of CCR7 gene fused with a luciferase coding sequence. In addition, miR-125b transfected monocytes inhibited CCR7 cell migration induced by the CCL21 ligand but did not affect migration induced by others ligands such as MCP1. Finally, we confirmed the downregulation of CCR7 in coronary plaques in both ApoE -/- mice and patients with coronary artery disease.
Conclusions
Inhibiting miR-125b offers a novel therapeutic approach for ameliorating ATH that results in a reduction of macrophage content and plaque lesion size. This improvement occurs through the enhancement of monocyte trafficking via CCR7 that facilitates the exit of foam cells from the plaque.
CLINICAL PERSPECTIVE
What is New?
- We found evidences of a new therapeutic approach for atherosclerosis, in which miR-125b inhibition reduces macrophage content and plaque size.
- We described the molecular mechanism underlying miR-125b, which involves regulating of monocyte trafficking to plaques and the downregulation of the chemokine receptor CCR7. CCR7 plays a crucial role in facilitating the egress of macrophages and foam cells from plaques, and its downregulation contribute to progression of ATH.
- The results have been validated in a cohort of patients with coronary artery disease, where CCR7 expression was reduced in plaques.
What are the clinical implications?
- We highlight the pivotal role of monocyte trafficking in the inflammatory mechanism of atherosclerosis. Managing miR-125b/CCR7 signaling may improve the resolution of ATH promoting the exit of foam cells from plaque.
- Inhibition of miR-125b in plaque macrophages represents a novel and promising therapeutic approach for cardiovascular disease.
