Intercepting IRE1 kinase-FMRP signaling prevents atherosclerosis progression

Area of Science:

• Molecular Biology
• Cell Biology
• Immunology

Background:

• Fragile X Mental Retardation protein (FMRP) is an RNA-binding protein crucial for intellectual development.
• Endoplasmic reticulum (ER) stress is implicated in various diseases, including atherosclerosis.
• Macrophage cholesterol homeostasis and efferocytosis are key processes in preventing atherosclerosis.

Purpose of the Study:

• To investigate the role of ER stress in regulating FMRP activity.
• To elucidate the mechanism by which ER stress affects macrophage function.
• To explore the therapeutic potential of targeting ER stress pathways in atherosclerosis.

Main Methods:

• Western blotting to detect FMRP phosphorylation.
• Macrophage cholesterol efflux and efferocytosis assays.
• Atherosclerosis mouse models with FMRP deficiency or IRE1 inhibition.

Main Results:

• ER stress induces FMRP phosphorylation via Inositol requiring enzyme-1 (IRE1) kinase activation.
• This phosphorylation suppresses macrophage cholesterol efflux and efferocytosis.
• FMRP deficiency or IRE1 inhibition improves macrophage function and reduces atherosclerosis in mice.

Conclusions:

• ER stress-induced IRE1 kinase activity impairs macrophage cholesterol homeostasis and efferocytosis.
• Targeting IRE1 kinase activity offers a novel therapeutic strategy for atherosclerosis.
• FMRP plays a critical role in mediating the effects of ER stress on macrophages.