Anti-isoDGR Antibody Inhibits Atherosclerosis Induced by Western Diet in ApoE ^-/- mice

Background

Degenerative protein modifications (DPMs) accumulate with aging and can alter biomolecule structure and function, including via spontaneous conversion of Asn-Gly-Arg (NGR) to isoAsp-Gly-Arg (isoDGR) motifs that can bind integrins and drive chronic inflammation.

Since isoDGR-modified extracellular matrix proteins are enriched in atherosclerosis and have been associated with rupture-prone plaque characteristics, we hypothesized that antibody neutralisation can inhibit key pathological features including atherosclerotic vascular plaque formation and metabolic dysfunction.

Methods

We first examined Pcmt1 ^-/- mice which rapidly accumulate isoDGR due to lack of the corresponding repair enzyme to assess the extent of vascular protein damage. We then treated 6-8 week old atherosclerosis-prone ( ApoE ^-/- ) mice which were fed a high-fat Western diet (WD) with weekly dose of 1mg/kg isoDGR-specific monoclonal antibody (isoDGR-mAb) or isotype-matched control (while on diet) for 2 months duration. A regular chow-fed ApoE ^-/- group served as baseline control. Aortic atherosclerotic burden, plaque composition, systemic inflammation, lipid profiles, hepatic steatosis, and metabolic parameters (indirect calorimetry) were assessed.

Results

Pcmt1 ^-/- mice displayed extensive isoDGR deposition and degeneration of the aortic wall, linking this DPM to vascular structural damage. In the ApoE ^-/- mice, WD induced large aortic root plaques with abundant isoDGR and macrophage infiltration. IsoDGR-mAb treatment decreased plaque size by ∼30% with reduced lipid and collagen content ( p=0 . 001) . Furthermore, plaques in treated mice contained significantly fewer CD68+ macrophages that also exhibited limited activation. Systemically, isoDGR-mAb modified lipoprotein profiles by decreasing atherogenic VLDL/IDL/LDL cholesterol ( p=0 . 04) while slightly increasing HDL, accompanied by a reduction in circulating inflammatory proteins. IsoDGR-mAb also protected against hepatic lipid accumulation which was reduced by ∼60% in treated animals ( p<0 . 001 ), with indirect calorimetry confirming ∼30% higher oxygen consumption and energy expenditure without change in food intake or physical activity.

Conclusion

We identified isoDGR as a key pathological factor involved in the progression of atherosclerosis. Remarkably, isoDGR neutralization diminished plaque inflammation and improved atherosclerotic plaque stability. Our findings support isoDGR neutralization as a promising therapeutic strategy to mitigate both atherosclerosis and aging-associated metabolic dysfunction.