HDL-associated phosphatidylserine blunts myeloid activation and protects from atherosclerosis

Lipids play a critical role in atherosclerosis. Low-density lipoprotein (LDL)-cholesterol and certain lipid classes like sphingomyelins are associated with inflammation and poor cardiovascular outcomes. Phosphatidylserine (PS), on the other hand, is a negatively charged anti-inflammatory phospholipid class involved in efferocytosis. In this study, we sought to investigate its anti-atherosclerotic properties through a combination of complementary human lipidomics analyses, in vitro assays and in vivo experiments in Apoe ^-/- mice.

Human lipidomics studies were performed on the 300OB cohort comprising 300 obese and overweight individuals at risk of cardiovascular disease. In vitro assays were carried out using human monocytes and macrophages, and in vivo experiments included histopathological, immunophenotyping and single-cell transcriptomic analyses.

In humans, we identified PS as an anti-inflammatory and atheroprotective biomarker. Hence, we developed a high-density lipoprotein (HDL)-like formulation enriched in PS to exploit its properties in a targeted fashion in mice. In vitro , this formulation potently inhibited inflammatory cytokine production on human myeloid cells. Our in-depth in vivo experiments provided evidence of the formulation's potent plaque-stabilizing and anti-inflammatory actions. These effects were mediated by a shift in the monocyte/macrophage compartment toward homeostatic/repairing phenotypes.

Collectively, our results demonstrate that HDL-associated PS potently suppresses inflammation and atheroprogression, and holds promise as a viable approach to improve immunomodulatory therapies.