Peptidylarginine deiminase 4 deficiency in bone marrow cells prevents plaque progression without decreasing atherogenic inflammation in apolipoprotein E-knockout mice

These results suggest that pharmacological inhibition of PAD4 may impede lipid accumulation and lesion progression despite no beneficial effects on vascular inflammation.

Lethally irradiated ApoE -/- mice were reconstituted with ApoE -/-/Pad4 -/- bone marrow cells and fed a high-fat diet (HFD) for 4 and 10 weeks, respectively. PAD4 deficiency did not prevent the development of atherosclerotic lesions after 4 weeks of HFD. However, after 10 weeks of HFD, mice with bone marrow cells-restricted PAD4 deficiency displayed significantly reduced lesion size, impaired lipid incorporation, decreased necrotic core area and less collagen when compared to ApoE -/- bone marrow-transplanted mice as demonstrated by histological staining. Moreover, flow cytometric analysis and quantitative real-time PCR revealed different macrophage subsets in atherosclerotic lesions and higher inflammatory response in these mice, as reflected by increased content of M1-like macrophages and upregulated aortic expression of the pro-inflammatory genes CCL2 and iNOS. Notably, diminished oxLDL uptake by in vitro-polarized M1-like macrophages was evidenced when compared to M2-like cells.