A Peptide Analogue of Selectin Ligands Attenuated Atherosclerosis by Inhibiting Monocyte Activation

Abstract EN

Background.

Circulating monocytes play a critical role in the pathogenesis of atherosclerosis.

Monocyte homing to sites of atherosclerosis is primarily initiated by selectin.

Thus, blockade of the interaction of selectins and their ligands holds a significant role in monocyte homing which might be a potential approach to treat atherosclerosis.

Here, we investigated the efficacy of a novel peptide analogue of selectin ligands IELLQAR in atherosclerosis.

Methods and Results.

In this study, we firstly measured the effect of the IELLQAR selectin-binding peptide on the inhibition of binding of selectins to monocytes by flow cytometry, which exhibited a dose-dependent inhibitory effect on the binding of the P-, E-, and L-selectins to monocytes, especially the inhibition of P-selectin binding to human peripheral blood monocytes (PBMCs) (half maximal inhibitory concentration (IC50~5 μM)) and THP-1 cells (IC50~10 μM).

Furthermore, IELLQAR inhibited P-selectin-induced activation of CD11b on the surface of monocytes and decreased adhesion of monocytes to the endothelium.

ApoE-/- mice with or without IELLQAR (1 or 3 mg/kg) fed a Western-type diet (WTD) or which had disturbed blood flow-induced shear stress underwent partial left carotid artery ligation (PLCA) to induce atherosclerosis.

In the WTD- and PLCA-induced atherosclerosis models, atherosclerotic plaque formation and monocyte/macrophage infiltration of the arterial wall both decreased in ApoE-/- mice treated with the IELLQAR peptide.

Our results also revealed that IELLQAR inhibited the differentiation of monocytes into macrophages through P-selectin-dependent activation of the nuclear factor- (NF-) κB and mammalian target of rapamycin (mTOR) pathways.

Conclusion.

Collectively, our results demonstrated that IELLQAR, a peptide analogue of selectin ligands, inhibited selectin binding to monocytes, which led to subsequent attenuation of atherosclerosis via inhibition of monocyte activation.

Hence, use of the IELLQAR peptide provides a new approach and represents a promising candidate for the treatment of atherosclerosis in the early stage of disease.