Leukemia inhibitory factor receptor inhibition by EC359 reduces atherosclerotic stenosis grade in Ldlr^-/- mice

Cytokines are involved in all stages of atherosclerosis, generally contributing to disease progression. Previously, members of the Interleukin (IL)-6 cytokine family, such as IL-6, oncostatin M, and cardiotrophin-1, have been extensively studied in atherosclerosis. However, the role of leukemia inhibitory factor (LIF), member of the IL-6 family, and its receptor (LIFR), remains to be further elucidated. Therefore, the aim of this study is to provide insight in LIF receptor signalling in atherosclerosis development. Single-cell RNA sequencing analysis of human carotid artery plaques revealed that mast cells highly express LIF, whereas LIFR was specifically expressed on activated endothelial cells. A similar expression pattern of Lifr was observed in mouse atherosclerotic plaques. Next, female Western-type diet fed Ldlr^-/- mice were treated with LIF receptor inhibitor EC359 (5 mg/kg s.c., n = 15) or control solvent (n = 15) three times per week for eight weeks. Stenosis grade was reduced in the aortic root of EC359 treated mice compared to control mice, but treatment did not affect plaque composition. Serum cholesterol levels were significantly reduced in EC359 treated mice, likely attributed to a reduction in VLDL cholesterol levels. Furthermore, LIF receptor inhibition reduced Pecam1 and Vcam1 expression in the aorta. Consequently, immune cell infiltration was reduced in aortic plaques of EC359 treated mice compared to control mice. Conclusively, we demonstrated that LIF receptor is a potential therapeutic target in atherosclerosis by reducing plaque size, attributed to lower serum cholesterol levels, reduced endothelial activation and less immune cell infiltration in the plaque.