| Summary: | Oncostatin M (OSM) is a secreted cytokine mainly involved in chronic inflammatory and cardiovascular diseases through binding to OSM receptor β (OSMR-β). Recent studies demonstrated that the presence of OSM contributed to the destabilization of atherosclerotic plaque. To investigate whether OSMR-β deficiency affects atherosclerosis, male OSMR-β−/−ApoE−/− mice were generated and utilized. Here we observed that OSMR-β expression was remarkably upregulated in both human and mouse atherosclerotic lesions, which were mainly located in macrophages. We found that OSMR-β deficiency significantly ameliorated atherosclerotic burden in aorta and aortic root relative to ApoE-deficient littermates and enhanced the stability of atherosclerotic plaques by increasing collagen and smooth muscle cell content, while decreasing macrophage infiltration and lipid accumulation. Moreover, bone marrow transplantation of OSMR-β−/− hematopoietic cells to atherosclerosis-prone mice displayed a consistent phenotype. Additionally, we observed a relatively reduced level of JAK2 and signal transducer and activator of transcription (STAT)3 in vivo and under Ox-LDL stimulation in vitro. Our findings suggest that OSMR-β deficiency in macrophages improved high-fat diet-induced atherogenesis and plaque vulnerability. Mechanistically, the protective effect of OSMR-β deficiency on atherosclerosis may be partially attributed to the inhibition of the JAK2/STAT3 activation in macrophages, whereas OSM stimulation can activate the signaling pathway.
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