Myeloid cell interleukin-10 is essential for atherosclerosis protection in Apoe−/− mice

Atherosclerosis, the disease underlying stroke, myocardial infarction and ischemic heart failure, is initiated by the subendothelial retention of lipoproteins and cholesterol, which then triggers a non-resolving inflammatory process driving plaque progression in the artery wall. Myeloid cells and in particular macrophages are the primary driver of this process. IL10 is a prototypic anti-inflammatory cytokine made by several immune cells such as macrophages. IL10 is also essential for the protection against atherosclerosis. However, it is not known which cells are responsible for the IL10 production mediating protection from atherosclerosis. Here, we crossed the VertX mouse model, in which an IRES-enhanced green fluorescent protein (eGFP) fusion protein was placed downstream of exon 5 of the IL-10 gene, to the atherosclerosis-prone Apoe−/− background. We found that myeloid cells express high levels of IL10 GFP in VertX-Apoe−/− mice. By scRNAseq we found that macrophages especially inflammatory macrophages in plaques are the main producers of IL10 in atherosclerosis. To address whether IL10 secreted by myeloid cells is essential for the protection, we developed a LyzMCreIL-10flox/flox mouse crossed in the Apoe−/− background and confirmed that macrophages were unable to secrete IL-10. We discovered that the LyzMCreIL-10flox/floxApoe−/− mice developed significantly more atherosclerosis than LyzMCreIL-10+/+Apoe−/−, both on chow and lipid-rich diet. Flow cytometry data and cytokine measurements suggest that the depletion of IL-10 in myeloid cells increases Th17 cells with elevated IL-17a, IL-17f and CCL20 in blood plasma. These data underscore the critical roles of macrophage-derived IL-10 in limiting atherosclerosis. Supported by grants NIH HL 115232, 145241, and HL088093.