Department of Microbiology, Immunology, and Molecular Genetics (S.K.S., A.M., Z.F., M.M., C.E., D.S., Z.Z., S.C., R.C.D., T.B.R., A.J.L.), University of California, Los Angeles.
Department of Medicine (S.K.S., A.M., Z.F., M.M., C.E., D.S., Z.Z., S.C., R.C.D., T.B.R., A.J.L.), University of California, Los Angeles.
Arterioscler Thromb Vasc Biol. 2021 Jan;41(1):220-233. doi: 10.1161/ATVBAHA.120.315255. Epub 2020 Oct 22.
Previous studies have shown that deficiency of M-CSF (macrophage colony-stimulating factor; or CSF1 [colony stimulating factor 1]) dramatically reduces atherosclerosis in hyperlipidemic mice. We characterize the underlying mechanism and investigate the relevant sources of CSF1 in lesions. Approach and Results: We quantitatively assessed the effects of CSF1 deficiency on macrophage proliferation and apoptosis in atherosclerotic lesions. Staining of aortic lesions with markers of proliferation, Ki-67 and bromodeoxyuridine, revealed around 40% reduction in CSF1 heterozygous (Csf1) as compared with WT (wild type; Csf1) mice. Similarly, staining with a marker of apoptosis, activated caspase-3, revealed a 3-fold increase in apoptotic cells in Csf1 mice. Next, we determined the cellular sources of CSF1 contributing to lesion development. Cell-specific deletions of Csf1 in smooth muscle cells using SM22α-Cre (smooth muscle protein 22-alpha-Cre) reduced lesions by about 40%, and in endothelial cells, deletions with Cdh5-Cre (VE-cadherin-Cre) reduced lesions by about 30%. Macrophage-specific deletion with LysM-Cre (lysozyme M-Cre), on the other hand, did not significantly reduce lesions size. Transplantation of Csf1 null (Csf1) mice bone marrow into Csf1 mice reduced lesions by about 35%, suggesting that CSF1 from hematopoietic cells other than macrophages contributes to atherosclerosis. None of the cell-specific knockouts affected circulating CSF1 levels, and only the smooth muscle cell deletions had any effect on the percentage monocytes in the circulation. Also, Csf1 mice did not exhibit significant differences in Ly6C/Ly6C monocytes as compared with Csf1.
CSF1 contributes to both macrophage proliferation and survival in lesions. Local CSF1 production by smooth muscle cell and endothelial cell rather than circulating CSF1 is the primary driver of macrophage expansion in atherosclerosis.
先前的研究表明，M-CSF（巨噬细胞集落刺激因子；或 CSF1 [集落刺激因子 1]）缺乏会显著减少高脂血症小鼠的动脉粥样硬化。我们描述了潜在的机制，并研究了病变中 CSF1 的相关来源。
我们定量评估了 CSF1 缺乏对动脉粥样硬化病变中巨噬细胞增殖和凋亡的影响。用增殖标志物 Ki-67 和溴脱氧尿苷对主动脉病变进行染色，结果显示与 WT（野生型；Csf1）小鼠相比，CSF1 杂合子（Csf1）小鼠的增殖减少了约 40%。同样，用凋亡标志物激活的 caspase-3 进行染色，发现 Csf1 小鼠的凋亡细胞增加了 3 倍。接下来，我们确定了导致病变发展的 CSF1 细胞来源。使用 SM22α-Cre（平滑肌蛋白 22-α-Cre）在平滑肌细胞中进行 CSF1 的细胞特异性缺失，可使病变减少约 40%，而使用 Cdh5-Cre（VE-钙粘蛋白-Cre）在血管内皮细胞中进行缺失可使病变减少约 30%。另一方面，用 LysM-Cre（溶菌酶 M-Cre）进行巨噬细胞特异性缺失，并未显著减少病变大小。将 Csf1 敲除（Csf1）小鼠的骨髓移植到 Csf1 小鼠中，可使病变减少约 35%，这表明除了巨噬细胞以外，来自造血细胞的 CSF1 有助于动脉粥样硬化。细胞特异性敲除均未影响循环 CSF1 水平，只有平滑肌细胞缺失对循环中单核细胞的百分比有任何影响。此外，与 Csf1 相比，Csf1 小鼠的 Ly6C/Ly6C 单核细胞也没有显著差异。
CSF1 有助于病变中巨噬细胞的增殖和存活。平滑肌细胞和内皮细胞产生的局部 CSF1 而不是循环 CSF1 是动脉粥样硬化中巨噬细胞扩张的主要驱动因素。
