Table_2_Myeloid cell ACE shapes cellular metabolism and function in PCSK-9 induced atherosclerosis.xlsx

The pathogenesis of atherosclerosis is defined by impaired lipid handling by macrophages which increases intracellular lipid accumulation. This dysregulation of macrophages triggers the accumulation of apoptotic cells and chronic inflammation which contributes to disease progression. We previously reported that mice with increased macrophage-specific angiotensin-converting enzyme, termed ACE10/10 mice, resist atherosclerosis in an adeno-associated virus-proprotein convertase subtilisin/kexin type 9 (AAV-PCSK9)-induced model. This is due to increased lipid metabolism by macrophages which contributes to plaque resolution. However, the importance of ACE in peripheral blood monocytes, which are the primary precursors of lesional-infiltrating macrophages, is still unknown in atherosclerosis. Here, we show that the ACE-mediated metabolic phenotype is already triggered in peripheral blood circulating monocytes and that this functional modification is directly transferred to differentiated macrophages in ACE10/10 mice. We found that Ly-6Clo monocytes were increased in atherosclerotic ACE10/10 mice. The monocytes isolated from atherosclerotic ACE10/10 mice showed enhanced lipid metabolism, elevated mitochondrial activity, and increased adenosine triphosphate (ATP) levels which implies that ACE overexpression is already altered in atherosclerosis. Furthermore, we observed increased oxygen consumption (VO2), respiratory exchange ratio (RER), and spontaneous physical activity in ACE10/10 mice compared to WT mice in atherosclerotic conditions, indicating enhanced systemic energy consumption. Thus, ACE overexpression in myeloid lineage cells modifies the metabolic function of peripheral blood circulating monocytes which differentiate to macrophages and protect against atherosclerotic lesion progression due to better lipid metabolism.

动脉粥样硬化（atherosclerosis）的发病机制以巨噬细胞（macrophages）脂质处理功能受损为特征，该损伤会加剧细胞内脂质蓄积（intracellular lipid accumulation）。巨噬细胞的这种功能失调会触发凋亡细胞（apoptotic cells）积累与慢性炎症（chronic inflammation），进而推动疾病进展。我们此前的研究报道称，巨噬细胞特异性血管紧张素转换酶（angiotensin-converting enzyme，ACE）过表达的小鼠（命名为ACE10/10小鼠），在腺相关病毒-前蛋白转化酶枯草杆菌蛋白酶/kexin 9型（adeno-associated virus-proprotein convertase subtilisin/kexin type 9，AAV-PCSK9）诱导的动脉粥样硬化模型中表现出疾病抵抗性，这源于巨噬细胞脂质代谢能力增强，有助于粥样斑块消退。然而，作为病灶浸润巨噬细胞（lesional-infiltrating macrophages）主要前体的外周血单核细胞（peripheral blood monocytes）中，ACE在动脉粥样硬化中的作用仍未明确。本研究证实，ACE介导的代谢表型（metabolic phenotype）在外周血循环单核细胞中即已被激活，且这种功能修饰可直接传递至ACE10/10小鼠体内分化而来的巨噬细胞。我们发现，动脉粥样硬化ACE10/10小鼠体内Ly-6Clo单核细胞数量增加。从动脉粥样硬化ACE10/10小鼠中分离得到的单核细胞，其脂质代谢能力增强、线粒体活性（mitochondrial activity）升高且三磷酸腺苷（adenosine triphosphate，ATP）水平上升，这表明动脉粥样硬化状态下ACE过表达已发生改变。此外，在动脉粥样硬化造模条件下，与野生型（WT）小鼠相比，ACE10/10小鼠的耗氧量（oxygen consumption，VO2）、呼吸交换率（respiratory exchange ratio，RER）与自发活动（spontaneous physical activity）均有所提升，提示全身能量消耗增强。综上，髓系细胞（myeloid lineage cells）中ACE过表达可改变外周血循环单核细胞的代谢功能，使其分化为巨噬细胞后，凭借更优异的脂质代谢能力延缓动脉粥样硬化病灶进展。