Department of Regeneration in Hematopoiesis, Institute for Immunology, TU Dresden, Germany (E.C.).
Immunology of Aging, Leibniz Institute on Aging-Fritz Lipmann Institute, Jena, Germany (E.C.).
Arterioscler Thromb Vasc Biol. 2023 Jun;43(6):889-906. doi: 10.1161/ATVBAHA.123.318956. Epub 2023 Mar 9.
Peripheral ischemia caused by peripheral artery disease is associated with systemic inflammation, which may aggravate underlying comorbidities such as atherosclerosis and heart failure. However, the mechanisms of increased inflammation and inflammatory cell production in patients with peripheral artery disease remain poorly understood.
We used peripheral blood collected from patients with peripheral artery disease and performed hind limb ischemia (HI) in mice fed a Western diet and C57BL/6J mice with a standard laboratory diet. Bulk and single-cell RNA sequencing analysis, whole-mount microscopy, and flow cytometry were performed to analyze hematopoietic stem and progenitor cell (HSPC) proliferation, differentiation, and relocation.
We observed augmented numbers of leukocytes in the blood of patients with peripheral artery disease and mice with HI. RNA sequencing and whole-mount imaging of the bone marrow revealed HSPC migration into the vascular niche from the osteoblastic niche and their exaggerated proliferation and differentiation. Single-cell RNA sequencing demonstrated alterations in the genes responsible for inflammation, myeloid cell mobilization, and HSPC differentiation after HI. Heightened inflammation in mice after HI aggravated atherosclerosis. Surprisingly, bone marrow HSPCs expressed higher amounts of the receptors for IL (interleukin)-1 and IL-3 after HI. Concomitantly, the promoters of and had augmented H3K4me3 and H3K27ac marks after HI. Genetic and pharmacological inhibition of these receptors resulted in suppressed HSPC proliferation, reduced leukocyte production, and ameliorated atherosclerosis.
Our findings demonstrate increased inflammation, HSPC abundance in the vascular niches of the bone marrow, and elevated IL-3Rb and IL-1R1 (IL-1 receptor 1) expression in HSPC following HI. Furthermore, the IL-3Rb and IL-1R1 signaling plays a pivotal role in HSPC proliferation, leukocyte abundance, and atherosclerosis aggravation after HI.
外周动脉疾病引起的外周局部缺血与全身炎症有关，这可能会加重动脉粥样硬化和心力衰竭等潜在合并症。然而，外周动脉疾病患者炎症和炎症细胞产生增加的机制仍知之甚少。
我们使用外周血样本来自外周动脉疾病患者，并在接受西方饮食的小鼠和接受标准实验室饮食的 C57BL/6J 小鼠中进行后肢缺血（HI）。进行了批量和单细胞 RNA 测序分析、全 mounting 显微镜和流式细胞术，以分析造血干细胞和祖细胞（HSPC）的增殖、分化和重定位。
我们观察到外周动脉疾病患者和 HI 小鼠的血液中白细胞数量增加。骨髓的 RNA 测序和全 mounting 成像显示 HSPC 从成骨细胞巢迁移到血管巢，并表现出过度增殖和分化。单细胞 RNA 测序显示 HI 后负责炎症、髓样细胞动员和 HSPC 分化的基因发生改变。HI 后小鼠的炎症加剧动脉粥样硬化。令人惊讶的是，HI 后骨髓 HSPC 表达更高水平的 IL（白细胞介素）-1 和 IL-3 受体。同时，HI 后和基因的启动子具有更多的 H3K4me3 和 H3K27ac 标记。这些受体的遗传和药理学抑制导致 HSPC 增殖减少、白细胞产生减少和动脉粥样硬化改善。
我们的研究结果表明，HI 后骨髓血管巢中炎症增加、HSPC 丰度增加以及 HSPC 中 IL-3Rb 和 IL-1R1（IL-1 受体 1）表达升高。此外，IL-3Rb 和 IL-1R1 信号在 HI 后 HSPC 增殖、白细胞丰度和动脉粥样硬化加重中发挥关键作用。
