BACKGROUND:Systemic sclerosis (SSc) is a connective tissue disease that can serve as a model to study vascular changes in response to inflammation, autoimmunity, and fibrotic remodeling. Although microvascular changes are the earliest histopathologic manifestation of SSc, the vascular pathophysiology remains poorly understood.METHODS:We applied spatial proteomic approaches to deconvolute the heterogeneity of vascular cells at the single-cell level in situ and characterize cellular alterations of the vascular niches of patients with SSc. Skin biopsies of patients with SSc and control individuals were analyzed by imaging mass cytometry, yielding a total of 90 755 cells including 2987 endothelial cells and 4096 immune cells.RESULTS:We identified 7 different subpopulations of blood vascular endothelial cells (VECs), 2 subpopulations of lymphatic endothelial cells, and 3 subpopulations of pericytes. A novel population of CD34⁺;αSMA⁺ (α-smooth muscle actin);CD31⁺ VECs was more common in SSc, whereas endothelial precursor cells were decreased. Co-detection by indexing and tyramide signal amplification confirmed these findings. The microenvironment of CD34⁺;αSMA⁺;CD31⁺ VECs was enriched for immune cells and myofibroblasts, and CD34⁺;αSMA⁺;CD31⁺ VECs expressed markers of endothelial-to-mesenchymal transition. The density of CD34⁺;αSMA⁺;CD31⁺ VECs was associated with clinical progression of fibrosis in SSc.CONCLUSIONS:Using spatial proteomics, we unraveled the heterogeneity of vascular cells in control individuals and patients with SSc. We identified CD34⁺;αSMA⁺;CD31⁺ VECs as a novel endothelial cell population that is increased in patients with SSc, expresses markers for endothelial-to-mesenchymal transition, and is located in close proximity to immune cells and myofibroblasts. CD34⁺;αSMA⁺;CD31⁺ VEC counts were associated with clinical outcomes of progressive fibrotic remodeling, thus providing a novel cellular correlate for the crosstalk of vasculopathy and fibrosis.

中文翻译：

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空间蛋白质组学表征系统性硬化症中的血管生态位

背景：系统性硬化症（SSc）是一种结缔组织疾病，可以作为研究血管对炎症、自身免疫和纤维化重塑的反应变化的模型。尽管微血管变化是 SSc 最早的组织病理学表现，但血管病理生理学仍然知之甚少。 方法：我们应用空间蛋白质组学方法在单细胞水平原位解算血管细胞的异质性，并表征患者血管生态位的细胞改变与SSc。通过成像质谱流式细胞术对 SSc 患者和对照个体的皮肤活检进行分析，总共产生 90 755 个细胞，其中包括 2987 个内皮细胞和 4096 个免疫细胞。 结果：我们鉴定了 7 个不同的血管内皮细胞 (VEC) 亚群，其中 2 个亚群淋巴管内皮细胞和 3 个周细胞亚群。 CD34 ⁺；αSMA ⁺（α-平滑肌肌动蛋白）；CD31 ⁺ VEC的新群体在 SSc 中更为常见，而内皮前体细胞则减少。通过索引和酪酰胺信号放大的联合检测证实了这些发现。 CD34 ⁺ ;αSMA ⁺ ;CD31 ⁺ VEC的微环境富含免疫细胞和肌成纤维细胞，并且 CD34 ⁺ ;αSMA ⁺ ;CD31 ⁺ VEC 表达内皮向间质转化的标志物。 CD34 ⁺ ;αSMA ⁺ ;CD31 ⁺ VEC的密度与 SSc 纤维化的临床进展相关。结论：利用空间蛋白质组学，我们揭示了对照个体和 SSc 患者血管细胞的异质性。我们将 CD34 ⁺ ;αSMA ⁺ ;CD31 ⁺ VEC 确定为一种新型内皮细胞群，该细胞群在 SSc 患者中增加，表达内皮间质转化标记物，并且位于免疫细胞和肌成纤维细胞附近。 CD34 ⁺ ;αSMA ⁺ ;CD31 ⁺ VEC 计数与进行性纤维化重塑的临床结果相关，从而为血管病变和纤维化的串扰提供了新的细胞相关性。