Vegting Yosta, Jongejan Aldo, Neele Annette E, Claessen Nike, Sela Gal, Prange Koen H M, Kers Jesper, Roelofs Joris J T H, van der Heijden Joost W, de Boer Onno J, Remmerswaal Ester B M, Vogt Liffert, Bemelman Frederike J, de Winther Menno P J, Moerland Perry D, Hilhorst Marc L
Amsterdam UMC location University of Amsterdam, Department of Internal Medicine, section of Nephrology, Amsterdam, The Netherlands.
Amsterdam Institute for Infection and Immunity, Inflammatory diseases, Amsterdam, The Netherlands.
Nephrol Dial Transplant. 2024 Dec 18. doi: 10.1093/ndt/gfae292.
Kidney macrophage infiltration is a histological hallmark of vasculitic lesions and is strongly linked to disease activity in anti-neutrophil cytoplasmic antibodies (ANCA)-associated glomerulonephritis (AGN). The precise mechanisms by which kidney macrophages influence local inflammation and long-term damage remain largely unknown.
Here, we investigate kidney macrophage diversity using single-cell transcriptome analysis of 25 485 freshly retrieved unfrozen, high-quality kidney CD45+ immune cells from five AGN patients during active disease, a lupus nephritis and nephrectomy control. Detailed subclustering of myeloid cells was performed to identify disease-specific macrophage subtypes. Next, transcriptome differences between macrophage subsets and disease serotypes were assessed. Findings were validated by immunostainings of an extended cohort of kidney biopsies and flow cytometric analysis of peripheral blood monocytes.
Four main macrophage subsets were identified, including a classical monocyte-derived macrophage (MDM) subset expressing a chemotactic (CXCL2, CXCL3, CXCL8, CCL3) and pro-inflammatory (IL1β, TNF) set of markers and a osteopontin/SPP1+ lipid-associated macrophage (SPP1 LAMs) subtype exhibiting distinctive upregulation of fibrotic genesets. AGN samples revealed a markedly increased proportion of CD163+ macrophages, predominantly composed of classical MDMs, accompanied by resident-like C1Q macrophages, and SPP1 LAMs An analogous trend was observed in the expansion of peripheral blood classical monocytes during active disease. The proteinase 3 (PR3)-AGN subtype exhibited heightened classical MDM and SPP1 LAM infiltration and markers of acute inflammation, while interferon signaling and markers of chronicity were reduced compared to myeloperoxidase (MPO)-AGN.
Our findings highlight the expression of inflammatory and fibrotic genes by kidney macrophage subsets in AGN. Classical monocyte dysregulation might contribute to inflammation in the pathogenesis of AGN. Targeting these specific monocyte/macrophage subsets may potentially control the inflammatory cascade and attenuate resulting fibrosis in AGN and kidney disease in general.
肾脏巨噬细胞浸润是血管炎性病变的组织学特征，并且与抗中性粒细胞胞浆抗体（ANCA）相关肾小球肾炎（AGN）的疾病活动密切相关。肾脏巨噬细胞影响局部炎症和长期损伤的确切机制在很大程度上仍不清楚。
在此，我们通过对5例处于疾病活动期的AGN患者、1例狼疮性肾炎患者及1例肾切除对照患者新鲜获取的25485个未冷冻、高质量的肾脏CD45+免疫细胞进行单细胞转录组分析，来研究肾脏巨噬细胞的多样性。对髓系细胞进行详细的亚聚类分析以鉴定疾病特异性巨噬细胞亚型。接下来，评估巨噬细胞亚群与疾病血清型之间的转录组差异。通过对更大队列的肾脏活检组织进行免疫染色以及对外周血单核细胞进行流式细胞术分析来验证研究结果。
鉴定出了四个主要的巨噬细胞亚群，包括一个表达趋化因子（CXCL2、CXCL3、CXCL8、CCL3）和促炎因子（IL1β、TNF）标志物的经典单核细胞衍生巨噬细胞（MDM）亚群，以及一个骨桥蛋白/SPP1+脂质相关巨噬细胞（SPP1 LAMs）亚型，该亚型表现出纤维化基因集的独特上调。AGN样本显示CD163+巨噬细胞比例显著增加，主要由经典MDM组成，同时伴有驻留样C1Q巨噬细胞和SPP1 LAMs。在疾病活动期，外周血经典单核细胞的扩增也观察到类似趋势。蛋白酶3（PR3）-AGN亚型表现出经典MDM和SPP1 LAM浸润增加以及急性炎症标志物升高，而与髓过氧化物酶（MPO）-AGN相比，干扰素信号和慢性炎症标志物减少。
我们的研究结果突出了AGN中肾脏巨噬细胞亚群炎症和纤维化基因的表达。经典单核细胞失调可能在AGN发病机制中导致炎症。靶向这些特定的单核细胞/巨噬细胞亚群可能潜在地控制炎症级联反应，并减轻AGN及一般肾脏疾病中由此产生的纤维化。
