scRNA-seq analysis of skin CD45+ cells mice where Tsc2 is deleted in CD11c-expressing cells. scRNA-seq analysis of skin CD45+ cells mice where Tsc2 is deleted in CD11c-expressing cells

Rationale: Chronic sarcoidosis is a complex granulomatous disease with limited treatment options that can progress over time. Understanding the molecular pathways contributing to disease would aid in new therapeutic development. Objectives: To understand if macrophages from non-resolving chronic sarcoidosis patients are predisposed to macrophage aggregation and granuloma formation, and if modulation of the underlying molecular pathways influence sarcoidosis granuloma formation. Methods: Macrophages were cultivated in vitro from isolated peripheral blood CD14+ monocytes and evaluated for spontaneous aggregation. Transcriptomics analyses, phenotypic and drug inhibitory experiments were performed on these monocyte-derived macrophages. Human skin biopsies from sarcoidosis patients and a myeloid Tsc2-specific sarcoidosis mouse model were analyzed for validatory experiments. Measurements and Main Results: Monocyte-derived macrophages from chronic sarcoidosis patients spontaneously formed extensive granulomas in vitro compared to healthy controls. Transcriptomic analyses separated healthy and sarcoidosis macrophages and identified an enrichment in lipid metabolic processes. In vitro patient granulomas, sarcoidosis mouse model granulomas, and those directly analyzed from lesional patient skin expressed an aberrant lipid metabolism profile and contained increased neutral lipids. Conversely, a combination of statins and cholesterol-reducing agents reduced granuloma formation both in vitro and in vivo in a sarcoidosis mouse model. Conclusions: Together, our findings show that altered lipid metabolism in sarcoidosis macrophages is associated with its predisposition to granuloma formation and suggest cholesterol-reducing therapies as a treatment option in patients. Overall design: Skin CD45+ immune cells

研究背景：慢性结节病是一种复杂的肉芽肿性疾病，治疗选择有限且可随病情进展。阐明参与疾病发生发展的分子通路，将有助于新型治疗手段的开发。
研究目的：明确非自愈性慢性结节病患者来源的巨噬细胞是否易于发生巨噬细胞聚集及肉芽肿形成，同时探究潜在分子通路的调控是否会影响结节病肉芽肿的形成。
研究方法：从分离得到的外周血CD14+单核细胞中体外培养巨噬细胞，并评估其自发聚集情况。对这些单核细胞来源的巨噬细胞开展转录组学分析、表型分析及药物抑制实验。同时，对结节病患者的皮肤活检样本以及髓系细胞特异性Tsc2缺陷结节病小鼠模型进行分析，以验证实验结果。
检测指标与主要结果：与健康对照相比，慢性结节病患者来源的单核细胞源性巨噬细胞可在体外自发形成大量肉芽肿。转录组学分析可区分健康与结节病巨噬细胞，并发现脂质代谢过程显著富集。体外培养的患者来源肉芽肿、结节病小鼠模型肉芽肿以及直接取自患者病变皮肤的肉芽肿均表现出异常脂质代谢特征，且中性脂质含量升高。反之，他汀类药物与降胆固醇药物联合使用，可在体外以及结节病小鼠模型体内均抑制肉芽肿形成。
研究结论：综上，本研究结果表明，结节病巨噬细胞的脂质代谢异常与其易形成肉芽肿的特性相关，并提示降胆固醇治疗可作为该类患者的潜在治疗选择。
整体实验设计：皮肤CD45+免疫细胞