Immunolipidomics reveals a globoside network during the resolution of pro-inflammatory response in human macrophages

Toll-like receptor 4 (TLR4)-mediated changes in macrophages reshape intracellular lipid pools to coordinate an effective innate immune response. Although this has been previously well-studied in different model systems, it remains incompletely understood in primary human macrophages. Here we report time-dependent lipidomic and transcriptomic responses to lipopolysaccharide (LPS) in primary human macrophages from healthy donors. We grouped the variation of ~200 individual lipid species measured by LC-MS/MS into eight temporal clusters. Among all other lipids, glycosphingolipids (glycoSP) and cholesteryl esters (CE) showed a sharp increase during the resolution phase (between 8h or 16h post LPS). GlycoSP, belonging to the globoside family (Gb3 and Gb4), showed the greatest inter-individual variability among all lipids quantified. Integrative network analysis between GlycoSP/CE levels and genome-wide transcripts, identified Gb4 d18:1/16:0 and CE 20:4 association with subnetworks enriched for T cell receptor signaling (PDCD1, CD86, PTPRC, CD247, IFNG) and DC-SIGN signaling (RAF1, CD209), respectively. Our findings reveal Gb3 and Gb4 globosides as sphingolipids associated with the resolution phase of inflammatory response in human macrophages.

Toll样受体4（Toll-like receptor 4, TLR4）介导的巨噬细胞改变，可重塑细胞内脂质池，以协调有效的固有免疫应答。尽管此前已在多种模型系统中对该过程开展了充分研究，但在原代人巨噬细胞中，其机制仍未完全阐明。本研究针对健康捐赠者来源的原代人巨噬细胞，报道了其在脂多糖（lipopolysaccharide, LPS）刺激下的时间依赖性脂质组学与转录组学应答。我们将液相色谱-串联质谱（LC-MS/MS）检测到的约200种单个脂质物种的变化分为8个时间簇。在所有检测到的脂质中，糖鞘脂（glycosphingolipids, glycoSP）与胆固醇酯（cholesteryl esters, CE）在炎症消退阶段（LPS刺激后8小时至16小时期间）呈现显著上调。属于球苷脂家族（globoside）的Gb3与Gb4型糖鞘脂，在所有定量脂质中个体间差异最为显著。通过整合糖鞘脂/胆固醇酯水平与全基因组转录本的网络分析，本研究发现Gb4 d18:1/16:0与CE 20:4分别与富集T细胞受体信号通路（PDCD1、CD86、PTPRC、CD247、IFNG）以及DC-SIGN信号通路（RAF1、CD209）的子网存在关联。本研究结果表明，Gb3与Gb4型球苷脂作为鞘脂类，与人巨噬细胞炎症应答的消退阶段密切相关。