Immune cells residing in white adipose tissue have been highlighted as important factors contributing to the pathogenesis of metabolic diseases, but the molecular regulators that drive adipose tissue immune cell remodeling during obesity remain largely unknown. Using index and transcriptional single-cell sorting, we comprehensively map all adipose tissue immune populations in both mice and humans during obesity. We describe a novel and conserved Trem2+ lipid-associated macrophage (LAM) subset and identify markers, spatial localization, and functional pathways associated with these cells. Genetic ablation of Trem2 in mice globally inhibits the downstream LAM molecular program during obesity, leading to adipocyte hypertrophy and both tissue-level and systemic hypercholesterolemia and glucose intolerance. These findings identify Trem2 signaling as a major pathway by which macrophages respond to loss of tissue-level lipid homeostasis, highlighting Trem2 as a key sensor of metabolic pathologies across multiple tissues and a potential therapeutic target in metabolic diseases. SOURCE: Ido Amit (ido.amit@weizmann.ac.il) -  Weizmann Institute of Science

Pluto Bioinformatics

GSE128518: Lipid-associated macrophages control metabolic homeostasis in a Trem2-dependent manner