library_construction_protocol: Aortas from Ldlr-/- and Ldlr-/-Trem2-/- mice fed a high fat diet for 10 weeks were snap frozen in liquid nitrogen and cryoconserved at -80°C. Nuclei from n=3 mice per group were isolated using Chromium Nuclei Isolation Kits (10x Genomics) according to the manufacturer's instruction. For counting, nuclei were labelled with DAPI and counted using a fluorescence microscope and a Neubauer counting chamber (concentration range: 1,400-2,300 nuclei/µl). Nuclei from each sample were loaded onto separate lanes of the 10x Genomics Chromium with the aim to recover 10,000 nuclei per sample, using loading volumes recommended by the manufacturer. We employed Chromium Next GEM Single Cell 3' Kit v3.1 (10x Genomics). Libraries were generated according to the manufacturer's instructions.  All libraries were quantified by QubitTM 3.0 Fluometer (ThermoFisher) and quality was checked using 2100 Bioanalyzer with High Sensitivity DNA kit (Agilent). Sequencing was performed using a S1 flowcell with Novaseq 6000 platform (Illumina) targeting 26,500 reads per nucleus. Single nuclei were encapsulated into droplets with the Chromium™ Controller (10x Genomics). Transcripts captured in all cells encapsulated with a bead were uniquely barcoded using a combination of a 16 bp 10x Barcode and a 12 bp unique molecular identifier (UMI). cDNA libraries were generated using the Chromium™ Single Cell 3' Library & Gel Bead Kit v3 (10x Genomics) following the detailed protocol provided by the manufacturer.