Single-cell RNA sequencing reveals the induction of novel myeloid and myeloid-associated cell populations in visceral fat with long-term obesity

Macrophages and other immune cells are important contributors to obesity-associated inflammation; however, the cellular identities of these specific populations remain unknown. In this study, we identified individual populations of myeloid cells found in mouse epididymal/visceral adipose tissue by single-cell RNA sequencing, immunofluorescence, and flow cytometry. Multiple canonical correlation analysis identified 11 unique myeloid and myeloid-associate cell populations. In obese mice, we detected an increased percentage of monocyte-derived pro-inflammatory cells expressing CD9 and TREM-2, as well as significantly decreased percentages of multiple cell populations, including tissue-resident cells expressing LYVE1, Mafb, and CD206. We have identified and validated a novel myeloid/macrophage population defined by Ly6a expression, exhibiting both myeloid and mesenchymal characteristics, with both hematopoietic and pro-fibrotic markers. Our mouse adipose tissue myeloid cell atlas provides an important resource to target obesity-associated inflammation and fibrosis. single cell RNA seuqnecing of the CD45posCD11bpos myeloid cells from mouse visceral adipose tissue