Figure 1.

Overview of macrophages subsets in lean and obese adipose tissue and liver. Single-cell RNA sequencing has identified macrophage subpopulations that accumulate in liver and adipose tissue in the setting of obesity. These obese adipose tissue macrophages (ATMs) and NASH-associated macrophages (NAMs) are derived from infiltrating monocytes and display distinct surface markers (Trem2, CD9) and functions compared to resident tissue macrophages. In the liver, loss of resident KCs in NASH induces the appearance of monocyte-derived KCs (mo-KCs), which likely fill the empty KC niche and may exert similar functions to resident KCs.