Identification of Fcmr-dependent heterogeneity in tumor associated mononuclear phagocytes

The mononuclear phagocytic system (MPS) is characterized by functional diversity and plasticity, including within the tumor microenvironment (TME). Tumor-associated mononuclear phagocytes (TMPs) within the TME come from various ontological origins. To determine how Fcmr deficiency might impact the functional heterogeneity of mature mononuclear phagocytes (MPs) within the TME, we performed single-cell RNA sequencing (scRNAseq) on MPs isolated from B16 tumors resected from Fcmr-/- and Fcmr+/+ mice. To evaluate a homogenous population of MPs within the TME we chose to examine cells harboring expression of markers found in more mature, differentiated MPs. Therefore, we then sorted MerTk+ CD64+ TMPs by FACS and subjected these cells to single-cell transcriptomic analyses using the Chromium 10X Genomics platform. We obtained RNAseq profiles from 6352 Fcmr+/+ and 7999 Fcmr-/- TMPs. Comparison of tumor mononuclear phagocytes from Fcmr+/+ and Fcmr-/- mice