Cellular basis of omentum activation and expansion revealed by single-cell RNA sequencing using a parabiosis model

Abstract

Although the physiological function of the omentum remains elusive, it has been proposed that it plays an important role in fat storage, immune regulation, and regeneration of injured tissues and organs. Although the omentum undergoes expansion upon activation, reports on the accurate assessment of increased cell types and the origin of the increased cells remain limited. To investigate this aspect, the omenta of parabiotic mice were subjected to activation using distinct fluorescent markers and single-cell RNA sequencing (scRNA-seq) was performed to identify circulation-derived omental cells. We found that a considerable number of circulating cells contributed to the activation of the omentum. The omental cells derived from circulating cells exhibited morphological features similar to those of fibroblasts. scRNA-seq revealed the existence of a novel cell population that co-expressed macrophage and fibroblast markers in the activated omentum, suggesting that it corresponded to circulating macrophage-derived fibroblast-like cells. Lineage tracing experiments revealed that most fibroblasts in the activated omentum were not derived from WT1-positive mesenchymal progenitors. The cell cluster also expressed various chemokine genes, indicating its role in the activation and recruitment of immune cells. These results provide important information regarding the activation of the omentum.

Cell origin and niche availability dictate the capacity of peritoneal macrophages to colonize the cavity and omentum

“…In line with recent publications [36,37] we demonstrate that the murine omentum contains a population of CD102 + macrophages that, like those in the cavity [4,21], are CSF1R + and rely on CSF1R signalling for survival. By virtue of their expression of peritoneal macrophage‐associated transcription factor GATA6 [6], we demonstrate CD102 + omental macrophages to be associated with omental FALCS.…”

Proteomic Characterization of Peritoneal Extracellular Vesicles in a Mouse Model of Peritoneal Fibrosis

“…Subsequently, data was clustered with the alignment methods in the Seurat package and performed with uniform manifold approximation and projection (UMAP). The final scRNA-seq data contained 7017 cells, which were annotated into seven main cell types of omentum according to methods of the two source articles. , Marker genes between different cell types were found using the Seurat function FindAllMarkers in a criteria that log-fold change > 0.25, Bonferroni-adjusted P -value < 0.05, and minimum percent of gene expression level in either cell type > 30%.…”