Distinct functional properties of murine perinatal and adult adipose progenitor subpopulations

A human omentum-specific mesothelial-like stromal population inhibits adipogenesis through IGFBP2 secretion

“…A striking example are the mesothelial cells that are almost exclusive to OM AT (Figures 2A, D, 3D). While the presence of mesothelial cells within the OM SVF has been reported previously 8,13,15,16 , their role within the adipose stem cell niche remained elusive. Our functional characterization revealed that these mesothelial cells can inhibit the differentiation of OM hASPCs (Figure 5D-E), suggesting that the mesothelium surrounding the OM AT could have a regulatory impact on its plasticity.…”

“…Our identification of an OM-specific anti-adipogenic cell lines evokes the discovery in mice of Aregs, which are stromal populations that negatively regulate the adipogenic capacity of ASPCs in mouse subcutaneous ATs, both by our 12,17 and other labs 16,18 . These discoveries suggest that, also in humans, AT plasticity may be orchestrated by distinct cues including not only endocrine signals but also specialized niche cells.…”

“…It may therefore prove difficult to find an equivalent population in mice. However, a very recent study by Zhang et al 16 of mouse epididymal AT did identify "mesothelial-like cells'' that shared markers with both mesothelial and mesenchymal cells and that were also defined by high Igfbp2 expression. This suggests that OM IGFBP2+ cells may be cellularly and functionally conserved between mouse and human, which in turn may open new experimental avenues to study their relevance in mediating OM AT plasticity in distinct metabolic contexts.…”

“…Hence, similarities and/or differences in hASPC composition beyond the SC and OM depots remain elusive. Studies in mice confirmed that ASPCs are highly heterogeneous across depots, but can be classified into three major overarching ASPC subpopulations 8,9,[11][12][13][14][15][16][17][18] . These subpopulations, characterized by the expression of specific cell surface markers, exhibit different functional properties 11 .…”

“…In contrast, Icam1+ (or Aoc3+) cells can be classified as pre-adipocytes (PreAs), showing a lower proliferation capacity and a more committed adipogenic state compared with ASCs. Finally, a subset of cells characterized by high expression of F3 were termed adipogenesis-regulatory cells (Aregs) due to their ability to regulate the differentiation capacity of other ASPCs [7][8][9][11][12][13][14][15][16][17][18] . A similar level of phenotypic characterization of hASPC populations is however still lacking, likely reflecting the challenge of having access to and/or gathering enough human biopsy material.…”