Human adipocyte and adipose tissue-derived extracellular vesicles induced a pro-inflammatory macrophage phenotype that interfered with insulin signaling in adipocytes.
Human adipocyte-derived extracellular vesicles mediate a pro-inflammatory loop between adipocytes and macrophages that may aggravate local and systemic insulin resistance.
OBJECTIVE: Extracellular vesicles (EVs) released by human adipocytes or adipose tissue (AT)-explants play a role in the paracrine interaction between adipocytes and macrophages, a key mechanism in AT inflammation, leading to metabolic complications like insulin resistance (IR) were determined. METHODS: EVs released from in vitro differentiated adipocytes and AT-explants ex vivo were characterized by electron microscopy, Western blot, multiplex adipokine-profiling, and quantified by flow cytometry. Primary monocytes were stimulated with EVs from adipocytes, subcutaneous (SCAT) or omental-derived AT (OAT), and phenotyped. Macrophage supernatant was subsequently used to assess the effect on insulin signaling in adipocytes. RESULTS: Adipocyte and AT-derived EVs differentiated monocytes into macrophages characteristic of human adipose tissue macrophages (ATM), defined by release of both pro- and anti-inflammatory cytokines. The adiponectin-positive subset of AT-derived EVs, presumably representing adipocyte-derived EVs, induced a more pronounced ATM-phenotype than the adiponectin-negative AT-EVs. This effect was more evident for OAT-EVs versus SCAT-EVs. Furthermore, supernatant of macrophages pre-stimulated with AT-EVs interfered with insulin signaling in human adipocytes. Finally, the number of OAT-derived EVs correlated positively with patients HOMA-IR. CONCLUSIONS: A possible role for human AT-EVs in a reciprocal pro-inflammatory loop between adipocytes and macrophages, with the potential to aggravate local and systemic IR was demonstrated.
Kranendonk et al. (Thu,) conducted a other in Adipose tissue inflammation and insulin resistance. Extracellular vesicles (EVs) from adipocytes and adipose tissue was evaluated on Macrophage differentiation and insulin signaling interference. Human adipocyte and adipose tissue-derived extracellular vesicles induced a pro-inflammatory macrophage phenotype that interfered with insulin signaling in adipocytes.