Adipose Tissue Extracellular Vesicles Influence Interleukin-10 Secretion by Regulatory T Cells In Vitro

Obesity is characterized by chronic inflammation of adipose tissue, which is associated with the development of concomitant diseases. Recent studies indicate that regulatory T cells (Tregs) may play an important role in the pathogenesis of insulin resistance and type 2 diabetes mellitus (T2DM). The aim of the study was to evaluate the effect of extracellular vesicles (EVs) secreted by visceral and subcutaneous adipose tissue (VAT and SAT) of obese patients with/without T2DM on the Treg population, including their secretion of interleukin-10. EVs were obtained after cultivation of VAT and SAT of obese patients with/without T2DM and non-obese individuals. Primary culture of CD4+CD25+ Tregs was obtained by differentiating naive peripheral blood CD4+ T cells of healthy donors. Real-time PCR was used to assess the mRNA level of the genes of interest, and ELISA was used to determine the concentration of interleukin-10 in the culture medium. Simultaneous increase in the IL10 gene mRNA level and decrease in interleukin-10 secretion by Tregs were demonstrated after cultivation in the presence of VAT EVs; in the presence of SAT EVs from obese patients, the level of interleukin-10 secretion was slightly increased. The expression level of IL10 gene in SAT of non-obese individuals was lower compared to VAT, however, in obese patients with T2DM it was increased and comparable to that in VAT. AT EVs can potentially influence the population of Tregs, changing their suppressive activity and secretion of interleukin-10.