Adipose-derived Mesenchymal Stromal Cells Modulate Lipid Metabolism and Lipid Droplet Biogenesis via AKT/mTOR -PPARγ Signalling in Macrophages

Sci Rep. 2019 Dec 30;9(1):20304. doi: 10.1038/s41598-019-56835-8.

Abstract

Mesenchymal stromal cells (MSCs) are a potential therapy for many chronic inflammatory diseases due to their regenerative, immunologic and anti-inflammatory properties. The two-way dialogue between MSCs and macrophages is crucial to tissue regeneration and repair. Previous research demonstrated that murine adipose-derived MSC conditioned medium (ASCcm) reprograms macrophages to an M2-like phenotype which protects from experimental colitis and sepsis. Here, our focus was to determine the molecular mechanism of lipid droplet biogenesis in macrophages re-educated using ASCcm. Adipose-derived MSC conditioned medium promotes phosphorylation of AKT/mTOR pathway proteins in macrophages. Furthermore, increased expression of PPARγ, lipid droplet biogenesis and PGE2 synthesis were observed in M2-like phenotype macrophages (high expression of arginase 1 and elevated IL-10). Treatment with mTOR inhibitor rapamycin or PPARγ inhibitor GW9662 suppressed lipid droplets and PGE2 secretion. However, these inhibitors had no effect on arginase-1 expression. Rapamycin, but not GW9662, inhibit IL-10 secretion. In conclusion, we demonstrate major effects of ASCcm to reprogram macrophage immunometabolism through mTOR and PPARγ dependent and independent pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / cytology*
  • Cell Communication*
  • Lipid Droplets / metabolism*
  • Lipid Metabolism*
  • Macrophages / metabolism*
  • Mesenchymal Stem Cells / metabolism*
  • Models, Biological
  • PPAR gamma / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism
  • Signal Transduction*
  • TOR Serine-Threonine Kinases / metabolism

Substances

  • PPAR gamma
  • Proto-Oncogene Proteins c-akt
  • TOR Serine-Threonine Kinases