Human adipose tissue microvascular endothelial cells secrete PPARγ ligands and regulate adipose tissue lipid uptake.
Human adipose cells cannot secrete endogenous PPARγ ligands and are dependent on unknown exogenous sources. We postulated that the adipose tissue microvascular endothelial cells (aMVECs) cross-talk with the adipose cells for fatty acid (FA) transport and storage and also may secrete PPARγ ligands. We isolated aMVECs from human subcutaneous adipose tissue and showed that in these cells, but not in (pre)adipocytes from the same donors, exogenous FAs increased cellular PPARγ activation and markedly increased FA transport and the transporters FABP4 and CD36. Importantly, aMVECs only accumulated small lipid droplets and could not be differentiated to adipose cells and are not adipose precursor cells. FA exchange between aMVECs and adipose cells was bidirectional, and FA-induced PPARγ activation in aMVECs was dependent on functional adipose triglyceride lipase (ATGL) protein while deleting hormone-sensitive lipase in aMVECs had no effect. aMVECs also released lipids to the medium, which activated PPARγ in reporter cells as well as in adipose cells in coculture experiments, and this positive cross-talk was also dependent on functional ATGL in aMVECs. In sum, aMVECs are highly specialized endothelial cells, cannot be differentiated to adipose cells, are adapted to regulating lipid transport and secreting lipids that activate PPARγ, and thus, regulate adipose cell function.
['Gogg|Silvia|S|', 'Nerstedt|Annika|A|', 'Boren|Jan|J|', 'Smith|Ulf|U|']
D017667:Adipocytes D000273:Adipose Tissue D018955:CD36 Antigens D042783:Endothelial Cells D050556:Fatty Acid-Binding Proteins D005227:Fatty Acids D006801:Humans D008024:Ligands D008049:Lipase D050356:Lipid Metabolism D008055:Lipids D055806:Microvessels D047495:PPAR gamma D050151:Subcutaneous Fat
Adipose tissue endothelial cells Cell Biology