Caveolin-1 regulates lipid droplet metabolism in endothelial cells via autocrine prostacyclin-stimulated, cAMP-mediated lipolysis.
J Biol Chem
; 293(3): 973-983, 2018 01 19.
Article
in En
| MEDLINE
| ID: mdl-29203526
ABSTRACT
Lipid droplets (LD) are dynamic organelles involved in intracellular lipid metabolism in almost all eukaryotic cells, and LD-associated proteins tightly regulate their dynamics. One LD coat protein is caveolin-1 (Cav-1), an essential component for caveola assembly in highly differentiated cells, including adipocytes, smooth muscle cells, and endothelial cells (EC). However, the role of Cav-1 in LD dynamics is unclear. Here we report that EC lacking Cav-1 exhibit impaired LD formation. The decreased LD formation is due to enhanced lipolysis and not caused by reduced triglyceride synthesis or fatty acid uptake. Mechanistically, the absence of Cav-1 increased cAMP/PKA signaling in EC, as indicated by elevated phosphorylation of hormone-sensitive lipase and increased lipolysis. Unexpectedly, we also observed enhanced autocrine production of prostaglandin I2 (PGI2, also called prostacyclin) in Cav-1 KO EC, and this PGI2 increase appeared to stimulate cAMP/PKA pathways, contributing to the enhanced lipolysis in Cav-1 KO cells. Our results reveal an unanticipated role of Cav-1 in regulating lipolysis in non-adipose tissue, indicating that Cav-1 is required for LD metabolism in EC and that it regulates cAMP-dependent lipolysis in part via the autocrine production of PGI2.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Epoprostenol
/
Cyclic AMP
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Endothelial Cells
/
Caveolin 1
/
Lipolysis
Limits:
Animals
Language:
En
Journal:
J Biol Chem
Year:
2018
Type:
Article