Endothelial Cell CD36 Regulates Membrane Ceramide Formation, Exosome Fatty Acid Delivery to Tissues and Circulating Fatty Acid Levels
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ABSTRACT: Endothelial cell (EC) CD36 controls tissue fatty acid (FA) uptake. Here we examined how ECs transfer FAs. FA interaction with apical membrane CD36 induced Src phosphorylation of caveolin-1 tyrosine-14 (Cav-1Y14) and ceramide generation in caveolae. Fission of the caveolae yielded vesicles containing FAs, CD36 and ceramide that were secreted basolaterally as small (80-100nm) exosome-like extracellular vesicles (sEVs). We visualized EC transfer of FAs in sEVs to underlying myotubes in transwells. In mice with EC-expression of the exosome marker emeraldGFP-CD63, muscle fibers accumulated circulating FAs in emGFP-labeled puncta. The FA-sEV pathway was mapped through its suppression by CD36 depletion, blocking actin-remodeling, Src inhibition, Cav-1Y14 mutation, and neutral sphingomyelinase 2 inhibition. Suppression of sEV formation in mice reduced muscle FA uptake, raised circulating FAs, which remained in blood vessels, and lowered glucose, mimicking prominent Cd36-/- phenotypes. The findings show that FA uptake influences membrane ceramide, endocytosis, and EC communication with parenchymal cells.
ORGANISM(S): Homo sapiens
PROVIDER: GSE235988 | GEO | 2023/07/02
REPOSITORIES: GEO
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