A lipase-independent pathway of lipid release and immune modulation by adipocytes

SE Flaherty III, A Grijalva, X Xu, E Ables, A Nomani… - Science, 2019 - science.org
SE Flaherty III, A Grijalva, X Xu, E Ables, A Nomani, AW Ferrante Jr
Science, 2019science.org
To meet systemic metabolic needs, adipocytes release fatty acids and glycerol through the
action of neutral lipases. Here, we describe a secondary pathway of lipid release from
adipocytes that is independent of canonical lipolysis. We found that adipocytes release
exosome-sized, lipid-filled vesicles (AdExos) that become a source of lipid for local
macrophages. Adipose tissue from lean mice released~ 1% of its lipid content per day via
exosomes ex vivo, a rate that more than doubles in obese animals. AdExos and associated …
To meet systemic metabolic needs, adipocytes release fatty acids and glycerol through the action of neutral lipases. Here, we describe a secondary pathway of lipid release from adipocytes that is independent of canonical lipolysis. We found that adipocytes release exosome-sized, lipid-filled vesicles (AdExos) that become a source of lipid for local macrophages. Adipose tissue from lean mice released ~1% of its lipid content per day via exosomes ex vivo, a rate that more than doubles in obese animals. AdExos and associated factors were sufficient to induce in vitro differentiation of bone marrow precursors into adipose tissue macrophage–like cells. Thus, AdExos are both an alternative pathway of local lipid release and a mechanism by which parenchymal cells can modulate tissue macrophage differentiation and function.
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