Exosomes account for vesicle-mediated transcellular transport of activatable phospholipases and prostaglandins.
Exosomes are bioactive vesicles released from multivesicular bodies (MVB) by intact cells and participate in intercellular signaling. We investigated the presence of lipid-related proteins and bioactive lipids in RBL-2H3 exosomes. Besides a phospholipid scramblase and a fatty acid binding protein, the exosomes contained the whole set of phospholipases (A2, C, and D) together with interacting proteins such as aldolase A and Hsp 70. They also contained the phospholipase D (PLD) / phosphatidate phosphatase 1 (PAP1) pathway leading to the formation of diglycerides. RBL-2H3 exosomes also carried members of the three phospholipase A2 classes: the calcium-dependent cPLA(2)-IVA, the calcium-independent iPLA(2)-VIA, and the secreted sPLA(2)-IIA and V. Remarkably, almost all members of the Ras GTPase superfamily were present, and incubation of exosomes with GTPgammaS triggered activation of phospholipase A(2) (PLA(2))and PLD(2). A large panel of free fatty acids, including arachidonic acid (AA) and derivatives such as prostaglandin E(2) (PGE(2)) and 15-deoxy-Delta(12,14)-prostaglandinJ(2) (15-d PGJ(2)), were detected. We observed that the exosomes were internalized by resting and activated RBL cells and that they accumulated in an endosomal compartment. Endosomal concentrations were in the micromolar range for prostaglandins; i.e., concentrations able to trigger prostaglandin-dependent biological responses. Therefore exosomes are carriers of GTP-activatable phospholipases and lipid mediators from cell to cell.
Subra
Caroline
C
Metabolism, Oncogenesis and Cell Differentiation Group, INSERM Research Center 563, Pathophysiology Center of Toulouse Purpan, Hôpital Purpan, Toulouse, France.
Grand
David
D
Laulagnier
Karine
K
Stella
Alexandre
A
Lambeau
Gérard
G
Paillasse
Michael
M
De Medina
Philippe
P
Monsarrat
Bernard
B
Perret
Bertrand
B
Silvente-Poirot
Sandrine
S
Poirot
Marc
M
Record
Michel
M
D001692:Biological Transport; D002460:Cell Line; D015232:Dinoprostone / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D055354:Exosomes / Q000187:drug effects / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006801:Humans; D008066:Lipolysis; D000073718:Pancreatitis-Associated Proteins; D010711:Phosphatidate Phosphatase / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism; D010740:Phospholipases / Q000378:metabolism*; D054467:Phospholipases A2 / Q000378:metabolism; D015230:Prostaglandin D2 / Q000031:analogs & derivatives / Q000378:metabolism; D011453:Prostaglandins / Q000378:metabolism*; D020543:Proteome / Q000378:metabolism
D000073718:Pancreatitis-Associated Proteins; D011453:Prostaglandins; D020543:Proteome; C000612141:REG3A protein, human; C037112:9-deoxy-delta-9-prostaglandin D2; D006160:Guanosine Triphosphate; D010740:Phospholipases; D054467:Phospholipases A2; D010711:Phosphatidate Phosphatase; C105606:phospholipase D2; D010739:Phospholipase D; D015232:Dinoprostone; D015230:Prostaglandin D2