TY - JOUR
T1 - Fluorescent analogues of plasma membrane sphingolipids are sorted to different intracellular compartments in astrocytes
T2 - Harmful effects of chronic ethanol exposure on sphingolipid trafficking and metabolism
AU - Tomás, Mónica
AU - Durán, Juan M.
AU - Lázaro-Diéguez, Francisco
AU - Babià, Teresa
AU - Renau-Piqueras, Jaime
AU - Egea, Gustavo
PY - 2004/4/9
Y1 - 2004/4/9
N2 - Sphingolipids are basic constituents of cellular membranes and are essential for numerous functions such as intracellular signalling. They are transported along the exocytic and endocytic pathways in eukaryotic cells. After endocytosis, fluorescent-labelled sphingolipids are sorted to distinct intracellular organelles prior to recycling (via early/recycling endosomes) or degradation (late endosomes/lysosomes). Here we examine, in primary cultures of rat astrocytes, the internalisation routes followed by C6-NBD- glucosylceramide (NBD-GlcCer) and C6-NBD-sphingomyelin (NBD-SM) and the effects of ethanol on their endocytic trafficking. Endocytosed plasma membrane NBD-GlcCer and NBD-SM are diverted to the Golgi apparatus and lysosomes, respectively. These different internalisation pathways are maintained regardless of the differentiation stage of astrocytes. Chronic ethanol exposure did not alter this endocytic sorting, but delayed the internalisation of both NBD-sphingolipids. Moreover, ethanol also stimulated the in situ metabolism of NBD-ceramide to NBD-GlcCer and NBD-SM. We conclude that in rat astrocytes internalised plasma membrane NBD-sphingolipids are sorted to different subcellular compartments. The exposure to chronic ethanol perturbed the lipid endocytic process and stimulated the de novo synthesis of NBD-sphingolipids, shifting the balance of sphingolipid metabolism in favour of the sphingomyelin pathway.
AB - Sphingolipids are basic constituents of cellular membranes and are essential for numerous functions such as intracellular signalling. They are transported along the exocytic and endocytic pathways in eukaryotic cells. After endocytosis, fluorescent-labelled sphingolipids are sorted to distinct intracellular organelles prior to recycling (via early/recycling endosomes) or degradation (late endosomes/lysosomes). Here we examine, in primary cultures of rat astrocytes, the internalisation routes followed by C6-NBD- glucosylceramide (NBD-GlcCer) and C6-NBD-sphingomyelin (NBD-SM) and the effects of ethanol on their endocytic trafficking. Endocytosed plasma membrane NBD-GlcCer and NBD-SM are diverted to the Golgi apparatus and lysosomes, respectively. These different internalisation pathways are maintained regardless of the differentiation stage of astrocytes. Chronic ethanol exposure did not alter this endocytic sorting, but delayed the internalisation of both NBD-sphingolipids. Moreover, ethanol also stimulated the in situ metabolism of NBD-ceramide to NBD-GlcCer and NBD-SM. We conclude that in rat astrocytes internalised plasma membrane NBD-sphingolipids are sorted to different subcellular compartments. The exposure to chronic ethanol perturbed the lipid endocytic process and stimulated the de novo synthesis of NBD-sphingolipids, shifting the balance of sphingolipid metabolism in favour of the sphingomyelin pathway.
KW - Alcohol
KW - Endocytosis
KW - Endosome
KW - Glial cell
KW - Golgi apparatus
KW - NBD-lipid
UR - http://www.scopus.com/inward/record.url?scp=1842636819&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=1842636819&partnerID=8YFLogxK
U2 - 10.1016/S0014-5793(04)00245-5
DO - 10.1016/S0014-5793(04)00245-5
M3 - Article
C2 - 15063723
AN - SCOPUS:1842636819
SN - 0014-5793
VL - 563
SP - 59
EP - 65
JO - FEBS Letters
JF - FEBS Letters
IS - 1-3
ER -