Endocytosis in cultured neurons is altered by chronic alcohol exposure.
Endocytosis is required for many cellular pivotal processes, including membrane recycling, nutrient uptake, and signal transduction. This complex process is particularly relevant in polarized cells, such as neurons. Previous studies have demonstrated that alcohol alters intracellular traffic, including endocytosis, in several cell types. However, information on the effect of chronic alcohol exposure on this process in neurons is scarce. As an approach, we investigated the effect of alcohol exposure on the internalization of two widely used endocytic markers, albumin and transferrin, in developing hippocampal neurons in primary culture. The effect of this treatment on the levels of several representative proteins involved in the endocytic process was also analyzed. Some of these proteins are also involved in the organization of the actin cytoskeleton. Pretreatment of cells with inhibitors chlorpromazine or nystatin indicates that albumin is internalized mainly by caveolin-dependent endocytosis. On the other hand, alcohol decreases the endocytosis of both markers, although no qualitative changes in the distribution of either of these molecules were observed. Finally, the effect of ethanol on the proteins analyzed was heterogeneous. Alcohol decreases the levels of clathrin, AP-2, SNX9, Rab5, Rab11, EEA1, Cdc42, or RhoA but increases the amount of Arf6. Moreover, alcohol does not affect the levels of caveolin1, dynamin1, Rab7, and LAMP2. This toxic effect of alcohol on endocytosis could affect some of the important neuronal activities, which depend on this process, including cell signaling. Our results in neurons also stress the notion that one of the main targets of ethanol is intracellular transport.
Centro de Investigación, Hospital Universitario La Fe, Valencia, Spain.
María P
MP
Marín
Guillermo
G
Esteban-Pretel
Xavier
X
Ponsoda
Ana M
AM
Romero
Raúl
R
Ballestín
Carlos
C
López
Luis
L
Megías
Joaquín
J
Timoneda
Asunción
A
Molowny
Juan J
JJ
Canales
Jaime
J
Renau-Piqueras
D000418:Albumins / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D002478:Cells, Cultured; D002492:Central Nervous System Depressants / Q000378:metabolism / Q000633:toxicity*; D002966:Clathrin / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects* / Q000502:physiology; D011992:Endosomes / Q000187:drug effects* / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism / Q000633:toxicity*; D005260:Female; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000196:embryology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D051381:Rats; D014168:Transferrin / Q000378:metabolism
D000418:Albumins; D015415:Biomarkers; D002492:Central Nervous System Depressants; D002966:Clathrin; D009419:Nerve Tissue Proteins; D014168:Transferrin; D000431:Ethanol