L1 cell adhesion molecule signaling is inhibited by ethanol in vivo.
BACKGROUND
Fetal alcohol spectrum disorder is an immense public health problem. In vitro studies support the hypothesis that L1 cell adhesion molecule (L1) is a target for ethanol (EtOH) developmental neurotoxicity. L1 is critical for the development of the central nervous system. It functions through signal transduction leading to phosphorylation and dephosphorylation of tyrosines on its cytoplasmic domain. The function of L1 is also dependent on trafficking through lipid rafts (LRs). Our hypothesis is that L1 is a target for EtOH neurotoxicity in vivo. Our objective is to demonstrate changes in L1 phosphorylation/dephosphorylation and LR association in vivo.


METHODS
Rat pups on postnatal day 6 are administered 4.5, 5.25, and 6 g/kg of EtOH divided into 2 doses 2 hours apart, then killed. Cerebella are rapidly frozen for assay. Blood is analyzed for blood EtOH concentration. L1 tyrosine phosphorylation is determined by immunoprecipitation and dephosphorylation of tyrosine 1176 determined by immunoblot. LRs are isolated by sucrose density gradient, and the distribution of L1 in LRs is determined.


RESULTS
EtOH at all doses reduced the relative amount of Y1176 dephosphorylation as well as the relative amount of L1 phosphorylated on other tyrosines. The proportion of L1 present in LRs is significantly increased in pups who received 6 g/kg EtOH compared to intubated controls.


CONCLUSIONS
L1 is a target for EtOH developmental neurotoxicity in vivo.
Department of Neuroscience, Lerner Research Institute, Children's Hospital, The Cleveland Clinic, Cleveland, Ohio, USA.
Yoav
Y
Littner
Ningfeng
N
Tang
Min
M
He
Cynthia F
CF
Bearer
D000818:Animals; D000831:Animals, Newborn; D015536:Down-Regulation / Q000187:drug effects* / Q000502:physiology; D000431:Ethanol / Q000008:administration & dosage*; D005260:Female; D008297:Male; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism; D039842:Neural Cell Adhesion Molecule L1 / Q000037:antagonists & inhibitors* / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology
D039842:Neural Cell Adhesion Molecule L1; D000431:Ethanol