A role for lipid rafts in the protection afforded by docosahexaenoic acid against ethanol toxicity in primary rat hepatocytes.
Abstract
: Previously, we demonstrated that eicosapentaenoic acid enhanced ethanol-induced oxidative stress and cell death in primary rat hepatocytes via an increase in membrane fluidity and lipid raft clustering. In this context, another n-3 polyunsaturated fatty acid, docosahexaenoic acid (DHA), was tested with a special emphasis on physical and chemical alteration of lipid rafts. Pretreatment of hepatocytes with DHA reduced significantly ethanol-induced oxidative stress and cell death. DHA protection could be related to an alteration of lipid rafts. Indeed, rafts exhibited a marked increase in membrane fluidity and packing defects leading to the exclusion of a raft protein marker, flotillin. Furthermore, DHA strongly inhibited disulfide bridge formation, even in control cells, thus suggesting a disruption of protein-protein interactions inside lipid rafts. This particular spatial organization of lipid rafts due to DHA subsequently prevented the ethanol-induced lipid raft clustering. Such a prevention was then responsible for the inhibition of phospholipase C-γ translocation into rafts, and consequently of both lysosome accumulation and elevation in cellular low-molecular-weight iron content, a prooxidant factor. In total, the present study suggests that DHA supplementation could represent a new preventive approach for patients with alcoholic liver disease based upon modulation of the membrane structures.
Keywords
4-hydroxynonenal
DHA
EPA
EPR
Ethanol
GM1
GPI
H(2)FDA
HNE
LMW iron
Lipid peroxidation
Lipid rafts
MAL-6
O-(2
6-pentafluorobenzyl)hydroxylamine hydrochloride
O-PFB
Oxidative stress
PFBHA*HCl
PLCγ1
ROS
dihydrofluorescein diacetate
docosahexaenoic acid
eicosapentaenoic acid
electron paramagnetic resonance
glycosylphosphatidylinositol
low-molecular-weight iron
monosialotetrahexosyl ganglioside
n-3 PUFA
n-3 Polyunsaturated fatty acids
n-3 polyunsaturated fatty acid
pentafluorobenzyl-oxime
phospholipase C γ1
reactive oxygen species
GSH: reduced glutathione
tetramethyl-4-maleimidopiperidine-1-oxyl
Domains
Life Sciences [q-bio]
Origin : Files produced by the author(s)
Loading...