Marine lipids
Modulation of endothelial vascular
permeability by marine ether lipids
H. Youmine, K. Marigny, A. Hichami, C.A.E. Martin-Chouly,
A. Legrand.
Université de Rennes 1, faculté des sciences pharmaceutiques et biologiques, laboratoire
de pharmacodynamie et pharmacologie moléculaire, 2 av. du Pr Léon Bernard,
35043 Rennes Cedex, France - hind.youmine@univ-rennesl.fr
Abstract
The 1 -O-alkylglycerols (alkyl-Gro), naturally occurring compounds
abundant in shark liver oil, protect patients from radiotherapy side
effects and inhibit neoplastic growth. However, the therapeutic mechanisms are not well understood. It might be mediated by alkyl-Gro
incorporation into membrane phospholipids (PL) and then interfere
with cell signaling through direct contact with membrane enzymes or
through alkyl-Gro metabolites interfering with PKC activation by
lipidic second messengers.
We investigated the kinencs of incorporation of [ 3 H]-labelled alkylGro natural mixture ( 10 -5 M, 92.5 mCi/mmol) into PI. of porcine aortic
endothelial cells (PAEC). Then we studied the influence of alkyl-Gro
on endothelial monolayer permeability which is PKC-dependent, using
primary culture of PAEC on microporous membrane support. The cells
were incubated with 10 5 M alkyl-Gro for 24 h before quantifying
transendothelial albumin flux, and stimulated by the calcium ionophore A23187 (10 - 6 M) or the phorbol 12-myristate 13-acetate (PMA)
(2.10 -7 M) which activates PKC. Then, after [ 3 H]-alkyl-Gro incorporation (10 - 5 M, 370 mCi/mmol), we searched for the PKC inhibitor,
[
3 H]-1 -O-alkyl-2-acylglycerol ([ 3 H]-alkyl-acyl-Gro), after 2 minstimulation by PMA (2.10 -7 M) or by A231 87 ( 10 - 6 M).
Ourdata showed that [ 3 H]-alkyl-Gro incorporated predominantly into
membrane phosphatidylcholine (PC) and 6.58 ± 0.35% of initial radioactivity was found in PC after 24 h-incubation. PMA or A2 3187 induced
a significant raise in the permeability to albumin by 38.88 ± 1 6.81 %
(p<0.05, n=8) and 4 3.41 ± 6.55% (p<0.05, n 5) over control, respectively. After incorporation, alkyl-Gro had no effect on basal permeability but abolished the effect of PMA and significantly decreased
A23187-induced raise in endothelial permeability by 35.45 ± 9-76%
below the control level. In parallel, after 2 min-stimulation with
A23187, we observed a significant increase in the production of [ 3 H]alkyl-acyl-Gro by PAEC that incorporated [ 3 H]-alkyl-Gro (58.14
±9.28% over control, p<0.01, n=12), whereas PMA did not increase
[ 3 H]-alkyl-acyl-Gro biosynthesis.
This study showed that alkyl-Gro incorporation into PAEC membrane
PC results in an inhibition of the endothelial stimulated permeability.
146
Modulation of endothelial vascular
permeability by marine ether lipids
H. Youmine, K. Marigny, A. Hichami, C.A.E. Martin-Chouly,
A. Legrand.
Université de Rennes 1, faculté des sciences pharmaceutiques et biologiques, laboratoire
de pharmacodynamie et pharmacologie moléculaire, 2 av. du Pr Léon Bernard,
35043 Rennes Cedex, France - hind.youmine@univ-rennesl.fr
Abstract
The 1 -O-alkylglycerols (alkyl-Gro), naturally occurring compounds
abundant in shark liver oil, protect patients from radiotherapy side
effects and inhibit neoplastic growth. However, the therapeutic mechanisms are not well understood. It might be mediated by alkyl-Gro
incorporation into membrane phospholipids (PL) and then interfere
with cell signaling through direct contact with membrane enzymes or
through alkyl-Gro metabolites interfering with PKC activation by
lipidic second messengers.
We investigated the kinencs of incorporation of [ 3 H]-labelled alkylGro natural mixture ( 10 -5 M, 92.5 mCi/mmol) into PI. of porcine aortic
endothelial cells (PAEC). Then we studied the influence of alkyl-Gro
on endothelial monolayer permeability which is PKC-dependent, using
primary culture of PAEC on microporous membrane support. The cells
were incubated with 10 5 M alkyl-Gro for 24 h before quantifying
transendothelial albumin flux, and stimulated by the calcium ionophore A23187 (10 - 6 M) or the phorbol 12-myristate 13-acetate (PMA)
(2.10 -7 M) which activates PKC. Then, after [ 3 H]-alkyl-Gro incorporation (10 - 5 M, 370 mCi/mmol), we searched for the PKC inhibitor,
[
3 H]-1 -O-alkyl-2-acylglycerol ([ 3 H]-alkyl-acyl-Gro), after 2 minstimulation by PMA (2.10 -7 M) or by A231 87 ( 10 - 6 M).
Ourdata showed that [ 3 H]-alkyl-Gro incorporated predominantly into
membrane phosphatidylcholine (PC) and 6.58 ± 0.35% of initial radioactivity was found in PC after 24 h-incubation. PMA or A2 3187 induced
a significant raise in the permeability to albumin by 38.88 ± 1 6.81 %
(p<0.05, n=8) and 4 3.41 ± 6.55% (p<0.05, n 5) over control, respectively. After incorporation, alkyl-Gro had no effect on basal permeability but abolished the effect of PMA and significantly decreased
A23187-induced raise in endothelial permeability by 35.45 ± 9-76%
below the control level. In parallel, after 2 min-stimulation with
A23187, we observed a significant increase in the production of [ 3 H]alkyl-acyl-Gro by PAEC that incorporated [ 3 H]-alkyl-Gro (58.14
±9.28% over control, p<0.01, n=12), whereas PMA did not increase
[ 3 H]-alkyl-acyl-Gro biosynthesis.
This study showed that alkyl-Gro incorporation into PAEC membrane
PC results in an inhibition of the endothelial stimulated permeability.
146