CNRS. France: Consuming oils with high polyunsaturated fatty
acid content, in particular those containing omega-3s, is beneficial for
the health. But the mechanisms underlying this phenomenon are poorly
known. Researchers at the Institut de Pharmacologie Moléculaire et
Cellulaire (CNRS/Université Nice Sophia Antipolis), the Unité
Compartimentation et Dynamique Cellulaires (CNRS/Institut Curie/UPMC),
the INSERM and the Université de Poitiers investigated the
effect of lipids bearing polyunsaturated chains when they are integrated
into cell membranes. Their work shows that the presence of these lipids
makes the membranes more malleable and therefore more sensitive to
deformation and fission by proteins. These results, published on August
8, 2014 in Science, could help explain the extraordinary efficacy of endocytosis in neuron cells.
Consuming polyunsaturated fatty acids (such as omega
-
3 fatty acids) is
good
for
the
health. The effects
range from neuron
al
differentiation to protection against cerebral ischemia
.
However the molecular
mechanisms
underlying
these effects are poorly understood
, prompting
researchers
to
focus on the role of
these fatty acids in cell membrane function.
For a cell to function properly, the membrane must be able to
deform
and
divide into
small vesicles. This
phenomenon is called
endocytosis. Generally
,
these vesicles allow the cells to encapsulate molecules and
transport them.
In neurons, these synaptic vesicles will act as a transmission pathway to the synapse for
nerve messages. They are formed inside the cell, then they move to its exterior and fuse with its
membrane, to transmit the neurotransmitters that they contain. Then they reform in less than a tenth of a
second: this is synaptic recycling.
In the work
published
in
Science
, the researchers
show that cell
-
or artificial membranes rich in
polyunsaturated lipids are much more sensitive to the action of two proteins, dynamin and endophilin,
which
facilitate membrane
deform
ation
and
fission
.
Other measurements in the study and in simulations
suggest that these lipids also make the membranes more malleable. By
facilitating
the
deformation
and
scission necessary for endocytosis, the presence of polyunsaturated lipids could explain rapid synaptic
vesicle recycling. The abunda
nce of these lipids in the brain could then represent a major advantage for
cognitive function.
This work partially
sheds light on the mode of action of
omega
-
3.
Considering
that
the
body
cannot
synthesize them and
that they can only be supplied by
a suit
able diet (rich in oily fish, etc.), it seems
important to continue this work
to
understand the link between the functions
performed by
these lipids in
the neuron
al
membrane and their health benefits.