reSOLUTION_Research_09_Neuroscience - Leica Microsystems

suPerresolution
fig. 2: fluorescence image of a rat
neuron labelled with three colors: a
presynaptic marker (blue), a postsynaptic
marker (red), and a glutamate
receptor (green). the white color at
the tip of the dendritic spines indicates
an accumulation of receptors. © cnrs
Photothèque / magali mondin, daniel
choquet, laboratory: umr5091 – Physiologie
cellulaire de la synapse (Pcs)
– bordeaux.
fig. 3: this sted image shows a
Phaloidin-atto647n stain of actin in a
cultured hippocampal neuron.
18 resolutioN
investigations and even studies of living organisms.
only then can we gain a better understanding of how
learning and memory are actually influenced by the
regulation of receptor movements.
on the other hand, we intend to research receptor
mobility within the synapse on a nanometer scale
down to the smallest detail in order to find out, for
example, how scaffold proteins are involved in the regulation
of receptor mobility. our working hypothesis
is: different information speeds and regulations are
directly related to learning and memory.
What is the relevance of your work for the
research of neuronal diseases?
today, we assume that changes or malfunctions at
synapses play a definite role in neuronal and psychological
disorders. that’s why not only neurodegenerative
diseases, but also epilepsy or autism are also
called synaptopathies. of course, our basic molecu-
lar research of the animal model is still far from being
clinically relevant, but our work is already linked to
that of our colleagues in pathology.
for instance, we have begun, using animal models, to
examine the defects in receptor trafficking that are
observed in alzheimer’s and Parkinson’s disease. a
whole department of the inb is occupied with neurodegenerative
diseases.
Heading the bic is no doubt an added
advantage for your research?
in bordeaux, i had the dual function as head of a research
group and Head of the imaging facility right
from the beginning. i have taken care to make the
imaging tools we develop for our own experiments
available to the entire community. since then, the facility
has steadily grown – like my research group. in
its present size and function as core facility, the bic
has evolved from the fusion of the light microscopy
(lm), electron microscopy (em) and the plant imaging
facility.
We are extremely successful with the further development
of imaging technologies. in 2002, we
managed to obtain the first live images of the movements
of amPa receptors (amPar), a sub-group
of the glutamate receptors, in the cell membrane
by using a relatively crude approach of tracking by
video microscopy of micrometer-sized latex beads
bound via antibodies to amPar subunits. However,
this method is not suitable for tracking receptors inside
the synapse. together with the physics group of
bordeaux 1, we then started developing single molecule
detection techniques. We were the first group
in europe to apply this technique successfully to
living neurons. another method we developed is the
photothermal imaging of nanogold particles to track
receptors in live neurons for long periods. although
the gold particles do not bleach or blink, and allowing
theoretically infinite recording times, spontaneous
photothermal signals from mitochondria may interfere
with the tracking of gold particles.
of course, we are currently devoting a lot of our attention
to superresolution technologies, which are
extremely important for neuroscientific research.
apart from single molecule detection, we use sted
microscopy and Palm. beyond this, we have also developed
a new superresolution technique in the last
few years called Paint. this point-accumulation-forimaging-in-nanoscale-topography
method allows dynamic
superresolution imaging of arbitrary membrane
proteins in living cells. in a recent paper we published
a further development of this approach called uPaint
(universal Paint). this method is based on continuously
and stochastically labeling membrane surface