Pan European Networks: Science & Technology
06
155
PROFILE
Per Hammarström
Project Co-ordinator
LUPAS Project
tel: +46 13 285690
are readily detectable by LCPs. The ability of LCPs to discriminate
between different structures of fibrillar and pre-fibrillar aggregates
is of great importance for Alzheimer’s disease. These features
render the LCPs superior to other small molecule probes for
molecular diagnostics. Synthesis of LCPs were scaled up into
gram scale amounts and are now being implemented within a
variety of subprojects within LUPAS partner labs and within
collaborations all over Europe and worldwide.
Multiphoton imaging is a preferable technique for studying
protein aggregation diseases in real-time in transgenic mouse
models and we have shown that the unique optical properties of
LCPs make these dyes highly efficient for multiphoton
in vivo
imaging. Several LCPs cross the blood brain barrier which
enables specific labelling of amyloid plaques (Aß) and
intraneuronal Neurofibrillary tangles (Tau) in the parenchyma of
the brain, as well as Aß amyloid in blood vessels so called
cerebral amyloid angiopathy.
In vivo
imaging of protein deposits
in living mice was demonstrated using distinct LCPs, and these
LCP scaffolds are well tolerated by mice even during longer time
periods and repetitive injections. The latter is imperative, because
the final goal of LUPAS is to achieve an LCP-based agent for non-
invasive clinical diagnostics of AD and prion diseases.
From a diagnostic perspective, the LCPs were employed on post-
mortem tissue sections from patients with neurodegenerative
diseases. The LCP selectively stain the protein deposits and expose
these major pathological hallmarks of either AD or prion diseased
brain. The identification can easily be done and distinguished due
to the colour emitted from the LCP bound to the different entities
(Fig. 2). Hence, the LCP technique shows excellent promise for
being implemented as a complementary technique in routine
clinical diagnostics.Work towards fluorescence detection of
aggregated protein as biomarkers in cerebral spinal fluid of
Alzheimer’s disease and control patients has been performed, but
results so far have not been conclusive.
Optical probes are not the preferable agents for non-invasive
imaging in humans, due to the limitations of optical imaging. In
this regard, the LUPAS consortium aimed to broaden the scope to
develop novel multimodal LCPs that can be used for both optical
imaging and magnetic resonance imaging. MRI is today a standard
technique for imaging of pathological conditions in humans, but
the contrast is rather limited. Contrast agents based on
paramagnetic nanoparticles and nanocomplexes (MNPs) hold
great promise for MRI.Within LUPAS a variety of nanoparticles were
synthesised for enhanced T1 and T2 relaxation dispersion making
these potentially useful as contrast agents for MRI. In addition, the
first prototype of a LCP-MNP conjugate can specifically target
amyloid
in vitro,
in tissue samples, and promising results have also
been obtained
in vivo
in transgenic mice.
Therapy
Disease modifying treatments for neurodegenerative diseases are
scarce and non-existent for prion diseases. Because the LCP
molecules show selective binding towards the culprit – the
aggregated proteins – their potential as therapeutic agents against
prion diseases was evaluated within LUPAS.Work on tissue
sections and cell cultures show efficient LCP-mediated reduction
in prion infectivity as a result of unexpected stabilisation of prion
aggregates. This mechanistic insight opens up completely new
avenues for targeting both prion disease and other
neurodegenerative diseases based on hyperstabilisation rather
than clearance of the misfolded protein culprits.
Final outcome and future perspectives
There is a tremendous need for quantitative diagnostic methods
for early detection and evaluation of neurodegenerative disorders,
such as Alzheimer’s disease and prion diseases. The need is
underlined by the recent development of proposed therapeutical
interventions targeting disease, so called disease modifiers,
including immune therapy. Herein, quantitative physical outcome
measures are urgently needed in terms of amyloid pathology
within living patients.
The LUPAS project exemplifies that broad cross-disciplinary
expertise within diverse subjects can realise unmet needs within
biomedicine. The realistic prognosis is that it will take a few more
years to validate this technology in the preclinical phase prior to
going to the clinic. The LUPAS consortium strives for continuing
towards these goals beyond the project time frame pending future
generous support from various stakeholders such as industry,
academia, patients and politicians.
Fig. 2 LCP fluorescence from protein aggregates in frozen brain tissue
from human patients with prion disease: a) Creutzfeldt-Jakob Disease
(CJD)type I, b) CJD type II, c) Inherited prion disease Gerstmann-
Straussler-Scheinker Disease (GSS). d) Amyloid plaque in transgenic
mouse with Alzheimer disease pathology.
Image courtesy of Dr Henning Leske and Dr Sofie Nystrom
NEURODEGENERATIVE RESEARCH
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