The Journal of Neuroscience, December 15, 2002, 22(24):10621-10626
Aberrant Neuronal and Paracellular Deposition of Endostatin in
Brains of Patients with Alzheimer's Disease
Martin H.
Deininger1, *,
Birte A.
Fimmen1, *,
Dietmar
R.
Thal2,
Hermann J.
Schluesener1, and
Richard
Meyermann1
1 Institute of Brain Research, University of Tuebingen
Medical School, D-72076 Tuebingen, Germany, and 2 Institute
of Neuropathology, University of Bonn Medical School, D-53127 Bonn,
Germany
Cerebrovascular pathology is common in Alzheimer's disease (AD)
and is considered to contribute to cerebral malfunction. However, distinct antiangiogenic proteins that accumulate in AD brains have not
yet been identified. Endostatin is a 20 kDa C-terminal fragment of
collagen XVIII that, when added exogenously, inhibits endothelial
proliferation and migration in vitro and angiogenesis and tumor growth in vivo by inducing apoptosis in
endothelial cells.
We produced a monoclonal antibody directed against
endostatin and observed significantly more
(p < 0.0001) immunoreactive cortical
neurons in AD brains compared with age-matched neuropathologically unaltered controls. High numbers of extracellular and frequently perivascular endostatin deposits were detected in the cerebral hemispheres. Double-labeling experiments revealed colocalization of
endostatin in amyloid-
(1-40)
(A
(1-40)), tau protein, and periodic
acid-Schiff stain-positive plaques that were surrounded by focal
gliosis. Western blotting revealed more 20 kDa endostatin in an AD
patient compared with a control. In unstimulated SKNSH supernatants, endostatin was detected that increased predominantly after hypoxia in supernatants and cellular lysates.
A
(1-40) (80 µg/ml) supplementation to SKNSH neurons
for 24 hr completely abolished the release of endostatin.
These data show that endostatin is released by neurons to accumulate in
amyloid plaques in Alzheimer's disease. Induction by hypoxia and
complete abrogation of endostatin release after A
(1-40)
challenge reveals intricate interactions between the two proteins and
opens new avenues for the development of novel treatment strategies of
AD patients.
Key words:
endostatin; amyloid; Alzheimer's disease; deposits; neurons
*
M.H.D. and B.A.F. contributed equally to this work.