Von Willebrand Factor permeates small vessels in CADASIL and inhibits smooth muscle gene expression.
OBJECTIVE
CADASIL (cerebral autosomal dominant arteriopathy subcortical infarcts and leukoencephalopathy) is a genetic disorder hallmarked by ischemic stroke and vascular dementia. Characteristic pathological changes in the vasculature include thickening of small arteries and accumulation of heterogeneous material within the vessel wall. We tested whether endothelial von Willebrand factor (vWF) accumulates in CADASIL vessels and whether exposure of smooth muscle cells to vWF alters the expression of smooth muscle gene expression.


METHODS
Brain sections obtained at autopsy from six North American CADASIL patients were examined using immunohistochemistry for vWF and IgG. Rat aortic smooth muscle cells (A7R5 cells) were tested for binding to infrared-tag labeled vWF. Finally, A7R5 cells were exposed to vWF, and expression of mature smooth muscle marker genes was analyzed by quantitative reverse transcriptase PCR.


RESULTS
vWF is expressed in the penetrating arterial walls in all CADASIL samples. IgG, a marker of serum extravasation, was present only in a minority of arterial walls. vWF binds to smooth muscle cells in vitro, and low concentrations of vWF rapidly activate c-fos, EGR, TSP1, and c-myc while specifically inhibiting RNA encoding smooth muscle actin, calponin, and SM22.


CONCLUSIONS
These data demonstrate that vWF, likely produced by the endothelium, permeates the vessel wall of CADASIL brains. Exposure of smooth muscle cells to vWF results in reduction of specific RNAs required for normal vascular homeostasis. This is the first report of accumulation of a protein within CADASIL vessels that inhibits vascular gene expression and implicates a role for vWF beyond hemostasis.
Departments of Neurology (X.Z., H.M., M.M.W.), Molecular and Integrative, Physiology (J.S., M.M.W.), and Pathology (M.B.), University of Michigan Medical School, Ann Arbor, MI 48109; Department of Neurology, Veterans Administration Ann Arbor Healthcare, System, Ann Arbor, MI 48105 (M.M.W); Institute for Neuropathology, UniversitatsSpital, CH-8091 Zurich (E.J.R.); Department of Pathology and Center for Alzheimer's Disease and Related Disorders, Southern Illinois University School of Medicine, Springfield, IL 62794 (B.E.M.); Departments of Pathology (M. B.S.L.), Neurology (B.B.W.), and Public Health Sciences (B.B.W.), University of Virginia, Charlottesville, VA 22908.
Xiaojie
X
Zhang
He
H
Meng
Mila
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Blaivas
Elisabeth J
EJ
Rushing
Brian E
BE
Moore
Jessica
J
Schwartz
M Beatriz S
MB
Lopes
Bradford B
BB
Worrall
Michael M
MM
Wang