Increased oxidative damage is a prominent and early feature in Alzheimer disease. We previously crossed Alzheimer disease transgenic (APPsw) model mice with alpha-tocopherol transfer protein knock-out (Ttpa(-/-)) mice in which lipid peroxidation in the brain was significantly increased. The resulting double-mutant (Ttpa(-/-)APPsw) mice showed increased amyloid beta (Abeta) deposits in the brain, which was ameliorated with alpha-tocopherol supplementation. To investigate the mechanism of the increased Abeta accumulation, we here studied generation, degradation, aggregation, and efflux of Abeta in the mice. The clearance of intracerebral-microinjected (125)I-Abeta(1-40) from brain was decreased in Ttpa(-/-) mice to be compared with wild-type mice, whereas the generation of Abeta was not increased in Ttpa(-/-)APPsw mice. The activity of an Abeta-degrading enzyme, neprilysin, did not decrease, but the expression level of insulin-degrading enzyme was markedly decreased in Ttpa(-/-) mouse brain. In contrast, Abeta aggregation was accelerated in Ttpa(-/-) mouse brains compared with wild-type brains, and well known molecules involved in Abeta transport from brain to blood, low density lipoprotein receptor-related protein-1 (LRP-1) and p-glycoprotein, were up-regulated in the small vascular fraction of Ttpa(-/-) mouse brains. Moreover, the disappearance of intravenously administered (125)I-Abeta(1-40) was decreased in Ttpa(-/-) mice with reduced translocation of LRP-1 in the hepatocytes. These results suggest that lipid peroxidation due to depletion of alpha-tocopherol impairs Abeta clearances from the brain and from the blood, possibly causing increased Abeta accumulation in Ttpa(-/-)APPsw mouse brain and plasma.
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http://dx.doi.org/10.1074/jbc.M109.054056 | DOI Listing |
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January 2025
Medical University of South Carolina, Charleston, SC, USA.
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January 2025
Surgical Neurology Branch, NINDS, NIH 10 Center Drive, Bethesda, MD 20892, USA.
Glioblastoma multiforme (GBM) is a devastating, aggressive primary brain tumor with poor patient outcomes and a five-year survival of less than 10%. Significant limitations to effective GBM treatment include poor drug delivery across the blood-brain barrier, drug resistance, and complex genetic tumor alterations. Gene therapy uses a mechanism different from other GBM therapies to reduce tumor growth and enhance antitumor immunity.
View Article and Find Full Text PDFViruses
January 2025
Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, Herestraat 49, 3000 Leuven, Belgium.
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View Article and Find Full Text PDFPharmaceutics
January 2025
CDL Research, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands.
Background/objectives: Glioblastoma is the most common and lethal primary brain tumor. Patients often suffer from tumor- and treatment induced vasogenic edema, with devastating neurological consequences. Intracranial edema is effectively treated with dexamethasone.
View Article and Find Full Text PDFPharmaceutics
January 2025
Key Laboratory of Molecular Biophysics, Institute of Biophysics, School of Health Sciences & Biomedical Engineering, Hebei University of Technology, Tianjin 300401, China.
Brain diseases pose significant treatment challenges due to the restrictive nature of the blood-brain barrier (BBB). Recent advances in targeting macromolecules offer promising avenues for overcoming these obstacles through receptor-mediated transcytosis (RMT). We summarize the current progress in targeting brain drug delivery with macromolecules for brain diseases.
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