Abstract
Accumulation of amyloid beta protein (Aβ) plays a major role in the etiology of Alzheimer’s disease (AD). Aβ is generated from the cleavage of amyloid precursor protein (APP) by beta-site APP-cleaving enzyme 1 (BACE1). There are two factors that reduce of Aβ accumulation in the brain; degradation by peptidases such as neprilysin (NEP) and clearance via two transporters. The low-density lipoprotein receptor related protein 1 (LRP1) is the major transporter that clears Aβ from brain to blood and the receptor for advanced glycation end products (RAGE) is a receptor that transports Aβ from blood to brain. Copper (Cu) has been postulated to play a role in the pathogenesis of AD, especially involved in Aβ aggregation and toxicity. According to a recent study, Cu(II) could reduce Aβ clearance from the brain in cholesterol-fed rabbits. However, the critical mechanism is unclear. This study was purposed to demonstrate whether Cu (II) would alter accumulation of Aβ in brain. We treated 25 and 50 μM CuSO4 for 48-hour in the well-defined neurodevelopmental cell line (PC12), rat choroidal epithelial cell line (Z310), and rat brain endothelial cell line (RBE4) to estimate the effects on Cu(II) exposure in the brain.
Cu(II) increased the levels of Aβ(40) and Aβ(42) in the PC12 cell medium in a dose-dependent manner compared with control. The mRNA and protein expression levels of APP and BACE1, which play an important role in Aβ generation, were increased in the PC12 cells exposed to Cu(II). NEP expression levels in mRNA and protein were decreased in a dose-dependent manner in PC12 cells treated with Cu(II). In the RBE4 cells, Cu(II) decreased LRP1 levels and increased RAGE levels in mRNA and protein compared with control. Moreover, Cu(II) decreased the clearance of Aβ using the blood-brain barrier (BBB) transport study. However, in the Z310 cells, Cu(II) didn’t change the levels of LRP1 and RAGE in mRNA and protein. These results implied that Cu(II) increased Aβ accumulation in the brain by increasing Aβ production but decreasing Aβ degradation in the brain parenchyma and interfering with clearance of Aβ via the BBB.
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References
Mattson, M. P. Pathways towards and away from Alzheimer’s disease. Nature 430:631–639 (2004).
Lesne, S. et al. A specific amyloid-beta protein assembly in the brain impairs memory. Nature 440:352–357 (2006).
Bush, A. I., Masters, C. L. & Tanzi, R. E. Copper, betaamyloid, and Alzheimer’s disease: tapping a sensitive connection. Proc Natl Acad Sci USA 100:11193–11194 (2003).
Huang, X. et al. Trace metal contamination initiates the apparent auto-aggregation, amyloidosis, and oligomerization of Alzheimer’s Abeta peptides. J Biol Inorg Chem 9:954–960 (2004).
Mattson, M. P. Gene-diet interactions in brain aging and neurodegenerative disorders. Ann Intern Med 139:441–444 (2003).
Raman, B. et al. Metal ion-dependent effects of clioquinol on the fibril growth of an amyloid {beta} peptide. J Biol Chem 280:16157–16162 (2005).
Martorana, A. et al. Cerebrospinal fluid levels of Abeta42 relationship with cholinergic cortical activity in Alzheimer’s disease patients. J Neural Transm. http://link.springer.com/content/pdf/10.1007%2Fs00702-012-0780-4 (2012).
Ogomori, K. et al. Beta-protein amyloid is widely distributed in the central nervous system of patients with Alzheimer’s disease. Am J Pathol 134:243–251 (1989).
Selkoe, D. J. The cell biology of beta-amyloid precursor protein and presenilin in Alzheimer’s disease. Trends Cell Biol 8:447–453 (1998).
Deane, R., Bell, R. D., Sagare, A. & Zlokovic, B. V. Clearance of amyloid-beta peptide across the bloodbrain barrier: implication for therapies in Alzheimer’s disease. CNS Neurol Disord Drug Targets 8:16–30 (2009).
Donnelly, P. S., Xiao, Z. & Wedd, A. G. Copper and Alzheimer’s disease. Curr Opin Chem Biol 11:128–133 (2007).
Hung, Y. H., Bush, A. I. & Cherny, R. A. Copper in the brain and Alzheimer’s disease. J Biol Inorg Chem 15:61–76 (2010).
Lovell, M. A., Robertson, J. D., Teesdale, W. J., Campbell, J. L. & Markesbery, M. R. Copper, iron and zinc in Alzheimer’s disease senile plaques. J Neurol Sci 158:47–52 (1998).
Huang, X., Moir, R. D., Tanzi, R. E., Bush, A. I. & Rogers, J. T. Redox-active metals, oxidative stress, and Alzheimer’s disease pathology. Ann N Y Acad Sci 1012:153–163 (2004).
Angeletti, B. et al. BACE1 cytoplasmic domain interacts with the copper chaperone for superoxide dismutase-1 and binds copper. J Biol Chem 280:17930–17937 (2005).
Atwood, C. S. et al. Copper mediates dityrosine crosslinking of Alzheimer’s amyloid-beta. Biochemistry 43:560–568 (2004).
Hesse, L., Beher, D., Masters, C. L. & Multhaup, G. The beta A4 amyloid precursor protein binding to copper. FEBS Lett 349:109–116 (1994).
Multhaup, G. et al. The amyloid precursor protein of Alzheimer’s disease in the reduction of copper (II) to copper (I). Science 271:1406–1409 (1996).
Multhaup, G. et al. Copper-binding amyloid precursor protein undergoes a site-specific fragmentation in the reduction of hydrogen peroxide. Biochemistry 37:7224–7230 (1998).
White, A. R. et al. Copper levels are increased in the cerebral cortex and liver of APP and APLP2 knockout mice. Brain Res 842:439–444 (1999).
Acevedo, K. M. et al. Copper promotes the trafficking of the amyloid precursor protein. J Biol Chem 286:8252–8262 (2011).
Shirotani, K. et al. Neprilysin degrades both amyloid beta peptides 1–40 and 1–42 most rapidly and efficiently among thiorphan- and phosphoramidon-sensitive endopeptidases. J Biol Chem 276:21895–21901 (2001).
Maruyama, M. et al. Cerebrospinal fluid neprilysin is reduced in prodromal Alzheimer’s disease. Ann Neurol 57:832–842 (2005).
Yasojima, K., Akiyama, H., McGeer, E. G. & McGeer, P. L. Reduced neprilysin in high plaque areas of Alzheimer brain: a possible relationship to deficient degradation of beta-amyloid peptide. Neurosci Lett 297:97–100 (2001).
Li, M. et al. Copper downregulates neprilysin activity through modulation of neprilysin degradation. J Alzheimers Dis 19:161–169 (2010).
Choi, B. S. & Zheng, W. Copper transport to the brain by the blood-brain barrier and blood-CSF barrier. Brain Res 1248:14–21 (2009).
Zlokovic, B. V. et al. Blood-brain barrier transport of circulating Alzheimer’s amyloid beta. Biochem Biophys Res Commun 197:1034–1040 (1993).
Behl, M., Zhang, Y., Monnot, A. D., Jiang, W. & Zheng, W. Increased beta-amyloid levels in the choroid plexus following lead exposure and the involvement of low-density lipoprotein receptor protein-1. Toxicol Appl Pharmacol 240:245–254 (2009).
Rubenstein, E. Relationship of senescence of cerebrospinal fluid circulatory system to dementias of the aged. Lancet 351:283–285 (1998).
Selkoe, D. J. Toward a comprehensive theory for Alzheimer’s disease. Hypothesis: Alzheimer’s disease is caused by the cerebral accumulation and cytotoxicity of amyloid beta-protein. Ann N Y Acad Sci 924:17–25 (2000).
Shibata, M. et al. Clearance of Alzheimer’s amyloidss(1–40) peptide from brain by LDL receptor-related protein-1 at the blood-brain barrier. J Clin Invest 106:1489–1499 (2000).
Donahue, J. E. et al. RAGE, LRP-1, and amyloid-beta protein in Alzheimer’s disease. Acta Neuropathol 112:405–415 (2006).
Miller, M. C. et al. Hippocampal RAGE immunoreactivity in early and advanced Alzheimer’s disease. Brain Res 1230:273–280 (2008).
Yan, S. D. et al. RAGE and amyloid-beta peptide neurotoxicity in Alzheimer’s disease. Nature 382:685–691 (1996).
Sparks, D. L. & Schreurs, B. G. Trace amounts of copper in water induce beta-amyloid plaques and learning deficits in a rabbit model of Alzheimer’s disease. Proc Natl Acad Sci USA 100:11065–11069 (2003).
Selkoe, D. J. & Schenk, D. Alzheimer’s disease: molecular understanding predicts amyloid-based therapeutics. Annu Rev Pharmacol Toxicol 43:545–584 (2003).
Selkoe, D. J. Clearing the brain’s amyloid cobwebs. Neuron 32:177–180 (2001).
Zlokovic, B. V. The blood-brain barrier in health and chronic neurodegenerative disorders. Neuron 57:178–201 (2008).
Prelli, F. et al. Different processing of Alzheimer’s beta-protein precursor in the vessel wall of patients with hereditary cerebral hemorrhage with amyloidosis-Dutch type. Biochem Biophys Res Commun 151:1150–1155 (1988).
Seubert, P. et al. Isolation and quantification of soluble Alzheimer’s beta-peptide from biological fluids. Nature 359:325–327 (1992).
Rivera-Mancia, S. et al. The transition metals copper and iron in neurodegenerative diseases. Chem Biol Interact 186:184–199 (2010).
Gerhardsson, L., Lundh, T., Minthon, L. & Londos, E. Metal concentrations in plasma and cerebrospinal fluid in patients with Alzheimer’s disease. Dement Geriatr Cogn Disord 25:508–515 (2008).
Lovell, M. A., Robertson, J. D., Teesdale, W. J., Campbell, J. L. & Markesbery, W. R. Copper, iron and zinc in Alzheimer’s disease senile plaques. J Neurol Sci 158:47–52 (1998).
Lin, R. et al. Exposure to metal ions regulates mRNA levels of APP and BACE1 in PC12 cells: blockage by curcumin. Neurosci Lett 440:344–347 (2008).
Varela-Nallar, L. et al. Induction of cellular prion protein gene expression by copper in neurons. Am J Physiol Cell Physiol 290:C271–281 (2006).
Lin, R. et al. Exposure to metal ions regulates mRNA levels of APP and BACE1 in PC12 cells: blockage by curcumin. Neurosci Lett 440:344–347 (2008).
Andersen, C. L., Jensen, J. L. & Orntoft, T. F. Normalization of real-time quantitative reverse transcription-PCR data: a model-based variance estimation approach to identify genes suited for normalization, applied to bladder and colon cancer data sets. Cancer Res 64:5245–5250 (2004).
Pfaffl, M. W., Tichopad, A., Prgomet, C. & Neuvians, T. P. Determination of stable housekeeping genes, differentially regulated target genes and sample integrity: BestKeeper-Excel-based tool using pair-wise correlations. Biotechnol Lett 26:509–515 (2004).
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Kim, DK., Song, JW., Park, JD. et al. Copper induces the accumulation of amyloid-beta in the brain. Mol. Cell. Toxicol. 9, 57–66 (2013). https://doi.org/10.1007/s13273-013-0009-0
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DOI: https://doi.org/10.1007/s13273-013-0009-0