Marcelo A Chacón

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The activation of the canonical Wnt signaling pathway protects hippocampal neurons against the toxicity of Alzheimer's amyloid-beta-peptide (Abeta), however, the role played by the Wnt receptors Frizzleds, has not been studied. We report here that Frizzled-1 mediates the activation of the canonical Wnt/beta-catenin pathway by Wnt3a in PC12 cells. In(More)
It is generally accepted that human Alzheimer's disease (AD) neuropathology markers are completely absent in rodent brains. We report here that an aged wild-type South American rodent, Octodon degu, expresses neuronal beta-amyloid precursor protein (beta-APP695) displaying both intracellular and extracellular deposits of amyloid-beta-peptide (Abeta),(More)
Alzheimer's disease (AD) is a progressive dementia paralleled by selective neuronal death, which is probably caused by the cytotoxic effects of the amyloid-beta peptide (Abeta). We have observed that Abeta-dependent neurotoxicity induces a loss of function of Wnt signaling components and that activation of this signaling cascade prevent such cytotoxic(More)
Previous studies have demonstrated that acetylcholinesterase (AChE) promotes the assembly of amyloid-beta-peptides into neurotoxic amyloid fibrils and is toxic for chick retina neuronal cultures and neuroblastoma cells. Moreover, AChE is present in senile plaques in Alzheimer's disease (AD) brains. Here we have studied the effect of AChE on astrocytes and(More)
Proteins of the major histocompatibility complex class I (MHCI) are known for their role in the vertebrate adaptive immune response, and are required for normal postnatal brain development and plasticity. However, it remains unknown if MHCI proteins are present in the mammalian brain before birth. Here, we show that MHCI proteins are widely expressed in the(More)
Neuropathological changes generated by human amyloid-beta peptide (Abeta) fibrils and Abeta-acetylcholinesterase (Abeta-AChE) complexes were compared in rat hippocampus in vivo. Results showed that Abeta-AChE complexes trigger a more dramatic response in situ than Abeta fibrils alone as characterized by the following features observed 8 weeks after(More)
The amyloid precursor protein (APP) contains a Cu binding domain (CuBD) localized between amino acids 135 and 156 (APP135-156), which can reduce Cu2+ to Cu1+ in vitro. The physiological function of this APP domain has not yet being established; nevertheless several studies support the notion that the CuBD of APP is involved in Cu homeostasis. We used APP(More)
A 13-year-old boy developed cramps and myoglobinuria following exertion. Mitochondrial preparations from a skeletal muscle biopsy were deficient in carnitine palmitoyltransferase (CPT) activity when assayed by the hydroxamate and kinetic assays. The patient's fibroblasts were also deficient when assayed by the hydroxamate and kinetic assays, but not when(More)
Human prion protein fragments (PrP60-67 or PrP59-91) prevented and reversed the inhibition elicited by 5 micro m copper on the P2X4 receptor expressed in Xenopus laevis oocytes. A 60-s pre-application of 5 micro m copper caused a 69.2 +/- 2.6% inhibition of the 10 micro m adenosine triphosphate (ATP)-evoked currents, an effect that was prevented by mixing 5(More)
Prion diseases are fatal neurodegenerative disorders associated with the conversion of the cellular prion protein (PrPC) into a pathologic isoform. Although the physiological function of PrPC remains unknown, evidence relates PrPC to copper metabolism and oxidative stress as suggested by its copper-binding properties in the N-terminal octapeptide repeat(More)