Faculty Bibliography

Protein misfolding, mitochondrial dysfunction and oxidative stress are common pathomechanisms that underlie neurodegenerative diseases. In prion disease, central to these processes is the post-translational transformation of cellular prion protein (PrPc) to the aberrant conformationally altered isoform; PrPSc. This can trigger oxidative reactions and impair mitochondrial function by increasing levels of peroxynitrite, causing damage through formation of hydroxyl radicals or via nitration of tyrosine residues on proteins. The 6 member Peroxiredoxin (Prdx) family of redox proteins are thought to be critical protectors against oxidative stress via reduction of H2O2, hydroperoxides and peroxynitrite. In our in vitro studies cellular metabolism of SK-N-SH human neuroblastoma cells was significantly decreased in the presence of H2O2 (oxidative stressor) or CoCl2 (cellular hypoxia), but was rescued by treatment with exogenous Prdx6, suggesting that its protective action is in part mediated through a direct action. We also show that CoCl2-induced apoptosis was significantly decreased by treatment with exogenous Prdx6. We proposed a redox regulator role for Prdx6 in regulating and maintaining cellular homeostasis via its ability to control ROS levels that could otherwise accelerate the emergence of prion-related neuropathology. To confirm this, we established prion disease in mice with and without astrocyte-specific antioxidant protein Prdx6, and demonstrated that expression of Prdx6 protein in Prdx6 Tg ME7-animals reduced severity of the behavioural deficit, decreased neuropathology and increased survival time compared to Prdx6 KO ME7-animals. We conclude that antioxidant Prdx6 attenuates prion-related neuropathology, and propose that augmentation of endogenous Prdx6 protein represents an attractive adjunct therapeutic approach for neurodegenerative diseases. Lay Summary Alzheimer's and prion diseases are characterized by accumulation and deposition of misfolded proteins. In prion disease parallel with loss of subsets of nerve cells is an increase in non-neuronal cells (astrocytes) that can impact on their homeostasis. These astrocytes produce peroxiredoxin-6 (Prdx6), a protective antioxidant protein constituent of specific pathways that are activated in response to the misfolding insult and could be highly beneficial to both neuronal and non-neuronal cells. We proposed a redox regulator role for Prdx6 in regulating and maintaining normal cell function via its ability to control the cell stressors, which would contribute to amelioration of prion pathology. To confirm this we generated diseased animals with and without Prdx6 protein. Upon onset of pathology we tested the animals behaviourally, and showed that there was improvement of behavioural deficit and rescue of survival in animals with Prdx6 (Prdx6 Tg) compared to animals without Prdx6 (Prdx6 KO). Neuropathology was attenuated in the brains of Prdx6KO animals compared to Prdx6 Tg animals with disease. Furthermore application of exogenous Prdx6 rescued toxicity due to a chemical inducer of oxidative stress and a chemical inducer of cellular hypoxia in cell culture. We contend that augmentation of endogenous Prdx6 protein represents an attractive adjunct therapeutic approach for acute and chronic degenerative diseases.

The paper concerns fast protons and neutrons from D-D fusion reactions in a Plasma-Focus-1000U facility. Measurements were performed with nuclear-track detectors arranged in "sandwiches" of an Al-foil and two PM-355 detectors separated by a polyethylene-plate. The Al-foil eliminated all primary deuterons, but was penetrable for fast fusion protons. The foil and first PM-355 detector were penetrable for fast neutrons, which were converted into recoil-protons in the polyethylene and recorded in the second PM-355 detector. The "sandwiches" were irradiated by discharges of comparable neutron-yields. Analyses of etched tracks and computer simulations of the fusion-products behavior in the detectors were performed.

Accumulation of ss-amyloid (Ass) in the brain is essential to Alzheimer inverted question marks disease (AD) pathogenesis. Carriers of the apolipoprotein E (APOE) inverted question mark4 allele demonstrate greatly increased AD risk and enhanced brain Ass deposition. In contrast, APOE inverted question mark2 allele carries show reduced AD risk, later age of disease onset, and lesser Ass accumulation. However, it remains elusive whether the apoE2 isoform exerts truly protective effect against Ass pathology or apoE2 plays deleterious role albeit less pronounced than the apoE4 isoform. Here, we characterized APPSW/PS1dE9/APOE inverted question mark2-TR (APP/E2) and APPSW/PS1dE9/APOE inverted question mark4-TR (APP/E4) mice, with targeted replacement (TR) of the murine Apoe for human inverted question mark2 or inverted question mark4 alleles, and used these models to investigate effects of pharmacological inhibition of the apoE/Ass interaction on Ass deposition and neuritic degeneration. APP/E2 and APP/E4 mice replicate differential effect of human apoE isoforms on Ass pathology with APP/E4 mice showing a several-fold greater load of Ass plaques, insoluble brain Ass levels, Ass oligomers, and density of neuritic plaques than APP/E2 mice. Furthermore, APP/E4 mice, but not APP/E2 mice, exhibit memory impairment on object recognition and radial arm maze tests. Between the age of 6 and 10 months APP/E2 and APP/E4 mice received treatment with Ass12-28P, a non-toxic, synthetic peptide homologous to the apoE binding motif within the Ass sequence, which competitively blocks the apoE/Ass interaction. In both lines, the treatment significantly reduced brain Ass accumulation, co-accumulation of apoE within Ass plaques, and neuritic degeneration, and prevented memory deficit in APP/E4 mice. These results indicate that both apoE2 and apoE4 isoforms contribute to Ass deposition and future therapies targeting the apoE/Ass interaction could produce favorable outcome in APOE inverted question mark2 and inverted question mark4 allele carriers.

Alzheimer's disease (AD) is associated with increased brain levels of beta-amyloid (Abeta) peptides, which readily self-aggregate into fibrils and oligomers that have particularly deleterious properties toward synapses of excitatory glutamatergic neurons. Here, we examined the neuroprotective effects of 1-methyl-1,2,3,4,-tetrahydroisoquinoline (1MeTIQ) against Abeta-induced loss of synaptic proteins in cultured primary hippocampal neurons. Exposure of mature primary hippocampal neurons to 10 muM synthetic Abeta1-40 over 72 h resulted in ~60 % reduction in the surface expression of NR1 subunit of the NMDA receptor (NMDAR), PSD-95, and synaptophysin, without causing neuronal death. Concomitant treatment with 500 muM of 1MeTIQ, a low-affinity NMDAR antagonist significantly ameliorated the loss of synaptic protein markers. The neuroprotective properties of 1MeTIQ were compared with those of MK-801, which at 0.5 muM concentration also prevented Abeta1-40-induced loss of synaptic proteins in primary neuronal cultures. Furthermore, we provide novel evidence demonstrating effectiveness of 1MeTIQ in reducing the level of reactive oxygen species (ROS) in primary neuronal culture system. As oxidative stress contributes importantly to neurodegeneration in AD, 1MeTIQ may provide a dual neuroproctective effect in AD both as a NMDARs antagonist and ROS formation inhibitor. 1MeTIQ occurs endogenously at low concentrations in the brain and its synthetic form readily penetrates the blood-brain barrier after the systemic administration. Our results highlight a possibility of the application of 1MeTIQ as a neuroprotective agent in AD-related neurodegeneration.

Objective: Proteolytic cleavage of the amyloid precursor protein (APP) generates beta-amyloid (Abeta) peptides. Prolonged accumulation of Abeta in the brain underlies the pathogenesis of Alzheimer's disease (AD) and is regarded as a principal target for development of disease-modifying therapeutics. Methods: Using CHO APP751SW cells we identified and characterized effects of 2-[(pyridine-2-ylmethyl)-amino]-phenol (2-PMAP) on APP steady-state level and Abeta production. Outcomes of 2-PMAP treatment on Abeta accumulation and associated memory deficit were studied in APPSW /PS1dE9 AD transgenic model mice. Results: In CHO APP751SW cells, 2-PMAP in a dose-response manner lowered the steady-state APP level and inhibited Abetax-40 and Abetax-42 production with minimum effective concentration