Oxidative neuropathology and putative chemical entities for Alzheimer's disease: neuroprotective effects of salen-manganese catalytic anti-oxidants.

Considerable evidence exists that the brains of individuals with Alzheimer's disease are subject to elevated levels of oxidative stress, particularly in regions exhibiting pathological damage. A major contributor to this oxidative stress appears to be the inflammatory process. Activation of rodent microglial cells by LPS or beta-amyloid peptide results in a marked up-regulation of inducible nitric oxide synthase (iNOS) and corresponding nitric oxide (NO) production.

Ultrastructural and behavioural changes precede amyloid deposition in a transgenic model of Alzheimer's disease.

We describe the thorough characterisation of a new transgenic mouse line overexpressing the 695-amino acid isoform of human amyloid precursor protein harbouring the Swedish double familial Alzheimer's disease mutation. This line, referred to as TAS10, exhibits neuropathological features and cognitive deficits that are closely correlated to the accumulation of Abeta in their brain and that are reminiscent of those observed in AD. Data on the TAS10 line are presented at five time points: 2, 6, 12, 18 and 24 months in a longitudinal study.

Apolipoprotein E (apoE) uptake and distribution in mammalian cell lines is dependent upon source of apoE and can be monitored in living cells.

As part of investigations of the cellular uptake of apolipoprotein E (apoE) relevant to Alzheimer's disease we have found that different preparations of apoE are handled differently by cells expressing the LDL-receptor. Comparing recombinant, cellular and native apoE, complexed with different preparations of lipid we find that only cellular and native apoE enter a vesicular compartment. Some, but not all of these apoE containing vesicles are lysosomes.

Presenilin 1 independently regulates beta-catenin stability and transcriptional activity.

Presenilin 1 (PS1) regulates beta-catenin stability; however, published data regarding the direction of the effect are contradictory. We examined the effects of wild-type and mutant forms of PS1 on the membrane, cytoplasmic, nuclear, and signaling pools of endogenous and exogenous beta-catenin by immunofluorescence microscopy, subcellular fractionation, and in a transcription assay. We found that PS1 destabilizes the cytoplasmic and nuclear pools of beta-catenin when stabilized by Wnt or Dvl but not when stabilized at lower levels of the Wnt pathway.

Oxidative signalling and inflammatory pathways in Alzheimer's disease.

It is well established that inflammation and oxidative stress are key components of the pathology of Alzheimer's disease (AD), but how early in the pathological cascade these processes are involved or which specific molecular components are key, has not been fully elucidated. This paper describes the pharmacological approach to understand the molecular components of inflammation and oxidative stress on the activation of microglial cells and neuronal cell viability. We have shown that activation of microglia with the 42-amino-acid form of the beta-amyloid peptide (A beta 42) activates the production of cyclooxygenase-2, the inducible form of nitric oxide synthase and tumour necrosis factor-alpha and there appears to be little interactive feedback between these three mediators.