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RNAi mediated silencing of cyclin-dependent kinases of G1 phase slows down the cell-cycle progression and reduces apoptosis

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Sierant M. , Piotrzkowska D. , Nawrot B.

Acta Neurobiologiae Experimentalis

2015

tom 75

nr 1

One of the hypotheses on the origin of Alzheimer's disease (AD) stems from a close relation between a re-activation of a cell-cycle in post-mitotic neurons and a neural cells death observed in pathologically affected parts of AD brains. In the normal, healthy brain almost all neural cells are terminally differentiated and "locked" in the GO phase of the cell-cycle. For these cells, the consequence of the re-entry to the cell-cycle is targeting them towards cellular divisions and turning on the apoptotic pathway. We used an RNA interference (RNAi) methodology in neural cells to switch-off genes for two cyclin- dependent kinases 4 and 6 (cdk4, cdk6), which control the activation of the initial steps of the cell-cycle. As a result, some evidences are delivered that silencing these genes, which are expressed during cell proliferation but inhibited at mature neurons, prevents the stimulation of apoptotic pathways in the neural cells cultured in a oxidative stress conditions and may have a neuroprotective effect. We demonstrate that down-regulation of genes important in the G1 phase of the cell-cycle may play the protective function on the neuronal cells, and can be considered as the promising approach for the potential gene therapy of neurodegenerative diseases.

Molecular mechanisms initiating amyloid beta-fibril formation in Alzheimer's disease

100%

Kirkitadze M. D. , Kowalska A.

2005

tom 52

nr 2

The deposition of aggregated amyloid β-protein (Aβ) in the human brain is a major lesion in Alzheimer’s disease (AD). The process of Aβ fibril formation is associated with a cascade of neuropathogenic events that induces brain neurodegeneration leading to the cognitive and behavioral decline characteristic of AD. Although a detailed knowledge of Aβ assembly is crucial for the development of new therapeutic approaches, our understanding of the molecular mechanisms underlying the initiation of Aβ fibril formation remains very incomplete. The genetic defects responsible for familial AD influence fibrillogenesis. In a majority of familial cases determined by amyloid precursor protein (APP) and presenilin (PS) mutations, a significant overproduction of Aβ and an increase in the Aβ42/Aβ40 ratio are observed. Recently, it was shown that the two main alloforms of Aβ have distinct biological activity and behaviour at the earliest stage of assembly. In vitro studies demonstrated that Aβ42 monomers, but not Aβ40, form initial and minimal structures (pentamer/hexamer units called paranuclei) that can oligomerize to larger forms. It is now apparent that Aβ oligomers and protofibrils are more neurotoxic than mature Aβ fibrils or amyloid plaques. The neurotoxicity of the prefibrillar aggregates appears to result from their ability to impair fundamental cellular processes by interacting with the cellular membrane, causing oxidative stress and increasing free Ca2+ that eventually lead to apoptotic cell death.

Molecular genetics of Alzheimer's disease: presenilin 1 gene analysis in a cohort of patients from the Poznan Region

100%

Kowalska A. , Wender M. , Florczak J. , Pruchnik-Wolinska D. , Modestowicz R. , Szczech J. , Rossa G. , Kozubski W.

2003

tom 44

nr 2