Alzheimer’s Disease (AD) is the most severe dementia that progressively and irreversibly impairs synaptic function and cognition of millions of people around the world. Despite many years of research on Aβ peptides toxicity as well as on molecular processes that are involved in AD pathology, the pathogenesis of the disease is still not fully elucidated. The aim of this thesis was to investigate mRNA levels of secretases, NAD+-dependent enzymes (PARPs and SIRTs), sphingosine metabolism enzymes as well as pro- and anti-apoptotic proteins in experimental models of AD. In addition, the effect of poli(ADP-ribose) polymerase inhibitor (PJ-34) and S1P receptors modulator (FTY720) on the mRNA levels of the above mentioned genes was investigated. In present study the cellular model of Aβ toxicity (pheochromocytoma, PC12) was used. The toxicity was evoked by extracellular oligomers of Aβ1-42 (Aβo) or by transfection with the APP gene. Additionally the effect of PJ-34 was examined under Aβo1-42 toxicity. Non-transfected PC12 cells were also treated with ASNo (α-synuclein oligomers). The mRNA levels of genes examined in cellular model were compared with data obtained in transgenic FVB/APP+/- mice with the London (Val717Ile) mutation of the APP gene. The effect of intraperitoneal administration of FTY720 on APP+ brain mRNA levels of abovementioned genes was also examined. The results of the following work showed important role of the nuclear PARP1 enzyme in the regulation of mRNA levels of genes involved in APP metabolism during toxicity induced by Aβo. At the same time, the neuroprotective effect of inhibition of PARP1 activity was expressed by increase of mRNA level of the gene encoding pro-survival sirtuin 1. Moreover, a reduction in Sphk2 mRNA level was also observed in both cell lines transfected with the APP gene and in the brains of 12-month-old APP+ mice. Similarly, reduction of Sphk2 mRNA and SPHK1/2 activity was noted in ASNo-treated cells. Furthermore, the use of S1P receptor modulator (FTY720, fingolimod) has been shown to increase ceramide kinase gene expression (the enzyme responsible for phosphorylation of ceramide to its pro-survival form - ceramide-1-phosphate) in the brains of APP+ mice. It has also been shown that FTY720 can act as a neuroprotective agent by increasing the mRNA level of gene encoding the pro-survival Bcl-2 protein, which regulates mitochondrial apoptosis pathway. The observed alterations of gene expression updates the state of knowledge regarding the role of PARPs, SIRTuin and bioactive sphingolipids in the pathology of AD and may be helpful in developing new neuroprotective strategies.
Operational Program Digital Poland, 2014-2020, Measure 2.3: Digital accessibility and usefulness of public sector information; funds from the European Regional Development Fund and national co-financing from the state budget.
Feb 18, 2020
Oct 31, 2019
Pluta, Ryszard Kida, Elżbieta Lossinsky, AS. Wiśniewski, HM. Mossakowski, Mirosław Jan (1929 - 2001)
Łałowski, Maciej M.