Savchuk O. Participation of proteasomal proteolysis following ischemic damage of the brain

The thesis is dedicated to study changes in proteasome activity in the nervous tissue, as well as the role of allelic polymorphisms of the genes coding for the proteasome subunits (PSMA6 and LMP2) in the pathogenesis of ischemic stroke using the real-time polymerase chain reaction method, also the experimental model of focal cerebral ischemia by monofilament occlusion of the middle cerebral artery (MCAО). The allelic polymorphism of the genes LMP2 (Arg60His) and PSMA6 (C-8G) (rs 1048990) was determined using the Real Time PCR method. For the first time, all three types of proteolytic activity of proteasome (trypsin-like, chymotrypsin-like and peptidylglutamyl 26 peptidhydrolase) were measured in the nerve tissue of rats and their changes in conditions of reproduction of ischemic stroke. The results of the study showed that changes in proteasome activity indicate predominance of immunoproteasomes compared to constitutional proteasome at 6 and 72 hours of reperfusion in brain tissues, as well as the predominance of constitutional proteasome at 24 hour reperfusion. For the first time complex investigations of cortical nerve cells and striatum of the brain on optical and electron microscopic levels have been carried out to study the dynamics of their structural changes after focal cerebral ischemia in rats. The correlation between changes in proteasome activity and changes in behavioral activity of animals in the dynamics of ischemic stroke was revealed. For the first time, the frequency of allelic polymorphism of genes encoding subunit constitutional and immunoproteasome in patients with ischemic stroke has been investigated. We found that in patients with a minor homozygotes allelic variant (His/His) of the subunit of the LMP2 immunoproteasome member and in patients with a minor homozygotes allelic variant of the PSMA6 (G/G) subunit, the ischemic stroke occurs at a significantly younger age compared with heterozygotes and major homozygotes polymorphism.