Kyrychenko V. RNA-interference of ubiquitin-dependent proteasome proteolysis components in cardiomyocytes culture and heart tissue

Biochemical and morphological consequences of ubiquitin and proteasome b7 subunit knock-down in cardiomyocytes culture in control and after anoxia-reoxygenation and in heart tissue after ischemia-reperfusion were investigated. It was shown that ubiquitin downregulation leads to cardiomyocytes viability enhancement and prevent from necrotic cell death after ischemia-reperfusion modeling. Development of autophagic processes in cardiomyocytes in culture and rats' heart after ubiquitin knock-down were estimated. We established that proteasome b7 subunit knock-down downregulates peptidyl-glutamyl-peptide hydrolyzing proteasome activity as well as b1 proteasome subunit mRNA expression (which is responcible for this activity) in cardiomyocytes. Only one proteasome b7 subunit mRNA downregulation leads to activation of autophagy in cells. Autophagic cells amount grows up after additional cardiomyocytes damage by anoxia-reoxygenation modelling. b7 subunit knock-down causes signs of endoplasmic reticulum stress and autophagy development in myocard also. It was estimated that maleimide derivates, whish can modulate proteasome activity in vitro, lead to cardiomyocytes viability decreasing. But they protect cardiomyocytes in culture from damaging influence of anoxia-reoxygenation.