| Abstract [eng] |
Various heart diseases concomited with the death of cardiomyocytes is one of the major causes of death-rate. Regenerative stem cell therapy of damaged heart applying muscle-derived stem cells attains more and more attention. Patological environment in the damaged heart is major cause of death of newly transplanted muscle-derived stem cells. Therefore, everything increasing survival of transplanted myogenic cells is of research interest. This work has been designed to investigate role of stress protein Hsp70 in the regulation of intracellular systems responsible for the death or survival of primary myogenic cells. Rabbit muscle-derived stem cells were transfected with the plasmid carrying hsp70 gene. Various intracellular mechanisms responsible for the resistance of transfected cells have been investigated and compared with the regular non transfected primary myogenic cells. Our results show that Hsp70 protein protects rabbit muscle-derived stem cells from the toxic effect of compounds (naftazarin, hydrogen peroxide and sodium pruside) generating reactive oxigen species (ROS) and causing oxidative stress. Increased amount of intracellular Hsp70 protein converts transient/proapototic mode of action of ERK1,2 and JNK in regular primary myogenic cells to sustained/antiapoptotic action in transfected cells and significantly decreased total amount of JNK after the treatment with naftazatin. Transfected cells also showed sustained/anti-apoptotic mode of activation of transcription factor c-Jun. Hsp70 protein participates in the suppression of internal apoptotic pathway by stabilysing potential of inner mitochondrial membrane and pro-apoptotic protein Bax and suppressing an activation of initiating caspase-9 and executing caspase-3. Moreover, Hsp70 protein participates in the inhibition of unspecific activation of extrincic apoptotic pathway and of caspase-8. The study of intracellular changes, caused by the oxidative stress would not be cmplete if we would not mention the role of antioxidant molecules and enzymes. Increased amount of intracellular protein Hsp70 increased amount of total and reduced glutathione and activated glutathione S-transferase, catalase and superoxide dismutase. In summary we can conclude that constant overexpression of intracellular protein Hsp70 protects muscle-derived stem cells from the various toxic influences and is new and most progressive way of succsessful usage of primary myogenic cells in treatment of various diseases with regenerating stem cells transplantation. |
