ISBN: 978-605-63544-8-9OP-16Stress Condition Induced by H2O2 Differentially Changes Gene Expression Levels of CaMKIIIsoforms in Mesenchymal Stem CellsTuğba ŞAN1, Pınar AKAN1, Mehmet Emin GÜNEŞ21Dokuz Eylul University, Institute of Health Sciences, Department of Neuroscience, İzmir, Turkey2İzmir Tepecik Training and Research Hospital, Department of Obstetrics and Gynecology, Izmir,TurkeyCalcium/Calmodulin Dependent Protein Kinase 2 (CAMKII) is one of the main effector enzymesinvolved in calcium signaling in eukaryotic cells and it has a key role on the learning process of theneuronal tissue. The inhibition of calcium / calmodulin dependent protein kinase 2 can preventapoptosis in neuronal cells and may also control stem cell proliferation. The isoforms of CaMKII hasdifferent calcium trapping kinetics and affinity for other protein bindings. In this study, we aim toinvestigate the changes on the level of gene expressions of CaMKII isoforms (alpha, beta, gama, delta)under the stress conditions induced by Hydrogen peroxide (H2O2) in mesenchymal stem cells.Mesenchymal stem cells were obtained from human umbilical cord by explant method. CaMKIIenzyme isoforms levels were determined by RT-qPCR under H2O2 induced stress conditions. Effectsof application of KN-93 which is a CaMKII inhibitor on stem cell viability and proliferation weredetermined by MTT and MTS tests.It was shown that the application of H2O2 (1mM) for 30 minutes to generate oxidative stressdecreased the cell viability ~40 – 50% in proportion to control group. In WJ-MSCs without anyapplication, there was no statistically significant difference between the gene expression levels ofalpha, beta, gamma and delta isoforms (p> 0.05). After H2O2 (1mM) treatment gene expression levelof CaMKII Beta isoform increased 7.7 fold compared to the control group but interestingly geneexpression level of CaMKII Delta isoform significantly reduced (p In conclusion, according to our literature review, the relationship between CaMKII isoforms andmesenchymal stem cell viability and their changes in stress conditions induced by H2O2 were firstlydemonstrated by this study. The data which were obtained from our study may provide afundamental ground to understand response mechanism of MSCs to the stress conditions and todevelop targeted stem cell treatment strategies.Keywords: Mesenchymal Stem Cell, Wharton’s Jelly, Oxidative Stress, CaMKII, KN-93, KN- 92