Adenosine Prevents Apoptosis in Neural Stem Cells by Down-Regulating Mst1 Expression

Background and Aim: Overproduction of free radicals during oxidativestress induces damage to key biomolecules and activates programmedcell death pathways. Apoptosis is regulated by the expression or activationof proapoptotic genes and proteins including mammalian sterile 20 likekinase 1 (Mst1). Neuronal cell death in the nervous system leads to anumber of neurodegenerative diseases. The aim of the present studywas to evaluate the neuroprotective effect of adenosine on inhibition ofapoptosis induced by hydrogen peroxide (H2O2) in bone marrow-derivedneural stem cells (B dNSCs), with focus on its regulatory effect on theexpression of Mst1, as a novel proapoptotic kinase.Methods: Bone marrow-derived stromal cells (BMSCs) isolated fromWistar rats and evaluated using CD90. To form B dNSCs, isolatedBMSCs cultured with NSC expansion medium containing DMEM/F12 supplemented with B27, bFGF, and EGF. Immunocytochemicalevaluation performed for Nestin as an NSC/progenitor cell marker.B dNSCs were exposed to adenosine at different doses (2, 4, 6, 8 and10 μM) for 48 hours followed by 125 μM H2O2 for 30 minutes. Thestudied groups included: N (untreated NSCs), NA (NSCs treated with 6μM adenosine), NH (NSCs treated with 125 μM H2O2), and NAH (NSCstreated with 6 μM adenosine and 125 μM H2O2). MTT assay was usedto determine an optimal concentration of adenosine. Using TUNEL assay,immunocytochemistry and Real-Time qPCR, the effect of adenosine onapoptosis and expression of Mst1 gene at the protein and mRNA levelwere evaluated in pretreated B dNSCs compared with control groups.Results: The B dNSCs from neurospheres expressed a high level ofnestin. Results of the MTT assay indicated 6 μM adenosine to be the mostprotective dose in terms of promotion of cell viability. Subsequent assaysusing this dosage indicated that apoptosis rate and Mst1 expression inB dNSCs pretreated by 6 μM adenosine were significantly decreasedcompared with the control groups.Conclusion: These findings suggest that adenosine protects B dNSCsagainst oxidative stress-induced cell death via down-regulating Mst1expression. Adenosine can cross the blood-brain barrier and thereforemay be considered as a suitable drug for the treatment of diseases of thenervous system caused by oxidative stress.

کلیدواژه ها:

Neural stem cells ، Adenosine ، Mst1 ، Apoptosis ، Oxidative stress