miR‐34a/BCL‐2 signaling axis contributes to apoptosis in MPP(+)‐induced SH‐SY5Y cells

BACKGROUND: Parkinson's disease (PD) is a neurodegenerative disorder which mainly affects the elderly population of various societies. The main hallmark of this disease is the loss of dopaminergic (DA) neurons. So far, numerous studies have implied the role of microRNAs in fine‐tuning cellular processes including apoptosis. Studies have also shown that miR‐34a is mainly involved in age‐related disorders including Alzheimer's disease, and its expression is usually higher in the brain sample patients. Furthermore, the key role of miR‐34a in the expression of BCL‐2, and thus, in vitro and in vivo apoptosis has been revealed. miR‐34a/BCL‐2 axis is therefore of critical importance in inducing or inhibiting apoptosis. METHODS: In this study, human SH‐SY5Y cells were treated with MPP+ and the expression of miR‐34a and BCL2 was assessed. RESULTS: Our results also showed that treating human SH‐SY5Y neuronal cells using MPP(+) to induce oxidative stress and apoptosis led to the upregulation of miR‐34a, as compared to the nontreated control group. Moreover, evaluating the expression level of BCL‐2 in these cells indicated a contradictory pattern, as compared with miR‐34a. It was also revealed that the expression of BCL‐2 was significantly decreased in MPP(+)‐treated cells, thereby confirming previous studies regarding a new concept. In this study, we show that miR‐34a/BCL‐2 axis is directly correlated with oxidative stress and apoptosis in SH‐SY5Y cells as a model of DA neurons. CONCLUSION: miR‐34a and its target gene, BCL‐2, play a possible role in the induction of apoptosis in DA neurons, and therefore, they have a potential role in the pathogenesis of PD. Consequently, the therapeutic potential of miR‐34a could be considered in order to inhibit the progression of PD.