The effect of OTK18 upregulation in U937 cells on neuronal survival.

The intent of this study was to characterize the effect OTK18 upregulation in monocytic cells had on neuronal survival. The human monocytic cell line, U937, was differentiated into macrophages or left as an undifferentiated monocyte. These cells were transfected with a plasmid containing the enhanced green fluorescent protein and OTK18 (pEGFP-OTK18) or an empty control vector (pEGFP-N3). The supernatants from the transfected U937 cells were used to culture rat neuronal cells (PC12). A live/dead assay was performed to determine the effect of culturing on cell survival. The protein levels of the neurotoxin, tumor necrosis factor alpha (TNF-alpha), and the neurotrophin, neurotrophin three (NT3), were determined by enzyme linked immunosorbent assay. The results of the live/dead assay showed differential cell survival between conditions with pEGFP-OTK18 when compared to the control empty vector. Quantitative real-time polymerase chain reaction assays demonstrated that OTK18 had an increased expression level when compared to the control. Lastly, NT3 protein levels were upregulated in treated cells with increased OTK18 expression, suggesting that OTK18 may play a role in neurotrophin production and consequently support neuronal survival.