Investigations on the Effects of Palmitate on Neuronal Cells

Many studies have demonstrated that increased levels of free fatty acids (FFAs) are associated with increased apoptosis in hepatocytes, podocytes, myocytes, and pancreatic islet cells. However, the effects of FAAs on neuronal cell function are not well characterized. In this study, mouse neuroblastoma cells from the Neuro-2a (N2a) cell line were treated with either bovine serum albumin (BSA) or different concentrations of BSA-conjugated palmitate (PA) and examined cell viability using MTT assay. Concentrations of PA at or above 200 μM in the growth media were associated with a decrease in cell viability. In order to examine whether N-acetylcysteine (NAC) or sodium phenylbutyrate (PB) affected the PA-induced decrease in cell viability, N2a cells were treated with PA in combination with either NAC or PB and cell viability was measured using MTT assay. Neither NAC in concentrations of up to 200 μM nor PB in concentrations of up to 1 mM was able to attenuate the PA-induced decrease in N2a viability. When viewed under a microscope PA treated cells exhibited increased irregularity in size and shape as compared to cells treated with BSA. In order to examine whether PA treatment affected insulin signaling in this cell line, N2a cells were treated with 200 μM PA for 24 hours followed by stimulation with 25 ng/mL insulin for 0, 5, or 10 minutes. Activation of AKT1 and GSK-3β was then analyzed by Western blot assay. Preliminary results suggested that while insulin-induced GSK-3β activation may not be affected by PA treatment, insulin-induced AKT1 activation appeared to be attenuated by PA treatment as compared to BSA-treated controls. These results remain to be confirmed and the mechanism of the PA-induced changes in viability and insulin signaling remain to be defined