Paraoxon-induced protein expression changes to SH-SY5Y cells.

SH-SY5Y neuroblastoma cells were examined to determine changes in protein expression following exposure to the organophosphate paraoxon (O,O-diethyl-p-nitrophenoxy phosphate). Exposure of SH-SY5Y cells to paraoxon (20 μM) for 48 h showed no significant change in cell viability as established using an MTT assay. Protein expression changes from the paraoxon-treated SH-SY5Y cells were determined using a comparative, subproteome approach by fractionation into cytosolic, membrane, nuclear, and cytoskeletal fractions. The fractionated proteins were separated by 2D-PAGE, identified by MALDI-TOF mass spectrometry, and expression changes determined by densitometry. Over 400 proteins were separated from the four fractions, and 16 proteins were identified with altered expression ≥1.3-fold including heat shock protein 90 (-1.3-fold), heterogeneous nuclear ribonucleoprotein C (+2.8-fold), and H(+) transporting ATP synthase beta chain (-3.1-fold). Western blot analysis conducted on total protein isolates confirmed the expression changes in these three proteins.