Acta Pharmacologica Sinica (2009) 30: 388-395; doi: 10.1038/aps.2009.25

Aim: We have investigated the effects of lysophosphatidylcholine (LPC), a product of lipid peroxidation, on Aβ_1?2-induced SH-SY5Y cell apoptosis.

Methods: The viability of cultured SH-SY5Y cells was measured using a CCK-8 kit. Apoptosis was determined by Chip-based flow cytometric assay. The mRNA transcription of Bcl-2, Bax, and caspase-3 were detected by using reverse transcription and real-time quantitative PCR and the protein levels of Bax and caspase-3 were analyzed by Western blotting. The cytosolic calcium concentration of SH-SY5Y cells was tested by calcium influx assay. G 2A expression in SH-SY5Y cells was silenced by small interfering RNA.    

Results: Long-term exposure of SH-SY5Y cells to LPC augmented the neurotoxicity of Aβ_1?2. Furthermore, after LPC treatment, the Bax/Bcl-x_L ratio and the expression levels, as well as the activity of caspase-3 were, elevated, whereas the expression level of TRAF1 was reduced. Because LPC was reported to be a specific ligand for the orphan G-protein coupled receptor, G 2A , we investigated LPC-mediated changes in calcium levels in SH-SY5Y cells. Our results demonstrated that LPC can enhance the Aβ_1?2-induced elevation of intracellular calcium. Interestingly, Aβ_1?2 significantly increased the expression of G 2A in SH-SY5Y cells, whereas knockdown of G 2A using siRNA reduced the effects of LPC on Aβ_1?2-induced neurotoxicity.

Conclusion: The effects of LPC on Aβ_1?2-induced apoptosis may occur through the signal pathways of the orphan G-protein coupled receptor.

Keywords:  amyloid beta (1?2) peptide; lysophosphatidylcholine; neuronal apoptosis