Taurine protection of PC12 cells against endoplasmic reticulum stress induced by oxidative stress

Abstract

Background

Taurine is a free amino acid present in high concentrations in a variety of organs of mammalians. As an antioxidant, taurine has been found to protect cells against oxidative stress, but the underlying mechanism is still unclear.

Methods

In this report, we present evidence to support the conclusion that taurine exerts a protective function against endoplasmic reticulum (ER) stress induced by H ₂O ₂ in PC 12 cells. Oxidative stress was introduced by exposure of PC 12 cells to 250 uM H ₂O ₂ for 4 hours.

Results

It was found that the cell viability of PC 12 cells decreased with an increase of H ₂O ₂ concentration ranging from approximately 76% cell viability at 100 uM H ₂O ₂ down to 18% at 500 uM H ₂O ₂. At 250 uM H ₂O ₂, cell viability was restored to 80% by taurine at 25 mM. Furthermore, H ₂O ₂ treatment also caused a marked reduction in the expression of Bcl-2 while no significant change of Bax was observed. Treatment with taurine restored the reduced expression of Bcl-2 close to the control level without any obvious effect on Bax. Furthermore, taurine was also found to suppress up-regulation of GRP78, GADD153/CHOP and Bim induced by H ₂O ₂, suggesting that taurine may also exert a protective function against oxidative stress by reducing the ER stress.

Conclusion

In summary, taurine was shown to protect PC12 cells against oxidative stress induced by H ₂O ₂. ER stress was induced by oxidative stress and can be suppressed by taurine.