Abstract A18: Geranylgeranoic acid (GGA) induced autophagic cell death through induction of unfolded protein response (UPR) and suppression of mTOR signaling pathway

Author(s):  
Chieko Iwao ◽  
Yoshihiro Shidoji
2015 ◽  
Vol 36 (6) ◽  
pp. 2403-2417 ◽  
Author(s):  
Shaoying Li ◽  
Liang Guo ◽  
Pin Qian ◽  
Yunfeng Zhao ◽  
Ao Liu ◽  
...  

Background: Alveolar epithelial cell death plays a critical role in the pathogenesis of lipopolysaccharide (LPS)-induced acute lung injury. Increased autophagy has a dual effect on cell survival. However, it is not known whether autophagy promotes death or survival in human alveolar epithelial cells exposed to LPS. Methods: Genetic and pharmacological approaches were used to evaluate the effect of autophagy on A549 cell viability upon LPS exposure. The endoplasmic reticulum (ER) stress and unfolded protein response (UPR) pathways were examined with immunoblotting studies to further explore underlying mechanisms. Results: Treatment with LPS (50 µg/ml) led to autophagy activation and decreased cell viability in A549 cells. Blocking autophagy via short interfering RNA or inhibitor significantly decreased, whereas rapamycin increased, the LPS-induced effect on viability. ER stress was activated in LPS-stimulated A549 cells, and ER stress inhibitor reduced LPS-induced autophagy. LPS activated only the PERK pathway and had rarely effect on the ATF6 and IRE1 branches of the UPR in A549 cells. Moreover, the knockdown of PERK and ATF4 attenuated LPS-induced autophagy and promoted cell survival. Conclusion: In human alveolar epithelial A549 cells, LPS induces autophagic cell death that depends on the activation of the PERK branch of the UPR upon ER stress.


2010 ◽  
Vol 31 (8) ◽  
pp. 1424-1433 ◽  
Author(s):  
Y. Suh ◽  
F. Afaq ◽  
N. Khan ◽  
J. J. Johnson ◽  
F. H. Khusro ◽  
...  

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