XBP1S protects cells from ER stress-induced apoptosis through Erk1/2 signaling pathway involving CHOP
Authors: Feng-Jin Guo
Suxin Luo
Chuanju Liu
Wenjun Zhao
Yanna Liu
Jinghua Zhou
Xiangzhu Li
Journal: Histochemistry and Cell Biology (2012)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: UPR; XBP1S; ER stress; apoptosis; cell proliferation
Affiliations: Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing 400016, China. 

Abstract:  The mammalian unfolded protein response (UPR) protects the cell against the stress of misfolded proteins in the endoplasmic reticulum (ER), and the transcription factor X-box binding protein 1 spliced (XBP1S), a regulator of the UPR, is known to be important for ER stress (ERS)-mediated apoptosis and cell growth, but the molecular mechanism underlying these processes remains unexplored. Here, we report that knockdown of XBP1S by an siRNA silencing approach increased the expression of ERS-associated molecules. The overexpression of XBP1S stimulated, whereas its knockdown inhibited, cell proliferation in chondrocytes and chondrosarcoma cells; in addition, overexpression of XBP1S inhibited, while its repression enhanced, ERS-mediated apoptosis in chondrocytes and chondrosarcoma cells. Furthermore, XBP1S-mediated inhibition of apoptosis in response to ERS is through the Erk1/2 signaling pathway and down-regulation CHOP transcription factor. CHOP is one of the key downstream molecules known to be involved in ERS-mediated apoptosis. Collectively, these findings reveal a novel critical role of XBP1S in ERS-mediated apoptosis and the molecular mechanisms involved. 

Retracted: Yes

PubPeer comments:
 XBP1S protects cells from ER stress-induced apoptosis through Erk1 2 signaling pathway involving CHOP. Guo FJ, Liu Y, Zhou J, Luo S, Zhao W, Li X, Liu C. Histochem Cell Biol. 2012 Sep;138(3):447-60. doi: 10.1007 s00418-012-0967-7. Epub 2012 Jun 6. PMID: 22669460 XBP1U inhibits the XBP1S-mediated upregulation of the iNOS gene expression in mammalian ER stress response. Guo F, Lin EA, Liu P, Lin J, Liu C. Cell Signal. 2010 Dec;22(12):1818-28. doi: 10.1016 j.cellsig.2010.07.006. Epub 2010 Jul 15. PMID: 20637858 ![file] , 
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 2021 retraction. https: link.springer.com article 10.1007 s00418-021-02000-0 Retraction to: Histochem Cell Biol (2012) 138:447u2013460 https: doi.org 10.1007 s00418-012-0967-7 The Editor-in-Chief has retracted this article by Guo et al. (2012) because panels a, b and c of Fig. 1C appear to have been previously published (Guo et al. 2010) as Fig. 4A, XBP1U panel and XPB1S panel and Fig. 4B XPB1S panel respectively. Additionally, panel d of Fig. 5A appears to overlap with the u03b2-actin panel of Fig. 1D in Li et al. (2012). The Editor-in-Chief has therefore concluded that the data reported in this article are unreliable. Feng-Jin Guo disagrees with this retraction. The other authors have not responded to any correspondence regarding this retraction. References Guo Feng-Jin, Lin EA, Liu P, Lin J, Liu C (2010) XBP1U inhibits the XBP1S-mediated upregulation of the iNOS gene expression in mammalian ER stress response. Cell Signal 22(12):1818u20131828. https: doi.org 10.1016 j.cellsig.2010.07.006 Li X, Zhu H, Huang H et al (2012) Study on the effect of IRE1u03b1 on cell growth and apoptosis via modulation PLK1 in ER stress response. Mol Cell Biochem 365:99u2013108. https: doi.org 10.1007 s11010-012-1248-4 ,