Dan Hong1, Yong-Ping Bai2, Hai-Chao Gao1, Xiang Wang1, Ling-Fang Li1, Guo-Gang Zhang3, Chang-Ping Hu4. 1. Department of Cardiovascular Medicine, Xiangya Hospital, Central South University, Xiangya Road 87#, Changsha 410008, China. 2. Department of Geriatric Medicine, Xiangya Hospital, Central South University, Changsha 410008, China. 3. Department of Cardiovascular Medicine, Xiangya Hospital, Central South University, Xiangya Road 87#, Changsha 410008, China. Electronic address: xyzgg2006@sina.com. 4. Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, Changsha 410008, China. Electronic address: huchangping2001@yahoo.com.cn.
Abstract
OBJECTIVE: To investigate the effect of lectin-like ox-LDL receptor-1 (LOX-1) on oxidized low-density lipoprotein (ox-LDL)-induced apoptosis and the involvement of the endoplasmic reticulum (ER) stress response pathway. METHODS AND RESULTS: Human umbilical vein endothelial cells were treated with 50, 100, or 200 μg/ml ox-LDL and cultured for 12, 24, or 48 h for concentration- and time-dependent studies. Cells were transfected with LOX-1 or Nox-4 shRNAs, and target proteins were inhibited with the corresponding antibodies for mechanistic studies. Active proteins and mRNAs were analyzed by Western blotting and RT-PCR, respectively. Cell apoptosis was analyzed by Annexin and Hoechst staining assays. Ox-LDL induced both apoptosis and protein expression of LOX-1 and Nox-4 through activation of ER stress sensors IRE1 and PERK, and nuclear translocation of ATF6 and their subsequent pathways were indicated by JNK, eukaryotic initiation factor 2 phosphorylation, XBP-1, and chaperone GRP78 expression; up-regulation of proapoptotic proteins CHOP and Bcl-2; and caspase-12 activity. LOX-1 gene silencing and treatment with an anti-LOX-1 antibody attenuated the effects of ox-LDL. Pretreatment with irestatin 9389, salubrinal, or AEBSF also blocked ox-LDL-induced expression of CHOP and Bcl-2 and activation of caspase-12 activity, leading to an attenuation of endothelial cell apoptosis. Furthermore, Nox-4 siRNA attenuated the up-regulated expression of GRP78, PERK, IRE1, and XBP-1 to reduce ox-LDL-induced endothelial cell apoptosis. CONCLUSIONS: LOX-1 plays a critical role in ox-LDL-induced endothelial cell apoptosis via the ER stress pathway.
OBJECTIVE: To investigate the effect of lectin-like ox-LDL receptor-1 (LOX-1) on oxidized low-density lipoprotein (ox-LDL)-induced apoptosis and the involvement of the endoplasmic reticulum (ER) stress response pathway. METHODS AND RESULTS:Human umbilical vein endothelial cells were treated with 50, 100, or 200 μg/ml ox-LDL and cultured for 12, 24, or 48 h for concentration- and time-dependent studies. Cells were transfected with LOX-1 or Nox-4 shRNAs, and target proteins were inhibited with the corresponding antibodies for mechanistic studies. Active proteins and mRNAs were analyzed by Western blotting and RT-PCR, respectively. Cell apoptosis was analyzed by Annexin and Hoechst staining assays. Ox-LDL induced both apoptosis and protein expression of LOX-1 and Nox-4 through activation of ER stress sensors IRE1 and PERK, and nuclear translocation of ATF6 and their subsequent pathways were indicated by JNK, eukaryotic initiation factor 2 phosphorylation, XBP-1, and chaperone GRP78 expression; up-regulation of proapoptotic proteins CHOP and Bcl-2; and caspase-12 activity. LOX-1 gene silencing and treatment with an anti-LOX-1 antibody attenuated the effects of ox-LDL. Pretreatment with irestatin 9389, salubrinal, or AEBSF also blocked ox-LDL-induced expression of CHOP and Bcl-2 and activation of caspase-12 activity, leading to an attenuation of endothelial cell apoptosis. Furthermore, Nox-4 siRNA attenuated the up-regulated expression of GRP78, PERK, IRE1, and XBP-1 to reduce ox-LDL-induced endothelial cell apoptosis. CONCLUSIONS:LOX-1 plays a critical role in ox-LDL-induced endothelial cell apoptosis via the ER stress pathway.
Authors: Sahra Bodo; Cécile Campagne; Tin Htwe Thin; Daniel S Higginson; H Alberto Vargas; Guoqiang Hua; John D Fuller; Ellen Ackerstaff; James Russell; Zhigang Zhang; Stefan Klingler; HyungJoon Cho; Matthew G Kaag; Yousef Mazaheri; Andreas Rimner; Katia Manova-Todorova; Boris Epel; Joan Zatcky; Cristian R Cleary; Shyam S Rao; Yoshiya Yamada; Michael J Zelefsky; Howard J Halpern; Jason A Koutcher; Carlos Cordon-Cardo; Carlo Greco; Adriana Haimovitz-Friedman; Evis Sala; Simon N Powell; Richard Kolesnick; Zvi Fuks Journal: J Clin Invest Date: 2019-01-14 Impact factor: 14.808