title: Anti-dsDNA antibodies induce inflammation via endoplasmic reticulum stress in human mesangial cells.
abstract: BACKGROUND
  Anti-dsDNA antibodies play an important role in the pathogenesis of lupus nephritis (LN). Endoplasmic reticulum (ER) stress is a physical reaction under stressful condition and can cause inflammation when stimulation is sustained. This study investigated the roles of ER stress in anti-dsDNA antibody-induced inflammation response in human mesangial cells (HMCs).
  
  
  METHODS
  Anti-dsDNA antibodies isolated from LN patients were used to stimulate HMCs. The expression of GRP78, PERK, p-PERK, p-eIF2α, ATF4, p-IRE1α, ATF6 and CHOP in HMCs was measured by western blot. NF-κB activation was detected by examining nuclear translocation of NF-κB p65. The expression and production of IL-1β, TNF-α and MCP-1 were examined by qPCR and ELISA.
  
  
  RESULTS
  Flow cytometry and cellular ELISA showed that anti-dsDNA antibodies can bind to HMCs. The binding was not inhibited by blockage of Fc receptor. Anti-dsDNA antibody stimulation significantly enhanced the expression of GRP78, p-PERK, p-eIF2α and ATF4 in HMCs. However, no significant increase in the expression of p-IRE1α and ATF6 was found. In addition, anti-dsDNA antibodies also significantly increased the activation of NF-κB and upregulated the expression of IL-1β, TNF-α and MCP-1, which were suppressed by pretreatment of HMCs with chemical ER stress inhibitor 4-PBA. Transfection of specific ATF4 siRNA also significantly reduced the activation of NF-κB and expression of proinflammatory cytokines.
  
  
  CONCLUSIONS
  Anti-dsDNA antibodies induce NF-κB activation and inflammation in HMCs via PERK-eIF2α-ATF4 ER stress pathway.
authors.affiliation: Department of Rheumatology, First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan Road II, Guangzhou, 510080, China. sysuzhanghui@163.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Rheumatology, First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan Road II, Guangzhou, 510080, China. zhaochunmei2@163.com.|Department of Rheumatology, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan South Road, Urumqi, 830054, China. zhaochunmei2@163.com.
authors.forename: Chunmei
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Department of Rheumatology, First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan Road II, Guangzhou, 510080, China. wangshuang_1115@163.com.
authors.forename: Shuang
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Pediatrics, First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan Road II, Guangzhou, 510080, China. zsuhyf@163.com.
authors.forename: Yuefang
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Rheumatology, First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan Road II, Guangzhou, 510080, China. wangyue_0814@163.com.
authors.forename: Hongyue
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Rheumatology, First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan Road II, Guangzhou, 510080, China. sysujijunzhao@163.com.
authors.forename: Jijun
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Rheumatology, First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan Road II, Guangzhou, 510080, China. zsuyns@163.com.
authors.forename: Niansheng
authors.initials: N
authors.lastname: Yang
mesh_terms: D051702:Activating Transcription Factor 6 / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000974:Antibodies, Antinuclear / Q000494:pharmacology; D003710:Demography; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D004722:Endoribonucleases / Q000378:metabolism; D005260:Female; D006801:Humans; D007249:Inflammation / Q000473:pathology*; D008297:Male; D050527:Mesangial Cells / Q000187:drug effects / Q000473:pathology*; D008875:Middle Aged; D016328:NF-kappa B / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D055815:Young Adult; D019892:eIF-2 Kinase / Q000378:metabolism
chemical_list: D051702:Activating Transcription Factor 6; D000974:Antibodies, Antinuclear; D000091342:Endoplasmic Reticulum Chaperone BiP; D004722:Endoribonucleases; D016328:NF-kappa B; D017346:Protein Serine-Threonine Kinases; D019892:eIF-2 Kinase; C497111:ATF6 protein, human; C000717247:HSPA5 protein, human; C528229:ERN1 protein, human