HLA-B35 and dsRNA induce endothelin-1 via activation of ATF4 in human microvascular endothelial cells
Authors: Santiago Lamas
G Alessandra Farina
Fernando Rodriguez-Pascual
Izabela Chrobak
Stefania Lenna
Robert Lafyatis
Maria Trojanowska
Raffaella Scorza
Journal: PLoS ONE (2013)
Discipline: Multidisciplinary
Keywords: Endothelin 1; HLA-B35; Poly(I:C); HDMECs; ER stress
Affiliations: Arthritis Center, Boston University School of Medicine, Boston, Massachusetts, United States of America.

Abstract:  Endothelin 1 (ET-1) is a key regulator of vascular homeostasis. We have recently reported that the presence of Human antigen class I, HLA-B35, contributes to human dermal microvascular endothelial cell (HDMEC) dysfunction by upregulating ET-1 and proinflammatory genes. Likewise, a Toll-like receptor 3 (TLR3) ligand, Poly(I:C), was shown to induce ET-1 expression in HDMECs. The goal of this study was to determine the molecular mechanism of ET-1 induction by these two agonists. Because HLA-B35 expression correlated with induction of Binding Immunoglobulin Protein (BiP/GRP78) and several heat shock proteins, we first focused on ER stress and unfolded protein response (UPR) as possible mediators of this response. ER stress inducer, Thapsigargin (TG), HLA-B35, and Poly(I:C) induced ET-1 expression with similar potency in HDMECs. TG and HLA-B35 activated the PERK/eIF2α/ATF4 branch of the UPR and modestly increased the spliced variant of XBP1, but did not affect the ATF6 pathway. Poly(I:C) also activated eIF2α/ATF4 in a protein kinase R (PKR)-dependent manner. Depletion of ATF4 decreased basal expression levels of ET-1 mRNA and protein, and completely prevented upregulation of ET-1 by all three agonists. Additional experiments have demonstrated that the JNK and NF-κB pathways are also required for ET-1 upregulation by these agonists. Formation of the ATF4/c-JUN complex, but not the ATF4/NF-κB complex was increased in the agonist treated cells. The functional role of c-JUN in responses to HLA-B35 and Poly(I:C) was further confirmed in ET-1 promoter assays. This study identified ATF4 as a novel activator of the ET-1 gene. The ER stress/UPR and TLR3 pathways converge on eIF2α/ATF4 during activation of endothelial cells. 

Retracted: Yes

PubPeer comments:
 Figures 3 and 4: some panels or parts of panels appear to look similar to each other. ![file] Reported to the journal in 2015. , 
 Retraction, 22 Oct 2020, found here: https: journals.plos.org plosone article?id=10.1371 journal.pone.0241404 From the retraction notice: *After this article [1] was published, concerns were raised about results reported in Figs 3 and 4. Boston University investigated this work and determined that images in Figs 3 and 4 had been inappropriately duplicated, manipulated, and mislabeled.* ...  *The authors requested retraction of the article and stated that the underlying data for these results are not available. In light of the above concerns, and in line with the institutionu2019s recommendation, the PLOS ONE Editors retract this article.* *SLe, GAF, FRP, SLa, RL, and MT agreed with the retraction, though SLe noted that she stands by the articleu2019s findings. SLe, GAF, SLa, and MT apologize for the issues with the published article. IC and RS either could not be reached or did not respond directly.*  This work was supported by the National Institutes of Health, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) P50 AR060780 to MT and RL, Scleroderma Foundation grants to MT and AF, and by a grant from Gruppo Italiano per la Lotta alla Sclerodermia (GILS) to SL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. ,