Dataset Information

HLA-B35 and dsRNA induce endothelin-1 via activation of ATF4 in human microvascular endothelial cells.

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/eIF2?/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 eIF2?/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-?B pathways are also required for ET-1 upregulation by these agonists. Formation of the ATF4/c-JUN complex, but not the ATF4/NF-?B 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 eIF2?/ATF4 during activation of endothelial cells.

SUBMITTER: Lenna S

PROVIDER: S-EPMC3575387 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

HLA-B35 and dsRNA induce endothelin-1 via activation of ATF4 in human microvascular endothelial cells.

Lenna Stefania S Chrobak Izabela I Farina G Alessandra GA Rodriguez-Pascual Fernando F Lamas Santiago S Lafyatis Robert R Scorza Raffaella R Trojanowska Maria M

PloS one 20130218 2

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 exp ...[more]

PMID: 23441162

Similar Datasets

Project description:Plasma homocysteine (Hcy) levels are positively correlated with cardiovascular mortality in diabetes. However, the joint effect of hyperhomocysteinemia (HHcy) and hyperglycemia (HG) on endothelial dysfunction (ED) and the underlying mechanisms have not been studied. Mild (22 µmol/L) and moderate (88 µmol/L) HHcy were induced in cystathionine β-synthase wild-type (Cbs(+/+)) and heterozygous-deficient (Cbs(-/+)) mice by a high-methionine (HM) diet. HG was induced by consecutive injection of streptozotocin. We found that HG worsened HHcy and elevated Hcy levels to 53 and 173 µmol/L in Cbs(+/+) and Cbs(-/+) mice fed an HM diet, respectively. Both mild and moderate HHcy aggravated HG-impaired endothelium-dependent vascular relaxation to acetylcholine, which was completely abolished by endothelial nitric oxide synthase (eNOS) inhibitor N(G)-nitro-L-arginine methyl ester. HHcy potentiated HG-induced calpain activation in aortic endothelial cells isolated from Cbs mice. Calpain inhibitors rescued HHcy- and HHcy/HG-induced ED in vivo and ex vivo. Moderate HHcy- and HG-induced μ-calpain activation was potentiated by a combination of HHcy and HG in the mouse aorta. μ-Calpain small interfering RNA (μ-calpsiRNA) prevented HHcy/HG-induced ED in the mouse aorta and calpain activation in human aortic endothelial cells (HAECs) treated with DL-Hcy (500 µmol/L) and d-glucose (25 mmol) for 48 h. In addition, HHcy accelerated HG-induced superoxide production as determined by dihydroethidium and 3-nitrotyrosin staining and urinary 8-isoprostane/creatinine assay. Antioxidants rescued HHcy/HG-induced ED in mouse aortas and calpain activation in cultured HAECs. Finally, HHcy potentiated HG-suppressed nitric oxide production and eNOS activity in HAECs, which were prevented by calpain inhibitors or μ-calpsiRNA. HHcy aggravated HG-increased phosphorylation of eNOS at threonine 497/495 (eNOS-pThr497/495) in the mouse aorta and HAECs. HHcy/HG-induced eNOS-pThr497/495 was reversed by µ-calpsiRNA and adenoviral transduced dominant negative protein kinase C (PKC)β2 in HAECs. HHcy and HG induced ED, which was potentiated by the combination of HHcy and HG via μ-calpain/PKCβ2 activation-induced eNOS-pThr497/495 and eNOS inactivation.

Dataset Information

HLA-B35 and dsRNA induce endothelin-1 via activation of ATF4 in human microvascular endothelial cells.

Publications

HLA-B35 and dsRNA induce endothelin-1 via activation of ATF4 in human microvascular endothelial cells.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets