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Lucia Pavlikova, Mario Seres, Denisa Imrichova, Milan Hano, Andrej Rusnak, Martina Zamorova, Jaroslav Katrlik, Albert Breier, Zdena Sulova
In P-gp-positive cell variants obtained from L1210 cells either by selection with vincristine (L1210/R) or by transfection with the human gene encoding P-gp (L1210/T), we have previously described cross-resistance to tunicamycin (TNM), a protein N-glycosylation inhibitor. Here we studied whether this cross-resistance also underlies P-gp-positive variants of human acute myeloid leukemia cells (AML) derived from SKM-1 and MOLM-13 cells (SKM-1/VCR, SKM-1/LEN, MOLM-13/VCR) by selection with vincristine (VCR) and lenalidomide (LEN)...
October 2016: General Physiology and Biophysics
Emily C Lumley, Acadia R Osborn, Jessica E Scott, Amanda G Scholl, Vicki Mercado, Young T McMahan, Zachary G Coffman, Jay L Brewster
The endoplasmic reticulum (ER) has the ability to signal organelle dysfunction via a complex signaling network known as the unfolded protein response (UPR). In this work, hamster fibroblast cells exhibiting moderate levels of ER stress were compared to those exhibiting severe ER stress. Inhibition of N-linked glycosylation was accomplished via a temperature-sensitive mutation in the Dad1 subunit of the oligosaccharyltransferase (OST) complex or by direct inhibition with tunicamycin (Tm). Temperature shift (TS) treatment generated weak activation of ER stress signaling when compared to doses of Tm that are typically used in ER stress studies (500-1000 nM)...
October 20, 2016: Cell Stress & Chaperones
Xia Wu, Elena E Paskaleva, Krunal K Mehta, Jonathan S Dordick, Ravi S Kane
Bacterial lysins are potent antibacterial enzymes with potential applications in the treatment of bacterial infections. Some lysins lose activity in the growth media of target bacteria, and the underlying mechanism remains unclear. Here we use CD11, an autolysin of Clostridium difficile, as a model lysin to demonstrate that the inability of this enzyme to kill C. difficile in growth medium is not associated with inhibition of the enzyme activity by medium, or the modification of the cell wall peptidoglycan...
October 19, 2016: Scientific Reports
Abdikarim Abdullahi, Mile Stanojcic, Alexandra Parousis, David Patsouris, Marc G Jeschke
The Endoplasmic Reticulum (ER) is a critical organelle that synthesizes secretory proteins and serves as the main calcium storage site of the cell. The accumulation of unfolded proteins at the ER results in ER stress. Although the association between ER stress and the pathogenesis of many metabolic conditions have been well characterized using both in vivo and in vitro models, no standardized model concerning ER stress exists. Here we report a standardized model of ER stress using two well characterized ER stress inducing agents, thapsigargin and tunicamycin...
October 17, 2016: Shock
Modar Kassan, Ajit Vikram, Qiuxia Li, Young-Rae Kim, Santosh Kumar, Julia Jacob, Irani Kaikobad
OBJECTIVE: Endoplasmic reticulum (ER) stress leads to vascular endothelial dysfunction in hypertension. The role of microRNAs in vascular ER stress is not fully understood. Here we examined the role of vascular microRNA-204 (miR-204) in inducing endothelial ER stress and dysfunction by governing the expression of the SIRTUIN1 (SIRT1) lysine deacetylase. DESIGN AND METHOD: Human Umbilical Vein cells (HUVECs) were treated with tunicamycin or transfected with miR-204 Mimic or siRNA SIRT1...
September 2016: Journal of Hypertension
Wenting Ai, Min Wu, Lin Chen, Baozhou Jiang, Mian Mu, Lihua Liu, Zuyi Yuan
The effects of ghrelin, a peptide hormone, on atherogenesis are mainly beneficial. This study aimed to investigate whether ghrelin ameliorates atherosclerosis (AS) by preventing endoplasmic reticulum stress (ERS). AS was induced by a high-fat diet in ApoE(-/-) mice. AS lesions in aortas were detected by Oil-red O staining, and the inner diameter and intima-media thickness (IMT) of the abdominal aorta were analyzed by ultrasonography. The protein expression of the ERS markers 78-kDa glucose-regulated protein, C/EBP homologous protein, and active caspase-12 was detected by western blot analysis...
October 18, 2016: Fundamental & Clinical Pharmacology
Tapasi Rana, Pravallika Kotla, Roderick Fullard, Marina Gorbatyuk
Expression of T17M rhodopsin (T17M) in rods activates the Unfolded Protein Response (UPR) and leads to the development of autosomal dominant retinitis pigmentosa (adRP). The rod death occurs in adRP retinas prior to cone photoreceptor death, so the mechanism by which cone photoreceptors die remains unclear. Therefore, the goal of the study was to verify whether UPR in rods induces TNFa-mediated signaling to the cones and to determine whether the TNFa deficit could prevent adRP cone cell death. Primary rod photoreceptors and cone-derived 661W cells transfected with siRNA against TNFa were treated with tunicamycin to mimic activation of UPR in T17M retinas expressing normal and reduced TNFa levels...
October 14, 2016: Biochimica et Biophysica Acta
Roi Isaac, Ido Goldstein, Noa Furth, Neta Zilber, Sarina Streim, Sigalit Boura-Halfon, Eytan Elhanany, Varda Rotter, Moshe Oren, Yehiel Zick
Earlier reported small interfering RNA (siRNA) high-throughput screens, identified seven-transmembrane superfamily member 3 (TM7SF3) as a novel inhibitor of pancreatic β-cell death. Here we show that TM7SF3 maintains protein homeostasis and promotes cell survival through attenuation of ER stress. Overexpression of TM7SF3 inhibits caspase 3/7 activation. In contrast, siRNA-mediated silencing of TM7SF3 accelerates ER stress and activation of the unfolded protein response (UPR). This involves inhibitory phosphorylation of eukaryotic translation initiation factor 2α activity and increased expression of activating transcription factor-3 (ATF3), ATF4 and C/EBP homologous protein, followed by induction of apoptosis...
October 14, 2016: Cell Death and Differentiation
Jason Gavin, Fran Quilty, Ferenc Majer, Georgina Gilsenan, Anne Marie Byrne, Aideen Long, Gabor Radics, John F Gilmer
Tauroursodeoxycholic acid (TUDCA) is a cytoprotective ER stress inhibitor and chemical chaperone. It has therapeutic potential in a wide array of diseases but a specific macromolecular target or molecular mechanism of action remains obscure. This Letter describes an effective new synthetic approach to taurine conjugation of bile acids which we used to prepare 3α-dansyl TUDCA (4) as a probe for TUDCA actions. As a model of ER stress we used the hepatocarcinoma cell line HUH7 and stimulation with either deoxycholic acid (DCA, 200μM) or tunicamycin (5μg/ml) and measured levels of Bip/GRP78, ATF4, CHOP and XBP1s/XBP1u...
June 23, 2016: Bioorganic & Medicinal Chemistry Letters
Lu Gan, Zhenjiang Liu, Tianjiao Wu, Fei Feng, Chao Sun
Alpha-melanocyte stimulating hormone (αMSH) has an important role in the regulation of body weight and energy expenditure. Nevertheless, the molecular mechanisms of circulating αMSH on preadipocyte proliferation remain elusive. We found αMSH was reduced by high fat diet (HFD) while leptin was elevated in adipose tissue. Leptin resistance and endoplasmic reticulum (ER) stress of adipose tissue were increased in obese mice. αMSH increased leptin sensitivity and alleviated ER stress along with increased p-STAT3 level and reduced SOCS3, GRP78, CHOP, ATF4, p27 and p53 levels...
October 5, 2016: Biochimica et Biophysica Acta
Jacey H Ma, Joshua J Wang, Junhua Li, Bruce A Pfeffer, Yiming Zhong, Sarah X Zhang
Purpose: The retinal pigment epithelium (RPE) tight junctions play a pivotal role in maintaining the homeostatic environment of the neural retina. Herein, we investigated the role of X-box binding protein 1 (XBP1), an endoplasmic reticulum (ER) stress-responsive transcription factor, in regulation of RPE tight junctions. Methods: Human RPE cell line (ARPE-19) and primary primate RPE cells were used for in vitro experiments and RPE-specific XBP1 knockout (KO) mice were used for in vivo study...
October 1, 2016: Investigative Ophthalmology & Visual Science
T Shen, O Alvarez-Garcia, Y Li, M Olmer, M K Lotz
OBJECTIVES: Aging is an important osteoarthritis (OA) risk factor and compromised stress defense responses may mediate this risk. The Sestrins (Sesn) promote cell survival under stress conditions and regulate AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) signaling. This study examined Sesn expression in normal and OA cartilage and functions of Sesn in chondrocytes. METHODS: Sesn expression in human and mouse normal and OA cartilage was analyzed by quantitative polymerase chain reaction (PCR) and immunohistochemistry...
September 29, 2016: Osteoarthritis and Cartilage
Hisaka Kurita, Rika Okuda, Kazuki Yokoo, Masatoshi Inden, Isao Hozumi
Endoplasmic reticulum (ER) stress has been thought to be involved to neurodegenerative diseases such as Alzheimer's disease (AD) or Amyotrophic lateral sclerosis (ALS). The previous studies have shown that SLC30A3 level is decreased in prefrontal cortex of AD patients. In addition, we have shown that level of zinc (Zn) is increased in cerebrospinal fluid and SLC30A3 level is decreased in spinal cord of ALS patients. It was thought that both SLC30A3 and ER stress could be related to the cause of AD and ALS, however the relationship between ER stress and SLC30A3 has not been elucidated...
October 28, 2016: Biochemical and Biophysical Research Communications
Y T Liu, S R Li, Z Wang, J Z Xiao
Objective: To profile the gene expression changes associated with endoplasmic reticulum stress in INS-1-3 cells induced by thapsigargin (TG) and tunicamycin (TM). Methods: Normal cultured INS-1-3 cells were used as a control. TG and TM were used to induce endoplasmic reticulum stress in INS-1-3 cells. Digital gene expression profiling technique was used to detect differentially expressed gene. The changes of gene expression were detected by expression pattern clustering analysis, gene ontology (GO) function and pathway enrichment analysis...
September 13, 2016: Zhonghua Yi Xue za Zhi [Chinese medical journal]
H Gao, X Y Zhang, L Y Yue, Z Y Liu, N N Jia, D X Chen, Z P Duan, F Ren
Objective: To study the role of endoplasmic reticulum (ER) stress-mediated glycogen synthase kinase 3β (GSK3β) activity in the pathological process of liver injury in acute liver failure (ALF) mice. Methods: ALF model was established by intraperitoneal injection of D-galactosamine/lipopolysaccharide (D-GalN/LPS) in C57BL/6 mice. The mice were divided into control group (n=10), ALF model group (n=18), 4-phenylbutyrate (4-PBA, an ER stress inhibitor) group (n=18) and SB216763 (a specific inhibitor of GSK3β) group (n=16)...
September 13, 2016: Zhonghua Yi Xue za Zhi [Chinese medical journal]
Francesca De Marchis, Andrea Pompa, Michele Bellucci
The classical Golgi pathway is not the only mechanism for vacuolar protein transport in plants because alternative transport mechanisms have been described. The existence of these alternative pathways can be demonstrated using several chemicals and here we describe the use of brefeldin A (BFA), endo-β-N-acetylglucosaminidase H (Endo-H), and tunicamycin, on isolated tobacco leaf protoplasts. Two main methods are illustrated in this chapter, protoplast pulse-chase followed by protein immunoprecipitation, and protoplast immunofluorescence...
2016: Methods in Molecular Biology
Valentín Cóppola-Segovia, Clarissa Cavarsan, Flavia G Maia, Anete C Ferraz, Lia S Nakao, Marcelo Ms Lima, Silvio M Zanata
Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive death of dopaminergic neurons of the substantia nigra pars compacta (SNpc), leading to the major clinical abnormalities that characterize this disease. Although PD's etiology is unknown, α-synuclein aggregation plays a pivotal role in PD pathogenesis, which could be associated to some pathological processes such as oxidative stress, endoplasmic reticulum (ER) stress, impaired protein degradation, and mitochondrial dysfunction...
September 22, 2016: Molecular Neurobiology
Modar Kassan, Ajit Vikram, Qiuxia Li, Young-Rae Kim, Santosh Kumar, Julia Jacob, Irani Kaikobad
OBJECTIVE: Endoplasmic reticulum (ER) stress leads to vascular endothelial dysfunction in hypertension. The role of microRNAs in vascular ER stress is not fully understood. Here we examined the role of vascular microRNA-204 (miR-204) in inducing endothelial ER stress and dysfunction by governing the expression of the SIRTUIN1 (SIRT1) lysine deacetylase. DESIGN AND METHOD: Human Umbilical Vein cells (HUVECs) were treated with tunicamycin or transfected with miR-204 Mimic or siRNA SIRT1...
September 2016: Journal of Hypertension
Kapil Sareen-Khanna, Joan Papillon, Simon S Wing, Andrey V Cybulsky
Kidney cell injury may be associated with protein misfolding and induction of endoplasmic reticulum (ER) stress. Examples include complement-induced glomerular epithelial cell (GEC)/podocyte injury in membranous nephropathy, and ischemia-reperfusion injury. Renal cell injury can also result from mutations in integral proteins, which lead to their misfolding and accumulation. Certain nephrin missense mutants misfold, accumulate in the ER, and induce ER stress. We examined if enhancement of ubiquitin-proteasome system (UPS) function may facilitate proteostasis and confer protection against injury...
September 14, 2016: American Journal of Physiology. Renal Physiology
Zheng Mou, Yu-He Yuan, Yu-Xia Lou, Yang Heng, Ju-Yang Huang, Cong-Yuan Xia, Yan Gao, Cheng-Gen Zhu, Shi-Feng Chu, Piao Luo, Jian-Gong Shi, Nai-Hong Chen
AIM: Accumulation of α-synuclein (α-syn) in the brain is a characteristic of Parkinson's disease (PD). In this study, we investigated whether treatment with tunicamycin, an endoplasmic reticulum (ER) stress inducer, led to the accumulation of α-syn in PC12 cells, and where α-syn protein was accumulated, and, finally, whether bibenzyl compound 20c, a novel compound isolated from Gastrodia elata (Tian ma), could alleviate the accumulation of α-syn and ER stress activation in tunicamycin-treated PC12 cells...
September 12, 2016: Acta Pharmacologica Sinica
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