scholarly journals The Regulatory Role of GBF1 on Osteoclast Activation Through EIF2a Mediated ER Stress and Novel Marker FAM129A Induction

2021 ◽  
Vol 9 ◽  
Author(s):  
Cailing Wen ◽  
Yuheng Zhou ◽  
Yanting Xu ◽  
Huijing Tan ◽  
Caixia Pang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Early Stage ◽  
Specific Inhibitor ◽  
Brefeldin A ◽  
Vesicular Trafficking ◽  
Functional Roles ◽  
Membrane Reorganization ◽  
Cytoskeleton Remodeling ◽  
Arf Gtpases

Bone-resorbing activities of osteoclasts (OCs) are highly dependent on actin cytoskeleton remodeling, plasma membrane reorganization, and vesicle trafficking pathways, which are partially regulated by ARF-GTPases. In the present study, the functional roles of Golgi brefeldin A resistance factor 1 (GBF1) are proposed. GBF1 is responsible for the activation of the ARFs family and vesicular transport at the endoplasmic reticulum–Golgi interface in different stages of OCs differentiation. In the early stage, GBF1 deficiency impaired OCs differentiation and was accompanied with OCs swelling and reduced formation of mature OCs, indicating that GBF1 participates in osteoclastogenesis. Using siRNA and the specific inhibitor GCA for GBF1 knockdown upregulated endoplasmic reticulum stress-associated signaling molecules, including BiP, p-PERK, p-EIF2α, and FAM129A, and promoted autophagic Beclin1, Atg7, p62, and LC3 axis, leading to apoptosis of OCs. The present data suggest that, by blocking COPI-mediated vesicular trafficking, GBF1 inhibition caused intense stress to the endoplasmic reticulum and excessive autophagy, eventually resulting in the apoptosis of mature OCs and impaired bone resorption function.

scholarly journals The Role of Endoplasmic Reticulum in the Differential Endurance against Redox Stress in Cortical and Spinal Astrocytes from the Newborn SOD1G93A Mouse Model of Amyotrophic Lateral Sclerosis

Antioxidants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1392
Author(s):  
Cecilia Marini ◽  
Vanessa Cossu ◽  
Mandeep Kumar ◽  
Marco Milanese ◽  
Katia Cortese ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Metabolic Response ◽  
Early Stage ◽  
Pentose Phosphate ◽  
Redox Stress ◽  
Als Patients ◽  
Selective Enhancement ◽  
Respiratory Uncoupling ◽  
Lateral Sclerosis

Recent studies reported that the uptake of [18F]-fluorodeoxyglucose (FDG) is increased in the spinal cord (SC) and decreased in the motor cortex (MC) of patients with ALS, suggesting that the disease might differently affect the two nervous districts with different time sequence or with different mechanisms. Here we show that MC and SC astrocytes harvested from newborn B6SJL-Tg (SOD1G93A) 1Gur mice could play different roles in the pathogenesis of the disease. Spectrophotometric and cytofluorimetric analyses showed an increase in redox stress, a decrease in antioxidant capacity and a relative mitochondria respiratory uncoupling in MC SOD1G93A astrocytes. By contrast, SC mutated cells showed a higher endurance against oxidative damage, through the increase in antioxidant defense, and a preserved respiratory function. FDG uptake reproduced the metabolic response observed in ALS patients: SOD1G93A mutation caused a selective enhancement in tracer retention only in mutated SC astrocytes, matching the activity of the reticular pentose phosphate pathway and, thus, of hexose-6P dehydrogenase. Finally, both MC and SC mutated astrocytes were characterized by an impressive ultrastructural enlargement of the endoplasmic reticulum (ER) and impairment in ER–mitochondria networking, more evident in mutated MC than in SC cells. Thus, SOD1G93A mutation differently impaired MC and SC astrocyte biology in a very early stage of life.

Initiation and maintenance of NGF-stimulated neurite outgrowth requires activation of a phosphoinositide 3-kinase

1996 ◽  
Vol 109 (2) ◽  
pp. 289-300 ◽  
Author(s):  
T.R. Jackson ◽  
I.J. Blader ◽  
L.P. Hammonds-Odie ◽  
C.R. Burga ◽  
F. Cooke ◽  
...  
Keyword(s):  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Specific Inhibitor ◽  
Morphological Differentiation ◽  
Sympathetic Neuron ◽  
Neuronal Morphology ◽  
Regulatory Subunit ◽  
Membrane Reorganization ◽  
Phosphoinositide 3 Kinase

Application of nerve growth factor (NGF) to PC12 cells stimulates a programme of physiological changes leading to the development of a sympathetic neuron like phenotype, one aspect of which is the development of a neuronal morphology characterised by the outgrowth of neuritic processes. We have investigated the role of phosphoinositide 3-kinase in NGF-stimulated morphological differentiation through two approaches: firstly, preincubation with wortmannin, a reputedly specific inhibitor of phosphoinositide kinases, completely inhibited initial morphological responses to NGF, the formation of actin filament rich microspikes and subsequent neurite outgrowth. This correlated with wortmannin inhibition of NGF-stimulated phosphatidylinositol(3,4,5)trisphosphate (PtdInsP3) and phosphatidylinositol(3,4)bisphosphate (PtdIns(3,4)P2) production and with inhibition of NGF-stimulated phosphoinositide 3-kinase activity in anti-phosphotyrosine immunoprecipitates. Secondly, the overexpression of a mutant p85 regulatory subunit of the phosphoinositide 3-kinase, which cannot interact with the catalytic p110 subunit, also substantially inhibited the initiation of NGF-stimulated neurite outgrowth. In addition, we found that wortmannin caused a rapid collapse of more mature neurites formed following several days exposure of PC12 cells to NGF. These results indicate that NGF-stimulated neurite outgrowth requires the activity of a tyrosine kinase regulated PI3-kinase and suggest that the primary product of this enzyme, PtdInsP3, is a necessary second messenger for the cytoskeletal and membrane reorganization events which occur during neuronal differentiation.

scholarly journals Fluorescent conjugates of brefeldin A selectively stain the endoplasmic reticulum and Golgi complex of living cells.

1995 ◽  
Vol 43 (9) ◽  
pp. 907-915 ◽  
Author(s):  
Y Deng ◽  
J R Bennink ◽  
H C Kang ◽  
R P Haugland ◽  
J W Yewdell
Keyword(s):  
Endoplasmic Reticulum ◽  
Lipid Bilayers ◽  
Golgi Complex ◽  
Intracellular Transport ◽  
Brefeldin A ◽  
Living Cells ◽  
Vesicular Trafficking ◽  
Cellular Functions ◽  
Animal Cells ◽  
Specific Localization

The fungal metabolite brefeldin A (BFA) interferes with vesicular trafficking in most animal cells. To gain insight into the mechanism of BFA action, we esterified it to the fluorophore, boron dipyromethene difluoride (BODIPY). BODIPY-BEA localized predominantly in the endoplasmic reticulum (ER) and Golgi complex of viable cells and was extracted by detergent treatment, suggesting it interacts primarily with lipid bilayers. The localization of the conjugate is conferred by BFA, since free BODIPY or BODIPY esterified to cyclopentanol did not specifically localize to internal membranes. BODIPY-BFA exhibited a similar biological activity to BFA, but only when used at higher concentrations and after a delay. HPLC analysis revealed that over this period, cells converted BODIPY-BFA to species co-eluting with free BODIPY and BFA. Therefore, BODIPY-BFA is probably inactive until BFA is released by cellular esterases. The specific localization of BODIPY-BFA to the ER and Golgi complex suggests that BFA might exert its effects on vesicular trafficking by perturbing the lipid bilayer of its target organelles. Because BODIPY-BFA intensely stains the ER at concentrations that have no discernible effects on intracellular transport or other cellular functions, it should be useful for visualizing the ER in living cells.

scholarly journals Dynein Supports Motility of Endoplasmic Reticulum in the FungusUstilago maydis

2002 ◽  
Vol 13 (3) ◽  
pp. 965-977 ◽  
Author(s):  
Roland Wedlich-Söldner ◽  
Irene Schulz ◽  
Anne Straube ◽  
Gero Steinberg
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Intracellular Transport ◽  
Fluorescent Protein ◽  
Brefeldin A ◽  
Cytoplasmic Dynein ◽  
Organelle Transport ◽  
Minor Importance ◽  
Dependent Transport

The endoplasmic reticulum (ER) of most vertebrate cells is spread out by kinesin-dependent transport along microtubules, whereas studies in Saccharomyces cerevisiae indicated that motility of fungal ER is an actin-based process. However, microtubules are of minor importance for organelle transport in yeast, but they are crucial for intracellular transport within numerous other fungi. Herein, we set out to elucidate the role of the tubulin cytoskeleton in ER organization and dynamics in the fungal pathogen Ustilago maydis. An ER-resident green fluorescent protein (GFP)-fusion protein localized to a peripheral network and the nuclear envelope. Tubules and patches within the network exhibited rapid dynein-driven motion along microtubules, whereas conventional kinesin did not participate in ER motility. Cortical ER organization was independent of microtubules or F-actin, but reformation of the network after experimental disruption was mediated by microtubules and dynein. In addition, a polar gradient of motile ER-GFP stained dots was detected that accumulated around the apical Golgi apparatus. Both the gradient and the Golgi apparatus were sensitive to brefeldin A or benomyl treatment, suggesting that the gradient represents microtubule-dependent vesicle trafficking between ER and Golgi. Our results demonstrate a role of cytoplasmic dynein and microtubules in motility, but not peripheral localization of the ER inU. maydis.

scholarly journals Legionella hijacks the host Golgi-to-ER retrograde pathway for the association of Legionella-Containing vacuole with the ER

2021 ◽  
Vol 17 (3) ◽  
pp. e1009437
Author(s):  
Mio Kawabata ◽  
Honoka Matsuo ◽  
Takumi Koito ◽  
Misaki Murata ◽  
Tomoko Kubori ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Legionella Pneumophila ◽  
Early Stage ◽  
Physiological Role ◽  
Snare Proteins ◽  
Negative Bacterium ◽  
Gram Negative ◽  
Bacterial Proteins ◽  
Host Membrane

Legionella pneumophila (L. pneumophila) is a gram-negative bacterium that replicates in a compartment that resembles the host endoplasmic reticulum (ER). To create its replicative niche, L. pneumophila manipulates host membrane traffic and fusion machineries. Bacterial proteins called Legionella effectors are translocated into the host cytosol and play a crucial role in these processes. In an early stage of infection, Legionella subverts ER-derived vesicles (ERDVs) by manipulating GTPase Rab1 to facilitate remodeling of the Legionella-containing vacuole (LCV). Subsequently, the LCV associates with the ER in a mechanism that remains elusive. In this study, we show that L. pneumophila recruits GTPases Rab33B and Rab6, which regulate vesicle trafficking from the Golgi to the ER, to the LCV to promote the association of LCV with the ER. We found that recruitment of Rab6 to the LCV depends on Rab33B. Legionella effector SidE family proteins, which phosphoribosyl-ubiquitinate Rab33B, were found to be necessary for the recruitment of Rab33B to the LCV. Immunoprecipitation experiments revealed that L. pneumophila facilitates the interaction of Rab6 with ER-resident SNAREs comprising syntaxin 18, p31, and BNIP1, but not tethering factors including NAG, RINT-1, and ZW10, which are normally required for syntaxin 18-mediated fusion of Golgi-derived vesicles with the ER. Our results identified a Rab33B-Rab6 cascade on the LCV and the interaction of Rab6 with ER-resident SNARE proteins for the association of LCV with the ER and disclosed the unidentified physiological role of SidE family proteins.

scholarly journals Tetraspanin CD9 regulates invasion during mouse embryo implantation

2006 ◽  
Vol 36 (1) ◽  
pp. 121-130 ◽  
Author(s):  
W M Liu ◽  
Y J Cao ◽  
Y J Yang ◽  
J Li ◽  
Z Hu ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Embryo Implantation ◽  
Specific Inhibitor ◽  
Matrix Metalloproteinase 2 ◽  
Dependent Manner ◽  
Functional Roles ◽  
Phosphoinositide 3 Kinase ◽  
Dose Dependent

The expression of tetraspanin CD9 was found on blastocysts in mice and endometrium epithelial cells in human and bovine. However, it remains unknown how CD9 is involved in the precise dialogue between embryo and uterus during early pregnancy. This study was designed to investigate the functional roles of CD9 in the embryo implantation with monoclonal antibody against CD9 protein (anti-CD9 mAb) and antisense oligonucleotide against CD9 gene (AS-CD9). Our results showed that intrauterine injection of anti-CD9 mAb on day 4 of pregnancy significantly increased the number of embryos implanted (7.24±0.39 versus 4.04±0.38). In vitro, anti-CD9 mAb or AS-CD9 significantly enhanced embryo-outgrowth ability on the monolayer of uterus epithelial cells in a dose-dependent manner. However, the attachment of blastocysts to epithelial cells was unaffected. Furthermore, we found that anti-CD9 mAb or AS-CD9 stimulated matrix metalloproteinase 2 (MMP-2) production of blastocysts on Fibronectin. LY294002, a specific inhibitor of phosphoinositide 3-kinase, was able to counteract the effect of anti-CD9 mAb and AS-CD9 on outgrowth ability and production of MMP-2. Our results indicated that CD9 played a role of inhibiting embryo implantation. CD9 was able to impair embryo invasion and the production of MMP-2 through the phosphoinositide 3-kinase signaling pathway.

Modulation of intracellular Ca2+ by glucose in MDCK cells: role of endoplasmic reticulum Ca(2+)-ATPase

1995 ◽  
Vol 268 (4) ◽  
pp. F671-F679 ◽  
Author(s):  
Y. H. Lien ◽  
X. Wang ◽  
R. J. Gillies ◽  
R. Martinez-Zaguilan
Keyword(s):  
Endoplasmic Reticulum ◽  
Mdck Cells ◽  
Cyclopiazonic Acid ◽  
Tubuloglomerular Feedback ◽  
Free Calcium ◽  
Functional Roles ◽  
Atpase Inhibitors ◽  
Dose Dependent Fashion ◽  
Cl Channels

Intracellular free calcium ([Ca2+]i) has multiple functional roles in renal epithelia, including mediating ligand- and volume-activated K+ and Cl- channels, modulating the permeability of apical membrane to Na+, and regulating tubuloglomerular feedback. We investigated glucose effects on intracellular pH (pHi) and [Ca2+]i in Madin-Darby canine kidney (MDCK) cells using fluorescent probes, SNARF-1 and fura 2, respectively. The addition of glucose decreased both pHi and [Ca2+]i in a dose-dependent fashion. Thapsigargin (TG) and cyclopiazonic acid (CPA), well-known endoplasmic reticulum (ER) Ca(2+)-adenosinetriphosphatase (Ca(2+)-ATPase) inhibitors, abolished the glucose-induced [Ca2+]i decrease. Without glucose, 1 microM TG induced a sustained elevation in [Ca2+]i, which increased further with glucose addition, whereas 15 microM CPA induced a transient increase in [Ca2+]i that was not affected by further addition of glucose. The sustained elevation in [Ca2+]i induced by TG was dependent on extracellular Ca2+. TG-induced [Ca2+]i increase was modulated by glucose, i.e., at higher glucose concentrations, TG induced a larger and more rapid rise in [Ca2+]i. We conclude that glucose has dual effects on [Ca2+]i regulation. Glucose alone reduces [Ca2+]i by activating ER-type Ca(2+)-ATPase, since this phenomenon is TG and CPA sensitive. In the presence of TG, glucose increases [Ca2+]i probably by increasing Ca2+ entry. Our data suggest a model in which TG activates capacitative Ca2+ entry by depletion of the ER Ca2+ pool. Glucose increases TG-induced [Ca2+]i elevation by further enhancing capacitative Ca2+ entry.

The role of endoplasmic reticulum stress in the early stage of diabetic retinopathy

2009 ◽  
Vol 48 (2) ◽  
pp. 103-111 ◽  
Author(s):  
Bin Li ◽  
Hong Sheng Wang ◽  
Gui Gang Li ◽  
Min Jian Zhao ◽  
Min Hong Zhao
Keyword(s):  
Endoplasmic Reticulum ◽  
Diabetic Retinopathy ◽  
Endoplasmic Reticulum Stress ◽  
Early Stage

scholarly journals Inhibition of protein kinases C prevents murine cytomegalovirus replication

2005 ◽  
Vol 86 (8) ◽  
pp. 2153-2161 ◽  
Author(s):  
Natalia Kučić ◽  
Hana Mahmutefendić ◽  
Pero Lučin
Keyword(s):  
Protein Phosphorylation ◽  
Protein Kinases ◽  
Phorbol Esters ◽  
Early Stage ◽  
Specific Inhibitor ◽  
Cellular Protein ◽  
Protein Kinase Inhibitors ◽  
Murine Cytomegalovirus ◽  
Mcmv Infection

For successful establishment of infection and initiation of the replication cycle, murine cytomegalovirus (MCMV) utilizes cellular structures and functions, including cell-membrane penetration, capsid dismantling and cytosolic transport of viral DNA into the nucleus. These early events of MCMV infections are dependent on cellular regulatory mechanisms, primarily protein phosphorylation. In the present study, protein kinase inhibitors were used to explore the role of protein phosphorylation mediated by protein kinases C (PKCs) in the very early events of MCMV infection. Inhibitory effects were determined by immunofluorescence and Western blot analysis of MCMV IE1 and E1 protein expression and by production of infectious virions in cell culture. It was found that H-7, a broadly specific inhibitor of cellular protein kinases, prevented virus replication in a dose-dependent and reversible manner, and that the block in replication occurred very early in infection. More specific PKC inhibitors (sangivamycin, calphostin C and bisindolylmaleimide II), Ca2+/calmodulin inhibitors (EDTA and W7) and phorbol esters (PMA) were used to dissect PKC-subclass contribution in the very early events of MCMV replication. The results indicate that the role of diacylglycerol/phorbol ester-dependent but calcium-independent PKCs is essential for establishment of MCMV infection in the host cell, starting at a very early stage of infection.

scholarly journals Role of non-coding RNA networks in leukemia progression, metastasis and drug resistance

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Ajaz A. Bhat ◽  
Salma N. Younes ◽  
Syed Shadab Raza ◽  
Lubna Zarif ◽  
Sabah Nisar ◽  
...  
Keyword(s):  
Early Stage ◽  
Participation Rate ◽  
Prognostic Biomarkers ◽  
Critical Determinant ◽  
Functional Roles ◽  
Non Coding Rna ◽  
Non Coding Rnas ◽  
Low Sensitivity ◽  
Screening Approaches

AbstractEarly-stage detection of leukemia is a critical determinant for successful treatment of the disease and can increase the survival rate of leukemia patients. The factors limiting the current screening approaches to leukemia include low sensitivity and specificity, high costs, and a low participation rate. An approach based on novel and innovative biomarkers with high accuracy from peripheral blood offers a comfortable and appealing alternative to patients, potentially leading to a higher participation rate.Recently, non-coding RNAs due to their involvement in vital oncogenic processes such as differentiation, proliferation, migration, angiogenesis and apoptosis have attracted much attention as potential diagnostic and prognostic biomarkers in leukemia. Emerging lines of evidence have shown that the mutational spectrum and dysregulated expression of non-coding RNA genes are closely associated with the development and progression of various cancers, including leukemia. In this review, we highlight the expression and functional roles of different types of non-coding RNAs in leukemia and discuss their potential clinical applications as diagnostic or prognostic biomarkers and therapeutic targets.

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